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Biomedical subjects

P Pastor

Publications and source records attributed to P Pastor.

At least 19 recordsLinked to original sources
PubMed1997

Pleural and peritoneal leishmaniasis in an AIDS patient.

The case of an AIDS patient who developed pleuritis and peritonitis in the course of relapsing visceral leishmaniasis is reported. Visceral leishmaniasis, considered an opportunistic infection in patients infected with the human immunodeficiency virus (HIV) who live in endemic areas, has a chronic relapsing course. Typical manifestations such as fever, hepatosplenomegaly, lymphadenopathy, weight loss, or pancytopenia are not specific in advanced HIV infection. Atypical clinical presentations are becoming more frequent. This is believed to be the first report of peritoneal involvement by Leishmania in an AIDS patient.

AIDS-Related Opportunistic Infections↗
PubMed1997

Factors associated with unnecessary immunization given to children.

OBJECTIVE: To determine the factors associated with unnecessary immunization during the pre-school years. METHODS: Children were selected from birth certificates and their parents were interviewed to identify all immunizations to 72 months of age. The immunizations were verified. RESULTS: Of 187 children studied 34 (18%) received unnecessary immunization. Unnecessary immunization was strongly associated with ever receiving immunization in a large system of public clinics (designated "Public A") (33%) compared with other providers (5%) (P < 0.00001). Among children immunized in Public A, unnecessary immunization was associated with the parent having an incomplete or no copy of the child's immunization record (P = 0.007) and with not being up to date for immunizations at 24 months of age (P = 0.04). Complete documentation of immunizations either in the Public. A record or in the parent's copy of the record was associated with a 4% rate of unnecessary immunization; incomplete or no documentation in both the Public A and the parent's record was associated with a 45% rate of unnecessary immunization (P = 0.001). CONCLUSIONS: Access to a complete immunization record, be it the provider's, the parent's or ideally both, decreases substantially a child's risk of unnecessary immunization.

Analysis of Variance↗
PubMed1995

Pediatric clinical clerkships are associated with an excess risk of acute infection.

OBJECTIVE: To determine the incidence of acute respiratory and gastrointestinal tract illness and associated absence by third-year medical students during pediatric and nonpediatric (control) clinical clerkships. DESIGN: A self-administered questionnaire was completed by students after the first 4 weeks of two pediatric clerkships (inpatient and outpatient) and two non-pediatric clerkships (obstetrics-gynecology and psychiatry). Information was obtained on the symptoms of acute respiratory and gastrointestinal tract illness and related absences. ANALYSIS: Results from each student's pediatric clerkship were compared with the results from the same student's control clerkship by means of matched-pair analysis. SUBJECTS: Students who made up the junior class at the University of Texas Southwestern Medical School at Dallas, July 1, 1990, to June 30, 1991. RESULTS: Of 177 students (77%) who completed questionnaires after one pediatric and one control clerkship, 108 students (61%) had had an acute illness while on pediatric clerkships in contrast to 69 students (39%) on control clerkships (odds ratio, 3.3; 95% confidence interval, 2.0 to 5.4; P < .001). More students were absent for illness during pediatric than control clerkships (23 [13%] vs nine [5%], respectively; odds ratio, 2.7; 95% confidence interval, 1.2 to 6.2; P = .02). The higher risk of illness during pediatric clerkships was not related to the order of the pediatric or control clerkship, the order of inpatient and outpatient pediatrics, or the season of the year. CONCLUSION: Pediatric clinical clerkships in the third year of medical school were associated with excess morbidity from acute infectious illness. Studies are needed to determine whether emphasizing infection control practices decrease this morbidity and any resulting nosocomial spread to patients.

Absenteeism↗
PubMed1995

Estimating immunization coverage from school-based childhood immunization records.

To determine the accuracy of school-based childhood immunization records and to describe the effects of their use on estimates of community-wide immunization coverage, we verified the immunizations to 72 months of age for children born in 1986 to residents in Dallas County, TX, and in Minnesota. Verified immunizations were compared with those documented in the school record. Major transcription errors accounted for fewer than 1% of discrepancies between school and provider records. For 99 subjects with 987 verified immunizations in Minnesota, age-appropriate immunization coverage estimated from the school records was within two percent of actual coverage. For 86 subjects with 981 verified immunizations in Dallas County, age-appropriate immunization coverage from the school records underestimated actual coverage by as much as 21%. The primary factor explaining the underestimate in Dallas was incomplete school immunization records for 33 (38%) subjects and 126 (13%) immunizations. Selective recording of immunizations related to the minimum state requirements in Texas contributed to incomplete school records in Dallas County. Verification of the completeness of records selected to estimate immunization coverage is essential if the estimates are used to monitor trends or to make public policy decisions.

Child↗
PubMed1995

[Cerebral vascular complications in Conn's disease: report of two cases].

We report two patients with arterial hypertension (AHT) secondary to Conn's disease and cerebral vascular accident (CVA). Both had histories of long-standing AHT that had been poorly controlled with drugs, though no complications had developed up to the time of presentation. One CVA was a hemorrhage in the right capsular-lenticular region and the other was a cerebral ischemic infarction. Blood tests done upon admission found low potassium levels. The final clinical-pathological diagnosis was primary hyperaldosteronism secondary to suprarenal adenoma. After laparoscopic surgery AHT reverted to normal in one patient. Although Conn's disease is a rare cause of AHT, early diagnosis and treatment can provide a cure and prevent the development of severe complications.

Adenoma↗
PubMed1994

[Evaluation of prostatic specific antigen after a digital rectal examination: experience with 36 patients].

Levels of prostatic specific antigen may be modified with procedures over the prostatic gland. We measured this antigen in 36 hospitalized patients before and immediately after a digital rectal examination. Antigen levels were 8.3 +/- 21.3 ng/ml before and 13.8 +/- 27.5 ng/ml after the examination (NS). It is concluded that digital rectal examination did not modify antigen levels in our sample.

Adult↗
PubMed1993

Declining incidence of Haemophilus influenzae type b disease since introduction of vaccination.

OBJECTIVE: To determine the incidence of invasive Haemophilus influenzae type b disease in children living in Minnesota and Dallas County, Texas, before and since introduction of plain polysaccharide vaccine in 1985, and conjugate vaccine in 1988. Initially, use of these vaccines was limited to infants 18 months of age and older. DESIGN: Identification of culture-proven cases of H influenzae type b disease was through systems of active, laboratory-based surveillance. The mean incidence of disease (cases observed/100,000 child-years) for 1983 and 1984 served as a baseline for comparison with subsequent years through 1991. PARTICIPANTS: Children less than 5 years of age in Minnesota and Dallas County, Texas. Overall, there were 2557 confirmed age-eligible cases of invasive H influenzae type b disease from 1983 through 1991. RESULTS: Between the 1983-1984 baseline and 1991, the incidence of H influenzae type b disease decreased 85% in Minnesota and 92% in Dallas. Notably, declines in incidence were observed in children in the age group being vaccinated as well as in infants younger than 18 months of age prior to introduction of vaccination. CONCLUSION: In two widely separated areas of the United States, a profound decrease in the incidence of H influenzae type b disease has occurred. The data suggest that vaccination may be protecting against disease, as well as decreasing the spread of infection to unvaccinated infants.

Bacterial Capsules↗
PubMed1993

Ethnicity and socioeconomic status: impact on the diagnosis of congenital heart disease.

OBJECTIVES: The purpose of this study was to estimate the prevalence rates of specific cardiac defects for three ethnic groups and to determine the effects of ethnicity, family income and household education level on the timing of referral for pediatric cardiac care. BACKGROUND: Previous studies examining ethnic differences in rates of congenital heart disease were based on hospital referrals or were limited to diagnoses made in the 1st year of life. These limitations may lead to potential biases in the ascertainment of cases. The present study is population based and includes patients diagnosed after the 1st year of life. METHODS: Cases of congenital heart disease were enumerated among 379,561 liveborn infants to black, white and Mexican-American residents in Dallas County, Texas. Diagnosis was made on the basis of examination by a pediatric cardiologist, two-dimensional echocardiographic studies, cardiac catheterization or observations at operation or at autopsy. Ethnicity, median family income and household educational level were determined from birth certificate information. RESULTS: White children had higher prevalence rates for aortic stenosis, endocardial cushion defect and ventricular septal defect. Mexican-American children had the lowest rate for hypoplastic left heart syndrome. The median age at referral to a pediatric cardiologist was 1.9 months for blacks, 2.1 months for whites and 2.2 months for Mexican-Americans. Stratifying the cases by median family income and household educational level failed to show any significant relation to age at referral. CONCLUSIONS: Prevalence rates of specific cardiac defects vary among black, white and Mexican-American children, probably reflecting different genetic and environmental backgrounds. The timing of referral for pediatric cardiac care, however, was not related to ethnicity, median family income or household educational level.

Black or African American↗
PubMed1993

Decreased Haemophilus colonization in children vaccinated with Haemophilus influenzae type b conjugate vaccine.

OBJECTIVE: The incidence of invasive Haemophilus disease has unexpectedly decreased in unvaccinated children since the introduction of conjugate vaccine in the United States. The purpose of this study was to determine whether conjugate vaccination decreases colonization with Haemophilus influenzae type b. DESIGN: This study was a prospective, bimonthly survey of pharyngeal colonization with H. influenzae type b in children attending day care from October 1987 through September 1989. Vaccination status was determined from the medical record. SUBJECTS: We obtained 1188 pharyngeal cultures from 283 healthy children, 18 to 59 months of age; 51 children had received unconjugated polysaccharide vaccine (PRP), and 89 had received conjugate vaccine (94% PRP-diphtheria toxoid). MEASUREMENTS AND RESULTS: Multivariate analysis was used to test the possibility of an association between vaccination status and the rate of colonization with H. influenzae type b. Among children known to be exposed to at least one child with a positive culture result, the efficacy of conjugate vaccination to prevent H. influenzae type b colonization in an unmatched analysis was 64% (95% confidence interval: 5%, 86%; p = 0.02) and in a matched analysis 81% (95% confidence interval: 7%, 96%; p = 0.02). No effect on colonization was found with PRP vaccination. CONCLUSIONS: Conjugate vaccination decreases H. influenzae type b pharyngeal colonization and thereby may decrease transmission of this agent among healthy children.

Bacterial Proteins↗
PubMed1992

Segmental systolic responses to brief ischemia and reperfusion in the hypertrophied canine left ventricle.

OBJECTIVES AND BACKGROUND: Left ventricular hypertrophy is associated with increased mortality, increased myocardial infarct size and an increased incidence of sudden death. Although reperfusion after ischemia has been shown to result in decreased infarct size and recovery of systolic thickening, it is unknown how left ventricular hypertrophy might influence recovery of regional systolic thickening after ischemia and reperfusion. We hypothesized that left ventricular hypertrophy might attenuate or abolish the functional response to reperfusion. METHODS: Three groups of chronically instrumented, conscious dogs (dogs with left ventricular hypertrophy and hypertension; dogs with left ventricular hypertrophy and reduced blood pressure and a control group without hypertrophy and with normal blood pressure) underwent 15 min of ischemia and 24 h of reperfusion. Segmental systolic thickening was measured by sonomicrometers and myocardial segments were grouped by percent of control segmental systolic thickening retained at 15 min of ischemia (class 1 greater than or equal to 67%, class 2 from 0% to 66%, class 3 less than 0% control systolic thickening). The recovery of each class of segment was measured serially during reperfusion. Hemodynamic variables and regional myocardial blood flow were also measured. RESULTS: There were no differences among groups in recovery of segmental systolic thickening for class 1 segments. Systolic thickening in class 2 (hypokinetic) segments was significantly depressed (p less than 0.05 compared with control value) in the group with left ventricular hypertrophy and reduced blood pressure (but not in the group with hypertrophy and hypertension) during early reperfusion; systolic thickening in class 3 (dyskinetic) segments showed a similar trend in the group with hypertrophy and reduced pressure. CONCLUSIONS: Although left ventricular hypertrophy with hypertension did not attenuate the contractile response to reperfusion, hypertrophy with reduced blood pressure was associated with significantly greater depression of segmental systolic thickening early during reperfusion.

Animals↗
PubMed1992

Invasive Haemophilus influenzae type b disease in children less than 5 years of age in Minnesota and in Dallas County, Texas, 1983-1984.

During 1983 and 1984, 733 cases of invasive Haemophilus influenzae type b disease in children less than 5 years of age were identified in Minnesota and in Dallas County, Texas. The overall incidence of disease was lower in Minnesota than in Dallas County. However, among urban residents, the rates of disease for whites were similar in the two areas. A higher rate of disease among whites in urban Minnesota compared with rural Minnesota resulted from an increased rate of cases for diagnoses other than meningitis. Local practices might have affected the rate of certain diagnoses, since ascertainment of Hib disease other than meningitis is more dependent on diagnostic practices than is diagnosis of meningitis. These data suggest that the incidence of invasive H. influenzae type b disease is influenced by the racial composition of the population, the rates of disease in specific subgroups, and possibly by local medical practices. Understanding the factors that contribute to the incidence of disease is necessary to interpret variations in different populations and changes over time.

Age Factors↗
PubMed1991

Development of a three-dimensional finite element model of a human tibia using experimental modal analysis.

The modal analysis of a human tibia consisted of characterizing its dynamic behavior by determining natural frequency, damping ratio and mode shapes. Two methods were used to perform the modal analysis: (1) a finite element method (structural model); (2) an experimental modal analysis (modal model). The experimental modal model was used to optimize the structural model. After optimization, differences in results between the two models were found to be due only to mechanical properties and mass distribution. The influences of boundary conditions and geometric properties (such as inertia and length) were eliminated by the finite element model itself. The percent relative error between the two methods was approximately 3%, corresponding to the standard deviation of the measured frequencies. For the frequency range considered, the mode shapes were bending modes in two different vibration planes (latero-medial and sagittal), with a slight torsion effect due to the twisted geometry of the tibia.

Biomechanical Phenomena↗
PubMed1990

Differential enhancement of postischemic segmental systolic thickening by diltiazem.

Prolonged depression of segmental systolic thickening after brief coronary artery occlusion may result principally from events during reperfusion rather than during the ischemic interval. Thus, cellular calcium overload at reperfusion may be a mediator of contractile dysfunction after brief ischemia, and reduction of calcium entry by diltiazem, a calcium channel antagonist, may enhance recovery of systolic thickening after brief periods of ischemia. Thirteen awake unsedated dogs instrumented with hemodynamic catheters, left anterior descending coronary artery occluders and five to six pairs of intramyocardial sonomicrometers underwent two 15 min coronary artery occlusions with 24 h reperfusion. The order of infusion of diltiazem (15 micrograms/kg per min) or saline solution was alternated. Systolic thickening, hemodynamic variables and regional myocardial blood flow were measured serially over 24 h. Despite equally severe ischemic dysfunction during coronary occlusion, diltiazem-treated segments with systolic thinning during ischemia recovered control segmental thickening significantly earlier than saline solution-treated segments (at 30 versus 180 min of reperfusion). Blood pressure was mildly decreased during diltiazem treatment; therefore, a second group of 10 dogs underwent a similar occlusion and reflow period during infusion of nitroprusside to lower mean arterial pressure equivalently. Decreases in blood pressure in this group resulted in some improvement in segmental systolic function; however, this did not reach statistical significance at any time. Regional myocardial blood flows were similar in the saline solution- and diltiazem-treated groups during ischemia and reflow. Thus, it is concluded that 1) diltiazem infusion significantly enhanced recovery of segmental systolic thickening after 15 min of ischemia and 24 h of reperfusion; 2) the enhancement in segmental systolic function could not entirely be attributed to decreased mean arterial pressure; 3) improvement in postischemic segmental ventricular function was seen only in those segments with systolic thinning during ischemia; thus, segments with the most severe ischemic dysfunction benefited most; and 4) there were no important differences in regional myocardial blood flow during ischemia and reperfusion between saline- and diltiazem-treated animals.

Animals↗
PubMed1990

Trends in congenital heart disease in Dallas County births. 1971-1984.

To examine the changes in birth cohort prevalence rates and severity of congenital heart disease, we studied children with congenital heart disease born to blacks, whites, and Mexican-Americans in Dallas County from 1971 through 1984. Diagnoses were made by pediatric cardiologists' clinical evaluations, echocardiography, catheterization, surgery, or autopsy. During this study period, 2,509 of 379,561 liveborn infants were diagnosed, a prevalence rate of 6.6/1000. The rates for whites was significantly higher than for blacks or Mexican-Americans--7.2/1,000, 5.6/1,000, and 5.9/1,000, respectively. The rate for severe cases requiring cardiac catheterization or surgery or undergoing autopsy was 3.1/1,000 and did not differ among the three groups. The time trend for rates of congenital heart disease suggested an apparent increase in prevalence rate during the 1970s; however, the prevalence rate of severe forms remained relatively stable. This indicates that the apparent rise in prevalence could be accounted for by an increase in detection of mild cases. These findings were interpreted as reflecting a greater tendency for pediatricians to refer asymptomatic children with significant heart murmurs to a pediatric cardiologist.

Black People↗
PubMed1990

Potentiation of reperfusion-associated ventricular fibrillation by left ventricular hypertrophy.

Important electrophysiological alterations that may predispose hearts to arrhythmias have been described for hypertrophied myocytes, and hypertrophy coupled with ischemia has been associated with an increased incidence of sudden death; however, an influence of hypertrophy on reperfusion arrhythmias has not been previously described. We hypothesized that reperfusion-associated arrhythmias would be potentiated by left ventricular hypertrophy. After induction of renovascular hypertension, 37 awake, unsedated dogs (17 with left ventricular hypertrophy and 20 without hypertrophy) underwent 15 minutes of coronary artery occlusion and reperfusion. All dogs were pretreated with lidocaine bolus injections and with lidocaine by continuous infusion during coronary occlusion and reperfusion. Reperfusion-associated ventricular fibrillation occurred in seven of 17 dogs with left ventricular hypertrophy versus one of 18 dogs without hypertrophy (p less than or equal to 0.05). The presence of hypertension was not significantly associated with an increased incidence of reflow ventricular arrhythmias. Neither QT interval nor area-at-risk was different between the dogs with and without reperfusion ventricular fibrillation; however, increased heart rate just before reperfusion did correlate with an increased incidence of ventricular fibrillation at reperfusion. Thus, 1) left ventricular hypertrophy was associated with a significantly increased incidence of reperfusion-induced ventricular fibrillation after 15 minutes of ischemia, 2) this increased incidence was independent of the presence of hypertension, and 3) lidocaine protected control and hypertrophied hearts against ventricular fibrillation during ischemia but was ineffective in protecting hypertrophied hearts against reperfusion-induced ventricular fibrillation.

Animals↗