NO, synthesized in endothelial cells by endothelial NO synthase (NOS 3), is believed to be an important endogenous pulmonary vasodilator substance that contributes to the normal low pulmonary vascular resistance. To selectively investigate the role of NOS 3 in the pulmonary circulation, mice with targeted disruption of the NOS 3 gene were studied. Pulmonary hemodynamics were studied by measuring pulmonary artery pressure, left ventricular end-diastolic pressure, and lower thoracic aortic flow by using a novel open-chest technique. Transient partial occlusion of the inferior vena cava was used to assess the pulmonary artery pressure-flow relationship. Tension developed by isolated pulmonary artery segments after acetylcholine stimulation was measured in vitro. The histological appearance of NOS 3-deficient and wild-type murine lungs was compared. NOS 3-deficient mice (n = 27), when compared with wild-type mice (n = 32), had pulmonary hypertension (pulmonary artery pressure, 19.0 +/- 0.8 versus 16.4 +/- 0.6 mm Hg [mean +/- SE]; P < .05) that was due to an increased total pulmonary resistance (62 +/- 6 versus 33 +/- 2 mm Hg.min.g.mL-1; P < .001). In vitro, acetylcholine induced vasodilation in the main pulmonary arteries of wild-type but not NOS 3-deficient mice. The morphology of the lungs of NOS 3-deficient mice did not differ from that of wild-type mice. We conclude that NOS 3 is a key enzyme responsible for providing basal pulmonary NO release. Congenital NOS 3 deficiency produces mild pulmonary hypertension in mice.

OBJECTIVE

To evaluate predictors of treatment discontinuation against medical advice and poor medication adherence among first-episode patients treated with olanzapine, quetiapine, or risperidone.

METHODS

First-episode patients with schizophrenia, schizophreniform disorder, or schizoaffective disorder (DSM-IV) were randomly assigned to olanzapine (2.5-20 mg/day), quetiapine (100-800 mg/day), or risperidone (0.5-4 mg/day) as part of a 52-week, randomized, double-blind, flexible-dose, multicenter study. Patients were enrolled from 2002 to 2004 at one of 26 sites in the United States and Canada. Survival analysis tested for predictors of treatment discontinuation against medical advice, while mixed models tested for predictors of poor medication adherence. Significant findings from the final models were replicated in sensitivity analyses.

RESULTS

Of the 400 patients randomly assigned to treatment, 115 patients who discontinued treatment against medical advice and 119 study completers were compared in this analysis. Poor treatment response (p < .001) and low medication adherence (p = .02) were independent predictors of discontinuation against medical advice. Ongoing substance abuse, ongoing depression, and treatment response failure significantly predicted poor medication adherence (p < .01). Higher cognitive performance at baseline and ethnicity (black) were also associated with lower medication adherence (p < .05). An association between poor medication adherence and illness insight at study entry was found at trend level (p = .059).

CONCLUSIONS

This study highlights the importance of treatment response in predicting discontinuation against medical advice and poor adherence to medication in first-episode patients. These results also support interventions to improve adherence behavior, particularly by targeting substance use disorders and depressive symptoms.

BACKGROUND

ClinicalTrials.gov identifier NCT00034892 (http://www.clinicaltrials.gov).

OBJECTIVE

To review all randomized clinical trials addressing the efficacy of clinical information systems and to determine the clinical settings, types of interventions, and effects studied.

METHODS

Extensive and systematic MEDLINE searches were conducted using a combination of medical subject headings (MeSH) and textword terms to collect trial reports. Manual searches of books and monographs as well as informal contacts were also used.

METHODS

The eligibility criteria were (1) randomized controlled clinical trial, (2) computerized information intervention in the study group, and (3) effect measured on the process or outcome of care.

METHODS

Two research assistants independently abstracted from the selected reports the following structured information: trial sites, computerized interventions, effect variables, and outcomes. Three investigators evaluated the combined list of trial features for setting, intervention, and effect. The statistical analysis included an evaluation of agreement in developing classifications and an analysis of the ratio of positive trial outcomes.

RESULTS

Most information services were tested in outpatient care (82%), particularly in primary care (66%). The information intervention targeted the provider in 64% of the trials. The effect was primarily measured for the process of care (76%). Provider prompt/reminder, computer-assisted treatment planner, interactive patient education/therapy, and patient prompt/reminder were significantly successful interventions (sign test, P < .05).

CONCLUSIONS

Randomized clinical trials confirm that four generic information interventions are active ingredients of computer systems and can make a significant difference in family medicine (physician and patient reminders, treatment planner, and patient education). To manage care and improve quality, primary care computer systems should incorporate these effective information services.

The temporal course of changes in peptide expression in the dorsal root ganglia L4 and L5 and in the dorsal horn of the spinal cord has been studied in rats subjected to a sciatic nerve transection at a mid-thigh level following different survival times. Galanin-, substance P-, vasoactive intestinal polypeptide-, peptide histidine-isoleucine- and calcitonin gene-related peptide-like immunoreactivities have been studied both by immunohistochemistry and radioimmunoassay. Galanin messenger ribonucleic acid has also been studied by in situ hybridization in the dorsal root ganglia of normal and lesioned animals. In addition, a group of animals with a sciatic nerve crush was studied to compare possible differences in peptide expression after both types of lesions. The results show that the transection induces an increase in the number of cell bodies expressing galanin-like immunoreactivity in the ganglia, and that the galanin levels rise about 120-fold after three and 14 days of survival. This increase reflected increased synthesis of the peptide, since there was a rise in the galanin messenger ribonucleic acid already at 24 h post-lesion, which was maintained for at least 60 days. In the spinal cord there was an increase of staining in the midportion of the outer layers of the dorsal horn that corresponded to fibers thought to arise from cells of the dorsal root ganglia affected by the transection. Also a depletion of substance P-like and an increase in vasoactive intestinal polypeptide- and peptide histidine-isoleucine-like immunoreactivities in the dorsal root ganglia were confirmed. These changes were shown to be rapidly detectable and were paralleled by similar changes in the dorsal horn of the spinal cord. For calcitonin gene-related peptide the immunohistochemistry was inconclusive, and the radioimmunoassay showed no detectable changes. After nerve crush a transient increase in the number of galanin immunoreactive neurons was observed, as well as a decrease in the number of neurons showing substance P-like immunoreactivity. These changes were most noticeable between six and 14 days of survival. After this, peptide expression seemed to return slowly to normal, that is by day 45 post-crush only a few cells showed galanin-like, and many sensory neurons expressed substance P-like immunoreactivity. The results demonstrate that when primary sensory neurons are peripherally lesioned they respond in a complex manner, altering their normal production of peptides by increasing or decreasing their synthesis.(ABSTRACT TRUNCATED AT 400 WORDS)

OBJECTIVE

To explore the presence of the neuropeptide substance P (SP) in the bladders of rats and humans and to investigate its relationship to mast cells (MCs) in interstitial cystitis (IC), a bladder disorder which occurs mostly in women and is characterized by frequency of voiding, nocturia and debilitating suprapubic pain.

METHODS

Bladder biopsies from eight women with untreated IC (mean age 36 years, range 29-58) and five control patients with no IC were analysed and compared with each other and with bladder tissue from 12 rats. Immunohistochemistry and image analysis were used to examine the density of SP-positive nerve fibres and their relationship with MCs.

RESULTS

SP-containing nerve fibres were present in the bladder of both rats and humans. They were increased only in the submucosa, but not in the detrusor, of IC patients and were frequently seen in juxtaposition to MCs.

CONCLUSIONS

SP, a neuropeptide secreted from sensory nerve endings, has been implicated in the pathophysiology of pain and has been shown to trigger MC secretion. Moreover, MC secretion by SP is augmented by oestradiol and bladder MCs have been shown to express high affinity oestrogen receptors. A functional relationship between SP and MCs may explain the pathophysiology of the neuro-inflammatory and painful nature of IC.

We have developed a technique which allows specific detection of proteins expressed from cloned genes. The method involves fusion of an oligonucleotide coding for part of the neuropeptide substance P to the 3' end of the gene; the protein can then be detected with a monoclonal antibody that recognises this peptide. We have used this method to determine the properties of deletion mutants of the major Drosophila heat shock protein, hsp70, expressed in monkey COS cells. The results suggest that this protein has two distinct domains. Both are capable of accumulating in the nucleus of unstressed cells, but only the more highly conserved N-terminal domain is able to bind to nucleoli following a heat shock. This implies that nucleolar binding and nuclear migration are distinct properties of the protein, and suggests that the former may be of functional importance. In addition, we observed a novel effect of heat shock on cellular metabolism: protein fragments that are normally rapidly degraded are stabilized. The effect persists for several hours after the heat shock, but does not require expression of heat shock proteins. Together with previously published data, these results suggest an intimate relationship between protein degradation and the heat shock response.

The rate of active transport by the proximal renal tubule of amino acid (L-histidine), sugar (alpha-methyl-D-glycoside), H+ ions (glycodiazine), phosphate and para-aminohippurate was evaluated by measuring the zero net flux concentration difference (deltac) of these substances. In the case of calcium the electrochemical potential difference (delta + zF-CIdeltaphi/RT) was the criterion employed. The rate of isotonic Na+-absorption (JNa) was measured with the shrinking droplet method. The effect of ouabain on the transport of these substances was tested in the golden hamster and the effect of SITS (4-acetamido-4'isothiocyanatostilbene 2,2'-disulfonic acid) was observed in rats. Ouabain (1 mM) applied peritubularly incompletely inhibited JNa (80%), but in combination with acetazolamide (0.2 mM) the inhibition was almost complete (93%). In addition, ouabain inhibited the sodium coupled (secondary active) transport processes of L-histidine, alpha-methyl-D-glycoside, calcium and phosphate by more than 75%. It did not affect H+ (glycodiazine) transport and PAH transport was only slightly affected. When SITS (1 mM) was applied from both sides of the cell it inhibited H+ (glycodiazine) transport by 72% and reduced JNa by 38% when given from only the peritubular cell side. SITS (1 MM), however, had no significant affect on H+ secretion and sodium reabsorption if it was applied from only the luminal side. Furthermore it had no affect on the other transport processes tested, regardless of the cell side to which it was applied. When the HCO-3 buffer or physically related buffers were omitted from the perfusate the absorption of Na+ was reduced by 66%, phosphate by 44%, and L-histidine by 15%. All the other transport processes tested were not significantly affected. The data are consistent with the hypothesis that the active transport processes of histidine, alpha-methyl-D-glycoside and phosphate, which are located in the brush border, are driven by a sodium gradient which is abolished by ouabain. This may also apply to the Na+-Ca2+ countertransport located at the contraluminal cell side. The residual Na+ transport remaining in the presence of ouabain is likely to be passively driven by the continuing H+ transport which probably is driven directly by ATP. SITS seems to inhibit the exit step of HCO-3 from the cell and secondary to that, the luminal H+-Na+ exchange and consequently the Na+ reabsorption. In the absence of HCO-3 buffer in the perfusates the luminal H+-Na+ exchange seems to be affected and the pattern of inhibition of the other transport processes is almost the same as with SITS. The different effects on Pi reabsorption observed under these conditions might be explained by possible variations in intracellular pH.

Toxin A, a 308,000-Mr enterotoxin from Clostridium difficile, mediates antibiotic-associated diarrhea and colitis in humans. Injection of toxin A into animal intestine triggers an acute inflammatory response characterized by activation of sensory neurons and immune cells of the intestinal lamina propria, including mast cells and macrophages, and migration of circulating neutrophils in the involved intestinal segment. In this study we show that mice genetically deficient in the neurokinin-1 receptor are protected from the secretory and inflammatory changes as well as from epithelial cell damage induced by toxin A. The protective effect of neurokinin-1R deletion correlates with diminished intestinal levels of the cytokine TNF-alpha and its mRNA and the leukocyte enzyme myeloperoxidase. These results demonstrate a major requirement for substance P receptors in the pathogenesis of acute inflammatory diarrhea.

The spinal cord is one of the sites where non-steroidal anti-inflammatory drugs (NSAIDs) act to produce analgesia and antinociception. Expression of cyclooxygenase(COX)-1 and COX-2 in the spinal cord and primary afferents suggests that NSAIDs act here by inhibiting the synthesis of prostaglandins (PGs). Basal release of PGD(2), PGE(2), PGF(2alpha) and PGI(2) occurs in the spinal cord and dorsal root ganglia. Prostaglandins then bind to G-protein-coupled receptors located in intrinsic spinal neurons (receptor types DP and EPPPPP). Acute and chronic peripheral inflammation, interleukins and spinal cord injury increase the expression of COX-2 and release of PGE(2) and PGI(2). By activating the cAMP and protein kinase A pathway, PGs enhance tetrodotoxin-resistant sodium currents, inhibit voltage-dependent potassium currents and increase voltage-dependent calcium inflow in nociceptive afferents. This decreases firing threshold, increases firing rate and induces release of excitatory amino acids, substance P, calcitonin gene-related peptide (CGRP) and nitric oxide. Conversely, glutamate, substance P and CGRP increase PG release. Prostaglandins also facilitate membrane currents and release of substance P and CGRP induced by low pH, bradykinin and capsaicin. All this should enhance elicitation and synaptic transfer of pain signals in the spinal cord. Direct administration of PGs to the spinal cord causes hyperalgesia and allodynia, and some studies have shown an association between induction of COX-2, increased PG release and enhanced nociception. NSAIDs diminish both basal and enhanced PG release in the spinal cord. Correspondingly, spinal application of NSAIDs generally diminishes neuronal and behavioral responses to acute nociceptive stimulation, and always attenuates behavioral responses to persistent nociception. Spinal application of specific COX-2 inhibitors sometimes diminishes behavioral responses to persistent nociception.

Intrastriatal injection of malonate, a reversible inhibitor of succinate dehydrogenase (SDH), produced age-dependent striatal lesions, which were significantly greater in 4- and 12-month-old animals than in 1-month-old animals. Both histologic and neurochemical studies showed that the lesions were significantly attenuated by administration of the noncompetitive NMDA receptor antagonist MK-801. Water-suppressed chemical shift magnetic resonance imaging showed that malonate produces increased striatal lactate concentrations and striatal lesions on T2-weighted scans that were attenuated by MK-801. Neurochemical characterization of the lesions showed significant decreases in markers of medium-sized spiny neurons (GABA and substance P), whereas a marker of medium-sized aspiny neurons (somatostatin) was not different from control values, consistent with an NMDA receptor-mediated mechanism. The effects of intrastriatal injections of malonate on ATP concentrations were compared with those of the irreversible SDH inhibitor 3-nitropropionic acid (3-NP). The ATP depletions following an equimolar injection of malonate were less marked and more transient than those of 3-NP. These results show that the competitive SDH inhibitor malonate produces more transient and milder bioenergetic defects than 3-NP, which are associated with selective activation of NMDA receptors. The results strengthen the possibility that a subtle impairment of energy metabolism may play a role in the pathogenesis of Huntington's disease.

OBJECTIVE

The level of intensity of response to a drug is likely to influence the future pattern of intake of the substance. This article evaluates a simple Self-Rating of the Effects (SRE) of alcohol form, and reports the relationship between a person's estimate of the amounts of alcohol usually required for four possible effects during three different time frames and his subjective feelings reported during an alcohol challenge.

METHODS

SRE forms and results of a challenge with 0.9 ml/kg (0.72 g/kg) of ethanol were available for 18 to 29 year old drinking, but not alcohol dependent, men (N = 98). A subset of 40 subjects completed a second SRE form approximately 1 year later.

RESULTS

The correlation between the two SRE administration was .82 (p < .0001), and the results on the SRE were internally consistent, with a higher number of drinks associated with more intense alcohol effects. Focusing on the subjective feelings reported at the 60-minute timepoint during the alcohol challenge, 11 of the 12 alcohol effect categories on the SRE correlated in the predicted direction, including eight that were statistically significant. Evaluating all seven timepoints during the drinking experiment, the average number of drinks on the SRE correlated significantly with the Subjective High Assessment Scale (SHAS) total score at all but the final timepoint. Sons of alcoholics and controls demonstrated similar levels of correlation between SRE and alcohol challenge results. Finally, the SRE correctly identified 79% of the individuals whose levels of response to alcohol fell into the lowest third of intensity during the alcohol challenge, and it correctly classified 60% to 67% of the alcohol challenge subjects who did not fall into that low response category.

CONCLUSIONS

The SRE is a simple and reliable measure of a person's estimate of the number of drinks required to achieve a response. The form might be helpful in educating people about the intensity of their response to alcohol and might be useful as a point of discussion in curricula focusing on genetic aspects of alcoholism. When alcohol challenges are not possible in a research protocol, the SRE might help identify a less heterogeneous subgroup of individuals at high risk for alcoholism who have a common mechanism increasing their vulnerability.

OBJECTIVE

Little is known about the risks and characteristics of attention-deficit/hyperactivity disorder (ADHD) patients who misuse or divert their stimulant medications. As part of a 10-year longitudinal study of youths with ADHD, the authors evaluated medication diversion or misuse at the last follow-up period.

METHODS

Structured psychiatric interviews for diagnosis and a self-report questionnaire regarding medication use in medicated subjects with ADHD compared with controls without ADHD receiving psychotropics for non-ADHD treatment were employed.

RESULTS

Of 98 subjects receiving psychotropic medications (mean age of 20.8 +/- 5 years), 55 (56%) were ADHD subjects and 43 (44%) were controls receiving medications for other purposes. The authors found that 11% of the ADHD group reported selling their medications compared with no subjects in the control group (z = 0.00, p <.05). An additional 22% of the ADHD group reported misusing their medications compared with 5% of the control subjects (z = 1.7 p =.09) and that those with conduct or substance use disorders accounted for the misuse and diversion. A minority of subjects reported escalating their doses and concomitant use with alcohol and drugs.

CONCLUSIONS

The data indicate that the majority of ADHD individuals, particularly those without conduct or substance use disorders, use their medications appropriately. The authors' findings also highlight the need to monitor medication use in ADHD individuals with conduct and/or substance use disorders and to carefully select agents with a low likelihood of diversion or misuse in this group.

1. The present experiments examine the physiology and pharmacology of the release of substance P-like immunoreactivity (SP-l.i.), from the spinal cord in the halothane-anaesthetized, artificially ventilated cat. 2. Resting release of SP-l.i. was 36 +/- 4 fmol/30 min (mean +/- S.E.; n = 106). Bilateral stimulation of the sciatic nerves at intensities which evoked activity in fibres conducting at A beta conduction velocities (greater than 40 m/s), resulted in no change in blood pressure, pupil diameter or release of SP-l.i. Stimulation intensities which activate fibres conducting at velocities less than 2 m/s resulted in increased blood pressure, miosis and elevated release of SP-l.i. (278 +/- 16% of control). 3. The relationship between nerve-stimulation frequency and release was monotonic up to approximately 20 Hz. Higher stimulation frequencies did not increase the amounts of SP-l.i. released. At 200 Hz there was a reduction. 4. Capsaicin (0.1 mM) increased the release of SP-l.i. from the spinal cord and resulted in an acute desensitization to subsequent nerve stimulation. This acute effect was not accompanied by a reduction in spinal levels of SP-l.i. measured 2 h after stimulation. 5. Cold block of the cervical spinal cord resulted in an increase in the amounts of SP-l.i. released by nerve stimulation. 6. Pre-treatment with intrathecal 5,6-dihydroxytryptamine (300 micrograms) 7 days prior to the experiment caused a reduction in the dorsal and ventral horn stores of SP-l.i., but had no effect on the release of SP-l.i. evoked by nerve stimulation. Similar pre-treatment with intrathecal capsaicin (300 micrograms) resulted in depletion of SP-l.i. in the dorsal but not in the ventral horn of the spinal cord and diminished the release of SP-l.i. evoked by nerve stimulation. 7. Intense thermal stimulation of the flank resulted in small (20-35%), but reliable increases in the release of SP-l.i. above control. 8. Putative agonists for the opioid mu-receptor (morphine, 10-100 microM; sufentanil, 1 microM), and for the delta-receptor (D-Ala2-D-Leu5-enkephalin, 1-10 microM; D-Pen2-D-Pen5-enkephalin, 10 microM), but not the kappa-receptor (U50488H, 100-1000 microM), produced a dose-dependent, naloxone-reversible reduction of the evoked, but not of the resting release of SP-l.i. (-)-Naloxone, but not (+)-naloxone, resulted in a significant increase in evoked but not resting SP-l.i. release.(ABSTRACT TRUNCATED AT 400 WORDS)

The origin of substance P (SP)-immunoreactive neurons in the lower respiratory tract, esophagus and heart of guinea-pigs was demonstrated by surgical denervation or capsaicin pretreatment with subsequent determination of the tissue levels of SP by radioimmunoassay. In other experiments the effect of vagal nerve stimulation on the SP levels in these tissues was studied. The effects of capsaicin-sensitive afferents in the respiratory tract mucosa and bronchial smooth muscle was also studied by analysis of vascular permeability to Evans blue and insufflation-pressure changes. Our present data indicate that all SP nerves in the trachea and lung are afferent and capsaicin-sensitive. The trachea and stem bronchi receive SP afferents mainly from the right vagus nerve with cell bodies located in both the nodose and jugular ganglia. The SP innervation of the lung seems to have a dual origin: 1. Afferents from both vagal nerves with a crossed type of innervation pattern. 2. A non-vagal source which consists of about 40% of the SP nerves in the lung. These nerves probably originate from thoracic spinal ganglia. The effects of ether and capsaicin on insufflation pressure and increase in vascular permeability were dependent on the integrity of capsaicin-sensitive afferents of both vagal and non-vagal origin. In the guinea pig, systemic capsaicin pretreatment to adult animals seemed to result in irreversible changes in the respiratory tract, while in the rat a successive recovery of the functional response of capsaicin-sensitive afferents occurred. Different regimes of systemic capsaicin pretreatment induced different effects on the cholinergic (atropine-sensitive) insufflation-pressure response. Capsaicin pretreatment, using multiple injections over two days, depressed the cholinergic insufflation-pressure increase, while the cholinergic vagal component was unaffected in animals which received a single dose of capsaicin or local pretreatment with capsaicin on the vagal nerves. The local treatment was more effective with regard to SP depletion in target areas when using alcohol as solvent than when capsaicin was dissolved in paraffin oil, while the functional deficits were similar. The SP nerves in the esophagus were mainly of vagal afferent origin, while the heart atrium seemed to have a dual innervation by both vagal and non-vagal SP nerves.

Previous findings have shown that the capsaicin sensitivity of sensory fibres is due to the expression of a specific membrane protein, the vanilloid receptor type 1 (VR1). In the present work we studied the distribution, morphology and the neurochemical content of nerve fibres expressing this receptor in the rat urinary tract. Immunolabelling was performed against the VR1 and the positive fibres were examined by light and electron microscopy. Colocalisation of VR1 and substance P or calcitonin gene-related peptide immunoreactivities, and isolectin B4 binding, was evaluated under the confocal microscope. In addition, the effect of intravesical administration of resiniferatoxin, an ultra-potent vanilloid receptor agonist, in the receptor expression in the bladder was also studied. Numerous VR1-immunoreactive fibres were found in the mucosa and muscular layer of the entire urinary tract except the kidney. In the bladder, most fibres were also substance P- or calcitonin gene-related peptide-immunoreactive but did not bind isolectin B4. Under the electron microscope VR1 immunoreactivity was confined to unmyelinated axons and varicosities containing small clear and large dense-core synaptic vesicles. They occurred beneath or among epithelial cells or closely apposed to smooth muscle cells. Intravesical resiniferatoxin decreased VR1 immunoreactivity transiently. These data indicate that primary sensory fibres expressing VR1 are extremely abundant in the rat urinary tract and that, in contrast to the skin, they belong almost exclusively to the peptide-containing sub-population of primary afferents. As capsaicin-sensitive bladder afferents are involved in nociception and reflex micturition control, the numerous free terminal nerve endings expressing VR1 in the mucosa seem more adequate to accomplish the former function. However, the close apposition between VR1-expressing fibres and smooth muscle cells suggests that they may also encode the tonus of the muscular layer.

BACKGROUND

Few studies have investigated risk factors for suicidal ideation and attempts, or possible variations in them, among representative samples of psychiatric patients with major depressive disorder.

METHODS

As part of the Vantaa Depression Study in Vantaa, Finland, 269 patients with DSM-IV major depressive disorder (MDD), diagnosed by interview using semistructured World Health Organization Schedules for Clinical Assessment in Neuropsychiatry, version 2.0, and Structured Clinical Interview for DSM-III-R Personality Disorders, were thoroughly investigated. Information was gathered on patients' levels of depression, anxiety, hopelessness, perceived social support, social and occupational functioning, and alcohol use. Suicidal behavior was assessed by interviews, including the Scale for Suicidal Ideation, and by information from psychiatric records. Data were gathered from Feb. 1, 1997, to May 31, 1998.

RESULTS

During the current MDD episode, 58% of all patients had experienced suicidal ideation; among the 15% of the total who had attempted suicide, almost all (95%) had also had suicidal ideation. In nominal regression models predicting suicidal ideation, hopelessness, alcohol dependence or abuse, low level of social and occupational functioning, and poor perceived social support were found to be significant (p < .05) independent risk factors. High severity of depression and current alcohol dependence or abuse in particular, but also younger age and low level of social and occupational functioning, predicted suicide attempt.

CONCLUSIONS

Suicidal ideation is prevalent and appears to be a precondition for suicide attempts among psychiatric patients with MDD. The risk factors for suicidal ideation and attempts locate in several clinical and psychosocial domains. While these risk factors largely overlap, the overall level of psychopathology of suicide attempters is higher compared with that in patients with ideation, and substance use disorders and severity of depression may be of particular importance in predicting suicide attempts.

OBJECTIVE

To determine the effect of botulinum toxin type A (BTX-A) on the release of the neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) from isolated bladder preparations after acute injury with HCl and the induction of cyclophosphamide (CYP)-induced cystitis, as neurogenic inflammation has been increasingly identified in urological disorders such as interstitial cystitis.

METHODS

Adult rats had either an intraperitoneal injection with CYP or saline over a 10-day period to induce chronic bladder inflammation, after which the bladder was harvested, or normal bladder explants were injured acutely with incubation (20 s) in HCl (0.4 m). To measure the effect of BTX-A on the release of neurotransmitters, harvested bladders were incubated in an organ bath containing BTX-A (10 U) or vehicle. Bladders were transferred to a subsequent bath (physiological saline) and incubated for 15 min, and the bathing medium analysed to measure neurotransmitter release, as determined by radioimmunoassay. Bladder specimens from sham treatment, controls and experimental rats were compared histologically.

RESULTS

Acute injury with HCl caused a significantly greater release of both CGRP and SP release (1235 and 1655 pg/g, respectively) than in controls (183 and 449 pg/g, respectively; P < 0.001). This increase in neurotransmitter release was partly inhibited by exposure to BTX-A (870 and 1033 pg/g (P < 0.05 and <0.01). CYP-induced chronic inflammation caused significantly greater release of SP than in the controls (1060 and 605 pg/g, respectively; P < 0.005). Exposure to BTX-A partly inhibited the release of SP after CYP-induced cystitis (709 pg/g, P < 0.05).

CONCLUSIONS

The application of BTX-A inhibits the release of sensory neurotransmitters from isolated bladder preparations in rat bladder models of both acute injury and chronic inflammation, suggesting a potential clinical benefit of BTX-A in the treatment of neurogenic inflammation.

alpha2-Adrenergic receptors (alpha2-ARs) mediate a number of physiological phenomena, including spinal analgesia. We have developed subtype-selective antisera against the C termini of the alpha2A-AR and alpha2C-AR to investigate the relative distribution and cellular source or sources of these receptor subtypes in the rat spinal cord. Immunoreactivity (IR) for both receptor subtypes was observed in the superficial layers of the dorsal horn of the spinal cord. Our results suggest that the primary localization of the alpha2A-AR in the rat spinal cord is on the terminals of capsaicin-sensitive, substance P (SP)-containing primary afferent fibers. In contrast, the majority of alpha2C-AR-IR was not of primary afferent origin, not strongly colocalized with SP-IR, and not sensitive to neonatal capsaicin treatment. Spinal alpha2C-AR-IR does not appear to colocalize with the neurokinin-1 receptor, nor is it localized on astrocytes, as evidenced by a lack of costaining with the glial marker GFAP. However, some colocalization was observed between alpha2C-AR-IR and enkephalin-IR, suggesting that the alpha2C-AR may be expressed by a subset of spinal interneurons. Interestingly, neither subtype was detected on descending noradrenergic terminals. These results indicate that the alpha2-AR subtypes investigated are likely expressed by different subpopulations of neurons and may therefore subserve different physiological functions in the spinal cord, with the alpha2A-AR being more likely to play a role in the modulation of nociceptive information.

Agonists acting at alpha2 adrenergic and opioid receptors have analgesic properties and act synergistically when co-administered in the spinal cord; this synergy may also contribute to the potency and efficacy of spinally administered morphine. The lack of subtype-selective pharmacological agents has previously impeded the definition of the adrenergic receptor subtype(s) mediating these effects. We therefore exploited a genetically modified mouse line expressing a point mutation (D79N) in the alpha2a adrenergic receptor (alpha2aAR) to investigate the role of the alpha2aAR in alpha2 agonist-evoked analgesia and adrenergic-opioid synergy. In the tail-flick test, intrathecal administration of UK 14,304, a nonsubtype-selective alpha2AR agonist, had no analgesic effect in D79N mice, whereas the analgesic potency of morphine (intrathecal) in this assay was not affected by the mutation. The mutation also decreased alpha2-agonist-mediated spinal analgesia and blocked the synergy seen in wild-type mice with both the delta-opioid agonist deltorphin II and the micro-opioid agonist [D-ALA2,N-Me-Phe4, Gly-ol5]-Enkephalin (DAMGO) in the substance P behavioral test. In addition, the potency of spinally administered morphine was decreased in this test, suggesting that activation of descending noradrenergic systems impinging on the alpha2aAR contributes to morphine-induced spinal inhibition in this model. These results demonstrate that the alpha2aAR subtype is the primary mediator of alpha2 adrenergic spinal analgesia and is necessary for analgesic synergy with opioids. Thus, combination therapies targeting the alpha2aAR and opioid receptors may prove useful in maximizing the analgesic efficacy of opioids while decreasing total dose requirements.

The structural basis of phosphorylation and its putative role in internalization were investigated in the human dopamine transporter (hDAT). Activation of protein kinase C (PKC) was achieved either directly by treatment with 4-alpha-phorbol 12-myristate 13-acetate (PMA) or by activating the Galpha(q)-coupled human substance P receptor (hNK-1) co-expressed with hDAT in HEK293 cells and in N2A neuroblastoma cells. In both cell lines, activation of the hNK-1 receptor by substance P reduced the V(max) for [(3)H]dopamine uptake to the same degree as did PMA ( approximately 50 and approximately 20% in HEK293 and N2A cells, respectively). In HEK293 cells, the reduction in transport capacity could be accounted for by internalization of the transporter, as assessed by cell surface biotinylation experiments, and by fluorescence microscopy using enhanced green fluorescent protein-tagged hDAT. In HEK293 cells, hNK-1 receptor activation, as well as direct PKC activation by PMA, was accompanied by a marked increase in transporter phosphorylation. However, truncation of the first 22 N-terminal residues almost abolished detectable phosphorylation without affecting the SP- or PMA-induced reduction in transport capacity and internalization. In this background truncation construct, systematic mutation of all the phosphorylation consensus serines and threonines in hDAT, alone and in various combinations, did also not alter the effect of hNK-1 receptor activation or PMA treatment in either HEK293 or N2A cells. Mutation of a dileucine and of two tyrosine-based motifs in hDAT was similarly without effect. We conclude that the major phosphorylation sites in hDAT are within the distal N terminus, which contains several serines. Moreover, the present data strongly suggest that neither this phosphorylation, nor the phosphorylation of any other sites within hDAT, is required for either receptor-mediated or direct PKC-mediated internalization of the hDAT.

The distribution of substance P (SP) immunoreactivity in the spinal nucleus of the rat trigeminal nerve and in the skin of the lower lip was examined following (a) unilateral electrolytic lesions of the trigeminal ganglion, (b) trigeminal rhizotomy, and (c) unilateral interruption of the mental nerve, the sensory branch of the trigeminal nerve innervating the lower lip. A marked depletion of SP immunoreactivity in the ipsilateral trigeminal spinal nucleus followed lesions of the trigeminal ganglion or rhizotomy. The reticular formation ventral and medial to the spinal nucleus showed a small decrease in SP immunofluorescence on the operated side. Some loss of SP immunoreactivity was observed in the skin of the lower lip following ganglionectomy or rhizotomy. After sectioning the mental branch SP-immunofluorescent fibres of the skin of the lower lip disappear completely on the denervated side. It was concluded that some trigeminal ganglion neurones store, and might release, SP at their axon terminals in the medulla oblongata and at their sensory terminals in the skin.

The occurrence of tachykinins in sensory neurons of the guinea-pig was studied by means of radioimmunoassay combined with ion-exchange and high-performance liquid chromatography as well as by immunohistochemistry. Antisera raised against kassinin (antiserum K12), neurokinin A (NKA) (antiserum NKA2) and substance P (SP) (antisera SPPPK) and a component eluting in the position of eledoisin (ELE) in extracts of the lung and ureter. Neurokinin B (NKB) was, however, not found. Neutral water extraction favored recovery of NKA and of the ELE-like component, while NPK was found only in acid extracts. The SP antisera detected two immunoreactive components of which the major form coeluted with synthetic SP. Capsaicin pretreatment depleted all these various forms of immunoreactivity in several peripheral organs including the ureter and lung. The immunoreactivity detected by antisera K12 or SPPP, NKA, NPK and an ELE-like peptide, are present in capsaicin-sensitive sensory nerves in the guinea-pig. This finding can most likely be related to the origin of SP, NKA and NPK from the same precursor molecule, subsequent posttranslational tissue processing and axonal transport to terminal regions.

OBJECTIVE

To examine the effects of acute insulin-induced hypoglycemia on inflammation, endothelial dysfunction, and platelet activation in adults with and without type 1 diabetes.

METHODS

We studied 16 nondiabetic adults and 16 subjects with type 1 diabetes during euglycemia (blood glucose 4.5 mmol/l) and hypoglycemia (blood glucose 2.5 mmol/l). Markers of inflammation, thrombosis, and endothelial dysfunction (soluble P-selectin, interleukin-6, von Willebrand factor [vWF], tissue plasminogen activator [tPA], high-sensitivity C-reactive protein [hsCRP], and soluble CD40 ligand [sCD40L]) were measured; platelet-monocyte aggregation and CD40 expression on monocytes were determined using flow cytometry.

RESULTS

In nondiabetic participants, platelet activation occurred after hypoglycemia, with increments in platelet-monocyte aggregation and <em>P</em>-selectin (<em>P</em> <or= 0.02). Inflammation was triggered with CD40 expression increasing maximally at 24 h (3.13 +/- 2.3% vs. 2.06 +/- 1.0%) after hypoglycemia (<em>P</em> = 0.009). Both sCD40L and hsCR<em>P</em> (<em>P</em> = 0.02) increased with a nonsignificant rise in vWF and t<em>P</em>A, indicating a possible endothelial effect. A reduction in sCD40L, t<em>P</em>A, and <em>P</em>-selectin occurred during euglycemia (<em>P</em> = 0.03, <em>P</em> <or= 0.006, and <em>P</em> = 0.006, respectively). In type 1 diabetes, both CD40 expression (5.54 +/- 4.4% vs. 3.65 +/- 1.8%; <em>P</em> = 0.006) and plasma sCD40L concentrations increased during hypoglycemia (peak 3.41 +/- 3.2 vs. 2.85 +/- 2.8 ng/ml; <em>P</em> = 0.03). <em>P</em>latelet-monocyte aggregation also increased significantly at 24 h after hypoglycemia (<em>P</em> = 0.03). A decline in vWF and <em>P</em>-selectin occurred during euglycemia (<em>P</em> <or= 0.04).

CONCLUSIONS

Acute hypoglycemia may provoke upregulation and release of vasoactive substances in adults with and without type 1 diabetes. This may be a putative mechanism for hypoglycemia-induced vascular injury.

Data on motor behavioural disorders induced by systemic 3-nitropropionic acid, an irreversible inhibitor of mitochondrial succinate dehydrogenase and their histopathological correlates in mice, are sparse. We thus further characterised the subacute 3-nitropropionic-acid-induced motor disorder and its time course in C57Bl/6 mice using standard behavioural tests, histopathological correlates and in vivo magnetic resonance imaging. Firstly, we studied two intoxication paradigms (340 and 560 mg 3-nitropropionic acid/kg, 7 days) compared to controls. The low-dose regimen induced only slight motor changes (reduced hindlimb stride length and rearing). The high-dose regimen induced significant (P<0.05) behavioural and sensorimotor integration deficits (pole test, rotarod, stride length, open-field spontaneous activity) but with 37.5% lethality at week one. The clinical motor disorder consisted of hindlimb clasping and dystonia, truncal dystonia, bradykinesia and impaired postural control. Histopathologically, there were discrete lesions of the dorsolateral striatum in 62.5% of mice together with a 32% reduction (P<0.0001) of the striatal volume, reduced caldbindin-D28K immunoreactivity in the lateral striatum, and met-enkephalin and substance P in the striatal output pathways. There was also a significant (P<0.05) 30-40% dopaminergic cell loss within the substantia nigra pars compacta. Secondly, we validated a semi-quantitative behavioural scale to describe the time course of the motor deficits and to predict the occurrence of striatal damage. We sought to determine whether it could also be disclosed in vivo by magnetic resonance imaging. The scale correlated with the striatal volume reduction (r(2)=0.57) and striatal cell loss (r(2)=0.87) but not with the loss of striatal dopaminergic terminals (dopamine transporter binding). Increased T2-signal intensity within the striatal lesion correlated with the cell loss (r(2)=0.66). We conclude that systemic administration of 3-nitropropionic acid in C57Bl/6 mice induces a distinct motor disorder and dose-dependent striatonigral damage, which are potentially useful to model human diseases of the basal ganglia.