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R Santos

Publications and source records attributed to R Santos.

At least 19 recordsLinked to original sources
PubMed2006

Hemodynamic, autonomic and neurohormonal behaviour of familial amyloidotic polyneuropathy and neurally mediated syncope patients during supine and orthostatic stress.

Orthostatic intolerance (OI) syndromes are frequent and share symptoms like dizziness and orthostatic syncope. Their pathophysiology however seems to be different. The aim of our work was to evaluate autonomic and hemodynamic behaviour in patients with familial amyloidotic polyneuropathy and neurally mediated syncope in supine position and after acute orthostatic passive stress. We studied 12 patients with autonomic failure (group A), 12 patients with neurally mediated syncope (group B) and 16 aged matched normal controls (group C), in supine position and during the first 10 min of head-up tilt test (HUTT). Beat-by-beat blood pressure and heart rate were continuously monitored and digitised at 500 Hz. The baroreceptor alfa-index gain (vagal reflex-BRG), high frequency of RR variability (HFRR, vagal tonus) and low frequency of systolic arterial pressure variability (LFSAP, sympathetic tone) were calculated. Catecholamines, plasma brain (BNP) and atrial natriuretic (ANP) peptides were also measured. Hemodynamic data were derived and calculated by the non-invasive modelflow method. During supine position, cardiac output (CO) and stroke volume (SV) were similar in all groups. Mean arterial pressure (MAP) and BNP were higher in group A. Noradrenaline (NOR), BRG, HFRR and LFSAP were extremely low in this group. BRG and adrenaline (ADR) were higher in group B than in controls. Within the first 10 min of HUTT, there was a huge drop of CO, SV and MAP in group A, maintenance of very low levels of neurohormones and lack of autonomic function. HR, LFSAP and ADR had a higher rise at HUTT in group B compared with controls (p<0.01) but a significant decrease of BRG was noted (p<0.05). ANP or BNP did not change with tilt in any group. Different orthostatic intolerance syndromes may show important hormonal, autonomic and hemodynamic differences during supine rest and enhanced after passive orthostatism.

Adult↗
PubMed2005

Hepatocytes cultured in alginate microspheres: an optimized technique to study enzyme induction.

An important application of hepatocyte cultures is identification of drugs acting as inducers of biotransformation enzymes that alter metabolic clearance of other therapeutic agents. In the present study we optimized an in vitro system with hepatocytes cultured in alginate microspheres that allow studies of enzyme induction with excellent sensitivity. Induction factors obtained with standard inducers, such as 3-methylcholanthrene or phenobarbital, were higher compared to those with conventional hepatocyte co-cultures on collagen coated dishes. This is illustrated by activities of 7-ethoxyresorufin-O-deethylase (EROD) after incubation with 5 microM 3-methylcholanthrene (3-MC), a standard inducer for cytochrome P4501A1 and 1A2. Mean activities for solvent controls and 3-MC exposed cells were 2.99 and 449 pmol/min/mg protein (induction factor: 150) for hepatocytes cultured in microspheres compared to 2.72 and 80.6 pmol/min/mg (induction factor: 29.6) for hepatocytes on collagen coated dishes. To compare these in vitro data to the in vivo situation male Sprague Dawley rats, the same strain that was used also for the in vitro studies, were exposed to 3-MC in vivo using a protocol that guarantees maximal induction. Activities were 29.2 and 1656 pmol/min/mg in liver homogenate of solvent and 3-MC treated animals (induction factor: 56.7). Thus, the absolute activities of 3-MC exposed hepatocytes in microspheres are lower compared to the in vivo situation. However, the induction factor in vitro was even higher compared to the in vivo situation (150-fold versus 56.7-fold). A similar scenario was observed using phenobarbital (0.75 mM) for induction of CYP2B and 3A isoenzymes: induction factors for testosterone hydroxylation in position 16beta were 127.5- and 50.4-fold for hepatocytes in microspheres and conventionally cultured hepatocytes, respectively. The new in vitro system with hepatocytes embedded in solid alginate microspheres offers several technical advantages: (i) the solid alginate microspheres can be liquefied within 60s, allowing a fast and complete harvest of hepatocytes; (ii) alginate capsules are stable allowing transport and mechanical stress; (iii) high numbers of hepatocytes can be encapsulated in short periods; (iv) defined cell numbers between 600 hepatocytes, the approximate number of cells in one capsule, and 18 x 10(6) hepatocytes, the number of hepatocytes in 6 ml alginate, can be transferred to a culture dish or flask. Thus, encapsulated hepatocytes allow a flexible organization of experiments with respect to cell number. In conclusion, we optimized a technique for encapsulation of hepatocytes in alginate microspheres that allows identification of enzyme induction with an improved sensitivity compared to existing systems.

Alginates↗
PubMed2005

Echinoderm adhesive secretions: from experimental characterization to biotechnological applications.

Adhesion is a way of life in echinoderms. Indeed, all the species belonging to this phylum use adhesive secretions extensively for various vital functions. According to the species or to the developmental stage considered, different adhesive systems may be recognized. (1) The tube feet or podia are organs involved in attachment to the substratum, locomotion, feeding or burrowing. Their temporary adhesion relies on a duo-gland adhesive system resorting to both adhesive and de-adhesive secretions. (2) The larval adhesive organs allow temporary attachment of larvae during settlement and strong fixation during metamorphosis. (3) The Cuvierian tubules are sticky defence organs occurring in some holothuroid species. Their efficacy is based on the instantaneous release of a quick-setting adhesive. All these systems rely on different types of adhesion and therefore differ in the way they operate, in their structure and in the composition of their adhesive. In addition to fundamental interests in echinoderm bioadhesives, a substantial impetus behind understanding these adhesives are the potential technological applications that can be derived from their knowledge. These applications cover two broad fields of applied research: design of water-resistant adhesives and development of new antifouling strategies. In this context, echinoderm adhesives could offer novel features or performance characteristics for biotechnological applications. For example, the rapidly attaching adhesive of Cuvierian tubules, the releasable adhesive of tube feet or the powerful adhesive of asteroid larvae could each be useful to address particular bioadhesion problems.

Adhesiveness↗
PubMed2005

[Bulbourethral sling. The experience of our service].

OBJECTIVES: The authors present the clinic results obtained with the bulbourethral sling application with pubic bone anchorage (Invance) in patients with stress urinary incontinence. MATERIAL AND METHODS: From July to December 2003, 10 slings were implanted in men between the 60's and the 83 years old (average 72.6 years), whose incontinence appeared after prostatic surgery (retro pubic radical prostatectomy, perineal radical prostatectomy, radical cystoprostatectomy with Camey II neobladder, transurethral resection, transvesical prostate adenomectomy). RESULTS: After 9 months follow-up (3 to 7 months), 8 patients (80%) are continent (without need of using any pad) and 2 (20%) show minimum leakage with effort (need of 1 to 2 daily pads). All are satisfied with the surgery result. Two patients referred perineal pain, which was solved with Paracetamol. There was no case of perineal haematoma, infection, rejection or urethral erosion. CONCLUSION: The bulbourethral sling with bone anchorage is a rather invasive procedure, of easy technical execution, with high continence rates and associated to low morbidity. Although the presented results been an incentive to the technique prolongation, it would be necessary a higher tracking: and higher global experience in order that this sling affirm and transform itself in an alternative to the artificial sphincter in selected cases.

Aged↗
PubMed2005

Influence of antipyretic drugs on the labeling of blood elements with technetium-99m.

Acetaminophen (AAP), acetylsalicylic acid (ASA) and dipyrone (DIP) are antipyretic and analgesics drugs that have wide use in health sciences. Some drugs can modify the labeling of blood elements with technetium-99m (99mTc). This work has evaluated the effect of AAP, ASA and DIP on the labeling of the blood elements with 99mTc. Blood was incubated with different concentrations of the drugs before the 99mTc-labeled process. Plasma (P), blood cells (BC), insoluble (IF-P, IF-BC) and soluble (SF-P, SF-BC) fractions were separated and percentage of radioactivity (%ATI) in each fraction was determined. Data have shown that the antipyretic drugs used in this study did not significantly modify the fixation of 99mTc on the blood elements when the experiments were carried out with the doses usually used in human beings. Although the experiments were carried out with rats, it is possible to suggest that AAP, ASA or DIP should not interfere with the procedures in nuclear medicine involving the labeling of blood elements with 99mTc.

Acetaminophen↗
PubMed2005

Detection and identification of mycobacteria in the Lisbon water distribution system.

Mycobacteria have emerged as a major cause of opportunistic infections. Until the present, only a few studies have characterized mycobacteria present in the water distribution system of urban areas. In this study, we characterize these microorganisms in the Lisbon water distribution system. Our results indicate a high rate of positivities (90.5%) with mainly saprophytic mycobacteria. Around 63% of these results belong to strains of Mycobacterium gordonae indicating a generalized proliferation of this species in the Lisbon water distribution system. A total of 21.05% of the isolates are from M. kansasii, M. intracellulare and M. chelonae.

Cities↗
PubMed2004

[Combined Scanners (PET/CT, SPECT/CT) Versus Multimodality Imaging with Separated Systems].

With increasing use of combined PET/CT scanners in the last few years, multimodality imaging (Nuclear Medicine/Radiology) found its way into clinical routine diagnostics. In this overview, necessary components for multimodality imaging, strategies for image analysis and image presentation, and diagnostic goals of combined imaging are demonstrated and discussed. A special focus is on the question, whether combined scanners can be replaced by a software approach with separated modalities. Advantages and limitations of multimodality imaging with combined or separated scanners are shown.

Computers↗
PubMed2003

Lymphadenitis caused by Aerococcus urinae infection.

Aerococcus urinae is rarely reported as a human pathogen. The pathogenesis of this gram-positive coccus is not fully understood. It has been identified as a cause of urinary tract infections but may be associated with severe infections such as endocarditis and septicaemia. This paper presents a case of lymphadenitis caused by A. urinae.

Aged↗
PubMed2002

Study of the biodistribution of the amantadine labelled with technetium-99m in Wistar female rats.

Amantadine (AMA) has been described as dopamine stimulant and norepineprhine release, capable to block the N-methyl-D aspartate (NMDA) glutamatergic and nicotinic receptors, enhancing the sexual behavior of the male rats and inducing hypersexuality in humans. The use of technetium-99m (99mTc) can be justified for its physical and chemical properties. The aim of this study was to label and evaluate the bioavailability of the AMA labelled with 99mTc (99mTc-AMA) in Wistar female rats. The solution of 99mTc-AMA was administered by intraperitoneal way and the animals were sacrificed in CO2 chamber 10 min after the administration of the radiotracer. Various organs were removed, weighted, their radioactivity was determined using an auto-gamma counter and the results were expressed as the percentage of the injected activity per gram of tissue (%ATI/g). In the control group only Na99mTcO4 was administered. The analysis of results shows that the highest uptakes 99mTc-AMA treated group were: ovary (7.11 +/- 1.43), spleen (3.54 +/- 1.05), thyroid (2.67 +/- 0.15), stomach (1.56 +/- 1.10), duodenum (0.87 +/- 0.52), muscular tissue (0.57 +/- 0.06), liver (0.52 +/- 0.25), and at control group: thyroid (16.45 +/- 2.57), ovary (1.28 +/- 0.12), liver (1.10 +/- 0.04), spleen (0.57 +/- 0.07) and muscular tissue (0.26 +/- 0.03). The results obtained suggest that 99mTc-AMA may be used to study the bioavailability of amantadine and evaluate its effect in sexual behavior in female rats.

Amantadine↗
PubMed2001

Initial sequencing and analysis of the human genome.

The human genome holds an extraordinary trove of information about human development, physiology, medicine and evolution. Here we report the results of an international collaboration to produce and make freely available a draft sequence of the human genome. We also present an initial analysis of the data, describing some of the insights that can be gleaned from the sequence.

Animals↗
PubMed2001

Cervical cancer screening in Porto Alegre, Brazil: alternative methods for detecting cancer precursors in a developing country.

OBJECTIVE: This study was conducted to test the performance characteristics of cervical cancer screening by visual inspection of the cervix with acetic acid and iodine solution. METHODS: A total of 100 women were screened for cervical cancer by Pap smear and naked eye inspection of the cervix after application of acetic acid and iodine solution. RESULTS: Comparing visual inspection to the Pap test, a sensitivity of 85.7%, specificity of 78.5%, and concordance of 79% (p < .0011) was established. Comparing the Pap test with colposcopy, the corresponding figures were 42.9%, 92.3%, and 66.6% (p < .077), respectively. Visual inspection compared to colposcopy showed corresponding figures of 100%, 7.7%, and 55.5% (p = .48), respectively. Colposcopy and biopsy had an agreement of 100%. CONCLUSIONS: Visual inspection with acetic acid and iodine solution proved to be a reasonable method of screening for cervical cancer precursors.

Journal Article↗
PubMed2001

Primary renal artery stenting: characteristics and outcomes after 363 procedures.

BACKGROUND: Stenting improves the acute results of percutaneous balloon angioplasty for atherosclerotic renal artery stenosis. Predictors of benefit and angiographic restenosis are not well understood. We describe the technical and clinical success of renal artery stenting in a large consecutive series of patients with hypertension or renal insufficiency. We identify clinical, procedural, and anatomic factors that might influence outcome, restenosis, and survival. METHODS: Primary renal artery stenting was performed in 300 consecutive patients who underwent 363 stent procedures in 358 arteries. Angiograms were analyzed quantitatively. Clinical and angiographic follow-up data are available after a median of 16.0 months. RESULTS: At baseline, 87% of patients had hypertension, and 37% had chronic renal insufficiency. The mean age was 70 years (interquartile range 63.1-74.6) years. The stenosis was unilateral in 49% and bilateral in 48% and involved a solitary functioning kidney in 3.6%. The stenting procedure was successful in all attempts. There were no procedural deaths or emergency renal surgical procedures. Postprocedure azotemia was seen in 45 of 363 (12%) procedures but persisted in only 6 patients (2%), all of whom had baseline renal insufficiency. Systolic and diastolic blood pressures were significantly reduced (systolic blood pressure from 164.0 +/- 28.7 to 142.4 +/- 19.1 mm Hg, P <.001). At follow-up, 70% of patients had improved blood pressure control regardless of renal function. In patients with baseline renal insufficiency, 19% had improvement in serum creatinine levels at follow-up, 54% had stabilization, and 27% had deterioration. Follow-up mortality was 10% and was predicted by baseline creatinine levels (odds ratio 1.72 for each 1 mg/dL creatinine increment, 95% confidence interval 1.13-2.49) and extent of coronary artery disease (odds ratio 1.66 for each diseased coronary artery, 95% confidence interval 1.03-2.67). Angiographic restenosis was found in 21% of 102 patients overall and was less common (12%) in arteries with a reference caliber >4.5 mm (P <.01 vs caliber <4.5 mm). Neither poststenotic dilation nor severity of angiographic stenosis predicted clinical outcome. CONCLUSIONS: Primary renal artery stenting can be performed safely with nearly uniform technical success. The majority of patients with hypertension or renal insufficiency derive benefit. Follow-up mortality is 5-fold higher in patients with baseline renal insufficiency. Clinical and angiographic features did not predict blood pressure or renal functional outcome. Restenosis is more common in renal arteries with a reference caliber less than 4.5 mm.

Aged↗
PubMed2001

Oxidative burst in alfalfa-Sinorhizobium meliloti symbiotic interaction.

Reactive oxygen species are produced as an early event in plant defense response against avirulent pathogens. We show here that alfalfa responds to infection with Sinorhizobium meliloti by production of superoxide and hydrogen peroxide. This similarity in the early response to infection by pathogenic and symbiotic bacteria addresses the question of which mechanism rhizobia use to counteract the plant defense response.

Hydrogen Peroxide↗
PubMed2001

Essential role of superoxide dismutase on the pathogenicity of Erwinia chrysanthemi strain 3937.

The sodA gene from Erwinia chrysanthemi strain 3937 was cloned by functional complementation of an Escherichia coli sodA sodB mutant and sequenced. We identified a 639-bp open reading frame, which encodes a protein that is 85% identical to the E. coli manganese-containing superoxide dismutase MnSOD. Promoter elements of this gene were identified by transcriptional mapping experiments. We constructed an E. chrysanthemi deltasodA mutant by reverse genetics. The deltasodA mutation resulted in the absence of a cytoplasmic SOD, which displays the same characteristics as those of MnSOD. The deltasodA mutant was more sensitive to paraquat than the wild-type strain. This mutant could macerate potato tubers, similar to the wild-type strain. In contrast, when inoculated on African violets, the mutant produced, at most, only small necrotic lesions. If the inoculum was supplemented with the superoxide anion-scavenging metalloporphyrin MnTMPyP or purified SOD and catalase, the deltasodA mutant was able to macerate the inoculated zone. Generation of superoxide anion by African violet leaves inoculated with E. chrysanthemi was demonstrated with nitroblue tetrazolium as an indicator. Therefore, at the onset of infection, E. chrysanthemi cells encounter an oxidative environment and require active protective systems against oxidative damages such as MnSOD to overcome these types of conditions.

Amino Acid Sequence↗
PubMed2001

Mutational analysis of the repeated open reading frames, ORFs 63 and 70 and ORFs 64 and 69, of varicella-zoster virus.

Varicella-zoster virus (VZV) open reading frame 63 (ORF63), located between nucleotides 110581 and 111417 in the internal repeat region, encodes a nuclear phosphoprotein which is homologous to herpes simplex virus type 1 (HSV-1) ICP22 and is duplicated in the terminal repeat region as ORF70 (nucleotides 118480 to 119316). We evaluated the role of ORFs 63 and 70 in VZV replication, using recombinant VZV cosmids and PCR-based mutagenesis to make single and dual deletions of these ORFs. VZV was recovered within 8 to 10 days when cosmids with single deletions were transfected into melanoma cells along with the three intact VZV cosmids. In contrast, VZV was not detected in transfections carried out with a dual deletion cosmid. Infectious virus was recovered when ORF63 was cloned into a nonnative AvrII site in this cosmid, confirming that failure to generate virus was due to the dual ORF63/70 deletion and that replication required at least one gene copy. This requirement may be related to our observation that ORF63 interacts directly with ORF62, the major immediate-early transactivating protein of VZV. ORF64 is located within the inverted repeat region between nucleotides 111565 and 112107; it has some homology to the HSV-1 Us10 gene and is duplicated as ORF69 (nucleotides 117790 to 118332). ORF64 and ORF69 were deleted individually or simultaneously using the VZV cosmid system. Single deletions of ORF64 or ORF69 yielded viral plaques with the same kinetics and morphology as viruses generated with the parental cosmids. The dual deletion of ORF64 and ORF69 was associated with an abnormal plaque phenotype characterized by very large, multinucleated syncytia. Finally, all of the deletion mutants that yielded recombinants retained infectivity for human T cells in vitro and replicated efficiently in human skin in the SCIDhu mouse model of VZV pathogenesis.

Animals↗
PubMed2001

[Deciding about pacing mode in sinus node dysfunction: should carotid sinus massage be performed and in which circumstances?].

OBJECTIVE: To state the incidence of carotid sinus syndrome (CSS) with atrioventricular node manifestation in patients with sinus node dysfunction (SND) and indication for a definitive pacemaker (PM), we propose a new protocol between atrial pacing AAI and double chamber DDD. POPULATION AND METHODS: 69 patients (PTS) (male 71%), median age 65 +/- 10 years, with SND (normal PQ and no intraventricular conduction defect), that had a PM implant following the protocol that included carotid sinus massage for the pacing decision, were followed prospectively between December 1995 and November 1999. During the protocol we implanted DDD PM in PTS with Wenckebach less than 130 or Wenckebach equal/over 130 and CSS. At least, in PTS with Wenckebach equal/over 130 and no CSS we implanted AAI PM. The follow-up was between 4 months and 4 years, with clinical evaluation in the first and fourth months and then half yearly, with carotid sinus massage in the first evaluation. RESULTS: About 1/4 of the 69 patients followed had SND without carotid sinus syndrome, or atrioventricular node repercussion; the SND involved the atrioventricular node in 56% of the patients, and there was a relation between the SND and carotid sinus syndrome in 18.8%. The follow-up revealed, in all patients, a complete remission of the symptoms, and when we repeated the carotid sinus massage in the first evaluation, there was a response like in the surgery room, in all patients. CONCLUSIONS: There is a significant number of patients with SND and carotid sinus syndrome. The carotid sinus massage performed in the surgery room does not influence the test sensitivity and specificity in the diagnosis of carotid sinus syndrome. The authors think that carotid sinus massage should be considered in the protocol that defines the pacing mode, in patients with SND, and that influence the choice of pacemaker in 18.8% of patients.

Aged↗