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Biomedical subjects

N Sanchez

Publications and source records attributed to N Sanchez.

At least 19 recordsLinked to original sources
PubMed1997

Gaucher disease: enzyme therapy in the acute neuronopathic variant.

The responses to regular intravenous enzyme infusions were compared in two sibs with Gaucher disease type 2, the acute neuronopathic variant. Enzyme administration was begun at 7 months in patient 1 who had severe progressive visceral and neuronopathic disease. No significant effect of enzyme infusions was noted. Death occurred at 9 months. Patient 2 was prenatally diagnosed and enzyme infusions were initiated at age 4 days. Overall development progressed at a rate similar to her unaffected full sib until her death at 15.1 months. Slowly progressive esotropia, ocular paresis and dysphagia began at 8 months as did infiltrative pulmonary disease. Comparison of these clinical courses show significant visceral and neurologic effects of anticipatory enzyme therapy, but with unaltered outcome, for Gaucher disease type 2.

Gaucher Disease↗
PubMed1997

Evaluation of two competing methods for calculating Charlson's comorbidity index when analyzing short-term mortality using administrative data.

The performance and predictive power of the Deyo-Charlson and the Romano-Charlson comorbidity indices were compared when short-term mortality after hospitalization was the outcome of interest. These indices are commonly used to adjust for the effect of comorbidities when using administrative data in comparative studies. In hospital Medicare clam data for patients admitted to one of six medical categories (back pain, stroke, pneumonia, hip replacement, transurethral radical prostatectomy, or lysis of peritoneal adhesion), were selected for analyses. Logistic regression models were employed to evaluate the relative importance and the explanatory power of these indices for predicting mortality 30, 90, and 180 days after admission. The contribution of each index to mortality was assessed via the likelihood ratio chi-square statistic (G2), and the area under the receiver operator characteristic (ROC) curve was used to assess predictive power. Indices were evaluated using weights suggested by Charlson et al. and using empirically derived weights. Both indices improved the base model equally, although the predictive power of both indices was poor with values of the C statistic ranging from 0.60 to 0.78. Our results suggest limited applicability of these approaches when examining short-term mortality. A slight increase in predictive power was observed when indices were calculated using empirical weights derived from our data.

Chi-Square Distribution↗
PubMed1997

The effects of perceived stigma and psychological over-control on the behavioural problems of children with epilepsy.

This pilot study finds that parents who think that their child will be stigmatized and who perceive that epilepsy limits their child, report higher levels of four child behavioural problems than reported by other parents of children with epilepsy. Those children with epilepsy who report that their parents use an over-controlling psychological approach to parenting report higher levels of four behavioural problems than those children with epilepsy who do not report over-controlling behaviour from their parents. The effects of simple partial seizures and of seizure severity on children's behavioural problems are completely mediated by perceived stigma, perceived limitations, and perceived parenting. Seizure frequency, absence seizures, and treatment with ethosuximide have direct effects on three children's behavioural problems; the effects of these medical variables are generally unaffected by control for parent's and children's perceptions.

Adolescent↗
PubMed1997

The effect of accommodative hysteresis on apparent stationarity.

The potential contribution of accommodation to the ability to perceive whether an object is moving in space during lateral movement of the head was examined in 16 visually-normal young adults. The target, which provided a highly effective accommodation stimulus, was viewed monocularly in an otherwise completely darkened room. Self-generated head movements of controlled amplitude and frequency were used to produce lateral target motion of continuously variable amplitude either in-phase or counter-phase to the lateral translation of the head. Tonic accommodation and the target/head displacement ratio needed for apparent target stationarity were measured before and after sustained focus at either the nearpoint or farpoint. Tonic accommodation shifted inward under the nearpoint condition and outward under the farpoint condition. The tonic aftereffects induced under the nearpoint and farpoint conditions were accompanied by increases and decreases, respectively, in the degree of positive (same direction as the head) concomitant motion required for apparent target stationarity. These results suggest that the altered accommodative effort required to compensate for the tonic aftereffects influenced the magnitude of the absolute visual parallax ascribed to self-motion. The accommodative system therefore appears to contribute to position constancy, at least in a relatively impoverished visual environment.

Accommodation, Ocular↗
PubMed1996

The relationship of episiotomy to third and fourth degree lacerations.

Third and fourth degree lacerations can produce significant long term morbidity to women undergoing childbirth. The incidence of third and fourth degree lacerations is variable depending on the institution and the obstetrical provider. While episiotomy remains a valuable intervention in selected cases, an improvement program directed at lowering the use of episiotomy can reduce the incidence of this clinical event. Hospitals and physicians with higher rates of third and fourth degree tears should examine the use of episiotomy, and midline episiotomy in particular, which is associated with an increased incidence of third and fourth degree tears.

Adolescent↗
PubMed1996

The cooperative cardiovascular project an AFMC special report.

Patients who suffer myocardial infarction can have improved outcomes if the following elements are part of their treatment plans: 1. Rapid diagnosis of the condition. 2. Use of thrombolytics or angioplasty early in the presentation, if appropriate. 3. Use of aspirin early in the course of care. 4. Discharge medications of aspirin and beta blockade, in appropriately selected patients. 5. Documentation of efforts to counsel the patient to quit smoking. The above material outlines the key indicators in the national project to improve care for heart attack victims. Hospitals should assess the diagnosis, immediate care, and long-term management of patients with this condition. Patients have a variety of comorbidities and do not always fit into a simplified therapeutic scheme. Nevertheless, the care of myocardial infarction victims in the pilot CCP states demonstrated that a sizable number of these patients could benefit from a more focused approach to the above therapeutic interventions.

Adrenergic beta-Antagonists↗
PubMed1994

Gallbladder surgery for Medicare patients in Mississippi.

Mississippi Foundation for Medical Care (MFMC) conducted a review of gallbladder surgery performed on Mississippi Medicare Patients using hospital claims files and limited record review for verification of claims file data. Significant error rates in the surgeon identification number were found in the claims files. It should also be noted that the current ICD-9-CM coding system does not allow for identification of laparoscopic cholecystectomies converted to open procedures. Past studies have attempted to use claims data alone for these types of analyses. These findings demonstrate the importance of using caution by those attempting to use claims data (without verification) to define patterns of hospital utilization, clinical outcomes and/or physician profiling. Claims data must be tested for validity for reliable pattern analysis. In addition, considerable variation was found among providers in elements such as conversion rates, complication and readmission rates. A few surgeons showed patterns for critical variables that were quite different from the universe. There was however, no statistically significant differences associated between volume of cases performed and outcomes. Time frame comparisons over several years show significant (> 80%) increase in gallbladder surgery since the introduction of the laparoscopic procedure.

Cholecystectomy↗
PubMed1993

Chromatic aberration and ocular focus: Fincham revisited.

Longitudinal chromatic aberration of the eye (LCA) produces "color fringes" at edges that specify focus. Fincham [(1951) British Journal of Ophthalmology, 35, 381-393] concluded that these chromatic effects were important for accommodation, but most investigators disagree. We monitored accommodation in 25 subjects while they viewed a sinusoidally moving target (1.5-2.5 D at 0.2 Hz) in a Badal optometer. The target was monochromatic (590 nm with 10 nm bandwidth), or white (3000 K) with LCA normal, neutralized or reversed. Sensitivity to the effects of LCA is profound and widespread. Gain decreases substantially and phase-lag increases when LCA is eliminated, and reversing the aberration severely disrupts accommodation. The ordered arrangement of spectral foci produced by LCA seems to be a fundamental aspect of the stimulus for "reflex" accommodation.

Accommodation, Ocular↗
PubMed1992

von Willebrand factor antigen, tissue-type plasminogen activator antigen, and risk of death in human immunodeficiency virus 1-related clinical disease: independent prognostic relevance of tissue-type plasminogen activator.

Tissue-type plasminogen activator, von Willebrand factor, and plasminogen-activator inhibitor type 1 plasma levels were measured at first consultation in 85 consecutive patients infected with human immunodeficiency virus. Patients were assigned to three groups according to clinical status: mild disease group, intermediate group, and acquired immunodeficiency syndrome group. Significant differences were found in von Willebrand factor, tissue-type plasminogen activator, and plasminogen-activator inhibitor type 1 plasma levels among the three groups: severe clinical status was associated with higher von Willebrand factor, tissue-type plasminogen activator, and plasminogen-activator inhibitor type 1 plasma levels. Significant correlations were found among these three parameters, such known biologic prognostic indicators of human immunodeficiency virus infection as IgA, anti-p24 antibodies, p24 antigenemia, CD4+ lymphocytes, beta 2-microglobulin, and the clinical status. The prognostic relevance of plasma von Willebrand factor and tissue-type plasminogen activator levels at the time of entry into the study was then investigated in a cohort of 65 of the 85 patients who had follow-up during a median period of 22 months. The median survival time for all patients was 39 months after the first consultation. A plasma von Willebrand factor level greater than 200% of the control value had a positive predictive value of 86% for determining nonsurvivors; the median survival time for such patients was 9 months after the first consultation. A positive predictive value of 100% in recognizing nonsurvivors was found for tissue-type plasminogen factor plasma levels greater than 20 ng/ml; the median survival time for these patients was 2 months after the first consultation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Endothelial mediators regulating vascular tonus].

Vascular endothelium is the unavoidable interface between blood and tissues. Its role as regulator of vascular tone is discussed here. The endothelium possesses different receptors for vasoactive mediators. These receptors activate the endothelial cells which in turn may produce secondary mediators acting on smooth muscle cells by activating or inhibiting their contraction. Such mediators are the endothelins which have a vasoconstrictor effect, and prostacyclin or endothelium-derived relaxation factors (EDRF) which have a vasodilator effect. Thus, the vascular endothelium and the mediators it secretes play a crucial role in vascular tone physiology.

Endothelins↗
PubMed1990

Impact of smoking, physical training and weight reduction on FVII, PAI-1 and hemostatic markers in sedentary men.

The variations of FVII, PAI-1, TAT complexes, fibrinopeptide A, D-Dimers and beta thromboglobulin plasma levels were studied on 30 sedentary men, smokers and non-smokers, who were admitted to a 6 months' program of physical training and smoking cessation. After 3 months of intervention, sustained physical training was associated with the decrease of FVII and PAI-1 levels. Mild exercise performed during a second 3-month period could maintain normal FVII and PAI-1 activities but participants who stopped the training increased their FVII and PAI-1 plasma levels. FVII was not influenced by smoking habits. Smoking cessation seemed to slightly potentiate the decrease of PAI-1 levels associated with mild exercise. Overweight, FVII and PAI-1 levels were correlated and the weight reduction induced by training was related to the changes in the factors. In smokers, physical exercise was associated with a significant increase of hemostatic markers. This exercise-induced variation disappeared after 3 months of intervention in participants who stopped smoking and reappeared in those who smoked again after 6 months of intervention. This finding was not influenced by the physical training program.

Antithrombin III↗
PubMed1990

Impaired fibrinolytic capacity in patients with inflammatory bowel disease.

The venous occlusion test was applied to 17 patients with inflammatory bowel disease (IBD; 7 cases of Crohn's disease, 10 cases of ulcerative colitis). Results were compared to those obtained in 20 healthy matched control subjects. Patients with IBD had significantly decreased t-PA Ag release (p less than 0.001) and had no significant vWF Ag release. Residual PAI activity was evidenced after venous stasis in the IBD group but not in the control group. Hypofibrinolysis was more important in patients with an evolutive IBD than in patients with IBD in remission. Impaired systemic fibrinolytic capacity might contribute to an increased risk for thromboembolic complications and to the pathogenesis of inflammatory bowel disease.

Adult↗
PubMed1989

Isolation and characterization of a fibrinogen-clotting enzyme from venom of the snake, Lachesis muta muta (Peruvian bushmaster).

A fibrinogen-clotting enzyme from the venom of the Peruvian bushmaster snake was purified to homogeneity by gel filtration on Sephadex G-100 followed by DEAE-cellulose ion-exchange chromatography using a linear ionic strength gradient with NaCl. The specific activity of the enzyme was 866 NIH U/mg, representing a 55-fold purification, with a recovery of 45%. The amino acid composition was Asx30, Thr14, Ser15, Glx33, Pro23, Gly22, Ala15, Val22, Cys18, Met3, Ile18, Leu23, Tyr2, Phe13, His8, Lys11, Arg11. The total carbohydrate content was 13.4%, comprised of 3.4% hexose, 8.7% hexosamine and 1.3% sialic acid. The enzyme was active against the synthetic amide substrate alpha-N-benzoyl-DL-arginine-p-nitroanilide (BAPNA) and against the ester substrates alpha-N-benzoyl-L-arginine ethyl ester (BAEE) and tosyl-L-arginine methyl ester (TAME). Kinetic parameters for TAME esterolysis were: Vmax, 135 mumoles/min/mg and Km, 2.5 x 10(-4) M. The pH optimum was 8.0. Vmax for BAPNA amidolysis was 0.363 mumoles/min/mg and Km, 7.5 x 10(-5) M. Enzyme activity was reduced by diethylpyrocarbonate and by photo-oxidation, suggesting that the enzyme is a serine protease with a histidine residue involved in the active site. The enzyme released fibrinopeptide A rapidly from purified human fibrinogen and fibrinopeptide B more slowly. Factor XIII was not activated and the clotting activity was not inhibited by heparin. A dose of 50 micrograms/kg brought about defibrinogenation in anaesthetized rats but rabbits were unaffected. A dose of 80 micrograms/kg defibrinogenated conscious rats after 5 hr. There were no hypotensive or haemorrhagic effects.

Amino Acids↗