无精症患者染色体脆性位点的研究

目的：探讨染色体脆性位点在无精症形成过程中的作用,了解其相关因素,为进行病因学研究和采取干预措施打下基础。方法：本文用低叶酸低胸苷的培养基,并用5-氟尿嘧啶脱氧核糖核酸苷（FUDR）和咖啡因双诱导淋巴细胞染色体脆性位点表达。结果：实验组染色体脆性位点的频率为13.20%;对照组为4.85%,两组对比差异非常显著。染色体脆性位点的分布两组基本一致。结论：无精症与染色体脆性位点频率增高有关,与脆性位点分布关系不大。     

骨肉瘤患者染色体不稳定性和脆性部位表达的研究

对48例骨肉瘤患者和36例正常人外周血淋巴细胞染色体不稳定性和脆性部位表达进行了研究,发现患者染色体裂隙、断裂点、异常细胞率和脆性部位表达率均显著高于正常对照组,且脆性部位3p~(14),7q~(32).11q~(13),13q~(13)在半数以上病例中表达。这些位点与某些癌基因同位或毗邻。染色体不稳定性增加和脆性部位的过度表达可解释骨肉瘤患者有较高的肿瘤遗传易感性。     

TSPY, the Candidate Gonadoblastoma Gene on the Human Y Chromosome, has a Widely Expressed Homologue on the X - Implications for Y Chromosome Evolution

TSPY, a candidate gene for a factor that promotes gonadoblastoma formation (GBY), is a testis-specific multicopy gene family in the male-specific region of the human Y (MSY) chromosome. Although it was originally proposed that male-specific genes on the Y originated from a transposed copy of an autosomal gene (Lahn & Page 1999b), at least two male-specific genes (RBMY and SRY) descended from a formerly recombining X-Y identical gene pair. Here we show that a TSPY homologue with similar gene structure lies in conserved positions, close to SMCX, on the X chromosome in human (TSPX ) and mouse (Tspx). TSPX is widely expressed and subject to X inactivation. TSPX and TSPY therefore evolved from an identical gene pair on the original mammalian sex chromosomes. This supports the hypothesis that even male-specific genes on the Y chromosome may have their origin in ubiquitously expressed genes on the X. It also strengthens the case for TSPY as a candidate for GBY, since independent functional studies link TSPX to cell cycle regulation.     

Chromosome abnormalities and rare fragile sites detected in azoospermia patients

Summary We have examined constitutional chromosome abnormalities and fragile sites in 40 patients with azoospermia. Chromosome abnormalities were found in four cases. Three cases showed a deletion of the long arm of the Y chromosome 46,X,del(Yq) and the other case had a ring of G group chromosome 46,XY,r(G). In a rare fragile sites test, four fragile site carriers were detected and three rare autosomal fragile sites were identified; fra(8)(q24.1), fra(11)(p15.1), and fra(17)(p12). The expression of these fragile sites were induced specifically by AT-specific DNA ligands, such as distamycin A and Hoechst 33258. In addition, one patient was found to be the case of double ascertainment of fragile sites, fra(8)(q24.1) and fra(17)(p12). The overall frequency of distamycin A-inducible fragile sites in azoospermia patients appeared to be higher than those reported for Japanese healthy subjects and cancer patients. However, no significant relation among fragile sites, clinical and histological findings has been detected so far.     

Light and electron microscopic morphology of the temporomandibular joint in growing and mature crab-eating monkeys (Macaca fascicularis): the condylar calcified cartilage.

Summary In an attempt to show maturational alterations in the calcified cartilage, mandibular condyles of four growing and four adult male monkeys (Macaca fascicularis) were studied using light microscopy as well as transmission and scanning electron microscopy. All specimens were initially fixed by perfusion in the presence of ruthenium red. For examination of the hard tissue surfaces in the scanning electron microscope, uncalcified tissues were removed with sodium hypochlorite. In growing animals, almost the entire hard tissue surface in the joint region of the condyle was formed by calcified cartilage, while in adult animals, calcified cartilage was confined to load-bearing regions. In growing animals, the appearance of the calcified cartilage surface suggested a continuously advancing mineralizing front similar to that seen in the epiphyseal plate. Chondrocytes mostly exhibited a terminal stage of hypertrophy, and seemed to die and get lost through vascular invasion and subsequent endochondral ossification. In adult animals, most of the calcified cartilage surface appeared comparatively stable, and resembled the tidemark of articular cartilage. Chondrocytes were usually small and appeared viable. However, on the adult condyles, there were always circumscribed islands where chondrocytes and the pattern of mineralization resembled those seen in growing animals. In these regions, prominent chondroclastic activity indicated extensive articular remodelling. These observations suggest that at the end of somatic growth, condylar calcified cartilage undergoes considerable maturation from a type reminiscent of hyaline growth cartilage to a type resembling articular cartilage. Concomitantly, chondrocytes appear to change their developmental program, in that they stop enlarging and lose their commitment to death. However, they may be able to retain, or switch back to, a more immature stage, in case there is need for extensive articular remodelling.     

Conservation of aphidicolin-induced fragile sites in Papionini (Primates) species and humans

Fragile sites are considered structural features of mammalian chromosomes and a commonly repeated hypothesis is that they are evolutionarily conserved. We tested this hypothesis by establishing the subchromosomal homology of regions harbouring fragile sites in the chromosomes of humans, Macaca fascicularis (MFA) and Mandrillus sphinx (MSP). We delineated the interspecific homology of chromosome bands expressing aphidicolin-induced fragile sites of homologues to human chromosomes 1, 3, 5, 7, 18 and X by the comparative FISH of human BAC and YAC clones. Notably, two YAC clones known to span human chromosome regions containing fragile sites were shown to also span fragile sites in macaques and mandrills. The present comparative BAC/YAC mapping data represent, up to now, the most precise evidence of fragile site conservation during primate evolution. This revised version was published online in July 2006 with corrections to the Cover Date.     

Chromosome evolution in the annual killifish genus Cynolebias and mitochondrial phylogenetic analysis

Extensive chromosome variation involving Robertsonian and non-Robertsonian changes were proposed to explain chromosomal evolution within killifishes of the aplocheiloid group belonging to the order Cyprinodontiforms. In the present work we describe the karyotypes of four Cynolebias species and analyze chromosome changes by means of mitochondrial phylogenetic studies, including 10 taxa of this genus. Diploid numbers varied from 48 to 44 and the number of chromosome arms from 50 to 54. Molecular phylogenetic analyses allow us to corroborate previous hypothesis about chromosome evolution in aplocheiloid fishes. The tree topology based on a combined dataset of mitochondrial cytochrome b and 12S genes shows that recent cladogenetic events within the genus Cynolebias could have occurred by allopatric or in-situ differentiation involving chromosomal rearrangements. Our analyses of approximately 10% of mitochondrial genome can be helpful in determining these recent cladogenetic events but it showed limited phylogenetic resolution at intermediate levels of divergence. This can be explained in part by the high levels of DNA sequence divergence (ranging from 0.015 to 0.245) detected at intrageneric level. Different methodological approaches suggest that chromosomal changes in Cynolebias have occurred during their differentiation, supporting the hypothesis that the unresolved basal polytomy could be the result of rapid speciation events, like a true star polytomy.     

Foregut cyst of the oesophageal wall in a cynomolgus monkey (Macaca fascicularis)

Congenital oesophageal cysts of foregut origin are rare in animals and human beings. This report describes a case in a 4-year-old cynomolgus monkey with no clinical symptoms. The cyst, which was located within the oesophageal submucosal tissue near the mid-point of the oesophagus, was lined with pseudostratified ciliated epithelium and had a thin layer of submucosal tissue. The cyst was surrounded by a smooth muscle layer which was partly intermingled with the circular muscle layer of the oesophagus. The muscularis mucosae of the oesophagus was not shared with the cyst wall. Simple tubular glands were present, opening into the cyst lumen. No communication between the cyst lumen and the oesophagus was observed. Cartilaginous tissue, which is a diagnostic feature of bronchogenic cysts, was not identified in the cyst wall. On the basis of the histopathological features, a foregut cyst of the oesophagus was diagnosed.     

Evolution of Genome Organizations of Squirrels (Sciuridae) Revealed by Cross-Species Chromosome Painting

With complete sets of chromosome-specific painting probes derived from flow-sorted chromosomes of human and grey squirrel (Sciurus carolinensis), the whole genome homologies between human and representatives of tree squirrels (Sciurus carolinensis, Callosciurus erythraeus), flying squirrels (Petaurista albiventer) and chipmunks (Tamias sibiricus) have been defined by cross-species chromosome painting. The results show that, unlike the highly rearranged karyotypes of mouse and rat, the karyotypes of squirrels are highly conserved. Two methods have been used to reconstruct the genome phylogeny of squirrels with the laboratory rabbit (Oryctolagus cuniculus) as the out-group: (1) phylogenetic analysis by parsimony using chromosomal characters identified by comparative cytogenetic approaches; (2) mapping the genome rearrangements onto recently published sequence-based molecular trees. Our chromosome painting results, in combination with molecular data, show that flying squirrels are phylogenetically close to New World tree squirrels. Chromosome painting and G-banding comparisons place chipmunks (Tamias sibiricus ), with a derived karyotype, outside the clade comprising tree and flying squirrels. The superorder Glires (orde Rodentia + order Lagomorpha) is firmly supported by two conserved syntenic associations between human chromosomes 1 and 10p homologues, and between 9 and 11 homologues.     

Evolution of dosage compensation

In polytene chromosome squashes from the fruit flyDrosophila melanogaster, the single, dosage-compensated X chromosome in males can be distinguished from the autosomes by the presence of an isoform of histone H4 acetylated at lysine 16, H4.Ac16. We have used H4.Ac16 as a marker to examine the evolving relationship between dosage compensation and sex chromosome composition in species ofDrosophila with one (D. melanogaster), two (D. pseudoobscura) or three (D. miranda) identifiable X chromosome arms. In each case, we find that H4.Ac16 is distributed as discrete, closely spaced bands along the entire length of each X chromosome, the only exception being the X2 chromosome ofD. miranda in which a terminal region constituting about 10% of the chromosome by length is not labelled with anti-H4.Ac16 antibodies. We conclude that, with this exception, dosage compensation extends along the X chromosomes of all three species. AsD. pseudoobscura andD. miranda diverged only about 2 Mya, the spread of dosage-compensated loci along X2 has been rapid, suggesting that regional changes rather than piecemeal, gene-by-gene, changes may have been involved.accepted for publication by H. C. Macgregor     

Cytological examination and cellular composition of bone marrow in healthy, adult, cynomolgus monkeys (Macaca fascicularis)

The purpose of this study was to evaluate the cellular composition of the bone marrow of cynomolgus monkeys (Macaca fascicularis). Femoral bone marrow smears from 23 healthy, adult animals (11 males and 12 females) were examined. For each animal, three femoral bone marrow smears were prepared immediately after euthanasia and stained with May-Grünwald-Giemsa. On two of the three smears available, and for each of these smears, a 500-cell differential count was performed and the myeloid: erythroid (M:E) ratio established. The M:E ratio for males varied from 0.67∶1.00 to 1.85∶1.00 with a mean of 1.03∶1.00 and for females from 0.67∶1.00 to 1.63∶1.00 with a mean of 1.02∶1.00. The mean percentage of granulocytic, lymphocytic, plasmacytic and erythroid series was 47.60, 5.44, 1.45 and 46.05% for males and 47.28, 5.12, 1.49 and 46.28% for females. No significant differences were noted between males and females. All cell lines were well represented and showed normal maturation in both sexes. Megakaryocytes were adequate in number and morphology in all animals. Cynomolgus monkeys showed a bone marrow composition similar to rhesus monkeys (Macaca mulatta). Cytological examination of bone marrow was found to be a simple and rapid procedure, well suited to the toxicological research environment. It provided excellent information on cell distribution, morphology and maturation of the haematopoietic system.     

Meiosis in Holocentric Chromosomes: Orientation and Segregation of an Autosome and Sex Chromosomes in Triatoma infestans (Heteroptera)

The meiotic behaviour of the X chromosome and one autosomal pair of the heteropteran Triatoma infestans was analysed by means of C-banding plus DAPI staining. At first metaphase, the X univalent is oriented with its long axis parallel to the equatorial plate, which suggests a holocentric interaction with the spindle fibres. After this initial orientation, kinetic activity is restricted to one of both chromatid ends. The election of the active chromatid end is random and it is independent of the end selected in the sister chromatid. At second metaphase, the X and Y chromatids associate side by side forming a pseudobivalent. After that, the kinetic activity is again restricted to either of both chromosomal ends in a random fashion. At first metaphase, the fourth autosomal bivalent shows two alternative random orientations depending on the chromosome end showing kinetic activity (DAPI positive or opposite). At second metaphase, half bivalents are oriented with their long axis parallel to the equatorial plate. Three different segregation patterns are observed. The kinetic activity can be localised: (i) in the end with the DAPI signal (46.9%), (ii) in the opposite end (44.6%) or (iii) in one DAPI-positive end in one chromatid and in the opposite end in the other one (8.5%). The existence of the last pattern indicates that the same end can show kinetic activity during both meiotic divisions. Our results provide new information on the comparative meiotic behaviour of autosomes and sex chromosomes in holocentric systems.     

Chromosome evolution and improved cytogenetic maps of the Y chromosome in cattle, zebu, river buffalo, sheep and goat

Comparative FISH-mapping among Y chromosomes of cattle (Bos taurus, 2n = 60, BTA, submetacentric Y chromosome), zebu (Bos indicus, 2n = 60, BIN, acrocentric Y chromosome but with visible small p-arms), river buffalo (Bubalus bubalis, 2n = 50, BBU, acrocentric Y chromosome), sheep (Ovis aries, 2n = 54, OAR, small metacentric Y chromosome) and goat (Capra hircus, 2n = 60, CHI, Y-chromosome as in sheep) was performed to extend the existing cytogenetic maps and improve the understanding of karyotype evolution of these small chromosomes in bovids. C- and R-banding comparison were also performed and both bovine and caprine BAC clones containing the SRY, ZFY, UMN0504, UMN0301, UMN0304 and DYZ10 loci in cattle and DXYS3 and SLC25A6 in goat were hybridized on R-banded chromosomes by FISH. The main results were the following: (a) Y-chromosomes of all species show a typical distal positive C-band which seems to be located at the same region of the typical distal R-band positive; (b) the PAR is located at the telomeres but close to both R-band positive and ZFY in all species; (c) ZFY is located opposite SRYand on different arms of BTA, BIN, OAR/CHI Y chromosomes and distal (but centromeric to ZFY) in BBU-Y; (d) BTA-Y and BIN-Y differ as a result of a centromere transposition or pericentric inversion since they retain the same gene order along their distal chromosome regions and have chromosome arms of different size; (e) BTA-Y and BBU-Y differ in a pericentric inversion with a concomitant loss or gain of heterochromatin; (f) OAR/CHI-Y differs from BBU-Y for a pericentric inversion with a major loss of heterochromatin and from BTA and BIN for a centromere transposition followed by the loss of heterochromatin.     

Melatonin promotes sleep in three species of diurnal nonhuman primates

Nocturnal melatonin secretion is concurrent with consolidated sleep episodes in diurnal mammals and physiological melatonin levels can promote sleep onset in humans and in pigtail macaques. In order to further investigate the effects of melatonin treatment on sleep parameters in diurnal nonhuman primates, three macaque species have been studied: Macaca nemestrina, Macaca fascicularis, and Macaca mulatta. Sleep was assessed using continuous actigraphic recording of motor activity in animals maintained under 12:12-h light/dark cycle. Oral doses of melatonin (5-320 microg/kg) were administered 2 h before lights-off time, with 5- and 10-microg/kg doses resulting in physiological circulating melatonin levels (31-95 pg/ml). The effects of melatonin administration were similar in three species studied and included significantly earlier sleep onset time and longer sleep period time, with no difference in time of awakening, following administration of both physiological (5-10 microg/kg) and pharmacological (20-320 microg/kg) doses. While low melatonin doses (5-20 microg/kg) did not significantly affect nighttime sleep efficiency, higher pharmacological doses reduced sleep efficiency and increased sleep fragmentation at night, and reduced spontaneous daytime locomotor activity. Daily administration of a 5-microg/kg dose for 4 weeks or gradually escalating melatonin doses (5-320 microg/kg over a 3-week period) did not result in the development of tolerance or sensitization to the effect of melatonin on sleep initiation or sleep period. These data affirm that sleep-promoting effects of melatonin observed in humans are also typical for diurnal primates. They also suggest that physiological and pharmacological melatonin levels might produce different effects on sleep efficiency and that nonhuman primates can serve as adequate animal model for studying the mechanisms of melatonin's action on sleep and performance.     

Immunohistochemical localization of acid-sensing ion channel 2 (ASIC2) in cutaneous Meissner and Pacinian corpuscles of Macaca fascicularis

Acid-sensing ion channel 2 (ASIC2) is a member of the degenerin/epithelial sodium channel superfamily, presumably involved mechanosensation. Expression of ASIC2 has been detected in mechanosensory neurons as well as in both axons and Schwann-like cells of cutaneous mechanoreceptors. In these studies we analysed expression of ASIC2 in the cutaneous sensory corpuscles of Macaca fascicularis using immunohistochemistry and laser confocal-scanner microscopy. ASIC2 immunoreactivity was detected in both Meissner and Pacinian corpuscles. It was found to co-localize with neuron-specific enolase and RT-97, but not with S100 protein, demonstrating that ASIC2 expression is restricted to axons supplying mechanoreceptors. These results demonstrate for the first time the presence of the protein ASIC2 in cutaneous rapidly adapting low-threshold mechanoreceptors of monkey, suggesting a role of this ion channel in touch sense.     

Fragile site X chromosomes and X-linked mental retardation in severely retarded boys in a northern Swedish county. A prevalence study

In an unselected series of 96 severely mentally retarded boys (IQ < 50) born 1959–70 in a northern Swedish county, six had a fragile site on the distal end of the X chromosome (FraXq 28). The prevalence of the fragile X syndrome in severely retarded boys was 6 %. Next to trisomy 21, this fragile X syndrome appears to be the most common single cause of severe mental retardation in boys.     

The Consequences of a Non-uniform Tension Across Kinetochores: Lessons From Segregation of Chromosomes in the Permanent Translocation Heterozygote Oenothera

The alternate (zigzag) configuration of the chromosome ring in oenotheras fulfills the requirement of high tension across kinetochores for stability of the configuration and the progression to anaphase. However, also semialternate configurations (two pairs of adjacent kinetochores interspaced among the zigzag) fulfill the requirement of high tension across kinetochores. If only the magnitude of tensile force acting on a kinetochore pair governs the stability of microtubule attachments, the probability of occurrence of the semialternate configurations would be higher than that of fully alternate configurations. Yet the percentage of irregularity in the zigzag configuration is surprisingly low, which means that the semialternate configurations are corrected. The only difference which distinguishes the fully alternate and the semialternate configurations with respect to the tension across kinetochores is that the tension across a kinetochore alternating with its neighbors is rather uniformly distributed over the kinetochore, while there is a gradient of the tension in the kinetochore having a non-alternating neighbor, with low tension on the side of this neighbor. Apparently, a low tension across a part of a kinetochore brings about correction of its attachment to microtubules. This hypothesis fits with the repeat subunit model of the kinetochore; apparently, each subunit can function autonomously in the tension-governed mechanisms, stabilizing its attachment and controlling the metaphase-to-anaphase transition.     

An autoradiographic study of efferent connections of the globus pallidus in Macaca mulatta

Summary Radioactive amino acids were injected into restricted regions of the globus pallidus of rhesus macaques to allow identification of the organization and courses of efferent pallidal projections. The previously identified projection of the internal pallidal segment (GPi) to ventral thalamic nuclei showed a topographic organization, with the predominant projection from ventral GPi being to medial and caudal ventralis anterior (VA) and lateralis (VL) and from dorsal GPi to lateral and rostral VA and VL. Pallidal efferent fibers also extended caudally and dorsally into pars caudalis of VL, but they spared the portion of pars oralis of VL shown by others to receive input from the cerebellum. In addition to centromedian labeling in all animals, the parafascicular nucleus was also labeled when isotope was injected into dorsal GPi. The medial route from GPi to the midbrain tegmentum was more substantial than has been shown before, and along this route there was an indication that some fibers terminated in the prerubral region. The projection to the pedunculopontine nucleus was extensive, and fibers continued caudally into the parabrachial nuclei.Pallidal projections to the thalamus seem to be topographically organized but spare thalamic regions that interact with area 4. Caudally directed efferent fibers follow multiple routes and extend more caudally than to the pedunculopontine nuclei.Abbreviations Cd caudate nucleus - CM centromedian nucleus - CT central tegmental tract - DPCS decussation of superior cerebellar peduncle - F fornix - FLM medial longitudinal fasciculus - GPe globus pallidus, pars externa - GPi globus pallidus, pars interna - HbL lateral habenular nucleus - HbM medial habenular nucleus - Is interstitial nucleus - LM medial lemniscus - MD dorsomedial nucleus - PbL lateral parabrachial nucleus - PbM medial parabrachial nucleus - PCS superior cerebellar peduncle - Pf parafascicular nucleus - PPN pedunculopontine nucleus - Put putamen - R reticular nucleus - Rmg red nucleus, pars magnocellularis - Rpc red nucleus, pars parvocellularis - S stria medullaris - SI substantia innominata - SNc substantia nigra, pars compacta - SNr substantia nigra, pars reticulata - St subthalamic nucleus - ST stria terminalis - THI habenulointerpeduncular tract - TM tuberomamillary nucleus - TMT mamillothalamic tract - VA nucleus ventralis anterior - VAmg nucleus ventralis anterior, pars magnocellularis - VAp nucleus ventralis anterior, pars principalis - VI nucleus ventralis intermedius - VLc nucleus ventralis lateralis, pars caudalis - VLm nucleus ventralis lateralis, pars medialis - VLo nucleus ventralis lateralis, pars oralis - VPL nucleus ventralis posterior lateralis - X area X Supported by National Institutes of Health, grant RR00166, Rehabilitation Services Administration, grant 16-P-56818, and PHS grant NS10804     

Chromosomes ofDamaliscus (Artiodactyla,Bovidae): Simple and complex centric fusion rearrangements

G- and C-banded karyotypes ofDamaliscus hunteri, D. lunatus andD. pygargus were compared using the standard karyotype ofBos taurus. Chromosomal complements were 2n=36 inD. lunatus jimela, 2n=38 inD. pygargus phillipsi andD. p. pygargus, and 2n=44 inD. hunteri. The fundamental number in all karyotypes was 60. Among the three species ofDamaliscus, seven autosomal pairs and the X chromosomes were conserved. Y-chromosome differences were attributed to heterochromatic additions or deletions. Banded karyotypes of the two subspecies ofD. pygargus exhibited complete homology. Chromosomal complements ofD. pygargus andD. lunatus differed by a simple centric fusion. However, karyotypes ofD. pygargus andD. lunatus differed fromD. hunteri by numerous centric fusions, several of which were related by monobrachial chain complexes. Between the karyotypes ofD. hunteri andD. pygargus orD. lunatus, there were two chain complexes, one involving five chromosomes (chain V) and the other involving 12 inpygargus (chain XII) or 13 inlunatus (chain XIII). There were also two simple centric fusions betweenD. hunteri andD. lunatus/D. pygargus; acrocentric chromosomes 13, 15, 20 and 22 inD. hunteri were fused as 13;15 and 20;22 inD. lunatus andD. pygargus.accepted for publication by D. Ward     

Cerebral malaria in the rhesus monkey (Macaca mulatta): Light and electron microscopic changes in blood cells and cerebrovascular endothelia

To assess the interaction between the cellular elements of the blood and neurovascular endothelia in cerebral malaria, brain tissue from adult rhesus moneys (Macaca mulatta) infected with a virulent (W1) strain of Plasmodium knowlesi were studied by light and electron microscopical techniques. Light microscopical examination showed sequestration of macrophages and margination of erythrocytes containing late stages of the parasite in the capillaries and venules throughout the brains of the infected monkeys. Brain microvascular lesions (associated with parasitised erythrocytes and macrophage attachment to vascular walls) seen with the electron microscope, were swelling of the endothelial cells, formation of pseudopodia, increased numbers of pinocytotic vesicles and disorganisation of the mitochondria. Parasitised mature erythrocytes and macrophages adhered to the vascular endothelial lining in equal proportions. The endothelial ultrastructural alterations were similar to those described in experimental rodent and in clinical human cerebral malaria.