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Biomedical subjects

R M Liberfarb

Publications and source records attributed to R M Liberfarb.

24 records · Page 2Linked to original sources
PubMed1978

Down syndrome in two of three triplets.

This is the first report to our knowledge of trisomy 21 in two members of a set of triplets. The two with Down syndrome are monozygous; the other triplet is not identical. These triplets were born to a 22-year-old woman in whose family there have been six sets of twins (four like-sex) since 1775. Neither parent has any chromosomal abnormality. Zygosity estimates in the triplets are derived from studies of red blood cell antigens and HLA typing. Twinning has been reported in association with many different chromosome abnormalities. It has been suggested that the incidence of Down syndrome among twins is significantly higher than among singletons. It seems likely that some families have a heritable predisposition to both twinning and chromosome abnormalities.

Chromosome Banding↗
PubMed1978

Chromosome 6q- and associated malformations.

A dysmorphic retarded fourteen-mont-old female with partial deletion of the long arm of chromosome 6 is presented. The breakpoint in 6q was in region 2, probably at band 5. Eight other infants with a deletion involving the long arm of chromosome 6, including five with a ring chromosome 6, have been reported. The affected individuals have in common microcephaly, micrognathia, hypotonia and psychomotor retardation, but do not appear to have a distinctive phenotype.

Abnormalities, Multiple↗
PubMed1970

Isolation, characterization, and genetic analysis of mutator genes in Escherichia coli B and K-12.

Twenty-one Mut mutants were obtained from Escherichia coli B (B/UV) and K-12 (JC355) after treatment with mutagens. These Mut strains are characterized by rates of mutation to streptomycin resistance and T-phase resistance which are significantly higher than the parental (Mut(+)) rates. Mutator genes in 12 strains have been mapped at three locations on the E. coli chromosome: one close to the leu locus; five close to the purA locus; and six close to cysC. In addition, eight mutator strains derived from E. coli B/UV are still unmapped. Some effort was made to deduce the mode of action of the mutator genes. These isolates have been examined for possible defects in deoxyribonucleic acid repair mechanisms (dark repair of ultraviolet damage, host-cell reactivation, recombination ability, repair of mitomycin C damage). By using transductional analysis, it was found that the ultraviolet sensitivity of NTG119 and its mutator property results from two separate but closely linked mutations. PurA(+) transductants that receive mut from NTG119 or NTG35 are all more sensitive to mitomycin C than is the PurA recipient. Unless transduction selects for sensitivity, a probable interpretation is that defective repair of mitomycin C-induced damage is related to the mode of action of mut in these transductants and the donor. Abnormal purine synthesis may be involved in the mutability of some strains with cotransduction of the mutator properly and purA (100% cotransduction for NTG119). Three mutators are recombination-deficient and may have a defective step in recombination repair. One maps near three rec genes close to cysC.

Chromosome Mapping↗
PubMedDate not supplied

Histopathology of the ears, eyes, and brain in Norrie's disease (oculoacousticocerebral degeneration).

Norrie's disease is an x-linked recessive disorder characterized by progressive oculoacousticocerebral degeneration. The light and electron microscopic changes in the temporal bones, eyes, and brain of an affected 77-year-old man who suffered from bilateral profound sensorineural hearing loss, blindness, and mental retardation are described. The inner ears showed marked atrophy of the stria vascularis, severe degeneration of hair cells and cochlear neurons, and connective tissue proliferation in the spiral ganglion, osseous spiral lamina, and walls of the membranous vestibular labyrinth. The eyes showed detached retinae, dense proliferation of fibrillary glial cells in the retina and vitreous, severe atrophy of the optic nerves, and degenerative hyalinization of blood vessels. This case is the first published report of the histopathology of the inner ear in Norrie's disease.

Aged↗
PubMedDate not supplied

The hip in Stickler syndrome.

Stickler syndrome is an autosomal dominant connective tissue disorder with a prevalence similar to that of Marfan syndrome. No previous study has examined hip pain or abnormalities in a large series of patients with Stickler syndrome. The purpose of this study was to describe hip abnormalities and their correlation with age and chronic hip pain in a cohort of 51 patients followed at the National Institutes of Health. Ten percent of patients had protrusio acetabuli, 21% coxa valga, and 34% of adults had hip osteoarthritis. Sixty-three percent of all patients and 79% of adults had chronic hip pain. In addition, 16% of adult patients had a history of femoral head failure during youth. Arthritic changes and adult age were associated with hip pain. In summary, hip abnormalities are commonly observed in Stickler syndrome. Young patients require careful evaluation of hip pain, and regular screening of children with Stickler syndrome may be indicated for early detection of hip complications.

Abnormalities, Multiple↗