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Biomedical subjects

G Meyer

Publications and source records attributed to G Meyer.

At least 199 records · Page 11Linked to original sources
PubMed1996

Bronchiolitis obliterans organizing pneumonia associated with chlamydial infection.

A 70 year old man presented with symptoms and laboratory findings suggestive of chlamydial pneumonia. Despite adequate antibiotic therapy, his condition did not improve and transbronchial biopsies disclosed a typical feature of bronchiolitis obliterans organizing pneumonia (BOOP). After initiation of corticosteroid therapy, there were marked clinical and radiographic improvements. This report demonstrates that chlamydial infection may be associated with BOOP.

Aged↗
PubMed1996

Effect of frusemide on Cl- channel in rat peritoneal mast cells.

Frusemide can be used as an antiasthma drug and appears to inhibit the release (conditioned by activation of Cl- channels) of mast cell proinflammatory mediators. We studied the cause of the effects of frusemide, checking its action on Cl- channels. The patch-clamp technique was used to study single-channel currents, and differences in electrical potential of the cellular membrane of rat peritoneal mast cells were measured. In inside-out configuration, outwardly-rectifying Cl- channels were identified whose conductance was 2.4/1.7 pS at positive and negative voltages. In cell-attached configuration, the open probability (Po) of the channel increased with depolarization or with the presence of cyclic adenosine monophosphate (cAMP) in the incubation medium. Po increased with a rise of cytoplasmic free calcium concentration [Ca2+] and was inhibited by 5-nitro-2-(3-phenylpropylamino)-benzoate (NPPB) and by 4-4'-diisothiocyanatoostilbene-2-2'-disulphonic acid (DIDS). These channels seem to be the main cause of mast cell Cl- conductance. Frusemide (10(-5) and 10(-3) M) did not affect Cl- channel activity when using excised patches. In cell-attached configuration experiments, the presence of frusemide (from 10(-5) to 10(-3) M) in the cell incubation medium, increasingly reduced Po (median inhibitory concentration (IC50) = 4.3 x 10(-7) M). In similar conditions, bumetanide also inhibited Po (IC50 = 5.7 x 10(-3) M). The results of this study suggest that frusemide can inhibit mast cell Cl- channels only via an indirect mechanisms, which probably involves an inhibition of a Na(+)-K(+)-2Cl- symport.

Animals↗
PubMed1996

[Liver resection with the water jet: conventional and laparoscopic surgery].

In a prospective study 60 patients underwent liver resection. Two different resection techniques, ultrasonic aspirator (CUSA, n = 30) and Jet-Cutter (n = 30), were compared, Speed of resection, blood loss, transfusion rate, liver hilus clamping time and tissue damage were evaluated on the basis of the area of transsected liver. Liver resection with the Jet-Cutter was significantly faster with a resection time of 0.35 min/cm2 in comparison to the CUSA (0.77 min/cm2, p < 0.001) and associated with less blood loss of 18.4 ml/cm2 (p < 0.05) than the CUSA technique (34.4 ml/cm2). Tissue damage in respect to levels of transaminases SGOT and SGPT was comparable with both techniques. The Jet-Cutter is a promising new instrument in liver surgery, and challenged by these results we used the Jet-Cutter in 7 patients performing laparoscopic liver resections.

Adult↗
PubMed1996

[Are high risk patients candidates for minimally invasive surgery with CO2 pneumoperitoneum? Viewpoint from anesthesiology].

As laparoscopic techniques show definite advantages in terms of pain and postoperative pulmonary function, high-risk patients especially benefit from such procedures. Pathophysiological changes caused by the pneumoperitoneum can be managed with invasive monitoring and resulting therapy. The increase in systemic vascular resistance with reduction in cardiac output can be kept to a minimum using low intraabdominal pressures (8-10 mmHg) under adequate muscular relaxation. Additional peripheral vasodilators and positive inotropic medication may be necessary. As the adverse hemodynamic effects end almost instantaneously with the reduction of the intraabdominal pressure, it is allways possible to revert to an open procedure after a laparoscopic try. If ventilation can not be increased adequately to maintain isocapnia in a patient suffering from pulmonary disease, the resulting increase in paCO2 will usually be moderate. In some instances it may be necessary to prolong artificial ventilation postoperatively, until isocapnia is reached with minuteventilation as at the beginning of anaesthesia.

Hemodynamics↗
PubMed1996

[Alcohol in Munich secondary school students--a study for dissemination of experiences, knowledge, attitude and behavior].

The Munich Community Health Service (Medical School-Service Department) conducted an alcohol prevention project in ten public secondary schools. The 423 pupils (11-17 years of age) filled in a questionnaire on alcohol and discussed it afterwards under the guidance of a school physician and a teacher using guideline information. The results of the survey are presented in this paper. Additionally, suggestions for transferring the results to conceptualize and carry out preventive measures are made. The results indicate that the first experience with alcohol occurred early in life. One-fifth of the sample had already tried alcohol at the age of six. Immediate effects of alcohol (e.g. state of drunkenness) were experienced by 35.7 percent of the sample group. Kiosks, shops, and beverage stores were named most frequently as sources for alcohol. The sources of social support varied with respect to sex and age. With increasing age of the children, parents were contacted less frequently whereas the role of peers increased. The present results supply possible paths of action for the development of successful prevention strategies, e.g. by pointing out the early age of onset as well as specific sources of alcohol acquisition.

Adolescent↗
PubMed1995

Regulation of L-valine absorption by opioids interacting with mu-receptors in rabbit ileum.

In intact tissue, [D-Ala2,MePhe4,Gly-ol5]enkephalin (10(-5) M; mu-ligand), diminished short-circuit current (Isc) and increased water, Na+ and Cl- net fluxes in vitro under open circuit conditions; it also inhibited L-valine absorption and L-valine-dependent variations of short-circuit current (delta Isc,val). Naloxone (10(-6) M) antagonized these effects. In the absence of the muscularis and myenteric plexus this enkephalin or morphine (mu-ligand) reduced Isc and delta Isc,val. These enkephalin effects occurred at different times. Different concentrations of enkephalin were tested for their effects on delta Isc,val. [D-Ala2,D-Leu5]enkephalin (mainly a delta-ligand) significantly decreased Isc but not delta Isc,val. The reduction of L-valine absorption does not depend on the effects on basal ion transport. Interaction of opioids with mu-receptors located in the submucosal plexus and/or in the epithelial cell accounts for this reduction. This enkephalin effect seems to be at least partially under the control of the myenteric plexus.

Analgesics↗
PubMed1995

Functional MRI evidence for adult motor cortex plasticity during motor skill learning.

Performance of complex motor tasks, such as rapid sequences of finger movements, can be improved in terms of speed and accuracy over several weeks by daily practice sessions. This improvement does not generalize to a matched sequence of identical component movements, nor to the contralateral hand. Here we report a study of the neural changes underlying this learning using functional magnetic resonance imaging (MRI) of local blood oxygenation level-dependent (BOLD) signals evoked in primary motor cortex (M1). Before training, a comparable extent of M1 was activated by both sequences. However, two ordering effects were observed: repeating a sequence within a brief time window initially resulted in a smaller area of activation (habituation), but later in larger area of activation (enhancement), suggesting a switch in M1 processing mode within the first session (fast learning). By week 4 of training, concurrent with asymptotic performance, the extent of cortex activated by the practised sequence enlarged compared with the unpractised sequence, irrespective of order (slow learning). These changes persisted for several months. The results suggest a slowly evolving, long-term, experience-dependent reorganization of the adult M1, which may underlie the acquisition and retention of the motor skill.

Adult↗
PubMed1995

Different techniques of laparoscopic end-to-end small-bowel anastomoses.

The aim of the study was to prove that laparoscopic stapling devices can be used to create a bowel anastomosis. Three groups with n = 6 pigs each were subjected to different techniques of small-bowel anastomoses. In groups I and II anastomosing of the bowel ends was carried out with singly placed staples using a hernia stapler. (Group I: Two-thirds of the circumference became inverted and one-third everted. Group II circumferentially everted). In group III triangular everted anastomoses were produced using a linear noncutting stapler. All animals survived the observation period of 14 days and were postmortally examined. Average construction time was 59 min for groups I and III and 47 min for group II. Average diameters were 14 mm, 16 mm, and 18 mm for groups I, II, and III, respectively. There were no significant differences between the techniques concerning the stability of the anastomoses as expressed by bursting pressures. There were two stenoses in group I animals caused by electrocautery during preparation of the bowel ends prior to anastomosing. Anastomotic insufficiencies or fistulas were not observed clinically or with Gastrografin studies. We conclude that anastomoses in the pig can laparoscopically be constructed by employing singly placed staples as well as a linear stapler. Further investigations of these techniques on large bowel and human specimens are required prior to their clinical use in humans.

Anastomosis, Surgical↗
PubMed1995

Laparoscopic liver resection with the water-jet dissector.

Laparoscopic liver resection requires careful patient selection. Tumor size and location have a major influence on the feasibility of a laparoscopic operation. Isolation and ligation of blood vessels and bile ducts after selective liver dissection by suitable techniques are important for visual control of the operating field. Since the Jet-Cutter has proven to give excellent clinical results in conventional liver surgery, we carried out laparoscopic liver resections with the Jet-Cutter in six patients. Five tumors were located in the left liver lobe; the fifth was in segment 6. There were no intra- or postoperative complications. The patients were discharged from the hospital after a mean of 5.4 +/- 2.1 days.

Adult↗
PubMed1995

Age-dependent induction of pyruvate, orthophosphate dikinase in Mesembryanthemum crystallinum L.

A full-length transcript for pyruvate, orthophosphate dikinase (PPDK; EC 2.7.9.1), has been characterized from Mesembryanthemum crystallinum. Under salt stress or with increasing age, this plant shows a transition from C3 to Crassulacean acid metabolism (CAM). The PPDK plays a central role in gluconeogenesis during the light phase of CAM. The transcript is 3165 bases in length with a single open reading frame of 2739 nucleotides specifying a protein of molecular mass 103098, including a transit peptide of mass 7902 for chloroplast import. The protein shares 44-77% sequence identity with PPDK from C4-plants and microorganisms. Known functional and regulatory amino acids are conserved. Southern-type hybridizations indicated one copy or very few closely related copies of the gene per haploid genome. We investigated the induction of PPDK at the mRNA and protein levels, using the well characterized induction of a CAM-form of phosphoenol pyruvate carboxylase (PEPCase) as internal standard. During wilting of excised leaves PEPCase mRNA amounts increased strongly within 8 h. Under these conditions amounts of PPDK mRNA remained constant. Re-hydrating leaves from previously stressed plants led to a decrease in PEPCase and PPDK mRNA amounts. During salt stress, no correlation between PEPCase and PPDK was observed. Analysis of plants of different ages indicated that, even in well-watered plants, PPDK-specific protein and mRNA increased when the plants reached a certain age. In old plants, salt stress failed to further increase PPDK mRNA or protein levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1995

Surgical treatment of tumor metastases: general considerations and results.

The prerequisite for a curative resection of metastases is their restriction to the key organs, the liver and lungs, in the sense of a limited dissemination. For long-term prognosis, the type of primary tumor as well as the radical resection of lung and liver metastases is essential. To improve the process of surgical indication and therapy of tumors, clear definitions for the terms "tumor recurrence" and "metastases" have been agreed upon. Research and clinical investigation have led to a better understanding of tumor-regulating factors, some of which are briefly described: Metastasis promoting factors include the lack of E-cadherin, which leads to a local penetration of basal membranes by tumor cells; CD44 seems to play an important role in cell-cell and cell-matrix interactions, apparently increasing the metastatic potential of tumors and reducing the long-term survival of patients. High levels of urokinase in primary tumors are also associated with a poorer prognosis, as well as plasminogen inactivator inhibitor PAI II, which plays a crucial role in tumor growth. Positive findings in bone marrow aspirates of patients with different malignancies, stained for cytokeratin 18, either are associated with higher recurrence rates in colon and breast cancer or can be correlated to the prognosis of patients with gastric cancer. Technical aspects of surgery for hepatic, pulmonary and skeletal metastases are presented and discussed with respect to curative and palliative indications.

Bone Neoplasms↗
PubMed1995

Technetium-99m mercaptoacetyltriglycine clearance: reference values for infants and children.

Six hundred and thirty-nine clearance studies performed in children aged 7 days to 19 years utilizing technetium-99m mercaptoacetyltriglycine (MAG 3) were retrospectively analysed. Standardized conditions for the investigation included: parenteral hydration (60 ml/hxm2 body surface) in addition to normal oral fluid intake, weight-related dose of 99mTc-MAG 3 (1 MBq/kg body weight, minimum 15 MBq) and calculation of clearance according to Bubeck et al. Of the 513 children, 169 included in this analysis could be classified as "normal" with regard to their renal function. Normal kidney function was judged by the following criteria: normal GFR for age, normal tubular function (absence of proteinuria and glucosuria), normal renal parenchyma (on ultrasonography, MAG 3 scan and intravenous pyelography), absence of significant obstruction and gross reflux (>grade I), no single kidney and no difference in split renal function >20%. Results showed increasing MAG 3 clearance values for infants during the first months of life, reaching the normal range for older children and adults between 7 and 12 months.

Adolescent↗
PubMed1995

The nucleotide sequence of the fusion protein gene of the peste des petits ruminants virus: the long untranslated region in the 5'-end of the F-protein gene of morbilliviruses seems to be specific to each virus.

cDNA corresponding to the fusion protein (F) gene of the vaccine strain of peste des petits ruminants virus (PPRV) was cloned and sequenced. The gene was 2321 nucleotides long excluding the poly(A) tail. As with other morbilliviruses, it had a long G/C rich stretch of about 525 nucleotides. There was no start codon before position 489 in the nucleotide sequence. From the 489th nucleotide to the 549th nucleotide, there were 4 ATG codons, two of which were in frame. The fourth ATG codon was in the best context to act as a start codon for encoding a protein which will be composed of 546 amino acids with a predicted molecular weight 59,310 Da. The comparison of the nucleic acid sequences of different morbillivirus F-protein genes revealed that the 5'-end sequence of the mRNA is specific to each virus. This sequence contains a long stretch of nucleotides rich in G/C content. When protein sequences were compared, it appears that, during evolution, substitutions in amino acid occurred in the F-protein of morbilliviruses such that the structure required for the fusion activity remains unchanged. These substitutions appear to have only occurred in the leader and the membrane anchor sequences, probably as an adaptation of the protein to the host cell.

Amino Acid Sequence↗
PubMed1995

Identification of a gephyrin binding motif on the glycine receptor beta subunit.

The tubulin-binding protein gephyrin copurifies with the inhibitory glycine receptor (GlyR) and is essential for its postsynaptic localization. Here we have analyzed the interaction between the GlyR and recombinant gephyrin and identified a gephyrin binding site in the cytoplasmic loop between the third and fourth transmembrane segments of the beta subunit. GlyR alpha subunits and GABAA receptor proteins failed to bind recombinant gephyrin. However, insertion of an 18 residue segment of the GlyR beta subunit into the GABAA receptor beta 1 subunit conferred gephyrin binding both in an overlay assay and in transfected mammalian cells. These results indicate that beta subunit expression is essential for the formation of a postsynaptic GlyR matrix.

Amino Acid Sequence↗