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Biomedical subjects

A Ojeda

Publications and source records attributed to A Ojeda.

At least 19 recordsLinked to original sources
PubMed2005

[Intrapretosal schwannomas of facial nerve].

The aim of this study was to determine the factors that are important to the diagnosis and treatment of facial neuroma. The most common tumors of the peripheral nerves are the neurinomas; about 50% of them are found in the head and neck region. Among them, the most frequent is the VIII nerve tumor, while the facial neuroma is extremely rare. Neuromas can be intracraneal, intratemporal and extratemporal. The last one has a higher frequency. We present our experience in the intrapetrosal facial neuromas; usually showing different presentation symptoms wich is a characteristic of them. Retrospective study that was carried out at a private tertiary referral center. 3 patients were referred from other centers for otological surgery. One of them had symptoms of chronic otitis media, the second one was diagnosed of a glomus tumor and the last one showed a facial palsy. All the patients were operated on and then the facial nerve was repaired. Two patients had an end to end anastomosis, and in the other one we managed to keep the integrity of the facial nerve. The Hous -Brackmann facial grading scale was used. Two patients had grade II and the other grade III in this scale in the long-term follow up.

Cranial Nerve Neoplasms↗
PubMed2004

Clinical manifestations and hormonal profile of two women with Cushing's disease and mild deficiency of 21-hydroxylase.

The development of Cushing's disease among patients with deficiency of 21-hydroxylase has not been observed to date. The clinical manifestations and the hormonal profile of this exceptional association are herein described through the study of two cases. The first one was a 39-yr-old woman who had undergone non-curative transsphenoidal surgery for a pituitary-dependent Cushing's syndrome 12 yr before. She showed hypertension, central obesity, severe hirsutism, alopecia and hyperpigmentation. Urinary excretion of cortisol was normal, but ACTH levels were very high and hormonal dynamic studies (cortisol circadian rhythm, insulin-induced hypoglycemia and dexamethasone suppression tests) revealed the qualitative disturbances that characterize Cushing's disease. Serum concentrations of androstenedione, free testosterone and 17-hydroxyprogesterone were clearly increased. Reexamination of the tissue samples from previous surgery confirmed the presence of an ACTH-producing pituitary adenoma. CYP21 gene analysis found the splicing 655G mutation at intron 2 and the V281L mutation at exon 7. The second case was a 21-yr-old woman who was diagnosed with pituitary ACTH-dependent Cushing's syndrome according to unequivocal clinical and laboratory findings. However, hirsutism was particularly severe and both serum androgens and 17-hydroxyprogesterone were elevated. The patient was heterozygote for a large conversion of CYP21 gene. In these cases, the clinical and biochemical expression of Cushing's syndrome was determined by the different severity of 21-hydroxylase deficiency and the subsequent residual ability of adrenal cortex to synthesize cortisol.

Adenoma↗
PubMed2001

[Central diabetes insipidus as clinical presentation of a bronchogenic adenocarcinoma].

Metastatic tumors of the pituitary gland are uncommon. The majority of them are silent lesions incidentally discovered at autopsy. In contrast, the occurrence of symptomatic metastases is exceptional. Here we report the clinical and radiological findings of a 45 year-old woman with a metastatic lung adenocarcinoma who presented with diabetes insipidus and hypernatremic dehydration. There was no previous history of malignancy, and the pituitary metastases were responsible for the first manifestation of the disease. Clinical presentation, diagnosis and therapeutic management of patients with pituitary metastases are reviewed.

Adenocarcinoma↗
PubMed2000

[In vitro comparative activity of moxifloxacin and other antimicrobials against respiratory pathogens].

BACKGROUND: Respiratory pathogens are becoming increasingly resistant to antimicrobials. A new group of drugs, called respiratory quinolones have been synthesized to overcome this problem. AIM: To study the in vitro susceptibility of respiratory pathogens to old and new antimicrobials. MATERIALS AND METHODS: Forty five strains of S pneumoniae, 44 strains of H influenzae, 21 strains of M catarrhalis, 10 strains of methicillin susceptible S aureus and 20 strains of methicillin resistant S aureus were studied. All were isolated from community acquired respiratory infections during 1999. Minimal inhibitory concentrations of moxifloxacin, amoxicillin, amoxicillin/clavulanic acid, clarithromycin, azithromycin, ciprofloxacin and levofloxacin were determined using the Etest method. Beta-lactamase production by H influenzae and M catarrhalis was also studied. RESULTS: S pneumoniae strains were 100% susceptible to quinolones and cotrimoxazole, 2% were resistant to macrolides, 11% were resistant to amoxicillin/clavulanic acid and 47% were resistant to cefuroxime. H influenzae was 100% susceptible to quinolones, azithromycin and amoxicillin/clavulanic acid. There was a 53% resistance to cotrimoxazole, 21% to amoxicillin, 9% to clarithromycin and 7% to cefuroxime. M catarrahalis was 100% susceptible to quinolones and 100% resistant to amoxicillin, 5% resistant to macrolides, 14% resistant to amoxicillin/clavulanic acid, 20% to cefuroxime and 30% to cotrimoxazole. Methicillin susceptible S aureus was susceptible to all antimicrobials and methicillin resistant S aureus was resistant to all. CONCLUSIONS: Maxifloxacin and the new respiratory quinolones can be useful in the treatment of respiratory infections.

Adult↗
PubMed1999

Blood metabolites and their relationship with production variables in dual-purpose cows in Venezuela.

A survey was carried out on 79 lactating Bos taurus/indicus cross-bred cows on three dual-purpose cattle farms to measure the blood concentration of metabolites and to evaluate possible relationships with nutritional status and productive variables. A rotational grazing system on Star grass and other tropical pastures (10-12% CP in leaves) was used and 2-3 kg/cow/day of concentrate were fed on two farms. Restricted calf suckling was used in two herds. Average milk yield sold per farm was 6 kg/day/cow and body condition scores (BCS) were between 3.0 and 3.8 on a scale of one-to-five. On two farms, the average interval from calving to conception (ICC) was more than 145 days. Mean blood concentrations of albumin, globulin, urea, beta-hydroxybutyrate and phosphorus were generally within reference values, but a significant group of cows had low levels of albumin and urea and high levels of globulin. Packed cell volume (PCV) was below normal values, with anemia in 63% of cows during the second trimester of lactation, which was negatively correlated to milk yield. The high incidence of anemia could be related to factors such as hematophagic parasites, not evaluated in this study. ICC values were negatively related to albumin level and could be associated with protein deficiency in the diet or with disease, as globulin values were high in many cows. Based on these diagnoses, an experiment was carried out on one of the farms to evaluate the influence of supplementation with 0.5 kg/cow/day of fish meal. Total milk yield was not influenced by the fish meal and reproductive efficiency was high in the two supplemental treatments. It was shown that supplementation with undergraded protein is not required in these cows.

3-Hydroxybutyric Acid↗
PubMed1999

[Antimicrobial resistance of agents causing urinary tract infections in 11 Chilean hospitals. PRONARES project].

BACKGROUND: The computer program WHONET generates a common database to analyze local or general antimicrobial resistance of bacteria. A surveillance of agents causing urinary tract infections in Chile has been performed using this program. AIM: To report the results after 12 months of urinary tract infection agent surveillance. MATERIAL AND METHODS: Since November, 1997, a surveillance of in vitro antimicrobial resistance, using agar diffusion techniques, has been performed in 20 to 40 bacterial strains per month, isolated from 11 hospitals in the country. Results have been analyzed using WHONET program. RESULTS: In first 12 months, 3144 strains, 1625 coming from outpatients, have been studied. Seventy four percent of isolated strains were E coli, 19% were other enterobacteria, 4.1% were non fermenting bacilli and 2.1% were Gram (+) cocci. Sixty five percent of E coli strains were resistant to ampicillin, 11% to cefazolin, 2.5% to cefuroxime, 19% to ceftriaxone, 9% to ceftazidime, 4.2% to gentamicin 1.3% to amikacin, 5.6% to ciprofloxacin, 8.4% to grepafloxacin, 4.3% to nitrofurantoin and 43% to trimeproprim/sulphamethoxazole. Eighty two percent of other enterobacteria strains were resistant to ampicillin, 45.5% to cefazolin, 33.5% to cefuroxime, 26.6% to ceftriaxone, 21.5% to ceftazidime, 30.3% to gentamicin 17.2% to amikacin, 21% to ciprofloxacin, 16.3% to grepafloxacin, 48.2% to nitrofurantoin and 44.6% to trimeproprim/sulphamethoxazole. There were differences in betalactamic resistance among hospitals. CONCLUSIONS: Noteworthy is the high resistance rates to third generation cephalosporins, evidenced when the new cutoff values for E coli and Klebsiella spp are used. This national surveillance provides updated information on antimicrobial resistance of agents causing urinary tract infections.

Chile↗
PubMed1999

[Emergence of resistance to macrolides in Streptococcus pyogenes].

BACKGROUND: Diseases produced by Streptoccocus pyogenes are still a problem in Chile, as in the rest of the world. It exhibits in vitro susceptibility to different antimicrobials, but penicillin continues to be the treatment of choice. Alternative drugs have been developed for allergic patients, such as erythromycin, new macrolides and cephalosporins. Nevertheless, resistant strains are appearing due to the indiscriminate use of macrolides. AIM: To assess present antimicrobial susceptibility of S Pyogenes strains isolated from chilean patients. MATERIAL AND METHODS: The susceptibility to penicillin, macrolides, clindamycin, cephalotin and vancomycin of 153 S Pyogenes strains, obtained from different health centers of the Metropolitan Region and isolated between 1996 and 1998, was assessed using the Kirby-Bauer method. Agar dilution minimal inhibitory concentration was then determined to macrolide resistant strains. RESULTS: All strains were susceptible to penicillin. There was a 7.2% cross-resistance to macrolides. CONCLUSIONS: These results confirm that S Pyogenes resistance to macrolides has increased considerably in the Metropolitan Region of Chile during the last years.

Anti-Bacterial Agents↗
PubMed1995

Sorbitol-negative phenotype among enterohemorrhagic Escherichia coli strains of different serotypes and from different sources.

Enterohemorrhagic Escherichia coli (EHEC) strains detected with DNA probes (for virulence plasmid and Shiga-like toxins) from subjects with hemolytic-uremic syndrome (n = 19) or diarrhea (n = 41) or asymptomatic carriers (n = 29) were examined for sorbitol fermentability, as were enterotoxigenic (n = 40), enteropathogenic (n = 40), and enteroinvasive (n = 40) E. coli and urinary tract infection (n = 40) strains and normal flora E. coli strains (n = 40). Sorbitol negativity was common only in EHEC, particularly among strains from severe clinical infections. All 19 EHEC strains from patients with hemolytic-uremic syndrome, irrespective of O:H serotype or Shiga-like toxin genotype, were sorbitol negative.

Carrier State↗
PubMed1994

Relationship between pollinosis and fruit or vegetable sensitization.

The prevalence of vegetable sensitization in children with pollinosis (Group A; n = 48) and the prevalence of pollen sensitization in children with fruit or vegetable allergy (Group B; n = 42) were studied by means of prick-test and determination of serum specific IgE to several pollens, fruits and vegetables. Fifteen patients from Group A (31%) showed sensitivity to fruits and/or vegetables, but only three of them had any symptoms after ingestions. Twenty nine patients from Group B (69%) showed pollen sensitization, mainly to grass and Compositae pollen. An association was found between sensitivity to Compositae pollen and sensitivity to several fruits and vegetables (Compositae, Fagaceae, Brassica, Betulaceae and Leguminoseae).

Adolescent↗
PubMed1994

Lymphocytic hypophysitis causing hypopituitarism and diabetes insipidus, and associated with autoimmune thyroiditis, in a non-pregnant woman.

A 25 year old non-pregnant woman presented with a one-year history of amenorrhoea and polyuria. Three months before her admission, she had suffered lymphocytic meningitis. Hormonal studies revealed hypopituitarism and central diabetes insipidus, with associated primary autoimmune hypothyroidism. Computed tomographic scan and magnetic resonance imaging showed a pituitary mass with suprasellar extension and thickened stalk. Transsphenoidal surgery was performed and the histological study revealed fibrosis and diffuse lymphocytic infiltration with predominance of CD4 lymphocytes. This further case of lymphocytic hypophysitis was not related to pregnancy and produced diabetes insipidus, two uncommon associations. We discuss the features that can lead to a preoperative suspicion of this rare disorder.

Adult↗
PubMed1994

Dexamethasone-suppressible feminizing adrenal adenoma.

A 39 year old man presented with gynaecomastia, loss of libido and high blood pressure. Hormone studies revealed elevated plasma levels of oestradiol and its precursors, which increased in response to adrenocorticotrophic hormone and were reduced to normal levels with dexamethasone. Computed tomography disclosed a left adrenal mass and surgery was performed. The removed tumour weighed 84 g and the histological diagnosis was of adenoma. Nine years after surgery, he is asymptomatic, without hypertension, and radiological and or hormonal evidence of recurrence. We discuss the hormone profile in this case and the dynamics of steroid production by the tumour which, in contrast to the classical concept of tumour autonomy, showed dependence of oestradiol secretion on endogenous adrenocorticotrophic hormone.

Adenoma↗
PubMed1993

Dual genitotropic human papillomavirus infections in genital warts.

BACKGROUND AND METHODS: We have carried out a prospective study of dual genitotropic human papillomavirus (HPV) infections by means of two different DNA detection methods in biopsy specimens obtained from patients who were examined for genital warts at the STD clinic of the School of Medicine in Seville, between January 1990 and December 1991. RESULTS: 100 patients with a clinical diagnosis of condilomata acuminata were seen during the study period. DNA of the genitotropic HPV 6/11, 16/18 and 31/33/35 was detected by an in situ hybridisation method in 75 (77%) of the 98 evaluable samples; one of the genotypes tested in 59 (61%) samples, and two or more genotypes tested in the remaining 16 (15%) samples. In 21 (98%) of the 23 negative samples by in situ hybridisation, we were able to detect DNA of genital HPV using a polymerase chain reaction amplification method (PCR). Among the 34 samples where PCR was applied we confirmed the presence of two different HPV genotypes in eight samples. CONCLUSIONS: The frequency of dual infections with human genitotropic papillomavirus in genital warts was 8%, although we believe that this rate should be higher as we have not used the PCR method in all of the samples.

Adolescent↗
PubMed1993

[Pathogenic potential of vibrio cholerae 01 isolated from the Mapocho river and Aguada ditch].

The pathogenic potential of 20 strains of Vibrio Cholerae 01 isolated from the Mapocho river and Aguada ditch in Santiago, Chile was studied using a rabbit intestinal loop biological model. The presence of cholera toxin (CT) was previously found by the detection of CT gene, ELISA and passive reserve agglutination in only one of these strains. After 24 h of intestinal loop inoculation, the 20 strains showed enterotoxic activity. In four of these strains the secretory reaction was particularly intense. In these same four strains, the presence of cholera toxin was detected after the passage through the animal model. Thus, the number of cholera toxin producing strains increased after the inoculation in intestinal loops. These results suggest that the enterotoxic activity of strains that do not produce CT is given by the new cholera toxin (NCT). It is concluded that most of the strains of Vibrio Cholerae isolated from Mapocho river and its affluents are producers of NCT toxin, that some strains recover the capacity to produce CT after colonization of intestinal loops of living organisms and that the additive effects of CT and NCT may explain the intense enterotoxic activity of the strains that produce CT.

Animals↗
PubMed1992

Six new cases of a caterpillar-induced bleeding syndrome.

We describe six new cases of a hemorrhagic diathesis induced by contact with Lonomia achelous caterpillars. Onset of clinical bleeding varied between a few hours and 10 days post-exposure. Laboratory coagulation tests showed prolonged PT, PTT and ThT; normal platelets and a marked decrease of fibrinogen, factor V, plasminogen and factor XIII (including its subunits A and S). Factors VII, II and alfa 2 anti-plasmin were variably affected. In addition, activation of the fibrinolytic system and the generation of a procoagulant effect could also be demonstrated. Two cases developed severe hemorrhagic diathesis and one of them died of a cerebral hemorrhage. Different aspects of this rare syndrome are discussed in relation to its complex physiopathology and the variability observed in all clinical and laboratory manifestations. Therapeutic recommendations and some possible hazards following replacement transfusions are also considered.

Adult↗
PubMed1992

Enterohemorrhagic Escherichia coli associated with hemolytic-uremic syndrome in Chilean children.

A clinicoepidemiological study was undertaken to determine if enterohemorrhagic Escherichia coli (EHEC) was associated with hemolytic-uremic syndrome (HUS) in children in Santiago, Valdivia, and Temuco, Chile. Prospective surveillance detected 20 hospitalized cases of HUS in children less than 4 years of age in these cities from March 1988 to March 1989. Each HUS patient was matched (by sex and age) with two control children (hospitalized elective-surgery patients). To detect EHEC, DNA from stool culture isolates of E. coli was detected by hybridization with biotin-labelled DNA probes specific for the EHEC virulence plasmid, Shiga-like toxin I (SLT-I) or SLT-II. Stool cultures from 6 of 20 cases (30%) and from 2 of 38 controls (5.3%) yielded EHEC (P = 0.0158). EHEC isolates from all HUS cases hybridized with the EHEC plasmid probe and with probes for SLT-I or -II (or both). The serogroups of the isolates included O157, O26, and O111. EHEC causes HUS in Chile, and the biotinylated gene probes are practical diagnostic tools for epidemiologic studies.

Bacterial Toxins↗
PubMed1991

Epidemiologic patterns of acute diarrhea and endemic Shigella infections in children in a poor periurban setting in Santiago, Chile.

To prepare a field site for evaluating preventive interventions against endemic shigellosis, the authors followed prospectively a cohort of 360 children (90 each of children aged 0-11, 12-23, 24-35, and 36-47 months) in Santa Julia, a low socioeconomic area in Santiago, Chile, from November 1986 through April 1989 with twice weekly household visits for diarrheal disease; infants replaced children who reached 60 months of age. Coprocultures on 2 consecutive days from children with diarrhea and from age-matched controls within the cohort were cultured for Shigella. Bacteriologic surveillance was also maintained in the health center and children's hospital serving Santa Julia. In this community, where all households had access to potable water (68% inside) and all but 3% had access to a toilet, but where there was marked crowding, the overall incidence of diarrheal disease in the cohort was low (2.26 episodes/12 child months of observation in children aged 0-11 months and 2.09 in those aged 12-23 months), yet Shigella infections were common. Shigella accounted for 10% of diarrheal episodes in the cohort (vs. 3.2% isolation rate in controls, p less than 0.0001). The incidence of shigellosis in children aged 12-47 months was 0.16 cases per 12 child months of observation; in the first 5 years of life, a child had a 67% chance of experiencing shigellosis. Shigella sonnei, Shigella flexneri 2a, and S. flexneri 6 caused greater than 79% of the infections. Shigella occurred more often in hospitalized cases of diarrhea than in age-matched cases detected in the health center or by household surveillance (p less than 0.0001). An initial episode of Shigella diarrhea did not diminish overall the risk of subsequent shigellosis but did confer 72% protection (p = 0.05) against illness due to the homologous serotype. The high rate of both S. sonnei and S. flexneri shigellosis in a population with a low background rate of diarrhea makes Santa Julia an appropriate site for assessing the efficacy and effectiveness of measures to reduce Shigella infections.

Acute Disease↗
PubMed1991

An A alpha Ser-434 to N-glycosylated Asn substitution in a dysfibrinogen, fibrinogen Caracas II, characterized by impaired fibrin gel formation.

We have identified a unique N-glycosylated Asn substitution for a Ser at position 434 of the A alpha chain of an abnormal fibrinogen designated fibrinogen Caracas II. This dysfibrinogen was characterized by impaired fibrin monomer aggregation. Since there were 4 Thr residues immediately following the mutation, a new Asn-X-Thr/Ser-type consensus sequence, Asn-Thr-Thr arose for N-glycosylation of the Asn. The extra oligosaccharide was found to consist mainly of a disialylated biantennary structure comprising 81.9%, while a neutral and a monosialylated biantennary oligosaccharide represented only 3.6% and 14.5%, respectively. The mutation resides in the carboxyl-terminal region of the A alpha chain, which could fold back to form an extra small globular region located near the central region of the molecule (Erickson, H.P., and Fowler, W.E. (1983) Ann. N. Y. Acad. Sci. 408, 146-163; Weisel, H.P., Stauffacher, C.V., Bullitt, E., and Cohen, C. (1985) Science 230, 3124-3133). Therefore, the participation of this region, referred to as an additional central domain or an alpha domain, in fibrin gel formation is strongly implicated.

Amino Acids↗