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Biomedical subjects

H D Becker

Publications and source records attributed to H D Becker.

At least 163 records · Page 9Linked to original sources
PubMed1994

TEM results of the Tuebingen group.

From August 1st 1989 to May 1st 1993, 190 rectal adenomas and 75 carcinomas were locally excised with the TEM technique. The mortality was 0.4%, the rate of complications which required surgical re-intervention was 3% in adenomas and 8% in carcinomas. The final histology of the removed carcinomas revealed 44 pT1, 23 pT2 and eight pT3 stages. In two of the eight re-resected patients with pT1 low-risk tumours, residual primary tumour but no lymph node metastases were found. In contrast to this, three of the eleven re-resected patients with pT2 low-risk tumours had already developed lymph node metastases. After an average follow-up time of 14 months, two recurrences were observed in the group of the only locally treated patients with pT1 low-risk carcinomas. Both underwent a secondary procedure for cure but in late tumour stages. No recurrence was diagnosed so far among the re-resected patients.

Adult↗
PubMed1994

[Lichtenstein alloplastic repair of inguinal hernia].

Tension-free repair, a prerequisite for long-term stability, cannot always be achieved with conventional techniques established for groin reconstruction. Lichtenstein gathered substantial experience simply by closing the hernia in a tension-free fashion using prosthetic material. However, most surgeons fearing graft infection are reluctant to further evaluate this technique. In a feasibility study we entered 70 patients (29 patients with recurrent hernia) receiving a polypropylene mesh (Marlex) to bridge the defect from the inguinal ligament to the internal oblique muscle. Only 1 wound infection and 1 local hematoma requiring reoperation were observed. Nearly 2 years follow-up data revealed no case of recurrence. The Lichtenstein procedure deserves more attention from surgical community and might be a reliable technique esp. in large hernias and redos.

Adult↗
PubMed1994

Highly polarized primary urothelial cells from human ureter grown as spheroid-like vesicles.

Epithelial cells growing in vitro are frequently non-polarized and lack histophysiological characteristics. Furthermore, the quality of two-dimensional cell layers is limited by the physico-chemical properties of the support. Therefore, for an in vitro system to reflect the normal epithelial physiology, it is necessary to maintain the inner and outer geometrical configuration of the cells. In order to avoid the disadvantages of two-dimensional cultures we have established an in vitro model that closely resembles the in vivo situation. Human ureteral epithelial cells (HUEC) were used to prepare multicellular vesicles which maintain a geometrically intact cell organization that is not achieved in conventional cultures. Light and electron microscopy investigations showed the morphology of the cells to be similar to that in situ. HUEC vesicles are more in vivo-like than two-dimensional cultures and therefore represent a suitable model for a variety of research purposes including studies on the pathogenesis of micro-organisms.

Cell Aggregation↗
PubMed1994

[Stimulation of wound healing with thrombocyte growth factors in treatment of chronic unhealed wounds].

The management of chronic wounds remains a challenge for various medical and surgical specialties. General strategies include local wound care, surgery, skin grafting, debridement, and vascular reconstruction. However, many wounds remain resistant to conventional therapies. Because platelet factors are important in the normal mechanism of wound healing, we report on the topical application of platelet-derived growth factor. Our initial results suggest that the topical application may stimulate and promote healing of chronic wounds.

Administration, Topical↗
PubMed1994

Technique of endoscopic mediastinal dissection of the oesophagus.

Conventional transhiatal dissection of the oesophagus is usually performed without visual control. The attendant danger of this is that complications such as bleeding and tracheal lesions may be overlooked. This problem can be avoided by the use of an endoscopic operation system. This report describes a new technique of endoscopic microsurgical dissection of the oesophagus (EMDOE) and the results of the first 35 cases. Under visual control with a specially designed mediastinoscope the soft tissue surrounding the oesophagus is carefully dissected, and the oesophageal blood vessels can be safely exposed, coagulated and divided. The dissection begins cervically and proceeds along the oesophagus down to the oesophagocardiac junction. A simultaneously working abdominal team helps remove the oesophagus, which is then replaced by a stomach tube. Although the method is still under evaluation, results to date have been especially good for small distal tumors, especially adenocarcinomas.

Adenocarcinoma↗
PubMed1993

High-performance liquid chromatographic separation of biogenic polyamines using 2-(1-pyrenyl)ethyl chloroformate as a new fluorogenic derivatizing reagent.

The application of a new fluorogenic pre-column derivatizing reagent, 2-(1-pyrenyl)ethyl chloroformate (PEOC), is reported for the separation and detection of biogenic polyamines using column liquid chromatography. The development of the method included the optimization of excitation and emission wavelengths, efficient gradient programming, derivatization temperature, time, and pH. Minimum detection limits, linear ranges, reproducibility, and recovery from analyzed samples were determined. The procedure was applied to hydrolyzed serum samples taken from healthy individuals and cancer patients. Separation of PEOC-derivatized polyamines from the serum hydrolysis by-products was successful and detection limits were more favorable than those previously reported for 9-fluorenyl-methyl chloroformate-derivatized polyamines.

Biogenic Amines↗
PubMed1993

Morphological studies of graft pancreatitis following pancreas transplantation.

Morphological findings in the initial stages of graft pancreatitis were studied systematically in sequential biopsies of 16 human pancreatic allografts. In 14 patients clinical and morphological signs of graft pancreatitis developed in the early postoperative period. In all cases disturbances in the integrity of structures within acinar cells occurred during ischaemia. In ten cases activation of autophagocytosis occurred following reperfusion, with acceleration of cellular metabolism. After reperfusion a marked leucocyte reaction occurred with a later single acinar cell necrosis in six cases. At the same time, high serum pancreatic enzyme concentrations were observed in all patients following transplantation. Exocrine secretion from the allografts via the pancreatic duct was reduced, correlating with the severity of graft pancreatitis. Studies in this clinical situation might complement analyses of the cascade of morphological and pathophysiological reactions during the early stages of other types of acute pancreatitis.

Humans↗
PubMed1993

New technique for sigmoid colectomy.

A combination of laparoscopic and rectoscopic procedures has enabled complete resection of the sigmoid colon and eliminated the need for minilaparotomy when constructing the anastomosis or withdrawing the specimen. This combined procedure was performed in different ways in a series of animal models until the definitive technique had been standardized. These techniques were then successfully used in 15 consecutive medium-sized pigs. Histological evaluation of the specimens, including the anastomosis (examined 2-3 weeks after operation) confirmed the efficacy and safety of the method.

Anastomosis, Surgical↗
PubMed1993

Intestinal stenosis and perforating complications in Crohn's disease.

The charts of 384 patients with Crohn's disease were reviewed to assess the prognostic value of a bowel stenosis documented at the time of initial diagnosis for the occurrence of perforating (abscess, fistula, free perforation) or obstructing complications requiring surgical intervention. Mean follow-up was 5.6 years. At time of diagnosis a bowel stenosis (S) was documented in 143 patients (37.2%). 130 patients underwent surgery, 62 (48%) for obstruction, 18 (14%) for a perforating complication, 12 (9%) for both obstructing and perforating complication and 38 (29%) for intractable disease. The cumulative rates of surgery were calculated using lifetable analysis. The presence of a stenosis at the time of initial diagnosis was a risk factor for the likelihood of surgery overall [65% (S) vs. 40% (no S) after 10 years; P < 0.001] and of surgery for obstruction [70% (S) vs. 34% (no S); P < 0.001] but did not increase the likelihood of a perforating complication [24% (S) vs. 29% (no S); n.s.]. A perforating complication requiring surgery may therefore not be predicted by the mere diagnosis of a stenosis. Prophylactic surgery of stenotic lesions in patients with Crohn's disease to prevent the development of a perforating complication therefore is not recommended.

Adult↗
PubMed1993

Endoscopic laser therapy in the tracheobronchial system.

Their physical properties make lasers ideal instruments for endoscopic surgical procedures in the narrow tracheobronchial system. By the thermal effects of the Nd-YAG laser, pathological benign and, especially, malignant lesions can be destroyed under direct vision. Working without contact with the tissue, sparing the risk of bleeding and further mechanical obstruction the laser has replaced mechanical and electrical devices and cryoprobes in interventional bronchoscopy to a large extent. Thus many patients with benign lesions can be spared the risk of major thoracic surgery of the large airways. To patients suffering from tumours of the central airways the chance of long-term palliation can be given by resolution of life-threatening complications. Furthermore, by photodynamic laser therapy after application of haematoporphyrin derivatives some patients may even be cured.

Bronchial Diseases↗
PubMed1993

Injury to cultured liver endothelial cells during cold preservation: energy-dependent versus energy-deficiency injury.

Previously, we demonstrated an energy-dependent injury to cultured liver endothelial cells during cold incubation in University of Wisconsin (UW) solution. Here, the effects of Histidine-Tryptophan-Ketoglutarate (HTK) and Euro-Collins (EC) solutions on these cells were studied. In HTK solution, 83% +/- 4% of the cells had lost viability after 9 h of incubation at 4 degrees C. The addition of cyanide (1 mM) to simulate hypoxic conditions protected the cells to the extent that only 9% +/- 1% of the cells lost viability over the same period; the addition of glucose (10 mM) led to increased cell injury. ATP levels were highest in the incubations with the most rapid loss of viability. In Krebs-Henseleit buffer and EC solution, in contrast, cell injury increased upon addition of cyanide; the addition of glucose to Krebs-Henseleit buffer decreased injury. We conclude that the injury to cultured liver endothelial cells during cold incubation in HTK solution is energy-dependent, as it is in UW solution, whereas cells behave differently in EC solution and Krebs-Henseleit buffer.

Adenosine Triphosphate↗
PubMed1993

Preserved incretin effect in type 1 diabetic patients with end-stage nephropathy treated by combined heterotopic pancreas and kidney transplantation.

Insulin secretion is stimulated better by oral than by intravenous glucose (incretin effect). The contribution of the autonomic nervous system to the incretin effect after oral glucose in humans is unclear. We therefore examined nine type 1 diabetic (insulin-dependent) patients with end-stage nephropathy, studied after combined heterotopic pancreas and kidney transplantation, and 7 non-diabetic kidney recipients (matched for creatinine clearance and immunosuppressive medication). The release of gastric inhibitory polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) immunoreactivity and B cell secretory responses (IR insulin and C-peptide) to oral (50 g) and "isoglycaemic" intravenous glucose (identical glycaemic profile) were measured by radioimmunoassay. The difference in B cell responses between the two tests represents the contribution of the enteroinsular axis to the response after oral glucose (incretin effect). Insulin responses after the oral glucose challenge were similar in the two patient groups despite systemic venous drainage of the pancreas graft in the pancreas-kidney-transplanted group. In both groups GIP and GLP-1 increased after oral but not after intravenous glucose, and B cell secretory responses were significantly smaller (by 55.2 +/- 7.7% and 46.5 +/- 12.5%, respectively) with "isoglycaemic" intravenous glucose infusions. The lack of reduction in the incretin effect in pancreas-kidney-transplanted patients, whose functioning pancreas is denervated, indicates a lesser role for the nervous system and a more important contribution of circulating incretin hormones in mediating the enteroinsular axis in man.

Adult↗
PubMed1993

Energy-dependent injury to cultured sinusoidal endothelial cells of the rat liver in UW solution.

The critical injury to liver during cold preservation is believed to occur to the sinusoidal endothelium. In this study the viability of cultured sinusoidal endothelial cells from rat liver was assessed during storage in University of Wisconsin solution at 4 degrees C. The vast majority of cells (83 +/- 12%) died within 24 hr of storage. Addition of KCN (1 mM) to the solution to simulate hypoxia markedly increased survival: only 3 +/- 2% of cells had lost viability after 24 hr in the presence of cyanide. Further experiments showed that other inhibitors of mitochondrial ATP formation (antimycin A 1 microM, rotenone 1 microM, oligomycin 10 microM, carbonyl cyanide m-chlorophenylhydrazone 1 microM) were protective as well, whereas glucose (10 mM) greatly diminished the protective effect of cyanide (loss of viability 38 +/- 7% after 24 hr). ATP measurements confirmed the correlation between the energy state of the cells and cell death: ATP levels after 6 hr of incubation were 19.9 +/- 4.0 nmol/10(6) cells in UW solution, 13.7 +/- 2.9 nmol/10(6) cells in UW + glucose, 6.9 +/- 1.9 nmol/10(6) cells in UW + KCN + glucose and 1.9 +/- 1.5 nmol/10(6) cells in UW + KCN. In contrast to the protective effect observed in UW solution, addition of KCN to Krebs-Henseleit buffer led to increased endothelial cell damage upon cold storage. We therefore conclude that in UW solution damage to the sinusoidal endothelium is energy-dependent.

Adenosine↗
PubMed1993

[Endoscopic surgery of the upper gastrointestinal tract].

Clinical application of laparoscopic cholecystectomy was followed by a lot of other endoscopic procedures for the surgical treatment of diseases of the upper gastrointestinal tract. In cases of disorders of esophageal motility traditional procedures can be performed endoscopically. Remarkable experiences were published concerning the cardiomyotomy, and fundoplication. Endoscopic operations could be shown to be a suitable treatment of benign and malignant tumours of the esophagus. Also the nowadays very rarely indicated vagotomy can be performed laparoscopically having good results. During the last year a few new operations could be added by using endoscopic linear staplers for resections and anastomoses such as gastostomies, jejunostomies, gastroenterostomies and even BII resections. In general surgeons are enabled to perform a great variety of procedures by the use of endoscopic techniques.

Equipment Design↗