Lymphocytotoxins in infectious mononucleosis: a non-cytotoxic effect on their cytotoxicity in vitro

The lymphocytotoxic activity (LCA) of sera from patients with infectious mononucleosis (IM) was tested against lymphocytes under various experimental conditions. Firstly, lymphocytes from 11 healthy donors were preincubated with pools of normal human sera (NHS) or IM sera at 37°C and then tested for (a) reactivity with the same IM sera in a standard lymphocytotoxin assay at 15°C; (b) rosetting with various sheep erythrocyte (E) preparations (E, EA and EAC) and (c) stimulation by non-specific activators (phytohaemagglutinin, pokeweed mitogen and concanavalin A). These experiments showed that preincubation of normal cells with IM sera caused significant reduction in subsequent lymphocyte killing at 15°C (P<0·01) compared to unincubated cells or those preincubated with pooled NHS. There was no change in the binding of E, EA and EAC or mitogen stimulation following incubation. Culture of preincubated lymphocytes in lymphocytotoxin-free medium for 24 hr did not restore LCA at 15°C. Secondly, a pool of normal lymphocytes was incorporated into media containing either 2,4-dinitrophenol or sodium azide and tested for LCA against 11 acute IM sera and two NHS at both 15 and 37°C. No significant change in cell killing was observed at 15°C in the presence of these inhibitors, but there was a significant return of LCA at 37°C. Finally, normal lymphocytes and cells from two patients with IM were cultured at 37°C in lymphocytotoxin-free medium to determine the role of down-regulation of lymphocyte surface receptors in reducing autolymphocytotoxicity during the acute phase of the illness. There was no change in cell killing by IM sera after culture for 24 hr. These experiments show that lymphocytotoxic sera from patients with infectious mononucleosis interact with normal lymphocytes at 37°C without causing cell killing. This interaction caused a change in surface-binding characteristics that was not reversed by culture in ligand-free medium for 24 hr. Studies using metabolic inhibitors suggested that the failed lymphocytotoxicity at 37°C resulted, at least in part, from lymphocyte metabolism, although this did not inhibit the reaction between cytotoxic material and the lymphocyte surface.     

Cytomegalovirus detection by biotinylated DNA probes

Clinical specimens from 317 patients suspected of cytomeglovirus infection were examined by immunofluorescence (IF) using monoclonal antibodies and by a biotinylated DNA probe kit after cell culture isolation. Of the 317 samples, 68 were positive by culture isolation. Of these 67 were IF positive when the cytopathic effect (CPE) was 1⁺ or less, whereas 56 gave positive results with DNA probes when the CPE was 2⁺. A further 83 specimens were examined directly by immunoperoxidase histopathology (IHP), IF and the DNA probe kit: 26 of these were positive by IHP examination, 25 by IF and only 6 by DNA probes. The sensitivity of the DNA probe kit was not satisfactory when the clinical tissue specimens were directly examined. However, the sensitivity improved considerably to 82% if the specimens were propagated first in cell culture. The IF method detected the virus before and after cell culture isolation equally well (96%–98.5%). Compared to the IF method, the DNA probe kit is costly and requires more labor and time.This paper was presented in part at the 88th annual meeting of the American Society for Microbiology, Miami Beach, FL, USA, 1988     

Depression,sleeping pattern,and suicidal ideation among medical students in Bangladesh: a cross-sectional pilot study

Journal of Public Health - Depression is a major morbidity and the most common mental disorder among the medical students in medical schools globally. Undergraduate students suffer stress more due...     

A qualitative exploration of barriers to HIV prevention,treatment and support: Perspectives of transgender women and service providers

Transgender (trans) women experience barriers to access to HIV care, which result in their lower engagement in HIV prevention, treatment and support relative to cisgender people living with HIV. Studies of trans women's barriers to HIV care have predominantly focused on perspectives of trans women, while barriers are most often described at provider, organisation and/or systems levels. Comparing perspectives of trans women and service providers may promote a shared vision for achieving health equity. Thus, this qualitative study utilised focus groups and semi-structured interviews conducted 2018–2019 to understand barriers and facilitators to HIV care from the perspectives of trans women (n = 26) and service providers (n = 10). Barriers endorsed by both groups included: (a) anticipated and enacted stigma and discrimination in the provision of direct care, (b) lack of provider knowledge of HIV care needs for trans women, (c) absence of trans-specific services/organisations and (d) cisnormativity in sexual healthcare. Facilitators included: (a) provision of trans-positive trauma-informed care, (b) autonomy and choice for trans women in selecting sexual health services and (c) models for trans-affirming systems change. Each theme had significant overlap, yet nuanced perspective, between trans women and service providers. Specific recommendations to improve HIV care access for trans women are discussed. These recommendations can be used by administrators and service providers alike to work collaboratively with trans women to reduce barriers and facilitators to HIV care and ultimately to achieve health equity for trans women.     

Genetic variation associated with chromosomal aberration frequency: A genome-wide association study

Chromosomal aberrations (CAs) in human peripheral blood lymphocytes (PBL) measured with the conventional cytogenetic assay have been used for human biomonitoring of genotoxic exposure for decades. CA frequency in peripheral blood is a marker of cancer susceptibility. Previous studies have shown associations between genetic variants in metabolic pathway, DNA repair and major mitotic checkpoint genes and CAs. We conducted a genome-wide association study on 576 individuals from the Czech Republic and Slovakia followed by a replication in two different sample sets of 482 (replication 1) and 1288 (replication 2) samples. To have a broad look at the genetic susceptibility associated with CA frequency, the sample sets composed of individuals either differentially exposed to smoking, occupational/environmental hazards, or they were untreated cancer patients. Phenotypes were divided into chromosome- and chromatid-type aberrations (CSAs and CTAs, respectively) and total chromosomal aberrations (CAtot). The arbitrary cutoff point between individuals with high and low CA frequency was 2% for CAtot and 1% for CSA and CTA. The data were analyzed using age, sex, occupation/cancer and smoking history as covariates. Altogether 11 loci reached the P-value of 10⁻⁵ in the GWAS. Replication 1 supported the association of rs1383997 (8q13.3) and rs2824215 (21q21.1) in CAtot and rs983889 (5p15.1) in CTA analysis. These loci were found to be associated with genes involved in mitosis, response to environmental and chemical factors and genes involved in syndromes linked to chromosomal abnormalities. Identification of new genetic variants for the frequency of CAs offers prediction tools for cancer risk in future. Environ. Mol. Mutagen. 60:17–28, 2019. © 2018 Wiley Periodicals, Inc.     

Ellagic acid ameliorates cisplatin induced hepatotoxicity in colon carcinogenesis

The clinical application of cisplatin (CP), one of the most extensively used antineoplastic drug, is restricted by its numerous side effects. CP's antitumor potential resides in the free generation of reactive oxygen species leading to oxidative stress. This stress is a source of the side effects associated with its use. Ellagic acid (EA), a polyphenol is known to possess multiple health benefits owing to its antioxidant properties. EA is largely metabolized by the colon microbiota of different mammals and therefore was a polyphenol of choice in the present study. The present study was thus carried out to explore the protective potential of EA on CP induced hepatotoxicity in colon tumor bearing mice. The administration of EA (10 mg/kg bwt po daily for 6 weeks) significantly ameliorated the toxicity caused by CP (5 mg/kg bwt ip once a week for 4 weeks). Activities of liver marker enzymes and lactate dehydrogenase were brought back to normal. EA cotreatment also led to a marked reduction in the extent of peroxidative damage to liver tissue as was evident from the improvement in the histopathological changes observed and FT‐IR analysis. The present study, therefore, suggests that the administration of EA reduces the CP‐induced hepatotoxicity, thereby emerging out as a potential candidate for chemopreventive action.     

Aloe vera affects changes induced in pulmonary tissue of mice caused by cigarette smoke inhalation

This study was undertaken to determine the influence of Aloe vera (AV) on changes induced in pulmonary tissue of cigarette smoke (CS) inhaling mice. CS inhalation for 4 weeks caused pulmonary damage as evident by histoarchitectural alterations and enhanced serum and tissue lactate dehydrogenase (LDH) activities. CS inhalation also led to increased mucin production as revealed by mucicarmine and Alcian Blue‐Periodic Acid Schiff (AB‐PAS) staining. Studies on bronchoalveolar lavage fluid (balf) of CS exposed animals revealed structural changes in phospholipids and increase in surface tension when compared with control counterparts. These changes were accompanied by enhanced nitric oxide (NO) levels, citrulline levels, peroxidative damage, and differential modulation of antioxidant defense system. AV administration (seven weeks, 500 mg/kg b.w. daily) to CS inhaling mice led to modulation of CS induced pulmonary changes as revealed by lesser degree of histoarchitectural alterations, lesser mucin production, decreased NO levels, citrulline levels, peroxidative damage, and serum LDH activity. AV treatment to CS inhaling mice was associated with varying response to antioxidant defense system, however balf of CS + AV treated animals did not exhibit appreciable changes when compared with that of CS exposed animals. These observations suggest that AV has the potential to modulate CS induced changes in the pulmonary tissue which could have implications in management of CS associated pulmonary diseases, however, further investigations are required to explore its complete mechanism of action. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 999–1013, 2015.     

Correlation of Ki-67, p53, and Adnab-9 immunohistochemical staining and ploidy with clinical and histopathologic features of severely dysplastic colorectal adenomas

Variations of Ki-67, p53, and Adnab-9 monoclonal antibody reactions in colonic adenomas may be associated with colonic cancer risk. We studied the predictive value of these markers for adverse behavior in severely dysplastic colorectal adenomas, such as an associated carcinoma, multiplicity of adenomas, and subsequent development of adenomas. For this purpose we compared the clinical, gross, and histologic characteristics of highly dysplastic index polyps in 42 patients with Ki 67, p53, and Adnab-9 immunostaining and other molecular markers. Polyps were removed endoscopically, and severely dysplastic polyps were stained immunohistochemically with Ki-67, Adnab-9, and p53 protein by the avidin biotin conjugate (ABC) technique. Quantitative DNA (QDNA) was analyzed by computer-assisted image analysis. Ki-67 immunohistochemistry showed reversal of normal distribution of nuclear staining from the normal basal position to the upper third of the colonic crypts. This abnormality of immunostaining in dysplastic adenomas was the earliest detected by the panel we used. A statistically significant correlation was seen between invasiveness of carcinoma in the index polyp and polyp size (P = 0.003), sessile morphology (P = 0.037), and villous or tubulovillous histology (P = 0.019). In the index adenoma, p53 positivity was correlated with multiplicity at initial examination (P = 0.053), villous histology (P = 0.053), invasiveness of carcinoma (P < 0.003), and recurrence of colorectal adenomas (P = 0.025). Although p53 positivity and aneuploidy were correlated with invasiveness of carcinoma in the index polyp (P = 0.025), Adnab-9 positivity was not. However, Adnab-9 positivity in the index polyp was associated with multiplicity of adenomas (P = 0.04) as well as recurrence of adenomas (P < 0.024). In conclusion, in addition to the morphologic and histologic markers already known, Ki-67, Adnab-9 antibody, and p53 protein may be prognostic indicators useful in follow-up of patients with severely dysplastic colorectal adenomas. Adnab-9 antibody may identify a field defect in above-average-risk adenoma-bearing patients.