Serum transcobalamin II levels in patients with acute and chronic renal failure.

Serum TCII levels were determined in 57 patients with acute and chronic renal failure. They were divided into 3 groups, group I was malarial patients with acute renal failure, group II and III were patients with acute renal failure and chronic renal failure from other underlying causes, respectively. All patients in group I had serum TCII over 2000 pg/ml while these values were within the normal limits in the other 2 groups. These findings indicated that elevated serum TCII occurred only in malarial patients with acute renal failure. The clearance and urinary excretion of TCII in malarial patients were found to be lower and increased to the normal levels after recovery from azotemia, indicating that the failure of excretion of TCII by the kidneys may be responsible for elevated serum TCII levels. The pathophysiological changes in the kidneys in malarial patients may reduce the amount of filtered TCII-B12 through the glomeruli and decrease TCII-B12 uptake by the renal tubules resulting in the decreased TCII degradation by tubular cells. Therefore, the intravascular TCII survival is prolonged with elevated serum TCII levels in these patients.

Serum transcobalamin II levels in patients with malaria infection.

Serum transcobalamin II (TCII) levels were determined in 56 patients with P. falciparum malaria infection. They were divided into 3 groups: severe (malarial parasite > 5% or patients with cerebral malaria or renal insufficiency), moderate (1-5% infection without complications) and mild (1% infection). Elevated serum TCII values were found only in patients with severe malaria infection. These values correlated directly with parasitemia, blood urea nitrogen and creatinine, but were not correlated with alkaline phosphatase. As 17 patients with azotemia had elevated serum TCII levels while other 3 patients with normal BUN and creatinine concentrations had serum TCII levels within the normal limits. These findings indicated that malarial patients with renal insufficiency had increased serum TCII. A possible mechanism is the reduced TCII-B12 that filtered through the glomeruli due to the reduced renal blood flow with the decreased its uptake by proximal tubular cells resulting in the decreased degradation of TCII by the tubular lysosomal enzymes. Determination of serum TCII level may be used as an indicator of renal function in malarial patients with renal insufficiency.

Persistently elevated serum transcobalamin II in a patient with cerebral malaria and typhus infections.

A 25-year-old man presented with a history of fever, chills and vomiting for three days. The parasite count was 207 ring-forms of P. falciparum per 1000 red cells. He developed hemoglobinuria and excreted hemoglobin in the urine 0.20-0.30 g/dl for 14 days during admission. Many blood transfusions were administered for correcting anemia. Although the malarial parasites disappeared one week after anti-malarial therapy, however, the fever and hemoglobinuria persisted. The Weil-Felix reaction OXK was positive with a titre of 1:40 on admission and increased to 1:160 on the second week. Chloramphenical and prednisolone were given for treatment of typhus fever and all symptoms subsided. Serum TCII levels were found to be increased and persisted high during the hemoglobinuria. The clearance of TCII was lower and increased relatively slowly to the normal level on day 30. On the other hand, TCII excretion in the urine was found to be increased during hemoglobinuria. These findings indicate that the catabolism and clearance of TCII in this patients is impaired with increased TCII excretion in the urine in parallel to the hemoglobinuria. Serum TCII level is, therefore, increased and persistently high in a patient with malaria and typhus fever infections with hemoglobinuria.

Abnormally elevated serum transcobalamin II levels in patients with cerebral malaria.

Transcobalamin II (TCII) levels have been reported to be elevated in patients with many clinical conditions including proliferative reticuloendothelial system. As reactive macrophage hyperplasia frequently occurs in patients with malaria, the objective of the present study was to determine TCII in patients with Plasmodium falciparum with cerebral symptoms. The studies were performed on 14 cerebral malaria patients as well as 60 normal subjects. The mean values of serum vitamin B12 and TCII levels were significantly higher in the patient group and 6 and 7 patients had serum vitamin B12 and TCII levels higher than the normal values. There was direct relationship between serum TCII levels and BUN or creatinine levels. These findings indicated that raised serum TCII level occurred only in patients with renal insufficiency. A decreased glomerular fiLtration rate reduced the amount of vitamin B12 and TCII-B12 that filtered through the glomeruli resulting in the reduced proximal tubular cells uptake and its degradation of TCII. This reduced lysosomal enzyme activity, therefore, prolongs the intravascular TCII survival and increased secretion of TCII into the circulation. Therefore, serum TCII levels were elevated in these cerebral malaria patients.

Optic neuropathy in a patient with vitamin B12 deficiency: a case report.

A 19-year-old man presented with blurring of vision for 2 weeks. He also complained of anorexia with weight loss during the past 4 months. Eight years ago, his small bowel from midportion of the jejunum, ileum, ascending colon and transverse colon were resected because of gangrene. He gave no history of exposure to tobacco, alcohol or other toxins. The bone marrow aspiration showed hypocellular with panhypoplasia. Serum vitamin B12 level was low while serum and red cell folate were within normal limits. His visual acuity was 5/200 in both eyes with centrocecal scotomas in both eyes. Other neurologic and ophthalmic examinations were found to be normal. The patient was given intramuscular injections of 1,000 micrograms of cyanocobalamin. Four months later, his visual acuity improved, serum vitamin B12 level and the bone marrow returned to be normal. This is a frank case of optic neuropathy in a patient with vitamin B12 deficiency due to a massive small bowel resection.

Superoxide dismutase and catalase activities of cultured erythrocytes infected with Plasmodium falciparum.

It has already shown that catalase activity is significantly decreased in red cells of patients with P. falciparum. The mechanism suggested was by this enzyme inactivation through increased H2O2 generated during malarial infection. The present study was performed to verify this hypothesis. Catalase activities of red cells with high or low parasitemia in patients with P. falciparum were found to be lower than those of normal red cells. However, P. falciparum-infected red cells cultured for one week showed similar SOD and catalase levels to normal red cells. There was also no significant difference in the catalase levels between the parasitized and non-parasitized red cells. The difference in catalase activity of infected red cells before and after culture could be explained in terms of the activation of mononuclear cells and macrophages in vivo. During the sojourn of the parasitized red cells in close proximity to the macrophages of the spleen, they might trigger oxidative bursts resulting in increased H2O2. In order to protect themselves from oxidant damage, the catalase in the infected red cells could be inactivated by H2O2 resulting in the reduction of this enzyme.

Folic acid, vitamin B12 and vitamin B12 binding proteins in patients with neuroblastoma.

Serum vitamin B12, serum and red cell folate and serum vitamin B12 binding proteins were determined in 18 patients with neuroblastoma, with ages ranging from 8 months to 14 years. A mean value of serum vitamin B12 level was slightly but not significantly lower than that of the normal subjects but all of them had serum vitamin B12 levels over 150 pg/ml. There was no relationship between serum vitamin B12 levels and hemoglobin, hematocrit or white cells. Transcobalamin I (TCI) was significantly increased resulting in slightly elevated UBBC and normal TBBC levels in these patients. This could be a compensatory mechanism for the low serum vitamin B12 by increasing the unsaturated vitamin B12 binding capacity of TCI. All these findings indicated that the status of vitamin B12 in patients with neuroblastoma was within the normal limits. Treatment of neuroblastoma by giving a high dose of vitamin B12 would therefore not give any direct therapeutic effect. Both serum and red cell folate concentrations were significantly lower in the group of patients. As only 2 out of 18 patients had low serum folate and none of them had red cell folate lower than the lower limit of normal subjects; therefore these patients were only in the state of negative folate balance.

Acetylcholinesterase activities in cerebrospinal fluid of patients with Plasmodium falciparum cerebral malaria.

Serum cholinesterase (CHE) and acetylcholinesterase (ACHE) in cerebrospinal fluid (CSF) were determined simultaneously in 30 patients with P. falciparum cerebral malaria. Nineteen patients (63%) had low serum CHE and mean value of this serum enzyme in 30 patients was significantly lower than that of non-infected group. CSF ACHE levels were found to be significantly lower than those of normal subjects reported earlier. Post-treatment in the hospital for one week, both serum CHE and CSF ACHE levels in 9 convalescent subjects increased significantly. These findings indicated that both serum CHE and CSF ACHE levels were depressed in patients with cerebral malaria and increased on recovery.

Red cell acetylcholinesterase activity in Plasmodium falciparum malaria.

Red cell ACHE activity was determined in 19 patients with P. falciparum malaria, 13 patients during convalescence as well as in 6 normal subjects. There was no significant difference between the mean values of ACHE in red cells of these 3 groups. After separation these blood samples into 2 portions by centrifugation in 5% Ficoll solution, the parasitized red cells in the lower portion which are mostly ring forms contained the same amount of ACHE activity as those of the normal subjects and the non-parasitized red cells. However, the parasitized red cells in the upper portion which contained predominantly mature asexual forms revealed a significantly higher ACHE activity than those of the normal red cells. There was also a reverse relationship between red cell ACHE activity and the parasitaemia from this portion of blood sample. These findings indicated that although malarial parasite invaded and caused the red cell membrane damage, it did not inactivate ACHE. It may be concluded that ACHE was not responsible for the anaemia and excessive erythrocyte destruction in patients with P. falciparum malaria.

Serum cholinesterase activity in patients with malaria infection.

Serum cholinesterase activities were determined in 87 patients of both sexes with P. falciparum malaria in comparison to those of 80 blood donors. Patients with acute P. falciparum malaria had significantly lower serum cholinesterase activity than those of the control group. After treatment, their serum cholinesterase levels returned to the normal level. Serum albumin concentration also showed the same pattern and had a direct relationship to those of serum cholinesterase levels. These findings indicated that malarial parasites had some effect on the liver cells which resulted in impaired hepatic synthesis of serum cholinesterase and albumin concentrations. This result therefore add new information that there was a disturbance of enzyme cholinesterase among many liver enzymes that have been shown to be altered during an acute malarial attack.