Cure of Helicobacter pylori infection and resolution of gastritis by adoptive transfer of splenocytes in mice

Vaccination suppresses Helicobacter pylori colonization but does not cure infection. Furthermore, postvaccination gastritis, likely induced by enhanced host response to residual colonization, may exacerbate disease. The goal of this study was to determine if adoptive transfer of C57BL/6 splenocytes to C57BL/6scid/scid (severe combined immunodeficient [SCID]) mice cures infection without exacerbating gastritis. H. pylori-infected and uninfected C57BL/6 mice and SCID recipients of normal splenocytes were killed at intervals between 5 and 51 weeks after infection. Colonization and gastritis were quantified, humoral immune responses were determined by enzyme-linked immunosorbent assay, and cellular immune responses were determined by delayed-type hypersensitivity response and by a proliferative response of cultured splenocytes to H. pylori sonicate. In infected C57BL/6 mice, gastritis developed gradually and bacterial colonization diminished but persisted throughout the experiment. In contrast, gastritis in infected recipient SCID mice developed rapidly and bacterial colonization decreased precipitously. Gastritis in those mice peaked 9 weeks after adoptive transfer, however, and began to resolve. By 45 weeks after transfer, gastritis had returned to background levels and bacteria were no longer detectable. Resolution of gastritis and elimination of infection were associated with a cellular but not humoral immune response to H. pylori antigens. These results demonstrate that although the host response fails to clear bacterial colonization in normal mice, enhanced cellular immune responses in recipient SCID mice are capable of clearing H. pylori infection and allowing resolution of gastritis. Thus, immune mechanisms of cure exist, and effective and safe vaccination protocols may be feasible.     

Human antibody response to the B oligomer of pertussis toxin.

To determine whether antibodies to the B oligomer of pertussis toxin (PT) were present in patients diagnosed with pertussis or vaccinees who had received diphtheria-tetanus-whole-cell pertussis vaccine, we analyzed serum samples from 5 patients and 10 vaccinees by both enzyme-linked immunosorbent assay (ELISA) and Western immunoblotting techniques. Antibodies to the B oligomer were detected by ELISA in all samples containing antibodies to holotoxin. Western immunoblotting procedures were less efficient than ELISA techniques for detecting antibodies to the B oligomer. Antibodies which inhibit the ability of the B oligomer to agglutinate erythrocytes were detected in purified human immunoglobulin preparations. In addition, serum samples containing antibodies to PT inhibited the binding of purified B oligomer and holotoxin to a 165-kDa glycoprotein which has been considered a potential PT receptor in Chinese hamster ovary (CHO) cells. These results suggest that antibodies to the B oligomer contribute to the human serologic response to PT, but their detection and characterization require appropriate methods.     

Trends Influencing Future Delivery of Mental Health Services in Large Healthcare Systems

The delivery of mental health services, particularly psychotherapy and other psychosocial care, is being increasingly limited by financial constraints. We briefly review three trends that will play an increasingly important role in the delivery of mental health services in large organizations such as health maintenance organizations. These are (a) an increasing role for self-help and bibliotherapy interventions, both in traditional and electronic formats; (b) mental health services being offered in settings other than mental health specialty clinics; and (c) an increased emphasis on mechanisms for improving the quality and type of services offered, including quality improvement methods and pay-for-performance.     

Activation of the skeletal α-actin promoter during muscle regeneration

Little is known conerning promoter regulation of genes in regenerating skeletal muscles. In young rats, recovery of muscle mass and protein content is complete within 21 days. During the initial 5–10 days of regeneration, mRNA abundance for IGF-I, myogenin and MyoD have been shown to be dramatically increased. The skeletal -actin promoter contains E box and serum response element (SRE) regulatory regions which are directly or indirectly activated by myogenin (or MyoD) and IGF-I proteins, respectively. We hypothesized that the skeletal -actin promoter activity would increase during muscle regeneration, and that this induction would occur before muscle protein content returned to normal. Total protein content and the percentage content of skeletal -actin protein was diminished at 4 and 8 days and re-accumulation had largely occurred by 16 days post-bupivacaine injection. Skeletal - actin mRNA per whole muscle was decreased at day 8, and thereafter returned to control values. During regeneration at day 8, luciferase activity (a reporter of promoter activity) directed by –424 skeletal -actin and –99 skeletal -actin promoter constructs was increased by 700% and 250% respectively; however, at day 16, skeletal -actin promoter activities were similar to control values. Thus, initial activation of the skeletal - actin promoter is associated with regeneration of skeletal muscle, despite not being sustained during the later stages of regrowth. The proximal SRE of the skeletal -actin promoter was not sufficient to confer a regeneration-induced promoter activation, despite increased serum response factor protein binding to this regulatory element in electrophoretic mobility shift assays. Skeletal -actin promoter induction during regeneration is due to a combination of regulatory elements, at least including the SRE and E box. © Kluwer Academic Publishers.     

Identification of a gene from Xp21 with similarity to the tctex-1 gene of the murine t complex

Long range physical mapping within the p21 region of the X chromosomeIdentified a CpG rich Island approximately 180 kb centromericto the chronic granulomatous disease (CGD) locus. The segmentsadjacent to the CpG Island hybridized to discrete bands In DNAsof several species and when used to screen retinal cDNA librariesled to the Identification of cDNAs that detected a mRNA of 2.1kb in many tissues. Molecular characterization of correspondinggenomic clones of this novel human gene confirmed the originof the cDNA clones and Indicated a genomic structure with fiveexons spanning a total of 9 kb. The complete cDNA sequence revealedthat this gene contained a putative open reading frame of 116amino acids with a 3' untranslated region of 1.74 kb. The aminoacid sequence shows a high degree of similarity to the predictedproduct of the tctex-1 gene of the mouse t complex. As linkagestudies and patients with deletions have Implicated the Xp21region as containing the retInltls plgmentosa defect (RP3),the gene was assessed as a candidate disease gene In RP3 families.A single base pair polymorphism was Identified within the codingregion but no disease associated changes were found by singlestrand conformational polymorphism and sequencing analysis ofamplified exons of 20 RP patients. Analysis of a dinucleotiderepeat polymorphism within this gene In families affected withRP3 suggested refinement of the RP3 region.     

Helicobacter pylori gastric infection in gnotobiotic beagle dogs.

Establishment of infection with Helicobacter pylori and gastritis in nonhuman species is currently only successful in gnotobiotic piglets. This study was designed to determine whether H. pylori will colonize the gastrointestinal tract of gnotobiotic dogs. Gnotobiotic beagle pups were derived by standard methods. Group A (five dogs) was orally challenged with 3 x 10(8) H. pylori at 7 days of age. Group B (two dogs) received only peptone water but was contact-exposed beginning on day 23 postinfection (p.i.). Necropsy was performed on dogs on day 30 p.i. H. pylori colonized the stomach of all dogs (groups A and B). Urease map analysis correlated with the microbiologic findings and indicated that the density of colonization was less than that observed in human tissue. Organisms were also recovered from the pharynx, esophagus, duodenum, and rectum of 1, 2, 2, and 1 dog, respectively. All group A and one group B dog developed serum immunoglobulin G specific for H. pylori by day 30 p.i. Gross lesions were restricted to the stomach and consisted of small (less than 1 mm) lymphoid follicles. Microscopically, there were focal to diffuse lymphoplasmacytic infiltrates with follicle formation and mild to moderate infiltration of neutrophils and eosinophils in the gastric lamina propria. With the Warthin-Starry silver stain, organisms were seen on the surface of the gastric epithelial cells, beneath the mucus layer. We conclude that H. pylori colonizes the stomachs of gnotobiotic dogs for at least 1 month and the lesions resemble those seen in humans. H. pylori is transmissible by contact from infected to noninfected dogs.     

Serotonergic neural precursor cell grafts attenuate bilateral hyperexcitability of dorsal horn neurons after spinal hemisection in rat

Hemisection of the rat spinal cord at thoracic level 13 provides a model of spinal cord injury that is characterized by chronic pain attributable to hyperexcitability of dorsal horn neurons. Presuming that this hyperexcitability can be explained in part by interruption of descending inhibitory modulation by serotonin, we hypothesized that intrathecal transplantation of RN46A-B14 serotonergic precursor cells, which secrete serotonin and brain-derived neurotrophic factor, would reduce this hyperexcitability by normalizing the responses of low-threshold mechanoreceptive, nociceptive-specific, and multireceptive dorsal horn neurons. Three groups (n=45 total) of 30-day-old male Sprague-Dawley rats underwent thoracic level 13 spinal hemisection, after which four weeks were allowed for development of allodynia and hyperalgesia. The three groups of animals received transplants of no cells, 10(6) RN46A-V1 (vector-only) or 10(6) RN46A-B14 cells at lumbar segments 2-3. Electrophysiological experiments were done two weeks later. Low-threshold mechanoreceptive, nociceptive-specific, and multireceptive cells (n=394 total) were isolated at depths of 1-300 and 301-1000 micro in the lumbar enlargement. Responses to innocuous and noxious peripheral stimuli were characterized, and analyses of population responses were performed. Compared with normal animals, dorsal horn neurons of all types in hemisected animals showed increased responsiveness to peripheral stimuli. This was true for neurons on both sides of the spinal cord. After hemisection, the proportion of neurons classified as multireceptive cells increased, and interspike intervals of spontaneous discharges became less uniform after hemisection. Transplantation of RN46A-B14 cells restored evoked responses to near-control levels, normalized background activity, and returned the proportion of multireceptive cells to the control level. Restoration of normal activity was reversed with methysergide.These electrophysiological results corroborate anatomical and behavioral studies showing the effectiveness of serotonergic neural precursors in correcting phenomena associated with chronic central pain following spinal cord injury, and provide mechanistic insights regarding mode of action.     

Factors affecting the determination of threshold doses for allergenic foods: how much is too much?

BACKGROUND: Ingestion of small amounts of an offending food can elicit adverse reactions in individuals with IgE-mediated food allergies. The threshold dose for provocation of such reactions is often considered to be zero. However, because of various practical limitations in food production and processing, foods may occasionally contain trace residues of the offending food. Are these very low, residual quantities hazardous to allergic consumers? How much of the offending food is too much? Very little quantitative information exists to allow any risk assessments to be conducted by the food industry. OBJECTIVE: We sought to determine whether the quality and quantity of existing clinical data on threshold doses for commonly allergenic foods were sufficient to allow consensus to be reached on establishment of threshold doses for specific foods. METHODS: In September 1999, 12 clinical allergists and other interested parties were invited to participate in a roundtable conference to share existing data on threshold doses and to discuss clinical approaches that would allow the acquisition of that information. RESULTS: Considerable data were identified in clinical files relating to the threshold doses for peanut, cows' milk, and egg; limited data were available for other foods, such as fish and mustard. CONCLUSIONS: Because these data were often obtained by means of different protocols, the estimation of a threshold dose was very difficult. Development of a standardized protocol for clinical experiments to allow determination of the threshold dose is needed.