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Biomedical subjects

A Estévez

Publications and source records attributed to A Estévez.

13 recordsLinked to original sources
PubMed2004

Interleukin-1beta up-regulates nitrite production: effects on ovarian function.

We have previously reported that Interleukin-1beta (IL-1beta) affects ovarian function in the rat, modulating prostaglandin and progesterone (P) production. As IL-1beta effects were associated to nitric oxide (NO) synthesis, in the present work we have further examined the role of ovarian NOS-system, in IL-1beta antisteroidogenic action. Mid-luteal explants from rats were incubated for 4 h in the presence of IL-1beta (1-35 ng/ml)-alone or in combination with NOS-inhibitors-and then assayed for P and nitrite production. IL-1beta treatment reduced P levels in a dose-dependent manner, returning to basal levels at 35 ng/ml. This reduction in steroid synthesis was paralleled by a dose-dependent increase in nitrite levels, reaching a maximum at 25 ng/ml but without effect at 35 ng/ml. L-Arginine (1 and 2 mM) was able to mimic IL-1beta actions and the NOS blocker L-Nitro-Arginin-Methyl Ester reverted these effects. Moreover, the selective iNOS inhibitor, 1400 W, completely abolished IL-1beta antisteroidogenic effect, therefore confirming the dependence of IL-1beta action upon iNOS activation. Finally, IL-1beta did not affect eNOS expression but up-regulated iNOS mRNA and protein levels. Our results suggest an interaction between IL-1beta and the NOS-system. Thus, we may conclude that in the rat iNOS-derived NO production, induced by IL-1beta, affects ovarian P biosynthesis and hence NO may be a major effector molecule of ovarian IL-1 system.

Animals↗
PubMed2003

[Headache caused by cerebral angiopathy during labor with epidural analgesia].

A 29-year-old woman presented projectile vomiting followed by frontal headache, immediately upon receiving epidural analgesia for labor. The clinical picture persisted until expulsion. Although no leaking of spinal fluid into the needle or epidural catheter had been observed, post-dural puncture headache was diagnosed. The postpartum persistence of symptoms and the patient's generally worsening condition indicated the need for more thorough physical examination, which revealed signs of neurological involvement. Those findings and imaging studies (computed tomography of the brain, transcranial Doppler and magnetic resonance angiography) established a final diagnosis of postpartum cerebral angiopathy. Although epidural analgesia is increasingly requested by women entering labor, it is not a risk-free procedure. We describe a relatively unknown clinical entity, postpartum cerebral angiopathy, that developed during epidural analgesia for labor and that was initially believed to be a complication of the analgesic technique.

Adult↗
PubMed2000

[Licensure in the practice of the medical profession in Chile: experience of the Re-valuation Committee of the Medical School of the University of Chile period 1984-1999].

We report the experience of the re-valuation committee of the University of Chile Medical School, in the period 1984-1999. This experience is relevant to the licensing processes in Latin America. We report the political, legal and regulatory backup and the academic criteria used to establish different evaluation methodologies. We also communicate the main results obtained. Factors such as the country and University conferring a title, nationality and length of service of the applicant, influence in the percentage of licensure examination approval. Some modifications to the licensure process should be incorporated but, the overall results obtained, fully justify the existence of this licensure committee.

Accreditation↗
PubMed1999

[Role of nitric oxide in the synthesis of prostaglandin F2 alpha and progesterone during luteolysis in the rat].

In the corpus luteum (CL) prostaglandin F2 alpha (PGF2 alpha) is a luteolytic agent. Nitric oxide (NO) is a messenger molecule capable of modulating diverse pathophysiological processes. Many of these functions are related with the female reproductive tract. The aim of the present study was to investigate the role of ovarian NO in PGF2 alpha production arid in progesterone synthesis during CL regression in the rat. By means of the intrabursa (i.b.) ovarian sac treatment of two competitive NO inhibitors, NG-monomethyl-L-arginine (L-NMMA; 1 mg/kg); NW-Nitro-L-arginine methyl ester (L-NAME, 3 mg/kg) and sodium nitroprusside (SNP, 0.05 mg/kg) as a NO generator we found that NO, produced by the ovarian tissue during the last days (days 8 and 9) of CL development, acted by increasing PGF2 alpha production in the ovary and diminishing seric progesterone levels leading to CL involution. We also postulated a positive feedback mechanism between PGF2 alpha and NO, to ensure luteal regression. Thus, we injected intraperitoneally (i.p.) a luteolytic dose (3 micrograms/kg) of a synthetic PGF2 alpha during the mid and late phase of CL development. The ovarian activity was evaluated. The results confirmed our hypothesis; we did not see any effect in mid-stage of CL development, while at a late stage enhancement of ovarian NOs activity was observed in PGF2 alpha-infected animals.

Animals↗
PubMed1998

[Accreditation professional degrees and teaching institutions: the case of Chile].

Accreditation has acquired special relevance for the habilitation of professional practice, considering the proliferation of teaching institutions, the variety of training programs and the increasing amount of professionals requiring accreditation or revalidation of their titles. The internationalization of professional activities requires global and uniform accreditation procedures to avoid inequalities in evaluation of different professionals coming from abroad or from Chile. In the scope of medical practice, these concepts acquire special relevance, considering the appearance of new medical schools in the last decade and the increasing number of foreign physicians that need to revalidate their titles. In the period between January 1996 and September 1997, 192 foreign physicians applied to revalidate their titles and only 55 were approved. Therefore, the establishment of and effective evaluation system will correct deficiencies in the accreditation process and will promote the revision of training programs and the progress of teaching institutions. The organisms that will require to be accredited must be confident that this action will improve the quality of Chilean professional training.

Accreditation↗
PubMed1997

[Infectious endocarditis: prognostic factors of mortality in 131 cases].

BACKGROUND: Global hospital mortality for infective endocarditis ranges from 13 to 40%. AIM: To compare clinical, microbiological, echocardiographic factors and complications between patients that died during an episode of infective endocarditis and those who survived. PATIENTS AND METHODS: We followed during their hospital stay, 129 patients, aged 14 to 74 years old, who had 131 episodes of infective endocarditis. Clinical assessment, echocardiography and microbiological study was done to all patients. Surgical indications were those derived from complications. RESULTS: Thirty three patients died during hospital stay (25.2%). There were no differences between survivors and deceased patients in the lapse between onset of symptoms and hospital admission, presence of fever, dyspnea or heart murmurs. Skin and mucosal septic manifestations occurred with higher frequency in deceased patients (57.1 and 24.3% respectively). Blood cultures were positive in 55% in survivors and 48% in those who died. The most frequent infecting organisms were staphilococci and streptococci. Vegetations were found with greater frequency in aortic position in both groups of patients. Deceased patients had a higher frequency of cardiac failure (84 and 65% respectively) and embolic episodes (77 and 46% respectively) than survivors. Antimicrobial treatment was successful in 94% of survivors and 15% of those who died. Forty percent of survivors and 54% of deceased patients were subjected to surgical procedures. CONCLUSIONS: The most important predictor of hospital mortality in this series of patients with infective endocarditis was antimicrobial treatment failure.

Adolescent↗
PubMed1993

[Infective endocarditis: clinical aspects and necropsy study in 20 cases].

Aiming to know the principal anatomo-pathological findings in patients that died with a diagnosis of infective endocarditis, the clinical histories and necropsy protocols of such patients that died between 1984 and 1989 were reviewed. Twenty patients (11 male) aged 43.2 +/- 16.1 years were studied. In nine, the endocarditis was subacute, and 80% had a history of valvular or congenital heart disease. The principal clinical complication was sepsis followed by neurological, nephrological and cardiac complications. The necropsy disclosed cardiac, nephrological and abdominal lesions in 100, 80 and 65% of patients respectively. In 65% of necropsies, neurological injuries were found (cerebral edema in 7 patients and hemorrhagic complications in 11). It is concluded that extra cardiac lesions are frequent in patients dying with a diagnosis of infective endocarditis.

Adolescent↗
PubMed1991

[Physician-patient communication and health education].

The aim of the present study was to analyze the content in health education of the patient-physician interview. The study was observational and descriptive. The target population were the patients attending the general practices of the Social Security clinics. With permission of patients and physicians, 53 visits of two general practitioners were recorded on tape. 48 interviews were analyzed with definition of activities (asking, answering, discussing, etc.) and contents (health problems, treatment, health education, etc.). Health education was 10% of the contents, and it was associated with the physician's activity of commenting/instructing and with the patient's activity of commenting/asking.

Interviews as Topic↗
PubMed1989

[Infectious endocarditis: clinical and echocardiographic initial follow-up].

We analyzed the clinical and echocardiographic features of 24 patients with infective endocarditis followed for a mean of 20.2 month (range 3-84) after discharge. Mean age was 38 years, male to female ratio was 2:1 and 87% of cases had a subacute clinical course; 17% of patients had late prosthetic endocarditis. Positive blood cultures were obtained in only 50% of patients. Vegetations were detected by echocardiography in 88%, 66% of them located at the aortic valve. Heart failure (62%) was the main complication, leading to valve replacement in 4 patients. Four patients died during follow up, 3 males due to heart failure and a female from systemic emboli. Twenty patients survive at the end of follow up (84%), 50% of them in FC I or II, 40% in FC III or IV (2 lost to follow up). Eleven patients had a late echocardiogram at a mean of 12 months after discharge: 6 of them showed persistence of vegetations (55%).

Adult↗
PubMed1988

Cell surface glycoconjugates control the activity of the NADH-ascorbate free radical reductase of rat liver plasma membrane.

Plasma membrane isolated by two-phase partition from rat liver showed rates of ascorbate free radical reduction by NADH of 4-5 nmoles of oxidized NADH/min/mg protein. This activity was inhibited 80% by ConA and up to 97% by WGA and LFA lectins. NADH-ascorbate free radical reductase was also inhibited in rat liver plasma membranes preincubated with neuraminidase or trypsin, but no additional inhibition was observed in the presence of LFA after enzyme digestion. It appears that the integrity of glucan moieities of the cell surface glycoconjugates are necessary for the optimal function of this activity that could be considered as part of the transplasma membrane electron transport system.

Animals↗
PubMed1977

Serum immunoglobulin A changes in alcoholic patients.

1. Serum concentrations of immunoglobins IgA and IgG were determined in: Alcoholic men without liver damage (normal laboratory tests and only slight abnormalities in liver biopsy). 2. Patients at different stages of alcoholic liver disease. 3. Non alcoholic patients with liver disease. The serum IgA concentration was increased in all groups of alcoholics and this increase was related to the severity of liver damage. It was also raised in non alcoholic patients but both the degree of increase and the IgA/IgG ratio could be used to differentiate them. The increase in the serum IgA concentration in alcoholics without liver damage has not previously been proved and the reasons put forward for it in alcoholics are not valid for this group.

Alcoholism↗