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Biomedical subjects

V Saini

Publications and source records attributed to V Saini.

At least 19 recordsLinked to original sources
PubMed2004

Tunable optical properties of colloidal quantum dots in electrolytic environments.

The absorption spectra of colloidal cadmium sulfide quantum dots in electrolytic solutions are found to manifest a shift in the absorption threshold as the concentration of the electrolyte is varied. These results are consistent with a shift in the absorption threshold that would be caused by electrolytic screening of the field caused by the intrinsic spontaneous polarisation of these würtzite structured quantum dots. These electrolyte-dependent absorption properties provide a potential means of gaining insights on the variable extracellular and intracellular electrolytic concentrations that are present in biological systems.

Journal Article↗
PubMed1999

Activation of the Ras-GRF/CDC25Mm exchange factor by lysophosphatidic acid.

The Ras-GRF exchange factor can activate Ras-dependent responses following the activation of heterotrimeric G-protein and calcium signalling. In stable lines of NIH-3T3 fibroblasts that express Ras-GRF, the agonist lysophosphatidic acid (LPA) increases the phosphorylation state and activity of Ras-GRF. The stimulation of Ras-GRF can be demonstrated in vitro, in an assay using recombinant Ras substrate, and in situ, by a selective increase in the ability of LPA to stimulate mitogen-activated protein (MAP) kinase. The increase in Ras-GRF phosphorylation state, which occurs on serine residues, and the increase in exchange factor activity are blocked by pretreatment with pertussis toxin. Activation of Ras-GRF by LPA can also be inhibited by chelation of intracellular calcium and treatment of the Ras-GRF with protein phosphatase 1 (PP1), supporting a model in which Ras-GRF serves to integrate signals from multiple transduction pathways.

3T3 Cells↗
PubMed1995

EEG bispectrum predicts movement during thiopental/isoflurane anesthesia.

OBJECTIVE: The objective of our study was to test the efficacy of the bispectral index (BIS) compared with spectral edge frequency (SEF), relative delta power, median frequency, and a combined univariate power spectral derivative in predicting movement to incision during isoflurane/oxygen anesthesia. METHODS: A total of 42 consenting patients were assigned to 3 groups, isoflurane 0.75, 1.0, and 1.25 minimal alveolar concentration (MAC). Anesthesia was induced with thiopental and maintained with the appropriate end-tidal concentration of isoflurane. The electroencephalogram (EEG) was recorded using a microcomputer system, and data were analyzed off-line. The EEG during the 2 min before incision was analyzed. Following skin incision, each patient was carefully observed for 60 sec to detect occurrence of purposeful movement. RESULTS: For all groups combined, there was a statistically significant difference for BIS (p < 0.0001) and also for relative delta power (p < 0.016) between movers and nonmovers. There was a statistically significant difference between movers and nonmovers at 1.25 MAC isoflurane for BIS (p < 0.01). There were no other significant differences for any other EEG variable at any concentration of isoflurane. No EEG variable showed a relationship to isoflurane concentration. CONCLUSIONS: When bispectral analysis of the EEG was used to develop a retrospectively determined index, there was an association of the index with movement. Thus, it may be a useful predictor of whether patients will move in response to skin incision during anesthesia with isoflurane/oxygen.

Adult↗
PubMed1995

Attitudes of future mothers regarding infant feeding.

Attitudes of 2500 urban college girls from Ludhiana city, aged 15 to 20 years were assessed towards infant feeding using a standardized Likert Scale (r = 0.82). The influence of subject opted in college and the presence of a child less than 3 years in the family on the attitudes was also studied. The overall attitudes of the whole group towards infant feeding were negative. Science students had better attitude scores on most of the themes tested (p < 0.05). The presence of a child aged less than 3 years in the family had no significant influence on the attitudes of girls towards infant feeding. Most of the girls were desirous of studying the concepts of infant feeding in their college curriculum. It is recommended that efforts should be made to incorporate these concepts in the formal educational curriculum so that girls grow up with positive attitude towards infant feeding.

Adolescent↗
PubMed1992

Acute respiratory infections in children: a study of knowledge and practices of mothers in rural Haryana.

In the present study, data were collected on knowledge and practices of mothers in two villages of Block Beri of district Rohtak for devising a standard management plan. In all 304 mothers were interviewed. About 23 per cent mothers recognised pneumonia by fast breathing and 11.2 per cent recognised severe pneumonia by chest indrawing. Only 1.3 per cent mothers knew infective origin of ARI. Although most of them were convinced about continuation of breast feeding, 70 per cent of them were advising food restriction. Use of herbal tea in ARI was widely prevalent and so was the practice of putting warm mustard oil in ear for curing ear pain. Primary Health Centre was the most frequented place for treatment of ARI and mother-in-law was the most important person in taking management decisions for the child.

Acute Disease↗
PubMed1989

Reproducibility of exercise-induced ventricular arrhythmia in patients undergoing evaluation for malignant ventricular arrhythmia.

In patients with malignant ventricular arrhythmia, the utility of exercise testing for exposing arrhythmias and guiding antiarrhythmic drug selection and dosage is not yet generally accepted. A major reservation relates to the issue of reproducibility of arrhythmia provocation. This prospective study comprised 28 patients referred for evaluation of ventricular arrhythmia. In half of these subjects the clinical arrhythmia was sustained ventricular tachycardia or ventricular fibrillation. Maximal exercise testing adhering to a Bruce protocol was performed on 2 separate days. No antiarrhythmic drugs were administered at the time of testing. Of the 28 patients, 27 had an increase in arrhythmia with exercise. The prevalence rates of arrhythmia were greater than 80% and did not significantly differ between test 1 and test 2. Excluding infrequent single ventricular premature complexes, the reproducibility of a test with positive outcome was 76%. Similarly, test-retest agreement, a bidirectional measure of reproducibility, was greater than 74%. Kappa coefficients ranged from 0.26 to 0.36 for all grades of arrhythmia, indicating that reproducibility was consistently greater than by chance alone. Linear regression analysis of arrhythmia frequency in the 2 tests yielded R values of 0.76 to 0.96 and slopes of 0.82 to 1.2. No patient had enough spontaneous variability in repetitive forms to suggest spurious efficacy or aggravation. For ventricular premature complexes there was an 8 to 14% incidence of spurious efficacy and a 4 to 7% incidence of spurious aggravation. These results suggest that exercise-induced ventricular arrhythmia is sufficiently reproducible to serve as an adjunct method in the evaluation and management of patients with potentially life-threatening ventricular arrhythmias.

Adult↗
PubMed1989

Encainide and flecainide: are they interchangeable?

Encainide and flecainide are two recently released class IC antiarrhythmic agents that have been reported to be highly effective for suppressing all forms of ventricular arrhythmias. Both drugs are potent blockers of the sodium channel and produce marked slowing of conduction within the His-Purkinje system and myocardium. To establish if the response to one agent predicts the response to the other, the antiarrhythmic effect of the two drugs was compared in a group of 18 patients with malignant ventricular arrhythmia. Fourteen patients had sustained ventricular tachycardia and four patients had ventricular fibrillation. The average ejection fraction of this group was 37%. All patients had a high density of spontaneous ventricular arrhythmia and were evaluated noninvasively. Both drugs significantly reduced all forms of spontaneous arrhythmia. By Holter monitoring criteria, the effect of the two drugs was concordant in 61% (p = NS). By exercise criteria, the concordance rate was 50% (p = NS). Overall, 12 patients (67%) responded to encainide and eight (44%) patients responded to flecainide (p = NS). Only 10 of 18 (56%) patients had the same response to both agents (p = NS). There was no significant difference in ejection fraction or in average daily dose of drug between responders and nonresponders. Thus despite their similar electrophysiologic profile, the clinical antiarrhythmic effect of these two agents was different. For the noninvasive management of patients the response to one agent should not be used to predict the response to the other.

Adolescent↗
PubMed1989

Comparative effects of the opioids fentanyl and buprenorphine on ventricular vulnerability during acute coronary artery occlusion.

Fentanyl, a mu selective opioid agonist in wide clinical use, raises the ventricular fibrillation threshold in the normal canine myocardium. We have previously shown that this effect is amplified by haemorrhagic stress. In order to determine if mu receptor activation is antifibrillatory during acute myocardial ischaemia, we compared the effects of two mu selective agents, fentanyl and buprenorphine, in open chest chloralose anaesthetised dogs. Each drug was administered intravenously in two doses 1 h apart (fentanyl 30 micrograms.kg-1.dose; buprenorphine 0.3 mg.kg-1.dose). Ventricular fibrillation threshold was measured during right ventricular pacing using the single stimulus technique. The threshold was determined before and during a 10 min left anterior descending coronary artery occlusion. Prior to fentanyl administration, ventricular fibrillation threshold decreased from a control value of 19(SEM 2) mA to 12(1) mA during coronary artery occlusion. After the first dose of this drug an attenuation in the ischaemia induced fall in fibrillation threshold from 23(4) mA to 15(2) mA was observed. After the second dose of fentanyl the decline in fibrillation threshold was significantly blunted at 22(4) mA during control and 18(3) mA during occlusion, p less than 0.05 compared to no drug. In an additional series of experiments atropine sulphate abolished the antifibrillatory action of fentanyl, indicating that vagal efferent activation is responsible for the protective effect of the drug during acute myocardial ischaemia. This is in contrast with its mode of action during haemorrhage, when it enhances vagal afferent inhibition of sympathetic tone, and atropine pretreatment is without effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Antifibrillatory action of the narcotic agonist fentanyl.

Morphine, an opiate alkaloid with mixed mu- and delta-agonist properties, raises the ventricular fibrillation threshold in anesthetized dogs by altering autonomic tone. To elucidate further underlying structure-activity relationships, the effect of fentanyl, a nonalkaloid, mu-selective agonist in wide clinical use, was studied. Fentanyl (30 micrograms/kg) was given intravenously to 27 chloralose-anesthetized dogs, and ventricular fibrillation threshold was measured by means of the single-stimulus technique. In the baseline state fentanyl raised the ventricular fibrillation threshold by 14%. When the dogs were subjected to hemorrhagic stress, this effect was amplified to 29% (p less than 0.0001). Bilateral cervical vagotomy abolished fentanyl's antifibrillatory effect, but neither atropine sulfate (0.4 mg/kg/hr) nor atropine methylnitrate (0.5 mg/kg/hr) did so. Fentanyl's influence on the fibrillation threshold during hemorrhage was significantly reduced by bilateral stellate ganglionectomy (p less than 0.005). It is concluded that fentanyl raises the ventricular fibrillation threshold by its known sympathoinhibitory action rather than by its vagal efferent activating effect. The facts that an intact vagus is required and that hemorrhage amplifies the effect suggest that the antifibrillatory effect of fentanyl is mediated through the afferent component of the baroreflex arc.

Animals↗
PubMed1983

Clinical significance of short-term variability computed from heart-rate waveforms.

The significance of short-term variability (STV) of the baseline fetal heart rate (FHR) as a prime indicator of fetal well-being is well recognized. It is obvious that for consistently reliable assessment of short-term variability, objective quantification is a necessity. This paper presents a retrospective clinical evaluation of a new technique of STV quantification in terms of beats per minute derived from the slowly varying instantaneous FHR waveform rather than from the relatively rapidly varying fetal ECG. FHR signals from 45 patients, internally monitored during labor, were digitized onto IBM-compatible 9-track digital magnetic tape using a PERKIN-ELMER model 7/32 minicomputer at a sampling rate of 240 milliseconds. The digitized signals were then analyzed off-line for STV and FHR. For each patient about 600 clinical variables were entered into the computer and these data were utilized to comprehensively evaluate the neonatal outcome according to HOBEL's neonatal risk assessment system. The values of mean STV ranged from 1.21 b.p.m. to 6.47 b.p.m. with a median value of 2.75 b.p.m., which was used to divide the patient population into a low-variability (less than or equal to 2.75 b.p.m.) and a high-variability (greater than 2.75 b.p.m.) group. This was found to be justified as the STUDENTS's t-test on mean baseline STV values for these two populations showed them to differ significantly (P less than 0.001). Analysis of the results (Fig. 1) showed that 28.7% of the low-variability population were associated with a poor outcome compared with 4.3% in the high-variability group.(ABSTRACT TRUNCATED AT 250 WORDS)

Apgar Score↗
PubMedDate not supplied

Poisoning in children: Indian scenario.

The retrospective data on childhood poisoning from eight regional hospitals in India has been reviewed. The demographic features and types of poisonings encountered have been compared. The analysis of the data indicated that pediatric poisonings constituted 0.23-3.3% of the total poisoning. The mortality ranged from 0.64-11.6% with highest being from Shimla. Accidental poisoning was common involving 50-90% of children below 5 years of age and males outnumbered the females. Suicidal poisoning was seen after 13 years of age and was due to drugs and household chemicals. One of the hospitals in Delhi recorded a very high incidence (66.6%) of drug poisoning in children. The drugs consumed belonged to phenothiazines, antiepileptics and antipyretics. Iron poisoning was seen in younger children. Kerosene was one of the causes of accidental poisoning at all hospitals except Shimla and rural Maharashtra were probably wood charcoal is widely used. Pesticide poisoning was more prevalent in Punjab and West Bengal whereas plant poisoning was very common in Shimla. Significant number of snake envenomation has been recorded from rural Maharashtra. Other less common accidental poisonings in children included alcohol, corrosives, heavy metals, rodenticides, detergents and disinfectants. Thus various regions in the country showed some variation in types and frequency of childhood poisoning which could be attributed to different geographical and socio-economic background.

Adolescent↗