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Biomedical subjects

J Gonzalez

Publications and source records attributed to J Gonzalez.

At least 37 records · Page 2Linked to original sources
PubMed2002

Bronchial bacterial colonization in patients with resectable lung carcinoma.

The pattern and clinical implications of bronchial bacterial colonization have been widely investigated in patients with chronic lung disease, particularly chronic obstructive pulmonary disease. The main aim of this study was to determine the frequency and risk factors for bronchial colonization in lung cancer patients who have undergone surgical resection. Forty-one patients with resectable lung cancer (22 (54%) active smokers, 52+/-23 pack-yrs) with a mean forced expiratory volume in one second of 80+/-16% predicted, were studied with bilateral protected specimen brush and lung tissue biopsy during the surgical procedure. Quantitative bacterial culture, susceptibility tests and histological examination of samples were performed. Bronchial colonization with > or = 1 potential pathogenic micro-organism was found in 17 of 41 (41%) patients. The most frequent strains isolated were: Haemophilus influenzae (35%), Streptococcus pneumoniae (13%) and Pseudomonas spp. (9%). The risk factors for bronchial colonization were central location of the tumour (odds ratio (OR)=9.2, confidence interval (CI) 95%=2.1-39.6, p=1.003) and increased body mass index (OR=1.6, CI 95%=1.2-2.2, p=0.005). The frequency of postoperative infectious pulmonary complications was low (five cases (12%)) and no relationship was observed with bronchial colonization. Patients with resectable lung carcinoma had a high rate of bronchial colonization (41%), mainly with potential pathogenic microorganisms. The independent risk factors for colonization in these patients were central location of the tumour and a high body mass index.

Aged↗
PubMed2001

Identification of alkylidene hydrazides as glucagon receptor antagonists.

High throughput screening of our small molecule combinatorial library identified a class of benzoylnaphthalenehydrazones with modest affinity for the human glucagon receptor. Optimization of this initial hit through a series of targeted libraries and traditional medicinal chemistry led to ligands with nanomolar affinities. Pharmacological evaluation demonstrated that these ligands were competitive glucagon receptor antagonists. Intravenous administration of a representative benzoylnaphthalenehydrazone into rats attenuated glucagon-stimulated glucose levels.

Animals↗
PubMed2001

A randomized trial of the discontinuation of primary and secondary prophylaxis against Pneumocystis carinii pneumonia after highly active antiretroviral therapy in patients with HIV infection. Grupo de Estudio del SIDA 04/98.

BACKGROUND: Prophylaxis against Pneumocystis carinii pneumonia is indicated in patients with human immunodeficiency virus (HIV) infection who have less than 200 CD4 cells per cubic millimeter and in those with a history of P. carinii pneumonia. However, it is not clear whether prophylaxis can be safely discontinued after CD4 cell counts increase in response to highly active antiretroviral therapy. METHODS: We conducted a randomized trial of the discontinuation of primary or secondary prophylaxis against P. carinii pneumonia in HIV-infected patients with a sustained response to antiviral therapy, defined by a CD4 cell count of 200 or more per cubic millimeter and plasma HIV type 1 (HIV-1) RNA level of less than 5000 copies per milliliter for at least three months. Prophylactic treatment was restarted if the CD4 cell count declined to less than 200 per cubic millimeter. RESULTS: The 474 patients receiving primary prophylaxis had a median CD4 cell count at entry of 342 per cubic millimeter, and 38 percent had detectable HIV-1 RNA. After a median follow-up period of 20 months (758 person-years), there had been no episodes of P. carinii pneumonia in the 240 patients who discontinued prophylaxis (95 percent confidence interval, 0 to 0.85 episode per 100 person-years). For the 113 patients receiving secondary prophylaxis, the median CD4 cell count at entry was 355 per cubic millimeter, and 24 percent had detectable HIV-1 RNA. After a median follow-up period of 12 months (123 person-years), there had been no episodes of P. carinii pneumonia in the 60 patients who discontinued prophylaxis (95 percent confidence interval, 0 to 4.5 episodes per 100 person-years). CONCLUSIONS: In HIV-infected patients receiving highly active antiretroviral therapy, primary and secondary prophylaxis against P. carinii pneumonia can be safely discontinued after the CD4 cell count has increased to 200 or more per cubic millimeter for more than three months.

AIDS-Related Opportunistic Infections↗
PubMed2001

Massive plasmocytosis due to methimazole-induced bone marrow toxicity.

Pancytopenia is a rare complication of the thionamide therapy reported secondary to aplastic anemia, the bone marrow being invariably hypocellular. We present a case of a 16-year-old female with Graves' disease who presented with massive bone marrow plasmocytosis mimicking multiple myeloma. The patient had already been on methimazole for a month when she was admitted to the Pediatric Unit with the diagnosis of sepsis. CBC revealed pancytopenia. Bone marrow aspirations showed hypocellular-normocellular bone marrow, 98% of plasma cells. At that time, MMI was discontinued and the patient was started on broad-spectrum antibiotics, dexamethasone, and G-CSF. Bone marrow aspiration day +4 still showed hypo-normocellular marrow, with remaining 6% plasma cells. Myeloma screen was negative; ANC >1,000 at day +7, platelets >50,000 at day +24. Twenty-four months after patient's discharge, her clinical condition, CBC, and bone marrow remained normal. To our knowledge this is the first report of pancytopenia due to MMI, where the usual hypoplasia found is replaced by massive plasmocytosis.

Adolescent↗
PubMed2001

Signatures of hippocampal oxidative stress in aged spatial learning-impaired rodents.

Neurons and glia within the hippocampus of aged, spatial learning-impaired Long-Evans rats exhibit uniquely altered gene expression profiles, and we have postulated oxidative stress as the basis for this. To test this hypothesis we quantitated the extent of protein and nucleic acid oxidative damage, evaluated the status of mitochondrial DNA integrity, and examined several signaling entities and molecular indicators frequently associated with oxidative stress and gliosis. Immunoblotting demonstrated elevated heme oxygenase-1 in the aged-impaired hippocampus and immunocytochemistry suggested that heme oxygenase-1 is largely cytosolic and at least partly neuronal in nature. In the aged-impaired group, immunoreactivity to 8-hydroxy-2'-deoxyguanosine, an oxidative nucleic acid adduct, was found to be elevated in the dentate gyrus and in area CA1 of the hippocampal formation. Isolated mitochondrial DNA was found to be significantly damaged in the aged-impaired group. In the aged learning-impaired rats only, proteins in a 65-kDa band were found to contain excessive levels of carbonyl residues. Glial activation was examined by in situ hybridization histochemistry to tumor necrosis factor alpha and by immunocytochemistry with OX-6, which detects activated microglia. White matter in aged brains exhibited a modest up-regulation of tumor necrosis factor alpha mRNA and OX-6 immunoreactivity, but the hippocampal formation expressed tumor necrosis factor alpha mRNA equivalent to young animals and few OX-6-positive microglia. The mRNA for manganese-dependent superoxide dismutase, which is elevated in the aged hippocampus, was found preferentially expressed in neurons. We conclude that aged hippocampal neurons appear to be under oxidative stress and this is more severe in the learning-impaired subjects, suggesting a possible basis for age-induced cognitive decline.

Aging↗
PubMed2001

Prospective comparison of arm veins and greater saphenous veins as infrageniculate bypass grafts.

OBJECTIVES: to compare arm and saphenous veins for infrageniculate bypass grafting. DESIGN: prospective non-randomised study. MATERIALS: two hundred patients, of which 197 had ischaemic tissue loss or rest pain. METHODS: two hundred and eleven infrageniculate vein bypass procedures using 176 greater saphenous veins and 35 arm veins. RESULTS: the cumulative primary graft patency rate at 1-month and 2 years was 80% and 61% for saphenous vein and 89% and 42% for arm vein. The corresponding rates for secondary patency were 84.5% and 68%, and 91% and 57%, respectively. These results corresponded to a relative risk of secondary failure of 1.53 (95% CI 0.71, 3.31) for arm vein grafts. In subgroup analyses, this estimate was 0.93 and 2.1 for primary vs secondary bypasses and 0.38 and 2.06 for single-vein vs spliced-vein bypasses. Among arm veins, cephalic vein grafts performed better than basilic vein grafts. Early mortality was 14% for arm vein and 10% for saphenous vein. CONCLUSION: in the setting of infrageniculate bypass grafting, arm vein grafts are not equivalent to greater saphenous vein grafts, but contribute importantly to a policy of using autologous veins. The possibility of equivalence remains for the arm vein graft that uses a cephalic vein or is a primary procedure.

Aged↗
PubMed2001

Feasibility of photopheresis to reduce the occurrence of restenosis after percutaneous transluminal coronary angioplasty: a clinical pilot study.

BACKGROUND: Photopheresis was evaluated as a means of preventing restenosis on the basis of immune modulation. METHODS: This was a prospective, randomized, controlled clinical trial analyzing clinical restenosis at 6 months after percutaneous transluminal coronary angioplasty (PTCA). Seventy-eight patients with single-vessel angioplasty were randomly assigned to a control group of 41 patients and a treatment group of 37 patients. At 6 months, there were 72 evaluable patients: 39 control patients and 33 treated. Twenty-nine control patients received balloon PTCA only and 10 patients received stents. Twenty treated patients received PTCA only and 13 patients received stents. Baseline clinical characteristics of both groups were similar. The treatment group received photopheresis for a total of 5 treatments. Primary end points were death from any cause, myocardial infarction, ischemia, and repeat revascularization procedures. RESULTS: By intention-to-treat analysis, clinical restenosis occurred in 27% of control patients versus 8% of treated patients (P =.040, relative risk = 0.30). CONCLUSIONS: Photopheresis therapy in patients undergoing balloon PTCA with and without stent deployment has been shown to be effective in reducing restenosis. The use of photopheresis in such patients merits further investigation.

Adolescent↗
PubMed2001

The effect of MPEG audio compression on multidimensional set of voice parameters.

The MPEG-1 Layer 3 compression schema of audio signal, or commonly known as mp3, has caused a great impact in recent years as it has reached high compression rates while also conserving a high sound quality. Previous listening tests have shown that music and speech samples compressed at high bitrates are virtually indistinguishable from the original samples, but very little is known about how compression acoustically affects the voice signal. In Experiment 1 the spectral composition of original and compressed speech signals were analyzed by means of the Long-Term Average Spectrum using the Computerized Speech Laboratory (Kay Elemetrics Corp. (Pine Brook, NJ, USA)). In Experiment 2 a set of 29 voice parameters extracted by using the Multidimensional Voice Program of Kay are compared between original and compressed voices at different bitrates. Results show a high fidelity at high-bitrate compressions (128 and 160 kbit per second (kbps)) both in voice parameters and the amplitude-frequency spectrum. Compressions at 64 kbps or lower bitrates introduces substantial modifications in the voice signal, seriously altering parameters related with tremor, amplitude perturbation, noise, subharmonics and voice irregularities, likewise the signal spectrum is altered in its high frequency region.

Adult↗
PubMed2001

The nursing shortage revisioning the future.

A severe shortage of nurses is being experienced nationally and globally. In South Florida, one of the most severely impacted regions in the world, a group of healthcare organizations, educational institutions, and nursing organizations formed the Nursing Shortage Consortium to combat the nursing shortage. Strategic efforts to recruit and retain nurses are underway, with a focus on nurturing interest among young people and increasing opportunities to stimulate their interest, to increase the supply of appropriately prepared professional nurses.

Advertising↗
PubMed2001

Initial bacterial colonization in patients admitted to a respiratory intensive care unit: bacteriological pattern and risk factors.

BACKGROUND: Colonization is an important risk factor for consecutive infection, but little is known about incidence and initial pattern on admission to respiratory intensive care units (RICU). OBJECTIVE: To study the bacterial colonization during the first 24 h after admission to a RICU. METHODS: Endotracheal aspirates, gastric juice, and pharyngeal and rectal swabs of 55 consecutive patients were cultured (45 men, age 66 +/- 14 years, APACHE II 20.1 +/- 5.6, no parenchymal infection). All samples were taken within the first 24 h after admission to a RICU. Potentially pathogenic microorganisms were grouped as community (c-PPM) and hospital acquired (h-PPM), and risk factors for colonization of each body site as well as for overall colonization (all sites excluding rectum) were identified by logistic regression analysis. RESULTS: The trachea was colonized in 18% of the intubated patients with c-PPMs and in 11% with h-PPMs. Candida spp. were the most frequent c-PPMs isolated from trachea, pharynx, and stomach (excluding rectal swabs), and Pseudomonas aeruginosa was the most frequently isolated h-PPM in trachea. The incidence of overall colonization was 49% for c-PPMs (predominantly Escherichia coli) and 18% for h-PPMs (predominantly P. aeruginosa). Admission to the hospital > or = 48 h before ICU admission was an independent risk factor of colonization with h-PPMs in univariate (33 vs. 7%, p = 0.015) and multivariate analyses (odds ratio 7.2, 95% CI 1.4-38.3; p = 0.0197). CONCLUSIONS: Colonization of the trachea with c-PPMs was already present in every 5th and with h-PPMs in every 10th intubated patient during the first 24 h of RICU admission even in the absence of parenchymal infections. Hospitalization more than 48 h prior to RICU admission was a risk factor of colonization with h-PPMs.

Aged↗
PubMed2001

Reappraisal of the aetiology and prognostic factors of severe acute respiratory failure in HIV patients.

The introduction of highly active antiretroviral therapy with protease inhibitors in 1996 has changed the morbidity and mortality of acquired immune deficiency syndrome patients. Therefore, the aetiologies and prognostic factors of human immunodeficiency virus (HIV)-infected patients with life-threatening respiratory failure requiring intensive care unit (ICU) admission need to be reassessed. From 1993 to 1998, we prospectively evaluated 57 HIV patients (mean+/-SEM age 36.5+/-1.3 yrs) admitted to the ICU showing pulmonary infiltrates and acute respiratory failure. A total of 21 and 30 patients were diagnosed as having Pneumocystis carinii and bacterial pneumonia, respectively, of whom 13 and eight died during their ICU stay (p=0.01). Both groups of patients had similar age, Acute Physiology and Chronic Health Evaluation (APACHE) II score, and severity in respiratory failure. The number of cases with bacterial pneumonia admitted to ICU decreased after 1996 (p=0.05). Logistic regression analysis showed that (APACHE) II score >17, serum albumin level <25 g.(-1), and diagnosis of P. carinii pneumonia were the only factors at entry associated with ICU mortality (p=0.02). Patients with bacterial pneumonia are less frequently admitted to the intensive care unit after the introduction of highly active antiretroviral therapy with protease inhibitors in 1996. Compared to the previous series, it was observed that the few Pneumocystis carinii pneumonia patients that need intensive care still have a bad prognosis.

AIDS-Related Opportunistic Infections↗
PubMed2001

Unsupported valvuloplasty in children with congenital mitral valve anomalies. Late clinical results.

OBJECTIVE: To analyze late clinical evolution after surgical treatment of children, with reparative and reconstructive techniques without annular support. METHODS: We evaluated 21 patients operated upon between 1975 and 1998. Age 4.67+/-3.44 years; 47.6% girls; mitral insufficiency 57.1% (12 cases), stenosis 28.6% (6 cases), and double lesion 14.3% (3 cases). The perfusion 43.10+/-9.50 min, and ischemia time were 29.40+/-10.50 min. The average clinical follow-up in mitral insufficiency was 41.52+/-53.61 months. In the stenosis group (4 patients) was 46.39+/-32.02 months, and in the double lesion group (3 patients), 39.41+/-37.5 months. The echocardiographic follow-up was in mitral insufficiency 37.17+/-39.51 months, stenosis 42.61+/-30.59 months, and in the double lesion 39.41+/-37.51 months. RESULTS: Operative mortality was 9.5% (2 cases). No late deaths occurred. In the group with mitral insufficiency, 10 (83.3%) patients were asymptomatic (p=0.04). The majority with mild reflux (p=0.002). In the follow-up of the stenosis group, all were in functional class I (NYHA); and the mean transvalve gradient varied between 8 and 12 mmHg, average of 10.7 mmHg. In the double lesion group, 1 patient was reoperated at 43 months. No endocarditis or thromboembolism were reported. CONCLUSION: Mitral stenosis repair has worse late results, related to the valve abnormalities and associated lesions. The correction of mitral insufficiency without annular support showed good long-term results.

Adolescent↗
PubMed2000

Preoperative induction chemotherapy followed by concurrent chemoradiotherapy in advanced carcinoma of the oral cavity and oropharynx.

BACKGROUND: Combined modality therapy plays a central role in the management of advanced head and neck tumors. The objective of our Phase II study was to determine the feasibility, toxicity, and clinical and pathologic response of preoperative induction chemotherapy, followed by concurrent chemoradiotherapy in patients with Stage III or IV squamous cell carcinoma according to the American Joint Committee on Cancer Staging of the oral cavity and oropharynx with no distant metastases. METHODS: After staging, 62 patients with locally advanced carcinoma of the oral cavity and oropharynx were treated preoperatively with chemotherapy (1 cycle of cisplatin and 5-fluorouracil [P-5FU]) followed by concurrent chemoradiotherapy (3 cycles of P-5FU combined with radiotherapy, 60 grays [Gy] given in 33 fractions of 1.8 Gy). After evaluation, patients underwent surgery either as a diagnostic (biopsy) or therapeutic procedure (resection of the primary tumor and/or the neck). Surgery was performed with the intent to spare organ function. RESULTS: Grade 3-4 mucositis was observed in 37 patients (59%). Overall clinical response was obtained in 87%, and the complete clinical response rate was 50%. Surgery was performed in 53 patients, 50 at the primary tumor site (11 biopsies, 14 marginal excisions, and 25 wide excision) and 46 patients had neck dissection. Pathologic complete remission was observed in 29 patients (46%). After a median follow-up of 39 months, locoregional control rate was 76%, estimated 3-year disease free survival rate was 73% (+/- 4%), and estimated 3-year overall survival rate was 76% (+/- 4%). CONCLUSIONS: This intensive multimodality treatment is feasible, and toxicity is significant but tolerable. The treatment results appear promising and durable. Organ-preserving surgery can be performed in many patients.

Adult↗
PubMed2000

Kinematics of electrons near a van hove singularity

A two-dimensional electronic system, where the Fermi surface is close to a Van Hove singularity, shows a variety of weak coupling instabilities. It is a convenient model to study the interplay between antiferromagnetism and anisotropic superconductivity. We present a detailed analysis of the kinematics of electron scattering in this model. The similarities and differences between a standard renormalization group approach and previous work based on parquet summations of log (2) divergences are analyzed, with emphasis on the underlying physical processes. General properties of the phase diagram are discussed.

Journal Article↗
PubMed2000

Searching for the prototypic eye genetic network: Sine oculis is essential for eye regeneration in planarians.

We have identified a sine oculis gene in the planarian Girardia tigrina (Platyhelminthes; Turbellaria; Tricladida). The planarian sine oculis gene (Gtso) encodes a protein with a sine oculis (Six) domain and a homeodomain that shares significant sequence similarity with so proteins assigned to the Six-2 gene family. Gtso is expressed as a single transcript in both regenerating and fully developed eyes. Whole-mount in situ hybridization studies show exclusive expression in photoreceptor cells. Loss of function of Gtso by RNA interference during planarian regeneration inhibits eye regeneration completely. Gtso is also essential for maintenance of the differentiated state of photoreceptor cells. These results, combined with the previously demonstrated expression of Pax-6 in planarian eyes, suggest that the same basic gene regulatory circuit required for eye development in Drosophila and mouse is used in the prototypic eye spots of platyhelminthes and, therefore, is truly conserved during evolution.

Amino Acid Sequence↗
PubMed2000

Automated interpretation of low-energy collision-induced dissociation spectra by SeqMS, a software aid for de novo sequencing by tandem mass spectrometry.

SeqMS, a software aid for de novo sequencing by tandem mass spectrometry (MS/MS), which was initially developed for the automated interpretation of high-energy collision-induced dissociation (CID) MS/MS spectra of peptides, has been applied to the interpretation of low-energy CID and post-source decay (PSD) spectra of peptides. Based on peptide backbone fragmented ions and their related ions, which are the dominant ions observed in the latter two techniques, the types of ions and their propensities to be observed have been optimized for efficient interpretation of the spectra. In a typical example, the modified SeqMS allowed the complete sequencing of a 31-amino acid synthetic peptide, except for the isobaric amino acids (Leu or Ile, and Lys or Gln), based on only the low-energy CID-MS/MS spectrum.

Amino Acid Sequence↗