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Biomedical subjects

J W Marsh

Publications and source records attributed to J W Marsh.

At least 19 recordsLinked to original sources
PubMed1992

The requirements for viral entry differ from those for virally induced syncytium formation in NIH 3T3/DTras cells exposed to Moloney murine leukemia virus.

Moloney murine leukemia virus (Mo-MuLV) has the unique ability to infect different cells via either a low-pH-dependent or a pH-independent entry pathway. Only the pH-independent mechanism of Mo-MuLV entry has been associated with Mo-MuLV-induced syncytium formation. We have now identified a transformed cell line (NIH 3T3/DTras) which efficiently forms syncytia when exposed to Mo-MuLV, yet is low pH dependent for Mo-MuLV entry. Treatment of NIH 3T3/DTras cells with chloroquine, an agent which raises endosomal pH, blocks Mo-MuLV entry, but not Mo-MuLV-induced syncytium formation. This demonstrates that fusion which accompanies viral entry and fusion which is responsible for syncytium formation occur as independent processes in these cells. In addition, we determined that neither inherent differences in the Mo-MuLV receptor nor reduced affinity for Mo-MuLV gp70 can account for resistance of NIH 3T3 cells to Mo-MuLV-induced syncytium formation.

3T3 Cells↗
PubMed1992

Immunosuppressants.

The role and pharmacology of a variety of immunosuppressant agents in the gastrointestinal tract and liver are reviewed in this article. Immunosuppressants covered include cyclosporine, corticosteroids, OKT3, antithymocyte globulin, azathioprine, methotrexate, and FK506. Guidelines for the use and complications of immunosuppressants in liver, pancreas, and small bowel transplantations are presented. Controlled and uncontrolled data for use of immunosuppressants in the management of gastrointestinal and hepatic disorders are also described.

Autoimmune Diseases↗
PubMed1991

Bio-techniques for the detection of genetic toxicity in the aquatic environment.

This article reviews the application of sensitive biotechniques in the detection of DNA damage within the aquatic environment as "early warning" indicators of pollution-related genetic toxicity. Bacterial mutagenicity assays have played an important role both in the discovery of mutagens and in the analysis of the ability of aquatic organisms to convert inert substances to reactive genotoxic products. Genetic damage in aquatic species treated with carcinogens has been detected by analysis of DNA adducts, induction of DNA repair, DNA strand breakage and formation of chromosomal aberrations and sister chromatid exchanges. Little information is available on pollution-related DNA damage resulting from field exposure. A 32P-postlabelling technique for the sensitive detection of DNA adducts is a promising development towards this aim and the analysis of changes in oncogene nucleotide sequence in tumour tissue is considered an important future direction.

Animals↗
PubMed1991

Pseudomonas aeruginosa bacteremia in patients undergoing liver transplantation: an emerging problem.

In our institution, Pseudomonas aeruginosa bacteremia appeared to occur with increasing frequency in patients undergoing liver transplantation. We thus conducted a prospective study to define risk factors and outcome in these patients. Over a 19-month period 6% of liver transplants were followed by Pseudomonas bacteremia. The mean age was 46 years (range, 24 to 67 years). The interval between transplantation and onset of bacteremia was 3 to 372 days (mean, 80). The incidence of Pseudomonas bacteremia in liver transplants was three times that of other transplants (heart, lung, kidney). Ninety one percent of infections were nosocomial. Polymicrobial bacteremia occurred in 30% of episodes. The portal of entry was respiratory in 30%, abdominal in 35%, and biliary in 13%. Four patients had recurrent Pseudomonas bacteremia: liver abscess (1), biliary obstruction (2), subhepatic abscess (1). Survival at 14 days was 70%. Survival rates were significantly lower for patients with hypotension, on mechanical ventilators, and increasing severity of illness (p less than 0.05). Survival was higher when bacteremia occurred within the first 30 days after transplantation compared to after 30 days. A large number (43.4%) of Pseudomonas bacteremias occurred after transplant surgery of biliary tract manipulation, while the patient was receiving a prophylactic regimen of cefotaxime and ampicillin. P. aeruginosa is an important pathogen in the liver transplant recipient; prevention may be possible for a subgroup of patients with the use of prophylactic antibiotics with activity against P. aeruginosa.

Adult↗
PubMed1991

Fulminant hepatic failure after repeated exposure to isoflurane anesthesia: a case report.

A previously healthy but obese 26-yr-old woman was diagnosed as having hepatic dysfunction 17 days after the third of three consecutive exposures to isoflurane anesthesia for paranasal sinus surgery. Serum laboratory findings included elevated aminotransferases and bilirubin. Radiographical evaluations showed no evidence of extrahepatic disease. Serological studies were negative for acute viral infections, and serum copper was normal. The patient's condition deteriorated over the ensuing 17 days, with hyperreflexia, hypoglycemia and a rapid fall in serum aminotransferases with a concomitant rise in bilirubin level and prothrombin time despite maximal medical support. The liver volume as shown by computed tomography fell from 1,290 cm3 to 680 cm3 over 6 days. The patient underwent successful orthotopic liver transplantation 25 days after onset of symptoms. Histopathological examination of the resected liver showed submassive and massive necrosis, with a few foci of microvesicular steatosis and ultrastructural evidence of mitochondrial abnormalities. Although we found insufficient evidence to prove that this case was caused by isoflurane anesthesia, the clinical course and histopathological findings are similar to those in hepatic injury caused by halothane anesthesia. Therefore we report this as a possible case of fulminant hepatic failure resulting from isoflurane anesthesia.

Adult↗
PubMed1990

Development of a diphtheria toxin mutant conjugate directed against antigen-specific B cells expressing high affinity surface Ig.

Modification of a mutant diphtheria toxin, possessing reduced binding capacity, with TNP groups resulted in an Ag-toxin conjugate capable of eliminating TNP-specific B cells. Previous experimental approaches to the elimination of Ag-specific B cells have involved the conjugation of Ag to holoricin molecules or ricin A chain. Holoricin conjugates possess efficacy, but display high nonspecific toxicity. A chain conjugates, which appear specific, lack high potency. In developing the diphtheria toxin-based conjugate, we found high potency for target anti-TNP hybridoma cells and for spleen cells isolated from TNP-immunized mice. The similar intoxication of nontarget cells required concentrations approximately three orders of magnitude higher. Additionally, it was found that the TNP-specific agent may have selectively depleted B cells producing high affinity IgG anti-TNP antibodies.

Animals↗
PubMed1990

Hepatic artery reconstruction for hepatic artery thrombosis after orthotopic liver transplantation.

We evaluated the efficacy of reconstruction of the hepatic artery for intraoperative or postoperative thrombosis in orthotopic liver transplantation. Of 37 grafts with artery thrombosis, 13 (35.1%, 6 intraoperative and 7 postoperative) underwent reconstruction of the hepatic artery. The arterial flow was reestablished and maintained in 5 (38.5%) of the 13. Recurrent thrombosis in the other 8 grafts developed 2 to 24 days (mean, 13.8 days) after transplantation. Reconstruction was successful in 50% (4/8) of the adults, compared with only 20% (1/5) of the children. Satisfactory results were obtained when a definitive cause of thrombosis could be identified. We conclude that early recognition and correction of the cause of hepatic artery thrombosis during or after orthotopic liver transplantation, especially in adults, is often a graft-saving and lifesaving procedure worthy of consideration.

Adolescent↗
PubMed1990

Development of colon cancer after liver transplantation for primary sclerosing cholangitis associated with ulcerative colitis.

Between February 26, 1981, and July 30, 1987, 36 patients underwent orthotopic liver transplantation for primary sclerosing cholangitis associated with ulcerative colitis. Three of the 36 recipients died within 3 mo because of graft nonfunction or surgical complications. The other 33 (92%) lived for at least 1 yr. Two of the 33 died after 12 and 14 mo, respectively, of recurrent cholangiocarcinoma that was not diagnosed before transplantation. Four other patients died of recurrent liver failure (three cases) or immunoblastic sarcoma (one case) after 14, 21, 36 and 44 mo. Twenty-seven (75%) of the patients are still alive 23 to 81 mo after transplantation. Two patients have been diagnosed as having colorectal cancer 11 and 21 mo respectively, after transplantation, for an overall incidence of 5.6% (2 of 36) and a corrected incidence of 6.5% (2 of 31) if the three early deaths and two later deaths caused by cholangiocarcinomas are excluded. It is not known whether colorectal malignancies were present but undetected at the time of transplantation or whether they developed afterward. It is clear that patients who undergo liver transplantation for primary sclerosing cholangitis associated with ulcerative colitis should have careful follow-up of the colon, including colonoscopy and multiple biopsies of the colorectal mucosa. Whether proctocolectomy should be considered prophylactically after liver transplantation is an unresolved issue.

Adenocarcinoma↗
PubMed1990

Analysis of surgical complications after 397 hepatic transplantations.

The results of 397 consecutive orthotopic hepatic transplantations in 333 recipients were reviewed. One or more surgical complications developed in 172 of 323 patients (55 per cent), excluding ten intraoperative deaths. The six month mortality rate among the patients with surgical complications (55 of 172; 32 per cent) was statistically higher than that among patients without such complications (16 of 151; 11 per cent) (p less than 0.001; chi-square, 58.36). Surgical complications included exploratory laparotomy for bleeding or infection in 74 (22 per cent), reconstruction of the bile duct for biliary obstruction or leakage in 55 (17 per cent), external biliary drainage for biliary leakage in four (1 per cent), tracheostomy in 80 (24 per cent), thoracotomy in 12 (4 per cent) and splenectomy in seven (2 per cent). The incidence of biliary obstruction (16 per cent mortality rate) and leakage (48 per cent mortality rate) was 18 per cent (34 of 193) and 2 per cent (four of 193) each after choledochocholedochostomy, which was 3 per cent (five of 187) and 9 per cent (17 of 187) each after choledochojejunostomy. Biliary obstruction (16 per cent mortality rate) was more common after choledochocholedochostomy (p less than 0.005; chi-square, 23.01), whereas the incidence of more serious biliary leakage (48 per cent mortality rate) was higher after choledochojejunostomy (p less than 0.005; chi-square, 8.97). It is concluded that orthotopic hepatic transplantation remains an unforgiving extensive surgical procedure, in which choledochocholedochostomy remains the first-choice reconstruction of the biliary tract because of its lower mortality.

Adult↗
PubMed1989

Cellular processing of a ricin-antibody conjugate. A kinetic analysis of the rate-limiting step.

Upon exposure to holoricin-antibody conjugates, target cells display a period of no measurable intoxication followed by a concentration-dependent exponential decline in protein synthesis. The rate of this decline is increased by conjugate structural variables such as addition of a second ricin to the antibody or introduction of a peptide spacer between the toxin and antibody. Additionally, the rate is enhanced by the addition of ammonia or monensin. The relationship between immunotoxin concentration and the rate of protein synthesis inhibition is shown to obey typical Michaelis-Menten kinetics. By displacing bound immunotoxin with native antibody, it was demonstrated that the rate-limiting saturable process is not due to antibody-surface antigen interaction. Although addition of a second ricin as well as addition of ammonia elevated the measured rate of protein synthesis inhibition, curve-fitting techniques indicated that they did not elevate the maximal rate; however, introduction of a peptide spacer into the conjugate or addition of monensin increased the maximal rate of this saturable process. Additionally, the kinetic examination of the potentiation effects of ammonia and monensin indicates that they operate on different cellular processes involved with the intracellular routing toward intoxication. An equational model is developed which helps interpret the known features of the conjugate intoxication process.

Ammonia↗
PubMed1989

Biliary tract complications in orthotopic adult liver transplantation.

In a series of orthotopic liver transplantations performed between April and August 1987 at the University of Pittsburgh, the monofilament absorbable suture polyglyconate was compared with a braided absorbable suture, polyglactin 910, for its biliary complication rate over a 6-month postoperative period. Complications that were suture-related (obstruction or leak from the anastomotic site) occurred in 1 of 21 transplantations in the polyglyconate group compared with 8 of 26 in the polyglactin 910 group (p = 0.02). Even though the patient sample was relatively small, it appears that the type of suture used for the biliary anastomosis directly correlates with the outcome. A larger patient trial could confirm these initial results.

Anastomosis, Surgical↗
PubMed1989

Change in hepatic function, hemodynamics, and morphology after liver transplant. Physiological effect of therapy.

Orthotopic liver transplantation (OLT) has become standard therapy for patients with acute hepatic necrosis and end-stage liver disease. This study measured change in hepatic function (galactose elimination capacity [GEC]), liver blood flow (low dose galactose clearance: flow), hepatic volume (CT scan; volume) and morphology after OLT. The aim was to measure the physiologic response after OLT and compare this response with that after selective shunt (SS) and sclerotherapy (ES) to determine which patients should receive specific therapy. Between January 1987 and November 1988, 37 patients underwent OLT. Operative mortality was 18%, which was similar to that of SS in Child's C cirrhotics. GEC and volume were less in transplant patients than in cirrhotics treated with SS or ES. GEC, flow, and volume normalized after OLT; GEC was preserved after ES and SS, but volume decreased. Three preoperative patterns were observed that can aid in selection of OLT candidates. Patients with chronic cirrhosis (chronic active hepatitis; cryptogenic) need OLT when GEC is less than or equal to 225 mg/min and volume is less than or equal to 50% normal. Patients with Budd-Chiari Syndrome require OLT if cirrhosis has evolved. Patients with sclerosing cholangitis and primary biliary cirrhosis qualify for transplants when complications of the portal hypertensive syndrome develop. The studies can also direct therapy for ES failures. Selective shunt is indicated in those patients with stable disease whose GEC is greater than or equal to 300 mg/min and liver volume is greater than 75% normal; OLT is indicated for cirrhotics with GEC that is less than 225 mg/min and liver volume that is less than 50% predicted normal.

Adult↗
PubMed1989

Reversal of hypersplenism following orthotopic liver transplantation.

The purpose of this study was to clarify the effect of orthotopic liver transplantation on hypersplenism. In a 1-year period from July 1, 1986 to June 30, 1987, 196 adult patients underwent 233 orthotopic liver transplantations. Of the 58 patients with hypersplenism who were analyzed in this study, hypersplenism was more commonly associated with postnecrotic cirrhosis than other kinds of liver disease (55.3% (47/85) vs. 14.5% (11/76); p less than 0.001). Postoperative platelet counts were statistically higher than preoperative values (p less than 0.05). The latest platelet counts were more than 100,000/mm3 in 53 patients (91.4%). Of the eight patients whose preoperative and postoperative spleen volumes could be compared, all showed the reduction in the spleen size (p less than 0.02). We conclude that orthotopic liver transplantation, which is a radical surgical procedure for portal hypertension, reverses hypersplenism.

Adult↗