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Biomedical subjects

S Dhingra

Publications and source records attributed to S Dhingra.

9 recordsLinked to original sources
PubMed2026

Reduced Length of ADT and ARTA With XRT in High-Risk Prostate Cancer (RELAX): A Randomised Controlled Trial.

AIM: To assess the efficacy of a short, intensified regimen of androgen deprivation therapy (ADT) and androgen receptor-targeted agent (ARTA) with curative-intent external beam radiotherapy (XRT) for high-risk prostate cancer (HRPCa) staged with prostate specific membrane antigen (PSMA) imaging. MATERIALS AND METHODS: The RELAX (Reduced Length of ADT and ARTA with XRT in high-risk prostate cancer) trial is a multicentre, phase II randomised non-inferiority trial comparing 9 months of ADT and 6 months of ARTA against the standard 24-month ADT, with definitive dose-escalated hypofractionated pelvic radiotherapy for PSMA-staged non-metastatic HRPCa. The primary endpoint is 5-year disease-free survival (DFS), defined from randomisation to first biochemical or clinico-radiological recurrence or any-cause death. Secondary endpoints include biochemical failure-free survival, metastasis-free survival, overall survival, testosterone recovery, treatment-related adverse effects, and patient-reported outcomes. Participants are monitored with serial serum PSA and testosterone levels, CTCAE and PRO-CTCAE assessments, and PSMA-PETCT at recurrence. The non-inferiority margin is set at 10% absolute difference from an expected 5-year DFS of 85% in the standard arm, with intention-to-treat analysis. The trial is ethics board approved and funded by institutional intramural grant, and registered on clinicaltrials.gov (NCT06818682). RESULTS: The planned accrual of 206 participants commenced in February 2025, with nearly a third of enrolment completed till date. CONCLUSION: The RELAX trial incorporates contemporary standards of PSMA-based staging, dose-escalated hypofractionated radiotherapy, and ARTA for HRPCa. The results are expected to inform the efficacy of a shorter, intensified androgen suppression strategy against the prevailing standard of long-term ADT for these patients.

Humans↗
PubMed1986

A comparison of the bronchodilating effects of a beta-2 adrenergic agent (albuterol) and an anticholinergic agent (ipratropium bromide), given by aerosol alone or in sequence.

We evaluated the effect of anticholinergic and beta-adrenergic inhaled bronchodilators, alone or in sequence, in 11 patients with chronic obstructive pulmonary disease. We compared the agents albuterol and ipratropium bromide when each was used as a single aerosol in the maximal dose. After giving a maximal dose of one agent, we compared the effect of adding the other with that of adding a placebo. When used alone, both bronchodilators significantly increased airflow and relieved hyperinflation, and there was no significant difference between the two. After the improvement with the initial bronchodilator, the subsequent effect of a second inhaled bronchodilator was not greater than that of placebo. These results suggest that in the treatment of chronic obstructive pulmonary disease, these two aerosols are usually equipotent in maximal doses and the addition of a second agent is of no practical value. The data support the prescription of a single inhaled agent in most cases but do not rule out the value of combinations of agents under special circumstances.

Aerosols↗
PubMed1979

Airway closure and closing volume.

Using boluses of radioactive Xe we compared regional N2O uptake with regional perfusion distribution during open glottis breath hold in five seated men. Measurements were made near residual volume, at closing volume (CV), above CV and when possible, between CV and residual volume (RV). At low lung volumes basal N2O uptake was small whereas basal blood flow was not. This discrepancy was interpreted as evidence of airway closure and was quantitated. All subjects showed extensive basal closure near RV. At closing volume four of five subjects demonstrated closure and some closure was evident in these subjects at volumes in excess of CV. The increase in airway closure with decreasing lung volume was much greater below CV than above it. Conventional CV tracings were obtained using helium boluses; the height of phase IV was positively correlated with the change in airway closure between CV and RV as assessed by the N2O technique. The slope of phase III did not correlate with the amount of airway closure measured at CV. We concluded that the conventionally measured CV is not the volume at which airway closure begins but that the onset of phase IV reflects an increase in basal airway closure and the height of phase IV reflects the amount of basal closure between CV and RV.

Adult↗
PubMed1978

Alkaline phosphatase activity in normal and denervated skeletal muscle.

Changes in the specific activity of alkaline phosphatase in the normal and denervated skeltal muscle have been studied both histochemically as well as biochemically for a maximum period of 8 weeks of its postnatal development. In the normal muscle, a heterogenous population of fibres with respect to the enzyme distribution is observed. Relatively higher levels of enzyme in the denervated muscle and also the proliferation of extrafibillar connective tissue in the diseased muscle show its specific association with the lytic processes.

Alkaline Phosphatase↗
PubMed1978

Ventilatory response to low levels of CO2.

Ventilation and Pa(CO2), were measured in six subjects after 10-12 min of breathing 1-2% CO2 during hyperoxia and hypoxia. These inspired CO2 concentrations were achieved in two ways: by enriching the inspirate with CO2 and by having the subjects breathe through dead spaces of 100-400 cm3. Breathing through dead space gave the same results as CO2 enrichment of the inspirate when the effect of the dead spaces on mean inspired CO2 was allowed for. During hyperoxia all subjects demonstrated isocapni hyperpnea in response to mean inspired CO2 concentrations of 1%; ventilation increased without change in PA(CO2). When mean inspired CO2 concentration approximated 1.5% two subjects showed isocapnic hyperpnea, and one subject demonstrated isocapnic hyperpnea in response to mean inspired CO2 concentrations of 2%. The increase in PA(CO2) observed in each subject in response to 2% CO2 in O2 correlated negatively with the slope of that subject's rebreathing CO2 response curve. Hypoxia (PA(O2Y = 45-50 mm Hg) depressed the response to 1% CO2 in that, while hypoxic, no subject showed isocapnic hyperpnea in response to 1% CO2. The isocapnic hyperpnea we observed was chiefly due to increased tidal volume, and was therefore not analogous to the isocapnic hyperpnea observed by others in dogs in response to increases of CO2 in lung gas. When low levels of CO2 produced an increase in PA(CO2) the associated change in ventilation (delta Ve/delta PA(CO2)was much less than that observed while rebreathing 7% CO2. Isocapnic hyperpnea in response to low levels of CO2 is common among normal individuals, and is depressed by hypoxia; the stimulus responsible for this response is unknown.

Adult↗
PubMed1978

Acid phosphatase activity in normal and denervated chick skeletal muscle.

Histochemical and biochemical changes in acid phosphatase activity were studied in the normal and denervated gastrocnemii of chick for a maximum period of 8 weeks. In the normal muscle, fibre heterogeneity with respect muscles exhibit greater susceptibility to degenerative changes on account of denervation. Quantitatively higher enzyme levels in the denervated muscles confirm the lytic role of acid phosphatase.

Acid Phosphatase↗
PubMed1978

Differential response to chick skeletal muscle to denervation. A histopathological study with reference to lipid and lipase distribution.

The effects of denervation on the three gastrocnemii muscle of chick have been studied with regard to the lipid and lipase distribution on the different fibre types, for a maximum period of 8 weeks after unilateral sciatectomy. The observations exhibit a loss of intrafibrillar lipids which is not on account of enhanced lipolytic activity within the muscle fibres. The lipases also exhibit lowered intrafibrillar activity during the corresponding period and may be one of the several lytic enzymes responsible for the degenerative changes in the muscle cells. The differential response of the three muscles, the muscle bundles in each of them and the different fibre types, to denervation, has been explained on the basis of the balance maintained between the trophic and the intrinsic regulatory mechanisms.

Animals↗