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Biomedical subjects

J Mitchell

Publications and source records attributed to J Mitchell.

At least 397 records · Page 22Linked to original sources
PubMed1981

Cimetidine prophylaxis for gastric ulcers in laboratory swine.

Bleeding gastric ulcers were a major cause of morbidity and mortality in young swine subjected to surgery, chronic catheterization, and daily experimental manipulation. Some of the animals died suddenly due to exsanguination into the gastrointestinal tract, while others survived for several days following the onset of clinical signs. These signs included dark, tarry stools, lethargy, pale mucous membranes, decreased appetite, and dyspnea. Abnormal clinical laboratory findings included decreased hematocrit, hemoglobin and erythrocyte counts indicative of chronic blood loss anemia. On postmortem examination, single or multiple ulcers of variable sizes were found in the nonglandular cardiac portion of the stomach, and the gastrointestinal tract often contained blood. Histologically, the ulcers had a base of granulation tissue with surface suppuration. Prophylactic treatment of these ulcers was initiated using cimetidine, a histamine II blocker. The drug was administered via the drinking water at 15 mg/kg body weight/day. Fourteen of 62 (22.5%) pigs that did not receive cimetidine developed bleeding ulcers. Of 45 animals given daily prophylactic doses of cimetidine, none manifested clinical signs indicative of a bleeding ulcer. These results indicated that cimetidine was effective in preventing morbidity and mortality due to bleeding gastric ulcers in young swine used in chronic laboratory experiments.

Animals↗
PubMed1980

Primary malignant mediastinal germ cell tumors: a study of three cases.

Three patients with primary malignant mediastinal germ cell tumors are presented and the literature is briefly reviewed. A great disparity exists in the literature regarding the classification and differential diagnosis of these tumors. Resection and irradiation of seminomas give relatively satisfactory results. The prognosis of malignant teratomas, embryonal cell carcinomas and choriocarcinomas is poor, regardless of the mode of treatment.

Adult↗
PubMed1980

Peripheral neuropathy following intraneural injection of mercury compounds.

Between 0.25-25 micrograms of an aqueous solution of either mercuric chloride or methyl mercuric acetate was injected directly into the sciatic nerve of 28 adult Wistar rats. The resultant pathological changes in the nerve were examined by teasing individual fibres and by light and electron microscopy. In most respects mercuric chloride was more toxic than methyl mercuric acetate. The large doses of mercuric chloride produced a hind limb paresis within 24 h but no clinical signs followed injection of organic mercury. The predominant effect of mercuric chloride was on Schwann cells which showed cytoplasmic swelling and necrosis, associated with extensive segmental demyelination. In contrast methyl mercuric acetate caused axonal degeneration in many of the large myelinated fibres but only minor alterations were observed in Schwann cells.

Animals↗
PubMed1980

Nefopam and propoxyphene in episiotomy pain.

To evaluate relative efficacy, safety, and time course of analgesia, nefopam (45 and 90 mg), a new centrally acting nonnarcotic analgesic, was compared with propoxyphene (65 mg) and placebo in a single oral dose, parallel, stratified, randomized, double-blind trial with 100 hospitalized postpartum women with medium or severe episiotomy pain. Using subjective reports as indices of response, patients rated pain intensity and side effects at periodic interviews for 6 hr. After 45 and 90 mg nefopam, 21 of 25 and 20 of 25 patients (p less than 0.01) reported more than 50% reduction of pain, whereas after 65 mg propoxyphene 18 of 25 (p less than 0.05) and after placebo 11 of 25 reported reduction in pain. Relative efficacy, based on summed pain intensity differences, showed measurable but modest dose-dependent analgesia with nefopam, suggesting that the effectiveness of 65 mg propoxyphene lay between 45 mg nefopam and placebo. Side effects included mild dizziness and hypothermia after nefopam and mild elevation of diastolic arterial pressure after nefopam and propoxyphene. Our results suggest that 45- and 90-mg doses of nefopam induced more analgesia than 65 mg propoxyphene in the relief of episiotomy pain.

Adolescent↗
PubMed1980

Consultees' representations of consultants' psychiatric diagnoses.

In an attempt to characterize consultees' representations of consultants' psychiatric dagnoses, the authors reviewd the medical records from 190 psychiatric consultations in a general hopsital. Using specific outcome criteria, they rated 50% of representations as concordant and 39% as nonconcordant. Five variable,s icluding the primary medical diagnosis at discharge and the referring service, were significantly related to concordance. Surprisinlgy, concordance was independent of the psychiatric diagnosis, indicating theat consultees did not respond differentially to varying magnitudes and implications of the different disorders. This work raises the question of possible strategies to improve receptivity to psychiatric diagnoses in the consultation setting.

Attitude of Health Personnel↗
PubMed1980

Two-dimensional echocardiography in mitral annulus calcification.

Mitral annular calcification, established by fluoroscopy, was studied by M-mode and two-dimensional echocardiography in 18 patients. M-mode echocardiography revealed the typical dense, linear echo of mitral annular calcification, but not its extent. Two-dimenstional echocardiography demonstrated a dense, elipsoidal echo at the junction of the left atrium and ventricle in the long axis view, and an area of calcification below the mitral valve in the short axis view. These patterns were not seen in 20 control patients without mitral annular calcification by fluoroscopy. Two-dimensional echocardiography establishes the site and extent of mitral annular calcification, minimizes the potential for diagnostic error associated with M-mode echocardiography, and is superior to M-mode echocardiography for the recognition of mitral annular calcification.

Aged↗
PubMed1980

Hepatic necrosis in rats following halothane administration: protective effect of diethyldithiocarbamate.

Foci of necrosis have been observed in the liver of 50% of enzyme-induced rats treated with halothane. The frequency of liver necrosis was significantly reduced by treatment with the free radical scavenger diethyldithiocarbamate. The severity of the lesion was not increased by repeated exposures to the anesthetic, and, although the frequency of liver necroses may be greater, the differences were not statistically significant.

Anesthesia, Inhalation↗
PubMed1980

Evaluation of kerb negotiation in a prototype and standard model wheelchair.

This article outlines an evaluatory study of kerb negotiation in a conventional wheelchair and a prototype diamond configuration, lever articulated wheelchair. The kerb negotiation sequence in both models is presented with the results of tests involving users able to negotiate kerbs (N = 16); users unable to negotiate kerbs (N = 15); and non-wheelchair users (N = 20). Results indicate preferences for the prototype amongst the first group, particularly for kerb descent. Free rolling tests of the loaded wheelchairs over various terrains revealed that while the standard wheelchair invariably turned downhill the prototype was relatively insensitive to loss of direction on sideslopes. A significant number of subjects (P = 0.01, N = 20) found the articulated framework of the prototype reduced the difficulties of self propulsion over rough and cambered surfaces. The prototype was found to possess a smaller turning circle (103 cm to 122 cm) and a longer wheelbase (94.7 cm to 39.7 cm) than the standard model though overall dimensions were broadly comparable. The implications of the prototype wheelbase for manual, attendant and powered propulsion are considered.

Ergonomics↗
PubMed1980

The uptake of horseradish peroxidase by neuronal elements within the guinea-pig distal colon and its subsequent retrograde transport to the inferior mesenteric ganglion: an in vitro study using an intact neuronal system.

An in vitro guinea-pig preparation comprising the inferior mesenteric ganglion (IMG), the colonic nerves, and a segment of the distal colon was used to study the uptake and retrograde transport of horseradish peroxidase by intact neurons. Peroxidase rapidly penetrated the colonic wall from the lumen and was taken into autonomic nerves by pinocytotic vesicles, usually of the coated variety. The peroxidase subsequently appeared in long vesicles within the axons, and, 24 hours later, could be detected in many neuronal perikarya throughout the IMG. The similarities between the modes of uptake of peroxidase by damaged and intact axons are discussed.

Animals↗
PubMed1980

The uptake of intravenous horseradish peroxidase by the guinea-pig inferior mesenteric ganglion.

The uptake of intravenously injected horseradish peroxidase (HRP) by the neuronal perikarya and SIF cells has been studied in the guinea-pig inferior mesenteric ganglion (IMG). The HRP rapidly penetrated the walls of the blood vessels within the ganglion and was taken up by neurons and SIF cells by means of coated pinocytotic vesicles. HRP reaction product was subsequently found within larger vesicles which were most prominent 6--9 hours after injection. Thirty hours after injection all the neurons and SIF cells within the IMG were free of peroxidase reaction product. The implications of these findings were considered in relation to retrograde axonal transport studies in autonomic neurons.

Animals↗
PubMed1980

Endoscopy--Review.

Explore the source record for details and available documents.

Bronchoscopy↗
PubMed1980

Cerebrospinal fluid edema and its sequelae in hydrocephalus.

CSF edema is observed in the periventricular white matter in acute hydrocephalus especially when the intraventricular pressure is elevated; there is usually no detectable disturbance of the blood-brain barrier. Histological and ventricular perfusion studies suggest that CSF flows through the intact or disrupted ependyma into the periventricular white matter when the normal pathways of drainage are occluded. Absorption of fluid into the blood probably occurs through the periventricular blood vessels as an alternative pathway of CSF drainage. There is tissue damage in the edematous periventricular white matter and gliosis ensues. However, the degree of active tissue disruption is reduced in the chronic stages of hydrocephalus when the CSF edema is often reduced.

Acute Disease↗
PubMed1979

The uptake of horseradish peroxidase by damaged autonomic nerves in vitro.

The uptake of horseradish peroxidase by damaged autonomic nerves was studied in vitro. Large amounts of the enzyme penetrated the axons in a diffuse (nonvesicular) form. This occurred within 90 minutes of application of the enzyme. Twenty four hours after application of the enzyme diffuse peroxidase was still present in the axoplasm, but it was 'diluted' as a result of great axonal swelling. Pinocytotic uptake of the enzyme was observed both 90 minutes and 24 hours after application of the enzyme. The swollen axons close to the point of ligation showed most evidence of pinocytotic uptake, largely into coated vesicles, and much membrane-bound peroxidase reaction product was present. The uptake of peroxidase in a membrane-bound form may be of particular significance for the subsequent retrograde transport of the enzyme.

Animals↗