Demonstrating the reliability of in vivo metabolomics based chemical grouping: towards best practice

While grouping/read-across is widely used to fill data gaps, chemical registration dossiers are often rejected due to weak category justifications based on structural similarity only. Metabolomics provides a route to robust chemical categories via evidence of shared molecular effects across source and target substances. To gain international acceptance, this approach must demonstrate high reliability, and best-practice guidance is required. The MetAbolomics ring Trial for CHemical groupING (MATCHING), comprising six industrial, government and academic ring-trial partners, evaluated inter-laboratory reproducibility and worked towards best-practice. An independent team selected eight substances (WY-14643, 4-chloro-3-nitroaniline, 17α-methyl-testosterone, trenbolone, aniline, dichlorprop-p, 2-chloroaniline, fenofibrate); ring-trial partners were blinded to their identities and modes-of-action. Plasma samples were derived from 28-day rat tests (two doses per substance), aliquoted, and distributed to partners. Each partner applied their preferred liquid chromatography-mass spectrometry (LC-MS) metabolomics workflows to acquire, process, quality assess, statistically analyze and report their grouping results to the European Chemicals Agency, to ensure the blinding conditions of the ring trial. Five of six partners, whose metabolomics datasets passed quality control, correctly identified the grouping of eight test substances into three categories, for both male and female rats. Strikingly, this was achieved even though a range of metabolomics approaches were used. Through assessing intrastudy quality-control samples, the sixth partner observed high technical variation and was unable to group the substances. By comparing workflows, we conclude that some heterogeneity in metabolomics methods is not detrimental to consistent grouping, and that assessing data quality prior to grouping is essential. We recommend development of international guidance for quality-control acceptance criteria. This study demonstrates the reliability of metabolomics for chemical grouping and works towards best-practice.

Maladaptive self-focused attention and default mode network connectivity: a transdiagnostic investigation across social anxiety and body dysmorphic disorders

Maladaptive self-focused attention (SFA) is a bias toward internal thoughts, feelings and physical states. Despite its role as a core maintaining factor of symptoms in cognitive theories of social anxiety and body dysmorphic disorders (BDDs), studies have not examined its neural basis. In this study, we hypothesized that maladaptive SFA would be associated with hyperconnectivity in the default mode network (DMN) in self-focused patients with these disorders. Thirty patients with primary social anxiety disorder or primary BDD and 28 healthy individuals were eligible and scanned. Eligibility was determined by scoring greater than 1SD or below 1SD of the Public Self-Consciousness Scale normative mean, respectively, for each group. Seed-to-voxel functional connectivity was computed using a DMN posterior cingulate cortex (PCC) seed. There was no evidence of increased DMN functional connectivity in patients compared to controls. Patients (regardless of diagnosis) showed reduced functional connectivity of the PCC with several brain regions, including the bilateral superior parietal lobule (SPL), compared to controls, which was inversely correlated with maladaptive SFA but not associated with social anxiety, body dysmorphic, depression severity or rumination. Abnormal PCC-SPL connectivity may represent a transdiagnostic neural marker of SFA that reflects difficulty shifting between internal versus external attention.

A Coclinical Radiogenomic Validation Study: Conserved Magnetic Resonance Radiomic Appearance of Periostin-Expressing Glioblastoma in Patients and Xenograft Models

PURPOSE

Radiomics is the extraction of multidimensional imaging features, which when correlated with genomics, is termed radiogenomics. However, radiogenomic biological validation is not sufficiently described in the literature. We seek to establish causality between differential gene expression status and MRI-extracted radiomic-features in glioblastoma.

EXPERIMENTAL DESIGN

Radiogenomic predictions and validation were done using the Cancer Genome Atlas and Repository of Molecular Brain Neoplasia Data glioblastoma patients (n = 93) and orthotopic xenografts (OX; n = 40). Tumor phenotypes were segmented, and radiomic-features extracted using the developed radiome-sequencing pipeline. Patients and animals were dichotomized on the basis of Periostin (POSTN) expression levels. RNA and protein levels confirmed RNAi-mediated POSTN knockdown in OX. Total RNA of tumor cells isolated from mouse brains (knockdown and control) was used for microarray-based expression profiling. Radiomic-features were utilized to predict POSTN expression status in patient, mouse, and interspecies.

RESULTS

Our robust pipeline consists of segmentation, radiomic-feature extraction, feature normalization/selection, and predictive modeling. The combination of skull stripping, brain-tissue focused normalization, and patient-specific normalization are unique to this study, providing comparable cross-platform, cross-institution radiomic features. POSTN expression status was not associated with qualitative or volumetric MRI parameters. Radiomic features significantly predicted POSTN expression status in patients (AUC: 76.56%; sensitivity/specificity: 73.91/78.26%) and OX (AUC: 92.26%; sensitivity/specificity: 92.86%/91.67%). Furthermore, radiomic features in OX were significantly associated with patients with similar POSTN expression levels (AUC: 93.36%; sensitivity/specificity: 82.61%/95.74%; P = 02.021E-15).

CONCLUSIONS

We determined causality between radiomic texture features and POSTN expression levels in a preclinical model with clinical validation. Our biologically validated radiomic pipeline also showed the potential application for human-mouse matched coclinical trials.

A Comprehensive Review of Genomics and Noncoding RNA in Gliomas

Glioblastoma (GBM) is the most malignant primary adult brain tumor. In spite of our greater understanding of the biology of GBMs, clinical outcome of GBM patients remains poor, as their median survival with best available treatment is 12 to 18 months. Recent efforts of The Cancer Genome Atlas (TCGA) have subgrouped patients into 4 molecular/transcriptional subgroups: proneural, neural, classical, and mesenchymal. Continuing efforts are underway to provide a comprehensive map of the heterogeneous makeup of GBM to include noncoding transcripts, genetic mutations, and their associations to clinical outcome. In this review, we introduce key molecular events (genetic and epigenetic) that have been deemed most relevant as per studies such as TCGA, with a specific focus on noncoding RNAs such as microRNAs (miRNA) and long noncoding RNAs (lncRNA). One of our main objectives is to illustrate how miRNAs and lncRNAs play a pivotal role in brain tumor biology to define tumor heterogeneity at molecular and cellular levels. Ultimately, we elaborate how radiogenomics-based predictive models can describe miRNA/lncRNA-driven networks to better define heterogeneity of GBM with clinical relevance.

Recognizing new opportunities: reconceptualizing policy advocacy in everyday organizational practice

Policy advocacy is a concept that is of both practical and historical importance to the profession of social work. To keep up with developments in how advocacy is practiced at the ground level, however, social work research on advocacy needs to expand in scope. Changes in government contracting and public management practices have reshaped the opportunity structure for policy advocacy, incentivizing a kind of advocacy that is routine, professionalized, and collaborative. At the same time, these practices have raised questions about democratic representation and the degree to which social work advocacy adequately reflects client concerns. This article presents a model for how policy advocacy can be usefully reconceptualized to account for changes in the policy and funding environment and concludes by suggesting ways that social work research and theory can better reflect practice realities.

Evaluating the relation between psychopathy and affective empathy: two preliminary studies

It is widely believed that impairment in an ability to experience affective empathy for others is a central feature of psychopathy. The authors tested this assumption by covertly manipulating and measuring state experiences of emotional contagion and empathic concern in college undergraduates and male forensic inpatients. Surprisingly, they found little evidence of a negative association between psychopathy and affective empathy in either sample. In those instances in which associations were found, they tended to indicate that higher psychopathy was associated with increased affective empathy. Follow-up analyses also revealed that psychopathy was positively associated with pervasive experiences of sadness, anger, and fear, and negatively associated with pervasive experiences of happiness among nonforensic individuals. This research raises questions about existing conceptualizations of interpersonal affect in psychopathy and offers suggestions for advancing future understanding of the role-played by emotional processes in psychopathy.

436 RISK ANALYSIS OF α-LACTALBUMIN TRANSGENE TRANSFER TO NONTRANSGENIC CONTROL ANIMALS DURING REARING, BREEDING, PARTURITION AND LACTATION

Assessment of general risk posed from transgenic (T) animals is important to their future contributions to society. Identification of potentially harmful properties of transgenic livestock is the initial step in a risk assessment. We previously developed and characterized transgenic swine containing a mammary-specific transgene (bovine a-lactalbumin, bALAC) that results in increased milk production in sows. We are currently determining whether bALAC is expressed in tissues of T swine other than the lactating mammary gland and whether the transgene DNA (Tg) crosses into nontransgenic control (C) swine under various physiological and physical conditions. The specific aims addressed in the present study were to determine (1) whether the Tg can be transferred directly by physical association or contact; (2) whether the Tg can be transferred directly via mating; (3) whether the Tg can be transferred directly during gestation and parturition; and (4) whether the Tg can be transferred directly during lactation. The T animals utilized in these studies are in at least generation 10 and have stable incorporation of the Tg. Comparable age- and weight-matched animals, T and C, were housed together allowing general contact that is normal in swine production, for either 180, 220, or 250 days of age after weaning. Swine typically ingest saliva, regurgitated food, and stool or urinary products, as well as other bodily fluids and cells during normal housing. In the second study, vaginal, cervical, uterine, oviductal, and ovarian tissues from C females on 2, 7, or 90 days after mating to T males, and penis, bulbourethral gland, urethra, testis, and epididymis tissues from C males on 2 or 7 days after mating to Tg females were collected. The presence of Tg in tissues from all C animals was tested by using PCR. We have analyzed for the presence of the Tg in various tissues [including mammary gland, salivary gland, skin (sebaceous gland), muscle, lung, liver, kidney, brain, ovary, oviduct, uterus, cervix, vagina, penis, bulbourethral gland, urethra, testis, epididymis, blood, inner and outer placental membranes and intestine]. Results indicate no presence of the Tg in tissues of C animals (n = 28) after co-habitation for 180, 220, or 250 days (n = 305 samples analyzed) or at 2 (n = 7), 7 (n = 16), or 90 (n = 6) days post-mating (n = 72, 192, or 71 samples analyzed, respectively). At Day 112 of gestation, all the samples (n = 78 samples analyzed) from nontransgenic piglets (n = 13) whose dam was aTg female were negative except for the outer placental membrane (n = 13), which screened positive for the transgene. This is not surprising because the outer placental membrane is in close contact with the uterus of the Tg dam. Finally, control piglets (n = 4) that were cross-fostered (3 days after birth) and suckled Tg dams showed no evidence of the transgene in their tissues (n = 20 samples analyzed) at weaning. The present results suggest that there is no horizontal Tg transmission between T and C pigs caused by rearing, mating, gestation, or lactation. This project was supported by USDA BRAG Project #2005-03799.

311 RISK ANALYSIS OF ALPHA-LACTALBUMIN TRANSGENE TRANSFER TO NON-TRANSGENIC CONTROL ANIMALS DURING REARING AND BREEDING

Assessment of general risk posed from transgenic (T) animals is important to their future contributions to society. Identification of potentially harmful properties of transgenic livestock is the initial step in a risk assessment. Direct and indirect impacts of potential harmful properties of T livestock need to be evaluated at 3 levels, namely (1) characterization of how the transgene, its product, and the T livestock behave in their immediate environment, that is, in their barn or pen; (2) determination of possible impacts of large-scale release of T livestock, that is, if they were to be integrated into the larger population of food animal livestock; and (3) determination of the more complex environmental and safety consequences of their release into livestock populations. We previously developed and characterized transgenic swine containing a mammary-specific transgene (bovine α-lactalbumin, bALAC) that results in increased milk production in sows. We currently are determining whether bALAC is expressed in tissues of T swine other than the lactating mammary gland and whether the transgene DNA (Tg) crosses into non-transgenic control (C) swine under various physiological and physical conditions. The specific aims addressed in the present study were to determine: (1) whether the Tg can be transferred directly from T animals to C animals by physical association or contact and (2) whether the Tg can be transferred directly from an adult T animal to an adult C animal via mating. The T animals utilized in these studies are in at least generation 10 and have stable incorporation of the Tg. Comparable age- and weight-matched animals, T and C, were housed together allowing for general contact that is normal within swine production, for either 180, 220, or 250 d of age after weaning. Swine due to their behavior ingest saliva, regurgitated food, and stool or urinary products, as well as other bodily fluids and cells during normal housing. In a second study, vaginal, cervical, uterine, oviductal, and ovarian tissues from C females on 2, 7, or 90 d after mating to T males and penis, bulbourethral gland, urethra, testis, and epididymis tissues from C males on 2 or 7 days after mating to Tg females were collected. The presence of Tg in tissues from all C animals was tested via PCR. We have analyzed for the presence of the Tg in various tissues [including mammary gland, salivary gland, skin (sebaceous gland), muscle, lung, liver, kidney, brain, ovary, oviduct, uterus, cervix, vagina, penis, bulbourethral gland, urethra, testis, epididymis, and intestine]. Results indicate no presence of the Tg in tissues of C animals (n = 28) after co-habitation for 180, 220, or 250 d (n = 305 samples analyzed) or at 2 (n = 5), 7(n = 14), or 90 (n = 2) d post-mating (n = 60, 174, or 24 samples analyzed, respectively). The present results suggest that there is no horizontal Tg transmission between T and C pigs due to rearing or mating. This work provides a critical step toward providing rigorous scientific data for risk assessment of transgenic livestock. This project supported by the USDA BRAG Project #2005-03799.

Impact of preadjusting a quantitative phenotype prior to sib-pair linkage analysis when gene x environment interaction exists

The investigation of potential gene x environment (G x E) interactions is an important facet in the study of complex diseases. When G x E interaction exists, linkage analyses of the interacting gene must treat the environmental factor appropriately. Specifically, the common approach of regressing out an environmental factor prior to linkage analysis may be inappropriate if that factor has an interaction with the gene. This is explored here in the Genetic Analysis Workshop 12 simulated data set using the G x E interaction between major gene four (MG4) and environmental factor two (E2). The analysis shows that preadjusting the quantitative trait three (Q3) phenotype for the main effects of several environmental variables, including one (E2) that interacts with MG4, affects the results of a Haseman-Elston linkage analysis. In particular, the agreement in detecting linkage between preadjusting versus not preadjusting was only 78% and 66% using alpha levels of 0.05 and 0.10, respectively. For both approaches, incorporating an interaction term in the regression models enabled linkage to be detected where the evidence was either minimal or not present in an identical-by-descent main effects-only model. Furthermore, preadjustment for E2 did not appear to account for the major discrepancies between the approaches.

Lack of association between a polymorphism in the interleukin-13 gene and total serum immunoglobulin E level among nuclear families in Costa Rica

BACKGROUND

IL-13 has been implicated in the pathogenesis of asthma and in the regulation of IgE synthesis in humans. Single nucleotide polymorphisms (SNPs) in the IL-13 gene have been associated with asthma and total serum IgE level in Caucasian populations.

OBJECTIVE

To test for genetic association between an SNP in exon 4 of the IL-13 gene (IL-13 + 2044 or Arg130Gln) and total serum IgE level and asthma-related phenotypes in a population with high prevalence of asthma living in Costa Rica.

METHODS

Family-based association study.

RESULTS

Among 83 Costa Rican school children with asthma and their parents (249 individuals), there was no evidence of linkage disequilibrium between the IL-13 + 2044 SNP and any of the outcomes of interest (total serum IgE level on a logarithmic scale, number of positive skin tests to aeroallergens, and asthma). These results were not significantly changed after adjustment for age and gender.

CONCLUSIONS

No significant evidence of linkage disequilibrium between an SNP in exon 4 of the IL-13 gene and total serum IgE level, sensitization to allergens or asthma was found in a family-based association study in Costa Rica.

Cardiovascular risk factors in normotensive and hypertensive Egyptians

OBJECTIVES

To define the prevalence of cardiovascular risk factors and their relation to the level of blood pressure, in Egyptians.

METHODS

Data were collected during the Egyptian National Hypertension project, a national hypertension survey in Egypt. During phase I of the survey, hypertensive (HT) patients were identified. In phase II, clinical and laboratory evaluations were made on HT and gender-matched normotensives (NT). A total of 2313 individuals were examined, 311 NT males, 443 NT females, 670 HT males and 889 HT females.

RESULTS

The prevalence of obesity was 33 and 47% in hypertensive men and women, respectively. After adjusting for age, HT men had significantly higher heart rate, total cholesterol (TC), triglycerides (TG), fasting blood sugar (FBS), post-prandial blood sugar (PBS), body mass index and waist/hip (W/H) ratio than their NT counterparts. In addition, HT women had higher low-density lipoprotein cholesterol (LDL-C). The prevalence of elevated LDL-C and FBS increased with age. The prevalence of hypertriglyceridemia, elevated FBS and obesity rose with increasing level of blood pressure (BP). From the 25-34 to the 55-64 age group, the percentage of hypertensives with > or = 2 risk factors rose from 42.9 to 60.6% in men, and from 9.4 to 46.2% in women. All risk factors were more prevalent in urban populations.

CONCLUSION

This is one of the few reports on the prevalence of cardiovascular risk factors in a developing country. Risk factors cluster with rising level of BP and with ageing. Obesity is very prevalent, particularly in hypertensive Egyptian women. Health efforts directed at the prevention and treatment of obesity should be a high priority.

Improving laboratory results turnaround time

BACKGROUND

Physicians need prompt results of laboratory tests before early morning rounds or on a stat basis to support time-critical decisions that can impact patient care or length of stay. At The Methodist Hospital, we formed a multidisciplinary performance improvement team that was successful in reducing the length of time between collection of specimen and availability of laboratory test results (turnaround time). Our goals were to have Stat results available in less than 60 minutes, and results for morning blood tests available by 8 AM for acute care units and 7 AM for critical care units.

METHODS

Before making changes, we first devised a system of measurement. The most efficient way to obtain data was to query the mainframe laboratory information system for times of specimen collection, times for reception in the laboratory, and times for results verification. We also decided that patient-specific information on specimens that did not meet the goals-exceptions-would be crucial for effective follow-up and corrective action. During several measurement and assessment cycles, we identified opportunities to improve our process.

RESULTS

The percentage of early morning specimens meeting the specified turnaround time improved from 60% in August 1995, to greater than 90% in May 1996. The average turnaround time for early morning specimens takes only 95 minutes rather than 186 minutes. The average turnaround time for a stat specimen declined from 69 minutes to 45 minutes during this process. The volume of stat specimens has also declined significantly.

CONCLUSION

Laboratory test results turnaround time is impacted by a variety of health-care providers, and a multidisciplinary team can work together to improve prompt availability of test results to support time-critical decisions.

The economic impact of corporate wellness programs: past and future considerations

1. A primary goal of health promotion is to motivate individuals to make positive life-style changes. 2. Health promotion is multifaceted and each company must select the most appropriate method(s) of intervention for their employees. 3. In any company, a successful health promotion program requires an advocate or champion who functions as the initiator and leader for program development. Employee involvement, from inception to ongoing development of all programs, is also necessary for success. 4. To positively impact health care costs, health promotion programs should be well planned, well timed, and appropriately marketed. Needs of all workers (i.e., blue collar, minorities) should be considered.

Using audit in a district-wide management system

As a consequence of the NHS reforms, the budgeting and competitive tendering of clinical services between districts requires accurate accumulation of data. John Mosley and Roger Fairbanks describe how data obtained by clinicians from their own audit has been used to construct a casemix solution that provides the necessary financial information for a district.

Has outpatient quality assurance improved performance?

A prospective study of the outpatient department was undertaken as part of a quality assurance initiative to improve patient care. Senior managers and clinicians set realistic performance targets for attendances, availability of records, waiting times and delay in correspondence to general practitioners. From February 1989 to January 1990, performance was analysed each month, and data and subsequent management changes publicised. The results show improvements in all areas studied, which supports the generally held belief that clinicians wish to improve the care offered to patients.

Bones, blood, pellets, glass, and no body

A man was found guilty of killing his wife, although her body was never found. The case centered on her car, which contained fragments of bone, glass, shotgun pellets, and dried blood. Deoxyribonucleic acid (DNA) fingerprinting techniques were used to establish the decedent's identity. Examination of the bone fragments revealed that they were from the skull. These two pieces of information, added to other evidence, proved that the defendant's wife had received a fatal injury in her car, and a guilty verdict was rendered.

Prescription for a system

Health authorities' drug budgets are large and difficult to control. Alan Willson and colleagues outline the system requirements for audit, resource management and costing reports.

Data communications within a health authority

This paper describes the data communication network installed in four hospitals in the Hammersmith and Queeen Charlotte's Special Health Authority to support several hundred microcomputers, terminals and printers and several host systems, including the integrated computerized hospital information system which is currently under development. Broadband local area network and wide area network technologies have been employed to provide a flexible system, which is capable of being expanded to meet the increasing demand for data communications within the authority. The broadband networks are the first such installations in a health authority in Britain.

Effect of levamisole on the clinical and immunologic responses to oral vaccine of Treponema hyodysenteriae

Conventionally raised crossbred Hampshire pigs were vaccinated orally with attenuated Treponema hyodysenteriae in combination with an anthelmintic, levamisole or dichlorvos. Pigs in group I (n = 9) were treated with levamisole and vaccinated with attenuated T hyodysenteriae and those in group II (n = 9) were treated with levamisole and permitted to commingle (contact exposure) with group I. Pigs in group III (n = 9) were vaccinated in a similar manner and were treated with dichlorvos. Pigs in group IV (n = 9) were treated with dichlorvos and permitted to commingle with group III. Control pigs (group V; n = 9) were not given any anthelmintic, nor were they vaccinated; they were housed separately. During the 8-week interval between vaccination and challenge inoculation, 4 total days and 8 total days of diarrhea were observed in pigs in groups I and II, respectively. Likewise, 5 total days and 10 total days of diarrhea were seen in groups III and IV, respectively. In all groups, the pigs tended to shed the organism in their feces after they were vaccinated or challenge inoculated, as determined by a fluorescent antibody technique (FAT) and culture procedure (CP). Overall mean shedding patterns of 5.5% and 24.5% identified by CP and FAT, respectively, were seen in the 2 levamisole-treated groups (I and II). In contrast, mean shedding patterns of 4% and 18% of the isolation attempts were detected by CP and FAT, respectively, in the 2 dichlorvos-treated groups. Diarrhea and shedding of T hyodysenteriae in the controls (group V) did not occur.(ABSTRACT TRUNCATED AT 250 WORDS)

Field dependence in the institutionalized elderly

The institutional-inducement hypothesis of field dependence regression in the elderly was assessed by administering the Children's Embedded Figures Test (CEFT) to a group of elderly upon admission to a nursing home and to a group of community-living elderly. Both groups were retested four months later. The institutionalized group exhibited significantly lower CEFT scores on initial testing than the community-living group. In addition, the CEFT scores for the institutionalized group declined significantly from pretest to posttest. The results suggested that greater field dependence in the institutionalized elderly may be due to pre-institutional dependence regression that continues after institutionalization. Additional measures of mental status and activity levels were also lower in the institutionalized group upon admission supporting a pre-institutional generalized regression effect.

Occupational risk of hepatitis B infection in hospital workers

To estimate the risk of hepatitis B virus (HBV) infection among hospital workers, we measured the prevalence of HBV infection in employees in five hospitals in different parts of the country and examined the effect of occupational and non-occupational factors on HBV prevalence. Among 5,697 persons studied, serologic markers of HBV infection were found in 807 (14%). Prevalence of infection was strongly related to race (Asian greater than Black greater than White), sex (male greater than female) and increasing age. Risk related to health occupation, studied by examining the change in HBV prevalence with duration in occupational group, was most strongly correlated with frequency of contact with blood during work. Workers having frequent blood contact had the highest estimated infection rate (1.05 per 100 person-years) and those with moderate contact an intermediate infection rate, compared to a negligible infection rate in workers with no blood contact. Frequency of needle accidents had an independent, positive effect on HBV infection rates, while degree of patient contact had no effect. Infection risk was uniform among all hospitals for groups with frequent blood contact. Among different occupation groups, risk of HBV infection also correlated closely with degree of blood-needle contact during daily work. This study provides a general approach to assessing risk of HBV infection in hospital personnel, and indicates that risk may be most easily estimated by quantitating degree of blood-needle contact during daily work.

A computer-based laboratory record system in an endocrinology laboratory

A computer-based system for maintaining cumulative laboratory result records is described. The system is also intended to help in the organisation of laboratory work schedules. The system has been in use for over a year and has proved to be successful in improving the service offered by the laboratory.

Hepatitis B infection in pediatric dialysis and transplant patients: significance of e antigen

We examined the clinical significance of hepatitis Be antigenemia in 36 HBsAg positive pediatric dialysis and renal transplant patients. One hundred twenty-seven sera were tested for HBeAg and anti-HBe. Seventy-three sera (57%) from 29 patients (81%) contained HBeAg. The presence of HBeAg was associated with an increased titer of HBsAg (P < 0.005) and with the presence of the HBsAg carrier state (P < 0.001). HBeAg was found in 40% of specimens taken from dialysis patients, and in 70% of specimens from transplant patients (P < 0.001). No serum contained anti-HBe, although 28 of 29 sera (97%) tested had antibody to HBcAg. No association was found between the presence of HBeAg and serum aminoleucine transferase levels or the histologic evidence of chronic active hepatitis. Fifteen HBeAg negative sera from patients persistently positive for HBsAg were tested for HBV-specific DNA polymerase activity; 7 (47%) had significant activity. Since both HBeAg and DNA p are indicators of infectivity, many HBeAg negative sera from immunosuppressed HBsAg carriers may be infectious.

[Hepatitis A antibodies in children]

With the finding of HBV and HAV, it is possible at the present time to recognize according to its etiology three types of viral hepatitis: type A, Type B and type non-A-non-B. In this paper we have proved that a low socioeconomic status plays a very important role in the spreading of this disease. In a community with a low socioeconomic status, of forty children attending the fourth grade of a primary school, 97 percent were found to have anti-HA: while in a similar group of children with a higher socioeconomic background, we found only 40 per cent of positive cases. A positive sero convertion to anti-HA was found in 90 per cent of the 73 children with acute hepatitis; the remaining 10 per cent were non-A-non-B. A group of 61 children admitted to the L. Calvo Mackenna Children's Hospital with acute or chronic non hepatic disease were studied for anti-HA. We found 77% positive cases in the group of infants under 4 months old; in older infants, a low incidence of anti-HA was observed, but a notorious increase of positive cases was seen after the age of two years, reaching 100 percent of positive cases in children above four years of age. In ten patients studied with prolonged hepatitis, five of them could be possibly classified as having a non-A-non-B hepatitis.

Spline function analysis applied to a human placental lactogen assay

A mathematical procedure for calculating radioimmunoassay calibration curves is described. The application of this method to a human placental lactogen assay is discussed, and the results obtained are compared with those from other methods of analysis.

Stimulation of the proliferation of cortical neurons by prenatal treatment with growth hormone

Subcutaneous or intravenous injections daily of purified bovine pituitary growth hormone into pregnant rats from the 7th till the 20th day of pregnancy (total dose 36 mg) resulted in offspring with unchanged body weight but with significant increases in brain weight, brain DNA content, cortical cell density, and ratio of neurons to glia.