Development and evaluation of candidate recombinant Salmonella-vectored Salmonella vaccines.

Attenuated Salmonella Enteriditis (ΔSE) recombinant vaccine vectors incorporating a Salmonella flagellar filament protein (fliC) subunit, a putative cell-mediated epitope, for expression of the lamB gene (encoding a maltose outer membrane porin), with or without co-expression of a putative immune-enhancing CD154 oligopeptide, were developed and compared with wild-type Salmonella Enteriditis (experiments 1 and 2) or the attenuated ΔSE empty vector (experiment 3) as initial vaccine candidates against Salmonella infection. A total of 3 experiments were performed to assess the infection and clearance rate of each of these constructs. Each construct or Salmonella Enteriditis was orally administered to broiler chicks at day of hatch by oral gavage (~10(8) cfu/chick). In experiments 1 to 3, liver-spleen and cecal tonsils were removed aseptically for recovery of wild-type Salmonella Enteriditis or ΔSE mutants. These experiments suggested that cell surface expression of fliC alone markedly increased the clearance rate of the vector at or before 21d postvaccination in all 3 experiments. In a fourth experiment, broilers were vaccinated with one of the vaccine constructs or the ΔSE empty vector and then challenged with wild-type Salmonella Typhimurium. At 19 d posthatch, 16 d postinfection, neither candidate protected against challenge significantly better than the ΔSE empty vector, although there was significantly less Salmonella recovered from vaccinated chickens as compared with nonvaccinated controls. These experiments indicate that these experimental vaccines did not protect against heterologous challenge or enhance clearance after Salmonella Typhimurium challenge; as such, their value as vaccines is limited. The increased clearance of the candidate vaccines, particularly the vector expressing fliC alone, may have value in that the fliC epitope may decrease the clearance time of other recombinant vectored Salmonella vaccines.

Development of adjustment problems in girls: what syndromes emerge?

The development of a broad spectrum of adjustment problems in girls was studied longitudinally from late childhood to early adulthood. A specific interest concerned how well the externalizing-internalizing distinction could explain the data. The sample consisted of about 500 Swedish girls, reasonably representative of the general population. Variable-oriented methods were complemented with person-oriented methods to study syndrome formation at the level of the individual. The results suggested a rather diversified pattern of multi-problem syndromes in late childhood, whereas the syndrome structure in early adolescence was organized around a differentiation between girls with externalizing adjustment problems and girls with peer problems. An externalizing syndrome was found to be stable between late childhood and early adolescence, increasing the risk of severe maladjustment in adulthood. Internalizing problems showed no clear-cut continuity with adult maladjustment. Results are discussed in relation to the externalizing-internalizing distinction, which to some extent is called in question.

A person-oriented approach in research on developmental psychopathology.

There is a growing acceptance of a holistic, interactionistic view in which the individual is seen as an organized whole, functioning and developing as a totality. This view emphasizes the importance of patterns of operating factors. Within this framework, a standard variable-oriented approach, focusing on the variable as the main theoretical and analytical unit, has limitations. A person-oriented approach would often be preferable, where the main theoretical and analytical unit is the specific pattern of operating factors. Such an approach is presented here, focusing on individual development and psychopathology. A brief theoretical and methodological overview is given and a classification approach is emphasized. Empirical examples concerning the longitudinal study of adjustment problems illustrate a number of issues believed to be important to development and psychopathology: problem gravitation, the significance of single variables and of patterns, the developmental study of syndromes (= typical patterns), and the detection of "white spots" in development.

Measurement and data quality in longitudinal research.

The importance of paying attention to scale levels is emphasized and it is pointed out that Steven's hierarchy of ratio, interval, ordinal, and nominal scales is too narrow; other important scale properties have to be considered. For instance, sometimes a carefully constructed variable on a nominal scale contains more information than a variable at a higher scale level. Direct versus indirect measurement and relative versus absolute measurement are also discussed and the effects of errors of measurement on the results are considered. It is not infrequent in a longitudinal setting to disregard sampling considerations, which can be very unfortunate. Such considerations, as well as the use of modern sampling theory, can considerably enhance the quality of a longitudinal study. Finally, a number of conclusions and recommendations are given for the carrying out of longitudinal research in relation to measurement issues.

[Acute cyanide poisoning in an infant]. / Acute blauwzuurvergiftiging bij een zuigeling.

An infant of 9 months was admitted to hospital in comatose condition; cyanide poisoning was suspected. This poisoning was caused by the desorption of hydrocyanic acid from building materials after the house had been fumigated with hydrocyanic acid under strict supervision and observed safety measures. Administration of 4-dimethyl-aminophenol, a methaemoglobin inducer, and sodium thiosulphate together with supportive measures, led to complete recovery of the infant, although the general hypotony persisted for a few weeks.

You Can't Classify All of the People All of the Time.

When performing a classification study, it is sometimes a sound strategy not to classify all subjects but to leave a residue of unclassified entities to be analyzed separately. Starting from an interactional paradigm, theoretical reasons for this approach were given. A procedure, RESIDAN, for carrying out a classification analysis using a residue was presented and empirical results for two data sets were given, both of which indicated that belonging to a residue is a property of individuals that has a significant stability over time. Although RESIDAN can be applied to data from a single measurement period, test-retest data are useful for separating subjects with true deviant patterns from subjects with deviant patterns caused by errors of measurement. It was argued that the concept of antitype (= rare pattern) has theoretical significance and could be studied within the presented framework.

Type A behavior: a longitudinal study from childhood to adulthood.

In a longitudinal study of a sample of Swedish males and females (n = 170), Type A-related behavior at age 13 was related to the scores on an abbreviated Type A scale based on JAS which was administered when the same subjects were 27 years old. Aggression, Motor Hyperactivity, Overambition, and Overachievement measured at age 13 were used as predictors in a multiple regression analysis, with Type A score at age 27 as the dependent variable. The following results were obtained: 1) for men the multiple correlation was 0.41 (p less than 0.01), with Aggression and Overambition accounting for most of the prediction, and b) for women the multiple correlation was 0.36 (p less than 0.05), with Motor Hyperactivity accounting for most of the prediction. It was concluded that Type A-related behavior could be identified rather early and that it shows an unexpected degree of stability over a period of 14 years.

Longisectional interaction structure analysis (LISA) in psychopharmacology and developmental psychopathology.

Longisectional interaction structure analysis (LISA) is a method for evaluating multivariate observations in a sample of individuals (patients) at two or more than two subsequent times (stages). It combines cross-sectional configural frequency analysis (CFA) for defining interactions between variables at a given stage with longitudinal interaction structure analysis (ISA) in relating variables observed at two subsequent stages, nonparametrically. The interactions are identified locally as types rather than globally as contingencies, where types are defined as (cross-sectional or longitudinal) patterns occurring in more individuals than expected under H0 of no (cross-sectional or longitudinal) interaction. LISA is applied to data sets from a clinical follow-up study and from a longitudinal study within developmental psychology. It is shown to be a useful technique for the interpretation of such data.

Overachievement and catecholamine excretion in an achievement-demanding situation.

We have studied the relationship between overachievement (defined as high school achievement in relation to intelligence) and catecholamine output (adrenaline and noradrenaline). The subjects were 176 children aged 13 yr. Adrenaline and noradrenaline excretions were measured in (1) a neutral situation (attending a nonexciting film), and (2) in an achievement-demanding situation. In the achievement-demanding situation, overachieving boys had much higher adrenaline excretion levels than the other boys. This difference was not found for girls. For boys, overachievement in combination with overambition (as rated by teachers) was related to a higher output of both adrenaline and noradrenaline in an achievement-demanding situation.

A Longitudinal Factor Model For Studying Change In Ability Structure.

Models of the Longitudinal Factor Analysis type were designed to describe the development of ability structure between the ages 10 and 13. The parameters of the models were estimated by the LISREL program (Jöreskog & van Thillo, 1973). The sample comprised 375 girls and 353 boys who were tested at age 10 and retested at age 13 with six ability tests and two achievement tests. The results indicate that verbal, inductive, and spatial abilities can be described as developing fairly independently of each other between the ages 10 and 13. At age 13, but not at age 10, two subfactors of the inductive factor could be differentiated. The unique variances show a marked decrease between age 10 and age 13. Consequently the factors, and the relationships between factors, explain more of the variance of the response variates at age 13 than at age 10.