BACKGROUND

The amount of allergen necessary to sensitise genetically "at risk" children is unclear. The relation between allergen exposure and asthma is also uncertain.

METHODS

To ensure a wide range of allergen exposures the data from case-control studies of asthma in children aged 12-14 years attending three schools in Los Alamos, New Mexico and Central Virginia were combined. Skin prick tests to indoor and outdoor allergens and bronchial hyperreactivity to histamine were assessed in children with and without symptoms of asthma. The concentration of mite, cat, and cockroach allergens in dust from the children's homes was used as a marker of exposure.

RESULTS

Three hundred and thirty two children (157 with asthmatic symptoms and 175 controls) were investigated. One hundred and eighty three were classified as atopic on the basis of allergen skin prick tests and 68 as asthmatic (symptoms plus bronchial responsiveness). The prevalence and degree of sensitisation to mite and cockroach, but not cat, was strongly associated in atopic children with increasing domestic concentrations of these allergens. Asthma was strongly associated with sensitisation to indoor allergens (p<10(-6)) and weakly to outdoor allergens (p = 0.026). There was an association between current asthma and the concentration of mite allergen amongst atopic children (p = 0.008) but not amongst those who were specifically mite sensitised (p = 0.16).

CONCLUSIONS

The domestic reservoir concentration of mite and cockroach, but not cat, allergen was closely related to the prevalence of sensitisation in atopic children. However, the prevalence of current asthma had a limited relationship to these allergen measurements, suggesting that other factors play a major part in determining which allergic individuals develop asthma.

We have shown that the 12/15-lipoxygenase (12/15-LO) product 12S-hydroxyeicosatetraenoic acid increases monocyte adhesion to human endothelial cells (EC) in vitro. Recent studies have implicated 12/15-LO in mediating atherosclerosis in mice. We generated transgenic mice on a C57BL/6J (B6) background that modestly overexpressed the murine 12/15-LO gene (designated LOTG). LOTG mice had 2.5-fold elevations in levels of 12S-hydroxyeicosatetraenoic acid and a 2-fold increase in expression of 12/15-LO protein in vivo. These mice developed spontaneous aortic fatty streak lesions on a chow diet. Thus, we examined effects of 12/15-LO expression on early events leading to atherosclerosis in these mice. We found that, under basal unstimulated conditions, LOTG EC bound more monocytes than B6 control EC (18 +/- 2 versus 7 +/- 1 monocytes/field, respectively; p < 0.0001). Inhibition of 12/15-LO activity in LOTG EC using a 12/15-LO ribozyme completely blocked monocyte adhesion in LOTG mice. Thus, 12/15-LO activity is required for monocyte/EC adhesion in the vessel wall. Expression of ICAM-1 in aortic endothelia of LOTG mice was increased severalfold. VCAM-1 expression was not changed. In a series of blocking studies, antibodies to alpha(4) and beta(2) integrins in WEHI monocytes blocked monocyte adhesion to both LOTG and B6 control EC. Inhibition of ICAM-1, VCAM-1, and connecting segment-1 fibronectin in EC significantly reduced adhesion of WEHI monocytes to LOTG EC. In summary, these data indicate that EC from LOTG mice are "pre-activated" to bind monocytes. Monocyte adhesion in LOTG mice is mediated through beta(2) integrin and ICAM-1 interactions as well as through VLA-4 and connecting segment-1 fibronectin/VCAM-1 interactions. Thus, 12/15-LO mediates monocyte/EC interactions in the vessel wall in atherogenesis at least in part through molecular regulation of expression of endothelial adhesion molecules.

BACKGROUND

Our objective was to identify the allergens associated with asthma among schoolchildren in an area of the United States where dust mite growth is expected to be poor. Los Alamos, N.M., was chosen because it has low rainfall and is at high altitude (7200 feet) making it very dry. One hundred eleven children (12 to 14 years old) from the middle school who had been previously classified according to bronchial hyperreactivity to histamine (BHR) were studied.

METHODS

Sera were assayed for IgE antibodies to mite, cat, dog, cockroach, Russian thistle, and grass pollen, with both CAP system fluoroimmunoassay (Kabi Pharmacia, Uppsala, Sweden) and conventional RAST. Allergens were measured in dust samples from 108 homes with two-site assays for mite (Der p 1 and Der f 1), cat (Fel d 1), dog (Can f 1), and cockroach (Bla g 2).

RESULTS

Concentrations of dog and cat allergens were elevated in almost all houses with pets but were also high in a significant proportion of the houses without pets. Levels of mite allergen were less than 2 micrograms/gm in 95% of the houses, and cockroach was undetectable in all but two of the houses. Among the 21 with BHR who had symptoms, 67% had IgE antibody to dog and 62% had IgE antibody to cat. For these allergens IgE antibody was strongly associated with asthma (p < 0.001). By contrast, the presence of IgE antibody to mite, cockroach, or grass pollen was not significantly associated with asthma.

CONCLUSIONS

The high prevalence of IgE antibody to cat and dog allergens among these children is in keeping with the presence of cat and/or dog allergen in most of the houses. Furthermore, sensitization (as judged by IgE antibodies) to cat and dog allergens was strongly associated with asthma. On the other hand, no clear relationship was found between sensitization or symptoms and the current level of allergen in individual houses. The results show that in this mite-and cockroach-free environment sensitization to domestic animals was the most significant association with asthma.

Plasmacytoid dendritic cells (pDCs) competent to make type I interferon were rigorously defined as a Ly-6C(+) and CD11c(Lo) subset of the B220(+)CD19(-) CD43(+)CD24(Lo) bone marrow (BM) Fraction A. Otherwise similar Ly6C(-) cells expressed the natural killer (NK) markers DX5 and NK1.1. pDCs represented a stable, discrete, and long-lived population. Stem cells and early lymphoid progenitors (ELPs), but not prolymphocytes, were effective precursors of pDCs, and their differentiation was blocked by ligation of Notch receptors. Furthermore, pDCs were present in the BM of RAG1(-/-), CD127/IL-7Ra(-/-), and Pax5(-/-) mice. pDCs in RAG1/GFP knock-in mice could be subdivided, and immunoglobulin D(H)-J(H) rearrangements, as well as transcripts for the B-lineage-related genes Pax5, mb1/CD79a, ebf, and Bcl11a, were identified only in the green fluorescent protein-positive (GFP(+)) pDC1 subset. All pDCs expressed terminal deoxynucleotidyl transferase (TdT), the ETS transcription factor Spi-B, the nuclear factor-kappaB transcription factor RelB, toll-like receptor 9 (TLR9), and interferon consensus sequence binding protein (ICSBP)/interferon regulatory factor 8 (IRF-8) transcripts; lacked CD16 and granulocyte colony-stimulating factor receptor (G-CSFR); and were uniformly interleukin-7 receptor alpha (IL-7Ralpha(-)) AA4.1(Lo), CD27(-), Flk-2(Lo), c-Kit(-), DX-5(-), and CD11b(-), while CD4 and CD8alpha were variable. GFP(+) pDC1 subset was less potent than GFP(-) pDC2s in T allostimulation and production of tumor necrosis factor alpha (TNFalpha), interferon alpha (IFNalpha), and interleukin-6 (IL-6), while only pDC2s made IFNgamma and IL-12 p70. Thus, 2 functionally specialized subsets of pDCs arise in bone marrow from progenitors that diverge from B, T, and NK lineages at an early stage.

Infection with Helicobacter pylori (H. pylori), especially CagA+ strains, has been associated with an increased risk of noncardia gastric adenocarcinoma. The relationship with junctional cancer (adenocarcinomas of the esophagus and gastric cardia combined) has not been adequately investigated, although some studies have reported a reduced risk associated with H. pylori and CagA seroseropositivity. We investigated this question in a subset of cases and controls from a recently completed, large population-based case-control study of gastric and esophageal adenocarcinomas in Los Angeles County. Using established antigen-specific ELISAs, serum IgG antibodies to H. pylori whole-cell antigens (Helico-G) and CagA were measured in population controls (n = 356) and patients with incident esophageal adenocarcinoma (n = 80), gastric cardia cancer (n = 87) or distal gastric cancers (noncardia gastric adenocarcinoma) (n = 127). After controlling for demographic characteristics (age, gender, race, birthplace, education), smoking and body mass index, seropositivity for H. pylori was associated with a statistically significant increased risk of distal gastric cancer (adjusted odds ratio [OR] = 1.85, 95% confidence interval [CI] = 1.03, 3.32) but the risk of junctional cancer was not increased (adjusted OR = 1.26, 95% CI = 0.82, 1.94). The risk of junctional cancer was not changed when CagA and H. pylori were both considered, but the risk of distal gastric cancer was further increased. Subjects who were seropositive for both CagA and H. pylori compared to those who were seronegative for H. pylori showed a risk of 2.20 (95% CI = 1.13, 4.26) for distal gastric cancer and 0.86 (95% CI = 0.47, 1.59) for junctional cancer. Although tests for interaction between smoking and H. pylori were not statistically significant for junctional or distal gastric cancers, risk for both tumor types tended to be higher among current smokers who were also H. pylori seropositive. In conclusion, we find no evidence that infection with CagA+ strains of H. pylori reduces risk of esophageal and gastric cardia adenocarcinoma in this population. Our findings confirm the positive association between risk of distal gastric cancer and infection with H. pylori infection, especially CagA+ strains.

Utilization of general medical and mental health services by respondents in the Los Angeles Epidemiologic Catchment Area (ECA) site was compared with that in three ECA sites studied previously (New Haven, Conn, Baltimore, and St Louis). Within the Los Angeles sample, Mexican-American patterns of utilization were compared with those for non-Hispanic whites. Los Angeles respondents were less likely than those at other ECA sites to make ambulatory health care visits and to be hospitalized for physical or mental health reasons. Mexican Americans were less likely than non-Hispanic whites to report ambulatory health care but were as likely to have been hospitalized. Six percent of Los Angeles respondents reported a recent mental-health-care visit as compared with 6% to 7% of respondents at the other ECA sites. However, among respondents with Diagnostic Interview Schedule DSM-III disorders diagnosed within the six months prior to the interview, a lower proportion made a mental health visit in Los Angeles (14%) compared with the other sites (16% to 20%). Of those who made a mental-health-care visit, Los Angeles respondents with a recently diagnosed disorder were more likely than comparable respondents at the other ECA sites to visit a mental health specialist rather than a general medical care provider. Mexican Americans with a recently diagnosed mental disorder were only half as likely as non-Hispanic whites (11% vs 22%, respectively) to have made a mental health visit. However, when Mexican Americans with Diagnostic Interview Schedule/DSM-III did make a mental health visit, they were as likely as non-Hispanic whites to see a mental health specialist.

OBJECTIVE

Cervical spine (C-spine) injuries occur infrequently in children but may be associated with significant disability and mortality. The purpose of this study was to review the experience of a level 1 pediatric trauma center to determine the epidemiology, risk factors, mechanisms, levels, types of injury, comorbid factors, and outcomes associated with these potentially devastating injuries.

METHODS

A retrospective analysis of 103 consecutive C-spine injuries treated at a level 1 pediatric trauma center over a 9(1/2)-year period (January 1991 through August 2000) was performed.

RESULTS

The mean age was 10.3 +/- 5.2 years, and the male-to-female ratio was 1.6:1. The most common mechanism of injury was motor vehicle related (52%), followed by sporting injuries (27%). Football injuries accounted for 29% of all sports-related injuries. Sixty-eight percent of all children sustained injuries to C1 to C4; 25% to C5 to C7; and 7% to both. Spinal cord injury without radiographic abnormality (SCIWORA) occurred in 38%. Five patients had complete cord lesions involving the lower C-spine (C4 to C7); 4 of these were motor vehicle related, and all 4 patients died. Isolated C-spine injuries occurred in 43%, whereas 38% had associated closed head injuries (CHI). The overall mortality rate was 18.5%, most commonly motor vehicle related (95%), occurring in younger children (mean and median age 5 years) and associated with upper C-spine injuries (74%) and CHI (89%). C1 dislocations occurred in younger children (mean age, 6.6 years), most often as a result of motor vehicle-related trauma (especially pedestrians) and were associated with the highest injury severity score (ISS), longest length of stay (LOS), most CHIs, and the highest mortality rate (50%). C-spine fractures with or without SCI occurred most commonly as a result of falls and dives. Sporting injuries occurred almost exclusively in adolescent boys (mean age, 13.8 years) and were isolated injuries associated with a relatively low ISS and shorter LOS. Interestingly, 75% of sporting injuries showed SCIWORA, and all infants suffering from child abuse had SCIWORA.

CONCLUSIONS

Mechanisms of injury are age related, with younger children sustaining C-spine injuries as a result of motor vehicle-related trauma and older adolescents commonly injured during sporting activities. C-spine injuries in children most commonly involve the upper C-spine, but complete lesions of the cord are associated more frequently with lower C-spine injuries. The type of C-spine injury is related to the mechanism of injury: SCIWORA is associated with sporting activities and child abuse, C-spine dislocations most commonly result from motor vehicle-related trauma (especially among pedestrians), and C-spine fractures occur most commonly as a result of falls and dives. Predictors of mortality include younger age, motor vehicle-related mechanism, C1 dislocations, high ISS greater than 25, and associated CHI. A high index of suspicion for SCIWORA is essential when evaluating adolescents with neck trauma associated with sporting injuries or victims of child abuse.

Neisseria gonorrhoeae and Neisseria meningitidis have evolved intricate mechanisms to evade complement-mediated killing. Sialylation of gonococcal lipooligosaccharide (LOS) results in conversion of previously serum sensitive strains to unstable serum resistance, which is mediated by factor H binding. Porin (Por) is also instrumental in mediating stable serum resistance in gonococci. The 5th loop of certain gonococcal PorlAs binds factor H, which efficiently inactivates C3b to iC3b. Factor H glycan residues may be essential for factor H binding to certain Por1A strains. Por1A strains can also regulate the classical pathway by binding to C4b-binding protein (C4bp) probably via the 1st loop of the Por molecule. Certain serum resistant Por1 B strains can also regulate complement by binding C4bp through a loop other than loop 1. Purified C4b can inhibit binding of C4bp to Por 1B, but not Por1A, suggesting different binding sites on C4bp for the two Por types. Unlike serum resistant gonococci, resistant meningococci have abundant C3b on their surface, which is only partially processed to iC3b. The main mechanism of complement evasion by group B meningococci is inhibition of membrane attack complex (MAC) insertion by their polysaccharide capsule. LOS structure may act in concert with capsule to prevent MAC insertion. Meningococcal strains with Class 3 Por preferentially bind factor H, suggesting Class 3 Por acts as a receptor for factor H.

OBJECTIVE

We created an evidence based postoperative surveillance protocol for patients with localized and locally advanced renal cell carcinoma (RCC) based on a risk group stratification system.

METHODS

559 patients undergoing surgery for localized and ocally advanced RCC were stratified into low risk (LR), intermediate risk (IR) and high risk (HR) groups based on the University of California-Los Angeles Integrated Staging System (UISS). Tumor recurrences were identified and categorized according to time and location.

RESULTS

Patients with localized disease had a lower 5-year recurrence rate than patients with locally advanced (nodal) disease (27.6% vs 64%, p <0.0001). Patients in the LR, IR, and HR groups following nephrectomy demonstrated 5-year recurrence-free rates of 90.4%, 61.8%, and 41.9%, respectively (p <0.0001), and median times to recurrence of 28.9, 17.8 and 9.5 months, respectively (p <0.0001). Chest and abdomen recurrences comprised of 75% and 37.5%, 77.4% and 58.1%, and 45.2% and 67.7% of recurrences in the LR, IR and HR groups, respectively. In patients with node positive disease, chest and abdomen comprised of 58.8% and 76.5% of recurrences, respectively. Patients undergoing partial nephrectomy did not demonstrate a greater rate of local or distant recurrence compared with patients undergoing radical nephrectomy.

CONCLUSIONS

Significant differences in incidence and time to recurrence following surgical resection for RCC mandates unique surveillance protocols for patients in each of the UISS risk groups. LR group patients should be followed for at least 5 years, whereas IR and HR group patients require longer surveillance. HR group patients require more stringent abdominal surveillance, whereas LR group patients should emphasize the chest. Patients with nodal disease also require stringent followup. Patients undergoing partial nephrectomy for localized disease can be followed according to the same UISS risk group based protocol.

Among men who have sex with men (MSM) in Los Angeles County, methamphetamine use is associated with high rates of HIV prevalence and sexual risk behaviors. In four separate samples of MSM who differed in the range of their intensity of methamphetamine use, from levels of recreational use to chronic use to those for MSM seeking drug abuse treatment, the association between methamphetamine use and HIV infection increased as the intensity of use increased. The lowest HIV prevalence rate (23%) was observed among MSM contacted through street outreach who mentioned recent methamphetamine use, followed by MSM who used at least once a month for six months (42%), followed by MSM seeking intensive outpatient treatment (61%). The highest rate (86%) was observed among MSM seeking residential treatment for methamphetamine dependence. The interleaving nature of these epidemics calls for comprehensive strategies that address methamphetamine use and concomitant sexual behaviors that increase risk of HIV transmission in this group already at high risk. These and other data suggest that MSM who infrequently use methamphetamine may respond to lower intensity/lower cost prevention and early intervention programs while those who use the drug at dependence levels may benefit from high intensity treatment to achieve goals of reduced drug use and HIV-risk sexual behaviors.

BACKGROUND

The objective of the current study was to compare, in a large multicenter study, the discriminating accuracy of four prognostic models developed to predict the survival of patients undergoing nephrectomy for nonmetastatic renal cell carcinoma (RCC).

METHODS

A total of 2404 records of patients from 6 European centers were retrospectively reviewed. For each patient, prognostic scores were calculated according to four models: the Kattan model, the University of California at Los Angeles integrated staging system (UISS) model, the Yaycioglu model, and the Cindolo model. Survival curves were estimated by the Kaplan-Meier method and compared by the log-rank test. Discriminating ability was assessed by the Harrell c-index for censored data. The primary end point was overall survival (OS), and the secondary end points were cancer-specific survival (CSS) and disease recurrence-free survival (RFS).

RESULTS

At last follow-up, 541 subjects had died of any causes, with a 5-year OS rate of 80%. The 5-year CSS and RFS rates were 85% and 78%, respectively. All models discriminated well (P < 0.0001). The c-indexes for OS were 0.706 for the Kattan nomogram, 0.683 for the UISS model, and 0.589 and 0.615 for the Yaycioglu and Cindolo models, respectively. The Kattan nomogram was found to improve discrimination substantially in the UISS intermediate-risk patients.

CONCLUSIONS

The current study appears to better define the general applicability of prognostic models for predicting survival in patients with nonmetastatic RCC treated with nephrectomy. The results suggest that postoperative models discriminate substantially better than preoperative ones. The Kattan model was consistently found to be the most accurate, although the UISS model was only slightly less well performing. The Kattan model can be useful in the UISS intermediate-risk patients.

There is substantial in vitro and in vivo evidence implicating tea polyphenols as chemopreventive agents against various cancers. In a case-control study conducted among Asian-American women in Los Angeles County, we reported a significant inverse relationship between intake of green tea and risk of breast cancer (A. H. Wu et al., Int. J. Cancer, 106: 574-579, 2003). Because catechol-containing tea polyphenols are very rapidly O-methylated by human catechol-O-methyltransferase (COMT), we are interested in determining whether the association between tea intake and breast cancer differed in women according to COMT genotype. We examined the interrelationships between tea intake, COMT genotype, and breast cancer risk in 589 incident cases and 563 population-based controls from a population-based case-control study of breast cancer in Chinese-, Japanese-, and Filipino-American women in Los Angeles County. Risk of breast cancer was influenced significantly by intake of tea, particularly green tea intake. However, the inverse association between tea intake and breast cancer risk was observed only among individuals who possessed at least one low-activity COMT allele. Among women who carried at least one low activity COMT allele, tea drinkers showed a significantly reduced risk of breast cancer (adjusted odds ratio, 0.48; 95% confidence interval, 0.29-0.77) compared with nontea drinkers after adjustment for relevant demographic, menstrual, reproductive, and dietary factors. This risk reduction was observed in relation to both green tea and black tea intake. In contrast, risk of breast cancer did not differ between tea drinkers and nontea drinkers among those who were homozygous for the high activity COMT allele (adjusted odds ratio, 1.02; 95% confidence interval, 0.66-1.60). In conclusion, tea catechins appeared to reduce breast cancer risk in this study of Asian-American women. Reduction in risk was strongest among persons who had the low activity COMT alleles, suggesting these individuals were less efficient in eliminating tea catechins and may derive the most benefit from these compounds.

We have applied two strategies for the cloning of four genes responsible for the biosynthesis of the GT1a ganglioside mimic in the lipooligosaccharide (LOS) of a bacterial pathogen, Campylobacter jejuni OH4384, which has been associated with Guillain-Barré syndrome. We first cloned a gene encoding an alpha-2, 3-sialyltransferase (cst-I) using an activity screening strategy. We then used nucleotide sequence information from the recently completed sequence from C. jejuni NCTC 11168 to amplify a region involved in LOS biosynthesis from C. jejuni OH4384. The LOS biosynthesis locus from C. jejuni OH4384 is 11.47 kilobase pairs and encodes 13 partial or complete open reading frames, while the corresponding locus in C. jejuni NCTC 11168 spans 13.49 kilobase pairs and contains 15 open reading frames, indicating a different organization between these two strains. Potential glycosyltransferase genes were cloned individually, expressed in Escherichia coli, and assayed using synthetic fluorescent oligosaccharides as acceptors. We identified genes encoding a beta-1, 4-N-acetylgalactosaminyl-transferase (cgtA), a beta-1, 3-galactosyltransferase (cgtB), and a bifunctional sialyltransferase (cst-II), which transfers sialic acid to O-3 of galactose and to O-8 of a sialic acid that is linked alpha-2,3- to a galactose. The linkage specificity of each identified glycosyltransferase was confirmed by NMR analysis at 600 MHz on nanomole amounts of model compounds synthesized in vitro. Using a gradient inverse broadband nano-NMR probe, sequence information could be obtained by detection of (3)J(C,H) correlations across the glycosidic bond. The role of cgtA and cst-II in the synthesis of the GT1a mimic in C. jejuni OH4384 were confirmed by comparing their sequence and activity with corresponding homologues in two related C. jejuni strains that express shorter ganglioside mimics in their LOS.

BACKGROUND

Although political violence continues in parts of Central America, South America, and Mexico, little is known about its relationship to the health of Latino immigrants living in the United States.

OBJECTIVE

To determine (1) rates of exposure to political violence among Latino adult primary care patients who have immigrated to the United States from Central America, South America, and Mexico and its impact on mental health and health-related quality of life and (2) frequency of disclosure of political violence to primary care clinicians.

METHODS

Two-stage cluster design survey of a systematic sample of Latino immigrant adults in 3 community-based primary care clinics in Los Angeles, conducted from July 2001 to February 2002.

METHODS

Reports of exposure to political violence in home country before immigrating to the United States and communication with clinicians about political violence; self-reported measures of health-related quality of life using the Medical Outcomes Study Short Form 36 (MOS SF-36); symptoms of depression, anxiety, and alcohol disorders using the Primary Care Evaluation of Mental Disorders (PRIME-MD); and symptoms of posttraumatic stress disorder (PTSD) using the PTSD Checklist-Civilian Version (PCL-C).

RESULTS

A total of 638 (69%) of 919 eligible patients participated. The nonresponse rates did not differ by age, sex, recruitment sites, or clinic sessions. In weighted analyses, 54% of participants reported political violence experiences in their home countries, including 8% who reported torture. Of those exposed to political violence, 36% had symptoms of depression and 18% had symptoms of PTSD vs 20% and 8%, respectively, among those not exposed to political violence. Controlling for age, sex, country, years lived in the United States, acculturation, income, health insurance status, and recruitment site in a subsample of 512 participants (56%), those who reported political violence exposure were more likely to meet symptom criteria for PTSD (adjusted odds ratio [AOR], 3.4; 95% confidence interval [CI], 1.4-8.4) and to have symptoms of depression (AOR, 2.8; 95% CI, 1.4-5.4) and symptoms of panic disorder (AOR, 4.8; 95% CI, 1.6-14.4) than participants not reporting political violence. Those exposed to political violence reported more chronic pain and role limitations due to physical problems, as well as worse physical functioning and lower perceptions of general health than those who were not exposed to political violence. Only 3% of the 267 patients who had experienced political violence reported ever telling a clinician about it after immigrating; none reported their current physician asking about political violence.

CONCLUSIONS

Latino immigrants in primary care in Los Angeles have a high prevalence of exposure to political violence before immigrating to the United States and associated impairments in mental health and health-related quality of life.

This study examined the HIV risk behaviors and life experiences of 151 transgender female youth, ages 15-24, in Los Angeles and Chicago. Descriptive analyses and logistic regression modeling were used to identify life factors associated with ever having engaged in sex work. Sixty-seven percent of participants had ever engaged in sex work and 19% self-reported being HIV positive. Many factors were significantly associated with sex work for this sample population. A final multivariate logistic regression model found that lower education status, homelessness, use of street drugs, and perceived social support remained significantly associated with sex work when controlling for other factors. Findings highlight the complex HIV risk environment and suggest a need for sex work initiation research for transgender female youth. HIV prevention efforts for this population need to include broad-based approaches that take into account individual, social, and community-level factors relevant to the lives of transgender female youth.

Non-typeable Haemophilus influenzae (NTHi) invades host cells by binding of the platelet-activating factor (PAF) receptor via lipooligosaccharide (LOS) glycoforms containing phosphorylcholine (ChoP). The effect of NTHi infection on host cell signalling and its role in NTHi invasion was examined. The infection of human bronchial epithelial cells with NTHi 2019 increased cytosolic Ca2+ levels, and the invasion of bronchial cells by NTHi 2019 was inhibited by pretreatment with the cell-permeant intracellular Ca2+ chelator BAPTA-AM (P = 0.022) or thapsigargin (P = 0.016). Cytosolic inositol phosphate (IP) levels were also increased after infection with NTHi 2019 (P < 0.001), but not after infection with isogenic mutants expressing altered LOS glycoforms lacking ChoP. PAF receptor antagonist reduced NTHi 2019-stimulated IP production in a dose-dependent manner. NTHi 2019 invasion was inhibited by pertussis toxin (PTX) and the phosphatidylinositol-3-kinase inhibitors wortmannin and LY294002. The less invasive strain NTHi 7502 also initiated IP production, but was unaffected by PAF receptor antagonist or PTX. These data demonstrate that the binding of the PAF receptor by NTHi initiates receptor coupling to a PTX-sensitive heterotrimeric G protein complex, resulting in a multifactorial host cell signal cascade and bacterial invasion. Moreover, the data suggest that NTHi strains initiate cell signalling and invade by different mechanisms, and that invasion mediated by PAF receptor activation is more efficient than macropinocytosis.

BACKGROUND

Inflammation is increasingly recognized as an important contributing factor in diabetes mellitus. Lipoxygenases (LOs) produce active lipids that promote inflammatory damage by catalyzing the oxidation of linoleic and arachidonic acid, and LO is expressed in rodent and human islets. Little is known about the differential effect of the various hydroxyeicosatetraenoic acids (HETEs) that result from LO activity in human islets.

OBJECTIVE

We compared the effects of 12-LO products on human islet viability and function.

METHODS

Human islets were treated with stable compounds derived from LOs: 12(S)-HETE, 15HETE, 12HPETE, and 12RHETE and then examined for insulin secretion and islet viability. The p38-MAPK (p38) and JNK stress-activated pathways were investigated as mechanisms of 12-LO-mediated islet inhibition in rodent and human islets.

RESULTS

Insulin secretion was consistently reduced by 12(S)-HETE and 12HPETE. 12(S)-HETE at 1 nm reduced viability activity by 32% measured by MTT assay and increased cell death by 50% at 100 nm in human islets. These effects were partially reversed with lisofylline, a small-molecule antiinflammatory compound that protects mitochondrial function. 12(S)-HETE increased phosphorylated p38-MAPK (pp38) protein activity in human islets. Injecting 12-LO siRNA into C57BL/6 mice reduced 12-LO and pp38-MAPK protein levels in mouse islets. The addition of proinflammatory cytokines increased pp38 levels in normal mouse islets but not in siRNA-treated islets.

CONCLUSIONS

These data suggest that 12(S)-HETE reduces insulin secretion and increases cell death in human islets. The 12-LO pathway is present in human islets, and expression is up-regulated by inflammatory cytokines. Reduction of 12-LO activity could thus provide a new therapeutic approach to protect human beta-cells from inflammatory injury.

Vascular endothelial growth factor A (VEGFA) plays a pivotal role in the first steps of endothelial and haematopoietic development in the yolk sac, as well as in the establishment of the cardiovascular system of the embryo. At the onset of gastrulation, VEGFA is primarily expressed in the yolk sac visceral endoderm and in the yolk sac mesothelium. We report the generation and analysis of a Vegf hypomorphic allele, Vegf(lo). Animals heterozygous for the targeted mutation are viable. Homozygous embryos, however, die at 9.0 dpc because of severe abnormalities in the yolk sac vasculature and deficiencies in the development of the dorsal aortae. We find that providing 'Vegf wild-type' visceral endoderm to the hypomorphic embryos restores normal blood and endothelial differentiation in the yolk sac, but does not rescue the phenotype in the embryo proper. In the opposite situation, however, when Vegf hypomorphic visceral endoderm is provided to a wild-type embryo, the 'Vegf wild-type' yolk sac mesoderm is not sufficient to support proper vessel formation and haematopoietic differentiation in this extra-embryonic membrane. These findings demonstrate that VEGFA expression in the visceral endoderm is absolutely required for the normal expansion and organisation of both the endothelial and haematopoietic lineages in the early sites of vessel and blood formation. However, normal VEGFA expression in the yolk sac mesoderm alone is not sufficient for supporting the proper development of the early vascular and haematopoietic system.

OBJECTIVE

Ordinary least squares (OLS) regression, commonly called linear regression, is often used to assess, or adjust for, the relationship between a continuous independent variable and the mean of a continuous dependent variable, implicitly assuming a linear relationship between them. Linearity may not hold, however, and analyzing the mean of the dependent variable may not capture the full nature of such relationships. Our goal is to demonstrate how combined use of quantile regression and restricted cubic splines (RCS) can reveal the true nature and complexity of relationships between continuous variables.

METHODS

We provide a review of methodologic concepts, followed by two examples using real data sets. In the first example, we analyzed the relationship between cognition and disease duration in multiple sclerosis. In the second example, we analyzed the relationship between length of stay (LOS) and severity of illness in the intensive care unit (ICU).

RESULTS

In both examples, quantile regression showed that the relationship between the variables of interest was heterogeneous. In the second example, RCS uncovered nonlinearity of the relationship between severity of illness and length of stay.

CONCLUSIONS

Together, quantile regression and RCS are a powerful combination for exploring relationships between continuous variables.

Peroxisome proliferator-activated receptors gamma (PPARgamma) are nuclear receptors with essential roles as transcriptional regulators of glucose and lipid homeostasis. PPARgamma are also potent anti-inflammatory receptors, a property that contributes to the neuroprotective effects of PPARgamma agonists in experimental stroke. The mechanism of these beneficial actions, however, is not fully elucidated. Therefore, we have explored further the actions of the PPARgamma agonist rosiglitazone in experimental stroke induced by permanent middle cerebral artery occlusion (MCAO) in rodents. Rosiglitazone induced brain 5-lipoxygenase (5-LO) expression in ischemic rat brain, concomitantly with neuroprotection. Rosiglitazone also increased cerebral lipoxin A(4) (LXA(4)) levels and inhibited MCAO-induced production of leukotriene B4 (LTB(4)). Furthermore, pharmacological inhibition and/or genetic deletion of 5-LO inhibited rosiglitazone-induced neuroprotection and downregulation of inflammatory gene expression, LXA(4) synthesis and PPARgamma transcriptional activity in rodents. Finally, LXA(4) caused neuroprotection, which was partly inhibited by the PPARgamma antagonist T0070907, and increased PPARgamma transcriptional activity in isolated nuclei, showing for the first time that LXA(4) has PPARgamma agonistic actions. Altogether, our data illustrate that some effects of rosiglitazone are attributable to de novo synthesis of 5-LO, able to induce a switch from the synthesis of proinflammatory LTB(4) to the synthesis of the proresolving LXA(4). Our study suggests novel lines of study such as the interest of lipoxin-like anti-inflammatory drugs or the use of these molecules as prognostic and/or diagnostic markers for pathologies in which inflammation is involved, such as stroke.

Oxidation of low density lipoprotein (LDL) occurs in vivo and significantly contributes to the development of atherosclerosis. An important mechanism of LDL oxidation in vivo is its modification with 12/15-lipoxygenase (LO). We have developed a model of minimally oxidized LDL (mmLDL) in which native LDL is modified by cells expressing 12/15LO. This mmLDL activates macrophages inducing membrane ruffling and cell spreading, activation of ERK1/2 and Akt signaling, and secretion of proinflammatory cytokines. In this study, we found that many of the biological activities of mmLDL were associated with cholesteryl ester (CE) hydroperoxides and were diminished by ebselen, a reducing agent. Liquid chromatography coupled with mass spectroscopy demonstrated the presence of many mono- and polyoxygenated CE species in mmLDL but not in native LDL. Nonpolar lipid extracts of mmLDL activated macrophages, although to a lesser degree than intact mmLDL. The macrophage responses were also induced by LDL directly modified with immobilized 12/15LO, and the nonpolar lipids extracted from 12/15LO-modified LDL contained a similar set of oxidized CE. Cholesteryl arachidonate modified with 12/15LO also activated macrophages and contained a similar collection of oxidized CE molecules. Remarkably, many of these oxidized CE were found in the extracts of atherosclerotic lesions isolated from hyperlipidemic apoE(-/-) mice. These results suggest that CE hydroperoxides constitute a class of biologically active components of mmLDL that may be relevant to proinflammatory activation of macrophages in atherosclerotic lesions.

To determine the tissue-specific functions of SOCS-1, mice were generated in which the SOCS-1 gene could be deleted in individual tissues. A reporter gene of SOCS-1 promoter activity was also inserted. Using the reporter, high SOCS-1 expression was found at the CD4(+)CD8(+) stage in thymocyte development. To investigate the function of this expression, the SOCS-1 gene was specifically deleted throughout the thymocyte/T/NKT cell compartment. Unlike SOCS-1(-/-) mice, these mice did not develop lethal multiorgan inflammation but developed multiple lymphoid abnormalities, including enhanced differentiation of thymocytes toward CD8(+) T cells and very high percentages of peripheral CD8(+) T cells with a memory phenotype (CD44(hi)CD25(lo)CD69(lo)). These phenotypes were found to correlate with hypersensitivity to the gamma-common family of cytokines.

Leukodystrophies are a heterogeneous group of inherited neurodegenerative disorders characterized by abnormal white matter visible by brain imaging. It is estimated that at least 30% to 40% of individuals remain without a precise diagnosis despite extensive investigations. We mapped tremor-ataxia with central hypomyelination (TACH) to 10q22.3-23.1 in French-Canadian families and sequenced candidate genes within this interval. Two missense and one insertion mutations in five individuals with TACH were uncovered in POLR3A, which codes for the largest subunit of RNA polymerase III (Pol III). Because these families were mapped to the same locus as leukodystrophy with oligodontia (LO) and presented clinical and radiological overlap with individuals with hypomyelination, hypodontia and hypogonadotropic hypogonadism (4H) syndrome, we sequenced this gene in nine individuals with 4H and eight with LO. In total, 14 recessive mutations were found in 19 individuals with TACH, 4H, or LO, establishing that these leukodystrophies are allelic. No individual was found to carry two nonsense mutations. Immunoblots on 4H fibroblasts and on the autopsied brain of an individual diagnosed with 4H documented a significant decrease in POLR3A levels, and there was a more significant decrease in the cerebral white matter compared to that in the cortex. Pol III has a wide set of target RNA transcripts, including all nuclear-coded tRNA. We hypothesize that the decrease in POLR3A leads to dysregulation of the expression of certain Pol III targets and thereby perturbs cytoplasmic protein synthesis. This type of broad alteration in protein synthesis is predicted to occur in other leukoencephalopathies such as hypomyelinating leukodystrophy-3, caused by mutations in aminoacyl-tRNA synthetase complex-interacting multifunctional protein 1 (AIMP1).

BACKGROUND

A systematic review of the literature was performed to estimate the impact of hemiarthroplasty compared with total shoulder arthroplasty on function and range of motion in patients suffering from osteoarthritis of the shoulder.

METHODS

We conducted an electronic search for relevant studies published in any language from 1966 to 2004, a manual search of the proceedings from five major orthopaedic meetings from 1995 to 2003, and a review of the reference lists from potentially relevant studies. Four randomized clinical trials, with similar eligibility criteria and surgical techniques, that compared hemiarthroplasty and total shoulder arthroplasty for the treatment of primary osteoarthritis of the shoulder were found to be eligible. Authors from three of the four studies provided original patient data. Analysis of covariance focused on the two-year outcome and included a comparison of the aggregate University of California at Los Angeles shoulder score, four University of California at Los Angeles domain scores, and range of motion.

RESULTS

A total of 112 patients (fifty managed with hemiarthroplasty and sixty-two managed with total shoulder arthroplasty), who had a mean age of sixty-eight years, were included in this analysis. A significant moderate effect was detected in the function domain of the University of California at Los Angeles shoulder score (p < 0.001) in favor of total shoulder arthroplasty (mean [and standard deviation], 8.1 +/- 0.3) compared with hemiarthroplasty (mean, 6.6 +/- 0.3). A significant difference in the pain score was found in favor of the total shoulder arthroplasty group (p < 0.0001). However, the large degree of heterogeneity (p = 0.006, I(2) = 80.2%) among the studies decreased our confidence that total shoulder arthroplasty provides a true, consistent benefit with regard to pain. There was a significant difference in the overall change in forward elevation of 13 degrees (95% confidence interval, 0.5 degrees to 26 degrees ) in favor of the total shoulder arthroplasty group (p = 0.008).

CONCLUSIONS

At a minimum of two years of follow-up, total shoulder arthroplasty provided better functional outcome than hemiarthroplasty for patients with osteoarthritis of the shoulder. Since continuous degeneration of the glenoid after hemiarthroplasty or glenoid loosening after total shoulder arthroplasty may affect the eventual outcome, longer-term (five to ten-year) results are necessary to determine whether these findings remain consistent over time.