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Biomedical subjects

R L Jenkins

Publications and source records attributed to R L Jenkins.

At least 109 records · Page 6Linked to original sources
PubMed1989

Procurement of a whole pancreas and liver from the same cadaveric donor.

Analogous arterial and portal circulation to the liver and pancreas has heretofore represented an impediment to the simultaneous procurement of a liver and pancreas from the same cadaveric donor. A surgical approach that allows for the retention of sufficient arterial and portal supply to both allografts is described. Variant hepatic arterial anatomy may be technically managed by the use of a donor iliac artery interposition graft.

Adolescent↗
PubMed1989

Perioperative care of the liver transplant patient.

1. Communication among team members on the liver transplant team is crucial; individual responsibilities must be considered while problem solving is shared as a team. 2. A major goal of the OR nurse is to maintain the patient's skin integrity; proper patient positioning and protection is essential. 3. Constant awareness of blood and blood product availability is urgent.

Humans↗
PubMed1988

Demonstration of the adenosine reservoirs with nitrobenzylthioinosine in liver and diaphragm by high-performance liquid chromatography.

Purine nucleotides, nucleosides, nucleobases, dinucleotides and nucleosides derivatives from acid-extracted rat liver and diaphragm were separated and quantitated by reversed-phase ion-pair high-performance liquid chromatography with a mobile phase composed of 90 mM potassium phosphate, 15 mM tetrabutylammonium hydroxide and a 1-30% methanol gradient. During 5 min of ischemia, adenine and guanine nucleotides decreased along with significant declines in NAD and increases in adenosine, inosine, hypoxanthine, xanthine, NADP and adenylosuccinate. Nitrobenzylthioinosine by gavage (5 mg/kg per day for five days) increased adenosine levels but without any alteration in nucleobase levels. Adenosine was shuttled to every available intracellular reservoir which included in declining order of magnitude GDP greater than adenosylhomocysteine greater than adenosine greater than ADP greater than AMP greater than IMP = XMP = GMP.

Adenine Nucleotides↗
PubMed1988

Surgical treatment of biliary cystadenoma. A report of 15 cases.

Mucinous biliary cystadenomas are rare intrahepatic or, less commonly, extrahepatic neoplasms that may produce massive enlargement, hemorrhage, rupture, secondary infection, jaundice, or vena caval obstruction. Radiologic criteria differentiate biliary cystadenomas from more common parasitic or simple cysts. Treatment has included sclerosis, marsupialization, internal drainage, or resection, but without resection the patient is at risk for enlargement, infection, or progression of an unrecognized malignant neoplasm. We report the course of 15 patients who underwent resection for biliary cystadenoma to elucidate the clinical presentation, preoperative evaluation, and surgical treatment. Nine patients had had previous radiologic or surgical intervention other than excision, and complications of sepsis and tumor recurrence had developed. Following complete resection, however, only five postoperative complications were encountered, and no patient experienced recurrence of tumor. Thus, we recommend complete surgical resection as the preferred therapy.

Adult↗
PubMed1988

Association-dissociation studies of bovine and rat liver glutamic dehydrogenase by high-performance liquid chromatography gel filtration.

The concentration-dependent association-dissociation tendency of purified bovine liver and rat liver glutamic dehydrogenase (GDH) has been demonstrated by high-performance liquid chromatographic gel filtration. In the concentration range of 100 to 1.0 micrograms bovine GDH/ml molecular species ranged from dimer and unimer to subunimeric forms. The dissociation process of the unimeric hexapeptide, consisting of six polypeptide chains, to the subunimeric tripeptide, consisting of three polypeptide chains, was irreversible without added ionic support, but reversible with added ionic support. In dilute Tris-HCl bovine liver GDH was dispersed to subunimeric sizes. Increasing the ionic strength in 20 mM phosphate as the mobile phase increased dissociation to a subunimeric tripeptide while sustaining as much as 80% of its activity. Activity of a eluting subunimer was verified by the inclusion of reaction substrates (NAD and glutamute) in the mobile phase and quantification of reaction products (NADH) in chromatograms. Gel filtration of GDH in the presence of GTP with NADH rendered a subunimeric tripeptide, largely independent of ionic strength or GDH concentration. Rat liver GDH, differing from bovine liver GDH, was dissociated by gel filtration to an active tripeptide independent of ionic or buffer conditions.

Adenosine Diphosphate↗
PubMed1988

Myocardial fuel and energy balance, acute ischemia and diabetes.

When glucose-insulin-potassium (GIK) is infused, glucose supplies most of the energy demands of the heart. Fatty acid becomes the major substrate during fasting, pathologically increased work loads or insulin deficiency. Myocardial purine breakdown reflects myocardial energy status and influences coronary tone. Ischemia accelerates breakdown of ATP to AMP, which is further metabolized to adenosine, which causes vasodilatation and a blunted response to catecholamines. If normal circulation is restored, ADP and AMP are rapidly converted to ATP and purine metabolism is changed from degradation to salvage and de novo synthesis of purines. Ischemia impairs mitochondrial function, causing decreased capacity to oxidize fatty acids once aerobic conditions return. Thus, reperfusion with elevated plasma free fatty acids results in acyl-CoA accumulation in the heart. In diabetic animals, phosphorylation of AMP to ATP is defective in the heart, and AMP degradation is increased. Therefore, careful regulation of the blood sugar with concomitant lowering of plasma free fatty acids in diabetics with ischemic heart disease should improve myocardial salvage by preserving and repleting myocardial ATP. Thus, along with reestablishment of coronary flow and reduction in myocardial oxygen demands, may significantly reduce the morbidity of acute ischemia in diabetics.

Acute Disease↗
PubMed1988

Ganciclovir therapy of severe cytomegalovirus infections in solid-organ transplant recipients.

The clinical and virologic efficacy of ganciclovir (9-[1,3-dihydroxy-2-propoxymethyl]guanine) in the treatment of severe CMV infections in solid organ transplant recipients was investigated. Twelve patients (9 liver and 3 kidney transplant recipients) with CMV retinitis, esophagitis, hepatitis, or pneumonia received ganciclovir at a dose of 0.75-7.5 mg/kg/day for 10-30 days (mean duration 17 days). Clinical stabilization or improvement occurred in 8 patients (67%). Serial liver biopsies in 6 liver allograft recipients with CMV hepatitis demonstrated substantial histologic improvement on treatment. Of 6 patients with CMV pneumonia, 4 (67%) recovered and survived. Cultures of blood and other sites became negative in 9 patients (75%). Three patients (25%) had recurrent viral shedding after treatment, but none of these relapsed with invasive infections. Mild neutropenia was the only side effect encountered but was frequent (67%). The overall survival rate was 50%. Ganciclovir is effective in reducing CMV shedding in solid organ transplant recipients and is well tolerated. Our experience suggests a clinical benefit as well in patients with severe, invasive CMV disease. Relapse, in contrast to patients with the acquired immunodeficiency syndrome, is infrequent.

Acyclovir↗
PubMed1988

Paradoxical organ-specific adaptations to streptozotocin diabetes mellitus in adult rats.

Adult male Fisher rats injected with streptozotocin (Stz) to produce diabetes mellitus demonstrated a significant loss of total body weight associated with adipose and muscle tissue wasting. Paradoxically, intestinal mass and length were increased in Stz-treated rats despite catabolism of other tissues. Concomitant with increased intestinal mass, food and water intake increased significantly in Stz-diabetic animals. Renal weight was not reduced despite the fall in total body weight. It is proposed that the adult Stz-diabetic rat responds to a loss of available insulin by polyphagia, polydipsia, and catabolism of adipose and muscle tissue and that a large percentage of available synthetic fuel is devoted to the production of additional intestinal tissue.

Adaptation, Physiological↗
PubMed1988

Adenine nucleotide metabolism in hearts of diabetic rats. Comparison to diaphragm, liver, and kidney.

High-performance liquid chromatography analysis of acid-extracted tissues revealed decreases of high-energy nucleotides and increases in low-energy nucleotides and metabolites in heart, diaphragm, and liver but not in kidneys of diabetic rats. In comparison with nondiabetic rats, the total adenine nucleotide content of diabetic rat heart and diaphragm but not liver decreased, indicating an increase in catabolism of AMP. Maximal initial rates of the AMP catabolic enzymes 5'-nucleotidase, adenosine deaminase, and AMP deaminase were elevated in the hearts of BB/Wistar and streptozocin-induced diabetic rats. Nucleotide salvage enzymes adenylosuccinate synthetase and adenylosuccinate lyase were elevated above normal in the diabetic heart, whereas hypoxanthine-guanine phosphoribosyl transferase was not altered. Cytosolic-to-mitochondrial ratios from maximal initial rates after correction for mitochondrial breakage were increased above controls in diabetic hearts for nucleoside diphosphokinase and aspartate aminotransferase. Nucleotide levels, degradation rates, and substrate compartmentation between cytosol and mitochondria are discussed in relation to concurrent diabetes.

Adenine Nucleotides↗
PubMed1988

Fibrinolysis during liver transplantation in humans: role of tissue-type plasminogen activator.

Human liver transplantation is frequently associated with a coagulopathy and bleeding diathesis developing during the anhepatic phase of surgery. The hemostatic defect has been attributed in part to accelerated fibrinolysis. In this study we evaluated changes in specific blood fibrinolytic parameters occurring in eight adult patients undergoing first-time orthotopic liver transplantation. Five of the eight patients experienced moderate to severe systemic fibrinolysis as reflected by alpha 2-antiplasmin consumption and fibrinogen degradation with the concomitant appearance of fibrin(ogen) degradation products. In association with these changes, an increase in tissue-type plasminogen activator (t-PA) activity and t-PA antigen levels was also observed. Fibrinolysis was most pronounced during the anhepatic phase of surgery and decreased after revascularization of the grafted liver. Three additional patients who underwent the same procedure manifested much less evidence of systemic fibrinolytic activation and had minimal elevation of t-PA antigen levels or activity. Urokinase-type plasminogen activator levels, although elevated in three patients, were disassociated from increased t-PA levels and concomitant systemic fibrinolysis. The operative course of those patients developing t-PA-associated fibrinolysis was characterized by shock, acidosis, generalized bleeding, and a need for substantially greater blood product support during surgery. These findings suggest that the observed fibrinolytic defect is related to increased circulating plasma levels of t-PA, presumably resulting from a combination of increased intravascular release and decreased hepatic clearance of t-PA. These observations may have implications for intraoperative therapy for the transplant-related coagulopathy and its associated bleeding.

Adult↗
PubMed1987

Hepatic cryosurgery with intraoperative ultrasound monitoring for metastatic colon carcinoma.

We utilized cryosurgery with intraoperative ultrasound (IOUS) monitoring in ten patients to treat multiple unresectable hepatic metastases from colorectal carcinoma. The liver was exposed at laparotomy, and tumors were subjected to three cycles of freezing (eight minutes each) and thawing. Freezing was monitored by IOUS, which visualized frozen tumor as a hyperechoic rim with posterior acoustic shadowing. Frozen normal liver appeared hypoechoic after thawing compared with normal unfrozen liver. There were no significant complications. The follow-up ranged from four months to 17 months (median, 7.5 months). Tumor response was documented by pathologic findings (coagulative necrosis), progressive fall of carcinoembryonic antigen levels, and computed tomographic scan evidence of necrosis and shrinkage of tumor. One patient underwent repeated laparotomy five months after cryosurgery and had the frozen lesions resected; there was no residual tumor. This study establishes the technical feasibility and antitumor response of hepatic cryosurgery and the use of IOUS for precise localization and monitoring of cryoablations.

Adult↗
PubMed1987

Amino acid clearance in cirrhosis. A predictor of postoperative morbidity and mortality.

The central plasma clearance rate of amino acids (CPCR-AA), the ratio of peripheral amino acid entry rate into blood plasma to arterial amino acid concentration, was measured preoperatively in 149 noninfected cirrhotic patients. In 50 survivors of shunting or general surgical procedures, the mean (+/- SEM) CPCR-AA was 201 +/- 17 mL/m2/min; in 39 subsequent deaths, the mean ratio was 87 +/- 14 mL/m2/min. Comparing Child's classification with CPCR-AA reveals the following values: class A (mortality, two of ten patients) survivors, 152 +/- 23 mL/m2/min; class A deaths, 96 +/- 54 mL/m2/min; class C (mortality, 13 of 19 patients) survivors, 214 +/- 47 mL/m2/min; class C deaths, 101 +/- 13 mL/m2/min. The preoperative CPCR-AA of 46 patients receiving liver transplants was 91 +/- 9 mL/m2/min; 69% of these patients survived. Preoperative CPCR-AA values correlated significantly with rates of hepatic protein synthesis in incubated liver slices obtained by biopsy at operation in 22 patients. Thus, CPCR-AA determination is a true liver function test, valuable in predicting surgical mortality and selecting transplantation or other operations for cirrhotic patients.

Adult↗
PubMed1987

Surgical approach to generalized lymphadenopathy in homosexual men.

Sixty patients considered at risk for acquired immune deficiency syndrome (AIDS) were referred for evaluation of generalized lymphadenopathy. All patients were seropositive for antibody to human T-lymphotropic virus type III (HTLV-III). Multiple lymph node biopsies from different nodal areas were performed. The results were evaluated in order to see if the diagnostic yield is increased by the performance of multiple lymph node biopsies. In no case was additional diagnostic information provided by performing multiple biopsies. In patients with diffuse lymphadenopathy who are at risk for AIDS, single node excisional biopsy is indicated to rule out opportunistic infection or/and tumor.

Acquired Immunodeficiency Syndrome↗