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Biomedical subjects

V Martín

Publications and source records attributed to V Martín.

At least 19 recordsLinked to original sources
PubMed2003

[First steps in neuronavigation].

INTRODUCTION: We try to evaluate the introduction of a neuronavigation system widely used in a neurosurgical department. MATERIAL AND METHODS: We analyze the surgical procedures performed since the introduction of a neuronavigator in our hospital, the advantages and the problems related with its use. RESULTS: From 21/12/00 to 31/12/01, 64 cranial and 5 spinal procedures were performed in our centre with the aid of the BrainLAB neuronavigation system. They were 19.37% of the elective surgeries: 45.7% of cranial and 2.8% of spinal procedures. The accuracy of registration was 1.6 mm; the number of trials for registration was 2.8 on average, although in 3 cases it was not possible; there were disarrangements during 9 surgical procedures (two of them after the lesions were reached). Magnetic resonance imaging (MRI) was used in 54 instances, computerized tomography (CT) in 5, fluoroscopy (Rx) in 1, CT plus MRI in 8, CT plus Rx in 1. Since Z-Touch localization system and software was available, it was used exclusively, disregarding the use of external fiducials. DISCUSSION AND CONCLUSIONS: In our experience, neuronavigation needs extra time, but it helps in the election of the best position for the surgical approach, reduces the time required for scalp incision and craniotomy planning, and is useful for the opening of the dura and the corticectomy. As the operation proceeds, we found it less truhstworthy and necessary. The Z-touch system frees the imaging from the surgery. Its use in spinal operation is scarce and with limited results in our practice. We found the neuronavigation useful, and we employ it on a regular basis in every cranial procedure whenever it is possible.

Humans↗
PubMed2003

[Ischemic anterior syndrome and intraocular calcification].

OBJECTIVE/METHODS: We report the case of a sixty-year-old female that following retinal detachment surgery in her left eye, presented with a clinical picture that initially was misdiagnosed as endophthalmitis. RESULTS/CONCLUSIONS: The patient suffered an anterior ischemic syndrome secondary to the retinal surgery, and accidentally, the presence of an intraocular calcification was discovered. We study the influence of the osteoblastic neoformation in the ischemic process.

Calcinosis↗
PubMed2002

[Spontaneous resolution of an acute subdural hematoma].

Acute postraumatic subdural hematoma is known to have bad prognosis. Traditionally, its treatment consisted in urgent surgical evacuation. Rapid spontaneous resolution of the hematoma has been infrequently observed. We report a case of a patient with an acute traumatic subdural hematoma which disappeared without surgery. CT-scan showed a left-sided subdural hematoma with marked mass effect. A low density layer, which implied involvement of CSF in the subdural space, was observed between the hematoma and the inner wall of the skull. We think that the spontaneous resolution of the hematoma was due to the dilution and washing-out by the CSF through an arachnoid tear. Another suggested mechanism in the literature is blood redistribution in the subdural space. Selected patients with an acute subdural hematoma can be managed with conservative treatment.

Aged↗
PubMed2002

[Surgical treatment of patients with spinal infection].

INTRODUCTION: The surgical treatment of spinal infection, relegated because of the development of more effective antibiotherapy and the fear of associated morbidity, is springing up again with the increase of new patients with weakening pathology. MATERIAL AND METHODS: The clinical records of 27 patients submitted to surgery because of spinal infection between January 1990 and December 1999 at our service have been retrospectively studied. They were assessed with the Frankel and Karnofsky clinical scales, and the radiological angulation of the spine. RESULTS: Male (n = 17) and dorsal lesions (n = 14) predominate. Most of patients presented with pain, and 13 had neurological compromise. 29 operations were performed on the 27 patients. One of them was previously operated upon before the period considered, that procedure has been excluded. The total surgeries performed were 5 simple and 4 instrumented laminectomies, 6 simple corpectomies, 10 corpectomies with anterior instrumentation and 4 with posterior instrumentation. One patient died, there was not definitive morbidity and any patient deteriorated on clinical scales although radiology was not always improved. DISCUSSION AND CONCLUSIONS: The aggressive treatment of spinal infection is indicated when conservative means are insufficient. Surgery permits a better recovery of the neurological deficit, and prevents spinal deformity and pain produced by the disease.

Adolescent↗
PubMed2002

Effectiveness of tuberculosis control programmes in prisons, Barcelona 1987-2000.

SETTING: Different bodies have emphasised the need for prisons to implement and evaluate their own tuberculosis prevention and control programmes (TPCP), with the aims of evaluating TPCP in Barcelona prisons and obtaining conclusions that would allow any necessary modifications to be introduced to improve their effectiveness. METHODS: An assessment was carried out for the period 1987-2000, using the exhaustive retrospective method. The quantitative indicators used were defined in the same way as those employed by the Barcelona TPCP, which were taken as the gold standard. The assessment studied trends in the indicators and evaluated the impact by comparing the results with the gold standard. RESULTS: Statistically significant trends (P < 0.0001) were found for incidence rates, infection prevalence, treatment adherence rates among smear-positive cases and percentage of cases on directly observed treatment (DOT). When impact was assessed, only the decline in the average annual incidence rate (25.2%) and desired rates of adherence among smear-positives (> or = 95% since 1993) achieved the proposed objectives. CONCLUSIONS: The observed decline in incidence shows that when programmes are based on reducing diagnostic delay, controlling adherence using DOT and tracing contacts, tuberculosis control among the prisons is effective.

Antitubercular Agents↗
PubMed2001

The sterol-sensing domain of Patched protein seems to control Smoothened activity through Patched vesicular trafficking.

The Hedgehog (Hh) family of signaling molecules function as organizers in many morphogenetic processes. Hh signaling requires cholesterol in both signal-generating and -receiving cells, and it requires the tumor suppressor Patched (Ptc) in receiving cells in which it plays a negative role. Ptc both blocks the Hh pathway and limits the spread of Hh. Sequence analysis suggests that it has 12 transmembrane segments, 5 of which are homologous to a conserved region that has been identified in several proteins involved in cholesterol homeostasis and has been designated the sterol-sensing domain (SSD). In the present study, we show that a Ptc mutant with a single amino acid substitution in the SSD induces target gene activation in a ligand-independent manner. This mutant Ptc(SSD) protein shows dominant-negative activity in blocking Hh signaling by preventing the downregulation of Smoothened (Smo), a positive effector of the Hh pathway. Despite its dominant-negative activity, the mutant Ptc protein functioned like the wild-type protein in sequestering and internalizing Hh. In addition, we show that Ptc(SSD) preferentially accumulates in endosomes of the endocytic compartment. All these results suggest a role of the SSD of Ptc in mediating the vesicular trafficking of Ptc to regulate Smo activity.

Alleles↗
PubMed2001

[Intracranial epidural abscess in a newborn secondary to skin catheter].

Intracranial epidural abscesses are uncommon lesions, being more frequents in older children and adults. They commonly arise as a result of direct extension of a preexisting infection and rarely present with focal deficit. We present a case of a 11-days old preterm infant who developed an intracranial epidural abscess as a result of an infected scalp vein catheter. The diagnosis was made on the basis of the cranial ultrasound and CT scan images. An identified strain of Enterococcus faecium was cultured from all the samples. The patient underwent a right frontal craniotomy with drainage of the abscess and a 2-week total course of intravenous antibiotics was administrated. CT scan imaging 3 week after the procedure demonstrated no evidence of residual lesion. When present, a scalp vein catheter, in absence of others predisponing factors, must be considered as an etiologic agent for an intracranial epidural abscess in this age-group.

Catheterization↗
PubMed2001

Glutamate induces oxidative stress not mediated by glutamate receptors or cystine transporters: protective effect of melatonin and other antioxidants.

Glutamate is responsible for most of the excitatory synaptic activity and oxidative stress induction in the mammalian brain. This amino acid is increased in the substantia nigra in parkinsonism due to the lack of dopamine restraint to the subthalamic nucleus. Parkinson's disease also shows an increase of iron levels in the substantia nigra and a decrease of glutathione, the antioxidant responsible for the ascorbate radical recycling. Considered together, these facts could make the antioxidant ascorbate behave as a pro-oxidant in parkinsonism. Since both glutamate and ascorbate are present in the synaptosomes and neurons of substantia nigra, we tested 1) if glutamate is able to induce oxidative stress independently of its excitatory activity, and 2) if ascorbate may have synergistic effects with glutamate when these two molecules co-exist. Brains were homogenized in order to disrupt membranes and render membrane receptors and intracellular signaling pathways non-functional. In these homogenates glutamate induced lipid peroxidation, indicating that this amino acid also may cause oxidative stress not mediated by its binding to glutamate receptors or cystine transporters. Ascorbate also induced lipid peroxidation thus behaving as a pro-oxidant. Both substances together produced an additive effect but they did not synergize. Given that melatonin is a potent physiological antioxidant with protective effects in models of neurotoxicity, we tested the role of this secretory product on the pro-oxidant effect of both compounds given separately or in combination. We also checked the protective ability of several other antioxidants. Pharmacological doses of melatonin (millimolar), estrogens, pinoline and trolox (micromolar) prevented the oxidant effect of glutamate, ascorbate, and the combination of both substances. Potential therapeutic application of these results is discussed.

Acetylcysteine↗
PubMed2001

Steady state responses to multiple amplitude-modulated tones: an optimized method to test frequency-specific thresholds in hearing-impaired children and normal-hearing subjects.

OBJECTIVE: To evaluate, using statistical methods, the usefulness of the binaural multiple frequency auditory steady state responses (MF SSRs) for objective, frequency-specific audiometry in a large sample of hearing-impaired children and normal-hearing subjects. DESIGN: The MF SSRs were recorded in a sample of 43 hearing-impaired children (86 ears) and 40 normal-hearing young adults (80 ears). Simultaneous carrier tones (0.5, 1, 2, and 4 kHz) modulated in amplitude at different rates (77 to 105 Hz) were presented binaurally (TDH 49 earphones) at variable intensities (110 to 20 dB SPL). For each subject the response thresholds (RTHs) at 0.5, 1, 2, and 4 kHz, were determined automatically (F test) and compared with the corresponding behavioral thresholds (BTHs). RESULTS: In the normal-hearing subjects, RTHs were detectable, on average, between 11 and 15 dB above the BTH. These differences were significantly smaller in the hearing-impaired (5 to 13 dB). Also a close correspondence was found between the subjective and objective audiogram curves in both groups. The within subject Spearman correlation coefficients calculated between the two curves, were in most cases above the significance cut off point (p < 0.05). Also in 1-way repeated measures analysis of variance, the overall error in the estimation of the audiogram (vector across frequency of absolute distances between the curves) did not differ significantly from zero. CONCLUSIONS: The binaural MF SSR was proven to be a valid technique for the estimation of an objective audiogram, in a large sample of hearing-impaired children and normal-hearing subjects. With this method, frequency-specific thresholds at 0.5, 1, 2, and 4 kHz could be determined in all subjects (and both ears) with no appreciable loss in accuracy and a considerable reduction in testing time (average recording time = 21 minutes) when compared with other frequency-specific techniques.

Acoustic Impedance Tests↗
PubMed2000

Cancer gene therapy by thyroid hormone-mediated expression of toxin genes.

Many of the strategies developed in the last few years to treat cancer by gene therapy are based on putative killer-suicide genes whose products convert a prodrug into a toxic compound. When the therapy is applied to humans, a vector carrying the killer gene is first inoculated into the tumor of the patient, who 1 week later receives the corresponding prodrug that will selectively kill the cells able to process it to its toxic derivative. A strategy that obviates the need for a prodrug to destroy the cancer cells would be preferable because the patient would only need one treatment instead of two consecutive ones. In the following study, we describe the construction of retroviral vectors in which a reporter or a toxin gene (either the Pseudomonas exotoxin or the Ricinus communis toxin, ricin) is placed under the control of the thyroid hormone (T3) regulatable promoter of the rat myelin basic protein (MBPp). We demonstrate that the expression of these genes under the control of MBPp is regulated by T3 in vitro and in vivo. In vitro, the MBPp is switched off when T3 is removed from the serum of the culture medium, allowing the production of retroviruses carrying the toxic gene. In vivo, the toxin gene bearing retroviruses is capable of eradicating experimentally induced brain tumors in Wistar rats. The gene therapy strategy described here does not require the use of a prodrug to destroy the neoplastic cells.

Animals↗
PubMed2000

bgs2+, a sporulation-specific glucan synthase homologue is required for proper ascospore wall maturation in fission yeast.

The formation of the ascospore cell wall of Schizosaccharomyces pombe requires the co-ordinated activity of enzymes involved in the biosynthesis of its components, such as glucans. We have cloned the bgs2+ gene. bgs2+ belongs to the glucan synthase family of S. pombe and is homologous to the Saccharomyces cerevisiae FKS1 and FKS2 genes. Deletion or overexpression of this gene does not lead to any apparent defect during vegetative growth, but homozygous bgs2Delta diploids do show a sporulation defect. Although meiosis takes place normally, ascospores are unable to mature, and their wall differs from that of wild-type ascospores. Moreover, bgs2Delta zygotes were not able to release ascospores spontaneously, and the ascospores were unable to germinate. We show that expression of bgs2+ is restricted to sporulation and that a bgs2-green fluorescent protein (GFP) fusion protein localizes to the ascospore envelope. The glucan synthase activity in sporulating diploids bearing a bgs2 deletion was diminished in comparison with that of the wild-type diploids, a fact that underscores the importance of the bgs2+ gene and glucan synthesis for the proper formation and maturation of the ascospore wall.

Amino Acid Sequence↗
PubMed2000

Mycobacterium tuberculosis and human immunodeficiency virus co-infection in intravenous drug users on admission to prison.

BACKGROUND: Intravenous drug users (IDUs) and prisoners are groups of great interest in human immunodeficiency virus (HIV) infection and tuberculosis (TB) epidemiology. AIM: To determine predictors and temporal trends of the co-infection of Mycobacterium tuberculosis and HIV in IDUs on admission to prison. PATIENTS AND METHODS: Between 1 January 1991 and 31 December 1997, 796 IDUs or former IDUs were studied. Socio-demographic and penitentiary variables were evaluated. HIV-positive patients with > or =5 mm induration on tuberculin test were deemed co-infected. Analysis of factors associated with co-infection was based on a logistic regression model. RESULTS: Of the incoming prisoners, 44.0% were infected by M. tuberculosis, 43.8% by HIV and 20.1% were co-infected. Co-infection predictors were: 1) total prison time served previously (none, OR 1; <2 years, OR 2.44, 95% CI 1.28-4.64; > or =2 years, OR 4.94, 95% CI 2.56-9.55); 2) age (16-25 years, OR 1; 25-29 years, OR 3.14, 95% CI 1.71-5.75; >29 years, OR 3.67, 95% CI 1.96-6.86); 3) tattoos (OR 1.56, 95% CI 0.98-2.49), 4) syringe sharing (OR 2.43, 95% CI 1.57-3.77) and 5) ex-IDU status (OR 1.87, 95% CI 1.23-2.82). No statistically significant variation in the annual co-infection tendency was observed (OR 1.10, 95% CI 0.98-1.22). CONCLUSIONS: The high prevalence of co-infection that was detected was associated with risk factors that could be amended by public health intervention.

AIDS-Related Opportunistic Infections↗
PubMed1999

Use of the 2A sequence from foot-and-mouth disease virus in the generation of retroviral vectors for gene therapy.

We describe the construction of retroviral plasmid vectors in which two genes are linked by a minimum of 96 nucleotides encoding the 2A sequence from the picornavirus foot-and-mouth disease virus (FMDV). Transcription and translation gives rise to a bicistronic mRNA and two independent protein products. The system offers advantages to other alternative ways to create polycistronic mRNAs and can be used in gene therapy delivery vectors.

3T3 Cells↗
PubMed1998

[Evolution of the prevalence of Mycobacterium tuberculosis infection in a penitentiary population on admission to prison from 1991 to 1996].

BACKGROUND: In Spanish prisons tuberculosis is a serious problem of public health. The analysis of temporal trends of tuberculous infection can show the effectiveness of interventions developed. PATIENTS, MATERIAL AND METHODS: All admissions in a prison between July 1991 and June 1996, without antecedents of chemotherapy or chemoprophylaxis, were included. We gathered sociodemographic variables as well as prison-related variables and HIV-risk factors. Tuberculin skin test was performed with 2 U of PPD RT-23 following the Spanish Consensus to Criterion of Tuberculous Infection. Statistic analysis was based on multivariate analysis (logistic regression). RESULTS: 37% of 1,459 prisoners analyzed were infected with M. tuberculosis. The tuberculous infection was more frequent among older prisoners (p < 0.001) and those with more time spent in prison (p < 0.001). Those with BCG-vaccination showed lesser levels of tuberculin reaction (p = 0.001). Temporal trends of tuberculous infection didn't show variations, but in intravenous drug users IVDU (p = 0.012) and those with time spent in prison (p = 0.08) it was increased. CONCLUSIONS: We detected a high prevalence of tuberculous infection and the time spent in prison was one of the risk factors. The infection was probably underestimate among those with BCG-vaccination because of the criterion used. The tuberculous infection was increased among IVDU and those with antecedent of time spent in prison.

Adolescent↗
PubMed1998

Significance of angiographic coronary dissection after cutting balloon angioplasty.

We studied 2 groups of patients with (n = 14) and without (n = 42) minor coronary dissections following cutting balloon angioplasty. Patients with a minor dissection had a longer length of lesion, higher percentage of stenosis, and greater acute gain after angioplasty; at 6-month follow-up both groups had a similar net gain and restenosis rate, suggesting that minor dissection after cutting balloon angioplasty has no influence on restenosis.

Adult↗
PubMed1998

[Initial results with the Multi-Link coronary stent].

INTRODUCTION AND OBJECTIVES: The Multi-Link intracoronary stent is a balloon-expandable stainless steel stent with an interconnected ring structure designed to provide a high degree of compressive resistance while preserving longitudinal flexibility. We present the results of our initial experience with the implantation of this stent. PATIENTS AND METHODS: From May 1996 to April 1997, 124 Multi-link stents were implanted in 97 patients. Mean age 62.2 +/- 11 years. All patients included had a coronary artery diameter > 2.7 mm. Clinical presentation includes stable angina in 20, unstable angina in 72, and myocardial infarction in 5 patients. According to the ACC/AHA classification 6 lesions were type A, 72 type B and 19 type C. The implantation of the stent was for "de novo" lesions in 85 patients and for restenosis in 12. Patients were treated after the procedure with a combination of aspirin and ticlopidine, except six of them who received aspirin and acenocumarol. 16 patients were treated additionally with Abciximab. The degree of stenosis was determined by quantitative angiography. RESULTS: The delivery of the stent was successful in all patients. The degree of stenosis before the procedure was 79.6 +/- 13.1%, and after the stent deployment was 17.7 +/- 11.4%. Three patients presented a non-Q-wave myocardial infarction, two patients had a subacute stent thrombosis, one of them died due to heart failure. During a follow-up of 4.7 +/- 2.6 months five patients were readmitted with recurrent angina (4 due to restenosis and one for vessel occlusion) and one patient with heart failure after myocardial infarction died suddenly three weeks after the dilatation. CONCLUSIONS: The Multi-Link stent was implanted successfully in all patients with a low incidence of complications, showing at the follow-up a reduced rate of clinical restenosis.

Coronary Disease↗
PubMed1998

Predictive factors of HIV-infection in injecting drug users upon incarceration.

OBJECTIVE: To identify predictors of HIV-infection in injecting drug users upon incarceration. PATIENTS AND METHODS: We studied 639 IDU or ex-IDU prisoners admitted to a provincial prison of Northwestern Spain between 1 January 1991 and 31 December 1995. Each was interviewed by health personnel and tested for HIV-infection (ELISA followed by immunoblot confirmation in positive cases). Statistical analysis was based on logistic regression. RESULTS: The prevalence of HIV-infection was 46.9% (95% CI: 43.1%-50.8%). No decreasing tendency in annual prevalence of HIV-infection was observed (p = 0.88); however, for those incarcerated for the first time prevalence fell from 38% in 1991 to 19% in 1995 (p = 0.20). Gypsies (OR: 0.43; 95% CI: 0.23-0.80) and prisoners who were older upon first incarceration (OR: 0.94; 95% CI: 0.90-0.99) were associated with lesser risk of HIV-infection. Women (OR: 2.17; 95% CI: 1.29-3.65), older prisoners (OR: 1.06; 95% CI: 1.02-1.11), those with multiple incarceration histories (OR: 1.06; 95% CI: 1.01-1.11) and long-term prisoners (OR: 1.01; 95% CI: 1.00-1.02) were associated with higher risk. CONCLUSIONS: The high prevalence of HIV-infection, especially in women, younger prisoners, repeat offenders and long-term prisoners, suggests that prevention measures directed toward the most marginal IDU have not been very effective. Harm-reduction programs must be made to reach the IDU population, both in and outside prison walls.

AIDS Serodiagnosis↗