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Biomedical subjects

J Wallis

Publications and source records attributed to J Wallis.

At least 55 records · Page 3Linked to original sources
PubMed1989

Prenatal diagnosis of Friedreich ataxia.

Friedreich ataxia is a progressive neurodegenerative disorder affecting the peripheral and central nervous systems. One in 50,000 of the population are affected by this recessively inherited disorder, with onset usually before puberty. The recent localization of the disease locus to chromosome 9 has made it possible to provide genetic counselling to families with at least one affected child. Tight linkage of the disease mutation to an anonymous DNA marker MCT112 (D9S15) has been shown with a pairwise lod score of 36.1 at 0 = 0. We report here the first prenatal diagnosis in Friedreich ataxia. Using MCT112 and the confidence interval approach, we have calculated risks for a fully informative family with one affected sib.

Amniocentesis↗
PubMed1989

Genetic homogeneity at the Friedreich ataxia locus on chromosome 9.

Classical Friedreich ataxia, a progressive, neurodegenerative disorder involving both the central and peripheral nervous systems, has been subclassified according to the observed clinical heterogeneity. The variations in the age at onset and in the spectrum and severity of symptoms have previously been interpreted as evidence of genetic heterogeneity. We have studied the linkage between the disorder and closely linked DNA markers in families of distinct ethnic origins, including the "typical" French-Canadians and the Acadian population of Louisiana. The disease in these two populations, both of continental French origin, has a very similar initial clinical picture. However, a marked difference in the rate of progression of the obligatory symptoms after 10 years of apparent disease is observed. A total of 553 individuals from 80 families with 202 affected members have been typed with the chromosome 9 marker MCT112, which we have previously shown to be closely linked to the disease locus. Evidence for linkage was observed in all families with the generation of a combined total lod score of 25.09 at a recombination fraction of theta = .00, providing strong evidence for genetic homogeneity at this locus for the classical form of this disease.

Canada↗
PubMed1988

Mapping of mutation causing Friedreich's ataxia to human chromosome 9.

Friedreich's ataxia is an autosomal recessive disease with progressive degeneration of the central and peripheral nervous system. The biochemical abnormality underlying the disorder has not been identified. Prompted by the success in localizing the mutations causing Duchenne muscular dystrophy, Huntington's disease and cystic fibrosis, we have undertaken molecular genetic linkage studies to determine the chromosomal site of the Friedreich's ataxia mutation as an initial step towards the isolation and characterization of the defective gene. We report the assignment of the gene mutation for this disorder to chromosome 9p22-CEN by genetic linkage to an anonymous DNA marker MCT112 and the interferon-beta gene probe. In contrast to the clinical variation seen for the disorder, no evidence of genetic heterogeneity is observed.

Chromosome Mapping↗
PubMed1988

[Heart-lung transplantation. Experience of Papworth Hospital. Apropos of 24 surgical cases].

Between April 5, 1984 and May 9, 1987, 24 patients underwent heart-lung transplantation for a variety of vascular and pulmonary diseases. Graft procurement being usually distant, the cardiopulmonary protection used was based on a simple hypothermic flush technique performed in donors prepared with prostacyclin. There was no primary graft deficiency and no intra-operative death. 17 patients are alive after a follow-up period of 1 to 41 months. The actuarial survival rate at 1 year was 77 p. 100. Late mortality was mainly due to cytomegalovirus infections. Immunosuppression relied on cyclosporine A and azathioprine with peri-operative use of antilymphocyte serum and corticosteroids. Early graft rejection episodes were treated with bolus intravenous methylprednisone. These episodes were detected from combined clinical, radiological, spirometric and histological data. Transbronchial lung biopsy was the reference examination for an objective diagnosis of lung rejection. In this series there was only one case of obliterative bronchiolitis (4 p. 100). This must be credited to the strategy used to detect rejection which seems to be the main factor of occurrence of this dangerous complication.

Adolescent↗
PubMed1987

Hormones and behavior of prepubertal and peripubertal chimpanzees.

Twenty-one chimpanzees ranging in age from 2.9 to 9.2 years at the midpoint of a study consisting of five 4-week blocks were studied behaviorally in four groups of five or six animals per group, balanced for age and sex. Blood samples for radioimmunoassay of follicle-stimulating hormone (FSH), luteinizing hormone, 17 beta-estradiol, testosterone, dehydroepiandrosterone (DHA), DHA sulfate (DHAS), and cortisol were obtained once each 4-week block. Sex differences were found only in the categories of play duration and initiative and genital inspection, all of which were greater for the males. Several categories (6) of play and other affiliative behaviors were negatively correlated with age and/or body weight for the males, whereas fewer of those categories (2) were so correlated in the females. Hierarchical behavior, genital inspection, solitary behavior other than play, and autogrooming were all positively correlated with age and/or body weight for the males, and only autogrooming for the females. FSH and testosterone levels and testicular volume were positively correlated with age and body weight in the males, whereas for the females cortisol was negatively correlated with body weight and only FSH and the ratios of DHA and DHAS to cortisol were positively correlated with age and/or body weight. Most of the behaviors that were significantly correlated with age and body weight for the males were also correlated in the same direction with FSH and testosterone levels and testicular volume, but not with DHA or DHAS levels. The data are consistent with the view that testosterone, but not the adrenal androgens DHA and DHAS, contributed to the behavioral development of the males. There were few significant correlations between hormones and behavior for the females and interpretation is not clear. The absence of age-related increases in DHA and DHAS of both the males and females, in contrast to the pattern of FSH (and testosterone for the males), supports the growing consensus that adrenarche and puberty are independent developmental processes. The absence of any strong correlations between behavior and levels of the adrenal androgens in either the males or females suggests that adrenarche per se is not a significant event in the behavioral development of chimpanzees.

Animals↗
PubMed1986

The use of hydroxocobalamin in the Schilling test.

Hydroxocobalamin and cyanocobalamin have been compared as the 'flushing dose' in the Schilling test. In healthy, haematologically normal subjects excretion of the test dose was greater following a hydroxocobalamin flushing dose than following a cyanocobalamin flushing dose, and to a lesser extent this was also true in patients requiring investigation. There were occasional discrepant results, but in general it appears that, although reference values differ, hydroxocobalamin is a suitable replacement for cyanocobalamin in the Schilling test.

Adult↗
PubMed1986

Identification of the p53 protein domain involved in formation of the simian virus 40 large T-antigen-p53 protein complex.

An expression vector utilizing the enhancer and promoter region of the simian virus 40 (SV40) DNA regulating a murine p53 cDNA clone was constructed. The vector produced murine p53 protein in monkey cells identified by five different monoclonal antibodies, three of which were specific for the murine form of p53. The murine p53 produced in monkey cells formed an oligomeric protein complex with the SV40 large tumor antigen. A large number of deletion mutations, in-frame linker insertion mutations, and linker insertion mutations resulting in a frameshift mutation were constructed in the cDNA coding portion of the p53 protein expression vector. The wild-type and mutant p53 cDNA vectors were expressed in monkey cells producing the SV40 large T antigen. The conformation and levels of p53 protein and its ability to form protein complexes with the SV40 T antigen were determined by using five different monoclonal antibodies with quite distinct epitope recognition sites. Insertion mutations between amino acid residues 123 and 215 (of a total of 390 amino acids) eliminated the ability of murine p53 to bind to the SV40 large T antigen. Deletion (at amino acids 11 through 33) and insertion mutations (amino acids 222 through 344) located on either side of this T-antigen-binding protein domain produced a murine p53 protein that bound to the SV40 large T antigen. The same five insertion mutations that failed to bind with the SV40 large T antigen also failed to react with a specific monoclonal antibody, PAb246. In contrast, six additional deletion and insertion mutations that produced p53 protein that did bind with T antigen were each recognized by PAb246. The proposed epitope for PAb246 has been mapped adjacent (amino acids 88 through 109) to the T-antigen-binding domain (amino acids 123 through 215) localized by the mutations mapped in this study. Finally, some insertion mutations that produced a protein that failed to bind to the SV40 T antigen appeared to have an enhanced ability to complex with a 68-kilodalton cellular protein in monkey cells.

Animals↗
PubMed1985

Correlation of the exercise ST/HR slope with anatomic and radionuclide cineangiographic findings in stable angina pectoris.

A rate-related change in ST-segment depression with exercise (ST/HR slope) of 6.0 microV/beat/min or more has been proposed as an accurate predictor of 3-vessel coronary artery disease (CAD). To further assess the accuracy and functional correlates of this method, exercise electrocardiograms were compared with radionuclide rest and exercise left ventricular (LV) ejection fraction (EF) and angiography in 35 patients with stable angina. The ST/HR slope was significantly increased in patients with 3-vessel CAD. An ST/HR slope of 6.0 or more identified 3-vessel CAD with a sensitivity of 89% and specificity of 88%. The predictive value for 3-vessel CAD was 73% owing to the presence of 3 false-positive slopes. The patients from whom these slopes were derived had functionally severe 2-vessel CAD, with an average decrease in exercise LVEF of 13%. Two of these 3 had additional left main CAD and the third has unsuspected additional aortic regurgitation. For the entire group, the exercise ST/HR slope was linearly related to the exercise change in LVEF (r = -0.55, p less than 0.001). Mean exercise change in LVEF for stable angina patients with ST/HR slopes of 4.5 or more was significantly different from that for patients with lower ST/HR slopes (-12 +/- 1% vs + 2 +/- 2%, p less than 0.0001). Thus, the ST/HR slope is both sensitive and specific for the identification of 3-vessel CAD, and high ST/HR slopes in patients with less extensive anatomic disease may predict functionally severe ischemia.

Adult↗
PubMed1985

Iodine-131 metaiodobenzylguanidine for the locating of suspected pheochromocytoma: experience in 400 cases.

The efficacy of the newly developed pheochromocytoma-seeking radiopharmaceutical, [131I]MIBG, was examined in the first 400 patients (441 studies) investigated for suspected pheochromocytoma at our institution. The results of [131I]MIBG scintigraphy were classified as true positive, false positive, true negative, and false negative. Using this classification the sensitivity was found to be 78.4% in primary, sporadic pheochromocytoma, 92.4% in malignant pheochromocytoma, and 94.3% in familial pheochromocytoma giving an overall sensitivity of 87.4%. The specificity was 98.9% in primary, sporadic pheochromocytoma, 100% in malignant pheochromocytoma, and 100% in familial pheochromocytoma. The overall specificity was 98.9%. Iodine-131 MIBG scintigraphy was thus found to be a safe, noninvasive, and efficacious technique for the location of pheochromocytomas, especially for those arising from nonadrenal sites, recurring postoperatively, and exhibiting malignant metastatic disease. We find that, where available, [131I]MIBG scintigraphy is the study of choice to initiate the location of suspected pheochromocytoma.

3-Iodobenzylguanidine↗
PubMed1984

[Hormonal and compartmental correlates during adrenarche in the chimpanzee].

Ten male and eleven female Chimpanzees from three to nine years of age were studied to establish possible correlations between behavioral changes and hormonal changes peculiar to adrenarche and the pre-puberty period. Most of the thirteen behaviors studied varied with age, body weight and hormones. For the males, the correlations were significant statistically for age, weight and plasma concentration of testosterone and of FSH. The correlations for the females were more often not significant statistically. In ten out of the thirteen behaviors for the female, however, the correlations with the sulfate of plasma dehydroepiandrosterone were in the same direction as those observed for the males with testosterone.

Adrenal Cortex↗
PubMed1981

[Ultrasound diagnosis of muscle haematomas in haemophiliac patients (author's transl)].

Ultrasound was used for the diagnosis of muscle haematomas in seventeen patients with congenital clotting abnormalities. Fifteen patients had haematomas in the extremities or the gluteal muscles, whereas in four cases there was retroperitoneal bleeding. In three of the nineteen examinations there was no sonographic evidence of recent bleeding at the first attempt, but in sixteen cases the size, localisation and relationship to neighbouring organs could be demonstrated. It was possible to distinguish between localised haematomas and diffuse ones. Comparison of the two sides was used with semi-quantitative evaluation of the amplitude profile. The condition in the extremities favours ultrasound examination and makes it possible to use high frequencies in order to achieve better resolution; the diagnosis of bleeding into the retroperitoneal space may be difficult. At times other methods of examination, particularly computer tomography, may have to be used.

Adolescent↗