Relationship between baroreflex sensitivity, renin suppression and natriuresis in salt-sensitive rabbits.

This study determined the influence of baroreflex sensitivity (BRS) on the rate of urinary sodium excretion and plasma renin activity (PRA) in response to a saline infusion in conscious male rabbits specifically bred for high (Group I; n = 7) and low (Group II; n = 10) BRS and in seven control animals. Only Group II showed significant increases in blood pressure on a chronic high-salt intake. After ensuring that each animal was in sodium balance, a (0.7-0.9%) saline infusion of 3-4 ml/kg per h for 90 min (25% daily sodium intake for each rabbit) was given and urine collected at 15-min intervals via a bladder catheter. No differences were found in control urine volumes, urinary sodium or PRA. Group I excreted over 50% of the sodium load and Group II less than 20% within 90 min. PRA fell by more than 30% within 30 min in six Group I rabbits but decreased by less than 30% or increased in Group II. In the control animals, sodium excretion rates and PRA suppression were also much greater in those with high BRS. A highly significant correlation (r = 0.808, P less than 0.01) was found between the per cent of the sodium load excreted and BRS. It is suggested that the delayed sodium excretion and blood pressure elevation in salt-sensitive subjects may be due to a genetic impairment in baroreflex control of renal sympathetic nerve activity.     

Search for correlates of protective immunity conferred by anthrax vaccine

Vaccination by anthrax protective antigen (PA)-based vaccines requires multiple immunization, underlying the need to develop more efficacious vaccines or alternative vaccination regimens. In spite of the vast use of PA-based vaccines, the definition of a marker for protective immunity is still lacking. Here we describe studies designed to help define such markers. To this end we have immunized guinea pigs by different methods and monitored the immune response and the corresponding extent of protection against a lethal challenge with anthrax spores. Active immunization was performed by a single injection using one of two methods: (i) vaccination with decreasing amounts of PA and (ii) vaccination with constant amounts of PA that had been thermally inactivated for increasing periods. In both studies a direct correlation between survival and neutralizing-antibody titer was found (r(2) = 0.92 and 0.95, respectively). Most significantly, in the two protocols a similar neutralizing-antibody titer range provided 50% protection. Furthermore, in a complementary study involving passive transfer of PA hyperimmune sera to naive animals, a similar correlation between neutralizing-antibody titers and protection was found. In all three immunization studies, neutralization titers of at least 300 were sufficient to confer protection against a dose of 40 50% lethal doses (LD(50)) of virulent anthrax spores of the Vollum strain. Such consistency in the correlation of protective immunity with anti-PA antibody titers was not observed for antibody titers determined by an enzyme-linked immunosorbent assay. Taken together, these results clearly demonstrate that neutralizing antibodies to PA constitute a major component of the protective immunity against anthrax and suggest that this parameter could be used as a surrogate marker for protection.     

Prevention of immune precipitation by purified components of the alternative pathway

The role of the alternative pathway in complement-mediated prevention of immune precipitation has been investigated by the use of BSA-anti-BSA immune complex (IC) purified components. For immune precipitation to be prevented all six alternative pathway components (C3, factors B D, P, H and I) were required. In the absence of one or both of the control proteins H and I, excessive fluid phase turnover of C3 occurred with precipitation of IC. Kinetic studies showed that in the presence of the control proteins, an initial phase of precipitation occurred, and was followed by a phase of resolubilization of IC. When the efficiency of classical and alternative pathways in the prevention of immune precipitation was compared it was found that the classical pathway proteins were more effective than the alternative pathway components. A reaction mixture containing the components of both pathways was no better than the classical pathway protein alone. 125I-C3 was bound to IC which had been rendered soluble in the presence of classical or alternative pathway components. A molar ratio of two molecules C3b:five molecules IgG was calculated. Other complement components which were bound to IC which had been formed in the presence of serum were C1q, C4, C2, C3, C5, P and H. Factors B and I were not detected. Our findings suggest that the alternative pathway is of secondary importance to the classical pathway in the prevention of immune precipitation.     

Glucocorticoid blockade does not abrogate tumor-induced cachexia

Cancer-induced cachexia is a common manifestation observed in patients with malignancies. Elevated levels of circulating glucocorticoids and interleukin-6 (IL-6) have been observed in cancer patients with cachexia and are implicated as major mediators in this process. The purpose of this study was to investigate the role of circulating glucocorticoid levels as primary mediators in cancer-induced cachexia. We evaluated whether inhibition of glucocorticoids with the receptor antagonist RU-486 could abrogate the detrimental wasting of muscle and adipose tissues seen in a well-characterized murine tumor-induced cachexia model. Mice (12/group) were randomized to control, tumor-bearing, control + vehicle, or tumor-bearing + glucocorticoid receptor antagonist groups. Circulating serum glucocorticoid and IL-6 levels were measured in addition to multiple body composition parameters, such as total body weight, lean body mass, and adipose content. The results of this study indicate a significant physiological alteration in the tumor-bearing host that causes severe and detrimental changes in body composition parameters. Regression analysis demonstrated a significant correlation between increased circulating glucocorticoid levels and alterations in body composition parameters. These observed defects were not abrogated with the administration of a glucocorticoid receptor antagonist. We therefore conclude that the untoward effects of tumor-induced cachexia are not mediated primarily by the peripheral effects of high circulating glucocorticoid levels but may involve a complex interaction with IL-6.     

Biological Evidence for a Neurodevelopmental Model of Pediatric Bipolar Disorder

Bipolar disorder (BD) is a chronic illness with high morbidity and mortality. Pediatric onset BD has a more severe course of illness with higher rates of relapse and psychosocial impairment. Discovering interventions early in the course of BD in youth is paramount to preventing full illness expression and improve functioning in these individuals throughout the lifespan. It is therefore important to understand the mechanisms involved in the development of BD in order to determine which youth are at most risk and provide biological targets for early intervention. To serve this cause, we propose a neurodevelopmental model of BD, based on the existing data that implicate prefrontal - subcortical network dysfunction, caused by pre-existing genetic susceptibility and triggered by pathological reactions to stress and chronic inflammatory processes.     

Mortality in bullous pemphigoid: A systematic review and meta‐analysis of standardized mortality ratios

There are inconsistent data on mortality rates in patients with bullous pemphigoid (BP). Trends in mortality in BP throughout the years are yet to be established. The aim of the present study was to study the mortality in BP patients relative to the general population and to estimate trends in standardized mortality over the past 30 years. We performed a systematic review and meta‐analysis of observational studies in Medline, Embase and Scopus (1823–2017). Reference lists of included studies were also searched for eligible studies. Quality of evidence was assessed using the Newcastle–Ottawa Scale (NOS). A meta‐analysis was performed using random‐effects models to estimate pooled standardized mortality ratios (SMR) with 95% confidence intervals (CI). Meta‐regression models were used to investigate the secular trends in SMR. Ten studies were included covering the period 1960–2015 (1736 patients, 746 deaths). Pooled all‐cause SMR was 3.6 (95% CI, 2.6–5.0). There was no trend in all‐cause SMR across the last three decades (regression coefficient 0.02 [change in logSMR/year]; 95% CI, 0.04–0.08; P = 0.545). In conclusion, there is a 3.6‐fold increased mortality among patients with BP as compared with the age‐matched general population. The excess mortality in BP has not changed significantly over the past 30 years.     

Risk factors for early postpartum hemorrhage (PPH) in the first vaginal delivery,and obstetrical outcomes in subsequent pregnancy

Objective: To investigate risk factors for postpartum hemorrhage (PPH) in vaginal deliveries and the influence of previous PPH on the subsequent pregnancy.

Study design: A retrospective cohort study including first singleton deliveries between the years 1988 and 2012 was performed comparing deliveries with and without PPH. In addition, perinatal outcomes of the subsequent pregnancy were evaluated. Multivariable analysis was performed to control for confounders.

Results: PPH complicated 0.8% of all first vaginal deliveries. Significant risk factors for PPH in vaginal delivery, using a multiple logistic regression model, were: post-term pregnancy, fertility treatments, hypertensive disorders, labor dystocia during the 2nd, and perineal tears grade 2 and 3, respectively. Previous PPH was found to be an independent risk factor for PPH in the subsequent pregnancy. Moreover, previous PPH was found to be a significant risk factor for cesarean section (CS) deliver, to complicate delivery with revision of uterus cavity, anemia, and to require blood transfusion.

Conclusion: Previous PPH poses a risk for recurrent PPH in subsequent delivery and an increased risk for CS. As PPH remains one of the major causes of maternal morbidity, this study strengthens the need for a comprehensive evaluation of prior PPH as a major risk factor for PPH recurrence.     

Bcl-xL protects adult septal cholinergic neurons from axotomized cell death

Bcl-xL suppresses apoptotic cell death induced by diverse stimuli in cell lines in vitro. To examine the mechanism by which axotomized cholinergic neurons die in vivo, lentiviral vectors expressing Bcl-xL, human nerve growth factor (hNGF), or green fluorescent protein were injected into the septum 3 weeks before transection of the fimbria fornix. Three weeks after transection, Bcl-xL- and hNGF-injected animals showed significantly higher numbers of spared cholinergic neurons compared with control (green fluorescent protein) injected animals. These results provide evidence that adult axotomized cholinergic neurons die of apoptotic death that can be prevented by local delivery of hNGF or intracellular delivery of Bcl-xL.     

Treatment of Induced Murine SLE with a Peptide Based on the CDR3 of an Anti-DNA Antibody Reverses the Pattern of Pathogenic Cytokines

A peptide based on the complementarity determining region (CDR) 3 of a pathogenic anti-DNA monoclonal antibody that bears the 16/6 idiotype (Id) was shown previously to be a dominant T-cell epitope in experimental SLE, and to be capable of inhibiting SLE-associated responses. When injected, concomitant with active immunization with the pathogenic human anti-DNA, 16/6 Id + mAb, pCDR3 inhibited the proliferation of LN-derived T cells stimulated in vitro with the 16/6 Id mAb. The inhibition of the specific proliferative responses could be reversed by the addition of exogenous IL-2 to the cultures. Analysis of secreted cytokine profile in supernatants of these cultures demonstrated that pCDR3 treatment reduced significantly the levels of both IL-2 and IFN- &#110 that were elevated further in cells of the 16/6 Id-immunized mice. The CDR3-based peptide was shown here to immunomodulate in vivo experimental SLE, induced by the human anti-DNA 16/6 Id + antibody. The beneficial effects of pCDR3 on the clinical manifestations of SLE were associated with downregulation of the Th1-type (IL-2, IFN- &#110 ) and proinflammatory (TNF- &#102 ) cytokines, whereas the immunosuppressive cytokine TGF- &#103 was up regulated.