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Biomedical subjects

E B Keeffe

Publications and source records attributed to E B Keeffe.

158 records · Page 9Linked to original sources
PubMed1979

Validation of a recording spectrophotometric method for measurement of membrane-associated Mg- and NaK-ATPase activity.

Conventional methods for determination of membrane-associated Mg- and NaK-ATPase activity typically involve a timed incubation of enzyme with ATP followed by measurement of released Pi. They are time-consuming, require a large amount of enzyme protein, and show considerable variability induplicate samples. These problems can be largely eliminated with a coupled enzyme assay in which formation of ADP by ATPase is coupled to NADH oxidation with the intermediate enzymes PK and LDH and the intermediate substrate phosphoenolpyruvate present in excess. NADH oxidation is continuously recorded at 340 nm, and NaK-ATPase represents the ouabain suppressible fraction of total ATPase. This method allows accurate determinatin of initial reaction rates which vary linearly with respect to enzyme protein. Furthermore, it eliminates the need to measure Pi and prevents accumulation of inhibitory ADP. In over 100 preparations of LPM prepared from rats pretreated with agents known to alter ATPase activity or exposed in vitro to ATPase inhibitors. ATPase activity by the coupled-enzyme assay paralleled results obtained with the conventional method. Moreover, the coupled-enzyme assay required less membrane protein, showed less variability in duplicate samples, required half the time, and also yielded accurate values in brain, kidney, and heart tissue. This improved assay should find broad application in the study of membrane ATPase as they relate to a variety of cellular functions.

Adenosine Triphosphatases↗
PubMed1974

Pseudomembranous enterocolitis. Resurgence related to newer antibiotic therapy.

Six patients with pseudomembranous entercolitis were seen at one institution over a six-month period. Clindamycin therapy preceded the diagnosis in all six patients and possibly caused the disease in five cases. Common clinical features included diarrhea, abdominal pain, fever, leukocytosis, radiographic findings of large bowel dilatation with mucosal thickening and a characteristic sigmoidoscopic or gross pathologic demonstration of discrete yellow-white plaques on an otherwise normal mucosa. Complications included toxic megacolon and sigmoid colon perforation. Two of the six patients died. The literature since 1970 is tabulated to clarify the clinical and pathological features of pseudomembranous enterocolitis associated with newer antibiotic therapy. Lincomycin and clindamycin are strongly implicated in the recent resurgence of this formerly rare variety of colitis.

Adult↗
PubMedDate not supplied

Impact of transjugular intrahepatic portosystemic shunt on orthotopic liver transplantation.

Transjugular intrahepatic portosystemic shunt (TIPS) is being increasingly utilized prior to liver transplantation for portal hypertensive bleeding refractory to sclerotherapy or as initial management of variceal bleeding. The impact of TIPS on subsequent orthotopic liver transplantation (OLT) is uncertain. The purpose of this study was to analyze the effect of TIPS on OLT in terms of operative transfusion requirements, operative time, length of hospital stay, and graft and patient survival. The results in 17 patients undergoing TIPS for control of initial or recurrent variceal bleeding prior to OLT between June 1991 and December 1992 were compared to two other groups undergoing transplantation: 32 control patients with a history of variceal bleeding not treated by TIPS and 11 patients with a previous surgical portosystemic shunt. Compared with control and surgical shunt patients, patients who underwent TIPS had less transfusion requirement for packed red blood cells and fresh frozen plasma during OLT. The operative time and hospital stay of the TIPS patients were slightly, but not significantly, less. In contrast to patients having TIPS, the patients with a history of a previous surgical shunt had an increased requirement for packed red blood cells, longer operative time, and longer stay in the intensive care unit and hospital. Two patients had recurrent variceal bleeding after TIPS; one patient was found to have an occluded stent, and the other patient (with a patent stent) responded to sclerotherapy. Of the 14 patients with ascites, 8 patients improved and 6 patients had complete resolution after TIPS. There were no major complications related to TIPS, although 3 patients had new or recurrent hepatic encephalopathy that was easily manageable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Diabetic gastroparesis.

Diabetic gastroparesis is a common, underrecognized disorder affecting both type I and type II diabetics usually in the setting of other diabetic complications. The pathogenesis of diabetic gastroparesis is poorly understood, but autonomic neuropathy appears to play a major role. The symptoms of gastroparesis are nonspecific, and complications such as hypoglycemia and bezoar formation due to gastric stasis may occur. Diabetic gastroparesis can be assessed by measuring the gastric emptying of solid radiopaque markers or by scintigraphy. Treatment approaches include optimizing glycemic control and the use of prokinetic agents. Combination therapy or the alternating use of prokinetic agents may prove to be beneficial in dealing with drug tachyphylaxis.

Diabetes Complications↗
PubMedDate not supplied

Diagnosis and treatment of primary biliary cirrhosis.

Primary biliary cirrhosis (PBC) is a chronic cholestatic liver disease that predominantly occurs in middle-aged women of various ethnic and racial populations. The disease slowly progresses over decades and is supposed to be caused by immune reactions against host antigens. Histologically, it is characterized by inflammatory destruction of intrahepatic small bile ducts, subsequent fibrosis, and finally liver cirrhosis. It is more frequently diagnosed now than in the past probably because of a greater awareness of the disease. There is only week association of PBC with genetic markers. Liver function tests reveal an elevation of serum alkaline phosphatase and gamma-glutamyl transpeptidase levels with or without elevated aminotransferase levels. The hallmark of the disease is the presence of antimitochondrial antibodies (AMAs), which are found in 95% of patients with PBC. AMAs have been shown to be directed against the 2-oxo-acid dehydrogenase complexes located on the inner membrane of the mitochondria. However, AMA titers do not correlate with the disease severity of progression, and the role of AMAs in the pathogenesis of PBC has not been shown. The disease is frequently associated with other autoimmune diseases, including Sjögren's syndrome, scleroderma and thyroid disorders. Most therapeutic efforts have been directed at altering the immune response. Ursodeoxycholic acid (UDCA) appears to be effective therapy in preventing or delaying the need for liver transplantation and improving survival. However, a number of patients receiving UDCA still develop progressive disease and go on to transplantation, which is an effective therapy at the end stage of the disease. Various prognostic models have been proposed to estimate the survival probability and assist in the determination of the optimum timing of liver transplantation.

Autoantibodies↗
PubMedDate not supplied

1989 A/S/G/E survey of endoscopic sedation and monitoring practices.

Monitoring practices for conscious sedation during gastrointestinal endoscopic procedures are not standardized. A questionnaire was sent to 509 randomly selected A/S/G/E members to define current national sedation and monitoring practices. Responses were returned by 290 members (57%) from 45 states. The average respondent was between 35 and 54 years of age and had 12.4 years of endoscopic experience. Excluding flexible sigmoidoscopy, most patients were routinely sedated for endoscopic procedures. Meperidine (87%), midazolam (73%), diazepam (49%), and naloxone (30%) were the drugs most often used during conscious sedation. When a minor tranquilizer was used, midazolam (62%) was used more often than diazepam (38%). Cardiopulmonary sedation-related complications had a low annual occurrence rate of less than 0.5%. Most endoscopists monitor vital signs before and after procedures (greater than 90%) but less often during procedures (77%). Pulse oximeters and electrocardiographic monitoring were used by 65% and 55% of endoscopists, respectively. Electronic monitoring was used more often for patients undergoing endoscopy in hospitals (99.5%) than in private offices (27%). Fifty-four percent of respondents reported that they had a written endoscopy unit policy concerning conscious sedation. Among endoscopists and gastrointestinal assistants, basic life-support certification was common (76% and 77%, respectively), but advanced cardiac life-support was far less common (30% and 18%). This survey found the use of intravenous conscious sedation for gastrointestinal endoscopic procedures to be safe. Monitoring of patients with vital signs is used regularly; moreover, the majority of endoscopists now also employ electronic monitoring equipment.

Adult↗