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PubMed2003

Reproductive barriers between congeneric monogenean parasites (Dactylogyrus: Monogenea): attachment apparatus morphology or copulatory organ incompatibility?

Morphometrical parameters of the attachment apparatus and copulatory organs of 52 Dactylogyrus species parasitizing 17 species of cyprinid fishes were analysed to test for the existence of reproductive barriers among congeneric species. The minimal spanning tree (MST) method was applied in the analyses. The position of "real" parasite communities, based on (1) observed infracommunities, (2) a checklist of parasites for a given host in the morphological space, was compared to the position of randomly generated communities using all Dactylogyrus species. The distribution of species similarity within infracommunities (using both attachment and copulatory measurements) was not significantly different from that obtained by simulation, and this trend was similar for both the checklist and observed infracommunities. When real infracommunities were separated according to host specificity (specialists versus generalists), we found differences reflecting similarities in the shapes of attachment and copulatory organs. Within specialists, more similarities in the shape of the attachment apparatus can be found than within generalists, whereas the similarity in copulatory organ shape seems to be random. When generalists are considered, parasite infracommunities with the greater differences in attachment apparatus are also more different in terms of the shape of their copulatory apparatus. We conclude that specialist parasites possess more similarity in attachment apparatus due to specialisation to their host, whereas the species similarity in copulatory organs within infracommunities exhibits a random pattern, but with the copulatory organs being more variable than the attachment apparatus (which may be due to reproductive isolation). The morphology of the copulatory apparatus seems not to be the single factor explaining reproductive isolation among species.

Animals↗

PubMed2001

Sperm motion analysis in rats treated with adriamycin and its applicability to male reproductive toxicity studies.

Adriamycin (ADR), an anticancer drug which induces testicular toxicity, was administrated to Slc:SD male rats at doses of 0.5, 1.0, and 2.0 mg/kg intravenously once a week for 4 weeks. The males treated with ADR were mated with untreated females, and sperm analyses (motion, count, and morphology) were performed. Sperm motion was analyzed by Hamilton-Thorne Sperm analyzer (HTM-IVOS) to investigate the useful parameters. Copulated females were necropsied at Day 13 of gestation, and reproductive status was evaluated. In ADR-treated groups, the testicular weight was dose-dependently decreased. Associated with this decrease was a depletion of the number of spermatogonia noted histopathologically at all dosage levels. Sperm morphological abnormalities, which were classified as tailless sperm and/or no-hook head sperm, were increased in both the 1.0 and 2.0 mg/kg groups. The males treated with ADR at 1.0 and 2.0 mg/kg had a decreased number of sperms per cauda epididymis. In sperm motion analysis, decreases in the percentage of motile sperm, percentage of progressive sperm, and sperm velocity (straight line velocity and curvilinear velocity) were noted at 2.0 mg/kg. Impaired fertility was noted at 2.0 mg/kg in the form of decreased numbers of implantations and live embryos, and an increased number of pre-implantation losses. In conclusion, ADR induced deterioration of sperm motion and sperm content, which were responsible for the adverse effect on male fertility. The most sensitive indicators to detect male reproductive toxicity induced by ADR were testicular weight and histopathological findings in the testis. Among the parameters generated by HTM-IVOS, the percentage of motile sperm, the percentage of progressive sperm, and sperm velocity are useful for assessing male fertility.

Animals↗

PubMed1997

Dominance and queen succession in captive colonies of the eusocial naked mole-rat, Heterocephalus glaber.

Naked mole-rat colonies exhibit a high reproductive skew, breeding being typically restricted to one female (the 'queen') and one to three males. Other colony members are reproductively suppressed, although this suppression can be reversed following the removal or death of the queen. We examined dominance and queen succession within captive colonies to investigate the relationship between urinary testosterone and cortisol, dominance rank and reproductive status; and to determine if behavioural and/or physiological parameters can be used as predictors of queen succession. Social structure was characterized by a linear dominance hierarchy before and after queen removal. Prior to queen removal, dominance rank was negatively correlated with body weight and urinary testosterone and cortisol titres in males and females. Queen removal results in social instability and aggression between high ranking individuals. Dominance rank appears to be a good predictor of reproductive status: queens are the highest ranking colony females and are succeeded by the next highest ranking females. The intense dominance-related aggression that accompanies reproductive succession in naked mole-rats provides empirical support for optimal skew theory.

Animals↗

PubMed2002

Influence of storage days on the distribution for time of embryonic mortality during incubation.

Breakout analysis of 11,254 chicken eggs that failed to hatch was used to assess the influence of storage days on the distribution for time of embryonic mortality during incubation and on reproductive efficiency. Eggs were collected over 30 d, stored from 2 through 18 d, and incubated in two hatches. For each storage day within hatch, proportions of embryonic mortality during each of the 21 d of incubation, among embryos that did not survive incubation, were fitted by a diphasic Weibull distribution. Multivariate analysis was used to assess the influence of hatch and storage days within hatch on parameters of the distribution and on two measures of reproductive efficiency, proportions of embryonic mortality during incubation among all eggs incubated P(mort) and among fertile eggs incubated P(mort/fert), and to obtain partial correlation coefficients. Storage days influenced the distribution for time of embryonic mortality in each hatch, but the effect was different for each hatch. As the number of storage days increased, P(mort) and P(mort/fert) increased. Partial correlations showed that P(mort) and P(mort/fert) decreased as the proportion of embryos that died during the first phase decreased and as duration of the second phase increased. The shape of the distribution for time of mortality during incubation influenced reproductive efficiency. Factors that influence the shape of this distribution, other than hatch and storage days within hatch, should be studied to increase reproductive efficiency in the poultry industry.

Animals↗

PubMed1989

[Retinoic acid modification of cell culture used for reproduction of enteropathogenic viruses].

The 0.001-0.005% retinoic acid injection into the growth cultural medium of prime and continue cell cultures 12-24h before inoculation considerably raised the cell sensitivity to animal entero- and coronaviruses. The entero- and coronaviruses concentrations in cultural medium increased by 10(1.58) and 10(1.68)TCID 50/1.0 respectively. The optimized parameters of the cell culture processing for the enteropathogenic viruses reproduction improvement are proposed.

Animals↗

PubMed2001

Rovibrational and Rotational Spectroscopy of Levels of Propyne around 1000 cm(-1).

Four vibrational levels in the energy region around 1000 cm(-1) were studied. These were the v(5)=1 and v(8)=1 fundamental levels, both components of the v(9)=v(10)=1 combination level (l(9)=l(10)=+/-1 and l(9)=-l(10)=+/-1), and both components of the v(10)=3 overtone level (l(10)=+/-1 and +/-3). New FTIR spectra with a synchrotron radiation source were recorded in the region of the "superhot" v(10)=3<--2 bands, which made possible the first assignment of levels of the v(10)=3(+/-1) sublevel. More than 330 new rotational transitions in the combination and overtone levels were measured by millimeter-wave spectroscopy betwen 50 and 360 GHz. The new data were analyzed simultaneously together with the previously assigned rovibrational data for the fundamental and combination levels and rotational data for the fundamental levels using a global model with all anharmonic, Coriolis, l-type, and alpha-resonances. Significant improvement of data reproduction and very good consistency with the Hamiltonian parameters of the lower vibrational levels v(9)=1 and v(10)=1, 2 were achieved. A strong dependence of the A(v) constant on the l(10) quantum number is found for propyne: this is shown to be characteristic of skeleton C-C identical withC or C-C identical withN bending modes in H(3)CCCH, H(3)CCN, and their fully deuterated species. Copyright 2001 Academic Press.

Journal Article↗

PubMedDate not supplied

Use of the Retinoid Pregnancy Prevention Program in Canada: patterns of contraception use in women treated with isotretinoin and etretinate.

We sought to describe demographic characteristics of and pattern of contraception use by Canadian women prescribed synthetic retinoids who voluntarily contacted the Motherisk Program in Toronto and to describe the degree of use of the Pregnancy Prevention Program (PPP) for retinoids. Prospectively gathered intake data from isotretinoin-exposed women was statistically compared to that from matched controls selected from our database. Intake data is qualitatively reported for etretinate-exposed women. We included women who voluntarily contacted the Motherisk Program from November 1, 1988, to January 30, 1991, for counseling about reproductive risks of isotretinoin or etretinate. Primary outcome parameters were maternal age, race, marital status, socioeconomic status; gravity, parity, previous miscarriages and elective abortions, maternal tobacco and ethanol exposure, contraception use, and use of PPP (educational components used, patient recollection of warnings). The 26 isotretinoin-exposed women were younger than controls (25.2 [SD 6.7] years vs 28.9 [SD 5.1] years, P = 0.03), tended to be adolescent (30.8% vs. 3.8%, P = 0.014) and sought counselling later in gestation (10.1 [SD 8] weeks vs. 6 [SD 4.2] weeks, P = 0.01). Twenty (77%) knew the drug was teratogenic, yet 10 (38.5%) used no contraception, 6 (23.1%) experienced method failure, and 2 (8%) stopped contraception during isotretinoin therapy. In conclusion, although cognizant of the teratogenicity of isotretinoin, more than one-third of the women in this study used no birth control or experienced contraception failure. In this same group, however, compliance with contraception use appeared to increase in those who saw more of the PPP.

Adult↗

PubMed2005

Ecological impact assessment of metallurgic effluents using in situ biomarker assays.

An ecological impact study was performed based on in situ biomarker assays with the waterflea Daphnia magna. The effects of metallurgic effluents on the energy metabolism, anti-oxidative metabolism and DNA damage were assessed in caged daphnids during a 4-week study. In situ survival and reproduction studies demonstrated a clear impact on these parameters in organisms exposed in the most polluted areas. At the downstream--sublethal--zone the organisms were disturbed within their tolerance limits, resulting in alterations of their energy metabolism. These data suggest an acclimation hypothesis, which was tested through the analysis of the energy metabolism of resident species: isopods and amphipods. These organisms had shifted to a decrease in their overall energy metabolism compared to the upstream region. This change in some biochemical processes suggests a selective advantage to cope with the prevailing environmental conditions. In addition, we found clear genotoxic effects caused by the industrial discharges that might correlate with a reduction in (long-term) survival.

Adaptation, Physiological↗

PubMed2004

Immunotoxicological consequences of perinatal chemical exposures.

The developing immune system may be especially vulnerable to the toxic effects of immunotoxicants. A number of chemicals has been identified that affect the developing immune system. Yet, so far there are no immune parameters included in current guidelines for developmental or reproductive toxicity testing. It is recommended that such guidelines are updated so that also the developing immune system is evaluated as a potential target of toxicity during developmental stages.

Animals↗

PubMed2000

The transmission dynamics of the aetiological agent of scrapie in a sheep flock.

We formulate and investigate the properties of a model framework to mimic the transmission dynamics of the aetiological agent of scrapie in a sheep flock. We derive expressions for summary parameters that characterize transmission scenarios, notably the basic reproduction number R(0) and the mean generation time T(g). The timescale of epidemic outbreaks is expressed in terms of R(0) and cumulants of the generation time distribution. We discuss the relative contributions to the overall rate of transmission of horizontal and vertical routes during invasion and in endemicity. Simplified models are used to obtain analytical insight into the characteristics of the endemic state.

Animals↗

PubMed2002

Beneficial influences of systemic cooperation and sociological behavior on longevity.

During his long research career in the field of aging, Dr Bernard Strehler developed a series of theories concerning the identity of genes that can promote longevity and their role in natural selection. As a tribute to Dr Strehler, we have taken this opportunity to summarize a selection of these theories and to illustrate how these insights have influenced our search for longevity genes within the immune system. The identification of longevity genes has proven difficult. We believe that, at least in part, this reflects the emphasis on the concept of survival of the 'physically' fittest. We have used the immune system as a model to demonstrate that, over and above the self-evident advantage of those genes that contribute the attributes commonly associated with survival of the 'physically' fittest, those genes that lead to a predisposition to cooperate also confer a competitive survival advantage. As the acquisition of cooperativity in a society is linked to support mechanisms provided by older individuals, the search for longevity genes should not be limited to those genes that are associated with extended expression of a youthful phenotype. Rather these studies should be expanded to include identification of those genes that regulate physiologic parameters that affect individual longevity, even if they do not correspond with the traditional view of reproductive competitiveness. At the societal level, longevity genes may encode attributes that regulate sociologic or psychological parameters that may contribute to a tendency to non-aggressive or cooperative behavior that leads to achievement of common goals necessary for the survival of the species. This view of the selection for longevity impacts the analysis of longevity genes and aging at the organismal level. Dr Strehler viewed organismal aging as an integrated functional state, in which he conceived the outcome as reflecting the net balance of functional decrementers and evolved compensatory features. We propose that, in more evolved species, the longevity genes will be those genes, or sets of genes, that counterbalance of age-related functional decrementers with the age-related manifestation of evolved compensatory features. Thus, as illustrated here through analysis of the immune system, the longevity genes may well be those genes that promote overall systemic cooperation and compensation within the immune system and associated systems, rather than the genes that prevent age-related alterations in only one or a limited number of pathways.

Aging↗

PubMed2002

Safety aspects of gonadotrophin-releasing hormone antagonists in ovarian stimulation procedures: ovarian hyperstimulation syndrome and health of children born.

The safety of ovarian stimulation procedures or the procedure of assisted reproduction in general can be estimated by various parameters. Two of the most important are the health of children born after the procedure and the incidence of ovarian hyperstimulation syndrome (OHSS). The latter is important because it is the most severe, potentially life-threatening complication of any stimulation procedure. The use of gonadotrophin-releasing hormone (GnRH) antagonists in ovarian stimulation protocols has had no impact on the health of children born. This was proven in 227 children born after the use of cetrorelix and in 73 children born after the use of ganirelix. To analyse the incidence of OHSS and the impact of GnRH antagonists on clinical pregnancy rates compared with the long protocol, a meta-analysis was done. This showed a reduction of OHSS with the use of cetrorelix. Furthermore, when compared with the long protocol, clinical and ongoing pregnancy rates were not significantly reduced with the use of cetrorelix. Taken together, the use of GnRH antagonists are safe with regard to children's health. The incidence of OHSS does not increase with ganirelix, and a reduction can be expected with cetrorelix.

Female↗

PubMed1992

Estimation of the dynamics and rate of transmission of classical swine fever (hog cholera) in wild pigs.

Infectious diseases establish in a population of wildlife hosts when the number of secondary infections is greater than or equal to one. To estimate whether establishment will occur requires extensive experience or a mathematical model of disease dynamics and estimates of the parameters of the disease model. The latter approach is explored here. Methods for estimating key model parameters, the transmission coefficient (beta) and the basic reproductive rate (RDRS), are described using classical swine fever (hog cholera) in wild pigs as an example. The tentative results indicate that an acute infection of classical swine fever will establish in a small population of wild pigs. Data required for estimation of disease transmission rates are reviewed and sources of bias and alternative methods discussed. A comprehensive evaluation of the biases and efficiencies of the methods is needed.

Animals↗

PubMed2005

Dynamically modeling SARS and other newly emerging respiratory illnesses: past, present, and future.

The emergence and rapid global spread of the severe acute respiratory syndrome (SARS) coronavirus in 2002-2003 prompted efforts by modelers to characterize SARS epidemiology and inform control policies. We overview and discuss models for emerging infectious diseases (EIDs), provide a critical survey of SARS modeling literature, and discuss promising future directions for research. We reconcile discrepancies between published estimates of the basic reproductive number R0 for SARS (a crucial epidemiologic parameter), discuss insights regarding SARS control measures that have emerged uniquely from a modeling approach, and argue that high priorities for future modeling of SARS and similar respiratory EIDs should include informing quarantine policy and better understanding the impact of population heterogeneity on transmission patterns.

Communicable Diseases, Emerging↗

PubMed2002

Time-delayed spread of viruses in growing plaques.

The spread of viruses in growing plaques predicted by classical models is greater than that measured experimentally. There is a widespread belief that this discrepancy is due to biological factors. Here we show that the observed speeds can be satisfactorily predicted by a purely physical model that takes into account the delay time due to virus reproduction inside infected cells. No free or adjustable parameters are used.

Bacteriophage T7↗

PubMed1992

Time perception: effects of sex and sound intensity on scales of subjective duration.

Six women and six men reproduced ten time intervals varying in logarithmic steps between 1.3 and 20 s. The durations were indicated by white noise of 10, 25, 40 and 55 dB SL, different sound intensities in different sessions. It was found that (i) greater sound intensity entails shorter reproductions, and (ii) reproductions by male observers are shorter than those by female, although for both (i) and (ii) there is an interaction with the standard durations. The data were treated in accordance with the "parallel-clock model" (Eisler, 1975), whereby the parameters of the psychophysical power function are determined from duration reproduction data. As in previous experiments (Eisler, 1975), the data showed a break in the function entailing two segments. The effect of sound intensity could be attributed to the exponent, which was lower for stronger noise, and the effect of sex to the weight coefficient of the upper relative to the lower segment of the psychophysical function, the coefficient being lower for men.

Adult↗

PubMed1997

Determination of IL-1 and IL-6 levels in human embryo culture-conditioned media.

PROBLEM: The aim of this study was to evaluate the presence of interleukin-1 (IL-1) and IL-6 in 24-hour human embryo culture-conditioned media (HECCM) and to find any embryo-related factor(s) to predict pregnancy during IVF procedure. METHOD: IL-1 beta and IL-6 levels were measured in 36 samples of HECCM and 17 cell culture medial that had not been exposed to embryos, which were used as controls. Both cytokine levels were measured by the ELISA technique, using commercially available kits. RESULTS AND CONCLUSIONS: We found an average IL-1 beta level +/- SEM of 82 +/- 4 pg/ml (n = 11) in HECCM from viable pregnancies and a significantly lower value, 14 +/- 2 pg/ ml (n = 25, P < 0.001), in HECCM from embryos that did not lead to viable pregnancies. In control medial the average IL-1 beta level was 11 +/- 1 pg/ml (n = 17), (P < 0.001 vs. HECCM from viable pregnancies). In contrast IL-6 levels were undetectable in all samples analyzed. Judging by our results we suggest that measurement of IL-1 level in HECCM could be a useful parameter for predicting implantation in techniques of assisted reproduction.

Adult↗

PubMedDate not supplied

An automated dosimetry data-acquisition and analysis system at the LAMPF pion therapy facility.

An automated data-acquisition and analysis system has been developed for dosimetry measurements on the pion therapy beam at the Clinton P. Anderson Meson Physics Facility Biomedical Channel in Los Alamos using a PDP-11/45 computer and CAMAC interface. Initialization, test, and monitor programs allow the user to set the physical limits of scanner travel, test the data lines, calibrate the analog signals for the scanner position, and monitor the analog versus digital values of the scanner position during operation. Data-acquisition programs scan beams in one, two, and three dimensions. Many options are available to the user in selecting the scan parameters and in changing some of these parameters during scanning. Data-analysis programs provide reproduction of stored data, comparison of linear scans, beam profiles along any line of a planar or volume scan, and isodose distributions from any planar scan or from any planar scan or from any plane of a volume scan. Other programs summarize stored data files and search for specific data according to the user's instruments.

Computers↗