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Biomedical subjects

A C Cook

Publications and source records attributed to A C Cook.

10 recordsLinked to original sources
PubMed1995

Morphology of the sinus node in human and mouse hearts with isomerism of the atrial appendages.

BACKGROUND: The location of the sinus node is known to be at best abnormal, or at worst unknown, in patients with isomerism of the morphologically left atrial appendage. In contrast, the sinus node is known to be an excellent histological marker of the morphologically right appendage, being duplicated in those with right isomerism. The aim of the study was to investigate this condition further in fetal human and mouse hearts. METHODS: Serial histological sections of the area anticipated to contain the sinus node were studied in hearts with isomerism of the atrial appendages taken from 14 human fetuses and 13 iv/iv mice, using 12 mouse hearts with normally arranged or mirror imaged atrial chambers for controls. RESULTS: All hearts with isomerism of the right appendages (two human and four mouse) had bilateral sinus nodes. The cases with isomerism of the left appendages (12 human and nine mouse) showed absence of a recognisable sinus node except in four cases (19%) in which a small remnant of the node was found. In three of these cases, it was related postero-inferiorly to the superior cavoatrial junction. CONCLUSIONS: The concept of isomerism of the atrial appendages is endorsed by findings on the morphology of the sinus node, this being the most reliable histological criterion for existence of a morphologically right atrium. A small proportion of hearts with left isomerism had a structure resembling the sinus node, but it was hypoplastic and displaced postero-inferiorly, distant from its expected position had the hearts possessed an incompletely formed morphologically right appendage.

Adult↗
PubMed1995

Echocardiographic-anatomical correlations in aorto-left ventricular tunnel.

OBJECTIVE: To investigate the echocardiographic, morphological, and histological appearances of aorto-left ventricular tunnel observed in four fetal hearts and compare the findings with those reported in older patients with the malformation. BACKGROUND: Previous studies have concentrated on clinical features of the malformation from birth to adult life and have speculated on either its embryological formation or its acquisition during late intrauterine life. The presentation of a large series of cases in fetal life is a unique opportunity to study the malformation at an early stage in its natural course. METHODS: A retrospective study was performed of four cases of aorto-left ventricular tunnel discovered among 872 cases of congenital abnormalities diagnosed at a tertiary centre for fetal echocardiography. Detailed echocardiographic and anatomical observations were made of the malformation as identified during fetal life. The precise anatomical arrangement was determined and compared with previous descriptions found in journals published in English. RESULTS: In fetal life, as after birth, the malformation is characterised by enlargement and hypertrophy of the left ventricle, enlargement of the aortic root, and free regurgitation at the level of the aortic valve. Anatomical abnormalities are found at the aortic ventriculoarterial and sinutubular junctions as well as in the intervening aortic wall. These are unrelated to necrosis, ischaemia, or the presence of mucopolysaccharides. CONCLUSIONS: The lesion is a developmental abnormality that should be reliably diagnosed by fetal echocardiography combined with colour flow Doppler echocardiography during the mid-trimester. The exact anatomical relations clarified by this study are pertinent to diagnosis and subsequent surgical correction.

Aorta↗
PubMed1992

Cardiac tumours in intrauterine life.

Since 1980, 11 examples of cardiac tumour have been detected in the fetus out of a total of 794 congenital cardiac malformations. Patients were referred because of fetal hydrops in two, a family history of tuberous sclerosis in two, and because of the detection of a tumour mass during a scan at the local hospital in seven. The gestational age range at presentation was from 20-34 weeks. Of eight fetuses where death occurred, the histological type was rhabdomyoma in seven and teratoma in one. In seven cases, the lesion appeared single and in four there were multiple tumours. In two of the cases of rhabdomyoma, other family members had evidence of tuberous sclerosis. Termination of pregnancy took place in four cases; of seven continuing pregnancies, spontaneous intrauterine death occurred in four, and three children are still alive. Two of the three survivors has the clinical picture of tuberous sclerosis. The last case is as yet only 1 month old. In summary, even where the lesion is single, the most likely diagnosis in fetal cardiac tumour is rhabdomyoma, with associated tuberous sclerosis. However, the characteristic features of this latter condition may not become evident until some months after birth.

Echocardiography↗
PubMed1992

Use of casts in the necropsy diagnosis of fetal congenital heart disease.

OBJECTIVE: To evaluate a casting technique in the interpretation of fetal cardiac anatomy. DESIGN: In 32 fetuses, the echocardiographic and cast features were compared and correlated. PATIENTS: Three normal fetal heart specimens from spontaneous abortuses and 32 specimens from spontaneous or induced abortions with congenital heart malformation. RESULTS: There was close correlation between the echocardiographic and anatomical features in 32 abnormal fetuses studied. In some, additional features of diagnosis could be displayed on the cast and the relative sizes of the cardiac structures could be appreciated and defined. CONCLUSIONS: With increasing echocardiographic detection of congenital heart disease in early prenatal life, an increasing number of fetal heart specimens of small size are dissected for pathological confirmation. The use of silicone rubber casts to reproduce the internal anatomy proved a useful addition to dissection, providing a three dimensional model of the cardiac defect.

Autopsy↗
PubMed1992

Correlation between echocardiographic and morphological investigations of lesions of the tricuspid valve diagnosed during fetal life.

OBJECTIVE: To assess the degree of agreement between the fetal echocardiographic and postmortem examination of hearts from fetuses with severe malformations of the tricuspid valve. DESIGN: A retrospective study to analyse echocardiographic recordings and make comparisons with postmortem findings. SETTING: Tertiary referral centre for fetal echocardiography. Institute for cardiac morphology. PATIENTS: 19 cases shown to have severe malformation of the tricuspid valve by fetal echocardiography that died in the prenatal or neonatal period. MAIN OUTCOME MEASURES: Correlations between morphology and measurements made at echocardiography and necropsy. RESULTS: The echocardiographic diagnosis was Ebstein's malformation in seven and tricuspid valvar dysplasia in 12 fetuses. These findings were confirmed in six and eight cases at necropsy. In one false positive diagnosis of Ebstein's malformation, necropsy showed dysplasia of the leaflets of the tricuspid valve without displacement. In four cases with the echocardiographic diagnosis of valvar dysplasia, necropsy showed displacement, the hallmark of Ebstein's malformation. Associated malformations that are known to worsen prognosis were predicted correctly by echocardiography. Taking the mean duration of four weeks between echocardiographic and postmortem investigations, both methods showed cardiomegaly causing lung hypoplasia, right atrial dilatation, and relative hypoplasia of the pulmonary trunk, morphometric factors that may be responsible for the poor outcome. Mostly good agreement existed between the echocardiographic and postmortem measurements if cases with an interval of more than eight weeks between the measurements were excluded. CONCLUSION: Fetal echocardiography was proved to be a reliable technique in differentiating the variants of tricuspid valvar disease, in diagnosing associated cardiac lesions, and in predicting quantitative factors that can define the subsequent outcome.

Ebstein Anomaly↗
PubMed1991

Tumor suppressor p53: analysis of wild-type and mutant p53 complexes.

It has been suggested that the dominant effect of mutant p53 on tumor progression may reflect the mutant protein binding to wild-type p53, with inactivation of suppressor function. To date, evidence for wild-type/mutant p53 complexes involves p53 from different species. To investigate wild-type/mutant p53 complexes in relation to natural tumor progression, we sought to identify intraspecific complexes, using murine p53. The mutant phenotype p53-246(0) was used because this phenotype is immunologically distinct from wild-type p53-246+ and thus permits immunological analysis for wild-type/mutant p53 complexes. The p53 proteins were derived from genetically defined p53 cDNAs expressed in vitro and also from phenotypic variants of p53 expressed in vivo. We found that the mutant p53 phenotype was able to form a complex with the wild type when the two p53 variants were cotranslated. When mixed in their native states (after translation), the wild-type and mutant p53 proteins did not exhibit any binding affinity for each other in vitro. Under identical conditions, complexes of wild-type human and murine p53 proteins were formed. For murine p53, both the wild-type and mutant p53 proteins formed high-molecular-weight complexes when translated in vitro. This oligomerization appeared to involve the carboxyl terminus, since truncated p53 (amino acids 1 to 343) did not form complexes. We suggest that the ability of the mutant p53 phenotype to complex with wild type during cotranslation may contribute to the transforming function of activated mutants of p53 in vivo.

Animals↗
PubMed1991

Left ventricular dysfunction in the fetus: relation to aortic valve anomalies and endocardial fibroelastosis.

OBJECTIVE: To examine the relation between a characteristic form of left ventricular dysfunction in the fetus and abnormalities of the aortic valve and endocardial fibroelastosis of the left ventricle. DESIGN: A retrospective study to examine the correlation between echocardiographic findings in the fetus and postnatal or necropsy findings. SETTING: Tertiary referral centre for fetal echocardiography. PATIENTS: Thirty fetuses showing a characteristic echocardiographic picture of left ventricular dysfunction. MAIN OUTCOME MEASURES: The relation between the prenatal echocardiographic features and the postnatal and necropsy findings. RESULTS: At presentation the size of the left ventricular cavity was normal or enlarged in all cases. The measurements of the orifice of the aortic root and mitral valve were either normal or small for the gestational age. The echocardiographic diagnosis made at presentation was critical aortic stenosis in all cases. At necropsy or postnatal examination the aortic valve was dysplastic and stenotic in 15 cases and the left ventricle had become hypoplastic in one of these. Aortic atresia was present in seven patients, three of whom had a hypoplastic left ventricle. In six patients the aortic valve was bicuspid although not obstructive. One of these patients had hypoplasia of the aortic arch and one had a hypoplastic left ventricle but in the remaining four patients endocardial fibroelastosis of the left ventricle was the only abnormality found. No follow up information was available in two. Of 26 patients for whom there was postmortem information, 24 had evidence of some degree of endocardial fibroelastosis of the left ventricle. Sequential observations showed that five cases developed into the hypoplastic left heart syndrome. CONCLUSIONS: This type of left ventricular dysfunction in the fetus is the result of an overlap of diseases, including primary left ventricular endocardial fibroelastosis, critical aortic stenosis, and the hypoplastic left heart syndrome.

Aortic Valve↗
PubMed1984

Decrease in timed balance test scores with aging.

This study investigated whether 184 volunteers from 20 to 79 years of age could perform eight timed balance tests and examined the relationship between test performance and age. All subjects were able to balance with their feet together and eyes closed for 30 seconds. The ability to balance on the right and left legs did not differ significantly. Subjects over 60 years of age were unable to balance on one leg, particularly when their eyes were closed, for as long a period as younger subjects. The Pearson product-moment and Spearman correlations of age and duration of one-legged balance were -.65 and -.71 (eyes opened) and -.79 and -.75 (eyes closed). The findings suggest that when timed balance tests are performed as a part of a patient's neurologic examination, the results should be interpreted in light of the patient's age. Information is provided to assist in this interpretation.

Adult↗