Effect of dexamethasone treatment on the immune response of Gulf Coast Native lambs to Haemonchus contortus infection

Neonatal and weaner Gulf Coast Native (Native) lambs were studied to determine whether an immunological basis underlies their natural resistance to Haemonchus contortus infection. Neonatal Native lambs (n = 8) and weaner Native lambs (n = 15) were randomly assigned to a treatment or a control group. Lambs in the treatment group received dexamethasone by intramuscular injection three times a week for 10 weeks (neonatal) and 15 weeks (weaners). All lambs were monitored for fecal egg count (FEC), blood packed cell volume (PCV), and white blood cell differential counts on a weekly basis for the duration of the studies. Neonatal lambs were kept on pasture with their dams and weaner lambs were dewormed at weaning and kept in pens where they received trickle infections. Serum antibody titers to H. contortus whole worm antigen (WWA) were determined using ELISA. Lymphocyte proliferation assays on peripheral blood mononuclear cells (PBMC) were done to assess lymphocyte function. All lambs were vaccinated with killed Brucella abortus strain 19 to assess the effect of dexamethasone treatment on antibody response. All lambs were necropsied at the end of each study to recover the contents of the gastrointestinal tract for nematode enumeration and identification. The results showed that mean FEC and mean PCV of the treatment group was significantly higher and lower, respectively, than in the control group in both neonatal and weaner lambs from weeks 6 and 5, respectively. At necropsy, total nematode count was significantly higher in treatment groups than in the control groups. Serum antibody titers to H. contortus WWA were significantly lower in treated groups than in control groups. Treatment groups showed a consistent depression in lymphocyte percentage being significantly lower from week 6 in both neonatal and weaner lambs. No differences were found in the response of PBMC to mitogen stimulation between the groups. Lambs in the control groups showed strong positive brucellosis card tests and the treatment groups did not. Dexamethasone treatment resulted in depression of the immune response and loss of natural resistance of Native lambs to H. contortus infection. The results of these studies suggest that some aspects of the immune response may underlie the natural resistance of Native sheep to H. contortus infection.

Efficiency of feeding Duddingtonia flagrans chlamydospores to grazing ewes on reducing availability of parasitic nematode larvae on pasture

Gastrointestinal nematodes are of concern in sheep production because of production and economic losses. Control of these nematodes is primarily based on the use of anthelmintic treatment and pasture management. The almost exclusive use of anthelmintic treatment has resulted in development of anthelmintic resistance which has led to the need for other parasite control options to be explored. The blood sucking abomasal parasitic nematode Haemonchus contortus causes severe losses in small ruminant production in the warm, humid sub-tropic and tropics. This study evaluated the effectiveness of a nematode trapping fungus, Duddingtonia flagrans, in reducing availability of parasitic nematode larvae, specifically H. contortus, on pasture. Chlamydospores of D. flagrans were mixed with a supplement feed which was fed daily to a group of crossbred ewes for the duration of the summer grazing season. A control group was fed the same supplement feed without chlamydospores. A reduction in infective larval numbers was observed in fecal cultures of the fungus-fed group. Herbage samples from the pasture grazed by the fungus-fed group also showed a reduction in infective larvae. There were no significant (P > 0.05) differences in overall fecal egg count, packed cell volume or animal weight between fungus-fed and control groups. Tracer animals were placed on the study pastures at the end of the study to assess pasture infectivity. Although tracer animals were only two per group, those that grazed with the fungus-fed group had substantially reduced (96.8%) nematode burdens as compared to those from the control group pasture. Results demonstrated that the fungus did have activity against nematode larvae in the feces which reduced pasture infectivity and subsequently nematode burdens in tracer animals. This study showed that D. flagrans, fed daily to grazing ewes, was an effective biological control agent in reducing a predominantly H. contortus larval population on pasture.

Growth and yield responses of potato to mixtures of carbon dioxide and ozone

Elevated carbon dioxide (CO2) concentrations in the atmosphere can stimulate plant growth and yield, whereas ground-level ozone (O3) concentrations cause the opposite effect in many areas of the world. Recent experiments show that elevated CO2 can protect some plants from O3 stress, but this has not been tested for most crop species. Our objective was to determine if elevated CO2 protects Irish potato (Solanum tuberosum L.) from foliar injury and suppression of growth and yield caused by O3. An O3-resistant cultivar (Superior) and an O3-sensitive cultivar (Dark Red Norland) were exposed from within 10 d after emergence to maturity to mixtures of three CO2 and three O3 treatments in open-top field chambers. The three CO2 treatments were ambient (370 microL L(-1)) and two treatments with CO2 added to ambient CO2 for 24 h d(-1) (540 and 715 microL L(-1)). The O3 treatments were charcoal-filtered air (15 nL L(-1)), nonfiltered air (45 nL L(-1)), and nonfiltered air with O3 added for 12 h d(-1) (80 nL L(-1)). Elevated O3 and CO2 caused extensive foliar injury of Dark Red Norland, but caused only slight injury of Superior. Elevated CO2 increased growth and tuber yield of both cultivars, whereas elevated O3 generally suppressed growth and yield, mainly of Dark Red Norland. Elevated CO2 appeared to protect Dark Red Norland from O3-induced suppression of shoot, root, and tuber weight as measured at midseason but did not protect either cultivar from O3 stress at the final harvest. The results further illustrate the difficulty in predicting effects of O3 + CO2 mixtures based on the effects of the individual gases.

Relative resistance of Dorper crossbred ewes to gastrointestinal nematode infection compared with St. Croix and Katahdin ewes in the southeastern United States

A study was conducted to evaluate relative resistance of Dorper crossbred (DO), Katahdin (KA), St. Croix (SC), and Hampshire (HA) ewes to natural and experimental gastro-intestinal (GI) nematode infection over a 20-month period. The objective of Experiment 1 was to evaluate breeds for resistance to infection acquired naturally from mixed grass pastures. In Year 1 (May-December 2000) de-worming of ewes occurred during wet, hot conditions in July and during late pregnancy in December. In Year 2 (January-December 2001), ewes were de-wormed after fecal egg count (FEC) for a breed group rose above 1000 eggs per gram (epg) or after blood packed cell volume (PCV) of an individual ewe fell below 20. FEC was determined every 28 days and PCV every 14-28 days. In both the years, ewes were pastured together, except during the 28-days breeding periods, on tall fescue, bermudagrass, or ryegrass, and rotated among pastures dependent on forage availability. Ewes were in good or excellent condition (body condition score of 3-4 out of 5) throughout the study. The objective of Experiment 2 was to evaluate the breeds for relative resistance to an experimental infection with Haemonchus contortus infective larvae. Both PCV and FEC were determined every 7 days from 14 to 42 days after inoculation with 30000 infective larvae per ewe. In Experiment 1, Year 1, FEC was slightly greater and PCV was lower from July to September in DO ewes (breed x time, P<0.001). In Year 2, de-worming occurred 14 days later in DO ewes compared with other breed types. Otherwise PCV and FEC were similar among the hair breeds and higher and lower, respectively, compared with HA ewes (breed x time, P<0.001). In Experiment 2, FEC and PCV were similar among hair breeds; FEC was lower and PCV higher in hair breeds compared with that of HA ewes (P<0.01). Relative resistance of mature Dorper crossbred ewes was comparable to that of Katahdin and St. Croix ewes and superior to that of Hampshire ewes.

Growth and yield responses of snap bean to mixtures of carbon dioxide and ozone

Elevated CO2 concentrations expected in the 21st century can stimulate plant growth and yield, whereas tropospheric O3 suppresses plant growth and yield in many areas of the world. Recent experiments showed that elevated CO2 often protects plants from O3 stress, but this has not been tested for many important crop species including snap bean (Phaseolus vulgaris L.). The objective of this study was to determine if elevated CO2 protects snap bean from O3 stress. An O3-tolerant cultivar (Tenderette) and an O3-sensitive selection (S156) were exposed from shortly after emergence to maturity to mixtures of CO2 and O3 in open-top field chambers. The two CO2 treatments were ambient and ambient with CO2 added for 24 h d(-1) resulting in seasonal 12 h d(-1) (0800-2000 h EST) mean concentrations of 366 and 697 microL L(-1), respectively. The two O3 treatments were charcoal-filtered air and nonfiltered air with O3 added for 12 h d(-1) to achieve seasonal 12 h d(-1) (0800-2000 h EST) mean concentrations of 23 and 72 nL L(-1), respectively. Elevated CO2 significantly stimulated growth and pod weight of Tenderette and S156, whereas elevated O3 significantly suppressed growth and pod weight of S156 but not of Tenderette. The suppressive effect of elevated O3 on pod dry weight of S156 was approximately 75% at ambient CO2 and approximately 60% at elevated CO2 (harvests combined). This amount of protection from O3 stress afforded by elevated CO2 was much less than reported for other crop species. Extreme sensitivity to O3 may be the reason elevated CO2 failed to significantly protect S156 from O3 stress.

Personal protection against mosquitoes in Dar es Salaam, Tanzania, by using a kerosene oil lamp to vaporize transfluthrin

The effectiveness of a cheap and easy method of household protection against Culex quinquefasciatus Say and other mosquitoes (Diptera: Culicidae) was investigated in Dar es Salaam, Tanzania. Kerosene-burning lamps (korobois) were modified to heat and vaporize transfluthrin, a volatile pyrethroid insecticide. When transfluthrin was added to fuel of the lamp, protection against biting was poor unless a very high concentration of insecticide was used. A modified lamp (= vaporizing koroboi) was designed to overcome this problem by mixing the insecticide with vegetable oil and heating it to 120 degrees C in a tin held just above the flame. The concentration of 0.1% transfluthrin in vegetable oil gave 50-75% reduction in biting, a similar degree of protection to that obtained from burning a mosquito coil containing a synthetic pyrethroid (0.25% d-allethrin) and significantly better protection than a locally bought coil (brand 'White Crane', probably containing DDT). Greater protection (consistently > 90%) was achieved with a higher concentration of transfluthrin (0.5%) in the vegetable oil. This modified lamp is simple, cheap and employs locally available technology. With further development, and due regard to inhalation toxicity of the vaporized materials, it may offer a more cost-effective alternative to a mosquito coil as a means of personal protection, and a useful complement to a net for the early part of the evening before bedtime.

Evaluation of Duddingtonia flagrans in reducing infective larvae of Haemonchus contortus in feces of sheep

Consequences of nematode infections due to Haemonchus contortus are a serious constraint for the sheep industry worldwide. Development of anthelmintic resistance and increasing concern about the impact of anthelmintic use dictate the need of alternative control. Such an alternative is using the nematode trapping fungus Duddingtonia flagrans to reduce infective larvae levels on pasture. Two trials were conducted to determine the effect of D. flagrans in reducing infective larvae (predominantly H. contortus) in feces. The first trial determined the dose effect of D. flagrans in reducing infective larvae in feces. Eighteen ewes were dewormed to remove existing infections and randomly assigned to six treatment groups: 5 x 10(4), 1 x 10(5), 2.5 x 10(5), 5 x 10(5), 1 x 10(6) or no (control) spores of D. flagrans per kg of body weight mixed in their feed for 7 days. Fecal samples were collected daily from these and from infected donor ewes. Feces from individual-treated ewes were mixed with equal amounts of donor ewe feces, theoretically approximating oral dose spore concentrations of 2.5 x 10(4), 5 x 10(4), 1.25 x 10(5), 2.5 x 10(5), 5 x 10(5) and no spores, and were cultured. Across dosages and during the 7 days of fungus feeding, percent reduction of infective larvae ranged from 76.6 to 100.0%. The second trial determined the effect of D. flagrans at the dose of 10(5) spores per kg body weight on reducing infective larvae in feces from naturally infected lambs. Twenty lambs were randomly assigned to either treatment or control groups based on fecal egg count. Treatment lambs were fed spores mixed in feed for 7 days. Feces were collected daily and cultured. During the 7 days of fungus feeding, the percent reduction of infective larvae ranged from 82.8 to 99.7%. Results of these trials demonstrated that the nematode trapping fungus D. flagrans was highly effective in reducing infective larvae in sheep feces and should be considered as a biological control agent for integrated nematode control programs.

Risk factors for Brucella seropositivity in goat herds in eastern and western Uganda

Cross-sectional prevalences and risk factors for Brucella seropositivity in goats in eastern and western Uganda were investigated. Serum was collected from 1518 goats randomly selected from 145 herds which had been identified using multistage sampling. The brucellosis card test (CT) and the Brucella melitensis tube-agglutination test (TAT) were used in parallel to detect antibodies against B. abortus and B. melitensis, respectively. Interviewer-administered questionnaires were used to collect information on goat health and management. This information was used in multivariable logistic-regression models to determine the risk factors for Brucella seropositivity in goat herds. For each analysis, a herd was considered positive if at least one goat in the herd tested positive for antibodies against Brucella and negative if none was positive. Four percent (55/1480) of the goats screened with the CT had antibodies against Brucella. The reactors were distributed in 13% (19/145) of the herds. The most-important herd-level risk factors identified were use of a hired caretaker as the primary manager of the operation compared to owner/family members (adjusted odds ratio (OR)=8.1; 95% CI 1.6, 39.7), keeping sheep in addition to goats (OR=6.0; CI 1.5, 23.7) compared to having no sheep, and free browsing (OR=4.7; 95% CI 1.0, 20.7) when compared to tethering or zero-grazing. Using the TAT, 10% (141/1446) of the goats tested positive. The positives were distributed in 43% (63/145) of the herds. Free browsing (OR=6.7; 95% CI 2.7, 16.9) when compared to tethering or zero-grazing and lack of veterinary care (OR=2.9; CI 1.3, 6.7) were the most-important factors identified in the multivariable model for B. melitensis herd seropositivity. To explore/reduce the risk of misclassification in a secondary analysis, herds were reclassified as positive if at least one goat tested positive on both tests and negative if none of the goats was positive on any of the two tests. Using this classification, 2% (30/1320; 95% CI 2, 3%) of the goats tested positive resulting in 13% (12/93) of the herds being positive. The distribution of the above risk factors by brucellosis herd-status (as defined by the second criterion) is also presented.

AXOR12, a novel human G protein-coupled receptor, activated by the peptide KiSS-1

A novel human G protein-coupled receptor named AXOR12, exhibiting 81% homology to the rat orphan receptor GPR54, was cloned from a human brain cDNA library. Heterologous expression of AXOR12 in mammalian cells permitted the identification of three surrogate agonist peptides, all with a common C-terminal amidated motif. High potency agonism, indicative of a cognate ligand, was evident from peptides derived from the gene KiSS-1, the expression of which prevents metastasis in melanoma cells. Quantitative reverse transcriptase-polymerase chain reaction was used to study the expression of AXOR12 and KiSS-1 in a variety of tissues. The highest levels of expression of AXOR12 mRNA were observed in brain, pituitary gland, and placenta. The highest levels of KiSS-1 gene expression were observed in placenta and brain. A polyclonal antibody raised to the C terminus of AXOR12 was generated and used to show localization of the receptor to neurons in the cerebellum, cerebral cortex, and brainstem. The biological significance of these expression patterns and the nature of the putative cognate ligand for AXOR12 are discussed.

Predictors of asthma in young children: does reporting source affect our conclusions?

Both the size and statistical significance of sociodemographic and early health risk factors on childhood asthma vary across studies, in part because some studies rely on parents' retrospective reports of health conditions while others are based on medical records. The authors compare predictors of asthma alternately using maternal reports and medical records for the same set of children. Data are from the 1988 National Maternal and Infant Health Survey and 1991 Longitudinal Follow-up, which collected information from birth certificates, medical records, and mothers of a nationally representative, population-based cohort, allowing comparison across data sources for a consistent sample of young children in the United States. Concordance between maternal reports and medical records on asthma is moderate (kappa = 0.48). The authors find considerable discrepancies in both the estimated prevalence of asthma and the distribution across children with different sociodemographic and health characteristics, depending on the source of asthma data. Black race, male gender, and preterm birth are found to be risk factors for asthma regardless of data source. Poverty, large family size, urban residence, maternal smoking, and breastfeeding are significantly associated with asthma based on maternal reports but not medical records. Lower health care utilization among poor, uninsured, and urban children may account for part of the discrepancy.

C-terminal fragments of ACTH stimulate feeding in fasted rats

Peptides derived from pro-opiomelanocortin, including alpha-MSH and ACTH, play important roles in the regulation of feeding. We investigated the central effect of ACTH 1-39 (ACTH) and peptides derived from the N-terminus (ACTH 1-10, Acetyl-ACTH 1-13-amide [alpha-MSH]) and C-terminus (ACTH 18-39 and ACTH 22-39) of this peptide on feeding in 16 hour-fasted or rats fed ad libitum. As expected, ACTH reduced feeding in fed and previously fasted rats, although this anorectic effect was more pronounced in fasted rats. The N-terminal-derived peptide alpha-MSH, but not ACTH 1-10, reduced cumulative food intake over 2 h after its injection intracerebroventricularly (icv) in 16 h-fasted, but not in fed rats. In contrast, the C-terminal fragments produced a long-lasting increase in feeding in fasted, but not in fed rats. The anorectic effects of N-terminal fragments of ACTH are recognised to be mediated via melanocortin MC4 receptors. However, the orexigenic effects of the C-terminal fragments do not appear to be conducted via MC4 receptors, since neither ACTH 18-39 nor ACTH 22-39 stimulated cAMP accumulation nor inhibited the ACTH-stimulated cAMP accumulation in HEK-293 cells transfected with the recombinant MC4 receptor.

Epidemiological observations and heterosis analysis of gastrointestinal nematode parasitism in Suffolk, Gulf Coast Native, and crossbred lambs

A crossbreeding program was conducted to evaluate the resistant status to gastrointestinal nematode parasite infection in crossbred (F1) lambs and their Suffolk and Gulf Coast Native (Native) breed counterparts. A total of 253 lambs were included in the study over 2 years. Fecal egg count (FEC) and blood packed cell volume (PCV) of 18-20 monitor lambs of each breed group in each year were collected every other week from birth to 24-30 weeks of age. The FEC and PCV of all lambs were determined at weaning (11-12 weeks of age) and at three subsequent times when anthelmintic treatment was administered. Nematode counts of wether lambs were obtained at 30 weeks of age in the first year. The epidemiological patterns of FEC and PCV of each breed group were similar in both years. The Suffolk group consistently showed the highest FEC and the lowest PCV. Conversely, the Native group had the lowest FEC and highest PCV. For the most part, all parameters for the F1 group fell intermediate to the Native and Suffolk groups. Nematode count followed the same pattern. Heterosis analysis showed that FEC, PCV, nematode count and weight gain of the F1 group favored the Native group. These results suggested that crossbreeding Suffolk to Native sheep may be a suitable way to produce lambs with improved resistance to gastrointestinal nematode infection, but production may be compromised.

Molecular characterization of the T cell repertoire using immunoscope analysis and its possible implementation in clinical practice

T lymphocytes play a central role in the pathogenesis of a large number of human conditions including autoimmunity and graft rejection. Although T cells are key players in mounting immune responses, the assessment of T cell repertoires has yet to find an important role in clinical decision making. In this review, we discuss the "immunoscope" technique and its potential diagnostic role in a variety of clinical scenarios. This is an RT-PCR based approach that subdivides a bulk T cell population (i. e. from blood, lymph, spleen, or tissue) into approximately 2800 groups based upon rearranged variable beta (Vbeta)/joining beta (Jbeta) gene segments and the resulting length of the T cell receptor's (TCR's) third complementarity determining region (CDR-3). This extensive subdivision, or focusing, allows clonal expansions to be directly observed. Such a fine-tuned analysis has revealed previously unappreciated aspects of the T cell repertoire. For instance, an antigen-specific immune response can be divided into both public and non-public components. The non-public repertoire contains the majority of the expanding T cells which are unique to the individual (private), or shared by only some (semi-private), while "public" T cells can be found responding to the antigenic determinant in every individual. Although they are often a minority of the response, the public T cell repertoire seems to play a more important role in defining, as well as driving, the overall immune phenotype in the animal. Immunoscope analysis has identified public and non-public responses in human pathologies, such as multiple sclerosis. The ability to characterize the driver T cells dictating the state of immunity/autoimmunity in individual patients will be an important step towards understanding autoimmunity and designing effective treatment for a variety of conditions including rheumatoid arthritis and multiple sclerosis. We review the current literature involving public and non-public repertoires and discuss the prospect that immunoscope analysis may play a central role in the study and perhaps the management of human autoimmune diseases, and cancer.

Anthelmintic resistance on goat farms in Georgia: efficacy of anthelmintics against gastrointestinal nematodes in two selected goat herds

Gastrointestinal nematode (GIN) parasitism is a major constraint to production of goats in the southeastern United States. The conventional method of control used by producers in this region is frequent use of anthelmintics during the warm season. Overuse of anthelmintics has led to an increase in the incidence of anthelmintic resistance in many parts of the world, but data on prevalence of anthelmintic resistance in GIN of goats in the southeastern United States are very limited. To address this issue, anthelmintic efficacy was determined in goat herds at the Fort Valley State University, Agricultural Research Station (FVSU-ARS) and the University of Georgia, College of Veterinary Medicine (UGA-CVM) using fecal egg count reduction (FECR) tests and DrenchRite((R)) larval development assays (LDA). At FVSU-ARS, 2-year-old Spanish goat does were randomly allocated to one of nine different treatment groups (n = 10): albendazole (ABZ; 20mg/kg body weight (BW)), fenbendazole (FBZ; 20mg/kg BW), ivermectin (IVM; 0.4 mg/kg BW), doramectin (DRM; 0.4 mg/kg BW), moxidectin (MOX; 0.4 mg/kg BW), levamisole (LEV; 12 mg/kg BW), morantel tartrate (MOR; 10mg/kg BW), a combination of IVM (0.4 mg/kg BW) and ABZ (20 mg/kg BW), and untreated controls. At UGA-CVM, goats were randomly allocated to one of five different treatment groups (n = 8): ABZ (20 mg/kg BW), IVM (0.4 mg/kg BW), MOX (0.4 mg/kg BW), LEV (12 mg/kg BW), and untreated controls. All drugs in both experiments were administered orally. Anthelmintic efficacy was calculated by comparing 14-day post-treatment FEC of treated and control animals, and percent reductions were interpreted using the World Association for the Advancement of Veterinary Parasitology guidelines for resistance. For the LDA, nematode eggs were isolated from pooled fecal samples of untreated control goats in each herd and used to perform DrenchRite((R)) assays. In the FVSU-ARS herd, MOX, LEV, the combination of IVM and ABZ, IVM, DRM, ABZ, MOR, and FBZ reduced FEC by 100, 91, 88, 78, 76, 62, 48, and 10%, respectively. In the UGA-CVM herd, MOX, LEV, ABZ and IVM, reduced FEC by 100, 94, 87, and 0%, respectively. In both herds moxidectin was the only drug tested that was fully effective. Results of the LDA were in agreement with results of the FECR tests for both herds. These data demonstrate the presence of GINs resistant to all three major anthelmintic classes in both goat herds.

The effect of intracytoplasmic sperm injection and semen parameters on blastocyst development in vitro

The present study compares the development and quality of blastocysts derived from conventional oocyte insemination with those derived from intracytoplasmic sperm injection (ICSI). Oocytes were collected from patients undergoing ovarian stimulation with human menopausal gonadotrophins for IVF. Patients with normal semen were assigned to conventional oocyte insemination while those with progressive motility <20% and/or normal sperm morphology < or =4% were assigned to ICSI. Resulting embryos were cultured for up to 6 days. The mean number and percentage of embryos reaching the blastocyst stage and the mean number and percentage of blastocysts of high quality on days 5-6 were assessed for both treatment groups and compared. The influence of paternal factors (sperm concentration, motility, progressive motility, morphology) on blastocyst development and quality were assessed by regression analyses. Significantly more ICSI-derived embryos arrested at the 5- to 8-cell stage (P = 0.024) concomitant with the activation of the paternal genome than those derived from conventional oocyte insemination. Significantly fewer ICSI-derived embryos reached the blastocyst stage on days 5-6 (P<0.001) and significantly fewer ICSI-derived embryos were of high quality (P = 0.002) compared with conventional oocyte insemination. When treatment groups were combined and evaluated by regression analysis, progressive motility and sperm morphology were significantly correlated with diminished blastocyst development and quality (P < 0.05). From these data, we conclude that paternal factors and/or performing ICSI in cases of severe male factor infertility may have a detrimental effect on blastocyst development and their quality.

Racial differences in colorectal cancer mortality. The importance of stage and socioeconomic status

This investigation studies racial and socioeconomic differences in mortality from colorectal cancer, and how they vary by stage and age at diagnosis. Cox proportional hazards models were used to estimate the hazard ratio of dying from colorectal cancer, controlling for tumor characteristics and sociodemographic factors. Black adults had a greater risk of death from colorectal cancer, especially in early stages. The gender gap in mortality is wider among blacks than whites. Differences in tumor characteristics and socioeconomic factors each accounted for approximately one third of the excess risk of death among blacks. Effects of socioeconomic factors and race varied significantly by age. Higher stage-specific mortality rates and more advanced stage at diagnosis both contribute to the higher case-fatality rates from colorectal cancer among black adults, only some of which is due to socioeconomic differences. Socioeconomic and racial factors have their most significant effects in different age groups.

Early childhood chronic illness: comparability of maternal reports and medical records

OBJECTIVES

The research reported here seeks to quantitatively assess the comparability of two widely used sources of information on child health: maternal reports and medical records. The analysis provides a comparison of how well maternal reports and medical provider data agree on 15 types of chronic health conditions, ranging from specific illnesses such as asthma or sickle cell anemia to broader categories such as chronic heart or orthopedic conditions, to impairments such as vision, hearing, or speech problems.

METHODS

This study uses data on a nationally representative sample of 6201 preschool aged children whose mothers participated in the 1991 Longitudinal Followup (LF) to the 1988 National Maternal and Infant Health Survey (NMIHS) and whose identified health care providers supplied medical visit data for the children. The LF and NMIHS were conducted by the National Center for Health Statistics (NCHS), Centers for Disease Control and Prevention (CDC), in collaboration with a number of other agencies of the Federal Government. In the 1991 LF survey, the mothers' questionnaire included questions on chronic and acute health conditions, accidents requiring medical attention, and hospital admissions for their children that had been included in the 1988 NMIHS. The mothers were also asked to grant NCHS permission to request medical records from the children's medical providers.

RESULTS

Kappa statistics reveal poor agreement for 12 of 15 conditions studied. Weighted prevalence estimates vary widely across sources. For some conditions, despite apparently similar prevalence estimates from the two sources, mothers' reports and medical records identified very different groups of children as "cases." Concurrence rates were lower for children from poor, less educated, and Hispanic families. Reasons for and implications of these findings are also discussed.

Attempts to control haemonchosis in grazing ewes by vaccination with gut membrane proteins of the parasite

A vaccination trial was conducted to evaluate the potential benefit of Haemonchus contortus gut membrane proteins as vaccine antigens under field conditions in Louisiana. The trial was conducted in the summer of 1996 in a flock of ewes grazing pasture naturally infected with H. contortus. Ewes were randomly assigned to three treatment groups (vaccine, adjuvant only, and saline) and fecal egg counts (FEC, measured as eggs per gram of feces), packed cell volumes (PCV), and antibody levels were monitored fortnightly for 12 weeks. It was shown by FEC that there were large individual variations in susceptibility to H. contortus in both vaccinated and non-vaccinated sheep, a finding which could have masked differences between treatments when analyzed by conventional statistical methods. Based on their egg counts before the period when the vaccination could have had an effect, all ewes were categorized as 'susceptible' or 'relatively resistant'. The significance of differences between FEC, PCV and antibody responses of vaccinated and control sheep were tested separately for the 'susceptible' and 'relatively resistant' category. The 'susceptible' vaccinates shed 65% fewer worm eggs during the period when the vaccine could have had an effect, but the difference was only significant on Week 6 post-vaccination. In these experiments, it was difficult to completely exclude the confounding effect of having 'relatively resistant' sheep in the control group. More studies are needed to further evaluate H11 and H-gal-GP antigens under field conditions.

Differences in AIDS knowledge among Spanish and English speakers by socioeconomic status and ability to speak English

Previous studies have shown that Hispanics know less about acquired immunodeficiency syndrome (AIDS) than non-Hispanics, but few studies have examined the role of language or socioeconomic status. We used data from a 1998 population-based sample survey of New Jersey adults to compare levels of AIDS knowledge among English and Spanish speakers, taking into account educational attainment and ability to speak English. Spanish speakers, especially those who filled out the questionnaire in Spanish, knew less about AIDS transmission, although their general AIDS knowledge was comparable to English speakers with similar educational attainment. Differences between Hispanics who speak primarily English and those who speak primarily Spanish underscore the idea that linguistic and cultural barriers vary within a cultural group and should be taken into account in the design of AIDS education programs.

Intrauterine cytomegalovirus infection and glycoprotein B genotypes

Cytomegalovirus (CMV) strains display polymorphisms for the gene encoding glycoprotein B (gB; gpUL55). Recent data suggest that the gB genotype may influence the outcome of acquired CMV infections. To determine whether the gB genotype also contributes to the outcome of intrauterine infection, CMV strains were studied from 56 infants with culture-confirmed intrauterine CMV infections who were born in Iowa or Texas. CMV gB genotypes were compared with the neonatal clinical features and neurodevelopmental outcomes. Fifty-three strains (95%) could be assigned a gB genotype. The overall distribution of genotypes was as follows: type 1, 50%; type 2, 18%; type 3, 23%; and type 4, 4%. Strains with the gB 3 genotype were more common among the Iowa infants (P=.082). The gB 3 genotype was more common among infants with asymptomatic infections (P=.004), but geographic location and ascertainment biases may have accounted for these differences. The gB genotypes did not correlate with the neurodevelopmental outcome of intrauterine infection.

Influence of foot, leg and shoe characteristics on subjective comfort

The purpose of this study was to determine the relationships between foot and leg characteristics, shoe characteristics, and the short-term subjective comfort of three different pairs of athletic shoes. Static measurements of foot dimension and leg angles were taken from eighteen subjects. Subjects rated the comfort of three different athletic shoes for standing, walking and running. The shoes were quantified by internal dimensions, hardness, flexibility and torsional stiffness. Average comfort ratings decreased from standing to walking to running. One shoe seemed suited for only a small group of subjects. In contrast, another shoe was generally comfortable for a large group. Skeletal alignment, specifically eversion angle, was related to comfort for one shoe. Therefore, fit of the shoe is not sufficient for comfort. Skeletal alignment, shoe torsional stiffness and cushioning seem to be mechanical variables which may be important for comfort.

Neuromedin U is a potent agonist at the orphan G protein-coupled receptor FM3

Neuromedins are a family of peptides best known for their contractile activity on smooth muscle preparations. The biological mechanism of action of neuromedin U remains unknown, despite the fact that the peptide was first isolated in 1985. Here we show that neuromedin U potently activates the orphan G protein-coupled receptor FM3, with subnanomolar potency, when FM3 is transiently expressed in human HEK-293 cells. Neuromedins B, C, K, and N are all inactive at this receptor. Quantitative reverse transcriptase-polymerase chain reaction analysis of neuromedin U expression in a range of human tissues showed that the peptide is highly expressed in the intestine, pituitary, and bone marrow, with lower levels of expression seen in stomach, adipose tissue, lymphocytes, spleen, and the cortex. Similar analysis of FM3 expression showed that the receptor is widely expressed in human tissue with highest levels seen in adipose tissue, intestine, spleen, and lymphocytes, suggesting that neuromedin U may have a wide range of presently undetermined physiological effects. The discovery that neuromedin U is an endogenous agonist for FM3 will significantly aid the study of the full physiological role of this peptide.

A survey of GP views in intra-uterine contraception

AIMS

To investigate knowledge and attitudes towards intra-uterine contraception.

DESIGN

Anonymous postal survey of 441 GPs (153 female and 288 male GPs) from the FHSA register in Stockport and Manchester.

SETTING

General practices in Stockport and Manchester. Main outcome measure. Response to a series of questions concerning attitudes and knowledge of intra-uterine contraception.

RESULTS

One hundred and forty-two responses were received, giving a 35% response rate. Thirty-four percent of responding GPs did not fit intra-uterine devices (IUDs), with only 10% fitting more than 30 a year. There was a significant trend against IUD fitting by male GPs and GPs aged <40 years. Younger GPs with <10 years experience were significantly more aware of the reliability of intra-uterine contraception, but perceived IUD fitting as inconvenient for both the patient and the doctor. Female GPs had better knowledge and more positive attitudes to IUDs than male GPs.

CONCLUSION

GPs may have difficulties in maintaining expertise. Primary care groups may opt to concentrate fittings in a few expert practices, or refer women to centrally based family planning clinics for IUD fitting.

Differences in susceptibility to gastrointestinal nematode infection between Angus and Brangus cattle in south Louisiana

Breed susceptibility to nematode infection was evaluated in Angus (Bos taurus) and Brangus (B. indicus crossbreed) cattle. A cow-calf herd and a yearling replacement heifer herd were monitored during one grazing season. Calves were born in March and were weaned in October. Individual rectal fecal samples were collected monthly from the two herds and processed for fecal egg counts (FEC) and coprocultures. Cow and calf FEC increased from April, reaching maximum values during the summer. Angus cows and calves had significantly (p<0.05) greater FEC than Brangus cows and calves, and Haemonchus and Cooperia were the predominant genera. Replacement heifer FEC showed a similar pattern with maximum levels during late summer/fall, and Haemonchus was the predominant genus. No significant differences were seen between breeds, however, infection levels were consistently lower in Brangus heifers. Ostertagia was present in cows and heifers only in fall/winter, which is consistent with summer inhibition. The data suggested that cows were an important source of pasture contamination for their susceptible calves and that the Brangus breed was relatively more resistant to infection. The use of B. indicus crossbreeds may help in alleviating reliance on chemical control by reducing the rate of pasture contamination and subsequent infection losses.

The effects of race/ethnicity and income on early childhood asthma prevalence and health care use

OBJECTIVES

Asthma is the most common chronic illness among US children and is most prevalent in low-income and minority groups. We used multivariate models to disentangle the effects of race/ethnicity, income, and other individual-level risk factors on asthma in a population-based sample of children aged 3 years.

METHODS

Data are from the 1988 National Maternal and Infant Health Survey and 1991 Longitudinal Follow-Up. Odds ratios of asthma prevalence, hospitalization, and emergency room use were estimated, with control for socioeconomic characteristics, health behaviors, and insurance.

RESULTS

Asthma prevalence, hospitalization, and emergency room use declined with increasing income for non-Black but not Black children.

CONCLUSIONS

Lifetime income and sociodemographic characteristics do not explain the excess risks of asthma and emergency health care use for asthma among young Black children.

Efficacy of moxidectin 0.5% pour-on against swine nematodes

Forty pigs with induced infections of Ascaris suum, Trichuris suis, Metastrongylus spp., Oesophagostomum dentatum and O. quadrispinulatum were assigned to five-dose groups of moxidectin 0.5% pour-on with eight pigs per dose group. The doses were: moxidectin, 0 (vehicle control), 0.75, 1.00, 1.25, and 1.50 mg/kg(-1) body weight. Worm egg counts (EPG) were made from fecal samples collected on Day 2 pretreatment and on Day 14 or 15 post-treatment. Animals were ranked according to the descending order of A. suum egg counts made on Day 2 and blocked in groups of five. Pigs in blocked groups were assigned randomly to each of the five dose groups. Treatment doses were calculated on the basis of weights taken on Day 1 and were administered topically from the neck to the base of the tail. Pigs were housed by pairs in individual pens provided with self-feeders and automatic waterers. Necropsies were performed on equal numbers of pigs from each treatment group on days 14 and 15 post-treatment. Adult and larval worms were collected, identified and counted by standard parasitological techniques. All counts were transformed by Y=log10 (count+1) transformation prior to analysis. A two-way analysis of variance was conducted and treatment effect was tested for significance at the 5% level. Efficacies based on geometric means and optimal doses were as follows: Ascaris suum, 98.3% at 1.25; Metastrongylus spp., 100% at 0.75; Oesophagostomum quadrispinulatum, 100% at 1.50; and Trichuris suis, 93.5% at 0.75. Efficacy for O. dentatum was from 81.3% to 100%; however, the average number of O. dentatum (30) was too small for significance. Two species of lungworms were present, Metastrongylus apri and M. pudendotectus but they were not speciated at necropsy. As reported for several anthelmintics, the efficacy of moxidectin was variable for Trichuris. The highest efficacy was in the 0.75 dose group with six pigs harboring a few or no worms. The lowest efficacy was in the 1.25 group with only two pigs harboring a few or no worms.

An automated semiquantitative B and T cell clonality assay

BACKGROUND

Rearrangements of the antigen receptor genes in B and T cells generate products of unique length and sequence. Polymerase chain reaction (PCR) assays are routinely used to identify clonal lymphocyte populations by detecting clonal V-J rearrangements or chromosomal translocations within these antigen receptor loci. Multiple primer sets are, however, required to detect the majority of clonal B- and T-cell malignancies. Products from the individual reactions must be analyzed separately to avoid misinterpretation. Moreover, small clonal populations remain difficult to identify. To address these difficulties, we propose that an integrated fluorescence-based approach to clonal B- and T-cell detection would simultaneously identify both B- and T-cell neoplasia; increase amplicon resolution, analytic sensitivity, and assay throughput; produce more comprehensive and semiquantitative data useful for evaluation of hematologic malignancies; and eliminate labor intensive agarose and polyacrylamide gel electrophoresis.

METHODS AND RESULTS

Samples were genomic DNA and cDNA. Differentially labeled primers were used to amplify regions diagnostic for B- and T-cell clonality in a single plate with a single thermocycler program. Combined amplicon products underwent capillary electrophoresis for high resolution fractionation and differential fluorescence detection and quantification. Data were automatically analyzed and archived. In a comparative analysis of a variety of clinical samples, this automated and integrated B- and T-cell assay showed >94% agreement (33 of 35 results) with individual B- and T-cell PCR assays. Furthermore, this assay had an overall monoclonality detection rate of 100%, and as little as 100 ng of sample DNA yielded complete B- and T-cell clonality test results. The limit of detection was approximately 10-2 cells, and amplicons were sized to within 0.1 basepair. Serial dilutions of clonal B- and T-cell lines comprising a coded proficiency panel were identified and correctly ranked. Specificity was 100% as determined by analysis of 18 control samples that were all negative for B- and T-cell clonality.

CONCLUSIONS

Our data show that this automated and integrated B- and T-cell clonality assay system is a sensitive and specific tool useful for rapid identification of clonal lymphocyte populations and will likely have broad clinical applications.

A new strategy for treating nets. Part 2: users' perceptions of efficacy and washing practices and their implications for insecticide dosage

The conventional way to treat a mosquito net with pyrethroid insecticide is to apply a standard dosage every 6-12 months, and to avoid washing the net until just before retreatment. In some places, nets are normally washed much more often than this, and it may then be more appropriate to apply smaller amounts of insecticide after each wash. The choice of strategy must take into account not only biological effectiveness, but also users' perceptions of this effectiveness and their net-washing habits. We used focus groups to compare users' responses to nets treated with different dosages and chemicals. One hundred current net users in urban Dares-Salaam were each given a net that had been pretreated either with permethrin (200 or 500 mg/m2), or with lambdacyhalothrin (3 or 15 mg/m2), or with water. Neither participants nor investigators knew which group had received which treatment. Focus group discussions were held after 2, 8 and 12 weeks. Participants greatly preferred treated nets. Low doses were perceived to be less effective, especially after 8 and 12 weeks. After 12 weeks most participants had washed their nets, despite requests to the contrary Dirty nets were regarded as unhealthy and socially unacceptable. Few participants experienced side-effects or expressed fears about the safety of treatment. We conclude that asking people to refrain from washing their nets is unrealistic. A 'low-dose frequent-treatment' strategy of insecticide application may be more appropriate in the long run. At first, however, low doses give perceptibly inferior protection. An initial high (loading) dose, followed by frequent lower (maintenance) dosages, might solve this problem.

A new strategy for treating nets. Part 1: formulation and dosage

The conventional dosages of pyrethroid insecticides on mosquito nets assume that nets will be retreated at 6-12 month intervals. However, dosage should be related to washing of nets; if nets are only washed once or twice a year, their dosage requirements will be different to those which are washed fortnightly. A 'low-dose, frequent-wash' retreatment system might be technically more appropriate and more affordable where nets are washed frequently, as they are in Dar es Salaam. Moreover, for use as a domestic insecticide, water-based formulations of pyrethroid are preferable to the more commonly used emulsifiable concentrates (ECs). This paper reports laboratory evaluations of three formulations (ECs, Flowable, CS) of three pyrethroids (deltamethrin, lambdacyhalothrin, permethrin). Insecticidal activity was tested using serial bioassays at a range of dosages using Anopheles gambiae. The water-based formulations were no less effective than the ECs, even at the lowest dosages. Nets treated with 3 mg/m2 and then repeatedly washed and retreated after each wash with either 3 mg/m2 or 1 mg/m2 were subjected to gas chromatography analysis. This showed that the amounts of pyrethroid in the nets accumulated rapidly over the first few wash-retreatment cycles and then remained fairly stable over subsequent cycles. These nets gave consistently high bioassay mortalities throughout the experiment, while the mortality declined rapidly after several washes with the nets that were treated at 3 mg/m2 but not retreated. Experimental huts were used to compare the effectiveness of these 2 net retreatment regimes and nets which were not retreated. All nets caused high mortality rates amongst Anopheles females, but had negligible effects on culicines; either in killing them or in preventing feeding. Therefore use of a high 'loading' dose for initial treatment with lower 'maintenance' doses for retreatment may be preferable to ensure that net users promptly perceive the benefits of the insecticide against culicines.

Notification of real-time clinical alerts generated by pharmacy expert systems

We developed and implemented a strategy for notifying clinical pharmacists of alerts generated in real-time by two pharmacy expert systems: one for drug dosing and the other for adverse drug event prevention. Display pagers were selected as the preferred notification method and a concise, yet readable, format for displaying alert data was developed. This combination of real-time alert generation and notification via display pagers was shown to be efficient and effective in a 30-day trial.

Urinary bombesin-like peptide levels in infants and children with bronchopulmonary dysplasia and cystic fibrosis

Compared to normal infants and children, there are increased numbers of neuroendocrine cells with bombesin-like peptide (BLP) immunostaining in the lungs of infants and children with bronchopulmonary dysplasia (BPD) and cystic fibrosis (CF). However, there are no data documenting levels of urinary BLP in normal infants and children, or in children with lung disease. We therefore determined the normal developmental pattern for urinary BLP excretion in healthy infants and children, and in infants and children with BPD and CF, and correlated these findings with the subjects' clinical course. We measured urinary BLP levels in 110 subjects: 54 controls, 33 with BPD, and 23 with CF. An age-dependent decline in urinary bombesin levels was evident in the control and BPD subjects, but not in those with CF. There were no statistically significant differences in BLP levels between normal infants and those with BPD. Mean BLP levels were higher in the more immature preterm infants with BPD who required increased ventilatory support. The highest mean BLP levels were documented in BPD infants under age 3 months (882 fmol/mg creatinine), in controls between 3 and 12 months of age (625 fmol/mg creatinine), and in 12-60-month-old CF subjects (486 fmol/mg creatinine). Thus there is an age-dependent decline in BLP levels in controls and BPD, but not in CF. We speculate that the elevated urinary BLP levels in infants and children with BPD and CF may reflect increased pulmonary neuroendocrine cell activity in these conditions, due to the epithelial regenerative response to airway damage and repair.

Can anything be done to maintain the effectiveness of pyrethroid-impregnated bednets against malaria vectors?

Pyrethroid-treated bednets are the most promising available method of controlling malaria in the tropical world. Every effort should be made to find methods of responding to, or preventing, the emergence of pyrethroid resistance in the Anopheles vectors. Some cases of such resistance are known, notably in An. gambiae in West Africa where the kdr type of resistance has been selected, probably because of the use of pyrethroids on cotton. Because pyrethroids are irritant to mosquitoes, laboratory studies on the impact of, and selection for, resistance need to be conducted with free-flying mosquitoes in conditions that are as realistic as possible. Such studies are beginning to suggest that, although there is cross-resistance to all pyrethroids, some treatments are less likely to select for resistance than others are. Organophosphate, carbamate and phenyl pyrazole insecticides have been tested as alternative treatments for nets or curtains. Attempts have been made to mix an insect growth regulator and a pyrethroid on netting to sterilize pyrethroid-resistant mosquitoes that are not killed after contact with the netting. There seems to be no easy solution to the problem of pyrethroid resistance management, but further research is urgently needed.

A comparative study of in vivo mutation assays: analysis of hprt, lacI, cII/cI and as mutational targets for N-nitroso-N-methylurea and benzo[a]pyrene in Big Blue mice

We have compared the response of the native hprt gene and the lacI, cII, and cI transgenes in Big Blue B6C3F1 mice following treatment with either N-nitroso-N-methylurea (MNU) or benzo[a]pyrene (BaP). Three weeks after mutagen treatment splenic T cells were isolated from the animals, and samples were either cultured to measure mutation at the native hprt locus or used to extract genomic DNA for transgene mutation analysis. Phage rescued from extracted DNA were plated in the presence of 5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside (X-gal) to score lacI mutations, or plated on a hflAB lawn to score cII and cI mutants. With MNU hprt mutant frequency increased in a dose-related, sublinear manner up to 78-fold above background at the highest dose tested (20 mg/kg). In comparison, the lacI transgene yielded only a 3.1-fold increase at this dose, and the cII and cI transgenes did not show any increase. With 150 mg/kg BaP a 5.8- and 8.7-fold increase in mutant frequency was observed at hprt and lacI, respectively, while only a 1.3-fold increase was observed at cII. DNA sequencing revealed an increase in GC-->TA transversions among the cII mutants, suggesting that the increase was related to BaP exposure. No significant increase in cI mutant frequency was observed. Therefore, the order of mutation assay sensitivity was hprt>lacI>cII/cI with MNU, and hprt approximately lacI> cII/cI with BaP. While the hflAB selection system offers significant advantages with respect to cost and effort when compared to the lacI assay, additional evaluation of its sensitivity is warranted.

Biliary pancreatitis: the era of laparoscopic cholecystectomy

OBJECTIVE

To evaluate the efficacy and safety of a combined approach to the treatment of biliary pancreatitis using laparoscopic cholecystectomy and selective endoscopic retrograde cholangiopancreatography (ERCP).

DESIGN

Consecutive case series.

SETTING

Tertiary care center.

PATIENTS

All patients undergoing primary operations for biliary pancreatitis during 2 time periods were included. In the open era (June 1982 through May 1988), there were 276 patients; in the laparoscopic era (January 1996 through June 1997), there were 114 patients.

INTERVENTIONS

Open cholecystectomy with or without common bile duct exploration (CBDE); laparoscopic cholecystectomy with selective ERCP and/or laparoscopic CBDE.

MAIN OUTCOME MEASURES

Two periods were compared for morbidity, mortality, the duration of preoperative and postoperative stays, and the total length of hospitalization.

RESULTS

Both groups were demographically similar and had the same mortality (1.9%). Laparoscopic cholecystectomies provided a preoperative stay comparable to open cholecystectomy (6.4 vs 5.8 days), a shorter postoperative stay (1.5 vs 8.5 days), a lower incidence of CBDE (6.6% vs 26%), and a lower morbidity (8% vs 13.7%). The addition of an ERCP to laparoscopic cholecystectomy was associated with prolongation of the preoperative stay (7.4 vs 5.0 days), a comparable postoperative stay, a lower conversion rate (7.5% vs 13%), and fewer CBDEs (3% vs 13%). In 27 (42%) of the 64 ERCP cases, no stones were found.

CONCLUSIONS

Treatment of biliary pancreatitis with combined laparoscopic cholecystectomy and selective ERCP is safe and effective and is associated with a shorter hospitalization and fewer CBDEs than open cholecystectomy. Unnecessary ERCPs can be reduced by improved selection criteria or greater dependence on operative CBDE.

Serum paraoxonase (PON1) 55 and 192 polymorphism and paraoxonase activity and concentration in non-insulin dependent diabetes mellitus

Human serum paraoxonase (PON1) is located on high density lipoprotein and has been implicated in the detoxification of organophosphates and possibly in the prevention of low density lipoprotein lipid peroxidation. PON1 has two genetic polymorphisms both due to amino acid substitution, one involving glutamine (A genotype) and arginine (B genotype) at position 192 and the other leucine (L genotype) and methionine (M genotype) at position 55. We investigated the effect of these polymorphisms on serum PON1 activity and concentration in 252 non-insulin dependent diabetes mellitus (NIDDM) individuals and 282 non-diabetic controls. Serum PON1 activity in the controls (214.6 nmol/min per ml (26.3-620.8)) was significantly higher than in NIDDM (158.7 nmol/min per ml (3.6-550.5) (P < 0.001) as was serum PON1 concentration (89.1 microg/ml (16.8-527.4)) compared to 76.7 microg/ml (3.6-443.8) (P < 0.01). In the control population MM homozygotes had significantly lower serum PON1 activity regardless of the 192 polymorphism whereas in NIDDM both LM and MM genotypes had lower serum PON1 activity than LL homozygotes only when the 192 AA genotype was present. Serum PON1 concentration was lower in NIDDM with AA/LM, AA/LL, AB/LL and AB/MM genotypes than in controls. Differences in PON1 activity were the major cause of differences in specific activity between genotypes. Neither the PON1 55 or 192 polymorphisms consistently influenced the serum lipid or lipoprotein concentrations in either population. Low serum PON1 activity in NIDDM may be related to an increased tendency to lipid peroxidation and may also increase susceptibility to toxicity from organophosphate exposure. Our findings thus raise the possibility that PON1 may be of importance in both the genetic and acquired predisposition to premature atherosclerosis and neuropathy in diabetes.

DNA synthesis inhibition as an indirect mechanism of chromosome aberrations: comparison of DNA-reactive and non-DNA-reactive clastogens

Positive results in the in vitro assay for chromosome aberrations sometimes occur with test chemicals that apparently do not react with DNA, being negative in tests for mutation in bacteria, for DNA strand breaks, and for covalent binding to DNA. These chromosome aberrations typically occur over a narrow concentration range at toxic doses, and with mitotic inhibition. Indirect mechanisms, including oxidative damage, cytotoxicity and inhibition of DNA synthesis induced by chemical exposure, may be involved. Understanding when such mechanisms are operating is important in evaluating potential mutagenic hazards, since the effects may occur only above a certain threshold dose. Here, we used two-parameter flow cytometry to assess DNA synthesis inhibition (uptake of bromodeoxyuridine [BrdUrd]) associated with the induction of aberrations in CHO cells by DNA-reactive and non-reactive chemicals, and to follow cell cycle progression. Aphidicolin (APC), a DNA polymerase inhibitor, induces aberrations without reacting with DNA; 50 microM APC suppressed BrdUrd uptake during a 3-h treatment to <10% of control levels. Several new drug candidates induced aberrations concomitant with marked reductions in cell counts at 20 h (to 50-60% of controls) and suppression of BrdUrd uptake (<15% of control). Several non-mutagenic chemicals and a metabolic poison, which induce DNA double strand breaks and chromosome aberrations at toxic dose levels, also suppressed DNA synthesis. In contrast, the alkylating agents 4-nitroquinoline-1-oxide, mitomycin C, methylnitrosourea, ethylnitrosourea, methylmethane sulfonate and ethylmethane sulfonate, and a topoisomerase II inhibitor, etoposide, produced many aberrations at concentrations that were less toxic (cell counts >/=73% of controls) and gave little inhibition of DNA synthesis during treatment (BrdUrd uptake >/=85% of controls), although cell cycle delay was seen following the 3-h treatment. Thus, inhibition of DNA synthesis at the time of treatment is supporting evidence for an indirect mechanism of aberrations, when there is no direct DNA reactivity.

Developmental screening scores among preschool-aged children: the roles of poverty and child health

OBJECTIVES

To investigate, using a nationally representative sample of preschool-aged children, the relationship among poverty history, child health, and risk of an abnormal developmental screening score.

METHODS

Data were derived from the 1988 National Maternal and Infant Health Survey and 1991 Longitudinal Follow-up. Family income in the child's prenatal year and at 2 years old defined a poverty history for each child. Multivariate logistic regression was used to estimate the effects of poverty history on risk of an abnormal screening score or delays in large-motor, personal-social, or language subscales.

RESULTS

Poor and near-poor children were 1.6 to 2.0 times as likely as nonpoor children to be classified as abnormal, even when maternal and household characteristics and the child's health history were taken into account. Preterm birth, chronic illness, dearth of reading materials in the home, and maternal depression were also associated with elevated risks of abnormal scores.

CONCLUSIONS

Poverty is the largest single predictor of an abnormal developmental screening score. The implications of inadequate medical care among poor children for the interpretation of individual screening scores and for amelioration of problems are also discussed.

Biomedical risk factors for hospital admission in older adults

OBJECTIVES

This study examines the influence of risk factors such as cigarette smoking, blood pressure, serum cholesterol, or chronic illness on frequency of hospital admission in a population-based sample.

METHODS

Data from the National Health and Nutrition Examination Survey I Epidemiologic Followup Study for 6,461 adults aged 45 years and older were used to assess the influence of risk factors measured by interview, physical examination, and laboratory tests on frequency of hospital admission over a 12- to 16-year follow-up period. Cox proportional hazard regressions were estimated separately for men and women and for ages 45 to 64 years and 65 years and older. SUDAAN software was used to correct for clustering, stratification, unequal weighting, and multiple observations per respondent.

RESULTS

Risk of hospitalization was higher for current but not former smokers (relative risk [RR] = 1.17-1.34 for different age-sex groups; P < 0.01), higher blood pressure (RR = 1.25-1.28 for ages 45-64; RR = 1.07-1.15 for ages 65 and older; P < 0.01), and lower serum albumin (RR = 1.08-1.14; P < 0.01). Diabetes, lung conditions, heart attack, and ulcer each were associated with higher risk in at least three of the four age-sex groups, as was arthritis among the middle-aged (45-64 years). Serum cholesterol was not associated with hospitalization.

CONCLUSIONS

Chronic conditions with high morbidity as well as many factors associated with mortality are associated with a higher frequency of hospitalization.

Comparison of motility and membrane integrity to assess rat sperm viability

Rat sperm motility and membrane integrity were compared as endpoints for viability. Sperm motility was measured by computer-assisted semen analysis (CASA), whereas membrane integrity was assessed by flow cytometric analysis of sperm stained with two nucleic acid stains, SYBR-14 and propidium iodide. The two techniques were compared in experiments that examined sperm viability over time and by analysis of known mixtures of control and freeze/thaw-killed sperm. Results from the two approaches were quantitatively very similar. Sperm from rats treated with dibromoacetic acid (600 or 1200 mg/kg) or alpha-chlorhyrin (100 mg/kg) were also analyzed. Neither technique detected a treatment-related effect with dibromoacetic acid. CASA identified a significant decrease in sperm motility in alpha-chlorhyrin-treated rats, whereas flow cytometric analysis did not find a measureable change in sperm membrane integrity. Because decreases in sperm motility would be expected to directly affect fertility, CASA may be a more robust endpoint for risk assessment in reproductive toxicology studies than flow cytometric analysis of membrane integrity.

Epidemiology of gastrointestinal nematode parasitism in Suffolk and Gulf Coast Native sheep with special emphasis on relative susceptibility to Haemonchus contortus infection

An eight-year study was conducted to define the epidemiology of gastrointestinal nematode infection in Suffolk and Gulf Coast Native (Native) breeds of sheep, and to determine if the Native sheep is more resistant to infection. For the initial three years, each breed grazed separate pastures where anthelmintic treatments were administered to individual animals on a salvage basis. For the last five years, both breeds grazed concurrently; anthelmintic treatments were administered to individual animals on a salvage basis for the first three years, and to all animals, when treatment criteria were met, for the last two years. The fecal egg count (FEC) and blood packed cell volume (PCV) were monitored, and tracer lamb nematode burdens were determined. Overall, FEC for both breeds increased in the spring (periparturient rise) for most years and in the summer for all years. Under separate grazing conditions, Native ewes and lambs had consistently lower infection levels than Suffolk ewes and lambs. During the haemonchosis season (June-September) each year, Suffolk ewe and lamb PCV decreased, and Native ewe and lamb PCV remained relatively stable. The salvage treatment protocol resulted in 27 treatments for Suffolk and one for Native ewes; similarly for lambs, 13 for Suffolk and zero for Native. Tracer lambs grazed with their respective breed, and the FEC and mean total nematode burden corresponded with the pattern of infection for their respective breed. The predominant nematodes found in Suffolk and Native tracer lambs were Haemonchus contortus and Trichostrongylus spp., respectively. Under concurrent grazing conditions, the same seasonal repeatable pattern of infection was present and was exhibited by both breeds, with the Native ewes and lambs being consistently and significantly (p < or = 0.05) lower for FEC and higher for PCV. The salvage treatment protocol resulted in 57 and zero treatments for Suffolk and Native ewes, respectively; for lambs, 46 and 11. Tracer lamb nematode burdens again corresponded to their respective breed pattern of infection, with H. contortus and Trichostrongylus spp. being predominant in Suffolk and Native lambs, respectively. Data from all tracer lambs showed a relatively low level of hypobiosis (H. contortus only), and, although there was no consistent hypobiosis season, the tendency was for a higher level to occur in the fall. These results showed that the classic repeatable seasonal pattern of gastrointestinal nematode infection occurred in both breeds of sheep, and that Native sheep were more resistant to infection (specifically H. contortus) than Suffolk sheep.

Bladder petechiae after cystoscopy and hydrodistension in men diagnosed with prostate pain

PURPOSE

We determined if men with prostate pain syndromes have petechiae in the bladder after hydrodistension.

MATERIALS AND METHODS

A total of 60 men with the diagnosis of prostate pain and without bacteriuria underwent cystoscopy and hydrodistension under a general or regional anesthetic.

RESULTS

Of the 60 men 35 (58%) had moderate to severe petechiae similar in appearance to women with interstitial cystitis after hydrodistension. Men with moderate to severe bladder petechiae had fewer leukocytes in expressed prostatic secretions, smaller bladder capacities and less often testicular pain than men with more normal appearing bladders after hydrodistension. Symptomatic improvement 2 to 6 weeks after hydrodistension was more common in men with moderate to severe petechiae than in those with fewer petechiae. Absence of rectal pain predicted symptomatic improvement after hydrodistension.

CONCLUSIONS

We suggest that bladder petechiae, and possibly interstitial cystitis or a related condition, may be more frequently associated with prostate pain syndromes in men than previously appreciated.

Cell-specific regulation of expression of plasma-type platelet-activating factor acetylhydrolase in the liver

Platelet-activating factor (PAF) is a potent proinflammatory phospholipid mediator that causes hypotension, increases vascular permeability, and has been implicated in anaphylaxis, septic shock and several other inflammatory responses. PAF is hydrolyzed and inactivated by the enzyme PAF-acetylhydrolase. In the intact rat, a mesenteric vein infusion of lipopolysaccharide (LPS) served as an acute, liver-focused model of endotoxemia. Plasma PAF-acetylhydrolase activity increased 2-fold by 24 h following LPS administration. Ribonuclease protection experiments demonstrated very low levels of plasma-type PAF-acetylhydrolase mRNA transcripts in the livers of saline-infused rats; however, 24 h following LPS exposure, a 20-fold induction of PAF-acetylhydrolase mRNA was detected. In cells isolated from endotoxin-exposed rat livers, Northern blot analyses demonstrated that Kupffer cells but not hepatocytes or endothelial cells were responsible for the increased PAF-acetylhydrolase mRNA levels. In Kupffer cells, plasma-type PAF-acetylhydrolase mRNA was induced by 12 h, peaked at 24 h, and remained substantially elevated at 48 h. Induction of neutropenia prior to LPS administration had no effect on the increase in PAF-acetylhydrolase mRNA seen at 24 h. Although freshly isolated Kupffer cells contain barely detectable levels of plasma-type PAF-acetylhydrolase mRNA, when Kupffer cells were established in culture, PAF-acetylhydrolase expression became constitutively activated concomitant with cell adherence to the culture plates. Alterations in plasma-type PAF-acetylhydrolase expression may constitute an important mechanism for elevating plasma PAF-acetylhydrolase levels and an important component in minimizing PAF-mediated pathophysiology in livers exposed to endotoxemia.

Endothelin-1 production by hepatic endothelial cells: characterization and augmentation by endotoxin exposure

Activation of endothelin (ET) receptors in the liver causes vasoconstriction, glucose production, and lipid and peptide mediator synthesis. In the intact rat, a bolus infusion of endotoxin into a mesenteric vein served as an acute exposure model of endotoxemia. In response to this challenge, a ninefold increase in hepatic ET-1 mRNA occurred within 3 h. The plasma level of immunoreactive ET-1 (irET-1) increased correspondingly by 8.5-fold within 6 h. ET-1 mRNA levels in liver endothelial cells (EC) isolated from livers of endotoxin-treated rats at various times after endotoxin challenge showed a more gradual increase. Northern blot analyses of the major liver cell types demonstrated that ET-1 mRNA was most abundant in the EC. The present results document a significant increase in the circulating level of irET-1 during episodes of endotoxemia. The increased hepatic ET-1 production in response to endotoxin infusion suggests that ET-1 produced in the liver could make a significant contribution to the plasma irET-1 and may be an important component in the hepatic responses to systemic trauma.

Erythrocyte incorporation and absorption of 58Fe in premature infants treated with erythropoietin

We hypothesized that treatment of very low birth weight premature infants with r-HuEPO would increase erythrocyte incorporation and gastrointestinal absorption of iron. Infants with birth weights < or = 1.25 kg and gestational ages < 31 wk were randomized to receive 6 wk of 500 U of r-HuEPO/kg/wk (epo group, n = 7) or placebo (placebo group, n = 7). All infants received daily enteral supplementation with 6 mg of elemental iron per kg. An enteral test dose of a stable iron isotope, 58Fe, was administered after the 1st ("early dosing") and 4th ("late dosing") wk of treatment. Mean (+/-SD) erythrocyte incorporation of the dose of 58Fe administered determined 2 wk after early dosing was significantly greater in the epo group compared with the placebo group (4.4% +/- 1.6 versus 2.0 +/- 1.4%, p = 0.013). In contrast, after late 58Fe dosing, there was no difference between groups in incorporation (3.8 +/- 1.6% versus 5.5 +/- 2.7%). Within the epo group, percentage erythrocyte incorporation of 58Fe did not differ between early and late dosing, whereas in the placebo group it increased 3-fold (p < 0.01). Percentage absorption of 58Fe was not different between the epo and placebo groups after both early dosing (30 +/- 22% versus 34 +/- 8%) and late dosing (32 +/- 9% versus 31 +/- 6%). Absorption of nonlabeled elemental iron and 58Fe were significantly correlated with one another. The percentage of the absorbed 58Fe dose incorporated into Hb was not different between groups. We conclude that, although erythropoietin treatment stimulates erythrocyte iron incorporation in premature infants, it has no effect on iron absorption at the r-HuEPO dose studied.