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PubMed1998

Methods to obtain quantitative parametric descriptions of the optical surfaces of the human crystalline lens from Scheimpflug slit-lamp images. I. Image processing methods.

Of the methods developed (e.g., phakometry, magnetic resonance imaging, etc.) for noninvasive measurement of the geometry of the anterior segment of the human eye, Scheimpflug photography offers the best resolution and the highest precision. The primary obstacle encountered with this or any other image-based method has been in obtaining quantitative measurements directly from the images. Image enhancement (gray-scale gradient analysis) and pattern recognition methods (Hough transform and recursive least-squares algorithms) are developed so that parametric representations of lens surfaces and zone boundaries can be obtained directly from the images. Methods to correct for nonlinear Scheimpflug camera reproduction ratios and provide error estimates for geometrical parameters are also developed and will be presented separately. Combined, these techniques yield representations of lens geometry having sufficient precision, to which paraxial ray tracing can be applied to determine lens optical properties by using well-posed optical models with one unknown.

Algorithms↗

PubMed2005

Plasma and urine levels of electrolytes, urea and steroid hormones involved in osmoregulation of cetaceans.

Cetaceans are well adapted to their hyperosmotic environment by properly developed osmoregulatory ability. A question here is how they regulate water and mineral balances in marine habitats. In the present study, we determined blood and urine levels of various chemicals involved in osmoregulation, compared them with those in artiodactyls, and characterized the values in the whales. Blood and urine samples obtained from baleen whales of common minke (Balaenoptera acutorostrata), sei (B. borealis), and Bryde's whales (B. brydei), and toothed whales of sperm whales (Physeter macrocephalus) were analyzed for osmolality, major electrolytes, urea, steroid hormones and glucose. The urine osmolality and Na(+) concentrations in the cetaceans were much higher than those in the cattle. Furthermore, the cetaceans had 5 to 11-fold urea in plasma than the cattle, and 2 to 4-fold urea in urine. There were no significant difference in the plasma concentrations of corticosteroids between the cetaceans and the cattle. The present results indicate that the osmoregulatory parameters seem to be not affected by the reproductive stage and sex steroid hormones. The concentrations of urea in plasma and urine of the baleen whales were higher than those of the sperm whales, indicating a possibility that their osmoregulatory mechanisms may be correlated to their feeding habits. The present results suggest that cetaceans have unique osmoregulatory mechanisms by which they excrete strongly hypertonic urine to maintain fluid homeostasis in marine habitats.

Analysis of Variance↗

PubMed1985

Prevalence, worm burden and other epidemiological parameters of Ascaris lumbricoides infection in rural communities in Korea.

The epidemiological status of ascariasis was analyzed in 8 rural villages in Korea, through observation of its epidemiological parameters such as prevalence, worm burden and basic reproductive rate. Total 978 inhabitants were subjected to stool examination and recovery of worms after chemotherapy with pyrantel pamoate. The results were as follows: The worm positive rate in each village was 16.5~79.5%, while the egg positive rate was 9~18% lower, 3.3~66.7%. The average worm burden(among all inhabitants) ranged from 0.21 to 8.44 by villages and the frequency of cases with each worm burden showed negative binomial distributions with 'k' values of 0.38-0.54. The prevalence rates (worm) in each village was almost identical with the theoretical ones from Anderson and May's equation; p=1-(1+M(*)/k)**(-k), where 'p' is worm prevalence and 'M(*)' equilibrium average worm burden. The basic reproductive rate 'R' was calculated from 1.03 to 2.11. It is suggested that, although 'R' in lower endemic areas is approaching to the breakpoint of reinfection (R=1), control programs of ascariasis in Korea should be continued until it becomes below the level nationwidely.

Journal Article↗

PubMed2000

Physiological responses associated with sustained delivery of T, DHT, and AED in male rats.

The factors responsible for the marked gender difference in the risk of coronary heart disease and remain controversial. Several clinicians and basic scientists support the hypothesis that a protective effect of endogenous estrogen is the key, however epidemiological data failed to prove this trend. The role of endogenous androgens or sex steroid hormones on the development of atherosclerosis has received little attention over the years. The specific objectives of this study are: 1) to deliver testosterone (T), dihydrotestosterone (DHT), or androstenedione (AED) at sustained levels by tricalcium phosphate lysine (TCPL) ceramic delivery devices, and 2) to quantify major biochemical markers levels such as lactate dehydrogenase activity (LDH), total cholesterol, thiobarbituric reactive species associated with sustained delivery of androgens and 3) to evaluate the histopathological changes in vital and reproductive organs associated with excess androgens delivery in adult intact male rats. A total of sixteen male rats were randomly divided into four equal groups. Rats in group I served as intact controls, and animals in groups II-IV were implanted with a single TCPL delivery device contained T (40 mg), DHT (40 mg), or AED (40 mg), respectively. Animals in all groups were weighed and blood was drawn biweekly for cholesterol, LDH and TBAR analysis. At the end of ninety days post implantation, the animals were sacrificed and the organs removed, processed embedded, sectioned and screened for morphological changes. The results of this study suggest that: 1) sustained deliver of androgens caused a statistically significant increase (p < 0.05) in the prostate and the seminal vesicle weights, while the epididymis weights remained similar to control intact animals, 2) decreases in adrenal gland weight was detected in animals treated with androgens compared to control animals, 3) kidney weights increased in all androgen groups compared to control, 4) no differences were observed in heart, spleen, or body weights between the groups, 5) TBAR analysis, as well as LDH activity were not different between androgen treated animals and control animals, and 6) total cholesterol was significantly reduced in T and DHT treated groups compared with control and AED treated animals. The decrease in total cholesterol and reduction in adrenal gland weight may suggest impairment of cholesterol synthesis. In conclusion, this study provides information on the effects of sustained release of DHT, T and AED on the reproductive organs, vital organs, as well as physiological parameters such as TBARS (cellular damage) and total cholesterol.

Androstenedione↗

PubMedDate not supplied

Puberty is delayed in male growth hormone receptor gene-disrupted mice.

The role of insulin-like growth factor-I (IGF-I) in the initiation of puberty and testicular function is poorly understood. Growth hormone (GH) receptor (R) gene-disrupted mice or GHR gene "knockouts" (GHR-KO) are GH resistant and IGF-I deficient. To assess whether the age of sexual maturation is affected by the absence of IGF-I, various parameters of sexual development including testicular and accessory reproductive organ weights, balanopreputial separation, germ cell development, and intratesticular testosterone levels were determined in normal and GHR-KO mice between the ages of 25 and 60 days. In addition, at 36 days of age, the testosterone response to luteinizing hormone (LH) treatment was assessed in these mice. The results indicate that the balanopreputial separation was delayed 5 days, and a significant increase in the weights of the seminal vesicles (SV) occurred later in GHR-KO mice than in normal animals (between 30 and 35 days and between 35 and 40 days, respectively). Also, the weights of testes and epididymii were significantly reduced in GHR-KO mice. The intratesticular testosterone levels and the testosterone response to LH treatment were attenuated in GHR gene-disrupted mice. Furthermore, elongated spermatids appeared later in the testes of GHR-KO mice than in the testes of normal mice. These results suggest that the absence of IGF-I secretion delays the normal course of sexual maturation in male GHR-KO mice, indicating that IGF-I plays an important role in the initiation of puberty in male mice.

Animals↗

PubMed2002

Methods for predicting sexual maturity in male cynomolgus macaques on the basis of age, body weight, and histologic evaluation of the testes.

In pharmaceutical drug safety testing, sexual maturity is an important experimental parameter. Histologic immaturity of the tissues of the reproductive system can interfere with the interpretation of compound-related effects on the reproductive organs. In female cynomolgus macaques, determination of sexual maturity is simplified by the presence of a menstrual cycle. For male cynomolgus macaques, predicting maturity is much more difficult. In this study, we evaluated methods that would reliably predict sexual maturity in male cynomolgus macaques. The results of histologic examination of testes of control male cynomolgus macaques used for drug safety studies were examined retrospectively for evidence of sexual maturity. These data were compared with age and body weight determinations to establish statistical models for determining the probability that a male cynomolgus macaque is sexually mature. This model presents a simple prospective method of predicting sexual maturity in male cynomolgus macaques.

Aging↗

PubMedDate not supplied

Apoptosis in human ejaculated spermatozoa.

After the introduction of assays determining apoptosis in human ejaculated spermatozoa, several studies have been published about the relationship between apoptosis in spermatozoa and semen quality. Apoptosis in spermatozoa is significantly correlated with conventional semen quality parameters, but also with the outcome of assisted reproductive techniques. The apoptotic process is probably set in motion before ejaculation. Determining apoptosis in spermatozoa can improve selection criteria in assisted reproduction.

Annexin A5↗

PubMed2005

The effect of self-fertilization, inbreeding depression, and population size on autopolyploid establishment.

The minority cytotype exclusion principle describes how random mating between diploid and autotetraploid cytotypes hinders establishment of the rare cytotype. We present deterministic and stochastic models to ascertain how selfing, inbreeding depression, unreduced gamete production, and finite population size affect minority cytotype exclusion and the establishment of autotetraploids. Results demonstrate that higher selfing rates and lower inbreeding depression in autotetraploids facilitate establishment of autotetraploid populations. Stochastic effects due to finite population size increase the probability of polyploid establishment and decrease the mean time to tetraploid fixation. Our results extend the minority cytotype exclusion principle to include important features of plant reproduction and demonstrate that variation in mating system parameters significantly influences the conditions necessary for polyploid establishment.

Computer Simulation↗

PubMed1994

The role of DNA damage and inhibition of poly(ADP-ribosyl)ation in loss of clonogenicity of murine L929 fibroblasts, caused by photodynamically induced oxidative stress.

Reactive oxygen species are used to eradicate malignant cells in photodynamic therapy as well as in other cancer therapies. Despite many efforts, the pathways leading to cellular damage and cell killing due to the action of these species are poorly understood. In previous studies with hematoporphyrin derivative-sensitized L929 murine fibroblasts, the only parameter for which a relation with photodynamically induced reproductive cell death could not be excluded was inhibition of DNA excision repair. The present results show that loss of clonogenicity of these cells in fact is related to a series of effects, including the development of slight, irreperable DNA damage, a virtually complete inhibition of poly(ADP-ribosyl)ation activation, a transient elevation of the intracellular calcium concentration and, after a lag time of about 8 h, DNA fragmentation caused by endonuclease activity. This conclusion is supported by the observation that photodynamic treatment inhibited the repair of X-ray-induced DNA strand breaks and suppressed X-ray- and methyl methanesulfonate-induced enhancement of poly(ADP-ribosyl)ation. Our experimental results further suggest that in this cell line the photodynamically induced inhibition of enhanced poly(ADP-ribosyl)ation could well be involved in inhibition of repair of DNA strand breaks and in activation of endonuclease activity.

Animals↗

PubMed1997

Fertility parameters in male Irish wolfhounds: a two-year follow-up study.

The reproductive performance of 25 male Irish wolfhounds was examined in a two-year follow-up study. Results of a previous study showed that 37 Irish wolfhounds had lower libidos, smaller testicles and poorer semen quality than 67 control dogs examined. This study was undertaken to determine whether fertility parameters had changed after a further two years. Forty-four dogs of 21 breeds were used as controls. No change in libido was observed in either group after two years; the Irish wolfhounds still exhibited lower libidos than the control dogs. In both studies, the Irish wolfhounds showed a softening of testicular tissue with a significantly higher incidence than control dogs. This difference became more marked after two years. Semen quality had declined in Irish wolfhounds and the differences between the two groups became more accentuated. Inbreeding coefficients for the Irish wolfhounds were low, suggesting that this was a factor contributing to the poor reproductive function. However, several Irish wolfhounds had been ill during the follow-up period which, together with the decline in reproductive efficiency, may reflect a change due to ageing.

Aging↗

PubMed1996

Quantitative investigation of population persistence and recurrent outbreaks of bovine respiratory syncytial virus on dairy farms.

OBJECTIVE: To determine if transmission of virus among seropositive cattle is a plausible mechanism for the permanent presence of bovine respiratory syncytial virus (BRSV) in dairy herds, and how likely, with the scenario for persistence, there will be only 1 clinical outbreak of BRSV per year. DESIGN: Build a stochastic model, parameter estimation from serologic data on BRSV, and interpret the estimated parameter values from the model analysis. SAMPLE POPULATION: Monthly data on the prevalence of antibodies directed against BRSV in sera from all cattle in 6 dairy herds. PROCEDURE: Parameter estimation applying general linear models, model analysis using calculation of the reproduction ratio for simplified models, and Monte-Carlo simulation for the whole model. RESULTS: Persistence of BRSV by transmission among seropositive cattle given estimated parameter values would be accompanied by frequent extinctions (once every 10 to 50 years) and long infectious periods in seropositive cattle (100 days). Moreover, in the model, a single clinical outbreak among seronegative cattle only occurred with external forcing. CONCLUSIONS: From these data, transmission among seropositive cattle is not a plausible mechanism for persistence of BRSV in dairy herds.

Animals↗

PubMed2005

Dietary soy protein and isoflavones: no effect on the reproductive tract and minimal positive effect on bone resorption in the intact female Fischer 344 rat.

Our previous study evaluating 3 months of feeding soy protein or isoflavones (IF) to intact adult Sprague-Dawley (SD) rats showed no change in bone and the vagina but occasional extensive squamous metaplasia of the uterine glandular epithelium was observed. The current study was designed to characterize further these effects of soy protein or IF on the uterus using the Fischer 344 (F344) rat, a known high responder strain to estrogenic stimuli. Three-month-old intact F344 rats were divided into five groups and fed diets containing either casein, low or high amount of soy protein or casein with low or high amount of IF extract. Body weight, urinary deoxypyridinoline (Dpyr), bone mineral density (BMD) of the femur and lumbar, uterine wet weight and histology of the reproductive tract were evaluated. No significant difference was seen in bone parameters between control and treatment groups except for a lower Dpyr in the high soy and a higher lumbar BMD in the low soy groups. No alteration was seen in the reproductive tract of all treatment groups. Contrary to our hypothesis, the present results suggest that the uterus of the F344 strain is less sensitive to dietary soy protein and IF than that of the SD strain.

Animals↗

PubMed1998

Hormonal and gestational parameters in female rats submitted to the pilocarpine model of epilepsy.

Endocrine and reproductive alterations are frequently reported to occur in women with temporal lobe epilepsy as well as in female rats in different experimental models of limbic seizures. As previously reported, women with epilepsy have lower fertility rates than women without epilepsy (Tanganelli, P., Regesta, G., 1992. Neurology (suppl.) 42 (5), 89-93; Cummings, L.N., Guidice, L., Morrel, M.J., 1995. Epilepsia 36, 355-359). In order to investigate the possible substrate of endocrine alterations in epilepsy, hormonal and gestational parameters were studied in female rats submitted to the pilocarpine model of epilepsy. The results demonstrated that the oestrus cycle is altered following pilocarpine-induced status epilepticus and such alteration lasted for several weeks. Progesterone, LH and FSH levels decreased and estradiol levels increased significantly during the period of spontaneous and recurrent seizures. The frequency of seizures during pregnancy and lactation decreased. These results document that significant changes in gonadal, hypophyseal and hypothalamic hormones, as well as in sexual behaviour, occur following status epilepticus induced by pilocarpine administration.

Animals↗

PubMed1998

Alteration of thyroid blood flow during the normal menstrual cycle in healthy Chinese women.

The purpose of this study was to investigate the relationship between thyroid activity and the menstrual cycle by measuring the Doppler parameters of the superior thyroid arteries in women of reproductive age. The study was performed in 27 healthy Chinese women aged between 19 and 28 y for one menstrual cycle, and 25 age-matched healthy Chinese men for 3 weeks for comparison. In women, the peak systolic velocity increased from the follicular phase to the luteal phase, and the pulsatility index decreased from the follicular phase to the ovulatory phase and increased slightly in the luteal phase. In men, alterations in the pattern of thyroid blood flow were not observed; however, the average values of Doppler parameters during the study period in women were similar to those in men. The gender difference in the pattern of flow characteristics in the superior thyroid artery suggests effects of estrogen on thyroid function.

Adolescent↗

PubMed1986

Assessment of reproductive risks.

In the regulatory process, the hazards posed by potentially toxic agents to the female and male reproductive systems and to developing young are evaluated by risk assessment procedures. In this paper, toxicity testing and the regulatory process are discussed, with emphasis on risk assessment. The suggested testing protocols of the Pesticide Assessment Guidelines (U.S. EPA) are presented as an example of testing that might be done to produce toxicity data for an agent. Protocols and end points that are utilized in testing for reproductive effects are described. Included are acute, subchronic, chronic, and short-term tests. The four components of reproductive risk assessment (hazard identification, dose-response assessment, exposure assessment, and risk characterization) are examined. Effects of dibromochloropropane on rabbit testicular parameters are used to demonstrate approaches that could be taken in doing a reproductive risk assessment. Research needs for screening methods, adequate dose-response testing, toxicokinetics, end point development, and extrapolation methods are identified. Finally, this paper discusses selected areas in which changes in reproductive risk assessment are anticipated, as well as the mechanism for influencing the nature and extent of those changes.

Abortion, Spontaneous↗

PubMed1996

Semen parameters and sperm morphology in men in unexplained recurrent spontaneous abortion, before and during a 3 year follow-up period.

To investigate the role of the 'male factor' in the pathogenesis of recurrent spontaneous abortion (RSA), especially sperm morphology abnormalities, 120 previously selected couples with unexplained RSA were studied for sperm parameters retrospectively and prospectively. The patients were subdivided into three subgroups, depending on their reproductive outcome during the 3 years of follow-up study: (i) 48 RSA couples who achieved a successful pregnancy; (ii) 39 RSA couples who experienced further abortions, and (iii) 33 RSA couples who experienced infertility during the follow-up period. A semen analysis was performed twice at the time of inclusion in this study, and twice again during the 3 year follow-up period. No significant differences in semen parameters were observed between RSA males and fertile controls. Instead, significant differences were observed between the group of RSA couples who experienced infertility during the follow-up and the other two groups (RSA couples who achieved successful pregnancy and RSA couples who experienced miscarriages and no live birth during the follow-up) for sperm concentration (P < 0.01 and P < 0.01 respectively), sperm motility (P < 0.01 and P < 0.01 respectively) and sperm morphology abnormalities (P < 0.01 and P < 0.01 respectively). Sperm morphology abnormalities do not seem to be involved in determining RSA; instead, they are an aetiological factor in determining infertility in patients, along with the other semen parameters, in the RSA couple's subsequent reproductive life. Semen analysis is an important test in the clinical management of RSA couples.

Abortion, Habitual↗

PubMedDate not supplied

Subjective time scaling: influence of age, gender, and Type A and Type B behavior.

Forty-eight subjects, divided into 4 equal groups (young and older female, young and older male), reproduced 19 time intervals varying in logarithmic steps between 1.3 and 20 s. The durations were indicated by noise of 50 dB SL. To assess Type A and Type B behavior, the subjects were administered a Swedish version of Jenkins Activity Survey with 21 items. It was found that 1. reproductions of durations by older subjects are longer than those by younger subjects, and 2. reproductions by male subjects are shorter than those by female, although an interaction was also detected between gender and the standard durations. Type A and Type B behavior did not show any main effect. The data were treated in accordance with the "parallel-clock model", whereby the parameters of the psychophysical power function are determined from duration reproduction data. As in previous experiments, the data showed a break in the function, entailing two segments. The effect of both age and gender could be explained by the weight coefficient of the upper relative to the lower segment of the psychophysical function, the coefficient being lower for male and higher for older subjects.

Acoustic Stimulation↗

PubMed1985

Partial reversal of ethanol-induced male reproductive pathology following abstinence.

To date, no longitudinal studies have been carried out to determine the recovery of ethanol-related reproductive failure subsequent to moderate periods of abstinence. An animal model (C57B1 mouse) was utilized to examine the effectiveness of abstinence for reversal of ethanol-induced reproductive failure. After treatment with either a 5% (v/v) ethanol diet (10 weeks) or a 6% (v/v) ethanol diet (5 weeks), ethanol-treated animals and their pair-fed controls were electroejaculated and hemicastrated (right testis and accessory organs); their reproductive tracts and epididymal spermatozoa were examined. Ingestion of the 5% and 6% ethanol diets resulted in significantly (P less than 0.05) decreased weights of testes (24% and 28%, respectively) and seminal vesicles/prostate (20%, 6% diet only), increased frequencies of germ cell desquamation (480% and 400%), inactive seminiferous tubules (186% and 567%), sperm dysmorphology (31% and 119%) and inhibition of in vitro fertilization of mouse oocytes by epididymal spermatozoa (26% and 62%), as compared to their respective pair-fed control values. Also observed were significant decreases in epididymal sperm content (72%, 6% diet only), total motile spermatozoa (85%, 6% diet only) and seminal vesicles epithelial cell height (13% and 29%). No abnormal semen parameters were observed after treatment with the 5% ethanol diet; however, in animals treated with the 6% diet, significant decreases were noted in coagulum weight (50%), sperm count (85%) and acid phosphatase content (53%). Improvement in all parameters was observed in the contralateral half of the reproductive tract subsequent to 10 weeks abstinence. Only germ cell desquamation remained significantly elevated (100% as compared to control) in animals that ingested the 5% diet. In contrast, significant abnormalities persisting 10 weeks after treatment with the 6% ethanol diet included increased germ cell desquamation (200%), inactive seminiferous tubules (157%) and sperm dysmorphology (39%) and decreased forward progression (17%) of epididymal sperm, as compared to values. These findings are discussed in relation to the influence of alcohol consumption on male reproductive function in man.

Animals↗