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Biomedical subjects

B Meyer

Publications and source records attributed to B Meyer.

At least 307 records · Page 17Linked to original sources
PubMed1987

Use of photoretinoscopy as a screening technique in the assessment of anisometropia and significant refractive error in infants/toddlers/children and special populations.

The presence of significant refractive error and/or anisometropia can produce an irreversible decrease in visual function if not detected and treated at an early age. The general consensus is that the earlier a problem is detected, the easier the process of remediation. The authors have examined photoretinoscopy as a means of screening infant/toddlers and/or nonverbal persons for refractive anomalies. Fifty adults and fifty infants/toddlers/children were photographed and the estimated refractive error from review of the pictures was compared to the refractive error obtained from retinoscopy. The results indicate that photoretinoscopy is an effective screening procedure for the detection of significant refractive error and is extremely sensitive to anisometropia.

Adolescent↗
PubMed1987

Indications for multi- or single-channel cochlear implant for rehabilitation of total deafness.

Only totally deaf patients who do not experience improvement when using classical hearing aids are candidates for a cochlear implant. Preoperative assessment of potential benefits of a cochlear implant may improve selection of patients with pre- or postlingual total deafness, so that the most appropriate system can be implanted. The psychological status of potential candidates for implantation is particularly important because the results of postoperative re-education depends on motivation of the patient. The Round Window electrical stimulation test supplies us with important and measurable data (electrical threshold level, tone decay test). The duration of deafness, the degree of the deafness, and the cochlear tomodensitometry do not affect the decision to implant a cochlear device, (i.e., since the socialization level of the patient is a considerable factor). Preoperative assessment of the patient is very useful. As a result of our experience in 115 implanted cases suffering from pre- and postlingual deafness, we are now able to predict the good or bad results in our patients. Therefore, in patients who have many adverse factors for recovery, it seems to us more reasonable and cheaper to implant a single-channel system instead of a multichannel system, which must be reserved for patients who should do well. In very young children, the most appropriate system seems to be extra cochlear single-channel implant.

Cochlear Implants↗
PubMed1987

[Not Available].

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Education, Medical↗
PubMed1987

[Not Available].

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Germany↗
PubMed1987

[Values and limitations of embolization in cervical paragangliomas. Definition of a new diagnostic strategy. Apropos of 20 cases].

From 1966 to 1986, twenty cervical paragangliomas are treated by the authors: seven vagals and thirteen carotid one's. Seven patients out of these twenty underwent an embolisation during the pre-op arteriography. Studying the results, the authors show how much this embolisation increases the risk of a per-op carotid resection with by-pass, especially for the carotid localization. Dropping the embolisation, gives a chance for a new and, more acute diagnostic strategy, based on computerized tomography and digitalized arteriography. These exams should avoid the per-op discovery of these tumors in more than one half of the cases during an exploratory initial cervicotomy.

Adolescent↗
PubMed1987

[Use of the Reflotron system for laboratory diagnosis in swine and sheep].

The "Reflotron" system (Boehringer Mannheim) was compared with standard laboratory methods for determination of blood values, e.g. haemoglobin, glucose, urea, ASAT/GOT and GGT in pigs and sheep. Various different commercial control sera as well as blood and plasma samples from pigs and sheep were used for evaluation of its precision. The day-to-day precision of all parameters was satisfactory. The accuracy of the values was tested in 56(48) blood samples of healthy and sick pigs (sheep) by using standard substances (glucose, urea) and by comparing them with values measured by standard laboratory methods. There were systematic differences between "Reflotron" and other values in the glucose- and enzyme-values, which can be corrected with the help of conversion factors. In pigs, the enzyme GGT can not be determined accurately with the "Reflotron" system.

Animals↗
PubMed1987

Kinetics of piretanide tablets, penbutolol tablets and the fixed combination of both drugs in healthy male subjects after a single oral dose.

In an open-labelled cross-over study, ten healthy males received an oral dose of piretanide (6 mg tablet), penbutolol (40 mg film-coated tablet) or the fixed dose combination (film-coated tablet). Serum pharmacokinetics and 48 h urinary excretion of each drug were determined for the three dose regimens. The serum pharmacokinetics and excretion of penbutolol were unchanged in combination with piretanide. In combination with penbutolol the maximum serum concentration (Cmax) of piretanide was lowered by 40% (p less than 0.05) and time to reach Cmax delayed from 1.0 h to 1.6 h (p less than 0.05). However, areas under the serum concentration-time curves over 12 h and excretion of piretanide were unchanged, and its diuretic effect was undiminished. Thus the bioavailability of piretanide was unaffected by combination with penbutolol. The above changes in the pharmacokinetics of piretanide were explained entirely by differences in dissolution of the conventional and film-coated tablets. The drugs were safe and well tolerated.

Adult↗
PubMed1987

[Significance of the oral NBT-PABA test for the diagnosis of chronic pancreatitis].

The documentation of exocrine pancreatic insufficiency is important for the clinical diagnosis of chronic pancreatitis. The NBT-PABA test (Bentiromide test) depends on the cleavage peptide NBT-PABA by chymotrypsin and the quantitation of released PABA in serum or urine. The sensitivity of the oral NBT-PABA test is nearly as high as that of the much more demanding secretin-CCK test and the specificity is excellent as well. The NBT-PABA test is a simple and valuable aid for the clinical diagnosis and follow-up of patients with chronic pancreatitis.

4-Aminobenzoic Acid↗
PubMed1986

[Conformational analysis of the double pentasaccharide sequence of the "bisected" structure ov N-glycoproteins].

In the conformational analysis of the pentasaccharide alpha-D-Manp-(1----3)-[beta-D-GlcpNAc-(1----4)]-[alpha-D- Manp-(1----6)]-beta-D-Manp-(1----4)-D-GlcNAc, which represents the essential core structure within the bisected type of N-glycoproteins, n.m.r. experiments and GESA calculations indicated that a gg conformation is preferred for the (1----6)-glycosidic linkage. This is in contrast to the results obtained for the tetrasaccharide alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D- Manp-(1----4)- D-GlcNAc, which indicated that a gt conformation with the (1----6)-linked alpha-D-mannose group folded back is preferred. The conformations of the remaining glycosidic linkages in the tetra- and penta-saccharide are similar.

Carbohydrate Conformation↗
PubMed1986

[Multicenter randomized double-blind drug vs. placebo study of the treatment of tinnitus with Ginkgo biloba extract].

This important multicenter study of 103 tinnitus out-patients during a 13-month treatment period was carried out by ten E.N.T. specialists, using the double blind, drug versus placebo method. The results were conclusive as regards the effectiveness of Ginkgo biloba extract and made it possible to determine the prognostic value of different parameters. Of special importance among these parameters were site and periodicity of the disease. However, the Ginkgo biloba extract treatment improved the condition of all the tinnitus patients, irrespective of the prognostic factor.

Clinical Trials as Topic↗
PubMed1986

Heavy riboflavin synthase from Bacillus subtilis. Particle dimensions, crystal packing and molecular symmetry.

Heavy riboflavin synthase from Bacillus subtilis is an enzyme complex consisting of approximately three alpha-subunits (Mr 23.5 X 10(3)) and 60 beta-subunits (Mr 16 X 10(3)). The enzyme has been crystallized from phosphate buffer in a hexagonal crystal modification that belongs to space group P6(3)22. The asymmetric unit of the crystal cell contains ten beta-subunits. The structure of this unusual 10(6) Mr protein has been studied by small-angle X-ray scattering, electron microscopy of three-dimensional crystals, and crystallographic methods. The scattering curves can be interpreted in terms of a hollow sphere model with a ratio of inner and outer radius of 0.3:1. A diameter of 168 A was estimated from the scattering curves, in close agreement with electron microscopic studies. An aggregate with the stoichiometry beta 60, which was obtained by ligand-driven reaggregation of isolated beta-subunits, showed similar shape and dimensions, but a larger value for the ratio Ri/Ra. Electron micrographs of freeze-etched enzyme crystals showed approximately spherical molecules, which were arranged in hexagonal layers. The lattice constants found from the micrographs are in good agreement with the values derived from X-ray diffraction data. Rotation function calculations in Patterson space showed a set of peaks for 2-fold, 3-fold and 5-fold local rotation axes, accurately consistent with icosahedral symmetry and with the particle orientation A shown in the Appendix. The crystal packing can be described as follows: enzyme particles with icosahedral symmetry (point group 532) are located at points 32 of the hexagonal cell, corresponding to positions (0, 0, 0) and (0, 0, 1/2) on the 6-fold screw axes. From the data reported, it may be concluded that the enzyme structure can be described as an icosahedral capsid of 60 beta-subunits with the triangulation number T = 1. The alpha-subunits are located in the central core space of the capsid, but their spatial orientation is incompletely understood.

Bacillus subtilis↗
PubMed1986

Withdrawal of the long-acting beta blocker bopindolol is not associated with beta-adrenoceptor supersensitivity.

beta-Adrenoceptor sensitivity after abrupt withdrawal of long-term therapy (5-12 months) with bopindolol (1-2 mg/day), a long-acting beta-adrenoceptor blocking agent with intrinsic sympathomimetic activity, was assessed in five patients with uncomplicated essential hypertension. The chronotropic dose 25 of isoproterenol (CD 25), plasma concentrations of catecholamines, triiodothyronine and thyroxin, plasma renin activity and aldosterone, hemoglobin, hematocrit and oxyhemoglobin dissociation were measured on the last day of bopindolol administration and 1, 2, 3, 6, and 13 days after abrupt replacement by placebo tablets. The chronotropic dose 25 of isoproterenol (microgram/m2) was greater than 25.6 in all patients on the last day of bopindolol therapy. On day 1 in patients who had been taking 2 mg/day of bopindolol, CD 25 remained greater than 25.6 but fell to 12.1 in the one patient who had been taking 1 mg/day. On day 2, CD 25 was 10.19 +/- 2.97 and felt gradually to the lowest value of 3.76 +/- 1.19 on day 13. Throughout the study, plasma concentrations of catecholamines, triiodothyronine and thyroxin, and oxyhemoglobin dissociation remained unchanged. Plasma renin activity and plasma aldosterone, which were suppressed during bopindolol therapy, rose during placebo, coinciding with a fall in hemoglobin and hematocrit. No subjective symptoms of increased beta-adrenoceptor-mediated functions were reported by the patients throughout the whole study period. Therefore, hypersensitivity of beta-adrenoceptor-mediated responses was not demonstrated within the first 13 days after sudden withdrawal of bopindolol.

Adrenergic beta-Antagonists↗
PubMed1986

Persistent pulmonary granulomas after recovery from varicella pneumonia.

A 41-year-old man was found to have a miliary infiltrate on chest roentgenogram two months after recovery from varicella pneumonia. The patient remained in good health and there was no objective sign of pulmonary disease. The infiltrate showed no change in subsequent serial chest films, and after one year, open lung biopsy was performed. Histology revealed isolated necrotizing granulomas with a mononuclear infiltration and a fibrous capsule. We discuss the differential diagnosis of pulmonary granulomas and conclude that the roentgenographic and biopsy findings probably represent a persistent lesion after varicella pneumonia.

Adult↗
PubMed1986

Diagnosis of murine infections in relation to test methods employed.

Comparative investigations of Sendai virus, pneumonia virus of mice (PVM), mouse encephalomyelitis virus (mouse polio), minute virus of mice (MVM), and reovirus type 3 (Reo 3) infected murine colonies revealed a 30% higher incidence of positive sera when enzyme-linked immunosorbent assay (ELISA) was employed instead of hemagglutination inhibition (HI) tests. Equivalent sensitivity as in the ELISA was obtained when the same sera were investigated by indirect immunofluorescence (IF) tests. The virus purification techniques described resulted in highly suitable antigens for all indirect ELISA established. Since IIF requires no purified antigens, this test is recommended as an alternative to ELISA as well as to HI and complement fixation (CF) tests for laboratories lacking the necessary equipment for high speed centrifugation. A high incidence of false positive HI reactions was found particularly in Reo 3 routine serology. An updated survey of seromonitoring showed that European murine colonies appeared to be infected far less with Reo 3 if ELISA or IIF tests were employed. During 1982-1984, only 13% of the mouse colonies screened possessed Reo 3 positive sera whereas no natural Reo 3 infection was found in rat colonies. Mouse hepatitis virus (MHV) and the coronaviruses of rats exhibited the highest incidence in murine colonies. A total of 60% of mouse and 41% of rat colonies were found to be infected by these viruses. In comparison with earlier serological surveys, the relative incidence of other murine infections was similar. Antibodies against Bacillus piliformis (Tyzzer's disease) were detected by the IIF test in 41% of the rat colonies screened.

Animals↗