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Biomedical subjects

E M Walker

Publications and source records attributed to E M Walker.

At least 73 records · Page 4Linked to original sources
PubMed1983

Effects of combined treatment with diethyldithiocarbamate and dihydroxyethyldithiocarbamate on distribution and excretion of cadmium.

Diethyldithiocarbamate (DDTC) rapidly mobilizes metallothionein-bound cadmium (Cd) from kidneys, liver, and spleen, but promotes a redistribution which results in higher Cd burdens in lungs, testes, and brain. Dihydroxyethyldithiocarbamate (DHDC) is less potent than DDTC in mobilizing renal Cd, but does not promote Cd redistribution to brain. Combined treatment with DDTC and DHDC, at one-half the molar dose of each when used alone, effected virtually as extensive renal Cd depletion as did DDTC alone, and enhanced slightly Cd mobilization from intestine and testes. Redistribution of Cd to brain was much less after combined treatment than was observed following treatment with DDTC alone.

Animals↗
PubMed1983

Unoperated abdominal aortic aneurysm: presentation and natural history.

The natural history of abdominal aortic aneurysm (AAA) is death from rupture unless the patient dies from another cause prior to rupture. Elective aortic grafting is the treatment of choice. Following rupture, emergency operation is the only treatment which will prolong the patient's survival. Controversy still exists as to the optimum management in poor risk patients and in those with a small aneurysm. This paper describes the presentation and natural history of 65 patients presenting with a ruptured abdominal aortic aneurysm who did not have an emergency operation, and a further 27 patients in whom the diagnosis of intact AAA was made who did not have an elective aortic replacement graft. The correct diagnosis was made at the time of admission in only 43 of the 65 patients with ruptured aneurysms. The diagnostic errors and appropriate investigations in cases of doubt are discussed. The mean time from admission to hospital to death was 8 hours. The reasons for not performing an elective operation in the 27 patients known to have AAA are given. Nine have subsequently died from rupture. There have been 7 deaths from other causes.

Aged↗
PubMed1983

Removal of common bile duct stones after emergency drainage of the gall bladder.

Because of the hazards associated with cholecystectomy and choledochotomy in acute biliary tract disease, cholecystostomy may be performed as an emergency procedure. Postoperative tube cholangiography in such patients may show calculi in the biliary ducts. The percutaneous extraction of these calculi prior to cholecystectomy simplifies the elective surgical procedure.

Cholangiography↗
PubMed1981

Management of sickle hemoglobinopathies in pregnant patients.

During the past decade, pregnancy outcome has improved among patients with sickle hemoglobinopathies. The role of prophylactic exchange transfusion in this improvement is uncertain. This study reviews the experience in 64 pregnancies managed at the Medical University Hospital over a 7 year period. Prophylactic exchange transfusion was not associated with improved pregnancy outcome and was associated with significant antibody formation. Exchange transfusion may best be reserved as a treatment modality when infection, crisis, or symptomatic anemia occurs in patients with a sickle hemoglobinopathy.

Anemia, Sickle Cell↗
PubMed1981

Effects of prolonged exposure to dietary DDT and PCB on rat liver morphology.

Livers from mature female rats exposed for up to 36 weeks to dietary levels of Aroclor 1242 (75 or 150 ppm) and/or commercial grade DDT (75 to 150 ppm) were compared to those from animals receiving basal diets. In earlier studies, reproductive effects of the test substances were assessed. Moreover, the markedly abnormal gross appearance of the livers led to examination of the hepatic effects of PCB and DDT in more detail, at both the light microscope (LM) and electron microscope (EM) levels. Light microscopy revealed focal liver cell necrosis in rats fed PCB, DDT, and PCB-DDT combinations. Higher levels of PCB (150 ppm) increased the severity of necrosis. Feeding both DDT and PCB produced similar effects at 75 ppm, and caused atypical centrolobular regeneration, occasionally forming nodules, resembling small tumors. The experimentally induced injury was associated with the marked accumulation of iron-containing pigment in hepatocytes and Kupffer cells. Electron micrographs demonstrated the presence of whorl structures (myelin figures) within liver cell cytoplasm, and for the first time clearly illustrated the endocytotic expulsion of these membranous whorls from hepatocytes into the bile canaliculi and sinusoids. Other ultrastructural changes were similar to those previously reported in rats livers injured by several hepatotoxic substances. Mitochondria enclosed by or projecting into large non-lipid vacuoles were present in several experimental groups. The electron micrographs provide the most convincing evidence to date to support the hypothesis that myelin figures may be the vehicle whereby the cells rids itself of specific hepatotoxic substances.

Animals↗
PubMed1980

Automated erythrocytopheresis for sickle cell anemia during pregnancy.

Automated erythrocytopheresis allows for selective removal of erythrocytes from whole blood by means of extracorporeal centrifugation and separation. Remaining cellular and liquid fractions are returned to the patient, along with donor erythrocytes. Supertransfusion with the use of plasmapheresis and simultaneous direct transfusion of erythrocytes increases the hematocrit while maintaining stable intravascular volume. This technique was used in the prophylactic exchange transfusion in eight pregnant women with sickle hemoglobinopathies. Two patients required repeat procedures 7 and 13 weeks later for hemoglobin A concentration or hematocrit less than 25%. The results from the first five pregnancies are detailed. All pregnancies were carried to term, with the delivery of healthy infants. There was no fetal or neonatal morbidity, and the only maternal morbidity was a case of puerperal endometritis. Erythrocytopheresis has been established as a flexible and useful means of managing gravid patients with sickle hemoglobinopathies.

Anemia, Sickle Cell↗
PubMed1980

Conjunctival lesion caused by Rhinosporidium seeberi.

We have described the first known reported case of rhinosporidiosis from the state of South Carolina and possibly the ninth reported conjunctival infection in the United States. Differential diagnosis of focal lesions on the conjunctiva, eyelid, or sclera includes cystic inclusions or adenoma of the various glandular structures, pterygium, pedunculated granuloma due to retained foreign body, or end-stage chalazion. Histopathologic differential diagnosis includes spherules of Coccidioides immitis.

Adult↗
PubMed1979

Cholestyramine in the peritoneal cavity of the rat.

The effects of cholestyramine in the peritoneal cavity of the rat are described. Cholestyramine causes mild peritonitis with adhesion formation between the liver and the omentum. In the management of biliary peritonitis, a lavage solution containing a suspension of cholestyramine would appear to be contra-indicated by these experimental studies.

Animals↗
PubMed1979

Hemochromatosis caused by excessive vitamin iron intake.

Rare cases of hemochromatosis have been reported in patients who underwent prolonged oral iron therapy for hemolytic anemia or prolonged self-treatment with iron pills. A proportionately large segment of the South African Bantu tribe, who ingest large quantities of an alcoholic beverage brewed in iron pots, are found to have the disease. Reports of health fadists developing hemochromatosis due to excessive dietary iron intake, however, are extremely rare. This report presents clinical considerations and pathologic findings in a compulsive health fadist who consumed large numbers of vitamins containing iron. Clinical findings included the development and progression of cirrhosis of the liver, bronzing of the skin, and diabetes mellitus, all consistent with a diagnosis of hemochromatosis. Light microscopy of liver biopsies taken late in the course of the disease revealed a massive buildup of iron in the hepatocytes, less in the Kupffer cells, and sparse deposition in the epithelial cells of the bile duct. Minimal periportal fibrosis was noted. Electron microscopy showed numerous pleomorphic siderosomes with varying degrees of crystallization and ferritin attached at uniform intervals to the membranes of residual bodies. Abundant free ferritin was observed in most cells. The aggregated and membrane-associated ferritin was verified by non-dispersive x-ray analysis. An additional finding, noted only by electron microscopy, was the presence of many fat-storing cells of Ito, which are thought to be involved in the onset of fibrosis.

Cytoplasmic Granules↗
PubMed1979

Some aspects of the epidemiology of equine babesiosis.

The sex, coat colour, age, province and month of occurrence of every case of babesiosis was recorded in a horse population of 5856 in South Africa and Rhodesia. A total of 115 cases were recorded during the period 1973-01-01 to 1973-12-31. Chisquared tests were used to evaluate the significance of frequencies. Significant biases in the distribution of cases of babesiosis were found with regard to season (P < 0,05), sex (P < 0,001) and coat colour (P < 0.01).

Animals↗
PubMed1978

Relationship of the constituents of bile to biliary peritonitis in the rat.

The local action of bile salts has been associated with a wide variety of gastrointestinal diseases. This paper describes an animal model to determine which of the major solid components of bile are responsible for peritoneal destruction in biliary peritonitis. In the rat, bile salts within the peritoneal cavity cause peritonitis but cholesterol and lecithin are without deleterious effect.

Animals↗
PubMed1978

Effects of blood, bile and starch in the peritoneal cavity of the rat.

The reaction of rat peritoneum to the intraperitoneal injection of rat blood, human bile, starch glove powder, and a suspension of starch in blood or bile was examined by histological section and en face microscopy of the peritoneal surface (Häutchen technique). Haemoperitoneum causes little destruction of the peritoneum, but bile produces some peritonitis with a purulent exudate and destruction of subperitoneal muscle. Starch granulomas form following intraperitoneal injection of glove powder, though 0.1 g is insufficient to produce adhesions. The addition of starch to blood or bile enhances the peritonitis and delays healing. These results indicate that bile and starch should not be left in the peritoneal cavity at the end of surgical procedure.

Animals↗
PubMed1977

Some effects of dieldrin and mirex on Ehrlich ascites tumor cells in vivo and in vitro.

The effects of dieldrin and mirex on Ehrlich ascites tumor cells were assessed, using certain in vivo (in mice) and in vitro measurements. Mirex retarded the development of Ehrlich ascites tumor in vivo, but dieldrin did not. Effects of dieldrin on de nova RNA purine synthesis from formate in vivo were slight, while mirex inhibited the synthesis of both RNA purines. Dieldrin inhibited the in vitro incorporation if thymidine, uridine, and L-leucine into DNA, RNA, and protein, respectively, but mirex was virtually without effect.

Animals↗
PubMed1977

Preparation and antitumor evaluation of water-soluble derivatives of dichloro(1,2-diaminocyclohexane)platinum(II).

The structure of the antitumor agent, dichloro(1,2-diaminocyclohexane)platinum(II) (NSC-194814), was modified by replacing the chlorides with organic or inorganic anions. Eighteen new platinum complexes were so isolated and their antitumor properties against the L1210 leukemia in C57BL/6 X DBA/2 mice were evaluated. Most of the complexes were readily soluble in water and some had enhanced antitumor activity compared to the parent dichloro complex. In addition, increased solubility with retention of significant antitumor activity was obtained by oxidizing the parent dichloroplatinum(II) complex with halogen or peroxide to give two platinum(IV) complexes. Some previously reported platinum complexes with phosphorus, selenium, or tellurium electron donor ligands were also synthesized and assessed for antitumor action, but these did not show appreciable activity.

Animals↗