How the interval between prime and boost injection affects the immune response in a computational model of the immune system.

The immune system is able to respond more vigorously to the second contact with a given antigen than to the first contact. Vaccination protocols generally include at least two doses, in order to obtain high antibody titers. We want to analyze the relation between the time elapsed from the first dose (priming) and the second dose (boost) on the antibody titers. In this paper, we couple in vivo experiments with computer simulations to assess the effect of delaying the second injection. We observe that an interval of several weeks between the prime and the boost is necessary to obtain optimal antibody responses.

Endocytoscopy can identify dysplasia in aberrant crypt foci of the colorectum: a prospective in vivo study.

BACKGROUND AND STUDY AIM: A catheter-type endocytoscope has recently been developed that is able to provide in vivo cellular images of gastrointestinal mucosa. Aberrant crypt foci (ACF) represent the earliest precursor of colorectal cancer featuring the dysplasia-carcinoma sequence. The aim of the current study was to assess the potential of the endocytoscopy system (ECS) in the "in vivo" detection of dysplasia in colorectal ACF. PATIENTS AND METHODS: Consecutive patients with colorectal ACF were studied with endocytoscopy. Blinded endoscopic and histological assessments were obtained. Lesions were excised en bloc for histology. RESULTS: A total of 48 colorectal lesions were examined in 41 patients. The mean duration of the ECS procedure was 44 +/- 12 minutes (range 31 - 62 minutes). The quality of ECS images was rated as good in 39/48, medium in six, and poor in three (6.2 %). It was possible to observe lesions at the cellular level and evaluate both cellular and structural atypia in vivo. In normal mucosa, crypts had preserved individuality and round-shaped contours. Nuclei were located at the basal third of the crypt in a single line, and the lumen was circular. In dysplastic ACF, crypt contours were polygonal, cell nuclei were elongated with pseudostratification toward the luminal half of the crypt and irregularly arranged, and the lumen was linear. In all, 23 endocytoscopic images were labeled as dysplastic and 25 as nondysplastic. Histology confirmed low-grade dysplasia in 21/23 cases (91.4 % sensitivity). Absence of dysplasia was confirmed in the remaining 25 cases (100 % specificity). Interobserver agreement between trained endoscopist and pathologist was good (wK 0.68; 95 % CI 0.59 - 0.78). CONCLUSIONS: Endocytoscopy provides real-time histological images in vivo, with clear visualization of cellular details and features of dysplasia in colorectal ACF.

Successful endoscopic treatment of Bouveret's syndrome by mechanical lithotripsy.

Gastric outlet obstruction secondary to the impaction of large biliary stones into the duodenum (Bouveret's syndrome) is a well-known complication of biliary lithiasis, most often requiring surgical intervention. We report a case of successful endoscopic removal of a large stone impacted in the duodenal bulb by means of mechanical lithotripsy.

Management of gastro-oesophageal reflux disease: role of proton pump inhibitor test and upper gastro-intestinal endoscopy.

Authors report the available scientific evidence on the role of proton pump inhibitors and upper gastro-intestinal endoscopy in the management of patients with gastro-oesophageal reflux disease. Relative indications, advantages and pitfalls of various diagnostic and therapeutic strategies for cost-effective management of this condition are discussed. The most recent evidence-based guidelines are outlined.

[Vaccine coverage study and intervention with health community agents in a marginal gypsy community of Alicante]. / Estudio de la cobertura vacunal e intervención con agentes de salud comunitarios en población infantil marginal gitana de Alicante.

UNLABELLED: OBJEDTIVESñ To measure the vaccination coverage in a pediatric population living in Parque Ansaldo, Montoto, Casa Larga, Cabrera Vicario, San Antón and Travesía del Canal and evolution after an intervention health program performed by Gypsy educators specially trained for such intervention. DESIGN: Descriptive study, pretest-postest without control group. SETTING: Community. Primary health care. Participants. Four hundred and sixty three marginals Gypsies children younger than 15 years old. MEASUREMENTS AND MAIN RESULTS: The project includes an educational program and health care actions by means of home visits. Duration of the project was from 1-10-96 until 1-10-97 and from 1-10-98 until 1-10-99. Before intervention the vaccine coverage was for polio, diphtheria and tetanus 41%, pertussis 24% and measles, mumps and rubella 36%. After intervention the overall coverage increased 17%. The vaccine coverage was for polio, diphtheria and tetanus 53%, pertussis 45% y measles, mumps and rubella 54%. CONCLUSIONS: This study shows up the low vaccine coverage founded and the increase of overall coverage after the intervention in 17%. We also conclude of the intervention the necesity of collaboration between Gypsies associations, health primary care centers and public health centers to carry out efficacy interventions in marginal population.

Estudio de la cobertura vacunal e intervención con agentes de salud comunitarios en población infantil marginal gitana de Alicante / Vaccine coverage study and intervention with health community agents in a marginal gypsy community of Alicante

Objetivo. Medir la cobertura vacunal del colectivo infantil marginal gitano de los asentamientos Parque Ansaldo, Montoto, Casa Larga, Cabrera Vicario, San Antón y Travesía del Canal, y su evolución después de la intervención mediante agentes de salud comunitarios gitanos, especialmente preparados para dicha intervención. Diseño. Estudio descriptivo, pretest-postest sin grupo control. Emplazamiento. Comunitario. Atención primaria. Participantes. Cuatrocientos sesenta y tres niños marginales gitanos menores de 15 años. Mediciones y resultados principales. Programa de educación y actuación sanitaria mediante visitas domiciliarias. La duración del proyecto fue del 1 de octubre de 1996 al 1 de octubre de 1997 y del 1 de octubre de 1998 al 1 de octubre de 1999. La cobertura vacunal antes de la intervención era para polio, difteria (D) y tétanos (T) del 41 por ciento, para tos ferina del 24 por ciento y triple vírica del 36 por ciento. Después de la intervención la cobertura global aumentó un 17 por ciento, siendo para polio, difteria y tétanos del 53 por ciento, tos ferina del 45 por ciento y triple vírica del 54 por ciento. Conclusiones. Cabe señalar las bajas coberturas vacunales encontradas y el aumento global después de la intervención en un 17 por ciento. De la intervención concluimos también la necesidad de colaboración entre las asociaciones gitanas, los centros de atención primaria y los centros de salud pública para llevar a cabo intervenciones eficaces en poblaciones marginales (AU)

Design of cassette vectors permitting cloning of all types of human TCR variable alpha and beta regions.

T cell clones are an irreplaceable asset for the study of immune responses relevant to human pathologies. Such cells, however, cannot always be maintained in long-term culture. In order to reconstitute functional human T cell receptors (TCRs) into stable and fast growing hybridoma T cells, we developed a general approach based on a versatile cassette system, which allows cloning of all types of human T cell receptor variable alpha and beta region genes fused to murine constant regions. These chimeric constructs are easily excised and transferred into expression vectors that can be used to transfect a human CD4-expressing murine T cell hybridoma recipient. The resulting transfectants are highly stable both in terms of T cell receptor-CD3 expression and IL-2 response to the specific antigenic stimulus. Using these cassette vectors, we reconstituted the original HLA-restricted antigen specificity for two human T cell clones, one recognizing an immunodominant epitope of HIV-1 gp120, and the other recognizing an immunodominant epitope of HIV-1 reverse transcriptase. We found that the reconstituted hybridomas maintain the ability of the original T cell clones to recognize the appropriate epitope in the context of the relevant MHC either as a synthetic peptide or after processing. Their unlimited growth capacity makes them particularly suited for in vitro studies.

Unbalanced expression of HLA-A and -B antigens: a specific feature of cutaneous melanoma and other non-hemopoietic malignancies reverted by IFN-gamma.

Conflicting evidences suggested that levels of HLA-A and -B antigens expressed on normal and neoplastic cells of given individuals are genetically predetermined, or, on the other hand, regulated by molecular mechanisms generating the down-regulated expression of HLA-B antigens frequently observed on melanoma cells. In our study, we quantitated, both at the protein and mRNA level, the amounts of HLA-A and -B antigens constitutively expressed on 23 primary cultures of metastatic melanomas and on autologous peripheral blood mononuclear cells (PBMC). Flow cytometric analyses identified a significantly (p < 0.01) lower expression of HLA-B antigens on melanoma cell cultures but not on autologous PBMC. Consistently, lower amounts of HLA-B antigens mRNA were detected by RNase protection assay exclusively in neoplastic cells. This unbalanced expression of HLA-A and -B antigens was readily reverted by interferon (IFN)-gamma but not by the DNA hypomethylating agent 5-aza-2'-deoxycytidine in 4 melanoma cell cultures investigated. Significantly (p < 0.05) lower levels of HLA-B antigens were also detected on cells from solid malignancies of different histotypes but not on neoplastic cells from hemopoietic neoplasms; levels of HLA-B antigens were rapidly up-regulated by IFN-gamma exclusively on non-hemopoietic transformed cells. Together, these data strongly argue against a genetic predetermination of the amounts of HLA-A and -B antigens expressed on normal and neoplastic cells of distinct melanoma patients and suggest that constitutively low levels of HLA-B antigens are a specific feature of non-hemopoietic transformed cells that is controlled by common regulatory mechanism(s) and that is possibly shared by non-hemopoietic normal cells.

In vitro immunization with a recombinant antigen carrying the HIV-1 RT248-262 determinant inserted at different locations results in altered TCRVB region usage.

Immunodominance or cripticity of a peptide-borne determinant may be influenced by the protein context in which the epitope is embedded. In this frame, we previously showed that certain human T cell clones, derived from different donors, may differentially recognize the RT248-262 helper determinant depending on whether it is provided to the presenting cells as a synthetic peptide or as a recombinant carrier protein to which the sequence of interest is fused. We now report that, upon in vitro immunization of human PBL with autologous APC, the epitope-specific TCRVB repertoire obtained when selection is applied by pulsing the APC with the cognate synthetic peptide is different from that found when a recombinant protein is used in which the antigenic sequence is placed at either a N-terminal or C-terminal location of the GST carrier. As the TCRVB distribution is not a function of the APC used, we propose that processing of different recombinant molecules containing the same epitope may generate MHC/peptide complexes which, being antigenically diverse, may recruit distinct TCR specificities. These findings may be relevant for evaluating and predicting the immunogenic potential of subunit vaccines based on synthetic peptides or on recombinant proteins as compared to the native antigen.

Endoclip-assisted resection of large pedunculated colon polyps.

BACKGROUND: Large pedunculated colorectal polyps are often difficult to remove endoscopically. METHODS: Four patients with giant pedunculated polyps (>3 cm) underwent an endoscopic procedure in which the polyp stalk was ligated with multiple clips and resected with a needle-knife papillotome. RESULTS: No complications occurred either during or immediately after the procedure. Mean size of the resected polyps was 4.8 +/- 1.2 cm (range 3 to 6 cm). Mean time for the entire procedure was 31 +/- 5 minutes (range 25 to 45). No bleeding was found after a mean follow-up period of 4.3 +/- 1.1 months (range 3 to 6 months). CONCLUSIONS: Although technical refinements are necessary to make the procedure easier and faster, this approach might represent the only option for selected patients who would otherwise need surgical resection of large pedunculated colonic polyps.

Recognition of HIV-derived B and T cell epitopes displayed on filamentous phages.

The amino acid sequence of HIV reverse transcriptase (RT) from residue 248 to residue 262 was expressed on the surface of filamentous phage fd, fused to the major coat protein gVIIIp. The chimeric phage was used to assess the ability of anti-RT (248-262) human T cell lines and clones to become activated by the phage-displayed peptide. The RT peptide displayed on phage was recognized by the T-cells and induced production of Abs. However, not all T cells raised against the synthetic RT (248-262) peptide could respond. Lack of recognition did not depend on differences in the ability of different APCs to present the phage, but was apparently determined by the TCR specificity. The results presented here may be relevant to the design of recombinant protein-based subunit vaccines.

The Rho-family GTP exchange factor Vav is a critical transducer of T cell receptor signals to the calcium, ERK, and NF-kappaB pathways.

Vav is a GTP/GDP exchange factor (GEF) for members of the Rho-family of GTPases that is rapidly tyrosine-phosphorylated after engagement of the T cell receptor (TCR), suggesting that it may transduce signals from the receptor. T cells from mice made Vav-deficient by gene targeting (Vav-/-) fail to proliferate in response to TCR stimulation because they fail to secrete IL-2. We now show that this is due at least in part to the failure to initiate IL-2 gene transcription. Furthermore, we analyze TCR-proximal signaling pathways in Vav-/- T cells and show that despite normal activation of the Lck and ZAP-70 tyrosine kinases, the mutant cells have specific defects in TCR-induced intracellular calcium fluxes, in the activation of extracellular signal-regulated mitogen-activated protein kinases and in the activation of the NF-kappaB transcription factor. Finally, we show that the greatly reduced TCR-induced calcium flux of Vav-deficient T cells is an important cause of their proliferative defect, because restoration of the calcium flux with a calcium ionophore reverses the phenotype.

Prospective comparison of argon plasma coagulator and heater probe in the endoscopic treatment of major peptic ulcer bleeding.

BACKGROUND: Argon plasma coagulator was prospectively compared with heater probe in patients with bleeding peptic ulcers. METHODS: Forty-one patients with major stigmata of ulcer hemorrhage were randomly assigned to receive either heater probe (n = 20) or argon plasma coagulation (n = 21) treatment; 40% had active bleeding and 60% had a nonbleeding visible vessel in the ulcer crater. The two groups were similar with respect to all background variables. Episodes of recurrent bleeding were retreated with the same modality as used previously. Patients in whom treatment or retreatment failed underwent emergency surgery. RESULTS: Initial hemostasis (95% vs. 95.2%), recurrent bleeding (21% vs. 15%), 30-day mortality (5% vs. 4.7%), and emergency surgery (15% vs. 9.5%) were comparable in the heater probe and argon plasma coagulation groups, respectively. Argon plasma coagulation provided faster hemostasis (mean 60 +/- 19 vs. 115 +/- 28 seconds, p < 0.05). CONCLUSIONS: Argon plasma coagulation is safe and effective. Larger studies in patients with bleeding peptic ulcers are needed to confirm these promising results.

Peripheral intrahepatic cholangiocarcinoma: ultrasound findings and differential diagnosis from hepatocellular carcinoma.

OBJECTIVE: Peripheral cholangiocarcinoma may be more frequent than expected, and is usually asymptomatic until it is well advanced. Our purpose was to assess the accuracy of ultrasound in differential diagnosis. METHODS: We compared the sonographic findings of ten consecutive patients with histologically proven peripheral cholangiocarcinoma with those obtained in 26 consecutive patients with hepatocarcinoma detected in the same period. In every patient we performed an ultrasound-guided biopsy with a fine (22 gauge) cutting needle. RESULTS: In all patients with a final diagnosis of peripheral cholangiocarcinoma, the ultrasound scan disclosed multiple well-defined nodules with a hypoechoic or target pattern. Two patients had dilated intrahepatic bile ducts and suspected infiltration of the common duct. No patient had ascites. Only minimal alterations in laboratory examinations were found. Ultrasound-guided fine cutting needle biopsy yielded diagnostic material and allowed the definitive differential diagnosis. CONCLUSION: Peripheral cholangiocarcinoma even in Western countries may represent a significant proportion of all primary liver cancers. Due to non-specific symptomatology only intractable and far advanced cases were detected by means of sonography. Ultrasound findings did not differ from those found in cases of metastases from extrahepatic adenocarcinomas or hepatocarcinoma with multinodular pattern (10/26 in our series).

Emergency endoscopic ligation of actively bleeding gastric varices with a detachable snare.

BACKGROUND: Bleeding gastric varices (BGV) is a challenging condition whose management remains controversial and often empirical. METHODS: Over the past 6 months, emergency ligation of BGV was performed in seven cirrhotic patients (five men, two women; age range 47 to 70 years) using a detachable snare. Child's grade was B in two and C in five patients. Two patients had a concurrent hepatocellular carcinoma. Three patients had been previously treated with either balloon tamponade or injection sclerotherapy for bleeding esophageal varices. RESULTS: Hemostasis was achieved in all patients. Morbidity consisted of fever in one case. Six snares passed spontaneously, one was removed from the stomach on follow-up examination. Post-ligation ulcers were detected in all patients after treatment (mean diameter 7.4+/-2.1 mm) with no stigmata of recurrent hemorrhage. No early rebleeding was observed during hospital stay. On a mean follow-up of 3.8 months (range 2 to 6 months), no digestive hemorrhage was recorded. Ligated gastric varices were significantly 'reduced in size in four patients. CONCLUSIONS: Emergency ligation with detachable snare is feasible and may be an alternative life-saving method of endoscopic hemostasis in BGV.

Identical T-cell receptor beta chain rearrangements are present in T cells infiltrating the jejunal mucosa of untreated celiac patients.

The intestinal mucosal lesion in celiac disease is characterized by a predominant T-cell infiltration of both epithelium and lamina propria. However, a restricted use of T-cell receptors (TCR) in T lymphocytes infiltrating the jejunal mucosa of celiac patients has not been reported. Based on an immunohistochemical survey of jejunal biopsies from a cohort of untreated celiac patients, we demonstrated a small but significant increase of V beta 8.1/2+ T cells in the lamina propria, but not in the epithelium nor in the peripheral blood. Sequence analysis indicated the existence of a variable degree of clonality of V beta 8+ T cells in the celiac mucosa. More importantly, the recurrence of identical CDR3 regions in some patients was also observed. The altered distribution of V beta 8+ T cells and the presence of identical CDR3 regions in celiac patients, but not in controls was independently confirmed by CDR3 size analysis in a further cohort of patients. These findings suggest that disease-specific variations of the TCRBV8 repertoire are present in the small intestinal mucosa of untreated celiac patients.

Polymorphism in the 5' terminal region of the mRNA of HLA-DQA1 gene: identification of four groups of transcripts and their association with polymorphism in the alpha 1 domain.

Relative to other loci in the MHC, the HLA-DQ locus exhibits an exceptional degree of polymorphism of both A1 and B1 genes, particularly in the region coding for alpha and beta chains. Diversification of the association between different alpha and beta molecules either in cis or in trans contributes to the structural diversity of the repertoire of cell-surface class II protein's in the population. In addition, structural allelic polymorphisms in the 5' regulatory region of both DQB1 and DQA1 shows several linkage groups with respect to the allelic coding sequence of the respective genes. We describe here the allelic polymorphism in the DQA1 mRNA structure located at the 5' untranslated terminal region. This portion of the mRNA molecule represents, in many genes, a cis-acting regulatory sequence playing a role in the posttranscriptional mechanisms by which gene expression can be modulated. Based on detailed transcriptional analysis, we have been able to define at least four groups of transcripts in DQA1. The mRNA variability was associated with the polymorphism of the second exon of the DQA1 gene, coding for the alpha 1 domain and not with the DNA polymorphism in the 5' regulatory region.

Endoscopic retrieval of a surgical gauze from the common bile duct.

Non-parasitic foreign bodies in the common bile duct are rare and usually require laparotomy. We report the successful removal by endoscopy of a surgical gauze seven years after a simple cholecystectomy. The foreign body had been cholangiographically misdiagnosed as a large stone. The possibility of a foreign body that has migrated into the common bile duct should be considered in patients with cholangitis. Endoscopic sphincterotomy is the procedure of choice, though other extraction techniques may occasionally be necessary.

Anaplastic large cell lymphoma (CD30+/Ki-1+). Analysis of 35 cases followed at GISL centres.

Between January 1988 and June 1992, 35 patients with primary anaplastic large cell lymphoma (ALCL)CD30+ were referred to one of the institutions participating in GISL (Gruppo Italiano per lo Studio dei Linformi). 16 patients were treated with ProMACE-CytaBOM, two with MACOP-B, one with CHOP and one with LSA2-L2. As of November 1990, all newly diagnosed patients were treated with MOPP/EBV/CAD hybrid. 27 (77%) cases of ALCL CD30+ and 8 (23%) cases of Hodgkin's-related (HR) lymphoma CD30+ were diagnosed. Extranodal disease was present in 22 cases (63%), and 8 patients (23%) had primary bone marrow involvement. Twenty-three complete remissions (CR) (66%), six partial remissions (PR) (17%) and six no remissions (NR) (17%) were achieved with induction therapy. Results achieved with ProMACE-CytaBOM and MOPP/EBV/CAD hybrid were comparable. The overall response rate (CR+PR) was 85% for patients with classic ALCL CD30+ and 87% for those with HR lymphoma CD30+. The 3 year estimated overall survival rate was 66% and the 3 year relapse free survival rate was 65% for the entire group. The only significant favourable prognostic factor was the achievement of CR with initial therapy. Our findings suggest that ALCL (CD30+/Ki-1+) has a clinical outcome similar to aggressive non-Hodgkin's lymphoma (NHL). The use of an anthracycline-containing regimen will provide a change of cure in approximately 65% of cases.

A gene encoding a putative membrane protein homologous to the major facilitator superfamily of transporters maps upstream of the beta-glycosidase gene in the archaeon Sulfolobus solfataricus.

We have identified a gene encoding a putative membrane protein homologous to the major facilitator superfamily, mapping upstream of the lacS gene in Sulfolobus solfataricus. Permeases from this family mediate secondary transport and are widely distributed among eubacteria and eukaryotes; the finding of an archaeal member suggests that this mechanism of transport evolved before the divergence of the three living domains. We also report a transcriptional mapping of the gene cluster.