bluuebunny/crossref_metadata_2025 huggingface dataset:
Brain-derived neurotrophic factor promotes bovine oocyte cytoplasmic competence for embryo development
Authors: Martins da Silva S J , Gardner J O , Taylor J E , Springbett A , De Sousa P A , Anderson R A
Published: March 2005

The ability of an oocyte to support early embryonic development requires both nuclear and cytoplasmic maturation. We have investigated the effects of brain-derived neurotrophic factor (BDNF) on maturation of the bovine oocyte and embryo development after parthenogenetic activation. By RT-PCR and immunohistochemistry, cumulus and oocytes were shown to express mRNA and protein for BDNF and the p75 common neurotrophin receptor. However, mRNA for the BDNF-specific full length and truncated isoforms of the TrkB receptor are only detected in cumulus, suggesting that oocytes and cumulus differ in their capacity to respond to neurotrophin signalling. Inin vitromaturation experiments, the proportion of cumulus oocyte complexes maturing to metaphase II was not altered by BDNF in groups lacking fetal calf serum (FCS), but was significantly lower than the positive control containing 10% FCS (P< 0.01). However, after maturation, the proportion of parthenogenetically activated oocytes forming blastocysts was highest for 10 ng/ml BDNF (24%,n= 95) followed by 100 ng/ml BDNF (18%,n= 91) and 10% FCS (15%,n= 103), which in turn were greater than no serum (10%,n= 83;P< 0.01). Maturation in the presence of a BDNF blocking antibody resulted in a blastocyst yield that was comparable to the absence of serum, and lower than in the presence of BDNF (P< 0.01). Similar effects on progression to metaphase II and blastocyst formation were observed using oocytes matured without cumulus. Together, these results provide the first evidence for a role for neurotrophins in promoting oocyte cytoplasmic competence to support embryonic development, despite being insufficient in the absence of serum to enhance nuclear maturation.
Effect of steroids and nitric oxide on pituitary hormone release in ovariectomized, peripubertal rats
Authors: Russell Jill M , Murphree E , Janik J , Callahan P
Published: March 2005

The purpose of this study was to determine the effects of the duration of steroid depletion on the steroid-induced luteinizing hormone and prolactin surges in ovariectomized, peripubertal female rats. Additionally, the role of nitric oxide (NO) in mediating the surge responses was determined. Peripubertal, 6-week-old, female Sprague-Dawley rats were ovariectomized. One or three weeks later, animals were injected with 17β-estradiol (50 μg, sc) followed 48 h later by progesterone (2.5 mg, sc). Effects of NO were examined by administeringl-arginine (300 mg/kg, ip). The response of ovariectomized, adult females to steroid treatment was also determined.

One and three weeks after ovariectomy, steroid replacement produced an LH and prolactin surge in peripubertal animals. However, both the magnitude and duration of the LH surge was greater 3 weeks after ovariectomy. Whilel-arginine significantly enhanced the magnitude of the LH surge 1 week after ovariectomy, by 3 weeksl-arginine caused a decrease in the duration, but not the magnitude of the surge. In contrast,l-arginine did not affect either the magnitude or duration of the prolactin surge one week after ovariectomy, but diminished the magnitude after 3 weeks of steroid depletion. In adults, steroids induced significant increases in both LH and prolactin. These results demonstrate that sensitivity to NO stimulation of LH, but not prolactin secretion, is modulated by the duration of gonadal steroid hormone depletion. The differences in the responsiveness of LH and prolactin to steroid-induced stimulation in peripubertal animals demonstrate that these hormones are regulated by NO through different mechanisms.
Heat stress diminishes gonadotropin receptor expression and enhances susceptibility to apoptosis of rat granulosa cells
Authors: Shimizu Takashi , Ohshima Izumi , Ozawa Manabu , Takahashi Satoko , Tajima Atsushi , Shiota Masayuki , Miyazaki Hitoshi , Kanai Yukio
Published: March 2005

Heat stress inhibits ovarian follicular development in mammalian species. We hypothesized that heat stress inhibits the function of follicular granulosa cells and suppresses follicular development. To test this, immature female rats were injected with pregnant mare serum gonadotropin (PMSG) at 48 h after the start of temperature treatment (control: 25 °C, 50% RH; heat stress: 35 °C, 70% Relative Humidity). The ovaries and granulosa cells of follicles at different developmental stages were analyzed for gonadotropin receptor levels and aromatase activity; estradiol levels were measured in follicular fluid. Before injection, heat stress diminished only the amount of FSH receptor on granulosa cells of antral follicles. During PMSG-stimulated follicular development, heat stress strongly inhibited gonadotropin receptor levels and aromatase activity in granulosa cells, and estradiol levels in the follicular fluid of early antral, antral and preovulatory follicles. To examine apoptosis and mRNA levels of bcl-2 and bax in granulosa cells, follicles harvested 48 h after PMSG injection were cultured in serum-free conditions. Heat-stressed granulosa cells showed a time-dependent increase in apoptosis. The bcl-2 mRNA levels were similar in control and heat-stressed granulosa cells; bax mRNA levels were increased in heat-stressed granulosa cells. According to these results, heat stress inhibits expression of gonadotropin receptors in granulosa cells and attenuates estrogenic activity of growing follicles, granulosa cells of heat-stressed follicles are susceptible to apoptosis, and the bcl2/bax system is not associated with heat-stress-induced apoptosis of granulosa cells. Our study suggests that decreased numbers and function of granulosa cells may cause ovarian dysfunction in domestic animals in summer.
Bone morphogenetic protein 15 and growth differentiation factor 9 co-operate to regulate granulosa cell function in ruminants
Authors: McNatty Kenneth P , Juengel Jennifer L , Reader Karen L , Lun Stan , Myllymaa Samu , Lawrence Steve B , Western Andrea , Meerasahib Mohamed F , Mottershead David G , Groome Nigel P , Ritvos Olli , Laitinen Mika P E
Published: March 2005

The oocyte-secreted polypeptide growth factors, growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15, also known as GDF9B) have both been shown to be essential for ovarian follicular development and ovulation rate. In addition, it is known from both in vivo and in vitro studies that these factors co-operate in some manner. To date, most studies examining the in vitro effects of these growth factors have used the rodent model. However, the evidence suggests that these growth factors have somewhat different roles between rodents and ruminants. Therefore, the objectives of these studies were to examine the effects of GDF9 and BMP15, alone and together, on the functions of ovine and bovine granulosa cells under in vitro conditions. Ovine (o)BMP15 given together with murine (m)GDF9 or oGDF9 was more potent in stimulating 3H-thymidine incorporation by ovine granulosa cells compared with each growth factor alone. For bovine granulosa cells, there appeared to be little or no co-operativity between oBMP15 and oGDF9 as oBMP15 alone was as potent as any combination of the two growth factors in stimulating 3H-thymidine uptake. The species of origin of GDF9 affected the progesterone response in ovine granulosa cells with mGDF9 stimulating and oGDF9 inhibiting progesterone production. Ovine BMP15 alone had no effect on progesterone production by ovine granulosa cells and these growth factors did not appear to co-operate. FSH-stimulated progesterone production by bovine granulosa cells was most potently inhibited when oBMP15 and murine or ovine GDF9 were administered together. As was observed for progesterone, the species of origin of GDF9 affected inhibin production by ovine granulosa cells where mGDF9 inhibited while oGDF9 stimulated production. Murine GDF9 also inhibited inhibin production from bovine granulosa cells. For both ovine and bovine granulosa cells, BMP15 alone had no effect on inhibin production and there did not appear to be any co-operation between GDF9 and BMP15. These results indicate that the effects of BMP15 and GDF9 varied with respect to the species of origin of the growth factor. Moreover, the effects of GDF9 and BMP15 together were often co-operative and not always the same as those observed for these growth factors alone.
Impact of a mild scrotal heat stress on DNA integrity in murine spermatozoa
Authors: Banks Stephen , King Sasha A , Irvine D Stewart , Saunders Philippa T K
Published: March 2005

An increase in scrotal temperature can lead to the production of poor quality spermatozoa and infertility. In the present study we have used mice to examine the impact of mild, scrotal heat stress (42 °C for 30 min) on numbers of spermatozoa as well as on the integrity of their DNA. Spermatozoa recovered from the epididymides hours (1 to 24) or days (7 to 32) after treatment were analysed using COMET and sperm chromatin structure (SCSA) assays. The treatment induced a stress response in both the testis and the epididymis that was associated with reduced expression of the cold inducible RNA binding protein (Cirp) and an increase in germ cell apoptosis (Apotag positive cells). Although spermatozoa present in the epididymis at the time of heating contained correctly packaged DNA, its integrity was compromised by heat stress. In addition, although some germ cells, which were present within the testis at the time of heat stress, were removed by apoptosis, many germ cells completed their development and were recovered as motile spermatozoa with damaged DNA. In conclusion, these data demonstrate that scrotal heat stress can compromise the DNA integrity of spermatozoa and this may have clinical implications for patients undergoing IVF and intra-cytoplasmic sperm injection (ICSI).
Porcine embryo development and fragmentation and their relation to apoptotic markers: a cinematographic and confocal laser scanning microscopic study
Authors: Mateusen Bart , Van Soom Ann , Maes Dominiek G D , Donnay Isabelle , Duchateau Luc , Lequarre Anne-Sophie
Published: March 2005

Porcine embryo selection prior to transfer is mainly influenced by morphological criteria. However, the relationship between embryonic morphology, developmental potential and cell death by apoptosis in porcine embryos is still unclear. The aim of this study was to establish embryo quality parameters for in vivo fertilised porcine embryos based on timing of development in vitro, embryo morphology and the presence of apoptosis. The kinetics of development and morphological parameters were investigated in a time-lapse cinematographic experiment. Possible links between embryo morphology and apoptosis were examined via a confocal laser scanning experiment, analysing nuclear changes, annexin V and terminal dUTP nick-end labelling. The timing of early cleavages was firmly linked to embryo developmental competence in vitro. Attainment of at least the 5-cell stage before 77 h post insemination and attainment of the morula stage before 102 h post insemination significantly increased the odds for reaching the early blastocyst stage. Overall, a negative effect of fragmentation percentage and fragmentation pattern on subsequent embryonic development was observed, but the developmental potential of embryos experiencing slight fragmentation (0–5%) was not different from embryos without fragmentation. Correlations detected between developmental arrest and fragmentation, and fragmentation and apoptosis were 0.60 and 0.87 (P < 0.05) respectively. Only a minority of the embryos arrested between the 1- and 4-cell stage displayed biochemical characteristics of apoptosis. Consequently, a significant correlation (0.57) between developmental arrest and apoptosis could only be established for embryos arrested after embryonic genome activation.
Oocytes recovered from cows treated with retinol become unviable as blastocysts produced in vitro
Authors: Hidalgo C , Díez C , Duque P , Prendes J M , Rodríguez A , Goyache F , Fernández I , Facal N , Ikeda S , Alonso-Montes C , Gómez E
Published: March 2005

Retinoids have been shown to enhance developmental competence of the oocyte in cattle, sheep and pigs. In this study we investigated whether exogenous retinol stimulates the bovine oocyte during its intrafollicular growth and the time limits of exposure to exogenous retinol. In addition, we also determined the efficiency of ovum pick-up techniques in combination with retinol treatment and the viability of embryos after transfer to recipients. In Experiment 1, heifers were injected with retinol or vehicle, and concentrations of retinol in the blood were analysed on Day 0 (prior to injection), Day 1 and, together with follicular fluid, Day 4. Blood retinol increased by Day 1 and cleared on Day 4, but retinol remained higher within the follicle. In Experiment 2, oocyte donors were injected weekly with retinol or vehicle four times during a twice-per-week cycle of eight recovery sessions (starting 4 days before the first session), followed by a second eight-session cycle without treatment. Oocytes recovered were fertilized and culturedin vitro.Retinol treatment yielded higher numbers of low-quality oocytes throughout, although retinol measured during cycles did not change. Total oocytes, and morulae and blastocyst rates, increased during the first five sessions following treatment with retinol. As previously shown with oocytes from slaughterhouse ovaries, retinoic acid stimulated blastocyst development. Following transfer to recipients, blastocysts from oocytes exposed to retinol were unable to establish pregnancy. Our study confirms the existence of an effect of retinol on the intrafollicular oocyte in the cow and provides evidence regarding the teratogenic effect of retinol.
In vivo effects of pregnancy-associated plasma protein-A, activin-A and vascular endothelial growth factor on other follicular-fluid factors during follicle deviation in mares
Authors: Ginther O J , Gastal E L , Gastal M O , Beg M A
Published: March 2005

During a follicular wave in mares, the two largest follicles (F1 and F2) begin to deviate in diameter when F1 is a mean of 22.5 mm. The intrafollicular effects of pregnancy-associated plasma protein-A (PAPP-A), IGF-I, activin-A and vascular endothelial growth factor (VEGF) on other follicular-fluid factors during deviation were studied. In four treated groups (n= 7/group), a single dose of one of the four factors was injected into F2 when F1 was ≥20.0 mm (expected beginning of deviation). In a control group (n= 7), F2 was injected with vehicle. One day after treatment, a sample of follicular fluid was taken from F1 and F2 of the control group and from F2 of the treated groups and was assayed for free IGF-I, oestradiol, androstenedione, activin-A, inhibin-A, follistatin and VEGF. In the control group, the means for all end points were significantly greater in F1 than in F2, except that concentrations of androstenedione were lower in F1 than in F2. The treatment effects for F2 were significant as follows: PAPP-A increased the concentrations of free IGF-I, inhibin-A, follistatin and VEGF and decreased the concentrations of androstenedione; IGF-I increased the concentration of inhibin-A and decreased the concentration of androstenedione; activin-A decreased the concentrations of follistatin and androstenedione and increased the diameter of F2; and VEGF increased the concentration of IGF-I and decreased the concentration of androstenedione. These results support the hypotheses that during deviation in mares PAPP-A increases the follicular-fluid concentrations of free IGF-I, follistatin responds to changes in follicular-fluid concentrations of activin-A, and VEGF affects the concentrations of other follicular-fluid factors.
Estradiol and leptin as conditional prognostic IVF markers
Authors: Anifandis G , Koutselini E , Louridas K , Liakopoulos V , Leivaditis K , Mantzavinos T , Sioutopoulou D , Vamvakopoulos N
Published: March 2005

We studied the concentration of serum estradiol and serum and follicular fluid leptin in 200 women undergoing their first in vitro fertilization with embryo transfer (IVF-ET) program at the time of human chorionic gonadotrophin administration and oocyte retrieval, in an attempt to assess their concerted role on embryo quality and the prognosis of IVF outcome. Low serum (46.49 ± 8.4 ng/ml) and follicular fluid (52 ± 9.8 ng/ml) leptin levels were associated with a high number of ‘good-quality’ embryos (73.6%) and high implantation (11.2%) and pregnancy (35.8%) rates and were observed in women with normal peak estradiol levels of between 1000 and 2000 pg/ml. It appears that leptin and estradiol interact coordinately in a concentration-dependent manner to control IVF outcome. Further studies will be required to substantiate and clarify the mechanism of proposed conditional interaction between the two hormonal systems.
The PATE gene is expressed in the accessory tissues of the human male genital tract and encodes a secreted sperm-associated protein
Authors: Soler-García Ángel A , Maitra Rangan , Kumar Vasantha , Ise Tomoko , Nagata Satoshi , Beers Richard , Bera Tapan K , Pastan Ira
Published: March 2005

ThePATEgene is expressed in prostate and testis. To determine if PATE is expressed in other accessory tissues of the male genital tract, RT-PCR of the epididymis and seminal vesicle was performed. PATE mRNA was highly expressed in the epididymis and seminal vesicle.In situhybridization of the testis showed PATE mRNA is strongly expressed in the spermatogonia. ThePATEgene encodes a 14-kDa protein with a predicted signal sequence and a cleavage site between residues G21 and S22. To determine if PATE is a secreted protein, 293T cells were transfected with a pcDNA-PATE-myc-His plasmid and protein immunoprecipitated with anti-myc monoclonal antibody. Western blot analysis showed the presence of PATE-myc-His protein was in the medium and the cell lysate. Confocal microscopy demonstrated that PATE-myc-His protein is found in the endoplasmic reticulum. The polyclonal antibody SOL-1 was generated by immunization of rabbits with recombinant PATE protein expressed and purified fromEscherichia coli.Western blots were performed on extracts of prostate, testis, seminal vesicle and ejaculated spermatozoa, but PATE protein was only detected in the spermatozoa. Immunostaining of sperm smears revealed that PATE is located in a band-like pattern in the sperm head. Our data indicate that PATE is made by various sexual accessory tissues and secreted into the semen where it becomes associated with sperm, suggesting that PATE is a novel sperm-associated protein with a possible role in mammalian sperm maturation.
Have Adirondack Stream Fish Populations Changed in Response to Decreases in Sulfate Deposition?
Authors: Simonin Howard A. , Colquhoun James R. , Paul Eric A. , Symula John , Dean Howard J.
Published: March 2005

Fish populations in 36 Adirondack headwater streams were surveyed by electrofishing in fall 1979 and 1999; water chemistry samples were collected during spring 1980 and 2000. The surveys were designed to evaluate impacts of acidity on stream fish populations and also to document any changes that had occurred between the two studies. The acid‐neutralizing capacity and pH of the streams were not significantly different between 1980 and 2000, although in a different grouping of 37 Adirondack streams, calcium levels were significantly lower in spring 2000 than in spring 1982. More fish and fish species were collected in 1999 than 1979. However, because changes occurred in streams with relatively high pH (>6.0) as well as in low‐pH streams, increases in fish caught may have been partly the result of improved electrofishing efficiency in 1999. In both 1999 and 1979, streams with spring pH less than 5.0 supported fewer fish, fewer salmonids, and fewer fish species than streams with higher pH. No young‐of‐year brook trout Salvelinus fontinalis were found in streams with a spring pH less than 4.98. Sensitive and acid‐impacted streams continue to exist in the Adirondack region even though sulfate deposition has decreased since the 1990 Clean Air Act Amendments.
Abnormalities in Larvae from the Once‐Largest Pacific Herring Population in Washington State Result Primarily from Factors Independent of Spawning Location
Authors: Hershberger P. K. , Elder N. E. , Wittouck J. , Stick K. , Kocan R. M.
Published: March 2005

Among larvae from populations of Pacific herring Clupea pallasii in Washington State, those from Cherry Point have consistently demonstrated abnormalities indicative of distress, including low weights and lengths at hatch, increased prevalences of skeletal abnormalities, and shorter survival times in food deprivation studies. The biomass of adult, prespawn Pacific herring at Cherry Point declined from 13,606 metric tons in 1973 to a record low 733 metric tons in 2000. However, correlation of larval abnormalities with adult recruitment was weak, indicating that the larval abnormalities did not directly cause the decline. Larval abnormalities originated primarily from factors independent of conditions at the spawning location because they were not reproduced by incubation of foreign zygotes along the Cherry Point shoreline but were reproduced after the development of indigenous zygotes in controlled laboratory conditions. Although the precise cause of the abnormalities was not determined, recent zoographic trends in elevated natural mortality among adult Pacific herring and resulting reduced age structures may be involved.
The Response of Lake Trout to Manual Tracking
Authors: Blanchfield Paul J. , Flavelle Lori S. , Hodge Tristan F. , Orihel Diane M.
Published: March 2005

The use of telemetry is widespread in fisheries research, and manual tracking of fish is considered acceptable for data collection. However, it has never been shown whether the use of boats with powered engines, which is common in manual tracking, influences the distribution and behavior of fish. We examined whether general boat traffic or focused manual tracking activity altered movement patterns of adult lake trout Salvelinus namaycush in a small boreal lake at the Experimental Lakes Area of northwestern Ontario, Canada. In the summer and fall of 2002, we used automated fish positioning systems to compare the behavior of lake trout during 1‐h disturbance periods (boat traffic or manual tracking) with behavior in the preceding 1‐h baseline periods (no disturbance). In addition, we compared behavioral differences of lake trout during disturbance and baseline periods (experimental trials) with a similar period of time when no boats were on the lake (control trials). This comparison allowed us to determine whether the observed changes in behavior during normal boat traffic or manual tracking were within the natural range of variation. Overall, we observed no effect of boat traffic or manual tracking on the depth, speed, and path predictability of lake trout. Similarly, the changes in lake trout behavior between the disturbance and baseline periods of the experimental trials were all within the natural range determined by control trials. The response of lake trout to manual tracking was not related to their proximity to the motorboat, both when lake trout were in deep water (6 m; summer) and when they were in shallow water (2 m; fall spawning season). The lack of significance of the relationship between patterns of fish behavior and manual tracking activity provides support for the continued use of this method in fisheries research.
The Obesity Epidemic as Harbinger of a Metabolic Disorder Epidemic: Trends in Overweight, Hypercholesterolemia, and Diabetes Treatment in Geneva, Switzerland, 1993–2003
Authors: Morabia Alfredo , Costanza Michael C.
Published: March 2005

Increases in obesity, hypercholesterolemia, and diabetes may be under way in Europe. We have reported the only data available from the 1990s for continuous monitoring of chronic disease risk factors in random samples of a general European population. In random surveys (1993–2003) of 6164 men and 6107 women in Geneva, overweight and obesity combined increased in both men and women; hypercholesterolemia prevalence also rose; diabetes treatment increased in men. Only population-based interventions can prevent the impending epidemic of obesity-related disorders.
Father’s Occupational Group and Daily Smoking During Adolescence: Patterns and Predictors
Authors: Droomers Mariël , Schrijvers Carola T.M. , Casswell Sally , Mackenbach Johan P.
Published: March 2005

Objectives. We investigated the relationship among father’s occupational group, daily smoking, and smoking determinants in a cohort of New Zealand adolescents.

Methods. The longitudinal Multidisciplinary Health and Development Study provided information on adolescents’ self-reported smoking behavior and potential predictors of smoking, such as social and material factors, personality characteristics, educational achievement, and individual attitudes and beliefs regarding smoking. Longitudinal logistic generalized estimating equation analyses were used.

Results. Adolescents whose fathers were classified in the lowest-status occupational group were twice as likely as those whose fathers occupied the highest-status occupational group to be daily smokers. This high risk of daily smoking among the adolescents from the lowest occupational group was largely predicted by their lower intelligence scores and by the higher prevalence of smoking among fathers and friends .

Conclusions. To prevent socioeconomic differences in smoking, school-based interventions should seek to prevent smoking uptake among adolescents, particularly those of lower socioeconomic status. Programs need to provide positive, nonsmoking role models consonant with the culture and norms of lower-socioeconomic-status groups. Adolescents need to acquire resistance skills and protective behaviors against social pressure and influences.
Childhood Sexual Abuse and Age at Initiation of Injection Drug Use
Authors: Ompad Danielle C. , Ikeda Robin M. , Shah Nina , Fuller Crystal M. , Bailey Susan , Morse Edward , Kerndt Peter , Maslow Carey , Wu Yingfeng , Vlahov David , Garfein Richard , Strathdee Steffanie A.
Published: March 2005

Objectives. We examined the relation between childhood sexual abuse and injection drug use initiation among young adult injection drug users.

Methods. We used mixed effect linear models to compare age at first injection among 2143 young injection drug users by first sexual abuse age categories.

Results. The participants were predominantly male (63.3%) and White (52.8%). Mean age and age at first injection were 23.7 and 19.6 years, respectively; 307 participants (14.3%) reported childhood sexual abuse. After adjustment for gender, race/ethnicity, noninjection drug use before first injection drug use, and recruitment site, childhood sexual abuse was independently associated with younger age at first injection.

Conclusions. Childhood sexual abuse was associated with earlier initiation of injection drug use. These data emphasize the need to integrate substance abuse prevention with postvictimization services for children and adolescents.
Effects of Race, Neighborhood, and Social Network on Age at Initiation of Injection Drug Use
Authors: Fuller Crystal M. , Borrell Luisa N. , Latkin Carl A. , Galea Sandro , Ompad Danielle C. , Strathdee Steffanie A. , Vlahov David
Published: March 2005

Objectives. We investigated individual- and neighborhood-level factors associated with adolescent initiation of injection drug use.

Methods. Injection drug users (IDUs) who had been injecting 2 to 5 years underwent HIV testing and completed a sociobehavioral risk survey. Modeling techniques accounting for intraneighborhood correlations were used in data analyses.

Results. Adolescent-initiating IDUs were less likely than adult-initiating IDUs to report high-risk sex and injection behaviors and more likely to report high-risk networks. African American IDUs from neighborhoods with large percentages of minority residents and low adult educational levels were more likely to initiate injection during adolescence than White IDUs from neighborhoods with low percentages of minority residents and high adult education levels.

Conclusions. Racial segregation and neighborhood-level educational attainment must be considered when drawing inferences about age at initiation of injection drug use and related high-risk behaviors.
Racial/Ethnic Variation in Functional and Self-Reported Health
Authors: Wu Zheng , Schimmele Christoph M.
Published: March 2005

Objectives. We investigated whether racial/ethnic health disparities exist in Canada and whether socioeconomic or behavioral differences between racial/ ethnic minorities and nonminorities account for such disparities.

Methods. We used data from the National Population Health Survey, conducted by Statistics Canada in 1996 and 1997. We used regression models to examine differences in functional and self-reported health.

Results. Our study found no association between socioeconomic or behavioral differences and racial/ethnic health disparities. There was no clear pattern between racial/ethnic minority status and health.

Conclusions. The state can play an important role in health outcomes, and public commitment to accessible health care may explain why socioeconomic status and health behaviors are weak indicators of racial/ethnic health variation in Canada.
The Epidemiology of Alcohol, Marijuana, and Cocaine Use Among Mexican American, Puerto Rican, Cuban American, and Other Latin American Eighth-Grade Students in the United States: 1991–2002
Authors: Delva Jorge , Wallace John M. , O’Malley Patrick M. , Bachman Jerald G. , Johnston Lloyd D. , Schulenberg John E.
Published: March 2005

Objectives. We compared trends in and correlates of marijuana use, cocaine use, and heavy alcohol use for adolescents of Mexican American, Puerto Rican, Cuban, and other Latin American heritage in the United States.

Methods. We used/examined data from nationally representative samples of eighth-grade Hispanic students who participated in the Monitoring the Future study during the years 1991–2002 (n=24235).

Results. Drug use was significantly higher among boys and adolescents of almost all Hispanic ethnicities who did not live with both parents. In addition, drug use differed considerably according to ethnic group on language first spoken, parental education, urbanicity, and region.

Conclusions. A better understanding of the homogeneity and heterogeneity of drug use patterns within and between Hispanic groups should assist in the development of prevention programs.
Using Surveillance Data to Develop and Disseminate Local Childhood Lead Poisoning Screening Recommendations: Miami—Dade County’s Experience
Authors: Trepka Mary Jo
Published: March 2005

Before 1999, few children in Florida’s Miami–Dade County were being screened for lead poisoning. To improve screening rates, the county’s department of health developed screening recommendations and a screening tool using surveillance and census data and disseminated these materials to primary care providers. Each year, recommendations have been reviewed to assess their sensitivity, and revised recommendations have been disseminated to health care providers.

The percentage of children 6 years or younger screened in Florida who reside in Miami–Dade County increased from 4.1% in 1998 to 20.3% in 2002. Analysis and dissemination of blood lead surveillance data not only guide development of screening recommendations but also educate health care providers regarding the importance of childhood screening.
Neighborhood Racial Composition, Neighborhood Poverty, and the Spatial Accessibility of Supermarkets in Metropolitan Detroit
Authors: Zenk Shannon N. , Schulz Amy J. , Israel Barbara A. , James Sherman A. , Bao Shuming , Wilson Mark L.
Published: March 2005

Objectives. We evaluated the spatial accessibility of large “chain” supermarkets in relation to neighborhood racial composition and poverty.

Methods. We used a geographic information system to measure Manhattan block distance to the nearest supermarket for 869 neighborhoods (census tracts) in metropolitan Detroit. We constructed moving average spatial regression models to adjust for spatial autocorrelation and to test for the effect of modification of percentage African American and percentage poor on distance to the nearest supermarket.

Results. Distance to the nearest supermarket was similar among the least impoverished neighborhoods, regardless of racial composition. Among the most impoverished neighborhoods, however, neighborhoods in which African Americans resided were, on average, 1.1 miles further from the nearest supermarket than were White neighborhoods.

Conclusions. Racial residential segregation disproportionately places African Americans in more-impoverished neighborhoods in Detroit and consequently reduces access to supermarkets. However, supermarkets have opened or remained open close to middle-income neighborhoods that have transitioned from White to African American. Development of economically disadvantaged African American neighborhoods is critical to effectively prevent diet-related diseases among this population.
Heat-Related Fatalities in North Carolina
Authors: Mirabelli Maria C. , Richardson David B.
Published: March 2005

We used medical examiner’s records to identify heat-related fatalities (N=161) that occurred during the period January 1, 1977, to December 31, 2001, in North Carolina. Estimates of the population at risk were derived from US census data. Annual fatality rates increased with increases in average summer temperature and with the number of days per year at 90°F or higher. Of the occupational heat-related fatalities (n=40), 45% occurred among farm laborers, many of whom died unnoticed and without medical attention.
The Seattle-King County Healthy Homes Project: A Randomized, Controlled Trial of a Community Health Worker Intervention to Decrease Exposure to Indoor Asthma Triggers
Authors: Krieger James W. , Takaro Tim K. , Song Lin , Weaver Marcia
Published: March 2005

Objectives. We assessed the effectiveness of a community health worker intervention focused on reducing exposure to indoor asthma triggers.

Methods. We conducted a randomized controlled trial with 1-year follow-up among 274 low-income households containing a child aged 4–12 years who had asthma. Community health workers provided in-home environmental assessments, education, support for behavior change, and resources. Participants were assigned to either a high-intensity group receiving 7 visits and a full set of resources or a low-intensity group receiving a single visit and limited resources.

Results. The high-intensity group improved significantly more than the low-intensity group in its pediatric asthma caregiver quality-of-life score (P=.005) and asthma-related urgent health services use (P=.026). Asthma symptom days declined more in the high-intensity group, although the across-group difference did not reach statistical significance (P= .138). Participant actions to reduce triggers generally increased in the high-intensity group. The projected 4-year net savings per participant among the high-intensity group relative to the low-intensity group were $189–$721.

Conclusions. Community health workers reduced asthma symptom days and urgent health services use while improving caregiver quality-of-life score. Improvement was greater with a higher-intensity intervention.
Talking About Public Health: Developing America’s “Second Language”
Authors: Wallack Lawrence , Lawrence Regina
Published: March 2005

The mission of public health—improving the health of populations—is difficult to advance in public discourse because a language to express the values animating that mission has not been adequately developed. Following on the work of Robert Bellah, Dan Beauchamp, and others, we argue that the first “language” of American culture is individualism.

A second American language of community—rooted in egalitarianism, humanitarianism, and human interconnection—serves as the first language of public health. These values resonate with many Americans but are not easily articulated. Consequently, reductionist, individualistic understandings of public health problems prevail.

Advancing the public health approach to the nation’s health challenges requires invigorating America’s second language by recognizing the human interconnection underlying the core social justice values of public health.
The National Public Health Leadership Institute: Evaluation of a Team-Based Approach to Developing Collaborative Public Health Leaders
Authors: Umble Karl , Steffen David , Porter Janet , Miller Delesha , Hummer-McLaughlin Kelley , Lowman Amy , Zelt Susan
Published: March 2005

Recent public health literature contains calls for collaborative public health interventions and for leaders capable of guiding them. The National Public Health Leadership Institute aims to develop collaborative leaders and to strengthen networks of leaders who share knowledge and jointly address public health problems. Evaluation results show that completing the institute training increases collaborative leadership and builds knowledge-sharing and problem-solving networks. These practices and networks strengthen interorganizational relationships, coalitions, services, programs, and policies. Intensive team-and project-based learning are key to the program’s impact.
Integrating Social Theory Into Public Health Practice
Authors: Potvin Louise , Gendron Sylvie , Bilodeau Angèle , Chabot Patrick
Published: March 2005

The innovative practice that resulted from the Ottawa Charter challenges public health knowledge about programming and evaluation. Specifically, there is a need to formulate program theory that embraces social determinants of health and local actors’ mobilization for social change. Likewise, it is imperative to develop a theory of evaluation that fosters reflexive understanding of public health programs engaged in social change.

We believe advances in contemporary social theory that are founded on a critique of modernity and that articulate a coherent theory of practice should be considered when addressing these critical challenges.
From Neurons to King County Neighborhoods: Partnering to Promote Policies Based on the Science of Early Childhood Development
Authors: Horsley Kathryn , Ciske Sandra J.
Published: March 2005

A diverse community partnership in the Seattle area developed a policy agenda based on science, organized community support, and committed to monitor policy changes. It found that public health agencies are well positioned to develop a common knowledge base on early childhood development and to initiate community coalitions promoting policies to strengthen environments.

It was challenging to maintain participants’ focus on environments over time. Providing access to conditions that promote optimal development for all children will require ongoing commitment and alignment of many sectors to move political will and mobilize for change.
Healthy Eating and Exercising to Reduce Diabetes: Exploring the Potential of Social Determinants of Health Frameworks Within the Context of Community-Based Participatory Diabetes Prevention
Authors: Schulz Amy J. , Zenk Shannon , Odoms-Young Angela , Hollis-Neely Teretha , Nwankwo Robin , Lockett Murlisa , Ridella William , Kannan Srimathi
Published: March 2005

Objectives. We examined a community-based participatory diabetes intervention to identify facilitators of and barriers to sustained community efforts to address social factors that contribute to health.

Methods. We conducted a case study description and analysis of the Healthy Eating and Exercising to Reduce Diabetes project in the theoretical context of a conceptual model of social determinants of health.

Results. We identified several barriers to and facilitators of analysis of social determinants of a community-identified disease priority (in this case, diabetes). Barriers included prevailing conceptual models, which emphasize health behavioral and biomedical paradigms that exclude social determinants of health. Facilitating factors included (1) opportunities to link individual health concerns to social contexts and (2) availability of support from diverse partners with a range of complementary resources.

Conclusions. Partnerships that offer community members tangible resources with which to manage existing health concerns and that integrate an analysis of social determinants of health can facilitate sustained engagement of community members and health professionals in multilevel efforts to address health disparities.
African Americans’ Access to Healthy Food Options in South Los Angeles Restaurants
Authors: Lewis LaVonna Blair , Sloane David C. , Nascimento Lori Miller , Diamant Allison L. , Guinyard Joyce Jones , Yancey Antronette K. , Flynn Gwendolyn
Published: March 2005

Objectives. We examined availability and food options at restaurants in less affluent (target area) and more affluent (comparison area) areas of Los Angeles County to compare residents’ access to healthy meals prepared and purchased away from home. We also considered environmental prompts that encourage the purchase of various foods.

Methods. We designed an instrument to assess the availability, quality, and preparation of food in restaurants. We also assessed advertisements and promotions, cleanliness, and service for each restaurant. We assessed 659 restaurants: 348 in the target area and 311 in the comparison area.

Results. The nutritional resource environment in our target area makes it challenging for residents to eat healthy away from home. Poorer neighborhoods with a higher proportion of African American residents have fewer healthy options available, both in food selections and in food preparation; restaurants in these neighborhoods heavily promote unhealthy food options to residents.

Conclusions. Environment is important in understanding health status: support for the healthy lifestyle associated with lower risks for disease is difficult in poorer communities with a higher proportion of African American residents.
Manifold Restraints: Liberty, Public Health, and the Legacy of Jacobson v Massachusetts
Authors: Colgrove James , Bayer Ronald
Published: March 2005

February 2005 marks the centenary of one of the most important pieces of public health jurisprudence, the US Supreme Court case of Jacobson v Massachusetts, which upheld the authority of states to pass compulsory vaccination laws. The Court’s decision articulated the view that the freedom of the individual must sometimes be subordinated to the common welfare.

We examined the relationship between the individual and society in 20th-century public health practice and law and the ways that compulsory measures have been used to constrain personal liberty for the sake of protecting the public health. (Am J Public Health.
Computational Aspects of Sundt's Generalized Class
Authors: Panjer Harry H. , Wang Shaun
Published: March 2005

Some practical applications of Sundt's (1992) generalized class of counting distributions are discussed. The numerical stabilities of some recursive formulas in Sundt's class are investigated.
On Some Properties of de Pril Transforms of Counting Distributions
Authors: Sundt Bjørn
Published: March 2005

In this paper we study a transform introduced by De Pril (1989) for recursive evaluation of convolutions of counting distributions with a positive probability in zero. We discuss some cases where the evaluation of this transform is simplified and relate the transform to infinitely divisible distributions. Finally we discuss an algorithm presented by Dhaene & Vandebroek (1994) for recursive evaluation of convolutions.
The Effect of the Retention Limit on the Risk Reserve
Authors: Centeno Maria de Lourdes
Published: March 2005

This paper is devoted to the study of the initial reserve, as a function of the retention limit, needed to assure that the probability of ruin, at the end of a certain period of time, is not higher than an agreed value, for an excess of loss treaty. To assess the probability of ruin, the normal and the normal power approximation are used. It is shown that the initial reserve is not in general an increasing function of the retention, having a minimum under fair assumptions.
The Present Value of a Series of Cashflows: Convergence in a Random Environment
Authors: Cairns Andrew J. G.
Published: March 2005

The present paper considers the present value, Z(t), of a series of cashflows up to some time t. More specifically, the cashflows and the interest rate process will often be stochastic and not necessarily independent of one another or through time. We discuss under what circumstances Z(t) will converge almost surely to some finite value as t→∞. This problem has previously been considered by Dufresne (1990) who provided a sufficient condition for almost sure convergence of Z(t) (the Root Test) and then proceeded to consider some specific examples of such processes. Here, we develop Dufresne's work and show that the sufficient condition for convergence can be proved to hold for quite a general class of model which includes the growing number of Office Models with stochastic cashflows.
On the Estimation of the Credibility Factor: A Bayesian Approach
Authors: Schnieper René
Published: March 2005

In practical applications of Credibility Theory the structure parameters usually have to be estimated from the data. This leads to an estimator of the a posteriori mean which is often biased and where the credibility factor depends on the data. A more coherent approach to the problem would be to also treat the unknown parameters as random variables and to simultaneously estimate the a posteriori mean and the structure parameters. Different statistical models are proposed which allow for such a solution. These models all lead to an estimation of the posterior mean which is a weighted average of the prior mean and of the observed mean, the weights depending on the observations.
A portfolio of endowment policies and its limiting distribution
Authors: Parker Gary
Published: March 2005

Two methods for approximating the limiting distribution of the present value of the benefits of a portfolio of identical endowment insurance contracts are suggested. The model used assumes that both future lifetimes and interest rates are random. The first method is similar to the one presented in Parker (1994b). The second method is based on the relationship between temporary and endowment insurance contracts.
Recursions for certain bivariate counting distributions and their compound distributions
Authors: Hesselager Ole
Published: March 2005

We consider three classes of bivariate counting distributions and the corresponding compound distributions. For each class we derive a recursive algorithm for calculating the bivariate compound distribution.
Credibility and Persistency
Authors: Young Virginia R.
Published: March 2005

Policyholders often decide to buy, renew, or cancel insurance based on the premium charged by the insurer compared with what they expect their claims will be. It is important for actuaries to consider the persistency of policyholders because the financial well-being of the insurer depends on spreading its risk over a large book of business. We use statistical decision theory to develop premium formulas that account for the past experience of a given policyholder, the experience of the entire collection of policyholders, and the likelihood of the policyholder renewing with or buying from a given insurer, that is, persistency.

We assume that the persistency of policyholders depends on the arithmetic difference between the premium charged and their anticipated claims. We extend the work of Taylor (1975) in which he obtains linear credibility formulas by minimizing loss functions that incorporate the persistency of policyholders. We consider Taylor's loss functions and other objective functions, including those that account for the amount of business the insurer writes or renews.