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Biomedical subjects

D Hamilton

Publications and source records attributed to D Hamilton.

61 records · Page 4Linked to original sources
PubMedDate not supplied

Experimental laser phototherapy of the Morris 7777 hepatoma in the rat.

The tumoricidal effect of the activation of hematoporphyrin derivative (HpD), by an argon-ion-dye-laser (wavelength 630 nm), was investigated in the Buffalo rat bearing subcutaneous implants of the Morris 7777 hepatoma. Tumor growth was monitored by measuring the tumor volume with constant force calipers. In control animals and those that were pretreated with HpD alone (10 or 20 mg per kg by i.p. injection) or laser light alone (2,000 J at 100 mW), a predictable exponential growth pattern of the cancer was observed. Animals were pretreated with HpD (10 mg per kg by i.p. injection) 48 hr prior to the fiberoptic, intratumor delivery of laser radiation (2,000 J at 100 mW), when the tumor had reached a volume greater than 1.5 cm3. Forty-eight hours after combined laser and HpD treatment, the hepatoma underwent coagulation necrosis, and the tumor volume rapidly increased from a mean value of 1.8 +/- 0.7 cm3 S.D. to a value of 5.8 +/- 1.5 cm3 S.D., compared with a mean of 3.7 +/- 0.7 cm3 S.D. in animals who had not received laser phototherapy. Rats treated with HpD and laser light survived longer (mean survival time 48 +/- 12 days S.D.) than did the other animals treated with the laser alone or HpD alone (mean survival time 31 +/- 16.5 S.D.). Tissue biodistribution studies with tritiated hematoporphyrin derivative, given with doses of 10 and 20 mg per kg of HpD, showed higher concentrations of the dye in the liver, kidneys and spleen than in the tumor at 48 hr after administration of the dye.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

In vitro assessment of vancomycin HCl compatibility after coinfusion with a specialized amino acid formulation.

Vancomycin usage at British Columbia's Children's Hospital has increased substantially in the Special Care Nursery as a consequence of a study demonstrating a reduced morbidity and mortality in neonates with necrotizing enterocolitis when treated with vancomycin and cefotaxime. The inability to place more than one peripheral intravenous access necessitates interruption of parenteral nutrition to infuse vancomycin, resulting in a reduction of the planned daily intake of these neonates. This is clinically significant with the administration of vancomycin because of the long administration period required for this drug (60 minutes). This study was designed to assess the physical and chemical stability of vancomycin with a standard neonatal parenteral nutrition solution, Vamin A, when coadministered through the same intravenous line. To simulate the actual clinical setting, the dose of vancomycin and the infusion rate of Vamin A were chosen to represent those commonly used in a 1-kg neonate. Physical compatibility was assessed using effluent obtained after coinfusion of vancomycin with parenteral nutrition solution. Duplicate samples were visually checked for color changes and precipitate. High-pressure liquid chromatography (HPLC) and pH testing were used to assess chemical compatibility of vancomycin. The results of physical compatibility revealed no color change or precipitate. No changes in pH were observed. HPLC determination confirmed that there were no significant time-dependent changes in vancomycin stability. The samples were studied over 24 hours to determine the rate of degradation of vancomycin, if any, under various temperature conditions. The concentrations were not significantly different from each other at the different temperatures studied. Thus, there was no apparent change in the concentration of vancomycin in the presence of Vamin A.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗