Human-like scene interpretation by a guided counterstream processing

In modeling vision, there has been a remarkable progress in recognizing a range of scene components, but the problem of analyzing full scenes, an ultimate goal of visual perception, is still largely open. To deal with complete scenes, recent work focused on the training of models for extracting the full graph-like structure of a scene. In contrast with scene graphs, humans' scene perception focuses on selected structures in the scene, starting with a limited interpretation and evolving sequentially in a goal-directed manner [G. L. Malcolm, I. I. A. Groen, C. I. Baker, Trends. Cogn. Sci. 20, 843-856 (2016)]. Guidance is crucial throughout scene interpretation since the extraction of full scene representation is often infeasible. Here, we present a model that performs human-like guided scene interpretation, using an iterative bottom-up, top-down processing, in a "counterstream" structure motivated by cortical circuitry. The process proceeds by the sequential application of top-down instructions that guide the interpretation process. The results show how scene structures of interest to the viewer are extracted by an automatically selected sequence of top-down instructions. The model shows two further benefits. One is an inherent capability to deal well with the problem of combinatorial generalization-generalizing broadly to unseen scene configurations, which is limited in current network models [B. Lake, M. Baroni, 35th International Conference on Machine Learning, ICML 2018 (2018)]. The second is the ability to combine visual with nonvisual information at each cycle of the interpretation process, which is a key aspect for modeling human perception as well as advancing AI vision systems.

Biophysical Characteristics of Erythrocytes during Acute Myocardial Infarction and Venous Thrombosis

The osmotic fragility (OF), density distribution (DDC) and electrophoretic mobility (EPM) of red blood cells were examined in groups of patients suffering from acute myocardial infarction (MI), arteriosclerotic heart disease and precordial pains (ASHD), and deep-vein thrombosis. In patients with acute MI there is a reduction in electric mobility which returns to normal range within 3 weeks. The slow RBCs were in no case slower than the slowest cells of a normal curve representing the oldest portion of the red cell population. In a definite percentage of these patients there are also changes in the OF and the DDC indicating a narrower cell population. These changes are apparently consequent to the disappearance of the slowest cells from the circulation. Mobility tests were done in buffered saline and after three washings. The cell mobility of normal patients was slowed after ½ to 1 hour incubation with the plasma of patients suffering from fresh MI. These results agree with the existence of plasma factors affecting the electric charge of RBCs. The mobility of red blood cells of patients with acute MI underwent incubation with normal plasma returned to normal. The cells of patients with ASHD and precordial pains show also a reduction in average mobility although in a lesser degree. The possibility that this group of patients suffer from micro-infarct not detected by the usual clinical tests, has been considered. Patients with deep-venous thrombosis show similar changes in cell mobility as patients with acute MI. A possible relation between reduced RBC electric mobility and thromboembolism among MI patients was suggested.

Feasibility and cost-benefit of implementing pooled screening for HCVAg in small blood bank settings

To examine the accuracy, feasibility and benefits of screening for hepatitis C virus core antigen (HCVAg) using enzyme-linked immunosorbent assay (ELISA) test in pools. Many countries cannot afford to test blood donations for hepatitis C using molecular methods. Screening individual units using the ELISA HCVAg test is an acceptable, yet still expensive, alternative, especially for small blood bank settings. This study evaluated the option of screening for HCVAg in pools. The sensitivity (Se) and specificity (Sp) of HCVAg in pools of three and six antibody-negative samples were estimated and compared with polymerase chain reaction (PCR). The feasibility and cost-benefit of the assay was assessed on 960 routine samples collected at a hospital blood bank in Gaza. Based on results for 50 PCR-positive pools and 50 and 110 PCR-negative pools of three and six, the Se of testing in pools of three and six samples is 80-82% [95% confidence interval (CI): 66.3-91.4] and Sp >or=98% (95% CI: 89.4-100.0) compared with PCR. The incidence of antigen in donors in Gaza was 0.1% (95% CI: 0-0.56). Cost analyses suggested significant benefits from implementing screening blood donations for HCVAg when the incidence rate is >4.2/10,000, leading to reduction in the expenditures needed to treat patients infected with HCV. The risk of transfusion-transmitted hepatitis C in resource-deprived developing countries can be efficiently reduced by additional screening of antibody-negative blood donations for HCVAg in pools of six.

Estimation of delay in detecting hepatitis C virus antibodies in pools compared to individual testing on seroconversion panels

Testing for anti-hepatitis C virus (HCV) antibodies in pools may reduce blood screening costs, making this approach affordable for developing countries, provided that the dilution of infected blood does not significantly increase the number of undetectable viral particles, especially in seroconverters. This study assessed the delay in detection of HCV antibodies in five HCV seroconversion panels, tested in pools of 6-48 samples, and estimated the risk of transfusion-transmitted HCV caused by pooling. The delay in detection of positive samples was 5-12 days for pools of all sizes, adding 7% to the risk of HCV transmission that occurs when blood donors' samples are tested individually.

Nephrotoxicity of uranyl acetate: effect on rat kidney brush border membrane vesicles

Since the Gulf war exposure to depleted uranium, a known nephrotoxic agent, there is a renewed interest in the toxic effects of uranium in general and its mechanism of nephrotoxicity which is still largely unknown in particular. In order to investigate the mechanism responsible for uranium nephrotoxicity and the therapeutic effect of urine alkalization, we utilized rat renal brush border membrane vesicles (BBMV). Uranyl acetate (UA) caused a decrease in glucose transport in BBMV. The apparent K (i) of uranyl was 139+/-30 microg uranyl/mg protein of BBMV. Uranyl at 140 microg/mg protein of BBMV reduced the maximal capacity of the system to transport glucose [V (max) 2.2+/-0.2 and 0.96+/-0.16 nmol/mg protein for control and uranyl treated BBMV (P<0.001), respectively] with no effect on the apparent K (m) (1.54+/-0.33 and 1.54+/-0.51 mM for control, and uranyl treated BBMV, respectively). This reduction in V(max) is at least partially due to a decrease in the number of sodium-coupled glucose transporters as apparent from the reduction in phlorizin binding to the uranyl treated membranes, V (max) was reduced from 247+/-13 pmol/mg protein in control BBMV to 119+/-3 pmol/mg protein in treated vesicles (P<0.001). The pH of the medium has a profound effect on the toxicity of UA on sodium-coupled glucose transport in BBMV: higher toxicity at neutral pH (around pH 7.0), and practically no toxicity at alkaline pH (7.6). This is the first report showing a direct inhibitory dose and pH dependent effect of uranyl on the glucose transport system in isolated apical membrane from kidney cortex.

Detection of HCV salivary antibodies by a simple and rapid test

Hepatitis C (HCV) is common in developing countries, where blood sampling and expensive sophisticated methods for detection are less available. Hemodialysis patients have high prevalence of HCV and may resemble sick populations in developing countries in relation to immunosuppression and antibodies production. For these reasons anti-HCV antibodies were assayed in saliva of hemodialysis patients by ImmunoComb II assay that is less laborious, relatively inexpensive and easy to perform If the findings are confirmed by larger studies this method may be useful especially in developing countries. Serum and saliva samples were obtained from 37 hemodialysis patients and assayed by ImmunoComb II kit. In positive PCR patients the saliva test had 100% sensitivity, which was as good as serum anti-HCV Axsym testing. Saliva testing had a similar or better specificity than the serum method.

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.

Human cytomegalovirus salivary antibodies as related to stress

Human cytomegalovirus (HCMV) is prevalent in 50-80% of the population worldwide. After primary infection it remains in a latent state until reactivation. Stressful events induce the release of corticosteroids which activate HCMV. The effect of examination stress on HCMV reactivation among first year female students was studied by detecting the values of HCMV specific salivary IgG and IgA antibodies before, during and after two important examinations. Hepatitis A virus (HAV) salivary antibodies served as a non-latent virus control. A statistically significant increase in the level of HCMV specific IgG and IgA antibodies was detected in saliva samples collected during the two examinations, as compared with the samples collected one month before them and two weeks after the grades were posted (p<0.05), whereas HAV antibody levels did not change significantly.

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.

Splanchnic and systemic hemodynamic effects of sustained euglycemic hyperinsulinemia in rats

Insulin, in addition to its metabolic function, was found to induce skeletal muscle vasodilatation after acute administration. The vasoactive effects of sustained euglycemic hyperinsulinemia, especially in the splanchnic circulation, are less well known. The aim of this study was to evaluate the systemic and splanchnic hemodynamic effects of sustained euglycemic hyperinsulinemia. Hyperinsulinemia was induced by a sustained-release insulin implant in the scurf area of male rats (release rate -1 U/day). Beginning on the 3rd day, the study group was fed a glucose-rich diet. Hemodynamic studies were performed on the 5th day using the radioactive microsphere technique. Serum insulin was measured by radioimmunoassay. At the time of the hemodynamic measurements, plasma insulin level was higher in the insulin-treated (n=8) compared to control rats (n=8) (23.6 +/- 4.7 vs. 13.2+/-3.9 microu/mL, respectively; p<0.001). Plasma glucose level of the two groups was similar (5.43 +/- 1.07 vs. 5.83 +/- 1.44 mmol/L, respectively). Abdominal skeletal muscle blood flow was higher in the insulin-treated group (0.11 +/- 0.05 vs. 0.05 +/- 0.04 mL x min(-1) x g(-1), respectively; p<0.02). No significant changes were observed in cardiac output and renal blood flow. In the splanchnic circulation: stomach, pancreatic, intestinal, splenic, hepatic arterial and total hepatic blood flow were also not significantly different. In summary, short-term, sustained euglycemic hyperinsulinemia in rats increased blood flow to skeletal muscle but had no hemodynamic effects on cardiac output or splanchnic circulation.

Salivary HCV-antibodies; a follow-up cohort study of liver disease patients

We have recently shown in Liver Clinic patients that saliva instead of serum may be used for anti-HCV detection. As compared to blood withdrawing, saliva is easier to obtain, non invasive, especially for infants. In the present study, sequential determination of serum and salivary anti-HCV was performed in the same cohort for 36 months. Anti-HCV seropositive and seronegative patients were studied. Blood and saliva samples were obtained simultaneously. From the anti-HCV seronegative patients (n=33), 161 sequential serum and 161 matched saliva samples were obtained. All were anti-HCV negative. From the anti-HCV seropositive patients (n=35), 131 sequential serum and 131 matched saliva samples were obtained. All sequential serum samples were anti-HCV positive. Of the saliva samples 126 (96%) were anti-HCV positive and five (4%) were anti-HCV negative. These five samples were obtained from two patients with autoimmune hepatitis and HCV-RNA seronegative by PCR. The results suggest that saliva may serve as a substitute for serum for the detection of anti-HCV antibodies.

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.

METHODS

Portal hypertension was induced by portal vein constriction. Treatment was initiated 14--21 days later. Propranolol (30 mg/kg per day) or water were administered for 7 days via a gastric gavage. Under ketamine anesthesia, 18 h after the last given dose, blood was withdrawn at a constant rate of 0.3 mL/min for 15 min followed by a 15-min stabilization. Haemaccel was infused at the same rate and volume used for withdrawal. Hemodynamic measurements were performed after volume restitution in both groups by using radioactive microspheres.

RESULTS

Eight rats were studied in each group. In the propranolol-treated animals, portal venous inflow was decreased (2.4 +/- 0.8 vs 3.8 +/- 0.7 mL/min per 100 g bodyweight; P < 0.01), while splanchnic arteriolar and porto-collateral resistance were increased (52.8 +/- 21.0 vs 32.8 +/- 13.0 and 6.0 +/- 1.4 vs 4.1 +/- 0.7 mmHg x min x 100 g bodyweight/mL; P < 0.05, respectively). Cardiac output, mean arterial pressure, heart rate, total peripheral resistance and portal pressure were not significantly different between the two groups.

CONCLUSION

In this model, pretreatment with propranolol prevented the increase in portal venous inflow, which occurs following hemorrhage and volume restitution with Haemaccel. Although caution should be taken in extrapolating data from animal models to humans, our results suggest that volume replacement during a portal hypertensive-related bleeding episode may be safer in a patient treated with non-selective beta-adrenoreceptor antagonists.

Blood viscosity, hemodynamics and vascular hindrance in a rat model of acute controlled bleeding and volume restitution with blood or Haemaccel

BACKGROUND

Hemorrhage and volume restitution with commercially available solutions is followed by reduced blood viscosity. Consequent hemodynamic changes may arise not only from the reduced viscosity itself but also from changes in vascular geometry induced by autoregulation processes. Vascular hindrance reflects the contribution of vascular geometry to flow. Our aim was to explore the possible effects of blood volume restitution with Haemaccel or blood, on regional blood flow and vascular geometry.

METHODS

Under ketamine anesthesia, blood was withdrawn at a 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 as 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

Volume replacement with Haemaccel (n=10), compared to blood (n=10), was followed by increased cardiac output and portal venous inflow (37.1 +/- 9.0 and 3.1 +/- 0.5 vs 25.9 +/- 6.8 and 2.2 +/- 0.9 ml x min(-1) x 100 g bw(-1), respectively; P<0.05), decreased viscosity (2.8 +/- 1.3 vs 3.7 +/- 1.3, respectively; P<0.01) and decreased peripheral and splanchnic arteriolar resistance (3.8 +/- 1.1 and 40.9 +/- 7.6 vs 5.2 +/- 1.7 and 61.1 +/- 29.5 mmHg x ml(-1) x min x 100 g bw, respectively; P<0.05). No significant differences between the groups were observed in vascular hindrance and cardiac output distribution.

CONCLUSION

Volume replacement with Haemaccel, compared to blood, induced increase in systemic and splanchnic blood flows, reflecting mainly changes in viscosity and not in blood vessel geometry. These results suggest no significant difference in overall activation of autoregulation process between volume restitution with blood or Haemaccel.

Epstein-Barr virus specific salivary antibodies as related to stress caused by examinations

Epstein-Barr virus (EBV) is prevalent in 90% of the population. After primary infection it remains in a latent state and the majority of the virus carriers are asymptomatic during their life. Among the immunocompromized patients such as organ and bone marrow transplant recipients, individuals lacking T cell immunity, and patients treated with corticosteroid, cancer, and AIDS patients EBV primary infection and reactivation can cause life threatening diseases. Immunosupression may occur also during stressful events, which induce corticosteroid release and thus activate EBV. The effect of examination stress on EBV reactivation among female students was studied by detecting the values of EBV specific IgG and IgA salivary antibodies. Sequential saliva samples were obtained from first year female students before, during, and after two important examinations. EBV specific IgG and IgA salivary antibodies were tested by enzyme-linked immunosorbent assay (ELISA). Hepatitis A virus (HAV) salivary antibodies served as a non-latent virus control. A statistically significant increase in the values of EBV specific IgG and IgA antibodies was detected in samples collected during the examinations, as compared to the samples collected two months before and one month after the exams (P < 0.05). HAV antibody levels did not change significantly between the four time points. The menstrual cycle had no significant effect on the results. No significant symptoms were reported during the whole study. These results indicate that among female students who endure stress during academic examinations, a significant increase in EBV specific IgG and IgA salivary antibody values could be detected. EBV reactivation should be confirmed by measuring salivary EBV DNA or infectious virus.

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.

Chronic pain in Holocaust survivors

There is limited research on the connection between the Holocaust and chronic pain, despite evidence suggesting that medical and psychological sequelae are common in survivors. The goals of this study were: (1) to define Holocaust survivors' (n = 33) chronic pain characteristics as manifested 50 years after the war, (2) to compare survivors with controls (n = 33) who did not experience World War II atrocities, and (3) to investigate the connection between past trauma and chronic pain. Data were collected through questionnaires that included a detailed medical and pain history, visual analog scale (VAS), McGill Pain Questionnaire (MPQ), Beck Depression Inventory (BDI), Symptom Check List-90 (SCL-90), and Pain Disability Index (PDI). A comparison of variables between the two groups was conducted using multivariate analysis of variance (MANOVA) and ANOVA, and canonical discriminant analysis. Results showed that Holocaust survivors reported higher pain levels (73 +/- 18 vs. 56 +/- 21; P < 0.005), more pain sites (4.5 6 2.8 vs. 2.7 6 1.4; P < 0.05), and significantly higher depression scores (17.6 +/- 8.4 vs. 9.2 +/- 4.6; P < 0.001); they tended to utilize more medical services (5.9 +/- 3.0 vs. 5.1 +/- 2.8). Nonetheless, survivors did not regard themselves more disabled as compared with controls. They reported a higher activity level as measured by walking distance capacity, and spent significantly fewer hours resting (4.3 +/- 3.6 vs. 7 +/- 4.6; P < 0.05). This paradoxical combination of high pain intensity, moderate to severe depression, and high activity level characterizes Holocaust survivors' chronic pain. It is conceivable that by remaining active Holocaust survivors fight back their pain, distress, and depression. These findings suggest that Holocaust atrocities affect survivors' chronic pain even years later.

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 1 b 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).

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 1 b 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).

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-seropositive 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.

Prevalence of specific IgA and IgM anti-HBc antibodies compared with HBV DNA in the sera of HBsAg chronic carriers

OBJECTIVE

We evaluated the significance of IgA antibodies directed against the hepatitis B virus core antigen (IgA anti-HBc) as a marker for viral replication.

STUDY DESIGN/METHODS

Serum samples of 143 hepatitis B surface antigen (HBsAg) carriers and 189 HBsAg-negative subjects were studied. Hepatitis B virus (HBV) DNA was detected by polymerase chain reaction. IgA anti-HBc was determined by a capture enzyme-linked immunosorbent assay developed in our laboratory. The results were compared with those for IgM anti-HBc, which were determined by a commercially available method.

RESULTS

IgA anti-HBc was detected in 57 (40%) and HBV DNA in 38 (27%) of the HBsAg carriers. Among the HBsAg-negative subjects, IgA anti-HBc and HBV DNA were detected simultaneously in four samples. All 42 HBV DNA-positive samples were IgA anti-HBc positive. IgM anti-HBc was detected in 27 (64%) of them.

CONCLUSIONS

IgA anti-HBc is a sensitive marker for HBV replication, and its absence may exclude HBV replication. The role of IgA anti-HBc in monitoring response to therapy and predicting clinical course is being evaluated.

Hemodynamic characterization of the diabetic Psammomys obesus--an animal model of type II diabetes mellitus

The hemodynamic changes occurring early in the course of non-insulin-dependent diabetes mellitus (Type II, NIDDM) are not well understood. We applied the radioactive microspheres technique at an early stage of diabetes in Psammomys abesus (sand rat), an established animal model of spontaneous NIDDM. Ten diabetic and 7 control male animals were studied. Plasma glucose and insulin levels in the diabetic group were significantly higher than in the control group (21.3 +/- 2.1 vs. 6.2 +/- 1.1 mmol/l, and 2,650 +/- 480 vs. 770 +/- 120 pmol/l, respectively). Mean arterial blood pressure, heart rate, cardiac output, splanchnic blood flow, muscular blood flow, and total peripheral resistance were not statistically different between the two groups. Renal blood flow was significantly lower in the diabetic group (7.45 +/- 0.32 vs. 10.48 +/- 0.99 ml/min) and renal arterial resistance was higher (11.65 +/- 0.93 vs. 8.33 +/- 0.76 mm Hg.min/ml) compared with the control group. These results suggest that increased renal resistance and decreased renal blood flow may be the initial hemodynamic alterations in NIDDM. The combination of this animal model with the radioactive microspheres technique provides a new tool for studying the physiopathology, the natural history of hemodynamic changes, and possible therapeutic interventions of Type II diabetes.

HBsAg confirmation: an experimental test

BACKGROUND

The specificity of HBsAg testing is to be confirmed with antibody blocking to avoid false positive results.

OBJECTIVE

To test the experimental HrAb HBsAg-blocking activity and to use this new antibody in the verification of repeatedly reactive HBsAg blood serum samples.

STUDY DESIGN

HbsAg screening of three quality control panels was followed by a comparative confirmatory test with commercial HuAb and experimental HrAb. The HrAb was used in subsequent HBsAg confirmation trials.

RESULTS

A good agreement in the results obtained using the two antibodies was found, independently of the type of HBsAg neutralization step performed (either preincubation or competitive inhibition). Of the 97 repeatedly reactive HBsAg blood serum samples, 79 were 'confirmed positives'. On repeated confirmations by two antibodies, 13/18 'not confirmed' converted to 'confirmed positives', while the same five samples still remained false positive.

CONCLUSION

The results suggest that (1) HrAb is as good as HuAb in HBsAg confirmation and (2) HBsAg confirmatory testing is essential in the laboratory examinations of the HBsAg repeatedly reactive samples.

Chronic, burning facial pain following cosmetic facial surgery

Chronic, burning facial pain as a result of cosmetic facial surgery has rarely been reported. During the year of 1994, two female patients presented themselves at our Pain Relief Clinic with chronic facial pain that developed following aesthetic facial surgery. One patient underwent bilateral transpalpebral surgery for removal of intraorbital fat for the correction of the exophthalmus, and the other had classical face and anterior hairline forehead lifts. Pain in both patients was similar in that it was bilateral, symmetric, burning in quality, and aggravated by external stimuli, mainly light touch. It was resistant to multiple analgesic medications, and was associated with significant depression and disability. Diagnostic local (lidocaine) and systemic (lidocaine and phentolamine) nerve blocks failed to provide relief. Psychological evaluation revealed that the two patients had clear psychosocial factors that seemed to have further compounded their pain complaints. Tricyclic antidepressants (and biofeedback training in one patient) were modestly effective and produced only partial pain relief.

Hemodynamic effects of hypothyroidism induced by methimazole in normal and portal hypertensive rats

Portal hypertension is accompanied by a hyperdynamic circulatory state that shares some similarities with thyrotoxicosis. This study was conducted in order to investigate the hemodynamic effects of hypothyroidism in a rat model with portal hypertension induced by partial portal vein ligation (PVL). Four groups of 10 rats each were studied: normal control and hypothyroid rats, and PVL control and hypothyroid rats. Hypothyroidism was induced by methimazole 0.04% in drinking water. Hemodynamic measurements were performed using the radioactive microsphere technique. Induction of hypothyroidism was confirmed by elevated TSH levels. In the PVL groups, hypothyroidism ameliorated the hyperdynamic circulation. Portal venous inflow and portal pressure dropped significantly: 7.1 +/- 0.2 vs 4.8 +/- 0.3 ml/min/100 g body wt (P < 0.01) and 13.4 +/- 0.9 vs 10.9 +/- 0.8 mm Hg; (P < 0.01), respectively. In normal rats, hypothyroidism was manifested by a hypodynamic circulatory state. These results demonstrate that hypothyroidism induced by methimazole is followed by amelioration of the hyperdynamic circulation, normalization of portal venous inflow, and reduction of portal pressure.

Distinct intracellular lysozyme content in normal granulocytes and monocytes: a quantitative immunoperoxidase and ultrastructural immunogold study

Using two different immunological methods, we performed a quantitative estimation of lysozyme (LZ) in normal mature granulocytes and monocytes. An immunoperoxidase reaction for LZ in granulocytes and monocytes of 10 healthy donors measured by a scanning microdensitometer as arbitrary units showed a significantly higher LZ content in granulocytes than in monocytes. An ultrastructural immunogold reaction (IGR) for LZ performed on post-embedded thin sections showed a higher number of total gold grains in neutrophilic granulocytes than in monocytes. In monocytic granules we found a high density of gold grains per micron 2, whereas in granulocytic granules lower values were obtained. In granulocytes, LZ was found in both primary myeloperoxidase (MPO)-positive and secondary MPO-negative granules, and in monocytes the granules showed weak MPO reactivity and high LZ content. Granulocytes previously subjected to phagocytosis of bacteria and latex particles showed release of LZ on degranulation inside the phagosome, whereas in monocytes the granules remained outside the phagosome and released LZ without degranulation. Our study demonstrated a significantly higher total LZ content in granulocytes, a higher granular LZ content in monocytes, and release of LZ from intact monocyte granules during phagocytosis.

Increased neutrophil function induced by bile duct ligation in a rat model

Neutrophil function was studied in rats with common bile duct ligation. Superoxide production stimulated by phorbol myristate acetate, opsonized zymosan or formyl-methionyl-leucyl-phenylalanine; phagocytosis; and chemotaxis were significantly greater in neutrophils from rats with common bile duct ligation than in sham-operated control rats. Enhanced neutrophil activity was observed within 12 hr of bile duct ligation; it remained increased during the 15-day study. Preincubation of neutrophils from control rats with sera of rats with common bile duct ligation did not increase superoxide generation. This suggests that the high superoxide production observed in neutrophils of rats with common bile duct ligation was not an immediate effect of the serum. Neutrophils of rats with portal vein ligation exhibited normal activity, indicating that portal systemic shunting per se is not the underlying mechanism for increased activity. The elevated levels of AST and alkaline phosphatase, indicating liver damage, that appeared within 12 hr of bile duct ligation correlated with the increased superoxide generation.

Bromosulfophthalein disposition in chronically bile duct obstructed rats

The disposition of bromosulfophthalein was studied in chronically bile duct obstructed rats. In this model a catheter was inserted into the common bile duct and the distal tip was sealed. Resumption of bile flow was achieved with great ease. Obstruction of bile duct for 18 days in rats resulted in elevated bilirubin, ALT, AST, and alkaline phosphatase levels. Portal hypertension developed within this period (11.6 +/- 0.5 in obstructed rats vs. 8.6 +/- 0.6 mm Hg in sham-operated group). After the bile duct obstruction was opened, the half-life time for elimination of bromosulfophthalein (42.30 +/- 6.47 min) was longer than in sham-operated rats (21.23 +/- 3.34 min). Plasma clearance was reduced by 70% in bile duct obstructed rats. In spite of increased bile flow rate, biliary excretion of the dye was reduced by 40% in chronically bile duct obstructed rats. Hepatic glutathione levels were significantly reduced by 20% in this model. The specific activity of glutathione S-transferase with chlorodinitrobenzene and styrene oxide, as substrates, was reduced by 50% and 30%, respectively. However, the percent of conjugated bromosulfophthalein in bile was similar to that of sham-operated rats.

The effectiveness of a layered baseplate training aid in the preclinical instruction of second-year dental students

The effectiveness of the Cavidrill baseplate in the training of second-year dental students in cavity preparations in primary ivorine teeth was assessed. The preclinical class of 112 students was divided into four groups: Cavidrill-only group, two groups combining Cavidrill training with traditional typodont training, and a typodont-only group. The Cavidrill baseplate was found not to improve the students' performance in cavity preparation when assessed on midterm and final examinations.

Hemodynamic characterization of conscious and ketamine-anesthetized bile duct-ligated rats

The present study was conducted to characterize the hemodynamic alterations in common bile duct-ligated (CBDL) rats under ketamine anesthesia and in the awake restrained state. Hemodynamic studies using the radioactive microspheres technique were performed 17.6 +/- 0.6 (SE) days after bile duct ligation or sham operation. CBDL rats had lower mean arterial pressure, reduced systemic and renal resistance, and increased renal blood flow compared with sham-operated rats. This was found both in the conscious and anesthetized states. Anesthetized CBDL rats had higher portal pressure (13.2 +/- 0.5 vs. 9.2 +/- 0.4 mmHg; P less than 0.001) and lower splanchnic arteriolar resistance (15.4 +/- 1.3 vs 26.8 +/- 4.6 mmHg.ml-1.min.100 g body wt; P less than 0.05) than sham-operated rats. Portosystemic shunting was 52.3 +/- 11.7% in CBDL and negligible in sham-operated rats. The last three parameters could not be measured in conscious animals. Total peripheral resistance was lower in the conscious than in the anesthetized state, diverting a higher fraction of cardiac output at the expense of splanchnic organs and leading to a significant reduction of portal venous inflow in sham-operated but not in CBDL rats [3.36 +/- 0.47 vs. 5.38 +/- 0.65 (P less than 0.05) and 5.33 +/- 0.58 vs. 6.34 +/- 0.37 ml.min-1.100 g body wt-1 (P = NS), respectively]. These findings indicate that CBDL and normal rats respond differently to anesthesia and restraint. Because the restrained state is stressful and studies in anesthetized animals are technically simpler, provide additional information such as portal pressure and portosystemic shunting, and diminish animal suffering, we suggest that hemodynamic studies in rats, using the microsphere technique, should be preferably performed under ketamine anesthesia.

Intrinsic potential for high fetal hemoglobin production in a Druz family with beta-thalassemia is due to an unlinked genetic determinant

The mechanism for elevated production of fetal hemoglobin (Hb F) in a Druze patient with beta zero-thalassemia intermedia was investigated. Heterozygous family members exhibited normal Hb F levels, suggesting that the increase in gamma-gene expression in the propositus may be partly due to anemic stress. Erythroid progenitors of these family members cultured in vitro [burst forming units (erythroid); (BFUe)] showed elevated synthesis of Hb F, indicating the existence of a genetically determined intrinsic capacity for high Hb F production in this family. The propositus was found to be homozygous for a IVS2-position 1 mutation, on the background of Mediterranean haplotype I, which is not known to be linked to high Hb F production. Moreover, extensive molecular studies of the beta-globin gene cluster, including sequence analysis of the promoter regions of the gamma-globin genes, did not reveal any cis- actin mechanism that could account for the high Hb F production in the propositus. A young niece of the propositus with beta zero-thalassemia major was recently discovered, who was homozygous for the same beta-globin allele and haplotype as the propositus. However, unlike her uncle, she does not have a high Hb F level and presents with a severe clinical course. Her inability to produce high Hb F suggests that the genetic determinant for increased gamma-gene expression in the propositus is unlinked to the beta-globin gene cluster.

Changes in theophylline metabolism during postnatal development in rat liver slices

The metabolism of theophylline was studied in liver slices of young and adult rats. Theophylline and six metabolite fractions were recognized in adult liver by thin-layer radiochromatography and high performance liquid chromatography: 1-methyluric acid; 1-methylxanthine; 1,3-dimethyluric acid and/or 3-methylxanthine; caffeine; a uracil derivative and two unknown polar compounds. Preincubation with caffeine or theobromine inhibited theophylline metabolism. Allopurinol decreased the formation of three metabolite fractions but markedly increased the production of 1-methylxanthine. SKF 525-A inhibited the overall metabolism of theophylline. The specific activity of the enzyme system was 3.2 +/- 0.4 nmoles X (g liver)-1 X hr-1 in the 4- to 5-day-old rat and increased to a peak of 25.7 +/- 1.7 in the 28-day-old; values for Km and Vmax in the 7- and 28-day-olds were 132.1 and 67.5 microM, and 23.9 and 52.1 nmoles X (g liver)-1 X hr-1 respectively. Theophylline and the same six metabolites were identified in young and adult rats, but the development pattern was not uniform. Peak age-related activity and involvement of mixed-function oxidase system are features which are common to theophylline and caffeine metabolism. Xanthine oxidase played a role in theophylline metabolism. Formation of caffeine from theophylline was not dependent on a lack of activity of other pathways.

EMC virus infection in baboons as a model for studies on antiviral substances

EMC virus causes a lethal infection in baboon monkeys within 4-8 days following subcutaneous injection with 10(4)-10(8) pfu of virus. The infection is accompanied by viremia, invasion of heart muscle and of brain. Monkeys infected with 10(6) pfu of EMC virus were treated with human leukocyte interferon. The interferon was injected intramuscularly first 0, 0.5, 6 and 24 h post-infection, then twice daily with a dose of 3 X 10(6) units for 5 consecutive days. All the monkeys treated with interferon remained alive and healthy. Animals infected with EMC virus, but not treated with interferon died within 6 days with evidence of myocarditis. The EMC virus-interferon interaction in baboon monkeys seems to provide a useful primate model system for testing the prophylactic and therapeutic antiviral activity of interferons or other antiviral substances.

1,3,8-Trimethylallantoin: a major caffeine metabolite formed by rat liver

The formation of 1,3,8-trimethylallantoin from caffeine is demonstrated for the first time in vitro in rat liver slices. This compound constitutes 15% of total in vitro metabolites. With this identification, all the metabolic pathways of caffeine shown in vivo (N-demethylation, oxidation to uric acids and formation of uracil and allantoin derivatives) are demonstrated in vitro.

Urinary metabolites of caffeine in the premature infant

Caffeine metabolites in urine from premature infants were analysed by TLC and HPLC. Caffeine, dimethyluric acids, mono- and dimethylxanthines and, for the first time, a uracil derivative (6-amino-5-[N-methylformylamino]-1,3-dimethyluracil) were identified.

Myeloproliferative disorders terminating in acute micromegakaryoblastic leukaemia

Two cases of myeloproliferative disorder--one of myelofibrosis with agnogenic myeloid metaplasia and one of chronic granulocytic leukaemia terminating in acute micromegakaryoblastic leukaemia--are presented. The clinical course is described, and results are reported of morphological, cytometric, cytochemical and cytogenetic studies, as well as cell culture of blood cells in soft agar and in fluid medium.