Hematologic parameters in Thai subjects over 50 years old.

Advancing age is associated with the decline of hemoglobin, red blood cell count and other parameters. The conventional normal values of hematologic parameters established by all age populations may not be suitable for the elderly. This study determined the hematologic parameters of Thai subjects aged over 50 years by using a fully automated cell counter. No significant age-related variations of all parameters were found. The MCV of both sexes showed an upward trend at age over 70. The red blood cell count and hemoglobin levels in males were higher than females. These, however; were not significant alterations. These hematologic values should be useful for screening and clinical investigation of the elderly.

Standardization of platelet aggregation test in normal Thai adults.

Platelet aggregation test was assessed by the turbidimetric method in 52 normal Thai adults consisting of 24 males and 28 females with ages ranging from 20 to 50 years. The aggregating agents used were adenosine diphosphate (ADP), adrenaline and collagen. It was found that the ranges of threshold concentration of ADP, adrenaline and collagen which gave maximal induction of platelet aggregation were 5-10 microM, 2.5-10 microM and 0.14-0.28 mg/mL, respectively. Collagen at the above concentration, showed lag phase within 2 minutes. This corresponds to that described in the reference method. Moreover, when induced by ADP and adrenaline 53-65 per cent and 81-87 per cent of the subjects, respectively, showed biphasic curve. The above concentration of ADP, adrenaline and collagen are suitable for the study of platelet aggregation in normal Thai adults.

Cytochemical reactions of homozygous beta-thalassemic spleens.

Splenic cells from 10 homozygous beta-thalassemic patients were stained using cytochemical reactions: non specific esterase and acid phosphatase. Spleens from nonthalassemic subjects: a normal case who underwent gastric surgery and 5 idiopathic thrombocytopenic purpura, were also studied to serve as the control. In thalassemic spleens, no positive dot cell was shown in periarteriolar lymphocyte sheaths (PALS) when they were stained with both nonspecific esterase and acid phosphatase. In contrast, dot positive reaction was demonstrated in 92 per cent of cells from a normal spleen. These cells were presumably T lymphocytes. There were two possibilities to explain our study 1) the absence of T lymphocytes in the PALS of white pulps in homozygous thalassemia may have an impact on the immune system related to infection complication in thalassemia 2) T lymphocytes in the thalassemic spleen may be present but they do not give a positive ANAE dot reaction.

Blood cell production and hemostatic mechanism in Thai vegetarians.

The activity of hemostatic mechanism and blood cell production of 50 Thai vegetarians and 30 nonvegetarians were compared. The hemostatic mechanism of both vegetarians and nonvegetarians showed no significant difference, whereas, a significant decrease in hemoglobin, hematocrit and red blood cell count with significant increase in hypersegmented neutrophils were found in vegetarians who had taken vegetarian diets for over 4 years.