Evaluation of a flow cytometry-based assay for natural killer cell activity in clinical settings

Natural killer (NK) cells are not only important in first line defence against viral and bacterial infections, but also in immune surveillance of malignant cells and thus NK cell cytotoxicity is primary indicator of immune function. Although chromium release assay is recognized as 'gold standard' for measuring NK cell activity, it has disadvantages like use of radioactive compounds, poor loading and high spontaneous release. It is difficult to perform this assay in clinical laboratory because of difficulties with disposal of radioactive waste and standardization problems. We describe a flow cytometry-based assay for the measurement of NK cell activity by incorporating fluorescent dye, DiO, into membranes of target cells. NK cell activity was measured at baseline, 1 and 4 weeks follow-up in 20 normal healthy individuals on a dietary supplement immunomodulator to enhance NK cell function. Mean baseline NK cell activity percentage (21.5; SD = 9.3) increased significantly to a maximum level at 1 week (31.3%; SD = 7.9; P = 0.007) and then returned to baseline level at 4 weeks (21.5; SD = 8.3). An important feature of flow cytometry-based assays is its ability to discriminate effector cells from target cells, and potential for explaining molecular interactions underlying target cell lysis. Under clinical settings, this assay will be of interest for frequently monitoring immunological status of patients on treatment for various diseases that affect their immune status. The assay is easy to perform without using radioactive material and thus could become a tool for monitoring pathogenesis and immune reconstitution.     

Prevalence of hypertension among the elderly Malays living in rural Malaysia

Background

We are living in an ageing world. The prevalence of hypertension which is an established risk factor for cardiovascular disease and stroke increases with age. The aim of the study was to determine the prevalence of hypertension among the elderly Malays living in rural parts of north Malaysia.

Method

This cross-sectional study was conducted among the elderly (aged ≥60) Malay residents living in 22 villages in a northwestern state called Kedah in Malaysia from 2007 to 2009. Kedah has one of the highest rates of elderly population in the country. Data was collected by trained research assistants. Besides the baseline demographic information, blood pressure was measured using standardised methods using a manual sphygmomanometer.

Results

The response rate was 97.7%. The prevalence of hypertension among the elderly in these villages was 54.5% (228), 118 (28.2%) were known to be hypertensive and were on medication and an additional 110 (26.3%) respondents were newly diagnosed. Elevated mean systolic (146.17 ± 25.23) and diastolic (89.68 ± 15.60) blood pressure was noted among the known hypertensive. There was an almost fourfold risk (OR 3.64) of having uncontrolled blood pressure among the known hypertensive on treatment. Those with malnutrition were at an almost twofold at risk of being hypertensive (OR 1.73). Binary logistics regression showed occupation (OR 1.65), marital status (OR 2.32) and body mass index (BMI) (OR 1.62) as significant predictor variables.

Conclusion

Screening the elderly for hypertension will benefit this group of people by reducing the morbidity and mortality associated with this condition     

Correlation of CD4+ T cell count with total lymphocyte count, haemoglobin and erythrocyte sedimentation rate levels in human immunodeficiency virus type-1 disease

Background: Studies in human immunodeficiency virus (HIV) infected adults have demonstrated association of total lymphocyte count (TLC) <1200/mm³ and subseqnent disease progression or mortality. The association of other surrogate makers such as haemoglobin (Hb), and erythrocyte sedimentation rate (ESR) with CD4 count and disease progression has also been suggested. This study was carried out to determine the relationship of CD4-positive T lymphocyte counts with TLC, Hb and ESR in HIV-infected individuals.Methods: The study population comprised of 215 antiretroviral treatment naive HIV-1 infected adults. The CD4 positive T cell counts, TLC, Hb and ESR of study participants were measured. Spearman's rank order correlation and Receiver Operating Characteristic were used for statistical analyses.Result: The sensitivity, specificity, positive and negative likelihood ratios for cut-off value of TLC <1200/mm³ for predicting CD4 counts <200 cells/mm³ and <350 cells/mm³ were 9.4%, 100%, not measurable and 1.1, and 6.1 %, 98.8 %, 5.13 and 0.95, respectively. The association of Hb (<10, 11, 12 g/dl and <10, 12, 14 g/dl for CD4 counts <200 cells/mm³ and <350 cells/mm³, respectively), and ESR (<10, 20 and 30 mm fall after 1 hour) with these two CD4 counts cut-off values were suboptimal.Conclusion: This study reveals the poor association of TLC, Hb, and ESR with CD4 counts in HIV infected adults, thus highlighting the need to review the utility of these surrogate markers, for predicting CD4 counts in people living with HIV/AIDS.     

A novel link between Tourette's syndrome and histaminergic signalling

l ‐Histidine decarboxylase and Tourette's syndrome Ercan‐Sencicek et al. (2010) The New England Journal of Medicine 362(20): 1901–1908     

Insulin effects on CSF norepinephrine and cognition in Alzheimer's disease

We assessed the effects of induced hyperinsulinemia on plasma and cerebrospinal fluid (CSF) levels of norepinephrine (NE) and on cognition for patients with Alzheimer's disease (AD) and normal older adults. For normal adults, insulin increased plasma and CSF NE levels; also, recall for paraphrased details of a story improved as CSF NE levels increased. Mental control was positively correlated with CSF levels of NE for patients. These findings demonstrate that raising peripheral insulin levels can modulate CNS NE levels and suggest that insulin-stimulated increases in NE may modulate cognitive functions.