Search PubMed⌕ Search

Biomedical subjects

M Sanchez

Publications and source records attributed to M Sanchez.

At least 37 records · Page 2Linked to original sources
PubMed2000

Alterations on AChE activity of the fish Anguilla anguilla as response to herbicide-contaminated water.

The inhibition of both total and specific acetylcholinesterase activities was measured in the whole eyes of the yellow eel Anguilla anguilla after exposure to the carbamate thiobencarb. In vivo assays were conducted under a constant flow-through system of thiobencarb-contaminated water (1/60 LC(50) 96 h=0.22 ppm for 96 h) followed by a recovery period in clean water (192 h more). The results indicated a measurable level of AChE activity on eyes of control eels, which resulted in a sensitive indicator of the presence of thiobencarb in the water. The pesticide induced significant inhibitory effects on AChE activity ranging from 35% in total AChE activity to 75% in specific AChE activity. Following 1 week of recovery, AChE activity in eel eyes was still different from that of controls. Specific AChE activity remained significantly depressed (35%). On the other hand, protein content in whole eyes of pesticide-treated eels did not exhibit any significant difference from control animals. It has been accepted that a minimum of 20% reduction in brain AChE would be necessary to be indicative of exposure to anticholinergic agents; however, few data are reported about this effect on sense organs.

Acetylcholinesterase↗
PubMed2000

Maternal bone lead contribution to blood lead during and after pregnancy.

We examined bone lead contribution to blood lead in a group of 311 immigrant women, 99% from Latin America, during the third trimester of pregnancy and 1 to 2 months after delivery. We measured in vivo tibia and calcaneus (heel) bone lead concentration in the postdelivery period with K shell X-ray fluorescence. Prenatal and postnatal geometric mean (range) blood lead level was 2.2 microg/dL (0.4 to 38.7) and 2.8 microg/dL (0.4 to 25.4), reflecting low current exposure. Postnatal blood lead level was significantly higher than prenatal (P<0.0001). Mean (range) tibia and calcaneus lead concentration was 6.7 microg/g (-33.7 to 62.2) and 8.4 microg/g (- 30.1 to 66.4), reflecting varying but elevated past lead exposure. Mean calcaneus lead concentration was significantly higher than mean tibia lead concentration (P = 0.055). Variance-weighted multiple regression and structural equation models showed that both calcaneus and tibia lead were directly associated with prenatal blood lead but only calcaneus lead was associated with postnatal blood lead. Increasing natural log years in the United States independently predicted decreasing calcaneus and third-trimester blood lead. The data suggest that while some exogenous lead sources and modulators of blood lead level, such as use of lead-glazed pottery and calcium in the diet, control lead exposure during and after pregnancy, endogenous lead sources from past exposure before immigration continue to influence blood lead levels in this sample.

Adolescent↗
PubMed2000

Characterization of the T cell receptor repertoire of neonatal T cells by RT-PCR and single strand conformation polymorphism analysis.

We have analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR) the individual non-germ line configurations of the T cell receptor (TCR) Vbeta chains expressed by T cells from eight individual cord blood specimens. cDNA from each cord blood was amplified using a common primer coupled with a primer specific for each of 22 variable elements of the Vbeta chain family and the amplified fragments were separated under high resolution conditions. With cDNA from adult blood (as a control), all of the TCR chains were amplified as a smear consistent with the extensive polyclonality of adult T cells. In contrast, a heterogeneous pattern of amplification was observed with cDNAs from cord blood: only 26.7+/-21.9% of the 22 Vbeta chains analyzed were amplified as a smear. The majority of them were amplified as a discrete number of bands (up to 10) (in 68.2 +/-18.7% of samples) and some of them as a single fragment (4.0+/-7.8%). Only one of the eight samples analyzed expressed the majority (72.7%) of its Vbeta chains as a smear, consistent with an adult-like TCR repertoire. In conclusion, cord blood expressed, on average, a less complex TCR repertoire than adult blood.

Adult↗
PubMed2000

Comparison of magnesium and methyldopa for the control of blood pressure in pregnancies complicated with hypertension.

OBJECTIVES: Although magnesium is now the drug of choice for the prevention of eclamptic seizures only few studies have evaluated whether magnesium may reduce blood pressure in pregnancies complicated with hypertension. METHODS: A total of 33 patients with pregnancy-induced hypertension were randomized to either magnesium or methyldopa treatment. Of these 16 received magnesium and 17 methyldopa. The treatment comprised a 48-hour magnesium infusion followed by oral magnesium tablets until 3 days after delivery or 250 mg methyldopa 4 times a day in a similar period. RESULTS: Patients treated with magnesium had 1 day after inclusion a statistically significantly lower systolic blood pressure compared to the level in the methyldopa group (138.1 +/- 11 vs. 147.6 +/- 11 mm Hg; p < 0.05), but no difference was observed in diastolic blood pressure (92.0 +/- 6.6 vs. 96.0 +/- 10.1 mm Hg; NS). From the 5th day of inclusion and until delivery both systolic and diastolic blood pressure were significantly lower in the magnesium group (p < 0.05). Including all blood pressure measurements in a single analysis showed that both systolic (138 +/- 13 vs. 148 +/- 15 mm Hg; p < 0.0001) and diastolic (92 +/- 10 vs. 94 +/- 10 mm Hg; p < 0.05) blood pressure were lower in the magnesium group compared to the methyldopa group. There was no difference between the two groups regarding gestational age at delivery, birth weight, Apgar scores and pH in umbilical cord blood. CONCLUSION: This preliminary study demonstrates that magnesium treatment lowers blood pressure in pregnancies complicated with hypertension. The effect is without any adverse effect on maternal and neonatal well-being.

Adult↗
PubMed2000

[Physical and sports activities in the history of patients treated for addictions. Report 1999 of the study sponsored by the Ministry of Youth and Sports (France)].

Early February 1999, the French Ministère de la Jeunesse et des Sports (Youth and Sports Ministry) sponsored three different studies, aiming to prevent harmful behavior in the area of sport practices among youth. Two years earlier, our health care team working with drug users published reports on the meaningfulness of intensive sports activities in the history of our patients. The present work was performed to highlight the midterm results of one of these studies, to better understand and quantify the importance of physical training in the history of a group of outpatients seen for addictive disorders and comorbid pathologies. For 20 consecutive weeks, 3,040 self-administered questionnaires were available for persons consulting 20 health centers, 2 self-help groups and a general practitioner network working in the field of alcohol or heroine abuse. One thousand one hundred and eleven questionnaires were filled out (36.1%) and returned by mail for complete analysis: 86% of the answering persons had practiced at least one sports activity or participated in physical training, 10.5% had participated in a national or international level competition, and 10.6% reported stress fractures. In the intensive sports group, 36% had used illicit drugs intravenously and 16.4% said they had already used doping substances. Only 28.4% said they experienced dependence during their period of intensive sports activities compared with 15.2% before this time, and a majority (56.4%) thereafter. Intensive sports or physical training should not be seen as a protective factor nor as a way of improving addictive behaviors. More studies are needed to evaluate individual vulnerability factors and specific harm of overtraining and to determine the exact periods when men and women participating in sports activities are likely to abuse drugs, especially at the end of their career.

Adult↗
PubMed2000

[The concept of addictology and addiction: the patient's point of view. A study on 90 persons followed for addiction].

The concept of addiction has gained recognition in French semantics, standing for a pathological condition that was formerly designated solely on the basis of specific drug abuse. We questioned 90 patients followed at there Parisian outpatient units about their understanding of the term "addiction". We also looked for signs that this term is used to federate notions since it is supposed to describe a general condition involving a large number of singular phenomena. One part of our questionnaire focused on treatment modes (several practitioners for several addictions, one institution for all addictions, specialized consultations with a practitioner other than the usual primary care physician). Our findings would illustrated areas where further details are needed in order to consider patient expectations when designing specialized care for outpatients or inpatients.

Adult↗
PubMed2000

[The Rorschach's test for heroin addicts treated by methadone: from reality to imaginary].

The aim of this study was to analyze the role of the imaginary and its link with reality among 30 subjects treated by methadone. The Rorschach test was proposed to 30 heroin addicts treated by methadone, over an average 7 months. The formal answers (used preferentially in the 30 results, though often inappropriately) and socializing landmarks involving considerable individual investment, we were able to identify two ways of working within the same protocol. The first relies most on conformity and adaptation and tries to put the imaginary aside. The second is a more projective, unorganized approach evidencing the influence of the imaginary. This specific imaginary activity could not be assimilated with the traditional "lack of fantasy" observed in heroin addicts. It would be interesting to examine the course of this approach over a longer period.

Adult↗
PubMed2000

Effects of cell banking manipulations on ex vivo amplification of umbilical cord blood.

The small volume of placental/umbilical cord blood (PUCB) collectable restricts the use of these stem cells to pediatric transplantation. To extend the use of PUCB to adult recipients, many laboratories are investigating the feasibility of ex vivo PUCB expansion. The present study analyses the effects that PUCB banking cell manipulations (cell sedimentation, cryopreservation and thawing, mononuclear and CD34+ cell isolation) have on the number, viability and ex vivo expansion potential of PUCB cells. The results presented indicate the necessity of an open discussion on whether procedures used for handling the cells in PUCB banks can be extrapolated or not as such to the clinical use of ex vivo expanded PUCB.

Adult↗
PubMed1999

Correolide and derivatives are novel immunosuppressants blocking the lymphocyte Kv1.3 potassium channels.

The voltage-gated potassium channel, Kv1.3, is specifically expressed on human lymphocytes, where it controls membrane potential and calcium influx. Blockade of Kv1.3 channels by margatoxin was previously shown to prevent T cell activation and attenuate immune responses in vivo. In the present study, a triterpene natural product, correolide, was found to block Kv1.3 channels in human and miniswine T cells by electrophysiological characterization. T cell activation events, such as anti-CD3-induced calcium elevation, IL-2 production, and proliferation were inhibited by correolide in a dose-dependent manner. More potent analogs were evaluated for pharmacokinetic profiles and subsequently tested in a delayed-type hypersensitivity (DTH) response to tuberculin in the miniswine. Two compounds were dosed orally, iv, or im, and both compounds suppressed DTH responses, demonstrating that small molecule blockers of Kv1.3 channels can act as immunosuppressive agents in vivo. These studies establish correolide and its derivatives as novel immunosuppressants.

Animals↗
PubMed1999

Distinct 5' SCL enhancers direct transcription to developing brain, spinal cord, and endothelium: neural expression is mediated by GATA factor binding sites.

The SCL gene encodes a basic helix-loop-helix transcription factor with a pivotal role in the development of endothelium and of all hematopoietic lineages. SCL is also expressed in the central nervous system, although its expression pattern has not been examined in detail and its function in neural development is unknown. In this article we present the first analysis of SCL transcriptional regulation in vivo. We have identified three spatially distinct regulatory modules, each of which was both necessary and sufficient to direct reporter gene expression in vivo to three different regions within the normal SCL expression domain, namely, developing endothelium, midbrain, and hindbrain/spinal cord. In addition we have demonstrated that GATA factor binding sites are essential for neural expression of the SCL constructs. The midbrain element was particularly powerful and axonal lacZ expression revealed the details of axonal projections, thus implicating SCL in the development of occulomotor, pupillary, or retinotectal pathways. The neural expression pattern of the SCL gene was highly conserved in mouse, chicken, and zebrafish embryos and the 5' region of the chicken SCL locus exhibited a striking degree of functional conservation in transgenic mice. These data suggest that SCL performs critical functions in neural development. The regulatory elements identified here provide important tools for analyzing these functions.

Animals↗
PubMed1999

Tissue transglutaminase expression in quail epiphyseal chondrocytes.

Tissue transglutaminase (tTGase) is a GTP-binding Ca(2+)-dependent enzyme which catalyses the post-translational modification via epsilon(gamma-glutamyl)lysine bridges. The physiological role of tTGase is not fully understood. It has been shown that in cartilage the expression of tTGase correlates with terminal differentiation of chondrocytes. Recent evidence suggests that the GTP-binding activity of tTGase may play a role in the control of cell cycle progression thus explaining some of the suggested roles for the enzyme.tTGase activity is present in primary cultures of epiphyseal chondrocytes and increases transiently upon retinoic acid (RA) treatment. Increase in enzyme activity occurs upon RA addition and is accompanied by a parallel increase in protein and mRNA levels. Stimulation of tTGase expression by RA correlates with suppression of cell growth and occurs independently of cell adhesion and cell differentiation.tTGase expression is not observed in MC2, a permanent chondrocyte cell line derived from retrovirus infected chondrocytes. RA treatment fails to activate tTGase expression in MC2 cells and to completely suppress cell proliferation. Our findings lend support to the idea that tTGase might play a role in non-dividing cultured chondrocytes.

Animals↗
PubMed1999

Preterm labor: placental pathology and clinical correlation.

OBJECTIVE: To determine the relevance of ischemia in the incidence of preterm labor. A second objective was to document perinatal outcomes for patients with preterm labor classified according to its clinical, functional, and pathologic characteristics (infectious, ischemic, mixed, or idiopathic). METHODS: Perinatal outcomes were evaluated for 145 consecutive patients with preterm labor, subdivided into etiologic categories according to clinical, functional (Doppler), and morphologic (placental pathology) characteristics. A group of 44 normal pregnancies delivered at term served as controls. RESULTS: Of the preterm labor group, 28.3% were classified as ischemic, compared with 4.5% of the control group (odds ratio and 95% confidence interval = 8.28 [1.8, 51.8]; P < .05). Compared with the control group, the preterm labor patients who delivered preterm had higher rates of ischemia (31.4% compared with 4.5%; P < .05) and infection (16.1% compared with 2.3%; P < .05). Among the preterm labor group, patients classified in the infectious or ischemic subgroups had a higher rate of preterm delivery (95.0% and 90.2% compared with 73.2%; P < .05), admission to the neonatal intensive care unit (75.0% and 61.0% compared with 40.0%; P < .05), and newborn weight under 1500 g (35.0% and 19.5% compared with 3.7%; P < .05) than the idiopathic subgroup. CONCLUSION: Preterm labor resulting from infection or ischemia is associated with a higher perinatal complication rate than idiopathic preterm labor.

Adult↗
PubMed1999

Measuring reversal of hair miniaturization in androgenetic alopecia by follicular counts in horizontal sections of serial scalp biopsies: results of finasteride 1 mg treatment of men and postmenopausal women.

Hair regrowth was evaluated by histologic analysis in men and women treated for androgenetic alopecia, by counting follicles in horizontal sections of scalp biopsies. Serial 4mm punch biopsies were taken at baseline and after 12mo of treatment from the transitional area of hair thinning between normal hair and vertex balding in men, and in an area of frontal/parietal thinning in women. Horizontal sections of reticular and papillary dermis were read by one observer, blinded to patient, treatment, and time. All terminal hair bulbs, terminal anagen and telogen hairs, and vellus and vellus-like miniaturized hairs were counted. Twenty-six men aged 18-41y, comprising 14 on finasteride 1 mg daily and 12 on placebo, and 94 postmenopausal women, aged 41-60y, comprising 44 on finasteride 1 mg daily and 50 on placebo, were evaluated. In the male study, the terminal hairs increased from a mean baseline count of 15.5-20.9 after 12mo of finasteride, versus 17.3-18.3 in the placebo patients. The miniaturized hairs decreased from 26.7 to 23.6 with finasteride versus 21.3-20.3 with placebo. The terminal-to-vellus ratio increased more in the finasteride than in the placebo patients, suggesting some reversal of the miniaturization process with finasteride. In the female study, no significant differences in follicular counts were found between the finasteride and placebo groups after 12mo of treatment. Follicular counts in horizontal sections provide an informative adjunct to noninvasive measures used in hair growth studies. Finasteride appears to be capable of reversing hair miniaturization in androgenetic alopecia in young to middle-aged men, but not in postmenopausal women.

5-alpha Reductase Inhibitors↗
PubMed1999

Pneumonia acquired in the community through drug-resistant Streptococcus pneumoniae.

The aim of the study was to determine the incidence of and risk factors for drug resistance of Streptococcus pneumoniae, and its impact on the outcome among hospitalized patients of pneumococcal pneumonia acquired in the community. Consecutive patients with culture-proven pneumococcal pneumonia were prospectively studied with regard to the incidence of pneumococcal drug resistance, potential risk factors, and in-hospital outcome variables. A total of 101 patients were studied. Drug resistance to penicillin, cephalosporin, or a macrolide drug was found in pneumococci from 52 of the 101 (52%) patients; 49% of these isolates were resistant to penicillin (16% intermediate resistance, 33% high resistance), 31% to cephalosporin (22% intermediate and 9% high resistance), and 27% to a macrolide drug. In immunocompetent patients, age > 65 yr was significantly associated with resistance to cephalosporin (odds ratio [OR]: 5.0; 95% confidence interval [CI]: 1.3 to 18.8, p = 0. 01), and with the presence of > 2 comorbidities with resistance to penicillin (OR: 4.7; 95% CI: 1.2 to 19.1; p < 0.05). In immunosuppressed patients, bacteremia was inversely associated with resistance to penicillin and cephalosporin (OR: 0.04; 95% CI: 0.003 to 0.45; p < 0.005; and OR: 0.46; 95% CI: 0.23 to 0.93; p < 0.05, respectively). Length of hospital stay, severity of pneumonia, and complications were not significantly affected by drug resistance. Mortality was 15% in patients with any drug resistance, as compared with 6% in those without resistance. However, any drug resistance was not significantly associated with death (relative risk [RR]: 2. 5; 95% CI: 0.7 to 8.9; p = 0.14). Moreover, attributable mortality in the presence of discordant antimicrobial treatment was 12%, as compared with 10% (RR: 1.2; 95% CI: 0.3 to 5.3; p = 0.67) in the absence of such treatment. We conclude that the incidence of drug-resistant pneumococci was high. Risk factors for drug resistance included advanced age, comorbidity, and (inversely) bacteremia. Outcome was not significantly affected by drug resistance.

Adult↗
PubMed1999

Severe community-acquired pneumonia. Risk factors and follow-up epidemiology.

The aim of the study was to determine risk factors for severe community-acquired pneumonia (CAP) as well as to compare microbial patterns of severe CAP to a previous study from our respiratory intensive care unit (ICU) originating from 1984 to 1987. Patients admitted to the ICU according to clinical judgment were defined as having severe CAP. For the study of risk factors, a hospital-based case-control design was used, matching each patient with severe CAP to a patient hospitalized with CAP but not requiring ICU admission. Microbial investigation included noninvasive and invasive techniques. Overall, 89 patients with severe CAP were successfully matched to a control patient. The presence of an alcohol ingestion of >/= 80 g/d (odds ratio [OR] 3.9, 95% confidence interval [CI] 1.4 to 10.6, p = 0.008) was found to be an independent risk factor for severe CAP and prior ambulatory antimicrobial treatment (OR 0.37, 95% CI 0.17 to 0.79, p = 0.009) to be protective. Streptococcus pneumoniae (24%) continued to be the most frequent pathogen; however, 48% of strains were drug-resistant. "Atypical" bacterial pathogens were significantly more common (17% versus 6%, p = 0.006) and Legionella spp. less common (2% versus 14%, p = 0.004) than in our previous study, whereas gram-negative enteric bacilli (GNEB) and Pseudomonas aeruginosa continued to represent important pathogens (6% and 5%, respectively). Our findings provide additional evidence for the importance of the initiation of early empiric antimicrobial treatment for a favorable outcome of CAP. Variations of microbial patterns are only in part due to different epidemiological settings. Therefore, initial empiric antimicrobial treatment will also have to take into account local trends of changing microbial patterns.

Adolescent↗