Effects of Orally Administered Epidermal Growth Factor on Enteropathogenic Escherichia coli Infection in Rabbits

The increased intestinal absorption induced by epidermal growth factor (EGF) is associated with diffuse lengthening of brush border microvilli. The aim of this study was to examine the in vivo effects of oral administration of EGF during infection with enteropathogenic Escherichia coli. New Zealand White rabbits (4 weeks old) received orogastric EGF daily starting 3 days prior to infection with enteropathogenic E. coli RDEC-1 and were compared with sham-treated infected animals and uninfected controls. Weight gain, food intake, fecal E. coli, and stool consistency were assessed daily. On day 10, segments of jejunum, ileum, proximal, and distal colon were assessed for gram-negative bacterial colonization, disaccharidase activities, and epithelial ultrastructure. Effects of EGF on E. coli RDEC-1 proliferation were studied in vitro. E. coli RDEC-1 caused diarrhea and reduced weight gain. Seven days postinfection, the small and large intestines were colonized with numerous bacteria, brush border microvilli were disrupted, and maltase and sucrase activities were significantly reduced in the jejunum. Daily treatment with EGF prevented the occurrence of diarrhea and reduction of weight gain. These effects were associated with significant inhibition of E. coli colonization in the small and large intestine, improved jejunal maltase and sucrase activities and reduced microvillous injury. EGF did not affect the proliferation of E. coli in vitro. The findings suggest that EGF protects the gastrointestinal tract against colonization by enteropathogenic E. coli.     

Detection by PCR and isolation assays of the anaerobic intestinal spirochete Brachyspira aalborgi from the feces of captive nonhuman primates

The purpose of this study was to investigate the presence of the anaerobic intestinal spirochetes Brachyspira aalborgi and Brachyspira pilosicoli in the feces of captive nonhuman primates (n = 35) from 19 species housed at the Zoological Gardens, Perth, Western Australia. Both spirochete species are known to infect human beings. DNA was extracted from freshly collected feces with a commercially available QIAamp DNA stool minikit and subjected to PCR protocols amplifying portions of the 16S rRNA genes of the two spirochete species. The feces were also subjected to selective culture for the spirochetes. Subsequently, feces from 62 other captive animals or birds representing 39 species at the zoo were examined by PCR to determine whether they were reservoirs of infection. Six fecal samples from individuals from four primate species (two vervet monkeys, two Tonkean macaques, one Japanese macaque, and one hamadryas baboon) tested positive in the B. aalborgi PCR. B. aalborgi was not detected by PCR in any of the other animal or bird species tested, and B. pilosicoli was not detected in the primates or any of the other animals or birds. B. aalborgi was isolated from both PCR-positive vervet monkeys. This is the first time that B. aalborgi has been isolated from nonhuman primates and the first time that it has been isolated from the feces of any species.     

Repeat sequences in block 2 of Plasmodium falciparum merozoite surface protein 1 are targets of antibodies associated with protection from malaria

Human antibodies to the block 2 region of Plasmodium falciparum merozoite surface protein 1 (MSP1) are associated with a reduced prospective risk of clinical malaria. Block 2 is highly polymorphic, but all known alleles can be grouped into three major types. Two of these types (the K1-like and MAD20-like types) contain type-specific sequences (found in all alleles of a particular type) that flank polymorphic tripeptide repeats. These repeats contain both type-specific and subtype-specific sequences. To evaluate the antibody recognition of these parts of block 2, a new panel of six recombinant proteins was used (fused type-specific flanking sequences and two representative repeat sequences for each of the K1-like and MAD20-like types separately). Extensive testing of these antigens and full-length block 2 antigens showed that human serum immunoglobulin G antibodies induced by infection can recognize (i) type-specific epitopes in the repeats, (ii) subtype-specific epitopes in the repeats, or (iii) type-specific epitopes in flanking sequences. A large prospective study in The Gambia showed that antibodies to the repeats are strongly associated with protection from clinical malaria. The results are important for design of a vaccine to induce protective antibodies, and they address hypotheses about repeat sequences in malaria antigens.     

Micromechanical properties of demineralized dentin collagen with and without adhesive infiltration

In a previous study, we reported the upper limit of Young's modulus of the unprotected protein at the dentin/adhesive interface to be 2 GPa. In this study, to obtain a more exact value of the moduli of the components at the d/a interface, we used demineralized dentin collagen with and without adhesive infiltration. The prepared samples were analyzed using micro-Raman spectroscopy (micro RS) and scanning acoustic microscopy (SAM). Using an Olympus UH3 SAM (Olympus Co., Tokyo), measurements were recorded with a 400 MHz burst mode lens (120 degrees aperture angle; nominal lateral resolution, 2.5 microm). A series of calibration curves were prepared using the relationship between the ultrasonically measured elastic moduli of a set of known materials and their SAM response. Finally, both the bulk and bar wave elastic moduli were computed for a set of 13 materials, including polymers, ceramics, and metals. These provided the rationale for using extensional wave measurements of the elastic moduli as the basis for extrapolation of the 400 MHz SAM data to obtain Young's moduli for the samples: E = 1.76 +/- 0.00 GPa for the collagen alone; E = 1.84 +/- 0.65 GPa for the collagen infiltrated with adhesive; E = 3.4 +/- 1.00 GPa for the adhesive infiltrate.     

Neutrophil activity in abscess-bearing mice: comparative studies with neutrophils isolated from peripheral blood, elicited peritoneal exudates, and abscesses.

Intraabdominal abscesses were induced in mice by intraperitoneal inoculation of Bacteroides fragilis and Escherichia coli plus bran as the abscess-potentiating agent. Six- or seven-day-old abscesses were mechanically disaggregated in buffer, and the cells obtained were fractionated on discontinuous Percoll density gradients. Neutrophil populations of different density, each approximately 90% pure, were isolated. When the abscess-derived neutrophils were subsequently incubated with normal serum in vitro under aerobic conditions, the viability of the gram-negative bacteria that had been phagocytosed within the abscess did not change significantly. This anergy to intracellular bacteria (on subsequent incubation in vitro under optimal conditions for phagocytic killing) was also found for neutrophils that had been obtained from abscesses induced by a mixture that included Proteus mirabilis plus B. fragilis and from those induced by E. coli plus P. mirabilis. While unable to significantly kill intracellular organisms that had been phagocytosed in vivo, the abscess-derived neutrophils could engulf and kill organisms to which they were exposed in vitro. Neutrophils from abscesses induced by P. mirabilis only plus bran killed that organism introduced in vitro significantly more effectively than the organisms that had been engulfed in vivo. In contrast, neutrophils from abscesses induced by the gram-positive organism Staphylococcus aureus plus bran were able to kill their intracellular organisms on subsequent incubation in vitro as effectively as they could kill added S. aureus. Neutrophils isolated from the peripheral blood and from induced peritoneal exudates of abscess-bearing mice were able to phagocytose and kill organisms in vitro with greater efficiency than abscess-derived neutrophils. The mechanism whereby neutrophils from abscesses induced by the gram-positive organism S. aureus can kill the organisms phagocytosed in vivo on subsequent in vitro incubation, in contrast to the relative anergy to their intracellular organisms displayed by neutrophils derived from abscesses induced by combinations of gram-negative bacteria, is not known.     

Immunologic mechanisms in hypersensitivity pneumonitis: I. Evidence for cell-mediated immunity and complement fixation in pigeon breeders' disease

Immunologic studies were performed on 5 patients with pigeon breeders' disease. Intradermal injection of pigeon serum produced an immediate wheal-and-flare reaction within 15 minutes and a secondary Arthus-type reaction within 4 to 8 hours. Immunofluorescent studies of the secondary reaction site showed IgG, C3, and C4 in 2 patients. Patients' sera produced multiple precipitin bands with pigeon serum when reacted by double diffusion in gel. IgG antibody isolated from each of the patients' serum formed precipitating immune complexes that fixed large amounts of complement (C4) when added to fresh human serum. Peripheral blood lymphocytes from 4 of the 5 patients produced macrophage migration inhibitory factor (MIF) when challenged with dilute pigeon serum. These studies are the first to show complement fixing antibodies and macrophage MIF production by lymphocytes from patients with hypersensitivity lung disease and suggest that both humoral and cellular immunity may be important in the pathogenesis of these disorders.     

Development of neural processes mediating rhyme judgments: Phonological and orthographic interactions

Development of neural processes underlying integration of phonological and orthographic information were assessed by measuring event-related brain potentials (ERPs), judgment accuracies and reaction times (RTs) in 20 children (9-10 years) and 20 adults performing visual rhyme judgments. Half the trials were phonologically and orthographically congruent across the prime-target pairs (e.g., thrown-own, cake-own), and half were incongruent (e.g., gown-own, cone-own). For both children and adults, behavioral performance was most affected when different phonological representations had to be encoded from similar orthographic representations (e.g., gown-own), and the amplitudes of the N350 reflected effects of both rhyme and phonological/orthographic congruency. Latencies of the N350 were shorter over the left hemisphere only in adults, and phonological/orthographic incongruence produced greater delays in children's processing. Therefore, it appears that neural systems mediating rhyming judgments develop early; however, adults exhibit increased efficiency for left-hemisphere processing and are less affected by interference from incongruent phonological and orthographic codes.     

Papillary fibroelastoma: a cardiac tumor rarely reported in children

Papillary fibroelastoma is a seldom reported tumour. It usually occurs in adults and develops on the aortic and mitral valves. It is not different of giant Lambl excrescences and differential diagnostic can be difficult with the myxoma. Its systematic surgical ablation is justified by the important risk of embolic complications. It has rarely been reported in children. We report a case peculiar by fortuitous diagnostic, tricuspid site, large size and occurrence in a 3-year old child.     

Audit and academic departments of general practice: a survey in the United Kingdom and Eire.

A questionnaire and telephone survey was carried out in April 1991 of all 31 academic departments of general practice in the United Kingdom and Eire; 30 departments responded. The aim of the study was to assess the departments' level of involvement in teaching about audit in the undergraduate curriculum, their role in the development of audit in primary care including involvement with medical audit advisory groups, whether they undertook teaching about audit to other health professionals and whether they were involved in audit related research. Eleven of 27 responding undergraduate departments provided formal teaching about audit and five intended to introduce it in the near future. Respondents expressed concerns about teaching audit to undergraduates, including lack of time in the curriculum, difficulties making the teaching relevant and interesting, and a lack of expertise and knowledge of the subject among the staff. All 29 departments in the UK were represented on medical audit advisory groups, and audit related research was being carried out in 24 undergraduate departments. The role of academic departments of general practice in the development of audit in primary care is discussed.