Aberrations in cerebral vascular functions due to Plasmodium yoelii nigeriensis infection in mice

Plasmodium yoelii nigeriensis infection in mice caused an increase in uptake of 125I-labeled bovine serum albumin, 51Cr-labeled erythrocytes and Evans blue dye from peripheral circulation into the brain. Isolated cerebral microvessels which were characterized in terms of their morphology under scanning electron microscope and enhancement of the specific activities of biochemical markers, viz. alkaline phosphatase, gamma-glutamyl transpeptidase, and monoamine oxidase, showed significant decrease in these activities due to P. yoelii nigeriensis infection. On the other hand, relatively minor (statistically insignificant) changes occurred in the first two enzyme specific activities in the cerebral cortex and monoamine oxidase registered an increase in this tissue due to infection. Histological examination of the cerebral tissue of infected animals by light and electron microscopy showed broken blood vessel walls and leakage of erythrocytes into extravascular space, some of which contained intraerythrocytic malarial parasite in a state of cell division.

Oxido-reductive functions of Entamoeba histolytica in relation to virulence

Entamoeba histolytica can reduce nitro-blue tetrazolium (NBT) in Hank's balanced salt solution to almost the same extent as in Eagle's minimal medium. Further, this reduction was stimulated only to a minor degree by glucose, pyruvate and DL-serine, substrates known to support respiratory activity (O2 uptake) in E. histolytica. However, both NADH and NADPH increased NBT reduction several-fold, the effect being greater with NADPH. A sizeable proportion of this endogenous dye-reducing capability (in Hank's solution) was associated with low-speed sediments obtainable from amoebic homogenates, which also shared the bulk of 125I labelling (when the homogenates were prepared after surface labelling with Na 125I). Conversion of the dye to formazan was strongly inhibited by -SH blocking agents, but was not influenced by rotenone and antimycin A. The activity was also inhibited by H2O2, but stimulated by catalase. Superoxide dismutase only slightly curtailed NBT reduction in intact cells, but inhibited it in homogenates in a concentration-dependent manner to a maximal extent of 33%. Almost the same degree of curtailment of this activity was induced by anaerobic conditions. Both concanavalin A (Con A) and phorbol myristate acetate stimulated the activity in intact cells, though the effect of Con A was nullified by alpha-methyl mannoside. Both NBT-reducing capability and alcohol dehydrogenase activities were higher in the more virulent IP:106 strain, and they increased with time in cultures of NIH:200 in a cholesterol-enriched environment.

Partial purification of acid phosphomonoesterase in axenically grown Entamoeba histolytica NIH-200

Entamoeba histolytica possesses significant acid phosphatase activity as compared to alkaline phosphatase activity. The acid phosphatase activity in the amoebic cells eluted at higher saline concentration as three distinct peaks at 200, 300 and 400 mM sodium chloride.

Literacy differentials in tribal and non-tribal population of India, 1981

The author investigates literacy differentials between tribal and non-tribal populations in India, using 1981 census data. "Spatially, the index is high in tradition gripped and economically backward areas of Western Rajasthan, of central highlands and of Western Arunachal Pradesh. It is low in [the] Christian tribal belt of [the] northeast; the early exposed areas of [the] southern peninsula, parts of Gujarat, Maharashtra and Karnataka, and numerically insignificant areas of northern Rajasthan and Western Himalayas."

Biochemical and ultrastructural studies induced by phanquone on Entamoeba histolytica NIH-200

The action of phanquone on the incorporation of (14C)1-DL-valine and (14C)-8-adenine in TCA insoluble fractions of Entamoeba histolytica was examined as indices of RNA and protein synthesis respectively. The former was found to show greater sensitivity to the drug in terms of the effect manifested in the dose response curves for these parameters. Electron microscopic investigations with increasing concentrations of the drug demonstrated progressive vacuolization with concomitant dissolution of ribosomal helices. The drug had no significant effect on nucleus and plasma membrane even at concentration as high as 200 micrograms/ml.

p53 in colorectal cancer: clinicopathological correlation and prognostic significance

p53 protein was detected by immunohistochemistry in 42% of 52 colorectal adenocarcinomas. Positive tumours were significantly more frequent in the distal colon, and demonstrated a higher rate of cell proliferation. No correlation was found with tumour grade, Dukes' stage, presence of DNA aneuploidy or patient survival. The role of p53 in colorectal carcinogenesis is discussed with particular reference to differences between proximal and distal large bowel cancers.

Effect of Plasmodium yoelii infection on GABA metabolism of mouse brain

Plasmodium yoelii infection in albino mice decreased the activity of brain glutamic acid decarboxylase (GAD) by about 30 and 48% in crude homogenate and its synaptosomal fraction, respectively. The decrease was evident from 20% parasitemia and remained more or less constant up to 80% parasitemia. The Km values of GAD in normal and infected animals were 1.2 x 10(-2) and 3.3 x 10(-2) mM, respectively, indicating a decrease in enzyme substrate affinity due to infection. The lowered GAD activity rose to slightly above normal by treatment of infected animals with chloroquine. Decrease in GAD activity reflected lower gamma-aminobutyric acid (GABA) levels in the infected brain; however, GABA-transaminase activity was not significantly influenced by infection. It has been proposed that impaired GABA synthesis may be due to hypoxia induced by malarial infection.

Action of metronidazole on Entamoeba histolytica: an ultrastructural study

Metronidazole (19 micrograms/ml) caused progressive increase in vacuolization in Entamoeba histolytica cells with disintegration of its plasma membrane leading to almost complete disappearance of the latter within 3 hours. The drug also induced formation of helical ribosomal aggregates in the cytoplasm and disappearance of button like structures inside the nucleus.

Specific features of phosphomonoesterase of Entamoeba histolytica (NIH-200)

Axenically grown E. histolytica possess significant acid phosphatase activity. The Km of the enzyme was found to be 7.1 x 10(-3) and was maximally active at pH 4.5. Acid phosphatase activity was significantly inhibited by Cu2+, cysteine and was activated by tartrate and fluoride. It was found that E. histolytica acid phosphatase differs in some properties as compared to the enzyme reported from other sources.

Sensitivity of protein and RNA synthesis to antiamoebic drugs in axenic Entamoeba histolytica (NIH-200)

The action of antiamoebic drugs on the incorporation of (14C) 1-DL-valine and (14C)-8 adenine in TCA insoluble fraction of axenic Entamoeba histolytica was investigated. Adenine showed greater sensitivity to all the drugs tested viz. camoquin, chloroquine, diodoquin, metronidazole, entobex and diloxanide furoate except enterovioform.

Evidence for selection of virulent sub-populations of Entamoeba histolytica by cholesterol

Quantitatively much higher Concanavalin A (Con. A) agglutinability, haemolytic potency, and activities of acid hydrolases, namely phosphatase (EC 3.1.3.2), ribonuclease (EC 2.7.7.16), deoxyribonuclease (EC 3.1.4.5) and proteinase--were observed in a virulent strain of Entamoeba histolytica (IP-106), as compared to attenuated and avirulent strains (200-NIH) and DKB respectively. In addition, significant differences in these parameters were observed among clonal cultures derived from the latter two cultures by cultivation of single amoebic cells picked out by micromanipulation. Repeated sub-culturing of parent cultures of both these strains in cholesterol-enriched medium resulted in marked enhancement of all the above activities, but no such change occurred in the derived clonal cultures following similar cholesterol treatment. The implication of these findings in relation to enhancement of the virulence of E. histolytica by cholesterol is discussed.

Male-female literacy differential in India--1981

The author examines inequalities in the literacy rates between males and females in India. Regional variations in literacy are examined by district using maps. "The male-female literacy differential is low in coastal, peripheral and metropolitan areas and is high in inland and mountainous areas. These regional disparities are the product of differences in length of educational background, age at marriage, level of urbanisation, standard of living and proportion of socially conservative and backward sections of society.... The study in spatial dimension provides a strong base for the removal of sex biased discrimination in society."

Secretion of acid phosphatase by axenic Entamoeba histolytica NIH-200 and properties of the extracellular enzyme

Entamoeba histolytica (NIH-200) secreted large amounts of acid phosphatase in its external environment when grown axenically in modified TPS-II medium. Fractionation by DEAE-cellulose chromatography of the precipitate obtained from the cell-free medium at 60% ammonium sulfate saturation yielded 3 distinct peaks of enzyme activity. The enzyme in all the peaks showed resistance to tartrate but was inhibited by fluoride, cupric chloride, ethylene diamine-tetra acetic acid, ammonium molybdate and cysteine; however, enzyme associated with different peaks differed in its polyacrylamide gel electrophoretic profiles and behavior towards concanavalin A.

In vitro insulin action on erythrocyte glucose metabolism in normal and diabetic rats

Alloxan-induced diabetes in rats significantly impaired the capacity of the erythrocytes to metabolise glucose in vitro to either lactic acid or CO2. Both these metabolic activities were initially insensitive to insulin in normal as well as in diabetic animals; but became responsive when these cells were subjected to insulin and glucose 'starvation' for 1 h through incubation in their absence. This action of insulin in starved cells showed concentration dependence and required preincubation with the hormone prior to addition of glucose.

Sensitivity of protein and RNA synthesis to emetine in axenic Entamoeba histolytica

The action of emetine on the incorporation of (14C)1-DL-valine and (14C)-8-adenine in TCA insoluble fraction of axenic Entamoeba histolytica was investigated. These compounds were almost exclusively incorporated in the 'protein' and 'RNA' fractions, respectively. Incorporation of the purine showed a significantly higher sensitivity to emetine. While the percentage inhibition of valine incorporation by emetine decreased with increasing pH, the susceptibility of adenine incorporation was greater in the alkaline range.

Cholesterol induced changes in glucose-6-phosphate generating enzymes, concanavalin A agglutinability and haemolytic activity of axenic Entamoeba histolytica

Repeated passage of the 200-NIH strain of Entamoeba histolytica through cholesterol-enriched axenic growth medium induced marked increases in cholesterol, phosphoglucomutase and hexokinase levels and a less prominent rise in the protein content of amoebic cells. There was also pronounced enhancement of haemolytic activity and Concanavalin A (Con A) agglutinability of the culture, but no significant change was observed in glucose phosphate isomerase. These cholesterol-induced effects persisted to a large extent when amoebae were subsequently repassaged through normal axenic medium lacking exogenous cholesterol, but changes in cellular cholesterol and protein levels did not persist. Qualitatively similar results were obtained whether the sterol was layered as a film on the glass walls of the culture tubes or supplied as sonicated micells, but the latter was in general more effective.

Changes in insulin receptor functions of the erythrocyte by treatment of non-insulin-dependent diabetes mellitus (NIDDM) patients with glibenclamide and diet control

The insulin binding of erythrocytes from: (i) fifteen age-matched normal subjects, (ii) ten untreated NIDDM patients and (iii) fifteen treated (glibenclamide + hypocaloric diet) NIDDM patients (all males) has been studied. A significant decrease in specific insulin binding was observed in group (ii) which improved in cases controlled after treatment (group iii). Scatchard analysis of the results suggested that changes in insulin binding were due to alteration in the number of insulin receptors on erythrocytes. The number of insulin receptors/cell was 471 in normals, 160 in diabetics and 282 in treated diabetic subjects. No significant change in the binding affinity was observed in the three groups (1.0 X 10(8), 1.2 X 10(8) and 1.1 X 10(8) M-1 in normal subjects, untreated diabetics and treated diabetics, respectively).

In vitro insulin effect on acetylcholine esterase of erythrocyte membranes of normal and diabetic rats

Alloxan induced diabetes in rats was associated with a significant reduction in the acetylcholine esterase activity of the erythrocyte membrane. Preincubation of these membranes with insulin caused a rapid but transient stimulation of this enzyme activity in both normal and diabetic rats, the effect being more marked in the latter group.

Comparison of in vitro demyelination and cytotoxicity of humoral factors in multiple sclerosis and other neurological diseases

The distribution and nature of serum factors causing in vitro demyelination and glial lysis were investigated in multiple sclerosis (MS), other neurological diseases (OND), ill control and control groups. MS sera were unique in affecting only CNS myelin and glia whereas stroke and Guillain-Barré syndrome (GBS) sera brought changes to both CNS and PNS tissue. Through both visual scoring of myelin damage and the quantitative measurement of radiolabel release from cerebellar cultures, it was evident that the MS and OND groups have similar myelino- and cytotoxic effects. This may reflect MS and OND sera sharing similar humoral factors. 74% MS, 68% OND and 22% of control scores were above a score threshold designed to exclude culture handling trauma effects. When classified by their current disease state MS patients with severe and mild disease yielded higher in vitro scores than did those with moderate disease who comprised an older age group. No other clinical features of MS patients gave any association with in vitro serum effects. The rare demonstration of bound Fab IgG in cultures after MS serum tests indicates that immune mechanisms are unlikely to make a large contribution to serum-induced demyelination and cellular change in vitro.

In vitro insulin action on different ATPases of erythrocyte membranes in normal and diabetic rats

The in vitro effect of porcine insulin on Na+ + K+, Ca2+- and Mg2+-ATPases of the rat erythrocyte membrane of normal and alloxan-induced diabetic rats was investigated. Na+ + K+- and Ca2+-stimulated enzyme activities were significantly decreased in diabetic rats in comparison to normal animals. The specific activities of both these ATPases in the latter group were markedly reduced on pre-incubating the ghosts with insulin. Similar treatment of the erythrocyte membranes of diabetic animals, however, resulted in a significant increase of these activities. These qualitatively different effects of the hormone in the two groups increased progressively with hormone concentration and duration of pre-incubation. Mg2+-stimulated ATPase activity was not significantly affected in diabetes or by insulin.