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Biomedical subjects

R B Jones

Publications and source records attributed to R B Jones.

At least 325 records · Page 18Linked to original sources
PubMed1982

Galactose intolerance and the risk of cataract.

Cataracts may arise in association with various major and minor disorders restricting galactose metabolism, and the risk is broadly associated with the degree of galactose intolerance. A family is described in which a girl presented at the age of 7 3/4 years with cataracts, galactosuria, and partial deficiencies of the enzymes galactokinase and galactose-1-phosphate uridyl transferase. Galactose intolerance as determined by an oral test was impaired and fluctuated with variation in activity of the above galactose enzymes. Minor defects were also present in the parents and a maternal half-brother. The child has a compound disorder of galactose metabolism differing from those previously described. Assessment of galactose tolerance may be useful in the investigation of families with an incidence of cataract.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1982

Prophylactic netilmicin in surgery.

Seventy-seven elective or emergency surgical patients were treated with a prophylactic course of netilmicin. Netilmicin (150 mg intramuscularly) was given 1 hour prior to operation and continued 12 hourly until the patient was free of risk of post-operative infection. There was no microbiological or clinical evidence of post-operative infection in general surgical or orthopaedic patients. Netilmicin seems to be less nephrotoxic than other aminoglycosides. Netilmicin serum levels were within expected values. Netilmicin was found to be an effective and well-tolerated antibiotic, and prophylactic treatment shortened the mean patient bed-stay and hence costs incurred.

Adult↗
PubMed1981

Natural history of malignant lymphomas with divergent histologies at staging evaluation.

The pathology and medical records of 515 patients with malignant lymphomas treated at the National Cancer Institute have been reviewed to determine the frequency and natural history of patients who have different histologic diagnoses in various tissue sites at their initial staging evaluation. Of the 101 patients who had multiple tissue sites biopsied, 33 patients had different histologic diagnoses. Eighteen patients had a nodular pattern in one site and a diffuse pattern in another. The final stage and treatment of these 18 patients were similar to that of the 27 patients with multiple identical nodular biopsies and 41 patients with multiple identical diffuse biopsies. However, the 56% complete response rate for patients with both a nodular pattern and a diffuse pattern was intermediate between that achieved in patients with identical nodular biopsies (70%) and identical diffuse biopsies (30%). Median survival for these three groups was as follows: identical nodular biopsies, 53 months; both a nodular and a diffuse pattern, 37 months; and identical diffuse biopsies, 12 months. These results demonstrate that patients with different histologic diagnoses in various sites at staging evaluation are not uncommon and have a unique natural history that should be considered in planning treatment.

Biopsy↗
PubMed1981

The effects of alterations in the external sodium concentration on human leucocyte sodium and potassium transport in vitro.

Human leucocytes incubated in tissue culture fluid of low-sodium concentration (2 mM; iso-osmolarity maintained with choline chloride) reached a new equilibrium within 1 hour and lost approximately 25% of intracellular potassium and 70% of intracellular sodium. The rate constant for ouabain-sensitive sodium efflux fell by more than 50% and the ouabain-insensitive rate constant increased nearly threefold in the low-sodium medium. Total sodium efflux fell in proportion to internal sodium whereas ouabain-insensitive sodium efflux remained unchanged. A reduction in external sodium from 140 to 2 mM was associated with a 75% fall in sodium influx. In the low-sodium medium ouabain-sensitive potassium influx exceeded ouabain-sensitive sodium efflux and no ouabain-sensitive potassium efflux could be demonstrated. Ouabain-insensitive potassium influx and that portion of potassium efflux which is dependent on external potassium fell in parallel in low-sodium cells, suggesting reduced activity of a ouabain-insensitive K:K exchange system.

Biological Transport↗
PubMed1981

The relationship between leucocyte and muscle zinc in health and disease.

1. A significant correlation between leucocyte and muscle zinc contents was observed in control patients and in patients with generalized diseases. 2. As muscle contains a large proportion of the whole-body zinc, it is suggested that leucocyte zinc content may be a useful indicator of tissue zinc status.

Humans↗
PubMed1981

Effect of extracellular potassium on the transport of sodium and potassium in rat thymocytes.

1. The effect of extracellular potassium on the transport of sodium and potassium in rat thymocytes has been studied in vitro. 2. A significant increase in the rate constant for total and ouabain-sensitive sodium efflux was demonstrated at an extracellular potassium concentration of 1 mmol/l as compared with that at either 0 or 2 mmol/l. 3. At potassium concentrations below 3 mmol/l ouabain-sensitive sodium influx was observed suggesting sodium-sodium exchange catalysed by the sodium pump. 4. Both total and ouabain-insensitive potassium efflux rose with external potassium. A small ouabain-sensitive potassium efflux was observed at all levels of external potassium studied. 5. Total and ouabain-insensitive potassium influx increased with external potassium, but did not appear to saturate. Ouabain-sensitive potassium influx reached a maximum at an external potassium concentration of 2 mmol/l then decreased with increasing external potassium.

Animals↗
PubMed1981

Increased sodium content and altered sodium transport in thymocytes of spontaneously hypertensive rats.

1. The intracellular sodium content and the sodium efflux rate constant have been determined in vitro in thymocytes derived from the Okamato-Aoki strain of spontaneously hypertensive rats. 2. A strong positive correlation between the systolic blood pressure and the sodium content of thymocytes was observed (r = 0.59, n = 39, P less than 0.001). 3. The rate constant for total sodium efflux was negatively correlated with systolic blood pressure (r = -0.43, n = 45, P less than 0.005) and this was due to a fall in the ouabain-sensitive component of sodium efflux. 4. Sodium efflux, influx and the thymocyte potassium content were not related to the blood pressure.

Animals↗
PubMed1981

Sympathetic modulation of mechanoreceptor sensitivity in frog skin.

1. Sympathetic effects on the mechanical sensitivity of frog cutaneous mechanoreceptors were examined in vivo. 2. Functionally identified units were tested with repetitive mechanical stimuli of threshold intensity during electrical stimulation of the sympathetic trunk. 3. Sympathetic activity resulted in increased sensitivity for three classes of afferents; slowly adapting compression receptors, slowly adapting stroke receptors, and rapidly adapting stroke receptors. Decreased sensitivity was produced in the fourth class, rapidly adapting compression receptors. 4. Preliminary tets of several possible modes of sympathetic influence indicated that blood flow changes, changes in probe-skin coupling and changes in tissue compliance could not account for the observed changes in receptor sensitivity. Na+ and Cl- ions, secreted by cutaneous mucous glands were found to be possible contributors to the decreased sensitivity of rapidly adapting compression receptors. Direct neurotransmitter action on the receptors, a likely mechanism of sympathetic action, was not tested. 5. The data indicate that systematic changes in cutaneous sensibility occur with modest changes in sympathetic efferent activity. Possible mechanisms of these sympathetic effects are discussed.

Action Potentials↗
PubMed1981

Microsomal dechlorination of chloroethanes: structure-reactivity relationships.

1. The dechlorination rates of six haloethanes were investigated in vitro, using liver microsomes derived from rats treated with Aroclor 1254. 2. The compounds studied were 1,1-dichloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2,2-tetrachloroethane, 1,1,1-trifluoro-2-chloroethane and hexachloroethane. 3. Dechlorination kinetics (Km and Vmax) were measured at various substrate concentrations. 4. Electron densities in the molecules for which dechlorination data are available were calculated by the MINDO/3 method. 5. A previously reported correlation between electronic parameters and dechlorination rate was not confirmed, but rather a separate relationship between these parameters for each of three structural classes (RCH2Cl, RCHCl2 and RCCl3) was observed. 6. On the basis of these observations, possible reaction mechanisms and their toxicological implications are discussed.

Animals↗
PubMed1981

The effect of antihypertensive therapy on abnormal leucocyte sodium transport in essential hypertension.

Sodium transport in leucocytes of essential hypertensives was studied in physiological media. Untreated hypertensives have depressed values for the total and ouabain-sensitive sodium efflux rate constant. Treatment with diuretics abolished this abnormality. These results are compatible with the presence of a circulating inhibitor of sodium transport in essential hypertension.

Adrenergic beta-Antagonists↗
PubMed1981

High-volume intraperitoneal chemotherapy with methotrexate in patients with cancer.

The use of high-volume i.p. chemotherapy with methotrexate (7.5 to 50 microM methotrexate administered via peritoneal dialysis technique) was studied in four patients with ovarian cancer and one patient with malignant melanoma. All had tumor localized to the peritoneal cavity or liver. Methotrexate concentration in the peritoneum could be maintained 18- to 36-fold higher than corresponding plasma concentrations using this method, plasma levels remaining in the range of 0.2 to 3 microM. While local toxicity was generally limited and manageable, mild aseptic peritoneal irritation was commonly seen, and one episode of bacterial peritonitis did occur. Because of the concentration difference between peritoneum and the systemic circulation, systemic toxicity was moderate with only six of 29 treatment cycles resulting in myelosuppression. No definite therapeutic benefit was seen, but the tumors of four of five patients had demonstrated resistance to a methotrexate-containing chemotherapeutic regimen prior to this study. Further investigation of this novel treatment modality is warranted. In addition, this study provides the first measurement of peritoneal methotrexate clearance and the ratio of peritoneal in total body clearance.

Adenocarcinoma↗