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Biomedical subjects

V Martín

Publications and source records attributed to V Martín.

At least 37 records · Page 2Linked to original sources

[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↗

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↗

Successful use of a plant gene in the treatment of cancer in vivo.

A new strategy for cancer gene therapy has been developed using a plant gene which encodes the enzyme, linamarase, that hydrolyzes the cyanogenic glucoside substrate, linamarin, into glucose, acetone and cyanide. Retroviral vectors that carry linamarase as a potential killer-suicide gene cause a marked sensitization to the innocuous substrate, linamarin, followed by cell death. We show that the system can eradicate very large intracerebral gliomas in vivo helped by a cyanide bystander effect. Animals showing a total regression of the tumor by magnetic resonance imaging (MRI), do not show other appreciable toxic effects.

Animals↗

Gene therapy in brain tumours: implications of the size of glioblastoma on its curability.

The authors have used the thymidine kinase/ganciclovir system to block glioblastoma multiforme neoplastic cells in vivo, both in experimental animals and in two patients in which the more conventional therapies had been unsuccessful. In the Wistar rat it was found that the curability potential of the system is correlated with tumoral volume. Tumours smaller than 20 mm3 can be cured with defective retrovirus that do not carry the Herpes simplex thymidine kinase (Hsvtk) gene. While tumours smaller than 150 mm3 can regress totally by the kinase/ganciclovir system, those above that size cannot be cured by this treatment. In humans the situation seems very similar in that the authors have been unable either to reduce the tumour size of recurrent patients with tumour volumes larger than 100 cm2 applying the standard thymidine kinase/ganciclovir gene therapy or to prolong their survival time more than 8 months [7]. When a combination of size reduction by neurosurgery and gene therapy was used the survival time increased considerably. Two patients have been treated by partial surgery and repeated treatment with thymidine kinase/ganciclovir through an Ommaya reservoir connected to a catheter leading into the tumour cavity. The magnetic resonance imaging (MRI) of these patients show only a residual tumoral growth along side the tumoral bed. The procedure may be partially controlling the proliferation of cancerous cells, because, these two patients having recurrent glioblastoma, are alive 11 and 17 months after the beginning of the treatment.

Animals↗

Human malignant brain tumor response to herpes simplex thymidine kinase (HSVtk)/ganciclovir gene therapy.

Growing cells from human brain tumors have been treated in vitro and in vivo with murine therapeutic retroviral producer cells. The therapeutic retrovirus carried the potential suicide gene thymidine kinase (tk) from the herpes simplex virus (HSV). After a few days, in which a large proportion of the tumoral cells had the opportunity to acquire a copy of the retrovirus, treatment with ganciclovir was initiated and considered responsible for considerable cell death both in vitro and in vivo. The in vivo experiments were performed in five adult patients who had failed standard therapy and were expected to survive only a few weeks.

3T3 Cells↗

Differential characteristics of AIDS patients with a history of imprisonment.

BACKGROUND: AIDS is among the leading causes of death in prisons, but there is little information about AIDS patients with a history of imprisonment. METHODS: AIDS patients diagnosed in Barcelona between 1988 and 1993 were studied. Those with prison histories were compared to those without, with respect to epidemiological variables, including survival analysis. RESULTS: 28.5% of 2336 AIDS patients, 49.4% of intravenous drug users (IVDU) and only 2.6% of homosexuals who were not IVDU had a prison history. Those with prison histories, compared to those without, were younger (median age of 30.6 versus 36.4, P < 0.0001), more often IVDU than homosexuals (87.8% versus 35.8%, OR = 36.9, 95% CI: 22.6-60.8, P < 0.0001), and diagnosed with AIDS because of extrapulmonary tuberculosis (32.0% versus 14.7%, P < 0.001). Among IVDU, those with prison histories were more frequently males (OR: 2.2; 95% CI: 1.6-2.9), lived in the poorest district of Barcelona more frequently than in the richest district (OR: 6.6; 95% CI: 3.4-12.9) and presented with extra-pulmonary tuberculosis more frequently than Pneumocystis carinii pneumonia (OR: 1.7; 95% CI: 1.2-2.4). Longer survival in the prison group did not persist when adjusted for age and AIDS-defining disease. Those with prison histories who presented with AIDS with only extrapulmonary tuberculosis had better probability of survival than those who presented only with P. carinii pneumonia (P < 0.001). CONCLUSIONS: AIDS patients in Barcelona with prison histories tended to be younger, more likely to be IVDU, and to present with extrapulmonary tuberculosis as an AIDS-defining illness than other patient groups. Better survival appears to be related to age and AIDS-defining illnesses in the prison group. The fact that half the IVDU AIDS cases had prison histories has important implications for the care and prevention of HIV, tuberculosis, and drug abuse in comparable prison settings.

Acquired Immunodeficiency Syndrome↗

Long-term rat survival after malignant brain tumor regression by retroviral gene therapy.

Total regression of malignant brain tumors was observed in Wistar rats after retrovirus-mediated gene therapy. Tumors were induced by inoculation of C6 rat glioblastoma cells to a specific location in the rat brain and the tumors that developed were visualized by magnetic resonance imaging (MR). Retroviral vectors were constructed from a defective murine retrovirus to which the thymidine kinase (tk 1) gene from herpes simplex was added (HSV1tk). The vectors produced therapeutic viruses upon their introduction into retrovirus packaging cells. Delivery of the producer cells to the tumor mass and subsequent antiherpetic treatment eradicated the tumors completely, as observed using MRI. Some of the treated animals have been followed for over 8 months and show no signs of recurrence.

Animals↗

[Infection by the human immunodeficiency virus type 1 in the population of prisoners of Catalonia].

BACKGROUND: The prison population represents a high risk group for the human immunodeficiency virus type 1 infection. The present study was carried out to know the prevalence of infection in this collective in three penitentiary centers in Catalonia. METHODS: All the subjects who were in or who were admitted to the three penitentiaries for men from October 1987 to April 1988 were included in the study (n = 1,579). Demographic risk factor and penitentiary variables were obtained. The determination of anti-HIV-1 antibodies was performed by enzymoimmunoanalysis (Dupont HIV ELISA). RESULTS: The global prevalence of HIV-1 infection was of 40.6%. Significant statistical differences were found among intravenous drug users (IVDU) and non IVDU (chi 2 = 376.8, p < 0.0001, OR = 9.6, CI 95% = 7.5 - 12.3) and between habitual and sporadic users (chi 2 = 23.9, p < 0.0001, OR = 3.0, CI 95% = 1.9 x 4.7). CONCLUSIONS: The penitentiary population in Catalonia is a collective with a high prevalence of infection by the human immunodeficiency virus type 1, with intravenous drug use being the fundamental factor associated to this prevalence.

Acquired Immunodeficiency Syndrome↗

Case-finding of pulmonary tuberculosis on admission to a penitentiary centre.

SETTING: The prison population is considered to be at high risk of tuberculosis infection and illness. Therefore, a tuberculosis prevention and control program was put into effect upon the opening of a penitentiary center in Barcelona whose inmates suffered a high prevalence of intravenous drug use (IVDU) (48.4%) and HIV-1 infection (36.0%). OBJECTIVE: To ascertain the prevalence of tuberculosis infection and pulmonary tuberculosis detected on admission to jail among those prisoners who had no history of tuberculosis; and to study as predictors of tuberculosis infection and illness the variables age, IVDU and HIV-1 infection. DESIGN: Cross-sectional study. RESULTS: Of the 729 prisoners studied, 56.2% were considered infected with Mycobacterium tuberculosis. Age was the only variable associated with the infection, with an Odds Ratio (OR) of 1.017 per year (Confidence Interval [CI] 95% = 1.006-1.029) (P = 0.004). The rates of HIV-1 and M. tuberculosis co-infection, which may run between 18.9% and 21.7%, reached 42.8% in the IVDU. A 2.7% prevalence of pulmonary tuberculosis was observed. The most accurate logistic regression model for pulmonary tuberculosis diagnosis (P = 0.09) includes the variables tuberculosis infection (OR = 13.00; CI 95% = 1.7-98), IVDU (OR = 2.60; CI 95% = 0.66-7.81) and age (OR = 1.05; CI 95% = 0.99-1.11). CONCLUSION: Given the high prevalences observed, we propose the activation and maintenance of programs designed to seek out and identify cases of M. tuberculosis infection and illness within the prison population.

AIDS-Related Opportunistic Infections↗

[Hepatitis B and hepatitis delta in young inmates].

The prevalence of infection by hepatitis B (HBV) and delta (HDV) viruses and presumably related variables were evaluated in a prison for young male convicts, aged 16-21 years (n = 686), 55.1% of convicts were positive for one or more VHB markers, and 7.1% were positive for HBsAg; 89.7% of these were negative for IgM anti-HBc (chronic carriers), while 36.6% were positive for HBeAg. Anti-delta antibodies were detected in 37.5% of chronic carriers. The seropositivity of HVB markers was much higher in parenteral drug abusers (PDA) as compared with non PDA (76.3% vs 26.7%, p less than 0.0000001, OR = 8.82). Among PDA, it was higher in regular users than in occasional ones (83.3% vs 62.9%, p = 0.0001, OR = 2.95) and in those who had acquired the habit at an early age (p = 0.035). The stratified analysis also showed an association of VHB infection with other variables, basically ethical and prison-related. The possibility to develop active immunization programs is evaluated.

Adolescent↗