Lead exposure and accumulation in healthy Thais: assessed by lead levels, EDTA mobilization and heme synthesis-related parameters.

Lead is one of the pollutants which is of public concern. The magnitude of lead contamination in Thai people is of interest. The objective of this study was to evaluate the lead status in normal healthy volunteers. Normal volunteers were included. The blood for lead level, Zinc protoporphyrin (ZPP), delta-aminolevulinic acid dehydratase (ALA-D) activity, and baseline urine for lead, delta-aminolevulinic acid (ALA) and coproporphyrinogen III (CP3) were collected. The EDTA mobilization test was done. 24 hour urine after administration of the drug was collected for lead analysis. Thirty volunteers were included in the study. All were men whose average age was 32.5 +/- 6.9 years. The mean lead level was 5.95 +/- 2.01 micrograms/dL and 5.83 +/- 2.32 micrograms/L in urine. The 24 hour urine lead contents before and after EDTA administration were significantly different (11.11 +/- 6.72 and 16.05 +/- 9.51 micrograms respectively). Blood ALA-D activity was 251.6 +/- 80.4 unit/ml of RBC. Urine ALA and CP3 were 0.56 +/- 1.2 mg/L and 22.17 +/- 23.9 micrograms/L respectively. All were in the normal ranges. All parameters suggested that the healthy Thai volunteers had an acceptable magnitude of lead exposure and accumulation.

Development of a new method for detection of platelet factor 3 like activity.

We asked the question, "Can thalassemic erythrocytes play some role in alteration of the hemostatic system?", because clinical examination of thalassemic patients shows symptoms and signs related to alterations in hemostatic and circulatory systems, and thalassemic erythrocytes are different from normal erythrocytes. We obtained one of the answers to the question: The erythrocytes of postsplenectomized patients of beta-thalassemia/HbE disease could stimulate their own platelets to aggregate spontaneously. To know the role of erythrocytes in platelet aggregation, we wanted to examine the effect of thalassemic erythrocytes on the coagulation system by focusing of PF3-like activity of erythrocytes, because PF3-like activity of the ghosts of erythrocytes had been reported. For the study, we tried to develop a technique that was accurate and sensitive enough to detect PF3-like activity of blood. The system we developed was the following: 1) We activated the intrinsic coagulation pathway of commercial standard plasma by ellagic acid. 2) CaCl2, a fixed amount of PF 3 and synthetic thrombin inhibitor MD 805 were added to the reaction mixture. 3) At a fixed time, thrombin activity in the mixture was measured by using S-2238 as a substrate. At full activation of the contact system by ellagic acid, the amount of thrombin formed in a certain time depended on the amount of PF3-like substances such as cephalin, freeze-thawed platelets or ghosts of erythrocytes added to the test system, indicating that PF3-like activity of those substances can be measured by the activity of thrombin generated in a fixed time.(ABSTRACT TRUNCATED AT 250 WORDS)

Studies on the glomerular filtration rate and extracellular fluid volume in rhesus monkeys infected with Plasmodium knowlesi.

The glomerular filtration rate (GFR) and the extracellular fluid volume (ECV) were determined in 5 rhesus monkeys infected with P. knowlesi in comparison with 6 control monkeys by using 51Cr-EDTA. As the disappearance curve of the radioactivity showed a close fit to a double exponential equation, the data was therefore analysed by an open 2-compartment system. Results in the present study showed that the GFR was significantly reduced in the infected group. Both V1 and V2 were also slightly but not significantly decreased which resulted in the lower ECV in monkeys infected with P. knowlesi. As the GFR was reduced much more than ECV, therefore the mean transit time of 51Cr-EDTA in the infected group was longer than that of the normal group. All other intercompartment clearance and fractional transfer rate constants were also found to be lower in the infected group. These findings indicated that there was a delay in the distribution of 51Cr-EDTA between these 2 compartments in monkeys infected with P. knowlesi malaria.