Effect of silica aerosil dispersions on the dielectric properties of a nematic liquid crystal.

The static and dynamic aspects of (4-n-heptyl-4'-cyanobiphenyl) (7CB) perturbed by the dispersion of 70-A-diameter hydrophilic silica aerosil spheres have been investigated using dielectric spectroscopy. Results on five mixtures of 7CB plus silica aerosil are presented in order to probe systematically the disorder introduced by the silica aerosil network on the 7CB molecules. Measurements on homeotropically aligned samples have been made from 75 kHz to 30 MHz in the temperature range 30-60 degrees C. It was found for the mixtures that the nematic-isotropic transition temperature is lower than that of the bulk 7CB. Bulklike relaxation processes due to the rotation of the molecules around the short axis have been analyzed, and were found to follow Arrhenius-type behavior in the nematic phase except in the vicinity of the nematic-isotropic transition temperature. These processes are slightly faster in the mixture than in the free phase. A dielectric process in the low frequency range, absent in the bulk, has been observed in samples with higher silica concentration. All the observed relaxation processes in the mixtures are of non-Debye type.

Ultrasonic inspection of composite hydrogen reservoirs using frequency diversity techniques.

The use of the signal processing techniques based on the principle of quasi-frequency diversity can be a suitable solution for the ultrasonic inspection of liquid hydrogen tanks manufactured out of composite materials. Nevertheless, the algorithms developed up to now suffer from limitations that restrict their large-scale use. The split-spectrum processing requires preliminary adjustments that are not always accessible to the user, while the cut-spectrum processing is not sensitive enough to eliminate the noise. We have thus developed an interesting alternative to these two filters. Based on the use of progressive low-pass filters, this algorithm, called low-spectrum processing, takes into account the physical characteristics of the ultrasonic wave propagation in a composite material. Its use in the inspection of tanks made in composites showed better performances.

Torture in the eyes of a medicologist.

Usual torture victims examined by doctors do not have any physical evidence but careful history concerning the method of torture and their effect may provide important evidence. Psychological assessment is very important and will invariably reveal torture. The injury if present to be evaluated against the history and documented as common clinical documentation. Proper documentation is the best campaign of a doctor against torture.

Cardiovascular effects of yellow oleander ingestion.

Yellow oleander (Thevetia neriifolia) is a commonly grown tree found widely in Eastern India. The seeds of yellow oleander are highly poisonous and contain three glycosides--thevetin, thevetoxin and peruvoside. Yellow oleander seed ingestion is usually with suicidal intent in Eastern India. Manifestations range from mild to potentially fatal. It has significant cardiovascular effects with varying rhythm abnormalities. Effects of yellow oleander seed ingestion (YOI) were studied in 300 patients from 1986 to 1990 at BS Medical College, Bankura. Majority i.e., 246 (82%) were females and 226 (75.33%) were young in the age group 11-20 years. Most reported for treatment 6 to 8 hours after ingestion of seeds. The number of seeds swallowed varied from half to fifteen. Two hundred and ninety-two (97.33%) ingested seeds in the crushed form; 156 (52%) were asymptomatic, 92 (30.66%) had vomiting and 36 (12%) had palpitation. In electrocardiogram (ECG), 138 (46%) revealed varying types of arrhythmias including sinus bradycardia in 68 cases (49.27%). Ischaemic changes were present in 118 cases (39.33%). Number of seeds ingested did not bear any relationship with ECG changes in YOI. All 14 cases of death were autopsied. Subendocardial and perivascular haemorrhage with focal myocardial oedema was present in all. Median hospital stay was 5 days (range 2 to 24). During discharge, 256 (85.33%) had normal ECG, 14 (4.66%) had sinus bradycardia and 16 (5.33%) demonstrated ischaemic changes.

Plasma antioxidants and lipid peroxidation products in falciparum malaria.

To investigate the influence of Plasmodium falciparum malaria on plasma antioxidants and lipid peroxidation, plasma ascorbate, urate, total protein and albumin, ceruloplasmin and malondialdehyde (MDA) were determined in two groups of 42 patients each, one with mild and the other with severe falciparum malaria, and in an equal number of age- and sex-matched control subjects. Plasma MDA was found to be significantly higher in malaria patients, and the increase was proportional to the severity of the disease. Of the antioxidants, ascorbate and albumin decreased with severity of disease while urate and ceruloplasmin increased. Only ascorbate correlated inversely with MDA both in mild (r = -0.341, P < 0.05) and severe malaria (r = 0.545, P < 0.01). While plasma albumin correlated inversely (r = -0.442, P < 0.01), urate and ceruloplasmin correlated directly (r = 0.419, P < 0.01 and r = 0.349, P < 0.05, respectively) only in patients with severe malaria. These antioxidants also correlated well with markers of disease severity, indicating the influence of disease severity in regulating their levels in plasma. The presence of significant quantities of ascorbate and albumin, along with increases in some of the other antioxidants and MDA, indicates ineffectiveness of the antioxidant defense system in controlling plasma lipid peroxide content. Increased amounts of thiobarbituric acid-reactive material could have been the result of spillover from increased tissue peroxidation or the presence of pro-oxidants in malarial plasma.

Altered plasma lipid pattern in falciparum malaria.

Plasma levels of HDL, LDL, total cholesterol and triglycerides were measured in 60 patients with falciparum malaria (37 severe cases and 23 mild) and in 83 healthy individuals, to study malaria-induced changes in plasma lipids. Triglyceride levels were lower in the patients than in the controls but the difference was significant only for those with severe malaria (P < 0.001). In contrast, the levels of all the other plasma lipids were significantly higher (P < 0.001) in those with severe malaria than in those with mild malaria, and in the mild malaria cases compared with the controls. Initially LDL cholesterol was estimated by the Friedwald formula, but this gave negative values in a few cases of severe malaria. Plasma lipoproteins were therefore also measured by nephelometry; the estimated levels of S particles, corresponding to LDL, were then found to be lower in all malaria cases than in the controls (P < 0.001) but never negative. Interestingly, levels of L particles in the patients with severe malaria were significantly elevated compared with the other patients and controls (P < 0.001), indicating impaired metabolism of chylomicrons. Plasma albumin, considered a negative acute phase protein (i.e. its level decreases as a consequence of the acute phase response), was reduced significantly and was directly correlated to HDL cholesterol levels (r = 0.715 and r = 0.895, respectively) in both mild and severe malaria. Follow-up of 22 of the severe malaria cases three weeks after treatment indicated that, while triglycerides had returned to similar levels to those in the controls, total cholesterol levels were still elevated and could give misleading results if lipid profiles were used, immediately after malaria infection, to assess an individual's risk of developing atherosclerosis.

Hepatic changes in P. falciparum malaria.

Liver function tests were performed in 165 hospitalized patients suffering from P. falciparum malaria with complications. Serum bilirubin was found increased in 33 patients, and 22 of them had unconjugated hyperbilirubinaemia. Serum alanine aminotransferase was increased in 5 patients, but only to mild to moderate levels. Serum alkaline phosphatase was increased in 11 patients, gamma-glutamyl transpeptidase in 3 patients. Serum total protein and albumin were significantly decreased but these were considered more as indicator of acute phase response. Liver cell necrosis was observed in one patient, and oedema and mononuclear cell infiltration in two patients. Though hepatomegaly and mild elevation of enzymes can be observed in a significant proportion of patients, involvement of liver leading to acute hepatitis or liver cell necrosis is a relatively uncommon complication in P. falciparum malaria.

Influence of serum albumin & total protein on fructosamine measurement.

To assess the effect of serum albumin and total protein on the fructosamine level 57 hypoalbuminaemic patients (serum albumin less than 30 g/1), of whom 44 were nondiabetics and 13 were diabetics, were studied. Fructosamine levels of hypoalbuminaemic diabetics was increased only marginally in comparison to healthy controls (P greater than 0.05) whereas in 122 other normalbuminaemic diabetics, the level was found to be significantly higher (P less than 0.001). In control subjects, the correlation between fructosamine and serum albumin (r = 0.69, P less than 0.001) was better than that of total protein (r = 0.42, P less than 0.01) whereas in hypoalbuminaemic patients the pattern was reversed (r = 0.51 and 0.59 respectively), indicating substantial contribution by the globulins. A working formula suggesting approximate contribution of each gram of albumin and globulin in healthy subjects was calculated. It is inferred that the use of serum fructosamine for assessment of glycaemic status could be misleading in patients with lower albumin values. Calculating serum fructosamine values from serum albumin alone in these patients is likely to be inaccurate, as it ignores the contribution of globulins which can be substantial in certain disease conditions. A gross idea regarding the glycaemic status can be obtained by comparing actual and calculated values of fructosamine from the formula.

Increased cerebrospinal fluid protein and lipid peroxidation products in patients with cerebral malaria.

Membrane lipid peroxidation by reactive oxygen species leading to increased capillary permeability is considered an important event in the pathogenesis of severe malaria. A significant decrease in plasma albumin and increases in cerebrospinal fluid (CSF) protein and malondialdehyde (MDA) were observed in 73 patients with cerebral malaria, compared to values in 23 control patients. The greatest effect was noticed in the most severely ill patients. The ratio of CSF protein to plasma albumin was increased in the patients compared to the controls, and in fatal cases of cerebral malaria compared to non-fatal cases. Brain necropsies showed oedema, fibrin deposits and mononuclear cell infiltration. It is proposed that cerebral oedema due to enhanced permeability of vascular endothelium induced by increased lipid peroxidation plays a crucial role in the causation of cerebral malaria.

Homozygous familial hypercholesterolaemia. Report of three cases.

Homozygous familial hypercholesterolaemia is a rare disorder encountered in one in a million in the general population. Case reports of three patients from two families are presented. A 25 year male presented with extensive myocardial infarction and had a fatal outcome. His younger brother (14 years), as also a 12 year girl from another family with multiple planar xanthomata and tuberose xanthomata, are presented.

Increased plasma lipid peroxidation in riboflavin-deficient, malaria-infected children.

Plasma lipid peroxides were measured as malonyldialdehyde (MDA) by the thiobarbituric acid (TBA) method in 75 children suffering from Plasmodium falciparum malaria. Their riboflavin status was assessed by measuring erythrocyte glutathione reductase activation coefficients (EGRACs), and values greater than 1.40 were regarded as indicating biochemical deficiency. Plasma MDA was higher (p less than 0.001) in patients than in control subjects; the concentrations were 3.65 +/- 0.70 and 1.77 +/- 0.45 mumol/L (means +/- SD), respectively. The riboflavin-deficient group had higher plasma MDA values (3.98 +/- 0.70 mumol/L) than did the nondeficient group (3.30 +/- 0.68 mumol/L, p less than 0.001). Plasma MDA concentrations correlated with EGRACs (r = 0.46, p less than 0.01) in the patients. It is proposed that riboflavin deficiency restricts regeneration of reduced glutathione making the parasitized erythrocytes more vulnerable to destructive lipid peroxidation and increasing plasma lipid hydroperoxides.

Hepatic morphology in reactional states of leprosy.

Liver function tests and liver biopsies were studied in 23 leprosy patients in reaction and 10 without reaction. The liver biopsies in leprosy patients with reaction showed exudative lesions, epithelioid and tuberculoid granulomas, and foam-cell granulomas. Portal vasculitis was encountered in a few cases. Neutrophilic infiltration into the foam-cell granulomas was seen in a few cases of lepromatous (LL) leprosy with reaction. In six cases of borderline (BL, BB and BT) leprosy with reaction, a spectrum of lesions bearing footprints of exudative lesions were seen evolving into epithelioid-cell granulomas. Foam-cell granulomas and tuberculoid and epithelioid granulomas along with exudative lesions were encountered in two cases on individual biopsy strips. An altered albumin-to-globulin ratio was the chief functional derangement observed in these cases. The spectrum of changes observed in borderline leprosy with reaction could be discrete steps in the evolution of upgrading reaction.

Riboflavin deficiency and severity of malaria.

The riboflavin status of 64 children suffering from malarial infection was assessed by measuring the activation coefficient of erythrocyte glutathione reductase. Thirty-five children were found to be deficient in riboflavin whereas in 29 children riboflavin status was within the normal range. The median parasite count and its range on admission in the deficient group (2.7 per cent, range 0.3-13.6) was lower than that in the non-deficient group (5.3 per cent, range 0.6-30.2). The correlation between activity coefficient and parasite count was significant (R = -0.49). The recovery process was slower in the deficient group even though they had a relatively lower parasite count. It is inferred that riboflavin deficiency leads to inhibition of growth and multiplication of plasmodia. Its beneficial effects in malaria infection needs further evaluation.

Hypoglycaemia in severe falciparum malaria.

The incidence of hypoglycaemia and the role of quinine in its causation was assessed in 46 patients with severe Plasmodium falciparum malaria. Plasma glucose and immunoreactive insulin were estimated before, during and after quinine therapy. In 5 patients the plasma glucose was in the hypoglycaemic range, the lowest value being 0.67 mmol/litre (12 mg/dl) in a pregnant patient. Most of the remaining patients showed a significant fall in plasma glucose (P less than 0.05), but not to the hypoglycaemic range, and an increase in plasma insulin after quinine (P less than 0.01). A good correlation was found between these changes (r = 0.79, P less than 0.01). Patients with severe P. falciparum malaria, particularly those on quinine therapy, should be watched carefully for developing hypoglycaemia.