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R Lopez

Publications and source records attributed to R Lopez.

At least 73 records · Page 4Linked to original sources
PubMed1998

European multicentre evaluation of the Super Aution SA-4220 urinalysis analyser.

A multicentre evaluation of the urine test strip analyser Super Aution-4220 was carried out in six laboratories. The analytical performance of the instrument with regard to imprecision, linearity, detection limit, drift, carry-over and method comparison was studied. Using the Aution stick 8 test strip the pH, glucose, protein, ketones, bilirubin, blood, urobilinogen and leukocyte esterase were analysed. Specific gravity measurements were performed by refractive index method. Within-run and between-run imprecision determined at three levels of analyte were good. No carry-over was observed. Obtained results were linear through all the described analytical range. No significant drift was detected. Method comparison with some quantitative methods was performed and showed a good correlation with most of the analytes. The study of interferences showed minor interferences by common therapeutic drugs with the measurement of some analytes. During the assessment period of about 6 months no breakdown occurred in any laboratory. The Super Aution urine analyser appeared to be a highly automated analyser of urinary test strips. The operation was simple and the maintenance required only a few minutes a day.

Artifacts↗
PubMed1998

Abscess formation within a parasagittal meningioma. Case report.

The authors present the case of a 78-year-old woman who developed right lower-extremity paralysis after a focal seizure. Neuroradiological studies revealed a small parasagittal meningioma, which at the time of resection was found to contain a bacterial intratumoral abscess secondary to Proteus mirabilis. This is only the second reported case of intratumoral abscess formation in a meningioma and the first such occurrence to be reported in an otherwise healthy, immunocompetent individual.

Aged↗
PubMed1998

[Therapy of bacterial vaginosis. Prospective clinical study ot the efficacy and tolerability of quaternary ammonium salts vs. clindamycin].

BACKGROUND: To evaluate the efficacy and safety of intravaginal quaternary ammonium antimicrobial compounds (SQA) versus clindamycin 2% intravaginal cream (CL) in the treatment of bacterial vaginosis (VB). MATERIALS AND METHODS: One hundred-thirty-three patients affected by VB were enrolled in the study from January 1995 to October 1997. Patients were classified according to Amsel's criteria and/or to the indications of the Scandinavian Society of Bacterial Vaginosis. Twenty-three patients were initially excluded from the study, and 110 patients were randomized in two groups, SQA versus CL. Patients were reevaluated after 3 weeks, 3 months and 6 months from the end of therapy. The safety of treatment was also investigated. RESULTS: Of 110 patients, 59 were treated with SQA and 51 with CL. One hundred (90.9%) patients completed the therapy and were subjected to the first control after 3 weeks from the end of therapy. A significant reduction of most of the symptoms and all signs of VB was observed in the group treated with SQA. Similarly, a significant reduction of most of the symptoms (vaginal and urinary in particular) and all signs of VB was observed in the group treated with CL. The percentage of response was 86.7% for SQA group and 87.2% for CL group. Moreover, after 3 months from the end of therapy, 47.2% and 50% of the patients treated with SQA and CL, respectively, recurred, and after 6 months 78.5% and 75% of the patients recurred, respectively. CONCLUSIONS: SQA treatment conferred 86.7% of response after 3 weeks from the end of therapy, with poor side effects and a good compliance in good keeping with the results obtained with CL treatment.

Adolescent↗
PubMed1997

Methionine deprivation and methionine analogs inhibit cell proliferation and growth of human xenografted gliomas.

Growth of numerous malignant tumors depends on an exogenous methionine (MET) supply, while endogenously synthesized MET supports normal cell proliferation. Because an antitumor effect should be obtained by aggravating the altered MET metabolism in gliomas, MET dependency of human xenografted gliomas was evaluated and a therapeutic approach using MET deprivation or MET analogs to induce MET starvation was applied. In vitro proliferation inhibition of glioma cell lines by MET deprivation and two MET analogs, ethionine (ETH) and trifluoromethylhomocysteine (TFH), was measured. Proliferation of 7 human glioma cell lines tested was inhibited in MET-free medium, and was poorly or not reversed by homocysteine (HCY). ETH or TFH (concentration range: 0.005-2 mg/ml) inhibited proliferation of all cell lines tested. MET analog-induced inhibition was abolished by MET and enhanced by HCY. Cell-cycle alterations due to MET deprivation were optimally assessed after 30 h of culture and bromodeoxyuridine incorporation. In MET- medium, cells were arrested in the G1-phase. ETH induced a dramatic accumulation of cells in the G2-phase. ATP contents were reduced by MET analogs only in HCY+ medium, suggesting complementary effects of MET analogs and HCY. Human glioma bearing nude mice were fed an amino acid-substituted MET- HCY-supplemented diet (MET-HCY+) and/or treated with MET analogs, injected intraperitoneally daily. Using two human xenografted tumors derived from gliomas, antitumor effects were obtained by subjecting tumor-bearing nude mice to MET starvation. TG-1-MA was more sensitive to MET depletion (40% of growth inhibition, P < 0.10) than TG-8-OZ (no growth inhibition). Antitumor effects of a MET-HCY+ diet and 200 mg/kg of ETH were potentiated when co-administered to glioma-bearing mice (77% GI, P < 0.025 and 67%, P < 0.0057 to TG-1-MA and TG-8-OZ respectively). A dose-response effect with no toxicity was obtained when the ETH dose was increased 10 fold. Potentiation of the effects of ETH and a MET-free diet indicates that they probably act on the same pathway but not the same target. In conclusion, experimentally induced MET deprivation and MET-analog treatment retarded the growth of human gliomas. Combination of MET-analog therapy with MET substitution by HCY enhanced their respective effects.

Adenosine Triphosphate↗
PubMed1997

Metabolic effects in rats of verapamil alone and in combination with captopril.

The metabolic effects of verapamil alone and in combination with captopril were investigated in rats. Animals received the maximum recommended doses for humans (per kg body weight per day) over a 2-week period. Verapamil had no significant effects on serum biochemistry, but caused a significant increase in serum potassium level and significant reductions in the rates of intestinal absorption of glucose and calcium. Verapamil/captopril had a number of significant effects on serum lipid profile (increased total cholesterol, increased HDL-cholesterol, and reduced LDL-cholesterol), and also provoked an increase in serum alanine amino-transferase activity and in serum glucose levels. The combination treatment caused a significant increase in serum chloride levels, but had no effect on intestinal absorption.

Alanine Transaminase↗
PubMed1997

Laparoscopic technique in the management of Spigelian hernia.

Spigelian hernias are uncommon, and preoperative diagnosis is often difficult. The use of the laparoscope has simplified the diagnosis and subsequent repair of these rare hernias. We report a case diagnosed and repaired using laparoscopic techniques of fascia approximation, mesh reinforcement, and reperitonization.

Female↗
PubMed1997

Vagal regulation during bottle feeding in low-birthweight neonates: support for the gustatory-vagal hypothesis.

The gustatory-vagal hypothesis proposes that gustatory stimulation elicits a coordinated vagal response manifested as an increase in ingestive behaviors (e.g., sucking) and a decrease in nucleus ambiguus vagal tone measured by decreases in the amplitude of respiratory sinus arrhythmia (RSA). The current study tested the gustatory-vagal hypothesis in a bottle feeding paradigm with 29 clinically stable, high-risk, low-birthweight neonates. The amplitude of respiratory sinus arrhythmia (RSA) was collected before, during, and after bottle feeding. Consistent with the gustatory-vagal hypothesis, RSA decreased during bottle feeding. In a longitudinal subsample of subjects, the pattern of RSA changes during the feeding paradigm was stable across two test sessions.

Electrocardiography↗
PubMed1996

[Improvement of transfusion safety in a health care service through the implementation of a quality program].

The quality policy brings with it an efficient method as well as relevant tools to improve transfusion safety in health care services. This article illustrates the details of the approach through the presentation of a project developed in the East Picardie region throughout several hospitals. It underlines the importance of the choice of a good reference system, of a pertinent method and the necessity of a real project management. Furthermore, the follow-up of the project has enabled us to identify a certain number of success criteria in the steering of the changing process.

France↗
PubMed1996

Changes in vancomycin pharmacokinetics during treatment.

Using data gathered in routine monitoring, the pharmacokinetics of vancomycin during the first 10 days of treatment were compared with the pharmacokinetics after 10 days of treatment in 46 adult patients with normal renal function, ages 17-85 years old (mean +/- SD: 50.8 +/- 17.5). The mean time from initiation of treatment to the first sample determination was 5.5 days, and the mean time to the second determination was 13.4 days. Statistical differences between the two periods were observed for all pharmacokinetic parameters, except for the steady-state distribution volume. After 10 days of treatment, the mean +/- SD of the vancomycin clearance and elimination rate constant decreased from 1.31 +/- 0.82 to 1.13 +/- 0.72 ml/kg/min (p = 0.0044) and from 0.13 +/- 0.08 to 0.10 +/- 0.06 h-1 (p = 0.091), respectively. The half-life (t1/2) increased from 8.01 +/- 6.82 to 10.02 +/- 8.00 h (p = 0.012). The median percentage of the increment of t1/2 was 9.4%. The increase in t1/2 was > 50% in 12 patients and > 100% in nine cases. No association was found between the increment of t1/2 and the cumulative vancomycin dose. Frequent monitoring of serum vancomycin seems indicated, given the risk of decreased elimination during prolonged treatment.

Adolescent↗
PubMed1996

Antinuclear antibodies in dogs with leishmaniasis.

An indirect immunofluorescence method using rat liver as material was developed to determine the incidence of antinuclear antibodies in serum from 44 adult dogs naturally infected with leishmaniasis and, for comparative purposes, in a control group of 30 healthy dogs. Animals in both groups were of different breeds with a similar age distribution. Antinuclear antibodies were not detected in the healthy dogs and only 15.9% of the diseased dogs, 12.0% males and 21.1% females, were positive. The results indicate that in contrast to previously reported figures, the incidence of antinuclear antibodies is low in canine leishmaniasis at least when diagnosis is first made. In order to investigate whether antinuclear antibodies may play a role in the development of the renal damage observed in canine leishmaniasis, the concentrations of serum creatinine were related to the presence of antinuclear antibodies. Only 28.5% of the antinuclear antibodies positive infected dogs showed hypercreatininemia as did 32.4% of the antinuclear antibodies negative infected dogs. Thus, antinuclear antibodies are not significantly cause-effect related to the development of the renal lesions seen in canine leishmaniasis.

Animals↗
PubMed1996

Circulating immune complexes and renal function in canine leishmaniasis.

A third component of complement (C3) capture enzyme-linked immunosorbent assay was used to determine the concentration of IgG circulating immune complexes (CIC) in 91 dogs with naturally acquired leishmania infection and in a control group of 24 healthy dogs. Results were expressed as a percentage of a reference standard. Mean concentrations of CIC were significantly (P < 0.001) higher in leishmania-infected dogs (228.725 +/- 14.283%) than in controls (74.542 +/- 12.614%). An increase in CIC concentration was found in 57.1% of the leishmania-infected dogs. No significant differences could be recorded in CIC levels between males and females in either group. Infected dogs showing hypercreatininemia rendered a statistically significant (P < 0.030) higher serum CIC concentration than sick dogs with normal creatininemia. When hypercreatininemia (> or = 1.30 mg/dl) was used as an indicator for CIC increase, the positive predictive value obtained was 0.9 indicating that renal function impairment was associated with high serum CIC concentration in 90% of the infected dogs.

Animals↗
PubMed1996

Inhibition of apoptotic cell death in B-CLL by interferon gamma correlates with clinical stage.

Apoptosis was evaluated in B cells from 41 patients with B-CLL and 20 healthy aged-matched controls. B cells were cultured with and without gamma-IFN and other cytokines; apoptosis was quantified at regular intervals throughout a 5-day culture period. According to Rai's criteria, 17 patients were classified as good risk, 16 as intermediate and eight as high risk. In vitro, purified B cells from B-CLL patients were evaluated for apoptosis. Maximal apoptosis (44.12%) was observed at day 5 in cells from patients with poor prognosis. The addition of gamma-IFN to the culture media prevented apoptosis in a dose-dependent manner. Maximal inhibition of apoptosis was achieved with 100 IU/ml of gamma-IFN. The degree of inhibition of apoptosis by gamma-IFN was greater in cells from the high-risk group patients than in those from the intermediate and good prognosis group (P < 0.0001). The expression of gamma-IFN receptors in B-CLL cells was evaluated using a MnAb against the extracellular domain of gamma-IFN receptor. After 4 days in culture with gamma-IFN, only cells from the intermediate- and high-risk groups showed an increase in the density of gamma-IFN receptors (P < 0.001). gamma-IFN was not detected in the sera of our study patients. However gamma-IFN was detectable in the media from both normal B cells and B-CLL cells in culture; there was no difference in the amount of gamma-IFN released by cells from the three groups of patients studied. Our results show that in vivo gamma-IFN inhibits apoptosis of B cells from B-CLL patients. The inhibitory effect of gamma-IFN on apoptosis correlates directly with the severity of the disease and this is likely explained by a marked upregulation of gamma-IFN receptors in cells from patients in the high-risk group.

Aged↗
PubMed1996

Autosomal dominant congenital epiphyseal dysplasia limited to the femoral heads.

A father and son with unusual congenital skeletal symptoms, mainly characterized by short stature and epiphyseal dysplasia limited to the femoral heads are described. The comparative analysis with other spondyloepiphyseal dysplasias supports the notion that the syndrome reported here is a distinct autosomal dominant connective tissue disorder.

Adult↗
PubMed1995

Differential expression of DNA topoisomerases in non-small cell lung cancer and normal lung.

UNLABELLED: DNA topoisomerases are ubiquitous nuclear enzymes, and important targets of cancer chemotherapy. Expression of topoisomerase genes is often correlated with in vitro chemosensitivity. We investigated the expression of the topoisomerase genes in normal lung and non-small cell lung cancer. Expression of topoisomerase II-alpha, topoisomerase II-beta, and topoisomerase I genes has been assessed in tumor samples of 60 patients who underwent operation for a non-small cell lung carcinoma, by RNase protection assay, and by immunohistochemistry. The expression of topoisomerase II-alpha gene was either undetectable or very low in normal lung, while most NSCLC expressed readily quantifiable levels of this gene. No alteration of the topoisomerase II-alpha gene was found by Southern blotting in the NSCLC samples. In contrast to topoisomerase II-alpha, topoisomerase II-beta was expressed in most normal as well as in tumor tissue samples, at a similar level. The levels of expression of both topoisomerase II isoforms was lower than that of human lung cancer cell lines. The results of the topoisomerase II mRNA expression were confirmed by immunohistochemistry. Whereas topoisomerase II-alpha staining was mainly limited to the nucleus, staining with topoisomerase II-beta antibody was exclusively observed in nucleoli. Topoisomerase I was localized in the nuclei and expression was mainly limited to tumor cells. By RNase protection, topoisomerase I expression in NSCLC samples was in the range of that of human lung cancer cell lines. The expression of the topoisomerase genes did not seem to be coordinated. In tumor cells, there was a positive association between expression of topoisomerase II-alpha and Ki-67, a marker of cell proliferation, as assessed by immunohistochemistry, but not with topoisomerase II-beta or topoisomerase I. Clinical characteristics of the patients, and their survival did not appear to be correlated to the level of expression of any of the topoisomerase genes, although a trend towards a shorter survival was observed in patients whose tumors expressed relatively high topoisomerase II-alpha mRNA levels. IN CONCLUSION: (1) the two isoforms of topoisomerase II are differentially expressed in normal lung and NSCLC cells; (2) higher topoisomerase II-alpha expression is associated with higher cell proliferation in NSCLC; (3) the expression of topoisomerase II-alpha and topoisomerase I, but not of topoisomerase II-beta, was higher in tumor cells compared to normal lung. Given the differential expression of topoisomerases in normal lung and tumors, research of more potent and specific topoisomerase inhibitors might prove beneficial in non-small cell lung cancer. Immunohistochemistry may be indicated in prospectively investigating the correlation between expression of topoisomerases and results of chemotherapy treatment.

Aged↗
PubMed1995

Parathyroid hormone stimulates electrogenic sodium transport in A6 cells.

The effects of parathyroid hormone (PTH) on sodium homeostasis in the distal tubule are not well defined. Using A6 cells as a model for distal tubular epithelium we measured equivalent short circuit current (leq), as an estimate of net sodium transport. We found that PTH increased leq in a dose-dependent manner. DDA, an agent which inhibits adenylate cyclase, decreased PTH-activated sodium transport, suggesting a role for cAMP elevation in PTH effects. Moreover, addition of Rp-cAMP, an inhibitor of cAMP-dependent protein kinase, partially blocked the PTH-stimulated leq. PTH also elicited a sustained increase in [Ca2+]i in A6 cells. This elevation in [Ca2+]i was abolished by removal of calcium from the extracellular medium, suggesting the involvement of calcium influx pathways. In fact, addition of the calcium channel blocker nitrendipine to PTH-stimulated leq partially blocked PTH-activated sodium transport. Taken together these data demonstrate that PTH stimulates electrogenic sodium transport in A6 cells and that this effect may be mediated through a rise in both intracellular calcium and cellular cAMP.

Adenylyl Cyclase Inhibitors↗
PubMed1995

Evidence that the APOE locus influences rate of disease progression in late onset familial Alzheimer's Disease but is not causative.

An association has been observed in several independent data sets between late onset Alzheimer's Disease (AD) and the APOE locus on chromosome 19. We have examined the genotype in family history positive (FHP) and family history negative (FHN) cases and find a distortion of the APOE allele frequencies in accord with previous studies. However, when we examined the allele distribution of the at-risk siblings of the FHP group we found an excess of the epsilon 4 allele which also differs significantly from historic controls but not from the affected siblings. The age distribution of the affected and unaffected siblings was similar, suggesting that the allelic frequency distortion in the unaffected siblings was not due to their being below the mean age of onset. Lod score linkage analysis, with age dependent onset and non-stringent specification of the genetic parameters, did not suggest linkage to the APOE locus. Furthermore, an analysis of variance of the age of disease free survival suggested that APOE genotype contributes a small fraction of the total variance indicating that the APOE locus is a poor predictor of disease free survival age within late onset families. One explanation for the age dependent association reported by other groups, and our results, is that the APOE locus enhances the rate of progression of the disease process in otherwise predisposed individuals and that variation at this locus is not able in and of itself to cause the disease. We suggest this hypothesis is compatible with the current literature regarding APOE and AD.

Age Factors↗