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Biomedical subjects

S Hunter

Publications and source records attributed to S Hunter.

At least 217 records · Page 12Linked to original sources

Infradiaphragmatic total anomalous pulmonary venous connection to portal vein. Diagnostic implications of echocardiography.

A case of total anomalous pulmonary venous connection to the portal vein is described. The diagnosis was suspected clinically, supported by the echocardiogram, and confirmed by cardiac catheterisation, angiocardiography, and contrast echocardiography. An echo-free space lying behind the left atrium initially was thought to represent the common pulmonary vein. However, contrast echocardiography showed that this space was not the anomalous vein but probably an artefact. This paper shows that the origins of intracardiac echoes cannot always be assumed from a simple comparison of echocardiography with angiocardiographic or necropsy findings. In some cases it is necessary to introduce a marker into the echocardiogram which unequivocally originates from, and, therefore, localises, the structure under examination. Contrast echocardiography provides such a marker.

Angiocardiography↗

Diagnosis of ventriculo-arterial discordance (transposition of the great arteries) by contrast echocardiography.

The constant anatomical relation of the aortic arch and the pulmonary artery bifurcation permits echocardiographic differentiation of the two great arteries when viewed from the suprasternal notch. When this technique was employed with contrast echocardiography in 12 infants, 6 of whom had ventriculo-arterial discordance (transposition of the great arteries), it was possible to establish with certainty in all but 1 case which great artery was most directly connected to the systemic venous return.

Echocardiography↗

Echocardiography of primitive ventricle.

The angiocardiographic, echocardiographic, and, where available, the necropsy findings were correlated in 32 cases of primitive ventricle. Single probe echocardiography was shown to be a reliable and accurate technique for diagnosis of primitive ventricle; the ventricular and atrioventricular valve appearances were characteristic, and the outlet chamber was usually recognised when present, though it was not possible to say whether it was rigt or left sided. Abnormalities of the atrioventricular valves were more accurately shown by echocardiography than by angiocardiography though the two techniques were shown to be complementary in the overall diagnostic process.

Adolescent↗

Echocardiographic visualisation of the interatrial baffle after Mustard's operation.

Thirty children aged from 7 weeks to 14 years were examined by echocardiography after Mustard's operation for transposition of the great arteries. Discrete and persitent echoes were noted within the original left atrial cavity and contrast echocardiography was used to establish that these originated from the interatrial baffle. In the presence of caval channel obstruction, caused by malposition or shrinkage of the baffle, significant differences were seen in the echocardiographic appearances of the baffle, namely limitation of baffle motion, thickening, and multiplicity of the baffle echoes. These findings suggest that the technique may be of value in the postoperative assessment of patients with transposition of the great arteries.

Adolescent↗

The status of graduate-level social workers teaching in medical schools.

At present, relatively little national data are available concerning the involvement of social workers in medical education. This article presents the results of a study conducted recently to obtain a comprehensive, up-to-date profile of graduate-level social workers teaching in medical schools and to survey the opinions of medical school deans regarding their present and future status. Continuing research in this area is essential if we are to acquire a greater understanding of the contribution social workers make to contemporary medical education. Only then will we be better equipped to assess social work's potentials for the future and take those steps necessary to bring them to fruition.

Attitude↗

Ejection phase indices of left ventricular performance in infants, children, and adults.

A validatory study of quantitative single plane left ventricular cineangiography is presented, using human left ventricular casts ranging in size from 1.6 to 135 ml. Good correlation was found between actual and calculated volumes (r=0.967). 62 patient studies were carried out and the value of the usually calculated indices of left ventricular performance were compared to one another. Ejection fraction and mean rate of circumferential fibre shortening (mean Vcf) were found to be the best discriminators of abnormal left ventricular function, and, on the basis of the presented data, it is suggested that mean Vcf is the more sensitive index of left ventricular performance.

Adolescent↗

Validity of echocardiographic estimates of left ventricular size and performance in infants and children.

Echocardiography has been shown to be a reliable method for estimating left ventricular size and function in adults, but little attention has been paid to its application to infants and children. This paper describes a validatory study in 40 children aged between 4 days and 16 years. There was a significant correlation between angiocardiographic and echocardiographic estimates of left ventricular end-diastolic volume (r=0.76), left ventricular end-systolic volume (r=0.68), and ejection fraction (r=0.73). Left ventricular mean circumferential shortening rate (mean Vcf), however, gave the mostsignificant correlation (r=0.91). These findings indicate that while care must be exercised in interpreting indices of left ventricular size and performance derived from echocardiography, these measurements, and in particular mean Vcf, do offer a useful and reliable means of assessing left ventricular function in infants and children.

Adolescent↗

Estimation of pulmonary arterial pressure in the newborn: study of the repeatability of four Doppler echocardiographic techniques.

Despite the increasing use of Doppler echocardiographic (DE) techniques to determine pulmonary arterial pressure in the neonate undergoing intensive care, there have been no studies comparing their repeatability in this population. Our objective was to compare the repeatability of four such techniques in neonates. The study was conducted in two regional neonatal units serving the North East of England. Group A (repeatability between observers): Two experienced observers performed detailed DE examinations, one directly after the other. Group B (within observer repeatability/temporal variability): One observer performed two examinations 1 hour apart. Group A comprised 15 preterm babies (26-36 weeks' gestation, 975-2915 g), most with mild respiratory failure; 4 healthy term babies; and 7 with congenital heart disease, in whom tricuspid regurgitation (TR) only was measured. Their ages were 18 hours to 12 days. Group B comprised 11 babies aged 12-64 hours with moderate to severe respiratory failure; 10 were preterm (26-36 weeks, 785-2800 g). We recorded four measurements: (1) Peak velocity of TR in m/s; (2) peak left-to-right ductal flow velocity (PDAmax in m/s); (3) TPV/RVET ratio; and (4) PEP/RVET ratio, where TPV = time to peak velocity at the pulmonary valve, PEP = right ventricular preejection period, and RVET = right ventricular ejection time. The Bland-Altman analysis was used to produce the coefficient of repeatability (CR: 95% confidence limits of repeatability), also expressed as a repeatability index (CR/mean value) and as a number of "confidence steps"-a measure of sensitivity of the technique to hemodynamic change (range of values within the population/CR). Between-observer and within-observer repeatabilities were similar. Within-observer CR and index (%) results were for TR +/- 0.26 m/s (9%); for PDAmax, +/- 0.48 m/s (39%); TPV/RVET 0.1:1.0 (34%), PEP/RVET 0.12:1.00 (36%). TR and PDAmax had the largest number of confidence steps in the expected range of values (TR 8.5; PDA max 6.5; TPV/RVET 3.2; PEP/RVET 3.2). The most repeatable technique was TR, but PDAmax would also be useful for a serial study owing to the potential for large change. Systolic time interval ratios were less repeatable and likely to be less sensitive indicators of hemodynamic change.

Blood Pressure↗

Restriction fragment length polymorphism in four virulence-associated genes of Listeria monocytogenes.

We observed restriction fragment length polymorphism in 4 genes of Listeria monocytogenes associated with virulence. Using the polymerase chain reaction (PCR) and primers derived from published sequences, we amplified the following genes: hlyA coding for listeriolysin O, iap coding for a putative invasion-associated factor, mpl coding for a metalloprotease, and the prfA gene that positively regulates the hylA gene. PCR-amplified DNA were cut with several restriction endonucleases, and the restriction profiles from 29 strains, representing 6 serovars (serovars 1/2a, 1/2b, 1/2c, 3a, 3b and 4b) were compared. Based on these restriction profiles, the strains were categorized into 2 subgroups: one group contained all 10 strains of serovars 1/2a, 1/2c and 3a, the other group contained all 19 strains of serovars 1/2b, 3b and 4b. This division is in complete agreement with multilocus enzyme electrophoretic analysis data which divide the species into the same 2 subgroups. Whether the differences observed in the nucleotide sequences of the 4 virulence-associated genes for the 2 subgroups of L. monocytogenes represent salient variations in pathogenic mechanisms is not known.

DNA, Bacterial↗