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Biomedical subjects

D Barr

Publications and source records attributed to D Barr.

At least 55 records · Page 3Linked to original sources
PubMed1990

Histologic diagnosis of rejection by using cystoscopically directed needle biopsy specimens from dysfunctional pancreatoduodenal allografts with exocrine drainage into the bladder.

To determine the histologic features of rejection and to identify nonrejection causes of human pancreatic allograft dysfunction, we analyzed 31 needle biopsy specimens (17 pancreatic, 14 duodenal) obtained under cystoscopic direction from 15 dysfunctional pancreatoduodenal allografts with exocrine drainage into the bladder. Eight allografts undergoing rejection showed the most common histologic features of rejection to be diffuse mixed inflammatory infiltrates of pancreatic acinar tissue and duodenum wall. Diffuse infiltration of pancreatic acinar tissue by neutrophils was the earliest histologic change in rejection. Seven dysfunctional allografts not undergoing rejection ("nonrejection") showed a normal pancreas or various changes including acinar dilation with inspissation of secretions, fibrosis, cytomegalovirus inclusions, and enzymatic necrosis. The histologic changes in the duodenum paralleled those in the pancreas in both rejection and nonrejection allografts. We conclude that the histologic features of rejection in pancreatoduodenal allografts are distinctive. The changes seen in biopsy specimens accurately reflect the state of the graft and can be used to diagnose rejection and to identify other causes of graft dysfunction. Biopsy samples from the duodenum as well as the pancreas are diagnostically useful. The biopsy findings can be used to guide the clinical management of rejection and in the development of other noninvasive tests for rejection.

Biopsy, Needle↗
PubMed1989

Diversion of the gastroduodenal vein: an in situ model of systemic insulin drainage.

A technique of diversion of the gastroduodenal vein in a canine model is described to compare long-term metabolic effects of systemic versus portal pancreatic endocrine drainage. The vein was transected at its entrance into the portal vein and either diverted to the inferior vena cava (systemic group) or reanastomosed to the portal vein (portal group). All remaining venous drainage of the pancreas was interrupted. An additional group of animals underwent laparotomy without manipulation of pancreatic vasculature (sham group). Fasting peripheral insulin and glucose values were determined 3 months postoperatively. Fasting insulin values were significantly higher in the systemic group (mean 10.7 +/- 1.06 U/ml) than in the portal (5.8 +/- 0.70, P = 0.002) and sham (6.4 +/- 0.68, P = 0.01) groups. Fasting glucose values were not significantly different in the three groups. At sacrifice, venous thrombosis was noted in one systemically diverted dog (6.7%). All other anastomoses were patent. No significant collateralization was apparent in any group. No significant complications were noted. This procedure simulates the hormonal milieu created by heterotopic pancreatic transplantation while preserving pancreatic innervation and exocrine function, and serves as an excellent model for investigating the effects of systemic hyperinsulinemia on protein, carbohydrate, and lipid metabolism.

Animals↗
PubMed1989

Sequential histopathologic changes in pancreaticoduodenal allograft rejection in dogs.

To determine the nature and sequence of the histologic changes in the early rejection of pancreaticoduodenal allografts and to assess the correlation between pancreaticoduodenal biopsy findings and the pathologic changes in the graft, we performed serial cystoscopically directed needle biopsies of pancreaticoduodenal allografts in 18 dogs and compared the findings with the histologic changes in 16 autografts as controls. Tissue adequate for evaluation was obtained by the biopsy technique in 70% of instances. The earliest and most characteristic manifestation of rejection was diffuse mixed inflammatory infiltrates involving the pancreatic acinar tissue and duodenum. The biopsy findings correlated well with the changes in the resected pancreatic specimens. Cellular rejection in the duodenum correlated with rejection in the pancreatic graft. There were no changes in the autografts that resembled cellular rejection. We conclude that, in the canine model, cystoscopically directed needle biopsy of pancreaticoduodenal allografts consistently provides adequate tissue for the diagnosis of rejection; the status of the graft can be monitored by serial biopsies of pancreatic acinar tissue and, possibly, by serial biopsies of the duodenal wall alone.

Animals↗
PubMed1989

Canine pancreaticoduodenal allotransplantation with cystoduodenostomy: an animal model with clinical application.

Most techniques described in animal models of pancreatic transplantation use either segmental or autotransplants. We employ a technique of pancreaticoduodenal allotransplantation in the dog that closely resembles the operation used in humans. The arterial supply of the entire pancreatic graft is preserved by procuring a Carrel patch of aorta encompassing the origin of the celiac and the superior mesenteric arteries. Splenic, inferior pancreaticoduodenal, and superior pancreaticoduodenal arteries remain intact with the graft. Venous drainage is through a short segment of portal vein. A 6-cm cuff of duodenum is taken with the head of the pancreas. Engraftment proceeds by placing the allograft within the peritoneal cavity of the recipient. End-to-side vascular anastomoses are constructed to distal aorta and inferior vena cava. The duodenal cuff is anastomosed to the dome of the bladder for drainage and analysis of exocrine secretions and to provide a port of entry for cystoscopically directed needle biopsy. A total pancreatectomy is performed to induce a state of diabetes. The average operating time is 5 h. Twenty-two dogs have undergone allotransplantation using this technique. Six dogs had no complications and were sacrificed after meeting criteria of their study protocol. There were three technical failures, two arterial thromboses and one exsanguination, yielding an 86% rate of successful engraftment. Three other dogs died of intussusception and three dogs died of sepsis, one secondary to wound dehiscence and one due to inadvertent common bile duct ligation during pancreatectomy. Wound problems, four dehiscences and two superficial infections, occurred only in immunosuppressed dogs.

Animals↗
PubMed1984

Factors governing the human immune response to injected insulin.

Seventy-nine patients were observed prospectively during their initial period of treatment with conventional bovine insulins. Insulin antibody levels 6 months after starting insulin therapy did not correlate with age, gender or beta cell function at onset of treatment. Patients who required soluble insulin in addition to isophane insulin developed higher levels of insulin antibody. Patients bearing the HLA-B8, DR3 and C4AQO alleles had lower levels of insulin antibody, whereas those bearing DR7 produced significantly higher levels. Other alleles at the C4A, C4B, C2, factor B or Gm loci did not appear to have a significant effect on insulin antibody production. The hyporesponsiveness of B8/DR3/ C4AQO -positive individuals probably reflects a non-specific abnormality of immunity whereas the enhanced responsiveness of those positive for DR7 suggests the presence of a specific immune response gene for insulin.

Adolescent↗
PubMed1980

A G-band study of chromosomes in liveborn infants.

The results of a chromosome survey of 3993 liveborn infants, the majority of which have been studied using G-banding, are reported. The frequency of all types of chromosome abnormalities detected was similar to that found in previous newborn surveys, which were carried out on different socio-economic structure, but the incidence of aneuploid chromosome abnormalities was comparable in the two localities.

Aneuploidy↗
PubMed1980

The incidence of Gm allotypes in a group of Iraqi Arabs.

Immunoglobulin allotypes were studied in a group of Iraqi Arabs. Results showed that the incidence of the Gm and Km markers investigated fall into the ranges quoted for Caucasian populations, except for the G3m(t) factor which was shown to have an incidence higher than that found in Caucasian groups.

Hemagglutination Inhibition Tests↗
PubMed1969

Externally suppressible frameshift mutant of Salmonella typhimurium.

Prototrophic revertants of ICR-191A-induced frameshift mutant hisD3018 have been induced spontaneously by ICR-191A and N-methyl-N'-nitro-N-nitrosoguanidine (NG) treatment. In each case two genetically distinct prototroph classes were differentiated by transducibility into his deletion recipients: (i) transducible, generally fast-growing revertants within the hisD gene producing from 10 to 100% of normal amounts of histidinol dehydrogenase and (ii) nontransducible slow-growing prototrophs with very low levels of enzyme activity of which at least some arose by external suppression. These nontransducible revertants, whether arising spontaneously or in the presence of ICR-191A or NG, contain histidinol dehydrogenase which is electrophoretically similar to the wild-type enzyme.

Acridines↗