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Biomedical subjects

J G Rogers

Publications and source records attributed to J G Rogers.

At least 19 recordsLinked to original sources
PubMed1996

Anaesthesia for children with mucopolysaccharidoses.

The mucopolysaccharidoses are a group of inherited disorders of metabolism, with varying clinical manifestations. A number of them present anaesthetic difficulties. This paper presents a summary table of the syndromes and reviews our experience over ten years with patients with these diagnoses. The clinical presentations, anaesthetic management, and complications are described. The effect of age and diagnosis on airway difficulties was studied. There were 31 patients, 28 of whom required anaesthesia, on a total of 99 occasions, for 115 procedures. The patients with Hunter, Hurler and Maroteaux-Lamy syndromes had significantly more airway difficulties as they grew older, and compared with patients in this group with other syndromes. Patients with Hurler's syndrome may have coronary artery involvement and one patient was given fentanyl and pancuronium for this reason. He proved impossible to intubate and an emergency tracheostomy was performed.

Adolescent↗
PubMed1995

Type X collagen multimer assembly in vitro is prevented by a Gly618 to Val mutation in the alpha 1(X) NC1 domain resulting in Schmid metaphyseal chondrodysplasia.

Type X collagen is a homotrimer of alpha 1(X) chains encoded by the COL10A1 gene. It is a highly specialized extracellular matrix component, and its synthesis is restricted to hypertrophic chondrocytes in the calcifying cartilage of the growth plate and in zones of secondary ossification. Our studies on a family with Schmid metaphyseal chondrodysplasia demonstrated that the affected individuals were heterozygous for a single base substitution in the COL10A1 gene, which changed the codon GGC for glycine 618 to GTC for valine in the highly conserved region of the carboxyl-terminal NC1 domain and altered the amino acid sequence in the putative oligosaccharide attachment site. Since hypertrophic cartilage tissues or cell cultures were not available to assess the effect of the mutation, an in vitro cDNA expression system was used to study normal and mutant type X collagen biosynthesis and assembly. Full-length cDNA constructs of the normal type X collagen sequence and also cDNA containing the specific Gly to Val NC1 mutation found in the patient were produced and expressed by in vitro transcription and translation. While the control construct produced type X collagen, which formed trimeric collagen monomers and assembled into larger multimeric assemblies, the mutant collagen was unable to form these larger aggregates. These experiments demonstrated that the mutation disturbed type X collagen NC1 domain interaction and assembly, a finding consistent with the abnormal disorganized cartilage growth plate seen in the patient. These studies provide the first evidence of the effect of a type X collagen mutation on protein structure and function and directly demonstrate the critical role of interactions between NC1 domains in the formation of type X collagen multimeric structures in vitro.

Amino Acid Sequence↗
PubMed1995

Severe intrauterine growth retardation with increased mitomycin C sensitivity: a further chromosome breakage syndrome.

We report an infant with pre- and postnatal microcephaly and growth retardation, a distinctive face, and developmental delay. The initial diagnosis was of Seckel syndrome. He became pancytopenic at 16 months and died soon after. His bone marrow was of normal cellularity but had a small lymphocyte infiltration. Increased spontaneous chromosome breakage was seen in blood and fibroblasts. Mitomycin C induced chromosome damage was increased and comparable to that seen in Fanconi anaemia. Reports of similar patients are reviewed. This entity of severe intrauterine growth retardation and increased mitomycin C sensitivity is hypothesised to be a distinct chromosome breakage syndrome.

Adult↗
PubMed1994

Osteomesopycnosis.

The radiographic findings in two children with osteomesopycnosis are described. This is the first report in the Australian literature of this uncommon, recently described entity.

Adolescent↗
PubMed1994

Two sibs who are double heterozygotes for achondroplasia and pseudoachondroplastic dysplasia.

We report a family in which two sibs have both achondroplasia and pseudoachondroplastic dysplasia. The mother has achondroplasia and the father has pseudoachondroplastic dysplasia, which he had inherited from his father. Both children appeared typical of achondroplasia at birth. By 1 1/2 years they had developed a fixed lumbar kyphosis with gibbus and had additional x ray changes unusual for just achondroplasia and suggestive of pseudoachondroplastic dysplasia. Subsequently both children have shown characteristic features of both conditions and have grown less well than expected for achondroplasia. Radiographs show the striking synergistic effects of the two conditions. MRI in both sibs confirmed brain stem compression at the foramen magnum. This may be an important complication and should be actively sought in any double heterozygote.

Achondroplasia↗
PubMed1993

The clinical features of spondyloepiphyseal dysplasia congenita resulting from the substitution of glycine 997 by serine in the alpha 1(II) chain of type II collagen.

The features of a child with spondyloepiphyseal dysplasia congenita resulting from a mutation in one COL2A1 allele were studied. The child was heterozygous for a G to A transition in exon 48 that resulted in the substitution of glycine 997 by serine in the triple helical domain of alpha 1(II) chains of type II collagen. Her longitudinal growth was close to the mean growth curve for children with this chondrodysplasia. Expression of the mutation by chondrocytes would account for the abnormal growth and development of the bones of the limbs and spine. Early expression of the mutation by epithelial cells and later expression by chondrocytes of the developing craniofacial structures would also account for her complex pattern of craniofacial anomalies. The findings in this study confirm that mutations of exon 48 of the COL2A1 gene, that alter the normal Gly-X-Y triplet structure of the corresponding region of alpha 1(II) chains of type II collagen, produce the spondyloepiphyseal dysplasia congenita phenotype.

Collagen↗
PubMed1993

Perinatal education for women with physical disabilities.

Pregnant women with disabilities have many of the same concerns as able-bodied pregnant women. However, pregnant women with disabilities have special perinatal education needs. Information on the problems encountered and approaches that can be used is presented based on current research and interviews with 36 childbearing women with disabilities.

Breathing Exercises↗
PubMed1992

X-linked pyruvate dehydrogenase E1 alpha subunit deficiency in heterozygous females: variable manifestation of the same mutation.

Three female patients are described with pyruvate dehydrogenase (PDH) deficiency as a result of mutation in the X-linked gene for the E1 alpha subunit of the complex. Two of these patients illustrate typical presentations of PDH E1 alpha deficiency, with severe neurological dysfunction, degenerative changes and developmental anomalies in the brain, together with variable lactic acidosis. The third patient extends the known spectrum of the condition to include mild to moderate mental retardation and seizures in an adult. All three patients have the same mutation in the PDH E1 alpha gene. This mutation, a C-to-T substitution in a CpG dinucleotide in amino acid codon 302 (designated R302C), results in the replacement of arginine by cysteine at this position. The mildly affected adult was the mother of one of the other patient, making this the first described instance of mother-to-daughter transmission of a mutation causing PDH E1 alpha deficiency. The genetic basis of the variable expression of X-linked PDH E1 alpha deficiency in heterozygous females is discussed.

Adolescent↗
PubMed1992

Full data utilization in PVI using the 3D radon transform.

An algorithm is described for three-dimensional (3D) image reconstruction in positron volume imaging (PVI) using the inversion of the 3D radon transform (RT) for a truncated cylindrical detector geometry. A discrete version of the 3D RT is formed in a 3D histogram from the event-line coordinates of the detected events. The histogram entries represent the plane integrals of the activity in the field of view. Conventional inversion of the x-ray transform (XT) excludes oblique events in non-iterative reconstruction methods. by employing a spatially varying angular acceptance of events into the histogrammed plane integrals of the 3D RT, it is possible to include most of the detected oblique events in the reconstruction of the image using the standard 3D RT inversion formula. the oblique events are added to the histogram with a partial weight compared to those in complete (XT) projections. This single-pass reconstruction image has better statistical noise properties than images formed by RT inversion from complete XT projections, but only for some detector geometries is it significantly better. Monte Carlo simulations were used to study the statistical noise in images reconstructed using the new algorithm. The inherent difference in the axial versus the transaxial statistical noise in images reconstructed from truncated detectors is noted and is found to increase by including oblique events with this new algorithm.

Algorithms↗
PubMed1991

Williams syndrome in one dizygotic twin.

Williams syndrome is a disorder of unknown etiology with a characteristic facial appearance, vascular disease and infantile hypercalcemia. Most cases are sporadic. We report the case of a dizygotic male twin with the Williams syndrome. This appears to be the first report of twins with only one affected. This suggests a mutational event as the cause of Williams syndrome.

Aortic Valve Stenosis↗
PubMed1990

Autosomal recessive hydrocephalus with third ventricle obstruction.

Here we report a brother and sister who presented in the neonatal period with hydrocephalus. Ultrasonography showed marked dilatation of the lateral ventricles but not the third ventricle. One child with postnatal onset was shunted and had normal development at 3 years. The other child had severe hydrocephalus at birth and was not treated. Neuropathologic studies demonstrated dilatation of the lateral ventricles and marked narrowing of the posterior part of the third ventricle but no other malformations other than those that result directly from hydrocephalus. The potential for a good prognosis is emphasized.

Cerebral Ventricles↗
PubMed1990

Marfan syndrome: absence of type I or III collagen structural defects in 25 patients.

The structure and metabolism of type I and III collagens were studied in fibroblast cultures and dermis from 25 unrelated patients including 23 with typical Marfan syndrome and two infants with a very severe clinical form of this syndrome. Electrophoretic analysis of collagen alpha-chains, as well as one- and two-dimensional electrophoresis of collagen cyanogen bromide peptides, failed to show any evidence of primary structure defects or overmodification of lysine residues in these collagens. The proportion of hydroxylated prolyl residues in isolated alpha 1(I) chains was also normal. There was a minimal increase in the proportion of type III collagen produced by nine cultures. The findings in this study indicate that the underlying molecular defects in the patients studied are unlikely to involve the structure of the main fibrillar type I and III collagens.

Cells, Cultured↗
PubMed1990

Five cases demonstrating the distinctive behavioural features of chromosome deletion 17(p11.2 p11.2) (Smith-Magenis syndrome).

Children with hyperactivity and self-destructive behaviour present a difficult problem for parents and paediatricians. The syndrome described by Smith and Magenis is due to a deletion on the short arm of chromosome 17: del(17)(p11.2 p11.2). Clinical manifestations include brachycephaly and a flat mid-face; brachydactyly; short, broad hands; mental retardation; and aberrant behaviour, including hyperactivity. We report on five children, and review the literature on a newly recognised syndrome in which the behaviour manifestations may precede and often overshadow the learning disabilities and unusual appearance. In addition, we have found sleep disturbance to be a major feature in our patients.

Child↗
PubMed1990

The clinical features of three babies with osteogenesis imperfecta resulting from the substitution of glycine by arginine in the pro alpha 1(I) chain of type I procollagen.

The features of three babies with lethal perinatal osteogenesis imperfecta resulting from the substitution of glycine by arginine in the pro alpha 1(I) chain of type I procollagen were studied. The babies were heterozygous for this substitution at residue 391 in case 1 (0I24), 667 in case 2 (0I51), and 976 in case 3 (0I30). They were all small, term babies who died soon after birth. The ribs were broad and continuously beaded in 0I24, discontinuously beaded in 0I51, and slender with few fractures in 0I30. The overall radiographical classifications were type IIA in 0I24, IIA/IIB in 0I51, and IIB in 0I30. Histological examination confirmed that the long bones were misshapen and porotic. The calcified cartilage trabeculae were covered with an abnormally thin layer of osteoid and the bone trabeculae were thin and basophilic. There was no evidence of lamellar bone or Haversian systems. The osteoblasts remained relatively large and closely spaced. These babies shared many phenotypic features, but differences in the radiographical appearance of the ribs and long bones suggested that there was a gradient of bone modelling capacity from the slender and overmodelled bones in 0I30 to the absence of modelling in 0I24.

Female↗
PubMed1990

The clinical features of osteogenesis imperfecta resulting from a non-functional carboxy terminal pro alpha 1(I) propeptide of type I procollagen and a severe deficiency of normal type I collagen in tissues.

The features of a baby with lethal perinatal osteogenesis imperfecta (OI II), owing to a frameshift mutation that resulted in the production of a truncated and functionless carboxy terminal propeptide of the pro alpha 1(I) chain of type I procollagen, were studied. The baby (OI26) was heterozygous for an insertion of a single uridine nucleotide after base pair 4088 of the prepro alpha 1(I) mRNA of type I procollagen. Only normal type I collagen was incorporated into the extracellular matrix of bone and dermis resulting in a type I collagen content of about 20% of control tissues. The baby was born at 35 weeks' gestation and died shortly afterwards. He was small and had the radiographical features most like those of OI IIB. The skeleton was poorly ossified. The ribs were discontinuously beaded and the femora were broad with multiple healed fractures of the diaphyses and metaphyses. Other long bones had broad metaphyses with overmodelled diaphyses. The calvarium contained many hundreds of wormian bones. Histological examination showed grossly deficient endochondral and intramembranous ossification. The bone was of a woven type without evidence of lamellar bone or Haversian systems and the osteoblasts did not mature into osteocytes. The cortex of the femur contained Haversian canals but they were surrounded by loose collagen fibres and a mosaic pattern of woven bone and islands of cartilage. We propose that OI IIB can be sub-classified into two groups, one with helical mutations and both normal and mutant type I collagen in the tissues, and the other with carboxy terminal propeptide mutations and a severe type I collagen deficiency, but without mutant collagen in the tissues.

Bone and Bones↗
PubMed1990

Development of the hip in multiple epiphyseal dysplasia. Natural history and susceptibility to premature osteoarthritis.

We have determined the natural history of hip development in 42 patients with multiple epiphyseal dysplasia (MED). Premature osteoarthritis was a frequent outcome and was almost inevitable before the age of 30 years in those with incongruent hips. There were two types of immature hips: type I, the more severe form, had a fragmented and flattened ossific nucleus and acetabular dysplasia, was misshapen at skeletal maturity and osteoarthritic by 30 years of age; the milder type II hip had a small, rounded, uniformly ossified nucleus and a more normal acetabulum. Type II hips were well formed at maturity and were less prone to premature osteoarthritis. Considerable variations were noted in the manifestations of MED between families but not within families. The prognosis of a child's hip could be predicted; in sporadic cases from the type of immature hip, and in familial cases by also taking into account the outcome of affected relatives.

Adult↗