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Biomedical subjects

M Vazquez

Publications and source records attributed to M Vazquez.

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

Special techniques in transthoracic needle biopsy of pulmonary nodules.

We believe that each aspect of the performance of TNB needs to be considered carefully. Meticulous attention to detail allows any nodule in the chest to successfully undergo biopsy. There are techniques of needle tip repositioning that can be quite helpful for obtaining diagnostic material from lung lesions, particularly small nodules. A strong working relationship with pathologists experienced in lung cytology is a vital element of any successful biopsy program. Techniques available to the pathologist allow for quick and decisive determination of the adequacy of the aspirated specimen and help guide the radiologist performing the procedure. Newer cytopathologic techniques help the pathologist make more complex diagnoses from the aspirated material. Finally, techniques used to minimize complications should be considered by the operator before the performance of the biopsy.

Biopsy, Needle↗
PubMed2000

Correction of high astigmatism with astigmatic keratotomy combined with laser in situ keratomileusis.

PURPOSE: To evaluate the efficacy, predictability, and stability of a combined procedure, arcuate keratotomy and laser in situ keratomileusis (LASIK), for the correction of high astigmatism. SETTING: Instituto de Microcirugía Ocular (IMO), Barcelona, Spain. METHODS: Fifteen eyes of 11 patients with naturally occurring astigmatism (NOA) (86. 66%) or surgically induced astigmatism (SIA) (13.34%) between -3.00 and -8.00 diopters (D) who had astigmatic keratotomy were studied. The patients had a secondary procedure, LASIK, to correct the residual refractive error. RESULTS: Mean baseline spherical equivalent refraction was -2.47 D +/- 3.69 (SD) and mean refractive cylinder, -4.59 +/- 1.66 D. Twelve months after LASIK, mean spherical equivalent was -0.09 +/- 1.50 D and the mean refractive cylinder, -1. 21 +/- 1.07 D. The mean cylindrical correction attempted in the NOA group was -4.05 +/- 1.19 D and in the SIA group, -7.00 +/- 1.41 D. Postoperatively, the values were -1.50 +/- 1.17 D and -1.62 +/- 0.17 D, respectively. Twelve months after LASIK, the uncorrected visual acuity (UCVA) was 0.5 +/- 0.1. The UCVA in the NOA group (0.50 +/- 0. 08) was better than in the SIA group (0.32 +/- 0.10). The efficacy index was 0.96 overall. Best corrected visual acuity deteriorated by 1 Snellen line in 1 case (6.6%) but improved by 1 and 2 Snellen lines in 4 cases (26.6%) and 2 cases (13.3%), respectively. All procedures were completed without adverse reactions intraoperatively or postoperatively. CONCLUSION: This combined technique was effective in the treatment of high astigmatism, with excellent results compared with the results of each procedure alone. Because of its high predictability, we strongly recommend the technique in cases with astigmatism higher than 3.0 D, particularly in those with astigmatism higher than 5.0 D.

Adult↗
PubMed2000

Viral strain identification in varicella vaccinees with disseminated rashes.

BACKGROUND: Approximately 15% of recipients of live attenuated varicella vaccine may develop mild breakthrough varicella months to years after immunization. Although some vaccinees will develop zoster, it is less common in recipients of vaccine than in those who have had natural varicella. OBJECTIVE: To determine the varicella-zoster virus (VZV) strain responsible for breakthrough varicella and zoster in recipients of varicella vaccine. METHODS: A PCR assay capable of distinguishing wild-type from vaccine strain VZV was performed on samples from skin lesions from vaccinees with breakthrough varicella and zoster. RESULTS: All of 57 vaccinees with breakthrough varicella, clinically diagnosed on the basis of a generalized maculopapular or vesicular rash, in which there was amplifiable DNA [corrected], had wild-type VZV infection based on analysis of viral DNA. The Oka vaccine strain of VZV was not identified in any of these cases. In contrast, in 32 patients with zosteriform rashes, the vaccine strain was identified in 22 samples, and the wild-type strain was identified in 10 samples. CONCLUSIONS: Wild-type virus was identified in all generalized rashes occurring after the immediate 6-week postvaccination period. When reactivation of vaccine strain occurred, it presented as typical zoster. We find no evidence that reactivation of vaccine virus occurs with the clinical picture of generalized rash.

Case-Control Studies↗
PubMed2000

Impaired expression of the uncoupling protein-3 gene in skeletal muscle during lactation: fibrates and troglitazone reverse lactation-induced downregulation of the uncoupling protein-3 gene.

The expression of uncoupling protein (UCP)-3 mRNA in skeletal muscle is dramatically reduced during lactation in mice. The reduction in UCP-3 mRNA levels lowers the amount of the UCP-3 protein in skeletal muscle mitochondria during lactation. Spontaneous or abrupt weaning reverses the downregulation of the UCP-3 mRNA but not the reduction in UCP-3 protein levels. In lactating and virgin mice, however, fasting increases UCP-3 mRNA levels. Changes in UCP-3 mRNA occur in parallel with modifications in the levels of free fatty acids, which are reduced in lactation and are upregulated due to weaning or fasting. Modifications in the energy nutritional stress of lactating dams achieved by manipulating litter sizes do not influence UCP-3 mRNA levels in skeletal muscle. Conversely, when mice are fed a high-fat diet after parturition, the downregulation of UCP-3 mRNA and UCP-3 protein levels due to lactation is partially reversed, as is the reduction in serum free fatty acid levels. Treatment of lactating mice with a single injection of bezafibrate, an activator of the peroxisome proliferator-activated receptor (PPAR), raises UCP-3 mRNA in skeletal muscle to levels similar to those in virgin mice. 4-chloro-6-[(2,3-xylidine)-pirimidinylthio] acetic acid (WY-14,643), a specific ligand of the PPAR-alpha subtype, causes the most dramatic increase in UCP-3 mRNA, whereas troglitazone, a specific activator of PPAR-gamma, also significantly increases UCP-3 mRNA abundance in skeletal muscle of lactating mice. However, in virgin mice, bezafibrate and WY-14,643 do not significantly affect UCP-3 mRNA expression, whereas troglitazone is at least as effective as it is in lactating dams. It is proposed that the UCP-3 gene is regulated in skeletal muscle during lactation in response to changes in circulating free fatty acids by mechanisms involving activation of PPARs. The impaired expression of the UCP-3 gene is consistent with the involvement of UCP-3 gene regulation in the reduction of the use of fatty acids as fuel by the skeletal muscle and in impaired adaptative thermogenesis, both of which are major metabolic adaptations that occur during lactation.

Animals↗
PubMed1999

Cyclosporin A does not increase the oxidative susceptibility of low density lipoprotein in vitro.

Accelerated atherosclerosis is the leading cause of morbidity in renal transplant recipients. The pathogenic mechanisms responsible for the progression of atherosclerosis in renal transplant recipients have not been elucidated. Cyclosporin A (CsA) is an immunosuppressive agent used post-transplant and may contribute to increased oxidative susceptibility of low density lipoprotein (LDL). There is a paucity of data testing the effect of CsA on LDL oxidation. Hence, the aim of this study was to test the effect of in vitro enrichment of LDL with CsA on LDL oxidation. LDL oxidation in presence of different concentrations of CsA was tested using metal-dependent (copper), metal-independent (AAPH) and cell-mediated (macrophages) oxidation systems. In all 3 systems, CsA had no significant effect on LDL oxidation. Also, pre-incubation of LDL with CsA did not affect LDL oxidation and LDL alpha tocopherol levels. Thus, the results of our studies with CsA indicate that it is not a direct pro-oxidant.

Amidines↗
PubMed1999

[Arteriovenous malformations in the jaws. The place of intravascular therapy. Apropos of 14 cases].

PURPOSE: To analyze arteriovenous malformations (AVMs) of maxillo-mandibular arcades seen in our department since 1977, and to determine adequate treatment. MATERIAL AND METHODS: Fourteen AVMs were reviewed to determine their revelation, their semiology, the treatment applied and the results that could be obtained. All these lesions were true AV shunts involving bone with or without soft tissue extension. RESULTS: Eight patients belonged to the pediatric population. Six lesions were maxillary and 8 mandibular. All lesions were revealed during or after puberty by local swelling, pain, mass effect or bruit. Hemorrhage was the most frequent (71%) symptom. Teeth instability was detected in all these patients and was origin of the bleeding. The lesions were suspected clinically and confirmed radiologically. Angiography analyzed properly the architecture of the lesion (4 arteriovenous fistulas). Embolization was the clinical treatment in all patients: particles helped to stabilize the acute situations but failed to offer stable results, necessitating complementary embolizations and/or surgery (hemimandibulectomy in 2 patients). The use of acrylic glue (Histoacryl), injected percutaneously (5 patients), or transarterially in the AVM (4 patients)) provided cure in 6 of these lesions (43%) and long term stabilization for all the other AVMs. Teeth extraction could be performed thereafter in good conditions. Antibiotics and anti-inflammatory treatment helped to stabilize the evolutive risk of these lesions. CONCLUSION: Embolization is the therapy of choice in these lesions. Appropriate use of glue offers a high rate of cure and/or clinical stabilizations and avoids unneeded surgery.

Adolescent↗
PubMed1998

Production of carotenoids by phaffia rhodozyma growing on media made from hemicellulosic hydrolysates of eucalyptus globulus wood

Phaffia rhodozyma NRRL Y-17268 cells were proliferated in xylose-containing media made from Eucalyptus wood. Wood samples were subjected to acid hydrolysis under mild operational conditions, and hydrolysates were neutralized with lime. Neutralized hydrolysates were treated with charcoal for removing inhibitors and then supplemented with nutrients to obtain culture media useful for proliferation of the red yeast P. rhodozyma. A set of experiments carried out in orbital shakers proved that hydrolysates containing 16.6 g xylose/L supplemented only with 3 g peptone/L performed well as fermentation media. At the end of experiments, xylose was depleted and 10.5 g cells/L were obtained. Biomass was highly pigmented and volumetric carotenoid concentrations up to 5.8 mg carotenoids/L (with 4.6 mg astaxanthin/L) were reached. Further experiments in batch fermentors using concentrated hydrolysates (initial xylose concentrations within 16.6 and 40.8 g/L) led to good biomass concentrations (up to 23.2 g cells/L) with increased pigment concentration (up to 12.9 mg total carotenoids/L, with 10.4 mg astaxanthin/L) and high volumetric rates of carotenoid production (up to 0.079 mg/L.h). Copyright 1998 John Wiley & Sons, Inc.

Journal Article↗
PubMed1997

Effects of X-irradiation on nerve growth factor in the developing mouse brain.

The involvement of neurotrophins after radiation injury during brain development were studied in pregnant mice (C 57/B1) exposed on gestation day 15 to X-ray doses of 0.02-2 Gy. Nerve growth factor protein (NGF) and different cholinergic markers were investigated on postnatal day 1 (P1) and day 21 (P21); in situ hybridization with brain-derived neurotrophic factor (BDNF) and trkC (receptor serving to bind neurotrophin-3) probes was investigated on P21 in cortex, hippocampus, septum and cerebellum. The level of NGF protein was increased in irradiated forebrain on P1 in a dose-related manner. However, on P21 the NGF protein dropped down below the control levels in irradiated hippocampus and cerebellum. The response of acetylcholine esterase (AChE) activity in cerebellum at P21 was correlated with the changes in the amount of NGF. The intensity of cell labelling with trkC probe decreased after irradiation in the region of the hippocampus at P21, especially in dentate gyrus. The expression of BDNF mRNA was increased at P21 by low doses of irradiation (0.02-1 Gy) but was decreased by a high dose (2 Gy) in the same area. Thus, the radiation induced an alteration of neurotrophins, and the changes varied depending on the dose or time after irradiation. Such alterations in the pattern of growth factor production may modulate the response of cells to radiation. Furthermore, NGF protein levels and the expression of BDNF and trkC mRNA were affected by radiation doses as low as 0.02 Gy, indicating that during development the neurotrophins and their receptors are very sensitive to radiation.

Acetylcholinesterase↗
PubMed1996

The PPARalpha-leukotriene B4 pathway to inflammation control.

Inflammation is a local immune response to 'foreign' molecules, infection and injury. Leukotriene B4, a potent chemotactic agent that initiates, coordinates, sustains and amplifies the inflammatory response, is shown to be an activating ligand for the transcription factor PPARalpha. Because PPARalpha regulates the oxidative degradation of fatty acids and their derivatives, like this lipid mediator, a feedback mechanism is proposed that controls the duration of an inflammatory response and the clearance of leukotriene B4 in the liver. Thus PPARalpha offers a new route to the development of anti- or pro-inflammatory reagents.

Adaptation, Physiological↗
PubMed1996

Transient outward K+ channels in vesicles derived from frog skeletal muscle plasma membranes.

Whole-cell voltage-clamp experiments were performed in vesicles derived from frog skeletal muscle plasma membranes. Capacitance measurements showed that these vesicles lack invaginations. In solutions containing K+, transient outward currents with reversal potentials close to EK were recorded with a maximum potassium conductance of 0.3 mS/cm2. These currents inactivated in a voltage-dependent manner with a time constant of decay that reached a limiting value of 26 ms at large depolarizations. The steady-state inactivation reached half-maximum values at -66 mV. Transient currents were completely blocked with 5 mM 4-aminopyridine. Single-channel recordings made in inside-out excised patches from the vesicles had ensemble averages with characteristics similar to those of the macroscopic currents, although with significantly faster inactivation time constants. The single-channel chord conductance was 21 pS when the pipette and bath solutions contained 2.5 mM and 120 mM KCl, respectively. It is concluded that these vesicles contain potassium channels that are very similar to A channels found in neurons and other cells.

Animals↗
PubMed1996

Variation in plasma lipid and lipoprotein concentrations in community-acquired pneumonia a six-month prospective study.

The nature of changes in the lipid profile caused by an acute infection is controversial. The aims of the present study were to study the changes in plasma lipids and lipoproteins in community-acquired pneumonia, to determine whether these changes differ according to the aetiologica/agents, and finally to observe the behaviour of these lipoproteins six months later. Sixty patients, aged between 18 and 87 years, admitted during the period September 1992 and April 1993 with suspected community-acquired pneumonia, were included in the study. Fifty-three of the patients completed the 15-day follow-up investigation, and 37 remained available for study for up to 6 months. On admission and at 15 and 180 days, analyses were carried out for total cholesterol, HDL cholesterol, apolipoproteins A1 and B, triacylglycerols and transaminases. Student's t test for parametric variables was used for statistical analysis, and the Mann-Whitney test for non-parametric variables. The concentrations of total cholesterol (4.2 +/- 1.0 vs 5.5 +/- 1.3 mmol/1), HDL cholesterol (0.9 +/- 0.4 vs 1.2 +/- 0.3 mmol/l), apolipoprotein A1 (0.80 +/- 0.25 vs 1.15 +/- 0.28 g/l) and apolipoprotein B (0.77 +/- 0.28 vs 0.95 +/- 0.28 g/l) showed significantly lower values during the acute infectious process. These analyte concentrations became stable after 15 days with the exception of HDL cholesterol which continued to increase until 6 months (1.2 +/- 0.3 vs 1.3 +/- 0.3 mmol/l, p < 0.01). Patients with non-viral atypical pneumonia showed, on admission, higher triacylglycerol values (1.8 +/- 0.8 vs 1.3 +/- 0.9 mmol/l, p < 0.01) and lower HDL cholesterol values (0.6 +/- 0.3 vs 1.0 +/- 0.4 mmol/l, p < 0.03). Values of aspartate aminotransferase (112 +/- 117 vs 23 +/- 11 U/l, p < 0.001), alanine aminotransferase (127 +/- 141 vs 24 +/- 16 U/l, p < 0.02) and gamma-glutamyl transferase (113 +/- 158 vs 33 +/- 25 U/l, p < 0.03) were higher in the subgroup of non-viral atypical pneumonia. In conclusion, patients with community-acquired pneumonia present a significant decline in total cholesterol, HDL cholesterol and apolipoprotein A1 and B concentrations. Lower concentrations of HDL cholesterol are maintained up 15 days. Patients with non-viral atypical pneumonia present on admission significantly higher triacylglycerol and lower HDL cholesterol values. Those with non-viral atypical pneumonia also present higher transaminase values.

Adolescent↗