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Biomedical subjects

G Meyer

Publications and source records attributed to G Meyer.

At least 235 records · Page 13Linked to original sources
PubMed1994

Extracorporeal shock-wave lithotripsy prior to laparoscopic cholecystectomy. Does it make sense?

The extraction of large gallstones in laparoscopic cholecystectomy either requires the enlargement of one of the incisions or intraoperative lithotripsy. Preoperative extracorporeal shock-wave lithotripsy (ESWL) might theoretically solve the problem and facilitate the extraction of the gallbladder. Ten patients with at least one gallstone larger than 20 mm in diameter underwent ESWL treatment within 24 h prior to laparoscopic surgery. Complete pulverization of stones was achieved in one patient. Fragmentation into pieces smaller than 10 mm could be observed in another three cases. Additional mechanical fragmentation employing forceps was necessary in seven and an enlargement of the incision in five of the 10 patients. Compared to a matched group of 10 control patients with gallstones of corresponding size receiving mechanical lithotripsy, the ESWL did not show an advantage, but rather an increase in costs. It therefore cannot be recommended.

Adult↗
PubMed1994

Laparoscopic deroofing of post-transplant lymphoceles.

Lymphocele is a most common surgical complication following renal transplantation. The indication for treatment is given when the lymphocele becomes symptomatic. We succeeded in laparoscopically deroofing large lymphoceles in nine patients that were causing ureter compression in eight and ipsilateral leg edema in six cases. The postoperative course was uneventful, and the surgery-related hospitalization did not exceed 7 days. Severe adhesions and a thick lymphocele wall, which made preparation difficult, resulted in the transection of the transplant ureter in one case. Techniques and prerequisites that would help to avoid this type of complication are discussed. According to CT scan or sonography, there was no recurrence in any of the patients after a mean follow-up of 11 months. This technique seems to be superior to other methods of treatment because not only is a cure obtained with a single intervention, but there is also a low risk of infection and a short hospitalization.

Adult↗
PubMed1994

Structure, diversity and synaptic localization of inhibitory glycine receptors.

The inhibitory glycine receptor (GlyR) mediates postsynaptic inhibition in spinal cord, brain stem and other regions of the vertebrate central nervous system. Biochemical and molecular approaches have identified different developmentally and regionally regulated GlyR isoforms that result from the differential expression of at least four genes coding for different variants of the ligand-binding alpha subunit. Molecular studies have allowed identification of GlyR subunit domains implicated in ligand binding, channel formation and receptor assembly. At the postsynaptic membrane, the GlyR colocalizes with a 93-kDa tubulin-binding peripheral membrane protein, gephyrin. Antisense inhibition of gephyrin expression prevents GlyR accumulation at postsynaptic membrane specialization. Thus, gephyrin is essential for postsynaptic receptor topology.

Animals↗
PubMed1994

[The value of mini-tracheotomy as a new interventional technique in treatment of postoperative tracheobronchial retention of secretions. Results of a prospective study of 152 surgical intensive care patients].

OBJECTIVE: Since minitracheotomy has been established in 1984 for prophylaxis and therapy of postoperative sputum retention, numerous publications represent technical descriptions, case reports or empirical results, but only few specific facts related to this method have been investigated. In this study we review the efficiency, complications and late follow-up results of minitracheotomy in a department of general surgery. DESIGN: Between 1987 and 1991 we prospectively included 152 intensive-care patients who received minitracheotomy. The average follow-up was 24.2 +/- 6.1 (4-50) months. RESULTS: Endotracheal secretion could be sucked off significantly more often after mini-tracheotomy. The rate of endotracheal suction increased from 5.9 +/- 4.5/d to 18.4 +/- 6.1/d (p < or = 0.01). The pulmonary gas exchange improved at the same time. PaO2 level of 78.9 +/- 9.9 mmHg that decreased to critical values of 60.7 +/- 8.9 mmHg, rose after minitracheotomy above the original levels. Although the PaCO2 level remained constant, a compensatory hyperventilation with a rate of 27.3 +/- 6.9/min was normalised by minitracheotomy. Furthermore, the various methods of minitracheotomy were opposed in this study. In the group of minitracheotomy by cricothyroideal stab incision (n = 55) we recorded 5.4% serious complications. In contrast minitracheotomy by the Seldinger technique (n = 87) could be accomplished without any disturbance. CONCLUSION: Minitracheotomy seems to be an effective and safe treatment for therapy and prophylaxis of postoperative complications due to tracheobronchial sputum retention in critically ill patients. Manipulation was simplified and rendered more safe by the technique of transcutaneous bouginage.

Adult↗
PubMed1994

Effectiveness and costs of veterans affairs hypertension clinics.

The effectiveness and costs of care for hypertension are examined in a stratified random sample of 3,087 patients from a network of 32 Veterans Affairs Hypertension Screening and Treatment Clinics (HSTP). During 2.5 years of follow-up, 66% and 88% of patients, respectively, had mean diastolic blood pressure (DBP) levels of 90 or 95 mm Hg or less; 73% remained fully in care; and the mean cost of ambulatory care per patient-year was $647 in 1989 dollars. Higher follow-up DBP levels were found in patients who were younger, had higher DBP levels, or were receiving medication on their first visits to a clinic, were receiving more intense treatment regimens at the beginning of the follow-up period, or had been under the care of the clinic for shorter periods. Patients who were more likely to remain in care were older, received more intense treatment regimens, had prior cardiovascular complications, or had been under the care of the clinic for a longer time. Higher annual costs were associated with higher entry DBP levels, shorter durations of care, more intense regimens, and prior cardiovascular complications. Overall, patient characteristics explained 13% of the variance in mean follow-up DBP, and 31% of variance in costs. Wide variations were found among clinics in clinical outcomes and costs. After controlling for differences in patient characteristics, clinic characteristics associated with better blood pressure control were more frequent clinic visits, shorter waiting times, more time spent in patient counseling, having therapists who had a single supervisor, and better staff satisfaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Cloning of the nucleocapsid protein gene of peste-des-petits-ruminants virus: relationship to other morbilliviruses.

Two independent cDNA clones, identified as representing the mRNA of the nucleocapsid protein gene of peste-des-petits-ruminants virus, were sequenced. The longest insert was 1662 nucleotides, not counting the poly(A) tail, and it was estimated that about 21 nucleotides were missing from the complete gene sequence. The sequence contained one long open reading frame encoding a protein of 525 amino acids with a predicted relative molecular mass of 58,008. Comparisons of the nucleic acid and protein sequences of all the morbillivirus nucleoproteins so far determined indicated two major subgroups in the morbillivirus genus of the Paramyxoviridae: one group included canine and phocine distemper viruses, and the other rinderpest, measles and peste-des-petits-ruminants viruses. Peste-des-petits-ruminants virus was found to be slightly more related to canine and phocine distemper viruses than were measles and rinderpest viruses.

Amino Acid Sequence↗
PubMed1994

Hemodynamic effects of bolus vs 2-h infusion of alteplase in acute massive pulmonary embolism. A randomized controlled multicenter trial.

Four centers participated in a double-blind study in which 53 patients with angiographically documented acute massive pulmonary embolism (baseline Miller index > or = 17/34 and mean pulmonary artery pressure > or = 20 mm Hg) were randomly assigned to treatment with either 0.6 mg/kg bolus injection of alteplase over 15 min with a maximum dose of 50 mg (bolus group; n = 36), or 100 mg of alteplase over 2 h (2-h group; n = 17). The primary objective was to compare the rapidity of resolution of pulmonary embolism as judged by the change in total pulmonary resistance (TPR) over the initial first hour. Further objectives were to evaluate the changes in TPR over the next 11 h and the degree of lung scan resolution at 20 to 28 h. At 1 h, TPR decreased by 29 +/- 17 percent in the bolus group and by 36 +/- 16 percent in the 2-h group (mean +/- SD; p = 0.19). Continuous monitoring of TPR revealed that this variable improved in both groups without significant intergroup differences over the 12-h study period, although TPR decreased initially faster in the 2-h group. At 20 to 28 h, the absolute improvements in the lung scan perfusion defect were 14 +/- 12 percent in the bolus group compared with 13 +/- 9 percent in the 2-h group, with no significant intergroup differences. Major bleeding occurred in one patient of the 2-h group (6 percent) and in three patients of the bolus group (8 percent) (p > 0.5). Four patients (three from the bolus group and one from the 2-h group) may have experienced recurrent pulmonary embolism during the hospital stay. Neither death nor intracranial bleeding occurred.

Acute Disease↗
PubMed1994

Characterization of a spontaneously transformed human endothelial cell line.

BACKGROUND: A line of cells was isolated from a focus observed in a human umbilical vein endothelial cell (HUVEC) culture, presumably the result of a spontaneous transformation event. EXPERIMENTAL DESIGN: The cell line was continuously cultured for 16 months, after which time, the proliferative rate, capacity to be cloned, and ability to be transfected was investigated. The cell line was analyzed for expression of endothelial cell markers, von Willebrand Factor, P selectin, and scavenger receptor. We also examined the tumor necrosis factor (TNF)-mediated upregulation of E-selectin, vascular cell adhesion molecule-1 and intercellular adhesion molecule-1. We evaluated the levels of expression and types of TNF-alpha receptor expressed by the cell line, and the cell lines response to interleukin-4 and interferon-gamma. CD34 expression of this cell line and the ability of transforming growth factor-beta to inhibit the TNF-alpha induction of E-selectin was examined. The ability to support neutrophil adhesion and transmigration, and generate capillary-like tubes in vitro was assessed. Finally, the karyotype and tumourigenicity of this line was established. RESULTS: This cell line (C11STH) has a doubling time comparable to that of normal HUVECs and has a trisomy of chromosome 8 and 11. The cell line is capable of generating colonies at clonal density, and is transfectable with efficiencies comparable to normal HUVECs. C11STH expresses von Willebrand factor, P-selectin, and scavenger receptor to an extent similar to passaged HUVECs and can be induced to express E-selectin, VCAM, and ICAM with TNF-alpha. C11STH expresses both the p55 and p75 subunits of TNF-alpha receptor at levels similar to HUVECs. The ability of interleukin-4 to enhance the expression of VCAM and reduce the TNF-alpha-mediated expression of E-selectin is maintained in this cell line. C11STH cells are unable to induce class II major histocompatibility antigen in response to interferon-gamma. However, interferon-gamma is able to synergize with TNF to enhance the expression of E-selectin. C11STH cells do not express CD34 or show transforming growth factor-beta inhibition of TNF-alpha induced E-selectin expression, functions indicative of primary, or early passage HUVECs. The cell line retains the ability to support neutrophil adhesion and transmigration and can generate patent tubes when seeded onto complex basement membrane gels. However, the cell line no longer has the ability to generate capillary-like vessels when seeded onto collagen gels in the presence of phorbol 12-myristate 13-acetate. CONCLUSIONS: C11STH has retained many of the normal characteristics of endothelial cells, is able to proliferate at clonal density, and is easily transfectable. The line will provide a useful resource for endothelial cell biology. Its ability to make capillary-like tubes on basement membrane gels, but not on collagen will provide a powerful tool with which to further analyze the processes involved in angiogenesis, and will enable us to define the role of specific proteins in angiogenesis. Since C11STH shows tube competence on Matrigel, but is not tube competent on collagen, our studies suggest that capillary-tube formation on Matrigel and collagen occur via qualitatively different mechanisms. Thus, this cell line provides the opportunity to examine the signalling mechanisms required to generate capillary tube formation. These may include the involvement of matrix molecules, the production of proteases and inhibitors, gene regulation and kinases or phosphatases.

Cell Adhesion↗
PubMed1994

Laminar distribution and morphology of NADPH-diaphorase containing neurons in the optic tectum of the pigeon.

The laminar distribution and morphology of nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) containing neurons is studied in the optic tectum (OT) of the pigeon. NADPH-d positive cells are arranged in three bands: the first band, in the stratum griseum et fibrosum superficiale, sublayer II a, is formed by small marginal and horizontal neurons; the second band is broad and extends throughout layers II i-j and III (stratum griseum centrale); the third band lies around the tectal ventricle, and consists of neurons in the stratum griseum profundum (SGP) and tanycytes. A comparison with Golgi-impregnated sections suggests that most NADPH-d positive cells in the OT have local or intratectal axons, while the large efferent neurons in layers IIj and III are NADPH-d negative. Similarities and differences between NADPH-d containing neurons in the avian OT and the mammalian superior colliculus are discussed. The processes of NADPH-d positive neurons in the SGP and of the tanycytes of the tectal ventricle form dense fascicles traversing the stratum album centrale. They surround and contact the radial blood vessels that originate in the SGP. We discuss the possibility that NADPH-d, or nitric oxide synthase, plays a role in the regulation of local blood flow in the deep tectal layers.

Amino Acid Oxidoreductases↗
PubMed1994

[Conventional or laparoscopic cholecystectomy in treatment of acute cholecystitis?].

Elective laparoscopic cholecystectomy has become established as the procedure of choice for the treatment of symptomatic cholecystolithiasis while the application of this method for acute cholecystitis has been propagated with restrainment. In a prospective study 114 conventional (right subcostal incision) and 102 laparoscopic cholecystectomies for this indication were compared. The overall complication rate amounted 10.7% for conventional cholecystectomy and 8.9% for laparoscopic cholecystectomy. The rate of conversion was 9.2%. Due to the fact that intraoperative cholangiography was carried out in 60% of conventional cholecystectomies and in only one of laparoscopic procedures the arithmetic advantage of minimally invasive technique with respect to blood loss and operating time does not allow final conclusions. These patients however recovered clearly faster and could be discharged after an average of 5.2 +/- 4.2 postoperative days, while the hospitalisation after conventional operations amounted to 7.6 +/- 3.8 days (p < 0.001).

Acute Disease↗
PubMed1994

[Laparoscopic single staple suture--initial clinical experiences].

Based on the results of our own animal experimental investigations, the first clinical employment of single titanium staples in the creation of suture lines on the gastrointestinal tract was carried out. These staple lines are most favorably adapted for laparoscopic use. First experiences with 10 staple lines, 6 of which were anastomoses, are reported. Neither insufficiencies nor stenoses were detected. Until now there are no long-term observations. The technique seems to allow open or laparoscopically the creation of standardized suture lines in any segment of the gastrointestinal tract.

Anastomosis, Surgical↗
PubMed1993

Developmental changes in layer I of the human neocortex during prenatal life: a DiI-tracing and AChE and NADPH-d histochemistry study.

The development of fetal layer I (marginal zone, MZ) was studied in the human neocortex by using DiI tracing and AChE and NADPH-d histochemistry, and examining the Nissl-stained material of the Yakovlev Collection. We describe the sequential maturation of the Cajal-Retzius (CR) cells and the granule cells of the subpial granular layer (SGL), and the close relationship between both. The first CR cells appear in the primordial plexiform layer, at 6 gestational weeks (GW). After the formation of the cortical plate, they settle under the pial surface. At 13 GW, the SGL begins to form around the CR cells. The horizontal members of a polymorphic population of CR cells begin to mature at 13 GW, and the intermediate and vertical forms differentiate at 16 and 18 GW, respectively. All CR cells project into an axonal plexus in the lower third of the MZ. From 18 GW, CR cells and SGL become segregated, and the polymorphic CR cells lie now below the SGL, with which they remain connected by ascending processes. Granule cells invade the lower MZ contacting somata and processes of CR cells. The somata of vertical CR cells elongate until 23/24 GW when they show degenerative signs. After 24 GW, all polymorphic CR cells die. Granule cells degenerate after 24 GW; the SGL disappears at 28/30 GW. A population of persisting CR cells, morphologically different from the transient polymorphic forms, appears in a subpial position and survives in small numbers throughout life. Small non-CR neurons differentiate first in the lower half of layer I, thereafter also in the upper half. Histochemically, all CR cells are AChE-positive; they contain NADPH-d only transiently at 20 GW. We propose that CR cells and SGL provide a transient innervation network for the developing cortical plate at a time when the definitive fiber systems of the molecular layer are not yet established.

Acetylcholinesterase↗
PubMed1993

Postnatal development of NADPH-diaphorase activity in the superior colliculus and the ventral lateral geniculate nucleus of the rat.

We have studied the postnatal development of dihydronicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) activity in the superior colliculus (SC) and the ventral lateral geniculate nucleus (LGv) of the rat. We describe two different developmental patterns of NADPH-diaphorase activity. The first pattern, observed in the deep layers of the SC, shows a transient activity during the first week which progressively decreases during the following two weeks. The second pattern is observed in the superficial layers of the SC and in the LGv. They become positive during the first week, their NADPH-d activity increases progressively during the second and third weeks, reaching the adult pattern at the fourth week. On the whole, the developmental chronology of the laminar distribution of NADPH-d in the SC displays an inside-out pattern. Our results suggest that NADPH-d activity may play different roles at different stages of the developing nervous system.

Animals↗
PubMed1993

A highly conserved repetitive sequence from Physarum polycephalum contains nucleotide arrangements similar to replicator sequences.

An interspersed repetitive sequence from Physarum polycephalum has been cloned and analysed. The 394 bp sequence is highly conserved and contains several homopolymeric (dA)-(dT) tracts capable of forming bent DNA structures and a 10/11 match to the yeast-ARS-consensus sequence. The repetition frequency of the described sequence is about 3000 to 7000, a number that would fit with the distribution of replicator segments in Physarum.

Animals↗