Effects of ascorbic and dehydroascorbic acid on the multiplication of tumor ascites cells in vitro

Summary The effects of AA and DHA on ATP C⁺ cell multiplication in vitro were studied by measuring incorporation of ³H thymidine into DNA. The results obtained demonstrate that both AA and DHA have the same effects: they favor cell multiplication at low doses and inhibit it at high doses. Experiments carried out with serial doses of both these substances revealed that AA is more efficient in determining both stimulating and inhibiting effects. The lesser efficiency of DHA may be attributed to its limited stability in culture medium. Studies on the effect of high doses of AA and DHA added to the culture medium in single or fractionated doses revealed that fractionated administration is more efficient in inhibiting cell multiplication than single administration.Abbreviations AA ascorbic acid - DHA dehydroascorbic acid - ATP C⁺ ascites tumor Perugia in Balb C⁺ mice - GSH reduced glutathione     

Serum Ornithine Carbamoyl Transferase as a Surrogate Marker in Malaria

Ornithine carbamoyl transferase (OCT) activity and other liver function tests were studied in a total of 50 patients of clinical malaria and 15 controls. They were grouped as group I (positive for malarial parasite on peripheral blood smear, n=18), group II (negative for malarial parasite on peripheral blood smear (PBS) but responded to antimalarials, n=17) and group III (peripheral blood smear negative and did not respond to antimalarial therapy, n=15). The mean OCT levels were significantly raised in group I (6.79 ± 1.84 IU/L, p value = 0.006) and group II (5.0 ± 1.15 IU/L, p value = 0.014) as compared to controls (2.5 ± 1.13 IU/L) and returned to normal after treatment In contrast, group III had normal levels except in a case of kala azar and septicemia where OCT levels were high and increased further on treatment. Taking PBS positivity as a gold standard of diagnostic criteria, OCT had a sensitivity of 83% and specificity of 86% with a high positive predictive value of 88% as compared to ALT which had a lower sensitivity of 55% and specificity of 80%. The clinical response rate in PBS negative cases of fever having high OCT level was 83% as compared to 35% in cases with normal OCT level, making OCT a good surrogate marker of malaria. OCT levels could also be of prognostic significance as 2 cases of cerebral malaria had high OCT levels of 11.1 UAL and 10.7 IU/L, respectively.Key Words: Malaria, Ornithine carbamoyl transferase     

Differing expression of enzymes of the glyoxalase system in superficial and invasive bladder carcinomas

This work aimed to study the activities of the glyoxalase system enzymes (glyoxalase I (GI) and glyoxalase II (GII) and their gene expression in human bladder carcinomas compared with the corresponding normal mucosa. Samples of these tissues were collected from 26 patients with superficial (SBC) or invasive bladder cancer (IBC) and used to evaluate enzyme activity and gene expression by northern blot analysis. In keeping with the electrophoretic pattern and the expression level of the respective genes, GI activity significantly increased in SBC samples, while it remained unchanged in IBC samples compared with the normal mucosa. In contrast, GII showed a higher activity in the tumour (either SBC or IBC samples) versus normal tissues. These results confirm the role of the glyoxalases in detoxifying cytotoxic methylglyoxal (MG) in bladder cancer. The differing levels of GI activity level and gene expression of GI between the SBC and IBC samples could help in their differential diagnosis.     

Acetylcholinesterase in Alzheimer's disease

Since the discovery of the cholinergic deficit in Alzheimer disease (AD), acetylcholinesterase (AChE) has been widely investigated in tissues involved in the disease. These studies showed modifications in AChE activity and changes in its polymorphism in brain as well as in cerebro-spinal fluid (CSF) and blood. The co-localization of the enzyme in the senile plaque provided evidence of its anomalous features. It has been also shown that AChE forms a stable complex with senile plaque components through its peripheral anionic site. Moreover, the neurotoxicity of amyloid components is increased by the presence of AChE. The occurrence of an altered glycosylation of some AChE forms in AD is closely related to the presence of amyloid formations. Literature on expression, relationships and modifications in the molecular polymorphism of AChE, in brain, CSF and blood in AD is reviewed.     

Spectrin-alpha I/61: a new structural variant of alpha-spectrin in a double-heterozygous form of hereditary pyropoikilocytosis

Recent biochemical studies have led to the identification of abnormal spectrins in the erythrocytes of patients with hereditary pyropoikilocytosis (HPP) and hereditary elliptocytosis (HE). In this report we describe the biochemical characterization of the erythrocytes from a proband with severe HPP who is doubly heterozygous for two mutant spectrins (Sp): Sp alpha I/74 and a new, previously undetected, mutant of alpha-spectrin designated Sp alpha I/61. The proband's erythrocytes are unstable when exposed to 45 degrees C, and her membrane skeletons exhibit instability to shear stress. The content of spectrin in the proband's erythrocyte membranes is decreased to 75% of control values. The amount of spectrin dimers in crude 4 degrees C spectrin extracts is increased (58%) as compared with control values (6% +/- 4%). Limited tryptic digestion reveals a marked decrease in the normal 80,000-dalton alpha I domain, an increase in the 74,000-dalton fragment that is characteristic of Sp alpha I/74, and an increase in a series of new fragments of 61,000, 55,000, 21,000, and 16,000 daltons. Both parents are asymptomatic, but they have increased amounts of spectrin dimers (17% to 25%). Limited tryptic digestion of the father's spectrin demonstrates the presence of a previously identified abnormal spectrin (Sp alpha I/74) that is characterized by a decrease in content of the 80,000-dalton peptide and an increase in concentration of the 74,000-dalton peptide. The mother's spectrin digests show a decrease in the amount of 80,000-dalton peptide and the formation of new peptides of 61,000, 55,000, 21,000, and 16,000 daltons. The data indicate that this severe form of HPP is due to the inheritance of two distinct abnormal spectrins, Sp alpha I/74 and a new spectrin mutant, Sp alpha I/61.