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PubMed1997

Multicolour FISH detects frequent chromosomal mosaicism and chaotic division in normal preimplantation embryos from fertile patients.

We have used multicolour fluorescent in situ hybridisation (FISH) with DNA probes for chromosomes X, Y and l to analyse spare untransferred cleavage-stage embryos after preimplantation diagnosis to avoid X-linked disease. In total, 93 morphologically normal embryos were available from seven patients (six of proven fertility) who had undergone fourteen in vitro fertilisation (IVF) cycles. The chromosome patterns observed were classified into four groups; normal, abnormal (non-mosaic), mosaic and chaotic (uncontrolled division). Approximately half of the embryos were normal for the chromosomes tested. Two embryos only were aneuploid (non-mosaic) throughout but, after excluding those showing chaotic division, 30% were considered to be chromosomal mosaics. Of these, a minority had arisen because of mitotic non-disjunction or chromosome loss or gain, whereas the majority were ploidy mosaics, with haploidy being the most common. The occurrence of chaotically dividing embryos was strongly patient-related, i.e. some patients had 'chaotic' embryos in repeated cycles, whereas other patients were completely free of this type of anomaly. 'Chaotic' embryos are unlikely to progress beyond implantation. These findings have important implications both for routine IVF and preimplantation genetic diagnosis.

Adult↗

PubMed1998

Assessment of autosome and gonosome disomy in human sperm nuclei by chromosome painting.

Disomy and diploidy frequencies for autosomes 1-22 and the gonosomes were assessed in 299,442 sperm nuclei from four normal fertile men by chromosome painting. This novel approach allowed us to perform a specific and sensitive detection of each chromosome. A minimum of 5000 sperm nuclei per subject were evaluated for each chromosome by dual colour fluorescence in situ hybridization. The disomy rate proved to be similar for all the autosomes (0.24%) and the diploidy rate varied from 0.12% to 0.15%. No interchromosomal or interindividual differences in the frequency of disomic and diploid sperm nuclei were observed between the four subjects. The mean frequency of XX-, YY- and XY-bearing spermatozoa was estimated to 0.17%, 0.17% and 0.32%, respectively. This strategy constitutes a new approach for detecting aneuploidy in human sperm nuclei and suggests an equal repartition of non-disjunction among chromosomes in male gametes.

Adult↗

PubMed2000

Chromosome analysis of blastomeres from human embryos by using comparative genomic hybridization.

Karyotypic studies of aborted fetuses have been used to draw the inference that the proportion of conceptuses with chromosome abnormalities is very high. Fluorescent in situ hybridization (FISH) studies of blastomeres from early cleavage embryos have provided some support for this inference but they are limited to the study of a few chromosomes. We describe the novel application of comparative genomic hybridization (CGH) to the study of numerical and structural abnormalities of single blastomeres from disaggregated 3-day-old human embryos. CGH results were obtained for 63 blastomeres from 12 embryos. Identification of all chromosomes with the exception of chromosomes 17, 19, 20 and 22 was possible. The embryos divided into four groups: (1) embryos with a normal CGH karyotype seen in all blastomeres; (2) embryos with consistent aneuploidy suggesting meiotic non-disjunction had occurred; (3) embryos that were mosaic generally with one or more cells showing aneuploidy for one or two chromosomes but some with cells showing extensive aneuploidy; and (4) one embryo with extensive aneuploidy in all blastomeres. The extensive aneuploidy in group 4 is interpreted as corresponding to the random aneuploidy seen in "chaotic" embryos reported by using interphase FISH. Partial chromosome loss and gain following chromosome breakage was observed in one embryo. Our analysis provides basic biological information on the occurrence of constitutional and post-zygotic chromosome abnormalities in early human embryos. Used in conjunction with embryo biopsy, diagnostic CGH should allow the exclusion of a proportion of embryos that appear normal but that have a poor probability of survival and, therefore, may improve the implantation rate after in vitro fertilization.

Base Sequence↗

PubMed2005

Variation in predation pressure as a mechanism underlying differences in numerical abundance between populations of the poeciliid fish Heterandria formosa.

We explored whether a variation in predation and habitat complexity between conspecific populations can drive qualitatively different numerical dynamics in those populations. We considered two disjunct populations of the least killifish, Heterandria formosa, that exhibit long-term differences in density, top fish predator species, and dominant aquatic vegetation. Monthly censuses over a 3-year period found that in the higher density population, changes in H. formosa density exhibited a strong negative autocorrelation structure: increases (decreases) at one census tended to be followed by decreases (increases) at the next one. However, no such correlation was present in the lower density population. Monthly census data also revealed that predators, especially Lepomis sp., were considerably more abundant at the site with lower H. formosa densities. Experimental studies showed that the predation by Lepomis gulosus occurred at a much higher rate than predation by two other fish and two dragonfly species, although L. gulosus and L. punctatus had similar predation rates when the amount of vegetative cover was high. The most effective predator, L. gulosus, did not discriminate among life stages (males, females, and juveniles) of H. formosa. Increased predation rates by L. gulosus could keep H. formosa low in one population, thereby eliminating strong negative density-dependent regulation. In support of this, changes in H. formosa density were positively correlated with changes in vegetative cover for the population with a history of lower density, but not for the population with a history of higher density. Our results are consistent with the hypothesis that the observed differences among natural populations in numerical abundance and dynamics are caused in part by the differences in habitat complexity and the predator community.

Animals↗

PubMed2004

Maternal uniparental disomy of chromosome 16 in a case of spontaneous abortion.

To investigate the involvement of uniparental disomies (UPDs) in spontaneous abortions, we analyzed in detail the polymorphism of microsatellites on each chromosome in cases of abortion. Of the 52 spontaneous abortions investigated, 25 had a normal karyotype. The polymorphic analysis of these cases revealed that, in the villi from 24 of the 25 cases, biparental patterns were present in informative microsatellites in all autosomes. In the remaining case with a 46,XX karyotype (case 18), however, the informative patterns of the microsatellites of chromosome 16 appeared to be both of maternal origin. The results also showed that the region from the distal end of the short arm to near the middle point of the long arm of chromosome 16 (pter to D16S3107) were heterozygous, and those of the remaining region of the long arm (D16S3018 to qter) were homozygous. That is, this fetus had maternal isodisomy and heterodisomy of chromosome 16, originating from a maternal, meiosis I non-disjunction of dyad 16 that accompanied a crossover at near the middle point of the long arm. The present finding suggests that some UPDs may become a cause for spontaneous abortions.

Abortion, Spontaneous↗

PubMed2001

Evolution of the genomic systems of prokaryotes and its momentous consequences.

The earliest self-reproducing cell on Earth, our common ancestor, was probably as small as present-day bacteria. It gave rise to a very large and durable clone whose descendants must have been the only living occupants of the oceans for about one thousand million years. They reached astronomical numbers of separate, disjunct cells, and synthesized many new genes. Their small volume could not accommodate ever larger genomes and useful new genes replaced resident, less successful sequences, thus increasing diversity and the number of strains with highly specialized, distinct, bioenergetic potentialities. Also, selective pressure favored strains able to participate successfully in division of labor and in the sharing of diverse abilities in mixed communities, counterbalancing the limited capacities of individual genomes. Lateral gene transfer mechanisms appeared and were progressively improved, furthering the development of diversity. The prokaryotes' constructive evolution resulted in the formation of a worldwide web of genetic information, and a global bacterial superbiosystem (superorganism). By contrast, eukaryotic evolution of organisms has been typically Darwinian. Diversification of eukaryotic organisms was, however, considerably enriched and accelerated by symbioses with prokaryotes. The more broadly diversified bioenergetic potential of prokaryotes considerably increased the diversity of eukaryotes. Without their participation, our biosphere would have remained much less diverse and less dynamic. Environmental homeostasis has been maintained all along by guided bacterial evolution.

Evolution, Molecular↗

PubMed2003

Phylogenetic relationships in the genera Zostera and Heterozostera (Zosteraceae) based on matK sequence data.

Phylogenetic analysis of the plastid (chloroplast) DNA matK gene of Zosteraceae species was undertaken. A molecular phylogenetic tree based on matK sequence data showed the monophyly of Heterozostera tasmanica and subgenus Zosterella and did not support the separation of Heterozostera from the genus Zostera. The tree based on matK supported the monophyly of the subgenus Zostera, and showed that Zosteraceae consist of three main groups: Phyllospadix, which is clearly defined by being dioecious; the subgenus Zosterella and Heterozostera; and the subgenus Zostera. Character-state reconstruction of chromosome number and geographic distribution for our molecular phylogenetic tree showed that 2 n=12 is a plesiomorphic character for Zostera and Heterozostera, that the chromosome number was doubled or tripled in two lineages, and that the initial speciation of Zostera and Heterozostera occurred in the Northern Hemisphere. The matK tree showed the close affinity of Z. noltii and Z. japonica, which have disjunct distributions. Zostera marina, which is the only widely distributed species in the subgenus Zostera, also occurring in the northern Atlantic, was shown to be embedded within other subgenus Zostera species.

Biological Evolution↗

PubMed2004

Taxonomic and phytogeographic implications from ITS phylogeny in Berberis (Berberidaceae).

A phylogeny based on the internal transcribed spacer (ITS) sequences from 79 taxa representing much of the diversity of Berberis L. (four major groups and 22 sections) was constructed for the first time. The phylogeny was basically congruent with the previous classification schemes at higher taxonomic levels, such as groups and subgroups. A notable exception is the non-monophyly of the group Occidentales of compound-leaved Berberis (previously separated as Mahonia). At lower levels, however, most of previous sections and subsections were not evident especially in simple-leaved Berberis. Possible relationship between section Horridae (group Occidentales) and the simple-leaved Berberis clade implies paraphyly of the compound-leaved Berberis. A well-known South America-Old World (mainly Asia) disjunctive distribution pattern of the simple-leaved Berberis is explained by a vicariance event occurring in the Cretaceous period. The ITS phylogeny also suggests that a possible connection between the Asian and South American groups through the North American species ( Berberis canadensis or B. fendleri) is highly unlikely.

Asia↗

PubMed2005

Ploidy, geographical distribution and morphological differentiation of Parasenecio auriculata (Senecioneae; Asteraceae) in Japan.

Parasenecio auriculata is a woodland perennial herb widely distributed in Northeastern Asia, constituted by a poorly understood polyploidy with a diploid (2n = 2x = 60) and a tetraploid (2n = 4x = 120). In this study, for a better understanding of the polyploidal evolution, cytogeography and morphological variation were analyzed in Japanese P. auriculata, including two varieties; var. bulbifera endemic to central Hokkaido and var. kamtschatica widely distributed in northern Honshu and Hokkaido. The occurrence of two polyploidal levels was reconfirmed. While var. bulbifera is predominantly tetraploid, var. kamtschatica is comprised of diploid and tetraploid. Morphological variation among 22 quantitative characteristics is continuous and not distinctive among cytotypes or varieties, but plant size tended to be larger in the order, diploid of var. kamtschatica, var. bulbifera, and tetraploid of var. kamtschatica. The cytotype distribution showed a conspicuous geographical pattern. Besides var. bulbifera endemic to the central Hokkaido, the diploid of var. kamtschatica is mainly found in Southern Hokkaido, and the tetraploid has a disjunct distribution in eastern and northern Hokkaido and northern Honshu. Such a geographical pattern is possibly attributable to the differentiation of climatic preference among cytotypes and varieties, and may have been established in association with the climatic cline along the Japanese archipelago.

Analysis of Variance↗

PubMed2006

Status and distribution pattern of black crested gibbon (Nomascus concolor jingdongensis) in Wuliang Mountains, Yunnan, China: implication for conservation.

The western black crested gibbon (Nomascus concolor), or black gibbon, one of the lesser apes (Hylobatidae), is mainly distributed in Yunnan, China. Of the four recognized subspecies, N. c. jingdongensis is endemic to the Wuliang Mountain, central Yunnan, China. Of all the subspecies, this one has the largest population of any black gibbon. However, the data were all based on brief estimates. We carried out an extensive field survey on population and group distribution of the black gibbon in the Wuliang Mountains by use of loud morning songs and interviews with local people. Ninety-eight groups were confirmed and located in the mid-montane range of Wuliang Mountains. More groups are found on the east slope and the southern region than in the west and the north. Gibbons are more disjunctly distributed on the west slope, especially in the northern part. Deforestation in the late 1950s, 1960s and 1970s was the main reason for rapid loss of habitat and population decline. Hunting was another key reason for population decline and, in many cases, the main reason for local extinction.

Animals↗

PubMed2005

Simplified models of the relationship between health and disease.

The concepts of health and disease are crucial in defining the aim and the limits of modern medicine. Accordingly it is important to understand them and their relationship. However, there appears to be a discrepancy between scholars in philosophy of medicine and health care professionals with regard to these concepts. This article investigates health care professionals' concepts of health and disease and the relationship between them. In order to do so, four different models are described and analyzed: the ideal model, the holistic model, the medical model and the disjunctive model. The analysis reveals that each model has its pros and cons, and that health care professionals appear to apply more than one models. Furthermore, the models and the way health care professionals' use them may be helpful for scholars in philosophy of medicine with regard to developing theories and communicating them to health care professionals.

Attitude of Health Personnel↗

PubMed2006

The occurrence of the Japanese species Dinosoma lophiomi Toman, 1973 (Digenea: Hemiuridae) in Lophius piscatorius (Teleostei) from the western Mediterranean.

Hemiurid worms from the stomach of the angler Lophius piscatorius off Corsica are described and considered to belong to a Japanese species, Dinosoma lophiomi Toman, 1973, which was originally described from an Indo-Pacific lophiid host. The apparent disjunctive distribution of this species and apparent differences in the terminal genitalia between the European and Japanese specimens are discussed. This is the first record of Dinosoma Manter, 1934 from the Mediterranean Sea. The validity of diagnostic features of Adinosoma Manter, 1947 is commented upon, and lists of records of species of Dinosoma and digeneans from L. piscatorius in the Western Mediterranean are included.

Animals↗

PubMed1994

Using cuticular hydrocarbon composition to elucidate phylogenies in tick populations (Acari: Ixodidae).

Cuticular hydrocarbon composition is used to explain hypothetical phylogenies among sympatric and allopatric populations of Amblyomma cajennense, A. variegatum and Ixodes ricinus tick species. The method proposed here uses a parsimony analysis of endemicity by disjunct biochemical data (PAEDB) based in the pattern of cuticular hydrocarbons. The advantage of our approach is that information contained in fragments that are not conserved in all the individuals of a populations need not be discarded, and that only patterns of presence/absence are used. In such a way, PAEDB methodology provides a system which traces the pathway of a definite compound through populations, together with data of genetic relationships among specimens.

Animals↗

PubMed1980

Electrocardiographic exercise testing and ambulatory monitoring to identify patients with ischemic heart disease at high risk of sudden death.

Prognostic significance of ambulatory electrocardiographic monitoring and exercise testing was studied in 144 patients with established ischemic heart disease. A follow-up study showed that 10 sudden deaths occurred within 2 years. The univariates most strongly associated with the subsequent occurrence of sudden death included reduced maximal exercise heart rate, exercise-induced frequent ventricular arrhythmias, complex ventricular arrhythmias revealed by 24 hour ambulatory electrocardiographic monitoring and onset of S-T segment depression during exercise testing. Groups of patients at very high and very low risk of sudden death were identified using conjunction and inclusive disjunction of the foregoing variable. The presence of bivariate and trivariate combinations was associated with an increase up to 20-fold in the incidence of sudden death. Patients with the poorest prognosis were those who stopped exercise before achieving a high heart rate and who exhibited either pronounced electrocardiographic abnormalities during stress testing or complex ventricular arrhythmias during ambulatory monitoring. Combinations of exercise variables identified patients at a very high risk of sudden death, whereas combinations of monitoring variables appeared to be preferable for defining groups of patients at very low risk. The results obtained suggest that the two methods carry different prognostic information and, therefore, may complement each other in identifying potential victims of sudden cardiac death.

Adult↗

PubMed1988

Advanced manufacturing technology: The implications for human resources strategies.

In recent years, the human factors community has devoted much attention to specifying the conditions required for successful exploitation of advanced manufacturing technology (AMT). Through their accumulated experience and detailed analyses, practitioners have developed prescriptions for action which, it can be predicted with a high degree of confidence will maximise the chances of successful AMT application. Equally remarkable, however, has been the - at best - partial and incomplete application of these prescriptions as a means of improving industrial performance. This paper considers the reasons why companies have, to a large extent, failed to incorporate human factors thinking in their strategies, and why corporate performance has suffered as a result. The paper locates some reasons for the low utilisation of human factors expertise in a disjunction between, on the one hand, the ways in which chief executives see the world and articulate their concerns, and, on the other hand, the way in which human factors experts formulate and advocate the application of their proposals. Some examples of the problem are discussed, and specific remedies proposed.

Journal Article↗

PubMed1977

Cytochemical localization of acetylcholine receptors at the neuromuscular junction by means of horseradish peroxidase-labeled alpha-bungarotoxin.

The cytochemical localization of acetylcholine (ACh) receptors at the neuromuscular junction was investigated with a procedure utilizing alpha-bungarotoxin (alpha-BtX) labeled directly with horseradish peroxidase (HRP). Following incubation of tissues in the conjugate and reaction for peroxidase, activity was observed on the junctional folds of the motor endplate. A uniform layer of reaction product approximately 15 nm thick occurred over the apical portions of the junctional folds. Membranes at the bases of the synaptic cleft showed only small amounts of reaction product. Non-junctional regions of the muscle fiber were unreactive. Activity was also observed in the membrane of the axon facing the muscle surface, often including the axolemma overlying the "active zones" of the nerve terminal. Such presynaptic activity was still evident on nerve terminals disjuncted from the synapse by enzymatic treatment prior to incubation in the conjugate. This localization indicates the possible presence of presynaptic ACh receptors within the axolemma. In muscle denervated for 7-12 days, motor endplates were reactive and parajunctional sarcolemma showed slight activity, but most extrajunctional regions contained no obvious accumulations of reaction product. Activity at all sites was prevented by preincubation of tissues in native alpha-BTX prior to incubation in the conjugate and reaction for HRP. This procedure represents a simple and convenient method for the high resolution localization of ACh receptors.

Animals↗

PubMed1986

Somatosensory representation of the cerebellar climbing fiber system in the rat.

The climbing fiber responses of 542 Purkinje cells were isolated in the vermal and intermediate zones of lobules II to VI of the rat cerebellum. Mechanical stimulation successfully elicited 53% of the isolated climbing fiber responses, whereas the remaining units were unresponsive to any stimulation employed. Of the units elicited by the stimulation, 34% required cutaneous and 66% required deep stimulation. Some proportion of the representation of each body region required either cutaneous or deep stimulation. The hind-limb had the largest representation and accounted for 55% (160/288) of the units. In contrast, the forelimb was only represented by 10% of the units, the tail by 16%, the face by 11% and the remaining 6% of the units by surface regions of the spine, chest and abdomen. On the basis of their proportional representation of body regions, 3 different cortical areas were distinguished: (1) a medial vermis, which consisted predominantly of unresponsive units; (2) a lateral vermis, which included representations of the extremities, trunk and tail; and (3) the intermediate zone, where the only representation of the face was evident. Within each area, the representations formed a disjunctive pattern of irregularly shaped patches and areas of overlap. In comparison with the climbing fiber organization of the cat, the medial vermal unresponsive zone and the patch-like representations of various body surfaces in the rat were similar to the cat, but the proportional representation of various body surfaces and effective stimulus modality were different, which may reflect morphological and behavioral differences between the species.

Afferent Pathways↗

PubMed1982

Principal component analysis of pain-related cerebral potentials to mechanical and electrical stimulation in man.

Single trial event-related cerebral potentials (ERPs) in response to skin stimuli of various intensities and qualities in man were investigated in respect to their nociceptive information content. Electrical constant current stimuli (20 msec, 2 - 8 mA) and mechanical force controlled stimuli (20 msec, 0.8 - 3.2 N) were applied to the tip of the left middle finger. Four intensities of each stimulus quality were given, each intensity appearing 40 times in standardized randomized order. EEG segments (between 5 sec before and 500 msec after stimulus onset) were subjected to computer analysis. ERP wave form was shown to depend upon the amount of alpha waves in the prestimulus EEG. For analysis, only subjects with low power in the alpha band were selected. Principal component analysis was applied to all single trial ERPs measured using the variance-covariance matrix of association. Six principal components (PCs) were extracted accounting for about 90% of total variance. Five of the extracted PCs had well located loading maxima: PC1 (50 - 80 msec), PC4 (140 - 160 msec), PC3 (200 - 250 msec), PC4 (280 - 360 msec), PC5 (400 - 500 msec); PC6 appeared polyphasic. Analysis of variance of the mean PC scores revealed that one PC (PC1) discriminated between quality, and 4 PCs (PC1 - PC4) between quantity of stimulation. Eliminating effects of stimulus intensity resulted in two PCs (PC2, PC4) which distinguished exclusively between non-pain and pain. PCA applied to disjunctive subsets of ERPs, corresponding to the different experimental conditions, yielded practically identical sets of PCs, such that no specific ERP component emerged when pain was reported.

Adult↗