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F Delgado

Publications and source records attributed to F Delgado.

At least 37 records · Page 2Linked to original sources
PubMed1999

Lack of lymphoid cell apoptosis in the pathogenesis of tonsillar hypertrophy as compared to recurrent tonsillitis.

UNLABELLED: The pathogenic mechanism of tonsillar hypertrophy is unknown and lacks a proper infectious or immunological explanation. Epidemiological studies point to polluted environments as the main cause of tonsillar hypertrophy in the adaptation of the juvenile organism. Tonsils and adenoids of 67 children aged 2-16 years (mean 5.9 years) were divided into three groups: recurrent tonsillitis (n = 21), recurrent tonsillitis with tonsillar hypertrophy (n = 21) and tonsillar hypertrophy without history of tonsillitis (n = 25). The following biological markers were studied: anti-streptolysin O antibody and anti-deoxy ribonuclease B antibody serology, microbiology and cell count of granulocytes in tonsils and adenoids as well as lymphocyte subsets and "ex vivo" endonuclease activity in tonsils. Anti-streptolysin O antibody and anti-deoxyribonuclease B antibody titres were significantly raised in recurrent tonsillitis. Positive bacterial cultures for Streptococcus pyogenes were rare in cases of tonsillar hypertrophy. T-lymphocytes counts were lower and the proportion of basophils was higher in hypertrophic tonsils than in recurrent tonsillitis. Two parameters of apoptosis were studied; the activation of endonuclease, inducing breakdown of DNA resulting in cell death, and the sensitivity to thapsigargin, known to trigger the cleavage of DNA by apoptotic endonuclease. In children with tonsillar hypertrophy both parameters were decreased contrasting with those with recurrent tonsillitis where apoptosis is increased. It may be speculated that the increase of basophils in children with tonsillar hypertrophy results in increased release of interleukin-4, which could prevent lymphoid apoptosis and lead to cell proliferation in tonsillar tissue. CONCLUSION: Whereas recurrent tonsillitis is characterised by apoptotic death of lymphoid tissue, tonsillar hypertrophy is caused by environmental pollution agents that trigger the chronic inflammatory process without apoptotic cell death.

Apoptosis↗
PubMed1999

Aminoglycosides activate oxygen metabolites production in the cochlea of mature and developing rats.

The ototoxicity of antibiotics, particularly of aminoglycosides, is a well-known undesirable side effect which may be based on a free radical mechanism. We studied the effect of different antibiotics in the production of reactive oxygen species in freshly isolated cochleas of mature and 2-10 weeks old developing rats. Phorbol myristate acetate induced the release of reactive oxygen species after a lag time close to 30 s and declined back to basal values in 10-20 min. The rate of reactive oxygen species production correlated inversely to the age in 2-10 weeks old rats. The study of a set of antibiotics showed that a very low concentration of gentamicin and streptomycin (10-100 ng/ml) enhanced the effect of phorbol myristate acetate. At the above-indicated concentrations, ciprofloxacin did not modify phorbol myristate acetate-induced activation. These results show the enhancement by aminoglycosides of reactive oxygen species production in cochlear tissues, particularly in developing rats.

Aging↗
PubMed1999

Autoimmune deafness is not related to hyperreactivity to type II collagen.

The pathogenic role of anti-type II collagen was analysed in a variety of hearing losses, in age-matched controls and in different autoimmune diseases. The immune reactivity of peripheral blood lymphocytes to type II collagen was studied by the degree of proliferation measured as the incorporation of bromodeoxyuridine in cultured lymphocytes. The anti-type II collagen antibodies showed a very low incidence in the hearing loss group. Lymphocytes of otosclerosis, Meniere's disease and other sensorineural deafness patients proliferated in response to concanavalin A and to type II collagen to a lower extent than peripheral blood lymphocytes from healthy controls. Nonetheless, these differences were not statistically significant. The immune hyperreactivity to type II collagen cannot explain the autoimmune mechanism of hearing losses. Humoral and cellular hyperreactivities to inner ear proteins different from type II collagen, could explain the autoimmune mechanism of deafness.

Adolescent↗
PubMed1999

Melatonin and other antioxidants prolong the postmortem activity of the outer hair cells of the organ of Corti: its relation to the type of death.

The outer hair cells of the organ of Corti transform sound into electrical signals, beginning the nervous auditive process. These cells produce acoustic emissions when working routinely, known as otoacoustic emissions. Otoacoustic emissions (OAEs) are recorded from the hearing duct through a probe which incorporates a sound source and a sensitive microphone. On the other hand, the cochlea produces oxygen-derived free radicals and nitric oxide, in addition, melatonin is present in the cochlea. The authors have studied the influence of melatonin or an antioxidant mixture (alpha-tocopherol acid succinate, ascorbic acid, glutathione, and N-acetylcysteine) on the postmortem activity of the outer hair cells of the organ of Corti of the rat, measuring distortion product otoacoustic emissions. Control rats showed postmortem distortion product otoacoustic emissions for about 2 min when sacrificed by decapitation, and for about 3 min when sacrificed by chloroform inhalation. Melatonin prolonged the postmortem activity 3.5 times when the animals were sacrificed by decapitation, and 7 times when animals were sacrificed by chloroform inhalation. Similar results were obtained with the antioxidant mixture. Results show that melatonin and other antioxidants have, in general, a protective role on the postmortem activity of the outer hair cells of the organ of Corti.

Animals↗
PubMed1999

Laparoscopic colorectal cancer resection: initial follow-up results.

An observational prospective cohort study was made to evaluate the results of laparoscopic colorectal cancer resection, in terms of recurrence and patient survival. Fifty consecutive patients were analyzed, subjected to abdominoperineal amputations of the rectum (n = 10), anterior rectal resection (n = 13), rectosigmoidectomy (n = 18), and other colectomies (right, left, segmentary) (n = 9). Mean follow-up was 21 months (maximum, 42 months). The tumors corresponded to stage I (TNM classification of the International Union Against Cancer) in 6 cases, stage II in 17, stage III in 18, and stage IV in 9 cases. Survival in stages I-IV was 100, 92, 79, and 18%, respectively, with a disease-free survival rate of 100, 70, and 49% in stages I-III, respectively. Recurrence was pelvic in four cases, with multiple growths, peritoneal carcinomatosis, lung metastases, and implantation in the port scar in one case each. To conclude, survival after a maximum follow-up period of 42 months was found to be acceptable and similar to the percentages reported in the literature for open surgery.

Aged↗
PubMed1998

Adenoidal and tonsillar lymphocyte subsets in AIDS children.

Tonsils and adenoids are secondary lymphoid organs exposed to the environment. The most important classifications of AIDS include the lymphocyte subsets of peripheral blood. We have studied the lymphocyte subsets in peripheral blood and secondary lymphoid organs in a control group of children suffering adenotonsillar pathology and in five children with AIDS and the same adenotonsillar pathology. The antigen surface markers were determined by flow cytometry in lymphocytes isolated from peripheral blood, and from tonsils and adenoids after tonsillectomy and adenoidectomy, in the control group and in children diagnosed with AIDS. The most important findings in tonsils and adenoids were a decrease of the total T lymphocytes, helper T lymphocytes and CD4/CD8 ratio; an increase of cytotoxic T lymphocytes and B lymphocytes, as well as a 200% increase in monocytes of AIDS-affected children. These observations show the value of analyzing the lymphocyte subsets of the tonsils and adenoids of AIDS-affected children, and establishing an earlier relation to clinical symptoms.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Melatonin restores and enhances the human type B tonsillar lymphocyte subset in recurrent acute tonsillitis.

Tonsils have a privileged situation in the immune system in that they are in touch with the environment. Melatonin is a hormone that is influenced by the circadian environmental variations of dark-light and is a modulator of the immune system. We have studied a group of thirty five children with recurrent acute tonsillitis that were submitted for tonsillectomy. Tonsillar lymphocyte subsets were determined before and after culture through flow cytometry in a tonsillar mononuclear suspension. After the culture, the lymphocyte subsets of type B suffered a decrease that was restored in the presence of melatonin or phytohemaglutinin, and even increased above the values of the control when the culture was accomplished in the presence of both substances. This process was specific for B cells, no occurrence for T lymphocytes or natural killer cells. Melatonin is found in the crossroads of the interaction of the microorganisms, pollens or inert substances with the tonsillar lymphocytes in the production of the immune defences. Further study is required on tonsillar pathology to explain its physiopathology and its possible therapeutic role.

Acute Disease↗
PubMed1998

Prevention of postoperative pulmonary complications through respiratory rehabilitation: a controlled clinical study.

OBJECTIVE: To investigate the efficacy of respiratory rehabilitation in preventing postoperative pulmonary complications (PPC) and to define which patients can benefit. DESIGN: A randomized clinical trial. SETTING: A public hospital. PATIENTS: Eighty-one patients who had upper abdominal surgery were distributed into two homogeneous groups: control (n = 41) and rehabilitation (n = 40). INTERVENTION: Breathing exercises in the rehabilitation group. MAIN OUTCOME MEASURES: Preoperative and postoperative clinical evaluation, spirometry, arterial gasometry, and simple chest X-rays. RESULTS: The incidence of PPC was 7.5% in the rehabilitation group and 19.5% in the control group; the control group also had more radiologic alterations (p = .01). Stratified PPC analysis did not reveal significant differences between groups. However, high- and moderate-risk patients in the rehabilitation group had fewer PPC. Multivariate analysis showed a greater PPC risk associated with pulmonary history (p = .02) and duration of surgery longer than 120 min (p = .03), while rehabilitation exerted a protective effect (p = .06). Significant postoperative decreases in pulmonary volumes and arterial gas values were recorded in both groups, without significant differences. CONCLUSIONS: Respiratory rehabilitation protects against PPC and is more effective in moderate- and high-risk patients, but does not affect surgery-induced functional alterations.

Adolescent↗
PubMed1998

Tonsillar lymphocyte subsets in recurrent acute tonsillitis and tonsillar hypertrophy.

Recurrent acute tonsillitis is usually produced directly by micro-organisms, mainly beta-hemolytic streptococcus. Idiopathic tonsillar hypertrophy is presented without infection history and usually leads to obstructive sleep apnea. We have measured lymphocyte subsets in tonsillar cellular suspensions of infectious and obstructive tonsillar pathology by flow cytometry. Comparing with peripheral blood, the CD4+/CD8+ ratio for tonsillar pathology varies from 4.0 to 5.0 while in peripheral blood the ratio was 1.3. In tonsils the ratio of B lymphocytes/T lymphocytes is 1.6, being 0.3 in peripheral blood, cytotoxic T lymphocytes represent 8% in tonsils and 29% in peripheral blood, virgin or nonstimulated T lymphocytes (CD4+ CD62L+) consist of 3% in tonsils and 16% in peripheral blood. The immature B lymphocytes (CD20+ CD5+) represent 23% in tonsils and 12% in peripheral blood. In regards to NK cells (CD3- CD16+), 1% was found in tonsils and 11% in peripheral blood. In tonsils B lymphocytes and a low proportion of cytotoxic T lymphocytes predominate, in comparison to peripheral blood, with a CD4+/CD8+ ratio four times greater than tonsils. We have found in tonsils a significant increase of T cells (CD3+ and TCR alpha+ beta+) in infectious processes in comparison to obstructive pathology.

Acute Disease↗
PubMed1998

The production of free oxygen radicals and nitric oxide in the rat cochlea.

Rat cochleas were analysed for free oxygen radicals (FOR) and nitric oxide (NO) production by the chemiluminescent oxidation of luminol. 4Beta-phorbol-12beta-myristate-13alpha-acetate (PMA), a well-known agonist of protein kinase C, induced the release of FOR after a time lag close to 30 s and reverted to basal values in approximately 10 min. Sphingosine inhibited by nearly 50% the response to PMA, whereas staurosporine caused an inhibition of 100%. The incubation of rat cochleas with 0.5 mM arginine potentiated the chemiluminescent reaction induced by PMA causing an additional oxidation of luminol that was inhibited by the NO synthase inhibitor N-methyl-arginine (NMA). Our results show for the first time the presence in the cochlea of cell populations producing FOR and NO and the real time production following cell activation. This procedure may help to explain the mechanisms involved in ototoxicity, as in the case of streptomycin and gentamicin that enhanced PMA-dependent production of FOR and NO.

Animals↗
PubMed1998

Pulmonary function and complications after laparoscopic cholecystectomy.

OBJECTIVE: To investigate the impairment of pulmonary function and complications after laparoscopic compared with open cholecystectomy through an upper midline incision. DESIGN: Prospective randomised trial. SETTING: Teaching hospital, Spain. SUBJECTS: 40 patients, 20 in each group. INTERVENTIONS: Clinical examination, spirometry, arterial blood gas analysis, and chest radiographs before and after operation. RESULTS: 48 hours postoperatively FVC and FEV1 had decreased to 56.7% and 53%, respectively, in the patients who had had open cholecystectomy, compared with 85.3% and 84.8% in the laparoscopic group (p < 0.0001). The mean (SD) postoperative percentage reductions in both PaO2 (86.1 (11.1) compared with 98.3 (11.3)) and SatO2 (98.6 (1.3) compared with 100 (1.5)) were also greater in the open group (p < 0.005 in both cases). CONCLUSIONS: Laparoscopic cholecystectomy causes less impairment of lung function than cholecystectomy through an upper midline incision.

Cholecystectomy↗
PubMed1997

Melatonin induces hyporeactivity caused by type II collagen in peripheral blood lymphocytes from patients with autoimmune hearing losses.

We have studied the behavior of peripheral blood lymphocytes in healthy controls and in patients with various hearing losses. These hearing losses were of an autoimmune origin in which type II collagen and melatonin were either present or absent, activated or not with concanavalin A (Con A). In patients with autoimmune hearing losses, the results showed lymphocytes that displayed hyporeactivity to type II collagen in terms of their proliferative activity in the presence of Con A. The hyporeactivity is specially relevant in those cells which are melatonin incubated. When different nosologic entities were studied, we observed similar lymphocyte hyporeactivity to type II collagen in bilateral sensorineural hearing loss, Ménière's disease and otosclerosis. We conclude that in the lymphocytes of patients with autoimmune hearing losses, there is hyporeactivity to type II collagen when compared to the hyporeactivity of lymphocytes in control groups. This hyporeactivity is revealed when the lymphocytes are activated in the presence of melatonin.

Adolescent↗
PubMed1997

Presence of the pineal hormone melatonin in rat cochlea: its variations with lighting conditions.

Within the normal inner ear, there are elements that belong to the immune system. Different inner ear disorders can be explained by autoimmune mechanisms, affecting both humoral and cellular immunity. Melatonin, the principal hormone of the pineal gland, modulates the immune system and extensively participates in the autoimmune processes related to type II collagen. Therefore, we have studied the presence of melatonin in rat cochlea, proving that its concentrations change depending on lighting conditions. Rats show high levels when confined to darkness and low levels when subject to continuous light exposure. The results correlate with the concentration of melatonin in peripheral circulation. Further experimental and clinical studies are necessary to clarify the role and the possible therapeutic applications of melatonin.

Animals↗
PubMed1997

Calcium supplementation and the risk of preeclampsia in Ecuadorian pregnant teenagers.

OBJECTIVE: To determine whether increased calcium intake (2 g/day) in pregnancy is effective in reducing the risk of preeclampsia in pregnant teenagers. METHODS: The present study was a prospective, randomized, double-blind, controlled clinical trial. Two hundred sixty teenaged pregnant girls attending the Hospital Gíneco-Obstétrico Isidro Ayora in Quito, Ecuador, were included. Selection criteria were age less than 17.5 years, nulliparity, first prenatal visit before 20 weeks' gestation, and residency in Quito (2800-m altitude). We used a table of random numbers to assign 125 girls to receive 2000 mg of elemental calcium daily, beginning at 20 weeks of gestation and continuing until delivery; 135 women in the control group received a placebo. Blood pressure (BP) was measured twice every 4 weeks until delivery and at 48 hours after delivery. The diagnosis of preeclampsia was defined as BP greater than 140/90 mmHg on at least two occasions more than 6 hours apart and proteinuria greater than 30 mg/dL (over one cross by dipstick on two occasions 4-24 hours apart). RESULTS: The average daily calcium intake in this population was approximately 51% of the Recommended Dietary Allowance. Calcium supplementation was associated with a significantly decreased risk of preeclampsia (risk reduction 12.35%; P < .001), with 3.2% (n = 4) developing preeclampsia in the treatment group versus 15.5% (n = 21) in the placebo group. Moreover, calcium supplementation led to a reduction in systolic BP of 9.1 mmHg and in diastolic BP of 6.0 mmHg. CONCLUSION: These results suggest that calcium supplementation during pregnancy in populations with low calcium intake is a safe, effective, and inexpensive preventive measure that significantly reduces the risk of preeclampsia.

Adolescent↗
PubMed1996

Analysis and Modeling of Time-Dose-Mortality of Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria (Orthoptera: Acrididae) from Beauveria, Metarhizium, and Paecilomyces Isolates from Madagascar

A complementary log-log (CLL) model was used to model time-dose-mortality relationships from bioassay tests of 26 fungal isolates mostly from Madagascar, Africa, against three acridid species, all referred to here as "grasshoppers." The fungal pathogens included 15 isolates of Beauveria bassiana, 9 isolates of Metarhizium flavoviridae, and 2 isolates of Paecilomyces spp. Grasshopper species tested included Melanoplus sanguinipes, Locusta migratoria migratorioides, and Schistocerca gregaria. The scaled deviance, mean deviance, Pearson X2 statistic, Hosmer-Lemeshow (H-L) C statistic, and three-dimensional time-dose-mortality graphs were used to assess extra-binomial variation, data points that were potential outliers, conformance of the scaled deviance statistic and Pearson's X2 statistic to a chi2 distribution, and the fit of the CLL model. The H-L C statistic also was found to be useful in showing the goodness of fit of the CLL model for the fungal isolates prior to modeling the extra-binomial variation. After the extra-binomial variation was modeled using Williams' method, the slope from maximum likelihood estimation, modified log(LD50) estimates (which were corrected for background mortality using the CLL model), a dynamic ranking of the log(LD50) values over time, and a three-dimensional plot of time, dose, and mortality of the three grasshopper species were used to evaluate the effectiveness of the fungal isolates. In general, the CLL model provided a rather poor fit of the fungal isolates which had a large number of replicate trials in the bioassay tests (i.e., a large sample size) due to extra-binomial variation. The CLL model provided an excellent fit of the time-dose-mortality relationships of such isolates after the extra-binomial variation was modeled and included in the CLL model. Metarhizium isolates MFV and SP5 were found to be the most virulent isolates tested against M. sanguinipes, followed by Metarhizium isolates: SP8, SP7, SP9, SP6, and SP1, and Beauveria isolate S33B. Metarhizium isolates SP3, SP5, SP6, and SP9, and Beauveria isolates SP11, SP12, SP13, and SP16 showed higher levels of virulence against L. migratoria migratorioides over more of the time periods tested than the other pathogen isolates examined. Metarhizium isolates SP9 and SP5 were the most effective isolates tested against S. gregaria. In general, the Metarhizium isolates were more virulent against the grasshoppers than the Beauveria isolates, which were more virulent than the Paecilomyces isolates. The CLL model was found to be very useful in describing grasshopper mortality as a function of time and dose. This approach combined with model and fungal isolate assessment statistics will be helpful for determining which pathogen isolates have the greatest potential for controlling grasshoppers and other pests in the future.

Journal Article↗
PubMed1996

Clinical manifestations and molecular epidemiology of five cases of diarrhoea in children associated with Vibrio metschnikovii in Arequipa, Peru.

In April 1994, Vibrio metschnikovii was isolated from five infants with watery diarrhoea in Arequipa, Peru, as part of a passive cholera surveillance system. The children ranged in age from 11 to 20 months and had acute diarrhoea, with two cases showing moderate dehydration. Two children also had traces of blood in liquid stool. The children were seen at two different hospitals, and no evidence of a common source of infection was found. No additional V. metschnikovii isolates were identified in the remaining surveillance period that covered the rest of 1994 and 1995. However, stool samples were not screened for enteric pathogens other than vibrios. V. metschnikovii strains isolated from stool samples produced opaque and translucent colonies on agar plates, suggesting capsular material. All isolates were resistant to ampicillin, erythromycin and streptomycin. Plasmid analysis revealed a common 200-kb plasmid in isolates from all cases and an additional 2.7-kb plasmid in three of the isolates. Ribotyping of each isolate after restriction with BglI and HindIII endonucleases demonstrated identical ribotyping patterns. The cases reported suggest that V. metschnikovii may be associated with diarrhoea in man by mechanisms so far unknown.

Acute Disease↗
PubMed1996

Laparoscopic treatment of esophageal achalasia.

An observational cohort study evaluated the initial results of using laparoscopic-approach cardioesophageal myotomy with Dor-type anterior fundoplicature for esophageal achalasia. The study involved our first 12 patients: five men and seven women whose median age was 51 years. Esophageal motility was vigorous in four patients; the other eight had aperistalsis. Conversion to laparotomy was required in one case. No postoperative mortality occurred. Postoperative complications included one left subdiaphragmatic abscess secondary to perforation of the esophageal mucosa, which was sutured. Median postoperative hospital stay was 5 days (confidence interval, 4.7-6.7 days). Symptom relief (disappearance of dysphagia) was recorded in 10 cases; relief with partial persistence of dysphagia was observed in the remaining two patients, who were treated by postoperative dilatation. As to the postoperative manometric results, the median basal pressure of the lower esophageal sphincter was reduced from 26.3 mm Hg preoperatively to 15.5 mm Hg postoperatively, with a tendency toward statistical significance (p = 0.08); the median esophageal isotopic retention after 15 min decreased from 60% preoperatively to 24.5% after surgery, with a tendency toward statistical significance (p = 0.07). Cardiomyotomy with Dor fundoplicature through a laparoscopic approach seems effective in treating esophageal achalasia.

Esophageal Achalasia↗