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Biomedical subjects

M Quintana

Publications and source records attributed to M Quintana.

At least 19 recordsLinked to original sources
PubMed1997

Heart rate variability as a means of assessing prognosis after acute myocardial infarction. A 3-year follow-up study.

AIMS: The present study evaluated the prognostic value of heart rate variability after acute myocardial infarction in comparison with other known risk factors. The cut-off points that maximized the hazards ratio were also explored. PATIENTS AND METHODS: Heart rate variability was assessed with 24 h ambulatory electrocardiography in 74 patients with acute myocardial infarction, 4 +/- 2 days after hospital admission and in 24 healthy controls. Patients were followed for 36 +/- 15 months. RESULTS: During follow-up, 18 patients died, nine suffered a non-fatal infarction and 20 underwent revascularization procedures. Heart rate variability was higher in survivors than in non-survivors (P = 0.005). This difference was found at higher statistical levels when comparing non-survivors vs controls (P = 0.0002). A similar statistically significant difference was also found between survivors vs controls (P = 0.04). Patients suffering non-fatal infarction and cardiac events (defined as death, non-fatal infarction or revascularization) had a lower heart rate variability than those without (P = 0.03 and P = 0.03, respectively). With multivariate regression analysis, decreased heart rate variability independently predicted mortality and death or non-fatal infarction. The presence of a left ventricular ejection fraction < 40% and a history of systemic hypertension were, however, stronger predictors. The cut-off points that maximized the hazards ratio using the Cox model differed from those reported by others. CONCLUSION: Decreased heart rate variability independently predicted poor prognosis after myocardial infarction. However, the cut-off points that should be used in clinical practice are still a matter for further investigation.

Adult↗
PubMed1996

Antibodies to factor VIII in plasma of patients with hemophilia A and normal subjects.

Non-neutralizing factor VIII (FVIII) antibodies (FVIII-Ab) in hemophilia A may be associated with an abnormal clinical response to FVIII concentrates. Patients with FVIII inhibitors may develop noncoagulation FVIII-Ab after the induction of immunotolerance. Natural FVIII-Ab may be detected in the plasma of some healthy subjects. The aim of this study was to analyze the presence of FVIII-Ab in the plasma of 53 normal blood donors and 124 patients with hemophilia A (18 patients had a previous history of FVIII inhibitor, but only 12 had inhibitor at the moment this study was performed). FVIIII inhibitor was measured using the Bethesda method. FVIII-Ab were analyzed by a specific ELISA assay using purified FVIII from a monoclonal concentrate and a standard plasma containing 26 Bethesda units (BU) of FVIII inhibitor. Purified FVIII was used to coat wells of a microtiter plate and was incubated with dilutions of plasma to be tested. Bound human IgG FVIII-Ab were detected by incubation with polyclonal sheep anti.human IgG alkaline phosphatase conjugate, and the OD405 was quantitated. A linear fit was obtained (by plotting FVIII-Ab positivity [OD 405nm] versus BU titer) when serial dilutions of this standard inhibitor plasma, containing titers of 0.5 BU or higher, were used. Four different levels of FVIII-Ab positivity [OD 405nm] were distinguished in this assay: Negative levels (-) were obtained with dilutions of the standard inhibitor containing < 0.5 BU. Mild levels (+) were obtained with dilutions of 0.5-5 BU. Moderate levels (+2) were obtained for dilutions ranging from 5-25 BU. Maximum positivity (+3) was obtained for dilutions of titers > 25 BU. FVIII-Ab positivity was detected in eight of the normal subjects (15%): three were found to be moderately positive (+2) and five mildly positive (+). No inhibitory activity was detectable when whole plasma was used. All the hemophilic patients with a presence of FVIII inhibitor at the time of the study were found to be positive for FVIII-Ab. In addition, the level of positivity correlated with the corresponding BU. Four of the six patients who had a history of inhibitory were negative and two positive. Twenty additional patients (16.12%) in whom no inhibitory activity was detected were found to be positive for FVIII-Ab: 16 + and four +2. The mean age of patients with FVII-Ab positivity was significantly higher than that of patients of the FVIII-Ab negative group (p < 0.005). In conclusion, FVIII-Ab positivity in patients with hemophilia A was 17.7% higher than the level of positivity detected by an inhibitory assay. We propose that this method for FVIII-Ab analysis could be used for patients with hemophilia A, at least to complement the functional inhibitor assay. FVIII recovery or half-life should be assessed in patients who test positive for FVIII-Ab and who show no evidence of inhibitor.

Adolescent↗
PubMed1996

[Parainfectious transverse myelitis in an adolescent. Difficulties in the etiological diagnosis].

A diagnostic process in a 13 year-old boy with a parainfectious transverse myelitis is described. Its onset was acute, with L1-location level of lesion. After a mild improvement, a relapse happened 26 days later, with a D6 level and without subsequent recovery. It has not been found criteria for diagnosis of multiple sclerosis, nor data suggesting a vascular or ischaemic anomaly. Likewise, other causes and specific infections were rejected, being cataloguet as parainfectious etiology, due a previous viral infection before its onset.

Acute Disease↗
PubMed1995

Prognostic value of predischarge exercise stress echocardiography after acute myocardial infarction.

A predischarge exercise test was performed by 70 patients 7 +/- 4 days (mean +/- SD) after acute myocardial infarction (AMI) to determine the short- and long-term prognostic value of predischarge exercise stress echocardiography (Ex-Echo) compared with exercise stress electrocardiography (Ex-ECG). Two-dimensional echocardiograms were obtained at rest and immediately after exercise; a wall motion score index was obtained both at rest and immediately after exercise. Results of the Ex-Echo were positive in 27 patients (39%), whereas those of Ex-ECG were positive in 34 (49%). The wall motion index after exercise was lower in patients who died during follow-up (85 vs 98, p = 0.01) and in those with cardiac events, defined as death, nonfatal reinfarction, or revascularization (88 vs 98, p = 0.005). More patients with a positive Ex-Echo result had short-term cardiac events (within 2 weeks) than patients with a negative Ex-Echo (6 [22%] vs 2 [5%], p = 0.04). The same was true for long-term mortality (12 [44%] vs 3 [7%], p = 0.0002), reinfarctions (10 [37%] vs 4 [9%], p = 0.01), revascularization procedures (11 [41%] vs 7 [16%], p = 0.023), and cardiac events (22 [81%] vs 12 [28%], p < 0.0001). Survival time was shorter in patients with positive compared with negative Ex-Echo results (34% difference between groups, 95% confidence interval [CI] 10% to 58%, p = 0.002). The same applied for cumulative survival free from cardiac events (43%, p = 0.001, 95% CI 9% to 77%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Assessment and significance of ST-segment changes detected by ambulatory electrocardiography after acute myocardial infarction.

This study assessed the prognostic value of ST-segment changes detected by ambulatory electrocardiographic monitoring during the early in-hospital period after acute myocardial infarction. New methods for defining the ST-segment reference level and for measuring ST-segment elevation were used. ST-segment depression was defined as a change in ST level by > or = 0.1 mV 80 ms after the J point, elapsing > or = 1 minute. ST-segment elevation was defined as a deviation by > or = 0.15 mV, elapsing > or = 1 minute, and measured at the J point. An interval of > or = 2 minutes was required before another discrete episode was counted. Four ST-segment reference levels were automatically calculated: (1) "isoelectric," (2) "nearest to normal," (3) "24-hour median," and (4) "first-hour median." During a mean follow-up period of 3 years (mean 36 +/- 15 months), 47 cardiac events occurred in 38 patients: 18 deaths, 9 nonfatal reinfarctions, and 20 revascularization procedures. More deaths occurred in patients with than without ST elevation-24-hour median (22% vs 5%, p = 0.03), and in patients with than without ST depression-isoelectric (61% vs 32%, p = 0.02), and in patients with than without ST-depression-24-hour median (61% vs 23%, p = 0.003). "All cardiac events" (deaths, infarctions, or revascularization procedures) occurred more often in patients with than without ST depression-isoelectric (55% vs 22%, p = 0.003), and in patients with than without ST-depression-24-hour median (47% vs 17%, p = 0.004). Sensitivity, specificity, and accuracy of ST depression/elevation-24-hour median to assess mortality were 78%, 71%, and 73%, respectively.

Aged↗
PubMed1995

ST-segment depression on ambulatory electrocardiography in the early in-hospital period after acute myocardial infarction predicts early and late mortality: a short-term and a 3-year follow-up study.

A surveillance study was conducted to determine the in-hospital and long-term prognostic value of ST-segment depression assessed by ambulatory electrocardiographic monitoring (AEM) during the early in-hospital period after acute myocardial infarction (AMI). ST-segment depression (STD) was determined by computer analysis of 24-h ECG tapes as a horizontal or downsloping change in ST level by > 0.1 mV from the reference base line. The ST level was measured 80 ms after the J point of all normally conducted complexes for > or = 1 min. All computer-detected ST events were verified by one trained reader. Tapes corresponding to 74 patients were analyzed. In addition, 23 tapes corresponding to age- and gender-matched controls were also analyzed. Patients were divided into two groups: 22 patients (30%) showed STD (Group A), and 52 patients (70%) had no episode of STD (Group B). Among controls, 1 person (4%) showed STD. During the early follow-up period (14 +/- 11 days after hospital admission), cardiac events occurred in 11 patients [7 (32%) in Group A and 4(8%) in Group B, p < 0.01], including 6 cardiac death [5 (23%) in Group A and 1 (2%) in Group B, p < 0.01], 3 acute coronary artery bypass surgeries [2 (9%) in Group A and 1 (2%) in Group B, p = NS], and 2 nonfatal myocardial infractions (both in Group A, p = NS). During a mean follow-up period of 3 years (36 +/- 15 months), 18 patients died [10 (45%) in Group A and 8 (15%) in Group B, p = 0.01]. Eleven deaths were sudden [7 (32%) in Group A and 4 (8%) in Group B, p < 0.01]. Eighteen AMI occurred [11 (50%) in Group A and 7 (13%) in Group B, p < 0.005]. Twenty patients underwent revascularization procedures [7 (32%) in Group A and 13 (25%) in Group B, p = NS].(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnosis, Computer-Assisted↗
PubMed1995

Prognostic value of exercise stress testing versus ambulatory electrocardiography after acute myocardial infarction: a 3 year follow-up study.

BACKGROUND: The aim of this study was to evaluate the prognostic significance of myocardial ischemia detected by ambulatory ECG monitoring (AEM) and exercise stress testing (ExT) following acute myocardial infarction. METHODS: The prognostic value of AEM versus ExT was studied prospectively in 74 patients with a recent acute myocardial infarction. Myocardial ischemia was diagnosed by the presence of ST-segment depression occurring during AEM or ExT 4 +/- 2 and 7 +/- 4 days after hospital admission respectively. ST-segment depression during AEM was defined as a horizontal/downsloping depression of > or = 0.1 mV from the reference baseline, measured 80 ms after the J point, elapsing > or = 1 min. ST-segment depression at ExT was determined as > or = 1mm horizontal or downsloping ST-segment depression in at least two consecutive ECG leads. RESULTS: Twenty-two patients (30%) showed ST-segment depression during AEM and 34 (49%) on ExT. During a mean follow-up period of 3 years (36 +/- 15 months), 10 patients (45%) with ST-segment depression on AEM died compared with eight (15%) without; 12 patients (35%) with ST-segment depression on ExT died versus three (8%) without. Death or reinfarction occurred in 13 patients (59%) with ST-segment depression on AEM versus nine (17%) without, and in 13 patients (38%) with ST-segment depression on ExT compared with six (17%) without. Revascularization procedures were similar in patients with or without ST-segment depression during AEM and ExT. Cardiac events defined as death, nonfatal reinfarction or revascularization, occurred in 18 patients (82%) with ST-segment depression on AEM versus 20 (38%) without, and in 23 patients (68%) with ST-segment depression on ExT versus 11 (31%) without. Survival analysis using Kaplan-Meier curves showed that patients showing no ST-segment depression with either technique had longer survival times than did patients showing ST-segment depression on either AEM or ExT, or showing ST-segment depression with both techniques. This was also true when analyzing the cumulative survival rate until the occurrence of any endpoint. With multivariate regression analysis, ST-segment depression on AEM was the variable most strongly predictive of mortality, followed by ST-segment depression on ExT, hypertension, and diabetes. CONCLUSIONS: These findings illustrate the ability AEM and Ext independently to predict long-term cardiac mortality and morbidity rates in patients recovering from acute myocardial infarction. The combined use of these techniques is useful for detecting patients at high risk after acute myocardial infarction.

Electrocardiography, Ambulatory↗
PubMed1990

[Mortality by crushing in domestic pigs: study of the causes and their relationship to the time and the month of the year in the climatic conditions of Cuba].

In the course of 3 years a complex of 25,000 pigs were investigated once per week for the dead among the 398 sucking piglets, and in the case of losses due to crushing to death the type of lesions and the connection with diseases was investigated. Of the piglets investigated, 88 were crushed to death (21.2%), among them 65 (73.8%) diseased--mainly infected by coli bacilli (60 = 68.2%)--and 23 (5.8%) healthy animals. The losses due to crushing to death were highest in January and differed from all other months of the year (p less than 0.05). Another peak of losses in July was only significant (p less than 0.05) as compared with the values of April and November. January and July also exhibited the highest proportion of coli-infected piglets. The most frequent lesions were edema and cyanosis of the skin, of the mucous membrane, and the hypodermic tissue, haemothorax and haemoperitonaeum, liver cracks, lung cracks, kidney cracks, stomach cracks, large intestine cracks, and multiple fractures of the ribs and of the skull. It is concluded that the losses due to crushing to death can be related to the decrease in vitality of the piglets due to diseases, caused in winter by decreased vitality and in summer by pressure caused by coli infection.

Animals↗
PubMed1987

The effects of postoperative factors on serum thyroid hormones and rat liver nuclear 3,5,3'-triiodothyronine receptor concentrations in surgical models of uremia and regenerating liver.

We have determined the individual effects of postoperative fasting, surgical/anesthetic factors, acute uremia (AU), and regenerating liver (RL) on nucleoplasmic (NP; 0.15 M KCl-extractable) and chromatin-bound (CB; 0.4 M KCl-extractable) rat liver T3 receptors. AU and RL rats were studied 24 h after bilateral nephrectomy (blood urea nitrogen, 128 +/- 13 mg/dl) or two thirds hepatectomy, respectively. The effects of postoperative fasting were assessed by comparison of normal rats (N) with control rats (N6) pair-fed to match the caloric intake of the AU and RL rats. Surgical/anesthetic effects were determined by comparison of N6 rats with sham-operated pair-fed rats (S6). The effects of AU or RL were obtained by comparison with S6 controls. Changes in mean body weight attributable to fasting (N6-N), surgical/anesthetic effects (S6-N6), acute uremia (AU-S6), and regenerating liver (RL-S6) were: -17.3 (P less than 0.001), -4.0 (P = NS), -4.5 (P less than 0.05), and -1.0 g/24 h (P = NS), respectively. Changes in mean serum T4 (N, 5.3 +/- 1.3 micrograms/dl) were: -1.0 (P = NS), -0.6 (P = NS), -0.9 (P less than 0.05), and -1.0 micrograms/dl (P less than 0.05), respectively. Changes in mean serum T3 (N, 53 +/- 23 ng/dl) were: -8 (P = NS), -18 (P less than 0.05), -10 (P = NS), and -14 ng/dl (P less than 0.05), respectively. The NP and CB receptor pools of the AU and RL rats were not significantly different from those of age-matched N rats (NP, 25 +/- 5 fmol/mg DNA; CB, 405 +/- 134 fmol/mg DNA). Chronically uremic (CU) rats 2 weeks after five sixths nephrectomy (blood urea nitrogen, 36 +/- 2 mg/dl) did not exhibit significant change in their extractable receptor pools. Complete starvation for 24 h (NO) or 72 h (NOO) generally resulted in marked reductions in receptor concentrations compared to those in age-matched N rats fed ad libitum: NP pool (N, 31 +/- 17 fmol/mg DNA): NO-N, -40% (P = NS); NOO-N, -59% (P less than 0.01); CB pool (N, 303 +/- 105 fmol/mg DNA): NO-N, -19% (P less than 0.05); NOO-N, -41% (P less than 0.001). These studies indicate that severe AU, moderate CU, and LR have relatively little effect on solubilized rat liver nuclear receptor concentrations. In contrast, complete starvation is a potent depressant of both nuclear receptor pools. In the surgical models of AU and LR, postoperative fasting was the primary cause of weight loss.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1985

Telangiectatic hamartoma of the iris and ciliary body.

Two cases of telangiectatic hamartoma of the iris and ciliary body are reported, one of them with its histopathological study. No previous cases have been found, as such, in the current literature. The most important descriptions of primary vascular lesions of the iris and ciliary body are briefly reviewed.

Adult↗
PubMed1984

[Familial mucosal neuromatosis: a minor form of the MEN-2b syndrome].

When the alert ophthalmologist found visible corneal nerves on a clear stroma, he must remind about the multiple endocrine neoplasia syndrome (M.E.N.-2b) and look for the medullary carcinoma of thyroid and the pheochromocytomas. Recognition of these ocular lesions as components of the syndrome is of the utmost importance because prompt identification of individuals affected by multiple endocrine neoplasia type 2 b facilitates early treatment of associated medullary thyroid carcinomas and pheochromocytomas. These endocrine neoplasias must be carefully searched by endocrine means. We present for the first time, in our knowledge, one family with M.E.N.-2b syndrome without endocrine neoplasias at this moment. We think it can be one minor presentation. We call this form "familial multiple mucosal neuromas".

Adolescent↗