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J D Perkins

Publications and source records attributed to J D Perkins.

At least 19 recordsLinked to original sources
PubMed1992

SfiI genomic cleavage map of Escherichia coli K-12 strain MG1655.

An SfiI restriction map of Escherichia coli K-12 strain MG1655 is presented. The map contains thirty-one cleavage sites separating fragments ranging in size from 407 kb to 3.7 kb. Several techniques were used in the construction of this map, including CHEF pulsed field gel electrophoresis; physical analysis of a set of twenty-six auxotrophic transposon insertions; correlation with the restriction map of Kohara and coworkers using the commercially available E. coli Gene Mapping Membranes; analysis of publicly available sequence information; and correlation of the above data with the combined genetic and physical map developed by Rudd, et al. The combination of these techniques has yielded a map in which all but one site can be localized within a range of +/- 2 kb, and over half the sites can be localized precisely by sequence data. Two sites present in the EcoSeq5 sequence database are not cleaved in MG1655 and four sites are noted to be sensitive to methylation by the dcm methylase. This map, combined with the NotI physical map of MG1655, can aid in the rapid, precise mapping of several different types of genetic alterations, including transposon mediated mutations and other insertions, inversions, deletions and duplications.

Base Sequence↗
PubMed1992

Use of ultrasound to detect intestinal wall ischemia in piglets.

To evaluate the use of ultrasound (US) to detect intestinal wall ischemia, we isolated segments of jejunum on single vascular pedicles in five piglets. We sequentially clamped these segments in intervals of 0 to 6 h, reperfused them for 24 h, and then examined them in vitro histologically and with an 8.5 MHz US scan. All segments were grossly viable except those with 6 h of ischemia. Histologically, mild submucosal edema developed after 1 to 2 h of ischemia; after 3 to 4 h, mucosal necrosis, loss of folds, worsening submucosal edema, and prominent neutrophilic infiltration occurred; after 5 to 6 h, severe mucosal necrosis with hemorrhage and submucosal edema was present. Ultrasonically, we saw five wall layers in the control group corresponding to mucosa, submucosa, muscularis propria, and subserosal fat. After mild (1 to 2 h) ischemia, all layers were present except for a discontinuity in layer 3. After moderate (3 to 4 h) ischemia, the five layers persisted but with a markedly thickened submucosal layer, reduced echogenicity, and flattened mucosal folds. With severe (5 to 6 h) ischemia, we observed a loss of all normal layers with no discernible architecture. Using these US criteria, blinded observers were able to differentiate normal/mild from moderate/severe ischemia with a sensitivity and specificity of 100%. These data suggest that US can differentiate, in vitro, normal from moderate and severe degrees of intestinal wall ischemia that correlates well with the histological appearance. Endoscopic US or surgically implantable US probes can potentially help diagnose clinical intestinal wall ischemia.

Animals↗
PubMed1992

NotI genomic cleavage map of Escherichia coli K-12 strain MG1655.

Several approaches were used to construct a complete NotI restriction enzyme cleavage map of the genome of Escherichia coli MG1655. The approaches included use of transposable element insertions that created auxotrophic mutations and introduced a NotI site into the genome, hybridization of NotI fragments to the ordered lambda library constructed by Kohara et al. (BioTechniques 10:474-477, 1991), Southern blotting of NotI digests with cloned genes as probes, and analysis of the known E. coli DNA sequence for NotI sites. In all, 22 NotI cleavage sites were mapped along with 26 transposon insertions. These sites were localized to clones in the lambda library and, when possible, sequenced genes. The map was compared with that of strain EMG2, a wild-type E. coli K-12 strain, and several differences were found, including a region of about 600 kb with an altered restriction pattern and an additional fragment in MG1655. Comparison of MG1655 with other strains revealed minor differences but indicated that this map was representative of that for many commonly used E. coli K-12 strains.

Base Sequence↗
PubMed1992

Cyclic interdigestive pancreatic exocrine secretion: is it mediated by neural or hormonal mechanisms?

Cyclic interdigestive exocrine pancreatic secretion and duodenal motility are closely linked. However, the mechanisms controlling this association are not well understood. The aim of this study was to determine whether a neural or hormonal mechanism controls the temporal association of interdigestive secretion and duodenal motility. In five dogs, the pancreas was autotransplanted to the pelvis with anastomosis of the pancreatic duct orifice to the bladder. Electrodes were positioned to monitor motility patterns of the in situ duodenum. After 10 days, dogs were studied on four occasions during fasting. Pancreatic output of amylase activity continued to cycle, but the periodicity of enzyme peaks (mean +/- SE) was different from the period of the duodenal migrating motor complex (MMC) (60 +/- 3 vs. 125 +/- 7 minutes; P less than 0.05). When grouped according to phase of duodenal MMC, amylase output per 10 minutes during phase I was significantly less than the outputs during phase II or III (135 +/- 52, 214 +/- 78, and 228 +/- 73 x 10(3) U; P less than 0.05). However, there was no temporal relationship of the cyclic output of amylase to duodenal phase III. No differences were found when amylase output was analyzed for the 30 minutes before phase III compared with the 30 minutes after phase III (687 +/- 253 vs. 378 +/- 110 x 10(3) U; P greater than 0.05). Plasma motilin concentrations varied with duodenal MMC, but no relationship existed between plasma motilin or plasma pancreatic polypeptide and peaks in amylase output. This study suggests that the close temporal coordination of interdigestive pancreatic exocrine secretion and duodenal motility is controlled primarily by a neural mechanism.

Amylases↗
PubMed1991

The effect of somatostatin 201-995 on the early course of porcine pancreaticoduodenal allotransplantation.

This study was undertaken to determine the effects of somatostatin 201-995 (SMS) on the maintenance dose of intravenous cyclosporine and on graft blood flow, exocrine secretion, and rejection after porcine pancreaticoduodenal allotransplantation (PDA). For seven days, 12 pigs (6 control, 6 SMS-treated) were studied to determine the effects of SMS on serum CsA concentrations. Twenty-six pigs (14 control, 12 SMS) with streptozocin-induced diabetes underwent PDA. Blood flow was measured through graft celiac and superior mesenteric arteries 15 and 60 min after reperfusion. SMS (75 micrograms s.c.) was given after the 15-min blood-flow measurement in the SMS group. Sixteen pigs (8 control, 8 SMS) were followed postoperatively with daily measurements of serum glucose and amylase concentrations, and urine amylase and trypsin activities. All pigs were immunosuppressed with azathioprine, prednisone, and i.v. CsA. SMS pigs also received SMS (75 micrograms s.c.) every 8 hr. SMS had no effect on maintenance dose of CsA or on serum amylase, urine amylase, or urine trypsin activities. Mean days to rejection were also not affected. Intraoperative graft blood flow was significantly decreased by SMS, but incidence of graft thrombosis was unchanged. These results suggest that in the porcine PDA model, SMS does not appear to inhibit exocrine secretion and potentially may adversely affect the early course of PDA by decreasing graft blood flow.

Animals↗
PubMed1990

Pancreas transplantation at Mayo: I. Patient selection.

From October 1987 to December 1988, 59 patients underwent assessment for combined kidney and pancreas transplantation or pancreas transplantation after receiving a kidney allograft. We report our criteria for accepting candidates for transplantation, the results of the selection process, and the clinical and laboratory profile of those patients who underwent transplantation. Of the overall group, 22 patients (37%) were approved medically, 3 of whom were awaiting financial approval. Of the 59 patients, 15 (25%) were not approved for the transplantation program for medical reasons; in addition, 16 patients declined participation and 3 were not accepted because of lack of financial resources. Medical reasons for exclusion from pancreas transplantation were coronary artery disease in six patients, severe peripheral vascular disease in six patients, other medical problems in two patients, and noncompliance in one patient. Thus, many patients who underwent assessment for pancreas transplantation did not enter the program because of medical, financial, or personal preference reasons. In most cases, the medical reason for exclusion from pancreas transplantation was a cardiovascular disorder.

Adult↗
PubMed1990

Pancreas transplantation at Mayo: II. Operative and perioperative management.

Better perioperative and operative management techniques have contributed to an improvement in the success rate of pancreas transplantation. Because of a shortage of donor organs, the criteria for acceptability of the allograft have been liberalized, and the development of techniques such as combined liver and pancreas procurement has increased allograft availability. Major advances have been made in organ preservation. Currently, pancreas allografts can routinely be stored for 18 to 24 hours. The technique of pancreaticoduodenal transplantation with a duodenocystostomy for the exocrine drainage is widely used. Experience with anesthetic and intensive-care unit management of these patients is accumulating. With the evolution of pancreas transplantation and with the help of the excellent transplant centers in our area, we developed a pancreas transplantation protocol and performed transplantation based on this protocol in 16 recipients at the Mayo Clinic from October 1987 through December 1988.

Adult↗
PubMed1990

Pancreas transplantation at Mayo: III. Multidisciplinary management.

Although pancreas transplantation is a complicated procedure, a good level of success has been achieved because of the introduction of cyclosporine for immunosuppression, improved methods for diagnosing rejection, and a multidisciplinary approach to management. Our immunosuppressive regimen was quadruple therapy with induction by using Minnesota antilymphoblastic globulin. A biopsy technique was instituted in which the pancreas specimens were obtained under cystoscopic direction during episodes of hypoamylasuria. The criteria for rejection episodes were not only biochemical abnormalities but also histologic confirmation and a follow-up to exclude other causes of graft dysfunction. Infectious disease management included use of oral selective bowel decontamination for 3 weeks after transplantation. At the Mayo Clinic between October 1987 and December 1988, 16 patients received pancreaticoduodenal allografts (both kidney and pancreas in 13 and pancreas only in 3 after a prior successful kidney transplantation). In two pancreas and one kidney allograft, function was lost. One patient died of multiorgan failure. The cystoscopically directed biopsy technique was performed 23 times with minimal complications and a 93% success rate. The metabolic results have been excellent; the glycosylated hemoglobulin level was normal 3 to 6 months after transplantation. The quality of life was significantly improved in almost all patients. Nutritional assessment revealed little deterioration after transplantation. With a multidisciplinary approach, the needed answers about the effect of pancreas transplantation on the degenerative complications of diabetes should be forthcoming.

Adult↗
PubMed1990

Persistent centrilobular necroses in hepatic allografts.

A biopsy study of 60 allografts from 53 patients after orthotopic liver transplantation (OLT) revealed prominent centrilobular necrosis (CN) in 18% of the grafts that were suitable for analysis. The lesions often had a "punched-out" appearance, sometimes with unusual features such as giant cell formation. Persistent CN developed 4 weeks to 6 months after OLT, and persisted in two cases for 2 years and longer. In some instances, CN disappeared or healed by scarring. We found no association between CN and rejection arteritis or arteriopathy. Ductopenic (chronic) rejection subsequently occurred in six of eight livers with CN. Overall, patients with persistent CN had a worse prognosis than control patients. A comparison of cases with matched controls failed to reveal significant differences with respect to perioperative factors such as ischemia time, immunologic test results such as lymphocyte crossmatches, drug administration--in particular, of azathioprine, frequency of cellular (acute) rejection or infection episodes, or frequency of complications affecting major hepatic vessels or bile ducts. Morphologic evidence suggests that in some instances, rejection-induced endotheliitis/phlebitis of hepatic vein branches may lead to sinusoidal outflow blockage, sinusoidal dilatation, and dropout of hepatic cell plates. Although potentially reversible conditions such as ischemia or adverse drug reactions are among the possible causes of CN, severe rejection leading to ductopenia appears to be the most important underlying condition. Thus, presence of CN in repeated biopsy specimens from allografts should be considered a warning sign of irreversible rejection.

Adult↗
PubMed1990

Differential diagnosis of hypoamylasuria in pancreas allograft recipients with urinary exocrine drainage.

We have studied the histopathologic correlates of a significantly decreased urinary amylase excretion rate (UAER) to determine its reliability in predicting the presence of cellular rejection within pancreas allografts drained via a duodenocystostomy. Significant hypoamylasuria in pancreas allograft recipients was defined as a diminution of greater than 50% in UAER sustained for greater than 36 hr and not associated with a decrease in serum amylase activity. We observed 18 such episodes of hypoamylasuria in 13 of 18 patients receiving pancreas allografts. Pancreaticoduodenal material was obtained during 11 of these episodes, one attempt failed, and for the remaining 6 episodes we obtained 3 renal allograft biopsy specimens. Histopathologic examination of the 14 specimens revealed cellular rejection in 9 (64%), fibrosis in 2 (14%), enzymatic necrosis in 1 (7%), cytomegaloviral pancreatitis in 1 (7%), and no abnormal features in 1 (7%). During these 14 episodes, a genetically identical renal allograft was present for 11 and showed signs of dysfunction in 9; however, the pancreatic histologic features suggested rejection in only 7 of the 9. Thus even the combination of hypoamylasuria and renal dysfunction in recipients of genetically identical organs was not fully reliable in predicting pancreas allograft rejection. In addition, the interval between organ implantation and onset of hypoamylasuria did not predict the histologic diagnosis. As with other solid-organ allografts, biopsy is a useful adjuvant for determining patient management in the presence of organ dysfunction.

Amylases↗
PubMed1990

Evidence that the soluble interleukin 2 receptor level may determine the optimal time for cystoscopically-directed biopsy in pancreaticoduodenal allograft recipients.

In 18 consecutive pancreaticoduodenal allograft recipients (15 combined kidney/pancreas and 3 pancreas only after a prior successful kidney transplantation) operated on between December 1987 and February 1989, we studied the soluble interleukin 2 receptor (SIL-2R) level over time. All pancreaticoduodenal allografts were transplanted with exocrine drainage via a duodenocystostomy that allowed for cystoscopically directed needle biopsies of the pancreas. Of these 18 recipients, at 6 weeks after transplantation, 6 had had no rejection episodes or cytomegalovirus disease (control group), an acute allograft rejection had developed in 7, CMV disease developed in 4, and both rejection and CMV disease developed in 1 by 12 days after transplantation. SIL-2R level increased in all patients during immunosuppressive induction therapy (preoperative mean +/- SE, 1637 +/- 284 U/mL; maximum, 4367 +/- 687 U/mL). After induction therapy, the mean was 2768 +/- 432 U/mL. In all 6 recipients in the control group, SIL-2R level continued to decrease. However, SIL-2R level was significantly higher compared with controls, in those who had CMV disease (levels were increased at a mean of 7 days before diagnosis of CMV disease) and in those who had acute rejection episodes (levels were increased a mean of 7 days before the clinical diagnosis of rejection). Factors that did not cause an increase in SIL-2R level included acute pancreatitis, wound infection, operative procedures, and CsA nephrotoxicity. SIL-2R level can be useful for monitoring pancreaticoduodenal allograft recipients. Increases predict impending rejection or CMV disease, prior to the onset of organ dysfunction. When SIL-2R level increases, we recommend cultures of blood and urine to exclude CMV and pancreaticoduodenal allograft biopsy to confirm early rejection prior to the initiation of potentially dangerous antirejection therapy.

Biopsy↗
PubMed1990

Pattern of postprandial carbohydrate metabolism and effects of portal and peripheral insulin delivery.

The importance of portal insulin delivery in the regulation of postprandial carbohydrate metabolism is uncertain. To address this question, three groups of dogs were studied: one group in which pancreatic venous drainage was transected and reanastomosed (portal insulin delivery), one in which the pancreatic drainage was transected and anastomosed to the inferior vena cava (peripheral insulin delivery), and one that received only a sham operation. Plasma insulin was greater (P less than 0.05) during peripheral insulin delivery than in either the portal or sham groups, respectively, before and after meal ingestion. On the other hand, C-peptide concentrations did not differ between groups, resulting in a higher (P less than 0.001) insulin to C-peptide ratio in the peripheral group. This indicated that the hyperinsulinemia in the peripheral group was due to decreased insulin clearance rather than increased insulin secretion. Isotopically determined splanchnic uptake of ingested glucose, postprandial suppression of hepatic glucose release, incorporation of CO2 into glucose (a qualitative measure of gluconeogenesis), and total-body glucose uptake were virtually identical in all groups. Similarly, plasma lipid, beta-hydroxybutyrate, and lactate concentrations did not differ between groups. Our data indicate that, despite differences in systemic insulin concentration, portal and peripheral insulin delivery comparably regulate hepatic and extrahepatic carbohydrate metabolism after meal ingestion.

Animals↗