Characterization of Paracoccidioides brasiliensis isolates by random amplified polymorphic DNA analysis.

We initially used 25 different random primers in order to test their ability to generate random amplified polymorphic DNA fragments from the dimorphic human pathogenic fungus Paracoccidioides brasiliensis. From the tested primers we chose five to distinguish between seven isolates of this microorganism. The DNA amplification patterns allowed clear differentiation of the seven isolates into two distinct groups with only 35% genomic identity. One of these groups contained two subgroups with 81% genetic similarity. The random amplified polymorphic DNA analysis method proved to be a good tool for analyzing and comparing different genomes of P. brasiliensis isolates.     

Induction of HLA-DR expression on thyroid follicular cells by cytomegalovirus infection in vitro. Evidence for a dual mechanism of induction.

Cytomegalovirus (CMV) infection of primary cultures established from human thyroid nodular and normal (paranodular) tissues resulted in induction of human leukocyte antigen (HLA) DR expression on thyroid follicular cells (TFC), as detected by cell-surface immunofluorescence staining with monoclonal antibodies (MAb). Two distinct modalities of induction were observed. The first type occurred in cultures of normal tissue obtained from CMV-seropositive but not seronegative donors, was detected on 30% to 50% of the TFCs, even though the vast majority of these cells failed to show any morphologic or antigenic evidence of individual CMV infection, and was associated with production of gamma-interferon (gamma-IFN) in vitro. The induced molecules displayed the characteristic DR polypeptide profile on immunoprecipitation and electrophoretic analysis. These results demonstrate that CMV infection of normal thyroid cultures may induce DR expression on TFCs in the absence of pre-existing lymphoid infiltrates and suggest that the induction is the result of an in vitro response to CMV by previously sensitized immunocompetent cells present in these primary cultures. Such a response, associated with the release of gamma-IFN, would induce DR expression on neighboring uninfected cells. The second mode of induction occurred in all CMV-infected cultures, regardless of their tissue origin (nodular or normal) or the serologic status of the donors. Up to 50% of infected TFCs at a late stage of infection, having fully developed CMV antigen-positive intranuclear inclusions, also displayed the cell-surface DR-related determinant recognized by one of the four anti-DR MAbs used. This induction was restricted to TFCs, while CMV-infected fibroblastoid cells present in the monolayers were invariably negative. Induction by CMV of major histocompatibility class II antigens on human epithelial cells may have significant implications in the development of normal immune responses against local viral infection, the enhancement of alloimmune rejection of grafted organs, and the generation of organ-specific autoimmune responses.     

The rheumatic patient''s early needs and expectations

During the last few years, studies have revealed that the need for psychosocial support and concrete social services are great in the early stages of the treatment of rheumatic diseases. The ability to keep a job, to do household chores, to participate in leisure activities and to maintain social relations is clearly impaired. Anxiety and depression are not unusual and often associated with weak support from relatives, loneliness and disturbed family relations. Nevertheless, the patients report resilience and determination to cope with the impacts of illness. Crisis intervention, vocational guidance and counselling about problems concerning the disease should be available and offered to the patients. As the patients seem to be unaccustomed to talking about their psychosocial problems, an empathetic and information-seeking attitude on the part of the health care staff is essential.     

Preferential expansion of Ly-1 B and CD4 CD8 T cells in the polyclonal lymphocyte responses to murine T.cruzi infection

Acute murine infection with T.cruzi results in polyclonal lymphocyteresponses manifested by blast transformation of a large fractionof B, CD4+, and CD8+ cells. We describe here the finding ofsignificant increases in the splenic representation of minorpopulations, Ly-1+ B cells and CD4-CD8- T cells. These lymphocytepopulations might play an important role in the host response,as shown by T.cruzi infection of hosts that had been lethallyirradiated and reconstituted with autologous bone marrow. Underthese conditions, the splenic polyclonal PFC responses are nearlyabrogated, and not restored by the transfer of syngeneic peritonealcells which, however, reconstitute T15 idiotype production inthe same hosts. Control levels of PFC responses, however, arereconstituted by transfer of syngeneic splenic T cells. Sincebone marrow-reconstituted animals contain normal numbers ofCD4+ and CD8+ T cells which are actually activated by infection,these results suggest the participation of other T cell populationsin the host response to infection, as also suggested by themarked increases in T cell receptor and messages detectedin the spleen of infected animals. The implications of thesefindings in immunopathology of Chagas' disease are discussed.     

The effect of immunotherapy on eosinophil accumulation and production of eosinophil chemotactic activity in the lung of subjects with asthma during natural pollen exposure

Two groups of birch pollen--allergic patients with seasonal rhinoconjunctivitis and asthma were followed during two consecutive birch-pollen seasons, one group, N = 10, during a season with high pollen load, and one group, N = 15, during a season of low pollen load. Half the patients were treated with immunotherapy (IT) for 3 and 4 years, respectively. The other half of the patients served as control group (non-IT). Bronchoalveolar lavage (BAL) was performed once before each season and once during the pollen season. Eosinophil (EOS) numbers in BAL were increased (p less than 0.01) during the season with high pollen load but not in the season with a low pollen load, and this increment was absent in the IT-treated group. Also, the EOS cationic protein levels were raised in the non-IT-treated group during the season with a high pollen load. The levels of EOS and neutrophil chemotactic activity were raised in BAL in both seasons in the non-IT-treated group compared with the IT-treated group (p less than 0.02, p less than 0.003, p less than 0.04, and p less than 0.005 in high- and low-load pollen season, respectively). Serum and BAL eosinophil chemotactic activity (ECA) were positively correlated (p less than 0.001). We conclude that there is an influx of active EOSs into the lung of pollen-allergic patients with asthma during a pollen season, which may be abrogated by IT. Furthermore, the generation of ECA appears to be an extremely sensitive marker of antigenic exposure, and the potent inhibition of the generation of ECA by IT may provide a clue as to the mechanism of this treatment.     

Changes in peripheral energy metabolism during audiogenic seizures in rats

Plasma glucose and lactate, hepatic glycogen and epididymal adipose tissue lipogenesis and lipolysis were studied in Wistar audiogenic rats (WARs), a genetic model of epilepsy, under three experimental conditions, i.e., before, 3 min after and 10 min after seizures induced by intense sound exposure. Plasma glucose increased 3 min after the seizure onset and rose to a peak after 10 min. Hepatic glycogen decreased significantly in susceptible audiogenic rats compared to nonepileptic controls, even before sound stimulation. A marked ( approximately 10-fold) rise was observed in plasma lactate levels 3 and 10 min after the seizures compared to the response of the control group. Lipogenic activity showed a marked decrease even after stimulation with 25 ng/ml insulin. Based on these results, WARs showed reduced isoproterenol-stimulated lipolysis compared to control animals, whereas basal levels only differed significantly at 10 min after seizure activity. In conclusion, it can be inferred from these results that (a) the increase in plasma glucose after stimulation might result from sequential interaction of autonomic activation at seizure onset; (b) excessive muscular activity was at least partially responsible for the steady rise in plasma lactate concentrations; (c) audiogenic seizures, which increase adrenergic activity, induce desensitization of the beta-adrenergic lipolytic pathway in epididymal adipose tissue; (d) genetic selection for audiogenic seizure susceptibility results in pronounced alterations at multiple levels of metabolic regulation.     

Characterization and identification of an iron-oxidizing,Leptospirillum-like bacterium,present in the high sulfate leaching solution of a commercial bioleaching plant

Most copper bioleaching plants operate with a high concentration of sulfate salts, caused by the continuous addition of sulfuric acid and the recycling of the leaching solution. Since the bacteria involved in bioleaching have been generally isolated at low sulfate concentrations, the bacterial population present in the high-sulfate (150 gl(-1)) leaching solution, employed in a copper production plant, was investigated. The iron-oxidizing bacteria able to grow in the leaching solution were enriched by several batch cultivations and, after serial dilution, an abundant bacterial strain was isolated. This strain, called LA, exhibited a relatively constant rate of iron-oxidation in media containing sulfate ions at concentrations ranging from 10 to 150 gl(-1). Culture collection strains of Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans showed limited abilities to grow at sulfate ion concentrations higher than 70 gl(-1). In spite of its tolerance to high sulfate concentrations, strain LA was as sensitive to NaCl as A. ferrooxidans. Comparative sequence analysis of the 16S rRNA gene of strain LA indicated that it is phylogenetically related to strains described as Leptospirillum ferrooxidans. Bacterial community DNA restriction patterns of 16S rRNA genes suggested that strain LA was a minor component of the bacterial population present in leaching solution, but is abundant in ore leached with this solution.