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Biomedical subjects

E Calderón

Publications and source records attributed to E Calderón.

At least 19 recordsLinked to original sources
PubMed2004

Pneumocystis jiroveci isolates with dihydropteroate synthase mutations in patients with chronic bronchitis.

Since mutations in the dihydropteroate synthase (DHPS) gene possibly associated with sulfonamide resistance have been reported in patients with Pneumocystis jiroveci (previously carinii) pneumonia, and since P. jiroveci colonization has been recently demonstrated in patients with chronic pulmonary diseases, the present study aimed to investigate the possible occurrence of P. jiroveci DHPS mutations in patients with chronic bronchitis. P. jiroveci colonization was detected in 15 of 37 non-selected patients with chronic bronchitis by amplifying the large subunit of the mitochondrial gene of the ribosomal RNA using nested PCR. DHPS mutations were demonstrated using touchdown PCR and restriction enzyme analysis in two of eight patients with chronic bronchitis and in two of six patients from the same region who had AIDS-associated Pneumocystis pneumonia. In all cases, mutations were observed in subjects with no prior exposure to sulfonamides. These data could have important implications for public health, since (i) P. jiroveci colonization could speed the progression of chronic bronchitis, and (ii) these patients, who are customary sputum producers, could represent a reservoir for sulfonamide-resistant strains with the potential ability to transmit them to immunocompromised hosts susceptible to Pneumocystis pneumonia.

Age Distribution↗
PubMed2003

Occurrence and densities of bacteriophages proposed as indicators and bacterial indicators in river waters from Europe and South America.

AIMS: To evaluate the feasibility of bacteriophages as a complementary tool for water quality assessment in surface waters from different parts of the globe. METHODS AND RESULTS: Faecal coliform bacteria, enterococci, spores of sulphite-reducing clostridia, somatic coliphages, F-specific RNA bacteriophages and bacteriophages infecting Bacteroides fragilis were determined by standardized methods in raw sewage and in 392 samples of river water from 22 sampling sites in 10 rivers in Argentina, Colombia, France and Spain, which represent very different climatic and socio-economic conditions. The results showed that the indicators studied maintained the same relative densities in the raw sewage from the different areas. Classifying the river water samples according to the content of faecal coliform bacteria, it can be observed that the relative densities of the different bacterial indicators and bacteriophages changed according to the concentration of faecal coliform bacteria. There was a relative increase in the densities of all groups of bacteriophages and sulphite-reducing clostridia with respect to faecal coliforms and enterococci in the samples with low counts of faecal coliform bacteria. CONCLUSIONS: The numbers of bacterial indicators and bacteriophages were similar in the different geographical areas studied. Once released in rivers, the persistence of the different micro-organisms differed significantly. Bacteriophages and spores of sulphite-reducing clostridia persisted longer than faecal coliforms and enterococci. SIGNIFICANCE AND IMPACT OF THE STUDY: Bacteriophages in river water samples provide additional information to that provided by bacteria about the fate of faecal micro-organisms in river water. The easy, fast and cheap methods for phage determination are feasible both in industrialized and developing countries.

Bacteriophages↗
PubMed2003

[Analgesia and sedation in the subarachnoid anesthesia technique: comparative study between remifentanil and fentanyl/midazolam].

OBJECTIVE: To assess the efficacy and safety of remifentanil in comparison with fentanyl-midazolam for analgesia and sedation during subarachnoid anesthesia. MATERIAL AND METHODS: Sixty ASA I-III patients between 25 and 75 years old and scheduled for inguinal hernia repair were enrolled. Before the subarachnoid block, the patients were randomly assigned to receive an intravenous infusion of 0.1 microgram.Kg-1.min.-1 of remifentanil (group R) or 1 microgram.Kg-1 of fentanyl and 0.02 mg.Kg-1 of midazolam (group F). Ten minutes later a subarachnoid block to L3-L4 was performed with 10 mg of hyperbaric bupivacaine. We recorded intensity of pain during performance of the block on a simple verbal scale, the observer's assessment of alertness/sedation (OAA/S), hemodynamic variables, respiratory frequency and SpO2, level of comfort and side effects. RESULTS: Over 70% of patients had no pain or slight pain during the subarachnoid puncture and absence of pain was significantly greater in group R than in group F (37% vs. 16%, p < 0.05). Sedation was adequate during surgery in both groups (OAA/S 2-3). There were no differences in level of comfort between the two groups. The incidences of hypoxemia, hypoventilation and excessive sedation were significantly higher in group R (40%, 20% and 16%, respectively; p < 0.05). CONCLUSIONS: Remifentanil is more effective for treating pain associated with a subarachnoid block and provides cardiovascular stability with a limited level of sedation per dose, but its use is associated with a high incidence of respiratory depression.

Adult↗
PubMed2002

[Acute selective tolerance to remifentanil after prolonged infusion].

We describe the cases of 3 patients who received anesthesia with remifentanil continuously infused at rates of 0.8 to 1.25 micrograms.kg-1.min-1 for at least 3 hours. Upon emergence from anesthesia, after withdrawal of the anesthetic gas, satisfactory levels of consciousness, spontaneous breathing and absence of pain were achieved under maintenance doses of remifentanil greater than 0.8 microgram.kg-1.min-1; such doses are related to the development of ventilatory depression, apnea and significant sedation. Acute tolerance to remifentanil is under debate at present. Such tolerance involves decreased efficacy of an opiate or the need for higher doses to maintain an effect after exposure. The development of tolerance is related mainly to the pharmacokinetics of an opiate, a short half-life and infusion periods exceeding 3 hours, and in the case of remifentanil, to the use of high doses. The most likely explanation for de phenomena described would be the development of selective acute tolerance to ventilatory depression and to sedation, with no effect on the antinociceptive effects of remifentanil. Clinical trials should be carried out to assess the development of acute tolerance to remifentanil and its possible perioperative repercussions.

Acute Disease↗
PubMed2001

A comparison of two constant-dose continuous infusions of remifentanil for severe postoperative pain.

UNLABELLED: We evaluated the analgesic efficacy and safety of two continuous constant-dose infusions of IV remifentanil, without infusion rate increments or the addition of boluses, in patients with severe postoperative pain during the first 4 h after general anesthesia with IV propofol-remifentanil. Thirty patients were randomly assigned to two groups of 15 subjects each according to the remifentanil dose administered: 0.1 microg. kg(-1). min(-1) IV (Group A) or 0.05 microg. kg(-1). min(-1) IV (Group B). Rescue analgesia was provided with meperidine (0.5 mg/kg IV) when pain intensity on the simple verbal scale (SVS) > or =2. The criteria for adequate analgesia (SVS 0-1, respiratory frequency >8/min. and SpO(2) >90%) after 4 h were met by 78% and 75% of the patients in Groups A and B, respectively (P = ns). "Meperidine rescue" analgesia was significantly more in Group B (26%) than in Group A (6%) (P < 0.05). There were no cases of respiratory depression, and nausea and emesis occurred in one patient in each group (6.5%). We conclude that IV remifentanil is an effective and safe opioid for the treatment of postoperative pain at a constant dose of 0.1 microg. kg(-1). min(-1) with a need for rescue analgesia 4 times less than a constant dose of 0.05 microg. kg(-1). min(-1). IMPLICATIONS: Our study suggests that the use of a constant continuous infusion of remifentanil 0.1 microg.kg(-1).min(-1)IV is an effective alternative in the treatment of severe postoperative pain.

Adult↗
PubMed1999

Analysis of herpes simplex virus 1 and 2 infection in women with high risk sexual behaviour in Mexico.

BACKGROUND: This paper describes the seroprevalence and risk factors of Herpes simplex virus (HSV) infection in a group of female prostitutes from Mexico City. METHODS: Women who consented to participate in the study voluntarily attended a sexually transmitted disease (STD) clinic during 1992. A standardized questionnaire was administered and a blood sample was obtained from each participant. Type-specific Western blot serology was performed to determine the serostatus of HSV-1 and HSV-2 for participants. Bivariate and multivariate analyses were applied to identify variables associated with an increased risk for HSV infection. RESULTS: Prevalences of infection among the 997 prostitutes studied were 93.9% for HSV-1 and 60.8% for HSV-2. Only 1.8% of the women were seronegative for both viruses. The only variable associated with HSV-1 seropositivity was crowding index. The following variables were associated with an increased risk for infection with HSV-2: age, level of education, working site, born outside Mexico City and increasing time as a prostitute. CONCLUSIONS: This is the first assessment of HSV infection in Mexico and may be useful for the development and application of control and preventive measures among the prostitute population at risk of acquiring and transmitting human immunodeficiency virus (HIV) and other STD.

Adolescent↗
PubMed1999

[Remifentanyl. Indications in anesthesia].

Remifentanil is a new opioid in the fentanyl family. Developed and marketed by Glaxo Wellcome Inc., it was approved by the U.S. Food and Drug Administration in July 1996 and has been available for use in Spain since the end of 1997. Remifentanil is an analog of fentanyl (4-piperidyl anilide) with a methyl-ester group that allows the molecule to be hydrolyzed by esterases in plasma and tissues. Rapid onset and metabolism make it an easy drug to control for achieving the desired depth of anesthesia, although these aspects are also the drug's main drawbacks given that the anesthesiologist must plan and initiate postoperative analgesia before surgery ends. Rapid onset and potency also mean that the use of this drug for either postoperative analgesia or monitored sedation in awake state with spontaneous breathing needs further study to assess safety.

Analgesics, Opioid↗
PubMed1998

Low prevalence of hepatitis B markers among Mexican female sex workers.

OBJECTIVES: To estimate the prevalence and associated risk factors of hepatitis B virus (HBV) serological markers in female sex workers (FSW) in Mexico City. METHODS: The study population consisted of 1498 FSW who attended a detection centre for human immunodeficiency virus (HIV) in Mexico City, between January and October 1992. Study participants responded to a standardised questionnaire and provided a blood sample for serology of syphilis, HIV, and HBV. RESULTS: A total of 0.2% (95% CI 0.1-0.3) of the population were hepatitis B surface antigen (HBsAg) carriers. The general prevalence of antibodies to hepatitis B core antigen (anti-HBc) was 6.3% (95% CI 5.5-7.1). This marker of previous exposition to HBV, was independently associated by logistic regression multivariate analysis with age, working in the street, and history of blood transfusion (BT) before 1987 (OR 4.8, 95% CI 2.1-11.3). Syphilis prevalence was 7.6% (95% CI 6.2-8.9) and HIV prevalence was 0.1% (95% CI 0-0.3). CONCLUSIONS: The prevalence of HBV infection in this group of Mexican FSW is lower than previously reported in other countries. In addition, the frequency of HBsAg carriers is similar to that in the general Mexican population. The absence of two major risk factors for HBV transmission in this group of FSW--that is, injecting drug use and anal intercourse, could help to explain this finding. However, the positive association between anti-HBc and history of blood transfusion demonstrated here, highlights the need to reinforce strict control of blood supplies in Mexico.

Adolescent↗