[Study of immune response in pregnancy. I. Lymphocyte populations].
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Biomedical subjects
Publications and source records attributed to C Moreno.
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Bovine lung extract contained an enzyme or enzyme system that catalyzed the formation of 14,15-oxido-5,8,11-eicosatrienoic acid from phosphatidylinositol. The enzyme activity increased markedly during the course of purification, apparently due to the removal of two endogenous inhibitors from the enzyme. Using membranes with known molecular weight cut-offs, we estimated the Mr of Inhibitor 1 to be between 10,000 and 100,000 and Inhibitor 2 less than 1,000. Inhibitor 1 appeared to be partially inactivated by trypsin and was heat labile, whereas Inhibitor 2 was resistant to trypsin and was heat resistant. Both inhibitors were hydrophilic.
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A study has been undertaken in a unit of pediatric gastroenterology and nutrition. The unit also deals with general pediatric emergencies. The purpose of this study was to calculate the cost of hospitalization and the distribution of the cost between the different components: personnel expenses (medical and non-medical staff), cost of products used (enteral and parenteral nutrition included), cost of medicotechnical intervention. The study was carried out over a period of 28 days and included 117 hospitalized children. Only the expenses directly linked to the patient's care were taken into account. The exact time spent with each patient by every category of staff, the quantity of products and the treatment given had to be carefully recorded. The results reveal the share of the cost which goes to non-medical staff (about 60%), except when pathological cases need frequent and detailed investigations. Once the budget has been determined, department heads are required to play administrative role and this study underlines the process of cost build-up and thus enables a selective intervention in one sector or another of hospital expenses.
Lipoarabinomannan from Mycobacterium tuberculosis was able to inhibit antigen induced T cell proliferation of human CD4+ T cell clones specific for influenza virus. The inhibitory effect was also present when peripheral human T cells were stimulated with crude mycobacterial antigen extracts. Non-specific T cell stimulation, i.e. IL-2, PHA and anti-CD3 antibodies coupled to beads, was not affected. The inhibitory property was also found when arabinomannan and arabinogalactan of mycobacterial origin were tested but not with other unrelated polysaccharides used as controls. The effect appears to be related to the processing of the antigen by the antigen-presenting cells, since it was evident when T cell clones were stimulated with whole virus, whereas stimulation with a synthetic peptide containing the relevant epitope was not inhibitable.
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There has been a notable lack of success in producing an effective vaccine against Neisseria meningitidis group B infections, despite such prophylaxis being available for group A and C disease. The reasons for this are reviewed and evidence presented that a vaccine based on the group B capsular polysaccharide should be pursued. To be effective, a clear understanding of, and improvement in the poor immunogenicity of the polysaccharide is required. Consequently, the nature of the antigenic structure involved in immune recognition has been evaluated at the molecular level and reasons for the poor immunogenicity of the B polysaccharide are presented. Methods of increasing the immunogenicity are proposed with the intention of undertaking human volunteer trials.
Four murine monoclonal antibodies which reacted with a (2----8)alpha-linked sialic acid polysaccharide were produced. Three of the antibodies reacted specifically with Neisseria meningitidis serogroup B and Escherichia coli K-1 polysaccharide antigens, whereas one antibody cross-reacted with N. meningitidis group C polysaccharide antigen, a (2----9)alpha-linked homopolymer of sialic acid. By using the most avid antibody (MB 62), a latex particle agglutination test was developed which could detect capsular polysaccharide at 10 ng/ml. It also detected antigen in the cerebrospinal fluid (CSF) of all seven N. meningitidis group B- and two E. coli K-1-infected patients, whereas 57 control CSF samples, including 8 from neonates, were negative. Cultures of 21 N. meningitidis group B strains, 7 E. coli K-1 strains, and 1 Moraxella nonliquefaciens strain gave a positive result, whereas 53 strains from other serogroups were all negative. In a separate clinical evaluation, the overall sensitivity of the latex particle agglutination test was 81% (22 of 27) with fresh CSF samples, 48% (15 of 31) with stored CSF samples, and 94% (32 of 34) with blood cultures. No false-positive reactions were recorded with 165 control CSF samples, and the specificity with blood cultures was 99.4% (519 of 522).
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A series of (2----8)-alpha-, (2----9)-alpha-, and alternate (2----8)-alpha- and (2----9)-alpha-linked oligomers of sialic acid (N-acetylneuraminic acid, NeuNAc) was prepared by digestion with bacteriophage or by partial hydrolysis at pH 7.0 and 100 degrees of polymers of sialic acid produced by Neisseria meningitidis and Escherichia coli. The oligosaccharides were purified by gel filtration or by anion-exchange chromatography, and their chain lengths were determined by colorimetric measurement of the formaldehyde released from the non-reducing end residue after periodate oxidation, radiolabelling of the reducing end residue by reduction with borotritiide, and determination of the ratio of the non-reducing end and internal residues by g.l.c. of the trimethylsilyl derivatives of the methyl ester methyl beta-ketosides. 1H-N.m.r. spectroscopy was used to confirm the chain length of two oligosaccharides. These methods were used to determine the average chain-length of the sialic acid polysaccharides produced by N. meningitidis and E. coli and the percentage of chains with covalently bound lipid moieties at the reducing end.
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Previous studies have emphasized injury mechanism, wound site, and presenting vital signs as critical determinants for survival following penetrating cardiac injury. Our experience suggests pericardial tamponade is another crucial factor and is the basis for this study. Prognostic features were reviewed in 100 consecutive, unselected patients with acute cardiac injuries. Mechanism was stab wound in 57, and gunshot injury in 43. Location included right ventricle in 55, left ventricle in 49, right atrium in 16, and left atrium in seven. Overall salvage was 31%,; 27 (47%) of 57 stab wounds, four (9%) of 43 gunshot wounds, 22 (49%) of 45 right, and nine (23%) of 39 left heart wounds. The presence or absence of pericardial tamponade was documented in 77 patients. Patients with tamponade had a survival of 73% (24/33) compared to 11% (5/44) in those without its protective effect. The presence of tamponade improved survival (p less than 0.05) following stab injuries (77% vs. 29%), gunshot wounds (57% vs. none), right heart wounds (79% vs. 28%), left heart injuries (71% vs. 12%), and overall in patients arriving with vital signs (96% vs. 50%). Multivariant discriminant analysis by logistic regression demonstrated cardiac tamponade was a critical independent factor in patient survival, and suggested that it may be more influential than presenting vital signs in determining outcome.
Definitive treatment of life-threatening hemorrhage associated with blunt pelvic fracture remains controversial. To elucidate this issue, we reviewed 538 consecutive patients admitted with acute pelvic fracture during a 5-year period. Injury mechanism was motor vehicular in 214 (40%), falls in 152 (28%), auto-pedestrian in 92 (17%), motorcycle in 46 (9%), crush in 26 (5%), and assault or skiing in eight (1%). Ninety-two (17%) of these patients required greater than 6 units of blood transfusion during the first postinjury day, and are the primary focus of this report. Twenty-five patients (28%) had unilateral anterior (Group I, n = 20) or posterior (Group II, n = 5) fractures. The remaining 67 patients (72%) had anterior and posterior element involvement on the same side (Group II, n = 38), bilaterally (Group IV, n = 14), or open perineal wounds (Group V, n = 15). The PASG was applied in 47 patients (51%), and controlled hemorrhage in 12 (71%) of the 17 in whom it was used alone to tamponade pelvic bleeding. Peritoneal lavage was performed in 73 patients (79%). Initial aspirate yielded gross blood in 32 patients; 27 (84%) of these required urgent laparotomy. External skeletal fixation was applied in 19 patients; bleeding was controlled in 18 (95%). Pelvic angiography identified active hemorrhage in three patients and selective embolization was successful in two. Sixty-eight (74%) of the high-risk patients survived. Thirteen (54%) of the 24 deaths were attributable to the pelvic trauma, ten were due to recalcitrant bleeding, and three to delayed sepsis.(ABSTRACT TRUNCATED AT 250 WORDS)
Athymic mice were capable of producing IgM antibodies to B polysaccharide of N. meningitidis when immunized with the polysaccharide complexed to outer membrane proteins, whereas no immunogenicity could be demonstrated with the purified polysaccharide. Transfer of T cells to athymic cells demonstrated that the primary anti-B response was truly thymus-independent but the bulk of the secondary response was thymus-dependent. Transfer of T and B cells purified from spleens of immune mice into irradiated recipients showed the presence of memory T cells, but no memory B cells could be found.
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Affinity maturation was studied by the analysis of the kinetics of the appearance of antibody subpopulations with different affinities during the immune response, using an hapten-inhibition ELISA. The immune response in KLH-Ar-immunized A/J mice was used as a model system. Five antibody subpopulations of different affinity (10(3)-10(7) M-1) could be detected, the relative concentrations of which changed during affinity maturation. The high-affinity antibody subpopulations did not represent the major fraction at any stage during affinity maturation. The appearance of the highest affinity subpopulation (10(7) M-1), despite exhibiting relative concentrations no higher than 12%, produced an important increase in average affinity. On the other hand, its disappearance at the end of the maturation process could explain the average affinity decrease observed at this stage. Our results indicate that affinity maturation cannot be explained by the dominance of high-affinity clones, as proposed by Siskind & Benacerraf (1969). The increase in affinity could rather be due to the progressive appearance of low percentages of high-affinity clones, which are not present in the primary response and never become dominant.