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Biomedical subjects

J G Hall

Publications and source records attributed to J G Hall.

At least 19 recordsLinked to original sources
PubMed1992

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↗
PubMed1992

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

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↗
PubMed1991

IgA antibodies in the bile of rats. V. Primacy of the GALT as a source of IgA.

In each of a series of rats the common bile duct and the thoracic duct (cisterna chyli) were cannulated so that both bile and thoracic duct lymph could be collected quantitatively for several hours. The concentrations of IgA in samples of lymph and bile were measured by radioimmunoassay so that the output of IgA per unit time could be calculated. Although the output of IgA in the lymph did not decline significantly, the output in the bile fell so that by 2 hr it had been reduced to less than 20% of the peak value. Similar experiments in rats which had been immunized actively by injecting antigens into the GALT showed a corresponding rapid decline in titres of specific biliary antibodies after fistulation of the thoracic duct. The low levels of IgA in the bile of rats that had been drained of thoracic duct lymph were restored quickly to normal values by the intravenous infusion of a volume of thoracic duct lymph equal to that which had been lost; this restoration was transient, and the concentration of IgA in the bile soon declined again after the infusion ceased.

Animals↗
PubMed1990

A quick method for obtaining lymph-borne dendritic macrophages from rats.

After conventional cannulation of the thoracic duct (cisterna chyli) of rats, the mesenteric nodes were frozen solid by the application of solid carbon dioxide and a metal probe that had been cooled to the temperature of liquid nitrogen. This procedure destroyed the functional integrity of the node so that peripheral intestinal lymph, rich in dendritic macrophages flowed, unaltered, into the thoracic duct. In this way peripheral intestinal lymph could be collected immediately and the time-consuming and expensive two-stage procedure of conventional surgical lymphadenectomy was avoided.

Animals↗
PubMed1990

Three-generation dominant transmission of the Silver-Russell syndrome.

We report on 7 patients with the Silver-Russell syndrome (SRS) in two 3-generation families. Three patients in each of the families had an undergrowth of the left side of the body when compared with the normal right side. The clinical courses were mild as compared to the severity sometimes described in sporadic cases. These patients and a review of 190 SRS cases from the literature showed that there were 23 families in which 38 patients had completely expressed SRS. In 17 of the families, multiple maternal relatives had complete or partial expressions of the SRS. Most SRS patients have been reported to occur sporadically; however, of the 197 propositi analyzed, 19% had more than one affected individual in a family and several different modes of inheritance could have been responsible. Two families (8.7%) had spontaneous dominant mutations (twins) and possible autosomal recessive transmission was present in 4 families (17.4%). Because no male-to-male transmission has yet been documented in the 21 families in the literature and the two families reported here, X-linked dominant inheritance is a possibility in 17 families (74%). Thus, although sporadic occurrences and genetic heterogeneity appear to be involved in the SRS, dominant inheritance may be a major causal factor.

Adult↗
PubMed1990

Familial renal hypophosphatemia, minor facial anomalies, intracerebral calcifications, and non-rachitic bone changes: apparently new syndrome?

We report on two brothers with renal hypophosphatemia, intracerebral calcifications, minor facial anomalies, and short distal phalanges. The children presented with recurrent dental abscesses; one had premature closure of the anterior fontanelle. Biochemical findings included hypophosphatemia and elevated serum alkaline phosphatase with normocalcemia. Blood levels of parathyroid hormone, 1,25(OH)2 and 25(OH) vitamin D levels were normal; TRP (the fractional tubular reabsorption of PO4) and TmP/GFR (the tubular maximum rate of PO4 reabsorption in relation to GFR) were low. Both parents had a normal serum phosphate and brain CT scan without evidence of calcifications. This apparently new syndrome of renal hypophosphatemia associated with intracerebral calcifications appears to be inherited as either an autosomal recessive or an X-linked trait.

Brain↗