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Biomedical subjects

L Lopez

Publications and source records attributed to L Lopez.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effects of serotonin and fluoxetine on blood glucose regulation in two decapod species.

One of the best known crustacean hormones is the crustacean hyperglycemic hormone (CHH). However, the mechanisms involved in hormone release in these animals are poorly understood, and thus constitute the central objective of the present study. Different groups of crustaceans belonging to diverse taxa (Chasmagnathus granulata, a grapsid crab and Orconectes limosus, an astacid) were injected with serotonin, fluoxetine, or a mixture of both, and glycemic values (C. granulata and O. limosus) and CHH levels (O. limosus) were determined after 2 h in either submerged animals or animals exposed to atmospheric air. Both serotonin and fluoxetine caused significant hyperglycemia (P<0.05) after injection into the blood sinus of the two species, an effect enhanced after exposure to atmospheric air. In C. granulata blood glucose increased from 6.1 to 43.3 and 11.4 mg/100 ml in submerged animals and from 5.7 to 55.2 and 22.5 mg/100 ml in air-exposed animals after treatment with serotonin and fluoxetine, respectively. In O. limosus the increases were from 1.2 to 59.7 and 135.2 mg/100 ml in submerged animals and from 2.5 to 200.3 and 193.6 mg/100 ml in air-exposed animals after treatment with serotonin and fluoxetine, respectively. Serotonin and fluoxetine also caused a significant increase in the circulating levels of CHH in O. limosus, from 11.9 to 43 and 45.7 fmol/ml in submerged animals and from 13.2 to 32.6 and 45.7 fmol/ml in air-exposed animals, respectively, thus confirming their action as neuroregulators in these invertebrates.

Animals↗
PubMed2001

Listeriosis: an emerging food-borne disease.

Listeriosis is a serious disease acquired by ingestion of foods contaminated with Listeria monocytogenes. Special populations at risk are individuals who are immunocompromised to some extent. The most common clinical findings include meningitis, septicemia, encephalitis, and intrauterine/cervical infections. Food related listeriosis is an unusual occurrence but it is now being thought of as a new, and emergent illness. Numerous types of food products have been implicated in listeriosis infections, but of particular concern are ready to eat products such as lunchmeats, hotdogs, ham/chicken salad, sausages, and roast beef. However, to ensure food safety, there are several methods employed to detect L. monocytogenes in food products and the severity of listeriosis warrants stringent guidelines in food processing facilities. Nevertheless, proper food preparation and handling must be emphasized and individuals who are at an increased risk for the disease must be apprised on how to prevent the occurrence of infection.

Food Microbiology↗
PubMed2000

Reduction of high-risk behaviors among incarcerated youths: a challenge in prevention.

The adolescent population in America is at increasing risk for acquiring the human immunodeficiency virus (HIV) that causes AIDS (CDC, 1998; 1996; 1994; 1993). Although the total number of reported AIDS cases among adolescents 12 to 19 years of age is, thus far, fairly small, the identified caseload in this age group has increased by over 40% during one year alone. In fact, one-fifth of all reported AIDS cases occur among persons 20 to 29 years of age. Many of these young adults contracted HIV infections as teenagers (CDC, 1996). But the trend is changing. In fact, among younger youths, especially those of African heritage, the infection rates are rapidly increasing (CDC, 1999; CDC, 1998). These increases will require focused attention by all health professionals, and public policy officials (Lai, Tsai, Hardy, 1997; Porter, Oakley, Guthrie & Killion, 1999). The purpose of this current study was to describe risk-related behaviors of incarcerated youths that are significant factors when planning community-based programs for HIV/AIDS prevention. Several research questions were generated in this regard and tested. Several significant findings emerged from the data that indicate that African-American youths incarcerated are at greater risk for development of HIV/AIDS than their other ethnic counterparts.

Adolescent↗
PubMed1999

Synchronized approximately 15.0-35.0 Hz oscillatory response to spatially modulated visual patterns in man.

When suitably stimulated, neurons in the striate visual cortex of cats fire in bursts at 20-60 Hz and the membrane potential oscillates rhythmically in the same frequency range and in phase. These oscillations reflect intrinsic properties of mammalian neurons, occur in coherent spatial patterns that depend on the segregation and stimulus selectivity of stimulated cells, and mediate in long-range synchronization across columns and over large cortical areas of cells responding to the same stimulus property/properties. The pool of activated neurons may be adequate in size to drive cellular oscillations into local fields and mass responses. Accordingly, stimulus-dependent oscillatory activity in the same frequency range was described in man after contrast stimulation. Our results describe oscillatory potentials at approximately 15.0-35.0 Hz that in man are (partly) independent from, and anticipate the occurrence of, the conventional low-frequency visual response evoked by transient, foveal stimulation with spatially-modulated patterns.

Adult↗
PubMed1998

Survival in neonatal biventricular repair of left-sided cardiac obstructive lesions associated with hypoplastic left ventricle.

Patients with left ventricular hypoplasia and left-sided heart obstructive lesions other than critical aortic stenosis may be inappropriately subjected to single ventricular repair because their assessment is based on faulty qualitative evaluations or on quantitative methods developed for critical aortic stenosis. Patients with left ventricular hypoplasia and left-sided heart obstructions other than critical aortic stenosis successfully underwent biventricular repair despite "failing" to pass established criteria for critical aortic stenosis.

Aortic Coarctation↗
PubMed1998

Hepatotoxicity of the drinking water disinfection by-product, dichloroacetic acid, in the medaka small fish model.

Recent studies have shown that dichloroacetic acid (DCA), a by-product of chlorination of public water supplies, is carcinogenic to both rats and mice. However, conflicting data have left the mechanism of DCA carcinogenicity, vital to assessment of human health risk, unclear. Elucidation of this mechanism in another animal model at a different phyletic level than rodents would advance the risk assessment process for government agencies concerned with regulation and provision of safe drinking water. The Japanese medaka (Oryzias latipes), a well characterized small fish model, is being used increasingly for carcinogenicity testing because of its low cost, ease of maintenance and carcinogen sensitivity. In this study, 6-week-old medaka were exposed to diethylnitrosamine (DEN, a known initiator), followed by continuous exposure to 0.5 or 2.0 g/l DCA in the ambient water, over a 4 week period. At both exposure concentrations, changes in the liver included marked hepatocellular cytoplasmic vacuolation, cytomegaly, karyomegaly, nuclear atypia and multifocal areas of hepatocellular necrosis and loss as early as week two of DCA exposure. The majority of the hepatocellular cytoplasmic vacuoles were shown by periodic acid Schiff (PAS) staining to contain large amounts of glycogen. These elevated glycogen levels may reflect a disruption in the enzyme pathways for glycolysis. The total cellular changes seen in this short-term exposure regimen are compatible with preneoplastic changes seen in rats and mice exposed to DCA. The results of this study strengthen the role of the Japanese medaka as a suitable species in carcinogenicity testing as well as its implementation in the risk assessment process for DCA across several phyletic levels.

Animals↗
PubMed1998

Magnetic source imaging and reactivity to rhythmical stimulation in tuberous sclerosis.

The present study combined functional magnetoencephalography (MEG) and anatomical magnetic resonance imaging (MRI) information in three patients affected by tuberous sclerosis and partial epilepsy. MEG recordings were performed during both spontaneous and visual evoked activity. The former showed a large variety of complexes whose spatial and temporal distribution suggested different neuronal populations acting simultaneously in the same focal district. When these data were integrated with MRI images (magnetic source imaging, MSI) there was agreement in the definition of tubers and extension of the epileptogenic area. Furthermore, cortical reactivity to rhythmical stimulation was studied with trains of visual stimuli according to a recently proposed frequency responsiveness procedure (FRP). As compared to normal controls, a large 6 Hz activity was observed during the pause after a non-resonant stimulation. This altered resonance property may indicate a disturbed primary sensory processing notwithstanding a preserved associated processing. These results show that neuronal malfunctioning in tuberous sclerosis complex patients may not be restricted to the area of cortical tubers, but can also affect functionally correlated regions.

Adolescent↗
PubMed1998

Characterization of cry genes in a Mexican Bacillus thuringiensis strain collection.

Mexico is located in a transition zone between the Nearctic and Neotropical biogeographical regions and contains a rich and unique biodiversity. A total of 496 Bacillus thuringiensis strains were isolated from 503 soil samples collected from the five macroregions of the country. The characterization of the strain collection provided useful information on the ecological patterns of distribution of B. thuringiensis and opportunities for the selection of strains to develop novel bioinsecticidal products. The analysis of the strains was based on multiplex PCR with novel general and specific primers that could detect the cry1, cry3, cry5, cry7, cry8, cry9, cry11, cry12, cry13, cry14, cry21, and cyt genes. The proteins belonging to the Cry1 and Cry9 groups are toxic for lepidopteran insects. The Cry3, Cry7, and Cry8 proteins are active against coleopteran insects. The Cry5, Cry12, Cry13, and Cry14 proteins are nematocidal. The Cry11, Cry21, and Cyt proteins are toxic for dipteran insects. Six pairs of general primers are used in this method. Strains for which unique PCR product profiles were obtained with the general primers were further characterized by additional PCRs with specific primers. Strains containing cry1 genes were the most abundant in our collection (49.5%). Thirty-three different cry1-type profiles were identified. B. thuringiensis strains harboring cry3 genes represented 21.5% of the strains, and 7.9% of the strains contained cry11 and cyt genes. cry7, cry8, and cry9 genes were found in 0.6, 2.4, and 2.6% of the strains, respectively. No strains carrying cry5, cry12, cry13, cry14, or cry21 genes were found. Finally, 14% of the strains did not give any PCR product and did not react with any polyclonal antisera. Our results indicate the presence of strains that may harbor potentially novel Cry proteins as well as strains with combinations of less frequently observed cry genes.

Animals↗
PubMed1998

Clinical outcome in diffuse large B-cell lymphoma is dependent on the relationship between different cell-cycle regulator proteins.

PURPOSE: The goal of this work was to perform a comprehensive exploration of the relationship between the clinical outcome of diffuse large B-cell lymphoma (DLBCL) and the expression of a panel of tumor suppressor and oncogenic proteins, which includes some cell-cycle regulator proteins involved in the p53 pathway. PATIENTS AND METHODS: To this end, we collected the clinical data of 141 patients with DLBCL and immunohistochemically analyzed diagnostic tumoral tissue from each patient for the presence of Ki67 (MIB1, Immuno-tech, Marseille, France), bcl2, p53, p21/WAF1, MDM2, and retinoblastoma (Rb) proteins. RESULTS: The results show that several proteins are associated with some of the clinical traits analyzed. Multivariate analysis showed that an extended overall survival (OS) time was associated with low growth fraction, high Rb protein, and low MDM2 expression, as well as with known clinical parameters. The probability of inducing a complete remission (CR) was only associated with clinical parameters, although univariate study showed that a low growth fraction was associated with a higher probability of inducing a CR. Univariate study of disease-free survival (DFS) showed that tumors with high bcl2 expression and nodal origin have a shorter DFS time, although multivariate study only confirmed the adverse effect of bcl2 expression. CONCLUSION: Taking all these results into consideration, it seems that although the overall outcome for patients with DLBCL is decided by a combination of different clinical and biologic variables, the expression of some of these cell-cycle regulator proteins appears to be specifically associated with the different clinical features of tumors.

Adolescent↗
PubMed1998

A project to reduce the burden of diabetes in the African-American Community: Project DIRECT.

Project DIRECT (Diabetes Interventions Reaching and Educating Communities Together) is the first comprehensive community diabetes demonstration project in the United States in an African-American community. This article describes its intervention components and evaluation design. The development and implementation of Project DIRECT has included the community since the project's beginning. Interventions are targeted in three areas: health promotion (improving diet and physical activity levels), outreach (improving diabetes awareness, detection of undiagnosed diabetes, and ensuring that persons with diabetes who are not receiving continuing diabetes care are integrated into the health-care system), and diabetes care (improving self-care, increasing access, and improving the quality of diabetes preventive care received within the health-care system). Evaluation will be internal (conducted by Project DIRECT staff to assess process outcomes in persons directly exposed to each specific intervention) and external (review of outcomes to assess the impact of the multi-intervention program at the level of the entire community). Because diabetes exacts a disproportionate toll among African Americans, the findings from this project should aid in developing strategies to lessen the burden of this disorder, particularly among minority populations.

Black or African American↗
PubMed1997

Clinical implications and possible association of malposition of the branch pulmonary arteries with DiGeorge syndrome and microdeletion of chromosomal region 22q11.

We describe a series of 10 patients with malposition of the branch pulmonary arteries (4 patients with crossing [crossed pulmonary arteries] and 6 patients without crossing), 2 of whom had a short main pulmonary artery segment that resulted in iatrogenic right pulmonary artery stenosis after pulmonary artery band placement. DiGeorge syndrome was seen in 5 patients and 4 had microscopic deletion of chromosomal region 22q11.

Adolescent↗
PubMed1997

Drug quantitation on a benchtop liquid chromatography-tandem mass spectrometry system.

The specificity and selectivity of LC-MS-MS is illustrated to explain why LC-MS-MS has become the method of choice for quantitation within the pharmaceutical industry. Two assays are described that demonstrate the facility with which new ion trap technology can utilize the selectivity and sensitivity of LC-MS-MS to quantitate trace level components within complex matrices, in particular human plasma. One assay undergoes a validation procedure and demonstrates the utility of this new technology for drug quantitation within a regulated environment.

Calibration↗
PubMed1997

Osteoarticular and muscle infectious lesions in patients with the human immunodeficiency virus.

Between 1988 and 1995, 1832 HIV positive patients were evaluated in our institution. We studied the epidemiologic, immunologic and bacteriologic data, laboratory tests, and X-Ray films in those with musculoskeletal infection. We reviewed twenty-one cases of musculoskeletal infection in twenty patients aged 23-35 years (mean 28,6 years, M:F= 15:5). In all of them risk factor for HIV was intravenous drug abuse. The number of CD4 positive lymphocytes ranged from 0,003 to 0,5 10(9)/l. Staphylococcus aureus was the organism responsible of the infection in twelve cases, all active intravenous drug abusers at the time the diagnosis was done. The remaining causative agents were: Mycobacterium tuberculosis (3 cases), Candida albicans (2 cases), Salmonella subgroup 1 (1 case), Neisseria gonorrhoeae (1 case), Pseudomona aeruginosa (1 case) and Streptococcus agalactiae (1 case). Fifteen infections were diagnosed between 1988 and 1991 and 6 between 1992 and 1995. Musculoskeletal infectious lesions in HIV positive patients in our country are related in the majority of cases to intravenous drug abuse. In the last four years due to a National medical health care plan conducted to educate this group of people the number of musculoskeletal infections is decreasing.

AIDS-Related Opportunistic Infections↗
PubMed1997

Magnetically recorded oscillatory responses to luminance stimulation in man.

Fast-frequency (ca. 100-110 Hz) oscillatory potentials superimposed on waves N2 and P2 of conventional broad-band VEP were magnetically recorded in man from occipital locations in response to monocular transient flash stimulation with full-field flashes (3.5 cd.s.m-2 intensity) and in spots (1, 1.5, or 2.0 cm in diameter). These oscillations proved replicable between- and within-subject and were phase-locked to retinal oscillatory potentials, with maximum correlation at approximately 35 ms and mean delay (as measured between the first measurable peaks) of 27.4 +/- 1.6 ms. When stimuli were in spots at increasing eccentricity (5, 15, or 25 degrees) from foveal fixation, broad-band VEP were recorded regardless of diameter and eccentricity of spot, whereas oscillatory responses were not detectable at eccentricity of, or greater than, 15 degrees. This observation suggests that broad-band VEP and the oscillatory response are generated by (partly) distinct neuronal populations and/or functional arrangements and that there is some functional connection between cortical oscillatory responses and stimulus-related events triggered in central retina.

Adult↗