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R Gonzalez

Publications and source records attributed to R Gonzalez.

At least 163 records · Page 9Linked to original sources
PubMed1993

In vitro activation of hepatic glutathione reductase from mice by lobenzarit disodium.

Glutathione reductase activity from mice liver is significantly enhanced by lobenzarit disodium at concentrations between 0.3 and 1.5 mM. A maximum activation of almost 30% is achieved at a drug concentration of 0.9 mM. Similar results were observed with glutathione reductase from human leukocytes, but not with the enzyme from yeast. By preincubation with the enzyme from mice liver, lobenzarit also proved to prevent, at least partially, the immediate inhibition caused by the well-known thiol-reacting agents, thus indicating a protecting effect on the catalytically important thiol residue of the enzyme. The results here obtained explain in part the recently found hepatoprotective effect of lobenzarit disodium against acute liver toxicity induced by acetaminophen in mice.

Animals↗
PubMed1993

A comparative study of the diagnostic performance of amniotic fluid glucose, white blood cell count, interleukin-6, and gram stain in the detection of microbial invasion in patients with preterm premature rupture of membranes.

OBJECTIVE: Our aim was to compare the value of amniotic fluid tests for the detection of microbial invasion of the amniotic cavity and in the prediction of the amniocentesis-to-delivery interval and neonatal complications in patients with preterm premature rupture of membranes. STUDY DESIGN: Amniotic fluid was obtained by transabdominal amniocentesis from 110 consecutive patients with preterm premature rupture of membranes. Fluid was cultured for aerobic and anaerobic bacteria, as well as mycoplasmas. Amniotic fluid analysis included a Gram stain examination, white blood cell count, and glucose and interleukin-6 determinations. Logistic regression and survival techniques (proportional hazards model) were used for statistical analysis. RESULTS: (1) The prevalence of positive amniotic fluid cultures in patients with preterm premature rupture of membranes was 38% (42/110); (2) patients with microbial invasion had a shorter amniocentesis-to-delivery interval and a higher neonatal complication rate than patients with negative cultures; (3) the most sensitive test for the detection of microbial invasion of the amniotic cavity was amniotic fluid interleukin-6 determinations (cutoff 7.9 ng/ml) (sensitivity: for IL-6 80.9%; for white blood cell count 57.1%; for glucose 57.1%; for Gram stain 23.8%; p < 0.05 for all comparisons); (4) the most specific test for the detection of microbial invasion was the Gram stain of amniotic fluid (specificity: for Gram stain 98.5%; for white blood cell count 77.9%; for interleukin-6 75%; for glucose 73.5%; p < 0.01 for all); (5) of all amniotic fluid tests, interleukin-6 determination was the only test that had significant clinical value in the prediction of the amniocentesis-to-delivery interval and neonatal complications. CONCLUSION: Interleukin-6 concentrations in amniotic fluid are a better predictor of microbial invasion of the amniotic cavity, amniocentesis-to-delivery interval and neonatal complications than the amniotic fluid Gram stain, glucose, or white blood cell count in patients with preterm premature rupture of membranes.

Amniocentesis↗
PubMed1993

Vasopressin and oxytocin but not glucose stimulate hydrolysis of phosphatidylinositol and phosphatidylcholine in a hamster insulinoma.

HIT-T15 cells prelabeled with [3H]-arachidonate were incubated for 15 minutes at 37 degrees C in Krebs Ringer buffer (pH 7.1) in the presence and absence of various agonists. Radioactivity remaining in major phospholipids was measured at the end of incubation period. Oxytocin (1 microM), vasopressin (1 microM), and A23187 (5 microM) stimulated loss of radioactivity from phosphatidylinositol and phosphatidylcholine. No loss of radioactivity from either of the phospholipids, however, was detected in the presence of 10 mM D-glucose, an insulin secretagogue in HIT-T15 cells. The lack of phosphatidylinositol response to glucose was also evident when the cells were prelabeled with myo-[3H] inositol. The formation of inositol phosphates at 15 minutes was readily observed upon the treatment of myo-[3H] inositol-labeled cells with oxytocin or vasopressin but not glucose or A23187. Inability of glucose to stimulate phosphatidylinositol and phosphatidylcholine hydrolysis in beta cell-derived HIT-T15 cells contrasts sharply with results from studies with pancreatic islets, where hydrolysis of these two phospholipids is readily observed and thought to contribute to the signaling mechanism responsible for stimulation of insulin secretion.

Animals↗
PubMed1993

Free choline and choline metabolites in rat brain and body fluids: sensitive determination and implications for choline supply to the brain.

In the central nervous system, choline is an essential precursor of choline-containing phospholipids in neurons and glial cells and of acetylcholine in cholinergic neurons. In order to study choline transport and metabolism in the brain, we developed a comprehensive methodical procedure for the analysis of choline and its major metabolites which involves a separation step, selective hydrolysis and subsequent determination of free choline by HPLC and electrochemical detection. In the present paper, we report the levels of choline, acetylcholine, phosphocholine, glycerophosphocholine and choline-containing phospholipids in brain tissue, cerebrospinal fluid and blood plasma of the untreated rat. The levels of free choline in blood plasma (11.4 microM), CSF (6.7 microM) and brain intracellular space (64.0 microM) were sufficiently similar to be compatible with an exchange of choline between these compartments. In contrast, the intracellular levels of glycerophosphocholine (1.15 mM) and phosphocholine (0.59 mM) in the brain were considerably higher than their CSF concentrations of 2.83 and 1.70 microM, respectively. In blood plasma, glycerophosphocholine was present in a concentration of 4.58 microM while phosphocholine levels were very low or absent (< 0.1 microM). The levels of phosphatidylcholine and lyso-phosphatidylcholine were high in blood plasma (1267 and 268 microM) but very low in cerebrospinal fluid (< 10 microM). We concluded that the transport of free choline is the only likely mechanism which contributes to the supply of choline to the brain under physiological conditions.

Acetylcholine↗
PubMed1993

Histamine H1 receptor binding sites in mouse uterine horns.

1. The specific binding of both [3H]histamine and [3H]pyrilamine to crude membrane preparations obtained from mouse uterine horns was studied with the aid of radioligand binding techniques. 2. Saturation isotherms and binding of 300 nM of [3H]histamine in the presence of increasing concentrations of unlabelled histamine suggested the presence of two populations of [3H]histamine binding sites (IC50: 56 +/- 5.6 nM and 100 +/- 9.8 microM, respectively). 3. Pyrilamine displaced the high affinity binding site (IC50: 100 +/- 10 nM), while cimetidine displaced the low affinity one (IC50: 98 +/- 10 microM). 4. Saturation curve analysis by using [3H]pyrilamine as radioligand, revealed that H1 binding site varied according to the predominance of sexual hormones (Kd: 29 nM; 102 nM and 130 nM in uterine membranes from ovariectomized, diestrous and estrous, respectively). At the end of pregnancy Kd was found to be 71.1 nM.

Animals↗
PubMed1993

Silicone shedding from artificial urinary sphincter in children.

Silicone is an inert material used in all genitourinary prosthetic devices. Silicone particle shedding has been documented in adults with penile prostheses and artificial urinary sphincters. We searched prospectively for silicone particles in the peri-prosthetic tissue and regional lymph nodes in 6 children who underwent removal or exchange of an artificial urinary sphincter. The peri-prosthetic fibrous capsule was biopsied and examined by light and polarizing microscopy. Regional lymph nodes were biopsied if clinically enlarged and evaluated in a similar manner. Lymph nodes from 2 children without an artificial urinary sphincter served as controls. An artificial urinary sphincter was in place from 3 to 10 years (mean 4.3 years) and none of the sphincters demonstrated infection or erosion. Silicone particles were found in the peri-sphincteric tissue of 3 patients, which induced foreign body giant cell reaction in 2 and eosinophilic infiltrate in 1. Focal histiocytic proliferation around the cuff was seen in another case without silicone migration. There was fibrosis around the sphincter in all cases. No silicone was found in the regional lymph nodes. Silicone shedding was documented in 50% of our patients. X-ray energy dispersive spectroscopy was not performed, raising the possibility that it was under-detected. Long-term effects of silicone in children with an artificial urinary sphincter are unknown and warrant further study.

Child↗
PubMed1993

The development of tumors in experimental gastroenterocystoplasty.

Bladder augmentation with segments of the gastrointestinal tract is commonly used to treat patients with small or noncompliant bladders. Reliable data on the incidence of tumors in patients with enterocystoplasty are not available. In the small number of cases reported in the literature the mean latency period is approximately 18 years. We designed a study in Sprague Dawley rats to try to determine the risk of carcinogenesis in different types of augmentation cystoplasty and its possible relationship with infected urine, and to investigate the possibility of detecting the tumors by cytological analysis. We performed 30 gastrocystoplasties, 35 sigmoid cystoplasties, 30 ileocystoplasties and 10 sham operations, and used 10 nonoperated animals as controls. The animals were sacrificed upon completing 1 year of followup and bladder urine samples were collected at the time of sacrifice. Of 115 animals 86 were available for histological evaluation (26 gastrocystoplasty, 22 sigmoid cystoplasty, 18 ileocystoplasty, and all sham and control animals). Mean followup was 11.2 months in the gastrocystoplasty, 11.8 months in the sigmoid cystoplasty, and 12 months in the ileocystoplasty, sham and control groups. Multifocal or superficial transitional metaplasia was found in 65.4% of the gastrocystoplasty, 50% of the sigmoid cystoplasty and 55.5% of the ileocystoplasty animals. Proliferations that we classified as papillary hyperplasia were present in 53.8% of the gastrocystoplasty, 40.9% of the sigmoid cystoplasty and none of the ileocystoplasty rats. The proliferations occurred either at or close to the anastomosis between the bladder and the gastric or colonic patch, or in areas of transitional metaplasia. Cytological urinalysis was negative for neoplastic cells in all cases. No correlation was found between the occurrence of papillary hyperplasia and urinary infection. These data indicate that in rats transitional metaplasia is common in gastrocystoplasty, sigmoid cystoplasty and ileocystoplasty, and that papillary hyperplasia may occur near or at the anastomosis, or in areas of transitional metaplasia in either gastrocytoplasty or sigmoid cystoplasty. In contrast to other studies, we observed no examples of papillary hyperplasia in the ileocystoplasty group in this series. No transitional cell carcinomas or adenocarcinomas were identified in this study. It is not known if these papillary lesions have an increased malignant potential, thus further studies with longer followup are warranted.

Animals↗
PubMed1993

Urological aspects of sacrococcygeal teratoma in children.

Sacrococcygeal teratoma is the most common extragonadal germ cell tumor of infancy. Associated urological complications, most of which are reported in children with malignancy, include vesicoureteral reflux, ureteral and urethral obstruction, and neurogenic bladder. To evaluate the influence of tumor grade and type on adverse urological outcome we reviewed the charts of 29 children with sacrococcygeal teratoma and correlated urological problems to lesion type and grade. No correlation was noted between tumor grade and the incidence of urological complications. The most common urological complications were neurogenic bladder in 12% of the patients, ureteral obstruction in 10% and vesicoureteral reflux in 7%. The highest incidence of urological complications (81%) was seen in patients with type IV (presacral) disease. We recommend early radiographic and neurourodynamic evaluation in all children with sacrococcygeal teratoma.

Female↗
PubMed1993

Postoperative diuresis renography and ultrasound in patients undergoing pyeloplasty. Predictors of surgical outcome.

The authors reviewed 50 pediatric patients (56 renal units) who underwent pyeloplasty and had serial preoperative and postoperative diuresis renogram and ultrasound studies. Of those patients that clinically improved with surgery, 73% and 91% showed improved renographic patterns in postoperative studies at 3 and 12 months, respectively. Ultrasound demonstrated more gradual improvement in grade and pelvic diameters over longer study intervals. Diuresis renography is an excellent predictor of surgical outcome within 3 months of pyeloplasty and showed change well in advance of that seen on ultrasound. Sonography is better suited to longer term evaluation of grade, pelvic diameter, and renal size.

Adolescent↗
PubMed1993

The CD26 antigen is coupled to protein tyrosine phosphorylation and implicated in CD16-mediated lysis in natural killer cells.

The levels of CD26 expression, their capacity to induce protein tyrosine phosphorylation and their functional implication in natural killer (NK) cytolysis have been studied. It was found that only a small fraction (12-15%) of peripheral NK cells expresses CD26 compared with the high expression (99%) found in NK clones. The protein tyrosine phosphorylation mediated by means of CD26 activation was studied in NK cells treated with the anti-CD26 MoAb 134-2C2, and two new proteins of 50 and 21 kDa appeared phosphorylated in tyrosine residues. To study the influence of CD26 antigen in NK lysis, we analysed the lytic capacity of NK cells stimulated with different anti-CD26 MoAbs or after separation into CD26+ and CD26- subsets and using K562 as target cells. Under these conditions, no differences were found in the chromium release by the target cells. Redirected lysis through CD16 was also measured by arming the effector cells (CD26+ and CD26-) with anti-CD16 antibody and using K562 as target cells. It was found that CD26- cells showed significantly less CD16-dependent lysis than CD26+ cells. These results indicate that CD26 is related to the CD16-dependent lysis but not to NK cytolysis which may be caused by mediation of protein tyrosine phosphorylation.

Antibodies, Monoclonal↗
PubMed1993

Urethral atresia and the prune belly syndrome. Report of 6 cases.

An association between urethral atresia and the prune belly syndrome (PBS) has been recognised, but few reports discuss the outcome of treatment for these gravely ill patients. Of the 34 patients with prune belly syndrome evaluated at our institutions, 6 had urethral atresia (3 males and 3 females). Two of these patients died as neonates as a result of pulmonary insufficiency and 1 was stillborn. The common feature of the 3 surviving patients (2 males and 1 female) was the presence of a vesicocutaneous fistula. As neonates, 2 suffered from pulmonary insufficiency due to oligohydramnios. The mean length of follow-up for these 3 patients was 37 months (range 13-58). The urinary tract was decompressed in 2 patients by a formal vesicostomy performed early in life. The surviving girl has normal renal function following reconstructive surgery. Because both the bladder and urethra were absent in this patient, an ileocaecal bladder substitute and an appendiceal urethra were constructed. The 2 surviving boys both have renal insufficiency. One has received a renal transplant from a living relative and is doing well. In one of the boys, urethral atresia was initially managed by perineal urethrostomy and then by reconstructive surgery. Progressive catheter dilation was used on the other boy. Urethral atresia occurred in 18% of our patients with PBS; the incidence was equal in males and females. Survival correlated with the development of a spontaneous vesicocutaneous fistula. Two-thirds of the survivors developed end-stage renal failure.

Congenital Abnormalities↗
PubMed1993

Extracranial vertebral artery pseudoaneurysm presenting as subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: True aneurysms of the extracranial vertebral artery are rare. The usual pathogenesis of aneurysms in this location is either penetrating or blunt trauma with resultant pseudoaneurysm formation. We report a postpartum patient with a presumed traumatic pseudoaneurysm of the extracranial vertebral artery presenting with subarachnoid hemorrhage. CASE DESCRIPTION: A 41-year-old woman had three episodes of neck stiffness 1 month after an uncomplicated vaginal delivery. The last episode, 3 days before admission, was accompanied by intense neck and head pain and paresthesias that extended into the left arm, thumb, and forefinger. RESULTS: Lumbar puncture showed subarachnoid hemorrhage. Angiography revealed a left vertebral artery dissection from C6-7 to C3 with pseudoaneurysm at C5-6. Computed tomography demonstrated impingement of the C6 root at the foramen by this lesion. The lesion was successfully treated by balloon occlusion of the vertebral artery. CONCLUSION: We present a patient with an extracranial vertebral pseudoaneurysm with subarachnoid hemorrhage and cervical root impingement. To our knowledge, this is the first case of such a lesion presenting as subarachnoid hemorrhage. The lesion was successfully treated using endovascular techniques.

Adult↗
PubMed1993

International cooperation in analytical chemistry: experience of antidoping control at the XI Pan American Games.

We describe the experience of the international cooperation carried out for antidoping control at the XI Pan American Games. A temporary accreditation was granted by the International Olympic Committee to the accredited laboratory of Barcelona (Spain) to set up a Doping Control Laboratory in Havana. Two other laboratories from Mexico and Cuba contributed personnel, materials, and instrumentation. The main issues associated with the preparation and organization of the project are described. During 16 days, 741 urine samples were tested for stimulants, narcotics, anabolic steroids, beta-blockers, diuretics, cannabinoids, local anesthetics, and human chorionic gonadotropin by gas-liquid chromatography, gas chromatography/mass spectrometry, high-performance liquid chromatography, and immunoassay techniques. Analytical methodologies, quality-control strategies, and the main results are reported.

Acebutolol↗
PubMed1993

An ultrasound survey of gallbladder disease among Mexican Americans in Starr County, Texas: frequencies and risk factors.

The Mexican-American population of south Texas has been shown previously to have elevated frequencies of gallbladder disease, based on medical history. In the present study, ultrasonography was employed to screen 1004 randomly selected individuals aged 15 to 74 years. Among women, the frequency of previous cholecystectomy was 10.0%; the frequency of stones on ultrasound was 12.2%. In men, the respective frequencies were 1.7% and 6.3%. Highest frequencies of gallbladder disease occurred among those aged 45 years or above: 40.2% and 19.2% among women and men, respectively. Non-insulin-dependent diabetes mellitus, obesity, and hypertension were also markedly elevated in this population. Overall, more than 40% of the population had either gallbladder disease, non-insulin-dependent diabetes, obesity, or hypertension. Among those older than 45 years, 70% had one or more of these chronic conditions. Examining the associations of gallbladder disease with other chronic diseases or measures of lipids, lipoproteins, and apolipoproteins demonstrates that factors predictive of or associated with cholecystectomy are different from those for gallstones by ultrasound. Diabetes and obesity show the strongest associations with cholecystectomy among women under 45 years (women with diabetes being 6.8 times as likely to have had a cholecystectomy than those without diabetes). Testing an extensive array of lipid-related measures resulted in no clear patterns, with the possible exception of alpha-lipoprotein and related measures. That the Mexican-American population is relatively young and experiencing extremely rapid growth indicates that the burden of chronic disease in general and gallbladder disease in particular will increase dramatically in the coming years.

Adolescent↗
PubMed1992

Selective decrease of CD26 expression in T cells from HIV-1-infected individuals.

The decrease of CD4+ cells in AIDS patients is widely documented, although the selective loss within different subsets of CD4+ cells and the mechanisms involved in this phenomenon are controversial. In the present report we have analyzed the proliferative response to Ag and mitogen of peripheral blood T lymphocytes from HIV-infected individuals, the phenotype profile of CD26+ and CD26- subset of cells and their infectivity by the HIV. The expression of CD26 Ag, either in CD4+ or CD8+ cells, was clearly diminished in all the patients tested. On the other hand, the expression of CD29 seems not to be affected, nevertheless T cells from these patients were unable to generate a proliferative response against soluble Ag. In 11 out of 13 patients, polymerase chain reaction studies demonstrated that the CD26- subset of CD4+ cells was the main reservoir for HIV-1 in infected individuals and HIV-1 virus preferentially infected in vitro CD4+/CD26- subpopulation. This capacity for preferential infectivity, together with the selective loss of cells expressing CD26 Ag, helps to explain the progressive impairment in the immune system of these patients and sheds new light on our understanding of the AIDS pathophysiology.

Acquired Immunodeficiency Syndrome↗