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Biomedical subjects

W Meyer

Publications and source records attributed to W Meyer.

At least 253 records · Page 14Linked to original sources
PubMed1989

A quantitative histochemical study of delta 5-3 beta-hydroxysteroid dehydrogenase and succinate dehydrogenase activities in the bovine corpus luteum of pregnancy.

In corpora lutea of pregnancy of dairy cows delta 5-3 beta-hydroxysteroid dehydrogenase and succinate dehydrogenase were demonstrated histochemically and evaluated densitometrically. Serum progesterone was determined radioimmunologically. Activities per volume unit of delta 5-3 beta-hydroxysteroid dehydrogenase and succinate dehydrogenase in large and small luteal cells as well as progesterone concentrations, exhibited no typical and correlated pattern during pregnancy. Large luteal cells in regressive tissue regions showed weaker delta 5-3 beta-hydroxysteroid dehydrogenase activities than in maturing or well-developed tissue regions. Succinate dehydrogenase activities of small luteal cells were highest in regressive luteal tissue. The results indicate that structural development of bovine luteal tissue during pregnancy is reflected by corresponding enzyme activities.

3-Hydroxysteroid Dehydrogenases↗
PubMed1989

Regional histochemical aspects of xanthine oxidase activity in ischemic and reperfused small intestine of the rat.

The study describes regional changes of xanthine oxidase and succinate dehydrogenase activities as shown by the ischemic and reperfused small intestine of the rat. The results are obtained with enzyme histochemical methods, including densitometrical verifications, and are substantiated with biochemical enzyme determinations. The decrease of xanthine oxidase activity was best visible in the anoxic duodenum and jejunum, where the findings of histochemical enzyme determinations agreed with those achieved biochemically. The activities of succinate dehydrogenase as measured densitometrically may serve as a further control, considering also the typical intracellular distribution of the reaction products.

Animals↗
PubMed1989

Histochemical study on the eccrine glands in the foot pad of the cat.

Enzyme and carbohydrate histochemical methods were used to study the secretory activities and secretion properties of the eccrine tubular glands in the foot pad of the cat. The activity spectra of the different oxidative and hydrolytic enzymes investigated indicate high metabolic rates within the secretory epithelium. Additionally the enzyme reactions emphasize a double innervation of the glands by cholinergic and adrenergic nerve fibres. The carbohydrate histochemical differentiation reveals mostly neutral and very few acidic glycoproteins in the secretory cells and the secretion, respectively. Clear (basal) cells contain distinct amounts of glycogen, and dark (superficial) cells show neutral glycoproteins, which reveal after PO-lectin-DAB procedures the following saccharide residues: alpha-D-mannose, alpha-D-galactose, N-acetyl-alpha-D-glucosamine, alpha-L-fucose, beta-D-galactose-D-N-galactosamine, beta-D-galactose, and sialic acid. The results obtained confirm the view that the normal biological functions of the eccrine glands of the feline foot pad are to improve the frictional capacities of the paw and to leave typical scent marks.

Animals↗
PubMed1988

[Villous adenoma of the papilla of Vater and acute necrotizing pancreatitis].

In two patients a villous adenoma of the papilla of Vater was found to be the cause of an acute necrotizing pancreatitis. The diagnosis was largely made by early gastroduodenoscopy and endoscopic retrograde cholangiopancreatography. After initially conservative treatment of the pancreatitis the adenoma was excised transduodenally in both patients. Histological examination in both revealed a completely removed benign villous adenoma. Both patients have remained free of symptoms after 18 and 6 months, respectively. These observations support the call for intensive diagnostic measures when a diagnosis of pancreatitis has been made: tumours of the pancreas and of the periampullar region should be ruled out.

Acute Disease↗
PubMed1988

Removal of methotrexate, leucovorin, and their metabolites by combined hemodialysis and hemoperfusion.

This article documents the case of a patient with severe renal failure immediately after having been given high-dose methotrexate; the patient was effectively treated with repeated hemodialysis, charcoal hemoperfusion, leucovorin, and thymidine. The methotrexate plasma concentration was reduced from 390 mumol/L to 7 mumol/L as a result of 24.5 hours of hemodialysis along with 39.5 hours of hemoperfusion. Although a rebound in the plasma methotrexate concentration occurred the first three times that hemodialysis and/or hemoperfusion was stopped, reinstitution of the procedure was always effective in further lowering methotrexate concentrations. The patient was subsequently managed with leucovorin and thymidine rescue. Simultaneous measurements before and after the hemodialysis-hemoperfusion apparatus and before and after the hemoperfusion device alone revealed a percent decrease in the concentration of d-leucovorin of 36% and 79%; 1-leucovorin, 82% and 75%; 5-methyltetrahydrofolate, 52% and 64%; methotrexate, 73% and 37%; and 7-hydroxymethotrexate, 21% and 24%, respectively. Gastrointestinal and hematologic toxicities were completely prevented, and serum creatinine normalized within 24 days.

Adolescent↗
PubMed1988

The pulsed dye laser versus the Q-switched Nd:YAG laser in laser-induced shock-wave lithotripsy.

To date, there are two fairly well-established alternatives for laser-induced shock-wave lithotripsy in clinical practice. The Q-switched Nd:YAG laser is distinguished by the high-stone selectivity of its coupler systems. The necessity of a coupler system and its fairly small conversion rate of light energy into mechanical energy present serious drawbacks. Furthermore, the minimal outer diameter of the transmission system is 1.8 mm. The pulsed-dye laser can be used with a highly flexible and uncomplicated 200-micron fiber. However, the laser system itself is more complicated than the Q-switched Nd:YAG laser and requires a great deal of maintenance. Biological evaluation of damage caused by direct irradiation shows that both laser systems produce minor damage of different degrees. YAG laser lithotripsy with the optomechanical coupler was assessed in 31 patients with ureteral calculi. The instability and limited effectiveness of the fiber application system necessitated auxiliary lithotripsy methods in 14 cases. Dye-laser lithotripsy is currently being tested in clinical application. Further development, such as systems for blind application or electronic feedback mechanisms to limit adverse tissue effects, have yet to be optimized. Nevertheless, laser-induced shock-wave lithotripsy has the potential to become a standard procedure in the endourologic management of stone disease.

Animals↗
PubMed1988

Mechanism of action and cardiotonic activity of a new phosphodiesterase inhibitor, the benzimidazole derivative adibendan (BM 14.478), in guinea-pig hearts.

1. The effects of adibendan (BM 14.478; 7,7-dimethyl-2-(4-pyridyl)-6,7-dihydro-3H,5H-pyrrolo[2,3-f] benzimidazole-6-one) on force of contraction and beating frequency were analysed in guinea-pig electrically driven papillary muscles and spontaneously beating right auricles, respectively. The effects of 3-isobutyl-1-methylxanthine (IBMX) and milrinone were studied for comparison. 2. Adibendan exerted a concentration-dependent (0.03-300 mumol/l) positive inotropic effect in papillary muscles (EC50 = 1.3 mumol/l) which was only partially reversible. The efficiency of adibendan was less than that of milrinone, but adibendan was about two orders of magnitude more potent and had only slight positive chronotropic effects (113% of pre-drug values) at most. Milrinone increased the frequency of beating maximally to 140% of pre-drug values. The positive inotropic effect of adibendan is probably at least partially mediated by cAMP since carbachol reduced the increase in force of contraction by about 75%. 3. To elucidate the mechanism of action of adibendan we investigated its effects on phosphodiesterase I-III and adenylate cyclase activity in isolated preparations from guinea-pig hearts. 4. Adibendan selectively inhibited phosphodiesterase III (PDE III) activity concentration-dependently (IC50 = 2.0 mumol/l). The IC50 values for the inhibition of PDE I or II were more than 60-fold higher. Since adibendan did not affect adenylate cyclase activity a stimulation of the cAMP synthesis as a mechanism of action can be ruled out. 5. The results provide evidence that the positive inotropic action of adibendan is at least in part due to an inhibition of cAMP-PDE III.(ABSTRACT TRUNCATED AT 250 WORDS)

1-Methyl-3-isobutylxanthine↗
PubMed1988

The cytochemistry of glycoconjugates in the planum nasolabial gland of the goat as studied by electron microscopic methods.

In the planum nasolabial glands of the goat, glycoconjugates of glandular and duct cells have been studied by means of a series of electron microscopic cytochemical methods. In the glandular cells glycoconjugates with vicinal diol groupings were present in secretory granules, certain elements of the Golgi complex, lysosome-like dense bodies, the surface coat of the plasma membrane, the majority of intracellular cytomembranes, glycogen particles and the basal lamina. In duct cells, glycoconjugates with the same properties were localized in similar ultrastructures, except for secretory granules, which were not detected in these cells. By lectin cytochemistry, glycoconjugates in glandular cell secretory granules contained a variety of saccharide residues such as alpha-D-mannose, alpha-D-glucose, N-acetyl-D-glucosamine and alpha-L-fucose. The cytochemical properties of the secretory glycoconjugates are discussed in relation to the physiological functions performed by the planum nasolabial glands in the goat.

Animals↗
PubMed1988

Selective inhibition of cAMP phosphodiesterase III activity by the cardiotonic agent saterinone in guinea pig myocardium.

The effects of saterinone [+/-)-1,2-dihydro-5-[4-[2-hydroxy-3-[4-(2-methoxyphenyl)-1-piperazinyl] propoxy] phenyl]-6-methyl-2-oxo-3-pyridine-carbonitrile, BDF 8634) on force of contraction, beating frequency, and on phosphodiesterase (PDE) activity were investigated in isolated preparations from guinea pig hearts. The effects of 3-isobutyl-1-methylxanthine (IBMX) and milrinone were studied for comparison. Saterinone exerted a concentration-dependent (1-30 mumol/l) positive inotropic effect (EC50 = 9.1 mumol/l) in guinea pig papillary muscles. The drug was more potent in increasing force of contraction than was milrinone, but its efficacy was only half as great as that of milrinone. Also IBMX revealed an about 4-fold greater positive inotropic efficacy than saterinone. This study provides functional evidence that the positive inotropic effect of saterinone is at least partially due to a cyclic adenosine monophosphate (cAMP)-dependent mechanism because carbachol antagonized the increase in force of contraction completely. In order to elucidate a possible mechanism of action of saterinone its effects on cardiac cAMP PDE activity were investigated. Saterinone selectively and potently inhibited the isoenzyme III of PDE (IC50 = 0.06 mumol/l). The mean IC50-values for the inhibition of PDE I and II were 323-fold greater. Thus, saterinone proved to be a selective inhibitor of "low-Km, cAMP specific" PDE III. Saterinone revealed only a moderate positive chronotropic effect. The beating frequency of guinea pig spontaneously beating right auricles was augmented by 26.4% at most, that is half as much as the effect of isoprenaline at a similarly effective positive inotropic concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1988

Interferon gamma in rheumatoid arthritis--a double blind study comparing human recombinant interferon gamma with placebo.

A double blind trial comparing recominant interferon gamma (IFN gamma) with placebo in rheumatoid arthritis is presented. Twenty-six patients entered the study and 22 completed the 6-month period. IFN gamma was administered subcutaneously as was placebo; the 1st week, patients treated with the active compound received a daily subcutaneous injection of 100 micrograms of IFN gamma and for the following 23 weeks the schedule was decreased to 2 injections of 100 micrograms every week. No serious side effects were observed. After Week 24 the group treated with the active compound showed a significant decrease of the joint tenderness score and the placebo group showed a significant increase of the number of subcutaneous nodules. All other variables shifted in favour of the active compound but not significantly. More double blind trials with a larger number of patients and using other treatment schedules or other routes of administration are required.

Arthritis, Rheumatoid↗
PubMed1988

Delta 5-3 beta-hydroxysteroid dehydrogenase, succinate dehydrogenase and glucose-6-phosphate dehydrogenase in the bovine corpus luteum of estrous cycle: a quantitative histochemical study.

Genital organs and blood were obtained from dairy cows at a local abattoir. 3 recently ovulated follicles and 20 corpora lutea of estrous cycle (CLC) were used for the quantitative enzyme histochemical demonstration of delta 5-3 beta-hydroxysteroid dehydrogenase (3 beta-OHSDH), succinate dehydrogenase (SDH) and glucose-6-phosphate dehydrogenase (G-6-PDH) activity, employing a computerized microscope photometer. Progesterone was determined in blood serum by radioimmunoassay. Luteal tissue was grouped into several stages of development according to micromorphological criteria. Activities per volume unit of 3 beta-OHSDH and SDH in large luteal cells (LLC), as well as in small luteal cells (SLC), and luteal tissue (LT), relative amounts of the 3 beta-OHSDH-positive tissue fraction (PLCC), and progesterone concentrations in blood serum exhibited a significant pattern corresponding to the morphological development of the endocrine gland. G-6-PDH showed an increase in activity per volume unit during tissue development lasting until the beginning of regressive changes, and as significant in LLC and LT. Activities per volume unit of 3 beta-OHSDH (p less than or equal to 0.001) and SDH (p less than or equal to 0.01) were higher in LLC than in SLC, indicating superior steroidogenic capacities, while G-6-PDH activity was distinctly higher in the latter (p less than or equal to 0.001). Almost all parameters tested were correlated positively. 3 beta-OHSDH and SDH exhibited a significantly positive correlation in LLC (p less than or equal to 0.01) and LT (p less than or equal to 0.001) during periods of measureable progesterone secretion. In SLC this correlation was nonsignificant (p greater than 0.05). G-6-PDH showed a relative poor correlation to 3 beta-OHSDH (LLC, p less than or equal to 0.05; LT, p less than or equal to 0.01) and SDH (LT, p less than or equal to 0.05). Enzyme activities in LLC as well as in SLC were generally positively correlated (p less than or equal to 0.001). All enzymes tested exhibited a significantly positive correlation with progesterone concentrations in blood serum. This was significant for SDH only during measurable progesterone secretion, and less marked for G-6-PDH.

3-Hydroxysteroid Dehydrogenases↗
PubMed1988

Investigational study of iodine-124 with a positron camera.

A case is presented where I-124 produced by a clinical cyclotron was used with a positron emission tomography camera for clinical usage. This represents the first report of the utilization of this modality with this radionuclide. We feel the increased spatial resolution of PET should be of value in looking at thyroid disease.

Carcinoma↗
PubMed1987

[Unusual cases of coronary death].

Stenosing coronary artery sclerosis is the most common cause of sudden unexpected death. In this report we present three exceptions: 1. A mycotic coronary aneurysm ruptures and results in pericardial tamponade; 2. in a young woman Takayasu aortitis encroaches on the ostium and mainstem of the left coronary; 3. fibromuscular dysplasia of the right coronary artery causes death in a 56-year-old male.

Adult↗
PubMed1987

Histochemical observations on the apocrine glands of the scrotal skin of the cat and dog.

Enzyme and carbohydrate histochemical methods were used to study the secretory activity of the apocrine glands of the scrotal skin of the cat and dog. The typical activity spectra of the different oxidative and hydrolytic enzymes investigated indicated high metabolic rates within the secretory cells. The carbohydrate histochemical differentiation revealed mostly neutral and partly acidic glycoproteins, with only small amounts of sialic acid, in the secretory cells and the luminal secretion of the glands. The PO-lectin-DAB procedures applied demonstrated that the following saccharide residues were dominant within the neutral glycoproteins present: alpha-D-glucose, alpha-D-mannose, beta-D-galactose, N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine.

Animals↗