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Biomedical subjects

C Gonzalez

Publications and source records attributed to C Gonzalez.

At least 37 records · Page 2Linked to original sources
PubMed2001

The prevalence and predictive value of abnormal preoperative laboratory tests in elderly surgical patients.

UNLABELLED: Because data to determine which preoperative laboratory tests are important in elderly surgical patients are limited, we performed a prospective cohort study to evaluate the prevalence and predictive value of abnormal preoperative laboratory tests in consecutive patients > or =70 yr old who were undergoing noncardiac surgery. Patients presenting for surgery requiring only local anesthesia or monitored anesthesia care were excluded. Preoperative risk factors and laboratory test results were measured and evaluated for their association with the occurrence of predefined in-hospital postoperative adverse outcomes. In 544 patients, the prevalence of preoperative electrolytes and platelet count abnormalities (<115 x10(9)/L) was small (0.5%-5%), and abnormal creatinine (>1.5 mg/dL), hemoglobin (<10 g/dL), and glucose (>200 mg/dL) values were 12%, 10%, and 7%, respectively. Univariate predictors for adverse outcome of abnormal sodium and creatinine were not as predictive as ASA classification and surgical risk. By multivariate logistic regression, only ASA classification (>II) (odds ratio [OR], 2.55; 95% confidence interval [CI], 1.56-4.19; P < 0.001) and surgical risk (OR, 3.48; 95% CI, 2.31-5.23; P < 0.001) were significant independent predictors of postoperative adverse outcomes. The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated. IMPLICATIONS: The prevalence of abnormal preoperative electrolyte values and thrombocytopenia was small and had low predictive values. Although more prevalent, abnormal hemoglobin, creatinine, and glucose values were also not predictive of postoperative adverse outcomes. Routine preoperative testing for hemoglobin, creatinine, glucose, and electrolytes on the basis of age alone may not be indicated in geriatric patients. Rather, selective laboratory testing, as indicated by history and physical examination, which will determine patient's comorbidities and surgical risk, seems to be indicated.

Aged↗
PubMed2001

Disease knowledge and attitudes toward predictive testing and prenatal diagnosis in families with Machado-Joseph disease from the Azores Islands (Portugal).

OBJECTIVE: Machado-Joseph disease (MJD) reaches its highest prevalence world-wide in the Azores, thus constituting a public health problem in these islands. The aim of the study was thus to (1) determine the level of knowledge about the disease; (2) estimate the expected level of request for predictive testing, and (3) analyse the intentions of at-risk individuals concerning their reproductive decisions. METHODS: A questionnaire on these points was distributed to 42 affected and 36 at-risk individuals. RESULTS: As expected, the educational level of the respondents was significantly associated with the level of knowledge about the disease. The survey indicated that 83.3% of the at-risk individuals would make use of predictive test and that 77.8% would make use of prenatal diagnosis. Of the latter, 36.1% would terminate pregnancy if confronted with a positive result for the fetus. CONCLUSIONS: The level of knowledge about MJD in the Azorean families is considered to be fair. Although the actual behavior can prove to be different from the intentions put forward by at-risk individuals based solely on the results of this study we can estimate that the request for a predictive test would be quite high. The intentions expressed by at-risk individuals seem to indicate that the prenatal diagnosis will have an effect on their reproductive decisions. Results obtained certify the importance of implementing genetic testing for MJD in the Azores.

Attitude to Health↗
PubMed2001

Thyrotropin-releasing hormone receptor (TRHR) gene is associated with essential hypertension.

In essential hypertension, a polygenic and multifactorial syndrome, several genes interact with the environment to produce high blood pressure. Thyrotropin-releasing hormone (TRH) plays an important role in central cardiovascular regulation. We have described that TRH overexpression induces hypertension in a normal rat, which was reversed by TRH antisense treatment. This treatment also reduces the central TRH hyperactivity in spontaneously hypertensive rats and normalizes blood pressure. Human TRH receptor (TRHR) belongs to the G protein-coupled seven-transmembrane domain receptor superfamily. Mutations of these receptors may result in constitutive activation. As it has been demonstrated that hypertensive patients have a blunted TSH response to TRH injection, suggesting a defect in the TRHR, we postulate that the TRHR gene is involved in human hypertension. We studied 2 independent populations from different geographic regions of our country: a sample of adult subjects from a referral clinic and a population-based sample of high school students. In search of molecular variants of TRHR, we disclosed that a polymorphic TG dinucleotide repeat (STR) at -68 bp and a novel single nucleotide polymorphism, a G-->C conversion at -221 located in the promoter of the TRHR are associated with essential hypertension. As STRs detected in gene promoters are potential Z-DNA-forming sequences and seem to affect gene expression, we studied the potentially different transcriptional activity of these TRHR promoter variants and found that the S/-221C allele has a higher affinity than does the L/G-221 allele to nuclear protein factor(s). Our findings support the hypothesis that the TRHR gene participates in the etiopathogenesis of essential hypertension.

Adolescent↗
PubMed2001

The effect of vaccination with the PAV-250 strain classical swine fever (CSF) virus on the airborne transmission of CSF virus.

The airborne transmission of Classical Swine Fever (CSF) virus to susceptible pigs, as well as the effect of vaccination with the CSF virus PAV-250 strain was investigated on this mode of transmission. Experiment I: four pigs were inoculated with the ALD CSFV strain (10(4.3) 50% TCID) by the intramuscular route, and at the onset of fever, they were introduced into an enclosed chamber. At the end of the experiment surviving pigs were sedated, anesthetized and euthanatized. Experiment II: four pigs were previously vaccinated with the CSF virus PAV-250 strain, and at 14 days post-vaccination they were challenged with the CSF virus ALD strain. In both experiments, four susceptible pigs were exposed to infectious aerosols by placing them in a chamber connected by a duct to the adjacent pen containing the infected animals and were kept there for 86 hs. In Experiment I, pigs exposed to contaminated air died as a result of infection with CSF virus on days 14, 21 and 28 post-inhalation. These four pigs seroconverted from day 12 post-inhalation. CSF virus was isolated from these animals, and the fluorescent antibody test on tonsils was positive. In Experiment II, a vaccinated pig exposed to contaminated air did not seroconvert, nor was CSF virus isolated from lymphoid tissues. However, mild fluorescence in tonsil sections from these pigs was observed. In conclusion, CSF virus was shown to be transmitted by air at a distance of 1 m to susceptible pigs. Vaccination with the PAV-250 CSF virus strain protected the pigs from clinical disease under the same conditions.

Air Microbiology↗
PubMed2001

Further mapping of the Idd5.1 locus for autoimmune diabetes in NOD mice.

The Idd5 locus for autoimmune diabetes in nonobese diabetic (NOD) mice has been mapped to the proximal half of chromosome 1 and appears to include two loci, Idd5.1 and Idd5.2, Idd5.1 being a candidate homolog of the human IDDM12 locus. Using new recombinant congenic lines, we have reduced the Idd5.1 interval to 5 cM at most, between D1Mit279 and D1Mit19 (not included). This interval now excludes the Casp8 and Cflar (Flip) candidate genes. It still retains Cd28 and Ctla4 and also includes Icos (inducible costimulator). The previously reported differential expression of Ctla4, which is induced at a lower level in NOD than in B6-activated T-cells, was found independent of Idd5.1 itself because Ctla4 expression was induced at a low level in T-cells from Idd5.1-congenic mice. The Idd5.1 locus protected against both spontaneous and cyclophosphamide-induced diabetes, but it did not prevent inflammatory infiltration of the islets of Langerhans. Furthermore, diabetogenic precursor spleen cells from prediabetic NOD and Idd5.1-congenic mice were equally capable of transferring diabetes to immunodeficient NOD.scid/scid recipient mice. The Idd5.1 locus might affect a late event of disease development, subsequent to the onset of insulitis and possibly taking place in the islets of Langerhans.

Animals↗
PubMed2000

Abciximab treatment in vitro after aspirin treatment in vivo has additive effects on platelet aggregation, ATP release, and P-selectin expression.

To prevent arterial thrombosis, abciximab is administered together with aspirin. However, whether or not there are benefits to combine abciximab with aspirin is not yet well defined. Healthy volunteers were studied for the effect of aspirin + abciximab using sodium arachidonate and adenosine diphosphate (ADP) alone or in combination to induce platelet activation/aggregation. Abciximab produced complete inhibition of platelet aggregation induced with ADP but only 40% inhibition of aggregation induced by 0.75-mmol/l sodium arachidonate. Abciximab added in vitro to platelet-rich plasma (PRP) from platelets from aspirin-treated donors produced an almost complete inhibition of platelet aggregation. Aspirin, and abciximab alone, did not inhibit adenosine triphosphate (ATP) release as thoroughly as aspirin + abciximab did. Abciximab (3-5 microg/ml) produced inhibition of P-selectin expression induced with 5 (from 46.2 +/- 6.0% to 27.4 +/- 7.0%, P=0.002) and 20-micromol/l ADP (from 53.1 +/- 8.1% to 35.1 +/- 11.0%, P=0.019), but no effect was observed when 0.75-mmol/l sodium arachidonate was used (P=0.721). Aspirin diminished P-selectin expression in sodium arachidonate-stimulated platelets (from 77.7 +/- 11.8% to 40.2 +/- 3.6%, P<0.0001) in non-aspirinated and platelets from aspirin-treated donors, respectively. Abciximab (3, 4, and 5 microg/ml) added to platelets from aspirin-treated donors decreased P-selectin expression in platelets stimulated with sodium arachidonate from 40.2 +/- 8.6% to 25.6 +/- 11.5% (P=0.027), to 20.5 +/- 3.5% (P<0.0001), and to 22.5 +/- 1.8% (P<0.0001). We concluded that the antiplatelet effect of abciximab is greatly increased by aspirin.

Abciximab↗
PubMed2000

Viral gene transfer of dominant-negative Kv4 construct suppresses an O2-sensitive K+ current in chemoreceptor cells.

Hypoxia initiates the neurosecretory response of the carotid body (CB) by inhibiting one or more potassium channels in the chemoreceptor cells. Oxygen-sensitive K(+) channels were first described in rabbit CB chemoreceptor cells, in which a transient outward K(+) current was reported to be reversibly inhibited by hypoxia. Although progress has been made to characterize this current with electrophysiological and pharmacological tools, no attempts have been made to identify which Kv channel proteins are expressed in rabbit CB chemoreceptor cells and to determine their contribution to the native O(2)-sensitive K(+) current. To probe the molecular identity of this current, we have used dominant-negative constructs to block the expression of functional Kv channels of the Shaker (Kv1.xDN) or the Shal (Kv4.xDN) subfamilies, because members of these two subfamilies contribute to the transient outward K(+) currents in other preparations. Delivery of the constructs into chemoreceptor cells has been achieved with adenoviruses that enabled ecdysone-inducible expression of the dominant-negative constructs and reporter genes in polycistronic vectors. In voltage-clamp experiments, we found that, whereas adenoviral infections of chemoreceptor cells with Kv1.xDN did not modify the O(2)-sensitive K(+) current, infections with Kv4.xDN suppressed the transient outward current in a time-dependent manner, significantly depolarized the cells, and abolished the depolarization induced by hypoxia. Our work demonstrate that genes of the Shal K(+) channels underlie the transient outward, O(2)-sensitive, K(+) current of rabbit CB chemoreceptor cells and that this current contributes to the cell depolarization in response to low pO(2).

Adenoviridae↗
PubMed2000

3-year suppression of HIV viremia with indinavir, zidovudine, and lamivudine.

BACKGROUND: Antiretroviral regimens containing HIV protease inhibitors suppress viremia in HIV-infected patients, but the durability of this effect is not known. OBJECTIVE: To describe the 3-year follow-up of patients randomly assigned to receive indinavir, zidovudine, and lamivudine in an ongoing clinical trial. DESIGN: Open-label extension of a randomized, double-blind study. SETTING: Four clinical research units. PATIENTS: 33 HIV-infected, zidovudine-experienced patients with serum HIV RNA levels of at least 20,000 copies/mL and CD4 counts ranging from 50 to 400 cells/mm3. INTERVENTION: Indinavir, zidovudine, and lamivudine. MEASUREMENTS: Safety assessments, HIV RNA levels, CD4 cell counts, and genotypic analyses. RESULTS: After 3 years of follow-up, 21 of 31 contributing patients (68% [95% CI, 49% to 83%]) had serum viral load levels less than 500 copies/mL. Twenty of 31 (65% [CI, 45% to 80%]) had levels less than 50 copies/mL. The median increase in CD4 count from baseline was 230 cells/mm3 (interquartile range, 150 to 316 cells/mm3). Nephrolithiasis occurred in 12 of 33 patients (36%). CONCLUSION: A three-drug regimen of indinavir, zidovudine, and lamivudine suppressed viremia in two thirds of patients for at least 3 years.

Adult↗
PubMed2000

1H NMR structural characterization of a nonmitogenic, vasodilatory, ischemia-protector and neuromodulatory acidic fibroblast growth factor.

A shortened genetically engineered form of acidic fibroblast growth factor (aFGF), that includes amino acids 28-154 of the full-length sequence (154 residues) plus Met in substitution of Leu27, does not induce cell division even though it is recognized by the cell membrane receptor, triggers the early mitogenic events, and retains the neuromodulatory, vasoactive, and cardio- and neuroprotective properties of the native full-length molecule. Taken together, these properties make this truncated aFGF a promising compound in the treatment of a wide assortment of neurological and cardiovascular pathologies where aFGF mitogenic activity is dispensable. Differences in biological activities between the shortened aFGF and the wild-type form have been attributed to lack of stability, and to the specific amino acid sequence missing at the N-terminus. Here we show that this shortened aFGF form has a three-dimensional structure even more stable than the wild-type protein at the mitogenic assay conditions; that this structure is similar to that of the wild type except at site 1 of interaction with the cell membrane receptor; that its lack of mitogenic activity cannot be attributed to the specific missing sequence; and that the vasodilatory activity of aFGF seems impaired by alterations of the three-dimensional structure of site 2 of interaction with the cell membrane receptor.

Amino Acid Sequence↗
PubMed2000

Photocatalytic degradation of atrazine by porphyrin and phthalocyanine complexes.

This study principally focused on a new kind of photochemical reaction catalyst: porphyrin and phthalocyanine complexes. In a first step, the preparation of the catalysts was optimized. A resin has been chosen to be the support of the complexes. Efficiency of catalytic activity is performed on the degradation of a pesticide: atrazine. The best atrazine degradation occurs with 4.6% of complexes versus substrate. The role of the surface has also been shown to be important. Then, their performances were demonstrated in terms of kinetics and degradation routes, compared to a classical catalyst: titanium dioxide. This study seeks to assess the efficiency of these systems both in a mercury lamp reactor and under solar irradiation which reduces energy costs. The best atrazine degradation half-life found for the complexes is about 200 min with the iron phthalocyanine. These catalysts exhibit particular oxidation activities. Indeed, the degradation routes have been found different between the semi-conductor and the metallic complexes. These complexes are able to cleave the triazinic ring more efficiently than the titanium dioxide.

Atrazine↗
PubMed2000

Isolation and partial characterization of three DNA polymerases from Trypanosoma cruzi.

Three distinct DNA polymerase fractions (A, B and C), were isolated from Trypanosoma cruzi epimastigote forms. Fraction A is a low molecular mass enzyme corresponding to beta-like DNA polymerase of T. cruzi. Fraction B co-purified along several purification steps with fraction A, but in the last step it was clearly separated by a phosphocellulose chromatography. Fraction C was separated from fractions A and B by binding to DEAE-cellulose column, since the other two fractions were eluted in the flowthrough. This enzyme has an apparent native molecular mass of 100 kDa and showed a high preference for poly(dC)-oligo(dG) among different template-primers tested as substrate. Western-blot and biochemical analysis strongly suggest that the three DNA polymerase fractions correspond to different molecular entities. These results are in agreement with the idea that fraction C is a new DNA polymerase of T. cruzi, not described before.

Animals↗
PubMed2000

The Spanish National Reference Database for Ionizing Radiations (BANDRRI)

The Spanish National Reference Database for Ionizing Radiations (BANDRRI) is being implemented by a reasearch team in the frame of a joint project between CIEMAT (Unidad de Metrologia de Radiaciones Ionizantes and Direccion de Informatica) and the Universidad Nacional de Educacion a Distancia (UNED, Departamento de Mecanica y Departamento de Fisica de Materiales). This paper presents the main objectives of BANDRRI, its dynamic and relational data base structure, interactive Web accessibility and its main radionuclide-related contents at this moment.

Journal Article↗
PubMed2000

Simple method for alpha1-antitrypsin deficiency screening by use of dried blood spot specimens.

The use of dried blood spot (DBS) specimens in quantitative alpha1-antitrypsin (alpha1-AT) detection or genetic analysis is limited because protein levels in the samples are low and they contain components that can interfere with polymerase chain reaction amplification. A methodological adaptation was developed to overcome these drawbacks which is discussed here. The study population consisted of 200 healthy volunteers and 300 patients with chronic obstructive pulmonary disease (COPD). DBS specimens were tested for alpha1-AT concentration using a modified nephelometric assay and phenotyped with an isoelectric focusing method. Genetic diagnosis was established by deoxyribonucleic acid sequencing using a simple purification procedure to remove contaminants. The nephelometric method showed a detection limit of 0.284 mg x dL(-1), corresponding to a serum concentration of 13 mg x dL(-1). The correlation coefficient between alpha1-AT concentrations in DBS versus serum samples was R2=0.8674 (p<0.0001). All 200 healthy individuals had DBS alpha1-AT concentrations >1.9 mg x dL(-1), corresponding to 114 mg x dL(-1) in serum samples. One hundred and twenty-five COPD patients (42%) showed alpha1-AT values <1.8 mg x dL(-1). Twenty patients with the PIZ phenotype had alpha1-AT values lower than 0.64 mg x dL(-1). On the basis of genotyping, one COPD patient was classified as heterozygous (PIMM(heerlen)). Selective elution of contaminants resulted in optimal alpha(1)1-antitrypsin genotyping. Because of its sensitivity and excellent correlation with the standard method, the dried blood spot quantitative assay is a reliable tool for routine measurement of alpha1-antitrypsin.

Blood Specimen Collection↗
PubMed2000

Extramedullary plasmacytoma of the orbit.

PURPOSE: To report a case of extramedullary plasmacytoma of the orbit. METHODS: A 71-year-old patient presented with diplopia eyelid fullness and limitation of ocular motility in the left eye. Visual acuity was counting fingers, intraocular pressure 34 mmHg and fundus eye examination showed choroidal folds in the involved eye. RESULTS: CT scan showed a mass filling the superior and external left orbit without bone destruction. A biopsy was performed revealing that the tumour was composed of plasmacytoid cells positive with immunohistochemical stains for Kappa light chains and epithelial membrane antigen. Systemic work up was negative. The diagnosis of extramedullary orbital plasmacytoma was made. The patient was treated with external beam radiotherapy (40 Gy) and has remained disease free for four years (49 months). CONCLUSION: Extramedullary plasmacytomas of the orbit are extremely rare tumours. Accurate and early diagnosis is essential for the therapeutic approach. Extensive medical work up to rule out multiple myeloma or other malignant lymphoproliferative conditions involving the orbit is needed when the diagnosis of orbital extramedullary plasmacytoma is suspected because treatment and prognosis are very different.

Aged↗
PubMed2000

Effect of peritoneal fluid on whole body and segmental multiple frequency bioelectrical impedance in patients on peritoneal dialysis.

OBJECTIVE: We investigated the ability of whole body and segmental multiple frequency bioelectrical impedance (MFBIA) to detect peritoneal fluid in peritoneal dialysis patients. DESIGN: Prospective study. SETTING: Teaching hospital renal unit. SUBJECTS: Patients on regular peritoneal dialysis. INTERVENTIONS: Whole body and segmental MFBIA measurements before and after drainage of peritoneal fluid. RESULTS: Changes estimated by MFBIA in total body water (-0.4 (0.8) litres) and extracellular water (-0.3 (0.3) litres) were much lower than the actual changes (2.0 (0.4) litres), P<0.0001. Derived resistances Recf and Ricf increased significantly for the trunk but not for total body measurements and changes did not correlate with volumes of fluid drained. CONCLUSIONS: MFBIA is limited in its ability to detect intraperitoneal fluid, using both whole body and segmental techniques.

Adult↗