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Biomedical subjects

L Rubio

Publications and source records attributed to L Rubio.

At least 37 records · Page 2Linked to original sources
PubMed2000

Morphometric study of tumor angiogenesis as a new prognostic factor in nasopharyngeal carcinoma patients.

The aim of this study was to determine the possible prognostic significance of tumor angiogenesis (TA) in nasopharyngeal carcinoma (NPC) patients. Fifty-five NPC patients were evaluated in relation to survival. Endothelial cells were immunohistochemically stained with anti-von Willebrand factor (F-VIII), CD-31 and CD-34 antibodies, and microvessels counted in the most active areas of tumor neovascularization or hotspotsusing both a manual and an automatic method. Overall survival analysis calculated by the Kaplan Meiertest revealed that both methods were correlated with a statistical significance between intratumoral microvessel density (IMD) and overall survival, using either manual (p=0.0141) or automatic counting (p=0.0117). Other angiogenic parameters studied were perimeter, roundness and accumulative area of the microvessels using a morphometric analyzer. Moreover, our results show that cases with high IMD demonstrated a prognostic significance in relation to the accumulative area (p=0.0072).

Adult↗
PubMed2000

A new procedure to differentiate citrus tristeza virus isolates by hybridisation with digoxigenin-labelled cDNA probes.

A non-isotopic hybridisation procedure was developed to differentiate isolates of citrus tristeza virus (CTV) using digoxigenin (DIG)-labelled cDNA probes and different kinds of target RNA. Hybridisation of DIG-probes with purified double-stranded RNA (dsRNA) or concentrated total RNA extracts spotted on nylon membranes allowed detection of CTV nucleic acid equivalent to as little as 0.1-1 mg infected tissue, when the reaction was developed with a chemiluminiscent substrate. This sensitivity was similar to or slightly better than that obtained by hybridisation with a 32P-labelled probe. CTV was also detectable by hybridisation of DIG-probes with tissue prints from freshly cut young citrus shoots. Hybridisation of tissue prints with DIG-probes under stringent conditions (60 degrees C and 50% formamide) could differentiate CTV isolates in citrus, whether grown in the greenhouse or in the field. This rapid and sensitive procedure can easily be applied to many samples, even under field conditions, and opens the way to monitoring spatio-temporal movement of specific CTV strains (or groups of strains) in epidemiological studies.

Antibodies, Monoclonal↗
PubMed2000

Inducible myocardial ischaemia in asymptomatic Type 2 diabetic patients.

BACKGROUND: to define the prevalence of inducible myocardial ischaemia in asymptomatic Type 2 diabetic patients and its relation to urinary albumin excretion rate (AER). METHODS: 98 Type 2 diabetic patients aged 56+/-7 years, and 20 non-diabetic volunteers were recruited. Dypiridamole plus exercise thallium-201 myocardial single photon emission computed tomography (SPECT) was performed in all participants. Exclusion criteria were: age <30 or >70 years, evidence of cardiovascular disease, anomalous ECG, autonomic neuropathy or serum creatinine level >177 micromol/l. RESULTS: 36 out of 98 diabetic patients (37%) showed abnormal thallium SPECT (considered as inducible myocardial ischaemia), versus one out of 20 (5%) in control group (odds ratio 7.3 (95% CI 1.1-50.5), P<0.005). Among diabetic patients, prevalence of inducible ischaemia was greater in those with higher urinary AER (AER <30:30-300:> 300 mg/24 h: 26: 53: 88%, and greater in the normoalbuminuric group compared to the control group (26 vs. 5%; P<0.05). An AER >30 mg/24 h was the only independent factor associated with inducible myocardial ischaemia in the multivariate analysis (P=0.009). CONCLUSIONS: raised urinary AER in asymptomatic diabetic patients is a risk factor for present myocardial ischaemia demonstrated by thallium dypiridamole tomography. The prevalence of inducible myocardial ischaemia in asymptomatic diabetic patients without known coronary disease is much higher than in non-diabetic population.

Adult↗
PubMed2000

Population structure and genetic diversity within California Citrus tristeza virus (CTV) isolates.

The Closterovirus, Citrus tristeza virus (CTV) is an aphid-borne RNA virus that is the causal agent of important worldwide economic losses in citrus. Biological and molecular variation has been observed for many CTV isolates. In this work we detected and analyzed sequence variants (haplotypes) within individual CTV isolates. We studied the population structure of five California CTV isolates by single strand conformation polymorphism (SSCP) analysis of four CTV genomic regions. Also, we estimated the genetic diversity within and between isolates by analysis of haplotype nucleotide sequences. Most CTV isolates were composed of a population of genetically related variants (haplotypes), one being predominant. However in one case, we found a high nucleotide divergence between haplotypes of the same isolate. Comparison of these haplotypes with those from other isolates suggests that some CTV isolates could have arisen as result of a mixed infection of two divergent isolates.

Base Sequence↗
PubMed2000

Asynchronous accumulation of lettuce infectious yellows virus RNAs 1 and 2 and identification of an RNA 1 trans enhancer of RNA 2 accumulation.

Time course and mutational analyses were used to examine the accumulation in protoplasts of progeny RNAs of the bipartite Crinivirus, Lettuce infectious yellow virus (LIYV; family Closteroviridae). Hybridization analyses showed that simultaneous inoculation of LIYV RNAs 1 and 2 resulted in asynchronous accumulation of progeny LIYV RNAs. LIYV RNA 1 progeny genomic and subgenomic RNAs could be detected in protoplasts as early as 12 h postinoculation (p.i.) and accumulated to high levels by 24 h p.i. The LIYV RNA 1 open reading frame 2 (ORF 2) subgenomic RNA was the most abundant of all LIYV RNAs detected. In contrast, RNA 2 progeny were not readily detected until ca. 36 h p.i. Mutational analyses showed that in-frame stop codons introduced into five of seven RNA 2 ORFs did not affect accumulation of progeny LIYV RNA 1 or RNA 2, confirming that RNA 2 does not encode proteins necessary for LIYV RNA replication. Mutational analyses also supported that LIYV RNA 1 encodes proteins necessary for replication of LIYV RNAs 1 and 2. A mutation introduced into the LIYV RNA 1 region encoding the overlapping ORF 1B and ORF 2 was lethal. However, mutations introduced into only LIYV RNA 1 ORF 2 resulted in accumulation of progeny RNA 1 near or equal to wild-type RNA 1. In contrast, the RNA 1 ORF 2 mutants did not efficiently support the trans accumulation of LIYV RNA 2. Three distinct RNA 1 ORF 2 mutants were analyzed and all exhibited a similar phenotype for progeny LIYV RNA accumulation. These data suggest that the LIYV RNA 1 ORF 2 encodes a trans enhancer for RNA 2 accumulation.

Base Sequence↗
PubMed1999

The haplotype distribution of two genes of citrus tristeza virus is altered after host change or aphid transmission.

Genetic variability of citrus tristeza virus (CTV) was studied using the haplotypes detected by single-strand conformation polymorphism (SSCP) analysis of genes p18 and p20 in six virus populations of two origins. The Spanish group included a CTV isolate and subisolates obtained by graft-transmission to different host species. The other included two subisolates aphid-transmitted from a single Japanese isolate. The homozygosity observed for gene p20 was always significantly higher than that expected under neutral evolution, whereas only three populations showed high homozygosity for p18, suggesting stronger host constraints for p20 than for p18. Sequential transmissions of a Spanish isolate to new host species increased the difference between its population and that of the successive subisolates for gene p18, as estimated by the F statistic. Analysis of molecular variance indicated that variation between both groups of populations was not statistically significant, whereas variations between populations of the same group or within populations were significant for both genes studied. Our data indicate that selection affects the haplotype distribution and that adaptation to a new host can be as important or more as the geographical origin. Variation of the CTV populations after host change or aphid transmission may explain in part the wide biological variability observed among CTV isolates.

Analysis of Variance↗
PubMed1999

The complete genome sequence of the major component of a mild citrus tristeza virus isolate.

The genome of the Spanish mild isolate T385 of citrus tristeza virus (CTV) was completely sequenced and compared with the genomes of the severe isolates T36 (Florida), VT (Israel) and SY568 (California). The genome of T385 was 19,259 nt in length, 37 nt shorter than the genome of T36, and 33 and 10 nt longer than those of VT and SY568, respectively, but their organization was identical. T385 had mean nucleotide identities of 81.3, 89.3 and 94% with T36, VT and SY568, respectively. The 3' UTR had over 97% identity in all isolates, whereas the 5' UTR of T385 had 67% identity with VT, 66.3% with SY568 and only 42.5% with T36. In the coding regions, the nucleotide differences between T385 and VT were evenly distributed along the genome (around 90% identity); this was not observed between T385 and the other isolates. T385 and T36 had nucleotide identities around 90% in the eight 3'-terminal ORFs of the genome, but only 72.3% in ORF 1a, a divergence pattern similar to that reported previously for T36 and VT. T385 and SY568 had nucleotide identities close to 90% in the 5'- and 3'-terminal regions of the genome, whereas the central region had over 99% identity. Our data suggest that the central region in the SY568 genome results from RNA recombination between two CTV genomes, one of which was almost identical to T385.

Base Sequence↗
PubMed1999

Lettuce infectious yellows virus: in vitro acquisition analysis using partially purified virions and the whitefly Bemisia tabaci.

Virions of lettuce infectious yellows virus (LIYV; genus Crinivirus) were purified from LIYV-infected plants and their protein composition was analysed by SDS-PAGE and immunoblotting. Virion preparations contained the major capsid protein (CP), but the minor capsid protein (CPm), p59 and the HSP70 homologue were also identified by immunoblot analysis. Immunogold labelling analysis showed that CP constituted the majority of the LIYV virion capsid, but CPm was also part of the capsid and localized to one end of the virion, similar to the polar morphology seen for viruses in the genus Closterovirus. p59 and the HSP70 homologue were not detected on virions by immunogold labelling, but were always detected in virion preparations by immunoblot analysis. Purified LIYV virions were used for in vitro acquisition analysis with Bemisia tabaci whiteflies and were efficiently transmitted to plants. Infectivity neutralization analyses were done using antisera to the LIYV-encoded CP, CPm, p59 and HSP70 homologue. Only antiserum to the CPm effectively neutralized LIYV transmission by B. tabaci. These data suggest that the LIYV-B. tabaci transmission determinants are associated with purified virions, and that the LIYV virion structural protein CPm is involved in transmission by B. tobaci.

Animals↗
PubMed1998

[Obtaining myo-cardial perfusion images synchronized with the ECG (gated-SPEC) after injecting MIBI during exertion: comparative study with echocardiography in 95 patients for the assessment of left ventricular function].

Technical innovation has recently resulted in the routine use of gated-SPECT in myocardial perfusion imaging. In the present work we compare estimates of left ventricular function (LV cavity) by gated-SPECT with those of conventional echocardiography in a group of 95 ischemic patients, 49 of whom had previous myocardial infarction. Kappa analysis showed correlation coefficients of 0.67 for global function in the whole group and of 0.68 in patients with MI, as well as of 0.56 in the anterior wall, and 0.55 in the inferior wall. With these data, we believe that the technique is useful and it adds to the conventional perfusion SPECT imaging. Also, it is conveniently validated against echocardiography in our hands.

Adult↗
PubMed1992

[Acute early rejection in renal transplantation].

The incidence of early acute rejection (first two months after surgery) was evaluated in a group of 150 kidney transplants, receptors, who were followed for more than three months. Ninety nine were transplanted with kidney from a cadaver donor and 51 with living donor. One hundred forty two patients were treated with triple immunosuppression therapy (cyclosporine, prednisone and azathioprine). The incidence of early acute rejection was significantly higher in cadaver kidney receptors (34% vs 19.6%, p = 0.04. Fisher exact test). However, early rejection did not have demonstrable influence in graft or patient survival or in the follow-up graft function. Graft and patient survival were not affected by the severity of the rejection episode.

Acute Disease↗
PubMed1992

Prajmalium, an antiarrhythmic with positive inotropic effect: mechanism of action in rabbit single cardiomyocytes.

The propyl derivative of ajmaline, N-n-propylajamaline (prajmalium), is an antiarrhythmic compound that lacks the commonly reported negative inotropic effects of all others under clinical use. The present study was undertaken to establish and understand its effects at the cellular level in mammalian preparations. Electrical and mechanical activities were recorded from right ventricular strips and Na and L-type Ca currents (INa and ICaL, respectively) were recorded with the whole-cell patch-clamp technique in right ventricular myocytes freshly dissociated from rabbit hearts. Prajmalium decreased the maximal rate of depolarization of the action potential in a dose-dependent manner with an EC50 of 3 microM. This effect was use and frequency dependent. Action potential duration was increased by 1 microM prajamalium but decreased on applying higher concentrations. The force of contraction was slightly (15%) increased at 0.1 microM, not affected at all at 1 microM and depressed by 30% at 20 microM. In single cardiomyocytes maintained at negative holding potentials, INa was slightly depressed by prajmalium at 10 nM and reduced by 75% at 10 microM. ICaL was increased by 30 and 20% on applying prajmalium at 1 and 10 microM, respectively; on the other hand, ICaL was reduced by these two concentrations of prajmalium at less negative holding potentials. A higher prajmalium concentration (100 microM) decreased ICaL at all holding potentials studies and this effect was enhanced with depolarization. The increase in ICaL induced by prajmalium (1 microM) was also observed after ICaL had been fully beta-adrenergic and P2-purinergic stimulated by isoproterenol (1 microM) in the presence of IBMX (100 microM) and ATP (10 microM). It is concluded that prajmalium is able to increase ICaL in rabbit ventricular cells in a voltage-dependent manner, an effect that could account in part for the observed lack of negative inotropism of this antiarrhythmic in clinics.

Action Potentials↗
PubMed1992

[Primary angiosarcoma of the heart. A report of a new case and a review of the literature].

The case is presented of a primitive heart angiosarcoma (PHA) in a 53-year-old woman who developed repeated episodes of hemopericardium with cardiac tamponade. A literature review is performed. PHA is the most frequent primitive cardiac tumor. It is usually localized in the right striatum and is accompanied by effusion of pericardium and right heart failure. The diagnosis is usually made late and bidimensional echography is of great value. Treatment is surgical, if possible. Chemotherapy protocols are being used but with obscure prognosis.

Cardiac Tamponade↗
PubMed1991

[Usefulness of ketoconazole combined with cyclosporin in renal transplantation].

To reduce the cost of treatment in renal transplant patients, ketoconazole, an inhibitor of the cytochrome P-450 enzyme system, was added to their triple immunosuppressive treatment (prednisone, azathioprine and cyclosporine). Thirty seven patients were included; they received 100-200 mg/day of ketoconazole and the amount of cyclosporine given was adjusted to keep its whole blood concentration within a therapeutic range. The dose of cyclosporine was decreased 70.4% by the first month of combined treatment and 76% by the ninth month. The benefit obtained with this reduction allowed the use of cyclosporine to be extended to all the patients and to administer it permanently. In 3 patients the increase in the serum hepatic enzymes made us stop ketoconazole. In order to detect hepatotoxicity early, periodic monitoring of liver function tests is mandatory.

Adolescent↗
PubMed1990

Relationship between survival and binding of plant lectins during small intestinal passage and their effectiveness as growth factors.

The effects on the small intestine and the growth of rats of six pure plant lectins: PHA (Phaseolus vulgaris); SBL (Glycine maxima); SNA-I and SNA-II (Sambucus nigra); GNA (Galanthus nivalis) and VFL (Vicia faba), covering most sugar specificities found in nature, were studied in vivo. Variable amounts, 25% (VFL) to 100% (PHA, GNA) of the lectins administered intragastrically, remained in immunochemically intact form in the small intestine after 1 h. All lectins, except GNA, showed binding to the brush border on first exposure, although this was slight with VFL. Thus, binding to the gut wall was not obligatory for resistance to proteolysis. Exposure of rats to lectins, except VFL, for 10 days, retarded their growth but induced hyperplastic growth of their small intestine. The two activities were directly related. PHA and SNA-II, whose intestinal binding and endocytosis was appreciable after 10 days of feeding the rats with diets containing these lectins and similar to that found on acute (1 h) exposure, were powerful growth factors for the small intestine. GNA, which did not bind at the start but was reactive after 10 days, and SNA-I, which behaved in the opposite way, induced changes in receptor expression in the gut. As they were bound to the brush border transiently, they were less effective growth factors. VFL was not bound or endocytosed, was non-toxic and did not promote gut growth.

Animals↗