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Biomedical subjects

B N Roy

Publications and source records attributed to B N Roy.

35 records · Page 2Linked to original sources
PubMed1975

Maximum permissible weight to be carried on the head by a male worker from eastern India.

Six healthy adult male Indian workers whose physical characteristics resembled those of the average worker from eastern India, were required to carry compact loads of 20, 30, 40, and 50 kg at a speed of 5 km/h on separate days. From observations on energy expenditures, of peak pulse rates, and of the patterns of recovery pulse rates, it was decided that for the average eastern Indian male worker the permissible weight of a compact load for manual carriage on a hard, level terrain should not ordinarily be more than 30 kg.

Fatigue↗
PubMedDate not supplied

Photodynamic endometrial ablation in the nonhuman primate.

OBJECTIVE: To test the effectiveness of 5-aminolevulinic acid (ALA)-induced photodynamic endometrial ablation in the rhesus monkey under varying conditions of light delivery (fractionated versus continuous) and steroid priming. METHODS: Photodynamic endometrial ablation was carried out in 17 rhesus monkeys that were either postmenopausal or in the early proliferative phase. Four hours after intralumenal injection of ALA (250 mg in 1 mL hyskon), a quartz fiber with a diffusing tip was inserted. A KTP tunable dye laser delivered 300 mW of light (635 nm) for 60 minutes in either continuous or fractionated fashion (20 minutes on, 5 minutes off, and 40 minutes on). In some experiments, thermistors were used to monitor temperature in the lumen and myometrium during light treatment. Hysterectomy was performed 3 or 4 days after treatment, and endometrial damage was assessed histologically. Two additional monkeys (one rhesus and one cynomolgus monkey) were exposed to the same protocol, except hyskon was substituted for ALA to control for potential ablative effects due to light treatment alone. RESULTS: Endometrial ablation was evident in all ALA-photosensitized specimens. The degree of ablation around the light fiber ranged from moderate to complete. The depth of ablation ranged from 1.14 +/- 0.54 to 2.15 +/- 1.62 mm (mean +/- standard deviation). Ablation was most complete in uteri of menopausal monkeys. Light treatment after ALA increased lumenal temperature from 36 C to 50 C, whereas temperature was not significantly increased by light treatment in the controls. CONCLUSION: This is the first report of endometrial destruction in the primate using a photodynamic approach. Whereas clinical application of photodynamic therapy (PDT) requires complete endometrial ablation to produce long-lasting amenorrhea, our results suggest that PDT may offer a simple office-based approach to endometrial ablation.

Aminolevulinic Acid↗
PubMedDate not supplied

Effect of 5-aminolevulinic acid dose and estrogen on protoporphyrin IX concentrations in the rat uterus.

OBJECTIVES: To determine the in vivo dose-response relation between administered 5-aminolevulinic acid (ALA) and the concentration of protoporphyrin IX (PpIX) produced in rat uterine tissue, to determine the effect of estrogen on ALA-induced PpIX production in the rat endometrium and myometrium, and to determine the selectivity of ALA-induced PpIX production in uterine tissue. METHODS: Ovary-intact female rats (n = 53) received a subcutaneous estradiol-17 beta (E2) implant. Three days later, ALA dissolved in saline (0, 1, 2.5, 10, 25, or 50 mg/100 microL) was injected into one uterine horn. Three hours after ALA administration, the uterus was removed and the endometrium was scraped from the myometrium. In a second study, rats (n = 35) were ovariectomized and 8 days later given either an E2 or sham implant. After 3 days of hormonal or sham priming, ALA (10 or 25 mg) was injected into the uterine horn 3 hours before hysterectomy. In both studies, PpIX was extracted in a methanol/ perchloric acid (1:1) solution and quantified spectrofluorometrically. RESULTS: Five-aminolevulinic acid increased PpIX concentrations in the endometrium and myometrium in a dose-dependent fashion. Twenty-five milligrams of ALA produced maximum PpIX concentrations in both the endometrium and myometrium. In the second study, sham-implanted ovariectomized rats had endometrial PpIX concentrations approximately two times higher than those in the estrogen-primed rats after doses of either 10 or 25 mg ALA. In the third study, the endometrium had two to three times higher PpIX concentrations than the myometrium at 1, 10, 25, and 50 mg of ALA. CONCLUSIONS: An in vivo dose-response relation was demonstrated between ALA and uterine production of PpIX, with maximum PpIX concentrations occurring after 25 mg of intrauterine ALA. Because estrogen was not required to convert ALA to PpIX, complete endometrial ablation may best be achieved with an unstimulated endometrium.

Aminolevulinic Acid↗
PubMedDate not supplied

Intrauterine 5-aminolevulinic acid induces selective endometrial fluorescence in the rhesus and cynomolgus monkey.

OBJECTIVES: To evaluate the selectivity of endometrial photosensitization after intrauterine 5-aminolevulinic acid administration in nonhuman primates, and to assess acute and chronic systemic toxicity after intravenous (i.v.) delivery of 5-aminolevulinic acid. METHODS: Ovariectomized cynomolgus monkeys (n = 19) aged 6-18 years and ovariectomized rheusus monkeys (n = 3) aged 9-14 years were used in these studies, 5-aminolevulinic acid at various doses was administered by a transfundal (n = 8), transcervical (n = 3), or i.v. (n = 11) route. Spectrophoto-fluorometric readings and fluorescence microscopy were used to assess 5-aminolevulinic acid-induced photosensitization of uterine tissues; respiration, heart rate, blood biochemistry, and behavior were used to evaluate potential acute and delayed systemic toxicity. RESULTS: Endometrial fluorescence was achieved in all animals after administration of 5-aminolevulinic acid. Characteristic spectrophotofluorescence peaks of protoporphyrin IX (PpIX) in the endometrium but not myometrium confirmed selective endometrial PpIX production from 5-aminolevulinic acid. A transient (less than 1 week) increase in serum aspartate aminotransferase was observed after systemic instillation of 5-aminolevulinic acid in dosages 24-50-fold greater than that required to induce endometrial photosensitization after intrauterine injection. CONCLUSIONS: The endometrium but not myometrium in nonhuman primates is capable of converting 5-aminolevulinic acid into protoporphyrin IX. At large doses, systemic 5-aminolevulinic acid causes a transient increase in the serum aspartate aminotransferase level. No other evidence of acute or delayed systemic toxicity was observed.

Aminolevulinic Acid↗