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Biomedical subjects

L Soto

Publications and source records attributed to L Soto.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effects of endotoxin lipopolysaccharide administration on the somatotropic axis.

The aim of this work was to study the effect of chronic activation of the immune system on the somatotropic axis. Accordingly, the changes in growth hormone (GH) secretion, circulating insulin-like growth factor-I (IGF-I) and IGF binding proteins (IGFBPs) in response to endotoxin lipopolysaccharide (LPS) administration were examined in adult male Wistar rats. Acute LPS injection (2.5, 25 or 250 microg/kg) increased serum corticosterone in a dose-dependent manner and decreased serum levels of insulin and IGF-I, serum GH concentration declined linearly as the LPS dose increased. Western ligand blot showed an increase in the 33 kDa band (corresponding to IGFBP-1 and IGFBP-2) in the rats that received the highest dose of LPS (250 microg/kg). Chronic LPS administration (250 microg/kg daily for 8 days) significantly decreased body weight, serum levels of IGF-I and pituitary GH content, whereas it increased circulating IGFBP-3 (47 kDa band), IGFBP-1 and IGFBP-2 (33 kDa band) and the 24 kDa band (which possibly corresponds to IGFBP-4). Serum concentration of corticosterone and hypothalamic somatostatin content were also increased by chronic LPS treatment. These data suggest that the decrease in GH and IGF-I secretion and the increase in circulating IGFBPs are important mechanisms in body weight loss during chronic inflammation.

Animals↗
PubMed1996

Short and long restraint differentially affect humoral and cellular immune functions.

The aim of this work was to examine the effect of different periods of restraint on the humoral and cellular immune functions in adult male rats. Short restraint stress (2 h over 2 consecutive days) enhanced the primary serum antibody response to sheep red blood cells. The enhancement of this humoral response was dependent on the restraint period, since long restraint stress (6 h over 4 days) failed to modify this response. Short and long restraint decreased both the number of lymphocytes and the T-lymphocyte response to Con A stimulation in the peripheral blood. Neither 2 h over 2 days nor 6 h over 4 days modified the splenic lymphoproliferative response to Con A stimulation, but restraint stress progressively decreased the number of mononuclear splenic cells. Both periods of restraint significantly increased plasma concentration of corticosterone, however plasma prolactin levels were significantly lower after 4 days of restraint but not after short restraint (2 h over 2 days). These results indicate that although some immune functions can be increased after acute or short stress, long stress has an immunosuppressive effect, above all on the cellular immunity which is more susceptible to this effect than the humoral response.

Animals↗
PubMed1996

Do intestinal parasites interfere with the seroepidemiologic surveillance of Schistosoma mansoni infection?

In view of the known cross-reactivity of sera from patients with intestinal parasites to some Schistosoma mansoni antigens, field work was conducted in an area of Venezuela non-endemic for schistosomiasis using the routine immunoenzymatic assay (ELISA) with soluble egg antigen (SEA). False positive reactions represented 15.3% of the total population as determined by SEA-ELISA. SEA-immunoblotting of the false positive sera indicated that protein fractions of 91 and 80 kDa appear to be responsible for cross-reactivity. Sera from hookworm infected individuals produced a higher frequency and intensity of cross-reaction than other sera. SEA-fractions of 105, 54, 46, 42, 32, 25 and 15 kDa were the most specific.

Adolescent↗
PubMed1995

Determination of anions in human and animal tear fluid and blood serum by ion chromatography.

An important factor contributing to the development of ion chromatography (IC) has been the need for repetitive analyses of samples with high ionic contents and samples available in microvolumes. IC was selected for the determination of Cl, NO3, SO(2-)4 and PO(3-)4 anions in tear fluid and serum from ten human volunteers of both sexes, seven young-adult black vultures (Coragyps atratus) and three young-adult chickens (Gallus gallus domesticus). The samples were analysed on a Dionex Model 2000i/SP ion-exchange chromatograph equipped with an anion guard column (Dionex IonPac AG4A), anion separator column (Dionex IonPac AS4A), suppressor column (Dionex AMMS-II) and a conductivity detector. The flow-rte of the mobile phase, 1.7 mM NaHCO3 - 1.8 mM Na2CO3 was set at 2.0 ml/min. The R.S.D. was calculated to be less than 1.5% for all anions. In the human, black vulture and chicken serum samples, the NO3, PO(3-)4 and SO(2-)4 anion contents were higher than in tears; for Cl the reverse was found. No correlation was found amongst the anion concentrations present in the tear fluid and blood serum in all samples (p > 0.05). With no sample treatment, column maintenance was required.

Adolescent↗
PubMed1994

[Detection of anti-gonococcal antibodies using a dot immunobinding assay in a high risk female population].

The bacteriological diagnosis of gonorrhea in women has a low efficiency. A dot immunobinding assay, using whole piliated Neisseria gonorrhoeae cells, was used to detect antigonococcal antibodies in 300 prostitutes in whom a parallel Thayer-Martin culture of endocervical secretion was performed. Twenty sera from men with bacteriologically confirmed gonorrhoea were used as positive controls and 20 sera from children without history of gonococcal infections, as negative controls. Antibodies were detected in 49.7% of women and culture was positive in only one. All men with gonorrhea has positive titers and all sera from children were negative, except one that had a cross-reaction. Test sensitivity in the female population was 1 and specificity 0.5. There were no false negative reactions. Although the test detected antibodies in high risk women, there were cross-reactions. Therefore, the technique should be improved, using a more specific antigen.

Antibodies, Bacterial↗
PubMed1993

[Frequency of sickle-cell anemia in the population of "Cuatro Bocas," Parroquia Ricaurte, Mara municipality, Zulia state, Venezuela].

Isla de Toas is an island on the north of the Maracaibo Lake, it is known in the scientific community, for the high frequency of sickle cell disease, in a population with caucasoid phenotype. The purpose of the present work was to determine the frequency of sickle cell anemia in the population of Cuatro Bocas, situated 35 km from the southwest of Isla de Toas. The town is the center of confluence of a rural population constituted mainly of farmers. The sample consisted of 870 persons of both sexes, aged from 8 months to 66 years. The presence of the sickling phenomenon was determined in all the individuals, and hemoglobin electrophoresis in agarose was performed in all the positive samples. The following results were obtained: fifty-six cases (6.4%), showed drepanocytic changes, and forty-six of them were haemoglobin A/S, 8 were S/S and 2 were S/C. The higher frequency of hemoglobin S was in adolescents and adults. The family backgrounds suggest an insular origin of the sickle cell gene. About 75% of the affected population was ignorant of this condition. The hemoglobin values were lower in the individuals with the sickle cell disease (p < 0.05), than in the normal persons. Iron deficiency in adolescents was suspected because or their low hemoglobin values. The results indicate that the sickle cell gen is expanding to the nearest communities of the Mara county. It is important to consider that the findings of the present work should serve as an alert to the Public Health authorities, and that education of the population is important in order to prevent the spreading of the disease.

Adolescent↗
PubMed1993

[Diagnosis of bacterial meningitis by latex agglutination tests].

Fifty samples of cerebrospinal fluid (CSF) from patients with acute bacterial meningitis were studied with direct gram examination, culture and latex agglutination. Twenty one of these samples had previous antimicrobial treatment. In 42 patients, blood cultures were also made. Thirty control CSF samples were also studied. The diagnostic yield of CSF culture was 72%, of direct gram examination 74% and latex agglutination 80%. All the techniques as a whole has a diagnostic yield of 92%. In the 21 CSF samples with previous antimicrobial treatment, culture was positive in 47.6% and latex agglutination in 85.7%. All control CSF samples were negative. It is concluded that the diagnostic yield of latex agglutination test in patients with previous antimicrobial treatment is significantly better than culture.

Acute Disease↗
PubMed1993

[Three years of acute bacterial meningitis in the pediatric service at the Temuco Regional Hospital].

The aim of this work was to study the clinical, epidemiological and laboratory features of 90 children, hospitalized between 1988 and 1991 with the diagnosis of acute bacterial meningitis in a region with a high proportion of aboriginal population. Twenty six percent of studied patients were of mapuche origin. The causative organism was identified in 82% of cases (H influenzae in 38% of cases, S pneumoniae in 29% and N meningitidis in 10%). H influenzae was resistant to ampicillin in 16% of cases and resistant to chloramphenicol in 4%. This agent was identified in 52% of patients of mapuche origin compared with 33% of non mapuche patients. Seventy three percent of children were less than 2 years old. Thirty seven percent of children had complications during hospitalization, 12 children died (13.3%) and 38% of children had neurological sequelae at the moment of discharge.

Acute Disease↗
PubMed1992

Left-sided endocarditis in parenteral drug abusers: recent experience at a large community hospital.

Endocarditis in IV drug abusers involves the right side of the heart with much higher incidence than in the general population, being limited to the left in 30% to 40% of cases. The infecting organism is Staphylococcus aureus approximately 50% of the time, followed by Streptococcus (all groups), which accounts for 15% of all cases. In a retrospective study of infective endocarditis in IV drug abusers treated at Charity Hospital over a 5-year period, 67 patients had vegetations documented by two-dimensional echocardiogram. Left-sided involvement was present in 38 (57%) of these patients, a higher prevalence than reported in the literature in such populations. Right-sided involvement was limited to only 27 (40%). A total of 55 patients had positive blood cultures, most of which yielded Staphylococcus aureus (32 [58%]), with the next largest group being Streptococcus species (14 [25%]). This distribution of isolates was consistent with that found in the literature. From these data we conclude that the prevalence of left ventricular endocarditis in our population is higher than expected. With the known increase in morbidity and mortality of left-sided endocarditis as compared to right, it is imperative that careful consideration be given this entity often encountered in IV drug abusers.

Adolescent↗
PubMed1990

[Immunofluorescence in the diagnosis of acute bacterial meningitis].

We evaluated immunofluorescence techniques to investigate the presence of S pneumoniae, N meningitidis, H influenzae types a and b and L monocytogenes in 85 samples of CSF fluid: 60 were taken from patients suffering meningitis and 25 from a control group. Results were compared to conventional bacteriologic methods. There were no false positive results in the control group. In patients with meningitis, 28 were positive by both methods. Nine additional patients were positive only to immunofluorescence which allowed identification of S pneumoniae in 6, N meningitidis in 2 and H influenzae in 1. 37 samples were positive by immunofluorescence and 28 of them were positive to conventional bacteriology. There was only 1 case of Group B streptococcus identified by bacteriology which was not diagnosed by immunofluorescence. Thus, immunofluorescence increases the ability to make a bacteriologic diagnosis in patients with meningitis.

Acute Disease↗
PubMed1976

[Pharmacological reactivity in cricetus aureus uterus (author's transl)].

The motility of the isolated Cricetus auratus uterus was studied and compared to that of other species. Oxitocyn, epinephrine, norepinephrine, histamine, 5-hydroxy-tryptamine and acetylcholine were used as spasmogen agents. There was not contractil response with epinephrine or nor-epinephrine. Histamine reduced basal tonus. There was contraction with acetylcholine, oxytocin and 5-hydroxy-tryptamine. Cricetus auratus uterus appeared more sensitive when the contraction was registered by the isometric method. No taquifilaxy was produced by 5-hydroxy-tryptamine, as opposed to such effect in rat uterus. The Cricetus auratus uterus has, therefore, shown similar reactivity to that of rat, but different from rabbit and guinea-pig.

Acetylcholine↗