Influences of habitat fragmentation by damming on the genetic structure of masu salmon populations in Hokkaido, Japan

Dam construction dramatically influences riverine ecosystems, with habitat fragmentation being one of the most serious impacts. This habitat fragmentation is particularly relevant for anadromous species such as salmonids. We examined the effects of habitat fragmentation on masu salmon (Oncorhynchus masou) populations in Hokkaido, Japan. Specifically, we sampled from 15 locations located above and below a dam region in the Uryu River system, and analyzed the genetic structure of the populations using 10 microsatellite loci. No indication of a significant reduction in genetic diversity, estimated by allelic richness and heterozygosity, was observed within the above-dam region compared to the below-dam region. However, we also found that reducing the number of alleles had occurred within the above-dam region. The analysis of molecular variance and multidimensional scaling analysis indicated significant genetic differentiation between regions and within each region. A significant relationship between genetic and geographic distance was observed in the below-dam region, while no signal of isolation by distance was detected in the above-dam region. This study suggests a possibility of ongoing loss of alleles coinciding with habitat fragmentation caused by anthropogenic environmental changes such as water-level regulation, which negatively impacts genetic structure.     

Acipimox enhances spontaneous growth hormone secretion in obese women

We hypothesized that a high circulating free fatty acid (FFA) concentration is involved in the pathogenesis of hyposomatotropism associated with obesity. To evaluate this hypothesis, 10 healthy premenopausal women (body mass index 33.8 +/- 1.0 kg/m(2)) were studied in the follicular phase of their menstrual cycle at two occasions with a time interval of at least 8 wk, where body weight remained stable. Subjects were randomly assigned to treatment with either acipimox (an inhibitor of lipolysis, 250 mg orally 4 times daily) or placebo in a double-blind crossover design, starting 1 day before admission until the end of the blood sampling period. Blood samples were taken during 24 h with a sampling interval of 10 min for assessment of growth hormone (GH) concentrations, and GH secretion was estimated by deconvolution analysis. Identical methodology was used to study GH secretion in a historical control group of age-matched normal weight women. GH secretion was clearly blunted in obese women (total daily release 66 +/- 10 vs. lean controls: 201 +/- 23 mU x l(Vd)(-1) x 24 h(-1), P = 0.005, where l(Vd) is lite of distribution volume). Acipimox considerably enhanced total (113 +/- 50 vs. 66 +/- 10 mU x l(Vd)(-1) x 24 h(-1), P = 0.02) and pulsatile GH secretion (109 +/- 49 vs. 62 +/- 30 mU x l(Vd)(-1) x 24 h(-1), P = 0.02), but GH output remained lower compared with lean controls. Further analysis did not show any relationship between the effects of acipimox on GH secretion and regional body fat distribution. In conclusion, acipimox unleashes spontaneous GH secretion in obese women. It specifically enhances GH secretory burst mass. This might mean that lowering of systemic FFA concentrations by acipimox modulates neuroendocrine mechanisms that orchestrate the activity of the somatotropic ensemble.     

Altered setting of the pituitary-thyroid ensemble in hypocretin-deficient narcoleptic men

Hypo- or hyperthyroidism is associated with autonomic disorders. We studied Fos expression in the medullary dorsal motor nucleus of the vagus (DMV), nucleus tractus solitarii (NTS), and area postrema (AP) in four groups of rats with different thyroid states induced by a combination of drinking water and daily intraperitoneal injection for 1-4 wk: 1) tap water and vehicle; 2) 0.1% propylthiouracil (PTU) and vehicle; 3) PTU and thyroxine (T4; 2 microg/100 g); and 4) tap water and T4 (10 microg/100 g). The numbers of Fos immunoreactive (IR) positive neurons in the DMV, NTS, and AP were low in euthyroid rats but significantly higher in the 4-wk duration in hypothyroid rats, which were prevented by simultaneous T4 replacement. Hyperthyroidism had no effect on Fos expression in these areas. There were significant negative correlations between T4 levels and the numbers of Fos-IR-positive neurons in the DMV (r = -0.6388, P < 0.008), NTS (r = -0.6741, P < 0.003), and AP (r = -0.5622, P < 0.004). Double staining showed that Fos immunoreactivity in the DMV of hypothyroid rats was mostly localized in choline acetyltransferase-containing neurons. Thyroid hormone receptors alpha1 and beta2 were localized in the observed nuclei. These results indicate that thyroid hormone influences the DMV/NTS/AP neuronal activity, which may contribute to the vagal-related visceral disorders observed in hypothyroidism.     

Periprocedural routines of coronary angioplasty--extreme diversity with unrevealed consequences

Our objective was to evaluate the current trends of coronary angioplasty periprocedural care in the state of Israel. PTCA technology has undergone through some major developments and refinements, which have yielded new algorithms and routines. With this shift of paradigms, some of the periprocedural routines (these include medications and dosing before, during and after the procedure, as well as the handling of anti-coagulation, femoral sheath removal and the extent of patient monitoring post-PTCA) have been partially re-established. In order to assess trends in periprocedural care, we elected to analyze the current state of practice in the state of Israel. A questionnaire was sent to every cardiac catheterization laboratory in Israel that performs PTCA. An authorized senior cardiologist representing the laboratory submitted the information required for our survey. A nurse-to-nurse telephone questionnaire was conducted simultaneously to cross-examine the validity of the data. All centers submitted results. The average heparin dose for PTCA varied between 5000 and 15 000 units, ACT was monitored routinely by some and not at all by others, post-PTCA heparin administration was routinely administered by some institutions and not by others, and the mean femoral sheath dwell time ranged from 4 to 18 h. Post-PTCA cardiac monitoring varied from 6 to more than 24 h. Some institutions prescribed to all patients nitrates, calcium channel blockers and low-molecular-weight heparin, while others did not. We conclude that there is profound variability in the periprocedural routines that may translate into a significant cost increase, patient discomfort, a prolonged monitoring and hospital stay, and potential patient morbidity. We suggest that these routines should be critically evaluated, and that if they do not contribute to the procedural success and patient well-being they should be abandoned.     

Resource and habitat sharing by the stoplight parrotfish,Sparisoma viride, a Caribbean reef herbivore

Synopsis We compare the vertical distribution, substrate preferences, grazing behaviour and social interactions of the stoplight parrotfish,Sparisoma viride, with that of other scarids at a fringing reef off Bonaire (Netherlands Antilles). Earlier reports thatS. viride only displays territorial behaviour against conspecifics are confirmed by the non-aggressive nature of this parrotfish and the low time expenditure on interactions with other herbivores. The vertical distribution ofS. viride is largely identical to that of several other scarids, acanthurids and pomacentrids, whose ranges may completely coincide withS. viride territories. Comparison of the substrate use of the five most common scarids inside a singleS. viride territory yields no evidence of food partitioning. We suggest that the lack of interspecific territorial behaviour inS. viride is explained by the inability to economically defend a territory against all potential food competitors. Factors that may favour territory sharing between herbivores are fine-scale resource partitioning and shared defence, both of which would reduce the costs of territorial life. However, more detailed investigation of herbivore food selection is required before definite conclusions can be drawn.     

Role of macrophage colony-stimulating factor in the differentiation and expansion of monocytes and dendritic cells from CD34+ progenitor cells

The present study focused on whether it is possible to expand monocytic cells from CD34⁺ progenitor cells by using macrophage colony-stimulating factor (M-CSF) in the absence and presence of mast cell growth factor (MGF) and IL-6. It was demonstrated that CD34⁺ cells differentiate without expansion to functional mature monocytic cells in the presence of M-CSF or combinations of M-CSF plus IL-6 and MGF. A different response pattern was observed for the number of clonogenic cells. The addition of IL-6 or both IL-6 and MGF to M-CSF containing cultures resulted in significant higher numbers of colony-forming unit-macrophage (CFU-M) as tested in clonogenic and³H-thymidine assays. Furthermore, M-CSF plus both IL-6 and MGF appeared to be the most potent combination to preserve the monocytic precursor in cell suspension culture assays. These results indicate that IL-6 and MGF in conjunction with M-CSF affect CD34⁺ cells especially at precursor level without distinct effect on the more mature stages. Secondly we studied whether M-CSF is only critical for the monocytic lineage or also affects dendritic cell (DC) development. Indeed, we were able to culture CD83⁺ DC from CD34⁺ progenitor cells in the presence of M-CSF in conjunction with TNF-α, IL-4, and MGF although their absolute number is almost threefold lower than the number of CD83⁺ cells yielded from GM-CSF plus TNF-α, IL-4, and MGF stimulated CD34⁺ cells.     

Minimum Incidence of Adult Invasive Pneumococcal Disease in Blantyre,Malawi an Urban African Setting: A Hospital Based Prospective Cohort Study

Invasive pneumococcal disease causes substantial morbidity and mortality in Africa. Evaluating population level indirect impact on adult disease of pneumococcal conjugate vaccine (PCV) programmes in infants requires baseline population incidence rates but these are often lacking in areas with limited disease surveillance. We used hospital based blood culture and cerebrospinal fluid surveillance to calculate minimal incidence of invasive pneumococcal disease in the adult (≥15 years old) population of Blantyre, a rapidly growing urban centre in southern Malawi, in the period preceding vaccine introduction. Invasive pneumococcal disease incidence in Blantyre district was high, mean 58.1 (95% confidence interval (CI): 53.7, 62.7) per 100,000 person years and peaking among 35 to 40 year olds at 108.8 (95%CI: 89.0, 131.7) mirroring the population age prevalence of HIV infection. For pneumococcal bacteraemia in urban Blantyre, mean incidence was 60.6 (95% CI: 55.2, 66.5) per 100,000 person years, peaking among 35 to 40 year olds at 114.8 (95%CI: 90.3, 143.9). We suspected that our surveillance may under-ascertain the true burden of disease, so we used location data from bacteraemic subjects and projected population estimates to calculate local sub-district incidence, then examined the impact of community level socio-demographic covariates as possible predictors of local sub-district incidence of pneumococcal and non-pneumococcal pathogenic bacteraemia. Geographic heterogeneity in incidence was marked with localised hotspots but ward level covariates apart from prison were not associated with pneumococcal bacteraemia incidence. Modelling suggests that the current sentinel surveillance system under-ascertains the true burden of disease. We outline a number of challenges to surveillance for pneumococcal disease in our low-resource setting. Subsequent surveillance in the vaccine era will have to account for geographic heterogeneity when evaluating population level indirect impact of PCV13 introduction to the childhood immunisation program.