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Biomedical subjects

A Daniel

Publications and source records attributed to A Daniel.

At least 55 records · Page 3Linked to original sources
PubMed1989

Risks of unbalanced progeny at amniocentesis to carriers of chromosome rearrangements: data from United States and Canadian laboratories.

Data on 1,237 prenatal (amniocyte) diagnoses in cases of familial chromosome rearrangements were collated from 79 American and Canadian laboratories. These were added to European data (Daniel et al: Prenatal Diagn 6:315-350, 1986) on 596 reciprocal translocations (rcp) from 71 collaborative laboratories. The total data set was examined for relationships between balanced or unbalanced result and mode of ascertainment, sex of carrier parent, chromosomes involved, and (in cases of reciprocal translocations and pericentric inversions) for potential or actual chromosome imbalance size (% haploid autosome length). Risk rates for unbalanced segregants were markedly dissimilar. These ranged from approximately 50% down to essentially a negligible risk. The risk was approximately 50% for carriers of the following: complex chromosome rearrangements (ccr); insertions (ins); and for 2:2 segregating rcp ascertained by mode 1 (term unbalanced proband) with small imbalance segments. Pooled carriers (either sex) of 2:2 segregating rcp of mode 1 had a risk of 20-25% whereas female Robertsonian (rob) translocation (D;21) carriers and pericentric inversion (pii) carriers of pii with small distal segments had a risk of 10-15%. Pooled 2:2 segregating rcp carriers ascertained by mode 2 (a couple with recurrent miscarriages) and male carriers of rob (D;21) had a risk of 1.5-5%. The risk of unbalanced segregants was 1-2% (in this data) for male and female rob (13;14) carriers and for pooled pericentric inversion carriers. However, for carriers of most "type" (recurrent breakpoints) pii, for all paracentric inversions, and (as expected) for rob not involving 13 or 21, there were no term unbalanced progeny. For 2:2 segregating reciprocal translocations plots were prepared that could be used to determine broad risk groups for carriers of such rcp. In 3:1 segregating rcp there were 3.3 times fewer male than female carriers, whereas there were 1.3 times fewer male carriers in 2:2 segregating rcp. In 2:2 segregating rcp there is little effect on the fertility of male carriers and risks of unbalanced progeny were found to be equal to those for female carriers, whereas in the 3:1 segregating rcp, risks were much less for male as compared to female carriers. This indicates that 3:1 segregating rep are more similar to Robertsonian translocations in their greater effect on the fertility of male carriers.(ABSTRACT TRUNCATED AT 400 WORDS)

Abortion, Habitual↗
PubMed1989

Treatment of a periodontal intrabony pocket in man by a mucoperiosteal free graft combined with a calcium phosphate implant.

A two-walled intrabony pocket was treated by a mucoperiosteal free graft interposed between the curetted root surface and a calcium phosphate implant. The eighteen months follow up radiography showed complete healing of the bone defect, a normal periodontal ligament space, an uninterrupted lamina dura and a well-formed septum. The use of mucoperiosteal free graft may supply the wounded area with different cells such as fibroblasts, undifferentiated mesenchymal cells, periosteal cells, intercellular fibers and biochemical substances such as glucosaminoglycans, proteoglycans etc...

Adult↗
PubMed1988

Theoretical bases for karyotype evolution. II. The fusion burst in man and mouse.

As a theoretical standard for evaluating the high incidence of centric fusion in man and mouse, the relative probabilities of occurrence of reciprocal translocation (Tr), inversion (In) and centric fusion (Fu) were estimated based on the random-contact-and-exchange model. It was shown by this model that centric fusion was extremely rare (Fu = 0.0002, In = 0.0521 and Tr = 0.9477 for a human haploid karyotype). On the other hand, the occurrence rate of centric fusion in human newborn babies and European feral mice was about 500-1,000 times higher than the theoretically expected values, which is termed here the "fusion burst". We suggest that the fusion burst may be induced by the physical proximity of telomeres on the nuclear membrane, and the exchange of DNA strands by errors of telomere replication mechanisms. The cytogenetical significance of the fusion burst is discussed with regard to the minimum interaction hypothesis proposed by Imai et al. (1986). We suggest two closely linked possibilities that (1) the fusion burst in man and mouse can theoretically be placed in karyotype evolution as a transitional phase in the main stream of the fission-inversion cycle, and (2) it may be accelerated by some unknown (mutagenic) factors other than ionizing radiation.

Animals↗
PubMed1987

H-Y typing by ELISA in a 46,X,dic(Y)(q11.2101) male: effects of a nonmosaic Yp duplication.

A new ELISA was used to measure H-Y antigen in cultured fibroblasts from a male with 46,X,dic(Y)(q11.2101) involving duplication of Yp. Aliquots of monoclonal H-Y antibody were absorbed with 1, 2, 4, or 8 X 10(6) cells from the 46,X,dic(Y) male, or with corresponding numbers of cells from a normal XY male and a normal XX female, and then were tested for residual activity against a soluble antigen source. Portions of the antibody absorbed with cells of the 46,X,dic(Y) male were found to be less reactive than portions absorbed with cells of the normal XY male, for all numbers of cells and both dilutions of plated antigen. The results, quantified in an electronic optical density reader, imply presence of excessive H-Y in cells of the 46,X,dic(Y) male, and suggest presence of a genetic determinant of H-Y on Yp or proximal Yq near the centromere.

Antibodies, Monoclonal↗
PubMed1987

Isochromosome 12p mosaicism (Pallister mosaic aneuploidy or Pallister-Killian syndrome): report of 11 cases.

We report on 11 cases of isochromosome 12p mosaicism (or Pallister mosaic aneuploidy syndrome) in which the isochromosome is usually absent in cultured lymphocytes but present in fibroblasts. The patients range in age from a 22-week-gestation fetus to a 45-year-old man. They have a distinct pattern of anomalies which enables one to make a diagnosis based on clinical manifestations alone. Craniofacial manifestations include "coarse" face with prominent forehead, sparsity of scalp hair, hypertelorism, epicanthal folds, flat bridge of nose, and highly arched palate. Affected newborn infants are profoundly hypotonic with sparsity of scalp hair especially bitemporally and a prominent forehead. Most have accessory nipples. Birthweight and growth parameters are usually normal; however, some newborn infants are unusually large. In infancy, the facial appearance becomes "coarse," hypotonia persists, and seizures may occur. As adults, growth may be normal, scalp hair is thicker and the mandible becomes prominent. Most have a generalized pigmentary dysplasia which may be evident with a Wood's lamp only. All cases have been sporadic and there is no consistent pattern of advanced parental age.

Abnormalities, Multiple↗
PubMed1987

Atypical phenotype associated with deletion (15) (pter----q11::q13----qter).

We report on a 10-year-old boy with an interstitial deletion within the region of bands 15q11----q13. Authors have associated the manifestation of the Prader-Willi syndrome (PWS) with variable deletions involving the bands q11----q13. Our patient had atypical manifestations not usually associated with PWS, ie, normal stature, proportionally sized hands and feet, normal genitalia, and was nonambulatory and severely mentally retarded. This case emphasized the clinical diversity seen in proximal 15q deletions in the region considered to be correlated with the PWS.

Child↗
PubMed1987

The Montana Fetal Genetic Pathology Program and a review of prenatal death in humans.

Western medicine is being sensitized to the enormous extent of prenatal death in humans at a time when such deaths, occurring after the first missed period, involve to an ever increasing degree wanted pregnancies conceived by women with rising mean maternal age, decreasing mean fertility, and ever greater desire and intention to assure a good pregnancy outcome. Available data suggest that about two-thirds of human ova, embryos, and fetuses fail to reach birth or the end of the first year of life, with infant mortality of 1.06%, stillbirth rate of 8/1,000, abortion rate of about 15%, and death rate around the time of implantation estimated at 34%. Based on limited data on sperm, ova aspirated from Graafian follicles in infertile women, direct observation of a few implanting ova, the low rate of human fecundity, and the high failure rate of in vitro fertilization, it seems reasonable to suppose that about 30% of human ova perish at the time of fertilization and before implantation. Most of this prenatal death is attributable to chromosome abnormalities (aneuploidy and polyploidy), estimated to be present at the beginning of development in about half of all human ova or embryos. Parent's anguish about prenatal death and their desire to understand its causes and to prevent recurrence is putting the medical profession under severe pressure to provide diagnostic and counseling services and make available prenatal diagnosis and preventive approaches; this comes at a low point in the ability of Western medicine to respond adequately, especially in the fields of embryology and developmental genetics, clinical teratology, anatomical pathology, and genetic pathology. Unless drastic ameliorative measures are taken, the situation is likely to get much worse, since health insurance pays for only a minute fraction of costs involved and the number of pediatric pathologists devoting major effort to this work in North America has dwindled to a small number without great hope for replacement from younger ranks, primarily as a result of the lack of incentive by the tertiary centers to make fetal genetic pathology ("morphology") an attractive field to work in. Here we report an effort by a secondary care center to provide such a service--presently more on demand than as systematic effort to reach all at need--in a huge, underpopulated state with birthrate of less than 13,000 and lacking any specially trained pathologist with a strong interest in the field.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

Comparison of cytologic and genetic distances between long arm subtelomeric markers of human autosome 14 suggests uneven distribution of crossing-over.

The analysis of two rodent X human somatic cell hybrids, carrying different inborn translocations of the human chromosome 14 long arm, has permitted us to narrow down the localization of the structural locus for alpha-1-antitrypsin (PI) to band 14q32.1, proximally to the highly polymorphic DNA locus D14S1 which has been localized by previous studies between 14q32.1 and 14q32.2. These data, evaluated in conjunction with other published information, suggest that the D14S1 locus is cytologically equidistant from both the PI locus and the complex locus for the immunoglobulin heavy chains (IGH) but, genetically, it appears much closer to the latter since the recombination frequency reported between the IGH complex and PI is six times greater than that between the IGH complex and D14S1 (lod score peaks respectively at 26% and 4% with narrow fiducial limits). The present report adds further strength to the frequently proposed hypothesis of a nonlinear relationship between cytologic and genetic distances of human genes. The possibility that this phenomenon may be a feature of frequent occurrence throughout the entire human genome is discussed.

Animals↗
PubMed1987

Aneuploidy is not induced by ethanol during spermatogenesis in the Chinese hamster.

Aneuploidy was scored in spermatogonial stages and at both meiotic divisions in male Chinese hamsters exposed to alcohol in vivo. After light ether anesthetization, the animals were intubated (by gastric tube) with 1.5 ml of 12.5% ethanol, whereas controls were given 1.5 ml of distilled water. Gonadectomy was performed 3.5-24 h after ethanol exposure. Ethanol-dosed animals were obviously intoxicated, as evidenced by a rolling gait; serum alcohol levels in 10 animals that were tested peaked 1-2 h after exposure. Among the animals exposed to ethanol, no significant difference over time in the rates of aneuploidy was observed. These data were pooled, and, when compared to control rates, no significant difference could be attributed to ethanol exposure. The aneuploidy found could therefore be interpreted as background rates, and these compared well with data previously published for the Chinese hamster. Several artifactual phenomena were observed: Up to 15% aneuploid spermatogonial metaphases were seen in test and control animals. These were attributed to the mechanical breaking-up of closely apposed groups of diploid spermatogonia. Significant numbers of artifactual diploid MII figures and hypohaploid MI and MII figures were also recorded. To address the possibility that a spermatogonial or other long-term effect could be detected, two animals (with controls) were dosed with 12.5% ethanol daily for 13 and 16 days before sacrifice. No aneuploidy attributable to ethanol was found at MII in these animals either.

Aneuploidy↗
PubMed1987

Creatine and density of red blood cells in perinatal hypoxia.

Signs of stimulated erythropoiesis, such as increased creatine and decreased density of red cells are good indicators of hypoxemia in adults and older children. The sensitivity of both tests in perinatal hypoxia was found to be reduced. The causes for this reduction were investigated.

Animals↗
PubMed1987

Ellis-van Creveld syndrome in Kerala.

A case of the Ellis-van Creveld syndrome is described. Emphasis is laid on the probable relation to the frequency of consanguineous marriages among the Hindu community in Kerala.

Child, Preschool↗