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Biomedical subjects

D M Chapman

Publications and source records attributed to D M Chapman.

28 records · Page 2Linked to original sources
PubMed1987

Anatomical studies to support the expanded use of the internal mammary artery graft for myocardial revascularization.

The internal mammary artery pedicle graft is frequently used for coronary bypass. Five internal mammary artery pedicle grafts, harvested but not utilized for coronary bypass, underwent histological examination. The histological studies demonstrated that the vasa vasorum were confined to the adventitia and did not penetrate the media of the internal mammary artery. These observations indicate that the media is nourished entirely from the lumen and suggest that harvesting the internal mammary artery as a free graft would not subject the wall of the artery to ischemic injury. Subsequent to these studies, we used the right internal mammary artery as a free graft to revascularize the distal circumflex coronary artery in 12 patients. The free graft was anastomosed to marginal branches of the circumflex and was then brought up to the left internal mammary artery pedicle graft and anastomosed end-to-side. This procedure has not resulted in excessive postoperative bleeding or sternal infections, and has relieved the anginal syndrome in all 12 patients.

Aged↗
PubMed1982

Localization of methylene blue paramolybdate in vitally stained nerves.

Methylene blue taken up by living neurons can be preserved for electron microscopy in a fixative containing osmium tetroxide and ammonium paramolybdate at pH 5.2. Paramolybdate is the buffer, precipitating agent and main osmotic ingredient; it does not function as an electron stain unless methylene blue is present. The low pH keeps the dye/paramolybdate complex from dissolving. Neither the low pH nor drastic dehydration from water to absolute ethanol harm the tissue. The staining mechanism involves cationic methylene blue associating with anionic structures such as microtubules and neurofilaments in the living cell; during fixation paramolybdate forms a precipitate with the dye at the staining sites. This fixative does not preserve microtubules unless they are first vitally stained.

Animals↗
PubMed1978

The role of IgA in the prevention of bacterial colonization of the jejunum in the vagotomized subject.

The efficacy of three mechanisms of defence against jejunal bacterial colonization (i.e. gastric acid, vagal and pyloric integrity and intestinal IgA) has been investigated. Only in subjects with disturbance of all three mechanisms did significant jejunal colonization occur, and this was invariably associated with severe diarrhoea. Clearly normal intestinal IgA is of critical importance in the prevention of jejunal bacterial colonization in the vagotomized subject.

Diarrhea↗
PubMed1976

Association of HLA-A9 and HLA-B5 with Buerger's disease.

Eighteen patients who satisfied stringent criteria for the diagnosis of Buerger's disease, healthy controls, and patients with atherosclerosis were tested for various HLA antigens. The incidence of HLA-A9 and HLA-B5 was significantly greater among those with Buerger's disease. This finding supports the concept that Buerger's disease is a distinct clinicopathological condition.

Adult↗
PubMed1976

IgA deficiency and severe post-vagotomy diarrhoea.

Between January, 1969, and December, 1973, 2058 truncal vagotomies were performed in the Merseyside Regional Health Authority area. 14 of these patients subsequently developed severe post-vagotomy diarrhoea and were extensively investigated. 6 were found to have IgA deficiency. It is suggested that antecedent IgA deficiency may account for the varied reported incidence of severe post-vagotomy diarrhoea and that preoperative screening could reduce the incidence of this complication.

Adult↗
PubMed1975

Dichromatism of bromphenol blue, with an improvement in the mercuric bromphenol blue technic for protein.

Staining of protein in sections using the mercuric bromphenol blue technic is improved by staining with 1% HgCl2 and 0.05% bromphenol blue in 2% aqueous acetic acid for 15 min at room temperature. Rinse slides 20 min in 2 changes of 0.5% aqueous acetic acid. Blot and give 2 fast changes in absolute ethanol with agitation before transferring to xylene. Transfer slide to 0.5% n-butylamine in xylene for a few seconds until the section is blue, then, after 2 changes of xylene, mount in DPX. Spectrophotometric analysis of this blue dye at different concentrations and with or without heparin showed that the reddish hues are due to dichromatism and not metachromasia.

Animals↗
PubMedDate not supplied

Emergency thoracotomy: comparison of medical student, resident, and faculty performances on written, computer, and animal-model assessments.

OBJECTIVE: In clinical practice, thoracotomy and other critical emergency procedures are rarely required. Consequently, medical students and residents have difficulty acquiring procedural competency in these critical procedures. The authors developed objective written, computer, and animal-model assessments of thoracotomy procedural competency to permit comparison of the reliability and validity of these three procedural assessment modalities. METHODS: Thoracotomy procedural competency was evaluated for 18 persons at three levels of training (medical student, resident, faculty), using written, computer, and animal-model assessments. A prospective, sequential assessment design was used, with the examinees serving as their own controls. Procedural competency was defined in terms of performance time (animal time scale) and performance accuracy (written accuracy, computer accuracy, and animal accuracy scales) for three thoracotomy procedures (opening the chest, pericardiotomy, and aortic cross-clamping). Level of training was the independent variable, and procedural competency scores were the outcome measures. Confounding variables included previous thoracotomy and computer experience. RESULTS: Computer and animal-model assessments produced reliable results (Chronbach's alpha > 0.50). The animal time scale and computer accuracy scale best reflected the expected skill differences among levels of physician training, providing support for construct validity. In contrast, written and animal accuracy scale scores did not significantly differ by level of physician training. Moreover, previous thoracotomy experience (i.e., number of procedures previously performed) was not a significant predictor of procedural competency. CONCLUSIONS: This study demonstrates that critical emergency medicine procedures can be evaluated reliably and validly using computer simulation and animal-model assessments. Neither previous thoracotomy experience nor knowledge of procedure content adequately predicts thoracotomy competency.

Animals↗
PubMedDate not supplied

Gastroesophageal reflux disease in children older than two years of age.

Since there are few studies examining gastroesophageal reflux (GER) in healthy children beyond infancy, we report our experiences treating children older than two with this condition. GER was diagnosed by either an abnormal extended intraesophageal pH monitoring (pH study) or presence of histological esophagitis. Thirty-seven patients met the criteria, ages 3 to 19 years (mean 11) and 68% were males. Common symptoms were vomiting, abdominal or chest pain, heartburn and regurgitation. Mean duration of symptoms was 28.7 months, and six patients had severe esophagitis, and one had Barrett's esophagus. Patients with severe esophagitis were older and had strongly positive pH study parameters compared to the rest of patients (p < 0.05). All patients were treated with prokinetic and acid reducing agents for 8 to 12 weeks. Sixty-two percent responded to initial course and remained asymptomatic during the follow-up period. Nissen fundoplication was recommended to five patients (13.5% of study population) because of refractory GER. Four of these patients who required surgery had severe esophagitis. In summary, GER in normal older children is a chronic disease with potentially severe complications. All patients should be evaluated by pH study and endoscopic esophageal biopsies, and have careful follow up.

Adolescent↗