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Biomedical subjects

C Dunn

Publications and source records attributed to C Dunn.

At least 19 recordsLinked to original sources

Linkage of a cardiac arrhythmia, the long QT syndrome, and the Harvey ras-1 gene.

Genetic factors contribute to heart disease. In this study, linkage analyses have been performed in a family that is predisposed to sudden death from cardiac arrhythmias, the long QT syndrome (LQT). A DNA marker at the Harvey ras-1 locus (H-ras-1) was linked to LQT with a logarithm of the likelihood ratio for linkage (lod score) of 16.44 at theta = 0, which confirms the genetic basis of this trait and localizes this gene to the short arm of chromosome 11. As no recombination was observed between LQT and H-ras-1, and there is a physiological rationale for its involvement in this disease, ras becomes a candidate for the disease locus.

Chromosome Mapping

Consistent linkage of the long-QT syndrome to the Harvey ras-1 locus on chromosome 11.

The long-QT syndrome (LQT; Ward-Romano syndrome) is a cardiac disorder that is inherited as an autosomal dominant trait. Affected family members suffer from recurrent syncope and sudden death due to ventricular arrhythmias. Recently, we identified a DNA marker on the short arm of chromosome 11 (the Harvey ras-1 locus [H-ras-1]) that was completely linked to the LQT locus in one large family. In the study presented here, we performed linkage investigations on six new and unrelated families with LQT. The LQT locus was again completely linked to the H-ras-1 locus in all families examined, with a combined lod score of 5.25 at a recombination fraction of 0. This work confirms our previous assignment of the LQT locus to chromosome 11p and supports the hypothesis that LQT is genetically homogeneous. As no obligate recombinants were identified in either this or our previous study, the H-ras-1 protooncogene remains a candidate for the LQT disease gene. Identification of LQT families with locus homogeneity is an important step in the development of a refined genetic map of this locus and will help determine whether the H-ras-1 marker would be of general use for presymptomatic diagnosis of this potentially fatal, but treatable, disorder.

Chromosome Mapping

Talking quality.

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Humans

Speech analyses of four children with repaired cleft palates.

Four males with surgically repaired cleft palates, between 3 years 2 months and 3 years 11 months of age, served as subjects. Speech samples were collected and subjected to a number of analyses, including phonetic inventories and analysis of phonological processes. Frequency counts of error types, including gross or compensatory substitutions, were also tallied. The results revealed that the subjects were similar to one another with respect to their phonetic inventories. They differed considerably, however, in the frequency and types of phonological processes used. Those differences may be attributed to variations in language skills. The data strongly suggest that not all of the articulatory problems among the children can be explained solely on the basis of present or past structural deficits.

Child, Preschool

Coma blisters: report and review.

Coma blisters are self-limited lesions that occur in the setting of coma of various causes, but are most commonly associated with barbiturate overdose. Examination of a skin biopsy specimen demonstrates the characteristic presence of eccrine sweat duct necrosis. Although the exact cause of coma blisters remains unknown, they are not related to underlying infections or rheumatologic disorders, and do not contraindicate the continued therapeutic use of barbiturates.

Adult

Do lung volumes change with sleep state in the neonate?

We have studied 12 healthy full-term babies, mean age 3.2 days, using physiological criteria--EEG, electrooculogram, electromyogram, respiratory regularity and visible movement--to assess sleep state, and a respiratory jacket to record changes in functional residual capacity (FRC). A total of 593 min of sleep data were analysed. Of the recordings, 39% were scored as quiet sleep, 40% as active and 21% as indeterminate sleep. The mean maximum variation in FRC overall was 29 ml (SD +/- 15.4 ml). Examination of these figures showed that FRC variations during sleep state changes were smaller than those seen within a defined sleep state. We conclude that changes in sleep state are not associated with variations in FRC.

Functional Residual Capacity

Invasive monitoring and anaesthetic management of a parturient with mitral stenosis.

The anaesthetic management of a parturient with mitral stenosis is presented and discussed. In particular, the beneficial effects of epidural anaesthesia for vaginal delivery are described with respect to the significant improvement noted in haemodynamic parameters. The information derived from the pulmonary artery catheter greatly assisted the management of the patient throughout labour and in the puerperium.

Adult

Serological survey for human monkeypox infections in a selected population in Zaire.

About 3460 persons living in Kole zone of East Kasai, in Zaire, were examined and their sera screened initially by a haemagglutination-inhibition test. Of these, 667 (19%) were positive. Radioimmunoassay adsorption tests for the presence of monkeypox- or vaccinia-specific antibodies gave unequivocal results in 300 of these sera; the remaining 47 were nonspecific. Monkeypox-specific antibodies were found in sera of 27 individuals, of all ages and both sexes, giving an overall prevalence rate of monkeypox virus-specific antibodies of 0.8%. The prevalence rate was four times higher in the 5 to 9 year age group (1.3%) than in children aged 0 to 4 years (0.3%), and was highest (2.4%) in the 15 to 19 year age group. There was no significant difference in the prevalence rates between the sexes. As might be expected, there are substantially higher prevalence rates in persons living in forest galleries than in those in savannah, and among those living in areas where human monkeypox cases had occurred in the past compared with those living in other localities. Nineteen children whose sera showed specific monkeypox antibodies were re-examined. Twelve showed facial and body skin changes suggesting the presence of vesiculo-pustular disease in the past; four of these had been known registered monkeypox cases. Seven children had neither signs nor history of past vesiculo-pustular disease, suggesting that they had suffered from subclinical infection with monkeypox virus.

Antibodies, Viral

Effect of left atrial to left femoral artery bypass and renin-angiotensin system blockade on renal blood flow and function during and after thoracic aortic occlusion.

Temporary thoracic aortic occlusion can result in renal insufficiency with or without adjuncts to avoid distal hypoperfusion. In a canine model of thoracic aortic occlusion, left atrial to left femoral bypass was compared with blockade of the renin-angiotensin system. Renin-angiotensin system blockade with the converting enzyme inhibitor, MK422, resulted in restoration of baseline renal blood flow and glomerular filtration 30 minutes after cross-clamp release. Left atrial to left femoral bypass resulted in significant reduction in both renal blood flow and glomerular filtration 30 minutes after cross-clamp release. Stimulation of the renin-angiotensin system plays a significant role in the altered renal hemodynamics and glomerular filtration rates after thoracic aortic occlusion.

Angiotensin-Converting Enzyme Inhibitors

Four generations of probable person-to-person transmission of human monkeypox.

This paper examines an outbreak of five cases of human monkeypox which occurred in children belonging to two families living in the West Kasai region of Zaire during May-July 1983. Epidemiologic investigations suggest that the first case was infected from an animal source, possibly a monkey, and that each of the other four cases was infected from a previous human case. Three of these cases of presumed person-to-person transmission occurred in close household contacts. The other case infection occurred either by casual contact within the hospital compound, or possibly because of infection due to use of the same syringe for injections. Human monkeypox is the most important orthopoxvirus infection in the post-smallpox eradication period. The disease is a zoonosis and person-to-person transmission is rather difficult. Thus, this episode is a rare event and special analysis of the circumstances is discussed. However, it supports the necessity to carry out surveillance and research on this disease as recently reported by Arita et al.

Animals

Effect of episiotomy on the frequency of vaginal outlet lacerations.

The effect of midline episiotomy on the incidence and severity of vaginal outlet lacerations in spontaneous vaginal deliveries was studied in a retrospective manner by pairing women with and without episiotomy on the basis of age, parity and infant birth weight. When we controlled these three parameters, the patient with an episiotomy had fewer or less severe lacerations 33% of the time. However, when the episiotomy itself was counted as a laceration in the analysis, the number of patients benefitting from the procedure was reduced to 6%, with the nonepisiotomy patient having fewer lacerations than the episiotomy patient 78% of the time. The results suggest that for purposes of reducing outlet lacerations, the episiotomy should be used less often in spontaneous vaginal deliveries.

Adolescent

Pacemaker update.

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Arrhythmias, Cardiac

A comparison of inhaled powders of fenoterol and salbutamol in asthma.

The present study compares fenoterol and salbutamol powders (0.2 mg). Twenty-five children with frequent episodic asthma, aged 4-9 years, entered a double-blind, randomized, crossover, placebo controlled study. On each of three days fenoterol, salbutamol or placebo were given in random order. Lung function testing and other observations were made before and at set intervals up to 4 h after the treatments. Both inhaled powders increased the forced expired volume in 1 s and the maximum mid-expiratory flow rate significantly above placebo effect. No side effects were observed and there were no significant differences in bronchodilator efficacy between fenoterol and salbutamol.

Albuterol