Abnormalities of chromosome No. 1: significance in malignant transformation.

Studies of human hematologic malignancies have provided sufficient data not only for the identification of nonrandom abnormalities of whole chromosomes, but also for determination of the specific chromosome regions involved. In clonal aberrations leading to an excess of chromosome No. 1, or a partial excess of No. 1, trisomy for bands 1q25 to 1q32 was noted in the myeloid cells obtained from every one of 35 patients who had various disorders, such as acute leukemia, polycythemia vera, or myelofibrosis. Similar chromosome changes were a consistent finding in various solid tumors as well. This rearrangement was not the result of a particularly fragile site in that region of the chromosome, since the break points in reciprocal translocations that involve No. 1 occurred almost exclusively in the short arm. The nonrandom chromosome changes found in neoplastic cells can now be correlated with the gene loci on these chromosomes or chromosome segments as an attempt is made to identify specific genes that might be related to malignancy.     

Interrelations Between Seeds and Associated Fruiting Structures During Their Development in Trifolium subterraneum L.

Developing burrs of T. subterraneum (cv. Daliak) were subjectedto dark and light treatments in experiments conducted in a controlledtemperature glasshouse with day/night air temperatures of 18/13°C. Post fertilization development of burr components wasfollowed and the effect of removal of seeds or sterile calyoeson the development of the remaining burr components studied. Peduncle elongation took place mainly between days 0 (anthesis)and 7, when the burr would normally have buried. Seed developmentwas completed by day 42. Pod walls attained near maximum weightat about day 22. The perianth increasd in weight between days12 and 22 due to enlargement of the calyx. Sterile calyces wereprduced continuously until day 42. The pattern of burr develompentwas similar in both dark and light, but the weight of the maincomponents were considerably reduced in the light treatment. Normal peduncle development depended on the presence of at leastone seed in the inflorescence. Pod walls did not develop, neitherdid the perianth enlarge unless these structures were associatedwith a developing seed. In the absence of seeds fewer sterilecalyces were produced in the dark treatment and fewer stillwere produced in the light, indicating a direct inhibitory effectof light on the production of sterile calyces. Within matureburrs the weight of pod walls and sterile calyces was closelyrelated to the weight of seeds. Removal of sterile calyces reducedseed production but interpretation of this effect is not clear. Trifolium subterraneum L., fruit development, seed production     

On the variation in chromosome number in Potamogeton pectinatus L.

To determine whether the large morphological differences that occur between populations of Potamogeton pectinatus L. have a genetic basis, the chromosome numbers of several populations were counted. Although several numbers were determined, no correlation between different numbers and populations could be established. The number was always close to 2n = 78, which is that most recorded for P. pectinatus in the literature. However, although some aberrant counts can probably be ascribed to incorrect interpretations of the preparations, some cells undoubtedly contain more than 78 chromosomes. Since the chromosomes of P. pectinatus are very small it is difficult to distinguish between “normal” and “B-chromosomes”, which may be the cause of the higher numbers.     

Interrelations of global macroecological patterns in wing and thorax size,sexual size dimorphism,and range size of the Drosophilidae

Support for macroecological rules in insects is mixed, with potential confounding interrelations between patterns rarely studied. We here investigate global patterns in body and wing size, sexual size dimorphism and range size in common fruit flies (Diptera: Drosophilidae) and explore potential interrelations and the predictive power of Allen's, Bergmann's, Rensch's and Rapoport's rules. We found that thorax length (r² = 0.05) and wing size (r² = 0.09) increased with latitude, supporting Bergmann's rule. Contrary to patterns often found in endothermic vertebrates, relative wing size increased towards the poles (r² = 0.12), a pattern against Allen's rule, which we attribute to selection for increased flight capacity in the cold. Sexual size dimorphism decreased with size, evincing Rensch's rule across the family (r² = 0.14). Yet, this pattern was largely driven by the virilis–repleta radiation. Finally, range size did not correlate with latitude, although a positive relationship was present in a subset of the species investigated, providing no convincing evidence for Rapoport's rule. We further found little support for confounding interrelations between body size, wing loading and range size in this taxon. Nevertheless, we demonstrate that studying several traits simultaneously at minimum permits better interpretation in case of multiple, potentially conflicting trends or hypotheses concerning the macroecology of insects.     

Interrelations of NAD and adenosine transformation in the rat liver

The interrelationship of NAD and adenosine (inosine) conversions in the rat liver is investigated. The ratio of products of NAD+ conversions (ADP-ribose, inosine, hypoxanthine and ribose phosphates) are established. AMP and adenosine are not detected, which indicates an availability of different activities of the corresponding enzymes. It is shown that under conditions of the high inorganic phosphate concentration (33 mM) ribose-1-phosphate, formed in the purine nucleoside phosphorylase reaction, is accumulated due to the phosphoribomutase inhibition, but in the presence of NAD+ the utilization of ribose phosphate increases significantly. Nicotinamide inhibits the NAD+-glycohydrolase reaction in the system containing 33 mM phosphate, NAD+ and adenosine and simultaneously it lowers the utilization of ribose.     

Alteration by centric fission of the diploid chromosome number in Vicia faba L.

An individual with a diploid chromosome complement of 2n=14 instead of 2n=12 is deseribed for the broad bean Vicia faba L. This karyotypic deviation resulted from centromere splitting of the wildtype metacentric satellite chromosome pair as demonstrated by Giemsa banding pattern. It is the first case of centric fission observed in this species. Our data support the hypothetic mechanism of Robertsonian rearrangements suggested by Holmquist and Dancis (Genetica 52–53: 151–163, 1980).     

On the selection for the modal chromosome number in Chinese hamster cells

Chinese hamster cell lines have a strong tendency to maintain as modal chromosome number the euploid one characteristic of the species. By following the evolution of karyotypes in cloned subpopulation it has been possible to show that these pseudodiploid constitutions are not simply established due to a selective advantage but they are actually generated in populations where pseudodiploid classes had been absent. The possible role of the mitotic apparatus in keeping and restoring the euploid number is discussed.     

X chromosome inactivaton and SV40 transformation of mammalian cells.

Five embryonic mouse cultures and one human fibroblast culture were transformed with SV40. The cultures were studied cytologically to see if the normal pattern of sex chromosome replication was maintained in SV40 transformed cells. Characteristic late replication patterns were observed for both the X and Y chromosomes, and there was no evidence for loss of the inactive X chromosome, even in cells with 4 or more X chromosomes. The human line was heterozygous at two X-linked loci and a clonal analysis showed that the expression of X-linked genes was not affected by SV40 transformation.     

Analysis of the chromosome number in cells by flow cytometry

A new flow-cytometric method is described that permits analysis of the number of chromosomes of individual cells. Preliminary stained mitotic cells are passed through a specially designed flow chamber in which they are destroyed just before passing through the focused laser beam of the flow cytometer. Signals from chromosomes of the destroyed cells are counted, and the results are represented as a distribution of the number of chromosomes in the cells. The method may be applied for the detection of relatively rare cells with abnormal numbers of chromosomes in biological and clinical research.     

Genetic relations among basil taxa (Ocimum L.) based on molecular markers, nuclear DNA content, and chromosome number

Twenty-eight basil accessions including six Ocimum species and six botanical varieties or cultivars of O. basilicum were studied using molecular markers, nuclear DNA content, and chromosome counting. This is the first study reporting the nuclear DNA content in the genus Ocimum. The results supported the existence of more infrageneric groups within the genus. The section Ocimum was further divided into two separate clades. The first clade contained the accessions belonging to different botanical varieties and cultivars of O. basilicum as well as O. minimum, indicating that the separate species rank of O. minimum was not justified. The second clade, comprising O. americanum, O. africanum, and two O. basilicum var. purpurascens accessions, could represent a set of allopolyploid species sharing some common parental genomes. O. tenuiflorum was the most divergent species according to genetic distance; it had the smallest genome size, organized in small chromosomes, and the lowest chromosome number. Chromosome data obtained in our research could indicate that the basic chromosome number for species belonging to section Ocimum is x = 12. This suggestion implies that species belonging to O. basilicum clade are tetraploids, while species belonging to O. americanum clade are hexaploids. It seems that the basic chromosome number for O. gratissimum could be x = 10 and for O. tenuiflorum x = 9. The differences in genome size and chromosome number among Ocimum species indicate that evolution of their genomes was accompanied by both sequence deletion/amplification and chromosome rearrangements and polyploidization.     

The Interrelations among Stochastic Pacing,Stability, and Memory in the Heart

Low pacing variabilty in the heart has been clinically reported as a risk factor for lethal cardiac arrhythmias and arrhythmic death. In a previous simulation study, we demonstrated that stochastic pacing sustains an antiarrhythmic effect by moderating the slope of the action potential duration (APD) restitution curve, by reducing the propensity of APD alternans, converting discordant to concordant alternans, and ultimately preventing wavebreaks. However, the dynamic mechanisms relating pacing stochasticity to tissue stability are not yet known. In this work, we develop a mathematical framework to describe the APD signal using an autoregressive stochastic model, and we establish the interrelations between stochastic pacing, cardiac memory, and cardiac stability, as manifested by the degree of APD alternans. Employing stability analysis tools, we show that increased stochasticity in the ventricular tissue activation sequence works to lower the maximal absolute eigenvalues of the stochastic model, thereby contributing to increased stability. We also show that the memory coefficients of the autoregressive model are modulated by pacing stochasticity in a nonlinear, biphasic way, so that for exceedingly high levels of pacing stochasticity, the antiarrhythmic effect is hampered by increasing APD variance. This work may contribute to establishment of an optimal antiarrhythmic pacing protocol in a future study.     

The Interrelations among Stochastic Pacing,Stability, and Memory in the Heart

Low pacing variabilty in the heart has been clinically reported as a risk factor for lethal cardiac arrhythmias and arrhythmic death. In a previous simulation study, we demonstrated that stochastic pacing sustains an antiarrhythmic effect by moderating the slope of the action potential duration (APD) restitution curve, by reducing the propensity of APD alternans, converting discordant to concordant alternans, and ultimately preventing wavebreaks. However, the dynamic mechanisms relating pacing stochasticity to tissue stability are not yet known. In this work, we develop a mathematical framework to describe the APD signal using an autoregressive stochastic model, and we establish the interrelations between stochastic pacing, cardiac memory, and cardiac stability, as manifested by the degree of APD alternans. Employing stability analysis tools, we show that increased stochasticity in the ventricular tissue activation sequence works to lower the maximal absolute eigenvalues of the stochastic model, thereby contributing to increased stability. We also show that the memory coefficients of the autoregressive model are modulated by pacing stochasticity in a nonlinear, biphasic way, so that for exceedingly high levels of pacing stochasticity, the antiarrhythmic effect is hampered by increasing APD variance. This work may contribute to establishment of an optimal antiarrhythmic pacing protocol in a future study.     

Recombination,chromosome number and eusociality in the Hymenoptera

Extraordinarily high rates of recombination have been observed in some eusocial species. The most popular explanation is that increased recombination increases genetic variation among workers, which in turn increases colony performance, for example by increasing parasite resistance. However, support for the generality of higher recombination rates among eusocial organisms remains weak, due to low sample size and a lack of phylogenetic independence of observations. Recombination rate, although difficult to measure directly, is correlated with chromosome number. As predicted, several authors have noted that chromosome numbers are higher among the eusocial species of Hymenoptera (ants, bees and wasps). Here, we present a formal comparative analysis of karyotype data from 1567 species of Hymenoptera. Contrary to earlier studies, we find no evidence for an absolute difference between chromosome number in eusocial and solitary species of Hymenoptera. However, we find support for an increased rate of chromosome number change in eusocial taxa. We show that among eusocial taxa colony size is able to explain some of the variation in chromosome number: intermediate‐sized colonies have more chromosomes than those that are either very small or very large. However, we were unable to detect effects of a number of other colony characteristics predicted to affect recombination rate – including colony relatedness and caste number. Taken together, our results support the view that a eusocial lifestyle has led to variable selection pressure for increased recombination rates, but that identifying the factors contributing to this variable selection will require further theoretical and empirical effort.     

Interrelations among children,parents, premedication,and anaesthetists in paediatric day stay surgery.

OBJECTIVE--To investigate the incidence of difficulties associated with parental presence during the induction of anaesthesia in children and the influence of premedication with special reference to vomiting after papaveretum. DESIGN--Mixed factual and multiple choice questionnaire completed by medical and nursing staff and parents during and after admission. SETTING--Teaching hospital with regional paediatric general surgical unit where parental presence during induction of anaesthesia is long established. PATIENTS--151 Children aged 1-14 years who had not previously undergone surgery attending with parents for day stay general surgical procedures. INTERVENTION--Children were randomly allocated to receive no premedication (group 1), oral diazepam elixir (0.3 mg/kg) (group 2), or intramuscular papaveretum with hyoscine (0.3 mg/kg with 0.006 mg/kg) (group 3). No other modification to established day stay routine was made. RESULTS--No major problems were associated with the presence of parents during the induction of anaesthesia. Only 10 of the 141 parents who accompanied their child caused some difficulty, and five became distressed. Premedication with both diazepam and papaveretum resulted in sedation but did not ease induction of anaesthesia. Papaveretum greatly reduced pain and distress immediately after the operation, pain and discomfort being observed in only 15% of children (7/48) compared with 66% (27/41) in group 1 and 49% (22/45) in group 2. Papaveretum, however, must be given intramuscularly, and nurses observed that the children preferred being given premedication orally to intramuscularly. In addition, the incidences of nausea and vomiting were significantly higher in the postoperative ward and at home with papaveretum, although no patient who had been given the drug was nauseous or vomited in the recovery area. The incidences of nausea in group 3 were 62% (31/50) and 57% (27/47) in the postoperative ward and at home, respectively, v 21% (7/33) and 14% (4/29) in group 1 and 13% (5/38) and 14% (5/37) in group 2; the incidences of vomiting in group 3 were 60% and 43% in the postoperative ward and at home, respectively, v 18% and 7% in group 1 and 11% and 11% in group 2. Finally, neither the administration or otherwise of premedication nor the drug given affected the children''s or parents'' perception of day care surgery. CONCLUSIONS--Difficulties with parents in anaesthetic rooms were not common or severe. Premedication provides preoperative sedation and papaveretum improves the immediate postoperative course but the incidences of nausea and vomiting after operation are higher with its use than without.     

我国境内常春藤叶婆婆纳染色体计数及其生态学意义

常春藤叶婆婆纳 ( Veronica hederaefolia L.)是地中海周缘国家的重要农田杂草 ,近期由境外传入我国江苏、浙江地区。对该种的染色体计数表明 ,我国境内的这一新外来杂草染色体数目从 1 8、36、54、32和 2 2均有 ,分别占总计数的 2 3.91 %、1 .0 9%、2 .1 7%、69.57%和 3.2 6%。新传入我国境内的常春藤叶婆婆纳是一种具有潜在危害的农田杂草。     

Genome size and chromosome number in the New Zealand species of Schoenus (Cyperaceae)

Schoenus (Cyperaceae) has holocentric chromosomes. Chromosome numbers were counted and nuclear DNA amounts were measured for all the New Zealand species of the genus. Chromosome numbers ranged from 2n = 8 to c. 2n = 90. Two chromosome races, with 2n = 28 and 2n = 56, were found in S. pauciflorus. Flow cytometry using propidium iodide‐stained nuclei was used to measure genome size. A 14.8‐fold variation in 2C DNA content was found, with values ranging from 1.33 to 19.71 pg/2C nucleus. Phylogenetic trees based on sequence variation in the internal transcribed spacer (ITS) region of the 45S ribosomal DNA locus were constructed using several phylogenetic models to reveal possible evolutionary relationships among the New Zealand Schoenus spp. and a sample of Australian Schoenus spp. Analysis revealed heterogeneity of chromosome number, size and DNA C value within clades. Meiosis in four species showed only bivalent formation at metaphase I. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 555–564.