Search PubMed⌕ Search

Biomedical subjects

T Schmid

Publications and source records attributed to T Schmid.

At least 55 records · Page 3Linked to original sources
PubMed1997

Parathyroidectomy after renal transplantation: a retrospective analysis of long-term outcome.

BACKGROUND: Advanced hyperparathyroidism refractory to active vitamin D continues to be a problem and frequently forces the nephrologist to resort to parathyroidectomy. One particular aspect is persisting advanced hyperparathyroidism after renal transplantation. Published information on this point is fragmentary. DESIGN: Retrospective analysis. PATIENTS: Between 1983 and 1995 a total of 456 patients with renal secondary hyperparathyroidism were subjected to parathyroidectomy (PTX) of whom 103 were transplanted or had at least a history of renal transplantation. The present analysis concerns 37 patients who had a functional renal graft at the time of PTX and were followed for up to 13 years. PTX was performed after an average of 36.7 months after renal transplantation. OUTCOME: Thirteen patients experienced rejection and became dialysis-dependent. Twenty-four patients had stable function of the renal graft. Seven patients died during follow-up. Hypoparathyroidism post-PTX developed in 4/37 patients, but could be overcome by replantation of cryoconserved parathyroid tissue. FREQUENCY ESTIMATE: A total of 2632 renal transplants were performed in the catchment area. As a minimum estimate 3.91% of patients with a functional graft required PTX. RECOMMENDATION: Parathyroidectomy should be considered early in cases with advanced secondary renal hyperparathyroidism, since renal transplantation does not necessarily guarantee reversibility of parathyroid overactivity.

Adult↗
PubMed1997

Treatment of hepatic cysts in the era of laparoscopic surgery.

BACKGROUND: Liver cysts are not uncommon. Rarely, they become symptomatic and require intervention. Surgery is the usual form of treatment; laparoscopic cyst unroofing has recently been introduced. METHODS: The current status of diagnosis and conventional therapy of hepatic cysts was summarized. The surgical literature was surveyed to collect all reported cases of minimally invasive treatment of these lesions, and the advantages and limitations of the methods were evaluated. RESULTS AND CONCLUSION: The general application of the minimally invasive technique should await a thorough evaluation of the operative complications and the outcome in terms of cyst recurrence in larger series of patients. However, laparoscopic wide cyst unroofing and laparoscopic cyst excision will probably become the methods of choice for the treatment of symptomatic liver cysts in carefully selected patients.

Cysts↗
PubMed1996

Numerical and experimental dosimetry of Petri dish exposure setups.

Crawford TEM cells are often used to expose cell cultures or small animals in order to study the effects caused by high-frequency fields. They are self-contained, easy-to-use setups that provide a rather homogeneous field distribution in a large area around its center, corresponding approximately to far-field conditions. However, a number of conditions must be met if such TEM cells are intended to be used for in vitro experiments. For instance, poor interaction with the incident field must be maintained to avoid significant field disturbances in the TEM cell. This is best achieved with E-polarization, i.e., when the E-field vector is normal to the investigated cell layer lining the bottom of a synthetic Petri dish. In addition, E-polarization provides the most homogeneous field distribution of all polarizations within the entire layer of cells. In this paper, we present a detailed dosimetric assessment for 60 and 100 mm Petri dishes as well as for a 48-well titer plate at 835 MHz. The dosimetry was performed by using numerical computations. The modeling and the simplifications are validated by a second numerical technique and by experimental measurements. For thin liquid layers, an approximation formula is provided with which the induced field strength for many other experiments conducted in Petri dishes can be assessed reliably.

Absorption↗
PubMed1996

Simultaneous transplantation of isolated hepatocytes reduces rejection of small bowel allografts and improves survival in the rat.

Hepatocytes transplanted some days prior to vascularized allografts were shown to have the potential to prolong allograft survival in the rat. In the present study, hepatocytes and small bowel allografts were transplanted simultaneously in a Lewis (donor)-Brown Norway (recipient) rat model. 8-15 x 10(6) liver cells were injected into the spleen of small bowel recipients. The administration of at least 10 mg cyclosporine A (CyA)/kg over 3 days was necessary to prevent early rejection of hepatocytes. In groups simultaneously receiving hepatocytes, small bowel grafts and 10 mg CyA/kg over 3 days, a significant mitigation of rejection and a prolongation of survival was achieved, compared to groups receiving solely small bowel grafts and 10 mg CyA/kg over 3 days. We conclude that simultaneously transplanted hepatocytes exert a protective effect on a grafted organ from the same donor, provided that early rejection of hepatocytes is prevented by sufficient immunosuppression.

Animals↗
PubMed1996

Integrin molecules: a clue to the non-metastasizing behaviour of basal cell carcinomas?

Does the integrin profile of basal cell carcinomas explain their non-metastasizing behaviour? Immunohistochemical Investigation of nodular (n = 31) and superficial (n = 17) tumours yielded a strong expression of alpha 2, alpha 3, alpha 6, beta 1, and beta 3 subunits and a weak expression of alpha 4 subunits by the epithelial tumour component. alpha 5 subunits were focally detected in superficial basal cell carcinomas but not in the nodular type. Tumour cells were nearly devoid of alpha v subunits. The integrin profile of basal cell carcinomas does not differ essentially from that of metastasizing tumour varieties and cannot be regarded as a major reason for the non-metastasizing phenotype of basal cell carcinomas.

Antibodies, Monoclonal↗
PubMed1996

Expression of CD44 isoforms in basal cell carcinomas.

The expression of CD44 isoforms (CD44std, CD44v6, CD44v10) was investigated by an immunohistochemical technique in 42 basal cell carcinomas (BCC) of the superficial and nodular variety. All BCCs studied displayed very low amounts of CD44std, a receptor for hyaluronic acid. Except for single CD44std-positive cells located preferentially in the central parts of the BCC nests, the bulk of the tumour formations were CD44std-negative. CD44v6 showed a heterogeneous distribution pattern accentuated in the peripheral palisading tumour cells. In superficial BCCs, the labelling intensity for CD44v6 increased with the size of the tumour nests. CD44v10 was not detectable in BCCs. Our findings support the notion that CD44v6 is not linked to the metastatic proclivity of tumours originating from keratinocytes. We suggest that the very low expression of the receptor for hyaluronic acid (CD44std) may be one of the factors which block the formation of metastases from BCCs.

Antigens, Neoplasm↗
PubMed1995

Environmental and policy approaches to cardiovascular disease prevention through nutrition: opportunities for state and local action.

This article reviews environmental and policy intervention approaches to cardiovascular disease prevention through nutrition and recommends opportunities for state and local health departments to initiate and participate in environmental and nutrition policy initiatives. By addressing these complementary aims, the authors hope to stimulate further efforts to achieve progress in nutrition promotion among state and local health-related organizations. Key categories of opportunity to develop new or expanded nutrition policies and environmental strategies include economic incentives, food assistance and feeding programs, regulations for institutional food service operations, and nutrition services in health care. Environmental strategies to reduce barriers to following dietary guidelines, such as point-of-choice programs and school nutrition programs, should be tailored for local communities and widely disseminated. In addition, current federal policy efforts, notably nutrition labeling rules, will provide a valuable focal point for state and local advocacy, education, and monitoring.

Cardiovascular Diseases↗
PubMed1994

Myoelectric activity during small bowel allograft rejection.

The effect of rejection on myoelectric activity of an orthotopically transplanted small intestinal segment (group I, N = 14) was studied. Electrodes were placed on grafts and recipient small bowel. Isografts (group II, N = 5) and native bowel (group III, N = 5) served as controls. The first morphological signs of rejection were seen on day 6 and steadily progressed until day 11, when the cellular infiltrate involved all layers of the bowel wall. Slow-wave frequencies remained unchanged throughout the observation period. No difference was detectable between grafts (group I: 31.9 +/- 1.65; group II: 31.36 +/- 0.7) and native bowel after transection (group I: 32.16 +/- 1.78; group II: 31.50 +/- 1.01), which was different (P = 0.0001) from intact bowel of group III animals (38.4 +/- 0.81). Irregular MMCs were detectable in grafts from day 5 on and replaced after food intake by random spiking activities. At day 8, spiking activities disappeared in allografts, which showed a still preserved mucosal architecture, while slow-wave activities continued. These findings demonstrate that intestinal allografts during rejection develop paralysis before mucosal destruction is established, which might be of clinical relevance.

Action Potentials↗
PubMed1994

Protective effects of various preservation solutions on cultured endothelial cells.

Vascular endothelium represents the first target in organ preservation and plays an important role in reperfusion injury. Bovine aortic endothelial cells were cultivated and the most commonly used preservation solutions, such as University of Wisconsin HTK (Brettschneider's histidine-tryptophane-ketoglutarate), and Euro-Collins solutions were tested on the endothelial monolayer. In addition, one group of cultivated cells was preserved with cold saline solution, and endothelial monolayers grown in culture medium were used as controls. The quality of preservation was assessed after 24, 48, and 72 hours of cold storage. Reperfusion was simulated and its effects were observed by reincubation in culture medium at 37 degrees C for 6 hours. The total number of cells, cell viability (determined using trypan blue exclusion), and morphologic alterations were determined. Prostacyclin release was evaluated as a biochemical marker. University of Wisconsin solution maintains more than 99% cell viability after rewarming after both 24 and 48 hours of cold storage. After 72 hours, 86.7% of cells were still viable. Preservation with HTK and Euro-Collins solution allowed cell survival for only 24 hours (96.7%, HTK; 49.9%, Euro-Collins), with no viable cells seen after 48 hours. The cold saline-preserved sample showed 57.8% viable cells after 24 hours and 29.7% after 48 hours. No viable cells were detectable after 72 hours. Light microscopy revealed several patterns of both structural damage and intracellular change (nucleus and cytoplasm) in the endothelial monolayer after preservation with HTK, Euro-Collins solution, and cold saline solution. No morphologic alterations were seen in the University of Wisconsin solution group for as long as 72 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[Experiences with the Kock continent ileostomy].

First experiences with Kock-pouches (KP) in 34 patients operated on between 1987 and 1992 with stapler-stabilization of the nipple-valve are reported. 18 patients (52.9%) suffered from ulcerative colitis (CU), 7 patients (20.6%) from familiar adenomatous polyposis (FAP) and 9 patients (26.5%) from Crohn's colitis (CC). Each patient was inappropriate for ileo-anal pouch-procedure (IAP) and desired fecal control. Special indications for KP were identic with medical contraindications for IAP in 52.9%, refusal of IAP in 17.6% and loss of sphincter in 29.4%. In 25 patients with CU and FAP the rate of specific early complications was 24%. In 5 of 6 cases operative correction was successful. The rate of success was 96%, which could be maintained over time with a rate of 8.3% of late complications, that had to be corrected. In 9 patients with CC the rate of success was 77.8% due to two pouch resections in the early postoperative course. It decreased to 66.6% in the further course due to another resection later on. In CC, 3 out of 7 patients had repeated reoperations due to inflammatory complications of the disease not impairing pouch-function. A severe pouchitis was only observed in 2/18 patients with CU (11.1%). Thus, high rates of success in KP-surgery can be achieved for CU and FAP-patients. But it has to be kept in mind, that KP is not in concurrence with IAP, it is also an alternative to Brooke-ileostomy. Patients with CC are less appropriate, because the necessity for repeated reoperations due to recurrent disease reduces significantly the overall benefit of the patients, even if continence is preserved.

Adenomatous Polyposis Coli↗
PubMed1994

[Preventive total thyroidectomy in children with MEN IIa syndrome].

Three children of MEN IIa-families underwent a prophylactic total thyroidectomy (at the age of 4, 7 and 8 years). Pathologic examination showed a bilateral C-cell-hyperplasia in each case. The annual follow-up of the physically and mentally well-developing children so far showed normal calcitonin provocative testing. Members of risk families should undergo a screening program as early as possible.

Carcinoma, Medullary↗
PubMed1993

The pattern of rejection after combined stomach, small bowel, and pancreas transplantation in the rat.

This study was designed to investigate whether in combined stomach, small bowel, and pancreas transplantation allograft rejection occurs in the individual organs concomitantly and with the same intensity. Heterotopic en-bloc transplantation of the stomach, small bowel, and pancreas was performed in a Lewis-to-Brown Norway rat combination. Group 1 animals received no immunosuppressive therapy while animals in group 2 were treated with cyclosporin (10 mg/kg body weight, orally) daily. Grafts were histologically evaluated on the 5th (subgroups 1a and 2a) and 10th (subgroups 1b and 2b) postoperative days. The degree of rejection was defined as moderate, intermediate, or severe according to predefined criteria. The results indicate that the small bowel is more susceptible to rejection than either the stomach or the pancreas. Mucosal biopsies of the stomach are unlikely to provide a reliable guide to rejection in the small bowel.

Animals↗