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Biomedical subjects

R Mora

Publications and source records attributed to R Mora.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Comparative study of sevoflurane and nitrous oxide versus halothane and nitrous oxide in pediatric anesthesia: efficacy and hemodynamic characteristics during induction].

OBJECTIVES: To study the efficacy, side effects and hemodynamics of anesthetic induction in pediatric patients using sevoflurane and nitrous oxide or halothane and nitrous oxide. PATIENTS AND METHODS: We studied 80 pediatric ASA I-II patients aged between 1 and 10 years old scheduled for infraumbilical surgery of short duration. The patients were randomly assigned to two groups of 40 to receive one of the two drug combinations. All the children were premedicated with nasal midazolam 0.2 mg.kg-1. Induction was by inhalation of increasing concentrations of sevoflurane or halothane. The maximum inspired concentration during induction was 7% for sevoflurane and 3% for halothane. We analyzed induction time, side effects and hemodynamic variables. RESULTS: The induction time was 2.06 +/- 0.5 min for halothane and 1.6 +/- 0.6 min for sevoflurane (p < 0.01). We observed no differences between the groups in coughing, laryngospasm, bronchospasm, secretions, apnea, nausea, vomiting, agitation or hiccoughing. Supraventricular beats appeared in 22.5% of patients in the halothane group and in 5% of the sevoflurane group. Induction with both anesthetics caused significant decreases from baseline blood pressure levels but no significant changes in heart rate. CONCLUSIONS: Inhaled sevoflurane in 60% nitrous oxide provides rapid but gentle anesthetic induction, with hemodynamic stability and a low incidence of airway complications. Sevoflurane is therefore a reasonable alternative to halothane for pediatric surgery.

Anesthesia, Inhalation↗
PubMed1997

Static and dynamic posturography in prevalent laterally directed whiplash injuries.

Static and dynamic posturography was used to study patients who had experienced a prevalent laterally directed whiplash in a car accident. Results of both static and dynamic examinations were recorded. Findings showed that the whiplash injury had provoked shifting of the pressor center of the body toward a side that was at least indicative of the kind of cervical twist experienced, even when not corresponding to the prevalent direction of the trauma incurred.

Adult↗
PubMed1997

Growth factor and cytokine-regulated hyaluronan-binding protein TSG-6 is localized to the injury-induced rat neointima and confers enhanced growth in vascular smooth muscle cells.

Hyaluronan (HA) and HA-binding proteins have been implicated in a diverse array of biological processes, including development, tissue repair, and tumor invasion. However, the role of HA and HA-binding proteins in atherosclerosis and restenosis is poorly understood. PS4 (TSG-6) is a HA-binding protein expressed by cultured vascular smooth muscle cells (SMCs) in response to serum and growth factor stimulation. To delineate a possible role for TSG-6 in vascular disease progression, we have characterized its expression in cultured SMCs and in a rat vascular injury model, and we have studied the effect of constitutive overexpression of TSG-6 on SMC behavior. We found that interleukin-1 (IL-1) but not tumor necrosis factor or interleukin-6 was able to stimulate TSG-6 expression in SMCs. The IL-1 pathway could be distinguished from the growth factor pathway by its insensitivity to protein synthesis inhibitors. Furthermore, epidermal growth factor, fibroblast growth factor-1, and transforming growth factor-beta1 were all capable of augmenting maximum IL-1-induced expression of TSG-6. To gain further insight into the function of TSG-6 in SMCs, we examined the effect of constitutive overexpression of TSG-6 on these cells. We found that TSG-6-overexpressing cells grew >50% faster than control cells. Furthermore, this growth advantage became more evident in the absence of serum growth factors, with an average increase in cell number of 118% over control cells after 6 days. Consistent with these in vitro data, we observed intense immunostaining for TSG-6 in proliferating SMCs in the rat neointima after injury, whereas only an occasional cell was positive for TSG-6 in the medial layer and in nonballooned arteries. We conclude that the expression of TSG-6 is tightly controlled by growth factors and cytokines via two distinct pathways in SMCs and that overexpression of TSG-6 confers a growth advantage to these cells.

Animals↗
PubMed1997

Frontiers in Internal Medicine.

Clinical research in Internal Medicine has provided many scientific advances during the past few years. However, the newly generated information overrides the time available to read all of the medical literature regarding advances in Internal Medicine. The goal of this review is to summarize some of the most relevant improvements in clinical practice published over the last few years. From Cardiology to Pulmonology, the authors of this review expose in a succinct way what they and many of their peers consider to be the most transcendental information gathered from thousands of publications. The authors of this review article have attempted to avoid sensationalism by including facts instead of just simply optimistic preliminary findings that can mislead clinicians' decision making. The review is focused on information obtained through well-designed, prospective clinical trials and cohorts where the effectiveness of medical interventions and diagnostic procedures were tested.

Clinical Trials as Topic↗
PubMed1996

[Optokinetic nystagmus and visual-vestibular interaction in subjects with "whiplash injuries"].

We studied the behaviour of Vestibular Nystagmus (VOR), of Optokinetic Nystagmus (OKN) and of Visuo-Vestibular-Ocular-Reflex (VVOR) in seven normal subjects and in thirty-two patients who had undergone cervical trauma in an automobile accident with the so called "whiplash mechanism". Thirteen subjects underwent examination within the first three months after the accident (first group), six subjects between the third and the sixth months (third group). Ocular movements was recorded according to the usual method by means of a Tonnies electronystagmograph with eight channels. The subjects, head blocked, sat on a Tonnies rotatory chair Pro model which was placed in the middle of a rotatory cylindrical chamber 2 metres in diameter and 1.9 metres in height. The width internal area was covered with thirty-two black vertical contrast. The rotatory cylinder was lighted from above by a 100 W bulb and was driven by a direct current engine which turned it clockwise and counterclockwise up to 200 degrees/sec., maximum speed, with preset acceleration ranging from 1 degree to 2 degrees/sec. All the subjects underwent to Rotatory Vestibular Stimulation by Stop test from a constant angular velocity of 90 degrees/sec. with clockwise and counterclockwise rotation, "stare type" Optokinetic stimulation with a cylinder rotation velocity of 30 degrees/sec. for 60 seconds and to contemporary Rotatory Vestibular and Optokinetic Stimulation (VVOR) so that OKN was VOR counterdirectional. The results of our experience show a statistically significative mean gain decrease of VOR and VVOR nystagmus (beating OKN direction) calculated on the first three beats in the patients of the first group and a significative increase of OKN mean gain in all the patients of the three groups. Furthermore, in sixteen out of thirty-two patients (seven in the first group, two in the second and seven in the third) we observed (during VVOR examination, immediately after stop) a nystagmus beating VOR direction lasting from 3 to 15 seconds.

Adult↗
PubMed1994

Subunit composition of lipoprotein(a) protein.

We determined the molecular weight of four different apo(a) polymorphs by sedimentation equilibrium in 6 M guanidine hydrochloride in order to estimate the molar ratio of apo(a) to apoB in Lp(a). They had molecular weights of 289,000, 310,000, 341,000, and 488,000 and 15, 16, 18, and 27 kringle 4 domains, respectively. Their carbohydrate content was similar (23.2 wt %), as was their partial specific volume (0.682 mL/g). Knowing the mass of apo(a), we estimated the molar ratio of apo(a) to apoB from (1) the molecular weight of the protein moiety of the four respective parent Lp(a) particles as calculated from their mass and percentage composition and the mass of apoB, (2) the mass of apo(a) lost from Lp(a) upon its reduction and carboxymethylation, by determining the difference in mass between Lp(a) and Lp(a-), and (3) from the mass (measured by sedimentation equilibrium in 6 M guanidine hydrochloride) of the lipid-free apoB-apo(a) complex (1.06 x 10(6) daltons) of the Lp(a) particle with the smallest apo(a) polymorph by subtracting the mass of apoB. Our results obtained with each of the three different physicochemical methods indicated that the protein moiety of each of the four Lp(a) particles that was investigated consisted of a complex of two molecules of apo(a) and one molecule of apoB.

Apolipoproteins B↗
PubMed1994

The endothelial cell binding site for advanced glycation end products consists of a complex: an integral membrane protein and a lactoferrin-like polypeptide.

Advanced glycation end products (AGEs), formed as the result of the extended interaction of proteins with ketoses, modulate central properties of endothelial cells and mononuclear phagocytes by interacting with a cell surface binding site comprised of a novel integral membrane protein (receptor for AGE = RAGE) and a lactoferrin-like polypeptide (LF-L), the latter having sequence identity to lactoferrin (LF). To further understand this cellular binding site, the interaction of RAGE with LF-L and LF was characterized. By ligand blotting and a solid state competitive binding assay, 125I-LF-L and 125I-LF bound to RAGE immobilized on nitrocellulose membranes or polypropylene tubes in a time-dependent and reversible manner, demonstrating a high affinity component with Kd approximately 100 pM. The interaction of 125I-LF-L and 125I-LF with RAGE was independent of iron in LF and was competed by addition of an excess of unlabeled carboxyl-terminal portion of LF. Cross-linking studies with purified 125I-LF-L and RAGE, in the presence of disuccinimidyl suberate, showed a new, slowly migrating band, corresponding to a complex of RAGE and LF-L, and cross-linking on mouse aortic endothelial cells showed two new slowly migrating bands on immunoblotting visualized with both anti-RAGE IgG and anti-LF-L IgG. These data lead us to propose that the endothelial cell surface binding site for AGEs consists of LF-L bound noncovalently to RAGE anchored in the cell membrane.

Amino Acid Sequence↗
PubMed1993

In vitro formation of oxidatively-modified and reassembled human low-density lipoproteins: antioxidant effect of albumin.

In early atherogenesis, excess plasma lipoproteins accumulate into the arterial lesion-prone areas as modified and reassembled lipoproteins (MRLp) appearing mostly as lipid droplets and vesicles. In the present study we produced such MRLp, in a cell-free system, devoid of any component of extracellular matrix, by subjecting in vitro human low-density lipoproteins (LDL) to autoxidation or copper-induced oxidation, for up to 96 h. As visualized by negative staining electron microscopy, a large number of lipoprotein particles (Lp) were progressively transformed into aggregates (ALp), fused particles (FLp) and vesicles (VLp). These modifications were paralleled by peroxidation of the samples as revealed by chemical analysis of each MRLp fraction isolated by a three-step purification procedure. LDL peroxidation in the above conditions was inhibited by the presence of albumin as assessed by TBARS and lipid analysis, and by the lack of MRLp formation. This protective effect was independent of albumin source (bovine, human, rabbit) and occurs at an albumin/LDL ratio of 1 when Cu2+ was present, and at a ratio of 0.25 in autoxidative conditions. The results show that: (i) in vitro LDL autoxidation or copper-induced peroxidation in a cell-free system can generate modified and reassembled lipoproteins similar to those detected in vivo in the arterial intima at the inception of atherogenesis; (ii) Lp particles appear to be sequentially transformed in self-aggregates, droplets and vesicles; (iii) serum albumin can completely prevent these LDL alterations.

Antioxidants↗
PubMed1993

Isolation of amaranth flour proteins by fractionation procedures and sonication.

The use of whole and defatted amaranth flour for protein isolation of Osborne fractions is described. Extractability of prolamins, the minor fraction, increased from 2.8 to 5% by adding a reducing agent. Glutelins proved to be poorly solubilized (3.3%) in dilute acetic acid, but they reached a high solubility value (40.8%) using a borate buffer in the presence of a reducing agent and a detergent; solubility remarkably declined without the latter two chemicals. Sonication (a fast and simple technique) in the presence of a detergent proved to be more efficient, compared with stirring, for extractability of total unreduced proteins.

Albumins↗
PubMed1993

Regulation of human mononuclear phagocyte migration by cell surface-binding proteins for advanced glycation end products.

Nonenzymatic glycation of proteins occurs at an accelerated rate in diabetes and can lead to the formation of advanced glycation end products of proteins (AGEs), which bind to mononuclear phagocytes (MPs) and induce chemotaxis. We have isolated two cell surface-associated binding proteins that mediate the interaction of AGEs with bovine endothelial cells. One of these proteins is a new member of the immunoglobulin superfamily of receptors (termed receptor for AGEs or RAGE); and the second is a lactoferrin-like polypeptide (LF-L). Using monospecific antibodies to these two AGE-binding proteins, we detected immunoreactive material on Western blots of detergent extracts from human MPs. Radioligand-binding studies demonstrated that antibody to the binding proteins blocked 125I-AGE-albumin binding and endocytosis by MPs. Chemotaxis of human MPs induced by soluble AGE-albumin was prevented in a dose-dependent manner by intact antibodies raised to the AGE-binding proteins, F(ab')2 fragments of these antibodies and by soluble RAGE. When MP migration in response to N-formyl-Met-Leu-Phe was studied in a chemotaxis chamber with AGE-albumin adsorbed to the upper surface of the chamber membrane, movement of MPs to the lower compartment was decreased because of interaction of the glycated proteins with RAGE and LF-L on the cell surface. The capacity of AGEs to attract and retain MPs was shown by implanting polytetrafluoroethylene (PTFE) mesh impregnated with AGE-albumin into rats: within 4 d a florid mononuclear cell infiltrate was evident in contrast to the lack of a significant cellular response to PTFE with adsorbed native albumin. These data indicate that RAGE and LF-L have a central role in the interaction of AGEs with human mononuclear cells and that AGEs can serve as a nidus to attract MPs in vivo.

Animals↗
PubMed1992

Primitive synovial chondromatosis of the hip joint.

Primitive synovial chondromatosis of the hip is quite rare. Through the presentation of four new cases, the authors discuss the pathologic and clinical features of this disease and evaluate the performance of imaging studies, emphasizing the value of CT scan for confirmation of radiographic findings. The indication for surgical treatment is analyzed for each stage of the disease.

Adult↗
PubMed1991

Forage intake and nutrition of range goats in a shrubland in northeastern Mexico.

Voluntary intake and nutritive value of diets selected by goats grazing a shrubland at Marin county, N.L., Mexico were determined. Four esophageally cannulated Spanish female goats (average BW 35 kg), were used to collect extrusa samples monthly throughout 1 yr (June 1987 to May 1988). Organic matter intake (OMI) was estimated by total fecal collections from four castrated Spanish male goats (average BW 42 kg). Diets selected by goats were high in CP throughout the year (means = 18.9%). Available CP represented only about half the total CP. The ADF content of extrusa samples differed (P less than .05) among months, with high ADF values during winter months. Dietary lignin followed a similar pattern during the year. Goats consumed forage with sufficient amounts of Ca, Na, K, Mg, Cu, ZN, Mn, and Fe to meet requirements. The OMI of goats was different (P less than .05) among sampling periods. On the average, estimated OMI (means = 878.7 g/d) compared well with results of other studies in the area. Amounts of DE consumed by goats (1.1 Mcal DE/d) were not sufficient to meet requirements for maintenance plus low activity. High levels of browse in the diets presumably were responsible for low in vitro OM digestibility (means = 34.1%) throughout the year. Thus, productivity of range goats in these areas should be improved by supplementing with protein and energy.

Animal Feed↗
PubMed1990

Purification and partial characterization of extracellular liposomes isolated from the hyperlipidemic rabbit aorta.

Extracellular liposomes (EL) that accumulated in the aortic intima of rabbits on 2 weeks (prelesional stage) and 16 weeks (lesional stage) of diet-induced hyperlipidemia were isolated and purified by gel filtration, ultracentrifugation, and affinity chromatography on anti-apoB and anti-albumin Sepharose. The material obtained after each step was examined by negative staining electron microscopy, by protein analysis (SDS-PAGE, immunoblotting, autoradiography, uronic acid), and by lipid analysis for unesterified cholesterol (UC), cholesteryl esters (CE), phospholipids (PL), triglycerides (TG), thiobarbituric acid reactants (TBAR). EL represented the major constituent of intimal lipid deposits; their predominance on particulate beta-lipoproteins (LP) increased with the duration of hyperlipoproteinemia. As compared with serum low density lipoproteins (LDL) and beta-very low density lipoproteins (beta-VLDL), the crude EL fraction obtained after gel filtration and ultracentrifugation had a decrease in CE and TG, with augmentation of UC, PL, and apoB. After removal of apoB and some albumin by immunoadsorption, the purified EL fraction consisted only of UC, PL, and albumin. The albumin was resistant to proteolytic digestion with pronase, and reacted with anti-albumin antibody only after delipidation of EL. This indicated that albumin was trapped in the aqueous core of vesicles, presumably acting as a scavenger of oxygen-free radicals. TBAR was highly associated with intact or degraded beta-LP. The EL that accumulate in the aortic intima of hyperlipidemic rabbits represent the predominant form of lipid deposits, resulting from the transcytosed excess beta-LP, which is degraded and reassembled upon interaction with the extracellular matrix components.

Albumins↗
PubMed1990

[Use of atracurium for the prevention of fasciculations and succinylcholine myalgia in athletes undergoing orthopedic surgery].

The Authors report their clinical experience about the use of atracurium besylate in preventing succinylcholine-induced fasciculations and postoperative myalgias in fifty athletes (ASA class 1), submitted to arthroscopic meniscectomy. The patients were pretreated with atracurium 5 mg i.v. or saline solution in a double-blind fashion. After 2.5 minutes, succinylcholine 1.3 mg/kg was administered, and fasciculations were recorded on a scale ranging from 0 to 3. Twenty-four hours after surgery all subjects were questioned about myalgias occurrence, scored by a 0-3 scale. Fasciculations occurred in all patients who received saline and in 44% of those treated with atracurium. Myalgias on the postoperative day were observed in 80% of patients treated with saline solution, but only in 36% of patients who received atracurium. The difference between atracurium and saline solution was statistically significant (p less than 0.001) either for fasciculations or myalgias incidence. These findings show that atracurium 5 mg i.v. is effective in preventing succinylcholine-induced fasciculations and postoperative myalgias, and suggest atracurium as the drug of choice for this purpose, particularly in muscular subjects.

Adolescent↗