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Biomedical subjects

B J Hering

Publications and source records attributed to B J Hering.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Combined liver-islet transplantation after epigastric exenteration in carcinoma of Vater's ampulla].

A 44 year old female underwent an upper abdominal exenteration because of an adenocarcinoma of the pancreas with liver metastases (T1 N1 M1). Reconstruction was performed by orthotopic liver transplantation and intraportal islet transplantation. Due to initial non function of the first liver graft, a second liver transplantation was performed. Thereafter, the patient received 375,000 islet equivalents of the primary liver donor in addition to 295,400 islet equivalents of another donor. Six months postoperatively, the patient is off insulin except irregular injections of 4-6 units of insulin to protect her from hyperglycemia after lunch. CT scans of the liver do not show any signs of tumor recurrence. Upper abdominal exenteration with consecutive islet transplantation offers a good method of reconstruction after radical surgery in the upper abdomen. The oncological aspects of the procedure have to be further investigated.

Adenocarcinoma↗
PubMed1994

The effect of streptozotocin on the function of fetal porcine and rat pancreatic (pro-)islets.

Streptozotocin (STZ) is a broad spectrum antibiotic with anti-tumor and diabetogenic properties. Although STZ has been studied for many years, the exact mechanism of its diabetogenic action has not yet been fully elucidated. The present study investigated the effect of STZ on both fetal porcine proislets (FPP) and fetal rat islets (FRI) in an attempt to elucidate the diabetogenic effect of STZ on fetal pancreatic beta cells. This study demonstrates that after in vitro exposure of both FPP and FRI for 30 min to 2.2 mM and 4.4 mM STZ, respectively, FPP showed microscopically an intact structure, a spherical shape and a translucent color, while, in contrast, most FRI were disrupted and showed a slight white color with dark centers. Based on these data, we first transplanted FPP and FRI beneath the renal capsules of nude mice. Three to four weeks later, a single dosage of streptozotocin (180 mg/kg) was intravenously administered. Six of the seven nude mice pretransplanted with FPP became diabetic (blood glucose, BG, 308.08 +/- 33.62 mg/dl) within 2-5 days and then gradually achieved normoglycemia 51.56 +/- 7.71 days after STZ injection. After removal of the grafts, all of the six diabetic mice with normoglycemia returned to hyperglycemia (BG > 300 mg/dl). In contrast, all of the five nude mice pretransplanted with FRI persistently maintained hyperglycemia (BG > 300 mg/dl) and died 5 +/- 0.84 days after STZ injection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Large-scale production of Ba(2+)-alginate-coated islets of Langerhans for immunoisolation.

Islet xenografts immunisolated in alginate capsules have been proposed by many groups for clinical islet transplantation. However, diffusion limitations and the total volume of microcapsules required for transplantation are, among other things, factors which have so far prevented successful clinical application. In this study, these problems have been overcome by immobilisation of rat and porcine islets in a Ba(2+)-cross-linked alignate matrix using an air jet droplet generator technique in combination with subsequent density-gradient purification. This procedure leads to high yields of islets coated with a tailored, thin layer of cross-linked alginate which protects the islets against cytotoxic compounds present in human plasma. The recovery of encapsulated rat and porcine islets was about 70%. Empty capsules were nearly completely removed. Using this technique, the total volume of the resulting microcapsules increased only by a factor of about 1.5 compared to the volume of free islets. The technique can be used for large-scale production of coated islets.

Alginates↗
PubMed1994

Expression of the ras-related rab3a gene in human insulinomas and normal human pancreatic islets.

To determine the expression of the small-molecular-weight guanosine 5'-triphosphate (GTP)-binding protein rab3a in human endocrine pancreatic tissue, total RNA was isolated from five different human insulinomas and from normal human islets. The expression of rab3a was analyzed by Northern blots utilizing a 1,300-bp Eco RI fragment of the cDNA coding for human rab3a. As in the brain, a specific transcript of 1,800 bp was detected in all insulinomas, though with varying signal intensity. When the northern membranes were rehybridized with a radioactively labeled insulin probe, a signal was found for all five insulinomas and cells of normal islets. In contrast, normal human islets showed no detectable expression of rab3a. In conclusion, rab3a is expressed to a significant degree in human insulinoma tissue but not in normal islets.

Animals↗