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Biomedical subjects

E Calderón

Publications and source records attributed to E Calderón.

At least 73 records · Page 4Linked to original sources
PubMed1988

Serogroup specificity and antimicrobial susceptibilities of Neisseria gonorrhoeae isolated in Mexico City.

The serogroup pattern of 87 clinical isolates of Neisseria gonorrhoeae was determined by monoclonal coagglutination and the in-vitro activity of seven antimicrobial agents against the same strains was tested by an agar dilution method. The frequency of resistance to spectinomycin, ampicillin, penicillin, erythromycin, chloramphenicol and tetracycline was 14.9%, 33.3%, 34.4%, 30%, 40.2% and 41.3%, respectively. All strains were susceptible to cefotaxime. Out of 87 strains tested, 29.8% produced beta-lactamases and 4.5% were chromosomally resistant to penicillin. In all instances resistance to a drug was associated with serogroup 1-B except for erythromycin. The results presented here correlate with observations made worldwide.

Ampicillin↗
PubMed1988

Results of treatment of uncomplicated urogenital gonorrhoea with enoxacin compared with ceftriaxone.

The increasing incidence of penicillinase producing Neissreria gonorrhoeae (PPNG) and chromosomally-mediated resistant N. gonorrhoeae (CMRNG) has generated a need for therapy other than penicillin. PPNG constitutes about 30% of the circulating strains of gonococci in the high risk population in Mexico City. The object of the present study was to compare the safety and efficacy of single-dose treatment with either oral enoxacin (400 mg tablet) or intramuscular ceftriaxone (250 mg injection), for the treatment of acute uncomplicated gonococcal urethritis in men, caused by N. gonorrhoeae, including both PPNG and non-PPNG strains. Of the 93 men with uncomplicated gonorrhoea entered into a study, randomly assigned to receive ceftriaxone or enoxacin, 80 completed it. Infections were initially diagnosed by Gram-stained smears of urethral exudate and subsequently confirmed for isolation of N. gonorrhoeae. Chlamydia trachomatis was confirmed by direct immunofluorescence. About 30% of the strains of gonococci were PPNG and 1% were CMRNG. C. trachomatis was coexisting with N. gonorrhoeae in about 25% of the patients and remain positive after treatment. In the study presented, a single dose of either enoxacin or ceftriaxone was highly active against both PPNG or CMRNG. One single dose was enough to achieve a 100% cure rate. There was no difference between the two treatment groups. Thus either regimen has proved to be a useful alternative to the present-day treatment of uncomplicated gonococcal infections.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1987

Treatment of ordinary and penicillinase-producing strains of Neisseria gonorrhoeae in Mexico City.

Since being recognized in 1976 and 1983, respectively, penicillinase-producing strains of Neisseria gonorrhoeae (PPNG) and chromosomally mediated resistance (CMRNG) have attained a worldwide distribution. The high endemicity of both types of resistance in some regions precludes the continued routine use of procaine penicillin (APPG) as treatment for gonorrhea. In this study, we have evaluated 72/216 men with uncomplicated gonococcal urethritis at the venereal clinic in Mexico City. These men were part of a blinded randomized comparative study for treatment with group (P) penicillin having 33 patients and group (S) spectinomycin having 39. Efficacy with (P) was 24/33 (72.7%); nine failures retreated and were cured with spectinomycin. Efficacy with (S) was 35/39 (89.7%); four failures retreated and were cured with cefotaxime. We found correlation between MICs and resistance; all the strains with MICs of greater than or equal to 1.0 mcg/ml of penicillin failed to be cured, the MICs of greater than or equal to 32 mcg/ml of spectinomycin failed to be cured. The overall resistance to both regimens was 23/72 to penicillin (31.9%) (22 PPNG and one CMRNG) and 4/72 (5.5%) to spectinomycin.

Adolescent↗
PubMed1986

The effect of pH on the phase transition temperature of dipalmitoylphosphatidylcholine-palmitic acid liposomes.

The shift in the gel-liquid crystal phase transition temperature (tm) of dipalmitoylphosphatidylcholine liposomes induced by incorporation of 10 mol% palmitic acid, was measured by 90 degrees light scattering at different bulk pH values. It has been found that the tm shift decreases sigmoidally from 4.7 to -0.3 degrees C as the bulk pH is raised from 5 to 11. Since it is in this range that the carboxyl group of a membrane-bound fatty acid should ionize, our results can be interpreted to mean that there is relationship between the tm shift and the degree of dissociation of palmitic acid, the uncharged fatty acid increasing tm and its conjugate, anionic form, slightly decreasing the transition temperature of dipalmitoylphosphatidylcholine liposomes. The experimental results are fitted by a modified form of the Henderson-Hasselbach equilibrium expression which takes into account the effect of the anionic fatty acid on the surface potential and hence, on the surface pH of liposomes, according to Gouy-Chapman and Boltzmann equations, respectively. Best fit between theory and experiments is found when the intrinsic interfacial pK of palmitic acid is set equal to 7.7. This high pK value can be explained as due to the effect of the lower dielectric constant of the interfacial region, as compared to bulk water, on the acid-base dissociation of the carboxyl group. The results presented here show that upon incorporation of palmitic acid, the phase transition of dipalmitoylphosphatidylcholine bilayers becomes extremely sensitive to changes of pH in the vicinity of the physiological range. This property is not shown by the pure phospholipid bilayers in the same pH range.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1979

Presence of two distinct types of rotavirus in infants and young children hospitalized with acute gastroenteritis in Mexico City, 1977.

Between December 1976 and January 1978, infection with rotavirus was detected by electron microscopy in 61 (25%) of 242 infants and young children hospitalized with acute gastroenteritis at two hospitals in Mexico City. This type of infection was more frequent in autumn than in winter. The presence of virus could also be detected by the electrophoretic pattern of its segmented, double-standed ribonucleic acid (RNA) in the stool samples taken from 52 (85%) of the 61 patients who were shown by electron microscopic examination to excrete rotavirus. Two distinct patterns, previously called 2s and 21, were observed, which were distinguishable by the relative migration of the second, 10th, and 11th viral RNA segments in gel electrophoresis; the 21 pattern was observed much more frequently than with the 2s pattern.

Acute Disease↗
PubMedDate not supplied

Efficacy and safety of dipyrone versus tramadol in the management of pain after hysterectomy: a randomized, double-blind, multicenter study.

BACKGROUND AND OBJECTIVES: We assessed the efficacy and safety of dipyrone in comparison with tramadol in the relief of early postoperative pain following abdominal hysterectomy. METHODS: A total of 151 women between 18 and 60 years of age undergoing abdominal hysterectomy during general anesthesia participated in a randomized, double-blind, controlled, multicenter study. Seventy-three patients received dipyrone and 78 received tramadol. Patients received an intravenous loading dose of the study drug immediately after operation followed by intravenous (IV) maintenance infusion and IV on-demand boluses up to a maximum number of predetermined doses/day of 8 g dipyrone and 500 mg tramadol. The duration of the study was 24 hours. RESULTS: The mean (SD) number of boluses in the dipyrone group was 3.8 (2.4) and 3.5 (2.5) in the tramadol group (95% confidence interval, -0.455 to 1.175), and the percentage of patients requiring rescue IV morphine (dipyrone 26.9%, tramadol 26.8%) was not statistically significant. Other analgesic efficacy parameters, such as pain intensity differences, sum of pain intensity differences, pain relief assessed by the patient, or patients who required the maximum number of demand doses, were not different between treatment groups. A significantly higher percentage of adverse gastrointestinal effects was found in patients given tramadol (42.1%) than in patients given dipyrone (20.2%) (P <.05). Also, a significantly higher number of tramadol-treated patients required ondansetron to control nausea and vomiting at 1 hour (19% v 7%), 2 hours (26% v 11%), and 24 hours (46% v 29%) (P <.05) after surgery. Patients and the investigators reported similar tolerability for both study arms. CONCLUSIONS: Dipyrone and tramadol showed similar efficacy for early pain relief after abdominal hysterectomy. Nausea and vomiting, possibly caused by the tramadol, occurred more frequently in those patients. In this group, the need of the antiemetic drug ondansetron was also higher.

Adolescent↗