The Pitfalls of Abnormal Laboratory Value Interpretation in Vaccine Clinical Trials: The Example of Asymptomatic Transient Neutropenia

Hematological and clinical chemistry measurements are an integral part of vaccine safety monitoring. While adopting a conservative approach is important to exclude potential risks for patients, the rationale and methodology underlying the assessment of given adverse events have to be well grounded to avoid raising unfounded concerns. Using asymptomatic transient neutropenia as an example, this paper aims to address the complexity of interpreting abnormal hematological values in vaccine clinical trials and to evaluate the validity of using neutrophil count cut-off points to assess neutropenia in the context of safety monitoring. The validity of the neutrophil count cut-off point methodology was assessed in terms of content validity (i.e., the extent to which a single neutrophil count below the cut-off point corresponds to a clinically significant adverse event), criterion validity (i.e., the extent to which a neutrophil count below a given cut-off point correlates with another manifestation of neutropenia, namely bacteremia), and construct validity (i.e., the exactness of the assumption that a neutrophil count below a given cut-off point corresponds to a reactogenic event caused by the vaccination). We argue that, because of within-individual physiological fluctuations, variations according to population demographics, and poor predictive potential with regard to neutropenia-associated infection, the application of the cut-off point methodology to neutropenia safety monitoring presents major limitations. Based on this assessment, we conclude that hematological laboratory values must be evaluated on a case-by-case basis by investigators to determine their clinical significance.

A simple explanation for declining temperature sensitivity with warming

Recently, multiple studies have reported declining phenological sensitivities (∆ days per ℃) with higher temperatures. Such observations have been used to suggest climate change is reshaping biological processes, with major implications for forecasts of future change. Here, we show that these results may simply be the outcome of using linear models to estimate nonlinear temperature responses, specifically for events that occur after a cumulative thermal threshold is met-a common model for many biological events. Corrections for the nonlinearity of temperature responses consistently remove the apparent decline. Our results show that rising temperatures combined with linear estimates based on calendar time produce the observations of declining sensitivity-without any shift in the underlying biology. Current methods may thus undermine efforts to identify when and how warming will reshape biological processes.

Efficacy, safety, and immunogenicity of the Shigella sonnei 1790GAHB GMMA candidate vaccine: Results from a phase 2b randomized, placebo-controlled challenge study in adults

BACKGROUND

Shigellosis accounts for substantial morbidity and mortality worldwide and is the second most common cause of moderate and severe diarrhoea in children.

METHODS

This phase 2b study (NCT03527173), conducted between August 2018 and November 2019, evaluated vaccine efficacy (VE), safety, and immunogenicity of a Shigella sonnei GMMA candidate vaccine (1790GAHB) in adults, using a S. sonnei 53 G controlled human infection model. Participants (randomized 1:1) received two doses of 1790GAHB or placebo (GAHB-Placebo), at day (D) 1 and D29, and an oral challenge of S. sonnei 53 G at D57. VE was evaluated using several endpoints, reflecting different case definitions of shigellosis. For the primary endpoint, the success criterion was a lower limit of the 90% confidence interval >0.

FINDINGS

Thirty-six and 35 participants received 1790GAHB or placebo, respectively; 33 and 29 were challenged, 15 and 12 developed shigellosis. VE was not demonstrated for any endpoint. Adverse events were more frequent in 1790GAHB versus placebo recipients post-vaccination. Anti-S. sonnei lipopolysaccharide (LPS) IgG responses increased at D29 and remained stable through D57 in group 1790GAHB; no increase was shown in placebo recipients.

INTERPRETATION

1790GAHB had an acceptable safety profile and induced anti-LPS IgG responses but did not demonstrate clinical efficacy against shigellosis. Baseline/pre-challenge antibody levels were higher in participants who did not develop shigellosis post-challenge, suggesting a role of anti-LPS IgG antibodies in clinical protection, although not fully elucidated in this study. For further vaccine development an increased S. sonnei O-antigen content is likely needed to enhance anti-LPS immune responses.

FUNDING

GlaxoSmithKline Biologicals SA, Bill and Melinda Gates Foundation.

Vaccine Production in Africa: A Feasible Business Model for Capacity Building and Sustainable New Vaccine Introduction

Africa has the highest incidence of mortality caused by infectious diseases, and remarkably does not have the capacity to manufacture vaccines that are essential to reduce mortality, improving life expectancy, and promoting economic growth. GAVI has significantly helped introduction of new vaccines in Africa but its sustainability is questionable, and new vaccines introduction post-graduation is rare. Conversely, Africa with its high population and economy growth is an increasing potential market for vaccines. This study aimed to investigate how investment for vaccine production in Africa could be triggered and in which way it could be affordable to most African governments or investors. The investigation was based on a literature review and supplemented by online questionnaires directed to global vaccine stakeholders, African governments and regulatory authorities. In-depth interviews with experts in manufacturing capacity implementation and regulatory capacity building in Africa complemented the study. We also developed business plan scenarios including facility costs calculations and a possible investment plan based on expert opinions and publicly available information from pertinent sources. We saw that, governments in Africa, show interest in vaccine production establishments but only with external support for investment. The common regulatory functionality gap was the quality control laboratories to test vaccine lots before regulatory release. The global vaccine stakeholders showed less preference in investment for vaccine production establishment in Africa. The diverse political ambitions among African governments make it difficult to predict and access the market, a prerequisite for competitive production. A feasible solution could be a small production facility that would use technologies with high yield at low costs of goods to cover the regional needs. A respective antigen production facility is estimated to cost USD 25 Million, an affordable dimension for investors or interested African governments. Attractiveness for the African market is deemed to be high when targeting diseases almost exclusively for Africa (e.g., malaria or invasive non-typhoidal salmonella). With a smart 5 years tangible implementation plan, marketing agreements within existing regional collaborations and with a strong political will, an African government alone or together with an investor could convince global vaccine stakeholders and investors to support.

Booster Vaccination With GVGH Shigella sonnei 1790GAHB GMMA Vaccine Compared to Single Vaccination in Unvaccinated Healthy European Adults: Results From a Phase 1 Clinical Trial

The investigational Shigella sonnei vaccine (1790GAHB) based on GMMA (generalized modules for membrane antigens) is immunogenic, with an acceptable safety profile in adults. However, pre-vaccination anti-S. sonnei lipopolysaccharide (LPS) antibody levels seemed to impact vaccine-related immune responses. This phase 1, open-label, non-randomized extension study (ClinicalTrials.gov: NCT03089879) evaluated immunogenicity of a 1790GAHB booster dose in seven adults with undetectable antibodies prior to priming with three 1790GAHB vaccinations 2–3 years earlier (boosted group), compared to one dose in 28 vaccine-naïve individuals (vaccine-naïve group). Anti-S. sonnei LPS serum IgG geometric mean concentrations and seroresponse (increase of ≥25 EU or ≥50% from baseline antibody ≤ 50 EU and ≥50 EU, respectively) rates were calculated at vaccination (day [D]1), D8, D15, D29, D85. Safety was assessed. Geometric mean concentrations at D8 were 168 EU (boosted group) and 32 EU (vaccine-naïve group). Response peaked at D15 (883 EU) and D29 (100 EU) for the boosted and vaccine-naïve groups. Seroresponse rates at D8 were 86% (boosted group) and 24% (vaccine-naïve group) and increased at subsequent time points. Across both groups, pain (local) and fatigue (systemic) were the most frequent solicited adverse events (AEs). Unsolicited AEs were reported by 57% of boosted and 25% of vaccine-naïve participants. No deaths, serious AEs, or AEs of special interest (except one mild neutropenia case, possibly vaccination-related) were reported. One 1790GAHB dose induced a significant booster response in previously-primed adults, regardless of priming dose, and strong immune response in vaccine-naïve individuals. Vaccination was well tolerated.

A Phase 2a Randomized Study to Evaluate the Safety and Immunogenicity of the 1790GAHB Generalized Modules for Membrane Antigen Vaccine against Shigella sonnei Administered Intramuscularly to Adults from a Shigellosis-Endemic Country

Shigellosis is a mild-to-severe diarrheal infection, caused by the genus Shigella, and is responsible for significant morbidity and mortality worldwide. We evaluated the safety and immunogenicity of an investigational Shigella sonnei vaccine (1790GAHB) based on generalized modules for membrane antigens (GMMA) in Kenya, a Shigella-endemic country. This phase 2a, observer-blind, controlled randomized study (NCT02676895) enrolled 74 healthy adults aged 18–45 years, of whom 72 were vaccinated. Participants received, in a 1:1:1 ratio, two vaccinations with the 1790GAHB vaccine at doses of either 1.5/25 μg of O antigen (OAg)/protein (group 1.5/25 μg) or 5.9/100 μg (group 5.9/100 μg) at day (D) 1 and D29, or vaccination with a quadrivalent meningococcal vaccine at D1 and tetanus, diphtheria, and acellular pertussis vaccine at D29 (control group). Solicited and unsolicited adverse events (AEs), serious AEs (SAEs), and AEs of special interest (neutropenia and reactive arthritis) were collected. Anti-S. sonnei lipopolysaccharide (LPS) serum immunoglobulin G (IgG) geometric mean concentrations (GMC) were evaluated at D1, D29, and D57 and compared to anti-S. sonnei LPS antibody levels in convalescent patients naturally exposed to S. sonnei. The percentages of participants with seroresponse were also calculated. The most frequently reported solicited local and systemic AEs across all groups were pain and headache, respectively. Only one case of severe systemic reaction was reported (severe headache after first vaccination in group 5.9/100 μg). Seven and three episodes of neutropenia, assessed as probably or possibly related to vaccination respectively, were reported in the investigational and control groups, respectively. No other SAEs were reported. Despite very high baseline anti-S. sonnei LPS serum IgG levels, the 1790GAHB vaccine induced robust antibody responses. At D29, GMC increased 2.10- and 4.43-fold from baseline in groups 1.5/25 and 5.9/100 μg, respectively, whereas no increase was observed in the control group. Antibody titers at D57 were not statistically different from those at D29. Seroresponse was 68% at D29 and 90% at D57 in group 1.5/25 μg, and 96% after each vaccination in group 5.9/100 μg. The 1790GAHB vaccine was well tolerated and highly immunogenic in a population of African adults, regardless of the GMMA OAg/protein content used.

Developmental dyscalculia: prevalence and prognosis

The prevalence of developmental dyscalculia (DC) in the school population ranges from 3-6 %, a frequency similar to that of developmental dyslexia and ADHD. These studies fulfilled the criteria for an adequate prevalence study, i.e., were population based, using standardized measures to evaluate arithmetic function. Although the variation in prevalence is within a narrow range, the differences are probably due to which definition of dyscalculia was used, the age the diagnosis was made and the instrument chosen to test for DC. The relative predominance of girls with DC may reflect a greater vulnerability to environmental influences alone or in addition to a biological predisposition. DC is not only encountered as a specific learning disability but also in diverse neurological disorders, examples of which include ADHD, developmental language disorder, epilepsy, treated phenylketonuria and Fragile X syndrome. Although the long-term prognosis of DC is as yet unknown, current data indicate that DC is a stable learning disability persisting, at least for the short term, in about half of affected children. The long-term consequences of DC and its impact on education, employment and psychological well-being have yet to be determined.

Economic deprivation and AIDS incidence in Massachusetts

OBJECTIVES

This study quantified AIDS incidence in Massachusetts in relation to economic deprivation.

METHODS

Using 1990 census block-group data, 1990 census population counts, and AIDS surveillance registry data for the years 1988 through 1994, we generated yearly and cumulative AIDS incidence data for the state of Massachusetts stratified by sex and by neighborhood measures of economic position for the total, Black, Hispanic, and White populations.

RESULTS

Incidence of AIDS increased with economic deprivation, with the magnitude of these trends varying by both race/ethnicity and sex. The cumulative incidence of AIDS in the total population was nearly 7 times higher among persons in block-groups where 40% or more of the population was below the poverty line (362 per 100,000) than among persons in block-groups where less than 2% of the population was below poverty (53 per 100,000).

CONCLUSIONS

Observing patterns of disease burden in relation to neighborhood levels of economic well-being elucidates further the role of poverty as a population-level determinant of disease burden. Public health agencies and researchers can use readily available census data to describe neighborhood-level socioeconomic conditions. Such knowledge expands options for disease prevention and increases the visibility of economic inequality as an underlying cause of AIDS.

A role for norepinephrine in stress-induced cognitive deficits: alpha-1-adrenoceptor mediation in the prefrontal cortex

BACKGROUND

Stress exacerbates many neuropsychiatric disorders associated with prefrontal cortical (PFC) dysfunction. Stress also impairs the working memory functions of the PFC. Although stress research has focused on dopaminergic mechanisms, stress also increases norepinephrine (NE) release in PFC, and intra-PFC infusions of NE alpha-1-adrenoceptor agonists impair working memory. The current study examined whether NE alpha-1-adrenoceptor actions in PFC contribute to stress-induced deficits in working memory performance.

METHODS

Rats were treated with a pharmacological stressor, FG7142 (30 mg/kg) or vehicle 30 min before testing on a test of spatial working memory, delayed alternation. The alpha-1-adrenoceptor antagonist, urapidil (0.1 microgram/0.5 microL), or saline vehicle, was infused into the PFC 15 min before delayed alternation testing.

RESULTS

As observed previously, FG7142 significantly impaired the accuracy of delayed alternation performance, and induced a perseverative pattern of responding consistent with PFC dysfunction. FG7142 also slowed motor response times. Infusion of urapidil into the PFC completely reversed the FG7142-induced impairment in delayed alternation performance, but did not alter the slowed motor responding.

CONCLUSIONS

These findings indicate that alpha-1-adrenoceptor stimulation in the PFC contributes to stress-induced impairments in PFC cognitive functions. These neurochemical actions may contribute to symptoms of working memory impairment, poor attention regulation, or disinhibited behaviors in neuropsychiatric disorders sensitive to stress exposure.

Syndrome dimensions of the child behavior checklist and the teacher report form: a critical empirical evaluation

The construct representation of the cross-informant model of the Child Behavior Checklist (CBCL) and the Teacher Report Form (TRF) was evaluated using confirmatory factor analysis. Samples were collected in seven different countries. The results are based on 13,226 parent ratings and 8893 teacher ratings. The adequacy of fit for the cross-informant model was established on the basis of three approaches: conventional rules of fit, simulation, and comparison with other models. The results indicated that the cross-informant model fits these data poorly. These results were consistent across countries, informants, and both clinical and population samples. Since inadequate empirical support for the cross-informant syndromes and their differentiation was found, the construct validity of these syndrome dimensions is questioned.

Dopamine D4 receptor (D4DR) and serotonin transporter promoter (5-HTTLPR) polymorphisms in the determination of temperament in 2-month-old infants

We and others have previously shown that the dopamine D4 exon III repeat (D4DR) and the serotonin-transporter promoter region (5-HTTLPR) polymorphisms are not only associated with adult personality traits1-7 but also with temperament in 2-week-old neonates.8 We now report the results of a second study of these infants and their temperament at 2 months using Rothbart's Infant Behavior Questionnaire (IBQ).9 There were significant negative correlations between neonatal orientation and motor organization as measured by the Neonatal Behavioral Assessment Scale (NBAS)10 at 2 weeks and negative emotionality, especially distress in daily situations, at 2 months of age. There were significant main effects for negative emotionality and distress when the infants were grouped by the D4DR and the 5-HTTLPR polymorphisms. Infants with long D4DR alleles had significantly lower scores on Negative Emotionality (F[1, 72] = 8.50, P = 0.005) and Distress to Limitations (F[1,72] = 4.93, P = 0.03) than infants with short D4DR alleles. In contrast, infants with the short homozygous (s/s) 5-HTTLPR genotype had higher scores on Negative Emotionality (F[1,72] = 3.88, P = 0.053) and Distress to Limitations (F[1,72] = 4.94, P = 0.029) than infants with the I/s or I/I genotypes. The strongest effects occurred in those infants with the s/s 5-HTTLPR polymorphism who also were lacking long D4DR alleles which in some studies has been linked to adult novelty seeking.1,6 These infants showed most negative emotionality and most distress to daily situations, temperament traits that are perhaps the underpinning of adult neuroticism.

Persistence of developmental dyscalculia: what counts? Results from a 3-year prospective follow-up study

OBJECTIVE

To study the natural history of developmental dyscalculia (DC), a specific learning disability affecting approximately 5% of the normal school age population and to identify factors that contribute to persistence.

STUDY DESIGN

Of a cohort of 3029 fourth-grade students, 185 children were classified as having DC; 140 participated in phase 1 in which they underwent IQ testing; arithmetic, reading, and writing evaluations; and an assessment for attention-deficit/hyperactivity disorder over a 3-year period. Three years later (phase 2), 88% of the children (123 of 140) were retested.

RESULTS

The arithmetic scores of 95% of the 123 children with DC fell within the lowest quartile for their class. At phase 2, 47% (57 of 123) of the children were reclassified as having persistent DC, scoring in the lowest 5% for their age group (13 to 14 years old). Factors significantly associated with persistence of DC in a multivariate model were severity of the arithmetic disorder and arithmetic problems in siblings of the probands. Factors that were not associated with persistence included socioeconomic status, gender, the presence of another learning disability, and educational interventions.

CONCLUSIONS

The outcome of DC is similar to that of other learning disabilities, with a persisting course in almost half of affected children; the remainder continue to perform poorly in arithmetic. The ultimate outcome of children with dyscalculia and the effect on education, employment, and psychologic well-being have yet to be determined.

Dopamine D4 receptor and serotonin transporter promoter in the determination of neonatal temperament

Genetic effects on behavior were evaluated at a time in early development when we hypothesized that environmental influences are minimal and least likely to confound associations between temperament and genes. The behavioral effects of two common polymorphisms linked respectively in some, but not all, studies to novelty seeking (dopamine D4 receptor-D4DR) and neuroticism and harm avoidance (serotonin transporter promoter region-STPR) were examined in a group of 81 two-week-old neonates. Neonate temperament was evaluated using the Brazelton neonatal assessment scale (NBAS). Multivariate tests of significance showed a significant association of D4DR across four behavioral clusters pertinent to temperament including orientation, motor organization, range of state and regulation of state. A significant multivariate interaction was also observed between D4DR and STPR. The effect of the homozygous short STPR genotype (s/s) was to lower the orientation score for the group of neonates lacking the long form (L) of D4DR. When adult subjects were grouped by the STPR polymorphism there is no significant effect of L-D4DR in those subjects homozygous for the STPR short form (s/s) whereas in the group without the homozygous genotype the effect of L-D4DR is significant and accounts for 13% of the variance in novelty seeking scores between groups.

A community based study of failure to thrive in Israel

OBJECTIVE

To examine the characteristics of infants suffering from failure to thrive in a community based cohort in Israel and to ascertain the effect of failure to thrive on their cognitive development.

METHODS

By review of records maintained at maternal and child health clinics in Jerusalem and the two of Beit Shemesh, epidemiological data were obtained at age 15 months on a cohort of all babies born in 1991. For each case of failure to thrive, a matched control was selected from the same maternal and child health clinic. At age 20 months, cognitive development was measured, and at 25 months a home visit was carried out to assess maternal psychiatric status by questionnaire, and the HOME assessment was performed to assess the home environment.

RESULTS

3.9% of infants were found to have fallen below the third centile in weight for at least three months during the first year of life. Infants with failure to thrive did not differ from the general population in terms of obstetric or neonatal complications, birth order, or parents' ethnic origin, age, or years of education. The infants with failure to thrive did have lower birthweights and marginally smaller head circumferences at birth. Developmental assessment at 20 months of age showed a DQ of 99.7 v 107.2 in the matched controls, with 11.5% having a DQ below 80, as opposed to only 4.6% of the controls. No differences were found in maternal psychiatric problems as measured by a self report questionnaire. There were, however, significant differences in subscales of the HOME scale.

CONCLUSIONS

(1) Infants who suffered from failure to thrive had some physiological predispositions that put them at risk; (2) failure to thrive may be an early marker of families providing suboptimal developmental stimulation.

The potential impact of health care reform on public health HIV-related activities

This article observes that, despite the clear potential benefits of health care reform's expanding health insurance coverage for people with human immunodeficiency virus (HIV) disease, there is a real danger of losing existing acquired immunodeficiency syndrome (AIDS) services if federal categorical public health programs are cut. It discusses the considerable accomplishments of the Ryan White CARE Act and of Centers for Disease Control and Prevention (CDC) prevention funding. The funding for these current efforts will not be assumed by near universal insurance coverage for a variety of reasons, including the need to care for populations who are neglected by health care reform, to continue services unlikely to be reimbursable, and to offer care in a range of locations other than licensed health care facilities.

Developmental dyscalculia behavioral and attentional aspects: a research note

Behavioral characteristics of 140 children with developmental dyscalculia (DC) were evaluated using the Child Behavior Checklist. DC children demonstrated more behavior problems than normal children but significantly fewer problems than children psychiatrically referred. DC children had significantly more attentional problems although they had normal levels of anxiety/depression. Significantly higher scores on all syndrome scales were found for DC children who had attentional problems in the clinical range. When associated with dyslexia and a low verbal IQ, DC children had more attentional problems and externalizing syndromes. The implications of the behavioral characteristics of DC are discussed.

[Typing of 17 porcine enterovirus isolates from polio encephalomyelitis cases during the years 1983-1991]

Seventeen strains of porcine enteroviruses (PEV) were isolated from organs of 119 pigs with symptoms of polioencephalomyelitis submitted to the State Veterinary Institute Arnsberg/Westphalia between 1983 and 1991. 15 isolates originated from the central nervous system and 2 from organ suspensions made up of a brain-spleen-pool and a lung-spleen-lymph node-pool, respectively. Isolates were assigned to 7 PEV types which were present at the following frequencies: PEV1: 2x; PEV2: 6x; PEV4: 3x; PEV5: 1x; PEV6: 2x; PEV 12: 1x; PEV 13: 2x. Mortality rates of affected groups exhibited an age-dependent curvilinear relationship suggesting that the PEV involved possessed a rather similar low to medium grade neurovirulence, irrespective of type. Exceptions were 1 herd with 100% mortality at the age of 10-18 weeks from which PEV2 strain 6793/83 was isolated (described earlier) and a second herd with 18% mortality at the age of 14-18 weeks from which PEV types 1, 2 and 4 were recovered. Sensitivity of 5 cell lines for the isolation of PEV was compared. Rates of isolation from organ suspensions which had proved positive in any of the cell lines tested were as follows: PS-EK: 77%; IB-RS-2: 63%; ST: 56%; PK-15: 47%; BHK21 (CT): 10%.

Grouping of porcine enteroviruses by indirect immunofluorescence and description of two new serotypes

Porcine enteroviruses (PEV) types 1-11 were assigned to three serologic groups by indirect immunofluorescence (IIF). Serotype group I consists of PEV types 1-7 and 11 and is correlated with CPE-type I. Serotype group II is represented by PEV type 8, producing CPE-type II, while PEV types 9 and 10 are classified as serotype group III and cause CPE-type III. Three PEV isolates from the central nervous system of pigs with polioencephalomyelitis were assigned to serotype group I by IIF but to none of the established 11 serotypes by cross-neutralization. It is concluded that these isolates are representatives of two new PEV types for which the designation PEV12 and 13 is suggested.

A protocol conversion software toolkit

This paper describes a “toolkit” (a software function library) for synthesizing conversions between different transport interfaces. The method employed involves classifying these interfaces according to their “transport abstraction type.” Each actual interface is converted to or from a canonical form depending on its type, and the library also contains sufficient “abstraction converters” to convert between all of the canonical forms. The overall conversion is accomplished by combining some number of elementary conversions which execute in series. The paper describes the toolkit, contrasts it with other approaches, and shows how it can be used to solve various problems in protocol conversion and the “migration” of distributed services to new network contexts.

Familial risk of dementia associated with a biologic subtype of Alzheimer's disease

Increased platelet membrane fluidity is a stable familial trait that identifies a prominent subgroup of patients with Alzheimer's disease. Patients in this subgroup have distinct clinical features, including an early age at symptomatic onset and a rapidly progressive course. The morbid risk of Alzheimer's-type dementia was studied in 421 first-degree relatives of 43 patients who met current consensus criteria for probable Alzheimer's disease and 47 healthy controls. Relatives of patients showed an approximate 50% (90- to 95-year) lifetime risk of dementia, regardless of the platelet membrane phenotype of the respective proband, which was over four times the control value. However, relatives of patients with increased platelet membrane fluidity who developed dementia exhibited symptoms significantly earlier than relatives of patients with normal platelet membrane fluidity. Alternative genetic models that describe the relationship of platelet membrane fluidity and Alzheimer's disease are discussed.

Risk of dementia in relatives of patients with Alzheimer's disease

Using a family history questionnaire, we investigated the occurrence of dementia among relatives of patients with a clinical diagnosis of Alzheimer's disease (AD) and among the relatives of age-matched control subjects. Cumulative lifetime risk of developing AD-type dementia was greater among relatives of AD probands and was consistent with an autosomal dominant genetic mode of transmission. Although the lifetime risk of AD-type dementia was similar among relatives of early-onset and late-onset AD probands, relatives of early-onset probands tended to have an earlier onset of dementia than did relatives of late-onset AD probands. This result raises the possibility that age at onset of dementia in AD may be genetically determined.

Role of the Xis protein of bacteriophage lambda in a specific reactive complex at the attR prophage attachment site

Phage lambda controls its integration and excision by differential catalysis of the forward and reverse reactions. The lambda Int protein is required for both directions, but Xis for excision only. Previous electron microscopic observations have shown that Int protein forms a stable, condensed protein-DNA complex with the phage (attP) and prophage left (attL) substrate sites, but not with the host (attB) or prophage right (attR) sites. We have found that Int and Xis together produce a stable, condensed complex with attR. The attR complex involves the P region DNA to the left of the crossover point (O site). In contrast, the attP complex includes DNA on both sides of the crossover point (P and P'), and the attL structure involves the P' DNA to the right of O. In the presence of Int and Xis, the attL and attR sites form a paired structure. We conclude that the role of Xis is to provide a distinct reactive structure at attR, allowing attL and attR to pair efficiently.

Infants at risk for schizophrenia. The Jerusalem Infant Development Study

The development of infants born to parents with serious mental disorders was followed up from birth through the first year of life. An individual-differences approach to statistical analysis. Multidimensional Scalogram Analysis (MSA), was shown to be an effective statistical procedure for examining heterogeneous psychiatric populations. The MSA revealed the existence of a subgroup of infants born to schizophrenics who repeatedly performed poorly in motor and sensorimotor areas of functioning during their first year of life. These infants were especially vulnerable to external insults, and many had low to low-normal birth weights. These findings, taken together with similar findings from other investigations, add support to the hypothesis that these infants may have a genetically determined neurointegrative deficit.

Amplification of single-strand DNA binding protein in Escherichia coli

An E. coli strain containing a recombinant plasmid carrying the E. coli ssbA+ gene has been shown to produce 12 to 15 fold increased amounts of single-strand DNA binding-protein relative to wild-type strains. In addition, a gamma transducing phage carrying the E. coli uvrA+ gene has been shown to also carry the ssbA+ gene and to be capable of producing increased amounts of binding protein.

The isolation and genetic characteristics of lambda transducing phages of the uvrA+ and uvrC+ genes of E. coli K12

Lambda transducing phages carrying the excision repair genes uvrA+ and uvrC+ were selected from a pool of lambda phages carrying EcoR1 fragments of E. coli DNA. These phages and also lambdauvrB+ (obtained from Gottesman) were used to make lysogens of excision-defective strains carrying uvrA-, uvrB- or uvrC-. Lambda uvrA+ was found to transduce strains carrying uvrA- but not those carrying uvrB- or uvrC-, to normal ultraviolet resistance. Similarly, lambdauvrB+ and lambdauvrC+ were found to complement only the corresponding uvr- allele. The lambda transducing phages were co-transduced with gal+ by P1 phage into lysogenic gal- recipients, and presumably were integrated at the normal prophage site.