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Biomedical subjects

J Weinberg

Publications and source records attributed to J Weinberg.

At least 91 records · Page 5Linked to original sources
PubMed1995

Role of natural killer cells in psychosocial stressor-induced changes in mouse mammary tumor growth.

We have shown that social housing conditions affect the growth rate of the androgen-responsive Shionogi mouse mammary tumor (SC115) and differentially stimulate splenic natural killer (NK) cell activity. Mice reared in a social group and then singly housed (GI) following tumor cell injection have increased tumor growth rates and increased NK cell activity, whereas mice reared individually and then group housed following tumor cell injection have decreased tumor growth rates and decreased NK cell activity compared to that in mice remaining in their rearing group. The present study was undertaken to determine whether NK cells are involved in mediating the effects of social housing conditions on SC115 tumor growth rates. We demonstrate that the presence of the SC115 tumor significantly stimulates the activity of NK cells at the tumor site in the first 7 days after tumor cell injection, and that, consistent with the data on splenic NK cells, mice of the GI group (largest tumors) have significantly greater levels of NK cell activity than mice reared individually and then group housed (smallest tumors). We further demonstrate that in mice of the GI group, in vivo stimulation of NK cell activity by polyinosinic:polyCMP correlates with a corresponding increase in tumor growth rate. These findings suggest that NK cell activity may play a role in mediating the increased tumor growth rate observed in mice of the GI housing condition.

Androgens↗
PubMed1995

Effects of amlodipine on 24-hour ambulatory blood pressure profiles, electrocardiographic monitoring, and left ventricular mass and function in black patients with very severe hypertension.

In a 3-month, open-label study, 54 consecutive black patients with very severe hypertension were treated with amlodipine. Very severe hypertension was defined as an average sitting diastolic blood pressure (BP) > or = 115 mmHg and < or = 140 mmHg as a mean of 10 readings over a 30-minute period using an automatic BP measuring device and a mean 24-hour diastolic ambulatory blood pressure (ABP) > or = 110 mmHg and < or = 140 mmHg). Serial changes in 24-hour ABP and electrocardiographic monitoring, left ventricular (LV) mass index, and LV systolic function were evaluated. Mean 24-hour ABP was reduced from 181 +/- 14/119 +/- 6 to 140 +/- 15/92 +/- 9 mmHg at 3 months (P < 0.0001). Target BP (mean 24-hour diastolic ABP < 90 mmHg) was achieved in 35% of the patients. The reduction in BP was sustained for 24 hours after drug administration. Simultaneous BP measurements using the automatic BP measuring device were significantly different from the ABP measurements before and after treatment, suggesting a marked "white coat" pressor effect. At baseline, frequent or complex ventricular arrhythmias (> 30 ventricular extrasystoles per hour, ventricular couplets) were present in 2 (4%) patients, with no significant change after treatment. Left ventricular mass index regressed from 140 +/- 50 to 111 +/- 30 g/m2 at 3 months (P < 0.03); LV performance was not adversely affected. Adverse effects were few and tended to disappear during the treatment period. All of the clinical laboratory parameters tested remained unchanged. In this group of patients, treatment with amlodipine showed a marked and sustained antihypertensive action as demonstrated by 24-hour ABP monitoring, and was well tolerated and associated with LV mass regression without adverse effect on systolic cardiac function. Further, a low rate of complex ventricular arrhythmias was documented.

Adult↗
PubMed1995

Public health, epidemiology and war.

The delivery of humanitarian aid in wartime is difficult. However, it is essential that aid is provided in the most effective manner possible, targeted on those most in need whilst minimizing waste. Furthermore the delivery of aid should be sensitive to the future needs of the communities in conflict. This requires information on the needs of the vulnerable population. There is little experience of collecting data on the impact of war on a civilian population. The war in Bosnia disrupted surveillance of communicable disease. The local authorities were assisted by the World Health Organization in re-establishing surveillance. The data generated was valuable in planning interventions to minimise the possibility of major outbreaks of infection, reduce the impact of infectious disease and in guiding the humanitarian aid effort. The experience described suggests that public health surveillance of the civilian population in wartime is possible and useful. Besides the need for planning, the public health doctor in wartime has a role as an advocate for those suffering; this function can be carried out much more effectively if it is based on objective data collection rather than hearsay.

Bosnia and Herzegovina↗
PubMed1995

Effects of prenatal ethanol exposure and stress in adulthood on lymphocyte populations in rats.

The present study was undertaken to assess the possible interactive effects of prenatal ethanol exposure and stress in adulthood on lymphocyte populations in rat offspring, and to examine differential vulnerability of males and females to these challenges. Male and female offspring from prenatal ethanol-exposed (E), pair-fed, and ad libitum-fed control conditions were exposed to a 3-week chronic intermittent stress regimen in adulthood. Animals were exposed to two of six different stressors daily, one each at random times in the morning and afternoon, with the same pair of stressors being repeated every 4 days. Following the 3-week stress period, lymphocytes from four compartments (peripheral blood, spleen, thymus, and cervical lymph nodes) were analyzed for expression of differentiation antigens. Data demonstrate that, whereas a number of the effects of prenatal ethanol on lymphocyte populations appeared to be nutritionally mediated, the additional challenge of exposure to stressors differentially affected animals exposed to ethanol prenatally and appeared to have effects primarily in male offspring. Stressed E males had a greater reduction in the number of pan T-cells in the thymus and peripheral blood, compared with nonstressed E males, but showed an increased peripheral blood pan T-antigen expression. Stressed E males also had reduced numbers of peripheral blood CD4+ T cells compared to nonstressed E males [corrected].(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effects of muscle-to-electrode distance on the human diaphragm electromyogram.

It has been suggested that esophageal recordings of the diaphragm electromyogram (EMGdi) are influenced by changes in chest wall configuration. Whether the changes are of physiological or artifactual origin is unclear. For example, the distance between the esophageal electrode and the diaphragm is likely to alter with chest wall configuration and may lead to misinterpretations of EMGdi. The aims of this study were 1) to evaluate and quantify the effect of the muscle-to-electrode (ME) distance filter on EMGdi, as obtained with a multiple-array esophageal electrode, 2) to take advantage of the ME distance filter to locate the position of the diaphragm with respect to the electrode, and 3) to evaluate the influence of lung volume and chest wall configuration on EMGdi center frequency (CF) while controlling for the ME distance filter and signal quality. Five subjects performed six static contractions of the diaphragm at each of seven chest wall configurations, as evaluated by the method of K. Konno and J. Mead (J. Appl. Physiol. 22: 407-422, 1967). EMGdi was measured with seven pairs of electrodes mounted on an esophageal catheter. The pair of electrodes whose EMGdi power spectra were the least filtered by the ME distance was assumed to be closest to the diaphragm. The results of the study indicated that 1) EMGdi power spectra were strongly affected by the distance between the diaphragm and the electrodes. CF decreased by approximately 1 Hz/mm displacement away from the electrode pair closest to the diaphragm; and 2) no systematic relationship was found between changes in chest wall configuration and CF, when CF was measured from the electrode pair closest to the diaphragm. We conclude that the EMGdi CF can be reliably measured with a multiple-array esophageal electrode that covers the span of diaphragmatic excursion and by selecting the pair of electrodes that is the closest to the diaphragm.

Diaphragm↗
PubMed1995

Clinical and chest radiographic features of tuberculosis associated with human immunodeficiency virus in Zimbabwe.

In the developing world, the diagnosis of tuberculosis is dependent on clinical and radiologic features as culture facilities are not readily available. It has been reported that tuberculosis in HIV-positive persons can present with atypical clinical and radiographic features. The object of this study was to examine how often atypical features occur in HIV-positive compared with HIV-negative persons and how these findings correspond to sputum-smear findings. Detailed demographic, clinical, and chest radiographic features of tuberculosis were assessed in 202 HIV-positive adults and 220 HIV-negative patients admitted consecutively. Using univariate analysis, several of these features were found to be significantly associated with being HIV-positive, but after multiple regression analysis only, age group (15 to 42 yr), a negative tuberculin response, intrathoracic lymphadenopathy, and lack of cavitation but not sputum-smear status remained significant.

AIDS-Related Opportunistic Infections↗