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Biomedical subjects

R McCormick

Publications and source records attributed to R McCormick.

8 recordsLinked to original sources

Systemic infusion versus bolus chemotherapy with 5-fluorouracil in measurable metastatic colorectal cancer.

From January 31, 1986 to January 31, 1989, 184 eligible patients were enrolled in a randomized study of either infusional or bolus 5-fluorouracil (5-FU) for the treatment of metastatic measurable colorectal cancer. Infusion was administered at an escalated dose schedule starting at 350 mg/m2 per day for 2 weeks with a 2-week rest period on a monthly basis, while bolus 5-FU was started at 400-450 mg/m2 for 5 days every 28 days. In these chemotherapy-naive patients with good performance status, the infusion arm produced a response in 11 of 88 patients versus 6 of 82 in the bolus arm (p = 0.384). Progression free survival was significantly longer (p = 0.0139) in the infusion group (3.8 versus 2.3 months), but no significant difference in survival was observed (p = 0.207). As expected, the toxicities of the regimens were different in character, but each had approximately a 20% incidence of significant toxicities. Neither of these methods of administering fluorouracil results in an exceptional response rate, nor does the infusion have an impact on survival as compared to the bolus route. If this type of complicated infusional approach is to continue, especially with increasing dosage (which could be accomplished on our schedule), randomized studies with survival as an endpoint must remain the gold standard.

Adult

Myofibrillar, mitochondrial and valvular morphological alterations in cardiac hypertrophy among copper-deficient rats.

Histological aspects of Cu-deficient hypertrophied rat hearts were evaluated to determine causal factors. Twenty-four male weanling rats were fed either Cu-adequate (8.0 mg/kg diet) or Cu-deficient (0.4 mg/kg diet) diets until 9 or 11 wk of age. Copper-deficient rats had increased mitochondrial:myofibrillar ratios compared with Cu-adequate rats. Mitochondria were vacuolated. Cristae seemed fragmented and matrix seemed translucent and they tended to distort the myofibrils. Glycogen granules and lipid droplets were more frequently observed in Cu-deficient rats. When the Cu-deficient rats were examined separately, the larger hearts in the older rats had smaller mitochondrial:myofibrillar ratios, but had larger myofibrillar volume densities. Valves from Cu-deficient rats had less connective tissue and seemed fragmented in areas. In 9-wk-old Cu-deficient rats, there was a negative correlation between heart: body weight ratios and bicuspid valve scores, whereas 11-wk-old rats demonstrated the same relationship for tricuspid valves with myofibril volume density. These results suggest that there are two components contributing to cardiac hypertrophy in copper deficient rats: 1) an enlarged mitochondrial area and 2) myofibrillar enlargement. Hematocrit values did not seem to be related to cardiac hypertrophy.

Animals

Electrical stimulation of the medial forebrain bundle-posterior lateral hypothalamus attenuates gastric lesions.

The major purpose of Experiment 1 was to see if electrical stimulation of the brain in an area that supports self-stimulation can act during stress to attenuate the severity of gastric lesions produced by six hours of tailshock and restraint. It was found that rats receiving electrical stimulation of the medial forebrain bundle-posterior lateral hypothalamus had significantly less gastric pathology than control subjects not receiving stimulation. Further experiments sought to examine characteristics of the stimulation that would account for this finding. Experiments 2 and 3 studied signal and analgesic properties, respectively, of the brain stimulation, but did not find evidence for their involvement in the effect.

Analgesia