Biomedical subjects
Publications and source records attributed to E Suarez.
Screening of plants from South America for antitubercular activity and subsequent assay-guided fractionation resulted in the isolation and characterization of several pentacyclic triterpenoids. The MIC values of 22 triterpenoids were determined using the radiorespiratory BACTEC assay and range from 8 microM to above 128 microM. The structure-activity relationships are discussed.
New advances in the diagnosis and treatment of HIV infection continue to propel changes in public understanding of HIV infection and the administration of public health law. Over the past decade, New York State has moved from a policy of blind newborn screening for seroprevalence data to mandatory HIV testing as part of the statewide Newborn Screening (NBS) Program. A new statewide program of expedited HIV testing (48-hr turnaround results) of pregnant women and newborns (whose HIV status is unknown at the time of delivery) began in the summer of 1999. To better understand the impact this program might have on the patients who receive health care at Lincoln Medical and Mental Health Center (Lincoln Hospital), we evaluated our experience with the current NBS program prior to inauguration of the new expedited testing program. We evaluated the NBS program from February 1, 1997, to January 31, 1999, including total number of HIV-exposed/infected infants born, mother's HIV status (if known) at the time of delivery, amount of time between blood sampling and return of the test results to the Hospital, and medical follow-up of infants with positive newborn screening test results. This was a retrospective study of the NBS registry and the medical records of patients who receive primary health care from the Pediatric Immunology Service of the Department of Pediatrics at Lincoln Hospital. One hundred and four newborns were identified with positive-HIV antibody (HIV-Ab-positive), and 13 (12.5%) were confirmed to be HIV-infected by positive polymerase chain reaction (PCR) test of viral DNA. Sixty-five (62.5%) of the newborns with positive NBS screening test results were born to mothers who were known to be HIV-infected prior to delivery; 39 (37.5%) were unanticipated. Four (30%) of the 13 HIV-infected babies were born to mothers who were known to be HIV-infected prior to delivery, and 9 (70%) were born to mothers whose HIV status was unknown at the time of delivery. Eighty percent (80%) of HIV-Ab-positive infants continued to receive follow-up care at Lincoln Hospital. Relocation to other health-care facilities occurred as a result of parental choice or due to foster care placement. No babies were "lost" from the NBS program. The average time between sampling and receipt of results for all blood tests was 16 days (range 10 to 141). Nearly 40% of newborns who acquired HIV infection from their mothers were unanticipated because the mother's HIV status was unknown at the time of delivery. These unanticipated HIV-infected infants represent missed opportunities for prevention of maternal-to-child transmission of HIV infection and early therapeutic intervention for HIV-infected infants. The new expedited HIV-testing program for New York State will facilitate early diagnosis, prevention and treatment of the HIV-exposed/infected infant for whom maternal HIV status is unknown at the time of delivery.
A new linear gramicidin analog bearing a biotinyl group grafted on C-terminal part was designed to study ligand-receptor interactions. The C-terminal alcohol in the native peptide was first replaced by an amino group. Then the peptide was synthesized on a polystyrene resin functionalized by the 2-chlorotrityl chloride following a biotinylation performed in solution. This new N'-biotinyl-(EDA)15-Gramicidin A was reconstituted in planar lipid bilayers and exhibited channel activities similar to those of natural gramicidin, with unitary conductance value about 30 ps in 1 M KCl. Furthermore this ionophore activity was quenched by addition of streptavidin in the surrounding medium. Our system is an outstanding tool for monitoring ligand-receptor interactions and could be used for designing a new biosensor.
Bioactivity-guided fractionation of the petroleum ether extract of Azorella madreporica Clos has led to the isolation of the novel, antitubercular mulinane diterpenoid 1. The structure has been elucidated on the basis of its 1D and 2D NMR spectra and by comparison with mulinolic acid 2 and a dehydration product 3 obtained from 1. The MIC of 1 for growth inhibition of the H37Rv strain of Mycobacterium tuberculosis was determined as 20 microg/mL. LC-MS and NMR have suggested the presence of this new compound in four other species of Azorella.
PURPOSE: To evaluate the effectiveness of two-incision radial keratotomy (RK) in correcting low-magnitude refractive myopic astigmatism. SETTING: Two clinical study sites, one in St. Louis, Missouri, USA, the other in Caracas, Venezuela. METHODS: Fifty-seven eyes of 43 patients with low-magnitude myopic astigmatism had two-incision RK at one of two clinical study sites. In the initial phase of this series, 10 eyes with amblyopia at the 20/30 level had surgery at one center. Refractive keratotomy was performed with the radial incision placed in the plus cylinder axis of refraction. This axis was verified as the meridian of greatest corneal curvature by standard keratometry and computer-assisted corneal topographic analysis. Two eyes received a second operation (enhancement). RESULTS: Mean follow-up was 11.1 months (range 6 to 12 months). Mean preoperative and postoperative myopic spherical equivalent measured -1.42 diopters (D) +/- 0.51 (SD) and -0.14 +/- 0.39 D, respectively; the mean reduction was 1.28 +/- 0.59 D (P = .0001). Mean preoperative and postoperative refractive astigmatism was 1.41 +/- 0.45 D and 0.48 +/- 0.33 D, respectively (P = .0001). Mean preoperative and postoperative keratometric astigmatism was 1.26 +/- 0.54 D and 0.31 +/- 0.35 D, respectively, a mean reduction of 0.95 D (P = .0001). The surgical meridian was flattened by an average of 2.06 D by keratometry and the orthogonal meridian, by an average of 1.10 D. Preoperative uncorrected visual acuity (UCVA) was 20/40 or better in five (9%) eyes (range counting fingers to 20/40). Postoperative UCVA acuity was 20/40 or better in all eyes (mean acuity 20/25). In the nonamblyopic subgroup mean postoperative UCVA was 20/24. CONCLUSIONS: A limited number of radial incisions placed in the topographically confirmed axis of greatest curvature are effective in the treatment of low-magnitude myopic astigmatism.
In this intervention, participants design and implement an HIV/AIDS prevention project for Mexican homosexual men. The intervention is consistent with, and contributes to, empowerment theory because it enhances collective action, provides opportunities to develop knowledge and skills, creates needed resources, and includes shared control with professional and among participants. The intervention described provides an illustration of an empowering process and distinguishes itself from empowerment outcomes. An evaluation of the project is also described, but the outcomes were HIV/AIDS-related behaviors rather than psychological empowerment of the participants. The results suggest that the participants' HIV/AIDS knowledge and preventive behavior improved when compared to individuals who did not participate in the intervention. In addition, the intervention generated community change initiated by participants. Implications for designing interventions using an empowerment approach are discussed.
Diurnal variations in urinary norepinephrine, epinephrine, cortisol, and self-reported mood states were examined in 101 employed women. Urine was collected on 2 consecutive workdays at 3 time periods: (1) overnight, (2) daytime, and (3) evening. Self-reports of 14 mood states were combined to correspond with the urinary collection periods. Factor analyses revealed 3 mood factors: Pressured (rushed, busy, stressed, hassled, and tense), Distressed (afraid, depressed, bored, and nervous), and Contented (satisfied, thoughtful, excited, and calm). The Distressed factor was significantly associated with norepinephrine excretion (p <.001). The Pressured factor was significantly associated with cortisol, epinephrine, and norepinephrine excretion (p <.001) independent of age, ethnicity, marital status, parental status, department within the company and activity level. Secretion of urinary hormones and the Pressured factor followed the same diurnal pattern. Specifically, as women's self-ratings of feeling pressured initially increased and then decreased over the course of the workday, urinary hormones also peaked and then dropped. Once time of day was statistically controlled, however, the mood factors were no longer significantly related to the urinary hormones.
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The serum protein binding of itraconazole and fluconazole, new azole antifungal agents, has been investigated in vitro, in serum from healthy volunteers and from patients with cancer. Protein binding was determined by ultrafiltration. Concentrations of both alpha 1-acid glycoprotein (AAG) and albumin (HSA) were measured in all serum samples. The serum protein binding of itraconazole was reduced in patients (96.02 +/- 1.41% vs 97.25 +/- 0.54%; p < 0.01) with respect to healthy volunteers. In contrast, fluconazole protein binding was increased in the same group of patients (22.96 +/- 3.60% vs 13.30 +/- 2.58%; p < 0.01). HSA levels in cancer patients were significantly decreased (p < 0.01) and AAG levels were found to be significantly elevated in patients with respect to control subjects (p < 0.05). A significant linear relationship between the bound/unbound concentration ratio of itraconazole and HSA (r2 = 0.3340; p < 0.01) was found. Similarly, a significant relation was established between the bound/unbound concentration ratio of fluconazole and AAG levels (r2 = 0.2235; p < 0.05). Thus, a weak association between the binding of these drugs and serum protein levels has been observed. It is concluded that both antifungal drugs show different protein binding behaviour in cancer patients.
The serum protein binding of itraconazole and fluconazole, new triazole antifungal agents, has been investigated in vitro in the serum of healthy volunteers and in patients with chronic renal failure (predialysis). Protein binding was determined by ultrafiltration. Concentrations of both alpha 1-acid glycoprotein (AAG) and albumin were measured in all serum samples. The protein binding of itraconazole showed no significant changes in patients with chronic renal failure when compared to healthy volunteers (96.64 +/- 0.99% vs. 96.85 +/- 0.33%). In contrast, fluconazole protein binding was significantly increased in the same patients (22.91 +/- 6.15% vs. 12.51 +/- 2.37%; p < 0.001). In addition, whereas albumin levels in the latter patients were significantly decreased (p < 0.001), their AAG levels were found to be significantly elevated with respect to control subjects (p < 0.001). While no correlation was established between itraconazole protein binding and albumin or AAG concentrations, a significant correlation was found between fluconazole protein binding and AAG levels (r = 0.72; p < 0.001). Fluconazole protein binding was found to be independent of albumin concentrations. In vitro carbamylation of serum protein with potassium cyanate caused no changes in the protein binding of fluconazole or itraconazole. We conclude that the binding of itraconazole by serum proteins is not altered in diseases involving changes of AAG or albumin concentrations. However, fluconazole protein binding may be altered in disease states associated with increased AAG concentrations.
Little knowledge exists about AIDS and Human Immunodeficiency Virus (HIV) infection among Latin American gay males. In Latin America, sexual transmission from man to man is the leading cause of HIV infection. In Mexico, which ranks third in number of AIDS cases in the Americas, more than three-quarters of the cases are due to sexual transmission; among these cases, 35% and 23.7% are due to homosexual and bisexual male practices, respectively. A sample of 200 individuals from Juarez, Mexico, a city on the U.S. border, was interviewed. Information about their AIDS knowledge, sexual behavior, and condom use was obtained. Factory workers and individuals who meet sexual partners in the streets reported more sexual partners than workers in service or professional occupations and those who meet their partners in bars and discos. Number of sexual partners and respondents' age were inversely associated with condom use. Implications for HIV prevention are discussed.
A total of 136 incident intestinal type gastric cancer cases and 151 age-comparable population controls were interviewed in Puerto Rico about their dietary habits with special emphasis on dietary salt consumption. All interviews were conducted at home using a quantitative dietary frequency instrument. The weekly intake of foods was estimated from the reported frequency of consumption and portion size according to a food model. The dietary salt exposure was estimated from the intake of nine selected food items which are highly salted food items commonly consumed in Puerto Rico. A strong (odds ratio [OR] = 3.34) and statistically significant (P < 0.001) unadjusted difference was found between cases and controls regarding dietary salt exposure. A statistically significant dose response for the index of salt exposure and gastric cancer was also found. The association remained positive and statistically significant after simultaneously adjusting for the confounding effects of sex, education and cigarette smoking.
This study was designed to determine whether gastroduodenal ulcer influences propranolol absorption. Eleven patients with peptic ulcer disease and eight healthy subjects received 80 mg of propranolol orally. Serum propranolol levels were measured with high-performance liquid chromatography. Ulcer patients showed a significant decrease in mean peak concentration of propranolol (90 +/- 12 ng/ml versus 151 +/- 23 ng/ml) (p < 0.025), in the absorption constant (1.43 +/- 0.21 h-1 versus 0.96 +/- 0.12 h-1) (p < 0.05), and in the area under concentration-time curve (802 +/- 129 ng/ml.h versus 492 +/- 73 ng/ml.h) (p < 0.05). No significant difference was seen in drug effect on the heart at 90 min. We conclude that propranolol is absorbed more slowly in ulcer patients than in healthy subjects, but this delay has no clinical effect after a single dose.
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The interaction between nimodipine, a calcium channel blocker, used for the treatment of subarachnoid haemorrhage, and atracurium, was studied in rabbits. An intravenous dose of 0.1 mg.kg-1 of nimodipine given over 3 min caused a potentiation of the neuromuscular blocking action of atracurium (administered at an infusion rate of 7.5 micrograms.kg-1.min-1), measured on the indirectly stimulated tibialis-anterior muscle of the animal. (ED50)inf and (ED95)inf were significantly reduced (30.7% and 23.3%) in nimodipine-treated animals (P less than 0.05 and P less than 0.02, respectively). No changes were observed in recovery rate.
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Pressure sores are a frequent complication of spinal cord injury (SCI) and are assumed to result from insufficient rotation following admission to the acute care unit. The likelihood of pressure sores occurring before admission to the nursing unit is not usually recognized. This study attempts to determine whether pressure sores are associated with prolonged immobilization in the early post-injury period, before admission to the acute care ward, and to identify other etiological factors relating to evacuation, transportation, and emergency room treatment. Thirty-two SCI patients were studied, 16 of whom developed sores in the hospital, and 16 who did not. Excluding five patients who failed to recall their immediate post-injury care, none of the remaining 14 patients with sores recalled being turned within two hours of injury; all 13 patients without sores said that they were rotated within two hours. Almost all patients said they were first turned on the hospital ward by a nurse. Whereas most of those without sores took less than two hours to reach the ward, most of those who later developed sores took three hours or longer.