Biomedical subjects

P Rozman

Publications and source records attributed to P Rozman.

8 recordsLinked to original sources

PubMed1999

Genotyping for human platelet-specific antigens HPA-1, -2, -3, -4 and -5 in the Slovenian population reveals a slightly increased frequency of HPA-1b and HPA-2b as compared to other European populations.

Typing of human platelet alloantigens (HPA) is necessary in various clinical situations. The purpose of this study was to type a random sample of the Slovenian population for HPA alleles, in order to obtain genetic population data. A total of 152 unrelated Slovenian blood donors were genotyped for HPA-1, -2, -3, -4 and -5 alleles using a simple method that enables simultaneous and complete determination of HPA genotypes. Ten different polymerase chain reactions employing sequence-specific priming (PCR-SSP), which worked in identical cycling conditions, were used. The allele frequencies were 0.809 for HPA-1a, 0.191 for HPA-1b, 0.891 for HPA-2a, 0.109 for HPA-2b, 0.591 for HPA-3a, 0.407 for HPA-3b, 0.997 for HPA-4a, 0.00 for HPA-4b, 0.934 for HPA-5a and 0.066 for HPA-5b. When compared to results of studies of various other Caucasian populations, our population displayed a slightly but not significantly higher proportion of the HPA-1b and 2b alleles.

Antigens, Human Platelet↗

PubMed1996

Cultivation of mouse-mouse hybridomas producing IgM monoclonal antibodies.

The mouse-mouse hybridomas producing monoclonal antibodies (MAbs) for ABO blood group determination were cultivated for 10 days in 25 cm2 Roux bottles using standard cultivation medium (DMEM) with different foetal-calf serum (FCS) concentrations (2-13%). The highest specific production rates (200-1100 micrograms/10(6) cells/day) for MAbs were measured at the end of the cultivation: this phenomenon could be explained by advanced cell death and liberating the content of the cells into the medium.

ABO Blood-Group System↗

PubMed1995

Acetaminophen does not decrease hepatic 3'-phosphoadenosine 5'-phosphosulfate in mice.

Capacity-limited sulfation of chemicals is thought to be due to the limited availability of 3'-phosphoadenosine 5'-phosphosulfate (PAPS), the cosubstrate for sulfation, which in turn is limited by the availability of its precursor, inorganic sulfate. Because this concept evolved from experimental data obtained from rats, and species differences have also been reported on acetaminophen (AA) sulfation, this study examined the effects of AA on PAPS and sulfate concentrations in mice, another widely used experimental animal. AA lowered serum and liver sulfate concentrations approximately 50% in mice. However, contrary to observations in rats, AA (0-600 mg/kg i.p.) did not decrease hepatic PAPS concentrations in mice. In summary, these studies demonstrate that AA decreases serum and liver sulfate concentrations, but does not decrease hepatic PAPS concentrations in mice. These data indicate that 1) hepatic sulfation of high dosages of AA in mice is not limited by the availability of PAPS, and 2) there are significant species differences in the regulation of AA sulfation between rats and mice.

Acetaminophen↗

PubMed1992

Tissue sulfate determination by ion chromatography.

The application of controlled-flow anion chromatography to assay inorganic sulfate in biological fluids and tissues is described. The eluent used in previous methods for analyzing sulfate in biological fluids has been modified by adding 4.5% acetonitrile to separate sulfate from a co-eluting peak. To markedly increase the life of the column, the tissue samples were further diluted, extracted with chloroform, and analyzed at a lower detection range (0.3 microS). The method has been shown to be applicable for determining sulfate in tissues as well as biological fluids.

Animals↗

PubMed1992

Homeostasis of sulfate and 3'-phosphoadenosine 5'-phosphosulfate in rats after acetaminophen administration.

Acetaminophen (AA) is a drug whose biotransformation by sulfation is easily saturated. We have previously demonstrated in rats that its dose-dependent kinetics appear to be due to depletion of 3'-phosphoadenosine 5'-phosphosulfate (PAPS). In order to determine if the depletion of PAPS might be due to a lack of inorganic sulfate, we characterized the effect of AA not only on the homeostasis of PAPS but also on its precursor, sulfate. The maximum excretion of AA-sulfate was observed after 75 mg/kg of AA, i.p., and higher dosages did not increase its excretion. AA dosages between 150 to 600 mg/kg, i.p., 2 hr after dosing depleted 60 to 80% of hepatic PAPS. Hepatic PAPS levels returned to control values 16 to 20 hr after dosing with 600 mg/kg of AA. AA decreased serum sulfate to a similar degree (80%) and duration (16 hr) as did hepatic PAPS. AA also lowered sulfate concentrations in liver, but to a somewhat lesser extent (65%) than in serum. Hepatic sulfate levels returned to control values at 16 to 24 hr after dosing with AA. Even though AA did not alter renal PAPS concentrations, it did produce a 65% decrease in the renal sulfate levels. In summary, these studies demonstrate that AA markedly depletes PAPS concentrations in liver, but not in kidney, and drastically decreases serum and tissue sulfate concentrations. Our findings indicate that the capacity-limited sulfation of AA is due to the limited availability of hepatic PAPS, which in turn is limited by the availability of sulfate in liver.

Acetaminophen↗

PubMed1986

Reduced serum thyroid hormone levels in hexachlorobenzene-induced porphyria.

The effect of feeding 0.1% hexachlorobenzene (HCB) for 55 days on mortality, body weight, urinary porphyrin excretion, serum thyroid hormones and induction of liver microsomal enzymes was studied in female Sprague-Dawley rats. This dosage regimen, followed by 42 days of a regular diet, resulted in 33% mortality with a mean time to death of 67 +/- 4 days. Body weight of survivors was not affected by dietary HCB, whereas non-survivors underwent a rapid weight loss (wasting) prior to death. At the end of the dosing period (day 55), rats fed the HCB diet exhibited an increase in the excretion of urinary porphyrins (4-fold) and a significant decrease in the levels of serum thyroxine (T4) and triiodothyronine (T3). When rats were returned to a regular diet the excretion of urinary porphyrins continued to rise (approx. 100 times higher than controls) and serum thyroid hormones remained suppressed. At the end of the experiment (day 97), the concentration of liver microsomal cytochrome P-450 and cytochrome bs and the activity of ethoxyresorufin-O-deethylase, pentoxyresorufin-O-dealkylase, aminopyrine-N-demethylase and UDP-glucuronosyl transferase were significantly induced, whereas the activity of NADPH-cytochrome c reductase and benzo[a]pyrene hydroxylase was not. Results demonstrate that HCB-induced lethality and porphyria occur by different mechanisms, reduced T4 and T3 serum levels accompany induction of porphyria by HCB, and induction of aryl hydrocarbon hydroxylase (with benzo[a]pyrene as substrate) is not a sensitive indicator of HCB exposure.

Administration, Oral↗

PubMedDate not supplied

Homeostasis of sulfate and 3'-phosphoadenosine 5'-phosphosulfate in rats with deficient dietary intake of sulfur.

This study was designed to determine the role of dietary organic and inorganic sulfur on 3'-phosphoadenosine 5'-phosphosulfate (PAPS) homeostasis. Organic sulfur was altered by adding various amounts of methionine (0.15, 0.3, 0.6, or 1.2%) to a sulfhydryl-deficient diet. Inorganic sulfur was altered by providing rats with no sulfate or sulfate in their diets (0.12%) and distilled or tap water. Rats received these diets for 5 days. The two lowest methionine-containing diets produced a 60% reduction in liver glutathione concentrations, and the addition of sulfate to the diets did not restore hepatic glutathione levels. Urinary sulfate excretion was reduced by 95% in rats fed the three low-methionine diets. Addition of sulfate to these diets increased the urinary excretion of sulfate, but did not return sulfate levels to control values. The three low-methionine-containing diets decreased serum and liver sulfate concentrations about 50% and addition of sulfate to these diets largely restored them to control levels. Hepatic PAPS concentration was decreased (10%) only in the group receiving the lowest methionine content in their diet, and addition of sulfate had no effect on hepatic PAPS. In summary, dietary alterations of sulfur lowered the glutathione concentration in the liver as well as decreased sulfate levels in serum, liver, and urine, but had minimal effect on hepatic PAPS concentrations. Therefore, it appears that hepatic steady-state PAPS levels are not highly dependent on the sulfur content of the diet.

Amino Acids↗

PubMedDate not supplied

Sulfation of acetaminophen and acetaminophen-induced alterations in sulfate and 3'-phosphoadenosine 5'-phosphosulfate homeostasis in rats with deficient dietary intake of sulfur.

Sulfation of drugs depends on the availability of 3'-phosphoadenosine 5'-phosphosulfate (PAPS), which requires inorganic sulfate for its synthesis. Therefore, decreased alimentary intake of inorganic sulfate or its precursor, cysteine, may compromise sulfation of xenobiotics. To test this hypothesis, separate groups of rats were maintained for 5 days on synthetic diets, which lacked sulfate, or cysteine, or both sulfate and cysteine. These dietary restrictions did not cause growth retardation or depletion of glutathione in liver. Under anesthesia, the animals were injected with acetaminophen (0.5 mmol/kg, i.v.) and elimination of acetaminophen from blood and excretion of acetaminophen metabolites in urine and bile was simultaneously quantified. Deficient intake of inorganic sulfate or cysteine alone did not significantly change elimination and biotransformation of acetaminophen. Combined nutritional deficiency of sulfate and cysteine, however, resulted in a 40% reduction in the excretion of acetaminophen-sulfate, quantitatively the most significant metabolite. Concomitantly, these animals eliminated acetaminophen from blood at a slower rate and converted more acetaminophen to its toxic intermediate, as indicated by increased excretion of acetaminophen-thioether conjugates. Serum and tissue sulfate concentrations were decreased to significantly lower levels in rats on sulfate and cysteine deficient diets, than in rats with a sufficient sulfur supply. Thus, reduced sulfation is apparently caused by diminished availability of inorganic sulfate for PAPS synthesis, even though hepatic and renal PAPS levels were not depleted more by acetaminophen in rats with deficient dietary supply of sulfate and cysteine than in rats with adequate sulfur intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaminophen↗