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Biomedical subjects

B Mayer

Publications and source records attributed to B Mayer.

At least 361 records · Page 20Linked to original sources
PubMed1986

Possible inhibitory function of endogenous 15-hydroperoxyeicosatetraenoic acid on prostacyclin formation in bovine aortic endothelial cells.

Arachidonic acid is metabolized via the cyclooxygenase pathway to several potent compounds that regulate important physiological functions in the cardiovascular system. The proaggregatory and vasoconstrictive thromboxane A2 produced by platelets is opposed in vivo by the antiaggregatory and vasodilating activity of prostacyclin (prostaglandin I2) synthesized by blood vessels. Furthermore, arachidonic acid is metabolized by lipoxygenase enzymes to different isomeric hydroxyeicosatetraenoic acids (HETE's). This metabolic pathway of arachidonic acid was studied in detail in endothelial cells obtained from bovine aortae. It was found that this tissue produced 6-ketoprostaglandin F1 alpha as a major cyclooxygenase metabolite of arachidonic acid, whereas prostaglandins F2 alpha and E2 were synthesized only in small amounts. The monohydroxy fatty acids formed were identified as 15-HETE, 5-HETE, 11-HETE and 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT). The latter two compounds were produced by cyclooxygenase activity. Nordihydroguaiaretic acid (NDGA), a rather selective lipoxygenase inhibitor and antioxidant blocked the synthesis of 15- and 5-HETE. It also strongly stimulated the cyclooxygenase pathway, and particularly the formation of prostacyclin. This could indicate that NDGA might exert its effect on prostacyclin levels by preventing the synthesis of 15-hydroperoxyeicosatetraenoic acid (15-HPETE), a potent inhibitor of prostacyclin synthetase. 15-HPETE could therefore act as an endogenous inhibitor of prostacyclin production in the vessel wall.

Animals↗
PubMed1986

[Regulation of nasal resistance in children].

By means of active anterior rhinorheomanometry we searched for nasal cycles in children of 3-10 years of age. We measured the nasal air flow every 15 minutes for a period of 2 hours on both sides in relation to a pressure of 1 mbar. In the group of the 7-10 year old children we found nasal cycles in 79 per cent according to Hasegawa's and Kern's definition. In contrast to other authors nasal cycles were also ascertained in 50 per cent of the 3-6 year old children: Computing the correlation coefficient between the difference of one measurement from the right and left mean nasal air flow, we could demonstrate that the nasal cycle was actually subject to a regulatory mechanism. In contrast "solidary movements" showed no regulation in our challenge-controlled measurements.

Airway Resistance↗
PubMed1986

[Value of conventional tomography and computer tomography in therapy-resistant diseases of the paranasal sinuses].

The informational value of conventional tomography as primary diagnostic method is pointed out in diseases of nasal sinuses resistant to therapy. 5 cases demonstrate the additional information gained by CT-differentiation of soft tissue structures, intraorbital and intracranial expansion. In 78.4% of the examined group of 51 patients conventional tomography allowed the diagnosis of a process limited to the nasal sinuses, further evidence by CT could be omitted. In 11 patients examined by CT additionally, the expansion of the process was defined more precisely and the assumed intraorbital and intracranial growth confirmed.

Adolescent↗
PubMed1985

Qualitative and quantitative measurement of hydroxy fatty acids, thromboxanes and prostaglandins using stable isotope dilutions and detection by gas chromatography-mass spectrometry.

Methods for measurement of the metabolites of arachidonic acid (AA), namely prostaglandins (PGs), thromboxanes (TXs) and hydroxy fatty acids, using stable isotope dilution gas chromatography--mass spectrometry are described. With a few exceptions, labelled species of the various AA metabolites are not commercially available and were therefore synthesized in our laboratory. [2H8]AA, produced by deuteration of eicosatetraynoic acid, was used for comparing the metabolism of exogenously added and endogenously present AA in fibroblast cultures. After derivatization and catalytic hydrogenation, structure elucidation and quantification of the different hydroxy fatty acids was carried out by determination of the fragment ions resulting from alpha-cleavage at the site of the hydroxy function. During catalytic hydrogenation a significant hydrogen--deuterium exchange was observed. To eliminate this problem, 18O-labelled standards were prepared by exchanging the oxygen of the carboxylic acid group. The preparation and the use of hydroxy fatty acids, PGs and TXs labelled with 18O is described.

Fatty Acids↗
PubMed1985

The effects of antimitotic and microfilament disrupting agents on functions of isolated guinea-pig parietal cells.

In isolated guinea-pig parietal cells pretreated for 60 min with the H2-antagonist ranitidine, the antimitotic agents colchicine and vinblastine, the microfilament-disrupting agent cytochalasin B resulted in a concentration-dependent inhibition of histamine-stimulated acid secretion up to 80%. Ranitidine reduced histamine binding to the membrane located H2-receptor. The anti-cytoskeletal agents inhibited the cellular histamine uptake but did not effect the histamine methyltransferase activity which was significantly reduced by ranitidine. The data suggest that cytoskeletal elements like microtubules and microfilaments are of very specific functional significance not only in the secretory process of the parietal cell but also for cellular transport mechanisms.

Animals↗
PubMed1985

Proteinase K from Tritirachium album limber. I. Molecular mass and sequence around the active site serine residue.

The molecular mass of proteinase K was determined by gel electrophoresis in the presence of sodium dodecyl sulfate and by active site labelling with diisopropyl fluorophosphate. Both methods indicate molecular masses in the range of 27 000-29 000 Da. These values differ significantly from that of 18 500 formerly determined by gel filtration (Ebeling et al. (1974) Eur. J. Biochem. 47, 91-97). Proteinase K was inactivated with [3H]diisopropyl fluorophosphate. Afterwards the labelled protein was reduced, S-carboxymethylated and digested with cyanogen bromide. The chain lengths of the isolated CNBr-fragments are indicative of a molecular mass of proteinase K of at least 28 000 Da. Two CNBr-fragments were sequenced. The radioactively labelled fragment contains 69 residues and the sequence around the labelled residues was found to be -Ile-Ser-Gly-Thr-SER-Met-Ala-Thr-Pro-. This sequence is typical for that around the active site residue of the subtilisins. From the determined sequences it is concluded that the fungal proteinase K is phylogenetically related to the bacterial subtilisins.

Amino Acid Sequence↗
PubMed1985

[Rhinorheomanometry in the self care of allergic patients].

Some pulmonary flow and pressure meters of low price and pocket shape are constructed particularly for self use and are prescripted by pulmologists. The use of these measuring instruments for rhinology was also attempted. None of the methodes also suggested supplied comparable results with rhinorheomanometry. If the already purchasable pulmonary measuring instrument INSPIRx is combined with a suitable sloping tube manometer we got results with a correlation coefficient of 0.9 in comparison to active anterior rhinorheomanometry. Moreover a completely new developed instrument of simple use is presented consisting only of cheap clinical one way articles. The measuring instrument suits the use in the allergologic consulting hour especially in patients away from hospital being under allergologic control because of repeated operations of the nasal sinus, allergic rhinitis, nasal polyposis or accompaniing bronchial asthma. By these patients the catarrh and therefore also the disabled nasal air passage are leading symptoms.

Airway Resistance↗
PubMed1985

[Importance of the general radiograph of the cervical spine in vertigo and pathologic proprioceptive cervical nystagmus].

The general roentgenogram of the cervical spine often shows manifold pathological alterations by patients without any clinical complaints. On the other hand, there are cervical vertigo and different symptoms caused by the cervical spine, its joints, muscles and ligaments without any X-ray manifestation. Nevertheless, some connections are assumed to exist between vertigo and alterations of the cervical spine an assumption supported especially by the frequently successful elimination of cervical troubles by chirotherapy. We compared the X-ray manifestations in patients complaining of vertigo with any and without any pathological proprioceptive cervical nystagmus provoked by examination according to Moser and revealed by electronystagmography. The extended posture of the cervical spine seems to point to a possible cause of vertigo. Likewise, some degenerative alterations seem to exercise a pathological effect, provoking cervical vertigo additionally if both effects are combined. Uncovertebral arthroses seem to have the same effect without occurring in combination with other effects. The general roentgenogram of the cervical spine in the sloping, lateral and anterior-posterior direction may consequently point to some possible causes of cervical vertigo.

Cervical Vertebrae↗
PubMed1985

[From the expert opinion case book: cervical nystagmus following injury of the occipital joint].

A case submitted for expertising is presented. After a fall on the occiput with a fracture of the occipital bone the patient had a pathological cervical nystagmus (type II according to Moser). The subjective complaints grew better in course of months. It is attempted to interpret the cause of the persistent proprioceptive cervical nystagmus. The disappearance of cervical vertigo is explained as being due to habituation.

Adult↗
PubMed1984

Characterization of lipoxygenase metabolites of arachidonic acid in cultured human skin fibroblasts.

Cultured human skin fibroblasts were incubated in the presence of [14C]arachidonic acid (50 microM; 1 m Ci/mmol) and the divalent cation ionophore A23187 at 37 degrees C for 60 min. The metabolites formed were extracted from the cell-free medium in diethyl ether, separated by thin layer chromatography and identified unequivocally by GC-MS. The distribution of the arachidonic acid metabolites as estimated from the recovered radioactivity showed as major product prostaglandin E2 (26%). Minor amounts of other prostaglandins, i.e., 6-oxo-prostaglandin F1 alpha (1%), prostaglandin F2 alpha (1%), prostaglandin D2 (0.5%) and prostaglandin A2 (1%) were also present. In addition to the prostaglandins, monohydroxy fatty acids (4.5%) were also detected. This fraction contained 33% 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT), 22% 11-hydroxy-5,8,11,14-eicosatetraenoic acid (11-HETE) and 31% 15-hydroxy-5,8,11,13-eicosatetraenoic acid (15-HETE). Lipid extracts of the cells did not show any detectable amount of the monohydroxy fatty acids, indicating that they are not incorporated metabolically in the cellular lipids. The monohydroxy fatty acids originate mainly from the exogenously added arachidonic acid as evidenced by the 2H/H ratio (30:1) from experiments with octadeuterated arachidonic acid [( 2H8]arachidonic acid). Indomethacin inhibited the formation of all prostaglandins, HHT and 11-HETE; moreover, eicosatetraynoic acid (also blocked the formation of 15-HETE. From these results, it can be concluded that in human skin fibroblasts prostaglandin E2 is the major product of the cycloxygenase pathway, while 15-HETE is the main lipoxygenase product.

Arachidonic Acid↗
PubMed1984

[Cervically-induced symptoms of the Klippel-Feil syndrome].

Klippel-Feil syndrome is a congenital deformity disease caused by disturbances of the growing together of the mesenchymal preliminary vertebrae which are mostly located in the regions of the cervical spine and shoulder. Short neck and wryneck (torticollis), as well as limited motion of the neck and reduced mobility of the cervical spine, are the most striking findings on clinical examination. Vertigo, disturbed sound conduction and perception, as well as combined loss of hearing, tinnitus and paralysis of the facial nerve can occur although otoscopic findings may be normal. Differential diagnosis is effected by means of the typical x-ray film of the cervical spine and the vertebrobasilar transition. Functional anomalies of the vertebral arteries are determined via x-ray angiography. Neuro-otological syndromes can be explained by congenital deformities of the middle ear, cochlea, peripheral vestibular organs and internal auditory canal; mainly, however, by a "vascular" cervical syndrome, which, in this particular case, explains the cochlea symptoms. Vertigo and dizziness can also be caused by a pathological irritation of cervical proprioceptive sensory organs through deformities of the skeleton.

Audiometry, Pure-Tone↗
PubMed1983

[Effect of the addition of DMSO and EDTA on the activity of formaldehyde and hydrogen peroxide against Bacillus cereus spores].

The question was investigated if DMSO in concentrations between 1 and 6% and 0.1% EDTA could improve the effect of the sporocidal disinfectants formaldehyde and hydrogen-peroxide. In suspension-tests with spores of Bac. cereus it was found, that the sporocidal activity of a 1.2 and 3% formaldehyde solution did not increase, in contrary it decreased significantly if EDTA or DMSO were present in the solution. The same effect could be found with 0.8-5% hydrogenperoxide in combination with the above mentioned substances. These results are not in agreement with the observations of other authors working with vegetative bacteria. It is supposed that DMSO rather reactivates injured spores than that it acts as a carrier for the respective disinfectant. This effect seems to mask a relatively faint increase of the permeability for the disinfectants. Concerning EDTA it could be possible, that it did not succeed in removing the Ca++ from the cortex, in contrary it seems, that it binds itself to the calciumdipicolinate thus stabilizing the spore structure.

Bacillus cereus↗
PubMed1983

[Changes in the quality of life after coronary revascularization].

The purpose of this study was to evaluate the change of quality of life after coronary revascularization. Out of 189 longterm survivors who underwent coronary revascularization between January 1979 and February 1980, 142 patients (134 men, 8 women) aged 36 to 71 agreed to cooperate in this study and to answer our questions. The questionnaire included 38 questions related to anginal pain, capacity for physical activity, employment, and psychological state. The change in the quality of life was assessed from the sum of changes in the variables. There was a significant improvement of angina in 82.4%, 81% were free of symptoms or in NYHA class I. 69.2% of those questioned claimed increased capacity for physical activity, and depression improved in 55.3%. The subjective improvement did not completely correlate with return to work, only 50.4% were working again after the operation. There was a significant relationship between reemployment and the period of unemployment before operation, as well as with the kind of employment. Quality of life was improved in 80.3% of the patients, unchanged in 10.5%, and poorer in 9.2%. From this study it may be concluded that coronary revascularization can improve the subjective feeling of well-being as well as physical symptoms.

Adult↗
PubMed1982

[A complication of peritoneojugular shunt for ascites: peritoneal migration of the shunt tubing].

A peritoneojugular shunt operation was done in a cirrhotic patient with ascites. The Le Veen valve functioned correctly for six months. The patient then experienced recurrence of ascites following an uncommon complication: migration of the shunt tubing into the peritoneal cavity. The tubing could no longer be felt in the cervical or thoracic regions. Plain roentgenograms of the abdomen showed that the shunt tubing was in the peritoneal cavity.

Ascites↗