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Biomedical subjects

L Suarez

Publications and source records attributed to L Suarez.

At least 55 records · Page 3Linked to original sources
PubMed1987

Converting enzyme inhibition and kidney function in normotensive diabetic patients with persistent microalbuminuria.

The effects of a long term reduction in blood pressure on the kidney function of normotensive diabetic patients who had persistent microalbuminuria (30-300 mg albumin/24 hours) were studied in two groups of 10 such patients before and during six months of treatment with either 20 mg enalapril or placebo daily. Treatments were assigned randomly in a double blind fashion. Before treatment both groups had similar clinical characteristics, weight, diet, total glycosylated haemoglobin, median albumin excretion rate (enalapril group 124 mg/24 h, placebo group 81 mg/24 h), and mean arterial pressure (enalapril group 100 (SD 8) mm Hg, placebo group 99 (6) mm Hg). During treatment weight, urinary urea excretion, and total glycosylated haemoglobin remained unchanged. The mean arterial pressure decreased in the enalapril group but not in the placebo group (enalapril group 90 (10) mm Hg, placebo group 98 (8) mm Hg). The median albumin excretion rate also fell in the enalapril group but not in the placebo group (enalapril group 37 mg/24 h, placebo group 183 mg/24 h.) The glomerular filtration rate rose in the enalapril group from 130 (23) ml/min/1.73 m2 to 141 (24) ml/min/1.73 m2, and total renal resistances and fractional albumin clearance decreased while fractional albumin clearance increased in the placebo group. These results show that in patients who have diabetes but not hypertension a reduction in blood pressure by inhibition of converting enzyme for six months can reduce persistent microalbuminuria, perhaps by decreasing the intraglomerular pressure.

Adult↗
PubMed1987

A linear systems approach to analyzing the pharmacokinetics of carbon tetrachloride in the rat following repeated exposures of 8 and 11.5 h/day.

Ten- and 12-h workdays are relatively common in the chemical and other non-labor intensive industries both in the United States and Europe. Based on pharmacokinetic principles, persons who work 10-12 h shifts and are exposed to chemicals with a terminal half-life between 5 and 200 h will absorb a larger quantity of the toxicant or have higher peak blood levels than persons who work 8-h shifts. To evaluate the effects of exposure duration and repeated exposure on the elimination of carbon tetrachloride (CCl4), rats were repeatedly exposed to 100 ppm 14CCl4 for either 8 or 11.5h/day. Pharmacokinetic equations which describe the plasma concentration and pulmonary elimination during and following single and repeated inhalation exposures were developed. These equations are based on a diffusional type of input function and a linear systems analysis approach. They can be used to make predictions of the cumulation of toxicant following repeated exposure, the relative change in the plasma level following multiple exposures, and the steady-state plasma level based only on the elimination of the chemical in the breath. The pharmacokinetic analysis indicated that rats repeatedly exposed to 100 ppm CCl4 for 11.5 h/day for 4 days per week, or 8 h/day for 5 days per week, will not have increasing plasma levels. The analysis also predicted no significant difference in the peak plasma concentration of CCl4 between the 8 and 11.5h/day schedules following either 1 or 2 weeks of exposure. Due to rapid pulmonary elimination by the rat, the steady state plasma level of CCl4 was reached after only three consecutive exposures for both schedules. The alpha and beta half-lives (X +/- SE) of pulmonary elimination for the 8 h/day group were 84 +/- 9 min and 400 +/- 32 min, respectively. The half-lives for the 11.5 h group were 91 +/- 6 min and 496 +/- 32 min, indicating that the beta phase half-life was significantly longer than that of the 8-h group. This observation, coupled with the tissue distribution data (Paustenbach et al. 1986), suggests that during the longer exposure period a greater fraction of CCl4 is placed in the poorly perfused tissues like fat, thus altering the time-course of elimination in the breath. A general formula for adjusting TLVs for unusually long work schedules is also developed and presented.

Animals↗
PubMed1987

Bilio-pancreatic common channel in children. Clinical, biological and radiological findings in 12 children.

Twelve patients (11 girls and 1 boy) with dilated bile ducts and anomalous junction between the common bile duct and pancreatic duct are reported. All patients underwent preoperative opacification of the bile ducts either by transhepatic cholangiography or percutaneous cholecystography. Abdominal pain and jaundice were the main clinical symptoms. Reflux of pancreatic enzymes in the bile duct was proven by measuring amylase and lipase activity in the biliary system after IV injection of 1 IU/kg of cholecystokinin. All patients were operated upon. Bile ducts size returned to normal in all patients who are clinical well with a follow-up from 1 to 6 years.

Adolescent↗
PubMed1987

Fatal occupational injuries of women, Texas 1975-84.

A review of Texas death certificates for 1975-84 identified 348 cases of fatal occupational injuries of civilian females. Homicides accounted for 53 per cent and motor vehicle-related injuries accounted for 26 per cent of the deaths. Injuries from firearms caused 70 per cent of the homicides. One hundred thirty-three deaths occurred to women employed in the retail trade industry; of these, 77 per cent resulted from homicide. Women workers in gasoline service stations, food-bakery-and-dairy stores, and eating-and-drinking places had especially high risks of homicide. Texas female heavy-truck drivers had the highest fatal-injury rate, with motor-vehicle-related injuries causing 89 per cent of their deaths. These results indicate that effective strategies to prevent fatal occupational injuries of Texas women will need to address the problems of workplace violence and the hazards posed by motor vehicles.

Accidental Falls↗
PubMed1987

Primary liver cancer mortality and incidence in Texas Mexican Americans, 1969-80.

During the years 1969-80, primary liver cancer mortality rates for Mexican American males were 2.2 times higher than for other Whites; Mexican American females had rates 2.8 times higher than other White females. Age-specific mortality rates showed even higher risks for older Mexican Americans exceeding both other White and Black rates three to four-fold. Incidence data for El Paso County (Texas) confirmed the increased risk for Mexican American males (risk ratio = 2.3) and females (risk ratio = 13.7). Cirrhosis mortality was also higher in Texas Mexican Americans but risk ratios were not as large as seen for primary liver cancer.

Adult↗
PubMed1987

Cancer mortality among Mexican Americans and other whites in Texas, 1969-80.

Cancer mortality in Texas 1969-80 was 25 per cent lower among Mexican American males compared to other Whites; among females, rates were only 4 per cent lower. Reduced mortality was primarily a result of lower rates for cancers of the most common sites: lung, colon, breast and prostate. However, for cancers of the stomach, liver, and gallbladder, Mexican Americans had higher rates than other Whites. Female Mexican Americans were also at a higher mortality risk for cervical cancer. Implications are discussed.

Female↗
PubMed1987

Laser immunonephelometry for routine quantification of urinary albumin excretion.

We describe a laser-immunonephelometric method for quantifying urinary albumin excretion (UAE) in large numbers of samples. For a 150-microL sample incubated at room temperature for 45 min with 40 microL of antiserum specific for human serum albumin, the assay range for albumin was 0.34 to 43.0 mg/L. For samples analyzed undiluted and diluted 10-fold, the range of measurable albumin was from 0.34 to 430.0 mg/L. With an automated version of this method, one can assay 240 samples per hour. Intra- and interassay CVs were less than 6% and 9%, respectively. Measurements by this method (y) correlated well with those obtained by a RIA method (x): y = 1.00x + 0.163 mg/L (n = 233; r = 0.996). The day-to-day CV for UAE was determined for three consecutive determinations done on each of 60 controls according to the time of collection and in 212 diabetics according to the amount of 24-h UAE. For controls, UAE was 8.0 +/- 8.1 mg/24 h (mean +/- SD), CV 44 +/- 23%. The CV was similar for diurnal (50 +/- 28%) and overnight (58 +/- 32%) collections from controls; and for diabetics with normal values for UAE: 35 +/- 32%, with slight albuminuria (25-300 mg/24 h):37 +/- 28%, or with macroalbuminuria (greater than 300 mg/24 h): 47 +/- 42%.

Adult↗
PubMed1986

Exercise testing and thallium-201 myocardial perfusion scintigraphy in the clinical evaluation of patients with Wolff Parkinson White syndrome.

In 58 patients with Wolff Parkinson White syndrome (WPW), we performed exercise stress testing in order to investigate the incidence of normalization of the auriculo-ventricular conduction and the ST-segment changes. For a more accurate evaluation of the latter, exercise and redistribution radionuclide images with Thallium-201 were obtained in 18 cases. Forty-nine had type A and nine had type B of WPW. Forty-eight had permanent, four had alternant and six had no pre-excitation (PE) when they started the test. Mean maximal functional capacity, mean maximal heart rate and mean maximal double product were not different when compared to an age-matched control group. Of the 48 patients who began the test with PE, in 23 (48%) it disappeared while PE persisted in 25 (52%). In 16 cases the disappearance of the PE was sudden and in seven it was progressive. Pre-excitation persisted in 39.5% of patients with type A and in 88.8% with type B (p less than 0.01). ST-segment depression was observed in 76.6% of patients with PE and in 28.6% of cases without PE (p less than 0.01). ST-segment depression occurred in 44.8% of patients with type A and in 100% of cases with type B (p less than 0.05). Transient abnormal Thallium-201 scans were observed in 62.5% of patients without PE and in 20% with PE. No patients showed exertional arrhythmias. This study suggests the possibility of measuring the duration of the refractory period of the accessory pathway in those patients in which the PE disappears suddenly, at a given heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

Contaminated produce--a common source for two outbreaks of Shigella gastroenteritis.

Simultaneous outbreaks of Shigella sonnei gastroenteritis occurred in October 1983 at two Texas university campuses 60 miles (96 km) apart. There were no common food handlers, recreational activities, water sources or swimming areas to explain the introduction of Shigella at both campuses. However, tossed salads were found to be associated with illness at both campuses. The investigation disclosed that both schools had received produce shipments from the same company during the week preceding these outbreaks. Shigella isolates from cases at both universities, sent to the Centers for Disease Control for plasmid analysis and colicin typing, were found to be identical. The same organism was evidently not a frequent cause of shigellosis within a 160-mile (256 km) radius of these universities since only 19% of control isolates chosen from this area were identical to the type which caused these outbreaks. This is the first report of two related outbreaks of shigellosis that were caused by a contaminated food source and not by a food handler. Simultaneous foodborne outbreaks of shigellosis should trigger a search for potential contamination at every step of food handling from farm to kitchen.

Disease Outbreaks↗
PubMed1985

Effects of passive smoking on ischemic heart disease mortality of nonsmokers. A prospective study.

The mortality attributable to ischemic heart disease as a result of cigarette smoking is greater of a community of older adults in southern California, the authors tested the hypothesis that nonsmoking women exposed to their husband's cigarette smoke would have an elevated risk of fatal ischemic heart disease. Married women aged 50-79 years who had never smoked cigarettes (n = 695) were classified according to the husband's self-reported smoking status at entry into the study: never, former, or current smoker. After 10 years, nonsmoking wives of current or former cigarette smokers had a higher total (p less than or equal to 0.05) and age-adjusted (p less than or equal to 0.10) death rate from ischemic heart disease than women whose husbands never smoked. After adjustment for differences in risk factors for heart disease, the relative risk for death from ischemic heart disease in nonsmoking women married to current or former cigarette smokers was 14.9 (p less than or equal to 0.10). These data are compatible with the hypothesis that passive cigarette smoking carries an excess risk of fatal ischemic heart disease.

Aged↗
PubMed1984

Is borderline fasting hyperglycemia a risk factor for cardiovascular death?

The majority of previously reported studies of borderline hyperglycemia as a risk factor for cardiovascular disease are based on post-challenge glucose levels, are limited to men, and show either no significant association or a possible threshold effect. In order to determine whether fasting plasma glucose (FPG) in the normal range (less than 140 mg/dl) predicts mortality, we prospectively studied a geographically defined Southern California community of 3625 nondiabetic men and women aged 40-79, 99.5% of whom were followed for 9 years. Levels of FPG were significantly associated with levels of most heart disease risk factors. After adjusting for these risk factors, FPG, analyzed either as a continuous or categorical variable, was independently and significantly associated with all-cause, cardiovascular and ischemic heart disease mortality in men in proportional hazard models. An excess of all-cause mortality with the highest levels of FPG (130-139 mg/dl) was the only statistically significant association seen in women. The absence of a significant linear association in women may reflect true sex differences or a lack of power owing to the relatively small numbers of deaths in women. The independent linear glucose mortality association in men found here differs from previous studies, and may reflect both the larger number of events and the use of FPG, which has less intra-individual variability and less potential for misclassification bias than post-challenge glucose.

Adult↗
PubMed1984

Ischemic heart disease risk factors after age 50.

Previous studies have suggested that the predictive power of the three major risk factors for ischemic heart disease (hypertension, hypercholesterolemia, and cigarette smoking) decreases sharply with age. We re-examined this question in a cohort of 3187 adults aged 50-79 with baseline evaluation in 1972-1974 who were followed at least 9 years during a period of a marked decline in national cardiovascular disease mortality. Four-hundred and eighty-three subjects died, 123 of ischemic heart disease. Predictors of outcome were studied separately in younger (age 50-64) and older (age 65-79) groups. After multivariable adjustment for potential confounders using Cox proportional hazards models, cholesterol retained a significant independent predictor of ischemic heart disease mortality at older ages for both men and women. Cigarette smoking and hypertension were significantly related to all-cause but not to ischemic heart disease mortality in this older population. We suggest that the persistence of cholesterol as an independent predictor of fatal ischemic heart disease in old age may reflect the consequences of a shift in risk factor distribution with deferred selective mortality in a cohort with an overall favorable risk factor status.

Age Factors↗
PubMed1984

Is an educated wife hazardous to your health?

Three of four previous studies have suggested that men whose wives are more educated than they are at increased risk of coronary heart disease, defined to include angina pectoris, but one study of coronary heart disease exclusive of angina failed to show an association with educational discordance. In this study, the authors used data from a cohort of 1698 spouse pairs aged 45-79 years who were followed prospectively for nine years to determine whether discordance for education was predictive of ischemic heart disease death. In this upper-middle-class population, men with more educated wives tended to be older, had a lower socioeconomic status, and higher blood pressure levels. A significant increase in risk of all-cause and ischemic heart disease death was seen in men whose wives were more educated than they, compared with men whose wives were less educated. This risk was highest for the least educated men with the most educated wives, and was not totally explained by differences in age, socioeconomic status, blood pressure, or other risk factors. These data support a causal role for status incongruity and fatal ischemic heart disease.

Aged↗
PubMed1984

Interaction between cigarette smoking and diabetes mellitus in the prediction of death attributed to cardiovascular disease.

Previous studies have shown that the increased risk of cardiovascular disease in adults with diabetes is independent of heart disease risk factors and have suggested that the effect of these risk factors is similar in diabetics compared with nondiabetics. To determine whether there was interaction between diabetes and the classic heart disease risk factors (cholesterol, blood pressure, and cigarette smoking) in the prediction of cardiovascular death, the etiologic fraction due to interaction was assessed in a nine-year follow-up of 2,620 older Caucasian adults (60-79 years) who resided in Rancho Bernardo, California, 8.7% of whom had diabetes by history of fasting hyperglycemia. In these older adults, the frequency of categoric hypertension, hypercholesterolemia, or current cigarette smoking did not differ significantly among diabetics compared with nondiabetics. Overall, the age-adjusted relative cardiovascular mortality risk among diabetics was similar to that in nondiabetics for all risk factors except cigarette smoking, for which the relative risk for diabetics was 2.2 compared with 1.2 for nondiabetics. High cholesterol and systolic blood pressure levels showed no interaction with diabetes, but cigarette smoking had a large and significant interaction with diabetes, such that an estimated 65% of the cardiovascular disease deaths among diabetics could be attributed to the interaction of diabetes and cigarette smoking. If confirmed, these data have important implications for the prevention of cardiovascular death in older diabetics.

Aged↗
PubMed1983

Dairy products, calcium, and blood pressure.

The previously reported inverse association of dietary calcium intake and blood pressure levels was examined in a Southern California community, in order to determine whether this association was independent of age, obesity, and alcohol consumption. In the total population significantly less calcium intake from milk was reported in hypertensive versus normotensive men (but not women) and the association was independent of age and obesity. In a 23% subsample of men from this cohort the effect of total dietary calcium intake from all dairy products was estimated from a 24-h dietary recall. Again hypertensive men consumed significantly less calcium than normotensives. In men, both systolic and diastolic blood pressure levels were inversely associated with calcium intake from dairy products. After controlling for age, obesity, and alcohol, diastolic blood pressure was negatively and significantly associated with total calcium intake from dairy products, while systolic blood pressure was similarly associated with whole milk calcium alone. Although these data are cross-sectional, they suggest that some component of dairy products, probably calcium, exerts a protective effect against hypertension, and are compatible with the protective effect of calcium reported in hypertension-prone rats.

Adult↗
PubMed1983

Clustering of heart disease risk factors in diabetic compared to nondiabetic adults.

In a population-based study conducted by the Lipid Research Clinic between 1972 and 1974, the authors investigated the frequency and clustering of five heart disease risk factors--cholesterol, triglycerides, systolic blood pressure, obesity, and cigarette smoking--in 347 diabetic and 2285 euglycemic nondiabetic adults aged 35 to 79 years. Diabetics were more likely than nondiabetics to have high risk factor levels, although excesses for cholesterol and cigarette smoking were not statistically significant. Subjects at or above the 70th or 90th percentiles for one risk factor were more likely to be at or above these percentiles for other risk factors, and this clustering of heart disease risk factors was more common among diabetics than nondiabetics. Excess clustering in diabetics persisted after controlling for obesity and when only cholesterol, blood pressure, and cigarette smoking were analyzed. Clustering was more marked in women than in men. This may explain some of the excess risk of heart disease in female compared to male diabetics, which has been reported by others.

Adult↗
PubMed1983

The sex differential in mortality from all causes and ischemic heart disease.

The sex differential in mortality from all causes and ischemic heart disease is examined in an upper-middle class Caucasian community of 3516 adults in southern California, who were followed for a minimum of seven years. The influence of several demographic, behavioral, and biologic risk factors is simultaneously controlled for by means of a multiple logistic analysis. Risk factors include age, marital status, education, cigarette smoking, cholesterol, systolic blood pressure, fasting plasma glucose, and obesity. Both the prevalence and relative mortality risk associated with several risk factors differ by sex. Adjustment decreases the sex differential for mortality from 1.7 to 1.3 for all causes and from 4.8 to 2.4 for ischemic heart disease. When analysis is limited to healthy men and women, the adjusted sex differential in mortality is 1.2 for all causes and 2.0 for ischemic heart disease. Findings of this study are compared with two other population-based studies.

Adult↗