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Biomedical subjects

E Ruiz

Publications and source records attributed to E Ruiz.

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

Copper(II) complexes with 4-amino-N-[4,6-dimethyl-2-pyrimidinyl]benzenesulfonamide. Synthesis, crystal structure, magnetic properties, EPR, and theoretical studies of a novel mixed mu-carboxylato, NCN-bridged dinuclear copper compound.

New Cu(II) complexes of sulfamethazine (4-amino-N-[4,6-dimethyl-2-pyrimidinyl]benzenesulfonamide, HL) [Cu(2)(CH(3)COO)(2)(L)(2)].2dmf (1) and ([Cu(L)(2)].2H(2)O)(infinity) (2) were prepared and structurally characterized. Compound 1 crystallizes in the monoclinic system, space group P2(1)/n, with a = 8.9486(9) A, b = 15.0956(12) A, c = 16.542(3) A, beta = 105.584(15) degrees, and Z = 2. Compound 2 crystallizes in the monoclinic system, space group P2(1)/c, with a = 13.8097(8) A, b = 14.5765(4) A, c = 13.7853(15) A, beta = 96.033(9) degrees, and Z = 1. In compound 1 two copper ions are linked by two syn-syn acetates and two nonlinear NCN bridging groups pertaining to the deprotonated sulfamethazine ligands. Each copper center presents a nearly square planar geometry. Magnetic susceptibility data for 1 show a strong antiferromagnetic coupling with 2J = -216.7 cm(-)(1). The EPR spectra at the X- and Q-band frequencies present the signals corresponding to the dinuclear entity, being the zero-field splitting parameter, D = 0.265 cm(-)(1). The antiferromagnetic exchange coupling is discussed using DFT calculations on some model compounds with NCN bridging ligands and also on model structures with mixed mu-acetato and NCN bridges. The copper in the polymeric compound 2 is five coordinate. The CuN(5) chromophore has a highly distorted square pyramidal geometry with small axial N-Cu-N angles of 65.53(14) and 59.90(13) degrees. In the structure a sulfamethazinate anion binds to one copper through the sulfonamido and pyrimidine N atoms and to an adjacent copper via the amino N atom.

Journal Article↗
PubMed2001

Exchange coupling in carboxylato-bridged dinuclear copper(II) compounds: a density functional study.

A computational study of the exchange coupling is presented for a selected sample of carboxylato-bridged dinuclear copper(II) compounds. Model calculations have been used to examine the influence of several factors on the coupling constants: a) the electron-withdrawing power of the bridging ligands; b) the nature of the axial ligands; c) the number of bridging carboxylato groups; d) some structural distortions frequently found in this family of compounds; and e) the coordination mode of the carboxylato bridge. Coupling constants calculated for some complete structures, as determined by X-ray diffraction, are in excellent agreement with experimental data, confirming the ability of the computational strategy used in this work to predict the coupling constant for compounds for which experimental data are not yet available.

Journal Article↗
PubMed2001

Sigmoid cystoplasty with argon beam without mucosa.

PURPOSE: Intestinal bladder augmentations have well recognized complications, including mucus production, metabolic abnormalities and perforation. These complications may be avoided if the intestinal mucosa is not incorporated in the urinary tract. We report our experience with sigmoid cystoplasty without mucosa using argon beam, and describe the clinical, urodynamic, ultrasound and pathological results. MATERIALS AND METHODS: We performed sigmoid cystoplasty without mucosa in 26 patients and with argon beam over the mucosa before it was removed in 6 boys and 4 girls with a mean age of 8 years (range 3 to 14). All patients had neurogenic bladder as the initial disease. Indications for augmentation were poor bladder compliance, low bladder capacity, hydronephrosis and urinary incontinence. Mean followup was 18 months (range 8 to 40) and included ultrasound, urodynamic evaluation, renal function and clinical assessment. In all patients intraoperative biopsies were done. In 8 of the 10 patients endoscopic biopsies of the augmented segment were obtained between 6 months and 2 years postoperatively. The operation consisted of the Goodwin technique without mucosa, which was treated with argon beam before it was removed. RESULTS: The 10 patients are dry on intermittent clean catheterization with intervals of greater than 4 hours. There have been no clinical urinary tract infections. Two patients presented with peristaltic contractions and no symptoms. Bladder capacity increased from 80 (range 45 to 200) to 300 (220 to 400) ml., and mean postoperative compliance was 15 ml./cm. H2O (range 9 to 38). There were no significant changes in the urodynamic data between patients treated with sigmoid cystoplasty without mucosa only and with argon beam. Intraoperative biopsies after treatment with argon beam showed damaged mucosa and muscularis mucosa, and intact serosa, muscularis and submucosa layers. On the 8 argon beam postoperative biopsies the sigmoid submucosa was covered with a pseudostratified metaplasia of connective tissue with collagen fibers without scars (trichromic technique). CONCLUSIONS: Sigmoid cystoplasty without mucosa with argon beam is easy to perform. The clinical and urodynamic results have been satisfactory, and use of argon beam prevents postoperative bleeding and residual glands.

Adolescent↗
PubMed2001

Single distal ureter for ureterocystoplasty: a safe first choice tissue for bladder augmentation.

PURPOSE: Recently, the use of ureter for bladder augmentation has gained wide acceptance due to a lower complication rate compared to gastrointestinal segments. Unfortunately, the presence of a severely dilated urinary tract implicates loss of function of a renal unit which is often not demonstrated at diagnosis. Conversely, many patients present with 1 or both ureters mildly dilated because of vesicoureteral reflux or functional obstruction. In these cases the use of a single distal ureter seems to be a good option. We report our experience and long-term followup with this subset of patients. MATERIALS AND METHODS: Between December 1994 and November 1998, 17 females and 5 males 1.5 to 15.7 years old (mean age 7.2) with a low capacity, poorly compliant bladder underwent ureterocystoplasty with a single distal dilated ureter. Diagnosis included myelomeningocele in 13 cases, central neurogenic bladder in 3, neurogenic nonneurogenic bladder in 2, congenital spinal cord injury in 2, sacral agenesis in 1 and giant sacral teratoma in 1. All but 2 patients complained of recurrent febrile urinary tract infections. Variable degrees of hydronephrosis were observed in all patients. Vesicoureteral reflux was detected in 14 patients and was bilateral in 3. Five patients presented with chronic renal failure. Before surgery 19 patients were on clean intermittent catheterization and prophylactic antibiotics. The segments of ureter used for augmentation ranged from 9 to 14 cm. long (mean 11) and from 0.8 to 2.5 cm. in diameter (mean 1.3). The more distal piece of the ureter was kept unopened to preserve vascular supply. Simultaneous procedures included transureteroureterostomy in all 22 patients, appendicovesicostomy in 10, bladder neck continence procedures in 4 and ureteroneocystostomy in 3. Clinical, radiological and urodynamic evaluation was done 6 months postoperatively and yearly thereafter. RESULTS: Followup ranged from 12 to 60 months (mean 22). Of the patients 19 are dry on clean intermittent catheterization at 4-hour intervals and 6 have had 9 symptomatic urinary tract infections. Hydronephrosis resolved in 14 patients, improved in 6 and remained unchanged in 2. On urodynamics median increase in capacity less than 30 cm. pressure was 177% (range 11% to 560%). When comparing capacity less than 30 cm. water to normal expected capacity for age and weight, 50% of the cases reached or exceeded theoretical capacity while the rest reached 63% to 89% (mean 76%). Long-term complications included persistent reflux in 1 case, deterioration of bladder function without clinical impairment in 1 and spontaneous perforation of the ureteral patch in 1 requiring colocystoplasty. CONCLUSIONS: Although increase in bladder capacity is not always optimal with the use of a distal dilated ureter, it is good enough to ensure a good clinical outcome and allow an adequate catheterization interval with a low complication rate in the long term, thus avoiding use of a piece of gut or stomach to perform bladder augmentation in nearly all patients.

Adolescent↗
PubMed2001

Effects of CRH and ACTH administration on plasma and brain neurosteroid levels.

The 3alpha-hydroxy ring A-reduced metabolite of progesterone, 3alpha-hydroxy-5alpha-pregnan-20-one (allopregnanolone) is among the most potent known ligands of the gamma aminobutyric acid (GABA) receptor, designated GABA-A, in the central nervous system. We determined by RIA serum levels of progesterone (PROG), 5-alpha-dihidroprogesterone (DHP) and allopregnanolone in male and female rats after corticotropin releasing hormone (CRH) and adrenocorticotropin hormone (ACTH) administration. Allopregnanolone was undetectable in plasma and brain of control males but detectable in plasma and brain of males injected with CRH and ACTH and of control and similarly treated females. Allopregnanolone increased in the plasma and brain after CRH and ACTH administration in all cases. The data demonstrate that the administration of CRH plus ACTH results in a rapid increase of the neuroactive steroid allopregnanolone in the brain of males and females to levels known to modulate GABA-A receptor function. Thus, stress could regulate neurosteroid biosynthesis via the hormones ACTH and CRH.

20-alpha-Dihydroprogesterone↗
PubMed2001

Study of garlic extracts and fractions on cholesterol plasma levels and vascular reactivity in cholesterol-fed rats.

Garlic is known for its pharmacologic and nutritional properties. In previous studies, garlic elicited a reduction in plasma levels of lipids by inhibiting hepatic cholesterol synthesis. The aim of this study was to investigate in an in vivo model the effects of garlic extract and some fractions on cholesterol levels and vascular reactivity in cholesterol-fed rats. Rats were fed a cholesterol-enriched diet for 16 wk and were divided into 10 groups as follows: control and hypercholesterolemic diet groups, 4 groups fed frozen garlic fractions and 4 groups fed raw garlic fractions with different doses. Blood samples were obtained to analyze HDL and LDL cholesterol levels. After treatment, rats were killed. The heart, liver and kidneys were weighed; the aorta was isolated, mounted in organ chambers and vascular reactivity was tested. Plasma concentration of cholesterol was 58 mg/dL (100%) at the beginning of the study and increased to 102 mg/dL (153%; hypercholesterolemic group) at the end of the treatment. Plasma total cholesterol decreased in all groups treated with garlic; moreover, this effect was higher in rats fed raw garlic fractions and extracts. LDL decreased significantly with respect to the hypercholesterolemic group in all groups treated with garlic fractions and extracts (P: < 0.01); however, an increase in HDL was found in those treated with frozen fractions and extracts. The liver:body weight ratio decreased in all treated groups. The relaxing effect of acetylcholine (ACh) was enhanced in arteries contracted with noradrenaline (NE). These data suggest that garlic fractions could prevent diet-induced hypercholesterolemia and vascular alterations in the endothelium-dependent relaxation associated with atherosclerosis.

Acetylcholine↗
PubMed2000

Is equilibrium of aligned Kerr black holes possible?

We show that equilibrium of two Kerr black holes can be achieved by placing between them a relativistic disk or a third Kerr black hole, the latter case demonstrating the existence of equilibrium configurations in the purely black hole systems with the number of constituents more than two.

Journal Article↗
PubMed2000

Effects of acute alcohol intoxication on growth axis in human adolescents of both sexes.

We previously reported the deleterious effects of acute alcohol intoxication (AAI) on pituitary-gonadal and pituitary-adrenal axes hormones in human adolescents. In the present paper we studied the effects of AAI on the growth axis hormones, and the possible contribution of the insulin-glucose axis to the alcohol-induced dysfunction of the growth axis in human adolescents. Blood samples were drawn from adolescents that arrived at the emergency department with evident behavioural symptoms of drunkenness (AAI) or with nil consumption of alcohol (controls [C]). AAI produced in the adolescents of both sexes in our series: a decrease in growth hormone (GH) levels, without significant alteration of either insulin-like growth factor-I (IGF-I) or insulin-like growth factor binding protein-3 (IGFBP3); an increase in plasma glucose and a decrease in insulin in the female adolescents but not in the males. Males and females undergo a significant period of bone growth during adolescence. Growth axis hormones play an important role in the pubertal spurt. Thus, ethanol consumption during adolescence could have long-lasting deleterious effects on this aspect of development. In industrialised countries, around 35% of alcohol drinkers are under 16 years old, therefore the result of this study should be made known to adolescents and the appropriate authorities.

Adolescent↗
PubMed2000

Magnetic coupling in end-to-end azido-bridged copper and nickel binuclear complexes: a theoretical study.

The influence of structural parameters on the exchange coupling J between metal atoms in end-to-end azido-bridged binuclear complexes of Cu(II) and Ni(II) has been studied by means of density functional calculations. For the case of double-bridged Cu(II) compounds, four ideal pentacoordinate models have been employed in which the coordination spheres of the two metal atoms are either a trigonal bipyramid or a square pyramid, connected through equatorial or axial bridges. The distortion from those ideal geometries along a Berry pathway has also been analyzed. For the hexacoordinate Ni(II) compounds, models with two or one bridging ligands have been studied. The effect of the bridging M-N-N bond angles on the exchange coupling has been analyzed for both the Cu(II) and Ni(II) complexes.

Journal Article↗
PubMed2000

Effect of trandolapril on vascular responsiveness in cholesterol-fed rabbit-isolated arteries.

According to the World Health Organisation, cardiovascular disorders are one of the main causes of morbi/mortality in the western world. The effect of trandolapril (0.3 mg kg(-1) day(-1)), a non-sulphydryl angiotensin-converting enzyme (ACE) inhibitor, on the vascular responsiveness in aorta isolated from hypercholesterolemic rabbits was examined. Three groups of rabbits (n=30) were used: Group 0 (control group); Group 1 (hypercholesterolemic group, 0.5% (wt/wt) cholesterol-enriched diet) and Group 2 (hypercholesterolemic+trandolapril 0.3 mg kg(-1) day(-1)). After 18 weeks of treatment, the rabbits were killed and the thoracic aorta, proximal coronary and mesenteric (5th branch) arteries were isolated, cleaned off and mounted in an organ bath. Trandolapril had no significant effect on plasma cholesterol, high density lipoprotein (HDL) or low density lipoprotein (LDL). Despite the lack of effect of the drug on the above-mentioned parameters, treatment with trandolapril improved endothelium-dependent relaxation induced by acetylcholine in aortic and mesenteric rings from hypercholesterolemic rabbits treated with trandolapril. The relaxation induced by 10(-5) M acetylcholine were 65.0+/-4.0%; 24. 0+/-9.4% (P<0.01, n=10) and 51.3+/-7.0% (P<0.01, n=10) in aortic rings from Groups 0, 1 and 2, respectively, and 50.0+/-12.0%; 10. 1+/-10.0% (P<0.01, n=10); 61.0+/-9.7% (P<0.01, n=10) in small mesenteric rings from Groups 0, 1 and 2, respectively. In addition, trandolapril treatment improved the increase in serotonin-induced contraction in proximal coronary arteries with respect to the hypercholesterolemic group. On the other hand, we did not find any differences among the group in endothelium-independent relaxation induced by sodium nitroprusside. These results provide evidence that trandolapril restores endothelium-dependent relaxation in hypercholesterolemic rabbit-isolated arteries. These data suggest that trandolapril might have beneficial action in the prevention of vascular alteration involved in atherosclerosis.

Acetylcholine↗
PubMed2000

Effect of somatostatin on resistance and on capacitance rabbit isolated arteries.

The effects of somatostatin, a tetradecapeptide isolated from hypothalamus extracts, were studied on the vascular reactivity of aorta and mesenteric arteries isolated from rabbits. We also investigated whether or not Ca(2+) movements were implicated in these effects. Rabbit aorta and mesenteric (fifth branch) arteries were isolated, cleaned off, and mounted in an organ bath containing Godfraind solution or physiological saline solution (PSS), respectively. Somatostatin (10(-8)-10(-4) M) produced a concentration-dependent inhibition of the contractile responses induced by high K(+) (80 mM) or noradrenaline (10(-6) M in aorta or 10(-4) M in mesenteric arteries) in both arteries studied. The inhibitory effect of somatostatin was greater in mesenteric resistance vessels (IC(50) 3.1+/-2.3x10(-5) M, and 5.2+/-4.8x10(-8) M with KCl and noradrenaline, respectively). Contractile responses produced by the addition of Ca(2+) (1-5 mM) to Ca(2+)-free high K(+) solution were also concentration dependently inhibited by somatostatin in aorta. Furthermore, somatostatin decreased noradrenaline-induced contraction attributed to intracellular Ca(2+) release in aorta, and inhibited 45Ca(2+) uptake stimulated by high K(+) or by noradrenaline. However, it did not modify 45Ca(2+) uptake in resting mesenteric resistance arteries. Taken together, these results suggest that somatostatin exerts an inhibitory effect on vascular contractions induced by some stimulating agents in different arteries isolated from rabbits, being more potent in mesenteric arteries.

Animals↗
PubMed2000

Asymmetry and magnetism in bis(oximato)-bridged heterobimetallic compounds: a computational approach.

A density functional study of exchange coupling was carried out for a series of heterobinuclear oximato-bridged transition metal complexes. Model calculations were used to examine the influence of the electronic configuration of the metal atoms on the coupling constants. This analysis was complemented by a study of the variation of the coupling constant with the most usual structural distortions within this family of compounds. The influence of the nature of the terminal ligands as well as that of the symmetry on the bridge were also investigated.

Journal Article↗
PubMed2000

Effects of acute alcohol intoxication on pituitary-gonadal axis hormones, pituitary-adrenal axis hormones, beta-endorphin and prolactin in human adolescents of both sexes.

Teenage drinking continues to be a major problem in industrialized countries, where almost 35% of alcohol drinkers are under 16 years old. In the present paper we studied the effects of acute alcohol intoxication (AAI) on the pituitary-gonadal (PG) axis hormones, and the possible contribution of pituitary-adrenal (PA) axis hormones, beta-endorphin (BEND), and prolactin (PRL) to the alcohol-induced dysfunction of PG axis hormones. Blood samples were drawn from adolescents that arrived at the emergency department with evident behavioral symptoms of drunkenness (AAI) or with nil consumption of alcohol (controls [C]). Our results demonstrated that AAI produces in adolescents a high increase in plasma PRL, ACTH, and cortisol (F), and a contradictory behavior of testosterone (T) according to gender: plasma T was increased in females and decreased in males. ACTH and PRL correlated positively with F, dehydroepiandrosterone-sulphate (DHEAS) and T in females, which suggests that PRL and ACTH could synergistically stimulate adrenal androgen production. In contrast, the decrease in T and increase in BEND in males suggests that AAI could have an inhibitory effect on testicular T, perhaps mediated by BEND. The hormones studied are involved in the development of secondary sexual characteristics and the growth axis during adolescence. The deleterious effects of alcohol abuse should be made known to adolescents and the appropriate authorities.

Acute Disease↗
PubMed2000

[Residual pleural thickening in tuberculous pleuritis. Associated factors]].

BACKGROUND: To study the factors related to the development of residual pleural thickening in pleural tuberculosis. PATIENTS AND METHODS: We studied 39 patients with tuberculous pleural effusion. A chest X-ray was taken of each patient at the end of treatment. The patients' medical histories, pleural fluid findings and diagnostic chest films were evaluated. Residual pleural thickening was defined as thickening that was visibly greater than 2 mm in the lower side portion of the chest film. RESULTS: Residual pleural thickening developed in 26% of patients and was found mainly in men (RR = 3.86). In no patients with Löwenstein-Jensen cultures positive for Mycobacterium tuberculosis did pleural complications develop. CONCLUSION: Residual pleural thickening is a common complication of tuberculous pleural effusion. Residual pleural thickening in tuberculous pleurisy occurs more often in men and older patients, and in cases in which pleural liquid culture is negative for M. tuberculosis.

Adolescent↗