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Biomedical subjects

C Torres

Publications and source records attributed to C Torres.

At least 91 records · Page 5Linked to original sources
PubMed1999

Efficacy of ampicillin plus ceftriaxone in treatment of experimental endocarditis due to Enterococcus faecalis strains highly resistant to aminoglycosides.

The purpose of this work was to evaluate the in vitro possibilities of ampicillin-ceftriaxone combinations for 10 Enterococcus faecalis strains with high-level resistance to aminoglycosides (HLRAg) and to assess the efficacy of ampicillin plus ceftriaxone, both administered with humanlike pharmacokinetics, for the treatment of experimental endocarditis due to HLRAg E. faecalis. A reduction of 1 to 4 dilutions in MICs of ampicillin was obtained when ampicillin was combined with a fixed subinhibitory ceftriaxone concentration of 4 micrograms/ml. This potentiating effect was also observed by the double disk method with all 10 strains. Time-kill studies performed with 1 and 2 micrograms of ampicillin alone per ml or in combination with 5, 10, 20, 40, and 60 micrograms of ceftriaxone per ml showed a > or = 2 log10 reduction in CFU per milliliter with respect to ampicillin alone and to the initial inoculum for all 10 E. faecalis strains studied. This effect was obtained for seven strains with the combination of 2 micrograms of ampicillin per ml plus 10 micrograms of ceftriaxone per ml and for six strains with 5 micrograms of ceftriaxone per ml. Animals with catheter-induced endocarditis were infected intravenously with 10(8) CFU of E. faecalis V48 or 10(5) CFU of E. faecalis V45 and were treated for 3 days with humanlike pharmacokinetics of 2 g of ampicillin every 4 h, alone or combined with 2 g of ceftriaxone every 12 h. The levels in serum and the pharmacokinetic parameters of the humanlike pharmacokinetics of ampicillin or ceftriaxone in rabbits were similar to those found in humans treated with 2 g of ampicillin or ceftriaxone intravenously. Results of the therapy for experimental endocarditis caused by E. faecalis V48 or V45 showed that the residual bacterial titers in aortic valve vegetations were significantly lower in the animals treated with the combinations of ampicillin plus ceftriaxone than in those treated with ampicillin alone (P < 0.001). The combination of ampicillin and ceftriaxone showed in vitro and in vivo synergism against HLRAg E. faecalis.

Algorithms↗
PubMed1999

From vanA Enterococcus hirae to vanA Enterococcus faecium: a study of feed supplementation with avoparcin and tylosin in young chickens.

Fifteen newborn chickens were isolated in separate cages after 1 month of living together, divided into three groups, and challenged for 5 weeks with seed food which either was supplemented with avoparcin (10 mg/kg of animal food) or tylosin (40 mg/kg) or was nonsupplemented. At 9 weeks of age and after the 5-week challenge, all chickens received nonsupplemented feed for 4 additional weeks. At 4, 9, and 13 weeks of life, feces were collected and inoculated on M-Enterococcus agar plates with and without vancomycin (4 micrograms/ml). vanA-containing Enterococcus hirae was isolated from 11 of 15 chickens before antibiotic challenge, without detection of vancomycin-resistant Enterococcus faecium. At 9 weeks of age and after the 5-week avoparcin challenge, vanA E. hirae strains were no longer detected, but five of five chickens now had vanA E. faecium. At a lower frequency, vanA E. faecium had also displaced vanA E. hirae in both the tylosin group (one of four chickens) and the control group (two of five chickens). One month after avoparcin discontinuation, the number of chickens colonized with vanA E. faecium decreased from five to one. All vanA-containing E. hirae strains detected in the first month of life and most of the vanA-containing E. faecium strains detected in the second month of life showed identical ApaI and SmaI restriction patterns, respectively, when analyzed by pulsed-field gel electrophoresis. All vanA E. hirae isolates transferred glycopeptide and macrolide resistance to Enterococcus faecalis JH2-2 in vitro; the level of glycopeptide resistance was higher in the transconjugants than in the donor E. hirae strains. These data suggest that E. hirae may be a significant source of vanA determinants with the potential of transfer to other enterococcal species from humans or animals.

Animals↗
PubMed1999

[Sexual aggression in adolescents. Epidemiologic study].

Sexual assault is an enormous social and public health problem. Most victims are young women. The aim of this study was to describe the characteristics of this crime in adolescents. The study involved 213 patients separated in two subgroups: adolescents and non adolescents. In adolescents, much of this violence is perpetrated by an acquaintance or relative. Th frequency of sexually transmitted diseases was 20% and rape-related pregnancy was identified in 10% of victims. All victims of sexual assault must be encouraged for both medical and psychological evaluation.

Adolescent↗
PubMed1998

Genotoxic activity of four inhibitors of DNA topoisomerases in larval cells of Drosophila melanogaster as measured in the wing spot assay.

Four inhibitors of DNA topoisomerases namely nalidixic acid, camptothecin, m-amsacrine and etoposide, have been evaluated for genotoxic effects in the wing spot test of Drosophila melanogaster. This assay assesses somatic recombination and mutational events. We studied nalidixic acid as an inhibitor of bacterial DNA gyrase, camptothecin as a topoisomerase I inhibitor, as well as m-amsacrine and etoposide as topoisomerse II inhibitors. The genotoxic effects were determined from the appearance of wing spots in flies trans-heterozygous for the recessive markers multiple wing hairs (mwh) and flare, as well as in flies heterozygous for mwh and the multiply inverted TM3 balancer chromosome. From our results it appears that whilst nalidixic acid and m-amsacrine were compounds that did not increase the incidence of mutant clones, camptothecin and etoposide proved to be significantly genotoxic in this test, being camptothecin more effective than etoposide. A significant proportion of the total spot induction was due to mitotic recombination, confirming previously reported data. On the other hand, the cotreatments of each topoisomerase inhibitor with the alkylating agent ethyl methanesulfonate (EMS) indicate that, while nalidixic acid, m-amsacrine and etoposide show a tendency to an antagonistic interaction, camptothecin shows an additive effect, suggesting mechanistic differences between the activity of the four inhibitors of DNA topoisomerases studied.

Amsacrine↗
PubMed1998

Polypoid dysplasia and adenomas in inflammatory bowel disease: a clinical, pathologic, and follow-up study of 89 polyps from 59 patients.

Dysplasia in inflammatory bowel disease (IBD) is categorized as either flat or associated with a raised lesion or mass (dysplasia-associated lesion or mass [DALM]). One specific subtype of a dysplasia-associated lesion or mass consists of isolated discrete nodules or polyps that are difficult to distinguish from sporadic adenomas. Because the clinical management of these two lesions is different, we performed this study to (1) evaluate the clinical presentation, pathologic features, and natural history of polypoid dysplastic lesions and sporadic adenomas in patients with IBD and (2) determine whether there are clinical, endoscopic, or pathologic findings useful in differentiating between these two lesions. The morphologic features of 89 benign polypoid epithelial neoplasms from 59 patients with IBD (51 with ulcerative colitis, 8 with Crohn's colitis) were evaluated and correlated with the clinical, endoscopic, and follow-up data. In a separate analysis, patients were categorized arbitrarily as having (1) a probable sporadic adenoma if the polypoid epithelial neoplasm was not located within areas of histologically proven colitis, (2) a probable IBD-associated polypoid dysplasia if the lesion developed within an area of colitis, and associated flat dysplasia or an adenocarcinoma was detected during follow-up evaluation or (3) an indeterminate polyp, which was seen in the remainder of the cases. The clinical, endoscopic, and histologic data were compared among these three patient and polyp subgroups. There were 35 males and 24 females (median age, 57 years; range, 27-85 years). Median duration of disease was 10 years. Forty-nine percent of the patients had pancolitis; 66% had histologically active disease at the time of presentation. Nearly 70% of patients had only one polyp; the majority occurred in either the left colon or the rectum (66%). Most polyps were described as a sessile nodule, whereas only 7 (7.8%) were pedunculated. Polyps ranged from 2 mm to 50 mm (median, 5 mm); most had a tubular architecture (84.3%) and contained low-grade dysplasia (64%). In addition, most polyps had mildly increased lamina propria and intraepithelial neutrophilic and mononuclear inflammation. At follow-up evaluation (40 patients; median follow-up time, 13 months; range, 1-78 months), a further neoplastic lesion developed in 20%; low-grade flat dysplasia was seen in 5 (12.5%), and adenocarcinoma developed in 3 (7.5%). However, dysplasia or adenocarcinoma did not develop in the patients who had polyps located outside of areas of histologically proven colitis. In addition, at least one more benign polypoid epithelial neoplasm developed in 15 of 40 patients (37.5%). Patients with probable IBD-associated polypoid dysplasia had a statistically significant (p < 0.05), longer disease duration than patients with probable sporadic adenoma. A statistically significant, higher proportion of polyps with tubullovillous or villous architecture, an admixture of normal and dysplastic epithelium at the surface of the polyps, and increased lamina propria mononuclear inflammation was noted in probable IBD-associated polypoid dysplastic lesions compared with those considered to be sporadic adenomas. Several clinical and pathologic features may be useful to help categorize a polypoid dysplastic lesion as a sporadic adenoma or an IBD-related neoplasm in a patient with IBD. This distinction is important because the natural history of these two lesions (as shown by the results of this study) and their subsequent management are quite different.

Adenoma↗
PubMed1998

In vitro activity of the new ketolide HMR3647 in comparison with those of macrolides and pristinamycins against Enterococcus spp.

Ninety-four erythromycin-susceptible and 107 erythromycin-resistant enterococcal strains (MIC of >/=512 microgram/ml) were inhibited by the ketolide HMR3647 at MICs of </=0.007 to 0.06 and 0.03 to 8 microgram/ml, respectively. Eighteen vanA-positive isolates and 29 high-level-penicillin-resistant isolates, all of them erythromycin resistant, were inhibited by HMR3647 at an MIC range of 0.015 to 4 microgram/ml. The new ketolide has excellent activity against Enterococcus species.

Anti-Bacterial Agents↗
PubMed1998

[Prevalence of celiac disease in diabetic children and adolescents].

BACKGROUND: Celiac disease is more common in patients with insulin dependent diabetes than in the general population. AIM: To detect celiac disease in diabetic children and adolescents. PATIENTS AND METHODS: IgA antigliadin, IgG antireticulin and IgG antiendomysium antibodies were measured in 67 diabetic children (35 female), aged between 4 and 18 years old. RESULTS: Only one male adolescent, aged 18 years old, without gastrointestinal symptoms, had a significant elevation of antireticulin and antiendomysium antibodies. His intestinal biopsy showed subtotal villous atrophy, consistent with celiac disease. CONCLUSIONS: The prevalence of celiac disease in these diabetic children is 1:67 (1.5%). Similar figures have been reported elsewhere.

Adolescent↗
PubMed1998

Increasing radiosensitivity in the course of fractionated X irradiation: the effect of contact with dead and dying cells.

We have measured survival after successive 2-Gy doses of X rays in HeLa cells and 1-Gy doses in cells of the nonimmortalized human fibroblast cell line AG15-22 under conditions where any effect of cell proliferation during multifraction X irradiation has been factored out. When HeLa cells in parallel series of (pseudo)hybrid spheroids (i.e. in agglomerates consisting of a mixture of supralethally irradiated HeLa feeder and viable HeLa cells) were exposed to n daily radiation doses and then trypsinized and exposed to the last dose, the surviving fraction at 2 Gy (SF2) declined exponentially from 0.55 +/- 0.01 to 0.31 +/- 0.01 after the fifth fraction. In monolayer HeLa cell cultures, the decline in SF2 was smaller but significant and was not influenced by the presence of feeder cells. Pure spheroids, composed entirely of viable HeLa cells, showed the same decline in SF2 as did monolayer cells. The cumulative-effect curve (i.e. the product of SF2 values) was linear-quadratic with the quadratic term increasing in the order monolayer, pure spheroids, pseudohybrid spheroids. SF2n and D0Eff (deduced from the initial SF2) severely underestimated cumulative radiosensitivity. This cumulative effect is clearly associated with the proximity of lethally irradiated cells and might be explained by differential population shifts in the course of the multifraction regimen. Similarly, AG15-22 cells irradiated with daily 1-Gy doses of X rays showed a larger increase in radiosensitivity when in hybrid spheroids than when in pure spheroids. However, for the AG15-22 cells, SF1 was twofold lower for the former than for the latter condition and remained constant for both conditions rather than decreasing with increasing fraction number. This large radiosensitizing effect remains unexplained.

Cell Communication↗
PubMed1998

Epidemiology and prevalence of seropositivity for hepatitis C virus in pregnant women in Granada.

OBJECTIVES: To study personal and familial antecedents of risk and prevalence of infection by HCV in pregnant women in the south area of Granada. PATIENTS AND METHODS: We included in the study 3003 pregnant women of the south area of Granada during the period from January 1993 to December 1995. Anti-HCV was detected in the third trimester of pregnancy by second and third generation ELISA, and positive results were confirmed by RIBA 3. We also determined HCV-RNA and genotype. Finally, we analyzed ALT levels in 1171 (39%) pregnant women. We carried out an epidemiological survey of all pregnant women, which included the following personal antecedents: transfusion, intravenous drug use, liver diseases, risk profession and sexually transmitted diseases. We studied the same antecedents in the parents, husbands and other relatives. RESULTS: Prevalence of anti-HCV was 0.63% (19 cases) with ELISA and 0.53% with RIBA. HCV-RNA was positive in 14 (74%) genotype 1b (57%) being the most frequent. ALT was increased in 52 (4.4%) pregnant women, 7 (13.5%) of whom were anti-HCV positive, versus 12 women (1%) in the normal ALT group (p < 0.001). In the epidemiological study we observed statistically significant differences in: a) housing characteristics [2125 (71%) anti-HCV negative pregnant women living in occupant-owned housing versus 7 (36%) in anti-HCV-positive group, p < 0.001]; b) personal antecedents of transfusion, chronic or acute hepatitis, or intravenous drug use (p < 0.001) (these factors were confirmed in the multivariable analysis), and c) familial antecedents of the husband (p < 0.05). CONCLUSIONS: In this study we demonstrated that 0.53% of the pregnant women were infected by HCV; most of them were HCV-RNA positive and was genotype 1b was the most frequent. The risk factors most frequently associated with infection were antecedents of transfusion, intravenous drug use and acute or chronic hepatitis.

Female↗
PubMed1997

Concomitant infusion cisplatin and hyperfractionated radiotherapy for locally advanced nasopharyngeal and paranasal sinus tumors.

PURPOSE: This is a prospective study to improve the therapeutic ratio in the treatment of patients with locally advanced nasopharyngeal and paranasal sinus tumors by using split-course concomitant infusion cisplatin chemotherapy and hyperfractionated radiotherapy. METHODS AND MATERIALS: From 1983 to 1993, 21 patients with locally advanced nasopharyngeal and paranasal sinus tumors (T3 and T4, or recurrent tumors involving the facial bones and/or the base of the skull) were treated with a regimen of split-course hyperfractioned radiotherapy (1.2 Gy/fraction/bid) and concomitant infusion cisplatin (5-10 mg/m2/24 h). The therapy was given in three separate 2-week sessions with 1 to 2 week breaks between sessions. Seventeen of 21 patients were treated with curative intent with cumulative radiation doses ranging from 64.8 to 70.8 Gy. Four patients were treated with palliative intent to a total dose of less than 60 Gy or to a limited field due to previous irradiation. RESULTS: Sixteen of 17 patients (94%) treated curatively achieved a complete response. Of the 16 patients who achieved complete response, 7 patients (50%) were alive at the time of analysis (36 to 126 months). One patient was alive at 4 years with no evidence of disease, and died in 10 years at the age of 80 of unknown cause. Two patients died of local recurrence at 21 and 45 months and one patient died of a cerebrovascular accident at 12 months with disease status unknown. Five patients died of distant metastases. The one patient who had a partial response died in 25 months with local disease and metastases to the bone and lung. Four patients that were previously irradiated received a reduced total dose or treated to a limited irradiation field. All had near complete responses, but died within a year of treatment, with the exception of one patient who died at 23 months. Acute reactions included intense erythema of the mucosa in all patients. Five of 21 (23%) developed punctate mucositis and 3 of 21 (14%) developed confluent mucositis. Hematologically, one patient developed neutropenia (1800 WBC/mm3) and one developed thrombocytopenia (38,000/mm3). A rising creatinine was observed in three patients (2.0, 1.7, 1.7) all of whom were treated with the higher 10 mg/m2/day dose of infusional cisplatin. In all three of these cases, the creatinine slowly returned to normal over a 6-month period. Hormonal evaluations were performed in three patients and all were within normal ranges. There was no evidence of neck fibrosis or trismus. One patient with gross recurrent disease of the orbit developed blindness of the involved eye due to corneal opacification. The orbital area had been reirradiated in this patient. CONCLUSIONS: Concomitant infusion cisplatinum with hyperfractionated radiation improved tumor control, but did not increase normal tissue injury. Acute reactions were minimized by splitting the treatment with a 1- to 2-week break after each 2 weeks of radiation treatment. Late complications were not increased by using a hyperfractionated radiation regimen. The local failure rate was only 18% (3 of 17 patients), but the distant failure rate was 35% (6 patients). Further investigation is needed to prove if adjuvant chemotherapy after concomitant chemoradiation improves survival by decreasing the distant failure in such advanced cases.

Antineoplastic Agents↗
PubMed1997

Determination of HCV RNA concentration by direct quantitation of the products from a single RT-PCR.

A novel method for the estimation of HCV RNA levels in vivo was developed, based on competitive RT-PCR. The use of the Tth DNA polymerase and 5' 32P-labeled antisense primer respectively reduced cross-contamination and permitted the direct quantification of viral loads by the analysis of the radioactivity of PCR products derived from a clinical sample and a competitive deleted template, separated previously on a polyacrilamide gel. A HCV fragment (H) and a competitive (deltaH) RNA templates were synthesized for optimizing the method. The minimal starting RNA detectable by RT-PCR was 40 copies. RT-PCR performed with ratios deltaH/H ranging from 1/1 to 1/20 revealed different relative percentages of both H and deltaH products, changing from 90% of deltaH product when the ratio was 1/1 to 5%, when it was 1/20. Regression analysis was adjusted to a linear model and served to further estimate HCV RNA loads from clinical samples. HCV RNA quantitation was carried out in 19 patients. Higher viral loads were related to type 1b infection and persistence of HCV RNA after interferon therapy. This method is simple, reproducible and useful for rapid estimation of HCV RNA load in vivo.

Antiviral Agents↗
PubMed1997

Vascular adrenal cysts: a clinicopathologic and immunohistochemical study of six cases and a review of the literature.

The clinical, histologic, and immunohistochemical features of six cases of hemorrhagic adrenal pseudocysts are reported together, with a review of the English literature on this topic since 1950. The mean age at presentation was 57 years (range, 30-72 yr). There were four men and 2 women. The average cyst size was 9.2 cm (range, 6-16 cm). In four patients, the hemorrhagic adrenal pseudocysts were incidental findings. The remaining two patients presented with an abdominal mass and hypertension, respectively. The hemorrhagic pseudocysts were unilocular cystic masses surrounded by a fibrous capsule and containing abundant amorphous material, blood, and fibrin. Numerous dilated, thin-walled, vascular channels that stained strongly for Factor VIII-related antigen, collagen IV, laminin, Ulex europaeus agglutinin I lectin, and CD34 were present within the fibrous capsule, cyst contents, and surrounding residual adrenal gland. These findings support a vascular origin for these lesions, and they are thought, therefore, to be related to endothelial adrenal cysts. The literature review of 111 vascular adrenal cysts (85 hemorrhagic pseudocystic type and 26 endothelial type) showed similar clinical features. The mean age at presentation was 44.5 years (range, 5 d-95 yr), with a female predominance (62%). The most common clinical presentation was abdominal pain (35%), followed by incidental findings (32%). There were no significant clinical differences between hemorrhagic and endothelial type cysts. In some cases, the presence of intracystic islands of cortical cells can cause diagnostic confusion with adrenal cortical tumors. The presence, however, of a rich intracystic and capsular vascular network, normal-appearing islands of cortical cells, and abundant thrombotic fibrinous material, rather than necrotic tumor cells, should rule out the possibility of a degenerating adrenal cortical neoplasm.

Adrenal Gland Diseases↗
PubMed1997

Effect of standard rest periods on apnea and weight gain in preterm infants.

This study determined the effect of modifying a single aspect of the intermediate care environment on the incidence of apnea and rate of weight gain in convalescent preterm infants. Twenty-two preterm infants were assigned to experimental and control groups using a randomized, matched-pair design. Over a three-week period, infants in the experimental group were provided a 1 1/2-hour nap period four times a day during which their beds were covered and they were left undisturbed. Control infants received standard nursing care. The infants in the experimental group had more apnea at the start of the study than the control infants but showed a significantly more rapid decline in the incidence of apnea. These infants also gained significantly more weight per day than the control infants. Thus, a simple modification of nursing care that involved minimal increases in nursing time had a beneficial effect on preterm infants.

Apnea↗
PubMed1996

Successive negative contrast in one-way avoidance: effect of thiopental sodium and chlorpromazine.

The successive negative contrast effect on one-way avoidance was induced by shifting rats from a large reward (30 s spent in the safe compartment after completion of the avoidance response, pre-shift phase) to a small reward (1 s, post-shift phase). Under these conditions, the previously learned avoidance response deteriorated (negative contrast) when compared to a control group for which 'safe time' remained constant throughout the experimental situation (1 s). Thiopental sodium at a dose of 5 or 10 mg/kg, but not at 1, 2, 15 or 20 mg/kg i.p., abolished the negative contrast effect, and did not affect performance of the one-way avoidance task. Similar results were found when rats were treated with diazepam (1 mg/kg i.p.). Chlorpromazine at a dose of 0.5 or 1 mg/kg i.p. did not affect negative contrast, although at higher doses (2 or 3 mg/kg) there was an increase in the number of trials needed to reach the criterion for learning the avoidance response. This increase was evident in both pre-shift and post-shift phases, although only in the experimental situations involving a low level of reinforcement (1 s in the safe compartment). On the basis of these results, we tentatively suggest that the successive negative contrast effect in one-way avoidance in rats can be considered a useful pharmacological animal model for research into anxiety.

Animals↗