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Biomedical subjects

M Becker

Publications and source records attributed to M Becker.

At least 199 records · Page 11Linked to original sources
PubMed1995

Biosynthesis of (1,3)(1,4)-beta-glucan and (1,3)-beta-glucan in barley (Hordeum vulgare L.). Properties of the membrane-bound glucan synthases.

Mixed membrane preparations from the coleoptiles and first leaves of young barley (Hordeum vulgare L. cv. Triumph) plants catalysed the synthesis of 55% methanol-insoluble labelled material from UDP-[U-14C]glucose, the main components of which were identified as (1,3)(1,4)-beta- and (1,3)-beta-D-glucans. The membrane preparations also catalysed the transformation of UDP-glucose into labelled low-molecular-weight products, mainly glucose (by phosphatase action), glucose-1-phosphate (by phosphodiesterase action) and glyco(phospho)lipids (by glycosyltransferase action). The formation of (1,3)(1,4)-beta-glucans, (1,3)-beta-glucans, and the other reactions competing for UDP-glucose, were monitored simultaneously and quantitatively by a novel procedure based on enzymatic analysis, thin-layer chromatography and digital autoradiography. Thus it was possible (i) to optimise conditions to obtain (1,3)(1,4)-beta-glucan synthesis or (1,3)-beta-glucan synthesis in isolation, and (ii) to study the influence of temperature, pH, cofactors, substrate concentration etc. on the (1,3)(1,4)- and (1,3)-beta-glucan synthesis reactions even when both occurred together. The synthesis of both beta-glucans was optimal at 20 degrees C. In Tris-HCl buffer, the pH optima for (1,3)(1,4)-beta-glucan synthesis and (1,3)-beta-glucan synthesis were pH 8.5 and pH 7.0, respectively. Both glucan-synthesis reactions required Mg2+: (1,3)-beta-glucan synthesis was optimal at 2 mM, whereas (1,3)(1,4)-beta-glucan synthesis continued to increase up to 200 mM Mg2+, when the ion was supplied as the sulphate. (1,3)-beta-Glucan synthesis was Ca2+ dependent and this dependence could be abolished by proteinase treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Conformation↗
PubMed1995

Unimanual motor learning impaired by frontomedial and insular lesions in man.

We correlated impaired unimanual motor learning with the lesion site in 53 patients with chronic lesions predominantly of the frontal lobe. The lesions were assessed using computed tomography (CT), then transferred to standard templates of nine slices parallel to the canthomeatal plane and digitized with a raster matrix of 3 mm by 3 mm width. The learning task was to track a moving target on a computer screen with a dot guided by the preferred hand, while the horizontal coupling between hand movement and screen was inverted. The mean tracking error was recorded over eight successive trials of 80s duration. If the mean error of the last three trials was not lower than that of the first three trials, impaired motor learning was assumed. We correlated performance and lesion with a contingency table analysis for each raster element. Impaired motor learning was associated with a lesion within the supplementary motor area and adjacent anterior cingulate, and within the anterior insular region. Our results indicate that these regions are critical for motor learning and functional plasticity in man. Our data support activation patterns obtained with positron emission tomography.

Adolescent↗
PubMed1995

Plasma cell granuloma of the supraglottic larynx.

The occurrence of plasma cell granuloma of the larynx appears to be unusual. Review of the literature revealed only two previously reported cases. We present an additional case of plasma cell granuloma of the larynx. The diagnosis was made by histological and immunohistochemical examinations. The tumour was successfully treated by radiation therapy.

Granuloma, Plasma Cell↗
PubMed1995

Preservation of peripheral nerve grafts: a comparison of normal saline, HTK organ preservation solution, and DMEM Schwann cell culture medium.

The regeneration of peripheral nerve grafts was evaluated in a rat model, after pretreating the grafts with Schwann cell culture medium, HTK organ preservation solution, and normal saline, under cold ischemic conditions for different time periods. Following orthotopic replantation of the grafts into donor animals, the quality of regeneration was assessed after 6 weeks, compared to positive controls (autologous transplantation) and negative controls (acellular grafts). The regenerative quality in the Schwann cell culture groups with ischemic periods of 32 and 72 hr was comparable to normal controls. Significantly minor regeneration was detected in specimens undergoing 14 and 120 hr of ischemia in the Schwann cell culture medium and in the HTK and normal saline groups, regardless of ischemic time. Among the conclusions was that controlled proliferation of Schwann cells seems to be a basic principle for preservation of peripheral nerve grafts.

Animals↗
PubMed1995

[Kinetic fundus controlled perimetry with the scanning laser ophthalmoscope].

BACKGROUND: The detection of circumscribed visual field defects due to pathologic macular findings may be difficult even when modern conventional perimetry procedures are used. Using conventional clinical methods there exists no reliable correlation between morphology and function for follow-up and documentation. The Laser Scanning Ophthalmoscope enables a fundus-based examination and therefore allows exact comparison between morphologic appearance and corresponding function. PATIENTS AND METHODS: 50 eyes with pathologic macular findings were examined using a newly developed kinetic perimetry method based on the Scanning Laser Ophthalmoscope. The results were compared to those obtained with other clinical examinations such as Goldmann or Octopus visual field and Amsler-chart. RESULTS: Fundus-based examination with the SLO is preferable for detection especially when small pathologic findings at the posterior pole like macular holes or small serous detachments are combined with reduced stability of fixation. The detection of sharp borders of the scotomas is much better than with conventional perimetry. CONCLUSION: The Scanning Laser Ophthalmoscope allows several different types of fundus-based examinations. Concerning kinetic perimetry we were able to find the borders of scotomas within very short examination times. This method therefore is of valuable help in patients with circumscribed scotomas at the posterior pole combined with deterioration of the stability of fixation and allows documentation for follow-up and further comparison with other clinical findings.

Adult↗
PubMed1995

Characterization of kinectin, a kinesin-binding protein: primary sequence and N-terminal topogenic signal analysis.

Kinectin is a kinesin-binding protein (Toyoshima et al., 1992) that is required for kinesin-based motility (Kumar et al., 1995). A kinectin cDNA clone containing a 4.7-kilobase insert was isolated from an embryonic chick brain cDNA library by immunoscreening with a panel of monoclonal antibodies. The cDNA contained an open reading frame of 1364 amino acids encoding a protein of 156 kDa. A bacterially expressed product of the full length cDNA bound purified kinesin. Transient expression in CV-1 cells gave an endoplasmic reticulum distribution that depended upon the N-terminal domain. Analysis of the predicted amino acid sequence indicated a highly hydrophobic near N-terminal stretch of 28 amino acids and a large portion (326-1248) of predicted alpha helical coiled coils. The 30-kDa fragment containing the N-terminal hydrophobic region was produced by cell-free in vitro translation and found to assemble with canine pancreas rough microsomes. Cleavage of the N terminus was not observed confirming its role as a potential transmembrane domain. Thus, the kinectin cDNA encodes a cytoplasmic-oriented integral membrane protein that binds kinesin and is likely to be a coiled-coil dimer.

Amino Acid Sequence↗
PubMed1995

Neoplastic invasion of the laryngeal cartilage: comparison of MR imaging and CT with histopathologic correlation.

PURPOSE: To compare the usefulness of computed tomography (CT) and gadolinium-enhanced magnetic resonance (MR) imaging in the detection of neoplastic invasion of laryngeal cartilage. MATERIALS AND METHODS: In a prospective study, 53 patients with carcinoma of the larynx or piriform sinus underwent CT and MR imaging before total or partial laryngectomy. The findings at imaging and pathologic examination were compared. RESULTS: At histologic examination, neoplastic invasion of cartilage was present in 34 patients and absent in 19. MR imaging was more sensitive than CT (89% vs 66%; P = .001). Inflammatory changes and fibrosis, however, were indistinguishable from tumor on MR images, resulting in overestimation of neoplastic invasion in a large number of patients. Therefore, MR imaging was less specific than CT (84% vs 94%; P = .004). CONCLUSION: MR imaging is more sensitive than CT in detecting neoplastic invasion of cartilage, but the inability to differentiate between nonneoplastic inflammatory changes and tumor with MR imaging leads to overestimation of neoplastic invasion.

Carcinoma, Squamous Cell↗
PubMed1995

Quality-of-life instruments for severe chronic mental illness. Implications for pharmacotherapy.

The care of persons with severe chronic mental illness is one of the most pervasive and neglected public health problems in the US. Increasingly, researchers are focusing on the effectiveness of care and quality of life in these patients. This article reviews the status of quality-of-life (QOL) research in mental health published until 1993. It describes conceptual and methodological approaches, reviews QOL instruments developed for persons with severe chronic mental illness, and discusses the implications for pharmacotherapy. Consistent methods, definitions and models must be developed to make QOL research more applicable to the evaluation of pharmaceuticals. Standardisation of approach is necessary to facilitate meta-analyses and to increase our understanding of how pharmacotherapy can improve quality of life for persons with severe chronic mental illness. QOL data cannot stand alone. Its use is limited by the reality that psychopathology affects quality of life, and quality of life affects psychopathology. For the foreseeable future, evaluation of pharmacotherapy in severe chronic mental illness will require combined measurement of quality of life and psychopathological symptoms.

Chronic Disease↗
PubMed1995

[In vitro studies of the specifications for methodological and technical equipment requirements of endoscopic infrared diaphanoscopy].

Endoscopic infrared diaphanoscopy is a method of improving orientation in the nasal cavity during endoscopy-controlled endonasal surgery. The transillumination is expected to facilitate the localisation of the natural passageways between the paranasal sinuses and the nasal cavity during endoscopic procedures. The present study specifies the necessary conditions on the basis of in vitro examinations using an animal model (sheep) and an anatomical preparation of half of the human head. The questions as to what paranasal sinus is at all accessible to diaphanoscopy, whether the method actually enables the connecting pathways between an individual sinus and the nasal cavity to be identified, and what technical demands need to be met, are considered and answered.

Animals↗
PubMed1995

Stability of fixation: results of fundus-controlled examination using the scanning laser ophthalmoscope.

We evaluated the stability of fixation in 38 healthy eyes (N), 30 eyes with macular degeneration (AMD) and 20 eyes with juvenile macular dystrophy (JMD) during our newly developed automated full-threshold static perimetry using the scanning laser ophthalmoscope (SLO). The point of fixation was recorded for each stimulus presentation. After the examination, the mean fixation point (MFP) as well as the standard deviation from the MFP, the examination time, and the reaction time were evaluated. Healthy eyes did not show a mean SD of more than 0.7 degree from the center of gravity of fixation with one exception. There was only poor correlation between age and deviation from the MFP (r = 0.09 for N; r = 0.18 for AMD; and r = 0.18 for JMD), whereas the correlation between visual acuity (VA) and deviation from the MFP was slightly better (r = 0.22 for N; r = 0.34 for AMD; and r = 0.52; P < 0.02 for JMD). Eyes with functional impairment mostly showed instable fixation (deviation, > 3 degrees), which was observed even in two patients with only slightly diminished VA of 20/25. However, stable fixation was observed in isolated cases even when VA was reduced to 20/100. The deviation of fixation was more pronounced horizontally than vertically in normals (0.40 degree:0.31 degree) and in patients suffering from AMD (0.88 degree:0.68 degree), whereas eyes with macular dystrophy did not show this phenomenon (0.82 degree:0.82 degree). The results demonstrate that there is the possibility of stable fixation even in eyes with a decrease in VA due to morphological changes in the macula.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Necrotizing fasciitis of soft tissues of the face and neck].

Three cases of cervical necrotizing fasciitis are presented. One case was odontogenic in origin and two were due to pharyngeal infectious. Bacteria cultured represented multiple bacterial species. Airway control was necessary early, as was wide surgical exploration of the fascial spaces of the neck with re-exploration as necessary. Intensive medical support was crucial to prevent or treat complications. Cervical necrotizing fasciitis has an overall mortality rate of 30 per cent at the University of Bern.

Aged↗
PubMed1995

Comparative survival, quality of life and cost-effectiveness of intensive therapy with autologous blood cell transplantation or conventional chemotherapy in multiple myeloma.

We retrospectively compared survival time, quality of life, and the therapy costs in 37 patients suffering from newly diagnosed multiple myeloma (MM), divided into 3 groups. Twelve patients with grade III MM, according to the classification of Durie-Salmon, all with widespread lytic lesions (group I), underwent a two-phase intensive therapy. They first received high-dose melphalan (HDM), both as tumor-reducing and blood cell (BC)-mobilizing chemotherapy, subsequently followed by BC transplantation. Group II comprising 10 patients, also with grade III MM and with characteristics similar to those of group I, were treated with conventional polychemotherapy. Finally, group III enrolled 15 patients with lower grade disease (grade II) who were also treated with conventional chemotherapy. The median overall survival time and the quality of life index were significantly lower in group II than in group I (P = 0.0013 and < 0.001 respectively). Although the overall survival time of group III (43 months) was similar to that of group I, its quality of life index was also significantly lower (P < 0.05). However, the total therapy costs of group I were globally higher than those of the 2 other groups, but when absolute cost-effectiveness as well as qualitative cost-effectiveness (corrected for quality of life) were analyzed, the costs per week of life gained of group I compared extremely favorably with those of group II and, to a lower degree, of group III. Intensive therapy therefore seems capable of substantially improving the survival time for high-risk MM patients with satisfactory quality of life and at a reasonable cost.

Adult↗
PubMed1995

Focal inflammation of the corpus cavernosum in a diabetic man due to acute occlusion of the cavernous artery.

Inflammation of the penile corpus cavernosum is an unusual condition most often associated with an infectious process. We report on a diabetic man with localized inflammation of the corpus cavernosum resulting from acute occlusion of the cavernous artery. Diagnosis was made by exclusion and ultimately confirmed by penile angiography. Conservative measures led to resolution of this process.

Acute Disease↗