Determination of lymphocyte subset reference ranges in peripheral blood of healthy adults by a dual-platform flow cytometry method.

Flow cytometry has emerged as a useful screening approach to evaluate whether specific cell populations are present or absent. Previous studies have shown different reference ranges in several countries. The aim of this study was to determine reference ranges of lymphocyte subsets in peripheral blood by flow cytometric method in Brazilian adults. In this study, relative and absolute reference ranges of lymphocyte subsets were: CD3+: 51.3-83.5%, 718-2494cells/µl; CD4+: 24.4-54.2%, 456-1492cells/µl; CD8+: 12.8-40.2%, 272-1144cells/µl; CD4+CD8+: double-positive 0.01-3.6%, 2-88cells/µl; TCR γδ: 1.0-15.9%, 19-345cells/µl; CD3+CD4-CD8-: 1.2-13.3%, 28-292cells/µl; TCR αß+: 44.3-77.0%, 855-2384cells/µl; CD4/CD8 ratio: 0.68-3.61; CD19+: 6.3-20.8%, 112-622cells/µl; mature NK cells: 3.1-27.4%, 70-745cells/µl; immature NK cells: 0.08-1.1%, 1-23cells/µl; total NK cells: 3.7-28.5%, 82-760cells/µl; and NKT cells: 0.9-21.4%, 18-488cells/µl. Comparison with other studies showed differences among some of them. This suggests that there are differences among lymphocyte subsets in the worldwide population and also it is important to determine reference ranges in different populations in order to better assess and monitor patients.

Comparison between two portable hemoglobinometers and a reference method to verify the reliability of screening in blood donors.

Portable hemoglobinometers are used to determine hemoglobin level, but there are conflicting reports regarding their accuracy. The aim of this study was to compare results from two portable hemoglobinometers (HemoCue® and Hemo-Control) with an automated hematology analyzer (Sysmex XE-2100D) to determine if the screening of blood donors is reliable. A total of 426 blood donors' samples were studied and on average the Hb content measured in capillary blood samples was higher than that found in venous blood samples. Hemoglobinometers can be employed as a method to screen blood donors, but critical values should be confirmed in an automated hematology analyzer.

Effects of flavonoids on α-glucosidase activity: potential targets for glucose homeostasis.

OBJECTIVE: Flavonoids are naturally occurring compounds widely distributed in plants, which have hypoglycemic potential and have been described as glucosidase inhibitors. This study evaluated the effect of flavonoids on intestinal glucosidase activity after in vivo and in vitro treatment. METHODS: For the in vivo studies animals received quercetin by gavage and for the in vitro assays a segment of the small intestine was used. To obtain the oral glucose tolerance curve fasted normal rats were loaded with glucose plus flavonoids. The glycemia was measured by the glucose oxidase method. RESULTS: Quercetin reduced the effect of sucrase and maltase in the in vivo and in vitro treatments. It was observed in the in vitro studies that the maximum inhibitory effect of kaempferitrin was around 23% for maltase activity. Also, for the sucrose substrate the specific enzyme activity was significantly decreased. Aglycone, flavonoids, and kaempferol decreased significantly the maltase activity at all concentrations assayed. Finally, rutin reduced maltase-specific activity at all concentrations studied. According to the oral glucose tolerance curve, rutin reduced the serum glucose levels at 15, 30, and 60 min when administered by oral gavage 30 min before glucose overload in rats. CONCLUSION: Based on these results, we can conclude that disaccharidases are targets of flavonoids in the regulation of glucose absorption and consequently glucose homeostasis.

Distribution of tryptophan hydroxylase-immunoreactive neurons in the brainstem and diencephalon of the pigeon (Columba livia).

The distribution of tryptophan hydroxylase (TPH)-containing perikarya and processes in the brainstem and diencephalon of the pigeon (Columba livia) were investigated using single-labeling chromogenic and double-labeling fluorescence immunohistochemical methods for TPH and 5-HT. TPH-immunoreactive (TPH-ir) perikarya were seen extending from the caudal medulla to mid-hypothalamic levels, located in brainstem regions previously described as containing 5-HT-ir somata. Brainstem TPH-ir cell clusters (the midline raphe, and the dorsolateral and ventrolateral serotonergic cell groups) and the circumventricular cerebrospinal fluid-contacting neurons in the taenia choroidea (in the caudal brainstem), recessus infundibuli and paraventricular organ (in the hypothalamus) were shown to co-express 5-HT immunoreactivity. However, heavily labeled TPH-ir cell clusters were observed in the nucleus premamillaris (PMM), in the stratum cellulare internum (SCI), in the nucleus paraventricularis magnocellularis (PVN) and in the medial border of the nucleus dorsomedialis anterior thalami (DMA). Double-labeling experiments indicated that none of these medial hypothalamic TPH-ir cells were immunoreactive to 5-HT. These cells correspond to dopamine- and melatonin-containing neurons previously found in the avian hypothalamus, and appear to be comparable to the mammalian TPH-ir hypothalamic A11-A13 catecholaminergic somata, suggesting that they may be a conserved attribute in the amniote medial hypothalamus.