Enhancement of epidermal growth factor receptor expression on glioma cells by recombinant tumor necrosis factor α

Summary Recombinant tumor necrosis factor (rTNF; optimal dose 1000 U/ml) significantly increased the density of epidermal growth factor receptor (EGF-R) in three of four glioma cell lines in culture as determined by binding analysis of anti-EGF-R monoclonal antibody (mAb) 425. Since enhancement of EGF-R expression by rTNF- was inhibited when cells were treated with the protein synthesis inhibitor cycloheximide, the effects of rTNF may be protein-synthesis-dependent. The dose of rTNF that was optimal for up-regulation of EGF-R on glioma cells did not inhibit the growth of these cells.¹²⁵I-labeled mAb 425 lysed glioma cells in culture following its internalization into the cells. After glioma cells had been treated with rTNF, the growth-inhibitory effects of the mAb were significantly enhanced, probably a reflection of the increase in EGF-R density on the tumor cell surfaces. The rTNF effects were specific to the EGF-R and did not affect unrelated glioma-associated antigens. In our previous clinical trials,¹²⁵I-labeled mAb 425 showed immunotherapeutic effects in glioma patients. The present study provides the basis for considerations of combined immunotherapy of glioma patients with¹²⁵I-labeled mAb 425 and rTNF.     

Androgen metabolism in male and female breast tissue

Incubation studies have been carried out using normal breast tissue and breast tissue from patients with gynecomastia, mammary dysplasia and breast carcinoma to determine the pattern of androstenedione metabolism. All tissues formed estrone (E₁) and testosterone (T) in all incubations. Estradiol (E₂) was isolated in incubations of tissue from 1 to 6 patients with mammary dysplasia, 5 of 6 patients with gynecomastia and in all incubations with normal and carcinoma tissue. Estrone formation was lowest in mammary dysplasia and gynecomastia, and higher in apparently normal breast tissue. The greatest E₁ formation was found in incubations with breast carcinoma tissue, although there was considerable variation within this tissue group. Estradiol formation was low in all tissues, with the highest conversion rates in carcinoma tissue. Testosterone formation in carcinoma tissue was greater than in mammary dysplasia or gynecomastia, but similar to apparently normal tissue. These results indicate that breast tissue from different pathological states varies in its capacity to aromatize androstenedione (A) to estrogenic products and to convert it to other androgens. They have also shown that the pattern of metabolism is distinctive for the nature of the pathological abnormality.     

A Systematic Review of the Relationship between Blood Loss and Clinical Signs

Introduction

This systematic review examines the relationship between blood loss and clinical signs and explores its use to trigger clinical interventions in the management of obstetric haemorrhage.

Methods

A systematic review of the literature was carried out using a comprehensive search strategy to identify studies presenting data on the relationship of clinical signs & symptoms and blood loss. Methodological quality was assessed using the STROBE checklist and the general guidelines of MOOSE.

Results

30 studies were included and five were performed in women with pregnancy-related haemorrhage (other studies were carried in non-obstetric populations). Heart rate (HR), systolic blood pressure (SBP) and shock index were the parameters most frequently studied. An association between blood loss and HR changes was observed in 22 out of 24 studies, and between blood loss and SBP was observed in 17 out of 23 studies. An association was found in all papers reporting on the relationship of shock index and blood loss. Seven studies have used Receiver Operating Characteristic Curves to determine the accuracy of clinical signs in predicting blood loss. In those studies the AUC ranged from 0.56 to 0.74 for HR, from 0.56 to 0.79 for SBP and from 0.77 to 0.84 for shock index. In some studies, HR, SBP and shock index were associated with increased mortality.

Conclusion

We found a substantial variability in the relationship between blood loss and clinical signs, making it difficult to establish specific cut-off points for clinical signs that could be used as triggers for clinical interventions. However, the shock index can be an accurate indicator of compensatory changes in the cardiovascular system due to blood loss. Considering that most of the evidence included in this systematic review is derived from studies in non-obstetric populations, further research on the use of the shock index in obstetric populations is needed.     

Major Cardiovascular Risk Factors in Latin America: A Comparison with the United States. The Latin American Consortium of Studies in Obesity (LASO)

Background

Limited knowledge on the prevalence and distribution of risk factors impairs the planning and implementation of cardiovascular prevention programs in the Latin American and Caribbean (LAC) region.

Methods and Findings

Prevalence of hypertension, diabetes mellitus, abnormal lipoprotein levels, obesity, and smoking were estimated from individual-level patient data pooled from population-based surveys (1998–2007, n = 31,009) from eight LAC countries and from a national survey of the United States (US) population (1999–2004) Age and gender specific prevalence were estimated and age-gender adjusted comparisons between both populations were conducted. Prevalence of diabetes mellitus, hypertension, and low high-density lipoprotein (HDL)-cholesterol in LAC were 5% (95% confidence interval [95% CI]: 3.4, 7.9), 20.2% (95% CI: 12.5, 31), and 53.3% (95% CI: 47, 63.4), respectively. Compared to LAC region’s average, the prevalence of each risk factor tended to be lower in Peru and higher in Chile. LAC women had higher prevalence of obesity and low HDL-cholesterol than men. Obesity, hypercholesterolemia, and hypertriglyceridemia were more prevalent in the US population than in LAC population (31 vs. 16.1%, 16.8 vs. 8.9%, and 36.2 vs. 26.5%, respectively). However, the prevalence of low HDL-cholesterol was higher in LAC than in the US (53.3 vs. 33.7%).

Conclusions

Major cardiovascular risk factors are highly prevalent in LAC region, in particular low HDL-cholesterol. In addition, marked differences do exist in this prevalence profile between LAC and the US. The observed patterns of obesity-related risk factors and their current and future impact on the burden of cardiovascular diseases remain to be explained.     

Chloroquine induces activation of nuclear factor-kappaB and subsequent expression of pro-inflammatory cytokines by human astroglial cells

Chloroquine, an antimalarial lysosomotropic base, is known for its anti-inflammatory effects and therefore used for treatment of autoimmune diseases. Given its anti-inflammatory effects, it has been under clinical trials to modify neurodegenerative processes. In this study, we examined whether chloroquine has an anti-inflammatory effect in the CNS by determining the in vitro effects of chloroquine on LPS-induced expression of cytokines by glial cells. We observed that (i) chloroquine augmented LPS-induced expression of pro-inflammatory cytokines such as lymphotoxin (LT)-beta, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1alpha, IL-1beta and IL-6 in human astroglial cells, while the same treatment suppressed LPS-induced expression of cytokines in monocytic and microglial cells; (ii) chloroquine alone induced expression of pro-inflammatory cytokines in a dose- and time-dependent manner in astroglial cells; (iii) other lysosomotropic agents such as ammonium chloride and bafilomycin A1 had minimal effects on cytokine expression; and (iv) chloroquine induced the activation of nuclear factor-kappa B in astroglial cells, which is a required component of chloroquine induction of cytokines. These results suggest that chloroquine may evoke either anti- or pro-inflammatory responses in the CNS depending on the cellular context.     

Suppressor of cytokine signaling 1 inhibits cytokine induction of CD40 expression in macrophages

CD40 is a type I membrane-bound molecule belonging to the TNFR superfamily that is expressed on various immune cells including macrophages and microglia. The aberrant expression of CD40 is involved in the initiation and maintenance of various human diseases including multiple sclerosis, arthritis, atherosclerosis, and Alzheimer's disease. Inhibition of CD40 signaling has been shown to provide a significant beneficial effect in a number of animal models of human diseases including the aforementioned examples. We have previously shown that IFN-gamma induces CD40 expression in macrophages and microglia. IFN-gamma leads to STAT-1alpha activation directly and up-regulation of NF-kappaB activity due to the secretion and subsequent autocrine signaling of TNF-alpha. However, TNF-alpha alone is not capable of inducing CD40 expression in these cells. Suppressor of cytokine signaling 1 protein (SOCS-1) is a cytokine-inducible Src homology 2-containing protein that regulates cytokine receptor signaling by inhibiting STAT-1alpha activation via a specific interaction with activated Janus kinase 2. Given the important role of CD40 in inflammatory events in the CNS as well as other organ systems, it is imperative to understand the molecular mechanisms contributing to both CD40 induction and repression. We show that ectopic expression of SOCS-1 abrogates IFN-gamma-induced CD40 protein expression, mRNA levels, and promoter activity. Additionally, IFN-gamma-induced TNF-alpha secretion, as well as STAT-1alpha and NF-kappaB activation, are inhibited in the presence of SOCS-1. We conclude that SOCS-1 inhibits cytokine-induced CD40 expression by blocking IFN-gamma-mediated STAT-1alpha activation, which also then results in suppression of IFN-gamma-induced TNF-alpha secretion and subsequent NF-kappaB activation.     

Direct and quantitative single-cell analysis of human immunodeficiency virus type 1 reactivation from latency

The ability of human immunodeficiency virus type 1 (HIV-1) to establish latent infections in cells has received renewed attention owing to the failure of highly active antiretroviral therapy to eradicate HIV-1 in vivo. Despite much study, the molecular bases of HIV-1 latency and reactivation are incompletely understood. Research on HIV-1 latency would benefit from a model system that is amenable to rapid and efficient analysis and through which compounds capable of regulating HIV-1 reactivation may be conveniently screened. We describe a novel reporter system that has several advantages over existing in vitro systems, which require elaborate, expensive, and time-consuming techniques to measure virus production. Two HIV-1 molecular clones (NL4-3 and 89.6) were engineered to express enhanced green fluorescent protein (EGFP) under the control of the viral long terminal repeat without removing any viral sequences. By using these replication-competent viruses, latently infected T-cell (Jurkat) and monocyte/macrophage (THP-1) lines in which EGFP fluorescence and virus expression are tightly coupled were generated. Following reactivation with agents such as tumor necrosis factor alpha, virus expression and EGFP fluorescence peaked after 4 days and over the next 3 weeks each declined in a synchronized manner, recapitulating the establishment of latency. Using fluorescence microscopy, flow cytometry, or plate-based fluorometry, this system allows immediate, direct, and quantitative real-time analysis of these processes within single cells or in bulk populations of cells. Exploiting the single-cell analysis abilities of this system, we demonstrate that cellular activation and virus reactivation following stimulation with proinflammatory cytokines can be uncoupled.