Skewed inactivation of an X chromosome deleted at the dystrophin gene in an asymptomatic mother and her affected daughter

A girl with severe Becker muscular dystrophy and apparently normal chromosomes had a heterozygous deletion for exons 51, 52, and 53 of the dystrophin gene. This deletion was transmitted by her mother, who was unaffected. To differentiate the normal and the deleted X chromosomes, fluorescence in situ hybridization (FISH) was applied to metaphase chromosomes, using probes for both exons 51 and 52, which are only 388 and 113 base pairs long, respectively. FISH signals were observed in one or both chromatids of one chromosome, but never on both chromosomes, suggesting the lack of hybridization on the deleted X chromosome. Using 5-bromodeoxyuridine incorporation to differentiate the late (inactive) and the early replicating (active) X chromosomes, 77% of the signals were observed on the active X chromosomes in the mother. This percentage was only 18% in the daughter, suggesting that skewed inactivation of the X chromosomes was responsible for the phenotypic differences.     

Effectiveness of a program to improve hypertension screening in primary care.

OBJECTIVE: To evaluate the effectiveness of a program to improve hypertension screening practices in primary care. DESIGN: Retrospective quasi-experimental study. SETTING: Two hospital-based family medicine centres (FMCs). PATIENTS: In the study FMC, two study groups of randomly selected adult patients: 425 who visited the FMC before implementation of the screening improvement program (from Apr. 1, 1983, to Mar. 31, 1984) and 418 who visited it afterward (from Apr. 1, 1986, to Mar. 31, 1987). These patients were matched with 392 and 442 control patients respectively seen during the same time frames at the second FMC. INTERVENTIONS: Educational sessions for physicians to standardize blood pressure measurement and knowledge of the recommendations from the Canadian Hypertension Society on hypertension screening and diagnosis, and specific operational incentives to improve hypertension screening, including a reference guide placed in each physician''s office, a coloured form for recording blood pressure measurements placed in every patient''s chart and a follow-up and recall card file. MAIN OUTCOME MEASURE: Frequency of blood pressure measurements recorded in patient charts. RESULTS: The hypertension screening rate was 60% per year in the study group before program implementation and 79% in the study group afterward; the corresponding rates in the two control groups were 72% and 59% (p < 0.0001). Patients were more likely to be screened if they visited the physician for a periodic health examination than for other problems (e.g., psychosocial or dermatologic) and if they had a scheduled appointment rather than no appointment. Physician characteristics that were positive predictors of screening were low age, female sex and payment on a salary basis. CONCLUSION: Physician education and incentives are effective in improving hypertension screening practices in hospital-based FMCs without incurring additional costs or other use of resources. Further evaluation of such a program should be undertaken in other primary care settings.     

Toward a more holistic ecology,and science: the contribution of H.T. Odum

Conclusion For the abovementioned reasons, and with all due respect to the scholarship of Mansson and McGlade, who display a deep knowledge of thermodynamics and ecology, I cannot agree that Odum's use of energy concepts is wholly discredited. Refinements from microscopic thermodynamics may not have been faithfully carried along in his work, but does ecology really need these? Remember — the meal test.Having tussled with ecological complexity myself, I stand in awe of this man who has faced up to what most ecologists today are trying to deny — intractable, crushing, defeating complexity. If Odum has provided some of the first shaky stepping stones across this gulf, that's enough.I can finish by quoting from ny Festschrift paper again:It is often said of scientists who make unusual contributions against the grain of their disciplines that they are ahead of their time. In H.T. Odum's case, with maximum power, energy-circuit diagrams, emergy, transformity, and energy value the linchpins of a whole new theory of ecology, and paradigm within systems ecology, this can certainly be stated without hesitation. But in this instance, it is also possible to turn the observation around and suggest that ecology-as-science is behind its time, lagging the curve of need foreseen decades ago by a more pragmatic ecology-as-ethic and-concern. The growing man-and-environment tension, fostered by so-far unabatable growth of populations, technologies and economies, demands a science that incises complexity, finds the essence of systemness, and produces quantitative methods capable of moulding this essence to meet the imperatives of the new environmentalism. H.T. Odum has not, perhaps, provided a definitive theory to do this; no one could right now. But, he has given us an intriguing mix of science, art and religion that stands as one of the singular legacies of 20th-century ecology, pointing the way toward a new ecology of complexity that must, I think from need, fully arise in the 21st century. His time has been behind him.     

Rank relations among sisters in semi-free-ranging Barbary macaques (Macaca sylvanus)

Although semi-free-ranging Barbary macaque females are able to outrank older females from lower-ranking matrilines (matrilineal rank acquisition), they do not systematically outrank their older sisters, as is known to be the case for semi-free-ranging rhesus monkeys (Macaca mulatta) and Japanese macaques (Macaca fuscata). We test the hypothesis that differences in the support received by younger sisters against their older sisters and against older lower-ranking females might account for this interspecific difference. Thirty-one sister dyads, members of a group of 109 Barbary macaques living at La Montagne des Singes, France, were observed during 16 months. The results indicate that (1) all females were dominant to their younger sisters, and the latter were never observed to challenge their older sisters; (2) younger sisters received as much kin support against their older sisters as against older lower-ranking females; (3) only very young females received support from their kin against their older sisters; (4) younger sisters received much more support from nonkin females against lower-ranking females than against their older sisters; and (5) Barbary macaque females appear to be supported against their older sisters less frequently than rhesus macaque females are. We conclude that the lack of nonkin support is the main factor accounting for the failure of younger sisters to outrank their older sisters in Barbary macaques. Initially this might result from kin support not being sufficient to induce younger sisters to challenge and to solicit support against their older sisters.     

L’Equipement chromosomique du spermatozoïde

Cytogenetics of human sperm chromosomes has been developped by few laboratories during the last decade, in order to investigate dysfuncitons of meiosis in normal men and in carriers of chromosomal abnormalities. On the basis of pooled data, it can be established that normal men produce almost 10% of abnormal spermatozoa, including a majority of structural aberrations (6.5%). Frequency of hyperhaploïdies, resulting from chromosome malsegregations, seems to be equally distributed among all chromosome groups. A study of in vivo recently irradiated patients demonstrates that despite a high incidence of multiple rearrangements, the sperm fertilizing ability is not reduced. Segregation of additional chromosomes can also be studied in fertile carriers; such as study has demonstrated that, in a mosaic patient, 47 XXY germ cells are able to complete meiosis. Finally the major application of the technique consists in direct segregation analysis of structural chromosome rearrangements. The sperm of such carriers exhibits a higher proportion of unbalanced spermatozoa than generally expected in offsprings.     

Mouse oocyte maturation is affected by lithium via the polyphosphoinositide metabolism and the microtubule network

The incubation of mechanically denuded mouse oocytes in medium containing LiCl delayed both germinal vesicle breakdown (GVBD) and polar body extrusion in a dose-dependent and reversible manner. When myo-inositol alone was added to the culture medium, we observed that it accelerated GVBD and increased the rate of polar body extrusion, whereas, when combined with LiCl, the normal timing of GVBD was recovered. In the same way, when inositol trisphosphate (InsP₃) was microinjected into the ooplasma, we observed an important improvement of the rate of GVBD, as compared to control oocytes, and prevention of lithium inhibition. However, neither myo-inositol nor InsP₃ were able to rescue totally the oocytes from the negative effect of lithium on polar body extrusion. Moreover, lithium induced some important changes in microtubule and chromosome organizations. Before extrusion of the first polar body, the reduction of the spindle size or the appearance of short individualized chromosomes dispersed around a large aster of microtubules were often observed, whereas, after polar body extrusion, the spindle appeared smaller and chromosomes were often trapped in the midbody. Thus lithium affects mouse oocyte maturation at two different levels: GVBD and polar body extrusion. Whereas the former seems to be affected via polyphosphoinositide turnover, the latter is InsP₃-independent and seems to be influenced negatively via underdevelopment of microtubular structures. © 1994 Wiley-Liss, Inc.     

The Presence of (+)-S-Adenosyl-l-Methionine in the Rat Brain and Its Lack of Effect on Phenylethanolamine N-Methyltransferase Activity

Abstract: (+)-S-Adenosyl- l -methionine [(+)-SAM] was isolated from rat brain and was quantified by HPLC followed by UV spectrophotometric measurements and by ¹H-NMR. Its estimated ratio in brain is 3% of total SAM. Because of its commercial unavailability, (+)-SAM was also prepared from chemically synthesized SAM by separation of the two diastereoisomers on a preparative reverse-phase Nucleosil C8 column. The (+) diastereoisomer thus obtained was then assayed in vitro both as an inhibitor and a substrate of phenylethanolamine N -methyltransferase. Enzymatic activity was measured by HPLC analysis. It was shown that (+)-SAM has no effect on phenylethanolamine N -methyltransferase activity; therefore, it is unlikely that (+)-SAM plays any possible role in regulation of adrenaline synthesis in the brain.     

Immunohistochemical detection of strain-specific major histocompatibility complex class I antigens in paraffin-embedded rat osteochondral tissue

Summary An immunohistochemical method using formalin-fixed, paraffin wax-embedded sections is described for detecting strain-specific major histocompatibility complex class I antigens in knee-joint tissue from DA and Lewis strains of rat. The fixed osteochondral tissues were additionally decalcified in formic acid before processing for paraffin wax embedding. For immunohistochemistry, two monoclonal antibodies, one specific for DA class I allele RT1Aa and the other for Lewis class I allele RT1A1, were used together with the avidin-biotin immunoperoxidase procedure. It was necessary to use strain-specific normal rat serum as a diluent for the antibodies to suppress cross-strain recognition. DA-specific antibody stained positively only on DA rat sections, not on Lewis rat sections, and Lewis-specific antibody stained positively only on Lewis rat sections, and not on DA. Positive staining was localized in the bone marrow, osteochondral cells and endothelium. We propose that the use of a decalcification medium may have enhanced the immunoreactivity of the tissue. The method described can be used on sections of allografts from the two strains of rat to assess morphologically the extent of cellular replacement of the graft by the host's cells.     

Casein kinase II in signal transduction and cell cycle regulation

Molecular and Cellular Biochemistry - Casein kinase II is a protein serine/threonine kinase that is ubiquitously distributed in eukaryotes. Molecular cloning studies and protein sequence analysis...     

Polarized distribution of γ interferon-stimulated MHC antigens and transferrin receptors in a clonal cell line isolated from Fisher rat thyroid (FRT cells)

Summary The fine structure of single identified muscle fibers and their nerve terminals in the limb closer muscle of the shore crab Eriphia spinifrons was examined, using a previous classification based on histochemical evidence which recognizes a slow (Type-I) fiber and three fast (Type-II, Type-III, Type-IV) fibers. All four fiber types have a fine structure characteristic of crustacean slow muscle, with 10–12 thin filaments surrounding each thick filament and sarcomere lengths of 6–13 m. Type-IV fibers have sarcomere lengths of 6 m while the other three types have substantially longer sarcomeres (10–13 m). Structural features of nerve terminals revealed excitatory innervation in all four fiber types but inhibitory innervation in Type-I, Type-II, and Type-III fibers only. Thus fibers with longer sarcomeres receive the inhibitor axon but those with shorter sarcomeres do not. Amongst the former, synaptic contact from an inhibitory nerve terminal onto an excitatory one, denoting presynaptic inhibition, was seen in Type-I and Type-II fibers but not in Type-III and Type-IV fibers. Inhibitory innervation of the walking leg closer muscle is therefore highly differentiated: some fibers lack inhibitory nerve terminals, some possess postsynaptic inhibition, and some possess both postsynaptic and presynaptic inhibition.