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Biomedical subjects

C McKay

Publications and source records attributed to C McKay.

At least 73 records · Page 4Linked to original sources
PubMed1980

Failure of penicillin to eradicate group A streptococci during an outbreak of pharyngitis.

In an outbreak of group A streptococcal pharyngitis in a semi-closed community, 42 (25%) of 169 courses of antibiotic therapy failed to eradicate the organism. 16 (19%) of 85 individuals treated with intramuscular benzathine penicillin G and 9 (19%) of 47 patients treated with an oral antibiotic (penicillin V or erythromycin) continued to harbour the same serotype of group A streptococcus. 12 (48%) of 25 persons remained treatment failures after re-treatment; even after a third course of treatment 5 of 12 (42%) still harboured the organism. Neither antibiotic resistance of the epidemic strain nor reacquisition of the organism from contacts could be implicated as causes. The data suggest that many who did not respond to treatment were streptococcal carriers and raise the possibility that it is more difficult to eradicate the organism from the carrier than from the acutely infected individual.

Adult↗
PubMed1980

The immunologic response to group A streptococcal upper respiratory tract infections in very young children.

The immunologic responses to streptolysin O and streptococcal deoxyribonuclease B were evaluated in children with group A streptococci recovered from the upper respiratory tract to re-examine the hypothesis that a limited capacity to respond to group A streptococcal infection may explain the rare occurrence of acute rheumatic fever in very young children. ASO and anti-DNase B titers were determined on serial bleedings from a total of 301 individuals (52 less than or equal to 3 years; 249 older than 3 years). Very young children with group A streptococcal upper respiratory tract infections had an immunologic response to SO greater than the response in older children as reflected by the magnitude of the antibody rise, and comparable to the ASO response in older children as measured by the percentage showing a significant titer rise. Similar analyses of the anti-DNase B responses showed the response in young children to be comparable to those of the older group. Clinical manifestations of group A streptococcal upper respiratory tract infection in very young children differ from those observed in older children and have not changed significantly in the past several decades. These data suggest that the infrequent occurrence of acute rheumatic fever in very young children is not due to a difference in antibody response to streptolysin O or streptococcal DNase B.

Adolescent↗
PubMed1978

Heat and mass transfer of a thermal indicator in pulsatile flow through the cardio-pulmonary system. I. Modeling.

The construction of a physico-mathematical model which describes the mechanism of indicator dispersion in the circulation and which fits the thermal dilution curves (TDC) is presented. Because of its more evident physical meaning, formulation of the problem in terms of heat and mass transfer is preferred to stochastic theory. Hypotheses necessary to simplify the general system of governing equations are clearly defined and discussed. This deductive method leads to a one-dimensional convective heat transfer model in which pulsatility and form of injection appear naturally. Simulations of TDC in constant and pulsatile flow cases are performed on a digital mini-computer which demonstrates the model's ability to represent different experimental or clinical observations. This will facilitate hemodynamic parameter identification from TD techniques and will increase the accuracy of this identification.

Aorta↗
PubMed1978

Heat and mass transfer of a thermal indicator in pulsatile flow through the cardio-pulmonary system. II. Identification of cardiac output.

Hamilton's celebrated formula for cardiac output measurement is simple but its validity is dependent on several methodologic requirements which are not generally fulfilled, particularly in thermal dilution. A quite different method, based on a physico-mathematical model of the indicator dispersion in the circulation, is proposed. It allows direct derivation of cardiac output once the model's parameters have been identified. Combined deconvolution and least squares procedures are used with truncated data for this identification. Numerical tests and application to clinical observations are presented. Both limitations and possibilities of further developments in estimation of pulsatile flow conditions from TD technique are discussed.

Blood Circulation↗
PubMedDate not supplied

Database Conference January 27-30, 2000, Washington D.C.--Do existing databases answer clinical questions about geriatric cardiovascular disease and stroke?

EXECUTIVE SUMMARY: Most randomized, controlled trials evaluating the effectiveness of pharmaceutical, surgical, and device interventions for the prevention and treatment of cardiovascular disease have excluded patients over 75 years of age. Consequently, the use of these therapies in the older population is based on extrapolation of safety and effectiveness data obtained from younger patients. However, there are many registries and observational databases that contain large amounts of data on patients 75 years of age and older, as well as on younger patients. Although conclusions from such data are limited, it is possible to define the characteristics of patients who did well and those who did poorly. The goal of this conference was to convene the principal investigators of these databases, and others in the field of geriatric cardiology, to address questions relating to the safety and effectiveness of treatment interventions for several cardiovascular conditions in the elderly. Seven committees discussed the following topics: (I) Risk Factor Modification in the Elderly; (II) Chronic Heart Failure; (III) Chronic Coronary Artery Disease: Role of Revascularization; (IV) Acute Myocardial Infarction; (V) Valve Surgery in the Elderly; (VI) Electrophysiology, Pacemaker, and Automatic Internal Cardioverter Defibrillators Databases; (VII) Carotid Endarterectomy in the Elderly. The chairs of these committees were asked to invite principal investigators of key databases in each of these areas to discuss and prepare a written statement concerning the available safety and efficacy data regarding interventions for these conditions and to identify and prioritize areas for future study. The ultimate goal is to stimulate further collaborative outcomes research in the elderly so as to place the treatment of cardiovascular disease on a more scientific basis.

Aged↗
PubMedDate not supplied

Motor/learning difficulties and the family.

The work reported here, which has as its central concern family dynamics and relationships, is part of a wider study of 31 children with motor/learning difficulties. All the children were attending an Occupational Therapy Department and had been assessed as having motor/learning difficulties. Descriptions of family background, structure and composition are provided and findings on conjugal, parent/child, sibling and extended family relationships presented. Characteristic patterns of family interaction are identified and factors affecting family cohesion discussed.

Achievement↗
PubMedDate not supplied

The identification and treatment of motor/learning difficulties: parents' perceptions and the role of the therapist.

The diagnostic experience of 31 children, assessed as having motor/learning difficulties, attending an occupational therapy department within a children's hospital, was investigated. The study demonstrates the difficulty of specific identification of perceptuomotor problems. Close examination of the children's individual diagnostic pathways revealed a high number of health-care professional contacts and the fact that frequently there were lengthy gaps between parental (and sometimes professional) suspicions and final confirmation. The children's diagnostic experiences prior to starting treatment were varied and involved, and no one single route was predominant. The rationale for occupational-therapy assessment and treatment of this disorder is described, and parental perceptions of its effect are discussed. The findings suggest that an important part of therapeutic intervention may be increasing children's self-confidence and reducing intra and extra family tensions. Fewer behavioural problems were reported once treatment had commenced. It was concluded that an important part of the therapist's role was to provide information and support for parents and to liaise with school teachers, in addition to treating the children themselves.

Child↗
PubMedDate not supplied

Inaccuracy of Doppler estimates of pulmonary artery pressure using pulmonary flow acceleration time.

Pulsed Doppler echocardiography was used to estimate mean pulmonary artery pressure (PAP), mean pulmonary artery wedge pressure PAWP) and the changes in PAP and PAWP following intervention in an unselected population composed of 60 patients undergoing routine diagnostic cardiac catheterization. Simultaneous Doppler and strain gauge manometry recordings of PAP and PAWP were interpreted by independent observers in a blinded fashion. A first set of measurements was obtained before left ventricular angiography and a second soon after the injection of contrast dye. The mean Doppler PAP and PAWP were derived from acceleration time and calculated using previously published regression equations: PAP = -0.45 x AcT + 79, PAWP = 57 - 0.39 x AcT. At rest, PAP measurements by strain gauge manometry ranged from 13 to 45 mmHg with a mean of 24 +/- 10 (one standard deviation); PAWP ranged from 2 to 40 mmHg with a mean of 15 +/- 6. Following left ventricular angiography, the PAP ranged from 18 to 50 mmHg with a mean of 29 +/- 7; PAWP ranged from 6 to 45 mmHg with a mean of 20 +/- 7. The values obtained by pulsed Doppler before and after intervention correlated poorly with those obtained by strain gauge manometry (r = 0.09 and 0.26 for PAP; r = 0.03 and 0.25 for PAWP).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗