bluuebunny/crossref_metadata_2025 huggingface dataset:
Karyological analysis of Rous sarcoma virus-producing rat-kangaroo cell lines
Authors: Donner L. , Sainerová H. , Svoboda J.
Published: May 2008

Karyological analysis of the PtK 1 cell line and of cell lines derived from it which had been productively infected with Rous sarcoma virus (Schmidt-Ruppin strain) revealed heterogeneity among the various stemlines. The 11-chromosome stemlines of all cell lines were composed of several karyotypic variants. The frequency of chromosomal damage in the Rous sarcoma virus-producing cell lines was not increased above the control level in the noninfected cell line.
Chromosomal breakage in leukocytes of South American Indians
Authors: Bloom A.D. , Neel J.V. , Tsuchimoto T. , Meilinger Karen
Published: May 2008

Cytogenetic studies were performed in 1969, 1970, and 1971 on the Yanomama and Piaroa Indians of Venezuela. The early studies involved 49 Yanomama, of whom 13 had 23 cells with extensive chromosome breakage and rearrangement, so-called complex cells. The virtual disappearance of these complex cells in subsequent studies of the Yanomama was accompanied by a decline in the percentage of cells with any aberration, from 4.2 in 1969, to 2.6 in 1970, to 1.4 in 1971. This progressive decrease in abnormalities may bethe result of the elimination of chromosomally damaged cells after exposure to a chromosome-breaking agent.
G-group chromosomes in satellite associations
Authors: Nakagome Y.
Published: May 2008

G-group chromosomes involved in satellite associations were identified by the technique of G-banding. Metaphases were obtained from nine normal individuals. Out of a total of 537 G-group chromosomes, 297 were No. 21s and 240 were No. 22s. There seemed to be a slight but consistent excess of No. 21 chromosomes in satellite associations.
Karyotype of the chimpanzee, Pan troglodytes, based on measurements and banding pattern: comparison to the human karyotype
Authors: Warburton Dorothy , Firschein I.L. , Miller Dorothy A. , Warburton F.E.
Published: May 2008

A standard nomenclature for chimpanzee chromosomes is proposed, based on banding patterns and measurements. Comparison of chromosome lengths suggests that the total amount of chromosome material is approximately the same in the human and chimpanzee. Correlation of banding patterns and measurements confirm that the chromosomes of the two species differ by rearrangement of heterochromatic material, several pericentric inversions, and at least one translocation.
Meiotic disjunction in T(14;15)6Ca heterozygotes and fate of chromosomally unbalanced gametes in embryonic development
Authors: Oshimura M. , Takagi N.
Published: May 2008

In heterozygous carriers of the mouse reciprocal translocation T(14;15)6Ca, the frequency of nondisjunction involving the minute marker chromosome was 4.4 % in the male and 22.2 % in the female. The fate of gametes with unbalanced genomes derived from normal as well as abnormal meiotic disjunction in T6 heterozygotes was investigated on the basis of chromosome counts at metaphase II and karyotype analyses in early postimplantation embryos produced by backcrossing with chromosomally normal animals. Results obtained indicate that meiotic, gametic, and zygotic selection attributable to specific types of chromosomal imbalances is minimal, if any, by the late blastocyst stage. All zygotes with unbalanced genomes, except those with 20 normal pairs plus the minute marker, however, die off in the latter half of pregnancy. Therefore, the increased incidence of translocation trisomics among progeny of female as compared with male heterozygotes reflects the higher incidence of nondisjunction in primary oocytes than in spermatocytes.
Karyotype of the gibbons Hylobates lar and H. moloch: Inversion in chromosome 7
Authors: Tantravahi R. , Dev V.G. , Firschein I.L. , Miller D.A. , Miller O.J.
Published: May 2008

A karyotype of the gibbon, Hylobates, has been prepared based on the chromosome banding patterns produced by quinacrine, trypsin-Giemsa, and centromeric heterochromatin stains. The banding patterns of H. lar and H. moloch are virtually identical. No brilliant quinacrine-fluorescent areas are present. The banding pattern of most of the gibbon chromosomes show less resemblance to those of the human, chimpanzee, gorilla, or orangutan than the chromosomes of the higher primates do to each other, suggesting a relatively large evolutionary separation of the gibbon from the higher primates. A pericentric inversion of chromosome 7 is present in one gibbon.
Triploidy and haploid-triploid mosaicism among chick embryos (Gallus domesticus)
Authors: Zartman D.L. , Smith A.L.
Published: May 2008

Homomorphic, chromosomally abnormal roosters were mated to normal hens. The 23 hens produced 67 embryos, including two triploids and a haploid-triploid mosaic at about 26 hours of incubation. Both of the triploid embryos were conceived within a 5-day period. The presence of a single genome of paternal origin with marker chromosomes in each triploid led to the conclusion that these embryos were derived from diploid, ZW-type ova fertilized by haploid, Z-type spermatozoa. The inheritance pattern of the mosaic embryo was clearly due to a spermatozoal origin for the haploid cell line; and one genome of the three in the triploid cell line was paternal. The sex chromosomes were Z/ZZZ, with one Z of each cell line being a translocation product of paternal derivation.
DNA replication patterns of human chromosomes from fibroblasts and amniotic fluid cells revealed by a Giemsa staining technique
Authors: Epplen J.T. , Siebers J.-W. , Vogel W.
Published: May 2008

A technique is described for visualizing late-replicating regions by a Hoechst 33258-Giemsa-staining procedure combining the techniques of Latt (1973) and of Perry and Wolff (1974). The advantages are two-fold: distinct bands are obtained and many possible mistakes and interpretation difficulties with autoradiography are avoided. The time sequence of late-replication patterns (excepting C-group chromosomes) has been established in human fibroblasts of adults, and these results have been compared with three of four different cell types from amniotic fluid. No significant differences in late-replication patterns and time sequence of the different cells could be discovered. As expected, the replication patterns are in good concordance with the patterns of G- and Q-bands. Some exceptions are described.
Mitotic association patterns of nucleolar organizing chromosomes in the mouse
Authors: Spence M.A. , Luthardt F.W.
Published: May 2008

Following the report of localization of nucleolar organizer regions to chromosome pairs 15, 18, and 19 of the mouse, a study was undertaken to test these chromosomes for association during mitotic metaphase. Cells from seven strains of mice were analyzed, and no strong evidence was found for any significant association patterns.
The interrelationships of chromosome banding patterns in procyonids, viverrids, and felids
Authors: Wurster-Hill D.H. , Gray C.W.
Published: May 2008

The Giemsa banding patterns of the chromosomes of 4 species of Procyonidae, 13 of Viverridae, and 6 of Felidae have been studied. The patterns have all been related to the basic felid karyotype. Each procyonid and viverrid has a distinctive karyotype, whereas some felids have indistinguishable karyotypes even when banded. Extensive interfamilial G-banding conservatism has been demonstrated, with many chromosomes being “shared” by all three families. A chromosome identification and karyotyping system for the Carnivora has been devised to facilitate comparison of data from future studies. Phylogenetic implications of the findings have been discussed.
The Giemsa banding pattern of the canine karyotype
Authors: Selden J.R. , Moorhead P.S. , Oehlert M.L. , Patterson D.F.
Published: May 2008

The canine metaphase karyotype consists of 78 chromosomes. All autosomes exhibit telocentric or acrocentric configurations gradually diminishing in size. These features make identification of homologous pairs by conventional analysis difficult.Chromosome preparations were derived from short-term cultures of peripheral blood lymphocytes obtained from clinically normal dogs representing at least four breeds. Most components of the canine karyotype can be distinguished readily. No significant G-banding pattern variations were detected in the individuals screened. An idiogrammatic interpretation of the banding pattern is presented. Apart from bands, other characteristic morphologic features were found which aid in identification. The G-banding pattern of the canine metacentric X is quite similar to that of the banded human X. The canine Y is a minute metacentric having two positive bands.
European experience with prenatal diagnosis of congenital disease: a survey of 6121 cases
Authors: Galjaard H.
Published: May 2008

The results of 6121 prenatal diagnoses established by 46 centers in eight West-European countries are reported. The percentage of “spontaneous” abortions following early amniocentesis (1.4 %) does not seem to exceed the normal rate of spontaneous abortion in this period of pregnancy. A total of nearly 300 affected fetuses was detected, and in all but 5 instances the parents asked for interruption of the pregnancy. The majority of prenatal monitoring (75 %) was carried out because of an increased risk of chromosomal aberration. In the group with higher maternal age, 2.8 % of the fetuses were affected; this figure was 4.6 % for mothers older than 38 years. Monitoring because of an earlier child with trisomy 21 showed 1.3 % fetuses with a chromosomal aberration, and 1.7 % abnormal karyotypes were detected in the group where amniocentesis was performed for “miscellaneous reasons.” In pregnancies where a parental translocation had been demonstrated, 6.7 % of the fetuses showed an unbalanced karyotype and 25 % were balanced carriers. Also discussed are results and organizational problems of prenatal monitoring for inherited metabolic disorders (206 analyses for 23 different enzyme defects) and for neural tube defects (about 2700 cases).
Does the T-locus in the mouse include ribosomal DNA?
Authors: Atwood K.C. , Gluecksohn-Waelsch S. , Yu M.T. , Henderson A.S.
Published: May 2008

The proportion of rDNA in the mouse genome is shown to have no systematic relation to the T-locus genotype, and hybridization in situ with 125I-rRNA does not label chromosome 17, which carries the T-locus. Thus rDNA need no longer be taken into account in explaining the unique properties of the alleles at this locus. The number of genes for rRNA precursor averaged 150 per haploid genome, but a large measure of individual variation is suggested.
The in vitro isolation and characterization of monosomic sublines derived from a Colcemid-treated Chinese hamster cell population
Authors: Cox D.M. , Birnie S. , Tucker D.N.
Published: May 2008

A series of 18 sublines deficient for one or two chromosomes was isolated in vitro from a pseudodiploid Chinese hamster cell population treated appropriately with Colcemid to obtain maximal induction of aneuploidy. Chromosomes 10 and 11 were the most frequently involved and, to a lesser extent, chromosome 9 and the partially deleted 6. Since analysis of chromosome banding patterns did not reveal any evidence of chromosome rearrangement, it was concluded that entire chromosomes were absent, and thus the sublines are presumed to be monosomic. The monosomic state was quickly lost during serial culture, and by the 15th passage after isolation, the monosomic cell type accounted for less than 50 % of the cell population in over half of the sublines. This was due either to a shift in chromosome number back to 22, apparently by reacquisition of the absent chromosome, or to the appearance of tetraploidy.
Spontaneous triploidy in the California roach Hesperoleucus symmetricus (Pisces: Cyprinidae)
Authors: Gold J.R. , Avise J.C.
Published: May 2008

A single triploid individual (3n = 75) of the California roach, Hesperoleucus symmetricus, was identified among a sample of nine specimens from the Russian River, California. The diploid number of H. symmetricus, as revealed by the karyotypes of the remaining eight specimens, is 50. Aside from the all-female triploid unisexual fishes, this is the first report of a triploid fish from the wild, and the second report of a triploid in a bisexual fish species. The most likely origin of the triploid was probably fusion of a haploid sperm with an unreduced ovum.
Fluorescent (F) bodies in the spermatozoa of man and the great apes
Authors: Seuánez H. , Robinson J. , Martin D.E. , Short R.V.
Published: May 2008

Mature spermatozoa of the chimpanzee (Pan troglodytes), the gorilla (Gorilla gorilla), and the orangutan (Pongo pygmaeus) were stained with quinacrine dihydrochloride. Fluorescent (F) bodies were visualized in the spermatozoa of the chimpanzee and gorilla but were absent in the orangutan, in which there is no brilliant fluorescence in any chromosome. The F bodies appeared to be randomly located in the sperm heads of these two species, as they usually are in human spermatozoa. However, the proportion of sperm showing one or more F bodies in the chimpanzee and gorilla was not comparable to what is usually found in man. The F bodies in the chimpanzee presumably represent brilliant regions in the autosomes, since the Y chromosome has no brilliant fluorescence in this species. This is contrary to man, in which the F body is an useful indicator of the Y chromosome. In the gorilla, the F bodies probably correspond to both the Y chromosome and to some brilliant regions in the autosomes.
Cytogenetic examination of pre-implantation blastocysts of ewes mated to rams heterozygous for the Massey I (t1) translocation
Authors: Long S.E.
Published: May 2008

One hundred-and-two 13- to 18-day blastocysts were collected from 98 Scottish Blackface ewes mated to one of four New Zealand Romney rams heterozygous for the Massey I (t1) translocation. The karyotype of 75 blastocysts was established, of which 22 were 54, XY, 18 were 54, XX, 20 were 53, XY, t1, and 15 were 53, XX, tι. It is suggested that these results indicated that there was no increase in embryonic loss in ewes mated to rams heterozygous for the Massey I (t1 translocation and that the unbalanced secondary spermatocytes in heterozygous males probably did not mature to spermatozoa.
DNA replication in the sex chromosomes of the pronghorn and the Rocky Mountain goat
Authors: Dain A.
Published: May 2008

The X chromosome of the male pronghorn (Antilocapra americana) is larger than the “original” type and carries a large segment of late-labelling chromatin. The Y chromosome has a late-labelling segment that appears to duplicate synchronously with that of the X. Both chromosomes have segments that label throughout the period of observation; that of the X is about 4.7 % of the haploid complement and approaches “original” proportions. The X chromosomes of the Rocky Mountain goat (Oreamnos americanus) appear to be of the “original” type, without marked late-labelling regions, and the Y chromosome is small. The structure and origin of extra-large sex chromosomes are discussed.
A simplified technique for in vivo analysis of sister-chromatid exchanges using 5-bromodeoxyuridine tablets
Authors: Allen J.W. , Shuler C.F. , Mendes R.W. , Latt S.A.
Published: May 2008

A small tablet of 5-bromodeoxyuridine (BrdU), implanted subcutaneously in a mouse, provides sustained release of base analog sufficient to effect substitution of DNA throughout an entire replication period. As illustrated by studies of mouse bone-marrow and spleen cells in the presence or absence of cyclophosphamide, this depot method of BrdU administration greatly simplifies in vivo analysis of sister-chromatid-exchange formation.
Regional assignment of seven genes on chromosome 1 of man by use of man-Chinese hamster somatic cell hybrids
Authors: Jongsma A.P.M. , Burgerhout W.G.
Published: May 2008

Regional localization studies of genes coding for human PGD, PPH1, PGM1, UGPP, GuK1, Pep-C, and FH, which have been assigned to chromosome 1, were performed with man-Chinese hamster somatic cell hybrids. Informative hybrids that retained fragments of the human chromosome 1 were produced by fusion of hamster cells with human cells carrying reciprocal translocations involving chromosome 1. Analysis of the hybrids that retained one of the translocation chromosomes or de novo rearrangements involving the human 1 revealed the following gene positions: PGD and PPH1in 1pter→1p32, PGM1in 1p32→1p22, UGPP and GuK1in 1q21→1q42, FH in 1qter→142, and Pep-C probably in 1q42.
A new approach to quantitative analysis of somatic association
Authors: Lacadena J.-R. , Ferrer E. , Yañez I.
Published: May 2008

A formula is proposed for estimating statistically the degree of somatic chromosome association during metaphase. Standard chi-square tests can then be used to determine the presence or absence of somatic association between homologous chromosomes in selected species. The method requires that the chromosomes be morphologically distinguishable and that their circular arrangement on the metaphase plate has not been distorted by the squash used during their preparation.
Synteny of the genes for thymidine kinase and galactokinase in the mouse and their assignment to mouse chromosome 11
Authors: McBreen P. , Orkwiszewski K.G. , Chern C.J. , Mellman W.J. , Croce C.M.
Published: May 2008

We have studied the expression of mouse galactokinase in human-mouse somatic cell hybrids segregating mouse chromosomes. Since concordant segregation of the expression of mouse galactokinase and the presence of mouse chromosome 11 were observed in the hybrid clones, we conclude that the gene for mouse galactokinase is located on mouse chromosome 11. We have also investigated the expression of mouse galactokinase in somatic cell hybrids between thymidine kinase-deficient Chinese hamster cells and mouse peritoneal macrophages. The results of this study indicate that the expression of mouse galactokinase and thymidine kinase segregates concordantly, and, therefore, we infer that the gene for mouse thymidine kinase is also located on mouse chromosome 11.
Chromosomes of Peromyscus (Rodentia, Cricetidae)
Authors: Deaven L.L. , Vidal-Rioja L. , Jett J.H. , Hsu T.C.
Published: May 2008

In the genus Peromyscus cells of all species contain 48 chromosomes; however, the fundamental number varies from 56 (P. crinitus, P. boylei) to 96 (P. eremicus). In some cases biarmed chromosomes are the result of pericentric inversions, while in others they are the result of addition of large amounts of constitutive heterochromatin. Flow microfluorometric DNA-per-cell determinations demonstrated that in some species (P. eremicus) the genome is increased by 36 % over the amount of DNA found in most mammalian species. Studies of unique karyotypes with increased amounts of DNA added as constitutive heterochromatin may ultimately help in the elucidation of the mechanisms involved in karyotype evolution and speciation.
Karyologic studies on hybrids between Asian, Ceylonese, and Oceanian type black rats, with a note on an XO female occurring in the F2 generation
Authors: Yosida T.H.
Published: May 2008

F1 hybrids between the Asian type (2n = 42) and Ceylonese type black rats (2n = 40) invariably showed 41 chromosomes, while those between the Oceanian type (2n = 38) and the Ceylonese type usually showed 39 chromosomes. Twelve F2 hybrids (three litters) were obtained only from the latter combination. Among them, the karyotypes of nine rats were successfully analyzed. They were segregated into the Oceanian type (three rats) and the F1 type (six rats). No Ceylonese type was obtained. From the results of fertility testing in F1 hybrids between these three variants, the Oceanian type is assumed to be more closely related to the Ceylonese type than the Asian type. This coincided well with the results of karyotypic evolution of these geographic variants. Among the nine F2 hybrids examined, one female consistently showed 37 chromosomes with one X chromosome. This XO female appeared to be a normal female and to have been a sporadic natural occurrence.
Complementation between senescent human diploid cells and a thymidine kinase-deficient murine cell line
Authors: Norwood T.H. , Zeigler C.J.
Published: May 2008

Active thymidine incorporation was observed in both parental nuclei in heterokaryons derived via polyethylene glycol-mediated fusion of postreplicative “senescent” human diploid fibroblast-like cells and a thymidine kinase-deficient murine cell line (3T3der-4E). Some increase of the 3H-thymidine labeling index was also apparent in unfused 3T3der-4E cells co-cultivated with senescent cells, consistent with metabolic cooperation. While no human metaphases could be detected in control hybrid preparations, hybrid metaphase figures containing essentially the entire human complement were demonstrated in the fused cultures as early as 24 h after fusion; the morphology of the human chromosome (bi-armed) suggested that the senescent human cells were stimulated to reinitiate replicative DNA synthesis rather than repair.
Autoradiographic study of RNA synthesis during meiotic prophase in the human oocyte
Authors: Hartung M. , Stahl A.
Published: May 2008

The incorporation of SH-uridine in oogonia and oocytes during meiotic prophase I was studied in three human fetuses 13, 18, and 19 weeks old. Following a 40- or 60-min pulse, intense nuclear and nucleolar labeling was observed in oogonia. During the preleptotene chromosome condensation stage, the heteropycnotic masses were unlabeled, while numerous silver grains were seen on the filaments persisting around these masses. During leptotene, chromosomal and nucleolar RNA synthesis was significant, but less than that in the oogonia. The rate of incorporation declined rapidly during zygotene and fell to a very low level at early pachytene. Throughout pachytene no nucleolar RNA synthesis was observed. Chromosomal RNA synthesis progressively recovered during middle pachytene, was of moderate intensity at late pachytene, and increased again at early diplotene. Nucleolar RNA synthesis was very intense at early diplotene, at the same time as nucleolar size and basophilia increased.
Rearrangements involving four chromosomes in a child with congenital abnormalities
Authors: Seabright M. , Gregson N. , Pacifico E. , Mould S. , Ryde J. , Pearson J. , Bradley A.
Published: May 2008

This report describes a complex structural rearrangement between chromosomes X and 1 and a 7;13 translocation (together involving six break points) in a child with multiple congenital defects. Both parents showed a normal chromosome complement, suggesting that the changes may have originated either in a gametic nucleus or at a very early stage of zygotic development.
A long unidentifiable extra chromosomal segment – a possible duplication of human 7q
Authors: Wahrman J. , Cohen M.M. , Rosenmann A. , Goitein R. , Richler C. , Dagan J.
Published: May 2008

Limitation of current techniques in identifying extra chromosomal segments arising de novo is illustrated by a putative case of a duplication of the long arm of chromosome 7. The propositus, demonstrating multiple congenital anomalies and severe mental retardation, had a large extra segment of chromatin on chromosome 7q that was absent in his parents. The banding pattern of this segment resembled that of the long arm of chromosomes 7, 8, or 9. Various procedures indicated that the additional material did not include the secondary constriction of 9q. The phenotype of the propositus did not fit well with that of trisomy 8.
Multiple cytogenetic methods used to identify a new structural rearrangement of the human X chromosome
Authors: de la Chapelle A. , Grönman P. , Latt S.A.
Published: May 2008

A woman with primary amenorrhea and pure gonadal dysgenesís had two cytogenetically abnormal cell lines. The karyotype was 45, X in 56–95 % of mitoses from lymphocytes and skin fibroblasts. In the remaining 5–44 % of the cells there was, in addition to a normal X, a structurally abnormal X chromosome interpretable as pter→q21::qll→pter or pter→q21::ql3→pter. The abnormal X chromosome was heterocyclic and had a normal centromere plus an extra C band in the long arm. Detailed interpretation of the structural rearrangements of this chromosome required the use of both Q-, G-, and C-banding and the BrdU-Hoechst 33258 technique.
Testicular cells lysostripped of H-Y antigen organize ovarian follicle-like aggregates
Authors: Ohno S. , Nagai Y. , Ciccarese S.
Published: May 2008

A suspension of free testicular cells were obtained by mild trypsin treatment from newborn BALB/c testes, and their plasma membrane H-Y antigen sites were blocked (lysostripped) by an excess of H-Y antibody of proven specificity and potency (45 min in ice). Upon 16 h of the Moscona-type rotation culture, these treated testicular cells yielded primarily spherical aggregates, more than half of which demonstrated a strong resemblance to ovarian follicles. The resemblance was particularly striking between the smallest testicular folliculoids and primordial ovarian follicles that abound in the newborn female gonad. Under the same condition, control serum-treated testicular cells primarily yielded cylindrical tubular structures that can be very long. Over a critical range, concentrations of H-Y antibody apparently influenced the frequency of testicular folliculoid formation. The above directly supports the proposed testis-organizing function of H-Y antigen and is certainly compatible with the genetic situation encountered in the wood lemming (Myopus schisticolor), that in the functional absence of H-Y antigen, XY gonadal cells readily organize an ovary.
Ribosomal and human-homologous repeated DNA distribution in the orangutan (Pongo pygmaeus)
Authors: Gosden J. , Lawrie S. , Seuanez H.
Published: May 2008

The distributions of ribosomal (18s + 28s) DNA in the orangutan (Pongo pygmaeus) and lowland gorilla (Gorilla gorilla gorilla) have been investigated by hybridization in situ, and the results compared with the distribution of this DNA in man, the chimpanzee (Pan troglodytes), and the mountain gorilla (Gorilla g. beringei) and with the distribution of sequences homologous to human satellite DNAs in these species. In the orangutan all sites of ribosomal DNA also contain human-homologous repeated DNA (HHR-DNA), and only the Y chromosome contains HHR-DNA but no ribosomal DNA (rDNA). In man and the chimpanzee, all sites of rDNA also contain HHR-DNA, but there are autosomal sites containing HHR-DNA that do not contain rDNA. In the lowland gorilla, only two pairs of chromosomes contain rDNA, and one of these contains HHR-DNA. The distribution of rDNA in all these species can be derived from that in the orangutan by postulating the loss of rDNA following Robertsonian translocation, pericentric inversion, or terminal deletion. Evidence is cited indicating that, at least in man, sites containing satellite DNA, which do not contain rDNA, are routinely found in association with the nucleolus, and it is suggested that this association may indicate a functional relationship between rDNA and HHR-DNA in man and the hominoid apes.
Chromosomal polymorphism in Equus hemionus
Authors: Ryder O.A.
Published: May 2008

The first cytogenetic studies of the Turkmenian kulan, Equus hemionus kulan, are reported, and a polymorphism in diploid chromosome number is described. Chromosome fusion is apparently involved in the alterations of the karyotype of E. hemionus kulan (2n = 55, 54) when compared to the karyotype of the onager, E, hemionus onager (2n = 56). Additionally, the rearrangement involved has been identified in animals unrelated through captive breeding; inheritance of the fusion chromosomes has also been observed.
Chromosome structure and function in man
Authors: Hungerford D.A. , Hungerford A.M.
Published: May 2008

Pachytene maps of chromosomes 16, 17, and 18 have been constructed and are illustrated diagrammatically and in comparison with photomicrographs of representative bivalents. Their relative lengths and arm ratios are similar to the corresponding values at metaphase. Bivalent 17 is characterized by overall pale staining relative to that of the remainder of the autosomal complement; it also exhibits a region of heavily compacted chromatin situated medially in its long arm, unlike 16 and 18, each of which has a compacted region adjacent to the centromere. Structural polymorphism was not observed during this study. Comparison between these maps and the corresponding diagrams (Paris Conference, 1971, Supplement, 1975) of metaphase G-banding provides a quantitative estimate of the increment of structural detail present at pachytene. There is a general compatibility between the two types of pattern, strongly suggesting that bands represent aggregates of adjacent chromomeres. For these reasons, and because chromomere patterns are of natural occurrence, pachytene is suggested as a reference standard for chromosome structural differentiation visualized at metaphase. A number of different methods are known to effect additional metaphase banding detail. Most of these are not widely used, even though there is need for finer detail in the visual or cytophotometric analysis of increasingly more subtle rearrangements of the genome. Some examples are given.
Variation in lateral asymmetry of human chromosome 1
Authors: Lin M.S. , Alfi O.S.
Published: May 2008

Variations in lateral asymmetry of human chromosome 1 were studied in 17 amniotic cell samples and eight blood samples by the 5-bromodeoxyuridine (BrdU) quenching of 4’-6-diamidino-2-phenylindole (DAPI) fluorescence. The size and the relative proportion of the bright fluorescent spots on each chromatid in the heterochromatic region of chromosome 1 (1qh) are variable from different amniotic (or blood) samples after one cycle of BrdU incorporation. However, the particular pattern for a given chromosome 1 is consistent within the individual sample. Size variations were classified into three groups, and variations in the pattern (proportion) of bright fluorescence on each chromatid in the lqh region were classified into four groups. A preliminary estimate of the type and frequency of lateral asymmetry variations was obtained. These results suggest a high frequency of variability of heterochromatin in the population. The BrdU-DAPI fluorescence technique was found to be very useful for characterizing variations in the lqh region; variations in organization of heterochromatin DNA within the lqh region can be detected, and a simple system of nomenclature is proposed for naming the variations in this region.
Analysis of crossingover in man
Authors: Morton N.E.
Published: May 2008

Methods for constructing maps of male and female recombination are reviewed, including reporting of raw data, construction of standard lod tables, and analysis of heterogeneity. Chiasma distributions, physical assignments, nondisj unction, and chromosomal rearrangements are considered.
Karyological confirmation of conspicuous ZW sex chromosomes in two species of Pacific anguilloid fishes (Anguilliformes: Teleostomi)
Authors: Park E.H. , Kang Y.S.
Published: May 2008

Leukocyte and kidney cell cultures were used to examine the sex chromosomes of Japanese freshwater eels (Anguilla japonica) and conger eels (Astroconger myriaster). The conspicuous presence of ZW sex chromosomes, due to a drastic reduction in size of the W, was confirmed in both species, where the Z was the largest metacentric and the W was the smallest metacentric in a diploid karyotype of 38 chromosomes in both species. These species are the first examples of the ZW type of heteromorphism in eels.
Chromosomal imbalance in ovulated oocytes from Syrian hamsters (Mesocricetus auratus) and Chinese hamsters (Cricetulus griseus)
Authors: Hansmann I. , Probeck H.D.
Published: May 2008

Chromosomes were studied in ovulated oocytes from Syrian hamsters (Mesocricetus auratus) and Chinese hamsters (Cricetulus griseus) to assess the degree of chromosomal imbalance after first meiotic division of oogenesis. Only one hyperploid oocyte among 307 studied was detected in the former, and none in oocytes from the latter species. Structural chromosome alterations, single chromatids due to presegregation, and diploid chromosome sets resulting from meiotic blockage were not observed. The hormones which were used to stimulate ovulation apparently did not enhance first meiotic cleavage errors in these hamster oocytes. The low figures of chromosomal anomalies in hamster oocytes are compared to those from a large sample of mouse oocytes obtained from three different strains and prepared under identical conditions. The relevance of these findings to the obviously higher impact of chromosomal aneuploidy in man is discussed.
The chromosomes of the southern elephant seal, Mirounga leonina(Phocidae: Mammalia)
Authors: Robinson T.J. , Condy P.R.
Published: May 2008

Chromosome analyses were carried out on bone marrow cells from three elephant seal pups (Mirounga leonina), a species characterized by a 2n = 34 chromosome number. Arm ratios for the different chromosomes were calculated to facilitate the classification of chromosomes into groups. The karyotype of the southern elephant seal differs from other reported 34-chromosome phocids in the morphology of the Y chromosome and in that of one of the autosomal chromosome pairs.
Meiotic studies of translocations causing male sterility in the mouse
Authors: Forejt J.
Published: May 2008

Unusual meiotic behavior of the XY chromosome pair was observed in sterile male mice doubly heterozygous for two Robertsonian translocations, Rb(16.17)7Bnr and Rb(8.17)1Iem. Nonrandom association between the X chromosome and the translocation configuration, ascertained from the frequencies of relevant C-band contacts, was found in 9 of 10 sterile males. Besides the nonrandom association, the XY chromosomes showed signs of impaired condensation, as judged by measurement of their lenghts at diakinesis/MI of the first meiotic division. In contrast, neither nonrandom contact nor decondensation of the XY chromosomes pair was found in fertile males heterozygous for a single Robertsonian translocation, Rb1Iem or Rb7Bnr. The present observations lend indirect support to the working hypothesis advanced previously, the assumption that interference with X-chromosome inactivation is a possible cause of spermatogenic breakdown in carriers of various male-sterile chromosomal translocations. Alternative explanations of the available data, which cannot be ruled out, are briefly discussed.
Regional assignments of the loci AK3, ACONs, and ASS on human chromosome 9
Authors: Carritt B. , Povey S.
Published: May 2008

Experiments are described in which human cells carrying balanced reciprocal translocations involving four different regions of chromosome 9 were fused with a Chinese hamster cell line and the resulting hybrids used to obtain subchromosomal assignments of the loci ASS, AK3, and ACONs. ASS was localized on the distal portion of the long arm of chromosome 9, in the region 9q34→9qter, and AK3and ACONson the short arm, in the region 9pter→9pl3.
Genetic studies in NZB mice
Authors: Raveché E.S. , Tjio J.H. , Steinberg A.D.
Published: May 2008

The presence of hyperdiploidy was studied in New Zealand black (NZB) mice and the progeny of NZB × DBA/2 crosses and backcrosses. Hyperdiploidy was observed in the spleens of a majority of NZB mice but not in DBA/2 mice at 1 year of age. In crosses of NZB with the DBA/2 strain, hyperdiploidy was observed only in backcrosses to NZB. Hyperdiploidy appeared to be determined by a recessively inherited trait and was not related to the presence of other immunological abnormalities, including splenomegaly, hypergammaglobulinemia, and spontaneous antibodies cytotoxic for T cells and reactive with single-stranded DNA. Abnormal cells were not present in Concanavalin A-stimulated 48-h spleen cultures. There was no difference in the in vitro sister chromatid exchange rate between the autoimmune NZB strain and the non-autoimmune DBA/2 strain. Identification of NZB chromosomes by banding analysis showed that chromosomes 15 and 17 were frequently present in more than two copies in hyperdiploid spleen cells. NZB chromosomes also had reduced C-banding in an autosomal pair. These studies indicate that chromosomal abnormalities which occur in NZB mice may be useful as genetic and cytogenetic markers.
Molecular and Clinical Characterization of a Novel
SCN5A
Mutation Associated With Atrioventricular Block and Dilated Cardiomyopathy
Authors: Ge Junbo , Sun Aijun , Paajanen Vesa , Wang Shijun , Su Chunxi , Yang Zhiyin , Li Ying , Wang Shaochun , Jia Jianguo , Wang Keqiang , Zou Yunzeng , Gao Lizhi , Wang Kun , Fan Zheng
Published: May 2008

Background—

Increased susceptibility to dilated cardiomyopathy has been observed in patients carrying mutations in the
SCN5A
gene, but the underlying mechanism remains unclear. In this study, we identified and characterized, both in vitro and clinically, an
SCN5A
mutation associated with familial progressive atrioventricular block of adult onset and dilated cardiomyopathy in a Chinese family.

Methods and Results—

Among 32 family members, 5 were initially diagnosed with atrioventricular block after age 30; 4 were studied, 3 of whom later developed dilated cardiomyopathy. We found a heterozygous single-nucleotide mutation resulting in an amino acid substitution (A1180V) in all studied patients and in 6 other younger unaffected members but not in 200 control chromosomes. When expressed with the β1 subunit, the mutated channels exhibited a −4.5-mV shift of inactivation with slower recovery leading to a rate-dependent Na
+
current reduction and a moderate increase in late Na
+
current. Clinical study revealed that although QRS duration decreased with increasing heart rate in noncarrier family members, this change was blunted in unaffected carriers whose ECG and heart function were normal. Resting corrected QT interval of unaffected carriers was significantly longer than that of noncarriers, even though it was still within the normal range.

Conclusions—

A1180V expresses a mild Na
+
channel phenotype in vitro and a corresponding clinical phenotype in unaffected mutation carriers, implying that A1180V caused structural heart disease in affected carriers by disturbing Na
+
influx and, hence, cellular Na
+
homeostasis. The high penetrance of A1180V suggests this phenotype as a high risk factor for dilated cardiomyopathy with preceding atrioventricular block.
Three-Dimensional Ultrasound for Image-Guided Mapping and Intervention
Authors: Okumura Yasuo , Henz Benhur D. , Johnson Susan B. , Bunch T. Jared , O’Brien Christine J. , Hodge David O. , Altman Andres , Govari Assaf , Packer Douglas L.
Published: May 2008

Background—

Multiple factors create discrepancies between electroanatomic maps and merged, preacquired computed tomographic images used in guiding atrial fibrillation ablation. Therefore, a Carto-based 3D ultrasound image system (Biosense Webster Inc) was validated in an animal model and tested in 15 atrial fibrillation patients.

Methods and Results—

Twelve dogs underwent evaluation using a newly developed Carto-based 3D ultrasound system. After fiducial clip markers were percutaneously implanted at critical locations in each cardiac chamber, 3D ultrasound geometries, derived from a family of 2D intracardiac echocardiographic images, were constructed. Point-source error of 3D ultrasound-derived geometries, assessed by actual real-time 2D intracardiac echocardiographic clip sites, was 2.1�1.1 mm for atrial and 2.4�1.2 mm for ventricular sites. These errors were significantly less than the variance on CartoMerge computed tomographic images (atria: 3.3�1.6 mm; ventricles: 4.8�2.0 mm;
P<
0.001 for both). Target ablation at each clip, guided only by 3D ultrasound-derived geometry, resulted in lesions within 1.1�1.1 mm of the actual clips. Pulmonary vein ablation guided by 3D ultrasound-derived geometry resulted in circumferential ablative lesions. Mapping in 15 patients produced modestly smaller 3D ultrasound versus electroanatomic map left atrial volumes (98�24 cm
3
versus 109�25 cm
3
,
P<
0.05). Three-dimensional ultrasound-guided pulmonary vein isolation and linear ablation in these patients were successfully performed with confirmation of pulmonary vein entrance/exit block.

Conclusions—

These data demonstrate that 3D ultrasound images seamlessly yield anatomically accurate chamber geometries. Image volumes from the ultrasound system are more accurate than possible with CartoMerge computed tomographic imaging. This clinical study also demonstrates the initial feasibility of this guidance system for ablation in patients with atrial fibrillation.
Association of Serum Creatinine With Abnormal Hemodynamics and Mortality in Pulmonary Arterial Hypertension
Authors: Shah Sanjiv J. , Thenappan Thenappan , Rich Stuart , Tian Lu , Archer Stephen L. , Gomberg-Maitland Mardi
Published: May 2008

Background—

Renal dysfunction predicts mortality in patients with cardiovascular disease. How renal dysfunction relates to hemodynamics and mortality in pulmonary arterial hypertension (PAH) remains unclear.

Methods and Results—

We performed a cohort study of 500 patients with World Health Organization group I PAH from 1982 to 2006 with data on demographics, comorbidities, medications, functional class, laboratory tests, exercise testing results, and hemodynamics. Serum creatinine (SCr) was determined on entry into the study (initial PAH clinic visit). Vital status was determined from hospital records and the Social Security Death Index. We used a Cox proportional hazards analysis to determine whether SCr was an independent predictor of mortality. Mean age on entry into the study was 48±14 years, and 79% of subjects were female. Mean SCr was 1.05±0.35 mg/dL. Elevated SCr was associated with higher right atrial pressure and lower cardiac index. During a median follow-up of 3.5 years, 279 deaths (55.8% of the cohort) occurred. Compared with patients with SCr <1.0 mg/dL, those with SCr 1.0 to 1.4 mg/dL and SCr >1.4 mg/dL had an increased hazard ratio of death (unadjusted hazard ratio 1.65, 95% confidence interval 1.26 to 2.17,
P
<0.0001 for SCr 1.0 to 1.4 mg/dL; unadjusted hazard ratio 2.54, 95% confidence interval 1.73 to 3.71,
P
<0.0001 for SCr >1.4 mg/dL). On multivariable analysis, we found a significant interaction between SCr and right atrial pressures (interaction
P
<0.0001); increased SCr best predicted death in patients with right atrial pressure <10 mm Hg.

Conclusions—

Renal dysfunction is associated with a worse hemodynamic profile and is an independent predictor of mortality in PAH. Measurement of SCr is practical and offers a simple way to noninvasively predict outcome.
Comparing the Vertical Structures of Weighting Functions and Adjoint Sensitivity of Radiance and Verifying Mesoscale Forecasts Using AIRS Radiance Observations
Authors: Carrier Matthew J. , Zou Xiaolei , Lapenta William M.
Published: May 2008

An adjoint sensitivity analysis is conducted using the adjoint of the hyperspectral radiative transfer model (RTM) that simulates the radiance spectrum from the Advanced Infrared Sounder (AIRS). It is shown, both theoretically and numerically, that the height of the maximum sensitivity of radiance in a channel could be higher or lower than the height of the maximum weighting function of that channel. It is shown that the discrepancy between the two heights is determined by the vertical structures of the atmospheric thermodynamic state. The sensitivity finds the level at which changes in temperature and/or moisture will have the largest influence on the simulated brightness temperature (BT), and the maximum weighting function (WF) height indicates the level where the model atmosphere contributes most significantly to the emission at the top of the atmosphere. Based on the above findings, an adjoint method for forecast verification using AIRS radiances is presented. In this method, model forecasts are first mapped into radiance space by an RTM so that they can be compared directly with the observed radiance values. The adjoint sensitivity analysis results are then used to connect the deviations of the model forecasts from observed radiances to the changes of temperature and moisture variables in model space. This adjoint sensitivity based model verification provides useful information on forecast model performances based on indirect observations from satellites.
Using Model Reduction Methods within Incremental Four-Dimensional Variational Data Assimilation
Authors: Lawless A. S. , Nichols N. K. , Boess C. , Bunse-Gerstner A.
Published: May 2008

Incremental four-dimensional variational data assimilation is the method of choice in many operational atmosphere and ocean data assimilation systems. It allows the four-dimensional variational data assimilation (4DVAR) to be implemented in a computationally efficient way by replacing the minimization of the full nonlinear 4DVAR cost function with the minimization of a series of simplified cost functions. In practice, these simplified functions are usually derived from a spatial or spectral truncation of the full system being approximated. In this paper, a new method is proposed for deriving the simplified problems in incremental 4DVAR, based on model reduction techniques developed in the field of control theory. It is shown how these techniques can be combined with incremental 4DVAR to give an assimilation method that retains more of the dynamical information of the full system. Numerical experiments using a shallow-water model illustrate the superior performance of model reduction to standard truncation techniques.
Bred Vectors and Tropical Pacific Forecast Errors in the NASA Coupled General Circulation Model
Authors: Yang Shu-Chih , Kalnay Eugenia , Cai Ming , Rienecker Michele M.
Published: May 2008

The breeding method has been implemented in the NASA Global Modeling and Assimilation Office coupled general circulation model (CGCM) in its operational configuration in which ocean data assimilation is used to initialize the coupled forecasts. Bred vectors (BVs), designed to capture the dominant growing errors in the atmosphere–ocean coupled system, are applied as initial ensemble perturbations. The potential improvement for ensemble prediction is investigated by comparing BVs with the oceanic growing errors, estimated by the one-month forecast error from the nonperturbed forecast. Results show that one-month forecast errors and BVs from the NASA CGCM share very similar features: BVs are clearly related to forecast errors in both SST and equatorial subsurface temperature—in particular, when the BV growth rate is large. Both the forecast errors and the BVs in the subsurface are dominated by large-scale structures near the thermocline. Results suggest that the forecast errors are dominated by dynamically evolving structures related to the variations of the background anomalous state, and that their shapes can be captured by BVs, especially during the strong 1997/98 El Niño. Hindcast experiments starting from January 1997 with one pair of BVs achieve a significant improvement relative to the control (unperturbed) hindcast by capturing many important features of this event, including the westerly wind burst in early 1997.