Smoking habits and beliefs of future physicians of Pakistan.

OBJECTIVE: To assess the habits, knowledge and attitudes towards smoking among Pakistani medical students. METHODS: A cross-sectional study was conducted from March 2004 to July 2005 at three medical colleges using a World Health Organization (WHO) questionnaire. A total of 1,029 medical students participated in the study. RESULTS: The prevalence of smoking was found to be 11.2%. Smoking was more prevalent among males, hostel residents and first year medical students. Almost half of the smokers had tried to quit smoking. A family member or a friend was considered to be the most likely person to help quit smoking. The majority believed that passive smoking was harmful to health and were generally supportive of legislative measures to reduce tobacco use, such as the restriction of smoking in public places and the prohibition of sale of tobacco to children. Lesser but significant numbers thought that there should be a complete ban on smoking advertisements and that the price of tobacco products should be increased. CONCLUSION: The study shows a high prevalence of tobacco use in future physicians in spite of adequate knowledge about and a satisfactory attitude towards smoking.     

Radiation-induced red cell damage: role of reactive oxygen species

BACKGROUND: Cellular blood components are irradiated to prevent graft- versus-host disease in transfusion recipients at risk for this syndrome. Because gamma radiation can result in the production of reactive oxygen species, the role of reactive oxygen species was investigated in radiation-induced red cell damage. STUDY DESIGN AND METHODS: Whole blood from normal donors was exposed to various doses of t-butyl hydroperoxide (0-1 mM) and/or to gamma-radiation (0-50 Gy). Oxidative damage was assessed by the extent of lipid peroxidation (measured by thiobarbituric acid-reactive substances [TBARS]) and hemoglobin oxidation. Fresh blood was divided into three parts-one initially irradiated and stored, another stored with portions irradiated weekly, and a third stored without irradiation. TBARS and hemoglobin oxidation were measured weekly. RESULTS: As expected, t- butyl hydroperoxide induced TBARS formation and hemoglobin oxidation in a dose-dependent fashion. The gamma-radiation not only increased hemoglobin oxidation and TBARS formation, but also enhanced the t-butyl hydroperoxide effect on red cells. Red cell storage increased TBARS generation and hemoglobin oxidation in a time-dependent fashion. When radiation was administered either initially or after weekly storage, TBARS production and hemoglobin oxidation were increased over that measured in unirradiated paired controls. CONCLUSION: Gamma radiation at clinically used doses increases lipid peroxidation and hemoglobin oxidation in human red cells. The effect of gamma-radiation is accentuated by blood storage and induces damage independent of time of storage.     

Hierarchical pattern of mucosal candida infections in HIV-seropositive women

PURPOSE: Candida is the most common cause of opportunistic mucosal infections in human immunodeficiency virus (HIV)-positive women. We had observed an apparent correlation between the severity of immunodeficiency and the site of mucosal candida infection. The current study was designed to determine whether significant correlations existed between the sites of mucosal candida infection and the degree of immunodeficiency, as determined by subsets of lymphocyte populations. PATIENTS AND METHODS: The subjects in this study are 66 HIV-seropositive women evaluated by members of the Brown University Acquired Immunodeficiency Syndrome (AIDS) Program during the 3-year period, September 1, 1986, through August 30, 1989. All patients had thorough clinical evaluations and relevant laboratory studies at defined intervals. All patients with CD4 lymphocyte counts below 0.2 X 10(9)/L received zidovudine therapy as soon as it became available. After July 1988, all patients with CD4 counts below 0.2 X 10(9)/L received prophylaxis against Pneumocystis carinii pneumonia. All patients were counseled about HIV infection, its modes of transmission, and the early symptoms of opportunistic infections. RESULTS: The longitudinal data demonstrated that candida often infected vaginal mucosa when there was no significant reduction in CD4 lymphocyte counts. Candida infection of the oropharyngeal mucosa was associated with highly significant reductions in CD4 lymphocyte counts. Esophageal candidiasis occurred only with advanced immunodeficiency associated with CD4 counts below 0.1 X 10(9)/L. CONCLUSIONS: Candida mucosal infections occur in a hierarchical pattern in women with HIV infection. Determination of the basis for the differences in susceptibility to candida of the vaginal, oropharyngeal, and esophageal mucosal surfaces will require further studies.     

The epidemiology of motor neurone disease in two counties in the southwest of England

The epidemiology of motor neurone disease (MND) in the counties of Devon and Cornwall in the southwest of England has not previously been studied. A previous study of England and Wales has, however, reported a very high death certification rate of MND in Devon. This study was carried out to establish the prevalence and incidence of MND in Devon and Cornwall and make comparisons with published rates in other populations. We attempted to identify all cases of MND diagnosed in Devon and Cornwall between 2002 and 2007. Case identification was centred on the major hospitals in the two counties and multiple sources of ascertainment were used. All identified cases had their case notes reviewed to establish the diagnosis and classify by type of MND. Point prevalence of MND was established for September 1st, 2007. The overall incidence rate standardised to the 2001 United Kingdom population was 2.52 per 100,000 (95% confidence interval 2.20–2.84). The incidence rate was significantly higher in males (P < 0.001). The estimated male to female incidence ratio was 2.10 (95% CI 1.61–2.73). The crude incidence rate in Cornwall was 3.78 per 100,000 (95% CI 3.03–4.53) and this was significantly higher (P = 0.011) than the rate in Devon, which was 2.61 per 100,000 (95% CI 2.19–3.04). The standardised incidence rate for the study period in Devon was 2.26 per 100,000 (95% CI 1.91–2.60) and in Cornwall it was 3.06 per 100,000 (95% CI 2.44–3.68). The overall standardised point prevalence rate was 5.66 per 100,000 (95% CI 4.49–6.83). The incidence rate of MND in our study is similar to reported findings in large prospective studies of the disease. There is a significant difference between the incidence rates in Devon and Cornwall. There is a need to establish a prospective MND Register to accurately document the epidemiological characteristics of the disease in the two counties.     

J1‐31 protein expression in astrocytes and astrocytomas

J1‐31 is one of the astrocytic proteins, the expression of which has not been evaluated in astrocytomas. In the present study, we studied the expression of J1‐31 protein in astrocytes and astrocytomas in comparison with GFAP, p53 and Ki‐67. Materials consisted of formalin‐fixed paraffin‐embedded tissue specimens that included five cases of normal brain, 17 of gliosis, 15 of pilocytic astrocytoma (WHO grade I), 26 of low‐grade diffuse astrocytoma (WHO grade II), four of anaplastic astrocytoma (WHO grade III), and eight of glioblastoma (WHO grade IV). GFAP was highly expressed in all specimens examined. The anti‐J1‐31 antibody exhibited strong cytoplasmic staining of reactive gliosis in 17/17 (100%) cases with a higher intensity of staining than that observed in the adjacent normal astrocytes. The antibody showed reactivity with tumor cells in 12/15 (80%) cases of pilocytic astrocytoma, although intensity of staining was generally weaker and more focal than observed in reactive gliosis. J1‐31‐positive tumor cells were detected in only 9/26 (35%) cases of the low‐grade diffuse astrocytoma and none of the cases of anaplastic astrocytoma and glioblastoma. Increasing Ki‐67 indices paralleled advancing tumor grades. p53 protein was expressed more commonly in infiltrating astrocytomas compared to pilocytic astrocytoma. In conclusion, down‐regulation of J1‐31 expression correlates with advancing grade of astrocytomas. The result suggests this protein plays some role in astrocytes that is progressively lost in malignant progression. The anti‐J1‐31 antibody may help further our understanding of astrocytes in disease and may be useful as an aid in the pathologic diagnosis of astrocytic lesions.     

Telomere repeat binding factor 2 interacts with base excision repair proteins and stimulates DNA synthesis by DNA polymerase beta

The ends of linear chromosomes are capped and protected by protein-DNA complexes termed telomeres. Consequences of telomere dysfunction include genomic instability that can contribute to neoplastic transformation and progression. Telomere binding proteins interact with numerous proteins involved in DNA repair, underscoring the importance of regulating DNA repair pathways at telomeres. Telomeric DNA is particularly susceptible to oxidative damage, and such damage is repaired primarily via the base excision repair (BER) pathway. Using a screen for potential interactions between telomere repeat binding factor 2 (TRF2) and proteins involved in BER of oxidized bases in vitro, we found that TRF2 physically bound DNA polymerase beta (Pol beta) and flap endonuclease 1 (FEN-1). The interactions with endogenous proteins in human cell extracts were confirmed by coimmunoprecipitation experiments. The primary binding sites for both Pol beta and FEN-1 mapped to the TRF2 NH2-terminal and COOH-terminal domains. We further tested the ability of TRF2 to modulate BER protein partners individually on a variety of substrates in vitro. TRF2 stimulated Pol beta primer extension DNA synthesis on telomeric and nontelomeric primer/template substrates, resulting in up to a 75% increase in the proportion of longer products. TRF2 also stimulated Pol beta strand displacement DNA synthesis in reconstituted BER reactions and increased the percent of long-patch BER intermediates on both telomeric and nontelomeric substrates. Potential roles of TRF2 in cooperation with BER proteins for DNA repair pathways at telomeres, as well as other genomic regions, are discussed.     

Identification of a cell-surface glycoprotein associated with normal mammary and extramammary epithelial cells.

The goal of the study was to identify any normal genes that may become inactivated in malignant cells, with associated modifications or loss of gene products. Consequently, attempts were made to identify such products by generating monoclonal antibodies using an immune tolerisation-immunisation procedure. Using such a technique, a plasma membrane-associated glycoprotein with an apparent molecular weight of 92 kDa was identified. The glycoprotein was termed luminal epithelial antigen (LEA.92). The pattern of expression of LEA.92 was demonstrated by an indirect immunostaining technique. Using an in vitro model system representing various stages of breast oncogenesis, LEA.92 was detected on normal or immortalised mammary epithelial cell (MEC) lines which were dependent on epidermal growth factor (EGF) and anchorage formation for growth and non-tumorigenic in nude mice. In contrast, LEA.92 was undetectable on oncogenically transformed or established lines of mammary carcinoma cell lines which were independent of EGF or anchorage formation for growth and were highly tumorigenic. The results appear to suggest a correlation between the down-regulation of LEA.92 and the development of tumorigenicity in malignant MEC lines. Furthermore, the patterns of expression of LEA.92 on breast cells in tissue mirrored those of breast epithelial cells in cell cultures. LEA.92 was detected on the surface of normal but not malignant epithelial cells, which included breast, cervix, colon, lung, pancreas and stomach. LEA.92 appeared to be distinct from receptor for epidermal growth factor, antigens associated with milk fat globule membrane and the family of epithelium-specific keratins.     

LEA-135 expression: its association with a lower risk of recurrence and increased overall survival of patients with lymph node-positive primary invasive breast cancer

A retrospective study was undertaken to determine and compare the prognostic significance of LEA-135 protein expression by immunohistochemistry with other prognostic pathological parameters, with respect to recurrence and overall survival. This study was conducted in freshly-frozen tissue sections from a cohort of 367 patients having primary invasive breast cancer, with axillary lymph node metastasis. The association of LEA-135 expression was compared with estrogen and progesterone receptor status, segmentectomy or radical mastectomy and hormonal therapy or chemotherapy in terms of recurrence or disease-free survival. Pathologic parameters including tumor size, histological tumor type and histological grade, as well as age of patients at the time of initial diagnosis, and the treatments, together with a median follow-up of 8.8 years were contemplated for the study. Among these parameters, tumor size and histological grade were individually and significantly associated with an increased probability of recurrence (log rank p<0.001 in both cases) and short survival (log ranks p<0.001 and p=0.002, respectively), whereas age was only significantly associated with an increased probability of recurrence (log rank p=0.002) by univariate analysis. By multivariate analysis, both tumor size and histological grade remained statistically significant for recurrence (log rank p<0.001 and p=0.013, respectively) and overall survival (log ranks p<0.001 and p=0.016, respectively). Among the prognostic biomarkers, both ER and PR expression were associated with a decreased rate of recurrence (log ranks p<0.001 and p=0.008, respectively) and overall survival (log ranks p<0.001 and p=0.002, respectively) by univariate analysis. By multivariate analysis, only the ER expression remained significantly associated with a decreased recurrence and increased overall survival (log ranks p=0.023 and p=0.002, respectively). Patients with high (>50% positive cells) or moderate (5-50% positive cells) number of LEA-135-positive cells had a lower probability (46%) of recurrence at 10 years after surgery compared to 76% in LEA-135-negative patients (log rank p<0.001) by univariate analysis. Moreover, the probability of overall survival was higher in patients with high or moderate expression of LEA-135 (46% and 47%, respectively) compared to LEA-135-negative patients (24%) by univariate analysis (log rank p=0.009). By multivariate analysis, the association remained statistically significant for recurrence (log rank p<0.001) and survival (log rank p=0.002). However, there was no significant association between LEA-135 and any of the pathological parameters, age, hormone receptor status, the mode of surgery or the form of therapy (chemo- and/or hormonal) received by this cohort of patients. The results show that an improved prognosis was directly associated with the density of LEA-135-positive cancer cells, while loss of LEA-135 expression was associated with an aggressive phenotype of cancer cells during breast cancer progression. Thus, LEA-135 expression can be implicated as a significant and independent biomarker to identify and distinguish high- from low-risk patients with lymph node-positive invasive breast cancer for an aggressive treatment. Moreover, according to the present results, LEA-135 expression appears to be associated with the tumor cells that have retained certain normal biological characteristics, leading to their lack of aggressiveness and hence a better prognosis.     

Characterization of a cell surface molecule expressed on B-lymphocytes and Hodgkin's cells.

An antigen specifically expressed on the surface of plasma membrane of B-lymphocytes and Reed-Sternberg cells was identified using a newly developed monoclonal antibody produced by immunization by BALB/c mouse with a Hodgkin's cell line (HDLM-3). The antibody was termed anti-BLA.36 (B lymphocyte antigen.36) to indicate its predominant reactivity and the molecular weight of the corresponding antigen. By using immunoperoxidase techniques, expression of BLA.36 was detected on Hodgkin's, B-, and pre-B-cell lines, but not on other hematopoietic, melanoma, or carcinoma cell lines. In normal tissues, BLA.36 was detectable predominantly on cells in the germinal center and mantle zone of reactive follicles in lymph nodes and spleen. In hematopoietic malignancy, BLA.36 was detectable on the surface of Reed-Sternberg cells, mononuclear Hodgkin's cells, and also on malignant cells of B-cell lineage. Under these conditions, T-lymphocytes, histiocytes, granulocytes, macrophages, stromal cells in lymphoid tissue, and both normal and neoplastic epithelial cells were consistently negative for the expression of the antigen, with the single exception of a variable proportion of Kupffer cells in normal liver. Biochemical and immunological analyses indicate that BLA.36 is distinct from previously identified antigens of hematopoietic cell lineage, including CD20 and CD75 (LN2) which have similar molecular weights. When BLA.36-positive cell lines were cultured in the presence of the antibody, cell growth was adversely affected. Such an effect was eliminated by removal of the antibody from the culture, suggesting a possible growth-related function of the antigen. Anti-BLA.36 may serve as a probe to study growth-related functions of the corresponding antigen during normal growth of the B-lymphocyte, as well as in the neoplastic proliferations occurring in Hodgkin's disease and antigen-positive B-cell lymphomas. Finally, the antibody has already demonstrated its usefulness for the identification of Reed-Sternberg and Hodgkin's cells, and also normal and malignant B-lymphocytes in frozen as well as formalin- or B5-fixed/paraffin-embedded tissue sections.