In vivo comparison of two through-plane MR velocity mapping methods: Fast fourier encoding and phase mapping

Magnetic resonance imaging maps of velocity were acquired with a 1.5-T system in 10 subjects in a plane perpendicular to the main pulmonary artery. Velocity images were successively acquired with a method developed from Fourier-encoding velocity imaging (FEVI) principles with eight gradient steps and one excitation, and with two-point phase-subtraction mapping. Reconstruction in FEVI was implemented by zero-filling interpolation around the eight gradient steps and then around the four central steps. The methods were compared by using estimates of noise in velocity measurements based on the difference between the experimental map and a smooth fitted map. For the same acquisition time, FEVI with four encoding steps was more precise in velocity measurements than phase mapping. Precision was further increased by the use of eight encoding steps, but acquisition time was doubled.     

Evaluation of two colored latex kits, the Wellcolex Colour Salmonella Test and the Wellcolex Colour Shigella Test, for serological grouping of Salmonella and Shigella species.

Two colored latex kits (the Wellcolex Colour Salmonella Test [WCT-Salmonella] and the Wellcolex Colour Shigella Test [WCT-Shigella]; Division Diagnostics, Laboratories Wellcome S.A., Paris, France), which allow identification of the most frequently encountered Salmonella serogroups and Shigella species, respectively, were evaluated. WCT-Salmonella and WCT-Shigella yielded sensitivities of 98.4 and 98%, respectively, and a specificity of 100% when they were tested on pure cultures received at a reference laboratory.     

Immunoglobulin G antibodies in human vaginal secretions after parenteral vaccination.

The induction of antibodies in vaginal secretions by systemic (intramuscular) immunization in humans was investigated by using the tetanus toxoid vaccine. Five women, 30 to 40 years old, were injected with a currently used dose of toxoid (40 IU), and serum, saliva, and vaginal secretion samples were collected on day 0 and on day 6 or day 10. All of these subjects had been previously vaccinated at least 5 years before; four were in good health, whereas one suffered from AIDS in clinical category B3. In most cases, analysis of specific antibodies in the vaginal wash showed a dramatic rise after boosting. These antibodies were primarily of the immunoglobulin G (IgG) isotype. The specific activity (ratio of antibody titer to IgG concentration) was shown to increase after the booster injection, irrespective of variations in the IgG level during the menstrual cycle. Comparison between serum and genital antibodies showed no difference in terms of both specific activity and level of avidity. These results demonstrate that parenteral injections can induce a systemic-derived antibody release in the vaginal fluid. Hence, systemic vaccinations can be efficient at the genital level and thus could reinforce or even replace a local vaccine.     

Spontaneous angina caused by spasm of the left coronary artery]

A 42 year old woman presented with a one year history of retrosternal chest pain and back pain on effort and at rest sometimes accompanied by minor syncopal attacks. Transient atrioventricular block was documented during one such episode associated with hypotension. Coronary angiography showed spontaneous spasm of the left main coronary artery with clinical symptoms but no electrocardiographic changes. The spasm was relieved by injection of SIN-1. The similarity between the previous clinical symptoms and those observed at coronary angiography was in favour of the diagnosis of spasm of the left main coronary artery without atherosclerotic coronary disease. Treatment with calcium atherosclerotic coronary disease. Treatment with calcium blockers and platelet antiaggregants led to total regression of her symptoms with a follow-up of 5 months.     

Epidemiological markers for epidemic strain and carrier isolates in an outbreak of nosocomial oxacillin-resistant Staphylococcus aureus.

An outbreak of nosocomial infections occurring in a postoperative intensive care unit was caused by a single strain of oxacillin-resistant Staphylococcus aureus. Six patients were infected, or colonized, by this strain, which was traced by using the following four epidemiological markers: antibiogram, bacteriophage type, capsular polysaccharide type, and esterase electrophoretic type. This strain was compared with S. aureus isolates obtained from the noses of 13 carriers from a group of 42 staff members. A good correlation in terms of phenotypic markers was found between the epidemic strain and a strain isolated from one carrier. Both exhibited the same pattern of multiple resistance as well as the same phage type, 77, capsular polysaccharide type, 5, and esterase electrophoretic type, 6. In contrast, an oxacillin-resistant strain, isolated from another carrier, differed from the epidemic strain by susceptibility to rifampin and by susceptibility to four additional bacteriophages. The other 11 strains isolated from carriers were susceptible to oxacillin and exhibited widely different phenotypes. These results confirm the interest of using several epidemiological markers to trace the spread of epidemic S. aureus strains and to delineate the carrier strains.     

Natural polyreactive secretory immunoglobulin A autoantibodies as a possible barrier to infection in humans.

Secretory immunoglobulin A (S-IgA) was investigated in human secretions for the presence of natural antibodies (Abs) acting as the first "immune barrier" to infection before induction or boosting of specific responses. These molecules could be the secretory counterpart of the natural Abs in serum that were previously shown by our laboratory to be polyreactive to autoantigens. Significant levels of S-IgA Abs to human actin, myosin, tubulin, and spectrin were detected in 10 saliva and 8 colostrum samples from normal subjects. Computer-assisted analysis of immunoblots of extracts from human muscles showed these Abs to react with a large number of autoantigens. Their polyreactivity was confirmed by cross-inhibition and by immunoblotting studies of affinity-purified natural Abs, assayed against a large variety of surface or secreted antigens from Streptococcus pyogenes. The thiocyanate elution method showed that functional affinities of some natural Abs can be of the same order of magnitude as those of tetanus vaccine antitoxins. Moreover, nonimmune binding of these natural Abs to the gut protein Fv (Fv-fragment binding protein) can enhance their effector functions. This demonstrates that human secretions contain polyreactive auto-Abs which can also react with pathogens. These secretory Abs of "skeleton key" specificities are possibly produced by a primordial B-1-cell-associated immune system and can be involved in a plurispecific mucosal protection against pathogens, irrespective of the conventional immune response.     

Genetic restriction of murine hepatitis virus type 3 expression in liver and brain: comparative study in BALB/c and C3H mice by immunochemistry and hybridization in situ

Summary To study the host-dependent genetic variations in murine hepatitis virus type 3 (MHV 3) induced diseases, we localized the sites of MHV 3 (Mill Hill strain) expression within liver and brain by immunohistochemistry or hybridization in situ. Two strains of mice were studied: BALB/c mice, which develop an acute and lethal hepatitis and C3H mice which develop a chronic brain infection. In BALB/c mice, viral RNA and antigens appeared during the first 24 h post infection (p.i.) in liver, whereas viral RNA was barely detectable in brain, up until death at day 3 p.i. In C3H mice, viral RNA and antigens were detected simultaneously in liver and brain only at day 2 p.i. In brain, the virus was detected in meningeal and ependymal cells and in perivascular cortical areas (days 5 and 7 p.i.). After day 49, the virus was no longer detected in brain parenchyma, but persisted in meningeal cells. Two host-dependent genetic differences in viral processing were observed in the liver: (1) the virus was first detected in Kupffer cells in BALB/c mice and mostly in hepatocytes in C3H mice; (2) in BALB/c mice, the 180 kDa S viral glycoprotein appeared more frequently cleaved in 90 kDa form than in C3H mice.     

Restricted association between biotypes and serotypes within group A streptococci.

Investigating individual variations between different isolates of group A streptococci, we observed a close correlation between biotypes and serotypes in 46 strains from pharyngitis patients. Biotyping, carried out with a commercially available rapid identification gallery, delineated 10 different associations of characteristics, designated biotypes 1 to 10, observed both in the manufacturer's (127 strains) and our personal (98 strains) collections of group A strains. Only the most frequent biotypes (biotypes 1 to 6) were observed in the pharyngitis cohort, but the overall frequencies of the biotypes did not display striking differences compared with the control collections. Serotyping of the pharyngitis strains showed that each M type was restricted to a sole biotype. For example, M types 1, 4, and 28 were found only in biotype 1 and M type 6 was found only in biotype 6 strains. This association was not due to an epidemiologic bias, since it was also observed in a control series consisting of reference strains and isolates from distant countries (the United States and Czech Republic versus France). An exception was for M type 78, which exhibited biotype 3 or biotype 4. Investigation of the heterogeneity of the strains at the DNA level showed no significant variations of the ribotype patterns between strains of different biotypes, confirming that group A streptococci belong to a unique and homogeneous species. This previously undescribed association between serotypes and biotypes is of interest for a rapid and preliminary characterization of strains isolated in individual patients or during an outbreak. A possible pathogenic association of some biotypic characteristics with specific M proteins is envisaged.