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Biomedical subjects

P Uribe

Publications and source records attributed to P Uribe.

At least 19 recordsLinked to original sources
PubMed2003

[New techniques in the study of asthma].

Asthma is a chronic inflammatory disease of the airways that is functionally characterized by variability of lung function and bronchial hyper-responsiveness. Its diagnosis and management is commonly hampered by the lack of objective parameters. This article reviews additional techniques for evaluating both, lung function (bronchial challenge with adenosin-monophosphate, lung resistance measurement by either the impulse oscillometry system or whole body pletismography) and bronchial immuno-inflammatory response (induced sputum, condensates of exhaled air, monitoring of nitric oxide in exhaled air), as well as our experience with them.

Airway Resistance↗
PubMed2000

Comparative studies of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine.

OBJECTIVES: To compare the efficacy and safety of two-times-daily versus three-times-daily indinavir in combination with zidovudine and lamivudine. DESIGN: Two multicenter, open-label, randomized 24-week studies. METHODS: Adults HIV-1 infection, HIV-1 RNA greater than 10000 copies/ml, and no prior lamivudine or protease inhibitor therapy were eligible. In a pilot study (Study A), patients received indinavir at 800 mg every 8 h, 1000 mg every 12 h, or 1200 mg every 12 h. In a subsequent study (Study B), patients received indinavir at 800 mg every 8 h or 1200 mg every 12 h. All subjects received zidovudine (300 mg) and lamivudine (150 mg) every 12 h. An intent-to-treat analysis was used. RESULTS: In Study A, which enrolled 88 patients, neither HIV-1 RNA nor CD4 cell responses differed significantly between treatment groups at 24 weeks when corrected for multiple comparisons. Study B enrolled 433 patients, but was prematurely discontinued when interim analysis suggested greater efficacy of three-times-daily indinavir. Of the first 87 patients reaching week 24, HIV-1 RNA was less than 400 copies/ml in 91% receiving three-times-daily versus 64% receiving two-times-daily indinavir (P < 0.01). CONCLUSION: Three-times-daily indinavir appears more efficacious than two-times-daily dosing when administered with zidovudine and lamivudine. Two-times-daily indinavir dosing should only be considered in situations characterized by favorable pharmacokinetic drug-drug interactions.

Adult↗
PubMed2000

Functional cross talk after activation of P2 and P1 receptors in oviductal ciliated cells.

The presence of ATP and adenosine receptors and their role in controlling ciliary activity in oviductal ciliated cells was studied by measuring the ciliary beat frequency (CBF) in oviductal tissue cultures. ATP, adenosine, and related compounds increased the CBF in a dose-dependent manner. We established that P2 receptors of subtype 2Y(2) and P1 receptors of subtype A(2a) mediated the responses to ATP and adenosine, respectively. We found evidence to suggest that stimulation of ciliary activity by ATP requires D-myo-inositol 1,4, 5-trisphosphate [Ins(1,4,5)P(3)] metabolism, intracellular Ca(2+) mobilization, and protein kinase C activation. On the other hand, the adenosine effect is mediated by activation of a G(s) protein-dependent pathway that enhances cAMP intracellular levels. To study the interaction between P2 and P1 receptors, cells were stimulated simultaneously with both agonists. We observed a synergistic increase of the CBF even at agonist concentrations (100 nM) that did not produce a significant response when added separately to the culture. Furthermore, a blocker of the cAMP pathway produced a reduction of the ATP response, whereas a blocker of the Ins(1,4,5)P(3) pathway also produced an inhibition of the adenosine response. Our evidence demonstrates that both ATP and adenosine receptors are present in a single ciliated cell and that a mechanism of cross talk could operate in the transduction pathways to control ciliary activity.

Adenosine↗
PubMed1995

[Progression of viral infection in twins born from a mother infected with human immunodeficiency virus].

We studied the evolution of HIV-1 infection and immune response during six years in two twins born from an infected mother. The children had a continuous progression of the infection, proved by CD4+ cell count, serum anti-HIV antibodies, cultivable virus and proviral load. Now, both children are on antiviral treatment. The analysis of serum antibodies showed a different immune response in both children. One of them developed higher levels of antibodies directed against viral proteins and synthetic peptides derived from their aminoacid sequence. In this child, the amount of cultivable virus increased less than in his twin. Nucleotide sequencing of a part of viral genoma, showed that the virus belonged to the B subtype, prevalent in America and Europe. The observed differences in viral sequences suggest a different selective pressure in both twins. This phenomenon could be related to the observed differences in immune response.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Sexual behavior and status for human immunodeficiency virus type 1 among homosexual and bisexual males in Mexico City.

The authors examined sexual behaviors, the seroprevalence of human immunodeficiency virus type 1 (HIV-1), and condom use among 2,314 homosexual and bisexual men tested during 1988-1989 at the AIDS (acquired immunodeficiency syndrome) National Center in Mexico City. Bisexuals constituted 24% of the sample; the seroprevalence rate was lower for bisexuals than homosexuals (21 vs. 34%). In logistic regressions, HIV-1 seropositivity was independently related to age, education, pattern of insertive/receptive behavior in anal sex, lifetime number of male sex partners, having sex with someone with AIDS, homosexual versus bisexual behavior, and a history of condyloma. The same logistic regressions were found to fit bisexuals and homosexuals. The rate of HIV-1 was reduced in individuals who indicated always requiring their partners to use a condom when practicing receptive anal sex (1% of the total). The most common practice for both homosexuals and bisexuals was "mixed" behavior (i.e., both insertive and receptive anal sex); this was also the practice with the highest risk. Bisexuals practiced both vaginal and anal sex with women and reported little condom use. The substantial seroprevalence among bisexuals, their frequent sexual contact with women, and their low rate of condom use imply a continuing role as a bridge of infection to females. Whether this risk will lead to a sustained heterosexual epidemic remains to be determined.

Adolescent↗
PubMed1992

Reactivity patterns and infection status of serum samples with indeterminate Western immunoblot tests for antibody to human immunodeficiency virus type 1.

Serum samples with indeterminate Western blot (WB) tests from 61 individuals whose sera were positive by enzyme-linked immunosorbent assay (ELISA) were studied in order to characterize their putative reactions with the human immunodeficiency virus (HIV) proteins and to resolve the HIV infection status of these individuals. The reaction observed by WB could not be confirmed either by radioimmunoprecipitation assay and subsequent electrophoresis (RIPA) or by use of LiaTek (Organon Teknika, Turnbout, The Netherlands) in 28% of the samples. Of the 86 samples that were indeterminate by WB, 66 reacted with p24 by WB; this reaction was confirmed by RIPA in only 21 (32%) and by LiaTek in 49 (74%) of the 66 samples. On the other hand, none of the indeterminate samples that reacted with HIV envelope proteins by WB did so by LiaTek, while 50% precipitated at least some of these proteins in the RIPA. The sensitivities of the three methods for detecting the antibody reaction with the different HIV proteins, which were studied with serial dilutions of positive serum samples, were similar. Thus, a lower sensitivity of RIPA or LiaTek does not seem to be the cause for the lack of reaction of the WB-indeterminate samples by these two methods. Sequential samples from individuals whose serum samples reacted by the three methods gave reproducible results, but all showed low antibody titers. Peripheral blood mononuclear cells obtained from three of the four individuals with sequential samples that reacted with HIV env proteins by WB and RIPA were negative for HIV provirus DNA after amplification by the polymerase chain reaction.

Blotting, Western↗
PubMed1992

[Hospital personnel who are nasal carriers of methicillin-resistant Staphylococcus aureus. Usefulness of treatment with mupirocin].

BACKGROUND: The evaluation of health care workers role in methicillin-resistant Staphylococcus aureus outbreaks and the efficacy of mupirocin as a topical agent for nasal carriers. METHOD: Microbiologic study of nasal microflora of 1547 health care workers from the San Carlos University Hospital and 108 health care workers from related hospitals while an outbreak of methicillin-resistant Staphylococcus aureus nosocomial infections is in progress at San Carlos University Hospital. Assessment of the efficacy of mupirocin nasal ointment for nasal carriers using microbiologic controls of nasal and pharyngeal swabs at the end of treatment and two weeks after. RESULTS: In San Carlos University Hospital a total of 53 health care workers with nasal carriage of methicillin-resistant Staphylococcus aureus were found. That figure represents a 3.4% of all health care workers studied and also a 15.4% of methicillin-resistance among all S. aureus isolated. Among health care workers from related hospitals, only one nasal carrier was found. Forty-seven of all 53 methicillin-resistant Staphylococcus aureus isolated from San Carlos University Hospital health care workers and the strain isolated from the related hospitals health care worker were similar to the epidemic strain responsible for the outbreak. Mupirocin, as nasal ointment, was useful in eliminating nasal colonization in all cases. CONCLUSIONS: When a nosocomial outbreak of methicillin-resistant Staphylococcus aureus infections is detected, health care workers are one of the most important reservoirs. Topical treatment with mupirocin (nasal ointment) is useful for eliminating the nasal carrier status.

Administration, Intranasal↗
PubMed1990

Immunoprecipitation of human immunodeficiency virus type 2 glycoproteins by sera positive for human immunodeficiency virus type 1.

Analysis by radioimmunoprecipitation of serum samples from 27 different human immunodeficiency virus type 1 (HIV-1)-infected individuals residing in Chile showed that the sera of 26% of these individuals also react with glycoprotein gp125 of HIV type 2 (HIV-2). This cross-reaction seems to reflect a qualitative difference among infected individuals, because the titer of antibodies against gp120 of HIV-1 in the cross-reacting samples did not differ significantly from that in the non-cross-reacting samples. Most of the HIV-1-seropositive sera, including many that did not react with gp125 of HIV-2, reacted with gp140, the precursor of HIV-2 glycoproteins. The observed cross-reactions allowed us to distinguish three groups of HIV-1-infected individuals: (i) those whose sera react with both gp140 and gp125, (ii) those whose sera react with gp140, and (iii) those whose sera react with neither of these glycoproteins. The possible cause and significance of these differences is under study.

Cross Reactions↗
PubMed1988

Oxidation of Ferrous Iron and Elemental Sulfur by Thiobacillus ferrooxidans.

The oxidation of ferrous iron and elemental sulfur by Thiobacillus ferrooxidans that was absorbed and unabsorbed onto the surface of sulfur prills was studied. Unadsorbed sulfur-grown cells oxidized ferrous iron at a rate that was 3 to 7 times slower than that of ferrous iron-grown cells, but sulfur-grown cells were able to reach the oxidation rate of the ferrous iron-adapted cells after only 1.5 generations in a medium containing ferrous iron. Bacteria that were adsorbed to sulfur prills oxidized ferrous iron at a rate similar to that of unadsorbed sulfur-grown bacteria. They also showed the enhancement of ferrous iron oxidation activity in the presence of ferrous iron, even though sulfur continued to be available to the bacteria in this case. An increase in the level of rusticyanin together with the enhancement of the ferrous iron oxidation rate were observed in both sulfur-adsorbed and unadsorbed cells. On the other hand, sulfur oxidation by the adsorbed bacteria was not affected by the presence of ferrous iron in the medium. When bacteria that were adsorbed to sulfur prills were grown at a higher pH (ca. 2.5) in the presence of ferrous iron, they rapidly lost both ferrous iron and sulfur oxidation capacities and became inactive, apparently because of the deposition of a jarosite-like precipitate onto the surface to which they were attached.

Journal Article↗
PubMed1975

Alterations in normal esophageal motility in patients with Chagas' disease.

Eight adult patients with visceral Chagas' disease were studied twice within an interval of 64 months. In each case the esophagus was evaluated radiologically and manometrically. None of the patients had esophageal symptoms and no significant change in resting gastroesophageal sphincter pressure was observed during the study. However in 3 patients incomplete sphincteric relaxation was noted. Normal progressive contractions did not change. The importance of these findings are discussed.

Adult↗
PubMed1975

Bacteriology of the gallbladder bile in normal subjects.

A bacteriologic analysis of the gallbladder bile in eighty patients who underwent operation was performed in a prospective study. In all twenty patients with a normal gallbladder as assessed by oral cholecystography and intraoperative palpation, cultured were negative. Among patients with chronic cholecystitis only 30 per cent had positive bile cultures and this rose to 47 per cent among patients with acute cholecystitis.

Adult↗