Effect of chloroquine on serum vitamin B12 and its binding proteins in patients with plasmodium vivax.

Chloroquine (CQ) is widely used as an antimalarial agent. It is accumulated in the lysosomes of various types of cells and inhibits the intralysosomal degradation of a wide range of proteins. CQ is found to interfere with vitamin B12 transportation in vitro and in the experimental animal. The present study was performed in order to determine such interference in humans receiving CQ. Serum vitamin B12 and vitamin B12 binding proteins were determined in 13 patients with P.vivax, both before and after receiving six tablets and 10 tablets of CQ. There were no significant differences between serum vitamin B12, UBBC, TBBC and TC values in patients before and after taking 6 tablets of CQ. A slight but not significant decrease in serum vitamin B12 and a significant increase in serum TCII were found after taking 10 tablets of CQ. The low serum vitamin B12 could be due to the effect of CQ on prevention of lysosomal degradation of intrinsic factor, leading to the accumulation of IF-B12 in the intestinal mucosa. As CQ also inhibits the intracellular degradation of TCII, therefore, more TCII levels are synthesized and secreted from various organs by the feedback mechanism. All these findings indicated the CQ had some effects on vitamin B12 absorption and transportation. However, these effects were relatively unsevere for the required dose of CQ in the treatment of P.vivax malaria.

Increased circulating levels of transcobalamin II in typhoid fever.

Many previous studies have shown that serum transcobalamin II (TCII) is usually elevated in patients with a stimulated and proliferative reticuloendothelial system resulting from such diseases as multiple myeloma, systemic lupus erythrematosus, dermatomyositis, rheumatoid arthritis and Gaucher’s disease. As reactive macrophage hyperplasia with monocytosis also occurs in patients with typhoid fever, we therefore studied TCII in these patients. The mean value of serum TCII was significantly higher in the typhoid patients’ group, and 15 out of 35 patients had serum TCII values over 2,000 pg/ml. There was no relationship between serum TCII and white blood count, haemoglobin or haematocrit values. The increased serum TCII level in typhoid patients was possibly due to increased synthesis by the proliferative mononuclear cells derived from reticuloendothelial tissue in various organs such as the spleen, liver and mesenteric lymph nodes. This supposition is supported by a previous report that TCII is synthesized in part by mouse peritoneal macrophages, as well as by human monocytes and macrophages which produced and secreted considerable amounts of TCII into the medium. Findings of increased serum TCII in typhoid patients therefore add a new area of information which has never been studied before.

Serum cholinesterase and erythrocyte acetylcholinesterase activity in patients with neuroblastoma.

Serum cholinesterase (ChE), red cell acetylcholinesterase (AChE), were determined in 18 neuroblastoma patients ages ranged from 8 months to 4 years. Sixteen patients (89%) were anemic and 15 patients (83%) showed bone marrow invasion and/or liver involvement. Both mean values of serum ChE and red cell AChE activities were significantly lower than those of 80 normal subjects. There was no relationship between red cell AChE and Hb, Ht or white blood cell count. The cause and mechanism of reduced serum ChE and red cell AChE activities in patients with neuroblastoma were possibly due to the invasion of the liver and bone marrow by the tumor cells. Although neuroblastoma cells can synthesize AChE which is inversely regulated by the rate of cell division, determination of serum ChE and red cell AChE could not serve to distinguish neuroblastoma from the other types of human tumour cells.

A case with multiple myeloma, polycythemia vera and acute myelomonocytic leukemia.

An 83-year-old man with evidence of multiple myelome was admitted to the hospital with a history of weakness. His serum protein immunoelectrophoresis demonstrated monoclonal IgA lambda and bone marrow aspiration revealed plasma cells 20%. Two months alter, hematological examinations showed erythrocytosis, luecocytosis and thrombocytosis. The bone marrow showed hypercellular with increased plasma cells and monoblasts. Serum vitamin B12 and vitamin B12 binding proteins confirmed the diagnosis of polycythemia vera. After treatment with Busulfan, Prednisolone and Endoxan for 6 months, his blood examination revealed increased monocytes, metamyelocytes and myelocytes. Bone marrow examination confirmed the diagnosis of acute myelomonocytic leukemia with plasma cells. This patient is an example of the simultaneous occurrence of lympoproliferative and myeoproliferative disorder.

Acetylcholinesterase activity in the amniotic fluid of normal Thai pregnant women.

Acetylcholinesterase (AChE) activity was determined for 112 amniotic fluid samples obtained by amniocentesis from normal Thai pregnant women at gestational ages of 34 to 40 weeks. The method for estimation was based on inhibition the of non-specific cholinesterase (ChE) with ethoprorpazine and the expression of residual AChE activity as a percentage of total cholinesterase activity. The mean values of AChE and total ChE activities were found to be 3.65ฑ1.97 U/1 (range 1.10-7.72 U/1) and 7.61ฑ 2.55 U/1 (range 3.31-14.34 U/1) respectively. These values were in the same order of magnitude as results reported earlier in normal pregnant women. There were no relationships between gestational ages and amniotic fluid AChE, ChE or total ChE activities. As the concentration of AChE in the amniotic fluid is the index of the secreted AChE from neurons, it therefore increases considerably in fetus with open neural tube defect (NTD). The results for this pregnant women study is a base-line data for normal Thai pregnant women which will be useful in detecting the NTD in the fetus.

Acetylcholinesterase activity in cord serum and human milk.

Acetycholinesterase (AChE) and pseudocholinesterase (ChE) were determined on 44 cord serum and 72 human milk samples. The mean values of AChE were found to be 87 U/1 (rang 66-176 U/1 (range 1.1-6.6 U/1) in the cord serum and human milk respectively. There were no significant difference between the mean values of AChE in the milk samples collected on day 3 to day 12 after delivery. There was a tendency for increased AChE in the milk in the multi-gravidas more than in the first gravida. As the function of AChE in the milk is not exactly known at the neonatal gut because such systems required for the degradation of various amino acids are still not fully developed in the newborn. As AChE could not be detected in the neonatal serum aged 5 days, this indicatied that the enzyme in the milk. Cord serum contained a significantly lower ChE level than that of adult serum. As this low level rose in the first day and reached a double value within 3 weeks after delivery, this could not be due to the intake of the relatively low ChE in the human milk.

Cholinesterase activity in serum and red cells of patients with retinoblastoma.

Serum cholinesterase (ChE) and erythrocyte acetylcholineaterase (AChE) activities were determined in 25 patients with retinoblastoma as well as in 80 normal subjects. There was no significant difference between the mean values of serum ChE in the group of patients and the normal group. These patients had a significantly lower mean value of red cell AChE activity than that of the normal subjects (P<0.01). Eleven out of 25 (44%) patients had red cell AChE activity lower than the normal limits. There was no relationship between erythrocyte AChE activities and Hb, Ht, red cell and white cell counts. Only 2 (8%) and 5 (20%) patients showed bone marrow and liver involvement, respectively, while 9 (36%) patients were anaemic. The cause and mechanism of reduced erythrocyte AChE activity in patients with retinoblastoma was not exactly known. One possibility was that the chromosome defect which predisposed to retinoblastoma may be the cause of intrinsic cellular defect of AChE synthesis.