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Biomedical subjects

J G Rose

Publications and source records attributed to J G Rose.

36 records · Page 2Linked to original sources
PubMed1977

Rates of glucose utilization and glucogenesis in rats in the basal state induced by halothane anaesthesia.

1. Rates and rate coefficients of glucose utilization and replacement were determined with [5-3H]- and [U-14C]-glucose in rats starved for 24h, either conscious or under halothane anaesthesia, in a thermoneutral environment. Plasma insulin concentrations were also measured. 2. Halothane anaesthesia decreased the turnover rate by 20%, which was similar to previously reported decreases in metabolic rates caused by natural sleep. 3. Fractional recycling of glucose carbon was little affected by halothane. 4. Comparison of values in one rat with those in another, among both conscious rats and those under halothane anaesthesia, showed that rate coefficients were inversely correlated with plasma glucose concentrations. 5. These findings indicated that halothane, in the concentration used (1.25%, v/v), had little specific effect on glucose metabolism. 6. Although equilibrium plasma glucose concentrations in different rats under halothane were widely different (4-8 mmol/l) the rates of utilization were very similar (2.5-3.1 micronmol/min per 100 g), indicating that these rates were determined by the production of glucose from gluconeogenic precursors released by basal metabolism, the rate of which is necessarily similar in different rats. 7. Among rats under halothane anaesthesia plasma insulin concentrations were negatively correlated with rate coefficients, showing that the differences between rate coefficients were mostly accounted for by differences between rats in tissue sensitivities to insulin. Thus in each 24h-starved rat, sleeping or resting, the main regulators of the plasma glucose concentrations were the rate of supply of gluconeogenic substrates from energy metabolism and the intrinsic sensitivity of the tissues to insulin. 8. We found that a commonly used deionization method of purifying glucose for determination of its specific radioactivity was inadequate.

Anesthesia, Inhalation↗
PubMed1977

Glucose turnover in the post-absorptive rat and the effects of halothane anaesthesia.

1. Rates and rate coefficients of glucose utilization and replacement in post-absorptive rats, either conscious or under halothane anaesthesia, were determined in a thermoneutral environment by using [5-3H]- and [U-14C]glucose. Label was not injected into rats under halothane until about 0.5h after anaesthesia was initiated. 2. Comparison with the results for 24h-starved rats in the preceding paper [Heath et al. (1977) Biochem. J. 162, 643-651] showed that insulin concentrations were considerably higher but rate coefficients for glucose utilization were little altered in post-absorptive rats. Sensitivity to insulin was thus considerably increased by a 24h period of starvation in the rat. 3. Fractional recycling of glucose carbon in post-absorptive rats was under one-half of that in starved rats, reflecting the larger contribution of liver glycogenolysis to glucose production in the former. 4. In post-absorptive rats halothane decreased the mean rate of glucose utilization by about 17%. This decrease was associated with an increase in mean plasma insulin concentration, showing that halothane decreased sensitivity to insulin. 5. Recycling was slightly increased by halothane, indicating that the contribution of liver glycogen to the total glucogenic rate was decreased, probably because liver glycogen concentration were about 40% lower throughout the rate determinations in halothane. 6. Comparison of our results with earlier work shows that during and shortly after induction of halothane anaesthesia glucose turnover must have been greatly increased whereas from about 0.5h after induction it was decreased.

Anesthesia, Inhalation↗
PubMed1975

The recovery of function of chronically obstructed and infected ureters.

Twelve experiments in which intraluminal ureteral pressure, ureteral diameter, aortic blood pressure, and respirations were measured, and in which ureteral wall tension was calculated, were performed on 11 female dogs. These experiments demonstrated that the impairment in ureteral function caused by chronic obstruction and infection could be reversed after surgical correction of the obstruction in conjunction with antibiotic therapy.

Animals↗
PubMed1971

The effects of the stress caused by experimental procedures on alanine, aspartate, glutamate and glutamine in rat liver.

Rats were stressed by intravenous injection, tail-warming or moderate restraint for 30s, i.e. by stresses imposed by normal handling during experiment. Liver glutamate concentrations were greatly affected. The results were substantially the same in two varieties of rat (Wistar and Sprague-Dawley), in two laboratories, in experiments carried out by two sets of workers, and after all three stresses. The following detailed results refer to Wistar rats. 1. In starved rats at 20 degrees C and 30 degrees C and in post-absorptive rats at 20 degrees C stress by injection raised liver glutamate concentrations from 1.54, 1.57 and 1.88mumol/g wet wt. 30s after injection to 3.4, 2.7 and 3.6mumol/g wet wt. respectively a few minutes later. In starved rats at 20 degrees C the concentration then fell slowly to 2.3mumol/g wet wt., in starved rats at 30 degrees C it remained steady, and in post-absorptive rats at 20 degrees C it rose slowly to about 4.3mumol/g wet wt. The final values seemed fairly steady and corresponded to an ;alert' state. 2. In starved rats at 20 degrees C anaesthesia, with or without injection or cannulation during it, raised glutamate concentrations to the ;alert' values, which were maintained for 2-3h. 3. Liver alanine concentration in post-absorptive rats initially fell from 1.5 to 0.8mumol/g, and then stayed fairly constant. 4. Aspartate and glutamine concentrations altered only in starved rats, and proportionately much less than those of glutamate. 5. The necessity for knowing the time-dependence of glutamate concentrations after experimental handling is emphasized. 6. There is no wholly satisfactory explanation of the observations.

Alanine↗
PubMed1969

The distribution of glucose and [14C]glucose between erythrocytes and plasma in the rat.

1. Of the glucose in rat blood 79.8+/-3.3% (s.d.) was in the plasma. The variance was mostly due to differences between rats. 2. The concentration of glucose in erythrocyte water was 51+/-8% (s.d.) of that in plasma water. 3. The ratio (specific radioactivity in plasma)/(specific radioactivity in whole blood), i.e. the P/B ratio, was estimated for glucose at intervals after intravenous injection of [U-(14)C]glucose and [U-(14)C]fructose. The ratio differed from unity by more than the standard error of a single determination of the specific radioactivity of blood or plasma glucose except from 10 to 17min. after injection of [(14)C]glucose and from 22 to 30min. after injection of [(14)C]fructose. At all other times specific radioactivities in blood had to be corrected to give specific radioactivities in plasma. How to do so is described. 4. The P/B ratios were accounted for by a turnover of glucose in erythrocytes of 0.14mumole/min./ml. of erythrocytes. 5. Metabolism of glucose in rat erythrocytes is unlikely to be a major source of lactate.

Animals↗
PubMedDate not supplied

Nuclear medicine in diagnosis and treatment of diseases of the head and neck. I. Salivary and parathyroid gland disease and one identification and staging of head and neck tumors.

The advent of both improved imaging systems and new radioactive agents has increased the effectiveness of nuclear medicine in diagnosing and treating diseases of the head and neck. In this first in a series of two articles, the role of nuclear medicine is discussed in the evaluation of diseases of the salivary and parathyroid glands, and in the identification and staging of head and neck tumors. Radionuclide studies of the salivary glands are useful in the identification of tumors and the evaluation of gland function. Such studies are a valuable adjunct in the diagnosis of Sjögren's syndrome and of acute and chronic inflammatory disease. Radionuclide imaging also has been helpful in the detection of adenomata and hyperplasia of the parathyroid glands and often complements ultrasonography localization procedures. The advent of gallium-67 imaging has improved the staging of head and neck tumors.

Gallium Radioisotopes↗
PubMedDate not supplied

Nuclear medicine in diagnosis and treatment of diseases of the head and neck: II.

The advent of both improved imaging systems and new radioactive agents has increased the effectiveness of nuclear medicine in diagnosing and treating diseases of the head and neck. In this second of two articles, we discuss radionuclide bone imaging and the role of nuclear medicine in the management of thyroid disease. Radionuclide bone imaging is useful in the differential diagnosis of sinusitis, the early detection of head and neck fracture, the assessment of temporomandibular joint disease, and the identification of local extension of primary head and neck carcinoma. In the management of thyroid disease, radionuclide technology is uniquely helpful in the diagnostic evaluation of the thyroid nodule and radioactive iodine continues to play a major role in thyroid cancer therapy.

Bone Diseases↗
PubMedDate not supplied

The effect of aging on the metabolic clearance rate and distribution of cortisol in man.

Previous studies of cortisol kinetics in old people have been flawed. All but one used a large dose of unlabelled cortisol, which will itself alter the kinetic parameters, and in none was metabolic clearance rate (MCR) calculated. We have, therefore, injected [(3)H]cortisol into men aged 20-38 and healthy (screened) men and women aged 63-83 years and followed its disappearance from the circulation for 3 h. In all three groups the disappearance curves corresponded closely to a double exponential, with half-lives of around 5 and 65 min. A two-pool model was assumed, one being purely a side-pool. The initial and total volumes of distribution and the MCR, but not the clearance rate for exchange between the two pools, tended to be lower in the elderly men than in the young; only the difference in total volume was significant. All these parameters were lower in the elderly women than in the elderly men. We conclude that any decline in cortisol MCR and related kinetic parameters with aging in men is small compared with variation from other sources. These parameters are lower in elderly women than men, in line with a reported sex difference in MCR in young subjects.

Journal Article↗
PubMedDate not supplied

Cortisol kinetics in elderly women with persistently high cortisol concentrations after proximal femur fracture.

OBJECTIVES: Elderly women with proximal femur fracture show abnormal persistence of increased cortisol concentrations, which could contribute to the high morbidity associated with this injury. Two weeks after injury, the authors found substantially increased urinary free cortisol excretion, which usually reflects the integrated concentration of free (bioactive) cortisol in plasma. However, there was a proportionally smaller increase in cortisol production rate. The authors have now tested the hypothesis that this was caused by a decreased metabolic clearance rate (MCR) rather than increased renal clearance, because the latter but not the former would invalidate free cortisol excretion as an index. SETTING: Orthopaedic wards in a teaching hospital. PATIENTS: Thirteen women aged seventy-one to ninety-two years who had sustained a proximal femur fracture approximately two weeks earlier were compared with ten healthy women aged sixty-seven to eighty-three years. These subjects are similar to those in the authors' previous study. MAIN OUTCOME MEASUREMENTS: The authors used single injections of [3H] cortisol to measure its MCR and estimated hepatic blood flow with indocyanine green. RESULTS: The patients with hip fractures had higher plasma cortisol concentrations than did the healthy subjects, as expected. Cortisol MCR was approximately 20 percent lower in the patients, and estimated hepatic blood flow was approximately 35 percent lower in the patients. Analysis of covariance showed that the difference in MCR was the result of the small difference in age between the groups rather than to injury per se. CONCLUSIONS: A lower cortisol MCR in the patients with hip fractures explains the authors' previous results and validates urinary free cortisol excretion as an index. The data suggest a roughly threefold mean increase in plasma cortisol bioactivity two weeks after hip fracture.

Aged↗