bluuebunny/crossref_metadata_2025 huggingface dataset:
Construction of Interval Wavelet Based on Restricted Variational Principle and Its Application for Solving Differential Equations
Authors: Mei Shu-Li , Lv Hong-Liang , Ma Qin
Published: May 2008

Based on restricted variational principle, a novel method for interval wavelet construction is proposed. For the excellent local property of quasi‐Shannon wavelet, its interval wavelet is constructed, and then applied to solve ordinary differential equations. Parameter choices for the interval wavelet method are discussed and its numerical performance is demonstrated.
Inhibitory Effect on Cerebral Inflammatory Response following Traumatic Brain Injury in Rats: A Potential Neuroprotective Mechanism of N‐Acetylcysteine
Authors: Chen Gang , Shi Jixin , Hu Zhigang , Hang Chunhua
Published: May 2008

Although N‐acetylcysteine (NAC) has been shown to be neuroprotective for traumatic brain injury (TBI), the mechanisms for this beneficial effect are still poorly understood. Cerebral inflammation plays an important role in the pathogenesis of secondary brain injury after TBI. However, it has not been investigated whether NAC modulates TBI‐induced cerebral inflammatory response. In this work, we investigated the effect of NAC administration on cortical expressions of nuclear factor kappa B (NF‐κB) and inflammatory proteins such as interleukin‐1β (IL‐1β), tumor necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), and intercellular adhesion molecule‐1 (ICAM‐1) after TBI. As a result, we found that NF‐κB, proinflammatory cytokines, and ICAM‐1 were increased in all injured animals. In animals given NAC post‐TBI, NF‐κB, IL‐1β, TNF‐α, and ICAM‐1 were decreased in comparison to vehicle‐treated animals. Measures of IL‐6 showed no change after NAC treatment. NAC administration reduced brain edema, BBB permeability, and apoptotic index in the injured brain. The results suggest that post‐TBI NAC administration may attenuate inflammatory response in the injured rat brain, and this may be one mechanism by which NAC ameliorates secondary brain damage following TBI.
Dependence on Frequency of the Electromagnetic Field Distribution inside a Cylindrical Cavity Excited through an Off-Axis Aperture
Authors: Consoli Fabrizio , Celona Luigi , Ciavola Giovanni , Gammino Santo , Maimone Fabio , Catalano Rocco Salvatore , Barbarino Sebastiano , Mascali David , Tumino Livia
Published: May 2008

To explain the relevant changes in the electron cyclotron resonance ion source behaviour for small variations of the exciting radiation frequency, we determine the spatial distribution of the field within the cavity for every resonant mode.
Hoxb7 Inhibits Transgenic HER-2/neu–Induced Mouse Mammary Tumor Onset but Promotes Progression and Lung Metastasis
Authors: Chen Hexin , Lee Ji Shin , Liang Xiaohui , Zhang Huiping , Zhu Tao , Zhang Zhe , Taylor M. Evangeline , Zahnow Cynthia , Feigenbaum Lionel , Rein Alan , Sukumar Saraswati
Published: May 2008

Our previous studies have shown that HOXB7 mRNA is overexpressed in ∼50% of invasive breast carcinomas and promotes tumor progression in breast cancer cells grown as xenografts in mice. In silico analysis of published microarray data showed that high levels of HOXB7 predict a poor outcome in HER-2–positive (P = 0.046), but not in HER-2–negative breast cancers (P = 0.94). To study the function of HOXB7 in vivo in the context of HER-2 overexpression, we generated mouse mammary tumor virus (MMTV)-Hoxb7 transgenic mice, and then crossed them with MMTV-HER-2/neu transgenic mice. In the mice carrying both Hoxb7 and HER-2/neu transgenes, Hoxb7 plays a dual role in mammary tumorigenesis. In double transgenic mice, overexpression of Hoxb7 delayed tumor onset and lowered tumor multiplicity. However, consistent with the clinical data, once the tumors appeared, their growth was faster and metastasis to the lungs occurred at a higher frequency. Our data show, for the first time, that deregulated expression of Hoxb7 in mammary tumor cells can significantly modulate HER-2/neu-oncogene induced tumorigenesis in vivo. [Cancer Res 2008;68(10):3637–44]
Retinopathy in Patients with Diabetic Ophthalmoplegia
Authors: Acaroglu Golge , Akinci Arsen , Zilelioglu Orhan
Published: May 2008

Purpose: To compare patients with palsy of the 3rd, 4th or 6th cranial nerve due to diabetes mellitus (DM) with controls matched for age, sex and disease duration in terms of the presence and severity of diabetic retinopathy. Patients and Method: Thirty-three diabetic patients with cranial nerve palsies and 33 age- and sex-matched controls with the same duration of disease were included in this case-control study. Groups were evaluated in terms of the type of DM, presence and level of diabetic retinopathy and coexisting systemic diseases. Outcomes were compared by χ2 and paired-sample tests. Results: Eleven patients had diabetic retinopathy in the study group. In the control group, 23 patients had diabetic retinopathy. Differences in the presence and severity of diabetic retinopathy between the two groups were found to be statistically significant (p = 0.028 and p = 0.018, respectively). Conclusion: Presence and level of diabetic retinopathy are significantly lower in diabetics with cranial nerve palsy than in the age-, sex- and disease-duration-matched controls.
Noninvolvement of the human X chromosome in X-ray-induced exchanges
Authors: Seabright Marina
Published: May 2008

The patterns of breaks and exchanges induced by X irradiation of human lymphocytes obtained from individuals with abnormal sex-chromosome complements have been analyzed and compared with similarly induced aberrations in cells from normal individuals. Statistical analysis showed that the X chromosome(s) showed a different pattern of response to X irradiation than did the autosomes. Neither the active nor the inactive X behaved like the autosomes in this respect.
Chromosome breakage and xenotropic C-type virus in embryonic cultures from New Zealand black mice
Authors: Emerit I. , Bernard C. , Housset E.
Published: May 2008

A considerable increase in chromatid and chromosome breaks, as well as excessive fragmentation and “pulverization” of whole metaphase plates was observed in embryonic fibroblast cultures from New Zealand black mice. A C-type RNA virus with a xenotropic host range was isolated from the supernatant fluid of co-cultures of NZB cells and heterologous permissive cells (SIRC cell line). One of the NZB cultures produced this virus without amplification by co-cultivation after spontaneous transformation of the cells. NZB cells are supposed to lack normal restriction of complete xenotropic virus expression and to release this endogenous virus spontaneously at a high level. It is hypothesized that the excessive chromosome damage observed in these cell cultures is related to the permanent production of virus, thus indicating a chromosome breaking effect of endogenous viruses.
Very large analogy of chromosome banding between Cebus capucinus(Platyrrhini) and man
Authors: Dutrillaux B.
Published: May 2008

The karyotype of a platyrrhine, Cebus capucinus, is compared with that of man and other catarrhines. It was found that a large degree of analogy of chromosome banding exists among the different species. A common origin for the platyrrhines and the catarrhines can thus be deduced. Furthermore, it becomes possible to reconstruct, to a great extent, the karyotype of the last common ancestor of all of the simians.
Regional assignment of human genes TPI1, GAPDH, LDHB, SHMT, and PEPB on chromosome 12
Authors: Law M.L. , Kao F.T.
Published: May 2008

Karyological analysis was performed on a series of human-Chinese hamster cell hybrids containing deletions of human chromosome 12. Chromosome breakage was produced by treatment of the cells with either X-rays or 5-bromodeoxyuridine and near-visible light. The hybrid clones were analyzed for the presence or absence of the following five human gene markers known to be located on chromosome 12: triosephosphate isomerase-1 (TPI1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), lactate dehydrogenase-B (LDHb), serine hydroxymethyltransferase (SHMT), and peptidase-B (PEPB). Based on the correlation between the isozyme markers and karyological analysis of these clones, a regional map of the five human genes on chromosome 12 was established. The linear order for these genes is: pteτ-TPI1-GAPDH-LDHB-centromere-SHMT-PEPB-qteτ. The locations of these genes are: TPI1, GAPDH, LDHB: pter→p12; SHMT: q12→q14; PEPB: ql4→qter. Statistical analysis similar to that of Goss and Harris (1975, 1911a, b) has been performed on the segregation data in the hybrid clones. The statistical map, in general, agrees with the cytogenetic map and further localizes PEPB to 12q21.
Incidence of nondisjunction in mouse oocytes
Authors: Hansmann I. , El-Nahass E.
Published: May 2008

The chromosomes of more than 3000 ovulated mouse oocytes from strains C3H/Han, NMRI/Han, and (101 x C3H)F1 have been analyzed after spontaneous and hormonally induced ovulation. No significant difference in the incidence of nondisjunction was observed among the three strains with or without hormonal pretreatment. The incidence of nondisjunction was estimated to be 0.47% in NMRI/Han, 0.62% in C3H/Han, and 0.81%) in (101 x C3H)F1. The incidence of chromosomal imbalance after the first meiotic division was slightly higher after adding the events following presegregation. Diploidy-spontaneous and hormonally induced-reached a significant level in NMRI/Han. This may be interpreted as a consequence of hormonal interference with a genetically defined malfunction of gene product(s) during the late phase of oogenesis.
Comparative cytogenetic studies on the red muntjac, Chinese muntjac, and their F1 hybrids
Authors: Shi Liming , Ye Yingying , Duan Xingsheng
Published: May 2008

The chromosomes of the red (Indian) muntjac (2n = 6♀,7♂), the Chinese (Reeves) muntjac (2n = 46), and their F1 hybrids were studied with various banding techniques. G-banding showed that the two complements still have a high degree of homology despite the vast difference in diploid numbers between the two species. Cd-banding suggested that the X chromosome and chromosome 1 of the red muntjac are dicentric. Evidence indicates that both centric and repeated tandem translocations among the chromosomes of the Chinese muntjac evolved to form those of the red muntjac.
Yeast stimulation of bone marrow mitosis for cytogenetic investigations
Authors: Lee M.R. , Elder F.F.B.
Published: May 2008

We report a simple, dependable method for stimulating bone marrow mitosis in small mammals. Subcutaneous injections of a suspension of active baker’s yeast may elevate the mitotic index as much as six times or more. Additionally, the metaphases obtained are easily spread when air dried, and the chromosomes are readily banded. This method should prove useful to investigators who wish to use bone marrow as a source of chromosomes for cytotaxonomic studies or for studies of specific chromosome damage in vivo.
The unusual karyotype of the lesser kudu, Tragelaphus imberbis
Authors: Benirschke K. , Rüedi D. , Müller H. , Kumamoto A.T. , Wagner K.L. , Downes H.S.
Published: May 2008

The chromosome set of the lesser kudu, Tragelaphus imberbis, consists of 38 elements in both sexes. In contrast to most other members of the bovid subfamily Tragelaphinae, both the X and the Y chromosomes are compound, having fused with identical autosomes from ancestors presumed to have higher chromosome numbers. From a comparison of the unusual sex chromosomal rearrangements that have occurred in this family, a hypothetical lineage has been derived. This family tree and the details of various banding studies in the lesser kudu are described.
Tandem fusion, centric fusion, and chromosomal evolution in the cotton rats, genus Sigmodon
Authors: Elder F.F.B.
Published: May 2008

G-banded and C-banded karyotypes of three closely related and morphologically similar species of cotton rats, Sigmodon hispidus (2n = 52; 52 autosomal arms), S. mascotensis (2n = 28; 28 autosomal arms), and S. arizonae (2n = 22,24; 38 autosomal arms) are presented and compared. Despite the enormous difference between the higher diploid number of hispidus and the lower diploid numbers of mascotensis and arizonae, a great deal of G-band homology is retained. If the karyotype of hispidus is considered ancestral in the group, then chromosome evolution toward lower diploid numbers has proceeded through the fixation of a large number of both tandem and centric fusions. Centromeric heterochro-matin has not, however, persisted as interstitial C-band material on the tandem fusion products. The karyotypes of mascotensis and arizonae share several tandem fusion products of hispidus chromosomes indicating a common origin of the former two species from an ancestor of intermediate diploid number. Chromosome evolution from the ancestral hispidus-like karyotype to the karyotype of the common ancestor of arizonae and mascotensis proceeded almost exclusively by tandem fusion. This orthokaryotypic trend continued in the evolution of the karyotype of modern mascotensis. In the line leading from the arizonae-mascotensis ancestor to modern arizonae a trend of centric fusion predominated.
High rate of sister chromatid exchanges of Bloom’s syndrome chromosomes is corrected in rodent human somatic cell hybrids
Authors: Alhadeff B. , Velivasakis M. , Pagan-Charry I. , Wright W.C. , Siniscalco M.
Published: May 2008

The high rate of sister chromatid exchange (SCE) characteristic of cultured somatic cells from patients with Bloom’s syndrome (BS) was found to be fully corrected in BS chromosomes retained by somatic cell hybrids between Chinese hamster cells (CHO-YH 21) and BS fibroblasts (GM 1492), independent of the type and the number of human chromosomes retained. On the contrary, the average rate of SCE per Chinese hamster chromosome remained unaffected by hybridization with both BS and normal human cells. A partial suppression of SCE of about 30% was observed in the BS cells themselves when these were co-cultivated with Chinese hamster/Bloom’s syndrome hybrid cells. In these hybrids, the rate of SCE per chromosome (Chinese hamster or human) was unaffected by co-cultivation.
Visible light observations on the kinetochore of the Indian muntjac, Muntiacus muntjac, Z.
Authors: Brown P.A. , Loughman W.D.
Published: May 2008

We report here a silver stain technique (Kt stain) for locating the kinetochore (centromere body) without concomitant staining of C-band material. We compare our observations with those obtained from C-banding, Cd (centromeric dot) banding, and electron micrographs, and we report preliminary observations on Indian muntjac centromeres.
Studies of mammalian chromosome replication
Authors: Lau Y.-F. , Arrighi F.E.
Published: May 2008

The patterns of differential staining based on the effects of BrdU-substitution in chromosomal DNA have been examined in both metaphase chromosomes and prematurely condensed chromosomes (PCC) of interphase Chinese hamster cells. Results indicate that differential staining may be obtained in chromosomes from all stages of the cell cycle and correspond to the semi-conservative mode of DNA replication. Such fidelity of differential staining in both interphase and metaphase chromosomes suggests that components essential for induction of differential staining are present throughout the cell cycle and chromosomes may contain similar structures and organization throughout the cycle. Differential staining of metaphase chromosomes based on the effects of substitution of BrdU for thymidine in DNA has been extensively employed for various mutagen-carcinogen assays (Bloom and Hsu, 1975; Perry and Evans, 1975; Allen and Latt, 1976; Wolff, 1977, and Carrano et al., 1978) and studies on DNA replication and
Characteristics of HeLa strains: Permanent vs. variable features
Authors: Nelson-Rees W.A. , Hunter L. , Darlington G.J. , O’Brien S.J.
Published: May 2008

Characteristic rearranged human chromosome markers have been observed in a variety of HeLa cell sublines and in five suspected HeLa contaminant lines originally thought to be derived from differentiated tissues of different individual patients. The allozyme genetic signatures, representing the composite enzyme phenotype at eight polymorphic loci, of each of the studied contaminant lines were identical to each other and to those of HeLa cells. The probability that each of these lines would have an identical genetic signature (since the frequency of the HeLa genotype is 0.0017) is 4.2×10–15. Differences between cell lines, however, could be detected by isoelectric focussing of the isoenzymes for glucose-6-phosphate dehydrogenase. The cell lines, including CLL 74, the older Chang liver line, failed to express five liver-specific proteins. One protein was detected in a new liver cell culture. Variations in cytogenetic, biochemical, and differentiated functions during continuous cell culture are discussed.
Characterization of normal and rearranged human chromosomes by simultaneous Q- and R-banding with chromomycin A3
Authors: Mostacci C. , Ferraro M. , Pelliccia F. , Archidiacono N. , Rocchi M. , de Capoa A.
Published: May 2008

Simultaneous Q- and R-type banding patterns in human chromosomes have been achieved by staining with chromomycin A3. Some peculiarities of these patterns as compared to the patterns induced by other fluorochromes are described. The resolution power of this technique in analyzing structural rearrangements of human chromosomes is discussed.
Comparative chromosome studies in the family Leporidae (Lagomorpha, Mammalia)
Authors: Robinson T.J.
Published: May 2008

Chromosome banding patterns of Lepus saxatilis, 2n = 48, and Pronolagus rupestris, 2n = 42, are presented. Comparison of G-banded karyotypes allows the identification of similar elements in both species. The karyotype of P. rupestris differs from that of L. saxatilis by the presence of three fusions in the former. Comparative studies with the fusion products of Oryctolagus cuniculus indicate that fusion and not fission is the major factor in chromosomal evolution of these leporids. The chromosomal conservatism of the hares is compared to the karyotypic variability of the rabbits and possible causes are discussed.
A cytogenetic investigation of inherited true hermaphroditism in BALB/cWt mice
Authors: Eicher E.M. , Beamer W.G. , Washburn L.L. , Whitten W.K.
Published: May 2008

A predictably high incidence of true hermaphroditism (3%) among fetal BALB/cWt mice provided the opportunity for studying the cause of inherited hermaphroditism. G-banded liver metaphase chromosomes were analyzed from 20 fetal hermaphrodites and from 15 normal female and male littermate controls. All hermaphrodites and seven males were chromosomal mosaics, i.e. XO/XY or XO/XY/XYY. In each mosaic fetus there were more XO than XYY cells. From these findings we hypothesize that BALB/cWt hermaphrodites arise from non-disjunction and probable loss of the Y-chromosome during mitosis. Results from breeding experiments indicated that a defect in the BALB/cWt Y-chromosome per se accounts for its nondisjunction and loss.
Giant diploid oocytes as a cause of digynic triploidy in mammals
Authors: Funaki K. , Mikamo K.
Published: May 2008

Giant oocytes and zygotes twice the normal size from the Chinese hamster were studied embryologically and cytogenetically in order to clarify their significance as a cause of digynic triploidy. There were 6 (0.62%) giant eggs among 973 primary oocytes, 5 (1.37%) among 365 secondary oocytes from mature follicles missing ovulation, 3 (0.44%) among 677 secondary oocytes from oviducts, 4 (0.45%) among 886 one-cell zygotes, and 3 (0.49%) among 608 two-cell zygotes. The results indicated that follicles containing a giant oocyte might have a tendency to miss ovulation. But once ovulated, the giant eggs were fertilized normally and developed normally. uclear and chromosomal aspects were studied in 6 primary and 18 secondary oocytes, and 6 one-cell and 5 two-cell zygotes. There were mononuclear and binuclear giant oocytes, but the latter state was rarely maintained to metaphase II. The primary oocytes showed a diploid number of bivalents (22 tetrads) with normal chiasma configuration, and the secondary oocytes had 22 dyads with normal features, indicating normal segregation. The one-cell zygotes exhibited one set of diploid female pronuclear chromosomes and one set of haploid male pronuclear chromosomes in the late prophase. The two-cell zygotes were all digynic triploids; the tail of a fertilizing spermatozoon was attached. There were five XXX and six XXY giant triploids, giving a ratio of 1:1, as expected. t was suggested that the nuclear-cytoplasmic ratio of giant triploid eggs may be more favorable at least for preimplantation development than that of any other type of triploidy. Giant diploid oocytes may be an important source of human digynic triploids, in spite of the prevailing view from studies of marker chromosomes that suppression of first polar body extrusion is the predominant cause.
Homogeneously staining chromosome regions and double minutes in a mouse adrenocortical tumor cell line
Authors: George D.L. , Francke U.
Published: May 2008

We have used a number of banding techniques to analyze the chromosomal content of two sublines of the steroid-secreting mouse adrenocortical tumor cell line Y1. One of the sublines contains marker chromosomes with large “homogeneously staining regions” (HSRs). The other subline contains numerous double minutes, but no HSR. The presence of marker chromosomes shared by both sublines indicates their derivation from a common precursor. Both sublines are karyotypically stable, have similar growth rates, and exhibit positive staining for Δ5,3β-Hydroxysteroid dehydrogenase.
A spontaneous clone of Fanconi anemia fibroblasts with chromosome abnormalities and increased growth potential
Authors: Auerbach A.D. , Wolman S.R. , Chaganti R.S.K.
Published: May 2008

In a diploid fibroblast culture from a patient with Fanconi anemia (FA), we observed the evolution of a chromosomally abnormal clone that had an unusual proliferative advantage and increased growth potential compared with the diploid FA cells. Q-, G-, C-, and Ag-NOR banding analyses revealed that the clonal cells had the chromosomal complement 46, XY, –5,-21, + marl,+mar2, and were trisomic for a segment of the long arm of chromosome 5 and most of the long arm of No. 21. The retention of chromosome instability in the clonal cells indicates that the alteration in growth characteristics did not result from a mutation to the wild-type allele at the FA locus.
Human chromosome 11 is syntenic with human specific fibronectin production in human × mouse cell hybrids
Authors: Klinger H.P. , Ruoslahti E.
Published: May 2008

Evidence is presented indicating that human chromosome 11 carries a structural locus for fibronectin (FN). A panel of cell hybrids of FN fiber-producing normal human diploid cells fused with mouse A9 cells were immunofluorescently stained with species-specific, affinity purified antibodies to human FN (AHFN); similar anti-mouse FN antibodies (AMFN); and the nonspecies-specific anti-FN antiserum (AFN) which was used in an earlier study of this same hybrid panel (Eun and Klinger, 1980). All hybrids that had the human 11 produced extracellular fibers that fluoresced brightly when reacted with the AHFN and AFN. All other human chromosomes could be eliminated as being related to FN production, suggesting that the 11 carries a structural FN locus. This agrees with our earlier study in which a nonspecies-specific antiserum was used and with the preliminary report of Smith et al. (1979), who used a different cell system. The apparent discrepancy between these results and those of Owerbach et al. (1978), who reported synteny of FN with the human No. 8, was partly resolved in that one of their FN positive hybrids was found to react with our AMFN but not with the AHFN, suggesting that some other as yet undefined mechanism may be operating in their hybrids which were made with mouse LM/TK cells. The parental mouse A9 cells of our hybrids do not produce FN fibers, although a radioimmunoassay detects a small amount of mouse FN secreted into the medium. The fibers of some of our AHFN positive hybrids also react weakly with AMFN, but none react only with AMFN. This suggests that fibers produced by these hybrids bind some mouse as well as human FN. Why this is not so in all the producers is not clear.
Computer-assisted karyotyping system of banded chromosomes
Authors: Bruschi C. , Tedeschi F. , Puglisi P.P. , Marmiroli N.
Published: May 2008

The banding automatic system (BAS) we describe in this paper is a computer-assisted karyotyping system suitable for the analysis of both normal and abnormal karyotypes in banded chromosome specimens. In the BAS system recognition of the various features and constituents of the chromosomes is performed by an operator, whereas chromosome identification and classification are entrusted to a computer. The connection between operator and computer is the CYGENl program, which is tailored to distinguish chromosome morphology on the basis of the operator input band patterns alone. The karyotyping operation is therefore significantly speeded up: the operator simply has to read through a certain number of banded metaphases, encoding band-pattern data to the computer. The machine signals when the operation has gone through the whole karyotype or, for instance, when chromosomes are missing or present in extra number above the significance level from the analyzed metaphases. Chromosome identification and classification are then carried out by the computer, which performs as a real-time recognizing key. Moreover, the data being accumulated in the computer will provide a file of cytogenetic records accessible to the operator, as well as to the computer, for further diagnostic operations. The efficacy of the BAS system is demonstrated for the diagnosis of various structural aberrations, including a complex translocation. The processing of 20 metaphases by the method described takes 40–45 min, and a cytogenetic technician can make effective use of the system after 25–30 h of intensive training.
A cloned repeated DNA sequence in human chromosome heteromorphisms
Authors: Gosden J.R. , Lawrie S.S. , Cooke H.J.
Published: May 2008

A sequence derived by ECoRI restriction of human satellite DNA III has been cloned in λgt WES. The cloned DNA was used as a template for in vitro synthesis of cRNA, which was hybridized in situ to preparations of human metaphase chromosomes with a range of heterochromatic polymorphisms. Most of the hybridization was found on chromosome 1, and the amount of hybridization was related to the size of the C-band on this chromosome. Hybridization to other chromosomes was not related to the C-band size, although hybridization of total satellite DNA is proportional to C-band size. Total satellite DNAs contain a mixture of sequences, some of which are predominantly located on only one pair of chromosomes. Hybridization in situ is able to discriminate between such chromosome-specific sequences and the bulk of satellite DNA. Further analysis of satellite DNAs may identify sequences specific for every chromosome pair.
Comparison of the patterns of chromosomal late replication
Authors: Sheldon S. , Nichols W.W.
Published: May 2008

The patterns of late replication of human fetal lung fibroblasts and renal epithelium in culture were compared using a terminal pulse of 3H-TdR or of BrdU followed by autoradiography or Hoechst and Giemsa staining, respectively. Fifty cells from each of two fetuses were scored with each technique. Statistically significant quantitative differences were found in the pattern of late replication of the two tissues, but these differences were not consistent between the two individuals. In cultures from both of the fetuses examined, the autoradiographic grain counts over a given segment of chromosomes 1, 4, and 5 in the two tissues were shown to differ by a factor of 2 or more, while with BrdU chromosomes 1, 2, 4, and 13 had a labeling frequency that differed by 20% or more over a given band. The results suggest that although there are tissue-specific differences in the patterns of late replication, these differences do not reflect changes in the state of differentiation.
Comparison of the patterns of chromosomal late replication
Authors: Sheldon S. , Nichols W.W.
Published: May 2008

The patterns of late replication were compared on direct chromosome preparations from cells of chick embryo lung and kidney, as well as in cultures established from these tissues using tritium autoradiography. Fifty cells from each tissue were examined from each of five animals in vivo and three in vitro. Two- to four-fold differences in the frequencies with which a chromosome arm labeled were seen when lung and kidney were compared; however, labeling differences were often equally significant in the opposite direction when cells from another chick embryo were analyzed. The results obtained in vivo were comparable to those seen in vitro, indicating that cell-culture did not alter cell differentiation in a way that could be detected by late replication patterns. Variation in tissue-specific differences in late replication between individuals suggests that these patterns do not reflect differences in the differentiated state.
Chromosomal DNA homologous to Herpes simplex virus 1 in a mouse L-cell line
Authors: Henderson A.S. , Yu M.T. , Silverstein S.
Published: May 2008

Cytological hybridization in situ was used to identify chromosomes carrying DNA sequences homologous to Herpes simplex I (HSV-I) DNA in a HSV-transformed L-cell line. The L-cell karyotype, frequency of chromosome distribution, and possible homology to the normal chromosome complement are given. The major chromosomal sites for transcription of ribosomal RNA (rRNA) were also determined.
Immunochemical identification of the chick HPRT gene transferred from chick erythrocytes to mammalian somatic cells
Authors: Eun C.K. , Paik S.G. , Goldwasser P. , Shin S. , Klinger H.P.
Published: May 2008

Immunochemical methods were used to identify the genetic origin of hypoxanthine phosphoribosyltransferase (HPRT) expressed in heteroploid, HPRT-deficient mouse (A9) cells and Chinese hamster ovary (K627) cells, after these cells were fused with chick embryo erythrocytes and selected for resistance to hypoxanthine-aminopterin-thymidine (HAT) medium. All of the HAT-selected clones produced HPRT activity which was immunoprecipitable by an antiserum specific for chick HPRT, but not by an antiserum specific for mouse and hamster HPRT. Furthermore, the HPRT activity in these clones was electrophoretically indistinguishable from chick liver HPRT and clearly different from mouse liver HPRT. These data provide evidence that the HPRT activity expressed in cell hybrids produced by the fusion of HPRT-negative mammalian cells and chick erythrocytes containing genetically inactive nuclei is indeed coded by the chick HPRT gene and that an avian gene can be stably incorporated and correctly expressed in a mammalian cell.
Late replication studies in a human X/13 translocation: correlation with autosomal gene expression
Authors: Mohandas T. , Crandall B.F. , Sparkes R.S. , Passage M.B. , Sparkes M.C.
Published: May 2008

Chromosome replication pattern was reevaluated in an unbalanced X/13 translocation carrier, 46, X, der (X), t(X;13)(q27;q12), using the BudR-acridine orange technique. The translocated chromosome, Xpter→q27::13q12→13qter, was late replicating in all analyzed cells. The autosomal segment showed a replication pattern comparable to the two normal, and presumably genetically active, chromosome 13’s, with the exception of band 13q22, which was consistently late replicating. Measurements of red-cell levels of esterase D (ESD) (a marker assigned to 13ql4) showed a 50% increase in ESD activity, compared to that in normal controls and parents of the patient. This suggests noninactivation of the ESD locus on the der(X) chromosome, a finding consistent with the late-replication data.
Double minute chromosomes in a case of acute myelogenous leukemia resistant to chemotherapy
Authors: Cooperman B.S. , Klinger H.P.
Published: May 2008

Double minute (dmin) chromosomes were found in 17% of bone marrow cells in a 66-year-old woman with acute myelogenous leukemia (AML) which was resistant to treatment with cytosine arabinoside and daunorubicin hydrochloride. She died within 3 weeks of developing symptoms. The cells had a range of 36 to 49 chromosomes with a mode of 47 and a variety of structural and numerical chromosome abnormalities, as well as the presence of 1 to 10 C-chromatin negative dmins. In leukemias few cases with dmins have been reported. However, we suspect other cases may have been overlooked because of the very small size of some dmins. We hope that this report will direct attention to the presence of dmins in leukemic cells and, in particular, stimulate attempts to determine if there is a correlation between their presence and the resistance of the cells to chemotherapy or the rate of disease progression.
Specific resistance to 8-azaguanine in cells with normal hypoxanthine phosphoribosyltransferase (HPRT) activity: the role of guanine deaminase
Authors: Meyers M.B. , Shin S.
Published: May 2008

The role of guanine deaminase in selective cellular resistance to 8-azaguanine was examined, using eight mammalian cell lines and their subclonal derivatives isolated on the basis of increasing resistance to this drug. 8-Azaguanine and 6-thioguanine are synthetic analogs of guanine and are lethal to cells with normal hypoxanthine phosphoribosyltransferase (HPRT) activity. In principle, however, HPRT-positive cells could become selectively resistant to 8-azaguanine if, by any mechanism, the cells expressed higher levels of guanine deaminase. This is because 8-azaguanine, but not 6-thioguanine, is converted by this enzyme to a noncytotoxic metabolite, 8-azaxanthine. Our study shows that HPRT-positive cells inherently resistant to relatively high levels of 8-azaguanine contain high levels of guanine deaminase. In general, guanine deaminase activity was higher in 8-azaguanine-resistant cells, regardless of their HPRT activity. Our results support the view that elevated guanine deaminase activity constitutes a potential mechanism of selective 8-azaguanine resistance in cells with normal HPRT activity. Guanine deaminase levels were significantly elevated in HPRT-positive cells briefly exposed to sublethal concentrations of 8-azaguanine, but this elevation was transient. Long-term exposure of cells to increasingly higher levels of the drug did not lead to high stable levels of guanine deaminase, indicating that 8-azaguanine is not an inducer of guanine deaminase in the cells examined.
Sex vesicle-associated nucleolar organizers in mouse spermatocytes: localization, structure, and function
Authors: Knibiehler B. , Mirre C. , Hartung M. , Jean P. , Stahl A. , de Lanversin A. , Soler M.
Published: May 2008

Selective silver staining demonstrated that autosomal bivalents containing transcriptively active nucleolar organizers associated with the sex vesicle during pachytene of mouse spermatocytes. Later in pachytene, the nucleolar organizers covered the portion of the sex vesicle furthest from the attachment to the nuclear envelope. Hybridization in situ revealed the presence of rDNA in the silver-positive material. The nucleolus, formed from an autosomal bivalent, exhibited a large fibrillar center surrounded by an electron-opaque fibrillar zone. The nucleolar association with the sex vesicle was studied at early, middle, and late pachytene by hybridization in situ, NOR silver staining, and electron microscopy. These observations enabled us to further define the relationships of the nucleolar components with the X-Y pair.
Pachytene chromomere maps of Chinese hamster autosomes
Authors: Jhanwar S.C. , Chaganti R.S.K.
Published: May 2008

A standard chromomere map of the Chinese hamster autosomes at pachytene has been prepared and presented. Comparison of bands on somatic chromosomes and chromomeres on meiotic chromosomes revealed a close correspondence between the two. Chromosome contraction from prophase to metaphase at mitosis and early to late pachytene at meiosis lead, due to coalescence, to the recognition of decreasing numbers of bands and chromomeres. As expected, a greater number of chromomeres could be recognized at pachytene than could Giemsa- and Quinacrine-positive bands at somatic metaphase.
Polymorphic nature of nucleolus organizer regions in fishes
Authors: Foresti F. , Almeida Toledo L.F. , Toledo F° S.A.
Published: May 2008

An analysis of the nucleolar organizer region (NOR) by silver staining of five species of the order Gymnotiformes, Gymnotus carapo, Apteronotus albijrons, Sternopygus macrurus, Eigenmannia virescens, and Eigenmannia sp., is reported. The five species presented only one pair of homologs bearing NORs. In G. carapo, A. albijrons, and S. macrurus the silver-stained NORs were present as small black dots over the chromosomes. In E. virescens, the short arm of one of the largest chromosome pairs was entirely stained with silver. Eigenmannia sp. presented an intraspecific variability of the NOR-bearing pair and an increase in the length of this region, the larger one being about six times the size of the smaller. These findings suggest that an increase in the number of ribosomal genes in the NORs of certain species occurred during the evolution of this group.
Formation of chromosome-type aberrations at the first cleavage after MMS treatment in late spermatids of mice
Authors: Tanaka N. , Katoh M. , Iwahara S.
Published: May 2008

Male mice were treated with graded doses of methyl methanesulfonate (MMS) and mated with untreated female mice during the six to ten days after treatment. The nature of the primary lesions induced in late spermatids was investigated by analysing the types and rates of chromosome aberrations in the first cleavage metaphases. The chromosome aberrations recovered at the first cleavage were predominantly of the chromosome-type. Their frequency increased exponentially with increasing dose of MMS. The results suggested that the nonenzymatic conversion of DNA containing alkylated bases to new damage, possibly strand breaks, during the maturation and storage of sperm was primarily responsible for the enhancement of the frequency of chromosome-type aberrations.
Dose and concentration dependence of chromosome aberrations in human cells and the combined action of radiation and chemical mutagens
Authors: Bochkov N.P. , Yakovenko K.N. , Voskoboiynik N.I.
Published: May 2008

This paper describes a study of the combined effect of gamma-rays and N, N’, N’’triethylenethiophosphoramide (thiotepa) on unstimulated leukocytes. The sequence of treatments and the interval between them (up to 4 h) do not affect the frequency of chromosome aberrations. In observing the combined effect of the mutagens, interaction of their effects was noted; however, quantitatively it does not differ significantly from the sum of their separately induced effects. Therefore, the elementary additivity model can be used to predict combined effects in the case of weak interactions. Exponential models for estimating combined effects based on a stepwise regression procedure are presented.
Chromosomal mutations in human populations
Authors: Evans H.J.
Published: May 2008

Chromosomal mutations in human populations are of two forms: those which arise in germ cells, or their precursors, and result in constitutional chromosomal anomalies in offspring—and contribute to a substantial proportion of congenital abnormality and heritable diseases in man; and those that arise in somatic cells and which may result in cell killing, loss or diminution of cell function, or contribute to the processes involved in neoplastic transformation. The incidence of somatic chromosome mutations (aberrations) can be readily ascertained from studies on peripheral blood lymphocytes. Data on their prevalence in cells from “normal” populations are presented. The incidence of aberrations is increased in people exposed to mutagens so that changes in aberration frequency provide a means for monitoring population exposure. This is illustrated by studies on populations exposed to ionising radiations and to various chemical mutagens including cigarette smoke. An alternative approach to the cytogenetical assessment of chromosome damage is described, in which the incidence of lymphocytes resistant to cell killing by 8-azaguanine is utilised. The frequencies of such resistant cells are shown to increase with increasing age of the individual, and it is further demonstrated that their incidence is increased, in a dose-dependent fashion, when cells are exposed in vitro to X-rays or chemical mutagens.
Chromosome aberrations as a measure of mutagenesis: cytogenetic extrapolation from animal to man
Authors: Léonard A. , Fabry L. , Deknudt G. , Decat G.
Published: May 2008

A reevaluation of the factors considered to affect the chromosomal sensitivity of mammalian peripheral blood lymphocytes has been made on the basis of some recent experiments using the harlequin-staining method to distinguish the first from subsequent divisions. Observations on human lymphocytes show that the mixing up of first and second or third cell cycle cells cannot explain all the variability between the experiments performed without bromodeoxyuridine labeling. Establishing a uniform methodology is also not likely to eliminate all causes of variation. Similar heterogeneity is observed for other mammalian species. Provided comparisons are restricted to results obtained within the same laboratory, some estimation of the relative sensitivity of chromosomes from different species is, however, possible.
Role of chromosomal mutation in the development of cancer
Authors: Sasaki M.
Published: May 2008

An overview is presented of current profiles of human and experimental animal tumors, paying special attention to nonrandom chromosome changes and their implications, including our own data and views on human leukemias and murine lymphomas.
The use of surface spreading in the pachytene analysis of a human t (Y;17) reciprocal translocation
Authors: Laurent C. , Chandley A.C. , Dutrillaux B. , Speed R.M.
Published: May 2008

This paper describes a human Y;17 reciprocal translocation in an azoospermic male ascertained through infertility. Meiotic studies made on both air-dried and surface-spread preparations are reported in addition to a somatic chromosome analysis carried out by high resolution R-banding on pro-metaphase chromosomes. The possible cause of spermatogenic disturbance in Y-autosome heterozygotes is discussed.
The chromosomes of the Hadada ibis and comments on the karyotype evolution in Threskiornithidae (Aves, Ciconiiformes)
Authors: Capanna E. , Civitelli M.V. , Geralico C.
Published: May 2008

The karyotype of Hagedashia hagedash differs from that of the other ibises karyotyped and introduces further karyotypic variability within the family Threskiornithidae. This variability is in contrast with the generalized karyotypic uniformity of birds and the karyotypic identity displayed by the family Ciconidae, which is closely related to the ibises. A discussion is presented of parameters of ethological structure of the populations that can, in some cases, allow chromosomal rearrangement to be fixed, thereby enhancing ongoing speciation phenomena in the Aves class.
Cytotaxonomy of the Ciconiiformes (Aves), with karyotypes of eight species new to cytology
Authors: de Boer L.E.M. , van Brink J.M.
Published: May 2008

Somatic karyotypes of 13 species of ciconiiform birds, Phoenicopterus ruber chilensis, Phoeniconaias minor, Cochlearius cochlearius, Geronticus eremita, Threskiornis molucca, T. spinicollis, Balaeniceps rex, Ciconia ciconia, C. nigra, Euxenura maguari, Xenorhynchus asiaticus, Ephippiorhynchus senegalensis, and Leptoptilos crumeniferus are presented. The chromosomes of eight of these species are described in detail for the first time. Of special interest are a case of structural heterozygosity in a male B. rex and remarkably low diploid numbers in C. nigra (2n = ca 52) and L. crumeniferus (2n = ca 52).
Chromosomal mutations in pigs derived from X-irradiated semen
Authors: Fries R. , Stranzinger G.
Published: May 2008

Chromosomal mutations (eight translocations, two pericentric inversions, one paracentric inversion) were found in 8 of 30 phenotypically normal pigs derived from semen irradiated at 800 rads. There were no chromosomal mutations detected in pigs derived from semen irradiated at 600 rads. A summary of the spontaneous and induced cases of chromosomal mutations in the family Suidae suggests that chromosomes 1 and 15 are more often involved in rearrangements.
Construction of cloned libraries from RNA of human fetal tissues
Authors: Kurnit D.M. , Wentworth B.M. , De Long L. , Villa-Komaroff L.
Published: May 2008

We have constructed libraries of recombinant DNA plasmids containing sequences complementary to polyadenylated RNA from a variety of human midtrimester fetal tissues. The bacterial colonies containing these plasmids have been grown and replicated on nitrocellulose filters in a manner that facilitates permanent storage, rapid screening, and transportability to other laboratories. We screened a portion of the library for the presence of repetitive sequences and found that approximately 20% of the clones contain repetitive sequences. We have also shown that some clones contain nonrepetitive sequences. Pools of recombinant cDNA-containing plasmids devoid of repetitive sequences have been constructed to permit the chromosomal localization of a variety of actively transcribed sequences. The construction of such large, tissue-specific clone banks should facilitate the direct isolation, mapping, and characterization of normal and abnormal human genes.
The effect of exogenous DNA insertion at a chromosomal region containing rDNA
Authors: Henderson A.S. , Robins D.
Published: May 2008

We have previously shown that exogenous DNA may be incorporated into host cell chromosomes following DNA-mediated gene transfer (transformation). Discrete chromosomal changes often accompany the integration event. In this study, the effect of integration of DNA that codes for human growth hormone into a region containing ribosomal DNA in rat chromosomes was investigated. The results show that insertion of exogenous DNA results in the inactivation of the ribosomal DNA and a partial deletion of ribosomal DNA sequences.
Nucleoli, micronucleoli, and nucleolus-like structures in human oocytes at meiotic prophase I studied by the silver-NOR technique
Authors: Hartung M. , Keeling J.W. , Patel C. , Bobrow M. , Stahl A.
Published: May 2008

Meiotic nuclei preparations obtained from human fetal ovaries were studied with the silver-NOR technique. At leptotene, the NOR’s were located at the periphery of the nucleoli. The mean number of NOR’s per nucleus was 6.4. Moreover, 2–12 micronucleoli, each containing an Ag-positive zone, were observed. At pachytene, each nucleolus was divided into two zones, one of which was Ag-positive. The mean number of Ag-positive zones was 2.1 per nucleus. The subterminal region of the short arm of nucleolar bivalents was in contact with the argyrophilic nucleolar zone. In most cells, micronucleoli were dispersed between the bivalents. A single rounded body which stained heavily with silver was consistently observed. At early diplotene, the NOR’s separated, appearing again as distinct rounded Ag-positive structures embedded in the peripheral part of the nucleoli. The silver-stained round body was still visible. Eight to twelve micronucleoli were observed. At a more advanced stage of diplotene, the number of micronucleoli increased, varying from 20 to 50 per nucleus. These observations suggest that the micronucleoli, already visible at the leptotene stage, are the morphological expression of an early transcription of amplified rDNA. The biological significance of the Ag-positive round body remains obscure, but the consistency of its appearance suggests that it has a specific function somehow related to nucleolar proteins.