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A Solari

Publications and source records attributed to A Solari.

At least 55 records · Page 3Linked to original sources
PubMed1998

Lytic antibodies in Trypanosoma cruzi-infected persons with low parasitemia.

An antibody-dependent, complement-mediated lysis test performed with three Chilean trypomastigote strains used as target cells revealed strain dependence in the detection of lytic antibodies in chronic chagasic sera. The highest percentage of lytic sera was observed when MF or V115 strains were used as target cells (90% and 71%, respectively) in the chronic chagasic group with negative xenodiagnosis results. No significant statistical association was observed between lytic activity in chronic chagasic sera and the presence or absence of cardiopathy (P > 0.01). Western blot analysis showed that lytic sera recognize different antigens depending on the strain used and nonlytic sera had a weaker capacity to detect them.

Animals↗
PubMed1997

Individual diurnal plasma profiles of thyroid hormones in rainbow trout (Oncorhynchus mykiss) in relation to cortisol, growth hormone, and growth rate.

In order to characterize the individual diurnal plasma profiles of triiodothyronine (T3) and thyroxine (T4) in rainbow trout (Oncorhynchus mykiss), blood samples from 41 fish were taken every hour during a 24-hr period, through a catheter inserted into the dorsal aorta. The possible influences of day-night alternation, sex, and diet (feed intake, time of meals) on thyroid hormone (TH) profiles were analyzed. The existence of relations between diurnal plasma profiles of T3, T4, T3/T4 ratio, and those of the growth hormone (GH), cortisol (previously described in Gomez et al., J. Exp. Zool. 274, 171-180, 1996), and the growth rate was monitored. Average daily T3 and T4 concentrations were, respectively, 2.6 +/- 0.2 and 5.5 +/- 0.3 ng/ml (n = 41). Our study showed little or no variation in plasma T3 concentrations during one 24-hr period, while those of T4 fluctuated markedly. T4 peaks occurred from a baseline of 4.0 +/- 0.2 ng/ml at a frequency of 2.5 +/- 0.2 peaks/24 hr, with an amplitude of 3.0 +/- 0.4 ng/ml, and a duration of 4.3 +/- 0.4 hr. There was a significant difference between the average circulating T3 level during the day and that at night (2.4 +/- 0.2 vs 2.7 +/- 0.2 ng/ml). No influence of sex or food factors was observed on daily TH concentrations. TH peaks occurred irregularly and asynchronously without apparent influence of day-night alternation, sex, and diet. The growth rate was significantly correlated with the daily T3 concentration (r = 0.77), but not with T4. No significant relationships were found between daily concentrations of T3, T4, GH, and cortisol. The absence of a relationship between TH and GH concentrations suggests that, in salmonids, GH may have no observable short-term action on the conversion of T4 to T3.

Animals↗
PubMed1997

Molecular karyotype and schizodeme analyses of Trypanosoma cruzi stocks from Chilean triatomines.

Forty-one Trypanosoma cruzi stocks isolated from the Chilean vectors Triatoma infestans and Triatoma spinolai were characterized by pulse-field gel electrophoresis and Southern blotting with the cruzipain gene, and by schizodeme analysis of kinetoplast DNA with EcoRI and Msp I. Seven parasite groups were found by molecular karyotype which correlate with schizodeme and multilocus enzyme electrophoresis, supporting the concept of clonal propagation for Trypanosoma cruzi. A predominant T. cruzi stock was isolated from domiciliary T. infestans in several geographical areas of Chile. In contrast, other frequently found genotypes were circulating in the sylvatic and domestic transmission cycles of specific geographical areas. The greatest heterogeneity of T. cruzi stocks was found among sylvatic T. spinolai where at least 4 genotypes were obtained from a sample of 16 T. cruzi stocks.

Animals↗
PubMed1997

Effect of itraconazole on lytic antibodies levels in chronic Chagas disease.

We report the chemotherapeutic effect of itraconazole in chronic chagasic patients. The efficacy of treatment was analyzed by xenodiagnosis (XD), conventional serology (CS) and antibody dependent-complement mediated lysis test (CoML). Twenty chronic chagasic persons from endemic areas of Chile were grouped according to the results of xenodiagnosis (XD) performed before therapy. The follow-up of patients was performed at an average time of 42 months after treatment. No significative statistical differences were observed in the result of ELISA and Indirect Immunofluorescence test performed on serq before and after therapy with itraconazole. In the group of patients with positive XD before therapy, sera from six of them displayed lytic activity against Trypanosoma cruzi. The lytic activity of only one of these sera became negative after therapy. In relation to XD, five of those patients showed a positive tests at least once during the follow-up period. In the group of ten patients with negative XD before therapy, sera from eight of them displayed lytic activity. At the end of the follow-up period seven of them became negative. Nine of the ten patients maintained their original condition with respect to XD. These results suggests that parasitaemia level before therapy condition could be an important parameter to consider in the chemotherapy of chronic Chagas disease.

Adult↗
PubMed1997

Treatment of first tonic-clonic seizure does not improve the prognosis of epilepsy. First Seizure Trial Group (FIRST Group).

It is widely agreed that after two or more seizures patients should be given antiepileptic treatment, but there is still controversy about the treatment of patients after a first unprovoked seizure. In a multicenter, randomized, open trial, patients with a first tonic-clonic seizure were randomized to immediate treatment (carbamazepine, phenytoin, phenobarbital, or sodium valproate) or to treatment only after another seizure. Fifty-two (24%) of the 215 patients randomized to immediate treatment and 85 (42%) of the 204 randomized to delayed treatment experienced seizure recurrence during follow-up. Age, acute treatment of the seizure with benzodiazepines, remote etiologic factors, and EEG abnormalities were significant predictors of relapse. Of the immediately treated patients, 87% had no seizures for a year and 68% had no seizures for 2 years, whereas only slightly fewer initially untreated patients (83% and 60%) achieved these endpoints. Patients treated after the first seizure and those treated after seizure relapse had the same time-dependent probability of achieving 1 and 2 seizure-free years. None of the variables that were prognostic predictors of relapse was significantly associated with the probability of having 1 or 2 years of seizure control. Anticonvulsants in patients presenting a first tonic-clonic seizure reduce the risk of relapse; however, 50% of patients who are not treated will never experience a second seizure. Moreover, the probability of long-term remission is not influenced by treatment of the first seizure.

Adolescent↗
PubMed1996

Karyotype variability in Trypanosoma rangeli.

The molecular karyotypes of several different protozoan parasites show high intra-species variation, including different kinetoplastids such as Trypanosoma brucei, Trypanosoma cruzi and Leishmania ssp. In this study, the molecular karyotype of Trypanosoma rangeli was examined. To evaluate potential intra-species molecular karyotype variations, 16 different samples were studied by pulsed field gel electrophoresis (PFGE) followed by ethidium bromide staining and hybridizations with 6 different probes. The result showed that different T. rangeli populations are highly polymorphic regarding the molecular karyotype, and thus suggests that PFGE analysis can be used for classification of different T. rangeli isolates. In addition, the molecular karyotype of T. rangeli was compared to molecular karyotypes of other kinetoplastids, and was shown to be distinctly different from that of T. cruzi, but shows some similarities with the karyotype described for T. brucei. Among the probes used one was identified as highly polymorphic, and thus informative for studies of different T. rangeli populations, and another was useful for differentiation between T. rangeli and T. cruzi.

Animals↗
PubMed1996

Phenotypic heterogeneity in hereditary neuropathy with liability to pressure palsies associated with chromosome 17p11.2-12 deletion.

Hereditary neuropathy with liability to pressure palsies (HNPP) is commonly associated with a 1.5-megabase deletion on chromosome 17p11.2-12. We analyzed the phenotypic expression of the deletion in 39 HNPP patients from 16 families carrying the deletion. Two-thirds of the individuals had episodes of acute mononeuropathy, often involving nerve territories of the upper limbs or brachial plexus; however, 41% of affected subjects were unaware of their disease, and 25% were almost or totally free of symptoms; one-third complained of chronic symptoms and four older patients had a picture of polyneuropathy. Electrophysiologic abnormalities differed among affected subjects, ranging from conduction abnormalities localized at common entrapment sites to diffuse conduction slowing, usually more evident at entrapment sites; patients from one family had preeminent proximal involvement. The spectrum of phenotypic expression of deletion-associated HNPP appears to be broader than previously thought. The prevalence of the disease is probably underestimated, and the availability of molecular diagnosis should increase disease detection.

Adolescent↗
PubMed1995

Lack of cross-reactivity of lytic antibodies with bloodstream forms of Trypanosoma cruzi zymodemes generated in a mouse experimental model.

Immune sera from mice infected with specific Zymodemes of Trypanosoma cruzi parasites displayed preferential in vitro complement-mediated trypanolytic activity with homologous or genetically related bloodstream trypomastigotes. Culture-derived and metacyclic trypomastigotes were more susceptible to lytic antibodies than bloodstream trypomastigote forms when the same serum panel was tested. Different levels of maximal trypanolytic reaction were observed when several parasites and sera were tested, suggesting that T. cruzi stocks are dissimilar in their efficiency to evade the lytic reaction, probably by capping and shedding mechanisms. A discussion based on the heterogeneity of surface antigens able to elicit the lytic response among different T. cruzi populations is presented.

Animals↗
PubMed1995

Biochemical, immunological, and biological characterization of Trypanosoma cruzi populations of the Andean north of Chile.

Twenty-one Trypanosoma cruzi stocks isolated from Triatoma infestans and humans of the Chilean Andean highlands were studied at the genotypic level by schizodeme and molecular karyotype analyses, which allowed a clear distinction of the parasites from those hosts. A phenotypical characterization was performed by proteolytic activity after electrophoretic fractionation without discrimination among the stocks. Metacyclic trypomastigotes obtained in vitro proved to be infective to Swiss mice and the study of immune response and biological behavior was assessed. Of a total of 21 T. cruzi stocks, only 11 proved to be infective in mice due to difficulties in obtaining metacyclic trypomastigotes with the parasite populations isolated from humans. Western blot analysis revealed a complex immune response even in the first days postinfection with each T. cruzi strain studied. Antigenic recognition by each immune serum is characteristic, although several major and common antigens were detected. Lytic antibodies were studied by the in vitro complement-mediated lytic assay using purified metacyclic trypomastigotes as target cells. All the T. cruzi isolates tested induced lytic antibodies in this experimental model. Parasitemias were moderate and characteristic for each T. cruzi strain. Results are compared with metacyclic forms of the infective and pathogenic Tulahuen strain.

Animals↗
PubMed1995

Purification and characterization of a beta-like DNA polymerase from Trypanosoma cruzi.

A DNA polymerase was purified to near homogeneity from Trypanosoma cruzi epimastigotes. This preparation had a major polypeptide of 50 kDa and a minor band of 45 kDa. SDS-PAGE studies and a novel colorimetric activity gel technique demonstrated that the 50-kDa polypeptide chain is the catalytic subunit of this T. cruzi DNA polymerase. Western blot analysis of different purification stage fractions strongly suggests that this 50-kDa protein is the intact catalytic subunit and does not correspond to a degradation product from a larger one. This T. cruzi DNA polymerase is insensitive to aphidicolin, butylphenyldeoxyguanosine triphosphate, berenil, ethidium bromide and N-ethylmaleimide, but is markedly inhibited by the dideoxythymidine triphosphate analogue. Studies with different DNA templates showed that the DNA polymerase prefers activated DNA as substrate and that it cannot elongate oligoriboadenylate primers. The data presented in this paper are consistent with the hypothesis that this enzyme corresponds to a beta-like DNA polymerase present in the parasitic protozoon T. cruzi.

Animals↗
PubMed1995

Annual variations of in vitro GNRH release by hypothalamic explants in intact and castrated male mink: relations with LH, FSH and testosterone circulating serum levels.

In mink, a short-day breeder, testis growth begins in autumn (November), reaches a maximum in February, before matings occur, and decreases from March to very low volumes during spring and summer. To study the effects of season and testosterone feedback on gonadotrophin and GnRH secretion, the annual variations of LH, FSH, testosterone and GnRH were studied in intact and castrated mink. As portal blood sampling raised serious difficulties, an in vitro static incubation system was used for studying GnRH variations. In intact mink, serum LH concentrations did not vary significantly throughout the year, whereas FSH concentrations increased significantly between September and November then decreased to a minimum in January. Testosterone values rose significantly from November to a maximum from January to March, decreased very rapidly thereafter. Castration in November resulted in a significant increase in LH and FSH concentrations which remained higher than the values measured in intact males throughout the year. In long-term castrated mink, FSH concentrations did not fluctuate during the year, whereas LH concentrations showed an annual variation, with high values in April and August. For the study of in vitro GnRH liberation, medio-basal hypothalamic explants were incubated in Krebs-Ringer phosphate buffer for 3 periods of 15 min, and stimulated with copper complexed equimolarly with histidine (Cu/His, 200 microM) and prostaglandin E2 (PGE2, 10 microM). After Cu/His, the release of GnRH was 1 to 4 fold the basal release; after PGE2, the increase was 4-7 fold the basal release. The basal release of GnRH increased significantly between September and October to reach a maximum in November, decreased significantly in December to a minimum in February then increased progressively from May. The release of GnRH stimulated by Cu/His and PGE2 showed the same seasonal variation as the basal release. Castration 8 days before the sacrifice did not alter the release of GnRH, except in December: the release stimulated by PGE2 was then higher in intact than in castrated mink. Taken together, these results indicate that, with an in vitro static incubation system, it is possible to study the annual variations of GnRH release and to correlate these variations with those of serum gonadotrophin and testosterone concentrations. The synthesis and release of GnRH increased slightly from May, under long days, then more rapidly from September, resulting in an increased secretion of FSH in October, responsible for testis recrudescence. The annual pattern of basal and stimulated GnRH release was similar in intact and castrated mink, suggesting a direct effect of the season on the hypothalamus, rather than a negative feedback effect of the testis; however, testosterone seemed to feedback mainly at the pituitary level.

Animals↗
PubMed1994

Colorimetric detection of DNA polymerase activity after sodium dodecyl sulfate polyacrylamide gel electrophoresis.

A nonradioactive method is developed to detect DNA polymerase activity after sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis containing gapped DNA as template. The technique is based on the use of digoxigenin- or biotin-labeled deoxynucleotides during DNA synthesis, and their detection by means of an anti-digoxigenin antibody-alkaline phosphatase conjugate or by a streptavidin-alkaline phosphatase conjugate. The detection of the DNA polymerase catalytic subunit is achieved after incubation of the gels with colorimetric alkaline phosphatase substrates. The technique is able to detect nanogram amounts of Escherichia coli DNA polymerase I and picogram amounts of its Klenow fragment. The results with other DNA polymerases and E. coli extracts suggest that this colorimetric detection system could be used for the analysis of an extended range of DNA polymerase enzymes. The method presented in this report offers an alternative to the already described radioactive techniques for detection of DNA polymerase activity after SDS-polyacrylamide gel electrophoresis.

Colorimetry↗
PubMed1994

Trypanosoma cruzi epimastigote forms possess a Ca(2+)-calmodulin dependent protein kinase.

Trypanosoma cruzi epimastigote forms showed a tightly bound Ca(2+)-calmodulin-dependent protein kinase activity, which could be partially extracted from membranes and axonemes. The enzyme is constituted by subunits which were autophosphorylated in the absence of exogenous substrates. An antibody against CaM kinase II recognized a Ca(2+)- or Ca(2+)-CaM-dependent conformational epitope in these fractions. The detected bands were of molecular weights similar to the alpha and beta subunits of the corresponding bovine brain enzyme (60 and 50 kDa). Studies using [125I]CaM revealed the presence of a CaM-binding domain. These experiments confirm that the parasite possesses a particulate CaM kinase with characteristics similar to the bovine brain enzyme.

Animals↗
PubMed1994

Agreement in the clinical diagnosis of dementia: evaluation of a case series with mild cognitive impairment.

Interobserver agreement in the clinical diagnosis of dementia among four neurologists was evaluated. The physicians, masked to the original diagnoses, independently reviewed the clinical records of 50 outpatients consulting either the 1st University Neurology Department of Milan or the Neuropsychology Unit of the Medical Center of Veruno (Novara) for suspected cognitive impairment, during a 6-month period. The records contained patients' medical and neurological history, results of neuropsychological testing, laboratory tests, cerebral computed tomography and other investigations. For each patient, the raters had to provide both a diagnosis concerning the presence or absence of dementia and to assign an analytical diagnosis to all the dementia cases. The kappa statistic was used as a measure of interrater reliability. The level of agreement on the primary diagnosis of dementia was moderate (kappa = 0.49); with respect to the nosological diagnoses, the kappa values ranged from 0.16 for depression to 0.80 for multi-infarct dementia.

Aged↗
PubMed1994

[Highly homogeneous Trypanosoma cruzi populations in a low endemic region for Chagas disease: importance in the pathogenesis of Chagas disease in Chile].

Trypanosoma cruzi from 23 chronic and acute cases of Chagas disease were isolated and further characterized. They displayed a remarkable similarity, after typification by schizodeme analysis using restriction endonuclease Eco Ri. All T cruzi isolates belonged to the isoenzymatic Zymodeme 2 Bol. These findings were corroborated analyzing cases from families with demonstrated congenital transmission. The acute cases were newborns or offspring of infected mothers or patients with AIDS. All T cruzi strains isolated in these cases were very similar with almost identical schizodemes. Patients with AIDS had severe clinical manifestations whereas children with congenital infections had a great variety of clinical symptoms. In chronic cases, little clinical differences were observed for the different T cruzi strains. It is concluded that there is a low correlation between the T cruzi strain and the clinical prognosis of Chagas disease, being of greater relevance the host's genetic background and immune response.

Adult↗
PubMed1993

Trypanosoma cruzi: correlation between karyotype variability and isoenzyme classification.

Forty-three Trypanosoma cruzi isolates from Chile and Colombia and three cloned stocks from Bolivia and Brazil were studied at the karyotype level by hybridization with four different parasite gene probes to chromosomes separated by pulsed-field gel electrophoresis. The results showed that classification of parasite isolates based on isoenzyme analysis at 12 or more genetic loci correlated with the classification obtained by molecular karyotype analysis. However, less correlation was found between molecular karyotypes and the zymodemes Z1, Z2Bra, Z2Bol, and Z3 based on analysis at only two genetic loci. All the four probes used in this study allowed differentiation between different T. cruzi stocks but the SAPA and the antigen 13 probes were most informative. Isolates which were unclassified at the isoenzyme level were also studied and in most cases similar hybridization patterns were observed as obtained with one or more isoenzyme-classified isolates. The results demonstrate the potential of using molecular karyotyping as a tool for classification. A few pulsed-field gel electrophoresis hybridization experiments provide the same information as obtained by isoenzyme analysis using a dozen or more enzymes. The clonal theory of T. cruzi propagation is supported by our results since the strong correlation between isoenzyme classification and molecular karyotype is difficult to explain with a sexual mode of replication. No minichromosomes were detected in any of the T. cruzi samples studied. Neither was any strong correlation found between the clinical manifestations of Chagas' disease and the molecular karyotypes of the T. cruzi isolates.

Animals↗
PubMed1993

Nuclear and kinetoplast DNA synthesis in Trypanosoma cruzi, autoradiographical study with DNA polymerase inhibitors.

DNA synthesis in epimastigote forms of Trypanosoma cruzi was studied autoradiographically by incorporation of [3H]thymidine in the nuclear and kinetoplast DNA. Both DNA were heavily labelled. Three eukaryotic DNA polymerase inhibitors (aphidicolin, aracytidine, and dideoxythimidine) were chosen to study the nuclear and kinetoplast DNA synthesis in vivo. Inhibition was mainly observed with the nuclear DNA.

Animals↗