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Biomedical subjects

C C McCormick

Publications and source records attributed to C C McCormick.

52 records · Page 3Linked to original sources
PubMed1981

Post-traumatic syringomyelia (cystic myelopathy).

With careful long-term follow up of patients presenting with paraplegia at the thoraco-lumbar level it will be noted that a small group of patients emerge, constituting between one and two per cent, who will subsequently develop neurological defects at a higher level in the spinal cord. The development of cystic cavitation within the spinal cord above the level of the injury, i.e. post-traumatic syringomyelia is noted. Careful examination of the upper limbs in follow up management and investigation by metrizamide myelography is described.

Adult↗
PubMed1981

Regulation of intestinal metallothionein biosynthesis in rats by dietary zinc.

Response of intestinal metallothionein and zinc to dietary zinc intake was investigated in zinc-depleted rats, after a single feeding by stomach tube of a purified diet supplemented with either 125 ppm zinc or less than 1 ppm zinc. Serum zinc concentration was maximal 3 hours post-feeding, then stabilized at lower levels returning to baseline concentration by 18 hours. Mucosal zinc concentration rose to a maximum by 6 hours after feeding and plateaued at slightly lower levels thereafter, due to association of this zinc with metallothionein. The rate of metallothionein synthesis rose 4-fold, 6-9 hours after feeding, coinciding with the maximal contest of translatable metallothionein mRNA concentration. Together, these findings provide strong evidence for a regulatory role of metallothionein in zinc absorption and homeostasis, where dietary zinc influences subcellular events in mucosa affecting regulation of the metallothionein gene. These events include the induction of de novo metallothionein synthesis, preceded by an increase in translatable mRNA specific for this metalloprotein, and followed by a reduction in zinc absorption simultaneous with the binding of absorbed zinc with newly synthesized thionein polypeptides.

Animals↗
PubMed1981

Myelography with metrizamide--an analysis of the complications encountered in cervical, thoracic and lumbar myelography.

Detailed analysis of complications in 363 patients undergoing myelography with metrizamide is presented. Patients have been separated into three groups: those who had lumbar myelograms via lumbar puncture; patients who had cervical myelograms via lumbar route and patients who had cervical myelograms via cervical puncture (lateral C1/C2. approach). Analysis has revealed that the incidence of minor complications like headaches, nausea, and vomiting is higher than that associated with myodil myelography. Nevertheless, it is concluded that because of lack of long term disability of arachnoiditis, and because of greater diagnostic accuracy, metrizamide represents the best contrast medium for myelography currently available.

Adolescent↗
PubMed1981

Induction of hepatic metallothionein by feeding zinc to rats of depleted zinc status.

Induction of hepatic metallothionein was investigated in zinc-depleted rats after a single feeding (via stomach tube) of a complete diet with or without supplemental zinc. Subsequent to a maximum elevation in serum zinc (3.25 micrograms/ml) at 3 h, the rate of metallothionein synthesis increased 4.5-fold by 10 h after feeding. Changes in the rate of metallothionein synthesis coincided with similar changes in the level of translatable mRNA coding for metallothionein. Accumulation in liver of Zn2+ as metallothionein rose to a maximum by 12 h after diet administration and thereafter remained constant. Radioactive zinc (65Zn) included in the diet rapidly associated with newly formed metallothionein. Unlike Zn2+, 65Zn exhibited marked fluctuations within the 24-h period following feeding, indicating that zinc associated with metallothionein may be capable of exchange and/or dissociation. Changes in total liver 65Zn were accompanied by concomitant changes in metallothionein-bound 65Zn. This study has related (temporally) the metabolism of dietary zinc to the induction, apparently via transcription of mRNA, of hepatic metallothionein.

Animals↗
PubMed1981

Interrelationships between environmental temperature and nutritional status of chicks.

The interrelationship between nutritional status and resistance to acute heat stress has been studied in chicks. Fasting up to 72 hours progressively increases survival time. Chicks that had been consuming a diet in which all nonprotein calories were supplied as triglycerides as compared to glucose survive longer in both nonfasted and 48-hour fasted states. Phosphorus deficiency reduces survival time of 24- or 48-hour fasted chicks but not nonfasted chicks. A calcium deficiency enhances survival time of 24-hour fasted chicks subjected to heat stress but a calcium excess progressively reduces survival time. The chick may serve as a model to study the relationship of nutritional status to acute heat stress.

Acidosis↗
PubMed1980

Phosphorus nutrition and fasting: interrelated factors which affect the survival of young chickens exposed to high ambient temperature.

The interaction of phosphorus nutrition and fasting on the tolerance of young chickens acutely exposed to high temperature was studied. We also investigated a possible relationship between plasma phosphate (Pi) and body temperature (Tr) of chicks during heat exposure. Survival time (ST) of 24-hour fasted (F-24) chicks previously fed a low-phosphorus diet (LP) was markedly lower than ST of F-24 chicks fed an adequate phosphorus diet (AP). Diet, however, had no effect on ST of chicks fasted 12 hours (F-12). The apparent metabolic responses of F-24 chicks were qualitatively different than those of F-12 chicks suggesting that the effect of previous phosphorus nutrition was dependent on metabolic status of chicks before heat exposure. The concentration of Pi during heat exposure of F-24 chicks fed the experimental diets was highly (P less than 0.001) correlated with Tr. At heat-induced exhaustion, Tr of chicks fed either diet was not different. Pi of these groups at this point was nearly identical despite marked differences in the time at which this event occurred. An investigation concerning a possible relationship between Pi and the respiratory failure known to occur in hyperthermic chickens, revealed that respiratory muscular fatigue is not the primal cause of respiratory failure. Our results demonstrated that phosphorus nutrition, Pi and metabolic status are dependent factors related to the tolerance of young chickens exposed to high temperature.

Animals↗
PubMed1980

Effect of calcium deficiency on survival time of young chickens acutely exposed to high temperature.

A study concerning the effect of calcium and phosphorus nutrition on the tolerance of young chickens acutely exposed to high temperature was conducted. Fasted (24 hours) chicks previously fed a low-phosphorus (LP), adequate-calcium (AC) diet exhibited reduced survival time (ST) to heat exposure when compared to chicks fed an adequate-phosphorus (AP) and AC diet. Survival time increased markedly as a result of feeding low dietary calcium. In chicks fed low-calcium diets, the level of dietary phosphorus did not influence heat tolerance. An additional experiment showed that ST of fasted chicks was inversely proportional to the level of dietary calcium fed. With respect to nonfasted chicks, diet had no effect on ST to heat exposure despite differences in plasma phosphate (Pi) and calcium (Ca). Plasma phosphate and Ca of fasted chicks were, on the other hand, not indicative of previous diet. The concentration of Ca and Pi of chicks prior to fasting was highly correlated (P less than 0.001) with subsequent heat tolerance. We suggested that the effects of diet on ST of fasted chicks may be related to nutritional alterations in Ca and Pi prior to fasting. Heat-induced changes in Ca and Pi were not related consistently to the occurrence of heat exhaustion. This suggested that changes in Ca and Pi may not be associated with heat tolerance. We concluded that previous calcium and phosphorus nutrition were dependent factors which influence markedly the survival of fasted chickens acutely exposed to high temperature.

Animals↗
PubMed1979

Fasting and diet affect the tolerance of young chickens exposed to acute heat stress.

The interaction of nutritional status on the tolerance of young chicks to acute heat stress (HS) was investigated. The results of experiment 1 demonstrated that fasting for 24, 48 or 72 hours progressively increased survival time (ST) of chicks exposed to HS. When compared to that of non-fasted (NF) chicks ST more than doubled for 48 and 72 hour fasted chicks. During HS plasma glucose increased in fasted chicks but decreased in NF chicks. Conversely, plasma free fatty acids decreased in fasted chicks and increased in NF chicks. Plasma phosphate of all chicks fell markedly as a result of HS. Chicks of experiment 2 were fed a "carbohydrate-free" diet (CF). Survival time of NF chicks fed CF was significantly greater than that of NF chicks fed a diet containing glucose. The apparent metabolic responses of NF chicks fed CF corresponded to those of fasted chicks of experiment 1. It was suggested that the metabolic substrate utilized by chicks during HS influences ST. The effect of CF diet on ST was also observed in chicks which were fasted for 48 hours prior to HS. Plasma phosphate of chicks exhibiting fasting metabolic responses was not significantly different at heat induced prostration despite marked differences in ST. The results of experiment 3 demonstrated that ST of fasted (24 hour) chicks previously fed a low phosphorus diet was markedly lower than compared to that of fasted chicks fed adequate dietary phosphorus. The effect of diet was found to be dependent on metabolic status since level of dietary phosphorus fed had no effect on ST of NF chicks. The results of the present study indicated that metabolic and nutritional status affect the tolerance of young chicks acutely exposed to high ambient temperature.

Animals↗