Increased vertical transmission of human immunodeficiency virus from hepatitis C virus-coinfected mothers. Women and Infants Transmission Study

To determine if hepatitis C virus (HCV) infection affects vertical transmission of human immunodeficiency virus (HIV), 487 HIV-infected pregnant women in the prospective, multicenter, Women and Infants Transmission Study had HCV antibody (anti-HCV by second-generation ELISA) and HCV RNA (by quantitative polymerase chain reaction) measured in peripartum maternal plasma; 161 (33%) were anti-HCV-positive. HIV vertical transmission occurred from 42 HCV-infected mothers (26.1%) versus 53 HCV-uninfected mothers (16.3%; odds radio [OR], 1.82; P = .01). In a logistic regression model that included maternal drug use, a potential confounder, HCV infection was marginally associated with perinatal HIV transmission (OR, 1.64; P = .05), whereas drug use was not. Women who transmitted HIV had higher levels of HCV RNA (median, 721,254 copies/mL) than those who did not (337,561 copies/mL; P = .01). Maternal HCV infection is associated with increased HIV vertical transmission. Further studies are needed to ascertain if HCV directly affects perinatal HIV transmission or is a marker for another factor, such as maternal drug use.

Seroreactivity to hepatitis E virus in areas where the disease is not endemic

If the occurrence of hepatitis E virus antibody (anti-HEV) in regions where the disease is not endemic represents infection, rates may be greater in high-risk populations and behavioral correlates may reflect recognized transmission modes. Serum samples from 300 homosexual males, 300 injection drug users (IDUs), and 300 blood donors from Baltimore, Md., were tested for anti-HEV by enzyme immunoassay. Anti-HEV was found in an unexpectedly high percentage of homosexual men (15.9%) and IDUs (23.0%). However, anti-HEV was present in a similar proportion of blood donors (21.3%) (P > 0.05), while hepatitis A, B, and C virus antibodies were more prevalent in the high-risk groups (P < 0.001). Among homosexual men, anti-HEV was not significantly correlated with a history of hepatitis, high-risk sexual practices, or sexually transmitted infections, in contrast to hepatitis A and B antibodies. Among IDUs, anti-HEV was not significantly associated with a history of hepatitis or high-risk drug-using practices, as was found with hepatitis C antibodies. In a setting without endemic hepatitis E disease, there was no evidence that anti-HEV reflected subclinical infection. Until the basis for HEV seroreactivity in such areas is elucidated, anti-HEV results should be interpreted with caution.

Genetic analysis of discrete reproductive traits in sheep using linear and nonlinear models: II. Goodness of fit and predictive ability

The performance of linear and nonlinear sire and animal models in the analyses of reproductive traits (fertility, litter size, and ovulation rate) in two sheep populations (Rambouillet and Finnsheep) was compared in terms of goodness of fit and predictive ability. Linear sire (LSM) and animal (LAM) models were used with all traits. Nonlinear models were the threshold, Poisson, and negative binomial. Threshold sire (TSM) and animal (TAM) models were also used with all traits. Litter size and ovulation rate were analyzed also with Poisson and negative binomial sire (PSM and NBSM, respectively) and animal (PAM and NBAM, respectively) models. Variance components were those reported in the companion article. For PAM a new set of variance components derived from estimates found with the linear animal model also was used (PAM-L). Mean squares error (MSE) and correlations between fitted and observed values were used to assess goodness of fit. Predictive ability was assessed by partitioning the data sets for the different traits into two subsets with the restriction that all levels of fixed effects were represented in each subset. Parameters from one subset were employed to predict observations in the other, and then MSE and correlations between observed and predicted values were used as criteria for model comparison. Within estimation procedure, breed, and trait, goodness of fit of sire and animal models was similar. Linear and threshold models resulted in similar fit, and both outperformed Poisson and negative binomial models. In terms of predictive ability, linear and threshold models performed only slightly better than Poisson and negative binomial models. Goodness of fit and predictive ability generally were better when models included permanent environmental effects.

Genetic analysis of discrete reproductive traits in sheep using linear and nonlinear models: I. Estimation of genetic parameters

Repeated records on fertility, litter size, and ovulation rate of Rambouillet ewes and on fertility and litter size of Finnsheep ewes were used to estimate heritabilities and repeatabilities with linear and nonlinear sire and animal models. Linear sire (LSM) and animal models were used with all traits. Nonlinear models were the threshold, Poisson, and negative binomial. Threshold sire (TSM) and animal models were used with all traits. Litter size and ovulation rate were analyzed also with Poisson sire and animal models and with negative binomial sire and animal models. Variance components for linear models were estimated using REML; in the threshold, Poisson, and negative binomial, they were estimated using approximate marginal maximum likelihood. Poisson and negative binomial analyses yielded results difficult to interpret due to problems in variance component estimation. Animal models resulted in slightly greater estimates of heritability for fertility than did sire models, but ovulation rate heritability estimates from sire models were much greater than estimates form animal models. Differences between sire and animal models for heritability estimates for litter size were not consistent. Threshold models resulted in higher heritability estimates for all traits in both breeds and with both sire and animal models. In general, repeatabilities were consistent across models. For example, LSM (TSM) repeatabilities were .10 (.14) for fertility, .20 (.25) for litter size, and .25 (.29) for ovulation rate in the Rambouillet, and .17 (.17) for fertility and .11 (.13 for litter size in the Finnsheep.

Effects of passive immunization against inhibin-peptide on secretion of follicle-stimulating hormone and ovulation rate in ewes carrying the Booroola fecundity gene

Objectives of the study were to determine whether 1) inhibin negative feedback regulation of FSH secretion is diminished in ewes carrying a copy of the Booroola fecundity (FecB) gene and 2) differential FSH secretion is obligatory for expression of gene-specific differences in ovulation rate (OR). The approach was to compare FSH and ovulatory responses to passive immunoneutralization of inhibin in ewes with and without a copy of the FecB gene. Twenty-eight 2- to 3-yr-old ewes were assigned within genotype to antibody (alpha-IF-Ab) or control groups. Genotypes consisted of 3/4 Rambouillet x 1/4 Booroola ewes with one copy of the FecB gene (FecB+; 57 kg) and 3/4 Rambouillet x 1/4 Booroola ewes without the FecB gene (++; 59 kg). Estrus was synchronized during the breeding season using progesterone-releasing pessaries (CIDR-G). Pessaries were removed at 0 h. A single injection of alpha-IF-Ab or control solution was given at -48 h. Alpha-IF-Ab had been developed against a synthetic inhibin fragment matching the N-terminal region of ovine inhibin's alpha subunit. For injection, alpha-IF-Ab had been precipitated from ovine immune sera and concentrated. Blood samples were collected at 6-h intervals from -48 to 48 h, and laparoscopy was performed 14 days after CIDR-G withdrawal. All ewes exhibited estrus and ovulated. Genotype and alpha-IF-Ab treatment were without effect on intervals to estrus. Both factors affected OR (p < or = 0.001). Mean OR in control ++ and FecB+ ewes were 1.6 and 2.7, respectively; mean OR in alpha-IF-Ab-treated ++ and FecB+ ewes were 2.5 and 4.6, respectively. Following injection of alpha-IF-Ab, FSH concentrations increased within 6 h, peaked 12-18 h later, and then declined. Magnitude of FSH increases was similar in ++ and FecB+ ewes (70% and 85% over control values, respectively). Results demonstrate that 1) inhibin negative feedback regulation of FSH secretion is not a site of FecB gene action and 2) the mechanism by which the FecB gene increases OR does not necessarily involve increased FSH secretion during the period of preovulatory follicular development.

Assessment of lamb carcass composition from live animal measurement of bioelectrical impedance or ultrasonic tissue depths

Market weight lambs, average weight 52.5 kg (+/-6.1), were used to evaluate nontraditional live animal measurements as predictors of carcass composition. The sample population (n = 106) represented U.S. market lambs and transcended geographic location, breed, carcass weight, yield grade, and production system. Realtime ultrasonic (RU) measurements and bioelectrical impedance analysis (BIA) were used for development and evaluation of prediction equations for % boneless, closely trimmed primal cuts (BCTPC), weight or % of dissected lean tissue (TDL), and chemically derived weight or % fat-free lean (FFL). Longitudinal ultrasonic images were obtained parallel to the longissimus thoracis et lumborum (LTL), positioning the last costae in the center of the transducer head. Images were saved and fat and LTL depths were derived from printed images of the ultrasonic scans. Bioelectrical impedance analysis was administered via a four-terminal impedance plethysmograph operating at 800 microA at 50 kHz. Impedance measurements of whole-body resistance and reactance were recorded. Prediction equations including common linear measurements of live weight, heart girth, hindsaddle length, and shoulder height were also evaluated. All measurements were taken just before slaughter. Bioelectrical impedance measurements (as compared to RU and linear measurements) provided equations for %BCTPC, TDL, %TDL, FFL and %FFL with the highest R2 and lowest root mean square error. Even though BIA provided the best equations of the three methodologies tested, prediction of proportional yield (%BCTPC, %TDL, and %FFL) was marginal (R2 = .296, .551, and .551, respectively). Equations combining BIA, RU, and linear measurements greatly improved equations for prediction of proportional lean yield.

Effect of human immunodeficiency virus on hepatitis C virus infection among injecting drug users

To assess the effect of human immunodeficiency virus (HIV) immunosuppression on ongoing hepatitis C virus (HCV) infection, CD4 lymphocyte counts and serum concentrations of HCV RNA, HIV RNA, and alanine aminotransferase (ALT) were evaluated among members of a cohort of injecting drug users (IDUs). With 100 participants randomly selected at various stages of HIV-related immunosuppression, serum HCV RNA concentrations increased with age (P = .007) and were higher in HIV-positive IDUs with 201-500 (P = .026) and 51-200 (P = .004) CD4 cells/mL than in HIV-negative participants. Among 27 HCV-infected IDUs who acquired HIV infection, serum HCV RNA concentrations varied between semiannual visits by a mean of 0.45 logs, increasing by 0.60 logs after HIV seroconversion (P < .0001), by 0.12 logs each subsequent year (P = .006), and by 0.36 logs per log increase in CD4 cells (P = .01). Serum ALT levels were similar between HIV-positive (40.1 IU/mL) and HIV-negative (45.4 IU/mL) patients (P > .10). While HIV infection and possibly HIV progression are associated with increased HCV RNA levels, other factors appear to affect biochemical and virologic markers of HCV infection in some dually infected persons.

Clinical characterization of a competitive PCR assay for quantitative testing of hepatitis C virus

Rational clinical application of quantitative assessments of hepatitis C virus (HCV) RNA depends on an understanding of factors affecting the assay and its intrinsic variability. The effects of three types of blood collection tubes, two storage temperatures, five processing times, and two laboratories on a commercially available quantitative reverse transcriptase PCR assay (AMPLICOR HCV MONITOR) were evaluated. HCV RNA concentrations were assessed in 356 specimens representing 178 aliquots from nine patients. In a multivariate generalized linear model, HCV RNA concentrations decreased when centrifugation was delayed more than 6 h (P = 0.005) and were marginally different between laboratories (P = 0.06), but precentrifugation storage temperature (P = 1.00) and anticoagulation (P = 0.22) had no effect. After adjusting for other factors, the HCV concentration of 95% of a subject's samples were within 0.44 log. Specimens procured for reverse transcriptase PCR-based quantitative HCV testing should be centrifuged within 6 h of collection. Serial assessments should ideally be performed in the same laboratory, and changes in HCV RNA concentration of less than 0.44 log may not be biologically important.

Occupational risk of hepatitis C infections among general dentists and oral surgeons in North America

PURPOSE

To assess the occupational risk of hepatitis C virus (HCV) infection among dental personnel.

METHODS

Three hundred forty-three oral surgeons and 305 general dentists were recruited at national meetings of the American Dental Association and matched by gender, age, years of practice, and location of practice. Each participant completed a detailed questionnaire designated to measure occupational risk of blood-borne infections and supplied a sample of blood. Antibodies to HCV (anti-HCV) were assessed by second-generation enzyme immunoassay and recombinant immunoblot assay. As a marker of occupational exposure to blood-borne viruses, hepatitis B virus (HBV) surface antigen and antibodies to HBV surface and core antigens were measured by enzyme immunoassay.

RESULTS

Anti-HCV was found in 2.0% of oral surgeons and 0.7% of general dentists (odds ratio [OR] = 3.2, P = 0.133). Anti-HCV was more prevalent (P < 0.01) in dental personnel who were older, had more years of practice, and had serologic markers of HBV infection. Serologic markers of HBV infection were found in 7.8% of general dentists and 21.2% of oral surgeons (OR 3.1, P < 0.001).

CONCLUSIONS

These data confirm high rates of HBV infection among dental personnel, but suggest that the risk of HCV infection is considerably lower.

Performance of hair breeds and prolific wool breeds of sheep in southern Illinois: wool production and fleece quality

The objective of this study was to compare weight and quality of fleeces of different F1 ewe types produced from breeds with a broad range of fleece types. Weights of 629 fleeces produced during 1988 through 1991 from F1 ewes that were daughters of Suffolk and Targhee dams and Finnsheep, Combo-6, Booroola Merino, St. Croix, and Barbados sires were recorded. Staple length was measured on the mid-side of each ewe present in 1991. Fleeces shorn in 1991 were sent to a wool marketing organization, and staple length, wool grade, and clean fleece yield were subjectively estimated (n = 220). Mid-side fleece samples were collected from no more than two randomly selected ewes from each subclass (breed of dam-breed of sire-age of ewe) in 1991 (n = 78) and sent to a wool laboratory where fiber diameter, yield, and percentage of colored, med, and kemp fibers were objectively determined. Ewes from Targhee dams produced fleeces with greater weight, greater fiber length, smaller fiber diameter, lower yield, and fewer colored fibers than ewes from Suffolk dams (all differences significant, P < .01). Booroola Merino-sired ewes produced heavier (P < .01) fleeces than did Finnsheep- and Combo-6-sired ewes (4.13 and 3.09 kg, respectively), and in turn, Finnsheep- and Combo-6-sired ewes produced heavier (P < .01) fleeces than did ewes sired by hair breed rams (3.09 and 1.70 kg, respectively). Among hair breed-sired ewes, St. Croixsired ewes produced heavier (P < .01) fleeces than did Barbados-sired ewes (1.88 and 1.52 kg, respectively). Fleeces produced by Booroola Merino-sired ewes had smaller (P < .01) fiber diameter than all sire breed groups except Combo-6-sired ewes, and fleeces produced by St. Croix-sired ewes had greater (P < .01) fiber diameter than all other sire breed groups. Lab scoured yield was greater (P < .01) for fleeces from ewes from hair breed than for fleeces from ewes from wool breed sires (74.2 vs 66.1%). Proportions of undesirable fibers (med, kemp, and colored) were 20 to 600 times greater (P < .01) in fleeces of ewes from hair breed sires than in fleeces of ewes from wool breed sires. In general, F1 ewes from Booroola Merino sires produced the heaviest, highest quality fleeces, and ewes from the hair breed sires of St. Croix and Barbados produced the lightest, lowest quality fleeces. Ewes from Finnsheep and Combo-6 sires produced fleeces that were more similar to the fleeces of ewes from Booroola Merino sires than to the fleeces of ewes from the hair breed sires.

Correlates of hepatitis C virus infections among injection drug users

Injection drug users are at high risk for hepatitis C virus (HCV) infection. In Baltimore, Maryland, the prevalence of anti-HCV is greater among injection drug users who are black, human immunodeficiency virus (HIV) infected, have injected longer, have injected more frequently, and have injected cocaine than among other injection drug users. HCV infection occurs quickly after the initiation of injecting illicit drugs, with 78% of study participants anti-HCV positive after 2 years of injecting. The prevalence of anti-HCV among injection drug users does not appear to be related to socioeconomic factors or sexual practices. Some injection drug users remain free of anti-HCV even after years of injecting and serologic evidence of other bloodborne pathogens. Some of these injection drug users have HCV infection, demonstrated by HCV RNA in their sera. However, the basis for viral persistence in the absence of anti-HCV and for the absence of HCV infection in long-term drug users is not known. Further studies are indicated to determine the mechanism or mechanisms for the absence of anti-HCV in persons exposed to the virus, because the biologic basis for this condition may elucidate the elements missing in the immune response of the majority of HCV-exposed persons who acquire persistent infection. In addition, interventions to prevent HCV infections should be applied in populations at risk for injection drug use early or before drug use begins.

High prevalence of hepatitis C in Egyptian patients with chronic liver disease

The highest prevalence rates of hepatitis C virus infection in the world have been recently reported among Egyptian blood donors and frequent recipients of transfusions and other blood products. This is the first report, however, demonstrating hepatitis C as the most frequent association with chronic liver disease in Egypt. Of 1023 patients referred to the Liver Institute in Menoufia governorate for evaluation of chronic liver disease, 752 (73.5%) had antibodies to hepatitis C compared with 168 (16.4%) with hepatitis B surface antigen. Hepatitis C antibody was more common in patients with active schistosomiasis and patients without hepatitis B surface antigenaemia. Of 100 patients having liver biopsies, histological findings consistent with chronic viral hepatitis or its complications were found in 89 and antibody to hepatitis C was present in 75 (84.3%) of these patients with chronic hepatitis, active cirrhosis or hepatocellular carcinoma. These data pointing to the importance of hepatitis C as a cause of chronic liver disease in Egypt emphasise the necessity of studies delineating its routes of transmission in this country.

Performance of hair breeds and prolific wool breeds of sheep in southern Illinois: lamb production of F1 adult ewes

Two- and three-year-old F1 crossbred ewes produced from Suffolk and Targhee dams and sires of the prolific wool breeds of Finnsheep, Combo-6, and Booroola Merino and the hair breeds of St. Croix and Barbados were pasture-mated to Dorset rams over a 4-yr period at the Dixon Springs Agricultural Center in Southern Illinois. Booroola Merino sires were homozygous for the FecB allele for high number of ovulations. The effects of age of ewe, sex of lamb (where appropriate), breed of dam, and breed of sire on condition score, breeding weight, ovulation rate, breeding to lambing interval, fertility, prolificacy, lamb survival, weaning weight, and ewe productivity were estimated. All traits were analyzed using mixed-model methodology. Crossbred ewes from Suffolk dams had a higher (P < .01) condition score, heavier (P < .01) breeding weight, higher (P < .01) ovulation rate, shorter (P < .01) breeding to lambing interval, greater (P < .01) prolificacy, heavier (P < .01) lambs at weaning, and greater (P < .05) ewe productivity than crossbred ewes from Targhee dams. Ewes from hair-breed sires had lighter (P < .01) breeding weight, lower (P < .05) ovulation rate, shorter (P < .05) breeding to lambing interval, higher (P < .05) fertility, higher (P < .05) lamb survival, lower (P < .10) lamb weaning weight, and higher (P < .05) ewe productivity than ewes sired by the prolific wool-breed rams. The breed of sire x breed of dam interaction was a significant source of variation for breeding weight, fertility, lamb survival, and ewe productivity.(ABSTRACT TRUNCATED AT 250 WORDS)

Sexual transmission of hepatitis C virus among patients attending sexually transmitted diseases clinics in Baltimore--an analysis of 309 sex partnerships

The prevalence of antibodies to hepatitis C virus (anti-HCV), the behavioral and laboratory-derived risk factors for anti-HCV, and the quantity and homology of HCV RNA were assessed among 1039 non-injection drug-using sexually transmitted disease (STD) patients representing 309 sex partnerships. Thirty-seven (7%) of 555 males and 19 (4%) of 484 females had anti-HCV. In logistic regression analyses, factors associated with anti-HCV included age (P < .001), greater numbers of lifetime sex partners (P = .023), human immunodeficiency virus infection (P < .001), Trichomonas infection (P < .001), cigarette smoking (P < .001), and male homosexual exposure (P = .012). Among couples, females whose sex partners were anti-HCV positive were 3.7 times more likely to have anti-HCV than females whose sex partners were anti-HCV negative (P = .039). The proportion of RNA homology between anti-HCV positive females and their male partners (94%) was higher than among randomly selected patients (82%). Sexual transmission of HCV may contribute to the high prevalence of anti-HCV reported in urban settings.

Mechanism of cellulose synthesis in Agrobacterium tumefaciens

Extracts of Agrobacterium tumefaciens incorporated UDP-[14C]glucose into cellulose. When the extracts were fractionated into membrane and soluble components, neither fraction was able to synthesize cellulose. A combination of the membrane and soluble fractions restored the activity found in the original extracts. Extracts of cellulose-minus mutants showed no significant incorporation of UDP-glucose into cellulose. When mixtures of the extracts were made, the mutants were found to fall into two groups: extracts of mutants from the first group could be combined with extracts of the second group to obtain cellulose synthesis. No synthesis was observed when extracts of mutants from the same group were mixed. The groups of mutants corresponded to the two operons identified in sequencing the cel genes (A. G. Matthysse, S. White, and R. Lightfoot. J. Bacteriol. 177:1069-1075, 1995). Extracts of mutants were fractionated into membrane and soluble components, and the fractions were mixed and assayed for the ability to synthesize cellulose. When the membrane fraction from mutants in the celDE operon was combined with the soluble fraction from mutants in the celABC operon, incorporation of UDP-glucose into cellulose was observed. In order to determine whether lipid-linked intermediates were involved in cellulose synthesis, permeablized cells were examined for the incorporation of UDP-[14C]glucose into material extractable with organic solvents. No radioactivity was found in the chloroform-methanol extract of mutants in the celDE operon, but radioactive material was recovered in the chloroform-methanol extract of mutants in the celABC operon. The saccharide component of these compounds was released after mild acid hydrolysis and was found to be mainly glucose for the celA insertion mutant and a mixture of cellobiose, cellotriose, and cellotetrose for the celB and celC insertion mutants. The radioactive compound extracted with chloroform-methanol form the celC insertion mutant was incorporated into cellulose by membrane preparations from celE mutants, which suggests that this compound is a lipid-linked intermediate in cellulose synthesis.

Association of hepatitis C virus infection with false-positive tests for syphilis

The prevalence of false-positive reactions for syphilis (reactive rapid plasma reagin [RPR] test and nonreactive fluorescent treponemal antibody absorption [FTA-ABS] test) among patients at sexually transmitted disease (STD) clinics was assessed to evaluate the association between false-positive RPR reactions and hepatitis C virus (HCV) infections. Among 2672 patients, 400 (15.0%) had antibodies to HCV (anti-HCV) and 254 (9.5%) had a reactive RPR test. Of the 254 reactive RPR tests, 231 (90.1%) were also positive by FTA-ABS, leaving 23 false-positive RPR reactions. After excluding the 231 patients with positive FTA-ABS tests, false-positive RPR tests were found in 9 (2.7%) of 330 anti-HCV-positive patients compared with 14 (0.6%) of 2154 anti-HCV-negative participants (relative risk, 4.5; 95% confidence interval, 1.9-10.9; P = .0017). These data demonstrate that HCV infection is associated with false-positive RPR test results. However, because of the high prevalence of syphilis among STD patients, the RPR test remains a strong indicator of syphilis in this setting.

The epidemiology of hepatitis C in Turkey

Hepatitis C virus (HCV) and hepatitis E virus (HEV) are the principal causes of non-A, non-B hepatitis worldwide, and in Turkey one-third of the cases of acute hepatitis are non-A, non-B. To explore the epidemiology of HCV in Turkey (including the association of HCV with HEV), a seroprevalence study of HCV was conducted. Sera from residents from five distinct regions of the country were tested for antibodies to HCV (anti-HCV) and HEV (anti-HEV). Anti-HCV was detected in 21 (1.5%) of 1,374 persons and was more common in residents over 54 years of age (p = 0.02), with less than primary education (p = 0.013), more than two children (p = 0.003), and who lived in the regions of Ayvalik (p = 0.046) or Trabzon (p = 0.038) compared to Istanbul. Anti-HCV was marginally associated with anti-HEV, which was found in 5.9% of residents. However, this association was lost after controlling for age and education (p = 0.225). HCV infection occurs in all regions of Turkey and is more common in persons who are older and of low socioeconomic status. As resources permit, efforts to reduce the transmission of HCV in Turkey (such as screening blood donations for anti-HCV) are indicated.

High seroprevalence of hepatitis C infection among risk groups in Egypt

High prevalence rates of hepatitis C virus (HCV) were recently reported among Egyptian blood donors. To confirm these observations and estimate the magnitude of HCV infection in this country, we determined the prevalence of antibodies to HCV (anti-HCV) in samples collected in 1992 from seven different populations of children and adults living in Egypt. Anti-HCV was found in 12.1% of rural primary schoolchildren, 18.1% of residents of a rural village, 22.1% of army recruits, 16.4% of children with hepatosplenomegaly, 54.9% of hospitalized, multitransfused children, 46.2% of adults on hemodialysis, and 47.2% of adults with chronic liver disease or hepatoma. Age-related prevalence of anti-HCV in a random sample of 270 inhabitants of a rural village increased progressively from zero in those 5-10 years of age to 41% in adults greater than the age of 50. Although the increased prevalence of anti-HCV among children and adults with parenteral exposures and chronic liver disease was expected, the prevalence of anti-HCV among persons representing the general population of Egypt was strikingly high. These data demonstrate the magnitude of HCV infection and its importance in chronic liver disease in Egypt. Future studies are needed to determine the routes of transmission of HCV in this country.

Electromagnetic scanning to predict lamb carcass composition

The electromagnetic scanner generates a constant, low-level electromagnetic field (2.5 MHz) within a large plexiglass tube. The amount of electromagnetic (EM) energy transferred (to the carcass) is highly related to lean tissue. A plot of the absorption units over distance can be used to assess the total mass of lean tissue and of the respective primal cuts. The difference in curve height between two points (D), peak phase absorption, and linear carcass measurements (pre-rigor, HCWT or post-rigor, CWT carcass weight, and carcass length, LENG) were used to predict total dissected lean (TOTLEAN), dissected leg lean (LEGLEAN), and percentage of dissected carcass lean (PERLEAN). Twenty-one pre-rigor and 22 post-rigor (24 h chill) lamb carcasses, average weight 26.8 (+/- 4.2 kg) and 26.4 (+/- 4.1 kg) kg, respectively, were evaluated from measurements of total body electrical conductivity (TOBEC). Two geometric orientations were tested for statistical accuracy in this study: A) each carcass entered the EM tunnel rear leg first, on its left lateral side, neck facing the right side of the tunnel; and B) each carcass entered the EM tunnel rear leg first, breast down, and neck up. Orientation A proved more statistically efficient for pre-rigor carcasses, and orientation B was more desirable for post-rigor carcasses. Multiple-regression models involving HCWT, LENG, and a single D measure accounted for 98.0 and 95.0%, respectively, of the total variation in pre-rigor carcass TOTLEAN and LEGLEAN in A.(ABSTRACT TRUNCATED AT 250 WORDS)

A comparison of normal and nonnormal mixed models for number of lambs born in Norwegian sheep

A comparison of linear (LM), threshold (TM), and Poisson (PM) mixed models for genetic analysis of number of lambs born (NLB) from 1-yr-old ewes was conducted using 37,718 and 18,633 records of two Norwegian breeds, Dala and Spaelsau, respectively. Models fitted included flock-year as a fixed effect and the random effect of sire. In the Poisson model, the residual variation was assumed to be Poisson, whereas it was normal in LM and multinomial in TM. The models were compared with respect to goodness of fit, predictive ability, and ranking of sires. Goodness of fit and predictive ability were assessed via the mean squared error and the correlation between observed NLB and fitted (predicted) values. Predictive ability was evaluated by estimating effects of sire and flock-year using a random half of the data and then using these estimates to predict records on the other half of the data. The heritability of NLB for Dala was estimated to be .20, .39, and .08 with LM, TM, and PM, respectively. For Spaelsau, corresponding estimates were .12, .26, and .00, respectively. In the PM, problems of low or zero estimates of sire variances were encountered. Hence, an alternative sire variance (PM-L) was approximated from the heritability estimated on the outward scale by REML. All models performed similarly with respect to goodness of fit, predictive ability, and ranking of sires. The TM was very slightly better for both breeds, but the PM and PM-L seemed clearly poorer than TM and LM. An approximate test rejected the hypothesis that the conditional distribution of NLB was Poisson.

Hepatitis C, hepatitis B, and human immunodeficiency virus infections among non-intravenous drug-using patients attending clinics for sexually transmitted diseases

The seroprevalences of and risk factors for hepatitis C virus (HCV), hepatitis B virus (HBV), human immunodeficiency virus (HIV), and syphilis were determined among 1257 consecutive non-intravenous drug-using patients attending Baltimore sexually transmitted diseases clinics: 122 (9.7%) had antibodies to HCV (anti-HCV), 192 (15.3%) had antibodies to HBV (anti-HBc), 44 (3.5%) had antibodies to HIV (anti-HIV), and 60 (4.8%) were seropositive for syphilis. For males, independent predictors of anti-HCV were age > 29 years and lack of condom use in the month before their visit. Males with any one serologic marker (anti-HCV, anti-HBc, anti-HIV, or syphilis) were more likely to have each of the other markers. For females, anti-HCV was independently associated with age > 29 years and > 1 male sex partner in the prior month. Females with anti-HIV or anti-HBc were more likely to have anti-HCV. These observations among non-intravenous drug-using patients suggest that sexual transmission of HCV may occur.

Serologic testing for sexually transmitted diseases

This article addresses current issues regarding serologic testing for selected STDs, particularly those for which serologic testing has been useful for diagnosis, monitoring therapy, or seroepidemiology. For each selected pathogen, the authors discuss the strengths and weaknesses of the serologic tests as diagnostic assays, as measures of disease incidence and relevance, and as prospective markers identifying risk alterations in a given population. Also, for some conditions such as syphilis, the usefulness of serology as a measure of therapy or success of disease intervention is briefly outlined.