Diffusion of macromolecules and virus-like particles in human cervical mucus.

To determine whether or not large macromolecules and viruses can diffuse through mucus, we observed the motion of proteins, microspheres, and viruses in fresh samples of human cervical mucus using fluorescent recovery after photobleaching and multiple image photography. Two capsid virus-like particles, human papilloma virus (55 nm, approximately 20,000 kDa) and Norwalk virus (38 nm, approximately 10,000 kDa), as well as most of the globular proteins tested (15-650 kDa) diffused as rapidly in mucus as in saline. Electron microscopy of cervical mucus confirmed that the mesh spacing between mucin fibers is large enough (20-200 nm) for small viruses to diffuse essentially unhindered through mucus.

Expression of functional melanocortin-4 receptor in the hypothalamic GT1-1 cell line.

Mutations in the melanocortin-4 receptor (MC4-R) cause obesity in both mice and humans, and the receptor is presumed to have an important role in the regulation of energy homeostasis. The MC4-R is expressed in discrete sets of neurons in the central nervous system, and thus it has been technically difficult to study the regulation of expression and the signaling mechanisms of this receptor. We report here a neuronal cell line that exhibits endogenous functional expression for the MC4-R.

Origins of vaginal acidity: high D/L lactate ratio is consistent with bacteria being the primary source.

Background: The origin of the lactic acid that acidifies the vagina is not well established. It is widely accepted that during times of high oestrogen (during the neonatal period and again during a woman's reproductive years) large amounts of glycogen are deposited in the vaginal epithelium and that the glycogen is anaerobically metabolized to lactic acid. What is not established is whether lactic acid is primarily produced by vaginal bacteria or by vaginal epithelial cells.

Long-term evaluation of T-cell subset changes after effective combination antiretroviral therapy during asymptomatic HIV-infection.

Demonstration of long-lived HIV-reservoirs resistant to the effects of combination antiretroviral therapy raises concern over the ability of treatment to maintain long-term beneficial alterations in T-cell subset composition. To address this issue, we have examined the effect of antiretroviral therapy on T-cell subset change during early HIV-infection in a 2-year prospective open-label trial composed of treatment-naive asymptomatic HIV-infected patients with CD4+ T-cell counts > or =400 cells/microl. Therapy consisted of double (zidovudine and lamivudine) or triple (zidovudine, lamivudine, and ritonavir) combination antiretroviral therapy.

Tests of Buffergel for contraception and prevention of sexually transmitted diseases in animal models.

Background: BufferGel is a novel spermicidal and microbicidal gel formulated to maintain the natural protective acidity of the vagina by acidifying semen, which otherwise alkalinizes the vagina.

Goal: To test the efficacy of BufferGel for preventing sexually transmitted infections and pregnancy in animal models.

Study Design: Animals were challenged with pathogens or sperm after pretreatment with both test and control agents, or after no pretreatment, then evaluated for infection or pregnancy using standard methods.

Leptin activates anorexigenic POMC neurons through a neural network in the arcuate nucleus.

The administration of leptin to leptin-deficient humans, and the analogous Lepob/Lepob mice, effectively reduces hyperphagia and obesity. But common obesity is associated with elevated leptin, which suggests that obese humans are resistant to this adipocyte hormone. In addition to regulating long-term energy balance, leptin also rapidly affects neuronal activity.

Melanocortin-4 receptor is required for acute homeostatic responses to increased dietary fat.

In response to moderately increased dietary fat content, melanocortin-4 receptor-null mutant (MC4R-/-) mice exhibit hyperphagia and accelerated weight gain compared to wild-type mice. An increased feed efficiency (weight gain/kcal consumed) argues that mechanisms in addition to hyperphagia are instrumental in causing weight gain. We report two specific defects in coordinating energy expenditure with food intake in MC4R-/- mice.

Blood mononuclear cells induce regulatory NK T thymocytes in anterior chamber-associated immune deviation.

Injection of antigen into the anterior chamber (AC) of the eye, an immunologically privileged site, is associated with the induction of immune deviation, as evidenced by T helper cell (Th) 1 to Th2 cell polarization. We recently demonstrated that AC-associated immune deviation (ACAID) is a thymus-dependent phenomenon initiated by the formation of regulatory alpha,beta T-cell receptor-positive CD4(-) CD8(-) thymocytes (THYregs). In this study, the afferent and efferent limbs of this immunoregulatory loop were traced from peripheral blood to the thymus and then to the spleen by adoptive-transfer assays.

Structure activity studies of the melanocortin-4 receptor by in vitro mutagenesis: identification of agouti-related protein (AGRP), melanocortin agonist and synthetic peptide antagonist interaction determinants.

In vitro mutagenesis of the mouse melanocortin-4 receptor (mMC4R) has been performed, based upon homology molecular modeling and previous melanocortin receptor mutagenesis studies that identified putative ligand-receptor interactions. Twenty-three mMC4 receptor mutants were generated and pharmacologically characterized using several melanocortin-based ligands [alpha-MSH, NDP-MSH, MTII, DNal (1')(7)-MTII, Nal(2')(7)-MTII, SHU9119, and SHU9005]. Selected mutant receptors possessing significant differences in the melanocortin-based peptide agonist and/or antagonist pharmacology were further evaluated using the endogenous antagonist agouti-related protein fragment hAGRP(83-132) and hAGRP(109-118) molecules.

Reanalysis of unruptured intracranial aneurysm management: effect of a new international study on the threshold probabilities.

Objective: This report updates previous clinical decision analysis for patients with unruptured intracranial aneurysm (UN-AN) based on newly published data and discusses the role of reanalysis in individual decision making.

Methods: The authors employed probabilities for the natural history of UN-AN and results of preventive surgery based on the report by the International Study of Unruptured Intracranial Aneurysms. Probabilistic sensitivity analysis with Monte Carlo simulation and traditional n-way sensitivity analyses were used to assess the uncertainty of clinical decisions.

Role of the central melanocortin system in cachexia.

Individuals affected with either acute or chronic diseases often show disorders of nutrient balance. In some cases, a devastating state of malnutrition known as cachexia arises, brought about by a synergistic combination of a dramatic decrease in appetite and an increase in metabolism of fat and lean body mass. Stimulation of the hypothalamic melanocortin 4 receptor (MC4-R) produces relative anorexia and increased metabolic rate, even in a relatively starved state.

Central melanocortins and the regulation of weight during acute and chronic disease.

Recent advances in our understanding of the regulation of body weight, appetite, and metabolic rate have highlighted the role of the adipose-derived hormone leptin and its receptor as fundamental modulators of these processes. Investigations of the neural targets for leptin action--as well as characterization of the agouti obesity syndrome--have, in turn, led to the discovery of fundamental neural pathways involved in the central regulation of energy homeostasis. In particular, the central melanocortin system has been shown to regulate appetite and metabolic rate in rodents; mutations in this system have been demonstrated to result in obesity in humans.

Impact of TNFalpha, LTalpha, Fc gammaRII and complement receptor on HIV-1 trapping in lymphoid tissue from HIV-infected patients.

Objectives: To investigate HIV trapping mechanisms in patients with acute infection and in asymptomatic individuals prior to and during antiretroviral therapy. To determine the role of complement receptor (CR), Fc gamma receptor II (Fc gammaRII), tumour necrosis factor alpha (TNFalpha), and lymphotoxin alpha (LTalpha) expression in HIV trapping efficiency.

Methods: Lymphoid tissues from three acutely HIV-infected patients and six asymptomatic, chronically HIV-infected patients collected prior to and during antiretroviral therapy were compared with lymphoid tissues from six HIV-seronegative subjects.

Decision analysis of prophylactic treatment for patients with high-risk esophageal varices.

Background: Clinical decision analyses were conducted to quantify the uncertainty and to identify important factors in selection of prophylactic therapy for patients with esophageal varices.

Methods: A Markov model compared variceal ligation, beta-blockers, and "watchful waiting" strategies in terms of bleeding-free life years. Transition probabilities were obtained from meta-analyses of published data.

Genetic models of obesity and energy balance in the mouse.

Obesity is a health problem of epidemic proportions in the industrialized world. The cloning and characterization of the genes for the five naturally occurring monogenic obesity syndromes in the mouse have led to major breakthroughs in understanding the physiology of energy balance and the contribution of genetics to obesity in the human population. However, the regulation of energy balance is an extremely complex process, and it is quickly becoming clear that hundreds of genes are involved.

Immunological and in-vivo neurological studies on a benzoic acid-specific T cell-derived antigen-binding molecule from the serum of a toluene-sensitive patient.

T-cell-derived antigen-binding molecules (TABMs) specific for benzoic acid were isolated from the serum of a toluene-sensitive patient. The resulting purified TABMs (BA-TABMs) did not contain immunoglobulin G and were associated with the cytokine transforming growth factor-beta (TGF-beta). BA-TABMs bound to benzoic acid conjugated to human serum albumin (BA-HSA), as well as to other chemicals conjugated to human serum albumin-including dinitrophenol and oxazolone.

Disproportionate inhibition of feeding in A(y) mice by certain stressors: a cautionary note.

A study of the effects of insulin-induced hypoglycemia in the obese yellow agouti A(y) mouse was initiated to test the hypothesis that the central melanocortin pathways are required for a normal sympathetic response to hypoglycemia. An experimental protocol was performed in which young nonobese male mice were isolated and fasted beginning on day 1, then tested for glucose responses to insulin-induced hypoglycemia on day 2. Normal mice demonstrated the expected glucose rebound to hypoglycemia, exceeding baseline glucose levels by 2-3 times as a consequence of increased gluconeogenesis and glycogenolysis before returning to baseline levels.

A unique metabolic syndrome causes obesity in the melanocortin-3 receptor-deficient mouse.

The central melanocortin system is critical for the long term regulation of energy homeostasis. Null mutations of the melanocortin-4 receptor (MC4-R) are associated with hyperphagia, obesity, and accelerated longitudinal growth in mice and humans. However, little is known about the function of another central melanocortin receptor, the MC3-R.

The central melanocortin system can directly regulate serum insulin levels.

The central melanocortin system has been demonstrated to play a pivotal role in energy homeostasis. Genetic disruption of this system causes obesity in both humans and mice. Previous experiments have shown that centrally-administered melanocortin agonists inhibit food intake and stimulate oxygen consumption.

Detection of antigen-specific human serum proteins related to the T-cell receptor in infectious disease and in an immune response to milk proteins or chemicals.

A monoclonal IgG2 antibody, MG3C9-1 A12, was prepared by immunization of mice with human serum Cohn Fraction III proteins enriched for TCR Ca+ proteins. MG3C9-1 A12 bound to Mr 28,000, antigen-specific TCR Ca+, beta-, and TCR Ca+, beta+ serum proteins associated with TGF-beta1, 2. The IgG2 monoclonal antibody also bound to T-lymphocyte proteins but did not bind to B lymphocyte proteins, human albumin, IgM, IgG, IgA, or TGF-beta1, 2, 3 immunogenic peptides.

Residual HIV-RNA levels persist for up to 2.5 years in peripheral blood mononuclear cells of patients on potent antiretroviral therapy.

The long-term response of 10 asymptomatic, antiretroviral therapy-naive HIV-1-infected patients to potent combination antiretroviral therapy was characterized by monitoring levels of HIV-1 RNA in plasma, peripheral blood mononuclear cells (PBMC), and lymphoid tissue using highly sensitive HIV-1 RNA assays. Although plasma viral loads were continuously suppressed to levels below 50 HIV-1 RNA copies/ml for up to 2.5 years (60-128 weeks), HIV-1 RNA was still detectable at very low levels (1 to 49 HIV-1 RNA copies/ml) in 25% of the samples.

Preventing infectious disease with passive immunization.

Antibodies can prevent infectious diseases by providing passive immune protection. Here we review successful clinical trials of passive immunization and consider some of the unique qualities monoclonal antibodies are now beginning to offer for developing methods for passive immunization against a wide range of infectious diseases.

Measurement of T-cell-derived antigen binding molecules and immunoglobulin G specific to Candida albicans mannan in sera of patients with recurrent vulvovaginal candidiasis.

Immunoglobulin G (IgG) and T-cell-derived antigen binding molecules (TABM) specific to whole Candida extract and to Candida-derived mannans prepared by both the cetryltrimethylammonium bromide (CTAB) and alkaline degradation (PEAT) methods were measured in the sera of women with vulvovaginal candidiasis and controls. In the patients there were significantly higher levels of IgG to both CTAB and PEAT mannans and of TABM to CTAB mannan. TABM specific to CTAB mannan was purified from the serum of a patient with a high titer of this TABM.