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Biomedical subjects

J Masel

Publications and source records attributed to J Masel.

At least 19 recordsLinked to original sources
PubMed2000

Clinical findings in a patient with FGFR1 P252R mutation and comparison with the literature.

We report on a patient with the skeletal findings of Jackson-Weiss syndrome, who manifests only mild craniofacial anomalies. Molecular analysis of her fibroblast growth factor receptor 1 gene (FGFR1) identified a heterozygous P252R missense mutation, previously only reported with FGFR1-Pfeiffer syndrome like manifestations. Mutations in the immunoglobulin-like, II-III (IgII-III) linker region of FGFR1 and FGFR3 molecules may present as a skeletal dysplasia affecting the appendicular skeleton including, brachydactyly, short broad middle phalanges, phalangeal epiphyseal coning and broad halluces. This communication is a further example of the phenomenon of an activated FGFR molecule resulting in overlapping manifestations in FGFR syndromes.

Abnormalities, Multiple↗
PubMed2000

Fluctuations in HIV-1 viral load are correlated to CD4+ T-lymphocyte count during the natural course of infection.

Viral load fluctuates during the natural course of asymptomatic HIV-1 infection. It is often assumed that these fluctuations are random around a set point or underlying growth trend. Using longitudinal data, we tested whether fluctuations in viral load can be better explained by changes in CD4+ T-cell count than by a set point or trend of exponential growth. The correspondence between viral load and CD4+ T-cell count could be described by a simple mathematical relation. Using a bootstrapping approach, the hypothesis that viral load fluctuations are random around a set point was rejected with p < .00005. The hypothesis that viral load fluctuations are random around a trend of exponential growth was rejected with p < .005. Viral load data was explained better by changes in CD4+ T-cell counts than by a set point or by a trend of exponential growth. The implications of this finding for improved prognostication are discussed.

CD4 Lymphocyte Count↗
PubMed2000

Evaluation and management of mechanical dysfunction in continent colonic urinary reservoirs.

PURPOSE: We analyze a group of patients who presented with mechanical dysfunction of the reservoir and/or efferent limb of a continent colonic urinary diversion, and establish an evaluation and management algorithm. MATERIALS AND METHODS: A total of 16 patients with a mean age of 58 years and 1 or more symptoms related to continent colonic urinary diversion were evaluated. Presenting symptomatology included difficult catheterization in 8 cases (50%), disabling incontinence in 8 (50%) and recurrent urinary tract infections in 6 (37.5%). All patients had normal, nonobstructed, nonrefluxing upper tracts and none presented with stone disease. Urological evaluation consisted of catheterization, fluoroscopy and urography of the pouch, retrograde urography of the external limb and urodynamics (enterocystometrogram and outlet pressure profilometry). RESULTS: Of the 8 patients with difficulty with catheterization 4 had stomal stenosis, 2 had an elongated and redundant external limb, and 2 had a false passage. Diagnosis was established by the inability to catheterize, fluoroscopy of the pouch and retrograde urography. Disabling incontinence occurred in 8 patients, including 7 who presented with an incompetent outlet and 2 with high pressure intestinal contractions of the reservoir. The aforementioned abnormalities were diagnosed by a combination of retrograde urography, urography of the pouch and urodynamics. Recurrent symptomatic urinary infections were observed in 5 patients of the previous groups and in another with an hourglass reservoir, which was primarily diagnosed by urography of the pouch. Surgical correction in 15 patients included outlet reinforcement, reservoir revision, stomal or external limb revision and conversion to a urinary conduit. Surgical treatment was successful in 14 of 15 patients (93%). CONCLUSIONS: Catheterization difficulty requires retrograde urography to define possible anatomical abnormalities (false passage, conduit elongation) if catheterization and fluoroscopy of the pouch do not demonstrate stomal stenosis. Urinary incontinence benefits from enterocystometry and outlet pressure measurement to determine reservoir and external limb function. Recurrent urinary tract infections not related to ureteral obstruction or reflux requires fluoroscopy of the pouch and external limb to determine abnormalities in patients with detubularization and localization of areas of urine pooling.

Adult↗
PubMed1999

The kinetics of proteinase K digestion of linear prion polymers.

Transmissible spongiform encephalopathies such as scrapie are caused by a protein-only infectious agent, known as a prion. It is not clear how a protein can be capable of replicating itself, and the mechanism remains controversial. One influential model hypothesizes that prions are nucleated, macroscopically linear polymers. We investigated the theoretical kinetics of this model and derived predictions which could be used to test the model. In the model, the polymerization and depolymerization rates are independent polymer size. This leads to an exponential size distribution at equilibrium. In agreement with a prediction stemming from this size distribution, the average size of PrP-res polymers was proportional to the square root of the concentration of PrP-res in a published study of in vitro conversion. Prion digestion by proteinase K (PK) is predicted to be biphasic. The second phase of digestion should be virtually independent of the PK concentration and should depend on the initial size distribution of prion polymers. For initially equilibrated polymers with an exponential size distribution, phase two digestion is exponential at a predicted rate. This rate varies in a defined way with the concentration used for equilibration and with other parameters which affect the average polymer size.

Biopolymers↗
PubMed1999

Quantifying the kinetic parameters of prion replication.

The mechanism of protein-only prion replication is controversial. A detailed mathematical model of prion replication by nucleated polymerisation is developed, and its parameters are estimated from published data. PrP-res decay is around two orders of magnitude slower than PrP-sen decay, a plausible ratio of two parameters estimated from very different experiments. By varying the polymer breakage rate, we reveal that systems of short polymers grow the fastest. Drugs which break polymers could therefore accelerate disease progression. Growth in PrP-res seems slower than growth in infectious titre. This can be explained either by a novel hypothesis concerning inoculum clearance from a newly infected brain, or by the faster growth of compartments containing smaller polymers. The existence of compartments can also explain why prion growth sometimes reaches a plateau. Published kinetic data are all compatible with our mathematical model, so the nucleated polymerisation hypothesis cannot be ruled out on dynamic grounds.

Animals↗
PubMed1999

Variability in kyphomelic dysplasia.

Four infants with kyphomelic dysplasia ascertained from three families demonstrate variability within the syndrome. In the first family, sibling recurrence in female sibs was noted with atypical kyphomelic dysplasias, suggesting autosomal recessive inheritance. In the second family, with a male affected with the 'typical findings' of lethal kyphomelic dysplasia, diagnosis of a skeletal dysplasia was suspected at 29-30 weeks' gestation following US detection of short, bent femurs. In the third family, with a female affected, severe radiographic changes were documented at birth. The clinical course of the disease was mild with almost complete regression of the radiographic findings at the age of 7 years.

Abortion, Induced↗
PubMed1999

Mesomelic dysplasia with periosteal thickening, radio-humeral dislocation, osteoporosis and multiple fractures.

UNLABELLED: We report a boy with a new form of mesomelic dysplasia characterised by short stature, multifocal periosteal thickening, radio-humeral dislocation, osteoporosis and multiple fractures with minimal trauma. Electrophoresis of fibroblast collagens detected defects in type III and type V collagen. CONCLUSION: Bone dysplasias presenting with osteopenia, abnormal trabecular pattern, bone fragility, and periosteal thickening suggest a collagenopathy. A possible collagen defect requires biochemical investigations.

Abnormalities, Multiple↗
PubMed1999

Antenatal detection and management of suprarenal masses.

The indications for, and timing of, surgical intervention for suprarenal masses detected prenatally are unclear. Also, the definitive diagnosis of suprarenal masses using imaging studies is difficult at best. We report 2 cases of antenatally detected suprarenal masses. One case represents an initial cystic mass expanding and becoming solid that had benign pathologic features. The second case was a stable solid mass that, on exploration, was malignant. Management options are discussed.

Adrenal Gland Diseases↗
PubMed1999

Feeding problems in infants with gastro-oesophageal reflux disease: a controlled study.

OBJECTIVE: Gastro-oesophageal reflux disease (GORD) in infants is commonly associated with feeding problems but has not been subject to systematic controlled study. We evaluated feeding, dietary, behavioural data obtained from systematic objective studies of six-month old infants with and without GORD. METHODS: Infants with GORD (defined by 24-h pH monitoring, n = 20), and age, gender, gestation, and socio-economic matched healthy infants (n = 20) had standardised assessments of dietary intake, oromotor function by videoanalysis (Feeding Assessment Schedule, FAS), and infant feeding behaviour by Testers and Maternal Ratings (TRIB and MRIB). Videofluoroscopic analyses of swallowing was undertaken in 11/20 GORD infants and analysed by standardised paediatric check list. RESULTS: Compared with control data: GORD infants had significantly lower energy intakes; the FAS showed GORD infants to have significantly fewer adaptive skills and readiness behaviour for solids, significantly more food refusal and food loss; the TRIB showed GORD infants to be significantly more demanding and difficult with feeds; and the MRIB revealed that mothers of GORD infants had significantly more negative feelings, significantly less enjoyment of feeds, and reported significantly more crying behaviour. On videofluoroscopy, oral-preparatory and oral phase problems predominated, particularly with solids, silent aspiration occurred during the pharyngeal phase in 2/11, and delayed oesophageal transit occurred in 4/11. CONCLUSIONS: Feeding problems affecting behaviour, swallowing, food intake, and mother-child interaction occur in infants with GORD, who displayed a lack of development of age-appropriate feeding skills. The contribution of feeding problems to morbidity in GORD in infants has been underestimated in the past.

Bottle Feeding↗
PubMed1997

Measurement of radiation dose received by the hands and thyroid of staff performing gridless fluoroscopic procedures in children.

The aim of this study was to confirm that the radiation doses received by attendants who manually restrain infants during fluoroscopic procedures are low. Doses to the hands and neck of three radiologists and three nurses performing or assisting at all the fluoroscopic procedures in a children's hospital were measured for 1 month using thermoluminescent dosemeters. All fluoroscopy on children at this hospital is performed without an antiscatter grid. Total doses for the neck ranged from 20 to 50 microSv per week and for hands from 40 to 210 microSv per week. These doses were shared by the three radiologists and the three nurses. Individual doses received per staff member are very small when compared with the doses received by interventional radiology staff. Doses received by staff in this study were of the order of 5% of the limit advised by the National Health and Medical Research Council of Australia (NHMRC) for radiation workers. Nurses received larger doses than radiologists and steps will be taken to reduce this dose further.

Adolescent↗
PubMed1996

Dysosteosclerosis.

A 5 1/2 year old boy presented with delayed development and loss of vision. A skeletal survey showed osteosclerosis consistent with dysosteosclerosis. Some unusual features of dysosteosclerosis are discussed.

Bone and Bones↗
PubMed1996

Coexistent orbital and cerebellar venous anomalies in linear sebaceous naevus syndrome.

BACKGROUND: Orbital venous anomalies can result in significant morbidity and have been reported in association with other venous anomalies, some with the potential for serious complication. METHODS/RESULTS: We present a case of an orbital venous anomaly coexistent with a large cerebellar venous angioma and a linear sebaceous naevus. Clinical features, associations, complications and management principles are presented. CONCLUSION: Upon clinical recognition of an orbital venous anomaly, brain imaging and appropriate clinical assessment should be considered in light of the possibility of coexistence of potentially life-threatening lesions.

Brain Neoplasms↗
PubMed1995

Case report: neonatal platyspondylic dwarfism--a new form.

A new type of neonatal bone dysplasia is reported. Unusual radiographic abnormalities (platyspondyly with unique shape of the vertebral bodies, shortening of the long tubular bones without signs of rickets or metaphyseal dysplasia, marked shortening of well-ossified short tubular bones, schneckenbecken-like pelvis with tri-radiate acetabulum, pseudoepiphysis of the right ulna, unusual shape of calcaneus and periarticular calcifications) allow designation of this disorder as a new form of neonatal dwarfism.

Abnormalities, Multiple↗
PubMed1993

Microcephalic, osteodysplastic, primordial dwarfism.

A case of microcephalic, osteodysplastic, primordial dwarfism (cephaloskeletal dysplasia of Taybi and Linder) is reported. This rare disease is characterised by unique clinical appearances and diagnostic radiographic findings. It is also associated with distinctive brain abnormalities. The latter include micrencephaly, lissencephaly, corpus callosum aplasia/agenesis and unusual histological brain abnormalities.

Abnormalities, Multiple↗
PubMed1992

Cystic encephalomalacia and intrauterine herpes simplex virus infection.

Cystic encephalomalacia occurred in two preterm infants who had proven intrauterine herpes simplex virus type 2 infection. Calcification was evident in the basal ganglia. Follow-up scans indicated that the cysts had resolved over a period of two months in one infant, while in the case of the other, the cysts became progressively larger with significant ventricular dilatation developing. While cystic changes in the brain of preterm infants are usually due to periventricular leukomalacia, intrauterine infection needs to be considered as a possible cause. Antiviral treatment may be of benefit to infants with herpes simplex virus infection.

Brain Diseases↗
PubMed1991

Rare primary cranial vault and base of the skull tumors in children. Report of 30 cases with a short literature review.

Twenty-six cases of rare primary cranial vault tumors are reported, together with 4 cases of primary tumors of the base of the skull and 3 cases of monostotic cranial neuroblastoma. Whereas some rare primary cranial vault tumors may present with characteristic radiographic patterns (e.g. hemangioma, aneurysmal bone cyst, osteoma, progonoma), most of them can be recognised only after histology. The most frequent tumor in the region of previous irradiation is osteosarcoma. The only "common" primary bone tumor of the base of the skull is chordoma. The radiological differential diagnosis of primary tumors of the skull vault and base is discussed.

Adolescent↗
PubMed1990

Primary sacral bone tumours in children (report of 16 cases with a short literature review).

16 cases of primary sacral bone tumours in children are reported. These include 13 patients with Ewing's sarcoma and 3 with very rare primary sacral bone tumours in childhood--chordoma, haemangiopericytoma and osteoblastoma. All sacral bone tumours, with the exception of Ewing's sarcoma are very rare in childhood. The possibility of a sacral tumour should be considered in a child with radiculopathy. CT and MR make the diagnosis of primary sacral bone tumours much easier with the added possibility of recognition of the true nature of the lesion in many instances. Reports of primary sacral bone tumours in children are scarce. Most of the patients are incorporated in adult series which do not specify the age of the child and the site of the tumour. The purpose of this paper is to describe 16 children with primary sacral bone tumours.

Child↗