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Biomedical subjects

Y N Rao

Publications and source records attributed to Y N Rao.

15 recordsLinked to original sources
PubMed2006

A comparison of optimal MIMO linear and nonlinear models for brain-machine interfaces.

The field of brain-machine interfaces requires the estimation of a mapping from spike trains collected in motor cortex areas to the hand kinematics of the behaving animal. This paper presents a systematic investigation of several linear (Wiener filter, LMS adaptive filters, gamma filter, subspace Wiener filters) and nonlinear models (time-delay neural network and local linear switching models) applied to datasets from two experiments in monkeys performing motor tasks (reaching for food and target hitting). Ensembles of 100-200 cortical neurons were simultaneously recorded in these experiments, and even larger neuronal samples are anticipated in the future. Due to the large size of the models (thousands of parameters), the major issue studied was the generalization performance. Every parameter of the models (not only the weights) was selected optimally using signal processing and machine learning techniques. The models were also compared statistically with respect to the Wiener filter as the baseline. Each of the optimization procedures produced improvements over that baseline for either one of the two datasets or both.

Action Potentials↗
PubMed2002

Antidiabetic and hypolipidemic activity of Helicteres isora in animal models.

Helicteres isora (Sterculiaceae) root juice has been used in the treatment of diabetes by several ethnic groups in different parts of India. A program was initiated to elucidate the scientific basis for the antidiabetic activity of H. isora. Ethanolic extract of H. isora root caused significant reduction in plasma glucose, triglyceride and insulin levels at 300 mg/kg dose after 9 days of administration to insulin resistant and diabetic C57BL/KsJdb/db mice. In normoglycemic and mildly hypertriglyceridemic Swiss albino mice, the extract also showed significant reduction in plasma triglyceride and insulin levels, without affecting plasma glucose level. An ethanolic extract showed activity distinctly different from glybenclamide and acarbose but similar to troglitazone in these models. In high fat fed hamster model, the extract showed significant reduction in plasma lipid levels. In order to identify the active pharmacophore, the ethanolic extract was further subjected to sequential partitioning with low, medium and high polarity solvents, which yielded a semipurified fraction having both euglycemic and lipid-lowering activity. Our study suggests that the extract of H. isora has insulin-sensitizing and hypolipidemic activity and has the potential for use in the treatment of type-2 diabetes.

Animals↗
PubMed1999

Antinociceptive and anti-inflammatory activity of carumbelloside-I isolated from Caralluma umbellata.

The phytochemical study using Caralluma umbellata (Asclepiadaceae) whole plant allowed the isolation of a novel pregnane glycoside named carumbelloside-I (3-O-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl-3beta,14beta -dihydroxypregn-5-en-20-one). Carumbelloside-I was evaluated for both antinociceptive activity and anti-inflammatory activity. The antinociceptive activity was evaluated in mice using the writhing test method, while the anti-inflammatory activity was evaluated in rats using the paw edema test with carrageenin. Carumbelloside-I has significant antinociceptive action. It has no anti-inflammatory activity.

Analgesics↗
PubMed1997

Acylated C-21 steroidal bisdesmosidic glycosides from Caraluma umbellata.

From the whole plant of Caraluma umbellata, three new C-21 steroidal glycosides, named as carumbellosides III-V, were isolated and their structures elucidated by extensive spectroscopic experiments, devoid of any derivatisation, as caralumagenin 3-O-beta-D-glucopyranosyl(1-->4)-beta-D-digitalopyranoside-20-O-be ta- D-glucopyranoside, caralumagenin 3-O-beta-D-glucopyranosy(1-->4)- beta-D-digitalopyranoside-20-O-(2-O- benzoyl)-beta-D-glucopyranoside and caralumagenin 3-O-[6-O-benzoyl-beta-D-glucopyranosyl(1-->4)]-beta-D- digitalopyranoside-20-O-(2-O-benzoyl)-beta-D-glucopyranoside. The determination of the absolute configuration of the aglycone as (20 R), the conformations of the sugars and the unambiguous assignments of their NMR spectroscopic signals were achieved by a combination of 2D-NMR techniques. The isolates were devoid of significant cytotoxity in the UIC human cancer cell panel.

Carbohydrate Conformation↗
PubMed1997

Effect of timing of cord clamping on the iron status of infants at 3 months.

OBJECTIVE: To determine the effect of timing of cord clamping on iron stores of term infants at 3 months of age. DESIGN: Prospective randomized clinical trial. SETTING: Tertiary hospital. SUBJECTS: 107 term neonates born to mothers with uncomplicated pregnancies and with hemoglobin more than 10 g/dl. METHODS: The 107 infants were randomized to either early (n = 48) or late (n = 59) clamping groups at the time of delivery. Outcome measures evaluated were serum ferritin and hemoglobin in the infant at 3 months age. RESULTS: The groups were comparable for maternal age, parity, weight, supplemental iron intake in pregnancy, infant's birth weight, gestation and sex. Maternal and cord ferritin and hemoglobin values at birth were comparable. The infant ferritin at 3 months were also similar. CONCLUSIONS: Iron stores at 3 months in term infants are not influenced by timing of cord clamping at birth.

Analysis of Variance↗
PubMed1994

Levels of erythrocyte malonyldialdehyde, vitamin E, reduced glutathione, G6PD activity & plasma urate in patients of pregnancy induced hypertension.

To assess the oxidative stress across the cell membrane in patients suffering from pregnancy induced hypertension, erythrocyte malonyldialdehyde, vitamin E, reduced glutathione, glucose-6-phosphate dehydrogenase activity and plasma urate levels were estimated in 25 non pregnant women, 40 normotensive pregnant women and 40 women with pregnancy induced hypertension (PIH). As compared to non pregnant women, there was a significant increase in the levels of erythrocyte malonyldialdehyde and plasma urate in normotensive pregnant women, which were further increased in women with PIH. Erythrocyte glutathione levels were raised in normotensive pregnant women as compared to non pregnant women. Its levels were decreased in patients of PIH as compared to normotensive pregnant women. Cellular bio-availability of vitamin E was depressed in both normotensive pregnancy as well as patients with pregnancy induced hypertension as compared to non pregnant women.

Adult↗
PubMed1993

Brain cholesterol and phospholipid levels in cyproheptadine treated albino rats.

Effect of different doses (2.5 mg, 5 mg, 10 mg and 40 mg/kg), s.c., for 2 weeks, of cyproheptadine (CYP) on brain cholesterol and phospholipid of albino rats was investigated. Cyp. 2.5 mg/kg, showed increase in brain cholesterol and phospholipid contents whereas other doses caused a decrease in phospholipid level.

Animals↗
PubMed1993

Serum enzyme abnormalities in protein energy malnutrition.

Six serum enzymes, alkaline phosphatase, cholinesterase, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase and gamma-glutamyl transpeptidase were studied in 30 cases of protein energy malnutrition (PEM). The mean serum values of alkaline phosphatase, cholinesterase and lactate dehydrogenase in cases of PEM were significantly lower than the controls, lowering being maximum in PEM Grade IV. The mean serum values of aspartate aminotransferase and alanine aminotransferase in patients with PEM were significantly higher than the controls. The mean serum values of gamma-glutamyl transpeptidase showed similar significant rise in all but PEM Grade IV. The degree of increase in the serum values of these three enzymes were maximum in cases with PEM Grade I. These findings suggest that abnormalities in blood levels of these enzymes occur in any form of PEM and these are related to the severity of the disease.

Adolescent↗
PubMed1992

Lymphocyte adenosine deaminase activity (L-ADA) in leprosy, during and after treatment of reactions.

Twenty-five patients with type 1 (lepra) and type 2 (E.N.L.) leprosy reactions were studied for lymphocyte adenosine deaminase activity (L-ADA), during and after treatment of the reactions, using a standard technique, in order to establish its pattern and if possible, its value in assessing the course of reactions. The results were compared with those from 30 control subjects, comprising 10 normal healthy adults, 10 patients with borderline tuberculoid (BT) leprosy, four patients with borderline lepromatous (BL) leprosy and six patients with lepromatous (LL) leprosy. The level of L-ADA in the leprosy controls was higher than that of normal healthy subjects. The L-ADA values in patients with different types of reactions were about 10-fold higher than those obtained from leprosy controls, emphasizing a possible role in assessing reactions in leprosy. However, there was no significant variation in L-ADA levels, either between the various leprosy controls or reaction groups, before and after treatment.

Adenosine Deaminase↗
PubMed1992

Isolation of Getah virus from mosquitos collected on Hainan Island, China, and results of a serosurvey.

An isolate of Getah virus was obtained from Culex mosquitos collected in Mao'an Village, Baoting County, Hainan Province, China, in 1964. The virus (strain M-1) replicated in laboratory-bred Aedes aegypti and Cx. fatigans (= quinquefasciatus), and was transmitted by laboratory-bred Ae. albopictus to healthy newborn albino mice. Skeletal muscles of newborn albino mice experimentally infected with the virus showed degeneration, atrophy, necrosis, and inflammatory changes of muscle fibers. Antibody prevalence in humans and animals ranged from 10.3% by neutralization tests of samples from healthy people in 1979 to 26.4% by CF tests of samples from people with febrile illnesses in 1982. The high prevalence of antibody in pigs, horses, and goats (17.6% to 37.5%) indicated that infection with Getah or a closely related virus is relatively common in domestic animals.

Adolescent↗