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Biomedical subjects

M Morgan

Publications and source records attributed to M Morgan.

At least 199 records · Page 11Linked to original sources
PubMed1993

Genetic counselling in Noonan syndrome.

A clinical and echocardiographic study is presented of 117 families with Noonan syndrome. The 117 families contained 144 individuals with typical Noonan syndrome. The age range of these individuals was from one week to 45 years (mean 12.0 years). One parent was definitely affected with Noonan syndrome in only 14% of the 117 families (mother 11%, father 3%). In a further 31% of families, one parent had possible signs of Noonan syndrome, based on facial appearance only. Within the apparently sporadic group of probands there was no evidence of increased parental age. Echocardiography demonstrated no cases of subclinical cardiac disease in all first degree relatives examined, and clinical examination alone missed no case of cardiac disease. Segregation analysis of affected pedigrees confirmed autosomal dominant inheritance. If both parents had only possible or no signs of Noonan syndrome, subsequent to the birth of the first child with Noonan syndrome in a family, an empiric recurrence risk of 5% was obtained.

Adult↗
PubMed1993

Selection of Chinese hamster ovary cells (CHO-K1) with reduced glutamate and aspartate uptake.

Transport of L-[3H]glutamate into Chinese hamster ovary cells (CHO-K1) was characterized and the results used to design a tritium suicide selection for cells with transport defects. Replicas of surviving colonies on polyester cloth disks were screened by autofluorography for reduced uptake and two mutant clones, Ed-A1 and Ed-B8, were obtained. Uptake of glutamate through a sodium-dependent system in both mutants was characterized by significant reductions in Vmax and increases in Km compared to parental cells, but their response to removal of extracellular sodium differed, suggesting distinct mutations in the two lines. The Vmax of aspartate uptake through this system was reduced in both mutants, to one-ninth in the case of Ed-B8. Glutamate uptake through a sodium-independent system was not altered in either mutant. Surprisingly, acid-soluble intracellular pools of several amino acids were higher in both mutants.

Animals↗
PubMed1993

Tracking of "moving" fused auditory images by children.

Recent investigations (Cranford, Boose, & Moore, 1990a,b; Moore, Cranford, & Rahn, 1990) studied the ability of normal adult subjects to localize sounds under conditions that elicit the Precedence Effect. In different tests, subjects were required either to report the perceived location of a stationary fused auditory image (FAI) or track the apparent motion of a "moving" FAI. Movement of the FAI was simulated by incrementally varying the delay between pairs of clicks presented, one each, from two matched loudspeakers placed on opposite sides of the listener. In the present study, groups of normally developing children, ranging in age from 6 to 12 years of age, were tested with these two procedures. Although subjects performed at normal adult levels with the stationary FAI test, a significant age-related trend was observed with the moving FAI test. The younger children exhibited poorer tracking performances than did the older children. These results provide evidence that significant changes in binaural temporal processing abilities may occur in the early childhood years.

Acoustic Stimulation↗
PubMed1993

Why do mothers consult when their children cough?

Mothers' beliefs and evaluations of their child's illness were studied in a group of 30 mothers who had consulted a general practitioner because of a cough. Data were collected by tape-recorded semi-structured interviews conducted in their own homes. A major concern for mothers was their fear that their child was going to die, usually because of choking on phlegm or vomit, but also through an asthma attack or cot death. Mothers were also worried that their child would develop long-term chest damage. Particularly important in mothers' assessments were their experience of disturbed sleep because of worries about their child dying at night and their belief that the cough was 'on the chest' which gave rise to worries about dying through choking on phlegm and long-term chest damage. Antibiotics were commonly believed to be required to break up phlegm which might cause the long-term damage or the choking and death.

Attitude to Death↗
PubMed1993

The Drosophila clathrin heavy chain gene: clathrin function is essential in a multicellular organism.

The clathrin heavy chain (HC) is the major structural polypeptide of the cytoplasmic surface lattice of clathrin-coated pits and vesicles. As a genetic approach to understanding the role of clathrin in cellular morphogenesis and developmental signal transduction, a clathrin heavy chain (Chc) gene of Drosophila melanogaster has been identified by a combination of molecular and classical genetic approaches. Using degenerate primers based on mammalian and yeast clathrin HC sequences, a small fragment of the HC gene was amplified from genomic Drosophila DNA by the polymerase chain reaction. Genomic and cDNA clones from phage libraries were isolated and analyzed using this fragment as a probe. The amino acid sequence of the Drosophila clathrin HC deduced from cDNA sequences is 80%, 57% and 49% identical, respectively, with the mammalian, Dictyostelium and yeast HCs. Hybridization in situ to larval polytene chromosomes revealed a single Chc locus at position 13F2 on the X chromosome. A 13-kb genomic Drosophila fragment including the Chc transcription unit was reintroduced into the Drosophila genome via P element-mediated germline transformation. This DNA complemented a group of EMS-induced lethal mutations mapping to the same region of the X chromosome, thus identifying the Chc complementation group. Mutant individuals homozygous or hemizygous for the Chc1, Chc2 or Chc3 alleles developed to a late stage of embryogenesis, but failed to hatch to the first larval stage. A fourth allele, Chc4, exhibited polyphasic lethality, with a significant number of homozygous and hemizygous offspring surviving to adulthood. Germline clonal analysis of Chc mutant alleles indicated that the three tight lethal alleles were autonomous cell-lethal mutations in the female germline. In contrast, Chc4 germline clones were viable at a rate comparable to wild type, giving rise to viable adult progeny. However, hemizygous Chc4 males were invariably sterile. The sterility was efficiently rescued by an autosomal copy of the wild-type Chc gene reintroduced on a P element. These findings suggest a specialized role for clathrin in spermatogenesis.

Amino Acid Sequence↗
PubMed1993

The genius infrared tympanic thermometer. An evaluation for clinical use.

A clinical tympanic thermometer was evaluated. In vitro it was found to be accurate over the temperature range 28 degrees C to 40 degrees C. Clinical assessment was made during the cooling and rewarming phases of patients undergoing surgery with the aid of cardiopulmonary bypass and compared with the results obtained with an Ellab thermocouple thermometer. It was also used in patients in the intensive care unit in whom core temperature was being measured using the thermistor incorporated in a pulmonary artery catheter. The infrared thermometer was found to be accurate, rapidly responding and easy to use.

Body Temperature↗
PubMed1993

Eltanolone for induction of anaesthesia and to supplement nitrous oxide for minor gynaecological surgery.

We have used eltanolone to induce anaesthesia and by intermittent injection to supplement nitrous oxide during maintenance in 50 patients undergoing minor gynaecological surgery; opioids were not used. Induction of anaesthesia was remarkably trouble free and achieved with a single dose of 0.5 mg.kg-1 in 90% of patients. Pain on injection was not a feature. Satisfactory anaesthesia was achieved in 84% of patients; eight required addition of isoflurane. There were minimal cardiovascular changes and apnoea on induction occurred in only one patient. Recovery times were acceptable.

Abortion, Therapeutic↗
PubMed1993

Clinical analysis of 125 patients with the lupus anticoagulant.

A retrospective analysis of 125 consecutive lupus anticoagulant (LA) positive patients and 125 age, sex matched lupus anticoagulant negative controls is reported with the aims of defining further the clinical spectrum of disease, determining at-risk subgroups and management strategies. There was no significant difference in the incidence or pattern of complications in those with systemic lupus erythematosus (SLE) and related disorders, and those without SLE. Venous thromboembolism, immune thrombocytopenia, foetal loss, depression and hypertension were statistically more common in the LA group than in the control group. In contrast to previous reports, children aged ten years or less with the LA developed significantly more complications than controls. Patients with the LA secondary to drugs also developed complications, a finding which is also at variance with previous reports. There was a significant difference in the outcome of arterial disease (p < 0.04) and venous thromboembolism (p < 0.001) when long term anticoagulation was part of the treatment regimen.

Adolescent↗
PubMed1993

Television and School Performance.

Although the question of whether television harms, helps, or has no effect on school performance has engaged researchers for many years, the answer remains elusive. Before-after studies and survey studies are controversial in terms of both interpretation and methodology. The author argues for integration of television into the curriculum to take advantage of its unique potential for democratization.

Journal Article↗
PubMed1993

EEG monitoring during angiographic balloon test carotid occlusion: experience in sixteen cases.

Ipsilateral hemispheric ischaemia related to permanent or temporary arterial occlusion at the time of operation is a potential risk of surgery upon some aneurysms or tumours which involve the internal carotid artery. Presurgical evaluation of the risks of temporary or permanent internal carotid artery occlusion may help predict patients in these circumstances at risk of stroke. Balloon test occlusion studies involve the elective preoperative occlusion of the internal carotid artery by a deflatable balloon inserted into the cerebral circulation under angiographic control. We have performed 16 balloon test occlusion studies; 2 subjects developed clinical and electroencephalographic changes when the carotid artery was temporarily occluded, and these changes reverted to normal when the balloon was deflated. The results of the test occlusion studies helped in planning the surgical management of all the subjects involved.

Adolescent↗
PubMed1993

Clostridium septicum gangrene complicating a closed femoral fracture.

One of the basic principles of orthopedic surgery is that gas gangrene does not develop in closed fractures. That there are exceptions to this rule is demonstrated by the following report of an extremely rare case. Clostridium septicum myonecrosis developed after surgical treatment of a closed femoral fracture in a fit 45-year-old man, treated by antibiotics. The patient survived after having a right hip disarticulation and administration of high doses of intravenous penicillin. Prophylactically administered cephalosporins failed to prevent the Clostridial infection.

Clostridium↗
PubMed1993

Relative risk of aortic and femoral insertion of intraaortic balloon pump after coronary artery bypass grafting procedures.

We compared the preoperative, operative, and postoperative characteristics of patients who required balloon pumps after coronary artery bypass graft procedures to determine the relative risks of femoral and aortic insertion. The balloon pump was inserted into the ascending aorta when femoral insertion was not possible because of occlusive disease or small femoral arteries. Femoral insertion was performed in 81 patients and aortic insertion in 42 patients. Patients with aortic insertion were more likely to be small and female (p < 0.05) and were more likely to have carotid bruits and a history of strokes or transient ischemic attacks (p < 0.05). Death was more common in the patients with aortic insertion (18/42, 42.9%) than in those with femoral insertion (19/81, 23.4%) (p < 0.05), as calculated with single regression analysis. Route of insertion was not a predictor of operative death, according to multiple regression analysis. Leg complications were more common in patients with femoral artery insertion (23/81, 28.4%) than in those with aortic insertion (0/42, 0.0%) (p < 0.05). No sternal complications occurred in either group. New neurologic abnormalities were not significantly different between the patients with aortic and femoral insertion. Aortic insertion is a safe alternative to femoral insertion of intraaortic balloon pumps and is associated with fewer leg complications in small or diseased iliac and femoral arteries. The greater mortality rate with aortic insertion is related to greater comorbidity rate in these patients.

Aged↗
PubMed1992

Constraints on innovatory practice: the case of day surgery in the NHS.

Rates of adoption of new technology or innovatory practices depend upon their inherent managerial and clinical incentives. Rates will be highest where these incentives coincide and lowest where both are weak. Within this framework we examine the current low rate of adoption of day surgery in the National Health Service (NHS) of the United Kingdom (UK). We assess the current managerial incentives for the introduction of day surgery in terms of its potential either to achieve financial savings or to allow expansions in overall hospital caseload. These are both shown to have been low within the context of the traditional method of funding health care in the NHS. Clinical attitudes and their perceptions of the barriers to day surgery are examined based on data from a survey of 240 consultant surgeons. A high proportion of surgeons regard day surgery as clinically acceptable for a wide range of procedures, but the limited clinical appeal of day surgery procedures and the lack of day facilities have further limited its adoption. These findings are considered in the context of the revised methods of funding hospital services in NHS, introduced from April 1991. Priorities may change with managerial incentives playing a greater role in the introduction of new technologies and innovatory practices.

Ambulatory Surgical Procedures↗
PubMed1992

Exchange of gene activity in transgenic plants catalyzed by the Cre-lox site-specific recombination system.

The Cre-lox site-specific recombination system of bacteriophage P1 was used to excise a firefly luciferase (luc) gene which had previously been incorporated into the tobacco genome. The excision event was due to site-specific DNA recombination between two lox sequences flanking the luc gene and was catalyzed by the Cre recombinase introduced by cross-fertilization. Recombination resulted in the fusion of a promoter with a distally located hygromycin phosphotransferase (hpt) coding sequence and the excision event was monitored as a phenotypic change from expression of luc to expression of hpt. The efficiency of recombination was estimated from the exchange of gene activity and confirmed by molecular analysis. The relevance to potential applications of site-specific deletion-fusion events for chromosome engineering are discussed.

Agrobacterium tumefaciens↗