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Biomedical subjects

R Armas

Publications and source records attributed to R Armas.

At least 19 recordsLinked to original sources
PubMed2006

Association analyses of the neuregulin 1 gene with schizophrenia and manic psychosis in a Hispanic population.

OBJECTIVE: This study used the population of the Central Valley of Costa Rica (CVCR) and phenotyping strategies alternative to DSMIV classifications to investigate the association of neuregulin 1 with schizophrenia. METHOD: Using 134 family trios with a history of psychosis, we genotyped six of the seven markers originally identified to be associated with schizophrenia in Iceland. RESULTS: The neuregulin Icelandic haplotype was not associated with schizophrenia in the CVCR population. However, a novel haplotype was found to be overrepresented in subjects with functional psychosis (global P-value > 0.05). Stratification of the sample by history of mania suggests that this haplotype may be preferentially over-transmitted to persons with a history of manic psychosis. CONCLUSION: These results suggest that the neuregulin 1 gene is unlikely to play a major role in predisposing to schizophrenia in the CVCR. Further studies in the CVCR and other Latin American populations should be performed in order to corroborate these findings.

Bipolar Disorder↗
PubMed1999

Clinical factors influencing the visual prognosis of the fellow eyes of normal tension glaucoma patients with unilateral field loss.

AIM: To investigate the influence of several clinical variables on the development of visual field loss in the "second eye" of patients with normal tension glaucoma (NTG) presenting with unilateral field loss. METHODS: Patients with NTG and unilateral field loss at presentation were selected from a cohort of 403 consecutive diagnoses of NTG. The state of the visual field "normal" or with a visual field defect was defined using the Advanced Glaucoma Intervention Study (AGIS) template. Where available, optic disc planimetry was carried out on stereo photographs taken at presentation. Measurements of the topography of each of these optic discs were compared with morphometric values from a group of normal subjects, allowing for differences in age and disc size. For each patient the percentage of the relative neuroretinal rim (NRR) area was calculated. The time taken to develop a visual field defect was related to clinical factors including age, sex, peak and mean diurnal intraocular pressure (IOP), refraction, relative NRR area, and the AGIS score of the fellow eye at presentation RESULTS: 54 patients were included in the study. The median (range) follow up time was 49.2 (11.1-116.7) months. 14 (26%) patients developed field loss in the eyes with an initially normal field. The estimate of the median time to field loss onset was 95.1 months. Field damage developed more rapidly in women and in patients with greater AGIS score in the contralateral eye at the beginning of follow up ((adjusted hazard ratio, HR (95% confidence interval, CI) 0.20 (0. 04; 0.93); 1.19 (1.02; 1.41) respectively)). Little evidence of any association was found between time to onset of field loss and each of age, refraction, and peak or mean diurnal IOP. Planimetric disc analysis was carried out in 33 (61%) patients. Of these 10 (30%) developed field loss in the eyes with initial normal field at a median follow up of 95.1 months. After adjustment for sex and AGIS, relative NRR area was found to be significantly related to the time of onset of field damage, the greater the reduction in relative NRR area, the shorter the time to visual field loss (HR 0.93 (0.89; 0. 99)). CONCLUSIONS: NTG patients with unilateral field loss are at high risk of developing field damage in the eyes with an initially normal visual field. In this study, the visual prognosis of the eye with the normal visual field at presentation was found to be influenced by the extent of the reduction in relative NRR area together with the severity of field damage in the contralateral eye at presentation.

Female↗
PubMed1998

[Acquired characteristics of porphyria cutanea tarda in patients infected with hepatitis C virus].

BACKGROUND: Porphyria cutanea tarda (PCT) is due to a partial defect of hepatic uroporphyrinogen decarboxylase (URO-D). In the hereditary form, both hepatic and erythrocytic enzymes are altered, whereas in the acquired form, only the hepatic enzyme fails. There is a high prevalence of hepatitis C virus infection in patients with PCT, specially in those without family history of the disease. AIM: To study erythrocytic URO-D activity in order to find out whether hepatitis C virus infection is associated to the acquired form of PCT or unveils an inactive hereditary form. PATIENTS AND METHODS: URO-D activity was measured in red blood cells of normal controls, hepatitis C virus carriers without symptoms of PCT and patients with PCT, with and without family history of the disease, with and without anti hepatitis C virus antibodies. RESULTS: URO-D activity was similar in normal controls, patients with chronic liver disease associated to hepatitis C virus, and in patients with PCT without family history of the disease with and without hepatitis C virus antibodies. URO-D activity was lower in patients with PCT and family history of the disease, with and without hepatitis C virus antibodies. CONCLUSIONS: PCT in patients with hepatitis C virus infection is due to an acquired alteration of hepatic URO-D. Hepatitis C virus does not modify erythrocytic URO-D.

Adult↗
PubMed1997

[Specialty certification for physicians with pre or postgraduate degree who studied abroad. Experience of the National Autonomous Commission for the Certification of Medical Specialties (CONACEM)].

BACKGROUND: The number of foreign or Chilean physicians with pre or postgraduate studies abroad, seems to be increasing. AIM: To report the experience of CONACEM in the certification of specialties for Chilean or foreign physicians that studied abroad. MATERIALS AND METHODS: The certification process for 90 physicians (38 Chilean and 52 foreign) with studies abroad is reported. Criteria for certification of specialties were the same used for physicians with studies in Chile and results were compared with those obtained by the latter. RESULTS: Physicians with studies abroad required additional evaluations with a greater frequency than local physicians, due to the fact that foreign training programs are not well known by CONACEM members. Eighty five percent of foreign physicians required those further evaluations, compared with 66.6% of all physicians certified by the commission. Fifty five percent of Chilean physicians with studies abroad did not accept this additional assessment. Applications for specialties of physicians with studies abroad, were rejected with a greater frequency than those of Chilean physicians (31% and 13%, respectively). CONCLUSIONS: Physicians with studies abroad applying for certification of medical specialties required more evaluations and were rejected with a greater frequency than Chilean physicians.

Certification↗
PubMed1997

[The care of the terminally ill patient].

Drs. Alejandro Goic (internist), Ramón Florenzano (psychiatrist), Bernardino Piñera (physician and Catholic Bishop), Sergio Valdés (internist) and Rodolfo Armas (internist) participated in a round table about the care of the terminally ill, during a Postgraduate Course organized by the Chilean Society of Gastroenterology. After a general introduction, participants discussed the psychological aspects of terminally ill patients, about the sense of death from a Christian anthropological perspective, the terminally ill in intensive care units and finally about the education of medical students in this frequently neglected aspect of medical practice.

Attitude to Death↗
PubMed1996

[Treatment of porphyria cutanea tarda with chloroquine and its effect on associated liver disease: retrospective analysis].

BACKGROUND: Chloroquine may improve cutaneous symptoms and liver disease manifestations in patients with porphyria cutanea tarda. AIM: To retrospectively analyze the effects of choloroquine in patients with porphyria cutanea tarda. PATIENTS AND METHODS: Five patients (one female), aged 45 to 65 years old, were studied. The duration of the disease ranged from 2 to 15 years. One patient was alcoholic and other was a hepatitis C virus carrier. All patients received chloroquine 125 mg twice weekly. Before, during and after treatment, cutaneous signs, serum bilirubin, hepatic enzymes and urine copro and uroporphyrin were assessed. Four patients were subjected to a liver biopsy before starting chloroquine. RESULTS: All patients had increased levels of urine porphyrins, four had abnormal serum liver enzymes. All liver biopsies showed variable hemosiderosis, two patients had a chronic active hepatitis (one with cirrhosis), one a chronic persistent hepatitis and one had mild rague alterations. During chloroquine treatment, cutaneous symptoms improved in all patients, transaminases and gamma glutamyl transferase decreased. In three, urine uroporphyrin increased initially and normalized afterwards. Choloroquine was well tolerated. CONCLUSIONS: Chloroquine improved cutaneous symptoms, urine uroporphyrin and serum liver enzyme levels in treated patients.

Aged↗
PubMed1994

[Hepatitis C virus infection in patients with porphyria].

Hepatitis C virus antibodies were studied in sera coming from 39 patients with porphyria (cutanea tarda in 17, variegate in 8, intermittent acute in 4, coproporphyria in 2 and protoporphyria in 8). Nine of 17 patients with porphyria cutanea tarda had positive antibodies, but none of the patients with other types of porphyria. All subjects with porphyria cutanea tarda had histological or laboratory liver abnormalities. There was no relationship between the presence of antibodies and frequency of alcoholism, diabetes, or carbohydrate intolerance. Family background of porphyria was significantly less frequent among patients with positive hepatitis C virus antibodies. In 13 patients, a liver biopsy was performed, always showing signs of chronic hepatitis, whose magnitude was higher in those with positive antibodies. It is concluded that, as reported previously, hepatitis C virus may be an activating factor for porphyria cutanea tarda or may potentiate its accompanying liver disease.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

[Porphyria cutanea tarda, chronic liver disease caused by the C virus and hepatocarcinoma. Clinical case].

We report a non alcoholic, Chinese, 65 years old male that presented in august, 1992 with painful hepatomegaly of rapid installation and malaise. Ultrasound examination revealed multiple substitution images, diagnosed histologically as hepatoma. Serum alpha fetoprotein was 6600 U/ml. Malaise increased and the patient died two months later. This patient had a porphyria cutanea tarda and a chronic hepatitis diagnosed 6 years before. He also had positive titers for hepatitis C virus antibodies. In patients with porphyria cutanea tarda, hepatoma frequency is 400 fold higher and hepatitis C virus infection is highly prevalent. Thus, the surveillance of these patients with periodic alpha feto protein determinations and abdominal ultrasound examinations is recommended, specially in those infected by hepatitis C virus.

Aged↗
PubMed1993

[Hepatitis C virus antibodies in chronic non-alcoholic liver disease].

The presence of hepatitis C virus antibodies was studied in 64 patients with non alcoholic liver disease and found in 11 (17%). The greater frequency of positive antibodies was found among patients with cryptogenetic liver disease, specially those without serum auto-antibodies (32%). The antibody was unusually found (0 to 11%) in non alcoholic liver diseases of other etiologies. It is concluded that hepatitis C virus chronic infections may be the etiology of an important number of non alcoholic chronic liver diseases.

Adult↗
PubMed1993

[Prevalence of hepatitis C virus antibodies in a hemodialysis unit].

The prevalence of hepatitis C antibody was studied using the EIA 2 Abbott assay in patients and staff of the San Juan de Dios Hospital Hemodialysis Unit. The antibody was detected in 29.8% of patients, no member of the staff had positive antibodies. Patients with a positive antibody had been on hemodialysis for a longer time than those with a negative test (53.3 +/- 18.8 vs 37.9 +/- 33.5 months respectively). No differences in the number of transfusions received were observed between patients with positive or negative antibodies. Hepatitis B surface antigen was detected in 2 patients, with negative hepatitis C virus antibody. No clinical evidence of liver disease was found among patients with positive antibodies.

Acute Kidney Injury↗
PubMed1993

[Rheumatoid arthritis. Therapeutic efficacy of methotrexate and its hepatotoxic effects].

The efficacy and toxicity (specially hepatic) of methotrexate in low doses (7.5 mg/week) was prospectively assessed in 21 patients with rheumatoid arthritis refractory to treatment with gold or penicillamine, during two years. Three patients were prematurely withdrawn from the protocol. A fast and significant improvement of RA was observed during the first six months, which tapered thereafter. Erythrocyte sedimentation rate decreased from 51.5 +/- 20.1 to 27.7 +/- 11.5 mm/h (p < 0.05). A rise in serum transaminases, always raising to less than twice the normal value, was observed in 75% of patients in some moment of the follow up. Hepatic scintigraphy did not show significant changes. Hepatic histological alterations were mild and no changes were observed after two years of treatment. The main secondary effects were moderate and transitory gastrointestinal and hematological disturbances. The prednisone dose was decreased from 6.8 +/- 2.6 to 4.8 +/- 1.9 mg/day at twelve months. There were no withdrawals due to drug toxicity. It is concluded that methotrexate proved to be efficacious in the treatment of rheumatoid arthritis refractory to conventional treatments. Its secondary effects, although frequent, were discrete and transitory and there were no changes in liver histology.

Adult↗
PubMed1993

[Prevention of digestive hemorrhage recurrence in hepatic cirrhosis with propranolol. A 4 years' follow-up study].

The aim of this study was to assess the effect of propranolol treatment on the recurrence of variceal bleeding and mortality in patients with hepatic cirrhosis. Fifty seven patients were studied; they were recruited within 15 days of an episode of variceal bleeding, assigned randomly to receive propranolol (n = 29) placebo (n = 28) and followed during 4 years. Three patients were lost from follow up and in 3 propranolol was discontinued due to secondary effects. Bleeding recurrence was less frequent in the treated patients (Kaplan Meier analysis p < 0.01). Ten patients on placebo and 1 receiving the active drug died. Life table analysis showed a significantly better survival in the group of patients treated with propranolol. It is concluded that propranolol decreases the recurrence of variceal bleeding and improves survival in patients with hepatic cirrhosis.

Adult↗
PubMed1992

[The hepatic porphyrias: experience with 105 cases].

Hepatic porphyria is a rare metabolic syndrome caused by abnormal enzyme activity in heme biosynthesis. Between 1974 and 1991; 105 patients have met criteria for diagnosis of hepatic porphyria based on typical clinical findings and/or laboratory abnormalities. According to type, 42% had porphyria cutanea tarda, 21% porphyria variegate, 15% protoporphyria, 6.7% acute intermittent porphyria, 6.7% coproporphyria and 1.9% porphyria due to porphobilinogen deficit. A proper classification was not established in 6.7% of patients. Porphyria cutanea tarda was more common in males (70%) and porphyria variegata, in females (90%). A family history of the disease was present in 33% of patients; 20% of patients were of European descent and 4% of Mapuche descent. Diagnosis was usually established in the third decade, somewhat later in porphyria cutanea tarda (45 years of age) and very early in protoporphyria. 10% of patients were asymptomatic and 29 patients developed at least one porphyric crisis. These were related to pregnancy in 6 patients, to hormone administration in 7, to antibiotics in 5. No cause was established in 21 cases. Severe crisis were successfully treated with Hematin. Venipuncture was used to treat 50% of patients with porphyria cutanea tarda with 95% success. Thus, hepatic porphyria is recognized with increasing frequency and can be treated successfully in most cases.

Adolescent↗
PubMed1991

[Experience of the National Autonomous Board for Certification of Medical Specialties].

After 6 years of operation of a National (autonomous) Board for Certification of Medical Specialists, the number, distribution and training of medical specialists is analyzed. Problems regarding significant differences in the quality of training and imbalance among different specialties are identified. The medical profession has expressed its confidence and feels supported by the activities of the Board. However, health care deliverers and users in general are expected to increase their support and consideration for the information provided by the Board, in order to fulfill the purpose for which it was established.

Chile↗
PubMed1981

The posterior cerebral radionuclide angiogram for the detection of carotid artery disease.

To determine the accuracy of the posterior cerebral radionuclide angiogram (CRAG) in the detection of carotid occlusive disease, a retrospective study of 186 patients who underwent both CRAG and contrast cerebral angiography within a period of 30 days was carried out. Asymmetry of neck activity was highly specific (97%) but insensitive (27%) for detection of carotid disease. When asymmetry of cerebral perfusion was also considered, the sensitivity rose to 61%, but the specificity fell to 77%. For the entire group, including carotid and intracerebral disease, the sensitivity of the posterior CRAG was 49% and the specificity 89%. From these data and a review of the literature, we conclude that the CRAG is too insensitive to be used as a screening test for carotid occlusive disease.

Arterial Occlusive Diseases↗
PubMed1979

A simple method of spleen imaging with 99mTc-labeled erythrocytes.

A simple technique of splenic localization with 99mTc-labeled red blood cells is described. A blood sample is obtained 30 minutes after administration of nonradioactive pyrophosphate. Pertechnetate is added to the sample and the blood is incubated for 35 minutes at 49 degrees C. One to two hours after reinjection, selective spleen imaging can be performed.

Child↗