Plasma concentrations and renal clearance of orotic acid in argininosuccinic acid synthetase deficiency

Argininosuccinic acid synthetase deficiency (ASD) is a rare disorder of urea cycle metabolism, with pronounced citrullinemia and orotic aciduria being characteristic biochemical features. To further investigate the role of plasma orotic acid and its possible use for monitoring the metabolic status in ASD, we determined plasma orotic acid, amino acid, and ammonium levels in plasma samples collected over a period of 3 years from a patient who is now 8 years of age. Orotic acid plasma concentrations varied widely from less than 1 μmol/l to more than 60 μmol/l. The renal clearance of orotic acid was eightfold the glomerular filtration rate, thus supporting an active mechanism underlying the excretion of this pyrimidine. Data obtained during a metabolic crisis yielded a statistically significant linear correlation of orotic acid plasma levels with those of glutamine and ammonium, which are generally accepted for assessment of the successful treatment of this disorder. Our data revealed no advantage of plasma orotic acid concentrations over the established amino acids (glutamine and arginine) and ammonium for determining acute treatment responses. Since several effects of high levels of orotic acid have been described in mammals, further research is necessary to assess a possible contribution of orotic acid to the pathogenesis of ASD and the use of plasma orotic acid levels in the long-term monitoring of these patients. Received: 3 November 1998 / Revised: 3 May 1999 / Accepted: 3 May 1999     

Measuring quality of life in secure care: comparison of mentally ill and personality disordered patients

Improving quality of life for patients is emerging as a legitimate goal for UK inpatient forensic mental health services. The Lancashire Quality of Life Profile (LQOLP), which has been used widely to measure well-being in community settings, was trialed on an inpatient population being cared for under conditions of high security. Two groups of male patients, drawn from within the same institution but with markedly different clinical conditions, i.e. schizophrenia (N = 47) and personality disorder (N = 48), were interviewed using the LQOLP. Although both groups had been cared for under largely similar environmental conditions over similar lengths of time (9.5 years), the subjective global well-being of the two groups differed systematically as did other objective and subjective well-being measures. However, analysis found that the variations in global well-being could not be attributed readily to factors covered by the interview, including either current mood or personality. Possible reasons for these findings and implications for the use of the LQOLP under conditions of high security are discussed.     

Standardization and potential use of HPLC for detection of cellular placental alkaline phosphatase using established tumour cell lines and fresh tumour biopsies

Placement alkaline phosphatase (PLAP) is one of the cellular phosphatases (ALP) expressed in patients with testis cancers, particularly in seminomas. Using various techniques including Western blot and high-performance liquid chromatography (HPLC) systems and ATC2, a newly developed specific anti-PLAP monoclonal antibody (Mab), the presence of active form of PLAP in lysates prepared from testis tumour fragment and tumour cell lines, was studied. This was carried out following isolation of PLAP from biological samples using CNBr Sepharose-conjugated ATC2 beads. The results showed that: (1) The target for the newly developed Mab ATC2 was PLAP. (2) The ATC2-conjugated bead system was an efficient method for isolating pure PLAP. (3) Diethylamine (DEA), in contrast to urea and glycine, was the most efficient for separation of PLAP from ATC2-conjugated beads, as the isolated molecule did not lose any phosphatase activity and there was very little uncoupling of the ATC2 Mab from the beads. (4) ATC2-conjugated CNBr beads could pick up PLAP from a solution containing standard PLAP and lysates prepared from tumour cell lines or testis tissue fragments positive for the PLAP. (5) HPLC profile of testis tumour lines and testis tumours showed two distinct peaks with ALP activity, one at retention time 7-8 min (corresponding to 95 kDa molecule) and one at 12-13 min corresponding to 70 kDa molecule). These data demonstrated the potential use of various biochemical methods in combination with HPLC for isolation of the fully functional molecules with ALP activity from different samples including lysates prepared from patients with testis cancer. The nature of ALP activity at 95 kDa is being investigated as no such molecule has been reported previously. These techniques might have an important implication for an early detection of germ cell tumours, particularly in patients with equivocal ultrasound.     

The 11th Meeting of the European Society for Paediatric Infectious Diseases (ESPID) 26–28 May 1993 Helsinki,Finland

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The 11th Meeting of the European Society for Paediatric Infectious Diseases (ESPID) 26–28 May 1993 Helsinki, Finland     

The effects of clofibrate on plasma glucose,lipoproteins, fibrinogen,and other biochemical and haematological variables in patients with mature onset diabetes mellitus

Summary We have studied the effects of clofibrate treatment on glucose tolerance and plasma insulin, plasma triglyceride, cholesterol and non-esterified fatty acid (NEFA) levels, and on various haematological variables (including plasma fibrinogen level, red cell flexibility, whole blood viscosity, and plasma -thromboglobulin level) in patients with mature-onset diabetes. Twenty-two patients (11 men and 11 women) were randomly allotted to treatment with clofibrate, 1 g twice daily, or a corn-oil placebo for 12 weeks, and then changed to the alternate medication for another 12 weeks. Half the patients took clofibrate in the first 12 weeks of the study, and half took the placebo. The patients stayed on their usual diet, and 13 also took tolbutamide before and during the trial. The trial was double-blind. At the beginning, middle and end of the trial fasting measurements were made, and plasma glucose, insulin, triglyceride, and NEFA concentrations were then measured repeatedly during the next 8 h (from 8.00 a. m. to 4 p. m.), to allow calculation of the mean 8-h concentration of these substances. In general, plasma concentrations of glucose, triglyceride, cholesterol, NEFA and fibrinogen were lower when the patients were taking clofibrate then when they were taking the corn-oil placebo, but higher when taking the placebo than at entry to the trial. We favour the explanation that clofibrate has lowered these concentrations, when compared with the placebo. The alternative interpretation, that 2 g per day of the placebo increases plasma concentrations of glucose, triglyceride, cholesterol, NEFA and fibrinogen, and that clofibrate has little effect, seems unlikely. The first interpretation, that clofibrate has a positive effect when compared with an inert placebo, has been adopted when interpreting the results. Clofibrate treatment led to a 15% lower fasting blood glucose level, and 11% lower mean 8-h glucose concentration than did placebo (p<0.01) but it did not significantly change plasma insulin concentration. The fasting and mean 8-hour concentrations of plasma triglyceride and fasting plasma cholesterol concentrations were reduced by clofibrate (by 44%, 33% and 10% respectively, p<0.05). Clofibrate decreased the fasting plasma NEFA level by 27% (p<0.01), and the mean 8-h plasma NEFA concentration by 23% (p<0.05). A weak relationship between the mean 8-h levels of plasma NEFA and plasma glucose (r=0.49, p<0.05) was consistent with the suggestion that the change in plasma glucose could, in part, be due to a change in NEFA concentration. The mean plasma fibrinogen concentration was decreased 23% by clofibrate (p<0.01). There was a positive correlation between the observed decrease during treatment and the baseline fibrinogen concentration (r=0.80, p<0.001), i. e. the greatest decrease occurred in those subjects with the highest plasma fibrinogen concentrations. Whole blood viscosity fell slightly, but erythrocyte flexibility was not significantly changed by clofibrate. The mean haemoglobin concentration and leucocyte count fell slightly during clofibrate treatment and the platelet count rose. -thromboglobulin was not affected. Clofibrate treatment was associated with rises in plasma albumin, urea, creatine kinase and aspartate aminotransferase, and falls in plasma bilirubin, -glutamyl-transpeptidase and alkaline phosphatase. Most of these changes occurred within the reference range.     

Regional loss of the y-chromosome in urothelial carcinoma

Specific chromosomal losses have been reported for various human tumors. We have now investigated ten cases of urothelial carcinoma and observed genomic alterations by a new method allowing detection of chromosomal losses directly in the tissue section. In 6 out of 8 male carcinomas, the Y-chromosome was lost either in single cells and isolated areas or in extended regions of the tumor sample. Presence of chromosome 1 served as an internal control. This new in situ method allows studies of chromosomal alterations in relation to their tumor topology and the observations constitute the first report on such localised tumor-specific genomic changes.     

Determination of glomerular size-selectivity in the normal rat with Ficoll.

Diffusion studies in vitro indicate that Ficoll behaves more like an ideal spherical molecule than does dextran, suggesting that Ficoll would be a better probe of glomerular pore size than the commonly used dextran. To examine the differences between these macromolecules in vivo, the fractional clearances of tritiated Ficoll and dextran were measured over a wide range of molecular sizes (Stokes-Einstein radius, rs, from 19 to 65 A) in normal euvolemic Munich-Wistar rats. Whole-kidney and single-nephron hemodynamic conditions were characterized through a combination of clearance and micropuncture measurements. The fractional clearance, or sieving coefficient (theta), for dextran significantly exceeded that of Ficoll at all molecular sizes examined, theta for dextran being approximately 10 times that for Ficoll for rs greater than 30 A. Thus, the results with Ficoll imply a more size-restrictive barrier than do the results with dextran. The values of theta for Ficoll approximated previously reported values for uncharged globular proteins. Although theta for Ficoll at rs = 35 A was much smaller than the corresponding value for dextran, it was still approximately 30 times greater than typical values of the filtrate-to-plasma concentration ratio reported for serum albumin (a polyanion) in the rat, in agreement with the concept that glomerular charge-selectivity normally plays an important role in the prevention of albuminuria. Three membrane-pore models were compared in their ability to represent the dextran and Ficoll sieving data. A lognormal pore-size distribution in parallel with a nonselective "shunt" pathway was found to be more effective than either an isoporous membrane with a shunt or a purely lognormal distribution. On the basis of these laboratory results and computations, Ficoll may be preferred over dextran in future studies of glomerular size-selectivity.