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Biomedical subjects

M E Hodes

Publications and source records attributed to M E Hodes.

At least 19 recordsLinked to original sources

Familial occurrence of renal and Müllerian duct hypoplasia, craniofacial anomalies, severe growth and developmental delay.

Absence of the kidneys and of the Müllerian structures has been reported in many patients. We report on a brother and sister, born to nonconsanguineous parents, with renal hypoplasia, Müllerian duct hypoplasia, and strikingly similar facial abnormalities. Both sibs have severe growth and developmental retardation. We think that the unique clinical findings in these sibs represent a new syndrome. The embryological and genetic implications of this condition are discussed.

Abnormalities, Multiple

New variant in exon 3 of the proteolipid protein (PLP) gene in a family with Pelizaeus-Merzbacher disease.

A C--greater than G transversion has been found in exon 3 of the PLP gene of affected males and their mother in a single sibship with Pelizaeus-merzbacher disease (PMD). The transversion should not result in an amino acid change in the protein but it does result in the loss of a HaeIII restriction endonuclease cleavage site. It is concordant with the disease in this family. One-hundred-ten unrelated X chromosomes are negative for this mutation. No other sequence defect was found in the PLP exons of the affected males. The cause of disease in this family remains unknown, but the association between this rare mutation and PMD is intriguing. The mutation can serve as a marker for following segregation of the PLP gene.

Base Sequence

A non-organic and non-enzymatic extraction method gives higher yields of genomic DNA from whole-blood samples than do nine other methods tested.

We compared ten methods for extraction of DNA from whole blood. Nine methods require incubation with either enzymes or treatment of organic solvents or both. The 'Rapid Method' (RM) (Method 10) avoids the use of organic solvents (phenol/chloroform) and eliminates completely the use of proteinase K. Thus, the time and cost of DNA extraction are reduced significantly. This is accomplished by salting out and precipitation of the cellular proteins in saturated sodium chloride. This method takes less than an hour to completion, without compromising the yield or the quality of DNA. Using RM, we can make DNA from 0.1 ml of whole blood and as little as 0.5 ml of blood yields DNA sufficient to run a few Southern blots. The RM can also be applied to packed cells. The DNA is free of RNA, protein and degrading enzymes. The uncut DNA runs as a typical slow-migrating, high-molecular-weight and undegraded species in an agarose gel. The DNA is suitable for digestion by various restriction endonucleases. This procedure works equally well with fresh blood samples and with those that are stored at 4 degrees C and -70 degrees C. To our knowledge the RM reported here is the safest, fastest and most quantitative and economical method for preparation of DNA from whole blood and cells.

Chemistry Techniques, Analytical

Linkage of the Indiana kindred of Gerstmann-Sträussler-Scheinker disease to the prion protein gene.

The Indiana kindred variant of Gerstmann-Sträussler-Scheinker disease has amyloid plaques that contain prion protein (PrP), but is atypical because neurofibrillary tangles like those of Alzheimer disease are present. To map the position of the disease causing gene, we used three markers for linkage analyses. A missense mutation at codon 198 of the PrP gene (PRNP) is found in all definitely affected individuals and yields a maximum lod score of 6.37 (theta = 0). The disease also is concordant with the two other PRNP-region markers. These results demonstrate tight linkage of the disease-causing gene to PRNP and support the hypothesis that the codon 198 mutation is the cause of IK-GSS. Our studies also suggest that methionine/valine heterozygotes at PRNP codon 129 have a later age of onset of the disease than codon 129 valine/valine homozygotes.

Adult

Mutant prion proteins in Gerstmann-Sträussler-Scheinker disease with neurofibrillary tangles.

Two families with Gerstmann-Sträussler-Scheinker disease (GSS) are atypical in possessing neocortical neurofibrillary tangles (NFTs), which are few or absent in other kindreds with GSS, in addition to amyloid plaques that react with prion protein (PrP) antibodies and protease-resistant PrP accumulation in the brain. A leucine substitution at PrP codon 102 has been genetically linked to GSS in some families. We examined the PrP gene in these families. A serine for phenylalanine substitution was found at codon 198 in the Indiana patients; arginine for glutamine substitution at codon 217 in the Swedish patients. These mutations in PrP are the first to be associated with the appearance of both PrP amyloid plaques and neocortical NFTs in GSS patients.

Adult

A new mutation in the proteolipid protein (PLP) gene in a German family with Pelizaeus-Merzbacher disease.

A C-to-T transition in exon 4 of the PLP gene was found in 2 affected males and two obligate carriers in a German family with Pelizaeus-Merzbacher disease. The mutation, which causes loss of an HphI site and changes amino acid 155 from threonine to isoleucine, was absent from 108 normal chromosomes. There are 5 concordances and 1 discrepancy between these results and those obtained by magnetic resonance imaging in this family.

Diffuse Cerebral Sclerosis of Schilder

[Screening and isolation of the cerebellar specific expressed mRNA in mouse: subtractive hybridization by phenol emulsion reassociation technique].

There are extremely complicated and numerous gene expressions in mammalian brains. Each region of the brain contains a set of mRNA expressed only in that region and these mRNA would be related to presumed region of specific function. Genes preferentially expressed in cerebellum (CB) are therefore the reasonable candioate genes for site of genetic lesions in CB neurodegenerative disorders. In this study, the subtractive hybridization was introduced into screening and isolating CB specific mRNA. Testing CB and front cortex (CTX) cDNA libraries were built, which covered most low abundantly expressed mRNA. By applying over 100 fold excessive CTX and liver single strand cDNA to the CB double strand cDNA, subtractive hybridization was carried out by phenol-emulsion-reassociation-technique (PERT), in which the common expressed housekeep genes would be eluted by restrict site ligation, and CB specific cDNA flanking with EcoRI site in both ds cDNA ends could be cloned into lamda gill phage. PERT subtraction reduced CB cDNA libraries from initial 5.15 x 10(6) to remaining 2.5 x 10(3) recombinants, which were most likely CB specific expressed cDNA. Random Twenty recombinants (over 2 kb inserts) were amplified randomly by polymerase chain reaction (PCR) and were hybridized with CB cDNA and liver cDNA probes in dot blot. 14 inserts positively hybridized with CB cDNA probe and only 3 inserts showed signals with liver cDNA probe. Colony blot presented similar results. 10 cDNA clones which affinited to CB cDNA probe were selected for the Northern blot. In five tissures, 2 cDNA clones binded only in CB mRNA channel, 6 were proved preferential expression in CB and low abundant expression in 4 other tissues, 1 clone was a housekeep gene and 1 could not be detected in all tissues. The partially sequencing of clone PC7 and PD8 were introduced into Computer Gene Bank Data Base. No homologous complements were found between these two clones and over ten thousands genes that have been sequenced. The two clones were newly reported. According to our experiment, we believe that: 1) CB specifically expressed mRNAs are much less than expected comparing with other brain regions; 2) most of CB mRNA expressions are in a preferential way other than unique expression.

Animals

Coupled reverse transcription-polymerase chain reaction (RT-PCR) as a sensitive and rapid method for isozyme genotyping.

We have developed a highly sensitive and rapid coupled reverse transcription-polymerase chain reaction (RT-PCR) technique for detection of alpha-amylase-encoding gene transcripts and for distinguishing between the human salivary (AMY1) and pancreatic (AMY2) gene transcripts. The two genes are 93-94% homologous. However, the AMY1 gene has an additional exon known as exon S, and an extra 32 bp in exon 1. Genotyping of the different AMYs by RT-PCR was based on this unique feature of the AMY1 mRNA sequence. Detection of AMY gene (AMY1 and AMY2) transcripts in cellular RNA was achieved with a set of primers common to both human AMY1 and AMY2 genes and derived from the exon 3-4 regions. In contrast, AMY1 gene transcripts were distinguished from the pancreatic AMY2 gene transcripts by use of primers specific to the exon S-1 regions of the AMY1 gene. To distinguish AMY1 transcripts from a mixture of AMY1 and AMY2, use was made of the differences in the ethidium bromide-stained agarose gel patterns obtained after digestion of the amplified exon 3-4 fragments with TaqI. AMY gene transcripts were detectable by autoradiography in RT-PCR amplified DNA obtained from as little as 5 pg of human pancreatic or parotid total RNA. A comparison of sensitivity of Northern blotting vs. RT-PCR suggested that the RT-PCR method is about 3-6 x 10(3)-fold more sensitive than Northern blotting in detecting AMY gene transcripts in human pancreatic total RNA.

Amylases

Branchio-oto-renal dysplasia and branchio-oto dysplasia: two distinct autosomal dominant disorders.

Three families are presented, one with branchio-oto-renal dysplasia (BOR) and two with branchio-oto dysplasia (BO). The former syndrome is characterized by external ear malformations, cervical fistulae, mixed hearing loss and renal anomalies of varying severity. The latter syndrome differs in that there are no renal anomalies and that the sensorineural component of the hearing loss may be absent. The external ear malformations are quite variable in both syndromes. Evidence is presented which supports the idea that these two syndromes are not phenotypic variants of the same autosomal dominant mutation but distinct disease entities. The BOR syndrome appears to belong to a larger group of hereditary ear dysplasia-renal adysplasia syndromes that must be carefully ruled out in all patients with familial branchial arch malformations as well as in the parents and siblings of infants with "Potter facies" in the presence of auricular malformation and renal adysplasia.

Abnormalities, Multiple

Clinical experience with trisomies 18 and 13.

The clinical, cytogenetic, dermatoglyphic, and postmortem observations of the 29 cases of trisomy 18 and 19 cases of trisomy 13 seen in the Department of Medical Genetics from 1963-76 are summarised. Chromosomes were studied in all and 30 were banded. One patient had tertiary trisomy 18 and 8 had translocations of chromosome 13. The features of these patients are described and the syndromes compared with each other and summaries found in the literature.

Chromosome Aberrations