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Biomedical subjects

A Mitchell

Publications and source records attributed to A Mitchell.

At least 235 records · Page 13Linked to original sources
PubMed1989

Combined septal perforation and cardiac rupture after myocardial infarction. Clinical features and surgical considerations of a correctable condition.

The combination of septal perforation and cardiac rupture after myocardial infarction has rarely been reported. This article describes two cases of successful surgical repair of this condition and reviews another three cases previously reported in the literature. The important clinical features were as follows: (1) acute occlusion of a single dominant coronary artery; (2) renewed chest pain before perforation or rupture; (3) electromechanical dissociation at the time of frank rupture; (4) rupture through the left ventricular free wall; (5) in three patients both complications occurred within 3 days of the infarction, and in the other two patients they developed within three weeks. The main surgical considerations are as follows: (1) femoral cannulation to prevent exsanguination before instituting cardiopulmonary bypass; (2) electrically induced fibrillation to avoid systemic embolism; (3) a left ventricular approach to repair the septal perforation followed by infarctectomy; (4) concomitant revascularization was unnecessary. In conclusion, combined septal perforation and cardiac rupture after myocardial infarction is a potentially correctable condition that requires early diagnosis and prompt surgical intervention.

Acute Disease↗
PubMed1988

Studies of an S9-based metabolic activation system used in the mouse lymphoma L5178Y cell mutation assay.

The purpose of this work was to define, in this laboratory, the conditions of most general utility for the metabolic activation of chemicals to mutagens in the mouse lymphoma L5178Y cell tk+tk- ----tk-tk- assay. The approach used was to optimize the generation of non-toxic concentrations of NADPH from NADP glucose-6-phosphate (G6P) and G6P dehydrogenase, then use that system to examine the effects of increasing concentrations of Aroclor-1254-induced Fischer 344 male rat liver post-mitochondrial supernatant fluid (S9) upon the mutagenicity of chemicals. The promutagens were 2-acetylaminofluorene, cyclophosphamide, dimethylnitrosamine, methanol, 3-methylcholanthrene and procarbazine. It was determined that: (i) cell population growth was reduced at NADPH concentrations of greater than or equal to 1 mM; (ii) to ensure a maximum conversion of NADP to NADPH the G6P/NADP ratio should be two or greater; (iii) excess G6P (2.5 mM) is not harmful to the cells; (iv) toxicity due to S9 was observed at 12.5 mg whole liver equivalents (WLE)/ml (i.e. 50 microliters of a 25% liver S9 preparation per ml); (v) concentrations of S9 between 2.5 and 7.5 mg WLE/ml appeared to be adequate for the activation of the six promutagens to demonstrably mutagenic products.

Animals↗
PubMed1988

Quality of life in patients with inflammatory bowel disease.

To investigate the effect of inflammatory bowel disease (IBD) on the quality of life, we interviewed 43 patients with ulcerative colitis (UC) and 54 with Crohn's disease. Patients identified frequent and important problems in five areas. Primary bowel symptoms, systemic symptoms, and altered emotional function were common; functional and social impairment were less frequent. Systemic symptoms such as fatigue were more prevalent in patients with Crohn's disease. Apart from primary bowel complaints, patients seldom volunteered other facets of quality of life impairment; this was particularly true for impairment of emotional function. We conclude that despite troublesome intestinal and systemic symptoms, most patients with IBD avoid major disruption in work and personal lives. Physicians must inquire specifically about emotional problems relating to IBD; in particular, fear of surgery is important to address. Psychosocial interventions should be targeted to those patients with problems in this area.

Adult↗
PubMed1988

Gene for selenium-dependent glutathione peroxidase maps to human chromosomes 3, 21 and X.

A human glutathione peroxidase cDNA has been used as a probe to hybridize to DNAs isolated from human - rodent somatic cell hybrids that have segregated human chromosomes. A 609 bp probe which contains the entire coding region hybridizes to human chromosomes 3, 21 and Xp. Fragments of the cDNA coding sequence and of the 3' untranslated region were also used as probes. These fragments hybridized to each of the three chromosomes with the same efficiency, suggesting similarity between the loci, whereas an intronic probe detected only the gene on chromosome 3. The general organization of each gene was determined from the hybridization data. The data suggest that the locus on chromosome 3 is a functional gene containing a single intron and a pattern of restriction sites identical to those found in the cDNA coding sequence. The data also suggest that the sequences on chromosomes X and 21 have equal conservation of the 3' untranslated and coding sequences but do not contain introns, providing evidence that the latter two sequences are processed pseudogenes. A simple two allele polymorphism in PvuII digests was detected at the locus on chromosome 21.

Animals↗
PubMed1987

Patterns of calling time and ipecac availability among poison center callers.

Over a one-month period all telephone calls from the public (n = 3828) to a regional poison center were analyzed. The proportion of early calls (within ten minutes of exposure) decreased with age. Late calls (greater than 30 minutes) were significantly associated with higher hospital referral rates when compared with earlier calls in children younger than 5 years (4.6% vs 1.8%) and adults (33% vs 15%). Ipecac was available in 59% of the homes of callers with children younger than 5 years. Hospital referrals were significantly less common among children who had ipecac at home (1%) compared with children who did not (3%). While the availability of ipecac was similar among callers and a matched sample of households who previously called the poison center (58%), ipecac was much less frequently available (24%) among households whose members had not previously called the center. These data infer that educating the public to call the poison center promptly may result in reduction of hospital referrals. Poison education efforts should be targeted to populations with low ipecac availability and low utilization of the poison center.

Adolescent↗
PubMed1987

Preliminary results of the Nottingham breast self-examination education programme.

Between June 1979 and December 1984, 49,573 women (study population) between the ages of 45 and 64 years and living in one health district were invited to attend breast self-examination sessions as part of the DHSS 'UK Trial of Early Detection of Breast Cancer'. Of the women invited 50.2 per cent attended for education. A total of 319 breast cancers were diagnosed in the study population during this period. The tumour characteristics, patient prognostic groups and survival have been compared with a control population consisting of the 319 consecutive breast cancers diagnosed immediately before the start of the DHSS trial, in women of the same age group and living in the same health district. There has been a significant reduction in the size at presentation of operable tumours (P less than 0.01) and there has been a small (3.4 per cent) reduction in lymph node involvement, but this is not significant. The rates of presentation of both in situ and advanced carcinoma have not significantly changed following the introduction of a breast self-examination education programme. At this stage no overall survival difference has been identified between the two groups but the median follow up of the study population is limited (25 months).

Breast↗
PubMed1987

Sarcoidosis: a pattern of clinical and morphological presentation.

The diagnosis of cardiac sarcoidosis, particularly when there is no overt systemic involvement, is frequently delayed because of its varied manifestations. Focal left ventricular wall motion abnormalities were recognised in five patients with sarcoidosis. Three patients showed abnormal regional wall motion in the basal portion of the ventricular septum and free wall with sparing of the apex. The angiographic appearances supported the echocardiographic findings which were atypical of ischaemic heart disease. The remaining two patients both had diffuse left ventricular hypokinesia, with a focal abnormality that was most pronounced in the anteroapical region; this pattern is often seen with coronary disease. The recognition by echocardiography or angiography of focal abnormalities of wall motion affecting the basal portion of the ventricular septum should suggest the possibility of myocardial sarcoidosis even in the absence of recognised systemic manifestations.

Adult↗
PubMed1987

Increased sensitivity of the denervated transplanted human heart to isoprenaline both before and after beta-adrenergic blockade.

It is not known whether surgical denervation leads to increased beta-receptor sensitivity after human cardiac transplantation. We assessed cardiac beta-receptor sensitivity by studying the heart rate response to isoprenaline of the denervated donor heart as compared with the innervated recipient heart in eight patients who underwent heterotopic cardiac transplantation and in six patients with orthotopic transplantation. Changes in the donor and recipient hearts seen in these 14 patients were further compared with those seen in 10 normal volunteers. Incremental intravenous infusion of isoprenaline (5, 10, and 15 ng/kg/min) raised heart rate to a greater extent in the donor compared with the recipient hearts in the eight patients who had heterotopic grafts (slopes [beats/min/ng/kg]: donor = +2.26, recipient = +1.59; p less than .01). In addition, the donor hearts of the transplant patients were more sensitive than hearts of the normal volunteers (slopes: donor = +2.26, normal = +0.94; p less than .01). The changes in the two groups of donor hearts were similar (slopes: orthotopic = +2.24, heterotopic = +2.27; NS). The recipient hearts in the patients with heterotopic transplants were more sensitive than the hearts of the normal volunteers (p less than .05), suggesting that the observed differences in isoprenaline sensitivity in the patients with heterotopic grafts were not caused by a decreased sensitivity of the recipient heart. After beta-blockade, the heart rate responses to isoprenaline were attenuated to the same extent in denervated and innervated hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1986

Molecular and physical arrangements of human DNA in HRAS1-selected, chromosome-mediated transfectants.

We used mitotic chromosomes isolated from a human EJ bladder carcinoma cell line for morphological transformation of mouse C127 cells. These chromosome-mediated transformants were analyzed for cotransfer of markers syntenic with c-Ha-ras-1 on human chromosome 11. We also used cloned, dispersed human DNA repeats, in a general mapping strategy, to quantitate the amounts and molecular state of human DNA transferred along with the activated c-Ha-ras-1 gene. In situ hybridization was used to visualize the physical state of the transfected human chromatin. The combined use of these various techniques revealed the occurrence of both chromosomal and DNA rearrangements. However, our analysis also demonstrated that, in general, very substantial lengths of DNA are transferred intact. Closely linked markers are likely to cosegregate. Therefore, these transformants should be invaluable sources for the complete molecular cloning of isolated fragments of the short arm of human chromosome 11.

Cell Line↗
PubMed1986

Late pericardial tamponade and coronary arteriovenous fistula after trauma.

A 48 year old man presented with cardiac tamponade six weeks after an apparently minor penetrating chest injury. Thoracotomy showed a haemopericardium with no actively bleeding vessel. Re-investigation eleven months later, prompted by persistent chest pain, showed the presence of a fistula between the second diagonal of the left anterior descending coronary artery and a cardiac vein.

Arteriovenous Fistula↗
PubMed1986

Comparison of the relative importance of tyrosine-specific vinculin phosphorylation and the loss of surface-associated fibronectin in the morphology of cells transformed by Rous sarcoma virus.

We have investigated the relative importance of tyrosine-specific phosphorylation of vinculin and the loss of surface-associated fibronectin in the maintenance of the rounded morphology characteristic of chick embryo fibroblasts (CEF) transformed by Rous sarcoma virus (RSV). To address this question we have examined the interaction of CEF and RSV-CEF in vitro with exogenously added fibronectin in both 3-day culture experiments and short-term, 3-h spreading experiments. We report that the addition of human plasma fibronectin to cultures of RSV-CEF results in the restoration of a near-normal morphology, as has been described previously, with the added fibronectin incorporated into an extracellular matrix. However, the phosphotyrosine content of vinculin in these cells was unchanged from that of control, untreated RSV-CEF despite the change in morphology. In short-term spreading experiments RSV-CEF were unable to adopt a fully spread morphology on fibronectin substrates, with defects in the formation of adhesion plaques and microfilament bundles compared with untransformed CEF. pp60v-src was present in the newly formed adhesion plaques of RSV-CEF spreading on fibronectin substrates. The relevance of these results to the maintenance of the transformed phenotype is discussed.

Animals↗
PubMed1985

Vasopressin effects on the small intestine: a possible factor in paralytic ileus?

Experiments were performed on luminally perfused, isolated, canine, jejunal segments in vivo to determine the effects of vasopressin on intestinal motility, myoelectrical activity and absorption. Intravenous vasopressin abolished spike activity and sometimes disrupted slow wave activity. The jejunum became atonic with intraluminal pooling of perfusate. Transit time was prolonged and intestinal absorption of water was decreased. Radionuclide imaging of the intestinal contents showed a doubling of intraluminal volume with vasopressin and confirmed the loss of intestinal motility. It is suggested that the high plasma levels of vasopressin which are known to follow laparotomy may be a factor in the development of postoperative ileus.

Action Potentials↗
PubMed1985

The borderline diagnosis and integration of self.

To try to encompass what is meant by borderline with parameters that are too delineating can lead to conceptual difficulties and confusion for several reasons: The human psyche is too complex and probably has too much of the quality of a gestalt to be understood adequately by dichotomizing thinking; an individual does not experience himself as operating in discrete units, but as a unified whole; and the most characteristic manifest quality of the borderline picture is its tendency toward a chaotic functioning that somehow always spills over any defining boundaries which are set up to attain conceptual containment. If we then accept our limitations on the precision and order with which we can comprehend it, the understanding of borderline might be supplemented by seeing it in terms of the subjective experience of an integrated self. This offers a more holistic approach that tends not to be so subject to objectifying compartmentalization. It is more in tune with the subjective experiencing a person has of that which defines and moves him in the world. And it offers a referent axis along which the distance one has traveled in the borderline direction might be gleaned. Finally, the relationship of the borderline diagnosis to character disorder might be looked this way: The diagnosis does not refer to a particular character disorder or to a group of disorders. It emerges in all character pathology to the degree that the experiencing of an integrated and whole sense of self, which is at the heart of character structure, is diminished.

Borderline Personality Disorder↗