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Biomedical subjects

R Lozano

Publications and source records attributed to R Lozano.

At least 55 records · Page 3Linked to original sources
PubMed1996

Immune response and in vivo production of cytokines in patients with liver hydatidosis.

Cytokines play an important role in the human immunological response, but the exact role of cytokines in the human immune response against parasites, especially against Echinococcus granulosus, remains unclear. IL-1, IL-2, IL-4 and tumour necrosis factor (TNF) levels in peripheral blood of 21 patients with liver hydatidosis were evaluated before surgical treatment, and the levels of IgA, IgM, IgG, IgE, specific IgE against E. granulosus, C3, C4 and DF complement fractions and CD20, CD3, CD4, CD8 and CD16 cell percentages were also determined, as was the relationship between these variables and cytokine levels. Data from hydatid patients were compared with data obtained from 21 healthy volunteers. Hydatid patients showed increases of IgG, IgE, IgEs and IL-2 (P < 0.01), and decreases of IL-1 and TNF levels (P < 0.001), but these variables (respectively) increased in patients showing cysts in the central area of the liver or with a wide opening of cysts in the biliary tract. The increase of IL-1, IL-2 and IL-4 showed a close relationship with the number, characteristics and above all the location of cysts within the liver itself. IgG and IL-4 levels and also IgG and IgE levels showed a significant correlation (P < 0.05).

Adolescent↗
PubMed1996

Phase II study of paclitaxel therapy for unresectable biliary tree carcinomas.

PURPOSE: To evaluate the efficacy of paclitaxel administered to patients with unresectable adenocarcinomas of the gallbladder and biliary tree over 3 hours every 21 days. PATIENTS AND METHODS: Fifteen patients with unresectable and/or metastatic carcinoma of the gallbladder and bile ducts received intravenous paclitaxel over 3 hours after premedication with dexamethasone, diphenhydramine, and cimetidine. Treatment was repeated every 21 days, and one complete course of therapy was comprised of two such 21-day treatment cycles. The initial dose of paclitaxel was 170 mg/m2, and this was elevated to 200 mg/m2 due to tolerance within the initial patient cohort. RESULTS: All patients were assessable for both toxicity and response: 11 with bile duct cancer and four with gall-bladder carcinoma. Forty-three cycles of therapy were delivered during the trial (median, two), and one patient remains on treatment. No complete or partial responses were noted, although two patients achieved minor responses that lasted 2 and 2+ months, respectively. There were no deaths on this study, and all but one of the patients is still alive. The therapy was well tolerated, and hematologic and mucosal toxic effects were moderate and readily reversible, although significant neuromuscular adverse effects were noted. CONCLUSION: These findings indicate that paclitaxel, administered on this schedule, is tolerable, but is unlikely to have activity in metastatic carcinomas of the biliary tree. It is unclear whether a different regimen of paclitaxel, or another taxane, may have activity in these neoplasms.

Adenocarcinoma↗
PubMed1996

Phase II trial of intravenous flourouracil and subcutaneous interferon alfa-2b for biliary tract cancer.

PURPOSE: To assess the efficacy of systemic intravenous-fluorouracil (5-FU) and subcutaneous recombinant human interferon alfa-2b (rIFN alpha-2b) in patients with measurable cancer of the biliary tree. PATIENTS AND METHODS: Thirty-five patients (25 with cholangiocarcinoma and 10 with gallbladder carcinoma) were registered onto this phase II protocol between 1992 and 1995. Patients received a continuous infusion of 750 mg/m2/d of 5-FU on days 1 through 5 through a centrally placed venous catheter and a subcutaneous injection of 5 MU/m2 of rIFN alpha-2b on days 1, 3, and 5. Treatment cycles were repeated every 14 days; one course of therapy included four treatment cycles. Disease status was assessed every 8 weeks. Dosages were lowered for grade III mucositis. Fourteen patients had prior treatment and, before initiating this therapy, 17 patients required decompression of the biliary tree. RESULTS: Eleven of 32 (34%) assessable patients had a partial response. The median time to disease progression was 9.5 months, and the median survival time 12 months. Grade III to IV toxic effects were granulocytopenia (14%), mucositis (20%), diarrhea (9%), and dermatitis (11%). Grade III to IV asthenia and fatigue were observed in 6% of patients. CONCLUSION: Drug tolerance was better among previously untreated patients. To achieve a complete response, additional chemotherapy or radiotherapy should be considered when liver resection or transplantation is not feasible. However, if these results can be reproduced by other investigators, the regimen should be studied for adjuvant treatment of gallbladder carcinoma incidentally identified in patients undergoing cholecystectomy.

Adult↗
PubMed1996

[Treatment of acute colorectal obstructions by implantation of expandable metal prosthesis].

PURPOSE: To determine the efficacy of colorectal stents implanted through the anus for the treatment of acute intestinal occlusion before elective surgery. MATERIAL AND METHODS: 25 patients (3 females and 22 males) with a mean age of 62.5 years (range: 49-94), were diagnosed of lower intestinal occlusion due to neoplasm. In all cases, an expandable metallic stent was implanted through the anus during the first 24 h. X-ray studies, tumoral staging and surgical preparation were performed in all cases. RESULTS: Implantation of stent was successful in 23 patients (92%). Clinical improvement of intestinal occlusion was observed in 24 hours. Criteria of no-resectability were found in five patients (20%). The remaining patients (18 cases) were treated by tumoral resection and end-to-end anastomosis an average of 8.6 days there after. No complications were observed and the patients were discharged 8.3 days after surgery. CONCLUSION: The implantation of colorectal stents before elective surgery constitutes a good alternative to surgery in the acute lower intestinal occlusion (left colon and rectum-sigmoid emergency).

Aged↗
PubMed1996

Nutritional status of institutionalised elderly in Ecuador.

The nutritional status of 111 elderly men and women aged 60 to 99 years in two institutions in the Ecuadorian Andes was evaluated using dietary, anthropometric and biochemical measurements. Mean daily energy intakes of men and women were 1720 and 1650 kcal, respectively (7.2 and 6.9 MJ), corresponding to 1.5 times the calculated basal metabolic rate (BMR). 6% of subjects had intakes less than 1.2 x BMR and 40% less than 1.5 x BMR. Body mass index (BMI) was below 20 kg/m2 in 21% of subjects; 45% were between 20 and 24. Only one subject had a BMI over 29. Intakes of protein, calcium, iron, riboflavin and vitamin C were satisfactory, in contrast to those of zinc, vitamin A, niacin and thiamin. Using sex- and altitude-specific cutoffs for hemoglobin, anemia was observed in 11% of subjects. Nutritional status, evaluated using biochemical indicators, was satisfactory with respect to riboflavin, vitamin A, vitamin E and copper. 14% of subjects had low serum zinc levels and 17% had serum albumin values below 35 g/L. Low physical activity was associated with low energy intake and low serum albumin levels.

Aged↗
PubMed1995

Rat tail suspension reduces messenger RNA level for growth factors and osteopontin and decreases the osteoblastic differentiation of bone marrow stromal cells.

We previously reported that bone marrow stromal cells produce insulin-like growth factors (IGF-I and -II), and that medium conditioned by marrow stromal cells stimulates osteoblast proliferation in vitro. The present study employed the rat tail-suspension model to unload the hindlimbs. It was designed to test the hypothesis that the development of osteopenia or osteoporosis could be due to a deficit in the osteogenic function of marrow stromal cells. Although tail suspension suppressed body weight during the first 3 days of an 11-day pair-fed study, the overall weight gain recorded by these animals was normal. Nevertheless, bone growth was inhibited by suspension. Similarly, the total adherent marrow stromal cell population harvested from the femurs and tibias was decreased by tail suspension, and only half the normal number of fibroblastic stromal cell colonies grew when they were cultured. The proliferation of alkaline-phosphatase-positive cells in the stroma was also inhibited. Northern hybridization revealed that the messenger RNA level for transforming growth factor-beta 2 and IGF-II in stromal cell was reduced by tail suspension. The production of IGF-II by marrow stromal cells was also decreased. The steady-state level of five different transcript sizes of IGF-I mRNA was altered differentially by tail suspension. Osteopontin mRNA was also reduced in marrow stromal cells from tail-suspended rats compared with the normal rats. These data suggest that skeletal unloading not only alters the mRNA level for growth factors and peptide production, but also affects the proliferation and osteogenic differentiation of marrow stromal cells. These changes may be responsible for the reduced bone formation in osteopenia and osteoporosis.

Animals↗
PubMed1995

Expression of selected osteogenic markers in the fibroblast-like cells of rat marrow stroma.

The fibroblast-like cells in the marrow stromal system were separated from endothelial cells and macrophages by negative selection of magnetic beads. Immunocytochemistry confirmed that these fibroblast-like cells expressed fibronectin and collagen Type III, but not Factor VIII and epithelial membrane antigen (endothelial cell markers) or Mac I (macrophage marker). The fibroblast-like stromal cells (FSC) synthesized the insulin-like growth factors (IGF)-I and -II in amounts equivalent to that produced by unfractionated marrow stromal cells (UMSC); in both, the concentration of IGF-II was 10 times higher than that of IGF-I. Northern analysis revealed that FSC and UMSC expressed identical patterns of mRNAs for IGF-I and transforming growth factor (TGF) -beta 2, for osteopontin, and for procollagen Types I and III (Type I > Type III). Type II procollagen mRNA was not expressed in both cell populations. The TGF-beta 2 gene mRNA was expressed at a lower level by the FSC than UMSC. The pattern of gene expression in these cells is consistent with an osteoprogenitor phenotype. Both FSCs and UMSCs express parathyroid hormone (PTH) and estrogen receptor genes (rtPCR technique). The study provides additional evidence that fibroblast-like marrow stromal cells have an osteoblast signature, and that they are largely responsible for the osteogenic performance of cells in unfractionated marrow.

Animals↗
PubMed1995

Quantitative analysis of fosinopril sodium by capillary zone electrophoresis and liquid chromatography.

A capillary zone electrophoresis (CZE) method was developed for the quantitative analysis of fosinopril sodium. Validation parameters of the CZE method were evaluated and compared to an existing LC method. In terms of precision and sensitivity. LC performance was superior to that of the CZE method for this application. The CZE method achieved better selectivity for several degradants of interest within a much shorter analysis time than did the LC method. Effects of detection wavelength, applied voltage and buffer concentration on optimization of the CZE method are presented. Effects of diluent composition on capillary loading and peak behaviour are also discussed.

Buffers↗
PubMed1995

Cytogenetic analysis of gilthead seabream Sparus aurata (Pisces, Perciformes), a deletion affecting the NOR in a hatchery stock.

We have cytogenetically characterized a hatchery stock of gilthead seabream, Sparus aurata. The study included larvae, juveniles and adults. In S. aurata (diploid chromosome number 2n = 48), a pair of NORs is located at the ends of the short arms of the first submetacentric pair of chromosomes. In this stock we discovered a polymorphism which affects the NORs, and, by means of several cytogenetic and molecular techniques, we demonstrate that this polymorphism is due to the complete deletion of one of the two NORs in a high number of individuals. The significance of these cytogenetic characteristics for this species are discussed since they may be the source of aquaculture problems.

Aging↗
PubMed1995

The EcoRI centromeric satellite DNA of the Sparidae family (Pisces, Perciformes) contains a sequence motive common to other vertebrate centromeric satellite DNAs.

By means of cloning, sequencing, and fluorescence in situ hybridization, we have determined that the EcoRI satellite DNA family is conserved in the 10 sparid species analyzed here. Its conservation, its chromosomal location at the centromere of each chromosome, and its structural features could make this satellite DNA family an important structural and/or functional element of the centromeres of these species. Monomeric units of this satellite DNA have a consensus length of 187 bp. Its sequence is characterized by a high AT content and the presence of short runs of consecutive AT base pairs. These monomeric EcoRI repeats also contain three to four copies, depending on the species, of a short sequence reflecting the repetitive duplication and subsequent divergence of an ancestral 9-bp sequence in this family. This sequence motive is conserved in some parts of the monomeric units of the different species studied at the same positions, and, precisely, surrounding the area in which the curvature of the monomeric molecule is greatest. The 9-bp sequence motive is similar to other direct-repeat sequences of the centromeric satellite DNAs of other vertebrates, including those of amphibians and mammals.

Animals↗
PubMed1994

rDNA site number polymorphism and NOR inactivation in natural populations of Allium schoenoprasum.

Nucleolar-organiser activity has been studied by silver staining and by in situ hybridization with an rDNA probe in two populations of Allium schoenoprasum. One population is monomorphic with NORs and rDNA sites terminal on the short arm of pair 8 in all individuals. The other populations is monomorphic for pair 8 NORs but is also polymorphic for NORs on the long arm of pair 7. All plants in this population carry ribosomal cistrons on both chromosomes of pair 7 but 0, 1 or 2 of these sites can be active in rRNA synthesis. Cis-acting nucleolar-suppression affects the pair 7 locus. We suggest that there has been progressive reduction in the number of NORs during the evolution of A. schoenoprasum.

Allium↗
PubMed1994

Temperature, pH and agitation rate as dissolution test discriminators of zofenopril calcium tablets.

Comparative in vitro dissolution studies were performed on several tablet batches of zofenopril calcium, an ACE inhibitor, to determine if they could be differentiated on the basis of their release rates. The samples included six batches produced at Site 1 and one batch produced at Site 2. Using regular dissolution conditions (USP paddle method at a 50-rpm agitation speed in phosphate buffer, pH 7.5, at 37 degrees C), release rates of all the tablet batches were similar. By independently altering one of the dissolution test parameters, either a lower pH or a slower agitation rate, discrimination between the Site 1 and Site 2 tablets was enhanced. Discrimination was only slightly enhanced when a lower dissolution medium temperature was used. Tablets made from different polymorphs of zofenopril calcium could not be differentiated by their dissolution profiles, even with the more discriminating conditions. The dissolution profiles of certain other zofenopril calcium tablets (including film-coated vs uncoated tablets, and tablets made with micronized vs unmicronized drug particles) were indistinguishable using a 50-rpm agitation rate, but they could be clearly differentiated using a 40-rpm agitation rate.

Captopril↗
PubMed1994

Cloning and characterization of a fish centromeric satellite DNA.

A highly repetitive DNA sequence family from the genome of Sparus aurata has been cloned and characterized. The family is composed of repeat units of 186 bp in length, and it accounts for 2% of the fish genome. Data from Southern blots and in situ hybridization demonstrate that repeating units are tandemly arranged at the centromeres of all the chromosomes in this species. The repetitive sequence is AT rich (67%) and is characterized by short stretches of consecutive AT base pairs and by short direct and inverted repeats. Sequence analysis of six cloned monomers of the family reveals some variation among clones at random positions and also distinguishes two subfamilies of repeats that differ in a highly divergent block of 31 bp. These two subfamilies do not seem to be located in separate domains but occur together in the centromere of each chromosome pair. The presence of this repeat family in the genome of other Sparidae species, some of which are relatively distant from S. aurata, indicates that this repetitive sequence could be an important component of the centromere in this fish family.

Animals↗
PubMed1994

[The epidemiological transition in Latin America].

The changes in health conditions that have occurred in most of the countries of Latin America in the second half of the twentieth century are analyzed. "This paper analyzes the main mechanisms involved in the epidemiologic transition, which are: changes in risk factors, fertility decline and improvements in health care technology." The authors use a mortality profile ratio, obtained by dividing the mortality rate due to infectious and parasitic diseases over the mortality rate due to cardiovascular diseases and neoplasms, to analyze trends in 15 countries. "Three distinct groups can be recognized. Each of them represents a different transitional experience. Such experiences are discussed in detail, including a new 'protracted polarized model' of the epidemiologic transition, which characterizes several Latin American countries. Finally, evidence is provided to illustrate the relationship among economic development, fertility change, and mortality profiles." (SUMMARY IN ENG)

Birth Rate↗