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Biomedical subjects

C M Hall

Publications and source records attributed to C M Hall.

At least 91 records · Page 5Linked to original sources
PubMed1996

A new lethal chondrodysplasia with platyspondyly, long bone angulation and mixed bone density.

A fetus diagnosed by sonography at 20 weeks' gestation had multiple skeletal abnormalities. The main features were absent ossification of the skull and cervical and upper thoracic vertebral bodies; short, angulated femora, tibiae, radii and ulnae but normal humeri; platyspondyly; trident-shaped acetabular roofs; sclerotic bands on the iliac wings and scapulae; clavicular hooks; and overall, mixed bone density. We suggest that this is a new chondrodysplasia which, since the parents are first cousins, could follow autosomal recessive inheritance.

Abnormalities, Multiple↗
PubMed1995

A clinical and genetic study of campomelic dysplasia.

Campomelic dysplasia (CMD) is a rare skeletal disorder that is usually lethal. It is characterised by bowing of the lower limbs, severe respiratory distress, and many of the chromosomal (XY) males show sex reversal. Because of a number of reports of familial campomelic dysplasia it is considered to be inherited in an autosomal recessive manner. In this study, details of 36 patients with campomelic dysplasia were collected from genetic centres, radiologists, and pathologists in the United Kingdom. The chromosomal sex ratio was approximately 1:1. There was a preponderance of phenotypic females owing to sex reversal. Three quarters of the chromosomal males were sex reversed or had ambiguous genitalia. Three cases are still alive, two with chromosomal rearrangements involving chromosome 17q. The majority of the others died in the neonatal period. The 36 index cases had 41 sibs of whom only two were affected. Formal segregation analysis gave a segregation ratio of 0.05 (95% CI approximately 0.00 to 0.11). This excludes an autosomal recessive mode of inheritance. The data suggest a sporadic, autosomal dominant mode of inheritance. Patients with a chromosomal rearrangement involving 17q (q23.3-q25.1) show a milder phenotype. The molecular mechanism for the difference is still unknown.

Adolescent↗
PubMed1995

Wolcott-Rallison syndrome.

Two sibs with early onset diabetes and epiphysed dysplasia (Wolcott-Rallison syndrome) are described. The epiphyseal changes were radiologically apparent at 6 months of age in one of them, and both developed insulin dependent diabetes in the first few weeks of life. The clinical and radiological features of this syndrome are reviewed.

Diabetes Mellitus, Type 1↗
PubMed1995

Kinetic evidence for both a fast and a slow secretory pathway for apolipoprotein A-I in humans.

The kinetics of apolipoproteins A-I and A-II were examined in human subjects using leucine tracers administered intravenously. High density lipoproteins were separated and apoA-I and A-II were isolated. The specific activity or enrichment data for these apolipoprotein were analyzed by mathematical compartmental modeling. In 11 of 14 subjects studied with a bolus-injected [3H]leucine tracer, in 3 subjects studied similarly with [3H]leucine, and in one subject studied by primed dose, constant infusion of [3H]leucine, a rapidly turning-over apoA-I fraction was resolved. A similar component was observed in 7 of 10 studies of apoA-II. The apoA-I data were analyzed using a compartmental model (Zech, L.A. et al. 1983. J. Lipid Res. 24: 60-71) modified to incorporate plasma leucine as a precursor for apoprotein synthesis. The data permitted resolution of two apoA-I pools, one, C(2), turned-over with a residence time of less than 1 day, the other, C(1), a slowly turning-over pool, appeared in plasma after a delay of less than half a day. C(1) comprised the predominant mass of apoA-I and was also the primary determinant of the residence time of apoA-I. Although the mass of the fast pool, C(2), was considerably less than that of C(1), because of its rapid turnover, the quantities of apoA-I transported through this fast pathway were 2- to 4-fold greater. These kinetic studies indicate that apoA-I is secreted into both fast and slowly turning-over plasma pools. The latter is predominantly measured with radioiodinated apoA-I tracers. The data can be analyzed by postulating either separate input pathways to each of the pools or by assuming the fast pool is the precursor to the slow pool. Thus, apoA-I could be initially secreted as a family of particles that are rapidly cleared from plasma, and a portion of this apoprotein then reappears in a slowly turning-over pool that constitutes the major mass of apoA-I. The physiologic identity of these kinetically distinct apoA-I species is unknown; however, the fast pool of apoA-I demonstrated in these studies is strikingly similar to that seen in subjects with Tangier disease who lack the slow pool.

Apolipoprotein A-I↗
PubMed1995

Relative efficacy of hydrocortisone and methylprednisolone in acute severe asthma.

The relative clinical efficacy of different types of intravenous glucocorticosteroids in acute severe asthma is not clear in published studies. We conducted a randomised prospective study of asthma unit admissions over a 3-month period. Therapy consisted of 4-hourly nebulised salbutamol, intravenous aminophylline and either intravenous hydrocortisone 200 mg 4-hourly or intravenous methylprednisolone 125 mg 12-hourly. Three hundred and eighty-six patients were admitted to the asthma unit. After exclusions, 191 patients were included in the analysis (hydrocortisone--91, methylprednisolone--100). The groups were comparable in respect of baseline data. The median time to maximum peak expiratory flow rate was 19 hours for hydrocortisone and 23 hours for methylprednisolone (median test, P = 0.21). Median duration of asthma unit stay was 30 hours for hydrocortisone and 36 hours for methylprednisolone (median test, P = 0.01). A similar difference was evident on comparison of the trial medications in patients who had previously been on oral maintenance steroids. We conclude that, at the dosages selected, hydrocortisone is more effective than methylprednisolone in acute severe asthma.

Acute Disease↗
PubMed1994

New autosomal dominant form of spondyloepiphyseal dysplasia presenting with atlanto-axial instability.

We present a family with a radiologically distinct new form of autosomal dominant spondyloepiphyseal dysplasia, presenting with cervical instability and attendant neurological compromise and emphasise the radiological characteristics which delineate this condition. Cervical vertebral abnormalities, including malformation of the odontoid process, have been observed in some forms of spondyloepiphyseal dysplasia, but rarely lead to neurological sequelae, in contrast to the pedigree we describe.

Atlanto-Axial Joint↗
PubMed1994

Isolated dihydroxyacetonephosphate acyltransferase deficiency presenting with developmental delay.

A boy aged 21 months who was being investigated for developmental delay and failure to thrive was found to have punctate epiphyseal calcification. He had no evidence of rhizomelic shortening of the limbs or cataracts. Investigation revealed defective plasmalogen synthesis due to isolated deficiency of dihydroxyacetonephosphate acyltransferase (DHAP-AT). The parents were consanguineous and a sister was similarly affected, suggesting autosomal recessive inheritance. Hitherto, recessively inherited isolated DHAP-AT deficiency has only been described in patients with a phenotype similar to that of rhizomelic chondrodysplasia punctata. This report indicates that the same biochemical disorder can be associated with a less severe phenotype.

Acyltransferases↗
PubMed1994

Infantile fibrosarcoma: radiological and clinical features.

Two cases of infantile fibrosarcoma are described. This rare childhood malignancy of mesodermal origin usually affects the lower limbs, as it did in both of our cases. Previously, the only treatment option available involved some form of radical and often mutilating surgery. More recently, combination chemotherapy has given good results, with the effect that various imaging modalities have become important in assessing both the initial extent of disease and the response to treatment. Computed tomography has the advantage of demonstrating the amount of osseous involvement, but at the expense of a considerable dose of ionizing radiation. On the other hand, magnetic resonance imaging, with its multiplanar capacity, gives superior demonstration of breaching of tissue planes, which has important implications for planning of surgery. However, as in other soft tissue tumours, changes in signal characteristics with treatment have proved less specific than was originally anticipated.

Bone Resorption↗
PubMed1994

Modelling diagnostic skills in the domain of skeletal dysplasias.

The diagnostic model used in the medical expert system Skeletal Dysplasias Diagnostician (SDD) is discussed. The model aims to capture the diagnostic skills of domain experts. Such skills represent high level strategies which apply across different medical domains and hence the presented model is relatively generic. Preliminary evaluation of an earlier version of the diagnostic model, which yielded promising results, has led to a considerably improved model. A sample consultation given in an appendix illustrates most aspects of the current model. The paper concludes by giving the authors' practical insights into the knowledge engineering of medical diagnostic systems.

Bone Diseases, Developmental↗
PubMed1994

Organization, sequence, and expression of a gene encoding goldfish neurofilament medium protein.

The goldfish visual pathway displays a remarkable capacity for continuous neurogenesis, plasticity, and regeneration. The intermediate filament protein composition of this system differs from that of higher vertebrates, which lack the capacity for continued nerve growth and development. In an effort to determine how intermediate filament proteins are regulated during nerve growth, we isolated and characterized cDNA and genomic clones representing the goldfish neurofilament medium (NF-M) protein. The tissue-specific expression of goldfish NF-M mRNA was analyzed by RNase protection assays and by in situ hybridization. The expression of goldfish NF-M is qualitatively the same as in other species. Although the intermediate filament protein composition of the goldfish visual pathway is unusual when compared with higher vertebrates, the goldfish NF-M protein is similar to higher vertebrate NF-M proteins. In addition, the organization of the goldfish NF-M gene is identical to the NF-M genes in all other vertebrate species. In contrast, the promoter region of the goldfish NF-M gene has several potential regulatory sequences that are not found in the promoter regions of higher vertebrate NF-M genes.

Amino Acid Sequence↗
PubMed1994

Differential regulation of two classes of neuronal intermediate filament proteins during optic nerve regeneration.

The regulation of expression of two different types of neuronal intermediate filament proteins, ON1/ON2 and plasticin, was studied during optic nerve regeneration in the goldfish. During regenerative growth of optic axons, there is a rapid and dramatically increased expression of plasticin, a recently cloned, novel type III intermediate filament protein, in the retinal ganglion cells. At the time when the growing axons reinnervate the optic tectum, expression of plasticin declines and there is an increased expression of ON1 and ON2. This time course suggests that the target tissue participates in the regulation of these proteins. The aim of this study was to characterize the regulatory role played by the optic tectum. To address this issue, a repeated-crush paradigm was used whereby growing axons were hindered from reaching their target. It was found that in absence of tectal contact, the increased expression of ON1 and ON2 normally seen during regeneration was not induced. In contrast, expression of plasticin increased both in the presence and in the absence of tectal contact.

Animals↗
PubMed1994

Mycobacterial infection in renal transplant recipients.

STUDY OBJECTIVE: To determine the prevalence and presentation of mycobacterial infection as well as the influence on outcome in graft function and patient survival in renal transplant recipients at our institution. DESIGN: A retrospective review of case records of all renal transplant recipients from 1980 to 1992. SETTING: Groote Schuur Hospital, a large teaching hospital and regional tertiary referral center in Cape Town, South Africa. PATIENTS: During the period reviewed, 857 transplants were performed. The records of 487 patients who had remained in Cape Town were examined. RESULTS: There were 22 cases of mycobacterial infection (21 confirmed or presumed Mycobacterium tuberculosis and 1 unidentified Mycobacterium other than tuberculosis). In seven cases, immunosuppression had been intensified within 3 months of diagnosis. The median time from transplantation to diagnosis was 14 months (range, 2 to 74). Chest radiograph findings included consolidation (14), miliary pattern (4), pleural effusion (3), tuberculoma (2), cavitation (2), and hilar lymphadenopathy (1). Diagnosis of tuberculosis was made on sputum smears (eight), pleural biopsy specimen (two), fine-needle aspiration (one), and fiberoptic bronchoscopy in ten cases (brushings, eight; transbronchial biopsy specimen, three). Extrapulmonary tuberculosis (in addition to pulmonary tuberculosis) occurred in five patients (tuberculous meningitis, one; renal tuberculosis, one; and dissemminated infection, four). Five of the seven patients in whom immunosuppression had been intensified had concurrent infections; two of these died and the remainder returned to dialysis within 6 months. All but one patient received three antituberculosis drugs, including rifampin and isoniazid, for between 6 and 18 months. At the end of the period of review, 12 (59 percent) patients were alive, 10 with functioning grafts and 2 receiving dialysis. Four patients died while receiving antituberculosis treatment, but death was only directly related to tuberculosis in one case. CONCLUSIONS: Tuberculosis is an important infection in renal transplant recipients in Cape Town, but disseminated disease is less common than reported elsewhere.

Adult↗