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Biomedical subjects

K Girish

Publications and source records attributed to K Girish.

7 recordsLinked to original sources
PubMed2004

Role of surface activity in the biological actions of ranitidine and famotidine.

The role of surface activity has been studied in the biological actions of ranitidine (RNT) and famotidine (FMT). The drugs have been shown to generate liquid membranes in series with a supporting membrane with the virtue of their amphiphilicity. Transport of histamine, acetylcholine, and ions (chloride, bicarbonate, potassium, sodium and calcium) have been studied in the presence of liquid membranes generated by surface-active RNT and FMT. The data on the modifications in the permeability of histamine, acetylcholine and ions indicate that the liquid membranes generated by RNT and FMT may play a significant role in their biological action. The surface-active nature of the drugs has been discussed with relevance to their pharmacological effects.

Acetylcholine↗
PubMed2004

Effect of ECT stimulus parameters on seizure physiology and outcome.

This study examined the effect of low- and high-pulse frequency stimulus electroconvulsive therapy on seizure physiology and therapeutic outcome. Forty depressed patients randomly received either low (n = 19) or high (n = 21) pulse frequency stimulus during a course of right unilateral electroconvulsive therapy. The current and pulse width were kept constant whereas the duration was proportionately varied. The two groups were compared for seizure parameters and therapeutic outcome. Low frequency stimulus group had lower threshold and less subconvulsive stimulation. There were no differences in seizure durations, ictal cardiovascular responses and therapeutic outcome between the two groups. Low frequency stimulus produced seizure at lower stimulus dose without affecting seizure parameters and therapeutic effects.

Adult↗
PubMed2003

Seizure threshold in ECT: effect of stimulus pulse frequency.

SUMMARY: Stimulus parameters, such as pulse width, frequency, and stimulus train duration, affect seizure threshold in electroconvulsive therapy (ECT), although variably. This study examined the effect of low- and high-pulse frequencies of stimulus on seizure threshold and physiological responses to ECT. Twenty-four consenting inpatients prescribed ECT by the treating psychiatrist received bilateral ECT. Threshold was reassessed at second and third ECT sessions in a crossover design. In the second ECT the pulse frequency was randomly either 50 pulses per second (PPS; n=13) or 200 PPS (n=11). In the third ECT, the same was reversed. The seizure threshold and number of subconvulsive stimulations were significantly lower with 50 PPS compared with 200 PPS. There was no significant difference in the cardiovascular responses between the two groups. Lower stimulus frequency is more efficient in inducing a seizure (smaller threshold) without compromising the physiological responses to ECT. Clinical effects of different doses of ECT stimulus must also consider the role of charge rate (frequency of pulses).

Adolescent↗
PubMed2000

Seizure threshold estimation by formula method: a prospective study in unilateral ECT.

Formula methods of estimating seizure threshold in bilateral electroconvulsive therapy (ECT) have been successful in 75% (at the first ECT) and 80% (at the sixth ECT) of treatments (Gangadhar et al., 1998). This study showed the same results for unilateral (UL) ECT patients. Its aim was to compare formula and titration methods for threshold determination. The seizure threshold (dependent variable) was determined by the titration method used at the first ECT in consecutive consenting patients (n = 80) prescribed UL ECT under general anesthesia. The independent variables were age, gender, diagnosis, illness severity, concurrent drugs, head circumference, and inion-nasion distance. Forward, step-wise, linear regression analysis showed age as the only significant predictor of seizure threshold (15% of variance). A formula based on regression analysis was prospectively applied in an independent sample (n = 30) of patients receiving UL ECT using the titration method for threshold determination. The results calculated a higher threshold than the actual threshold used in 14 patients, a threshold level in 8 patients, and below threshold in 8 patients. Formula-based estimates would have been successful in 22 (73%) patients, but the majority of them would have received higher than the recommended stimulus dose. Titration is the method preferred for clinical use. However, if a patient's doctor wishes to use the formula-based method, he or she should do so with specific considerations.

Adult↗
PubMed1998

Acute post-ECT cardiovascular response: a comparison of threshold right unilateral and bilateral ECT.

The effect of electrode placement on cardiovascular responses was studied. Rate pressure product and diastolic blood pressure before anesthesia and 30 s after electroconvulsive therapy (ECT) seizure were recorded. Recordings were made at the first (threshold ECT) session in 124 bilateral ECT (BLECT) and 95 unilateral ECT (ULECT) consenting patients. Postictal rate pressure product (RPP) was significantly higher after BLECT than ULECT. Mean increase in RPP from pre- to postictal phase was 31% in the former. The corresponding change with ULECT (20%) was significantly smaller. In the stepwise, multiple regression model, pre-ECT RPP, age, and stimulus laterality significantly contributed to postictal RPP. No cardiovascular complications occurred in any of the 219 ECT sessions.

Adult↗
PubMed1998

Formula method for stimulus setting in bilateral electroconvulsive therapy: relevance of age.

Seizure thresholds were determined by titration in consecutive electroconvulsive therapy (ECT) patients at the first (n = 146) and sixth (N = 83) ECT sessions. Equations to predict the threshold at the first and sixth ECT were computed from these data using a stepwise linear regression model. These equations were tested prospectively at the first ECT (n = 48) and sixth ECT (n = 26) sessions. Stimulus dose derived from the corresponding equations yielded adequate seizure (successful) in 82% and 84% of patients, respectively. Predictions based on age alone (disregarding two other significant variables--illness severity and inion-nasion distance) were estimated at these two ECT sessions. This would not appreciably compromise the success rate. The "formula" method using age alone may therefore be used in routine clinical practice.

Adolescent↗