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Biomedical subjects

J G Hall

Publications and source records attributed to J G Hall.

At least 73 records · Page 4Linked to original sources

Genomic imprinting: summary of an NICHD conference.

Compelling evidence for genomic imprinting as a pathogenetic mechanism in humans mandates re-evaluation of every genetic or multifactorial disease for parent-of-origin effects. In an expanding list of malformation syndromes, cancers, growth abnormalities, and chromosomal disorders, phenotypes may be determined by source rather than content of transmitted DNA. A multidisciplinary conference held on April 13-14, 1992, reviewed the substantial impact of genomic imprinting in mouse development and discussed in role in human pregnancy, childhood cancers, chromosomal translocations, X-inactivation, and several disorders associated with mental retardation. Topics for future research include the mechanism, timing, reversibility, and homology of the imprinting process.

Animals↗

The stimulation by dendritic cells of host-versus-graft reactivity in vivo.

Dendritic cells (DC) isolated from peripheral intestinal lymph of inbred Wistar rats were injected into the hind footpads of Hooded CBH/Cbi rats. Administration of 10(4) and 5 x 10(5) allogeneic DC produced approximately six-fold increase in popliteal node weight. This is only marginally greater than that caused by similar doses of syngeneic DC and about 30% greater than that caused by allogeneic mononuclear cells. The data indicated that allogeneic DC were not effective stimulators of host-versus-graft reactions in this assay.

Animals↗

Arthrogryposis, ophthalmoplegia, and retinopathy: confirmation of a new type of arthrogryposis.

Arthrogryposis multiplex congenita is a heterogeneous condition and many different types are clinically recognisable. Recently, a new type of autosomal dominant arthrogryposis was described in a father and son. We report on a male patient with similar clinical features, confirming this distinct type of arthrogryposis. The condition is characterised by congenital contractures of the hands and feet with diminished or absent phalangeal creases, ophthalmoplegia, a rigid trunk, deep set eyes, and (in the oldest patient) an abnormal electroretinogram. Differential diagnosis from amyoplasia, the different types of distal arthrogryposis, and symphalangism is discussed.

Adolescent↗

CATCH 22.

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Abnormalities, Multiple↗

Nontraditional inheritance.

It has become clear in recent years that not all forms of inheritance follow classical mendelian laws regarding the equal contribution from both parents. These nontraditional modes of inheritance and gene expression include cytoplasmic inheritance, mosaicism, uniparental disomy, and genomic imprinting. All of these have been implicated in human genetic disorders and cancers and thus need to be kept in mind when trying to understand unusual observations in the clinic as well as when providing genetic counseling.

Chromosome Aberrations↗

Fellowships and career development in dysmorphology and clinical genetics.

This article sets forth some guiding principles for the initiation of a productive and satisfying academic career as a clinical researcher in the areas of dysmorphology, teratology, and clinical genetics. It assumes that the fellow in dysmorphology and clinical genetics is genuinely committed to the pursuit of a career in this area, but these general principles are certainly relevant to other medical specialties. It is important for pediatricians to consider careers in this area because the need for dysmorphologists and clinical geneticists will continue to increase during the foreseeable future, and the current opportunities for such training are limited.

Career Mobility↗

Syndrome of mental retardation and distal arthrogryposis in sibs.

Two sisters presented with a syndrome of characteristic facial anomalies and distal arthrogryposis. The older sister is now 4 years old and is severely mentally retarded. Her sister died of respiratory failure due to hypoplastic lungs shortly after birth. The occurrence of this potentially lethal syndrome in 2 sisters with unaffected parents suggests autosomal recessive inheritance.

Arthrogryposis↗

Deletion of chromosome 21 and normal intelligence: molecular definition of the lesion.

Application of a method for the fine structure analysis of unbalanced chromosomal rearrangements using quantitative Southern blot analysis has established that an individual of normal intelligence and largely normal appearance has a significant interstitial deletion of chromosome 21. Using high resolution cytogenetic analysis and molecular analysis with five single copy DNA sequences unique to chromosome 21 and a probe for human SOD1 (CuZn, superoxide dismutase), we find that the deletion extends to the border of bands 21q11.1-11.2. and extends to the border of bands 21q21.2-q21.3. The latter border is established molecularly by the presence of two copies of SOD1, previously mapped to band 21q22.1, and of four single copy sequences known to be located distal to this region. The presence of SOD1 was confirmed by enzyme dosage analysis. These findings demonstrate that deletion of close to 20,000 kb of autosomal material is compatible with normal intelligence. Further, they suggest that chromosome 21 may include a large region of relative developmental neutrality whose molecular basis may now be investigated. Because of the limits of even high resolution cytogenetic analysis, fine structure molecular analyses of this type will be necessary to reliably detect and define similar small chromosomal deletions or insertions. The molecular definition of such aneuploidy provides the basis for increasing the resolution of the human physical genetic map.

Blotting, Southern↗

Genomic imprinting.

In the last few years, the importance of genomic imprinting as a basic biological phenomenon has become clear. Work from different areas has demonstrated that parent-of-origin differences in phenotype occur on a regular basis. This article summarizes some of the recent advances made in this field.

Animals↗

A new form of autosomal dominant arthrogryposis.

We report a man and his son with congenital limb contractures, limitation of ocular movements, and an electroretinal abnormality. They appear to have an autosomal dominant form of arthrogryposis, distinguishable from other previously classified forms of this disorder.

Adult↗

The relief of biliary obstruction in experimental rats by diverting the hepatic lymph into the duodenum.

Twelve days after their common bile ducts had been ligated rats were icteric and their hepatic lymph nodes and lymph ducts were two or three times their normal size. Cannulation of the hepatic lymph ducts of these rats yielded bile-stained lymph which flowed at nine times its normal rate. As the lymph flowed, so the concentration of bilirubin in the blood declined; after 5 days the rats were no longer jaundiced, and by day 11 there were normal amounts of bilirubin in the blood. In another series it proved possible on seven occasions to insert the free end of the hepatic lymph cannula into the duodenum at the time that the bile was obstructed. Five of these animals showed no increase in serum bilirubin and remained in good condition until the experiments were terminated up to 61 days later. It seems that the effects of biliary obstruction can be mitigated by shunting the hepatic lymph into the intestine.

Animals↗

The new genetics and its relevance to orthopedics.

The recent advances in genetics have practical importance for patients with orthopedic problems. Specific genes are being isolated, mapped to chromosomes, and defined. Surgical specimens can be used for genetic studies to define specific genetic abnormalities. Making specific genetic diagnoses is important for appropriate care of the patient and the family.

Connective Tissue Diseases↗