Hepatitis C virus infection and risk factors in health-care workers at Ain Shams University Hospitals, Cairo, Egypt

The objectives of this study were to document the background prevalence and incidence of HCV infection among HCWs in Ain Shams University Hospitals in Cairo and analyse the risk factors for HCV infection. A cross-sectional survey was conducted in 2008 among 1770 HCWs. Anti-HCV prevalence was age-standardized using the Cairo population. A prospective cohort was followed for a period of 18 months to estimate HCV incidence. The crude anti-HCV prevalence was 8.0% and the age-standardized seroprevalence was 8.1%. Risk factors independently associated with HCV seropositivity were: age, manual worker, history of blood transfusions and history of parenteral anti-schistosomiasis treatment. The estimated incidence of HCV infection was 7.3 per 1000 person-years. HCWs in this setting had a similar high HCV seroprevalence as the general population of greater Cairo.

Prevalence of hepatitis B and C virus infections and their related risk factors in Libya: a national seroepidemiological survey

A high prevalence of hepatitis B (HBV) and C virus (HCV) infections has been reported among specific patient groups in Libya; a survey was thus designed to determine the extent of the problem at the national level. A multi-stage sampling design covering all administrative areas of Libya was applied, covering > 65,000 individuals of all age groups. All subjects gave a blood sample and completed a questionnaire on demographic and risk behaviour data. The prevalence of HBV surface antigen (HBsAg) and anti-HCV were 2.2% and 1.3% respectively. The prevalence of anti-HCV increased with age, rising gradually after age 30 years, in contrast to a stable prevalence of HBsAg in all age groups 10+ years. Age-adjusted risk factors for HCV infection were previous hospitalization, surgical operations, previous blood transfusions and intravenous drug use; for HBV infection only family exposure or contact with HBV case were identified.

Towards realistic estimates of HCV incidence in Egypt

Accurate incidence estimates are essential for quantifying hepatitis C virus (HCV) epidemic dynamics and monitoring the effectiveness of public health programmes, as well as for predicting future burden of disease and planning patient care. In Egypt, the country with the largest HCV epidemic worldwide, two modelling studies have estimated age-specific incidence rates that, applied to the age pyramid, would correspond to more than 500 000 Egyptians getting infected annually. This is in contrast to figures of the Egyptian Ministry of Health and Population that estimates new infections to be approximately 100 000 per year. We performed new analyses of nationwide data to examine the modelling assumptions that led to these estimates. Thus, we found that the key assumption of these models of a stationary epidemic is invalid. We propose an alternate approach to estimating incidence based on analysing cohort data; we find that the number of annual new infections is <150 000.

HCV burden of infection in Egypt: results from a nationwide survey

Egypt is the country with the largest hepatitis C virus (HCV) epidemic in the world. In 2008, a Demographic Health Survey (DHS) was carried out in Egypt, providing for the first time a unique opportunity for HCV antibody testing on a nationwide representative sample of individuals. Consenting individuals answered a questionnaire on socio-demographic characteristics and iatrogenic exposures, before providing a blood sample for HCV antibody testing by enzyme-linked immunosorbent assay. Factors independently associated with HCV infection were examined through multivariate logistic regression models. Of 12 780 eligible subjects aged 15-59 years, 11 126 (87.1%) agreed to participate and provided a blood sample. HCV antibody prevalence nationwide was 14.7% (95% CI 13.9-15.5%) in this age group. HCV antibody prevalence gradually increased with age, reaching, in the 50-59 years age group, 46.3% and 30.8% in males and females, respectively. It was higher in males compared to females (17.4% versus 12.2%, respectively, P < 0.001), and in rural compared to urban areas (18.3% versus 10.3%, respectively, P < 0.001). In multivariate analysis, age, male sex, poverty, past history of intravenous anti-schistosomiasis treatment, blood transfusion, and living outside of the Frontier Governorates were all significantly associated with an increased risk of HCV infection. In addition, in urban areas, lack of education and being circumcised for females were associated with an increased risk of HCV infection. This study confirmed on a nationwide representative sample the very high HCV antibody prevalence in Egypt. It stresses the urgent need for strengthening prevention efforts, and bringing down the costs of antiviral drugs for countries like Egypt, where the people in the most precarious situations are also those most likely to be infected by the virus.

Epidemiological and virological characteristics of symptomatic acute hepatitis E in Greater Cairo, Egypt

The aim of the study was to describe the characteristics of acute hepatitis E in Greater Cairo. Patients with acute hepatitis E were identified through a surveillance of acute hepatitis using the following definition: recent (<3 weeks) onset of fever or jaundice, alanine aminotransferase at least three times the upper limit of normal (uln), negative markers for other causes of viral hepatitis and detectable hepatitis E virus (HEV) RNA. Comparison of the liver tests between acute hepatitis E and hepatitis A virus (HAV), case-control analysis (four sex-matched and age-matched (±1 year) HAV controls per case) to explore risk factors and phylogenetic analyses were performed. Of the 17 acute HEV patients identified between 2002 and 2007, 14 were male. Median age was 16 years (interquartile range 13-22). Compared with HAV (n = 68 sex-matched and ±1 year age-matched), HEV patients had higher bilirubin (mean (SD) 10.9 (5.7) uln versus 7.5 (4.4) uln, p 0.05) and aspartate aminotransferase levels (38.6 (27.1) uln versus 18.3 (18.1) uln, p 0.02). Co-infection (hepatitis C virus RNA or hepatitis B surface (HBs) -antigen positive/IgM anti-hepatitis B core (HBc) anitgen negative) was diagnosed in four patients. In univariate matched analysis (17 cases, 68 matched controls), HEV cases were more likely to live in a rural area than HAV controls (matched OR 7.9; 95% CI 2.0-30.4). Of the 16 isolates confirmed as genotype 1, 15 belonged to the same cluster with 94-98.5% identity in the open-reading frame 2 region. Our findings documented the sporadic nature of HEV in Greater Cairo, characterized a large number of Egyptian HEV genotype 1 strains and identified living in a rural area as a potential risk factor for infection.

Assessment of tobacco dependence in waterpipe smokers in Egypt

SETTING

Waterpipe smoking is increasing worldwide. Nevertheless, little is known about nicotine dependence in tobacco smokers who use waterpipes.

OBJECTIVE

To assess evidence of dependence among non-cigarette smoking waterpipe smokers in Egypt.

METHODS

A total of 154 male exclusive current waterpipe smokers were enrolled for the present study. We adapted the Fagerström test for nicotine dependence and the Reasons for Smoking (RFS) scales and related these to smoking behavior.

RESULTS

The mean age of the subjects was 47 ± 14 years, the mean age at smoking initiation was 22 ± 9 years, and average daily consumption was 4 ± 8 hagars (tobacco units). The time to the first smoke of the day (P < 0.001), smoking even when ill (P = 0.003), time to tobacco craving (P < 0.001), and hating to give up the first smoke of the day (P = 0.033) were each significantly associated with the number of hagars smoked per day. The RFS subscales of addictive smoking, smoking to relieve negative affect, and smoking for stimulation were also associated with these variables.

CONCLUSION

The overall findings suggest that waterpipe smokers exhibit many of the same features of nicotine dependency attributed to cigarette smokers.

Reproducibility of liver stiffness measurements in hepatitis C virus (HCV)-infected patients in Egypt

Elastometry has demonstrated good accuracy, but little is known about its reproducibility. The aim of this study was to assess the intra- and inter-operator reproducibility of liver stiffness measurement among hepatitis C virus (HCV)-infected patients in Egypt. The study was conducted among HCV-infected patients referred for treatment evaluation in two hepatitis treatment centres of Cairo. Two operators took liver stiffness measurement two times per patient the same day. Intra- and inter-reproducibility were estimated by different methods: Bland and Altman graphics, variation coefficient, intraclass correlation coefficient and Kappa coefficient; 7.1 kPa was used as the threshold of significant (≥F2) fibrosis whenever needed. Fifty-eight patients were included in the study, and 216 measurements were taken. Failure rate was 7% and associated with overweight. For a value of 7.1 kPa, the inter-operator 95% limits of agreement were estimated at ±2.88 kPa. Intra- and inter-operator coefficients of variation ranged between 11% and 15%, intraclass correlation coefficients [95% confidence interval] between 0.94 [0.86-0.97] and 0.97 [0.95-0.99], and Kappa coefficients between 0.65 [0.44-0.88] and 0.92 [0.81-1.00]. The reliability of liver stiffness measurement is questionable when considering the decision to initiate antiviral therapy because of the percentage of discordance between measurements is notable, especially in the intermediate fibrosis stages.

HCV iatrogenic and intrafamilial transmission in Greater Cairo, Egypt

OBJECTIVES

To document hepatitis C virus (HCV) intrafamilial transmission and assess its relative importance in comparison to other current modes of transmission in the country with the largest HCV epidemic in the world. HCV intrafamilial transmission was defined as HCV transmission among relatives living in the same household.

DESIGN

Case-control study. Cases were adult patients with acute hepatitis C diagnosed in two 'fever hospitals' of Cairo. Controls were adult patients with acute hepatitis A diagnosed in the same two hospitals, and family members of cases. All consenting household members of cases provided blood for HCV serological and RNA testing. Homology of viral sequences (NS5b region) within households was used to ascertain HCV intrafamilial transmission. Exposures at risk for HCV during the 1-6 months previous to onset of symptoms were assessed in all cases and controls.

RESULTS

From April 2002 to June 2007, 100 cases with acute hepatitis C, and 678 controls (416 household members and 262 patients with acute hepatitis A) were recruited in the study. Factors independently associated with HCV infection and their attributable fractions (AFs) were the following: having had a catheter (OR=5.0, 95% CI=1.4 to 17.8; AF=6.7%), an intravenous perfusion (OR=5.8, 95% CI=2.5 to 13.3; AF=20.1%), stitches (OR=2.0, 95% CI=1.3 to 6.6; AF=10.7%), gum treatment (OR=3.7, 95% CI=1.1 to 11.9; AF=3.8%) and being illiterate (OR=2.4, 95% CI=1.4 to 4.4). Of the 100 cases, 18 had viraemic HCV-infected household members. Three long-married (>15&emsp14;years) couples were infected with virtually identical sequences and none of the three index patients reported any exposure at risk, suggesting HCV intra-familial transmission.

CONCLUSION

While three new HCV infections out of 100 could be linked to intra-familial transmission, parenteral iatrogenic transmission (dental care included) was accountable for 34.6% of these new infections. Thus, the relative contribution of intrafamilial transmission to HCV spread seems to be limited.

Dissection of familial correlations in hepatitis C virus (HCV) seroprevalence suggests intrafamilial viral transmission and genetic predisposition to infection

OBJECTIVE

Unsafe injections and transfusions used during treatments are considered to be responsible for many cases of transmission of hepatitis C virus (HCV) in developing countries, but cannot account for a substantial proportion of present infections. The aim of the present work was to investigate familial clustering of HCV infection in a population living in a highly endemic area.

DESIGN, SETTING AND PARTICIPANTS

A large seroepidemiological survey was conducted on 3994 subjects (age range, 2-88 years) from 475 familial clusters in an Egyptian rural area. Epidemiological methods appropriate for the analysis of correlated data were used to estimate risk factors and familial dependences for HCV infection. A phylogenetic analysis was conducted to investigate HCV strain similarities within and among families.

MAIN OUTCOME MEASURES

HCV familial correlations adjusted for known risk factors, similarities between viral strains.

RESULTS

Overall HCV seroprevalence was 12.3%, increasing with age. After adjustment for relevant risk factors, highly significant intrafamilial resemblances in HCV seroprevalence were obtained between father-offspring (odds ratio (OR) = 3.4 (95% confidence interval (CI), 1.8 to 6.2)), mother-offspring (OR = 3.8 (95% CI, 2.5 to 5.8)), and sibling-sibling (OR = 9.3 (95% CI, 4.9 to 17.6)), while a weaker dependence between spouses (OR = 2.2 (95% CI, 1.3 to 3.7)) was observed. Phylogenetic analysis showed greater HCV strain similarity between family members than between unrelated subjects, indicating that correlations can be explained, in part, by familial sources of virus transmission. In addition, refined dissection of correlations between first-degree relatives supported the role of host genes predisposing to HCV infection.

CONCLUSIONS

Current HCV infection in endemic countries has a strong familial component explained, at least partly, by specific modes of intrafamilial viral transmission and by genetic predisposition to infection.

Metabolic and cardiovascular risk profiles and hepatitis C virus infection in rural Egypt

BACKGROUND AND AIMS

To investigate the relationship between lipid profiles and diabetes with past and chronic hepatitis C virus (HCV) infection among village residents of Egypt.

PATIENTS AND METHODS

Fasting lipids and glucose profiles were compared among adults never infected with HCV (negative HCV antibodies), infected in the past (positive HCV antibodies and negative HCV RNA) and chronically infected (positive HCV antibodies and HCV RNA).

RESULTS

Of the 765 participants, 456 (59.6%) were female, and median age was 40 (range 25-88) years. Chronic HCV infection was present in 113 (14.8%) and past infection in 67 (8.8%). After adjustment for age and sex, participants with chronic HCV infection had lower plasma low density lipoproteins (LDL) cholesterol and triglyceride levels compared with those never infected (age and sex adjusted differences (95% CI) were -19.0 (-26.3 to -11.7) mg/dl and -26.2 (-39.0 to -13.3) mg/dl, respectively). In contrast, participants with cleared HCV infection had higher triglyceride levels compared with those never infected (age and sex adjusted difference (95% CI) was +16.0 (0.03 to 31.9) mg/dl). In multivariate analysis, participants with chronic HCV infection were more likely to have diabetes (OR 3.05, 95% CI 1.19 to 7.81) compared with those never infected, independent of LDL cholesterol levels.

CONCLUSION

In conclusion, this community based study has shown that in a single population, chronic HCV infection is associated with glucose intolerance and, despite that, a favourable lipid pattern. An intriguing finding was the high triglyceride levels observed among participants with past infection, suggesting that elevated triglycerides at the time of acute infection may facilitate viral clearance.

Higher clearance of hepatitis C virus infection in females compared with males

BACKGROUND AND AIMS

According to the literature, 14-46% of subjects clear hepatitis C virus (HCV) from blood after infection. Controversy exists about sex differences in HCV clearance rates.

PATIENTS AND METHODS

We compared HCV clearance in males and females using data from a large population based study on HCV infection in Egypt. Definitions used in the paper were: cleared HCV infection (positive HCV antibody and negative HCV RNA test results) and chronic HCV infection (positive HCV antibody and positive HCV RNA test results). The study sample included 4720 village residents aged 18-65 years recruited through home based visits (n = 2425) or voluntary screening (n = 2295).

RESULTS

Overall, HCV antibody prevalence was 910/4720 (19.3% (95% confidence interval 18.2-20.4)). Of those with HCV antibodies (n = 910), 61.5% had chronic HCV infection. Compared with males, females were more likely to have cleared the virus (44.6% v 33.7%, respectively; p = 0.001). Control for age, schistosomiasis history, iatrogenic exposures, and sexual exposure to HCV did not alter the positive association between female sex and viral clearance.

CONCLUSION

This study provides strong evidence in favour of a higher HCV clearance rate in females compared with males.

Skin rash and good performance status predict improved survival with gefitinib in patients with advanced non-small cell lung cancer

BACKGROUND

Gefitinib (Iressa) is active as a single agent in the treatment of select patients with recurrent non-small cell lung cancer (NSCLC). The clinical characteristics of patients treated with gefitinib on an Expanded Access Program (EAP) at our institution identified predictive variables associated with better outcome.

PATIENTS AND METHODS

Patients (n=199) with advanced NSCLC were treated with gefitinib (250 mg) upon progression with chemotherapy. Baseline patient characteristics were: median age, 69 years; males, 57%; adenocarcinoma, 56%.

RESULTS

Partial responses were noted in two patients (1%) and disease stabilization in 66 (35%) patients. The median survival (MS) was 5.9 months [95% confidence interval (CI) 4.1-7.1] and median time to progression was 3 months (95% CI 2.0-3.0). The predictive factors analyzed were gender, skin rash, diarrhea, tumor histology and performance status (PS). Patients who developed skin rash (any grade) had MS of 10.8 months versus 4.0 months for those without rash (P <0.0001, log rank test). Patients with PS 0, 1 and 2 had MS of 8.4, 6.2 and 2.8 months, respectively (P <0.0002). The other factors did not impact survival.

CONCLUSIONS

Occurrence of skin rash and baseline PS of 0/1 were associated with improved survival with gefitinib for recurrent NSCLC patients at our institution.

Hepatitis C virus infection in a community in the Nile Delta: risk factors for seropositivity

The purpose of this study was to identify risk factors for hepatitis C virus (HCV) infection in a rural village in the Nile Delta with a high prevalence of antibodies to HCV (anti-HCV). One half of the village households were systematically selected, tested for anti-HCV, and interviewed: 973 of 3,999 (24.3%) subjects were anti-HCV-positive (reflecting prior HCV infection but not necessarily current liver disease), with nearly equal prevalence among males and females. Anti-HCV prevalence increased sharply with age among both males and females, from 9.3% in those 20 years of age and younger to >50% in those older than 35, suggesting a cohort effect with reduced transmission in recent years. Multivariate regression was used to estimate independent effects of risk factors on seropositivity. Among those over 20 years of age, the following risk factors were significantly associated with seropositivity: age (P <.001); male gender (odds ratio [OR] = 2.5, 95% CI = 1.3-4.7); marriage (OR = 4.1, 2.4-6.9); anti-schistosomiasis injection treatment (OR = 2.0, 1.3-2.9); blood transfusion (OR = 1.8, 1.1-2.9), invasive medical procedure (surgery, catheterization, endoscopy, and/or dialysis) (OR = 1.5, 1.1-1.9); receipt of injections from "informal" health care provider (OR = 1.3, 1.0-1.6); and cesarean section or abortion (OR = 1.4, 1.0-1.9). Exposures not significantly related to anti-HCV positivity in adults included: history of, or active infection with, Schistosoma mansoni, sutures or abscess drainage, goza smoking in a group, and shaving by community barbers. Among those 20 years old or younger, no risk factors were clearly associated with anti-HCV positivity; however, circumcision for boys by informal health care providers was marginally associated with anti-HCV (OR = 1.7, 1.0-3.0). Prevention programs focused primarily on culturally influenced risks in rural Egyptian communities are being implemented and evaluated.

Hepatitis C virus (HCV) infection in a community in the Nile Delta: population description and HCV prevalence

This report describes a cross-sectional survey of the prevalence of antibodies to hepatitis C virus (anti-HCV) in a rural Egyptian community in the Nile Delta. One half of the village households were systematically selected and examined by questionnaire and testing sera for anti-HCV and HCV RNA. Blood samples were obtained from 3, 888 (75.4%) of 5,156 residents >/=5 years of age; an additional 111 samples were obtained from children younger than 5 years. Overall, 973 (24.3%) of 3,999 residents were anti-HCV-positive, and the age- and gender-adjusted seroprevalence was 23.7%. Anti-HCV prevalence increased sharply with age, from 9.3% in those 20 years of age and younger to >50% in those older than 35 years. Currently or previously married individuals were more likely to be seropositive than those never married, controlling for age (Mantel-Haenszel risk ratio = 1.8; 95% CI: 1.3, 2.6). Of the 905 anti-HCV-positive samples tested, 65% were also positive for HCV RNA. Active schistosomal infection was not associated with anti-HCV status; however, history of antischistosomal injection therapy (reported by 19% of anti-HCV positives) was a risk for anti-HCV (age-adjusted risk ratio = 1.3; 95% CI: 1.2, 1.5). This study, the largest community-based survey to date, supports earlier reports of high levels of anti-HCV among adults in rural areas of Egypt, although many of those who are seropositive will not have active liver disease. The large reservoir of HCV infection in the community provides an opportunity to investigate risk factors for transmission, the natural history of infection and effectiveness of preventive methodologies, and raises concern about the prospect of an increasing incidence of chronic liver disease in the coming decades.

The role of parenteral antischistosomal therapy in the spread of hepatitis C virus in Egypt

BACKGROUND

The population of Egypt has a heavy burden of liver disease, mostly due to chronic infection with hepatitis C virus (HCV). Overall prevalence of antibody to HCV in the general population is around 15-20%. The risk factor for HCV transmission that specifically sets Egypt apart from other countries is a personal history of parenteral antischistosomal therapy (PAT). A review of the Egyptian PAT mass-treatment campaigns, discontinued only in the 1980s, show a very high potential for transmission of blood-borne pathogens. We examine the relative importance of PAT in the spread of HCV in Egypt.

METHODS

The degree of exposure to PAT by cohort was estimated from 1961-86 Ministry of Health data. A cohort-specific exposure index for PAT was calculated and compared with cohort-specific HCV prevalence rates in four regions.

FINDINGS

HCV prevalence was calculated for 8499 Egyptians aged 10-50 years. A significant association between seroprevalence of antibodies to HCV and the exposure index (1.31 [95% CI 1.08-1.59]; p=0.007) was identified across four different regions. In all regions cohort-specific HCV prevalence was lowest in children and young adults than in older cohorts. These lower prevalence rates coincided with the gradual and final replacement of PAT with oral antischistosomal drugs at different points in time in the four regions.

INTERPRETATION

The data suggest that PAT had a major role in the spread of HCV throughout Egypt. This intensive transmission established a large reservoir of chronic HCV infection, responsible for the high prevalence of HCV infection and current high rates of transmission. Egypt's mass campaigns of PAT may represent the world's largest iatrogenic transmission of blood-borne pathogens.

Effect of long-term ovariectomy and estrogen replacement on the expression of estrogen receptor gene in female rats

OBJECTIVE

Estrogen exerts a wide variety of actions involving many target tissues. We studied the effects of long-term ovariectomy (OVX) and OVX with 17beta-estradiol treatment (OVXE2) on the level of estrogen receptor (ER) gene expression in target tissues of female rats.

DESIGN

Three groups of Sprague-Dawley female rats were utilized in this study: sham operated (SO), OVX and OVXE2.

METHODS

SO and OVX were performed 2 weeks before starting the 17beta-estradiol treatment. All groups were maintained on liquid diet for 12 weeks from the time of estradiol treatment. Total RNA was prepared from the tissues of the rats and relative quantitative reverse transcription PCR was utilized to compare the ER alpha-subtype (ERalpha) mRNA level in the three groups for each target tissue.

RESULTS

Following long-term OVX, the levels of ERalpha expression showed a significant increase in the uterus, kidney and cerebral cortex and no significant change in the liver, cerebellum, brainstem, heart and thoracic and abdominal aorta compared with their SO levels. On the other hand, a 12-week treatment of OVX rats with 17beta-estradiol restored the previously upregulated ERalpha mRNA to near SO levels except for the liver where the 17beta-estradiol treatment resulted in a significant increase in the ERalpha mRNA level compared with that in SO rats.

CONCLUSIONS

We conclude that the regulation of ERs by its ligand is tissue specific.

Estrogen enhancement of baroreflex sensitivity is centrally mediated

We have recently shown that estrogen enhances baroreceptor control of reflex bradycardia in conscious rats. The present study replicated this finding in pentobarbital sodium-anesthetized rats, and the study was extended to investigate whether this effect of estrogen is centrally or peripherally mediated. Hemodynamic responses to electrical stimulation of the central end of the aortic depressor or the vagal efferent nerve were evaluated in pentobarbital sodium-anesthetized sham-operated (SO), ovariectomized (OVX), and OVX estradiol-treated Sprague-Dawley rats. Phenylephrine (1-16 microgram/kg iv) elicited dose-dependent pressor and bradycardic responses. Regression analysis of the baroreflex curves, relating changes in mean arterial pressure and heart rate, revealed a significantly smaller baroreflex sensitivity in OVX compared with SO anesthetized rats (-0.54 +/- 0.05 and -0.91 +/- 0.12 beats. min-1. mmHg-1, respectively; P < 0.05). Treatment of OVX rats with 17beta-estradiol (E2, 50 microgram. kg-1. day-1 for 2 days subcutaneously) significantly enhanced baroreflex sensitivity to a level similar to that of SO rats (P < 0.05). The enhancing effect of E2 on the baroreflex-mediated bradycardia, observed in conscious and anesthetized rats, seems to be selective because the baroreflex-mediated tachycardic responses measured in a separate group of conscious rats were not altered by ovariectomy or E2 administration. Electrical stimulation of the aortic nerve elicited frequency-dependent depressor and bradycardic responses that were significantly smaller in OVX compared with SO values (P < 0.05). Treatment of OVX rats with E2 restored the hemodynamic responses to aortic stimulation to near SO levels. On the other hand, hemodynamic responses to vagal stimulation were not affected by OVX or treatment with E2. These findings suggest that enhancement of reflex bradycardia by estrogen is centrally mediated and involves interaction with central projections of the aortic nerve.

Structure and upstream region characterization of the human gene encoding rod photoreceptor cGMP phosphodiesterase alpha-subunit

Rod photoreceptor cGMP phosphodiesterase (PDE6) is a three-subunit (a, b, g2) enzyme that functions to reduce intracellular cytoplasmic cGMP levels, an integral feature of the phototransduction cascade of vision. To allow assessment of the potential for defects in the gene encoding the alpha-subunit (PDE6A) to cause visual dysfunction, and to begin to dissect the basis for photoreceptor-specific expression of this gene, we have characterized the structural gene and upstream region. The human PDE6A gene consists of 22 exons spanning about 60 kb with the intron/exon junctions highly conserved in comparison to the mouse and human PDE6B genes. Using ribonuclease protection and primer extension assays, a predominant transcription start point (tsp) was identified 120 bp upstream of the initiator ATG. To begin functional analysis of the PDE6A promoter, approx 4 kb of sequence were determined upstream of the tsp. Comparison of this upstream sequence with an approximately 500 bp sequence upstream of the mouse Pde6a gene revealed five distinct segments of identity all within 100 bp upstream of the human PDE6A tsp. A TATA box adjacent to a photoreceptor-specific RET1-like binding site, an SP1 site, and two novel putative cis-element sequences were found. A consensus initiator element sequence is present at the tsp. Additionally, within a 2.5-kb segment beginning 900 bp upstream of the tsp two Alu, a MIR, an L1, and two MER repetitive elements were found. Electrophoretic mobility shift assays generate a retina-specific bandshift using a 322-bp fragment containing the putative promoter region or a multimer of the RET1-like site. DNA footprinting assays revealed footprints over the primary transcription startpoint and the RET1-like and TATA box regions. These results indicate that a 220-bp segment of the PDE6A gene upstream region is important for tissue-specific expression.

13th meeting of the Scientific Group on Methodologies for the Safety Evaluation of Chemicals (SGOMSEC): alternative testing methodologies and conceptual issues

Substantial world-wide resources are being committed to develop improved toxicological testing methods that will contribute to better protection of human health and the environment. The development of new methods is intrinsically driven by new knowledge emanating from fundamental research in toxicology, carcinogenesis, molecular biology, biochemistry, computer sciences, and a host of other disciplines. Critical evaluations and strong scientific consensus are essential to facilitate adoption of alternative methods for use in the safety assessment of drugs, chemicals, and other environmental factors. Recommendations to hasten the development of new alternative methods included increasing emphasis on the development of mechanism-based methods, increasing fundamental toxicological research, increasing training on the use of alternative methods, integrating accepted alternative methods into toxicity assessment, internationally harmonizating chemical toxicity classification schemes, and increasing international cooperation to develop, validate, and gain acceptance of alternative methods.

Multivariate analysis of DNA ploidy, p53, c-erbB-2 proteins, EGFR, and steroid hormone receptors for short-term prognosis in breast cancer

BACKGROUND

Several molecular-genetic alterations in breast cancer, including aneuploidy, aberrant expression of p53, c-erbB-2, and EGFR have been associated with poor prognosis in breast cancer particularly in lymph node negative patients. To determine the importance of molecular-genetic factors relative to more traditional surgical-pathologic prognostic factors, a multivariate analysis was performed particularly in lymph node positive breast cancer cases.

METHODS

One hundred fresh samples of primary breast carcinoma have been studied with flow cytometry for DNA ploidy. On the same specimens steroid hormone receptors (ER and PR) were measured in cytosol fraction using Abbott ELIZA assays, c-erbB-2 and EGFR were determined in the tissue homogenate and mutant p53 protein in the nuclear fraction by Oncogene Science ELISA procedures. In addition, information regarding surgical-pathologic features of the tumor was obtained. Multivariate analysis using Cox's proportional hazards model was done to identify variables predictive of poor prognosis.

RESULTS

With univariate analysis, tumor size, lymphnode number, p53, c-erbB-2 were predictive of poor short term prognosis. In the multivariate analysis, only c-erbB-2 (P = 0.001) and p53 (P = 0.05) were significant. Subgroup analysis by nodal status yielded significant association of c-erbB-2 (P = 0.001) and p53 (P = 0.04) with lymph node positive breast cancer.

CONCLUSIONS

Among molecular-genetic prognostic factors, c-erbB-2 was the most strongly predictive of poor short term prognosis followed by p53 in lymph node positive breast cancer.

Multivariate analysis of DNA ploidy, p53, c-erbB-2 proteins, EGFR, and steroid hormone receptors for prediction of poor short term prognosis in breast cancer

BACKGROUND

Several molecular-genetic alterations in breast cancer, including aneuploidy, aberrant expression of p53, c-erbB-2 and EGFR, have been associated with poor prognosis in breast cancer patients particularly those who are lymph node negative. To determine the importance of molecular-genetic factors relative to more traditional surgical-pathologic prognostic factors, multivariate analysis was performed on lymph node positive breast cancer cases.

METHODS

One hundred fresh samples of primary breast carcinoma were studied with flow cytometry for DNA ploidy. On the same specimens steroid hormone receptors (ER and PR) were measured in the cytosol fraction using Abbott ELIZA assays, c-erbB-2 and EGFR were determined in the membrane fraction and mutant p53 protein in the nuclear fraction by Oncogene Science ELISA procedures. In addition, information regarding surgical-pathologic features of the tumor was obtained. Multivariate analysis using Cox's proportional hazards model was done to identify variables predictive of poor prognosis.

RESULTS

Using univariate analysis, tumor size, lymph node number, p53, c-erbB-2 were predictive of poor short term prognosis. By multivariate analysis, only c-erbB-2 (P = 0.001) and p53 (P = 0.05) were significant. Subsgroup analysis by nodal status yields a significant association of c-erbB-2 (P = 0.001) and p53 (P = 0.04) with lymph node positive breast cancer.

CONCLUSIONS

Among molecular-genetic prognostic factors, c-erbB-2 was the most strongly predictive of poor short term prognosis followed by p53 in lymph node positive breast cancer.

A prospective study: prediction of the first variceal haemorrhage in schistosomal and non schistosomal liver disease

A prospective study was conducted on liver disease patients without previous history of bleeding (haematemesis and/or melena) to identify those at highest risk of bleeding. A hundred and twenty non-alcoholic patients (96 males and 24 females), ages ranging from 30 to 60 years were studied. Patients were followed for up to two years or to time of bleeding (mean 18 +/- 7.3 months), during which 34 (28.3%) patients bled. Schistosomal patients showed less incidence of bleeding (12.1%, p < 0.05) than those with mixed aetiology (Schistosoma and cirrhosis 23.5%, and chronic active hepatitis and schistosoma 44.4%). The presence of positive viral markers (either HCV antibodies or HBsAg) was associated with a higher percent of bleeding during the follow-up period (43.2% and 45.4%, respectively), than those negative for these markers (21.7%, 24.4%, respectively). Univariate analysis showed the following significant risk factors associated with bleeding: modified child classification, reduced platelet count, endoscopic findings of cherry red spots, gastric varices and increased grade of oesophageal varices. Multivariate analysis revealed that the risk of bleeding was significantly related to the presence of cherry red spots, the presence of gastric varices, grade of oesophageal varices and the patient's prothrombin time. In conclusion, bleeding from oesophageal varices is a frequent and serious event in patients with chronic liver disease. The risk of variceal bleeding from liver disease with mixed aetiology (schistosomiasis associated with viral hepatitis HBV or HCV) was found to be significantly higher than that with schistosomal aetiology alone. The endoscopic findings of cherry red spots, gastric varices, increased grade of oesophageal varices and to a lesser extent the prothrombin time were found to be high risk factors. Patients having those risk factors should be considered for prophylactic measures.

Viral hepatitis C infection among Egyptians the magnitude of the problem: epidemiological and laboratory approach

This study examines the relative importance of risk factors for viral hepatitis C infection and estimates the magnitude of HCV problem among Egyptians. It is a continuation of a recently performed cross-sectional study conducted on more than 5000 Egyptians. Serum samples (1945) were analyzed for liver enzymes (SGPT and SGOT) to evaluate the status of liver affection. One hundred and sixty nine samples (103 confirmed HCV seropositives and 66 seronegative) were analyzed for PCR HCV RNA to estimate the frequency of HCV viraemia among those individuals. Rates for HCV seropositivity by ELISA test in mass screening were corrected using predictive value of a positive test at prevalence between 5-50%. Attributable risk and population attributable risk estimates were calculated for those significant factors in logistic regression analysis. Overall number of HCV infected individuals was estimated for age groups of 15-65 years and the numbers of HCV related liver complications were estimated. HCV PCR RNA was positive for 50% of ELISA-seropositive samples and for 13.8% of the seronegative samples. However, only 5% of those individuals with HCV seropositivity and 3.7% of those with PCR RNA positivity Showed SGPT serum levels above 1.5 normal. The overall age, sex and urban/rural adjusted rate of true HCV seropositivity is estimated to be 15.6% among working Egyptians between 15-65 years. Attributable risk due to injections for the treatment of bilharziasis is estimated to be 47% (95% CL = 38%-55%) among exposed males. Blood transfusion was estimated to be responsible for 87% (95% CL = 57%-96%) of cases among previously transfused females. Population attributable risk for injections for treatment of bilharziasis among working urban and rural males is estimated to be 15% and 11% respectively. Blood transfusion and sharing contaminated needles contributed by 24% of cases (for each) among working urban females. Previous hospitalization contributed by 36% of cases among working rural females and by 10% among working urban males. As for the national estimate of cases of HCV seropositivity we estimated more than 5 million individuals with an expected number of chronic hepatitis of varying degrees of 3.5 millions. HCV viraemia with high probability for transmission is present in more than 50% of those individuals and liver cirrhosis cases expected to develop within an average of 20 years of infection are in the range of 350-700 thousand cases. The major proportions of population attributable risk are due to other undefined risk factors associated with age, male sex, living in rural areas and in lower and upper Egypt. Further research is needed to elucidate those factors prevailing in these areas, associated with increased risk of HCV infection.

Study of the risk factors for viral hepatitis C infection among Egyptians applying for work abroad

The aim of this study was to identify the risk factors for viral hepatitis C infection among Egyptians. A cross-sectional study with case-control analysis was conducted including 5071 Egyptians applying to the Ministry of Health Laboratories for certification of freedom from viral hepatitis (B and C) to work abroad. A questionnaire designed to cover the most important known and suspected risk factors was filled out by physicians interviewers before blood drawing and after proper orientation of the purpose of the study. The overall seropositivity among the whole sample for HCV was 31.5% and was significantly lower among females (13.2%) than among males (34%). A consistent increase of seropositivity for HCV antibodies with age (in males and females and in urban and rural areas) was observed with a peak level of 54.9% in all individuals for the age group 45-49 years (significant trend p < 0.0001). A significant increase of seropositivity (p < 0.005) above 25 years of age (35.7%) than below this age 12.8%) was observed on examination of HCV distribution in 5-year age group. Married individuals have a significant higher seropositivity for HCV than non-married (38.2% and 20.9% respectively OR = 2.3, 95% CL 2.1-2.7). Individuals living in rural areas had significantly more HCV seropositivity than those living in urban areas (OR = 1.7, 95% CL 1.5-2.0). Also, individuals living in Cairo and seashore governorates had significantly lower seropositivity (14.7% and 12.7% respectively) than those living in governorates in upper or lower Egypt (29.4% and 36.3% respectively). Medical procedures risk factors identified to be associated with significant higher HCV seropositivity included: past history of injections for bilharziasis, use of common syringes, dental extraction, injections for urography, blood transfusions and previous hospitalizations. Multivariate logistic analysis revealed that only age, male sex, marriage, rural residence, living in upper and lower Egypt, injections for bilharziasis and urography were significant in the final equation for the whole group. Blood transfusion was significant in the final regression analysis among females in urban living and hospitalization was significant among males in urban living and females in rural living. Further research is needed to elucidate those factors prevailing in rural areas and in upper and lower Egypt associated with increased risk for HCV infection.

Multivariate analysis of DNA ploidy, steroid hormone receptors, and CA 125 as prognostic factors in ovarian carcinoma: a prospective study

The prognosis in ovarian cancer patients remains poor, and there is a need to identify patients who are less likely to respond to treatment. In a prospective study of patients with ovarian carcinoma treated by a standard protocol, variables such as age, tumor type, International Federation of Gynecology and Obstetrics stage, histologic grade, results from flow cytometry, receptors for estrogen (ER) and progesterone (PR), and serum CA 125 were correlated to relapse and survival. Univariate analysis revealed that stage, histologic grade, DNA ploidy, ER, PR, and CA 125 were of significant association to survival, but only stage, DNA ploidy, PR, and CA 125 were found to be of significant value to relapse. Multivariate analysis identified DNA ploidy as an independent prognostic variable for both relapse and survival.

The leucine zippers of c-fos and c-jun for progesterone receptor dimerization: A-dominance in the A/B heterodimer

Human progesterone receptors (hPR) exist as two isoforms: 120 kDa B-receptors (hPRB) and N-terminally truncated 94 kDa A-receptors (hPRA). When transfected separately, each isoform exhibits different transcriptional properties that are ligand- and promoter-specific. In human target tissues, both receptor isoforms are present, so that a mixture of three dimeric species, A/A, A/B, and B/B, bind to DNA at progesterone response elements (PRE), and regulate transcription. To study the transcriptional phenotype of pure A/B heterodimers uncontaminated by A/A or B/B homodimers, we exploited the property of the leucine zipper (zip) domains of fos and jun, to form pure heterodimers. Chimeric constructs were made linking the zip of either c-fos or c-jun to the C-terminus of hPRB or hPRA (hPR-zip) to produce A-fos, B-fos, A-jun or B-jun. To determine whether the A- or B-isoform is functionally dominant in the A/B heterodimer, cells expressing hPR-zip chimeras were treated with the progestin antagonist RU486, which produces opposite transcriptional effects with the two isoforms. Gel mobility shift and immune co-precipitation assays show that in the presence of RU486 only pure heterodimers form between A-fos/B-jun or A-jun/B-fos, and bind DNA at PREs. Thus, in these pairs, interactions between the extrinsic fos/jun zipper domains override interactions between the intrinsic hPR dimerization domains. We find that under these conditions, antagonist-occupied B-zip homodimers stimulate transcription, while antagonist-occupied A-zip homodimers are inhibitory, and that pure A/B zip heterodimers have the inhibitory transcriptional phenotype of the A-zip homodimers. We conclude that, in pure heterodimers, A-receptors are dominant negative inhibitors of B-receptors. Additionally, the pure PR-zip heterodimers, unlike wild-type receptors, bind a PRE in the absence of hormone but do not activate transcription. Thus, PR dimerization and PRE binding are necessary but, without hormone, not sufficient to activate transcription.

Antagonist-occupied human progesterone B-receptors activate transcription without binding to progesterone response elements and are dominantly inhibited by A-receptors

When antagonist-occupied steroid receptors have agonist-like effects, the clinical consequences are grave. We present evidence that human progesterone B-receptors (hPRB) when occupied by progesterone antagonists, inappropriately activate transcription by an unusual mechanism that does not require the canonical progesterone response element (PRE). In HeLa cells cotransfected with a PRE-tk-chloramphenicol acetyltransferase reporter and a hPRB expression vector, strong transcription is seen not only when receptors are activated by the agonist R5020, but also in the presence of the three antiprogestins, RU486, ZK112993, and ZK98299. Human PRB occupied by ZK98299 do not bind to a PRE, suggesting that the transcriptional stimulation is independent of DNA binding. Indeed, a tk-chloramphenicol acetyltransferase promoter-reporter lacking the PRE loses transcriptional activation by the agonist, but retains transactivation by the three antagonists. The PRE-independent antagonist-induced transcription requires that hPRB have an intact DNA-binding domain, but hPR target gene specificity is not required, because a hPRB mutant that binds an estrogen response element still activates transcription. It appears that antagonist-occupied hPR activate transcription without binding to a PRE, perhaps by interacting with tethering proteins instead. Even a gene that is not a normal progesterone target could be aberrantly activated. Human cells contain equimolar amounts of hPRB and the N-terminally truncated natural isotype, hPRA. Unlike hPRB, hPRA are not transcriptionally activated by progesterone antagonists. We, therefore, tested the effects of antagonists when the two receptor isotypes are coexpressed and found that A-receptors can annul the inappropriate transcription by B-receptors. Thus, when both receptor forms are present, the hPRA phenotype is dominant. Moreover, pure hPRB/hPRA heterodimers, produced by fos/jun leucine zipper domain-hPR chimeras, also have the inactive transcriptional phenotype of hPRA. Our studies suggest not only that the two hPR isotypes are functionally quite different, but also that some of the agonist-like transcriptional effects of antagonist-occupied B-receptors proceed through novel mechanisms.

Kinetics of methyl mercury in blood and brain during chronic exposure in the monkey Macaca fascicularis

The disposition parameters derived from a compartmental model kinetic analysis of blood Hg levels in nonpregnant, adult female Macaca fascicularis given daily doses of MeHg did not vary with either dosage level (50, 70 or 90 micrograms MeHg/kg b.wt.day) or duration of exposure (up to 507 day). In contrast, blood clearance of Hg in pregnant females was dose-dependent; it being higher at the 90 micrograms MeHg/kg b.wt.day than at the lower dosage levels. Hg levels in the brain of adult fascicularis relative to blood Hg also increased at the highest level of exposure. Blood Hg half-life in neonate fascicularis was similar to half-life in their mothers (adults). Finally, the regional distribution of mercury in the brains of adult and neonate fascicularis exposed to low and intermediate levels of MeHg resembles the reported distribution of mercury in the brains of adult and neonate humans environmentally exposed to MeHg. Consequently, M. fascicularis may be an especially appropriate animal model for studying the neurotoxic mechanisms of chronic methyl mercury exposure.

Methylmercury effects on reproduction and offspring size at birth

This article describes a study of the toxic, reproductive, and developmental effects of chronic methylmercury (MeHg) exposure in Macaca fascicularis monkeys. Adult and infant monkeys were studied using procedures to assess maternal and newborn blood Hg concentrations, menstrual cyclicity, conception rate, reproductive outcome, maternal toxicity, and offspring size at birth. Maternal intakes of 0, 50, 70, or 90 micrograms/kg/d MeHg hydroxide were studied. Maternal blood Hg concentrations reached equilibrium by 10 weeks of exposure. The half-life of blood Hg for adult females ranged from 15 to 40 days (mean = d) and did not vary with dose. Maternal MeHg exposure did not affect the length of the menstrual cycle or the conception rate. Maternal MeHg exposure did significantly reduce the number of viable deliveries at blood Hg concentrations above 1.5 ppm. Maternal blood Hg concentrations at delivery were significantly lower than newborn concentrations. No effect of maternal MeHg exposure on offspring size at birth was observed. Maternal toxicity was related to blood Hg concentrations above 2.0 ppm following approximately one year of exposure. Results indicate that MeHg exposure can affect reproductive outcome at levels that do not cause overt toxicity.

Effects of methyl mercury on testicular functions in Macaca fascicularis monkeys

These studies were performed to investigate the effects of MeHg on testicular function in Macaca fascicularis monkeys. In an in vivo study involving oral treatment of adult males Macaca fascicularis monkeys with MeHg for 20 weeks, changes in spermatozoal production, motility and morphology and in serum testosterone were followed before, during and after treatment. MeHg treatment significantly decreased % motile spermatozoa and scores for sperm speed and forward progression and increased % abnormal sperm tail forms, at sub-neurotoxic levels. The MeHg-induced increase in semen abnormalities was not accompanied by any significant changes in serum levels of testosterone. No consistent histological abnormalities were detected in testicular biopsies from the treated animals at the end of the treatment period. A good recovery pattern was observed for the MeHg effects on sperm motility while this was unclear for the effects on sperm morphology.

Effects of methyl mercury on sperm oxygen consumption

Oxygen consumption and percent motile spermatozoa were determined for semen samples from healthy male monkeys Macaca fascicularis. Methyl mercury was added to the samples, in the oxygen measurement chamber, at a concentration of 9 p.p.m. for 15 min. and then increased to 15 p.p.m. for 15-30 min. Oxygen consumption and percent motility were determined during each period. Methyl mercury addition resulted in decreased sperm motility, but we did not detect any inhibition in the rate of oxygen consumption accompanying the decreased motility. On the contrary, the rate of oxygen consumption increased at 15 p.p.m. within 15 min., while the sperm motility was close to zero. Antimycin inhibited the increased rate of oxygen consumption demonstrating the mitochondrial source of this increased rate. Oligomycin also inhibited the increased rate of oxygen consumption due to methyl mercury, thus excluding the possibility of uncoupling of mitochondrial oxidative phosphorylation. Interference with mitochondrial energy production does not seem to be the primary mechanism of methyl mercury-induced decreased spermatozoal motility. Methyl mercury interference with the dynein/microtubule sliding assembly now seems to us to be a more tenable hypothesis.

Laser light-scattering study of the toxic effects of methylmercury on sperm motility

An in vitro study was designed using the laser light-scattering technique to obtain further information on the dose-effect relationship of methylmercury on sperm motility. The technique provided a quantitative evaluation of sperm swimming speed. Semen samples were collected from normal male Macaca fascicularis monkeys by anal electroejaculation. Methylmercury was added to aliquots of sperm suspensions in BWW medium in doses of 10, 5, 2, and 1 ppm. After 3 hours, the relative speed was 35%, 59%, 69%, and 92% of the corresponding controls at doses of 10, 5, 2, and 1 ppm, respectively. The percentage of motile spermatozoa decreased significantly at 10 ppm. By microscopic observation abnormal motility was detected at 5 and 10 ppm, especially after 20 to 40 minutes. Head movement increased from side to side, and many spermatozoa developed coiled tails. The technique proved useful for defining the dose-effect relationship of methylmercury and sperm swimming speed.