Pedunculated giant hemangioma of liver.
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Biomedical subjects
Publications and source records attributed to K Srinivasan.
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Baroreceptor reflex sensitivity, coherence functions, and transfer functions between respiration and heart rate, and between respiration and blood pressure, were studied in nine normal volunteers before and after intravenous sodium lactate infusions. Cross-spectral analysis was used to examine heart rate, finger blood pressure, and respiration obtained with the subjects in a supine posture during spontaneous breathing. Sodium lactate produced a significant decrease of the modulus between respiration and heart rate (beats/min/l). There was no such change for the placebo infusions. The absence of a significant difference in the modulus between systolic blood pressure and heart rate for placebo or lactate indicated that there were no significant changes in the baroreceptor sensitivity index. These findings suggest that lactate infusions are associated with a decrease in cardiac vagal function.
We have isolated and characterized human monoclonal antibody 2G12 to the gp120 surface glycoprotein of human immunodeficiency virus type 1 (HIV-1). This antibody potently and broadly neutralizes primary and T-cell line-adapted clade B strains of HIV-1 in a peripheral blood mononuclear cell-based assay and inhibits syncytium formation in the AA-2 cell line. Furthermore, 2G12 possesses neutralizing activity against strains from clade A but not from clade E. Complement- and antibody-dependent cellular cytotoxicity-activating functions of 2G12 were also defined. The gp120 epitope recognized by 2G12 was found to be distinctive; binding of 2G12 to LAI recombinant gp120 was abolished by amino acid substitutions removing N-linked carbohydrates in the C2, C3, V4, and C4 regions of gp120. This gp120 mutant recognition pattern has not previously been observed, indicating that the 2G12 epitope is unusual. consistent with this, antibodies able to block 2G12 binding to recombinant gp120 were not detected in significant quantities in 16 HIV-positive human serum samples.
A few common spices or their active principles, were examined for their possible influence on digestive enzymes of intestinal mucosa in experimental rat. The animals were fed the following diets for 8 weeks: control, curcumin (0.5%), capsaicin (15 mg%), piperine (20 mg%), ginger (50 mg%), cumin (1.25%), fenugreek (2%), mustard (250 mg%) and asafoetida (250 mg%). Dietary curcumin, capsaicin, piperine and ginger prominantly enhanced intestinal lipase activity and also the disaccharidases sucrase and maltase. Dietary cumin, fenugreek, mustard and asafoetida brought about decreases in the levels of phosphatases and sucrase. The positive influences of a good number of spices on these terminal enzymes of digestive process could be an additional feature of species that are generally well recognized to stimulate digestion.
Effect of feeding 0.5% curcumin diet or 1% cholesterol diet was examined in albino rats rendered diabetic with streptozotocin injection. Diabetic rats maintained on curcumin diet for 8 weeks excreted comparatively less amounts of albumin, urea, creatinine and inorganic phosphorus. Urinary excretion of the electrolytes sodium and potassium were also significantly lowered under curcumin treatment. Dietary curcumin also partially reversed the abnormalities in plasma albumin, urea, creatine and inorganic phosphorus in diabetic animals. On the other hand, glucose excretion or the fasting sugar level was unaffected by dietary curcumin and so also the body weights were not improved to any significant extent. Diabetic rats fed curcumin diet had a lowered relative liver weight at the end of the study compared to other diabetic groups. Diabetic rats fed a curcumin diet also showed lowered lipid peroxidation in plasma and urine when compared to other diabetic groups. The extent of lipid peroxidation on the other hand, was still higher in cholesterol fed diabetic groups compared to diabetic rats fed with control diet. Thus, the study reveals that curcumin feeding improves the metabolic status in diabetic conditions, despite no effect on hyperglycemic status or the body weights. The mechanism by which curcumin improves this situation is probably by virtue of its hypocholesterolemic influence, antioxidant nature and free radical scavenging property.
Some evidence suggests that patients with panic disorder have a decreased cardiac vagal and a relatively higher sympathetic activity. In this study, spectral analysis of the time series of heart rate before and after isoproterenol infusions was used to study heart rate variability in six panic disorder patients and 11 normal control subjects. These preliminary data reveal a significant increase of sympathovagal ratios only in the patient group after isoproterenol administration. The findings suggest a relative increase in cardiac sympathetic and a relative decrease in cardiac vagal function in patients with panic disorder during isoproterenol infusions.
Consumption of bitter gourd (Momordica charantia) by diabetic patients is a common practice in India, with the belief that it has an useful hypoglycemic potential. In the absence of conclusive information on the hypoglycemic influence of continuous intake of bitter gourd, in the present investigation, we have examined the hypoglycemic potency of dietary bitter gourd in experimentally induced diabetic rats. Wistar rats rendered hyperglycemic by streptozotocin (50 mg/kg b.w., i.p.) were maintained on a semi-synthetic diet containing freeze dried bitter gourd powder at 0.5% level for 6 weeks. The excretion of glucose, protein, urea and creatinine was monitored during the experimental period. Plasma glucose, albumin, urea and cholesterol were analysed at the end of the experimental regime. Dietary bitter gourd did not show any beneficial hypoglycemic influence as evidenced by the blood glucose levels as well as the excretion of diabetes related metabolites.
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Various roles for the viral receptor, CD4, have been proposed in facilitating human immunodeficiency virus type 1 (HIV-1) entry, including virion binding to the target cell and the induction of conformational changes in the viral envelope glycoproteins required for the membrane fusion reaction. Here, we compare the structural requirements in the CDR2-like loop of CD4 domain 1, the major contact site of the gp120 envelope glycoprotein, for gp120 binding and virus entry. For every CD4 mutant examined, the level of cell surface expression and the gp120 binding affinity were sufficient to explain the relative ability to function as a viral receptor. The decrease in relative infectibility associated with decreased gp120 binding affinity was more pronounced at lower cell surface CD4 concentrations. These results imply that both receptor density and affinity determine the efficiency of HIV-1 entry and that specific structures in the CD4 residues examined are probably not required for HIV-1 entry functions other than gp120 binding.
The influence of two varieties of betel leaf (Piper betle Linn.) namely, the pungent Mysore and non-pungent Ambadi, was examined on digestive enzymes of pancreas and intestinal mucosa and on bile secretion in experimental rats. The betel leaves were administered orally at two doses which were either comparable to human consumption level or 5 times this. The results indicated that while these betel leaves do not influence bile secretion and composition, they have a significant stimulatory influence on pancreatic lipase activity. Besides, the Ambadi variety of betel leaf has a positive stimulatory influence on intestinal digestive enzymes, especially lipase, amylase and disaccharidases. A slight lowering in the activity of these intestinal enzymes was seen when Mysore variety of betel leaf was administered, and this variety also had a negative effect on pancreatic amylase. Further, both the betel leaf varieties have shown decreasing influence on pancreatic trypsin and chymotrypsin activities.
Dried flower of A. alliaceum when fed at 2% level in diet for 6 weeks to experimental rats rendered hypercholesterolemic by cholesterol feeding, exhibited blood cholesterol lowering effect. Cholesterol lowering efficacy of these garlic smelling flowers was similar to garlic oil fed at 0.002% level. Animals fed A. alliaceum flowers excreted higher amounts of neutral and acidic sterols in faeces similar to onion or asafoetida fed (at 2% dietary level) rats. A. alliaceum significantly lowered the absorption of dietary cholesterol from intestine like other sulfur containing spices, viz. garlic oil, onion and asafoetida. It is inferred from this study that limitation in intestinal cholesterol absorption is responsible for cholesterol lowering effect of this flower in hypercholesterolemic animals.
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BACKGROUND: Rickettsialpox is caused by Rickettsia akari, which is transmitted from rodents to humans by bloodsucking mites. The initial skin lesion forms an eschar and is followed by the development of fever, malaise, myalgia, and 5 to 40 maculopapules and papulovesicles. The disease, which responds to tetracycline, can be mistaken for chickenpox. The diagnosis has been based on an increase in serum antibody titers against R. akari over a period of three to eight weeks. We discuss a more rapid technique that uses direct immunofluorescence to identify R. akari in paraffin-embedded tissue, and we describe the histopathological findings of lesional skin. METHODS: We studied 13 patients (age, 11 months to 58 years) who were seen at Lincoln Hospital in New York City from 1980 to 1989 and were suspected of having rickettsialpox. In nine patients serum samples were obtained during the acute and convalescent phases of the illness for indirect fluorescent-antibody testing. Punch-biopsy specimens of skin lesions were examined by microscopy and by direct fluorescent-antibody testing with an anti-R. rickettsii globulin conjugated with fluorescein isothiocyanate. RESULTS: The diagnosis was confirmed in all 13 patients by indirect or direct fluorescent-antibody techniques. Direct fluorescent-antibody testing of eschars from seven patients was positive in five patients, but negative in two patients who had serologically confirmed rickettsialpox. In contrast, direct fluorescent-antibody testing of papulovesicles from nine patients was positive in only one patient. Histopathological analysis of the eschars revealed extensive necrosis and inflammation. In biopsy specimens of papulovesicles, dermal edema, subepidermal vesicles, and vascular changes were present. CONCLUSIONS: The combination of direct fluorescent-antibody testing of an eschar from the presumed site of inoculation and histopathological examination of papulovesicles for distinctive features represents an improved method of diagnosing rickettsialpox.
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We used spectral analysis of heart rate (HR), blood pressure (BP), and respiration to examine the effects of lactate on cholinergic and adrenergic influences on HR and BP variability, a technique found to be very useful in cardiovascular research. We specifically used high frequency (0.2-0.5 Hz) and midfrequency (0.07-0.15 Hz) powers to study cholinergic and adrenergic activity in nine normal control subjects before and after lactate and placebo infusions. Our results demonstrate a marked decrease in cholinergic activity and a significant increase in sympathovagal ratios of HR modulation after lactate infusions. This altered sympathovagal balance may contribute to the panicogenic effects of lactate in panic disorder patients.
Previous reports on heart rate variability suggest that, compared to controls, panic disorder patients have a higher relative mid-frequency (MF) (0.07-0.15 Hz) power in standing posture and that they also have a greater increase in standing MF power after the administration of yohimbine. We studied the effects of nortriptyline, a tricyclic antidepressant, on HR variability measures in 13 panic disorder patients before and after successful treatment. There was a highly significant increase in supine and standing HR (p = 0.00001) while there was a significant decrease of standing absolute and relative MF power (p = 0.009 and 0.0001 respectively). This uncontrolled preliminary study suggests a decrease in sympathetic activity related to nortriptyline treatment in addition to its anticholinergic effects.
Using spectral analysis of the continuous time series signal before and during lactate and placebo infusions, the authors studied heart rate variability in six patients with panic disorder and nine normal comparison subjects. The decrease in high-frequency (0.20-0.50 Hz) power and the increase in sympathovagal ratios (mid-frequency [0.07-0.15 Hz] to high-frequency powers) after the administration of intravenous sodium lactate were significantly greater in the patients than in the normal subjects after correction of the values for the amount of lactate infused. This result suggests an exaggerated cardiac vagal withdrawal in patients with panic disorder during lactate infusions.
The question of whether, during the evolution of an enzyme, the transition state of the catalysed reaction is largely unchanged, or whether transition state and protein change together, was examined using the egb beta-galactosidases of Escherichia coli. Charge development at the first chemical state was assumed [Konstantinidis and Sinnott (1991) Biochem. J. 279, 587-593] to be proportional to delta delta G++, the ratio of second-order rate constants for the hydrolysis of beta-D-galactopyranosyl fluoride and 1-fluoro-D-galactopyranosyl fluoride, expressed as a free-energy difference. delta delta G++ (kJ.mol-1) falls from 10.4 for wild-type enzyme to 6.8 and 7.2 as a consequence of two different single amino-acid changes (which arise from single evolutionary events), to 6.3 as a consequence of the two amino-acid changes together, and then increases slightly to 7.3 as a consequence of a third single evolutionary change involving three further amino-acid changes.