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Biomedical subjects

M Wagner

Publications and source records attributed to M Wagner.

At least 451 records · Page 25Linked to original sources
PubMed1995

[Comparison of the effectiveness of sodium azide and merthiolate as bacteriocidal agents--a NMR study].

The pseudohalogenide sodium azide (NaN3) and the organometallic mercury compound merthiolate (sodium salt of ethyl mercurithiosalicylate) are commonly used as preserving solutions for biomaterials. In the present paper, these preserving solutions were compared for their efficacy in preserving porcine articular cartilage. For this purpose, porcine articular cartilage was incubated with phosphate buffer containing the corresponding amounts of NaN3 or merthiolate. Supernatants were assayed using NMR spectroscopy, and the content of soluble saccharides was determined using the dye Alcian blue. The results obtained clearly indicate that merthiolate is more effective than sodium azide. This makes the former a more suitable preserving agent for the storage of cartilage. A significant decrease in the lactate concentration, and enhancement of the acetate and the N-acetyl resonances indicate degenerative changes in the cartilage. However, when a large excess of sodium azide is used, its efficacy approaches that of merthiolate.

Animals↗
PubMed1995

Effects of pharmacological modulation of intracellular signalling systems on retinal pigment epithelial cell attachment to extracellular matrix proteins.

Complication of retinal detachment by proliferative vitreoretinopathy (PVR) is common. In the contraction of intraocular collagen matrices which occurs in PVR cell proliferation, migration and adhesion seem to be more important than any inherent cellular contractility. The aim of this study was to investigate the pharmacological inhibition of adhesion of retinal pigment epithelial cells to extracellular matrices. The adherence of human RPE lines to a range of ten substrates was assessed to determine their preferred substrates for attachment. The effect of pharmacological inhibitors and stimulators of protein kinase C, cyclic AMP and calcium/calmodulin intracellular signal transduction systems on attachment to substrates was investigated. RPE cells showed a clear substrate preference for fibronectin, and slight preference for collagen type I. Modulation of the protein kinase C and cAMP pathways had relatively minor effects upon RPE attachment. Increasing intracellular calcium concentration reduced RPE attachment to 12% of control, whilst reducing intracellular calcium had a less marked, although significant effect. Down-regulation of calmodulin reduced attachment to 17% of control. The drug tamoxifen, and the experimental calmodulin antagonist J8, produced significant inhibition of attachment even when cells had been allowed to adhere for 24 h prior to exposure to these agents. The adhesion of RPE to extracellular matrices may be markedly affected by drugs which modulate the intracellular calcium and calmodulin signalling systems. Calmodulin antagonists warrant further investigation as possible pharmacological inhibitors of PVR.

Animals↗
PubMed1995

[Infected hip joint prosthesis. Viewpoints for 1-stage and 2-stage prosthesis exchange].

When treating an infected hip prosthesis, there are a number of medical, technical and biomechanical considerations. No ideal solution for all problems is available. In individual cases an optimal compromise must be found. The means for curing the infection and the one for maintaining hip stability can counteract each other. Basically, three options are available: removal of the prosthesis without replacement and one- or two-stage replacement. With all three options thorough surgical debridement is vitally important. The introduction of antibiotic cement and cementless titanium implants, together with very effective local antiseptics, has remarkably improved our treatment of this problem. Therefore, removal of infected prostheses without replacement is not as well accepted now as it has been in the past.

Anti-Bacterial Agents↗
PubMed1995

[Local antisepsis in infected total hip endoprosthesis].

Between 1991 and 1993, 34 infected total hip prostheses were treated with the topical antiseptic hexamethylenbiguanide (Lavasept) in addition to thorough débridement of infected and necrotic tissue and systemic antibiotic administration. In 4 cases (group 1) a contaminated hematoma was treated within the first 3 weeks after joint replacement. Soft tissue revision without removal of the prosthesis was performed in 6 cases (group 2). In 18 cases (group 3) a one-stage exchange of the infected prosthesis was done. In 6 cases (group 4), local and general conditions were so poor that the prosthesis was removed without replacement. The success rate was 100% in group 1, 20% in group 2, and 77% in group 3. In group 4, 1 patient died of respiratory problems 12 days after surgery while in 2 patients the infection healed uneventfully and in 1 patient healing was achieved after a second revision. An 81-year-old patient in poor general condition had an impressive improvement of his severe infection, although very minor drainage continued. Hexamethylenbiguanide has proven to be a useful supplement to thorough surgical revision. However, longer follow-up data are required.

Adult↗
PubMed1995

Hereditary multiple exostosis and chondrosarcoma: linkage to chromosome II and loss of heterozygosity for EXT-linked markers on chromosomes II and 8.

Hereditary multiple exostosis (EXT) is an autosomal dominant disorder characterized by bony exostoses at the ends of the long bones. Linkage studies have recently suggested that there are three chromosomal locations for EXT genes, 8q24.1 (EXT1), the pericentric region of 11 (EXT2), and 19p (EXT3). As part of a larger study to determine the frequencies of the three EXT types in the United States, we have ascertained a large multigenerational family with EXT and one family member with a chondrosarcoma. This family demonstrated linkage of the disease to chromosome 11 markers. The constitutional and tumor DNAs from the affected family member were compared using short-tandem-repeat markers from chromosomes 8, 11, and 19. Loss of heterozygosity (LOH) in the tumor was observed for chromosome 8 and 11 markers, but chromosome 19 markers were intact. An apparent deletion of the marker D11S903 was observed in constitutional DNA from all affected individuals and in the tumor sample. These results indicate that the EXT2 gene maps to the region containing marker D11S903, which is flanked by markers D11S1355 and D11S1361. Additional constitutional and chondrosarcoma DNA pairs from six unrelated individuals, two of whom had EXT, were similarly analyzed. One tumor from an individual with EXT demonstrated LOH for chromosome 8 markers, and a person with a sporadic chondrosarcoma was found to have tumor-specific LOH and a homozygous deletion of chromosome 11 markers. These findings suggest that EXT genes may be tumor-suppressor genes and that the initiation of tumor development may follow a multistep model.

Chondrosarcoma↗
PubMed1995

[Ultrastructural immunocytochemical study of lymphocyte subsets from patients with systemic lupus erythematosus and bearing tubuloreticular inclusions].

The tubuloreticular inclusions (TRI) correspond to a modification of the endoplasmic reticulum, observed in different pathological conditions, the most frequent being immune disorders. In the systemic lupus erythematosus, they are present in 2.7% to 4.4% of circulating lymphocytes in 4 patients out of 5. Using an immunogold technique, the TRI were identified only in the T lymphocytes (26/331 T lymphocytes versus 0/79 B lymphocytes, p < 0.01 Chi square) and more precisely in the T4 "Helpers" (16/218 T4 versus 0/123 T8, p < 0.01 Chi square).

Adolescent↗
PubMed1995

[Atrophic thyroiditis: an unusual course of a Basedow-like variation of Hashimoto disease. Apropos of a case].

This case concerns a 27-year-old man with a very high level of anti-thyroid antibody and pretibial elephantiasis myxedema which developed progressively over several years following subtotal thyroidectomy for << hashitoxicosis >>. Complementary resection of the thyroid stump was performed ; under microscopic examination this stump presented an aspect of atrophic thyroiditis. This unusual development towards atrophic thyroiditis raises the problem of the relations between the various forms autoimmune thyroiditis.

Adult↗
PubMed1994

Can we talk? Inpatient discussions about advance directives in a community hospital. Attending physicians' attitudes, their inpatients' wishes, and reported experience.

BACKGROUND: The attitudes of hospitalized patients and their attending physicians about advance directives have not been well studied. We compared these attitudes and explored relationships between them and the frequency of actual directives and directive discussions during hospitalization. METHODS: We conducted scripted interviews with 258 (94.5%) of 273 patients admitted consecutively to the acute medical service of a community teaching hospital in Rochester, NY, and contemporaneously surveyed their attending physicians (n = 68) regarding attitudes about advance directives. Primary outcome measures were patients' willingness to discuss directives, actual physician-patient directive discussions, and patients' preferences for life-sustaining treatments. Also measured were physicians' indications for directive discussions, their reasons not to discuss directives, and their knowledge and attitudes about life-sustaining treatments. RESULTS: Eighty-one percent (172/212) of competent interviewed patients either did (100) or wanted to (72) discuss advance directives in hospital. Forty-one percent of patients chose to forgo cardiopulmonary resuscitation; 24% to 41% refused other life-sustaining interventions (intensive care unit admission, mechanical ventilation, cardioversion, vasopressors). Overall, 90% (246/273) of all patients met at least one of three criteria reported by their physicians as indications for advance directive discussions: age at least 75 years, critical or potentially fatal illness, and patients' desire to discuss directives. Multiple logistic regression revealed that these same variables predicted patients' willingness to discuss cardiopulmonary resuscitation, their preferences to receive or forgo cardiopulmonary resuscitation, and the frequency of physician-patient discussions about these issues. CONCLUSIONS: Most medical inpatients in a community hospital want to, are able to, and meet their own physicians' indications to discuss advance directives. Hospitalization presents an unrealized opportunity for physicians and patients to initiate these discussions.

Adolescent↗
PubMed1994

[Laparoscopic suturing of a perforated gastroduodenal ulcer].

The mortality rate for perforated peptic ulcer ranges from 10 to 30%. Age above 70 years, preoperative shock, operation more than 24 hours from the time of acute onset, and poorly controlled concurrent illness are considered to be risk factors. Individuals with any of these features are deemed unfit for definitive surgery and should undergo simple omental patch suture alone. This case report details the laparoscopic management of an 86-year-old female with a ruptured duodenal peptic ulcer who was receiving corticosteroids and a non-steroidal antiinflammatory drug. Laparoscopy is of diagnostic value and permits efficient cleaning of the abdominal cavity. Provided the laparoscopic principles of management are essentially the same as those adhered to during open surgery, the minimally invasive procedure may help to reduce postoperative morbidity and mortality.

Aged↗
PubMed1994

A panel of radiation hybrids for human chromosome 8.

We have developed a panel of radiation hybrids containing fragments of chromosome 8 as the only human material. The human chromosome content of each cell line was determined relative to an ordered map of sequence tagged sites (STSs) specific to chromosome 8. Between one and four fragments of chromosome 8 were identified in each cell line, with an average of 25% of the STSs retained in each line. Subclones of one radiation hybrid were examined to determine whether all cells within a line are homogeneous with respect to chromosome 8 sequence content. There was considerable variability between subclones, with retention rates for individual STSs ranging from 5 to 100% in different clones. Furthermore, a gradient of retention of sequences along the length of one large chromosome fragment was found, suggesting that sequence loss involved deletions from one end of the fragment at early stages in the establishment of the cell line. We have also made use of the radiation hybrids to develop novel sequence tagged sites for the pericentromeric region of chromosome 8.

Adenine Phosphoribosyltransferase↗
PubMed1994

Fucose and fucose-containing sugar epitopes enhance hippocampal long-term potentiation in the freely moving rat.

Male Wistar rats were intrahippocampally injected with L-fucose and the sugar epitope 2'-fucosyl-lactose prior to induction of long-term potentiation (LTP). Both substances had only a minimal and short-lasting depressive effect on the monosynaptically evoked field potential recorded in the dorsal blade of the dentate gyrus of freely moving rats upon stimulation of the perforant pathway. However, LTP induced by fractionated tetanization of the perforant pathway, which declined within 24 h in control animals injected with Lactose, remained at the initial level even 48 h after tetanization (difference to the control group significant with P < 0.01). The results support earlier findings which have indicated a participation of fucosylated macromolecules in the maintenance of LTP. Different molecular mechanisms concerning the effect of both substances and the significance of the data in elucidation of the relationship between LTP and memory formation are discussed.

Animals↗
PubMed1994

[Laparoscopic intestinal surgery].

The objective of the present study was to demonstrate the feasibility of laparoscopic bowel surgery. From June 1990 to September 1993 14 small bowel and 15 colon operations were performed laparoscopically in the surgical department of Aarberg Hospital. The results have been analyzed retrospectively. The indication for all small bowel operations was intestinal obstruction. Adhesiolysis, hernia repair and resections were performed either by laparoscopy or by laparoscopically assisted surgery. There were no complications. Laparoscopy therefore has proven to be a good method for treating intestinal obstruction of various origin. 11 colon resections were performed without anastomotic leakage. There were two conversions to laparotomy. Three complications occurred but resolved spontaneously. Two patients died from causes unrelated to the laparoscopic procedure. Our results demonstrate that laparoscopic resections of the colon are feasible. Further evaluation is needed to assess their clinical value.

Adolescent↗