Immunodetection of Helicobacter sp. and the associated expression of ABO blood group antigens in the gastric mucosa of captive and free-living New World primates in the Amazon region

The histo-blood group ABH antigens were first described in humans. These antigens are only present on erythrocytes from great apes and humans, while in more primitive animals they are found in tissues and body fluids. The ABH antigens are mainly distributed in tissues exposed to the external environment and potentially serve as ligands for pathogens or inhibitors of tissue connections. The objective of this paper was two-fold: (i) to determine the presence of Helicobacter sp. in the gastric mucosa of 16 captive and 24 free-living New World monkeys and (ii) to evaluate the presence of histopathological alterations related to bacterial infection and the associated expression of ABH antigens in the tissue. Stomach tissues from 13 species of monkey were assessed using haematoxylin-eosin and modified Gram staining (Hucker) methods. An immunohistochemical analysis of the tissue revealed the presence of infectious bacteria that were characteristic of the genus Helicobacter sp. The results demonstrate that various species of monkey might be naturally infected with the Helicobacter sp. and that there is an increased susceptibility to infection. This study serves as a comparative analysis of infection between human and non-human primates and indicates the presence of a new species of Helicobacter.

Reduction of Helicobacter infection in IL-10-/- mice is dependent on CD4+ T cells but not on mast cells.

BACKGROUND: In contrast to wild type, interleukin-10-deficient (IL-10(-/-)) mice are able to clear Helicobacter infection. In this study, we investigated the immune response of IL-10(-/-) mice leading to the reduction of Helicobacter infection. MATERIALS AND METHODS: We characterized the immune responses of Helicobacter felis-infected IL-10(-/-) mice by studying the systemic antibody and cellular responses toward Helicobacter. We investigated the role of CD4(+) T cells in the Helicobacter clearance by injecting H. felis-infected IL-10(-/-) mice with anti-CD4 depleting antibodies. To examine the role of mast cells in Helicobacter clearance, we constructed and infected mast cells and IL-10 double-deficient mice. RESULTS: Reduction of Helicobacter infection in IL-10(-/-) mice is associated with strong humoral (fivefold higher serum antiurease antibody titers were measured in IL-10(-/-) in comparison to wild-type mice, p < .008) and cellular (urease-stimulated splenic CD4(+) T cells isolated from infected IL-10(-/-) mice produce 150-fold more interferon-gamma in comparison to wild-type counterparts, p < .008) immune responses directed toward Helicobacter. Depletion of CD4(+) cells from Helicobacter-infected IL-10(-/-) mice lead to the loss of bacterial clearance (rapid urease tests are threefold higher in CD4(+) depleted IL-10(-/-) in comparison to nondepleted IL-10(-/-) mice, p < .02). Mast cell IL-10(-/-) double-deficient mice clear H. felis infection, indicating that mast cells are unnecessary for the bacterial eradication in IL-10(-/-) mice. CONCLUSION: Taken together, these results suggest that CD4(+) cells are required for Helicobacter clearance in IL-10(-/-) mice. This reduction of Helicobacter infection is, however, not dependent on the mast cell population.

PAR2 Promotes Vaccine-Induced Protection Against Helicobacter Infection in Mice.

BACKGROUND & AIMS: Protective immunization limits Helicobacter infection of mice by undetermined mechanisms. Protease-activated receptor 2 (PAR2) signaling is believed to regulate immune and inflammatory responses. We investigated the role of PAR2 in vaccine-induced immunity against Helicobacter infection. METHODS: Immune responses against Helicobacter infection were compared between vaccinated PAR2(-/-) and wild-type (WT) mice. Bacterial persistence, gastric pathology, and inflammatory and cellular responses were assessed using the rapid urease test (RUT), histologic analyses, quantitative polymerase chain reaction, and flow cytometry, respectively. RESULTS: Following vaccination, PAR2(-/-) mice did not have reductions in Helicobacter felis infection (RUT values were 0.01 ± 0.01 for WT mice and 0.11 ± 0.13 for PAR2(-/-) mice; P < .05). The vaccinated PAR2(-/-) mice had reduced inflammation-induced stomach tissue damage (tissue damage scores were 8.83 ± 1.47 for WT mice and 4.86 ± 1.35 for PAR2(-/-) mice; P < .002) and reduced T-helper (Th)17 responses, based on reduced urease-induced interleukin (IL)-17 secretion by stomach mononuclear cells (5182 ± 1265 pg/mL for WT mice and 350 ± 436 pg/mL for PAR2(-/-) mice; P < .03) and reduced recruitment of CD4(+) IL-17(+) T cells into the gastric mucosa of PAR2(-/-) mice following bacterial challenge (3.7% ± 1.5% for WT mice and 2.6% ± 1.1% for PAR2(-/-) mice; P < .05). In vitro, H felis-stimulated dendritic cells (DCs) from WT mice induced greater secretion of IL-17 by ovalbumin-stimulated OT-II transgenic CD4(+) T cells compared with DCs from PAR2(-/-) mice (4298 ± 347 and 3230 ± 779; P < .04), indicating that PAR2(-/-) DCs are impaired in priming of Th17 cells. Adoptive transfer of PAR2(+/+) DCs into vaccinated PAR2(-/-) mice increased vaccine-induced protection (RUT values were 0.11 ± 0.10 and 0.26 ± 0.15 for injected and noninjected mice, respectively; P < .03). CONCLUSIONS: PAR2 activates DCs to mediate vaccine-induced protection against Helicobacter infection in mice.

Pneumocystis-carinii-Pneumonie bei Säuglingen mit vertikaler HIV-Infektion in der Schweiz [Pneumocystis carinii pneumonia in infants with vertically acquired HIV infection in Switzerland]

OBJECTIVE: Review of incidence, clinical picture, therapy, and outcome of Pneumocystis carinii pneumonia (PCP) in infants with vertically-acquired HIV infection in Switzerland. METHODS: Inquiry among members of the Swiss Pediatrics AIDS Group, review of the data base of the Swiss Neonatal HIV Study and retrospective analysis of the charts from infants with PCP. RESULTS: Since 1986 PCP has been diagnosed in 10 out of 107 infants with vertically-acquired HIV infection. PCP occurred in 7 infants at the age of 3-6 months and in 3 at the age of 9-11 months. 4 infants showed symptoms related to HIV infection before developing PCP. Before the development of PCP, infection with HIV had been ascertained in 6 infants. In 2 the diagnosis was still unclear and in the 2 remaining the risk of HIV infection was not known. None of the infants was on primary prophylaxis against PCP. Signs and symptoms of PCP included cough and tachypnea (100%) as well as high fever up to 40 degrees C (90%). Transcutaneous oxygen saturation was 70-95%. Chest X-rays revealed interstitial infiltrates in 6 infants, localized infiltrates in 2 and interstitial as well as localized infiltrates in 2. The CD4+ cell count was, with one exception, < 1500/microliters, i.e. below the normal value for age. Side effects of high dose cotrimoxazole were noted in 6 patients. 5 infants required intubation and mechanical ventilation. 4 infants died due to PCP, including 3 of those who required intubation and mechanical ventilation. CONCLUSIONS: PCP in infants with vertically-acquired HIV infection preferentially occurs at the age of 3 to 6 months and is often lethal, especially in patients requiring intubation. Evaluation for HIV infection should be done as early as possible in order to introduce primary PCP prophylaxis in infants at risk for this opportunistic infection.

Hepatic changes in mice chronically infected with Helicobacter trogontum

We infected NIH germ-free female mice with Helicobacter trogontum, a recently described intestinal bacterium of rats, in order to study the lesions it induced in the liver of this host. Fifteen mice were challenged with a single dose of H. trogontum (test group) and killed 6, 12 and 18 months after inoculation (5 animals/group). Nine animals were challenged with 0.85% saline alone (control group) and killed at the same times. Fragments from the liver, cecum and colon were obtained for microbiologic and histologic examination. Stool samples were also collected. H. trogontum was detected in the cecum, colon and/or stool samples of all test mice. As expected, the bacterium was not isolated from any specimen obtained from the control animals. On the other hand, although we could not cultivate the bacterium from the liver, 13 test animals (86.7%) presented histological changes in this organ. The 6-month group presented infiltration of mononuclear and polymorphonuclear cells in the hepatic parenchyma and the two other groups presented foci of mononuclear cells. The results suggest that H. trogontum can elicit a hepatic inflammatory response in mice since the only difference between control and test animals was the presence of H. trogontum in the latter. This result, together with the growing number of related reports in the literature, reinforces the possible role of Helicobacter infection in the pathogenesis of hepatobiliary diseases.

Alterações comportamentais, psicológicas, de higiene bucal e presença de microrganismos superinfectantes e viruses da família herpesviridae em pacientes mantidas em programa de desintoxicação para dependentes químicos

Pós-graduação em Odontologia - FOA

Immunodetection of Helicobacter sp. and the associated expression of ABO blood group antigens in the gastric mucosa of captive and free-living New World primates in the Amazon region

The histo-blood group ABH antigens were first described in humans. These antigens are only present on erythrocytes from great apes and humans, while in more primitive animals they are found in tissues and body fluids. The ABH antigens are mainly distributed in tissues exposed to the external environment and potentially serve as ligands for pathogens or inhibitors of tissue connections. The objective of this paper was two-fold: (i) to determine the presence of Helicobacter sp. in the gastric mucosa of 16 captive and 24 free-living New World monkeys and (ii) to evaluate the presence of histopathological alterations related to bacterial infection and the associated expression of ABH antigens in the tissue. Stomach tissues from 13 species of monkey were assessed using haematoxylin-eosin and modified Gram staining (Hucker) methods. An immunohistochemical analysis of the tissue revealed the presence of infectious bacteria that were characteristic of the genus Helicobacter sp. The results demonstrate that various species of monkey might be naturally infected with the Helicobacter sp. and that there is an increased susceptibility to infection. This study serves as a comparative analysis of infection between human and non-human primates and indicates the presence of a new species of Helicobacter.

Analyse molekularer Mechanismen der Immundominanz MHC Klasse I-präsentierter Antigene bei Humaner Cytomegalovirus-Infektion

Das Humane Cytomegalovirus (HCMV) ist ein Erreger von großer klinischer Relevanz. Die HCMV-Infektion, die insbesondere bei immunsupprimierten Patienten mit hoher Morbidität und Mortalität assoziiert ist, wird vorwiegend durch CD8+-zytotoxische T-Lymphozyten (CTL) kontrolliert. Das Tegumentprotein pp65 und das immediate early 1-Protein (IE1) waren als die dominanten CTL-Antigene bekannt. Ziel dieser Arbeit war es, die zur Immundominanz des pp65 führenden molekularen Mechanismen aufzuklären und die Grundlagen für die Analyse der IE1-spezifischen Immunantwort zu erarbeiten. Durch Peptidimmunisierung HLA-A2-transgener Mäuse wurden hochaffine pp65-spezifische CTL-Klone generiert. Für die Generierung ähnlicher CTL-Klone gegen IE1 konnte erstmals ein konserviertes HLA-A2-bindendes Peptid identifiziert werden. Mit Hilfe der pp65-spezifischen CTL-Klone konnte gezeigt werden, dass das durch Viruspartikel in die Zelle eingebrachte pp65 die Erkennung infizierter Zellen durch CD8+-CTL vermittelt. Durch den Nachweis der außergewöhnlichen Stabilität von pp65 in der Zelle gelang es, eine hohe metabolische Umsatzrate als eine Ursache von Immundominanz auszuschließen. Dagegen hob die Blockierung des CRM1-vermittelten nukleären Exportweges durch Zugabe von Hemmstoffen oder Zutransfektion kompetitiver Inhibitoren die Erkennung des pp65 nahezu auf. Hiermit wurde erstmalig eine Abhängigkeit der Präsentation eines immundominanten nukleären Proteins vom nukleozytoplasmatischen Transport nachgewiesen. Die Erkenntnisse dieser Arbeit stellen die Grundlage für die detaillierte Analyse der Zusammenhänge zwischen nukleärem Export und Antigenpräsentation dar.

Der Einfluss einer Cytomegalovirus-Infektion auf das Risiko eines Leukämie-Rezidivs nach Knochenmarktransplantation

Eine Erkrankung durch das humane Cytomegalovirus (hCMV) und ein Rezidiv des Ausgangstumors sind zwei gravierende Komplikationen im Rahmen der Therapie von Malignomen des hämatopoetischen Systems durch Knochenmarktransplantation (KMT). Eine mögliche pathogenetische Interaktion zwischen hCMV-Infektion und einem von einer Minimalen Residualen Leukämie (MRL) ausgehenden Rezidiv wurde bislang in klinischen Verlaufsstudien nach KMT noch nicht systematisch untersucht.In der vorliegenden Arbeit wurde der Einfluss von CMV auf ein Lymphom in einem Modellsystem untersucht. Dazu erweiterten wir das etablierte Modell der murinen CMV (mCMV) Infektion nach experimenteller syngener KMT mit dem Mausstamm BALB/c als Spender und Empfänger durch ein B-Zell-Lymphom als weiteren Parameter. Als Modell-Lymphom diente uns eine mit dem Reportergen lacZ transfizierte, ex tumore klonierte, in der Leber hochgradig tumorigene Variante (Klon E12E) des von BALB/c abgeleiteten B-Zell-Lymphoms A20. Die Arbeiten führten zur Erstbeschreibung einer anti-metastatischen Wirkung der mCMV-Infektion (Erlach at al., 2002; J. Virol. 76: 2857-2870).Im neu etablierten Tiermodell konnte erstmals gezeigt werden, dass eine CMV-Infektion die Ansiedelung eines murinen B-Zell-Lymphoms in der Leber deutlich verringert. Damit wurde die Entstehung einer letalen Tumorerkrankung, abhängig von der Ausgangslast an Tumorzellen signifikant verzögert oder sogar ganz verhindert. Die Suche nach Mechanismen, die diesen antitumoralen Effekt von mCMV verursachen, führte zu folgenden Ergebnissen: Im Unterschied zu onkolytischen Viren basiert die antitumorale Wirkung von mCMV nicht auf einer zytozidalen Infektion der Lymphomzellen. Darüber hinaus zeigt mCMV keine zytostatische oder Apoptose-induzierende Wirkung. Außerdem sind die rekonstituierenden Knochenmarkzellen als Effektoren für den anti-Tumoreffekt auszuschließen. Direkte zytotoxische, sowie systemische Effekte von TNF-alpha konnten als antitumorale Mechanismen ausgeschlossen werden. Die intravenöse Applikation von UV-inaktiviertem Virus zeigte ebenfalls eine Inhibition des Lymphomwachstums, so dass der antitumorale Effekt offenbar durch virale Strukturproteine (Virion-Proteine) ausgelöst wird.Auf der Basis dieser Daten vermuten wir eine Inhibition der Extravasation (transendotheliale Migration/Diapedese) der Tumorzellen aufgrund einer gestörten Kommunikation zwischen Tumorzelle und sinusoidalem Endothel der Leber. Das virale Hüll-Glykoprotein B kann aufgrund seiner signalinduzierenden Wirkung als ein guter Kandidat angesehen werden.

Metodi biochimici e biomolecolari applicati alla medicina clinica: rendimento della real-time TaqMan PCR per la valutazione della resistenza alla claritromicina in H.pylori e tests fecali nella diagnorstica del carcinoma colo-rettale: M2PK, calprotectina e FOBT

1) Background: The most common methods to evaluate clarithromycin resistance is the E-Test, but is time consuming. Resistance of Hp to clarithromycin is due to point mutations in the 23S rRNA. Eight different point mutations have been related to CH resistance, but the large majority of the clarithromycin resistance depends on three point mutations (A2142C, A2142G and A2143G). A novel PCR-based clarithromycin resistance assays, even on paraffin-embedded biopsy specimens, have been proposed. Aims: to assess clarithromycin resistance detecting these point mutation (E-Test as a reference method);secondly, to investigate relation with MIC values. Methods: Paraffin-embedded biopsies of patients Hp-positive were retrieved. The A2142C, A2142G and A2143G point mutations were detected by molecular analysis after DNA extraction by using a TaqMan real-time PCR. Results: The study enrolled 86 patients: 46 resistant and 40 sensible to CH. The Hp status was evaluated at endoscopy, by rapid urease test (RUT), histology and hp culture. According to real-time PCR, 37 specimens were susceptible to clarithromycin (wild type dna) whilst the remaining 49 specimens (57%) were resistant. A2143G is the most frequent mutation. A2142C always express a resistant phenotype and A2142G leads to a resitant phenotype only if homozigous. 2) Background: Colonoscopy work-load for endoscopy services is increasing due to colorectal cancer prevention. We tested a combination of faecal tests to improve accuracy and prioritize the access to colonoscopy. Methods: we tested a combination of fecal tests (FOBT, M2-PK and calprotectin) in a group of 280 patients requiring colonoscopy. Results: 47 patients had CRC and 85 had advanced adenoma/s at colonoscopy/histology. In case of single test, for CRC detection FOBT was the test with the highest specificity and PPV, M2-PK had the highest sensitivity and higher NPV. Combination was more interesting in term of PPV. And the best combination of tests was i-FOBT + M2-PK.

Ausbreitung einer Infektion durch ein System Brownscher Bewegungen

In dieser Arbeit werden wir ein Modell untersuchen, welches die Ausbreitung einer Infektion beschreibt. Bei diesem Modell werden zunächst Partikel gemäß eines Poissonschen Punktprozesses auf der reellen Achse verteilt. Bis zu einem gewissen Punkt auf der reellen Achse sind alle Partikel von einer Infektion befallen. Während sich nicht infizierte Partikel nicht bewegen, folgen die infizierten Partikel den Pfaden von voneinander unabhängigen Brownschen Bewegungen und verbreitet die Infektion dabei an den Orten, welche sie betreten. Wenn sie dabei auf ein nicht infiziertes Partikel treffen, ist dieses von diesem Moment an auch infiziert und beginnt ebenfalls, dem Pfad einer Brownschen Bewegung zu folgen und die Infektion auszubreiten. Auf diese Art verschiebt sich nun der am weitesten rechts liegende Ort R_t, an dem die Infektion bereits verbreitet wurde. Wir werden mit Hilfe des subadditiven Ergodensatzes zeigen, dass sich dieser Ort mit linearer Geschwindigkeit fortbewegt. Ferner werden wir eine obere und eine untere Schranke für die Ausbreitungsgeschwindkeit angeben. Danach werden wir zeigen, dass der Prozess Regenerationszeiten hat, nämlich solche zufällige Zeiten, zu denen er eine Art Neustart unter speziellen Startbedingungen durchführt. Wir werden diese für eine weitere Charakterisierung der Ausbreitungsgeschwingkeit nutzen. Ferner erhalten wir durch die Regenerationszeiten auch einen Zentralen Grenzwertsatz für R_t und können zeigen, dass die Verteilung der infizierten Partikel aus Sicht des am weitesten rechts liegenden infizierten Ortes gegen eine invariante Verteilung konvergiert.