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Biomedical subjects

A Solari

Publications and source records attributed to A Solari.

At least 73 records · Page 4Linked to original sources
PubMed1993

Proliferation of follicular cells and the effect of FSH on the onset of follicular growth in the ovary of 30-day old rabbits studied by continuous labelling with 3H-thymidine.

The ovary of the 30-d-old rabbit contains only small follicles with, at most, 3 or 4 layers of cells. We have estimated the labelling index of the follicular cells only from follicles having at least one labelled cell and using a zero truncated binomial distribution. The labelling index of the follicular cells of such follicles was weak and enlarged with the number of cells. It never exceeded 20%. Repeated injections of tritiated thymidine up to 8 times entailed a significant increase of the labelling index even for the smallest follicles. The labelling index of follicles was significantly increased 30 h after 1 injection of FSH (2 mg P-FSH). These results confirmed that the fraction of follicular cells that proliferate was low in the young rabbit ovary and the doubling time of the cells was large and that at this age, FSH increased the proliferation of cells.

Animals↗
PubMed1993

Successful treatment of Trypanosoma cruzi encephalitis in a patient with hemophilia and AIDS.

Although the frequency of infection with the human immunodeficiency virus (HIV) is increasing dramatically in areas where Trypanosoma cruzi is endemic, trypanosomiasis has been rarely reported in persons with HIV infection or AIDS. Persons with hemophilia who receive multiple blood product transfusions from blood banks with little or no screening for infectious agents are at particularly high risk for infections with both HIV and T. cruzi. We describe the case of a person with hemophilia who was infected by blood transfusion with HIV and T. cruzi and in whom a multifocal, necrotic trypanosomal encephalitis was demonstrated by brain biopsy and electron microscopy. Treatment with benznidazole followed by that with itraconazole and fluconazole was associated with significant clinical and radiographic improvement.

AIDS-Related Opportunistic Infections↗
PubMed1993

Accuracy of self-assessment of the minimal record of disability in patients with multiple sclerosis.

We tested the validity of a self-administered version of the minimal record of disability (MRD) for multiple sclerosis (MS) by measuring the agreement level between patients' self-assessment and neurologists' independent ratings. 96 MS patients and 4 neurologists took part in the experiment; the agreement level was measured in terms of the intraclass correlation coefficient (ICC). On the Kurtzke functional system (FS) the ICC ranged from 0.26 in the sensory to 0.69 in the pyramidal function; a high concordance (ICC = 0.84) was found on the expanded disability status scale (EDSS). The ICC values were above 0.70 for most of the incapacity status scale (ISS) and environmental status scale (ESS) items. A modified, self-administered version of the MRD may represent a reliable instrument for obtaining a comprehensive profile of patients' abilities.

Adolescent↗
PubMed1993

Characterization of Trypanosoma cruzi populations by several molecular markers supports a clonal mode of reproduction.

Chilean T. cruzi populations from different endemic areas and transmission cycles were characterized at several biochemical levels, to mention: hybridization with kinetoplast DNA probes, molecular karyotype, isoenzyme studies and kinetoplast DNA restriction fragment length polymorphism. Furthermore, an immunological approach with immune sera from Balb/c infected mice with different T. cruzi populations was used to differentiate among parasite types by the in vitro complement-mediated lysis assay. Parasite grouping by the above described methods allows to classify T. cruzi populations on a very defined number, suggesting that they have a clonal structure.

Animals↗
PubMed1992

Characterization of Chilean, Bolivian, and Argentinian Trypanosoma cruzi populations by restriction endonuclease and isoenzyme analysis.

Ninety-one Chilean, 15 Bolivian, and 9 Argentinian Trypanosoma cruzi stocks, isolated from various hosts and vectors, were characterized by schizodeme analysis with EcoRI and MspI endonucleases. The three major similar pattern groups that emerged from this sample correlated with results of isoenzyme analysis. This result confirms previous work and supports the hypothesis of the clonal structure of natural populations of T. cruzi, fully defined at the level of isoenzyme analysis, quantitative kinetoplast DNA restriction fragment length polymorphism, and kinetoplast DNA hybridization analysis. In Chile, sylvatic and domestic cycles of T. cruzi transmission appear to be mainly independent: genetically different families of natural clones are specific to these cycles. Nevertheless, the possibility of overlap remains unclear. Results described here indicate that natural clones inhabiting Chilean regions appear genetically related to the natural clones identified in neighboring countries. In Chile the more frequently sampled parasite types are natural clone 39 and a genetically closely related clone NP13. In this work an evaluation of T. cruzi natural clone mixtures in T. cruzi stocks from Chile was performed for the first time by schizodeme analysis before and after serial transfer in mouse maintenance. The results indicate that six of nine stocks are composed of two or more natural clones. This observation raises the relevant question of whether specific T. cruzi natural clones generate different clinical features of Chagas' disease.

Animals↗
PubMed1992

Two DNA polymerases from Trypanosoma cruzi: biochemical characterization and effects of inhibitors.

1. Two DNA polymerases have been partially purified from Trypanosoma cruzi epimastigotes by DEAE-cellulose, phosphocellulose, and DNA agarose chromatography. 2. Both enzyme activities were characterized by several biochemical criteria. 3. They showed different sensitivity to KCl and displayed characteristic Mg2+ and Mn2+ requirements, although they exhibited almost identical primer-template utilization. 4. The preferred substrates were poly dC-oligo dG, activated calf thymus DNA, and poly dT-oligo rA. 5. Both enzyme fractions are not inhibited by aphidicolin while N-ethylmaleimide and phosphonacetic acid inhibited them to different extents. 6. ButylphenyldGTP strongly inhibited T. cruzi enzyme fraction I while it had no effect on enzyme fraction III. 7. This dGTP analog also inhibited the poly dT-directed polymerization of dAMP as described for other mammalian DNA polymerases. Kinetic studies indicated that butylphenyldGTP inhibited enzyme fraction I in a non-competitive fashion.

Animals↗
PubMed1992

Evidence for a gonadal nonsteroidal factor that specifically inhibits release of luteinizing hormone in ewes.

Bilaterally ovariectomized ewes were used to investigate the effect of systemic administration (i.v.) of charcoal-treated aqueous luteal extracts from ovine corpora lutea on plasma concentrations of pituitary gonadotrophins. Jugular blood samples were taken every 15 min at least 5 h before (control period) and 5 h after (treatment period) injection. In Expt 1, the administration of luteal extract from corpora lutea of days 70-76 of pregnancy, but not of the extract prepared from muscular tissue, resulted in a significant decrease of mean concentrations of luteinizing hormone (LH) (P < 0.02) and frequency of LH pulses (P < 0.01). Plasma follicle-stimulating hormone (FSH) concentrations were not affected by injections of either extract. These findings provide the first demonstration of the presence of a nonsteroidal factor in the corpus luteum of midpregnancy that selectively suppresses the secretion of LH. In Expt 2, mean concentrations of LH and FSH and frequency of LH pulses were unaffected by injections of luteal extracts from ovine corpora lutea of days 10-12 of the oestrous cycle or day 15 of pregnancy. These data suggest that some factor(s), probably from the fetoplacental endocrine unit, is required to ensure the production of a significant quantity of the luteal LH-inhibiting factor after day 15 of pregnancy. In Expt 3, treatment of luteal extract from corpora lutea of day 70 of pregnancy with proteolytic enzymes destroyed the LH-inhibiting activity, suggesting the proteic nature of the luteal LH-inhibiting factor. In Expt 4, plasma concentrations of LH were not affected by injection of charcoal-treated extract prepared from fetal cotyledonary tissue of days 110-120 of pregnancy suggesting that the LH-inhibiting factor exclusively originates from the corpus luteum during pregnancy. These experiments provide the first direct evidence for the existence of a potent nonsteroidal factor of luteal origin that specifically inhibits pulsatile secretion of LH, without influencing FSH release in female animals. We propose the term LH-release-inhibiting factor (LH-RIF) to describe this activity.

Algorithms↗
PubMed1991

Evidence of absence of Trypanosoma cruzi kinetoplast DNA methylation by restriction endonuclease analysis.

Eight kinetoplast DNA samples from very different T. cruzi zymodemes were digested with the isoschizomer group of enzymes (MspI-HpaII) and (MboI-Sau 3AI), able to detect DNA methylation on cytidine and adenine for the CCGG and GATC sequences, respectively. Restriction digestion analysis of each kDNA with both isoschizomer groups of enzymes did not display a different profile suggesting that maxicircles and minicircles on this trypanosomatid are not methylated.

Animals↗
PubMed1991

General procedure to construct highly specific kDNA probes for clones of Trypanosoma cruzi for sensitive detection by polymerase chain reaction.

Our strategy of probes designing for major clones of Trypanosoma cruzi was performed taking into account the: (i) clear identification of the major clones under multilocus study; (ii) hypothesis of a parallel evolution between the extranuclear and nuclear markers; (iii) structure of kDNA which allowed to amplify high variable regions of the minicircle (HVRm) by PCR. The large production of HVRm was very useful to test their ability to be used as probes for detection of DNA from a diversified genetic panel of T. cruzi. Our success in designing such probes has important implications on: the enhancement of 2 evolutive hypothesis about the clonal structure of T. cruzi and the parallel evolution of their extranuclear and nuclear genetics markers; direct diagnosis in patients and vectors. Studies on bio-clinical significance of major clones are discussed. This procedure could be used as a general strategy to generate DNA probes for Kinetoplastida.

Animals↗
PubMed1990

Biological characterization of Trypanosoma cruzi zymodemes: in vitro differentiation of epimastigotes and infectivity of culture metacyclic trypomastigotes to mice.

Thirty-one Trypanosoma cruzi isolates from Chile, Peru, and Bolivia were studied in their capacity to differentiate in vitro from epimastigotes to metacyclic trypomastigotes on TAU-3AAG medium. Zymodeme 1 parasites displayed the best level of differentiation, which ranges from 60 to 90% depending on the isolate. Zymodeme 2 parasites exhibited highly heterogenous differentiation rates. This differentiation method permits the obtention of large amounts of metacyclic trypomastigotes from zymodeme 1 parasites. Metacyclic trypomastigotes obtained in vitro were infective to nude Balb/c hybrid mice. Zymodeme 1 parasites produced high parasitemias in this murine model; in contrast, zymodeme 2 parasites displayed lower parasitemias. Of a total of 27 T. cruzi isolates, 20 proved to be infective to mice, 12 gave enough parasites for further studies, and 8 of these were used for biological characterization. Results are compared with the infective clone Dm28 and Tulahuén strains maintained since 1954 in mice.

Animals↗
PubMed1990

[Chagas cardiopathy in the first region of Chile. Clinical, epidemiologic, and parasitologic study].

705 inhabitants of rural towns in northern Chile were surveyed to study chagasic infection and cardiac involvement. Clinical evaluation, electrocardiogram, indirect hemagglutination test and xenodiagnosis for reactors were employed. Culture of positive xenodiagnosis was done to identify different zymodemes and schizodemes of T cruzi, T spinolai was not found in this area implying the absence of a wild cycle. Triotomines were not found over 3000 m high. Four cases of Z2b T cruzi strains were found. Simultaneous infection by Z1 and Z2b strains was found in the same bug obtained from houses. Overall human infection rate was 10%, and 69% of them showed altered electrocardiograms. Therefore, a lower infection rate but greater evidence of cardiac involvement is found in northern Chile compared to other areas in the country.

Adolescent↗
PubMed1989

Interobserver agreement in the diagnosis of multiple sclerosis.

Interobserver agreement in the clinical diagnosis of multiple sclerosis (MS) among six neurologists was evaluated. Three of them participated in a study of the clinical diagnosis of MS, the Italian Multicenter Study (IMS). The raters examined the clinical forms of MS of 50 patients randomly selected from among 430 patients recruited from the IMS. For each patient, neurologists were asked to make a diagnosis according to the McDonald-Halliday classification system of MS. The overall agreement on the diagnosis (MS present or absent) was fair, with no difference noted between the two groups of raters. Considering the six diagnostic levels instead, the reliability was higher for the neurologists participating in the IMS program. These neurologists agreed particularly on the Clinically Definite and Progressive Possible classifications. Complete disagreement was observed for the Early Probable or Latent and Progressive Probable classifications. Because of the different level of agreement on diagnosis, we suggest separate consideration of Clinically Definite and Progressive Probable MS cases in clinical trials and epidemiologic studies of this disease.

Adult↗
PubMed1989

In vitro culture of bovine egg fertilized either in vivo or in vitro.

Three-quarters of in vivo and one-third of in vitro fertilized bovine eggs reached blastocyst stage when cultured on tubal cell monolayers (TCM), but no hatching occurred in B2 medium supplemented with estrous cow serum. When after 3 days of culture on TCM, morulae were transferred on endometrial cell monolayers (UCM), the same proportion of blastocysts was obtained and one-third of them hatched. Histological studies of hatched blastocysts showed that the number of inner cells was significantly lower than in hatched blastocysts recovered in vivo 8-8.5 days after ovulation. Moreover, the number of pycnotic cells was higher than normal, although mitosis were present. On the contrary, there was no difference in either the number or the appearance of trophoblastic cells between blastocysts obtained in vitro and in vivo. The addition of transforming growth factor (TGF-beta) to either TCM or UCM co-cultures at the very beginning of blastocyst formation specifically stimulated growth of the inner cell mass (ICM). The number of cells at hatching was about double (120) and significantly higher than that found in 8-8.5-day blastocysts in vivo. Moreover, hatching percentages were similar to the controls, even when eggs were cultured for 8 days only on TCM. However the proportion of pycnotic cells remained higher than normal, although many mitotic cells were unevenly distributed in ICM) In vivo during hatching, there were always pycnotic cells in ICM, but their number was limited and approximately similar to the number of mitosis. The uterine factors which control both mitosis and pycnosis in ICM remain to be discovered.

Animals↗
PubMed1989

Evidence that the corpus luteum of pregnancy contributes to the control of tonic secretion of LH in the ewe.

Concentrations of LH and FSH were measured in blood samples collected from the jugular vein at 20-min intervals for 7 h (09:00-16:00 h) on Days 60, 80, 100 and 120 of pregnancy in 5 intact ewes and 5 from which the CL had been excised on Day 70. In the 5 intact ewes, plasma LH concentrations remained low and unchanged between Days 60 and 120. During this period, pulsatile release of LH occurred irregularly and infrequently. Removal of the CL resulted in an increase in the basal values of LH and in the frequency and amplitude of LH pulses. Concentrations of FSH were relatively constant in all stages of pregnancy examined and were similar in both groups of ewes. These results show that (1) LH concentrations are low during the second half of pregnancy; and (2) LH, but not FSH, increases after CL excision, presumably by removing some luteal factor inhibitor of LH secretion.

Animals↗
PubMed1988

An image analysis morphometric method for the study of myelinated nerve fibers from mouse trigeminal root.

For the morphometric light microscopic study of myelinated fibers in mouse trigeminal root, it was necessary to write: (1) an entirely automatic analysis program for the myelinated axons inside the myelin sheath, based on the detection of the myelin sheaths, and (2) an interactive analysis program for the myelinated fibers outside the myelin sheath, due to the high density of compactness of the myelinated fibers based on an indirect fiber individualization by reconstructing them from their axons. In the latter, a semiautomatic correction method (drawing the profile contours with a light pen) allowed compensation for the failures of the automatic method, except for the smallest fibers, which represented 8% of the total. Using these programs, 95% of the axons could be measured and 92% of the myelinated fibers whose axons were analyzed could be measured. The area-equivalent diameter was independent of the detection method; it is a correct-size measurement parameter for axons and fibers that is unrelated to their shape. The projected diameter, an estimation of the perimeter obtained by measurement of the profile projections, depended upon the detection method because the profile contour was influenced by the detection method; it thus takes into account the profile shape. For myelinated fibers, whose analysis program used two detection methods (automatic and semiautomatic), there was an average difference of 16% between the projected diameters obtained with these two methods, whereas the equivalent diameter value was the same. The fiber circularity factor could not be precisely estimated because of the detection error; the axon circularity factor was more reliable since the axon detection was completely automatic.

Animals↗
PubMed1987

Schizodeme analyses of Trypanosoma cruzi zymodemes from Chile.

Kinetoplast DNA was isolated from Chilean Trypanosoma cruzi populations and digested with the restriction endonucleases EcoRI, HinfI, HpaII, MspI, and HaeIII. Three major schizodeme groups were discriminated. There was a correlation between the Chilean schizodeme groups (S1, S2, or S3) and the zymodemes known to occur in Chile (Z1, Brazilian Z2 and Bolivian Z2, respectively), although heterogeneity was seen within the schizodeme groups S2 and S3. Standard Brazilian and Bolivian T. cruzi clones (X10 clone 1, Esmeraldo clone 3, SC43 clone 1, and CAN III clone 1) and laboratory strains (Tulahuen and Y) were included in the schizodeme comparisons. SC43 clone 1 had obvious affinities with S3 and X10 clone 1 shared some features with S1 but the other reference stocks could not be definitely assigned to S1, S2, or S3. Fragment patterns and densitometric traces following digestion with HpaII or MspI suggested that kDNA sequences were not methylated.

Animals↗
PubMed1987

Trypanosoma cruzi isolates from Argentina and Chile grouped with the aid of DNA probes.

Fifty-two isolates and several clones from Trypanosoma cruzi, the agent of Chagas' disease, were analyzed using cloned minicircles or total kinetoplast DNA as probes. Isolates were obtained from triatomines, guinea pigs and infected humans in the Central and Northern regions of Argentina and the North of Chile. 35% of all the randomly selected isolates could be identified with one cloned minicircle probe. This widely distributed T. cruzi group was detected on both sides of the Andes mountain range (Argentina and Chile) in Triatoma infestans as well as in human infections. Most of the other isolates could be grouped with four kinetoplast DNAs as probes, but their geographical distribution seems to be restricted as compared with the one mentioned above. These results confirm the heterogeneity of T. cruzi subspecies in nature and the usefulness of DNA probes to group them.

Animals↗