New parachlamydial 16S rDNA phylotypes detected in human clinical samples

Chlamydiales are important intracellular bacterial pathogens, causing a wide variety of diseases in vertebrates, including humans. Besides the well-known species in the family Chlamydiaceae, new chlamydial organisms have recently been discovered, forming three new families: Parachlamydiaceae, Simkaniaceae and Waddliaceae. Parachlamydia acanthamoebae and Simkania negevensis are currently investigated as emerging human respiratory pathogens. Additional chlamydial lineages have been discovered by 16S rDNA-based molecular studies, and their implication in human infections is poorly known. By using a pan-chlamydia 16S rDNA PCR, we have searched for the presence of chlamydiae in 228 clinical samples that all previously had been shown to be PCR-negative for Chlamydophila pneumoniae: 170 respiratory samples, 45 atheromatic plaques and 13 peripheral blood mononuclear cell samples. Nine respiratory samples tested positive. Sequence analysis has allowed us to assign four sequences to Chlamydophila psittaci, three sequences to Chlamydophila felis, and two sequences to two novel phylotypes belonging to the Parachlamydiaceae. These latter sequences showed similarity values of more than 93% with each other and with the P. acanthamoebae sequence, thus belonging to novel, unrecognized species. In conclusion, this report showed that a variety of non-C. pneumoniae chlamydial respiratory infection is present in humans, and that new parachlamydiae distinct from P. acanthamoebae may be detected in human clinical samples. Future studies will be of interest in order to estimate the diversity of these novel chlamydiae in both clinical and environmental samples, as well as their possible clinical implication in human and animal infections.     

Modulation of visual cortical excitability in migraine with aura: effects of 1 Hz repetitive transcranial magnetic stimulation

Recent studies showed hyperexcitability of the occipital cortex in subjects affected by migraine with aura. It has been shown that 1 Hz repetitive transcranial magnetic stimulation (rTMS) reduces excitability of visual cortex in normal subjects. The aim of the study was to investigate the effects of low frequency (1 Hz) rTMS on visual cortical excitability by measuring changes in phosphene threshold (PT) in subjects with migraine with aura. Thirteen patients with migraine with aura and 15 healthy controls were examined. Using a standardized transcranial magnetic stimulation protocol of the occipital cortex, we assessed the PT (the lowest magnetic stimulation intensity at which subjects just perceived phosphenes) before and after a 1-Hz rTMS train delivered at PT intensity for 15 min. The difference in the proportion of subjects reporting phosphenes in migrainer and control groups was significant (migrainers: 100% vs controls 47%; P<0.05), and 1 Hz rTMS over the occipital cortex led to a significantly increased visual cortex excitability expressed as a decrease in PT in subjects affected by migraine with aura. Conversely, after a 1-Hz TMS train normal subjects showed increased PT values, which suggests a decreased visual cortex excitability. Our findings confirm that the visual cortex is hyperexcitable in migrainers and suggest a failure of inhibitory circuits, which are unable to be upregulated by low frequency rTMS.     

Ultrastructural localization of human HL-A membrane antigens by use of hybrid antibodies

The localization of HL-A histocompatibility antigens at the surface of human lymphocytes in electron microscopy has been studied using hybrid antibodies to bind electron-dense particles (ferritin and plant viruses) to anti-HL-A antibody. A discontinuous distribution of the markers is observed at the cell surface, which is identical with that described for H-2 antigens on mouse lymphocytes with the same technique. Double labelling experiments suggest that the areas of the cell surface where HL-A antigens are detected contain also the heterologous lymphocyte antigens detected by an anti-thymocyte serum and that HL-A antigens are not renewed at a detectable level during the period of the labelling procedure in the areas of the cell surface which are not labelled primarily with ferritin-anti-IgG-anti-HL-A complexes. The interpretation of the discontinuous labelling of HL-A antigens with direct immunoferritin techniques is discussed.     

Hypomethylation of the human HLA-DRα gene in breast carcinomas and autologous metastases

The methylation pattern of the human HLA-DR gene was analyzed in normal breast tissues, breast primary tumors and lymphonodal metastases isolated from patients carrying breast carcinomas. In breast adenomas and also in normal tissues (including breast, muscle, brain, sperm and T- and B-lymphocytes), the HLA-DR gene is hypermethylated at the CCGG and GCGC sites. In all tissues studied, the only constantly unmethylated region is located in the 5 portion of the gene, near the promoter sequence. Further, the results indicate that the HLA-DR gene is hypomethylated in carcinomas and in the relative metastatic lymph nodes. It is suggested that hypomethylation of the human HLA-DR gene could be proposed as a molecular marker of malignant breast tumors.     

Glial fibrillary acidic protein immunoreactive astrocytes in developing rat hippocampus.

The developmental pattern of glial fibrillary acidic protein (GFAP)-immunoreactive astrocytes was investigated in the hippocampus (subfields CA1, CA3 and CA4) and in the dentate gyrus of male and female rats aged 11, 16, 30, 90 and 150 days by immunohistochemistry associated with image analysis. Analysis was centred on stratum radiatum, a hippocampal area rich in GFAP-immunoreactive astrocytes. The volume of different portions of hippocampus, the number and the size of astrocytes, the intensity of cell body GFAP immunostaining as well as the extension of astrocyte were assessed. A maturation pattern consisting in higher cellular expression of GFAP, an increase in overall cell size and expanding arborisation from the 11th to the 30th postnatal day, followed by stabilisation of these parameters until the 90th day of life, and a subsequent decrease in the oldest age group studied was found. A sex-related different temporal pattern of astrocytes maturation in size and GFAP content was observed in the CA1 subfield only. The increase of GFAP content during pre-weaning ages was less pronounced in females than in males as well as the decrease between the 90th and the 150th day of age. Moreover, the size of astrocytes was larger in females than in males at the 11th and 150th days of life. These findings suggest that hippocampal astrocytes undergo rapid maturation in the 1st month of postnatal life, followed by a slow consolidation of this process until the 3rd month of life. At 5 months of age, there are still dynamic changes in the mature astrocytes, which become slender and thinner probably as a response to the increased volume of hippocampus noticeable at this age.     

Pharyngotonsillitis caused by Streptococcus pyogenes: clinical and epidemiological aspects and resistance phenotypes towards macrolides

During 2001 we analyzed 1730 pharyngeal swabs for S. pyogenes (SGA): 1142 children (0-10 years old), 132 adolescent subjects (11-17 years old), and 456 adults (18 or more years old). 994 subjects (664 children, 85 adolescent ones, 245 adults) had acute pharyngotonsillitis. In this last group we observed 321 positivities (32.3 %) for SGA: 40.4 % among children, 24.7 % among adolescent people, 13.1 % among adults. The pharyngotonsillitis prevailed during winter and spring. The resistances (R) towards erythromycin were 27.7 % (89 cases), and among children 30.6 % (82 cases), towards clyndamicin 15.3 % (49 cases, and 17.2 %, 46 cases, among children), towards rokytamicin 11.8 % (38 cases, and 13.1 %, 35 cases, among children). These were the phenotypes of R to erythromycin: 25.8 % M-phenotype, 19.1 % inducible (iMLS), 55.1 % constitutive (cMLS); among children respectively 25.6 %, 18.3 % and 53.7 %. Increased resistances towards 16-C macrolides, increased resistances of cMLS to erythromycin, and the persistence of R to 14-C macrolides around 30 % are discussed.     

The music of speech: music training facilitates pitch processing in both music and language

The main aim of the present experiment was to determine whether extensive musical training facilitates pitch contour processing not only in music but also in language. We used a parametric manipulation of final notes' or words' fundamental frequency (F0), and we recorded behavioral and electrophysiological data to examine the precise time course of pitch processing. We compared professional musicians and nonmusicians. Results revealed that within both domains, musicians detected weak F0 manipulations better than nonmusicians. Moreover, F0 manipulations within both music and language elicited similar variations in brain electrical potentials, with overall shorter onset latency for musicians than for nonmusicians. Finally, the scalp distribution of an early negativity in the linguistic task varied with musical expertise, being largest over temporal sites bilaterally for musicians and largest centrally and over left temporal sites for nonmusicians. These results are taken as evidence that extensive musical training influences the perception of pitch contour in spoken language.     

Kinetics of mitogen-induced proliferation and differentiation of human peripheral blood B lymphocytes.

Using a culture system that includes a B-enriched fraction of peripheral blood lymphocytes (PBL) mixed with non-proliferating "filler" cells (mitomycin-treated PBL or T cells), the kinetics of human B cell proliferation and differentiation into cells containing cytoplasmic immunoglobulin (cIg) have studied. Following stimulation with phytohaemagglutinin (PHA) or pokeweed mitogen (PWM), proliferative responses of enriched B cells were comparable to those for unseparated PBL, with a peak at 3 to 5 days and a steep decline thereafter; cIg-positive cells increased with both mitogens from day 3 until 7. Little proliferation or differentiation occurred in B cell cultures lacking T "filler" cells. The results indicate that human B cells can respond polyclonally to PHA in vitro, as well as to PWM, if non-proliferating T cell "help" is present. Further, these proliferative responses, but not subsequent differentiation, were inhibited by PHA-stimulated blasts that were treated with mitomycin and added on day 3 of culture.     

Automated spoken dialogue system for hypertensive patient home management

Recent advances in automatic speech recognition and related technologies allow computers to carry on conversations by telephone. We developed an intelligent dialogue system that interacts with hypertensive patients to collect data about their health status. Patients thus avoid the inconvenience of traveling for frequent face to face visits to monitor the clinical variables they can easily measure at home; the physician is facilitated in acquiring patient information and cardiovascular risk, which is evaluated from the data according to noted guidelines. Controlled trials to assess the clinical efficacy are under way.