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Biomedical subjects

S Sanchez

Publications and source records attributed to S Sanchez.

At least 55 records · Page 3Linked to original sources
PubMed1998

Vinculin but not alpha-actinin is a target of PKC phosphorylation during junctional assembly induced by calcium.

The establishment of the junctional complex in epithelial cells requires the presence of extracellular calcium, and is controlled by a network of reactions involving G-proteins, phospholipase C and protein kinase C. Since potential candidates for phosphorylation are the tight junction associated proteins ZO1, ZO2 and ZO3, in a previous work we specifically explored these molecules but found no alteration in their phosphorylation pattern. To continue the search for the target of protein kinase C, in the present work we have studied the subcellular distribution and phosphorylation of vinculin and alpha-actinin, two actin binding proteins of the adherent junctions. We found that during the junctional sealing induced by Ca2+, both proteins move towards the cell periphery and, while there is a significant increase in the phosphorylation of vinculin, alpha-actinin remains unchanged. The increased phosphorylation of vinculin is due to changes in phosphoserine and phosphothreonine content and seems to be regulated by protein kinase C, since: (1) DiC8 (a kinase C stimulator) added to monolayers cultured without calcium significantly increases the vinculin phosphorylation level; (2) H7 and calphostin C (both protein kinase C inhibitors) completely abolish this increase during a calcium switch; (3) inhibition of phosphorylation during a calcium switch blocks the subcellular redistribution of vinculin and alpha-actinin. These results therefore suggest that vinculin phosphorylation by protein kinase C is a crucial step in the correct assembly of the epithelial junctional complex.

Actinin↗
PubMed1998

Drug-resistant tuberculosis in the Dominican Republic: results of a nationwide survey.

SETTING: The Dominican Republic. OBJECTIVE: To assess the extent of drug-resistant tuberculosis (TB) following the guidelines of the World Health Organization (WHO)/International Union Against Tuberculosis and Lung Disease (IUATLD) new global surveillance project on drug resistance in TB. METHODS: Using a multi-step proportional weighted approach, a sample of 688 sequential cases of smear positive pulmonary TB diagnosed between April 1994 and April 1995 was studied in six of the country's eight health regions. Pre-treatment sputum samples were cultured on Loewenstein-Jensen medium and drug susceptibility tests were performed using the economic variant of the proportion method. RESULTS: Of 420 cases with drug susceptibility results, resistance to one or more drugs was observed in 43.8%; resistance was found in 52.1% of 117 TB cases with a history of previous antituberculosis treatment and in 40.6% of 303 new TB cases. In five of the six health regions surveyed, > or = 41% of strains were resistant to one or more drugs. Multidrug resistance (MDR) to isoniazid and rifampicin with or without resistance to other drugs was found in 43 (10.2%) of 420 cases, including 6.6% of new TB cases. In five of the six health regions > or = 8% of strains were classified as MDR. Independent predictors of MDR-TB included being in the age group 25 to 44 years (odds ratio [OR] = 4.2, 95% confidence interval [Cl] 1.5, 11.6; P = 0.005), being aged 45 years and over (OR = 4.5, 95% CI 1.4, 14.4; P = 0.009), and having a prior history of TB (OR = 3.7, 95% CI 1.9, 7.4; P = 0.0001). CONCLUSION: The proportion of Mycobacterium tuberculosis strains resistant to one or more anti-TB drugs in the Dominican Republic is among the highest observed world-wide. The severity of the problem urgently requires the full implementation of TB control strategies endorsed by the WHO and the IUATID, which include political commitment to a National TB Program, case detection utilizing sputum-smear microscopy, directly observed treatment, regular drug supply, and standardised recording and reporting systems. Also, the sale of TB drugs in the private market should be controlled.

Adult↗
PubMed1997

SSRI-induced sexual dysfunction: fluoxetine, paroxetine, sertraline, and fluvoxamine in a prospective, multicenter, and descriptive clinical study of 344 patients.

The authors analyzed the incidence of sexual dysfunction (SD) with different selective serotonin reuptake inhibitors (SSRIs; fluoxetine, fluvoxamine, paroxetine, and sertraline) and hence the qualitative and quantitative changes in SD throughout time in a prospective and multicenter study. Outpatients (192 women and 152 men; age = 39.6 +/- 11.4 years) under treatment with SSRIs were interviewed with an SD questionnaire designed for this purpose by the authors and that included questions about the following: decreased libido, delayed orgasm or anorgasmia, delayed ejaculation, inability to ejaculate, impotence, and general sexual satisfaction. Patients with the following criteria were included: normal sexual function before SSRI intake, exclusive treatment with SSRIs or treatment associated with benzodiazepines, previous heterosexual or self-erotic current sexual practices. Excluded were patients with previous sexual dysfunction, association of SSRIs with neuroleptics, recent hormone intake, and significant medical illnesses. There was a significant increase in the incidence of SD when physicians asked the patients direct questions (58%) versus when SD was spontaneously reported (14%). There were some significant differences among different SSRIs: paroxetine provoked more delay of orgasm or ejaculation and more impotence than fluvoxamine, fluoxetine and sertraline (chi 2, p < .05). Only 24.5% of the patients had a good tolerance of their sexual dysfunction. Twelve male patients who suffered from premature ejaculation before the treatment preferred to maintain delayed ejaculation, and their sexual satisfaction, and that of their partners, clearly improved. Sexual dysfunction was positively correlated with dose. Patients experienced substantial improvement in sexual function when the dose was diminished or the drug was withdrawn. Men showed more incidence of sexual dysfunction than women, but women's sexual dysfunction was more intense than men's. In only 5.8% of patients, the dysfunction disappeared completely within 6 months, but 81.4% showed no improvement at all by the end of this period. Twelve of 15 patients experienced total improvement when the treatment was changed to moclobemide (450-600 mg/day), and 3 of 5 patients improved when treatment was changed to amineptine (200 mg/day).

1-Naphthylamine↗
PubMed1996

103Pd brachytherapy and external beam irradiation for clinically localized, high-risk prostatic carcinoma.

PURPOSE: To summarize biochemical failure rates and morbidity of external beam irradiation (EBRT) combined with palladium (103Pd) boost for clinically localized high-risk prostate carcinoma. METHODS AND MATERIALS: Seventy-three consecutive patients with stage T2a-T3 prostatic carcinoma were treated from 1991 through 1994. Each patient had at least one of the following risk factors for extracapsular disease extension: Stage T2b or greater (71 patients), Gleason score 7-10 (40 patients), prostate specific antigen (PSA) > 15 (32 patients), or elevated prostatic acid phosphatase (PAP) (17 patients). Patients received 41 Gy EBRT to a limited pelvic field, followed 4 weeks later by a 103Pd boost (prescription dose: 80 Gy). Biochemical failure was defined as a PSA greater than 1.0 ng/ml (normal < 4.0 ng/ml). Patients whose PSA was still decreasing at the last follow-up were censored at that time. Patients whose PSA plateaued at a value greater than 1.0 were scored as failures at the time the PSA first plateaued. RESULTS: The overall, actuarial freedom from biochemical failure at 3 years after treatment was 79%. In Cox proportional hazard multivariate analysis, the strongest predictor of failure was elevated acid phosphatase (p = 0.04), followed by PSA (p = 0.17), Stage (p = 0.23), and Gleason score (p = 0.6). Treatment-related morbidity was usually limited to temporary, RTOG Grade 1-2 urinary symptoms. One patient, who had both a transurethral incision of the prostate (TUIP) and a transurethral resection of the prostate (TURP), developed low-volume urinary incontinence. The actuarial potency rate at 3 years after implantation was 77% for 46 patients who were sexually potent prior to implant. CONCLUSION: Biochemical freedom from failure rates following combined EBRT and 103Pd brachytherapy for clinically localized, high-risk prostate cancer compare favorably with that reported after conventional dose EBRT alone. Morbidity has been acceptable.

Aged↗
PubMed1996

Identification of pseudohypacusis using speech recognition thresholds.

OBJECTIVE: To determine the extent to which procedural variations affect pure-tone average-spondee threshold (PTA-SRT) agreement in pseudohypacusis, to propose a theoretical framework to account for threshold differences due to procedural variations, and to devise an effective screening test for identification of pseudohypacusis. DESIGN: The subjects were normally hearing listeners who feigned a hearing loss. One experimental group received an ascending pure-tone (PT) technique combined with an ascending SRT procedure. A second experimental group received an ascending PT technique paired with a descending SRT procedure. A third experimental group received an ascending SRT procedure paired with a descending PT procedure. RESULTS: The group mean difference between the three-frequency PTA and the SRT was 10.6, 2.3, and 41.6 dB for the first, second, and third experimental groups, respectively. Comparison SRTs and PTAs from cooperative patients with hearing loss showed that a two-frequency PTA yielded a more effective test for pseudohypacusis than did a three-frequency PTA. CONCLUSIONS: The procedural differences noted in this study are consistent with a loudness bias. It is recommended that clinicians employ an ascending procedure to measure SRTs and a descending procedure to measure PT thresholds to maximize the effectiveness of a screening test for pseudohypacusis based on PTA-SRT differences.

Adult↗
PubMed1996

Protozoan infections in the male genital tract.

PURPOSE: We reviewed the literature on protozoan infections in the male genital tract, with special reference to histopathological findings and their repercussions on different andrological functions. MATERIALS AND METHODS: A literature search of the MEDLINE data base from 1966 to May 1995 was done and related articles were identified. The considered terms were parasitology and the male genital organs. Additional searches on infertility, semen and sexually transmitted diseases were performed. RESULTS: Protozoan infections of the male genital tract are rare and only a few species of parasites are involved. Trichomonas vaginalis, Trypanosoma species, Leishmania donovani, Entamoeba histolytica, Acanthamoeba species, Toxoplasma gondii and Plasmodium falciparum have been described in the male genital tract as producing testicular damage or secondary hypogonadism via hypothalamic-hypophyseal axis alterations. CONCLUSIONS: Topics of interest were the role of sexual transmission by some parasites, principally T. vaginalis, relationship with subfertility or infertility in the male subject, clinical significance in differential diagnosis with other inflammatory processes, and for some parasites the relationship with opportunistic behavior and immunodeficiency syndromes, including the acquired immunodeficiency syndrome.

Genital Diseases, Male↗
PubMed1995

Screening for active tuberculosis in HIV testing centre.

In industrialised nations HIV-seropositive individuals can be offered skin testing for tuberculosis (TB) and isoniazid prophylaxis, but this approach is neither practicable nor affordable in most developing countries. In Santo Domingo, Dominican Republic, we offered skin testing and a brief clinical examination for active TB to people requesting HIV testing at one centre. 200 newly detected HIV-positive individuals and 200 age and sex-matched HIV-negative ones were compared. 39 (9.7%) of the 400 individuals seeking HIV testing had active TB; 29 were HIV positive and 10 were HIV negative (adjusted odds ratio 3.3, 95% CI 1.3-8.7; p = 0.01). In multivariate analysis, the strongest independent predictors of active TB were 10 mm or more of induration on skin testing, a history of chronic cough, lymphadenopathy, and HIV infection. Of the patients diagnosed with TB, 85% had one or more symptoms readily ascertainable in a brief screening questionnaire. Screening for TB at HIV-testing sites could be an effective approach to early detection of active TB among not just HIV-positive but also HIV-negative people. Integrating screening for TB into HIV testing schemes could help to reduce the spread of TB and allow patients with TB to be diagnosed and treated earlier.

Adolescent↗
PubMed1995

A cluster of cases of feline dysautonomia (Key-Gaskell syndrome) in a closed colony of cats.

Twenty-five cases of feline dysautonomia (Key-Gaskell syndrome) occurred in a closed cat colony over a period of three weeks. The clinical and pathological signs were sufficiently similar to those reported during the 1982-1986 outbreak to establish a positive diagnosis. The special epidemiological and environmental circumstances of the outbreak provide a new insight into the cause(s) of the syndrome.

Animals↗
PubMed1995

Pesticide effects on eel metabolism pesticide; levels did not decline at any time when animals were exposed to 4.1 mg/liter.

Previous works on endosulfan eel toxicology in this laboratory demonstrated that 0.041 mg/liter of endosulfan was the 50% lethal concentration of 96 hr exposure. Eels of species Anguilla anguilla were exposed to two sublethal endosulfan concentrations: 8.2 micrograms/liter (1/5 LC50) and 4.1 micrograms/liter (1/10 LC50), and the experiment was done at different exposure times: 12, 24, 48, 72, and 96 hr. Muscle glycogen content decreased significantly (p < 0.05) at 24, 48, 72, and 96 hr exposure to 8.2 micrograms/liter. Muscle lactate levels in fish did not change significantly while lactate levels in eel blood increased at 12, 24, 48, 72, and 96 hr exposure to 8.2 micrograms/liter. Mean blood glucose values were elevated after exposure to both endosulfan concentrations. The results are discussed in relation to the stress effect produced by the pesticide and the related responses of the fish.

Analysis of Variance↗
PubMed1995

Pharmacological evidence for the involvement of the endogenous opioid system in the response to local inflammation in the rat paw.

We have investigated the role of the endogenous opioid system (EOS) on the inflammatory response induced by subplantar (s.p.) injection of saline (SS) and carrageenan (CA) in the hindpaw of the rat. The administration of intraperitoneal (i.p.) naloxone was used in order to unmask the effects of endogenous opiates released during peripheral inflammation. Three groups of rats received one of the following s.p. treatments: SS, CA, or no injection (NI). Pain pressure threshold (PPT), paw volume (edema) and local temperature were evaluated in baseline conditions and 3 h after treatment. In each group, the effects of i.p. vehicle, naloxone and (+)-naloxone (0.1 mg/kg) were also investigated. Both SS and CA induced a significant inflammatory response with hyperalgesia, edema and local hyperthermia. The i.p. administration of naloxone but not that of (+)-naloxone 15 min prior to testing, significantly increased edema in all groups of treatment (P < 0.05), without altering PPT or local temperature. Two-way ANOVA revealed that treatment and drugs, as well as their interaction, had a significant impact on edema which was related to the effects of CA and naloxone. Our findings illustrate the involvement of the EOS in the physiological response to local injury, regulating microvascular leakage in the inflamed tissues.

Animals↗
PubMed1995

Gentamicin formation in Micromonospora purpurea: stimulatory effect of ammonium.

The effect of ammonium on the fermentative production of gentamicin in Micromonospora purpurea has been studied using a chemically defined medium. Ammonium chloride concentrations ranging from 20 to 150 mM resulted in a proportional stimulation of growth and antibiotic formation. The use of other ammonium salts exerted a similar effect. Among the products of ammonium assimilation, glutamate and glutamine were able to exert the stimulatory effect. In addition, both amino acids reproduced the stimulation in resting cell systems of this microorganism and this result was not modified by the presence of chloramphenicol, eliminating a possible inductive action as the cause of this effect. The use of a glutamine synthetase inhibitor prevented antibiotic formation. This inhibition was reverted only by glutamine, suggesting that this amino acid was responsible of ammonium stimulation. Glutamine stimulation seems to be due to its ability to produce 2-deoxystreptamine and glucosamine, intermediates of the gentamicin biosynthetic pathway.

Ammonium Chloride↗
PubMed1994

Postprandial vascular response in patients with cirrhosis. Short-term effects of propranolol administration.

Systemic and portal hemodynamic parameters were evaluated in eight cirrhotic patients in basal conditions and after food intake and placebo. Following seven days of oral propranolol administration, hemodynamic parameters were reevaluated in the fasting and postprandial states under similar conditions. Cardiac output and portal blood flow were measured by Doppler technique. Intraobserver variability of repeated measurements was less than 10%. Food intake caused a significant increase of portal blood flow (+28%, P < 0.05). No significant changes were observed in the other hemodynamic parameters studied. Propranolol at doses achieving effective beta blockade (84 +/- 14 mg/day) (mean +/- SD) reduced portal blood flow (-24%, P < 0.05). Food intake caused a significant increase in portal blood flow (+35%, P < 0.05) in propranolol treated patients. However, in absolute values, postprandial portal blood flow during propranolol treatment was significantly lower (986 +/- 402 ml/min) than that obtained after the initial food intake (1214 +/- 537 ml/min, P < 0.05). Placebo administration had no significant hemodynamic effects in either group. This study demonstrates that chronic propranolol administration could protect from portal hemodynamic changes following food intake. Doppler technique is a reliable technique to evaluate changes on portal and systemic hemodynamic parameters during a short period of time in patients with cirrhosis.

Cardiac Output↗
PubMed1994

Vascular malformation of the cerebellopontine angle associated with "SUNCT" syndrome.

A 70-year-old man complained of two distinct types of unilateral headache during the past fifteen years. When the illness began, the pain was intermittent and short-lasting. In successive years, the crises appeared in clusters and lasted weeks to months. At present, the pain occurs daily, and is located on the right side, from the forehead supraorbitally to the temporal region. Some attacks last 30 sec and are accompanied by tearing, conjunctival injection, rhinorrhea and a subjective need to micturate. Other headaches last 1/2-1 h and are occasionally accompanied by local ipsilateral dysautonomic symptoms. Attacks of pain are provoked by movements of the trunk and neck. A vascular malformation in the right cerebellopontine angle was demonstrated on cranial CT and MRI, and by angiography.

Aged↗
PubMed1994

Comparison of a PCR-based diagnostic assay for Mycoplasma pulmonis with traditional detection techniques.

Current diagnosis of infection by Mycoplasma pulmonis, an important pathogen of laboratory rodent colonies worldwide, is based on serological, histopathological and culture techniques which can be slow and unreliable. A polymerase chain reaction (PCR) assay for M. pulmonis diagnosis was compared to current diagnostic methods. This PCR based technique allows a more specific, sensitive and rapid diagnosis of M. pulmonis from various tissues by comparison with culture and histopathology.

Animals↗
PubMed1994

Physiological studies on gentamicin: phosphate repression of antibiotic formation.

The effect of inorganic phosphate on the fermentative production of gentamicin by Micromonospora purpurea has been studied using a chemically defined medium. Phosphate concentrations higher than 5.75 mM (1 g/liter-1) did not inhibit growth but specifically prevented antibiotic formation. Changes in the pH medium and carbon or nitrogen depletion were excluded as the cause of antibiotic underproduction. The use of a phosphate analogue, a protein synthesis inhibitor and the profiles of differential rate of antibiotic production suggested that phosphate itself transiently repressed gentamicin formation. Phosphate affected the formation of 2-deoxystreptamine from 2-deoxyinosose, a none phosphorylated substrate.

Arsenates↗
PubMed1994

Diurnal fluctuations of portal and systemic hemodynamic parameters in patients with cirrhosis.

A close temporal relationship between higher levels of portal pressure during the night and the peak incidence of acute variceal bleeding has recently been demonstrated in patients with cirrhosis. Because hemodynamic changes may have a role in triggering this hemorrhagic episode, we measured systemic and portal hemodynamic parameters at 4-hr intervals for 24 hr in 12 cirrhotic patients. These results were compared with those obtained in eight healthy subjects. Cardiac output, femoral and portal blood flows were measured by Doppler technique. In cirrhotic patients, heart rate and mean arterial pressure remained constant throughout the whole study period. A marked and significant increase in portal blood flow (917 +/- 248 ml/min) (mean +/- S.D.) as compared with mesor values (649 +/- 114 ml/min, p < 0.001) was observed at midnight. This effect was accompanied by a mild but significant rise of cardiac output (from 6.5 +/- 0.7 to 6.8 +/- 0.7 l/min, p < 0.01) at 2400 hr. A significant correlation between both hemodynamic parameters was found (r = 0.78, p < 0.01). Cosinor analysis showed a significant (p < 0.05) circadian rhythm for both portal blood flow and cardiac output with an acrophase at 0050 hr. In the healthy subjects group, a significant decrease of mean arterial pressure and heart rate was observed at 2400 hr. Cosinor analysis confirmed the presence of significant rhythm for both hemodynamic parameters. In contrast with cirrhotic patients, no significant changes were observed in portal blood flow and cardiac output in healthy subjects. Our results show that in patients with cirrhosis, maximal increases in portal blood flow occur at night.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗