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Biomedical subjects

F J Stewart

Publications and source records attributed to F J Stewart.

At least 19 recordsLinked to original sources

The adult phenotype in Costello syndrome.

We report clinical findings in 17 adults with Costello syndrome ranging in age from 16 to 40 years. Two patients in this series have had bladder carcinoma, the only malignancy reported to affect adults with Costello syndrome. Benign tumors included multiple ductal papillomata in two women, and a fourth ventricle mass in one man, thought to be a choroid plexus papilloma. Endocrine problems in this series were osteoporosis, central hypogonadism, and delayed puberty. Other health problems were symptomatic Chiari malformations in three patients. Four patients had adult-onset gastro-esophageal reflux, three of whom had Chiari malformations. Fourteen adults had mild to moderate intellectual disability with three individuals having severe intellectual disability; 15 individuals attained some reading and writing skills and 14 showed ongoing acquisition of new skills into adulthood. On the basis of this data, we recommend that neuro-imaging be considered in adults with Costello syndrome if they develop symptoms suggestive of a Chiari malformation. In the event of pubertal delay, endocrine investigations are indicated and hormone treatment may be required. Bone density assessments should be performed in adults with Costello syndrome, particularly in those with pubertal abnormalities. Screening for microscopic hematuria as a marker for bladder carcinoma may be indicated, although this requires further evaluation.

Abnormalities, Multiple↗

Methyl-specific DNA binding by McrBC, a modification-dependent restriction enzyme.

McrBC, a GTP-requiring, modification-dependent endonuclease of Escherichia coli K-12, specifically recognizes DNA sites of the form 5' R(m)C 3'. DNA cleavage normally requires translocation-mediated coordination between two such recognition elements at distinct sites. We have investigated assembly of the cleavage-competent complex with gel-shift and DNase I footprint analysis. In the gel-shift system, McrB(L) binding resulted in a fast-migrating specific shifted band, in a manner requiring both GTP and Mg(2+). The binding was specific for methylated DNA and responded to local sequence changes in the same way that cleavage does. Single-stranded DNA competed for McrB(L)-binding in a modification and sequence-specific fashion. A supershifted species was formed in the presence of McrC and GTPgammaS. DNase I footprint analysis showed modest cooperativity in binding to two sites, and a two-site substrate displayed protection in non-specific spacer DNA in addition to the recognition elements. The addition of McrC did not affect the footprint obtained. We propose that McrC effects a conformational change in the complex rather than a reorganization of the DNA:protein interface.

5-Methylcytosine↗

A simple in vitro Tn7-based transposition system with low target site selectivity for genome and gene analysis.

A robust Tn7-based in vitro transposition system is described that displays little target site selectivity, allowing the efficient recovery of many different transposon insertions in target DNAs ranging from small plasmids to cosmids to whole genomes. Two miniTn7 derivatives are described that are useful for the analysis of genes: one a derivative for making translational and transcriptional target gene fusions and the other a derivative that can generate 15 bp (5 amino acid) insertions in target DNAs (proteins).

Amino Acid Sequence↗

Plantar lipomatosis, unusual facial phenotype and developmental delay: a new MCA/MR syndrome.

We describe two boys with global developmental delay and a phenotype of microcephaly, midface hypoplasia, enlarged fleshy ears, depressed nasal bridge, anteverted nostrils, central palatal ridge, and high forehead. Bilateral congenital fat pads are present anteromedial to the heels. Fetal finger and toe pads are present and palmar and plantar grooves are deeper than normal with "pillowing" of the areas between the grooves. No patients with similar clinical findings have been located, but these two children have a remarkably similar clinical presentation which we consider a "new" syndrome.

Child↗

Early amniocentesis: effect of removing a reduced volume of amniotic fluid on pregnancy outcome.

In mid-trimester amniocentesis (MTA), 12-15 ml of amniotic fluid is aspirated for cytogenetic analysis. When a similar volume of amniotic fluid is removed by early amniocentesis (EA), it represents a significant proportion of the total amniotic fluid volume in the first trimester. The fluid depletion, which may persist for 7 to 10 days, is considered to impair development of fetal lungs and extremities and, possibly, contribute towards procedure-related congenital abnormalities and miscarriages. By only removing 7 ml of amniotic fluid, we have demonstrated a total miscarriage rate (3.8 per cent) comparable with previous large studies (Table V), a low incidence of respiratory difficulties at birth (2.7 per cent) and a low incidence of fixed flexion deformities (1.6 per cent), at the expense of a small increase in the incidence of culture failure (2.2 per cent).

Abortion, Spontaneous↗

Rural and urban female secondary school students' attitudes towards and use of primary care services.

In light of the current and ongoing threats to young women's health of unplanned pregnancy and sexually transmissible diseases (including HIV/AIDS), assured access to appropriate and sensitive health services is of paramount importance. In this article, the results of a recent Victorian study involving rural and urban female secondary school students on issues relating to sexual health are reported. Drawing upon the findings of an extensive self-report questionnaire, young women's attitudes towards and use of health services are presented with a particular focus upon the variations that exist between the rural and urban populations. Apart from issues associated with privacy, which were found to be more crucial to rural young women's decisions to seek medical care, this study found young women's concern about the attitudes of medical and non-medical staff alike, the atmosphere of surgery or clinic, and gender of doctor all to be important factors in their general use of health services, regardless of location.

Adolescent↗

Wolcott-Rallison syndrome associated with congenital malformations and a mosaic deletion 15q 11-12.

Wolcott-Rallison syndrome is a rare autosomal recessive condition first described in 1972. It is characterised by diabetes mellitus which arises in early infancy and multiple epiphyseal dysplasia. We describe an affected girl who had recurrent episodes of hepatic failure for which no obvious cause was found. Post-mortem examination revealed abnormal pancreatic histology and congenital abnormalities of the central nervous and cardio-respiratory systems which have not been previously described in this condition. She also demonstrated a deletion at 15q 11-12 in 65% of her cells.

Abnormalities, Multiple↗

An autosomal dominant syndrome of acromegaloid facial appearance and generalised hypertrichosis terminalis.

We report a family in which a phenotype of acromegaloid facial appearance (AFA) and generalised hypertrichosis terminalis segregates through three generations. Congenital hypertrichosis terminalis and AFA have been previously reported as independent autosomal dominant traits. This is the first report to delineate an autosomal dominant transmission of the combined phenotype.

Acromegaly↗

Non-phenylketonuria hyperphenylalaninaemia in Northern Ireland: frequent mutation allows screening and early diagnosis.

Up to 10% of newborn children with a positive Guthrie test have non-phenylketonuria hyperphenylalaninaemia, i.e., mild elevation of serum phenylalanine that does not require dietary treatment. Depending on the relative frequencies of different phenylalanine hydroxylase mutations in a particular population, non-PKU HPA is usually caused by the combined effect of a mild HPA mutation and a severe PKU mutation. Presented here is a comprehensive analysis of non-PKU HPA in Northern Ireland. Of particular interest is one prevalent HPA mutation (T380M), which is present in over 70% of non-PKU HPA patients in Northern Ireland. Screening for this mutation is easy and inexpensive and can help confirm the diagnosis of non-PKU hyperphenylalaninaemia in the majority of cases at a very early stage. This may be clinically useful and reassuring for the parents. Other mutations described are V245A, L194P, and E390G.

Adolescent↗

Microcephaly with large anterior fontanelle, generalized convulsions, micropenis, and distinct anomalies of the hands and feet. Another example of Wiedemann syndrome?

Wiedemann et al. (1985) described a rare syndrome characterised by microcephaly, psychomotor delay, short stature, short fingers and toes with stubby broad thumbs and halluces. Unilateral undescended testis, inguinal hernias, scrotal hypoplasia, and micropenis were also features. They described two males, first cousins, whose mothers and maternal grandfather had short broad thumbs and halluces. We report a male with identical features whose parents were normal. This is only the second report of this syndrome. Autosomal or X-linked dominant inheritance is most likely.

Abnormalities, Multiple↗

Automated sequencing detects all mutations in Northern Irish patients with phenylketonuria and mild hyperphenylalaninaemia.

In the first phase of the Northern Ireland PKU Study, we used automated sequencing to identify the spectrum of mutations in a random group of 32 unrelated phenylketonuria (PKU) families. We also investigated 7 Northern Irish patients with mild hyperphenylalaninaemia not requiring dietary intervention (MHP, previously referred to as non-PKU HPA). Disease-causing mutations were identified on all 78 investigated chromosomes. We found 23 different mutations, including 20 missense, 1 nonsense and 2 splice site mutations. All mutations were located within exons or at intron-exon boundaries of the phenylalanine hydroxylase gene. Seven mutations occurred at CpG sites, confirming these sites as mutation hot-spots in PKU. Mutations R408W and I65T are the two commonest PKU mutations in the Northern Irish population. Two mutations (T380M and V245A) can be characterized as MHP mutations; they are quasi dominant markers for MHP since they cause mild hyperphenylalaninaemia even when occurring in conjunction with the most severe PKU mutations. The results have proven valuable for the development of a routine PKU mutation analysis system in Northern Ireland.

DNA Mutational Analysis↗

Axial mesodermal dysplasia spectrum.

We report on a 4-month-old boy with manifestations of both the oculo-auriculovertebral spectrum and the caudal regression sequence. He has preauricular appendages, thoracic and lumbar hemivertebrae, anomalies of the ribs, dextrocardia, sacral "dysplasia," dislocated hips, bilateral talipes equinovarus, imperforate anus, recto-vesical fistula, malformed scrotum, and undescended testes. As suggested by Russell et al. [1981], who reported a patient with similar anomalies, the spectrum of anomalies probably is due to a generalized alteration in mesodermal cell migration during the primitive streak period. The term "axial mesodermal dysplasia spectrum" best describes the widespread anomalies in the cranial and caudal regions.

Abnormalities, Multiple↗