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Biomedical subjects

A D Roses

Publications and source records attributed to A D Roses.

At least 253 records · Page 14Linked to original sources

Cellular localization of messenger RNA encoding amyloid-beta-protein in normal tissue and in Alzheimer disease.

Amyloid precursor protein (APP) gene encodes the short peptide fragment amyloid-beta-protein present in senile plaque cores, cerebrovascular amyloid, and intracellular neurofibrillary tangles in Alzheimer disease (AD). Using in situ hybridization with biotin-labeled RNA probes, we found distinctive patterns of APP gene expression in different regions of postmortem human brain. Strong hybridization signal for APP messenger RNA (mRNA) was detected in specific classes of neurons, fascicular oligodendroglia, satellite glia, and presumptive microglia. Weaker signal was seen in other neuronal classes, fascicular astrocytes, and vascular endothelial cells, but no signal was seen in protoplasmic astrocytes. Human thymus also shows a restricted pattern of hybridization with high signal in reticular epithelial cells, and much lower signal in lymphocytes. In AD patients, neuronal hybridization for APP mRNA was specifically increased in hippocampus, but not cerebellar and visual cortex when compared to hybridization for neuron-specific enolase mRNA. Most neurons with neurofibrillary tangles had strong APP mRNA signal. These results suggest that APP gene expression is highly regulated in normal tissue, that many different cell classes in brain express the APP gene, and that neuronal expression may increase specifically in brain regions where widespread injury occurs in AD. Amyloid deposits in brains of AD patients might be explained by local production of precursor protein in endothelial cells, neurons or glia.

Aged↗

Clinical and genetic investigation in autosomal dominant limb-girdle muscular dystrophy.

Limb-girdle muscular dystrophy is a syndrome of progressive myopathic weakness affecting shoulder and hip girdle and proximal arm and leg muscles. The disease occurs either sporadically or inherited as an autosomal recessive trait. Autosomal dominant inheritance is rare. We report a large family with apparent autosomal dominant inheritance. Sixteen members were affected with a disease characterized by proximal weakness, leg greater than arm, onset in the third decade, elevated CK and CK MB levels, and myopathic EMGs and muscle biopsies. Linkage analysis revealed no conclusive linkage.

Adolescent↗

Myotonic dystrophy: update on progress to define the gene.

Using standard likelihood linkage techniques, the gene for dystrophia myotonica has been localized to the proximal long arm of chromosome 19. Several large families provided the substrate for detecting linkage of restriction fragment length polymorphisms which were developed in the laboratory from flow-sorted chromosome 19 genomic libraries. In over 500 family members from five families only a single cross-over with ApoC2 was detected. Thus a useful probe for antenatal and preclinical diagnosis is now available. Details of the strategy employed within the framework of clinical diagnosis, genetic epidemiology and recombinant DNA techniques is described.

Child↗

Update on the molecular genetics of Duchenne muscular dystrophy.

Three separate lines of evidence led to the assignment of the Duchenne muscular dystrophy (DMD) gene to the 21.2 band on the short arm of the X chromosome. A portion of the putative gene, thought to extend over 1-2 million base pairs has been recently cloned. DNA probes from the Xp21.2 region detect large deletions in 5-20% DMD boys and are presumed to lead to the DMD phenotype in those individuals. Deletions have also been noted in the DNA of patients with Becker muscular dystrophy. These exciting developments have a direct bearing on carrier detection and prenatal diagnosis. Prenatal diagnosis in deletion families approaches greater than 99% accuracy and can be utilized to save 50% of normal male fetuses carried by carrier mothers who would otherwise choose to abort all male fetuses.

Cloning, Molecular↗

Localization of neuron-specific enolase (NSE) mRNA in human brain.

In situ hybridization with biotinylated DNA and RNA probes derived from the 3' untranslated region of human neuron-specific or gamma gamma-enolase (NSE) permits histochemical detection of NSE mRNA in autopsy samples of human brain. In both aged controls and Alzheimer's disease (AD) patients, NSE probe hybridized with variable intensity to nerve cells in visual cortex and cerebellum, but not to glial or liver cells. These results provide evidence that NSE mRNA is expressed in neurons in human brain tissue, pattern of NSE mRNA expression in unaffected brain regions in AD is qualitatively normal, and NSE mRNA expression may vary widely among different classes of neurons.

Adult↗

Chorea-acanthocytosis: a report of three new families and implications for genetic counselling.

Chorea-acanthocytosis (CHA) is a rare inherited neurologic disorder with peripheral red cell acanthocytes and normal serum lipoprotein levels. To date, 8 families with the disorder have been reported outside of Japan. We describe 4 patients in 3 families with CHA and review the clinical presentations in previous reports. In addition, we report magnetic resonance imaging scans in these patients. The pattern of inheritance in these families is most likely autosomal recessive. Obligate heterozygotes do not have acanthocytes on wet preparation under phase microscope. Two of 3 propositi were initially diagnosed as having Huntington chorea. Chorea-acanthocytosis is an important differential in the diagnosis of Huntington chorea and should be considered in families without a family history. The paucity of families with CHA reported to date may represent lack of recognition.

Acanthocytes↗

Linkage studies in peripheral neurofibromatosis.

Peripheral neurofibromatosis (NF) is one of the most common major genetic disorders in man. Its chromosomal location is unknown and questions regarding such factors as genetic heterogeneity remain unanswered. We have ascertained and sampled several large multi-generation families for linkage studies including one family of 66 subjects, 28 of whom were affected with NF. Recombinant DNA studies of several restriction fragment length polymorphisms (RFLPs) including C3, ApoC2, pBam34 (D19S6], HAUP[APRT], pE40-1 [D11521], Hp[Hp2 alpha], LDR92, and LDR111 failed to show a significant linkage (Z [lod score] greater than or equal to 3.00) in this family. In addition, the results excluded areas of the genome around the marker loci (Z greater than or equal to - 2.00) as potential sites for linkage. The maximum Z obtained with the markers was for Hp at theta (maximum recombination fraction) = 0.20 and Z = 0.399. We are now in the process of screening additional RFLPs and families for linkage to NF.

Genetic Linkage↗

Linkage analysis of peripheral neurofibromatosis to DNA markers on chromosome 8.

Linkage relationships of the gene for peripheral neurofibromatosis (NF) were assessed in a large American Caucasian pedigree using two DNA markers located on chromosome 8. Linkage to the thyroglobulin locus, located at 8q24, was excluded (lod less than or equal to -2.0) to 21 cM. Data obtained for the tissue plasminogen activator locus, located at 8p12, excluded linkage to 4 cM. These results exclude between 20 to 30% of chromosome 8 as a possible map location for the NF gene in this family. Comparison of the two DNA markers excluded their linkage to 0.5 cM.

Chromosomes, Human, Pair 8↗

Hereditary motor and sensory neuropathy, X-linked: a half century follow-up.

The existence of an X-linked sensorimotor peripheral neuropathy has been debated. We reevaluated the original family, and present data on 13 affected males and 25 obligate or probable heterozygous females, documenting the devastating nature of the disease in the men and the extremely variable degree of clinical involvement in the carriers. Use of DNA probes indicates that the gene lies in the DXYS1-p58-1 region of the X-chromosome.

Adolescent↗

Familial inheritance of a DXS164 deletion mutation from a heterozygous female.

Restriction-fragment-length-polymorphism analysis was used to examine a female who is segregating for Duchenne muscular dystrophy (DMD) and a deletion of the DXS164 region of the X chromosome. The segregating female has no prior family history of DMD, and she has two copies of the DXS164 region in her peripheral blood lymphocytes. The following two hypotheses are proposed to explain the coincidence of the DMD phenotype and deletion of the DXS164 region in her offspring: (1) she may be a gonadal mosaic for cells with two normal X chromosomes and cells with one normal X chromosome and an X chromosome with a deletion of the DXS164 region; and (2) she may carry a familial X;autosome translocation in which the DXS164 region is deleted from one X chromosome and translocated to an autosome. The segregation of DMD and the DXS164 deletion in this family illustrates the importance of extended pedigree analysis when DXS164 deletions are used to identify female carriers of the DMD gene.

Chromosome Deletion↗

X-linked neuropathy: gene localization with DNA probes.

We used probes for DNA polymorphisms on the X chromosome to study genetic linkage in four families with X-linked neuropathy. Despite clinical variability, all four families showed the same linkage pattern. We found evidence in each family of linkage to the marker DXYS1 on the proximal long arm of the X chromosome, as reported by others. We also found linkage to p58-1 (DXS14) on the proximal short arm. We found only loose linkage or nonlinkage to nine other markers located elsewhere on the chromosome. Our analysis places the gene defect for this disorder in the region of DXYS1 and p58-1, near the centromere of the X chromosome.

DNA↗

Promiscuous expression of myosin in myotonic dystrophy.

The pathologic changes in myotonic dystrophy (DM) skeletal muscle biopsies have been analyzed at both the histochemical and molecular level. A histochemical stain for pretyping single fibers in conjunction with sodium dodecyl sulphate-polyacrylamide gel electrophoresis allowed biochemical differences to be pinpointed in specific histochemical fiber types. These biochemical differences can be related to histochemical changes in fiber type observed in cross-section of the DM biopsies. Such changes included specific fiber type atrophy, hypertrophy, and disproportion. The pathogenesis of DM appears to be characterized by a large increase in the number of promiscuous fibers, that is, those fibers that express both fast and slow myosins. This promiscuity, which is rare in control muscle (less than 2%), is also prevalent at high levels in some family members at risk for DM. The observed promiscuity, although probably not a primary effect of DM, appears to be linked to the histochemical changes in fiber type observed in the DM biopsies.

Adolescent↗

A method to quantitate Coomassie blue-stained proteins in cylindrical polyacrylamide gels.

A method for the quantitation of Coomassie blue-stained proteins in cylindrical polyacrylamide gels is described. It involves an elution of the dye with an 80% methanol solution in a sealed Pyrex tube at 100 degrees C for 3 h and a measurement of its concentration at 585 nm. Using a 6.5% polyacrylamide gel and bovine serum albumin as a protein standard, the curve of absorbance of the dye solution as a function of the amount of protein was observed to be linear up to 30-40 micrograms of protein and as little as 0.8-1.0 micrograms of protein could be measured. The validity of the method was indicated by the values obtained for the relative proportions of the human erythrocyte membrane proteins. Using this method, the color yields of several proteins varying widely with respect to their size, amino acid composition, and carbohydrate content were determined in a 6.5% polyacrylamide gel. The results showed that they were generally the same except for proteins having a high carbohydrate content which were significantly lower.

Animals↗