Search PubMed⌕ Search

Biomedical subjects

J C Dean

Publications and source records attributed to J C Dean.

At least 37 records · Page 2Linked to original sources
PubMed1998

Mosaicism for a tandem duplication dup(1)(q12q22) in an 18 year old female.

The clinical features and cytogenetic results of an 18 year old mentally handicapped female found to be a mosaic for a tandem duplication of chromosome 1 (46,XX,dup(1)(q12q22)/46,XX) are reported. The case is compared with the three previously described cases and possible mechanisms for the origin of the duplication are discussed. This patient was not found to have features of Proteus syndrome which was previously reported in a subject mosaic for a tandem duplication involving chromosome (1)(q11q25).

Adolescent↗
PubMed1998

The nominating committee.

The nominating committee is vitally important because it identifies, prioritizes, recruits, and orients new members, and retains existing, strong leadership within the organization's guidelines, constitution and by-laws. It is the most important committee because it recruits board leadership, and leadership is the essential ingredient for success.

Charities↗
PubMed1997

Mulvihill-Smith progeria-like syndrome: a further report with delineation of phenotype, immunologic deficits, and novel observation of fibroblast abnormalities.

We report the seventh case of Mulvihill-Smith progeria-like syndrome in a 5-year-old boy with a thin, pinched face, failure to thrive, and cutaneous pigmented nevi. The patient's motor and intellectual development were normal. His immune function tests demonstrate evidence of lymphopenia with no selective loss of a major subpopulation, low immunoglobulin (Ig)G2 and IgG4 subclasses, and an absent in vitro proliferative response to pokeweed mitogen. Chromosomal mitomycin and radiation sensitivity were normal. The skin fibroblast growth in culture was slow, and the fibroblasts appeared morphologically different from normal controls in their size and large number of inclusions. In addition, primary cilia, which normally issue from the centrosome, were absent-a new finding in fibroblasts in this disorder. It remains to be seen if the relative absence of centrosomal cilia in cultured fibroblasts in early passages is a consistent finding in this progeria syndrome.

Abnormalities, Multiple↗
PubMed1997

Craniosynostosis associated with FGFR3 pro250arg mutation results in a range of clinical presentations including unisutural sporadic craniosynostosis.

Several mutations involving the fibroblast growth factor receptor (FGFR) gene family have been identified in association with phenotypically distinct forms of craniosynostosis. One such point mutation, resulting in the substitution of proline by arginine in a critical region of the linker region between the first and second immunoglobulin-like domains, is associated with highly specific phenotypic consequences in that mutation at this point in FGFR1 results in Pfeiffer syndrome and analogous mutation in FGFR2 results in Apert syndrome. We now show that a much more variable clinical presentation accompanies analogous mutation in the FGFR3 gene. Specifically, mental retardation, apparently unrelated to the management of the craniosynostosis, appears to be a variable clinical consequence of this FGFR3 mutation.

Acrocephalosyndactylia↗
PubMed1996

Cranial desmoid tumor associated with homozygous inactivation of the adenomatous polyposis coli gene in a 2-year-old girl with familial adenomatous polyposis.

BACKGROUND: Familial adenomatous polyposis (FAP) is a dominantly inherited disorder characterized by the presence of more than 100 adenomatous polyps in the colon and rectum starting in the second decade of life. FAP is associated with extra colonic manifestations, including desmoid tumors. METHODS: A 2-year-old girl presented with a rapidly enlarging tumor of the forehead and a family history of FAP. The tumor was cultured for cytogenetic studies. A DNA linkage study using flanking and intragenic polymorphisms of the adenomatous polyposis coli (APC) gene was performed to identify the allele loss in the tumor. Germline mutation identification was by single strand conformation polymorphism analysis of exon 15 of the APC gene, with subsequent double stranded sequencing of fragments with conformational changes. A mutation-induced loss of a restriction site was used to confirm allele loss in the tumor. RESULTS: Microscopically, the tumor had desmoid features. Cytogenetic analysis of the tumor demonstrated loss of chromosome region 5(q21q22). A truncating adenomatous polyposis coli (APC) gene mutation was identified in the leukocyte DNA from the child and her affected father. Linked DNA markers suggested that the tumor had lost the maternal, wild-type allele. A mutation-induced restriction endonuclease site alteration demonstrated hemizygosity of the mutant sequence in the tumor DNA. CONCLUSIONS: These findings are compatible with the presence of a "second hit" inactivation of the APC gene and implicate this gene in the pathogenesis of desmoid tumors.

Adenomatous Polyposis Coli↗
PubMed1996

Decreased posterior tibial slope increases strain in the posterior cruciate ligament following total knee arthroplasty.

The purpose of this study was to measure the strain in the posterior cruciate ligament as a function of knee flexion angle and posterior tibial slope following total knee arthroplasty with a posterior cruciate ligament-retaining design. Posterior cruciate ligament strain was measured in seven fresh-frozen cadavers for posterior tibial slopes of 10 degrees, 8 degrees, and 5 degrees. For all three levels of tibial slope tested, strain in the posterior cruciate ligament increased with increasing flexion angle to approximately 100 degrees and then decreased with increasing flexion. The strain measured at 8 degrees posterior tibial slope was greater than that measured at 10 degrees, but the difference was not significant. The strain measured at 5 degrees posterior slope was significantly greater than strain measured at both 8 degrees and 10 degrees. This increased strain may result in altered knee kinematics and reduced range of motion at higher flexion angles.

Aged↗
PubMed1996

A Scottish family with Bazex-Dupré-Christol syndrome: follicular atrophoderma, congenital hypotrichosis, and basal cell carcinoma.

Bazex-Dupre-Christol syndrome (BDCS) is an X linked dominant disorder of the hair follicle characterised by follicular atrophoderma, multiple basal cell carcinomas, hypotrichosis, milia, and localised hypohidrosis. Follicular atrophoderma (FA) are follicular funnel shaped depressions, "ice pick marks", seen most commonly on the dorsum of the hands. We describe the first known Scottish family with this syndrome, five affected members spanning three generations. They have hypohidrosis confined to the face, coarse hair, dry skin, milia, and follicular atrophoderma. All the adults have a history of multiple basal cell carcinomas. None of them has any skeletal feature suggestive of Gorlin's syndrome. The clinical features, skin histology, and scanning electron microscopic (SEM) examination of the hair are described and illustrated. The features are compared with 15 previous reports of BDCS and four reports in which this is a possible diagnosis are also reviewed. BDCS should be considered as a differential diagnosis in patients with early onset or familial basal cell carcinomas.

Adult↗
PubMed1995

Preliminary phenotypic map of chromosome 4p16 based on 4p deletions.

We have collected and analyzed clinical information from 11 patients with chromosome 4p deletions or rearrangements characterized by various molecular techniques. Comparing the extent of these patients' deletions with their respective clinical presentations led to the proposal of a preliminary phenotypic map of chromosome 4p. This map consists of regions which, when deleted, are associated with specific clinical manifestations. Nonspecific changes such as mental and growth retardation are not localized, and probably result from the deletion of more than one gene or region. The region associated with most of the facial traits considered typical in Wolf-Hirschhorn syndrome (WHS) patients coincides with the currently proposed WHS critical region (WHSCR), but some anomalies commonly seen in WHS appear to map outside of the WHSCR. The observation of clinodactyly in 2 patients with nonoverlapping deletions allows assignment of these defects to at least 2 separate regions in 4p16. These initial observations and attempts at genotype/phenotype correlation lay the groundwork for identifying the genetic basis of these malformations, a common objective of gene mapping efforts and chromosome deletion studies.

Abnormalities, Multiple↗
PubMed1995

Antenatal screening for carriers of cystic fibrosis: randomised trial of stepwise v couple screening.

OBJECTIVE: To perform a rigorous comparative evaluation of stepwise and couple approaches to antenatal carrier screening for cystic fibrosis. DESIGN: Pragmatic randomised trial. SETTING: Hospital antenatal clinic serving a regional population. SUBJECTS: 2002 women (couples) attending for booking antenatal visit at less than 17 weeks' gestation with no family history of cystic fibrosis. INTERVENTIONS: Offering counselling and carrier testing for cystic fibrosis, either to women in the first instance (stepwise) or to couples (couple screening). MAIN OUTCOME MEASURES: Uptake rates; anxiety; knowledge of cystic fibrosis and carrier status (both partners); attitudes to health, pregnancy, the baby, and screening (both partners); and uptake of carrier testing by relatives. RESULTS: Uptake of screening was the same for both approaches (90%). After delivery most women remembered test results and their meaning, but 53/253 (21%) of those with negative results of couple testing had forgotten that repeat testing would be advisable if they had a pregnancy with a new partner. With stepwise screening women identified as carriers had high levels of anxiety when results were received (mean anxiety score 52.3). This dissipated with a reassuring partner's result (carriers' mean anxiety score 36.1) to levels similar to those receiving negative results from couple screening. Of those receiving negative results, women who had stepwise screening were significantly less anxious than those who had couple screening (mean score with result 32.1 v 35.4, 95% confidence interval for difference -4.7 to -2.1). CONCLUSIONS: Couple screening allows carriers to avoid transient high levels of anxiety, but is associated with more anxiety and false reassurance among most screenees who will test negative. Stepwise screening gives carriers and their relatives genetic information and is, in our opinion, the better method.

Anxiety↗
PubMed1995

Turner's syndrome with sex chromosome mosaicism.

The increased risk of gonadal neoplasia in cases of Turner's syndrome with sex chromosome mosaicism and the presence of Y chromosome material emphasises the need for a diligent search and removal of the streak gonads. One such case is reported here.

Adult↗
PubMed1995

Effects of hydroxyapatite tricalcium phosphate coating and intracancellous placement on bone ingrowth in titanium fibermetal implants.

The purpose of this study was to compare the host-bone response to hydroxyapatite/tricalcium phosphate (HA/TCP)-coated and noncoated titanium fibermetal implants placed in a load-sharing cancellous bone environment of the distal femurs of rabbits. The influence of implantation site was also investigated by comparing these intracancellous implants with intramedullary implants evaluated in a previous study. Three parameters were measured: percentage implant perimeter surface length in contact with new bone, percentage internal fibermetal surface length in contact with ingrown bone, and percentage of available pore space filled with bone. The HA/TCP coating significantly accelerated and increased bone ongrowth, new bone formation on the perimeter and internal surface of the implants. This effect was evident as early as 2 weeks after implantation. In contrast, there was no difference between HA/TCP-coated and noncoated implants in the bone ingrowth parameter, percentage of available pore space filled with bone, or pull-out strength. Scanning electron microscopy in the backscatter mode demonstrated that new bone formed directly onto the HA/TCP-coated fibers and did not usually form directly on noncoated fibers. Analysis of fluorochrome labeling revealed that bone formation in weeks 1 through 4 was primarily woven and thereafter lamellar. Compared with intramedullary placement, intracancellous placement significantly accelerated the apposition of bone to the perimeter and internal surface of HA/TCP-coated implants and both accelerated and increased bone ingrowth as a percentage of available pore volume. These data show that the host response to titanium fibermetal implants is influenced both by HA/TCP coating and by the implantation site.

Animals↗
PubMed1995

Family studies in chromosome 22q11 deletion: further demonstration of phenotypic heterogeneity.

We describe three unrelated, Scottish infants with the velocardiofacial/DiGeorge syndrome, all of whom have deletions of chromosome 22q11. Two of the infants had inherited the deletion from their mothers; the third infant's mother had clinical features although a deletion was not demonstrable in her. One infant had craniosynostosis associated with broad thumbs which may be a separate familial trait; however, at least one other 22q11 deleted individual with craniosynostosis is known and it is possible that craniosynostosis is a rare feature of this deletion syndrome. The second infant is the third reported case with isolated hypoparathyroidism and dysmorphic features associated with the 22q11 deletion. The variable clinical phenotype of these families with 22q11 deletion is discussed and compared with other reported families.

Adult↗
PubMed1995

A four generation hidrotic ectodermal dysplasia family: an allelic variant of Clouston syndrome?

A four generation Scottish family with hidrotic ectodermal dysplasia affecting predominantly teeth, skin and hair is described. Hypo- or oligodontia of the secondary dentition by late adolescence was characteristic and two individuals had multiple natal teeth. Flexural acanthosis nigricans during childhood and early adolescence is a feature in some of the women. All affected individuals produced sweat, but heat tolerance was variable. Hypoplasia of the pilosebaceous units was found on light microscopy in one subject. Scalp hair was thin and slow growing (but adult females described much improved quality during pregnancy) and body hair was scanty. Scanning electron microscopy of hair samples showed abnormal cuticular appearances consistent with a primary defect affecting keratin structure. The nails were normal. Relative macrocephaly due to hyperostosis of the cranial vault was variably present. Short stature (5-10th centile) present in some cases is possibly a separate familial trait. The family demonstrates overlapping features with Clouston syndrome. In Clouston syndrome, however, alopecia can be severe, palmarplantar hyperkeratosis is usually present, and hypo/oligodontia is not a prominent feature.

Adult↗
PubMed1995

Ascertainment of myotonic dystrophy through cataract by selective screening.

Myotonic dystrophy (DM) almost always results from the expansion of an unstable (CTG)n repeat. The mutation can be detected directly. Affected patients with cataracts may have minimal additional signs of the disorder, but all are at risk of life threatening complications. We have studied the efficacy of detecting new families with myotonic dystrophy by selectively screening cataract patients. Selection criteria were: age under 60 with no obvious precipitating factor (except non-insulin dependent diabetes mellitus (NIDDM)); patients of any age with other signs suggestive of myotonic dystrophy detected by the ophthalmologist. Ninety-six patients were tested prospectively; 17 others under 55 were screened retrospectively. All patients were counselled by a clinical geneticist before testing. The patients' DNA was analysed using the DNA probe/restriction enzyme combinations GB2.6/EcoRI, KB1.4/BglI and polymerase chain reaction (PCR). Six patients have been found to have a mutation, three (3.1%) in the prospective group and three (17.6%) in the retrospective group. Three of these patients had minimal myotonic dystrophy and three had classical DM.

Adolescent↗
PubMed1995

The development of a computerized LAN-based investigational drug information database.

A computerized LAN-based investigational drug information database, IRxBase, was developed at the University of Pittsburgh Medical Center to facilitate healthcare professionals' access to investigational drug information. Healthcare professionals at the medical center were surveyed to identify current problems in accessing investigational drug information. The survey reflected that before the implementation of the database, the medical center lacked a systematic approach to providing protocol-specific investigational drug information. Although investigational drug information software programs are commercially available, they provide limited information and few are protocol-specific. IRxBase offers an efficient means for the widespread provision of investigational drug information with advantages of accessibility, ongoing data entry, and preservation of confidentiality.

Attitude of Health Personnel↗