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Biomedical subjects

S F Cahalane

Publications and source records attributed to S F Cahalane.

At least 19 recordsLinked to original sources
PubMed1994

Molecular analysis of PKU in Ireland.

Classical phenylketonuria (PKU: McKusick No. 261600) is caused by mutations occurring at the phenylalanine hydroxylase (PAH) locus on chromosome 12 and has a prevalence in Ireland of 1 in 4500. We examined 304 independent alleles from 350 patients for the presence of six mutations and have characterized VNTR alleles within the minisatellite region 3' to the PAH gene in patients carrying the most prevalent mutation. R408W was the most common mutation found, with a relative frequency of 42%. All other mutations had relative frequencies of < 10%. VNTR analysis showed that the R408W mutation is associated with the VNTR-8 allele in the Irish population, indicating that R408W is associated with RFLP haplotype 1. This differs from that reported from eastern Europe where R408W is associated with RFLP haplotype 2/VNTR-3; an observation which has led several groups to propose a Balto-Slavic origin for this mutation. These results support the hypothesis of a second, independent founding event for the R408W mutation on an RFLP haplotype 1 VNTR-8 chromosome background in the Irish/Celtic population.

Gene Frequency↗
PubMed1990

Birth weight and pathogenesis in phenylketonuria.

The birthweights of an ethnically homogeneous sample of infants with phenylketonuria, their unaffected siblings, and control infants were compared after adjusting for the effects of: mother's age, mother's date of birth, mother's height and obstetric history, the length of gestation, the infant's sex, the place and date of birth. There were no significant differences between the infants with phenylketonuria and their unaffected siblings either in adjusted or unadjusted birthweights. Control infants had slightly, but statistically significant, greater adjusted and unadjusted birthweights than the combined phenylketonuria and unaffected sibling groups. This effect of the phenylketonuria gene is a previously unreported finding but unlikely to be related to the pathogenesis of phenylketonuria. Our results do not provide support for the "justification" hypothesis that the mental and neurological defects in phenylketonuria result from prenatal tyrosine deprivation which would be reflected in lower birthweights.

Birth Weight↗
PubMed1989

Abnormal patterns of pulmonary neuroendocrine cells in victims of sudden infant death syndrome.

Ventilatory dysfunction has become the main focus of current research in sudden infant death syndrome (SIDS). This has been correlated with structural abnormalities in the carotid body and respiratory nuclei of the brainstem. In recent studies, the denervating effect of asphyxial brainstem dysfunction on the pulmonary neuroendocrine cells, which probably function as chemoreceptors, was demonstrated and prompted the following study. The pulmonary neuroendocrine system was evaluated in 25 victims of SIDS and 20 control infants, ranging in age from 3 weeks to 7 months and 1 to 12 months, respectively. The pulmonary neuroendocrine cells were stained by the Churukian-Schenk method and the neuroendocrine cell-positive airway values expressed as a percentage of the total number of airways. The range of positive airway values for victims of SIDS was 2% to 97% with a median of 73%. In contrast, the range for the control infants was 1% to 44% with a median of 25.5%. The SIDS victims' percentage was significantly greater than the control infants' percentage (P less than .0001). The number of pulmonary neuroendocrine cells in positive airway was also increased among SIDS victims compared with control infants. The altered pulmonary neuroendocrine cell pattern could be attributable to either brainstem dysfunction or chronic hypoxia. These explanations are not, however, mutually exclusive of one another; in fact, it is possible that both mechanisms may be operative.

APUD Cells↗
PubMed1988

Renal dysplasia--a clinicopathological review.

A review of 15 cases of unilateral renal dysplasia is presented. Seven patients came to medical attention with urinary tract infection. Only 4 presented with an abdominal mass. Eight patients were found to have ipsilateral ureteric anomalies and 4 of these also had contralateral ureteric problems. Five patients had extra-renal anomalies and these included Turner's syndrome, scoliosis and congenital dislocation of the hip. Histological examination, in all cases, revealed the presence of primitive ducts surrounded by concentric layers of cellular mesenchyme. Metaplastic cartilage was noted in only 7 of the 15 cases.

Adolescent↗
PubMed1987

Malignant rhabdoid tumour of soft tissue. An ultrastructural and immunohistological study of a pelvic tumour.

A case of extrarenal malignant rhabdoid sarcoma arising in the pelvic soft tissues of a 12-year-old girl is described. By routine light microscopy the tumour resembled, in some areas, an embryonal rhabdomyosarcoma and, in other areas, a neuroblastoma. Electron microscopy revealed characteristic cytoplasmic aggregates of intermediate filaments, often with central clusters of organelle membranes surrounded by these filaments. Immunohistochemical stains showed strong cytoplasmic reactivity for vimentin. Staining for cytokeratin, myoglobin, desmin, neurofilaments, neurone specific enolase, S-100 protein and leucocyte common antigen was negative. A histogenetic origin from primitive mesenchymal cells is favoured. We strongly support the use of electron microscopy for the definitive diagnosis of small round cell undifferentiated sarcomas of childhood.

Child↗
PubMed1980

Screening for congenital hypothyroidism in the Republic of Ireland.

A national pilot study for detecting congenital hypothyroidism by radioimmunoassay of thyroid-stimulating hormone concentrations in dried blood was incorporated into the newborn screening programme in Ireland on 1 August 1979. The programme has been monitored by a steering committee and follows the guidelines set by the European Society of Paediatric Endocrinologists. During the first 12 months 76 224 infants were screened and 19 cases confirmed, giving an incidence of 1:4012. Fifty infants (0.07%) were recalled for a serum sample, though most of the recalls (31; 0.04%) occurred during the first three months, before the methodology had become established. No case was detected clinically. At recall only three of the 19 affected infants had obvious features, and nine inconspicuous features. Organisation was directed at early diagnosis and treatment, the mean age at beginning treatment being 15 days. These results confirm the efficacy of screening for congenital hypothyroidism and suggest that capital and running costs will be offset by savings in maintenance treatment of untreated patients. Screening does not, however, remove the need for continued vigilance, and clinicians should request thyroid-function tests in any suspected case.

Age Factors↗
PubMed1975

Fulminant meningococcal septicaemia. A hospital experience.

In the first 5 months of 1975, 12 cases of meningococcal septicaemia were seen at a children's hospital where in previous years the condition was seen only sporadically. 3 of these children were dead on admission, 5 died shortly after admission, and 4 responded to treatment. Neisseria meningitidis was recovered from cerebrospinal fluid or blood or both in all cases, and the clinical illness was characterised by fever, prostration, and cutaneous purpura of abrupt onset. There were no significant previous illnesses, no recognisable prodromata, and, bacteriology apart, no pattern of laboratory results. There was a suggestion of centre-city clustering in the home background, although 2 of the patients came from rural areas. At necropsy gross adrenal haemorrhage was found in 6 of the 8 fatal cases, and upper gastrointestinal bleeds in the 5 deaths which were not sudden.

Autopsy↗
PubMed1975

Phenylketonuria as a balanced polymorphism: the nature of the heterozygote advantage.

Mothers of children with phenylketonuria have a significantly lower miscarriage rate than a matched control population in Ireland and west Scotland. This protective effect of the gene against some factor causing foetal death would seem to constitute a heterozygote advantage which might account for the previously observed polymorphism for phenylketonuria. It is suggested that the decrease in foetal mortality is mediated by the higher concentration of phenylalanine in the heterozygous mother's blood, but that this is not a simple nutritional effect of an increased supply of an essential amino acid leading to increased protein deposition.

Abortion, Spontaneous↗