CCR5 promoter polymorphism and HIV-1 disease progression. Multicenter AIDS Cohort Study (MACS)

BACKGROUND: The rate of progression to AIDS varies among individuals infected with HIV-1. Factors responsible include two inherited human alleles, CCR5 delta32 and CCR2-641, which alter the protein-coding regions for the HIV-1 coreceptors/chemokine receptors CCR5 and CCR2b. We tested the hypothesis that polymorphisms of the CCR5 promoter might affect the rate of progression of HIV-1 infected people to AIDS. METHODS: We used directed heteroduplex analysis to identify polymorphism in the CCR5 promoter. Promoter-variants were compared in vitro with a chloramphenicol acetyltransferase reporter gene, and in vivo by genotyping HIV-1 seroconvertors discordant at polymorphous loci. FINDINGS: An A/G polymorphism was identified at basepair 59029 (Genbank U95626) in the CCR5 promoter. Both promoter alleles were common (43-68% allelic frequency for 59029-A depending on race). When in-vitro promoter activity was measured, 59029-G had 45% lower activity than 59029-A (p=0.05). In a cohort of HIV-1 seroconvertors lacking both CCR5 delta32 and CCR2-641, 59029-G/G individuals progressed to AIDS on average 3.8 years more slowly than 59029-A/A individuals (p=0.004). 59029-G/A discordance did not correlate with discordant rates of infection. INTERPRETATION: Our results are consistent with the hypothesis that CCR5 is important in HIV-1 pathogenesis. CCR5 59029-G/G appears to be protective relative to CCR5 59029-A/A, and about twice as protective relative to CCR5 delta32 or CCR2-641. This effect may be the result of reduced CCR5 mRNA production. These results identify the first site in the CCR5 promoter that may be a useful target for treatment of HIV-1 infection.     

Association of systemic lupus erythematosus with promoter polymorphisms of the mannose-binding lectin gene

OBJECTIVE: To investigate the distribution of promoter variants of the mannose-binding lectin (MBL) gene and correlations between the promoter variants and serum MBL concentrations in Chinese patients with systemic lupus erythematosus (SLE) and in healthy Chinese controls. METHODS: We studied the serum MBL levels and codon 54 mutation in 112 Chinese patients with SLE and 110 healthy controls. Genotyping of promoter variants of the MBL gene were done by polymerase chain reaction and allele-specific oligonucleotide hybridization. RESULTS: We found significant differences in the distribution of the 2 pairs of promoter polymorphisms, H/L and Y/X, between SLE patients and controls (P=0.018 and P=0.019, respectively). Analysis of the correlation between promoter haplotypes and serum MBL levels revealed HY as the highest-producing, LY as the intermediate-producing, and LX as the lowest-producing haplotypes. The LX haplotype was present at a frequency of 0.259 in SLE patients and 0.154 in controls and was significantly associated with SLE (P=0.019, odds ratio 1.79, 95% confidence interval 1.12-2.85). CONCLUSION: The low-producing promoter polymorphism of the MBL gene is associated with SLE, and a low serum MBL level is a risk factor for SLE. Even allowing for promoter polymorphisms and structural mutations of the MBL gene, serum MBL levels in SLE patients are still lower than those in controls, suggesting a trans-factor in regulating serum MBL levels.     

Association of HLA profiles with early plasma viral load, CD4+ cell count and rate of progression to AIDS following acute HIV-1 infection. Multicenter AIDS Cohort Study

The products of a growing number of genes have been shown to display seemingly contradictory functions; namely, the induction of tumorigenesis and the induction of apoptosis. Heregulin's involvement in oncogenesis occurs through its interactions with members of the EGF receptor tyrosine kinase family. Recently one isoform of heregulin, beta2b, was isolated in an in vitro screen for dominant, apoptosis-inducing genes in kidney epithelial cells. Here we show that heregulin is also capable of mediating apoptosis in human and murine mammary tumor cell lines and murine tumors. Furthermore, through transfection of the human breast cancer cell line MCF-7 with the truncated transmembrane/cytoplasmic segment of the heregulin gene, we show that the intracellular region of the heregulin precursor is sufficient for induction of apoptosis. Through the use of DNA fragmentation assays we also show that apoptosis occurs in cell lines established from heregulin-induced mammary gland tumors. TdT addition of digoxigenin labeled nucleotides to 3' OH ends of DNA breaks recapitulated these results in the actual tumors. Finally, over-expression of heregulin is shown to lead to the down-regulation of Bcl-2, an inhibitor of apoptosis. Conversely, the transfection of Bcl-2 into MCF-7 cells inhibits heregulin-mediated programmed cell death.     

Effectiveness of potent antiretroviral therapy on time to AIDS and death in men with known HIV infection duration. Multicenter AIDS Cohort Study Investigators

CONTEXT: Time to development of acquired immunodeficiency syndrome (AIDS) and time to death have been extended with the increased use of combination therapy and protease inhibitors. Cohort studies following up persons with human immunodeficiency virus (HIV) infection in periods characterized by different therapies offer the opportunity to estimate therapy effectiveness at the population level. OBJECTIVE: To assess the effectiveness of self-reported, long-term potent antiretroviral therapy in a cohort of 536 men whose duration of HIV infection was known (seroconverters). DESIGN: Cohort study. The cohort was compared for time to development of AIDS and time to death in 1984 to 1990, 1990 to 1993, 1993 to July 1995, and July 1995 to July 1997 when the major treatments were no therapy, monotherapy, combined therapy, and potent antiretroviral therapy, respectively. Survival analysis methods with time zero set as the date of seroconversion and incorporating staggered entries into each period were used. Mean CD4 cell change, stratified by infection duration, was determined for each period using a random effects model. SETTING: The Multicenter AIDS Cohort Study (MACS) in 4 urban areas (Baltimore, Md; Chicago, III; Los Angeles, Calif; and Pittsburgh, Pa). PARTICIPANTS: A total of 5622 men who were 18 years or older were enrolled into MACS. Of the 5622, there were 2191 HIV-positive individuals at enrollment. Of the 3431 men who were HIV-negative, 536 were observed to seroconvert and were followed up for up to 13 years. The group of 536 who seroconverted constituted the study population. MAIN OUTCOME MEASURES: Time from seroconversion to development of AIDS and to death and change in CD4 cell count. RESULTS: A total of 231 seroconverters developed AIDS, and 200 men died. Using 1990 to 1993 as the reference period, the relative hazard of AIDS was 1.04 (95% confidence interval [CI], 0.73-1.48) during 1993 to July 1995 and 0.35 (95% CI, 0.20-0.61) during July 1995 to July 1997. Relative hazards of death were 0.87 (95% CI, 0.58-1.31) and 0.62 (95% CI, 0.38-1.01 ) for the same periods. The relative time (the factor by which times are contracted or expanded) to development of AIDS was 0.97 (95% CI, 0.86-1.09) for 1993 to July 1995 and 1.63 (95% CI, 1.40-1.89) for July 1995 to July 1997. Relative survival time for 1993 to July 1995 was 1.01 (95% CI, 0.91-1.12) and for July 1995 to July 1997 was 1.21 (95% CI, 1.07-1.36) relative to 1990 to 1993. The rate of CD4 cell count decline in July 1995 to July 1997 was significantly lower (P<.05) compared with the previous 2 periods. CONCLUSIONS: In the calendar period when potent antiretroviral therapy was introduced, the time to development of AIDS and time to death were extended, and rate of CD4 cell count decline was arrested.     

Serum HIV-1 RNA levels and time to development of AIDS in the Multicenter Hemophilia Cohort Study

Normal women produce small amounts of active androgens. When androgen levels are elevated, such as for example in the polycystic ovary syndrome, this is followed by the development of male physical characteristics and muscle mass, structure and function as well as android adipose tissue distribution and function. Psychological features and stress reactions also seem similar to those of men. Such women have an increased risk of developing hypertension, non-insulin-dependent diabetes mellitus and cardiovascular disease. Recent data have shown that these physical, and psychological characteristics, as well as risk of ill health, are also found in the population of women selected at random. Women in the lowest quintiles of levels of sex-hormone-binding globulin--an indicator inversely related to active androgens--are at risk of developing hypertension, non-insulin-dependent diabetes mellitus and cardiovascular mortality. The mechanism probably includes muscular insulin resistance, following a relative androgen excess. It is thus apparent that androgens, even within the highest levels of the nonselected population of women, are powerful predictors of serious disease development. The population at risk might be as large as about 20% of middle-aged women. This is an area of female disease risk which requires more attention in screening and intervention procedures.     

Impact of antiretroviral combination therapies on AIDS surveillance reports in Switzerland. Swiss HIV Cohort Study

BACKGROUND: AIDS reporting in Switzerland is mandatory by law. For the first time since the beginning of the epidemic, health authorities observed a decline in AIDS surveillance reports, from 545 new cases in 1995 to 459 in 1996, a decrease of 86 cases. OBJECTIVE: To examine the extent to which this decline in AIDS surveillance reports is attributable to the introduction of antiretroviral combination therapy. Patients and setting: Swiss HIV Cohort Study, a multicentre cohort of adult HIV-infected patients with national coverage. Participants at risk of developing a first AIDS-defining event, defined as persons with a CD4 cell count below 200 x 10(6)/l or in clinical stage B, were studied. METHODS: A parametric statistical survival model was used to estimate the number of AIDS cases expected in the absence of combination therapies. Taking reporting delays into account, the effect of the introduction of combination therapies in the cohort on national AIDS reports was estimated from the difference between the number of expected and observed cases. RESULTS: A total of 4915 participants contributed 10755 person-years and 2366 initial AIDS events. Between 1990 and 1994, about 35% received antiretroviral therapy, predominantly monotherapy. In 1995 and 1996, the prevalence of antiretroviral therapy increased steadily due to the introduction of dual and triple combinations. The mid-year prevalence of use of combination therapies was 6% in 1994, 13% in 1995, and 48% in 1996. The difference between expected and observed cases per half-year increased from 12 in the first 6 months of 1994 to 69 in the second half of 1996. Taking reporting delays into account, we estimated that 43 (95% confidence interval, 17-69) of the deficit of 86 reports could be attributed to combination therapies. CONCLUSION: The introduction of antiretroviral combination therapies in a single cohort study explained 50% of the decline in national AIDS surveillance reports. Monitoring the use and effectiveness of antiretroviral therapy must become an important component of AIDS surveillance systems.     

Microscopic polyangiitis. Delineation of a cutaneous-limited variant associated with antimyeloperoxidase autoantibody

Identification of inexpensive and technically simple immunological tests useful in predicting the progression to AIDS in human immunodeficiency virus (HIV)-infected patients would be especially welcome in developing countries, in which 80% of HIV-infected patients reside and health budgets are low. In the current study, we evaluated CD4+ and total lymphocyte counts and the concentrations in serum of beta 2-microglobulin, p24 antigen, and immunoglobulin A (IgA) as predictors of disease progression in 74 Panamanian HIV-positive patients and 50 HIV-negative healthy individuals. Total lymphocyte and CD4(+)-cell counts for AIDS patients (1,451 +/- 811 cells/microliters, P < 0.001, and 238 +/- 392 cells/microliters, P < 0.0001, respectively and asymptomatic patients (2,393 +/- 664 cells/microliters, P > 0.05, and 784 +/- 475 cells/microliters, P < 0.001, respectively) were lower than those observed for healthy subjects (2,596 +/- 631 cells/microliters and 1,120 +/- 296 cells/microliters, respectively). The levels of beta 2-microglobulin and IgA in serum were significantly elevated in patients with AIDS (5.7 +/- 3.6mg/liter, P < 0.001, and 541 +/- 265 mg/dl, P < 0.0002, respectively) and asymptomatic infected subjects (3.4 +/- 2.1 mg/liter, P = 0.001, and 436 +/- 216 mg/dl, P < 0.0001, respectively) compared with the levels in healthy subjects (2.2 +/- 0.7 mg/liter and 204 +/- 113 mg/dl, respectively). Nonstatistically significant differences (P > 0.05) for concentrations of p24 antigen between asymptomatic infected patients (29 +/- 13 pg/ml) and AIDS patients (40 +/- 23 pg/ml) were observed. Total lymphocyte counts of 1,750 cells/microliters or less, CD4 counts of 200 cells/microliters or less, beta 2-microglobulin concentrations in serum of 4 mg/liter or higher, concentrations of IgA in serum of 450 mg/dl or higher, and the presence in serum of p24 antigen were correlated with elevated risks for developing AIDS. Monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring both total lymphocytes and beta 2-microglobulin identified 91% of the AIDS patients; these assays may allow reductions in the annual number of CD4(+)-cell evaluations and the costs associated with monitoring the immune status of HIV-positive patients.     

The rate of CD4 decline as a determinant of progression to AIDS independent of the most recent CD4 count. The Italian Seroconversion Study

Horse liver alcohol dehydrogenase contains two tryptophan residues per subunit, Trp-15 on the surface of the catalytic domain and Trp-314 buried in the interface between the subunits of the dimer. We studied the contributions of the tryptophans to fluorescence and catalytic dynamics by substituting Trp-314 with a leucine residue and making two compensatory mutations that were required to obtain a stable protein, leading to the triple mutant M303F-L308I-W314L enzyme. The substitutions increased by two- to sixfold the turnover numbers for ethanol oxidation, acetaldehyde reduction, and the dissociation constants of the coenzymes. The rate of the exponential burst phase for the transient oxidation of ethanol increased slightly, but the rate of dissociation of the enzyme-NADH complex still limited turnover of ethanol, as for wild-type enzyme. The three substitutions at the dimer interface apparently activate the enzyme by allowing more rapid conformational changes that accompany coenzyme binding, probably due to movement of the loop containing residues 293 to 298. The emission spectrum of M303F-L308I-W314L enzyme, which contains Trp-15, was redshifted compared to wild-type enzyme. Time-resolved fluorescence measurements with the triple mutant show that the decay of Trp-15 is dominated by a approximately 7-ns component. In the mutant enzyme with Trp-15 substituted with phenylalanine, the decay of Trp-314 is dominated by a approximately 4-ns component. Solute quenching data for wild-type enzyme and the mutants show that only Trp-15 is exposed to iodide and acrylamide, whereas Trp-314 is inaccessible. The luminescence properties of the tryptophan residues in the mutated enzymes are consistent with conclusions from studies of the wild-type enzyme [M. R. Eftink, 1992, Adv. Biophys. Chem. 2, 81-114].     

Neurologic problems of the lower extremity associated with HIV and AIDS

Lower extremity symptoms are caused by lesions at any level of the neuraxis, from cortex to muscle. HIV affects virtually every level of the nervous system, either directly or indirectly. The presence of pathology at multiple levels and by multiple processes further complicates the bedside diagnosis of a patient with AIDS and neurologic symptoms. Many neuropathies and other conditions that affect the lower extremities can be identified with careful history and physical examination, confirmed with limited testing, and can be treated successfully. Distal symmetric polyneuropathy is the most common lower extremity disorder, but it must be distinguished from similar-appearing neuropathies caused by medications, B12 deficiency, or vasculitis. Diffuse infiltrative lymphocytosis syndrome also causes a painful peripheral neuropathy that must be distinguished from distal symmetric polyneuropathy. Inflammatory demyelinating polyneuropathies are characterized by muscle weakness. They occur in early, asymptomatic HIV infection and respond to plasmapheresis or steroids. Mononeuropathies in patients with CD4 counts more than 200 often resolve on their own. Multiple mononeuropathies, which occur in patients with CD4 counts less than 50, are often associated with cytomegalovirus infection and may follow a rapidly progressive course unless treated promptly and aggressively. Progressive polyradiculopathy occurs late in the course of AIDS, is often caused by cytomegalovirus, is rapidly progressive, and generally is fatal unless recognized and treated promptly. Muscle weakness, myalgia, and fatigue are common in HIV and have multiple causes. Lower extremity spasticity may be caused by treatable etiologies such as spinal cord abscess, tumor, disc compression, B12 deficiency, or ischemia. Gait disturbances are common but nonspecific and may be caused by treatable neurologic disorders at any level of the neuraxis.     

Maternal factors associated with perinatal HIV-1 transmission: the French Cohort Study: 7 years of follow-up observation. The French Pediatric HIV Infection Study Group

The effects of pretreatment with inducers of hepatic cytochrome P450 isoenzymes (phenobarbital, dexamethasone and beta-naphthoflavone) on the metabolism of d-fenfluramine (d-F) and its acute and long-lasting indole-depleting effects were studied in rats, in an effort to obtain further information on the importance of hepatic drug metabolism in relation to its neurochemical actions. Twenty-four hours after the last dose of each inducer, rats were injected with d-F hydrochloride (5 mg/kg, IP) and killed at various times thereafter for parallel determination of indoles and drug concentrations in plasma and brain. Additional rats were treated as above and killed 1 week after d-F hydrochloride (5 and 10 mg/kg) to study the recovery of indole in the cortex, a particularly sensitive brain area. Phenobarbital and beta-naphthoflavone and, to a lesser degree, dexamethasone, stimulated the metabolism of d-F, as evidenced by a decrease in plasma and brain areas under the curve (AUC) compared to vehicle-treated rats. This indicated that multiple isoenzymes are capable of mediating the drug's metabolism, primarily by N-dealkylation to d-norfenfluramine (d-NF). None of the inducers raised plasma and brain AUC of the nor-derivative, and in fact phenobarbital and particularly beta-naphthoflavone reduced it. These different effects were even apparent in rats given d-NF (2.5 mg/kg), indicating that both phenobarbital and beta-naphthoflavone also stimulate the sequential metabolism of the nor-metabolite (by N-deamintaion) which, however, is apparently enhanced most actively by beta-naphthoflavone-inducible forms of P-450.(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of oxidative imbalance in progression to AIDS: effect of the thiol supplier N-acetylcysteine

In this study we investigate the redox profile of HIV+ patients at different stages of disease with regard to immunological parameters, i.e., the number of circulating CD4+ and CD8+ lymphocytes. For this purpose, peripheral blood mononuclear cells (PBMCs) obtained from healthy donors, HIV+ patients in the asymptomatic phase, long-term nonProgressors (LTNPs), and AIDS patients have been considered. Cells have been exposed in vitro to the prooxidizing agent menadione, which is able to induce superoxide anion formation, and the susceptibility of the cells to the induced oxidative stress was estimated. Moreover, the possibility that the susceptibility of the cells to oxidative stress might be reduced by preexposing them to the antioxidizing agent N-acetylcysteine (NAC) has also been analyzed. The results obtained can be summarized as follows: (1) treatment with the prooxidant agent is capable of inducing massive morphological alterations in PBMCs. In particular, a significant correlation was found between the decrease in number of CD4+ lymphocytes in patients at different stages of disease and the susceptibility of their PBMCs to oxidative stress; (2) preincubation with NAC was able to preserve partially the ultrastructural characteristics of PBMCs isolated from HIV+ patients. In particular, a direct relationship was found between the efficacy of NAC protection and CD4 counts; (3) evaluation of the plasma index of peroxidation and the number of circulating CD4 lymphocytes indicates the existence of a positive correlation between "systemic" oxidative imbalance and stage of the disease; and (4) cells from LTNPs display either oxidative susceptibility or oxidative markers similar to those of healthy donor cells. Our study suggests that the redox profile of patients may be considered a predictive marker of AIDS progression and that the acute infection and the asymptomatic phase of the disease may represent a useful period in which the combined use of antiretroviral and antioxidant drugs may be beneficial.     

Survival of AIDS patients according to type of AIDS-defining event. The AIDS in Europe Study Group

The ability of hemoglobin, modified by H2O2 or HOCl/OCl-, to induce lipid peroxidation (LPO) in low density lipoproteins (LDL) was studied, as well as the effects of haptoglobin. It was found that Hb modification by H2O2 or HOCl/OCl- increased generation of TBA-reactive substances in low density lipoproteins. Modified Hb was as double or more reactive compared to intact Hb. Free radical scavengers (ethanol and mannitol) gave no effect on LPO in LDL. On the other hand, ferric iron chelator desferrioxamine decreased LPO 5-6 times. Ferrous iron chelator- o-phenanthroline was effective only in the case of LPO, induced by H2O2 modified Hb. Haptoglobin (plasma protein forming complexes with Hb) decreased LPO induced by both intact or HOCl/OCl modified Hb. The results of the paper show that modification of Hb by H2O2 or HOCl/OCl- increase the ability of Hb to induce LPO in LDL, probably due to metHb, ferrylHb or free iron production.     

Coping with the threat of AIDS: An approach to psychosocial assessment.

Discusses research issues associated with the study of the effects of acquired immune deficiency syndrome (AIDS) on the psychosocial welfare of gay males, focusing on 5 areas: obtaining qualitative data, developing inventories, sampling in the gay community, building community networks, and characterizing the crisis of AIDS. Behavioral changes wrought by AIDS in this population are described; most changes have involved the reduction of the number and type of sexual activities. Altered relationships with heterosexuals and problems faced by heterosexual researchers in working with this population are examined. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pre-AIDS mortality from natural causes associated with HIV disease progression: evidence from the European Seroconverter Study among injecting drug users

OBJECTIVES: To study differences in pre-AIDS mortality between European cohorts of injecting drug users (IDU) and to evaluate whether pre-AIDS mortality increased with time since HIV seroconversion and decreasing CD4 count. METHODS: The study population consisted of 664 IDU with documented intervals of HIV seroconversion from eight cohort studies. Differences in pre-AIDS mortality were studied between European sites; an evaluation of whether pre-AIDS mortality increased with time since HIV seroconversion and decreasing CD4 count was carried out using Poisson regression. RESULTS: One hundred and seven IDU died, of whom 57 did not have AIDS. Pre-AIDS causes of death were overdose/suicide (49%), natural causes such as bacterial infections/cirrhosis (40%), and unintentional injuries/unknown (11%). Considering pre-AIDS death and AIDS as competing risks, 14.7% were expected to have died without AIDS and 17.3% to have developed AIDS at 7 years from seroconversion. No statistically significant differences in pre-AIDS mortality were found between European regions, men and women, age categories and calendar time periods. Overall pre-AIDS mortality did not increase with time since seroconversion, but did increase with decreasing CD4 count. Evaluating cause-specific mortality, only pre-AIDS mortality from natural causes appeared to be associated with time since seroconversion as well as immunosuppression. For natural causes, the death rate per 100 person-years was 0.13 the first 2 years after seroconversion, 0.73 in years 2-4 [risk relative (RR) to years 0-2, 5.6], 1.83 in years 4-6 (RR, 14.0) and 1.54 for > or = 6 years (RR, 11.7). This rate was 0 for a CD4 cell count > or = 500 x 10(6)/l, 1.06 for 200-500 x 10(6)/l and 4.06 for < 200 x 10(6)/l (RR versus > or = 200 x 10(6)/l, 7.0). In multivariate analysis, both CD4 count and time since seroconversion appeared to be independently associated with death from natural causes; CD4 count appeared to be the strongest predictor (adjusted RR, 5.9). CONCLUSIONS: A high pre-AIDS mortality rate was observed among IDU. No significant differences were observed across European sites. Pre-AIDS mortality from natural causes but not from overdose and suicide was associated with HIV disease progression.     

Kaposi's sarcoma and non-Hodgkin's lymphoma following the diagnosis of AIDS. Multistate AIDS/Cancer Match Study Group

We linked records of 83,434 AIDS cases reported to AIDS registries through 1990 to cancer registry records during times when overlap in registration existed. Of 8,496 Kaposi's-sarcoma (KS) cases meeting enrollment criteria, 1,045 occurred semesters 2 through 4 (6 through 23 months) after another AIDS-defining illness. KS risk in this period after AIDS declined steadily over the 1980s. Adjusting for age, gender, ethnic origin and calendar time period, we found the relative risk (RR) of KS to be 106,000 for homo/bisexual men with AIDS and 13,000 for other men with AIDS. Risk was highest for homo/bisexual men between 30 and 39 years old and among 20- to 29-year-old non-homo/bisexual men. The RR in black men was approximately half that reported in white men among homo-bisexual men and others. Between the second and fourth semester after AIDS, the ratio of RR of KS to that of non-AIDS-related cancers increased 1.5-fold. In a similar analysis, there were 335 non-Hodgkin's lymphoma (NHL) cases in semesters 2 through 4 after AIDS. The overall risk was elevated 283-fold in homo/bisexual men and the RR ratio increased 1.8-fold between semester 2 and 4 after AIDS. In summary, the risk of KS following another AIDS-defining illness is strikingly high, more in white men than in black men, and the risks of KS and, especially, NHL appear to increase with time from AIDS.     

Hyperactivity to quinine associated with osmotic thirst in the rat.

Studied cellular and extracellular fluid depletion in 5 experiments with Sherman female albino rats (N = 103). Drinking in response to cellular dehydration, but not in response to water deprivation, was severely disrupted by mild quinine adulteration of the drinking fluid. Cellular dehydration in conjunction with deprivation, although enhancing the intake of water, actually suppressed quinine intake. In contrast, intravascular fluid depletion added to water privation enhanced intake both of water and of quinine solutions. It is concluded that the heightened reactivity to quinine which accompanies cellular dehydration reflects a specific property of the osmotic-thirst mechanism. (24 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Race/ethnicity misclassification of persons reported with AIDS. The AIDS Mortality Project Group and The Supplement to HIV/AIDS Surveillance Project Group

Oxidative modification of high density lipoproteins (HDL) may alter their capacity to mediate cellular cholesterol efflux. We studied the kinetics of copper-mediated oxidation of HDL and cholesterol efflux mediated by unmodified and oxidized HDL (oxHDL). Oxidation was measured by increases in absorbance at 234 nm (delta A234), production of thiobarbituric acid reactive substances (TBARS) and loss of trinitrobenzene sulfonic acid reactivity. Oxidation was dependent on copper concentration and showed a lag phase and propagation phase. Efflux of cholesterol from J774 macrophages measured by appearance of cellular [3H]cholesterol in the medium was lower by 16% after 4 h and 36% after 24 h with oxHDL compared to HDL. OxHDL-mediated efflux was also lower by 27% to 37% at lipoprotein concentrations of 10 to 200 micrograms protein/ml. Cholesterol efflux correlated negatively with TBARS production (r = -0.97, P < 0.003) and delta A234 (r = -0.77, P < 0.080). There was no difference in efflux mediated by apoproteins prepared from HDL and oxHDL. Efflux measured by change in cholesterol mass in medium was 78% lower with oxHDL. Inhibition of oxidation with butylated hydroxytoluene maintained the capacity of HDL to stimulate efflux. These results suggest that oxidation of HDL may impair its protective role against atherosclerosis.     

A cysteinyl leukotriene 2 receptor variant is associated with atopy in the population of Tristan da Cunha

The clinical heterogeneity of asthma suggests that the contribution of genetic variability in candidate gene loci to well-defined phenotypes, such as atopy, may be examined to identify appropriate genetic risk factors for asthma. The gene encoding the cysteinyl leukotriene 2 (CysLT2) receptor has been implicated in atopy since it is localized to a region of chromosome 13q14 that has been linked to atopy in several populations and the cysteinyl leukotrienes are known to activate eosinophils and mast cells in atopy. Accordingly, we analysed the contribution of CysLT2 receptor gene variation to atopy in the inhabitants of Tristan da Cunha, a population characterized by both a founder effect and a 47% prevalence of atopy. Single-stranded conformational polymorphism analysis revealed four variants. Among these, the M201V [corrected] variant was activated with four-fold less potency by leukotriene D4 (LTD4) in a calcium flux assay. The CysLT2 receptor partial agonist, BAY u9773, also showed four-fold lower potency on the M201V [corrected] variant. The M201V [corrected] mutation is located within the extracellular region of the fifth transmembrane spanning domain of CysLT2 receptor, a position that may alter ligand binding and effector signalling. The novel M201V [corrected] CysLT2 receptor variant was associated with atopy (21%) on Tristan da Cunha compared with those who were non-atopic (7%) (Fisher's exact test, P=0.0016) in a manner that was independent of asthma (two-way ANOVA, P=0.0015). This represents the first association of a coding mutation in the CysLT2 receptor gene, located on chromosome 13q14, with the atopic phenotype found in the Tristan da Cunha population.