Arieh Yaari

Hepatitis C virus infection in renal failure patients in the absence of anti-hepatitis C virus antibodies

The magnitude and clinical significance of Hepatitis C virus (HCV) infection in dialysis patients is controversial and underestimated. This study was conducted in order to evaluate the correlation between HCV replication and antibody response to HCV in dialysis patients. HCV infection in dialysis patients was evaluated over a period of 3 years and compared to HCV infection in Liver Clinic patients. Sera were collected from 310 dialysis patients and tested for anti‐HCV and HCV‐RNA. In addition, HCV genotype and HCV viral load were determined in HCV‐RNA‐positive sera. Anti‐HCV was detected in 43 (14%) of the dialysis patients. Of these, 37 (86%) were HCV‐RNA‐positive. Among the 267 HCV‐seronegative dialysis patients, 25 (9%) were found to be HCV‐RNA‐positive in more than one sample during the study. These patients were characterized by low viral load; at least two orders of magnitude lower than in the group of HCV‐seropositives. In contrast, in the Liver Clinic patients, HCV‐RNA was found exclusively in HCV‐seropositive patients. Comparison of the genotype pattern in the two groups did not reveal a difference.  Our results suggest that HCV infection in dialysis units may be underestimated due to cases of low viral load, depending on the method of RNA extraction and sensitivity of the test used. Low viral load might contribute to the lack of humoral immune response seen in some dialysis patients.

HCV antibodies in saliva and urine

Infection with hepatitis C virus (HCV) is usually established by detection of serum antibodies (anti‐HCV). This study was conducted in order to evaluate whether saliva and urine may substitute serum for anti‐HCV detection. Serum, saliva, and urine were obtained simultaneously from 141 patients with a variety of liver diseases and from 52 patients with autoimmune diseases (systemic lupus erythematosus n = 27 and rheumatoid arthritis n = 25). The cell free fraction of saliva and urine samples was tested for anti‐HCV using a modification of a serum anti‐HCV kit. Western blot analysis was used as a confirmation method. Of the patients with liver diseases, 73 were anti‐HCV‐seropositive. Salivary and urinary anti‐HCV could be detected in 66 (90%) and 36 (49%) of the anti‐HCV‐serpositive patients, respectively. The presence of anti‐HCV in saliva or urine was not related to the severity of liver disease. All the anti‐HCV‐seronegative liver patients were negative for salivary anti‐HCV and 22 (32%) had urinary anti‐HCV. The patients with autoimmune diseases were all anti‐HCV‐seronegative. None had detectable salivary anti‐HCV while 33 (63%) were positive for urinary anti‐HCV. Western Blot analysis confirmed the presence of anti‐HCV in all serum and saliva samples tested but only in 2/12 urine samples. The results suggest that saliva, but not urine, may serve as a substitute for serum for the determination of anti‐HCV positivity. J. Med. Virol. 55:24–27, 1998.

Hepatitis C virus infection and genotypes in Southern Israel and the Gaza strip

The Gaza Strip borders the southern part of Israel and Egypt. There is a remarkable difference in the prevalence of antibodies to hepatitis C virus (HCV) between Israel (0.5%) and Egypt (10%). A few thousand inhabitants cross the borders daily from the Gaza Strip to both countries. The objectives of this study were to investigate the prevalence of HCV infection in the Gaza Strip, an area that was not studied before, and to study HCV transmission in the Gaza Strip by characterizing the genotypes of HCV in Southern Israel and the Gaza Strip and comparing them with those found in Egypt. HCV prevalence in the Gaza Strip was found to be 2.2%, relatively higher than in Israel but lower than in Egypt. The most common genotypes found were type 1b in Southern Israel and type 4 in the Gaza Strip, corresponding to the most prevalent genotype in Egypt. Similarity between type 4 isolates from the Gaza Strip and Egypt was illustrated further by sequence analysis of the HCV 5′ noncoding region (NCR). J. Med. Virol. 56:230–233, 1998.

Coping styles and changes in humoural reaction during academic stress

The aim of the present study was to explore the relationship between coping styles and the changes in Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) specific salivary antibodies caused by academic stress. Fifty-four, first year, female students of nursing and physiotherapy completed pencil and paper questionnaires and concurrently donated saliva samples. The procedures included the ways of coping questionnaire, and scales of physical and psychological well-being. Data and saliva samples were collected 1 month after the beginning of the first semester (t1), during term examinations (t2 – t3), and 1 month into the second semester (t4). Statistically significant changes in the level of specific salivary EBV and HCMV antibodies were observed between the four study points, showing a decline in humoural functioning during examinations. Denial coping style seemed to moderate the modulation of HCMV IgG salivary antibodies; while emotion-focused coping was less effective and problem-focused coping was unrelated to changes in specific salivary antibodies.

Acute hemodynamic changes following hemorrhage and volume restitution, using a low viscosity plasma expander, in anesthetized portal hypertensive rats

BACKGROUND/AIM The aim of this study was to examine, in a portal hypertensive rat model, the hemodynamic changes following hemorrhage and volume restitution with blood and Haemaccel (a low viscosity, volume expander). METHODS Portal hypertension was induced by portal vein constriction. Under ketamine anesthesia, blood was withdrawn at a constant rate of 0.3 ml/min, for 15 min followed by 15 min of stabilization. The shed blood or Haemaccel was infused at the same rate and volume used for withdrawal. Hemodynamic measurements were performed using radioactive microspheres. Blood viscosity was measured with an Ostwald viscometer. Vascular hindrance was calculated as the resistance/viscosity ratio. RESULTS Twelve rats were studied in each group. During blood withdrawal, significant reductions in arterial pressure and portal pressure were observed. Volume replacement with blood was accompanied by increased mean arterial pressure and portal pressure to baseline. Arterial pressure following volume replacement with Haemaccel was lower and portal pressure was higher than baseline (128+/-16 and 17.1+/-3.9 vs 146+/-13 and 15.9+/-3.0 mmHg, respectively; p<0.05). Volume replacement with Haemaccel, compared to blood, was followed by increased cardiac output and portal venous inflow (39.3+/-11.6 and 4.4+/-1.5 vs 28.9+/-3 and 2.9+/-0.8 ml x min(-1) x 100 g bw(-1), respectively; p<0.05), decreased hematocrit and viscosity (29.3+/-3.8% and 2.8+/-1.3 vs 35.7+/-3.4% and 4.0+/-1.3, respectively; p<0.01) and decreased peripheral and splanchnic arteriolar resistance (3.6+/-1.4 and 29.2+/-14.0 vs 5.0+/-1.4 and 43.9+/-12.7 mmHg x ml(-1) x min x 100 g bw, respectively; p<0.05). There were no significant changes in vascular hindrance in any vascular beds between the two groups. CONCLUSION In this model, volume replacement with Haemaccel induced an increase in cardiac output and portal venous inflow, thus preventing the reduction in portal pressure which might be expected when viscosity is reduced.

Impact of pooling on accuracy of hepatitis B virus surface antigen screening of blood donations

Expenditure on screening blood donations in developing countries can be reduced by testing donations in pools. This study evaluated serological screening in pools for hepatitis B virus (HBV) at the Israeli national blood bank and a hospital blood bank in Gaza, the Palestinian Authority. The accuracy of HBV surface antigen (HBsAg) enzyme immunoassay performed on pools of 3-24 samples was compared with individual tests. Delay in detecting positive samples due to dilution in pools and the possibility of antibody-antigen neutralization were analyzed. The sensitivity of pooled testing for HBsAg was 93-99%, prolonging the window period by 5 days (8.3%). Neutralization of HBsAg by hepatitis B surface antibodies (anti-HBs) could be minimized by testing immediately after pooling. Serological testing for HBsAg in pools may be performed using manually created pools of up to six samples, with 5% loss in sensitivity and a risk of neutralization by anti-HBs present in the donor population. Pooling can therefore be considered as an option only in countries with a low prevalence of HBV.

Use of Seroconversion Panels To Estimate Delay in Detection of Anti-Human Immunodeficiency Virus Antibodies by Enzyme-Linked Immunosorbent Assay of Pooled Compared to Singleton Serum Samples

ABSTRACT The transfusion of unsafe blood worldwide accounts for 5 to 15% of new human immunodeficiency virus (HIV) infections, most of which occur in sub-Saharan Africa. While developed countries now apply PCR testing of pooled samples, some developing countries still do not have universal screening policies. More efficient low-cost procedures for the screening of pooled samples have the potential to encourage mass screening efforts in resource-poor settings. The aim of this study was to estimate the delay in the detection of HIV antibodies in pooled serum samples compared to that in singleton serum samples by enzyme-linked immunosorbent assay (ELISA) and to evaluate the risk of transfusion-transmitted HIV infection during the window period. Serial blood samples obtained from five HIV seroconversion panels were mixed with HIV-seronegative blood samples to create pools of 6, 12, 16, 24, 32, and 48 samples. The delay in detection of the first anti-HIV antibody-positive sample in tests with pooled samples was calculated for each pool size and compared to that obtained by testing of singleton samples and statistically evaluated by a robust log-linear regression analysis. The risk of a false-negative (FN) result caused by dilution was estimated by use of the incidence risk/window period model. The additional risk of transmission related to ELISA screening of pooled samples for HIV did not exceed 9% of the current risk of an FN result (estimated to be 1/1,067,000). The countries with virus prevalence rates in donors of less than 15% are expected to save up to 30% in the number of tests. ELISA screening of pooled samples could be considered in settings where the testing of blood supplies for HIV is not routinely done.

Are coping resources related to humoral reaction induced by academic stress? An analysis of specific salivary antibodies to Epstein-Barr virus and cytomegalovirus

The aim of the present study was to investigate whether coping resources mediated the changes in Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) specific salivary antibodies caused by academic stress. Fifty-four first-year female students of nursing and physiotherapy completed pencil and paper written questionnaires and concurrently donated saliva samples. The instrument included the short version of the Sense of Coherence (SOC) scale, measures of social support, current health, health practices, the scale of psychological distress, and state anxiety questionnaire. Data and saliva samples were collected one month after the beginning of the first semester, during term examinations period and a month into the second semester. Statistically significant changes in the level of specific salivary EBV and HCMV antibodies were observed between the four study points. State anxiety and psychological distress were significantly associated with HCMV-specific salivary antibody level increase during examinations and its decrease after the stress was over. Coping resources, however, were not associated with changes in any of the antibodies studied.

Accuracy of hepatitis C virus core antigen testing in pools among seroconverters

BACKGROUND: Screening blood units for hepatitis C virus (HCV) with nucleic acid testing (NAT) reduces the risk associated with the long “window period” (8‐9 weeks) after HCV infection. The feasibility of adding the HCV core antigen assay in pools to the existing anti‐HCV individual screening was examined as an alternative of NAT, for early detection of HCV.

Systemic and splanchnic hemodynamics following hemorrhage and volume restitution with Haemaccel in portal hypertensive rats: The effect of propranolol

Background and Aims: Recently, we found in a portal hypertensive rat model that hemorrhage and volume restitution with Haemaccel, a low viscosity plasma expander, induced an increase in cardiac output and portal venous inflow. The present study was conducted to evaluate whether pretreatment with propranolol will attenuate these hyperdynamic changes.