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E Ramírez

Publications and source records attributed to E Ramírez.

At least 55 records · Page 3Linked to original sources
PubMed1994

Red cell acid phosphatase types and GC polymorphisms in Mérida, Oaxaca, León, and Saltillo, Mexico.

Red cell acid phosphatase types and GC polymorphisms were studied in Mérida and Oaxaca, Mexico. GC polymorphisms were also investigated in León and Saltillo. The ACP*A, ACP*B, and ACP*C gene frequencies were 0.215, 0.770, and 0.015 respectively, in Mérida and 0.205, 0.788, and 0.002, respectively, in Oaxaca. In Oaxaca the ACP*R gene had a frequency of 0.005. The results are similar to other Mestizo groups studied in Mexico; it is concluded that the ACP*C and ACP*R genes were introduced by admixture of native Amerindians with whites and blacks, respectively. The GC*1S, GC*1F, and GC*2 gene frequencies were 0.489, 0.289 and 0.222, respectively, in León; 0.500, 0.272, and 0.228, respectively, in Mérida; 0.454, 0.337, and 0.209, respectively, in Oaxaca; and 0.505, 0.356, and 0.139, respectively, in Saltillo. These results are similar to what has been obtained in other Mestizo populations and Indian groups in Mexico, probably because the main ethnic component in both is Amerindian.

Acid Phosphatase↗
PubMed1993

Pathogenic and free-living amoebae isolated from swimming pools and physiotherapy tubs in Mexico.

A protozoological survey was done to isolate free-living amoebae from swimming pools and physiotherapy tubs in Mexico City. Amoebae were isolated by culture in nonnutritive agar medium combined with Escherichia coli. Identification of the isolates was done by morphology using specialized taxonomic keys and by isoelectric focusing of total proteins and isoenzymes in agarose. Pathogenicity of the isolates was determined in 3-week-old mice by intracerebral and intranasal inoculations. Statistical tools were used to determine the existence of significant differences on the incidence and diversity of the isolates in relation to the two types of water bodies analyzed. Water and environmental temperatures, pH, and chloride concentrations were determined at each sampling site. Twenty-nine amoebic strains from eight genera were isolated. Most frequently found were specimens of the genera (Acanthamoeba (with four pathogenic strains), Vahlkampfia, Hartmannella, and Naegleria. Amoebae were isolated more frequently in spring and summer, and could not be recovered from pools with chloride levels of 5.31 mg/ml or more. This survey demonstrates that chloride concentrations commonly used in recreative pools and therapy tubs are not sufficient to eliminate viable cysts of most free-living amoebae. Significantly higher numbers of isolates were retrieved from the pools than from the tubs.

Amebiasis↗
PubMed1993

[Prevalence of HTLV-I antibodies and possible risk factors in Chilean prostitutes].

Aiming to know the prevalence of HTLV-1 infection among high risk groups in Santiago, the antibodies against HTLV-1 were measured in 502 prostitutes coming from north and east Santiago. Antibodies were measured using ELISA and the positive samples were confirmed with an indirect immunofluorescence technique. Four subjects were positive, establishing a HTLV-1 infection prevalence of 0.8%. This number similar to that of other groups of prostitutes from South America and lower than that of prostitutes from Central America, region in which this infection is endemic. The measured prevalence was similar to that of other non promiscuous groups, suggesting that sexual transmission does not play an important role in our population.

Adolescent↗
PubMed1992

Microgravity effects on Drosophila melanogaster development and aging: comparative analysis of the results of the Fly experiment in the Biokosmos 9 biosatellite flight.

The results are presented of the exposure of Drosophila melanogaster to microgravity conditions during a 15-day biosatellite flight, Biokosmos 9, in a joint ESA-URSS project. The experimental containers were loaded before launch with a set of Drosophila melanogaster Oregon R larvae so that imagoes were due to emerge half-way through the flight. A large number of normally developed larvae were recovered from the space-flown containers. These larvae were able to develop into normal adults confirming earlier results that Drosophila melanogaster of a wild-type constitution can develop normally in the absence of gravity. However, microgravity exposure clearly enhances the number of growing embryos laid by the flies and possibly slows down the developmental pace of the microgravity-exposed animals. Due to some problems in the experimental set-up, this slowing down needs to be verified in future experiments. No live adult that had been exposed to microgravity was recovered from the experiment, so that no life span studies could be carried out, but adult males emerged from the recovered embyros showed a slight shortening in life span and a lower performance in other experimental tests of aging. This agrees with the results of previous experiments performed by our groups.

Aging↗
PubMed1992

[Seroepidemiologic study of measles in 2 populations of children under 10 years of age from the metropolitan area].

Measles antibodies were investigated by direct immunofluorescence in 274 samples from infants and 245 samples of children from 1 to 10 years of age. Antibodies were present in 74% of children under 3 months of age, decreasing to 42% at age 11 months. Positive results were obtained in 60% of children from 1 to 4 years of age, decreasing to 47% from 5 to 10 years of age. Overall, infants had 64% positive tests and children 54%. Accordingly, a greater susceptibility to infection by measles is found in infants above 3 months of age and children from 5 to 10 years of age.

Age Factors↗
PubMed1991

[HIV infection. Diagnosis in the national network of laboratories in Chile].

A national network including 114 blood banks and laboratories performs screening for HIV infection on approximately 250,000 blood donors a year. This represents 100% coverage of blood transfusions performed in Chile. Up to December 1990. 4956 samples had been sent to the National Reference Center for AIDS for supplementary studies. HIV infection was confirmed in 1465 (29.6%). A prior study covering the first semester of 1989 showed a 26.9% confirmation rate for HIV infection on 845 serum samples. Technical errors including sample contamination, poor cleaning, decreasing titers of controls and erratic criteria regarding the need for supplementary studies may explain the low confirmation rate reported in this study.

Blood Donors↗
PubMed1990

[Patients with an indeterminate serological diagnosis of HIV-1 infection].

Western blot is the technique most frequently used to determine the presence of HIV-1 antibodies. However, some patients remain with an indeterminate diagnosis for HIV-1 according to the technique. We followed 8 such patients for 2 to 18 months. Immunologic studies included standard ELISA, immunofluorescence and Abbott anti-p24 ELISA. We found selective reactivity for certain viral proteins such as isolated p24, p24 plus p51 or p55, gp41 plus gp 120, p17 plus p24 and p25.

AIDS Serodiagnosis↗
PubMed1990

[Immunity status of 2 Chilean female populations against rubella].

A total of 1248 females were studied to determine immunity against rubella. A higher socio-economic subgroup (n = 789) and a lower one (459) were defined. Inhibition of hemagglutination was used to detect immunity. Positive results were obtained in 95% of females and no differences were detected for both groups. 78% of positive titers fell in the dilution range 1:20 to 1:80.

Adolescent↗
PubMed1988

Sea urchin sperm head plasma membranes: characteristics and egg jelly induced Ca2+ and Na+ uptake.

Sea urchin sperm respond to egg factors with changes in the ionic permeability of their plasma membrane. It has been previously shown that plasma membranes isolated preferentially from sea urchin sperm flagella respond to egg jelly increasing their Ca2+ and Na+ uptake (Darszon et al. (1984) Eur. J. Biochem. 144, 515-522). However, the egg jelly induced acrosome reaction occurs in the sperm head, and there is evidence for an heterogeneous distribution of plasma membrane components within the various regions of this cell. We here report a method for purifying sperm head membranes using positively charged beads according to Jacobson (1977) Biochim. Biophys. Acta 471, 331-335). Under the transmission electron microscope these membranes appeared homogeneous and apparently free of internal membranes. The yield of the preparation was 0.9% of the total protein in the sperm homogenate. The preparation contained less than 5% of the mitochondrial marker cytochrome oxidase, and 10% of the total DNA/mg protein. Surface labeling with 125I indicated a 2.5-3-fold enrichment in specific activity of the head membranes with respect to whole sperm. The SDS band pattern and the lipid composition of this preparation were different from those of isolated flagellar membranes. Phosphatidylcholine was higher in the head membranes, while phosphatidylserine and phosphatidylethanolamine were lower. The head membranes displayed a 1.7-2.3-fold higher Ca2+-ATPase activity and a 2.5-fold lower Na+/K+-ATPase activity, than the flagellar membranes. These results are consistent with a heterogeneous distribution of membrane components along the sea urchin sperm plasma membranes. Isolated head membranes sonicated in the presence of soybean phospholipid liposomes responded to egg jelly with a species-specific increase in Ca2+ and Na+ uptake. As in whole sperm, Ca2+ uptake was inhibited by the Ca2+ channel blocker nisoldipine. A close analog of this compound, [3H]nitrendipine, binds with high affinity to head membranes in a saturable, reversible manner, showing a Kd and Bmax of 31 nM and 5.3 pmol/mg protein, respectively.

Animals↗
PubMed1986

Transthoracic needle biopsy in neoplastic and nonneoplastic pathology: experience in a general hospital.

Transthoracic needle biopsy (TNB) was performed in 344 cases of intrathoracic pathology. In 60 of them, the material obtained was inadequate. In the remaining 284, the possibilities of TNB to identify malignant cells were evaluated. Of them, 202 had neoplastic lesions and 82 had nonneoplastic processes. Among the neoplastic cases, malignant cells were found in 188, (true positive), and in 14 the results were false negative. In the group of nonneoplastic processes, there were 80 without malignant cells (true negative), and two were diagnosed as malignant, (false positive). In these 284 cases with cytologic diagnosis, the global sensitivity was 0.93, and the specificity was 0.97; however, including all cases and the inadequate samples as false negatives, the sensitivity is lower--0.71. TNB required some skill, the use of fine needles, and the collaboration of an expert cytopathologist. TNB is an important method with which to explore intrathoracic pathology.

Biopsy, Needle↗
PubMed1983

Oviposition and development of Drosophila modified by magnetic fields.

Drosophila flies placed in a habitat with two lateral boxes demonstrated sensitivity to magnetic fields: Oviposition decreased by exposure to pulsated (extremely low frequency (ELF) (100 Hz, 1.76 miliTesla (mT) ) and sinusosidal fields (50 Hz, 1 mT), while there was no initial effect of exposure to a static magnetic field (4.5 mT). Drosophila eggs treated for 48 h with the above described fields showed that 1) mortality of eggs was lower in controls than in eggs exposed to all tested magnetic fields; 2) mortality of larvae increased when a permanent magnet was used; 3) mortality of pupae was highest when a permanent magnet was used; and 4) general adult viability was highest in controls (67%) and diminished progressively when eggs were exposed to pulsated (55%), sinusoidal (45%), and static (35%) magnetic fields.

Drosophila melanogaster↗
PubMed1980

Full trisomy 7 and Potter syndrome.

A patient with typical Potter's syndrome and full trisomy 7 is described. All previous reports on chromosome 7 abnormalities, whether monosomic or trisomic, p or q, are reviewed and discussed, establishing two 7q trisomy syndromes: 7q22 ts leads 7q31 and 7q22, q31 leads to 7qter. Some implications of the finding of full trisomy 7 in a case of Potter's syndrome are discussed.

Autopsy↗
PubMed1979

Improved visualization of radiographic cadaver sections using xerotomography.

A new technique using xerotomography for axial images obtained from slices of abdominal cadavers is described. Radiographs were also made in sagittal planes for a complete study of visceral relationships. Xerotomography allows a wider range of visualization in the same plane of anatomical structures, from retroperitoneal fascial planes and vessels to abdominal viscera.

Cadaver↗
PubMed1976

Plasma membrane phosphorylation by endogenous phosphate donors in human blood platelets. Selectivity of the action of dibutyryl cyclic AMP.

Incubation of platelet-rich plasma with 32Pi leads to cellular uptake of the isotope and covalent incorporation into several cell constituents. Plasma membranes isolated from intact labelled platelets, delipidated and solubilized in sodium dodecyl sulfate, show, upon gel electorphoretic analysis, three main peaks of radioactivity: two in the molecular weight range 100 000-30 000 and an additional very slow migrating component strong positive by the peirodic acid-Schiff reaction. Treatment of the cells with dibutyryl cyclic AMP under conditions just sufficient to completely inhibit platelet aggregation leads to an increased isotope incorporation. Electrophoretic analysis of membranes isolated from dibutyryl cyclic AMP-treated cell reveals: (a) no change in the general pattern of distribution of the isotope, (b) no difference in the isotope incorporation to the two components of lower mol. wt. and (c) a marked increase (greater than 100%) in isotope incorporation in the slow migrating material as compared to membranes isolated from control cells. This material can be extracted from platelet plasma membranes after treatment of the membranes for 5 h with Triton X-100, at a detergent-to-protein ratio of 7.5. When the membrane material extracted with Triton X-100 is subjected to gel chromatography in Agarose (Biogel A-15m), the phosphorylated material that corresponds to the slow migrating band in polyacrylanide gel electrophoresis is eluted with or very close to the void volume of the column. Isoelectric focussing of this fraction, shows a single radioactive peak corresponding to an isolectric point of 3.78. The isolated component is pronase-sensitive, contains 52% of carbohydrate and 15% sialic acid. Analysis of the stability of the bound phosphate suggests that about 43% of it is bound as acyl-phosphate. The results reported, obtained through an approach that closely resembles physiological conditions are compatible with the participation of this membrane phosphoglycoprotein in the phenomena of platelet aggregation.

Blood Platelets↗