BACKGROUND

As those with HIV infection live longer, 'non-AIDS' condition associated with immunodeficiency and chronic inflammation are more common. We ask whether 'non-HIV' biomarkers improve differentiation of mortality risk among individuals initiating combination antiretroviral therapy (cART).

METHODS

Using Poisson models, we analysed data from the Veterans Aging Cohort Study (VACS) on HIV-infected veterans initiating cART between 1 January 1997 and 1 August 2002. Measurements included: HIV biomarkers (CD4 cell count, HIV RNA and AIDS-defining conditions); 'non-HIV' biomarkers (haemoglobin, transaminases, platelets, creatinine, and hepatitis B and C serology); substance abuse or dependence (alcohol or drug); and age. Outcome was all cause mortality. We tested the discrimination (C statistics) of each biomarker group alone and in combination in development and validation data sets, over a range of survival intervals, and adjusting for missing data.

RESULTS

Of veterans initiating cART, 9784 (72%) had complete data. Of these, 2566 died. Subjects were middle-aged (median age 45 years), mainly male (98%) and predominantly black (51%). HIV and 'non-HIV' markers were associated with each other (P < 0.0001) and discriminated mortality (C statistics 0.68-0.73); when combined, discrimination improved (P < 0.0001). Discrimination for the VACS Index was greater for shorter survival intervals [30-day C statistic 0.86, 95% confidence interval (CI) 0.80-0.91], but good for intervals of up to 8 years (C statistic 0.73, 95% CI 0.72-0.74). Results were robust to adjustment for missing data.

CONCLUSIONS

When added to HIV biomarkers, 'non-HIV' biomarkers improve differentiation of mortality. When evaluated over similar intervals, the VACS Index discriminates as well as other established indices. After further validation, the VACS Index may provide a useful, integrated risk assessment for management and research.

Fried ground beef contains substances that inhibit mutagenesis in bacteria and the initiation of epidermal carcinogenesis in mice by 7,12-dimethylbenz [a]anthracene (DMBA). The inhibitors apparently act at least in part via inhibition of cytochrome P-450 activity. A highly purified fraction that inhibited cytochrome P-450 activity in vitro was isolated by HPLC and characterized by GC-MS, and by UV and proton NMR spectroscopy. The fraction contained four isomeric derivatives of linoleic acid each containing a conjugated double-bond system (designated CLA). Synthetically prepared CLA (containing all four isomers) was tested for anti-initiation activity in the two-stage mouse epidermal carcinogenesis system. Seven days, 3 days and 5 min prior to DMBA application, CLA was applied at doses of 20, 20 and 10 mg respectively. Control mice were treated similarly with linoleic acid or solvent (acetone). One week after initiation, and twice weekly thereafter, all mice were treated with 12-O-tetradecanoylphorbol-13-acetate to effect tumor promotion. There was no difference in tumor incidence or yield between linoleic acid-treated mice and solvent-treated control mice. By contrast, the CLA-treated mice developed only about half as many papillomas and exhibited a lower tumor incidence compared with the control mice.

Identifying genes for bipolar mood disorders through classic genetics has proven difficult. Here, we present a comprehensive convergent approach that translationally integrates brain gene expression data from a relevant pharmacogenomic mouse model (involving treatments with a stimulant--methamphetamine, and a mood stabilizer--valproate), with human data (linkage loci from human genetic studies, changes in postmortem brains from patients), as a bayesian strategy of crossvalidating findings. Topping the list of candidate genes, we have DARPP-32 (dopamine- and cAMP-regulated phosphoprotein of 32 kDa) located at 17q12, PENK (preproenkephalin) located at 8q12.1, and TAC1 (tachykinin 1, substance P) located at 7q21.3. These data suggest that more primitive molecular mechanisms involved in pleasure and pain may have been recruited by evolution to play a role in higher mental functions such as mood. The analysis also revealed other high-probability candidates genes (neurogenesis, neurotrophic, neurotransmitter, signal transduction, circadian, synaptic, and myelin related), pathways and mechanisms of likely importance in pathophysiology.

Acute pancreatitis may be initiated in the ex vivo, perfused canine pancreas preparation by a variety of stimuli. These include oleic acid infusion (FFA), partial duct obstruction with secretin stimulation (POSS), and a 2-hour period of ischemia (ISCH). In each model, pancreatitis is characterized by weight gain, edema, and hyperamylasemia. Oxygen-derived free radicals such as superoxide, hydrogen peroxide, and the hydroxyl radical are highly reactive toxic substances that are normally produced in small amounts during oxidative metabolism. Ordinarily, these substances are detoxified by endogenous intracellular enzymes called free radical scavengers (FRS), such as superoxide dismutase (SOD) and catalase (CAT). These studies were undertaken to evaluate the possible role of oxygen-derived free radicals in the initiation of acute pancreatitis in the isolated canine model. All preparations were perfused for 4 hours with autologous blood. Controls (N = 6): these glands remained normal in appearance, gained minimal weight (6 +/- 1 g), and serum amylase remained normal (less than 1000 u/dl). FFA pancreatitis, FFA alone (N = 6): these glands became edematous, gained weight (113.5 +/- 27.0 g), and developed hyperamylasemia (2087 +/- 387 u/dl). FFA + FRS (N = 6), SOD (50 mg) and CAT (50 mg) were added to the perfusate at time zero: these glands became only minimally edematous, gained less weight (31.8 +/- 10.1 g, p less than 0.05), and amylase remained normal (p less than 0.05). POSS pancreatitis, POSS alone (N = 8): these glands became edematous, gained weight (38.6 +/- 4.6 g), and developed marked hyperamylasemia (9522 +/- 3226 u/dl). POSS + FRS (N = 6): these glands did not develop edema, gained less weight (15.1 +/- 2.6 g, p less than 0.05), and serum amylase only increased to 1815 +/- 343 u/dl, (p less than 0.05). ISCH pancreatitis, ISCH alone (N = 6): these glands became edematous, gained weight (75.8 +/- 25 g), and developed hyperamylasemia (1679 +/- 439 u/dl). ISCH + FRS (N = 6): these glands did not develop edema, gained only 18.3 +/- 9.0 g (p less than 0.005), and serum amylase remained normal (p less than 0.05). These studies demonstrate that, in this canine preparation, acute pancreatitis is significantly ameliorated by oxygen-free radical scavengers. Since this was true whether the pancreatitis was produced by FFA infusion, POSS, or ischemia, it suggests that oxygen-derived free radicals may mediate a common essential step in the pathogenesis of all forms of pancreatitis.

Marijuana is the most widely used illicit substance in the United States; however, previous imaging studies have not detected altered brain structure in marijuana users compared to non-users. Voxel-based morphometry was used to investigate possible differences in brain tissue composition in a group of 11 heavy marijuana users and a group of 8 non-users. All participants were male. Statistical comparisons were made at the voxel level on T1-weighted magnetic resonance images to determine differences in gray matter and white matter tissue density. Compared to non-users, marijuana users had lower gray matter density in a cluster of voxels in the right parahippocampal gyrus (P = 0.0001), and greater density bilaterally near the precentral gyrus and the right thalamus (P < 0.04). Marijuana users also had lower white matter density in the left parietal lobe (P = 0.03), and higher density around the parahippocampal and fusiform gyri on the left side compared to non-users (P < 0.002). Longer duration of marijuana use (in years) was significantly correlated with higher white matter tissue density in the left precentral gyrus (P = 0.045). Our preliminary results suggest evidence of possible structural differences in the brain of heavy marijuana users, and localize regions for further investigation of the effects of marijuana in the brain.

The peptide substance P (SP) has been implicated in inflammatory conditions, such as psoriasis, where mast cells and VEGF are increased. A relationship between SP and VEGF has not been well studied, nor has any interaction with the proinflammatory cytokines, especially IL-33. Here we report that SP (0.1-10 microM) induces gene expression and secretion of VEGF from human LAD2 mast cells and human umbilical core blood-derived cultured mast cells (hCBMCs). This effect is significantly increased by coadministration of IL-33 (5-100 ng/mL) in both cell types. The effect of SP on VEGF release is inhibited by treatment with the NK-1 receptor antagonist 733,060. SP rapidly increases cytosolic calcium, and so does IL-33 to a smaller extent; the addition of IL-33 augments the calcium increase. SP-induced VEGF production involves calcium-dependent PKC isoforms, as well as the ERK and JNK MAPKs. Gene expression of IL-33 and histidine decarboxylase (HDC), an indicator of mast cell presence/activation, is significantly increased in affected and unaffected (at least 15 cm away from the lesion) psoriatic skin, as compared with normal control skin. Immunohistochemistry indicates that IL-33 is associated with endothelial cells in both the unaffected and affected sites, but is stronger and also associated with immune cells in the affected site. These results imply that functional interactions among SP, IL-33, and mast cells leading to VEGF release contribute to inflammatory conditions, such as the psoriasis, a nonallergic hyperproliferative skin inflammatory disorder with a neurogenic component.

Current cocaine users show little evidence of cognitive impairment and may perform better when using cocaine, yet withdrawal from prolonged cocaine use unmasks dramatic cognitive deficits. It has been suggested that such impairments arise in part through drug-induced dysfunction within the orbitofrontal cortex (OFC), yet the neurobiological mechanisms remain unknown. We observed that chronic cocaine self-administration increased expression of the transcription factor deltaFosB within both medial and orbitofrontal regions of the rat prefrontal cortex. However, the increase in OFC deltaFosB levels was more pronounced after self-administered rather than experimenter-administered cocaine, a pattern that was not observed in other regions. We then used rodent tests of attention and decision making to determine whether deltaFosB within the OFC contributes to drug-induced alterations in cognition. Chronic cocaine treatment produced tolerance to the cognitive impairments caused by acute cocaine. Overexpression of a dominant-negative antagonist of deltaFosB, deltaJunD, in the OFC prevented this behavioral adaptation, whereas locally overexpressing deltaFosB mimicked the effects of chronic cocaine. Gene microarray analyses identified potential molecular mechanisms underlying this behavioral change, including an increase in transcription of metabotropic glutamate receptor subunit 5 and GABA(A) receptors as well as substance P. Identification of deltaFosB in the OFC as a mediator of tolerance to the effects of cocaine on cognition provides fundamentally new insight into the transcriptional modifications associated with addiction.

Nitric oxide derived from vascular endothelium is a potent vasodilator that plays a key role in the homeostasis of blood pressure. Because cirrhotic patients tend to have low arterial pressure, we measured in 51 patients and 10 control subjects serum nitrite and nitrate levels as an index of in vivo nitric oxide generation. We also measured plasma endotoxin, a substance frequently increased in cirrhotic patients and known to induce nitric oxide synthesis. Cirrhotic patients showed significant increases in serum nitrite/nitrate and plasma endotoxin compared with controls. Values were particularly increased in patients with decompensated cirrhosis, as manifested by ascites with or without functional kidney failure. High serum nitrite/nitrate levels were associated with high plasma renin activity, high aldosterone and antidiuretic hormone levels and low urinary excretion of sodium. In addition, serum nitrite/nitrate levels significantly correlated with endotoxemia. Oral administration of colistin to 15 cirrhotic patients reduced significantly plasma endotoxin levels (p < 0.01) and serum nitrite/nitrate levels (p < 0.05). Because endotoxin enhances the expression of inducible nitric oxide synthase, our results suggest that circulating endotoxin in cirrhosis is responsible for excessive synthesis and release of nitric oxide by the vasculature. These findings might explain the hemodynamic dysfunction seen in cirrhotic patients.

The generation of knock-out and transgenic mice offers a promising approach to the identification of novel biochemical factors that contribute to persistent pain conditions. To take advantage of these mice, however, it is important to demonstrate that the traditional models of persistent pain, which were largely developed for studies in the rat, can be used in the mouse. Here, we combined behavioral and anatomical methods to characterize the pathophysiology of a partial nerve injury-evoked pain condition in the 'normal' mouse. In male C57BL6 mice we tied a tight ligature around 1/3 to 1/2 of the diameter of the sciatic nerve and evaluated the time-course and magnitude of the ensuing mechanical and thermal allodynia. We also used immunocytochemistry to analyze nerve injury-induced changes in substance P (SP) and NK-1 (SP) receptor expression in the spinal cord. As in the rat, partial nerve injury markedly decreased paw withdrawal thresholds to both mechanical and thermal stimuli on the injured side. We detected threshold changes one day after the injury. The thermal allodynia resolved by 49 days, but the mechanical allodynia persisted for the duration of the study (70 days). We found no changes contralateral to the nerve injury. Sympatholytic treatment with guanethidine significantly reduced both the thermal and mechanical allodynia. We observed a reduction of SP immunoreactivity in the superficial dorsal horn on the injured side at 7 and 14, but not at 3 or 70 days after the nerve injury, and we observed an increase of NK-1 receptor expression at 3, 7, 14 and 42, but not at 70 days after the injury. We conclude that partial injury to the sciatic nerve produces a comparable allodynia and neurochemical plasticity in the rat and mouse. These results establish a valuable model for future studies of the biochemical basis of neuropathic pain in mice with specific gene modifications.

In the central nervous system (CNS), dopamine is involved in the control of locomotion, cognition, affect and neuroendocrine secretion. These actions of dopamine are mediated by five different receptor subtypes, which are members of the large G-protein coupled receptor superfamily. The dopamine receptor subtypes are divided into two major subclasses: the D1-like and D2-like receptors, which typically couple to Gs and Gj mediated transduction systems. In the CNS, the various receptor subtypes display specific anatomical distributions, with D1-like receptors being mainly post-synaptic and D2-like receptors being both pre- and post-synaptic. D1 and D2 dopamine receptors, the most abundant subtypes in the CNS, appear to be expressed largely in distinct neurons. Substance P and dynorphin, which are expressed in D1 receptor-containing neurons, as well as pre-proenkephalin in D2 receptor-containing neurons, have been used as monitors of dopaminergic activity in the CNS. Expression of immediate early genes, in particular fos, has also been found to correlate with dopaminergic transmission. Dopamine released from the hypothalamus controls the synthesis and secretion of prolactin from the anterior pituitary via D2 dopamine receptors. As yet none of the dopamine receptor subtypes have been associated with the etiology of psychotic disorders, such as schizophrenia. However, the recent characterization of D3 and D4 receptors which are, interestingly, expressed in areas of the CNS mediating cognition and affect or showing increased affinity for certain neuroleptics, have renewed the interest and hope of finding effective neuroleptics devoid of side effects. Finally, the recent production of genetically-derived animals lacking several of these receptor genes should help elucidate which specific physiological paradigms the receptors mediate.

Tachykinin NK1 receptor antagonists have failed to exhibit efficacy in clinical trials of a variety of clinical pain states. By contrast, in preclinical studies in animals NK1 receptor antagonists have been shown to attenuate nociceptive responses sensitized by inflammation or nerve damage, although they exhibit little effect on baseline nociception. Other agents with this profile of activity in animal tests, typically nonsteroidal anti-inflammatory drugs (NSAIDs), are analgesic in humans. Thus, NK1 receptor antagonists appear able to block behavioural responses to noxious and other stressful sensory stimuli at a level detectable in animal tests but fail to provide the level of sensory blockade required to produce clinical analgesia in humans.

OBJECTIVE

Modafinil was tested for efficacy in facilitating abstinence in cocaine-dependent patients, compared to placebo.

METHODS

This was a double-blind placebo-controlled study, with 12 weeks of treatment and a 4-week follow-up. Six outpatient substance abuse treatment clinics participated in the study. There were 210 treatment-seekers randomized, having a diagnosis of cocaine dependence; 72 participants were randomized to placebo, 69 to modafinil 200mg, and 69 to modafinil 400mg, taken once daily on awakening. Participants came to the clinic three times per week for assessments and urine drug screens, and had one hour of individual psychotherapy weekly. The primary outcome measure was the weekly percentage of cocaine non-use days.

RESULTS

The GEE regression analysis showed that for the total sample, there was no significant difference between either modafinil group and placebo in the change in average weekly percent of cocaine non-use days over the 12-week treatment period (p>0.79). However, two secondary outcomes showed significant effects by modafinil 200mg: the maximum number of consecutive non-use days for cocaine (p=0.02), and a reduction in craving (p=0.04). Also, a post hoc analysis showed a significant effect of modafinil that increased the weekly percentage of non-use days in the subgroup of those cocaine patients who did not have a history of alcohol dependence (p<0.02).

CONCLUSIONS

These data suggest that modafinil, in combination with individual behavioral therapy, was effective for increasing cocaine non-use days in participants without co-morbid alcohol dependence, and in reducing cocaine craving.

Pregabalin is a new synthetic molecule and a structural derivative of the inhibitory neurotransmitter gamma-aminobutyric acid. It is an alpha2-delta (alpha2-delta) ligand that has analgesic, anticonvulsant, anxiolytic, and sleep-modulating activities. Pregabalin binds potently to the alpha2-delta subunit of calcium channels, resulting in a reduction in the release of several neurotransmitters, including glutamate, noradrenaline, serotonin, dopamine, and substance P. In this review, I will discuss the pharmacology of pregabalin and available efficacy studies in pain management. This review will focus on the advances in pregabalin pharmacology since my previous review in 2005.

Our intent in this review was to consider the relationship between the biophysical properties of motoneurons and the mechanisms by which they transduce the synaptic inputs they receive into changes in their firing rates. Our emphasis has been on experimental results obtained over the past twenty years, which have shown that motoneurons are just as complex and interesting as other central neurons. This work has shown that motoneurons are endowed with a rich complement of active dendritic conductances, and flexible control of both somatic and dendritic channels by endogenous neuromodulators. Although this new information requires some revision of the simple view of motoneuron input-output properties that was prevalent in the early 1980's (see sections 2.3 and 2.10), the basic aspects of synaptic transduction by motoneurons can still be captured by a relatively simple input-output model (see section 2.3, equations 1-3). It remains valid to describe motoneuron recruitment as a product of the total synaptic current delivered to the soma, the effective input resistance of the motoneuron and the somatic voltage threshold for spike initiation (equations 1 and 2). However, because of the presence of active channels activated in the subthreshold range, both the delivery of synaptic current and the effective input resistance depend upon membrane potential. In addition, activation of metabotropic receptors by achetylcholine, glutamate, noradrenaline, serotonin, substance P and thyrotropin releasing factor (TRH) can alter the properties of various voltage- and calcium-sensitive channels and thereby affect synaptic current delivery and input resistance. Once motoneurons are activated, their steady-state rate of repetitive discharge is linearly related to the amount of injected or synaptic current reaching the soma (equation 3). However, the slope of this relation, the minimum discharge rate and the threshold current for repetitive discharge are all subject to neuromodulatory control. There are still a number of unresolved issues concerning the control of motoneuron discharge by synaptic inputs. Under dynamic conditions, when synaptic input is rapidly changing, time- and activity-dependent changes in the state of ionic channels will alter both synaptic current delivery to the spike-generating conductances and the relation between synaptic current and discharge rate. There is at present no general quantitative expression for motoneuron input-output properties under dynamic conditions. Even under steady-state conditions, the biophysical mechanisms underlying the transfer of synaptic current from the dendrites to the soma are not well understood, due to the paucity of direct recordings from motoneuron dendrites. It seems likely that resolving these important issues will keep motoneuron afficiandoes well occupied during the next twenty years.

BACKGROUND

Blood for transfusion is stored for up to 42 days. Older blood develops lesions and accumulates potentially injurious substances. Some studies report increasing toxicity as blood ages. We assessed the safety of transfused older versus newer stored blood.

METHODS

PubMed, Scopus, and Embase were searched using terms new and old and red blood cell and storage through May 6, 2011, for observational and randomized controlled studies comparing outcomes using transfused blood having longer and shorter storage times. Death was the outcome of interest.

RESULTS

Twenty-one studies were identified, predominantly in cardiac surgery (n=6) and trauma (n=6) patients, including 409,966 patients. A test for heterogeneity of these studies' results was not significant for mortality (I(2)=3.7%, p=0.41). Older blood was associated with a significantly increased risk of death (odds ratio, 1.16; 95% confidence interval [CI], 1.07-1.24). Using available mortality data, 97 (95% CI, 63-199) patients need to be treated with only new blood to save one life. Subgroup analysis of these trials indicated that the increased risk was not restricted to a particular type of patient, size of trial, or amount of blood transfused.

CONCLUSIONS

Based on available data, use of older stored blood is associated with a significantly increased risk of death.

The development of light-emitting diodes with improved efficiency, spectral properties, compactness and integrability is important for lighting, display, optical interconnect, logic and sensor applications. Monolayer transition-metal dichalcogenides have recently emerged as interesting candidates for optoelectronic applications due to their unique optical properties. Electroluminescence has already been observed from monolayer MoS2 devices. However, the electroluminescence efficiency was low and the linewidth broad due both to the poor optical quality of the MoS2 and to ineffective contacts. Here, we report electroluminescence from lateral p-n junctions in monolayer WSe2 induced electrostatically using a thin boron nitride support as a dielectric layer with multiple metal gates beneath. This structure allows effective injection of electrons and holes, and, combined with the high optical quality of WSe2, yields bright electroluminescence with 1,000 times smaller injection current and 10 times smaller linewidth than in MoS2 (refs 17,18). Furthermore, by increasing the injection bias we can tune the electroluminescence between regimes of impurity-bound, charged and neutral excitons. This system has the required ingredients for new types of optoelectronic device, such as spin- and valley-polarized light-emitting diodes, on-chip lasers and two-dimensional electro-optic modulators.

Pain is a sensation we have all experienced. For most of us, the pain has been temporary. However, for patients with pathological pain, the pain experience is unending, with little hope for therapeutic relief. Pathological pain is characterized by an amplified response to normally innocuous stimuli, and an amplified response to acute pain. Pathological pain has long been described as the result of dysfunctional neuronal activity. While neuronal functioning is indeed altered, there is significant evidence showing that exaggerated pain is regulated by the activation of astrocytes and microglia. In exaggerated pain, astrocytes, and microglia are activated by neuronal signals including substance P, glutamate, and fractalkine. Activation of glia by these substances leads to the release of mediators that then act on other glia and neurons. These include a family of proteins called "proinflammatory cytokines" released from microglia and astrocytes. These cytokines have been shown to be critical mediators of exaggerated pain. Some patients with pathological pain also report "extra-territorial" and/or "mirror" image pain. That is, exaggerated pain is experienced not only in the area of trauma. In extra-territorial pain, pain is also perceived as arising from neighboring healthy tissues outside of the site of trauma. In the rare cases of mirror-image pain, such pain is perceived as arising from the healthy, corresponding body part on the opposite side of the body. New data suggest that activation of astrocyte communication via gap junctions may mediate such spread of pain. While traditional therapies for pathological pain have focused on neuronal targets, the following review describes glia as newly recognized mediators of exaggerated pain, and as new therapeutic targets. Moreover, the glial-neuronal interactions discussed here are likely not exclusive to pain, but rather are likely to play significant roles in other behavioral phenomena.

Several clinical features are consistent with nervous system involvement in the pathogenesis of rheumatoid arthritis. The neuropeptide substance P is one possible mediator of this interaction, since it can be released into joint tissues from primary sensory nerve fibers. The potential effects of the peptide on rheumatoid synoviocytes were examined. The results show that substance P stimulates prostaglandin E2 and collagenase release from synoviocytes. Furthermore, synoviocyte proliferation was increased in the presence of the neuropeptide. Similar effects were observed with a truncated form of substance P. Synoviocytes were sensitive to very small doses of the neuropeptide (10(-9) M), and its effects were inhibited by a specific antagonist. Thus, the specific stimulation of synoviocytes by the neuropeptide substance P represents a pathway by which the nervous system might be directly involved in the pathogenesis of rheumatoid arthritis.

OBJECTIVE

Extracts of St John's wort (Hypericum perforatum) are widely used in the treatment of depression, often as an over-the-counter drug. In contrast to its frequent use, knowledge about the pharmacokinetics of ingredients and drug interactions of St John's wort is poor. We studied the interaction between hypericum extract LI160 and digoxin.

METHODS

The pharmacokinetics of digoxin were investigated in a single-blind, placebo-controlled parallel study. After the achievement of steady state for digoxin on day 5, healthy volunteers received digoxin (0.25 mg/d) either with placebo (n = 12) or with 900 mg/d LI160 (n = 13) for another 10 days. Digoxin concentration profiles on day 5 were compared with day 6 (single-dose interaction) and day 15 (tenth day of co-medication).

RESULTS

There was a highly significant combined-day-and-group effect for digoxin area under the plasma concentration-time curve [AUC(0-24); P = .0001], peak concentration in plasma (Cmax; P = .0001), and plasma drug concentration at the end of a dosing interval (P = .0003) by two-way ANOVA. No statistically significant change was observed after the first dose of hypericum extract [AUC(0-24) at day 6 of 18.1+/-2.9 microg x h/L and 17.7+/-3.0 microg x h/L, mean +/- SD for placebo and hypericum group, respectively]. However, 10 days of treatment with hypericum extract resulted in a decrease of digoxin AUC(0-24) by 25% (day 15, 17.2+/-4.0 microg x h/L and 12.9+/-2.3 microg x h/L; P = .0035). Furthermore, comparison with the parallel placebo group after multiple dosing showed a reduction in trough concentrations and Cmax of 33% (P = .0023) and 26% (P = .0095), respectively. The effect became increasingly pronounced until the tenth day of co-medication.

CONCLUSIONS

As with grapefruit juice, a food product, physicians should also be aware of potential drug-herb interactions. The interaction of St John's wort extract with digoxin kinetics was time dependent. The mechanism involved may be induction of the P-glycoprotein drug transporter.

Ca2+ channels in distinct subcellular compartments of neurons mediate voltage-dependent Ca2+ influx, which integrates synaptic responses, regulates gene expression, and initiates synaptic transmission. Antibodies that specifically recognize the alpha1 subunits of class A, B, C, D, and E Ca2+ channels have been used to investigate the localization of these voltage-gated ion channels on spinal motor neurons, interneurons, and nerve terminals of the adult rat. Class A P/Q-type Ca2+ channels were present mainly in a punctate pattern in nerve terminals located along the cell bodies and dendrites of motor neurons. Both smooth and punctate staining patterns were observed over the surface of the cell bodies and dendrites with antibodies to class B N-type Ca2+ channels, indicating the presence of these channels in the cell surface membrane and in nerve terminals. Class C and D L-type and class E R-type Ca2+ channels were distributed mainly over the cell soma and proximal dendrites. Class A P/Q-type Ca2+ channels were present predominantly in the presynaptic terminals of motor neurons at the neuromuscular junction. Occasional nerve terminals innervating skeletal muscles from the hindlimb were labeled with antibodies against class B N-type Ca2+ channels. Staining of the dorsal laminae of the rat spinal cord revealed a complementary distribution of class A and class B Ca2+ channels in nerve terminals in the deeper versus the superficial laminae. Many of the nerve terminals immunoreactive for class B N-type Ca2+ channels also contained substance P, an important neuropeptide in pain pathways, suggesting that N-type Ca2+ channels are predominant at synapses that carry nociceptive information into the spinal cord.

Associations between stress and health outcomes have now been carefully documented, but the mechanisms by which stress specifically influences disease susceptibility and outcome remain poorly understood. Recent evidence indicates that glucocorticoids (GCs) and catecholamines (CAs), the major stress hormones, inhibit systemically IL-12, TNF-alpha, and INF-gamma, but upregulate IL-10, IL-4, and TGF-beta production. Thus, during an immune and inflammatory response, the activation of the stress system, through induction of a Th2 shift may protect the organism from systemic "overshooting" with T helper lymphocyte 1 (Th1)/proinflammatory cytokines. In certain local responses and under certain conditions, however, stress hormones may actually facilitate inflammation, through induction of IL-1, IL-6, IL-8, IL-18, TNF-alpha, and CRP production, and through activation of the corticotropin-releasing hormone (CRH)/substance P(SP)-histamine axis. Autoimmunity, chronic infections, major depression, and atherosclerosis are characterized by a dysregulation of the pro/anti-inflammatory and Th1/Th2 cytokine balance. Thus, hyperactive or hypoactive stress system, and a dysfunctional neuroendocrine-immune interface associated with abnormalities of the "systemic anti-inflammatory feedback" and/or "hyperactivity" of the local proinflammatory factors may contribute to the pathogenesis of these diseases. Conditions that are associated with significant changes in stress system activity, such as acute or chronic stress, cessation of chronic stress, pregnancy and the postpartum period, or rheumatoid arthritis (RA) through modulation of the systemic or local pro/anti-inflammatory and Th1/Th2 cytokine balance, may suppress or potentiate disease activity and/or progression. Thus, stress hormones-induced inhibition or upregulation of innate and Th cytokine production may represent an important mechanism by which stress affects disease susceptibility, activity, and outcome of various immune-related diseases.

An immunocytochemical analysis with 33 antisera was undertaken to investigate the localization of 25 different neurotransmitter-related antigens in the hypothalamic suprachiasmatic nucleus in the rat. To obtain estimates of relative densities of immunoreactive axons a stereological approach was used involving counting of intersections of immunoreactive axons with a superimposed semi-circle test grid. All neurotransmitter-related antigens found in perikarya within the suprachiasmatic nucleus, including those stained with antisera against bombesin, gastrin-releasing peptide, neurophysin, vasopressin, somatostatin, gamma-aminobutyrate, glutamate decarboxylase and vasoactive intestinal polypeptide were also found in axons within the nucleus. A greater number of these immunoreactive axons was found within the nucleus than in the adjacent anterior hypothalamus. The size of all immunoreactive axons in the suprachiasmatic nucleus was consistently small; immunoreactive axons were found ramifying widely in the nucleus, often ending with terminal boutons near perikarya immunoreactive for the same antigen. All neurotransmitter-related substances found in perikarya of the suprachiasmatic nucleus were also found in axons crossing over the midline to innervate the contralateral nucleus, providing an anatomical substrate for a high degree of communication between the paired nuclei. Axons immunoreactive for other putative transmitters including serotonin arising outside the nucleus were also found in high densities within the nucleus and crossing over the midline between the nuclei. Immunoreactivity for some transmitters was found in axons of similar densities within and outside the nucleus, including antisera against tyrosine hydroxylase; a small number of dopamine beta-hydroxylase and a few phenylethanolamine N-methyltransferase-immunoreactive axons were found in the SCN, suggesting that dopamine, norepinephrine and epinephrine may occur in a limited number of axons in the nucleus. Small numbers of axons immunoreactive with antisera raised against cholecystokinin, prolactin, substance P, thyrotropin-releasing hormone and choline acetyltransferase were found within the suprachiasmatic nucleus. Axons immunoreactive for luteinizing hormone-releasing hormone, adrenocorticotropic hormone, alpha-melanocyte-stimulating hormone and neurotensin were rarely found within the suprachiasmatic nucleus; axons immunoreactive for luteinizing hormone-releasing hormone, adrenocorticotropic hormone, cholecystokinin and tyrosine hydroxylase were found in both horizontal and coronal sections in the area between the left and right suprachiasmatic nuclei.(ABSTRACT TRUNCATED AT 400 WORDS)

Brain-derived neurotrophic factor (BDNF) is synthesized by small neuron cell bodies in the dorsal root ganglia (DRG) and is anterogradely transported to primary afferent terminals in the dorsal horn where it is involved in the modulation of painful stimuli. Here we show that BDNF is released in the rat isolated dorsal horn after chemical stimulation by capsaicin or electrical stimulation of dorsal roots. Capsaicin superfusion (1-100 microm) induced a dose-dependent release of BDNF, measured using ELISA. The highest dose of capsaicin also induced a depletion of BDNF protein in the dorsal horn. BDNF release was also seen after electrical stimulation of the dorsal roots at C-fiber strength. This release was encoded by specific patterns of afferent fiber stimulation. Neither continuous low-frequency (480 pulses, 1 Hz) nor tetanic high-frequency (300 pulses in 3 trains, 100 Hz) stimulation evoked release of BDNF, although substance P (SP) release was observed under both of these conditions. However, BDNF was released after short bursts of high-frequency stimulation (300 pulses in 75 trains, 100 Hz) along with SP and glutamate. The NMDA antagonist d-AP-5 inhibited electrically evoked BDNF release. BDNF release was also measured after systemic or intrathecal NGF treatment. This upregulated BDNF content in the DRG and increased the capsaicin-evoked release of BDNF. Similarly, the amount of BDNF released by burst stimulation was increased after NGF treatment. This activity-dependent release continued to be encoded solely by this stimulation pattern. These experiments demonstrate that BDNF release in the dorsal horn is encoded by specific patterns of afferent fiber stimulation and is mediated by NMDA receptor activation.

1. The relationship between the afferent properties and substance P-like immunoreactivity (SP-LI) of L6 and S1 dorsal root ganglion (DRG) neuronal somata was examined in anaesthetized guinea-pigs. Glass pipette microelectrodes filled with fluorescent dyes were used to make intracellular recordings and to label DRG somata. The dorsal root conduction velocity (CV) and the afferent receptive properties of each unit were categorized according to criteria established in other species. Categories included a variety of low threshold mechanoreceptive classes, innocuous thermoreceptive and several nociceptive classes. Nociceptive units were further subdivided on the basis of CV and the locus of the receptive field (superficial cutaneous, deep cutaneous or subcutaneous). 2. SP-LI was determined using the avidin-biotin complex method and the relative staining intensity determined by image analysis. The possible significance of labelling intensity is discussed. Clear SP-LI appeared in twenty-nine of 117 dye-labelled neurones. All SP-LI positive units with identified receptive properties were nociceptive but not all categories of nociceptors were positive. The intensity of SP-LI labelling varied, often systematically, in relation to afferent properties. There was a tendency for nociceptive neurones with slower CVs and/or smaller cell bodies to show SP-LI. 3. Nineteen of fifty-one C fibre neurones showed SP-LI. Fewer than half the C polymodal nociceptors (CPMs) were positive. The most intensely labelled units were the deep cutaneous nociceptors and some of the CPMs in glabrous skin. C low threshold mechanoreceptors and cooling-sensitive units did not show SP-LI. 4. Ten of sixty-six A fibre neurones exhibited SP-LI, including eight of sixteen A delta nociceptors and two of fifteen A alpha/beta nociceptors. A fibre neurones exhibiting SP-LI included seven of eight deep cutaneous mechanical nociceptors and some superficial cutaneous mechano-heat nociceptors of hairy skin. In contrast, none of twenty superficial cutaneous A high threshold mechanoreceptor units or the thirty-five A fibre low threshold units (D-hair and other units) showed detectable SP-LI. 5. We conclude that SP-LI labelling in guinea-pig DRG neurones is related to (a) afferent receptive properties, (b) the tissue in which the peripheral receptive terminals are located, (c) the CV and (d) the soma size.