PubMed Health⌕ Search

Biomedical subjects

W Roth

Publications and source records attributed to W Roth.

At least 55 records · Page 3Linked to original sources
PubMed1985

A tubal plug and clip method for female sterilization.

Animal studies using rabbits, stumptailed macaques monkeys, and baboons demonstrate that the tubal plug and clip device is an effective and safe method for female sterilization in these animal models. The devices were placed in 18 baboons that were bred regularly for six to 18 months without conception. Ten of these 18 animals conceived within 12 months after removal of the devices and carried normal pregnancies without any other surgical procedure. Six of the ten animals conceived and carried a second pregnancy for a total of 16 successful pregnancies. The expected pregnancy rate for baboons is 64.9% per year so that the 55.6% success rate of reversal and 16 total pregnancies clearly represents a high degree of reversibility for the method in this animal species.

Animals↗
PubMed1984

Isoelectric focusing--polynucleotide/polyacrylamide-gel electrophoresis. A technique to separate and characterize nuclease activities.

Individual native nuclease activities from human leucocytes are separated by using two-dimensional gel electrophoresis in an apparatus that allows the simultaneous running of 28 gels. Proteins are separated by isoelectric focusing in a disc gel, followed by electrophoresis into a slab gel containing DNA. Protein denaturants are avoided in the second dimension by the use of a running pH well above the optimal pH for DNAase (deoxyribonuclease) activity. Electrophoresed gels are incubated in appropriate buffers to activate nuclease activity. After staining for intact DNA, the positions of active enzymes, unobscured by the presence of other proteins, are revealed as colourless spots in a reddish-purple field. The technique is easy to use and is sensitive to 50pg of DNAase I. Versatility is provided by the use of either acidic or basic electrophoresis running buffers and by the use of specific gel incubation conditions to reveal different sets of enzyme activities. Two DNAases active at pH 7.4 in the presence of Mg2+ and Ca2+, and sixteen DNAases active at acidic pH and not requiring metals, are detected. Treatment of the human enzymes with specific glycosidases reveals that many of the human DNAases are glycoproteins containing negatively charged moieties and may be derived from modification of parent activities.

Deoxyribonucleases↗
PubMed1983

Rapid, sensitive and fully automated high-performance liquid chromatographic assay with fluorescence detection for sulmazole and metabolites.

Sulmazole (2-[(2-methoxy-4-methylsulfinyl)phenyl]-3H-imidazo [4,5-b] pyridine; AR-L 115 BS) and two metabolites (sulfide, sulfone) were quantified from directly injected body fluids (plasma, urine, bile) after high-performance liquid chromatographic separation. No internal standard is needed, which is particularly advantageous when fluorescence detection is established. After automated pre-column enrichment on Corasil C18 (37-50 microns), the parent compound and biotransformation products could be backflushed and chromatographed on ODS-Hypersil (5 microns) with a mixture of 0.075 mol/l phosphate buffer-acetonitrile (2:1), an elution rate of 2.0 ml/min and fluorimetric detection (lambda ex = 330 nm; lambda em = 370 nm). A hydroxylated metabolite of sulmazole which occurs preferentially in urine (and bile) can be quantified in the above-mentioned solvent system diluted 1:1 with water, but with different fluorescence characteristics (lambda ex = 345 nm; lambda em = 515 nm). The assay was linear in the range 8-1000 ng/ml. The lower limit of detection was about 8 ng/ml or 80 pg with coefficients of variation between 0.4 and 5.8% for sulmazole.

Animals↗
PubMed1983

Nonlinear pharmacokinetics of the new positive inotropic agent sulmazole in the dog.

Sulmazole (I) 2-[2-methoxy-4-(methylsulfinyl)phenyl]-1H-imidazo[ 4,5-b]pyridine, a new positive inotropic agent, is based on a pyridoimidazole nucleus. Sulmazole pharmacokinetics were monitored in plasma and urine by a specific, sensitive reverse-phase fully automated HPLC system with fluorimetric detection. The hydroxylated metabolite, III, was also monitored in the urine, and unusual pharmacokinetics were observed. Sulmazole disappeared and metabolite II appeared in plasma by zero-order rates for most of their time courses in the 2-15-mg/kg range with a 75% conversion to II. Pure Michaelis-Menten pharmacokinetics were not applicable, and the vmax value increased with increasing dose. Pharmacokinetics of sulmazole and II at 0.7-mg/kg iv doses were characterized by a first-order two-compartment body model. Metabolite III at 0.7- and 2-mg/kg iv doses showed no dose-dependent pharmacokinetics. The unchanged drug and its major metabolite, II, were negligibly excreted renally (0.5-2%). Their renal clearance showed urine flow rate dependencies. The plasma protein bindings were: sulmazole, 40.8 +/- 1.0%; II, 54 +/- 2%; III, 43 +/- 1%, and they were concentration independent.

Animals↗
PubMed1983

[A case of arthritis caused by a tick bite (Lyme arthritis)].

A typical case of arthritis in the knee joint of a 49-year-old man caused by tick bite is reported. Based on this case report the manifestations of arthritis after erythema chronicum migrans so far published in literature are described.

Arthritis, Infectious↗
PubMed1981

Fully automated high-performance liquid chromatography. A new chromatograph for pharmacokinetic drug monitoring by direct injection of body fluids.

A new fully automated high-performance liquid chromatography is described which detects drugs from directly injected plasma (urine, saliva) without sample pretreatment. The apparatus consists of a programmable automatic sampling unit, which is connected via two alternating working pre-columns to an analytical column ("alternating pre-column sample enrichment"). The new device is able to operate with directly injected body fluids like an auto-analyzer and is especially useful for pharmacokinetic and clinical studies, where drug concentrations have to be determined from plasma, urine or saliva.

Body Fluids↗
PubMed1981

[AR-L 115 BS, comparison of human metabolite pattern and biotransformation with other species].

Following oral administration of 14C labelled 2-[(2-methoxy-4-methylsulfinyl)phenyl]-1H-imidazo[4,5-b]pyridine (AR-L 115 BS) to the rat, rabbit, dog, rhesus monkey, baboon and man the metabolic pattern in plasma and urine was compared and human urinary metabolites were isolated. None of the animal species investigated shows a metabolic pattern identical to that of man. The plasma of rat, dog and rabbit shows wide variation of metabolites with high amounts of two unpolar metabolites of AR-L 115 BS (sulfoxide), namely M0/2 identical with AR-L 114 BS (sulfone with regard to AR-L 115 BS) and M0/1 identical with AR-L 113 BS (sulfide). In comparison to man the urines of the animals show higher amounts of the sulfone (AR-L 114 BS) and the sulfide (AR-L 113 BS). A main pathway of the metabolism of the pyrido-imidazole of the AR-L 115 BS-type is the oxidative pyridine-ring cleavage leading to N-acetylated 5-aminoimidazoles. Further metabolites are characterised by a hydroxyl group in the 6-position of the pyrido-imidazole moiety. Besides the oxidation of tthe sulfoxide function to the sulfone we could also observe the thioether (sulfide) not only of the parent compound itself but also of some of the metabolites in the series of the AR-L 115 BS-biotransformation. The identification of the human urinary metabolites, was carried out by means of TLC, HPLC, UV-, MS- and NMR-spectroscopy.

Administration, Oral↗