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Biomedical subjects

J L Barron

Publications and source records attributed to J L Barron.

At least 19 recordsLinked to original sources
PubMed1992

Increased urine neopterin levels in psoriasis.

The production of neopterin closely reflects activation of T-lymphocyte-mediated immunity. Oxidized and reduced forms of urine neopterin were measured by reversed-phase ion-pair high-performance liquid chromatography in patients with moderate to severe chronic plaque psoriasis (n = 40), and in a heterogeneous group of patients (n = 14) with cutaneous T-cell malignancies (CTCM). Results were compared with healthy non-psoriatic control subjects (n = 30). Neopterin levels were repeated after a course of ultraviolet B therapy (UVB) plus topical tar or dithranol, or photochemotherapy (PUVA), in 12 psoriatic patients. Fully oxidized urine neopterin levels and neopterin/creatinine ratios were significantly elevated in the psoriatic group compared with controls (P < 0.002, P < 0.05) but not in the CTCM group. Both neopterin and its creatinine ratio were significantly reduced by treatment (P < 0.05, P < 0.01). Psoriasis area and severity index scores (PASI) correlated strongly with urine neopterin levels (P < 0.001). These findings indicate that urine neopterin concentrations may be a marker of psoriatic disease activity, and further support the importance of activated T lymphocytes in the pathogenesis of psoriasis.

Adolescent↗
PubMed1992

Parathyroid hormone related protein in hypercalcaemia of Hodgkin's disease.

The role of parathyroid hormone related protein (PTHRP) as a humoral mediator of hypercalcaemia was investigated in a patient with lymphocyte depleted Hodgkin's disease during an episode of hypercalcaemia, using an immunohistochemical staining technique for PTHRP on the tumour tissue and an immunoradiometric (IRMA) assay for PTHRP1-86 on the patient's plasma. The plasma PTHRP was less than 0.23 pmol/l in the range found in normocalcaemic controls, and the immunohistochemical staining was not positive for protein. PTHRP did not have a role in the pathogenesis of hypercalcaemia in this patient.

Aged↗
PubMed1992

Carbamylated haemoglobin in normal, diabetic and uraemic patients.

Carbamylated haemoglobin arises from the non-enzymic modification of haemoglobin monomers by isocyanate derived from the spontaneous dissociation of urea. We measured carbamylated haemoglobin by high performance liquid chromatography in healthy subjects, non-uraemic hospital patients, diabetics, and different groups of uraemic patients. Carbamylated haemoglobin levels were found to be raised in uraemic subjects, but were independent of age, sex, glycaemic state and haemodialysis procedure. There was no significant difference in carbamylated haemoglobin levels between two groups of patients having different modes of dialysis treatment, probably indicating a similar degree of uraemic exposure in these patients.

Adult↗
PubMed1991

Effect of naltrexone upon self-injurious behavior, learning and activity: a case study.

Naltrexone significantly attenuated self-injurious behavior in a 20-year-old mildly retarded autistic male patient. The patient was videotaped daily and behavior was evaluated with a time-sampling procedure. Behavioral ratings of SIB frequency, SIB severity, and activity were collected automatically with a computerized system. Learning and memory were tested on a weekly basis with a modification of a paired associate learning test (PALT). Treatment with naltrexone resulted in (a) attenuation of SIB in the unstructured setting and (b) improvements in learning and memory without influencing activity levels.

Adult↗
PubMed1991

Carbamylated haemoglobin, urea kinetic modelling and adequacy of dialysis in haemodialysis patients.

Urea kinetic modelling (UKM) has increasingly been used for assessing adequacy of dialysis and protein nutritional status of dialysis patients. Using a precise HPLC method we developed, we measured carbamylated haemoglobin (CarHb) values in 20 stable twice-weekly dialysed patients and attempted to correlate their CarHb values with their UKM-derived indices. Based on these indices, 11 patients were found to have been adequately dialysed with sufficient protein intake, three patients were adequately dialysed but malnourished and six patients were under-dialysed. Estimated dietary protein intake correlated poorly with calculated daily protein catabolic rate in our patients. CarHb values were found to correlate strongly with the time-averaged urea concentrations, suggesting that CarHb might be a time-integrated urea-derived index. Those adequately dialysed patients have a mean (SD) CarHb value of 142 (29) micrograms CV/gHb against the underdialysed patients, 197 (30) micrograms CV/gHb (t-test, P = 0.002). We suggest that a CarHb value less than 175 micrograms CV/gHb may represent satisfactory uraemic exposure, whereas CarHb value greater than 175 micrograms CV/gHb is undesirable.

Adult↗
PubMed1990

Failure of thiazide diuretics to increase plasma calcium in mild primary hyperparathyroidism.

Thirteen patients with mild primary hyperparathyroidism who were taking thiazide diuretics intermittently for periods of up to 18 months were followed up for a mean of 5.3 years. No significant difference was found in either plasma total calcium corrected for albumin or whole blood ionized calcium in these patients between the periods on or off thiazides. We conclude that thiazide diuretics are not contraindicated in such patients.

Adult↗
PubMed1990

Plasma B-endorphin levels in patients with self-injurious behavior and stereotypy.

B-endorphin and cortisol concentrations were examined in the plasma of mentally retarded patients who displayed symptoms of self-injurious behavior (SIB) (n = 9), stereotypy (n = 17), or SIB plus stereotypy (n = 14). Morning and evening samples were compared with a matched patient control group (n = 13) and a group of nonretarded controls (n = 17). Compared with nonretarded controls, the retarded control group had significantly lower b-endorphin concentrations for the morning sample and nonsignificantly lower concentrations for the evening sample. The combined patient groups had lower b-endorphin levels than did nonretarded controls for both samples. Patients with SIB and stereotypy had significantly higher morning levels of b-endorphin than the retarded controls. The evening levels of the SIB plus stereotypy group also were higher than retarded controls but were not significant. Levels in the SIB and stereotypy group were slightly elevated compared with retarded controls. Cortisol levels were identical for all groups. B-endorphin and cortisol significantly covaried for the nonretarded controls but not the patients. Results indicated that compared to a matched control group, patients with SIB plus stereotypy have elevated b-endorphin plasma.

Adult↗
PubMed1990

An orally administered opiate blocker, naltrexone, attenuates self-injurious behavior.

Several recent reports have indicated that opioid blockers are effective in attenuating self-injurious behavior (SIB). In the present study, four patients with SIB were challenged with four fixed doses (0, 25, 50, 100 mg) of naltrexone. In a double-blind procedure, all patients received each dose on a different week as determined by latin square design. Naltrexone was given on Monday and Wednesday of each week, and patients were videotaped daily for 10 minutes in the morning and afternoon. The tapes were scored for incidents of SIB, stereotypy, and activity, with interrater reliability of 0.93. The Conners Teacher Rating Scale was administered by staff in the morning and afternoon each day. The Vineland was completed each week (Thursday). All patients had decreased SIB when treated with naltrexone. Three patients decreased their SIB as dose of naltrexone increased. There were no consistent effects of naltrexone on stereotypy, activity, or performance on the Conners or the Vineland. These results suggest that endogenous opioids are implicated in SIB and that naltrexone is a powerful tool for examination of this treatment-resistant behavior.

Adult↗
PubMed1990

Determination of carbamylated hemoglobin by high-performance liquid chromatography.

We have developed an HPLC method for measuring carbamylated hemoglobin (CarHb), based on the quantification of valine hydantoin formed from the released NH2-terminal carbamyl valine residue after acid hydrolysis of hemoglobin. In uremia, CarHb is produced by nonenzymatic post-translational modification of the terminal amino group of hemoglobin monomers by isocyanic acid, derived from the spontaneous dissociation of urea. We measured CarHb in 25 nonuremic control subjects, 24 nonuremic diabetic subjects, and 30 patients with stable chronic renal failure. There was no significant difference between the controls and diabetic patients, their mean (SD) CarHb values being 41 (11.5) and 38 (10.8) micrograms of carbamyl valine per gram of hemoglobin (microgram CV/gHb), respectively. Mean (SD) CarHb values in the uremic patients were much greater, 164 (87.7) microgram CV/gHb. There was significant correlation between the concentrations of CarHb and plasma urea in the uremic subjects. Thus CarHb provides a urea-derived index of chronic uremia.

Buffers↗
PubMed1988

Pancreatic somatostatinoma: presentation with recurrent episodes of severe hyperglycaemia and ketoacidosis.

A 47-year-old woman was admitted on four occasions over a four-year period with severe hyperglycaemia associated with marked ketoacidosis. She had weight loss with hepatomegaly and ultrasonography indicated a pancreatic tumour which was shown to be a somatostatinoma. Resection resulted in prolonged survival. The biochemical and morphological features of this rare tumour are presented, and an explanation for the unusual presentation of a somatostatinoma with episodes of ketoacidosis is given.

Adenoma, Islet Cell↗
PubMed1987

Comparison of serum calcium fractions during haemodialysis and peritoneal dialysis.

Total, ultrafiltrable and ionised calcium concentrations were determined in anaerobic serum from healthy volunteers, patients immediately before and after haemodialysis and patients on continuous ambulatory peritoneal dialysis (CAPD). Protein-bound, complexed and albumin-corrected total calcium concentrations were calculated from the results. During haemodialysis, complexed calcium did not change, whereas the other fractions increased. For patients on CAPD, the total, ionised and protein-bound calcium results were frequently lower than the reference group, whereas the ultrafiltrable and albumin-corrected total calcium results were within or higher than the reference group. Albumin-corrected total calcium for all subjects correlated better with ultrafiltrable calcium than with ionised calcium. It was concluded that low ionised calcium concentrations found in CAPD patients may be related to low albumin concentrations, and the concentration of physiologically active calcium may be normal in these patients.

Adult↗