Spontaneous autoimmune gastritis and hypochlorhydria are manifest in the ileitis-prone SAMP1/YitFcs mice.

SAMP1/YitFcs mice serve as a model of Crohn's disease, and we have used them to assess gastritis. Gastritis was compared in SAMP1/YitFcs, AKR, and C57BL/6 mice by histology, immunohistochemistry, and flow cytometry. Gastric acid secretion was measured in ligated stomachs, while anti-parietal cell antibodies were assayed by immunofluorescence and enzyme-linked immunosorbent spot assay. SAMP1/YitFcs mice display a corpus-dominant, chronic gastritis with multifocal aggregates of mononuclear cells consisting of T and B lymphocytes. Relatively few aggregates were observed elsewhere in the stomach. The infiltrates in the oxyntic mucosa were associated with the loss of parietal cell mass. AKR mice, the founder strain of the SAMP1/YitFcs, also have gastritis, although they do not develop ileitis. Genetic studies using SAMP1/YitFcs-C57BL/6 congenic mice showed that the genetic regions regulating ileitis had comparable effects on gastritis. The majority of the cells in the aggregates expressed the T cell marker CD3 or the B cell marker B220. Adoptive transfer of SAMP1/YitFcs CD4(+) T helper cells, with or without B cells, into immunodeficient recipients induced a pangastritis and duodenitis. SAMP1/YitFcs and AKR mice manifest hypochlorhydria and anti-parietal cell antibodies. These data suggest that common genetic factors controlling gastroenteric disease in SAMP1/YitFcs mice regulate distinct pathogenic mechanisms causing inflammation in separate sites within the digestive tract.

Effects of growth hormone on leucine absorption, intestinal morphology, and ultrastructure of the goldish intestine.

The mechanisms whereby exogenous growth hormone modulates intestinal structure and function in fish were investigated. Goldfish (Carassius auratus) were fed commercial flake diet sprayed with recombinant carp growth hormone (cGH) daily for 1 month. Control animals received food sprayed with the vehicle. After 1 month of daily feedings, body mass and length were determined, and animals were sacrificed to study intestinal characteristics. Sections of foregut were removed after determination of total gut length for measurement of leucine uptake, histology, and epithelial ultrastructure. Oral administration of cGH for 1 month resulted in a 40% increase in body mass and an 8% increase in body length above controls. Gut length was 43% greater and the gut length to body length ratio was 32% greater as a result of the cGH treatment. Feeding with cGH also resulted in a significant increase in leucine uptake and increased gut mucosal thickness. Analysis of transmission electron micrographs revealed significant increases in the microvillous height and density and epithelial surface area. The findings indicate that growth hormone added to feed may increase growth in fish, in part by significantly increasing gut length, mucosal thickness, and epithelial brush border surface area, leading to enhanced epithelial absorption.

Giardia duodenalis trophozoites isolated from a parrot (Cacatua galerita) colonize the small intestinal tracts of domestic kittens and lambs.

This study examines the ability of Giardia duodenalis trophozoites, isolated from a wild bird, to colonize the intestinal tracts of companion animals (kittens) and domestic ruminants (lambs). Trophozoites colonized the intestinal tracts of intraduodenally inoculated animals as demonstrated by increasing parasite burdens within the duodenum and jejunum and by fecal passage of cysts within 4 days post-inoculation. The pathogenesis of the trophozoites was further investigated in kittens. In these animals, infection significantly reduced jejunal brush border microvillous length and density, which resulted in a loss of overall epithelial brush border surface area. This injury was associated with the production of diarrhea in four of five infected kittens. These findings indicate that some bird species may carry G. duodenalis that represent a possible health threat to companion animals and livestock. Our results describe the first successful colonization of avian-derived G. duodenalis trophozoites in the small intestines of domestic kittens and lambs.

Giardia lamblia disrupts tight junctional ZO-1 and increases permeability in non-transformed human small intestinal epithelial monolayers: effects of epidermal growth factor.

In order to improve our understanding of the host cell-parasite interactions in giardiasis, this study assessed the effects of Giardia lamblia on epithelial permeability and tight junctional ZO-1, determined whether epidermal growth factor (EGF) may affect Giardia-induced epithelial injury, and evaluated if EGF modulates epithelial colonization by live G. lamblia trophozoites. Permeability was assessed in assays of trans-epithelial fluxes of FITC-dextran, and ZO-1 integrity was characterized by confocal laser immunofluorescence microscopy in confluent epithelial cell monolayers. G. lamblia significantly increased paracellular permeability and disrupted tight-junctional ZO-1 of a novel non-transformed human small intestinal epithelial cell line (SCBN). Pre-treatment with EGF prevented the development of these abnormalities and significantly inhibited attachment of live trophozoites to the enterocytes, independently of a direct microbiocidal action. These findings demonstrate that G. lamblia may cause intestinal pathophysiology by disrupting tight junctional ZO-1 and increasing epithelial permeability. Apical administration of EGF prevents these abnormalities, and reduces epithelial colonization by the live parasites.

Birth weight and school-age disabilities: a population-based study.

Mortality rates have declined for low birth weight and extremely low birth weight infants. Yet, the consequences of survival for these children may be adverse developmental outcomes. Few studies to date have examined school-age outcomes for these children. The participants in this study represented a population-based cohort of Florida children who were born between 1982 and 1984 and who were receiving a public school education in 1996-1997. Linkage methodology was used to establish a cohort of 267,213 children aged 12-15 years with both birth certificate and school records. Birth weights were stratified into 500-g increments beginning with

Jejunal brush border microvillous alterations in Giardia muris-infected mice: role of T lymphocytes and interleukin-6.

Intestinal colonization with the protozoan Giardia causes diffuse brush border microvillous alterations and disaccharidase deficiencies, which in turn are responsible for intestinal malabsorption and maldigestion. The role of T cells and/or cytokines in the pathogenesis of Giardia-induced microvillous injury remains unclear. The aim of this study was to assess the role of T cells and interleukin-6 (IL-6) in the brush border pathophysiology of acute murine giardiasis in vivo. Athymic nude (nu(-)/nu(-)) CD-1 mice and isogenic immunocompetent (nu(+)/nu(+)) CD-1 mice (4 weeks old) received an axenic Giardia muris trophozoite inoculum or vehicle (control) via orogastric gavage. Weight gain and food intake were assessed daily. On day 6, segments of jejunum were assessed for parasite load, brush border ultrastructure, IL-6 content, maltase and sucrase activities, villus-crypt architecture, and intraepithelial lymphocyte (IEL) infiltration. Despite similar parasitic loads on day 6, infected immunocompetent animals, but not infected nude mice, showed a diffuse loss of brush border microvillous surface area, which was correlated with a significant reduction in maltase and sucrase activities and a decrease in jejunal IL-6 concentration. In both athymic control and infected mice, jejunal brush border surface area and disaccharidases were high, but levels of tissue IL-6 were low and comparable to the concentration measured in immunocompetent infected animals. In both immunocompetent and nude mice, infection caused a small but significant increase in the numbers of IELs. These findings suggest that the enterocyte brush border injury and malfunction seen in giardiasis is, at least in part, mediated by thymus-derived T lymphocytes and that suppressed jejunal IL-6 does not necessarily accompany microvillous shortening.

The identification of early risk factors for severe emotional disturbances and emotional handicaps: an epidemiological approach.

Epidemiological methodology is used to examine the relationship between early childhood risk factors and future identification as having a Severe Emotional Disturbance or as having an Emotional Handicap (SED/EH) at age 13. Data were obtained from 1979/1980 Florida birth records that were electronically linked with 1992/1993 Florida school records. An epidemiological perspective was chosen due to its ability to model both individual and community-level risk. In regards to increasing an individual's risk of SED/EH, two factors, gender (being male) and low maternal education (mother not completing high school at the time of the child's birth), were found to have particularly strong effects. When examining effects of these risk factors upon overall rates of SED/EH in the community, maternal education and marital status (being unmarried at the time of the child's birth) were associated with a large proportion of the cases. Health/biological markers were moderately associated with SED/EH on the individual level, but were related to a relatively small percentage of cases in the population. In addition, effects varied based upon ethnic/cultural heritage. Researchers are encouraged to consider using an epidemiological perspective and its potential utility in the field of community psychology and public policy is discussed.

Early childhood anemia and mild or moderate mental retardation.

BACKGROUND: Previous studies questioned the link between early childhood anemia and detrimental child development. OBJECTIVE: A population-based study was conducted to examine the association between early childhood anemia and mild or moderate metal retardation at 10 y of age. DESIGN: The present study linked early childhood nutrition data collected by the Special Supplemental Program for Women, Infants, and Children (WIC) and school records. Hemoglobin values were used to determine the relation between anemia in early life and children's placement in special education classes for mild or moderate mental retardation. Subjects were all participants in the WIC program. A computer program was used to link data from birth, WIC, and school records. RESULTS: Logistic regression showed an increased likelihood of mild or moderate mental retardation associated with anemia, independent of birth weight, maternal education, sex, race-ethnicity, the mother's age, or the child's age at entry into the WIC program. CONCLUSION: These findings support the proposition that efforts to prevent mild and moderate mental retardation should include providing children with adequate nutrition during early childhood.

Influence of birth weight on educational outcomes at age 9: the Miami site of the Infant Health and Development Program.

The Miami site of the Infant Health and Development Program, an early intervention for infants born low birth weight (LBW) and preterm, was investigated. Analyses unique to this sample were required because it was the only site that selected a normal birth weight (NBW) comparison group and had the lowest sociodemographic characteristics. Epidemiological methods determined the effects of LBW and early intervention on school outcomes. Children born LBW who did not receive intervention had an increased risk of scoring below the 10th percentile on achievement tests and were placed in special education three times more often than their peers born NBW. The school outcomes of children born LBW who received intervention were consistently better than those who did not, but were worse than children born NBW; however, differences did not reach statistical significance. Children born LBW who did not receive intervention are at significant risk for poor school outcomes compared with their peers born NBW.

The effects of biological and social risk factors on special education placement: birth weight and maternal education as an example.

The effects of birth weight (BW) and maternal education (ME) on special education placement at age 10 were studied. Epidemiologic methods quantified risk to the individual and to the population using an electronically linked, county-wide database of birth and school records. A dose-response relationship was found between BW and ME. High ME may serve as a buffer for children with a biological risk for developmental delays. A clinically important finding was that children born with very low BW to mothers with low ME were at a high level of individual risk for receiving special education services. However, such children accounted for a small number of the overall cases. The largest percentage of children receiving special education services had the single risk factor of low ME. From a public policy standpoint, children born to mothers with low levels of education are an important group to target for early intervention.

Pefloxacin therapy for experimental endocarditis caused by methicillin-susceptible or methicillin-resistant strains of Staphylococcus aureus.

The therapeutic efficacy of pefloxacin in experimental endocarditis caused by methicillin-susceptible or methicillin-resistant Staphylococcus aureus was evaluated. In rabbits infected with a methicillin-susceptible strain, 4 days of pefloxacin therapy significantly reduced both the number of bacteria per gram of vegetation and the mortality rate compared with untreated controls, and pefloxacin was equivalent to cephalothin. Pefloxacin was also as effective as vancomycin in reducing vegetation titers and mortality rate in animals with endocarditis caused by a methicillin-resistant strain. These results suggest that pefloxacin may be an effective agent in the therapy of serious infections caused by either methicillin-susceptible or -resistant strains of S. aureus.

Activities of pefloxacin and ciprofloxacin in experimentally induced Pseudomonas pneumonia in neutropenic guinea pigs.

Pefloxacin and ciprofloxacin are two new quinoline carboxylic acid derivatives that have activity in vitro against a wide range of gram-negative bacteria, including Pseudomonas aeruginosa. Using a well-standardized model of Pseudomonas pneumonia in neutropenic guinea pigs, we tested the efficacy in vivo of these new agents. Both were highly effective in increasing survival and decreasing bacterial counts in the lungs of surviving animals. Pefloxacin and ciprofloxacin were significantly better (P less than 0.05) than aminoglycosides or beta-lactams tested in prior studies with this model, and they were as effective as combination therapy with aminoglycosides and beta-lactams. Resistance to either ciprofloxacin or pefloxacin did not emerge during the study period. Further studies with these drugs in the therapy of Pseudomonas sp. infections are warranted.

New cephalosporins cefotaxime, cefpimizole, BMY 28142, and HR 810 in experimental pneumococcal meningitis in rabbits.

Four new cephalosporins, cefotaxime, cefpimizole (U 63196E), BMY 28142, and HR 810 were evaluated in experimental pneumococcal meningitis. Cefotaxime penetrated only moderately into the cerebrospinal fluid of rabbits with meningitis, whereas cefpimizole, BMY 28142, and HR 810 all exhibited unusually good penetration. The bactericidal activity in infected cerebrospinal fluid was comparable for the four drugs.

Learning theory, intelligence, and mental development.

The current state of experimental research on mental retardation was considered from a historical perspective. The early position that defined intelligence as the ability to learn was presented. Subsequent refinements were traced as intelligence was related first to stages and, subsequently, to subprocesses of learning. Research on learning in retarded persons, which mainly dates from the late 1950s, took little account of this history. The methodological errors that flawed much modern mental retardation research were made explicit. Attempts to isolate the roles of MA and of intelligence were reviewed. It was shown that with growing understanding sophisticated designs emerged. Kappauf's three-dimensional model relating performance to IQ and CA was discussed and some models of retardation presented. Research on the development of intelligence was related to these models and to the design of intervention strategies.