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Biomedical subjects

G Ramos

Publications and source records attributed to G Ramos.

At least 19 recordsLinked to original sources
PubMed2006

CYP1A1 and GSTP1 polymorphisms in an oral cancer case-control study.

CYP1A1 and GSTP1 polymorphisms have been associated with a higher risk to develop several cancers, including oral squamous cell carcinoma (OSCC), which is closely related to tobacco and alcohol consumption. Both genes code for enzymes that have an important role in activating or detoxifying carcinogenic elements found in tobacco and other compounds, and polymorphic variants of these genes may result in alterations of the enzymatic activity. The CYP1A1 gene codes for the enzyme aryl hydrocarbon hydroxylase, which is responsible for the metabolism of polycyclic aromatic hydrocarbons. The investigated polymorphism, Ile/Val, seems to increase the activity of the enzyme in homozygous individuals, leading to an accumulation of carcinogens. The Ile/Val polymorphism occurs because of an A->G transition at exon 7, resulting in the CYP1A1*2B allele. The GSTP1*B variant shows an A->G transition at exon 5, changing the amino acid Ile to Val, with a reduced catalytic activity of the enzyme. Due to this reduction, the carriers of mutant alleles lost the capability to metabolize carcinogens, which could be responsible for a higher susceptibility to cancer. We conducted a case-control study in a group of 72 cases with newly diagnosed OSCC and 60 healthy controls matched for age, gender, smoking habits, and ethnicity. We used PCR methods to identify the allelic variants CYP1A1*2B and GSTP1*B. The data obtained showed no statistically significant association of allelic or genotypic variants of CYP1A1*2B (OR = 1.06; 95% CI = 0.49-2.29) and GSTP1*B (OR = 1.40; 95% CI = 0.70-2.79) with OSCC.

Alleles↗
PubMed2005

In-depth analysis of a heterosexually acquired human immunodeficiency virus type 1 superinfection: evolution, temporal fluctuation, and intercompartment dynamics from the seronegative window period through 30 months postinfection.

Human immunodeficiency virus type 1 (HIV-1) superinfection refers to the acquisition of another strain by an already infected individual. Here we report a comprehensive genetic analysis of an HIV-1 superinfection acquired heterosexually. The infected individual was in a high-risk cohort in Tanzania, was exposed to multiple subtypes, and was systematically evaluated every 3 months with a fluorescent multi-region genotyping assay. The subject was identified in the window period and was first infected with a complex ACD recombinant strain, became superinfected 6 to 9 months later with an AC recombinant, and was monitored for >2.5 years. The plasma viral load exceeded 400,000 copies/ml during the first 9 months of infection but resolved to the set point of 67,000 copies/ml by 3 months after superinfection; the CD4 cell count was 377 cells/mul at 30 months. Viral diversity was evaluated with techniques designed to fully sample the quasi-species, permitting direct observation of the evolution, temporal fluctuation, and intercompartment dynamics of the initial and superinfecting strains and recombinants derived from them. Within 3 months of superinfection, seven different molecular forms were detected in gag and six were detected in env. The proportions of forms fluctuated widely over time in plasma and peripheral blood mononuclear cells, illustrating how challenging the detection of dually infected individuals can be. Strain-specific nested PCR confirmed that the superinfecting strain was not present until the 9 month follow-up. This study further defines the parameters and dynamics of superinfection and will foster appropriate studies and approaches to gain a more complete understanding of risk factors for superinfection and its impact on clinical progression, epidemiology, and vaccine design.

Evolution, Molecular↗
PubMed2001

Granulocyte colony-stimulating factor induces neutrophils to secrete macrophage colony-stimulating factor.

In this work we provide evidence showing that granulocytes produce macrophage colony-stimulating factor (M-CSF) from the band cell stage and secrete this factor when induced to differentiate into polymorphonuclear cells by recombinant human granulocyte colony-stimulating factor (rhG-CSF). Using an enriched population of myeloid band cells from murine bone marrow, we identified the presence of M-CSF with a chromophore-labelled monoclonal anti-M-CSF antibody. Using ELISA we detected the secretion of M-CSF in the supernatants of cultures of enriched band cells when induced with rhG-CSF to differentiate into mature neutrophils. We also found that M-CSF is the only factor responsible for the colony forming activity in the supernatants and lysates of band cells treated with rhG-CSF.

Animals↗
PubMed2001

Long term improvement in the treatment of canine leishmaniosis using an antimony liposomal formulation.

Pharmacokinetic and clinical effectiveness of liposome-encapsulated N-methylglucamine antimoniate (LMA) was performed in dogs suffering from experimental leishmaniosis. LMA was compared with N-methylglucamine antimoniate (MGA), the same drug in its free form. Sb plasma concentrations for LMA were always higher than those for MGA. Mean residence time (MRT), half-life time (t(1/2)) and clearance (Cl) showed that Sb was eliminated slower after liposome administration. The high volume of distribution (Vd) obtained with LMA suggests that Sb could achieve therapeutic concentrations in parasite-infected tissues. Average plasma concentration at steady state (Css(ave)) shows that Sb body concentrations after LMA treatment (9.8 mg/kg Sb, each 24h) would be effective in Leishmania infantum canine infection. Comparing LMA with MGA in a 1-year follow-up we observed no relapses for LMA and total protein and gammaglobulin concentrations were within normal range, while for MGA both began to rise 3 months after treatment. Use of antimonial liposomal formulations may restore effectiveness to an existing drug and reduce toxicity.

Animals↗
PubMed2001

Hydatid cyst of the lung: diagnosis and treatment.

Hydatid infestation of the lung can be primary or secondary. In three of four cases the cyst is a single one. Hydatidosis of a different location, particularly the liver, may be associated. The period of initial growth of primary hydatidosis is frequently asymptomatic. Bronchial fistulization is an important event in the evolution of the cyst. Intrapleural rupture constitutes a rare eventuality, but it is often as characteristic as it is severe. Secondary, metastatic hydatidosis, due to breaking of a primary visceral cyst in a vein or heart, is rare. A special form is so-called multiple malignant pulmonary hydatidosis, which causes progressive respiratory deficiency and right ventricular failure. There are a variety of radiographic images. Ultrasonography, computed tomography, and magnetic resonance imaging can recognize certain details of the lesions and discover others that are not visible by conventional radiography. For a specific serologic diagnosis, our experience favors the immunoglobulin G enzyme-linked immunosorbent assay and immunoelectrophoresis. Treatment is essentially surgical. In general, chemotherapy is used as a complement to operative treatment to avoid recurrence. Surgery has two objectives: to remove the parasite and to treat the bronchipericyst pathology and other associated lesions. The prognosis has changed during the last few years, and results are now commonly satisfactory. The most frequent complications are pleural infection and prolonged air leakage. Operative mortality does not exceed 1% to 2%. Despite the low mortality and the limited recurrence rate, it is necessary to remember the invading character of pulmonary hydatid disease, which sometimes makes therapy difficult and questionable. Prophylaxis is essential to eradicate the disease completely.

Animals↗
PubMed2000

The Ibizian hound presents a predominantly cellular immune response against natural Leishmania infection.

Veterinarians working in the Balearic Islands (Mallorca), an endemic region of canine leishmaniosis, have reported very few cases of leishmaniosis in Ibizian hounds while concurrently observing that dogs of other breeds had a high incidence of clinical canine leishmaniosis. To further investigate this observation, two populations of dogs from the Balearic Islands were examined for the presence of Leishmania-specific cellular immunity using a delayed type hypersensitivity test (DTH) to leishmanin and for the presence of Leishmania-specific humoral immunity using an ELISA. Fifty-six asymptomatic dogs, 31 Ibizian hounds and 25 dogs belonging to other breeds were examined. Seventy-seven percent of the dogs demonstrated a specific immune response against Leishmania, either humoral or cellular. This finding suggests that the infection rate (77%) was higher than previously considered. For Ibizian hounds 81% were DTH positive while only 48% of the other dogs were DTH positive. A statistical association between Ibizian hounds and positive DTH response was found. A specific humoral response was found in 48% of Ibizian hounds and in 56% of the other dogs. No statistical association relative to the Leishmania-specific IgG1 and IgG2 levels were found between the two groups. The Ibizian hound has been reported to be more resistant to Leishmania infection and we found that the Ibizian hound mounts a significant cellular response to infection. Thus, the Ibizian hound may be an interesting canine model for the investigation of protective anti-Leishmania immune response.

Animals↗
PubMed2000

Prognostic factors in neuroendocrine lung tumors: a Spanish Multicenter Study. Spanish Multicenter Study of Neuroendocrine Tumors of the Lung of the Spanish Society of Pneumonology and Thoracic Surgery (EMETNE-SEPAR).

BACKGROUND: This study examines the experience of the Spanish Multicenter Study of Neuroendocrine Tumors of the Lung through the clinical data and behavior of patients treated for this pathologic process. METHODS: From 1980 to 1997, 361 cases of neuroendocrine carcinomas (NEC) were treated surgically. Patients were enrolled in a protocol using the pathologic and follow-up reports. According to Dreslers' criteria, the cases were segregated into grade 1 (typical carcinoid), grade 2 (atypical carcinoid), grade 3 large cell type, and grade 3 small cell type. Several variables were reviewed in all patients. Statistical analysis was performed to determine whether clinical characteristics and differentiation were associated with significant differences in the prognosis. RESULTS: A total of 261 cases of NEC were identified with grade 1, 43 with grade 2, and with grade 3: 22 of large and 35 of small cells. Five-year survival for different grades was as follows: grade 1, 96%; 2, 72%; 3 large cell type, 21%; and 3 small cell type, 14%. When a comparative analysis between typical and atypical carcinoids was performed a significant difference for mean age, tumor size, nodal metastases, and recurrence was observed. However, female sex, nodal metastases, and recurrence rate differed between atypical carcinoids and grade 3 NEC of large cells. A difference in recurrence rate was found between patients with both types of grade 3 NEC. CONCLUSIONS: The progressive deterioration of tumor organization highlights that neuroendocrine tumors constitute a continuous spectrum. A careful observation of pathologic findings is necessary to individualize their prognostic factors.

Adult↗
PubMed2000

[Surgical treatment of lung cancer: comparative assessment of the staging systems of 1986 and 1997. Results in 500 consecutive patients].

OBJECTIVE: To evaluate the influence of different variables on survival in relation to the staging guidelines of 1986 and 1997. PATIENTS AND METHODS: Five hundred patients (473 men and 27 women) with non-small cell lung cancer were treated surgically from 1980 to 1997. Resections performed: 184 lobectomies, 16 bi-lobectomies, 244 pneumonectomies, 2 bronchoplastic lobectomies, and 54 segmentectomies. HISTOLOGY: 338 epidermoid, 86 adenocarcinoma, 40 giant cell, 36 mixed tumor. Differentiation: 216 N1, 91 N2, 193 N3. Stages according to 1986 guidelines were I: 246 (49.2%) (T1: 32, T2: 214); II: 27 (5.4%); IIIa: 197 (39.4%) (N0: 84; N1: 2; N2: 111); IIIb: 23 (4.6%) (N0: 12; N2: 11); and IV: 7 (1.4%) (N0: 4; N2: 3). Stages according to the 1997 guidelines were used for comparison of survival between patients with Ia and Ib tumors and with IIb and IIIa tumors. RESULTS: With follow-up periods ranging from 2 to 17 years, 141 patients (28%) were alive, 26 (5%) were lost to follow-up and 333 had died. Two patients (0.4%) died during surgery and 36 (7.2%) died during the postoperative period. Among the remaining 462 patients, 295 deaths were related to the following causes: metastasis in 130 cases (44%), recurrence in 81 cases (27%), functional causes in 17 (6%), independent causes in 54 (18%) and unknown causes in 13 (4%). Overall survival rates at 5 and 10 years were 36 and 26%, respectively; survival rates by histological type: epidermoid 36 and 26%, adenocarcinoma 35 and 26%; stage I, 51 and 41% (Ia, 81 and 75%; Ib, 44 and 33%); IIIa 24 and 15% (IIb of 1997: 27 and 17%; IIIa of 1997: 20 and 13%). Survival by N factor: N0, 44 and 34%; N2, 17 and 8% (1986) and 17 and 11% (1997). CONCLUSIONS: Survival agrees with other studies. The 1997 staging guidelines are useful for differentiating survival between stages Ia and Ib and between IIb and IIIa. N and T factors, histology and stage influence the appearance of metastasis; T factor influences recurrence.

Adult↗
PubMed2000

[Mediastinal hydatid cysts: 8 cases].

Hydatidosis in humans is a parasitic disease produced by cystic growth of the larvae of the tapeworm Echinococcus granulosus, affecting mainly the liver and lung. Larvae are rarely present in the mediastinum, although approximately 100 cases have been described in the literature. We report eight cases of hydatid cysts of the mediastinum (HCM) treated surgically over a period of 21 years. The incidence was similar in males and females and ages ranged from 10 to 74 years. Symptoms depend on size, location and involvement of neighboring structures in HCM. The most serious complication is cyst rupture with consequent transfer of hydatid material to the blood, possibly causing anaphylactic shock and even death. Currently, sonography, computed tomography and magnetic resonance images facilitate diagnosis. Treatment involves excision of the cyst and peri-cystic tissue. CHM should be suspected when mediastinal cysts are found in countries where the incidence of hydatidosis is high.

Adolescent↗
PubMed2000

Effect of inhibition of cyclooxygenase on pre- and postjunctional actions of peroxides in the iris-ciliary body.

In the present study, we investigated the effect of inhibition of cyclooxygenase (COX) with flurbiprofen (FBF) on peroxide-induced enhancement of field-stimulated [3H]norepinephrine ([3H]NE) release from bovine isolated irides. Furthermore, the effect of FBF was examined on peroxide-induced attenuation of contractions evoked by carbachol on this tissue. Irides were prepared for studies of neurotransmitter release and for measurement of contractile tension in vitro. Pretreatment of tissues with FBF (10 microM) caused significant (P < 0.001) rightward shifts of concentration-response curves to H2O2 and also decreased cumene hydroperoxide (cuOOH)-induced enhancement of evoked [3H]NE release. FBF (10 microM) partially prevented the attenuation of carbachol-induced contractions induced by H2O2 (300 microM) and cuOOH (300 microM). We conclude that inhibition of the biosynthesis of prostanoids reduced both the prejunctional stimulatory effects of H2O2 and cuOOH on sympathetic neurotransmission and inhibitory effects of peroxides on carbachol-induced contractions the in the bovine isolated iris.

Animals↗
PubMed2000

[Assessment of mediastinal tumor involvement (T factor) in lung cancer with transesophageal ultrasonography].

UNLABELLED: Transesophageal sonography was originally used to assess esophageal-gastric neoplasm. The technique may also be useful in the evaluation of pulmonary neoplasms for possible mediastinal involvement, with regard to both T and N factors. OBJECTIVE: To consider the validity of this minimally-invasive technique for assessing possible mediastinal involvement by direct tumoral invasion (T4) and to help obtain the most accurate staging of lung cancer. PATIENTS AND METHODS: Sixteen patients with confirmed histopathological diagnoses of pulmonary neoplasm were examined by transesophageal sonography in order to evaluate possible mediastinal involvement. They had previously been classified by computed tomography as T4 (12 patients) or possible T4 (4 patients). Mediastinal involvement was also assessed by mediastinotomy or thoracotomy in 15 of the 16 patients. RESULTS: Transesophageal sonography revealed mediastinal involvement in eight of the 16 patients; the rest had no such involvement. Surgical exploration of the mediastinum confirmed involvement in seven of those who had been so classified by sonography (with the remaining patient not having been assessed surgically). Among the eight patients who were considered free of mediastinal involvement, there was in fact none, although we found previously undetected infiltration of the posterior surface of the right pulmonary artery in one patient. Sensitivity was 87.5%, specificity 100% and accuracy 93.3%. CONCLUSION: Transesophageal ultrasound is a diagnostic tool that can provide additional information to complement other diagnostic strategies.

Echocardiography, Transesophageal↗
PubMed1999

Evaluation of six serological tests in diagnosis and postoperative control of pulmonary hydatid disease patients.

Latex agglutination (LA), passive hemagglutination (PHA), immunoelectrophoresis (IEP) and specific IgE, IgM, IgG enzyme-linked immunosorbent assay (ELISA) tests for diagnosis and postoperative follow-up of 79 patients with surgically confirmed pulmonary hydatidosis were evaluated. Specific IgG ELISA was the most sensitive test (83.5%) and the least sensitive tests were specific IgE ELISA (44.3%) and IEP (50.6%). The specificity obtained for all the serologic test was above 97% in all cases. The greatest number of false positives in all tests (except IEP) occurred in patients with Taenia saginata and Taenia solium cysticerci infestations and in patients with lymphoma and leukemia. Specific IgG ELISA demonstrated the highest negative predictive value (93.8%). No statistically significant differences (p > 0.050) were found in the sensitivity of the tests when patients with only one cyst and patients with various cysts were compared. Considering only the patients without relapse, the percentage of seropositive patients increased in all tests at 1 and 3 months after surgery. After that time the percentage of seropositive patients decreased. At 48 months after surgery all patients without relapse became negative in IEP, specific IgE ELISA, and specific IgM ELISA. The antibody titers in all seropositive patients increased during the 3 months after surgery. From these 3 months onward, antibody levels decreased in all serologic tests studied in the group of patients without relapse. The patients who had relapses during the first year after surgery presented persistently elevated antibody titers in all postoperative sera. The antibody titers of the patients who relapsed between the third and fourth years after surgery decreased progressively the third month after surgery, and increased in the serum obtained at the moment of relapse diagnosis. Our results show that persistence of elevated antibody titers in patients with pulmonary hydatidosis in the year after surgery or titer increase after a progressive decrease are indicative of relapse or reinfection.

Antibodies, Helminth↗
PubMed1999

In-vitro comparative activity of UR-9825, itraconazole and fluconazole against clinical isolates of Candida spp.

UR-9825 is a new broad-spectrum triazole antifungal agent with a good pharmacokinetic profile and excellent bioavailability. It shows high in-vitro activity and efficacy in models of systemic candidosis in rats and rabbits, comparing favourably with fluconazole. The purpose of this study was to evaluate the in-vitro activity of UR-9825 and to compare it with that of fluconazole and itraconazole against 283 clinical isolates of Candida spp. UR-9825 was more potent against Candida spp. than both fluconazole and itraconazole, even against some Candida albicans and Candida krusei isolates with decreased susceptibility to fluconazole (MIC 16 mg/L).

Antifungal Agents↗
PubMed1998

Open-window thoracostomy and thoracomyoplasty to manage chronic pleural empyema.

BACKGROUND: The purpose of this study is to report our 15-year experience treating chronic empyemas after pulmonary resection and tuberculosis. METHODS: Open-window thoracostomy and thoracomyoplasty were used to treat 40 patients with chronic pleural empyema characterized by residual empyematic cavity, bronchopleural fistula, and persistent pleural infections that were secondary to tuberculosis (n = 22) or pulmonary resection (n = 18). Between 2 and 7 months after thoracostomy, thoracomyoplasty was performed to eliminate a persistent pleural cavity. In 2 patients with postpulmonary resection empyema and a large bronchopleural fistula, intrathoracic transposition of the latissimus dorsi flap and open-window thoracostomy were performed simultaneously to close the fistula. RESULTS: The pleural space was eliminated per primam intentionem in 21 of 22 patients with tuberculosis and in 14 of 18 with a postpulmonary resection empyema. Another myoplasty was performed in an additional 3 patients to eliminate the pleural space. During open-window thoracostomy, the latissimus dorsi muscle was preserved with minimal injury to the anterior serratus muscle. One patient died postoperatively. CONCLUSIONS: Successful treatment of chronic pleural empyema requires adequate timing of surgical procedures. Our two-procedure technique is relatively simple and safe.

Adolescent↗
PubMed1998

Comparison of broth microdilution method using Haemophilus test medium and agar dilution method for susceptibility testing of Eikenella corrodens.

Susceptibility testing of Eikenella corrodens is usually performed by a Mueller-Hinton sheep blood agar dilution (AD) method. However, this method is impractical for testing only a few strains. We compared AD with the broth microdilution method using Haemophilus test medium (HTM) in order to determine the susceptibility of 36 clinical isolates of E. corrodens to eight antimicrobial agents. MICs obtained by the HTM method yielded 95.5 and 84% agreement (within 2 and 1 log2 dilutions, respectively) with those obtained by AD. The HTM method with incubation in CO2 for 48 h was highly reproducible and constitutes an easy alternative for antimicrobial susceptibility testing of E. corrodens.

Agar↗
PubMed1998

[Estimating height and body weight from knee height and mid arm circumference in children 9 to 14 years old].

Some individuals with functional limitations or in some clinical or field areas have troubles to get stature and body weight measurement done. It does exist the alternative of estimating these variables from measurements of body segments like knee height (KH) and mid arm circumference (MAC). Of a sample of 113 healthy Venezuelan children, both sexes, 9 to 14 years of age, equations suggested by Ross Laboratories for estimating stature and body weight were applied. It was concluded that the need for an adjustment was evident which done using multiple regression analysis. This allowed us to generate estimated stature an weight by KH and MAC tables, for Venezuelan children.

Adolescent↗
PubMed1997

Primary hepatic non-Hodgkin's lymphoma in children: a case report and review of the literature.

Non-Hodgkin's lymphomas presenting exclusively in the liver are rather uncommon in adults and extremely rare in children. We describe a six-year-old white boy with jaundice, abdominal pain, and weight loss of two weeks duration. Physical examination disclosed asthenia, jaundice, abdominal swelling, large hepatomegaly, and ascitis. Aminotransferases bilirubin, and alkaline phosphatase were significantly elevated. Bone marrow aspiration, cerebrospinal fluid, chest x-ray, renal function tests, and uric acid were normal. Abdominal ultrasound showed liver enlargement with irregular regular borders, many parenchymal nodules in both liver lobes, a large hypoechogenic mass in the inferior segment of the liver, normal biliary ducts and two pancreatic nodules resembling those in the liver. Liver needle biopsy disclosed diffuse lymphomatous infiltration. Blast cells were positive for leukocyte common antigen (CD 45). Immunohistochemistry study for T or B cell lineage differentiation was not done. The child showed an excellent response to chemotherapy based on the BFM-83 protocol for B cell non-Hodgkin's lymphomas. The patient had his therapy discontinued in June 1995 and remains in first complete remission as of May 20th, 1996.

Child↗