Inhibition by puromycin of incorporation of tritiated uridine into nucleolar and cytoplasmic ribonucleic acids.
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Cell Nucleolus↗
Biomedical subjects
L G Jackson
Publications and source records attributed to L G Jackson.
Chemotherapy in ovarian malignancy: tumor sensitivity testing.
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Antineoplastic Agents↗
New X-linked mental retardation disorder with Dandy-Walker malformation, basal ganglia disease, and seizures.
We report on a 4 generation family of individuals with an X-linked form of mental retardation involving 9 affected males and 5 obligate carrier females. Key manifestations include severe mental retardation, early hypotonia with progression to spasticity and contractures, choreoathetosis, seizures, presence of a long, narrow face with coarse features, cystic enlargement of the fourth ventricle with cerebellar hypoplasia (Dandy-Walker malformation), and iron accumulation in the basal ganglia with neuroaxonal dystrophy similar to Hallervorden-Spatz disease. Of the 5 known heterozygotes, 3 are dull intellectually, and one of the 3 developed a "presenile dementia." At autopsy she had iron deposition and neuroaxonal dystrophy in the basal ganglia and atrophy of the cerebral cortex. Although the clinical findings among relatives are variable, we conclude that this is a distinct, previously unrecognized X-linked mental retardation syndrome.
Abnormalities, Multiple↗
First trimester diagnosis of Lesch-Nyhan syndrome: applications to other disorders of purine metabolism.
The prenatal detection of hypoxanthine phosphoribosyltransferase (HPRT, EC 2.4.2.8) deficiency, the Lesch-Nyhan syndrome, during the first trimester of an affected pregnancy through the use of chorionic villus sampling is reported. Quantitation of reaction products formed by villus cell extracts from exogenous hypoxanthine-8-[14C] or adenine-8-[14C] is used in diagnosis. We report the diagnosis of Lesch-Nyhan syndrome using a chorionic villus specimen and confirmation of that diagnosis. In addition, adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP), enzymes deficient in inherited immune disorders, are detected in chorionic villus samples. These heritable disorders also appear amenable to early prenatal diagnosis.
Adenine↗
Prenatal diagnosis for Tay-Sachs disease using chorionic villus sampling.
Prenatal diagnosis for Tay-Sachs disease was performed on 25 patients using chorionic villus sampling (CVS). Nineteen were diagnosed as normal, and six were affected. Normal villus extracts had both hexosaminidase (hex) A and B activity, as determined by Cellogel and polyacrylamide gel electrophoresis, while extracts from affected fetuses had only hex B activity. Compared to cultured amniotic fluid cells or fibroblasts, villi contained less hex A. Hex A levels in fresh villi and cultured trophoblasts were roughly comparable.
Amniotic Fluid↗
Prenatal diagnostic techniques. Chorionic villus sampling.
Chorionic villus sampling (CVS) is a new prenatal diagnostic technique which is performed in the first trimester of pregnancy. Traditional methods of prenatal diagnosis, including amniocentesis and fetoscopy, must be performed in the midtrimester. In concert with the development of DNA methods of fetal cell analysis, first trimester fetal diagnosis utilizing CVS offers many advantages over traditional mid-trimester techniques. In addition, CVS may potentially allow therapeutic intervention to prevent or ameliorate some congenital defects.
Amniocentesis↗
Molecular evidence for new mutation at the hprt locus in Lesch-Nyhan patients.
Hypoxanthine-guanine phosphoribosyltransferase (HPRT; EC2.4.2.8), which functions in the metabolic salvage of purines, is encoded by an X-linked gene in man. Partial HPRT deficiencies are associated with gouty arthritis, while absence of activity results in Lesch-Nyhan syndrome (L-N). L-N patients fail to reproduce and the heterozygous state appears to confer no selective advantage. Thus, Haldane's principle predicts that new mutations at the hprt locus must occur frequently in order for L-N syndrome to be maintained in the population. This constant introduction of new mutations would be expected to result in a heterogeneous collection of genetic lesions, some of which may be novel. As we report here, the mutations in the hprt gene of seven L-N patients, selected from an initial survey of 28 patients, have been characterized and all were found to be distinctly different, as predicted. The origin of one unusual mutation has been identified by analysis of DNA from four generations of family members. Further molecular analysis of the origin of new mutations at the hprt locus should aid in resolving the issue of an apparent difference in the frequency of hprt mutations in males and females.
DNA Restriction Enzymes↗
Cell surface antigen expression of first trimester chorionic villus samples.
First trimester chorionic villi obtained by chorionic villus sampling at approximately 9 weeks of gestation were investigated by indirect immunofluorescence to demonstrate trophoblast cell surface antigen expression. Villous trophoblast expressing the trophoblast specific markers transferrin receptor, human placental lactogen, and cytokeratin was also found to express a monomorphic major histocompatibility complex class I determinant recognized by the monoclonal antibody W6/32. W6/32 positive regions included sparsely scattered regions of villous trophoblast and fanning outgrowths of trophoblast. The class I antigenic determinant expressed by first trimester trophoblast was found to be recognized exclusively by W6/32 when assayed with a panel of anti-class I determinant monoclonal antibodies. Trophoblast W6/32 determinant expression was not increased after 24 hour organ culture in the presence of 200 U of interferon gamma. Exposure to interferon gamma resulted in increased class I antigen expression by mesenchyme and low level de novo mesenchyme class II antigen expression. These data suggest that early gestational stage villous trophoblast express non-classical class I antigens which do not seem to be subject to the regulatory effects of interferon gamma.
Antigens, Surface↗
Ophthalmologic findings in the Cornelia de Lange syndrome.
Cornelia de Lange Syndrome (CDLS) is characterized by mental retardation, growth retardation, skeletal anomalies, and a characteristic facies. We examined 22 children with CDLS to ascertain the relative frequencies of oculofacial and ophthalmologic abnormalities. We confirm prior reports of the frequent findings of brow hypertrichosis, synophrys, and long arcuate eyelashes. In addition we documented the association with ptosis, nystagmus, and high myopia. Contrary to previous reports, we did not find blue sclera or corneal, pupillary, or retinal disorders to be part of this syndrome. Hypertelorism and telecanthus were found, but they were dependent on the method of calculation. Two children had optic nerve pallor. We also report the new findings of poor macular reflex, chin lifts induced by ptosis, hypertropia, and nasolacrimal duct fistula.
Adolescent↗
Extra structurally abnormal chromosomes (ESACs)--presentation of 10 new cases.
BACKGROUND: The goal of the presented studies as a retrospective reliability assessment of classical banding cytogenetic studies and of prognosing epicrises in a group of 14 cases, affected with additional marker chromosomes. MATERIAL AND METHODS: Having collected the study material from peripheral blood, by means of trophoblast biopsy or amniocentesis, cytogenetic preparations were obtained, allowing for pre- or postnatal evaluation of the karyotype. A panel of auxiliary cytogenetic techniques accompanied the routine CTG protocol. RESULTS: In a group of 6875 persons with recommendations to pre- or postnatal cytogenetic diagnostics, 14 (0.2%) cases of ESACs were diagnosed. In 5 cases of DA/DAPI(+) inv dup (15) as observed. A presence of polymorphic interstitial RHG(+) band was found within the marker chromosome. The measured size of that band allowed associating it with either the presence or the absence of pathological signs. In 9 cases of ESACs, DA/DAPI(-), the application of banding techniques (NOR and CBG) allowed to discover bisatellite heterochromatic ESACs in 6 cases (2 non-mosaic and 4 mosaic). In three other mosaic and non-satellite cases of ESACs, a 'genetic inactivity' of the marker chromosome was observed in one case, while a 'genetic activity' was ascertained in two cases. The 'activity' of marker chromosomes was studied by means of replication banding techniques. CONCLUSIONS: At the time of the outburst of molecular techniques, still up-to-date is the use of classical banding techniques and of the replication techniques, allowing DNA replication kinetics studies at the level of single band.
Adolescent↗
Prenatal diagnosis of neurolipidoses.
While there is no single best procedure for performing prenatal diagnosis, ther is a rationale or strategy which will produce correct, reliable results. The investigator should be experienced with all the tests and know what to expect from each. At least two of these tests should e used (more if there s ambiguity) on amniotic fluid and cultured cell extracts. Which tests, and how many, are not as important as the skill and experience of the investigator performing them. Proper controls should be used. Probably the biggest single factor in successful prenatal diagnosis is the use of both negative and positive controls run simultaneously. No method, no matter how good or how well performed, can be counted upon to give sufficiently reproducible results to interpret without these controls. Finally, it is necessary for the investigator to be thoroughly familiar with the enzyme and its isozymes and the clinical heterogeneity of the disease. Although the foregoing details pertain specifically to Tay-Sachs disease, similar or related problems exist in the prenatal diagnosis of any of the neurolipidoses. The need for care of the samples, appreciation of biochemical and clinical heterogeneity, the need for adequate techniques, and the importance of proper controls are requirements for diagnosing any of the neurolipidoses.
Amniotic Fluid↗