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Biomedical subjects

C Morales

Publications and source records attributed to C Morales.

At least 55 records · Page 3Linked to original sources
PubMed2001

[The activation of A1 adenosine receptors attenuates myocardial stunning in the rabbit].

Hearts exposed to a prolonged period of ischemia (> or = 30 minutes) present smaller infarct size when reperfused in the presence of adenosine. However, when the period of ischemia is shorter, the infarct areas are not very significant, but a postischemic ventricular dysfunction persists. The objective of this study was to determine the effect of adenosine, (administered only during reperfusion) on systolic and diastolic alterations present in postischemic ventricular dysfunction, as well as to determine whether A1 receptors participate in this effect. Isolated isovolumic rabbit hearts were subjected to 15 minutes of global ischemia followed by 30 minutes of reperfusion. Before ischemia and during reperfusion ventricular function was evaluated. In the control group, the left ventricular developed pressure (LVDP) reached 56 +/- 2% of recovery at 30 minutes of reperfusion. The administration of adenosine improved LVDP 75 +/- 3% (P < 0.05 vs. control). However, when adenosine was given in presence of an A1 receptor selective antagonist (DPCPX), LVDP reached 50 +/- 2% (P < 0.05 vs. control). In the control group, left ventricular end diastolic pressure (LVEDP) (diastolic stiffness), increased 293 +/- 4%, at 30 minutes of reperfusion. Only a 15 +/- 8% (P < 0.05 vs. control) increase in LVEDP was observed with adenosine. Reperfusion with adenosine plus DPCPX did not attenuate an increase of 493 +/- 9% (P < 0.05 vs. control) in diastolic stiffness. Adenosine administered from the beginning of reperfusion attenuated both systolic alterations and diastolic stiffness in postischemic dysfunction. This effect was abolished by DPCPX, suggesting an important role for the A1 receptors in adenosine protection.

Adenosine↗
PubMed2001

[Time course of the myocardial infarction in the rabbit].

The histopathologic evolution of myocardial infarct and of areas distant from infarct in rabbit hearts was studied. The left coronary artery of 55 rabbits was ligated, and rabbits were sacrificed at 2, 4, 6, 8, 12, 14, 16, 18, 26, 35 and 56 days post-ligature (n = 5 per group). Two rabbits were used as control and two were sham operated. The hearts were excised, cut in slices and stained with hematoxilin-eosin, Masson's trichrome and picrosirius red. Histological evaluation was semi-quantitative (scale: 0 to +++). At day 2, presence of neutrophils was +++, disappearing completely at day 6. Fibroblast proliferation increased from day 4 to day 14 post-occlusion. Coagulation necrosis in medial myocardium during the first week was +++. Subendocardic myocytolysis was evident from day 2 up to day 56 post-infarction. During the second week, proliferation of lymphocytes and macrophages (+++), granulation tissue formation (+++), and incipient traces of fibrosis that peaked at day 35 were observed. Cicatrization was complete at day 56 (+++). In areas far from infarction (right ventricle and septum), proliferation of fibroblasts was observed at day 2, and perivascular, interstitial and endocardic fibrosis at day 16. In conclusion, myocardial infarction in rabbits, unlike myocardial infarction in human beings, is characterized by early presence of fibroblasts and subendocardic fibrosis, and quick increase and precocious disappearance of neutrophils. An interesting finding was the early proliferation of fibroblasts in normal areas far from infarct.

Animals↗
PubMed2000

Prognostic significance of clinical and angiogenesis-related factors in low-grade oligodendrogliomas.

BACKGROUND: Keeping in mind that oligodendrogliomas have unpredictable biological behavior, the aim of this study is to investigate the prognostic significance of VEGF expression and microvessel density in a homogeneous series of low-grade oligodendrogliomas. METHODS: For this study 36 patients with a low-grade oligodendroglioma treated by surgical resection and radiotherapy were selected. At the time of surgery, in all cases the Karnofsky Performance Scale (KPS) score was more than 70, and the study of the resected tumor disclosed a Ki-67/MIB-1 labeling index (MBI-1 LI) less than 1%. In this homogeneous series, immunohistochemical studies were performed using monoclonal antibodies against VEGF in order to study the expression of this cytokine, and against vascular endothelial CD-34 antigen, in order to identify microvessels. RESULTS: Our results show that in contrast to low-grade astrocytomas, low-grade oligodendrogliomas lacked immunoreactive VEGF. Oligodendrogliomas with low vascular density (less than 20 microvessels per microscopical field, at 200 x) or high vascular density (more than 100 microvessels per field, at 200 x) were identified, but this factor had no influence on the survival rate of patients. On the other hand, analysis of the present series showed that clinical factors, such as age or extent of surgical resection, were not significantly associated with survival. CONCLUSIONS: In contrast to low-grade astrocytomas, the angiogenesis score of low-grade oligodendrogliomas (counting the number of microvessels in tumor tissue) adds little information to help predict tumor behavior.

Antigens, CD34↗
PubMed2000

Prognostic significance of endothelial surface score and MIB-1 labeling index in glioblastoma.

The aim of this study is to investigate the usefulness of a vascular endothelial surface score (VESS) and MIB-1 labeling index (MIB-1 LI), in a defined series of glioblastomas, as biological markers with prognostic significance of survival. Tumor tissue and survival were studied in a series of 38 patients with glioblastoma, previously treated by surgical resection and radiotherapy. For each tumor, immunohistochemical and morphometric studies were performed in order to study MIB-1 LI, and VESS, expressed as the CD-34 immunostained endothelial surface per 1000 tumor cells. The survival for the entire patient population of the series was 48.1+/-14.1 weeks, and the mean VESS for the tumors of the series ranged from 16.7 to 107 microm2 per 1000 tumor cells (mean: 38.7+/-18.2). Factors such as age or MIB-1 LI were not significatively associated with survival, but the median survival for the 18 patients with a VESS less than 35 was 50.7+/-3.7 weeks, versus 45.9+/-2.8 weeks for the 20 patients showing a VESS higher than 36 (p < 0.05). Our present results suggest that tumor VESS, expressed as the CD-34 immunostained endothelial surface per each 1000 tumor cells, may have usefulness, as angiogenic-related factor influencing survival, in patients with glioblastoma.

Adult↗
PubMed2000

Expression of vascular permeability factor in glioblastoma specimens: correlation with tumor vascular endothelial surface and peritumoral edema.

Keeping in mind that the expression of vascular permeability factor (VPF) in astrocytic tumors has been related to tumor angiogenesis and peritumoral edema (PE), the aim of this study is to investigate the correlation between degree of VPF expression by tumor cells, and degree of PE and vascular endothelial surface (VES) in glioblastoma. Tumor tissue and neuroimaging data were studied in a series of 38 patients with glioblastoma. For each tumor, immunohistochemical and morphometric studies were performed in order to obtain a score of VPF expression, and a VES score, expressed as the CD-34 immunostained endothelial surface per each 1000 tumor cells. These parameters were related to the degree of PE. The results show that in glioblastomas there exist a clear correlation between the tumor-cell expression of VPF and VES, but we failed to obtain a significant correlation between degree of PE and degree of VES, or between degree of VPF expression and degree of PE. Our present results suggest that in glioblastomas, tumor angiogenesis is clearly related to the expression of VPF by tumor cells, but factors other than intratumoralpresence of VPF may contribute to the development of PE.

Adult↗
PubMed2000

Antiviral and antiluteolytic activity of recombinant bovine IFN-omega1 obtained from Pichia pastoris.

The gene coding for bovine interferon-omega1 (BoIFN-omega1) was recently cloned and expressed at high levels in the yeast Pichia pastoris. The recombinant BoIFN-omega1 protein shows antiviral activity in different cell lines and has an antiluteolytic effect in cyclic ewes. In this article, we describe a method for purification of BoIFN-omega1 expressed in the methylotrophic yeast P. pastoris and characterization of its activity in vivo. The recombinant protein secreted to the culture medium had low activity because of self-aggregation. BoIFN-omega1 was solubilized using urea and desalting and finally purified by ion exchange chromatography on Q-Sepharose Fast Flow. The yield of purified product was approximately 300 mg/L of fermentation culture, with a specific antiviral activity of 10(8) IU/mg. Its purity was at least 80%. The biologic characterization of purified BoIFN-omega1 was determined by induction of an antiviral state on ewes challenged with 100 lethal doses (LD) of Aujeszky virus and by the extension of the corpus luteum life span and interestrous interval in cyclic cows. Ewes treated with 2 x 106 IU/kg BoIFN-omega1 were protected from Aujeszky virus infection. In cows receiving an intrauterine infusion of 1 mg BoIFN-omega1, equally distributed between the two uterine horns, twice daily from day 14 to day 22 of the experimental estrous cycle, the lifespan of the corpus luteum (25 vs. 19 days) and the interestrous intervals (26 vs. 21 days) were extended when compared with a control group (p < 0.05). We show that recombinant BoIFN-omega1 purified from P. pastoris has high antiviral activity and is an effective antiluteolytic agent in cattle.

Animals↗
PubMed2000

Different patterns of structural luteolysis in the human corpus luteum of menstruation.

Structural luteolysis is a complex process responsible for the elimination of the corpus luteum (CL). The aim of this study was to analyse the luteolytic process of the CL of menstruation. For this, we have morphologically studied 654 ovaries from 340 cycling women. Apoptotic cells were observed almost exclusively during the perimenstrual period and were extremely scarce at advanced stages of involution. Steroidogenic luteal cells surviving to the perimenstrual apoptotic wave underwent characteristic degenerative changes, consisting of intense cytoplasmic vacuolation, expression of macrophage markers and accumulation of lipofuscin pigment, and they persisted for long periods of time. Accumulation of corpora albicantia (CA) was observed in only 25% of a subset of 168 women, whereas 28% showed involuting CL without hyalinization, consisting of clusters of pigment-filled cells, and 46.4% showed ovaries with a mixture of CA and involuting CL without hyalinization or involuting CL with intermediate features. Evolution of the CL towards CA seemed to be related to the presence of a large, blood-filled cavity. The data from this study suggested that different patterns of structural luteolysis exist during CL involution, and that the final fate of the involuting CL is dependent on the presence of a large, central, blood-filled cavity.

Adult↗
PubMed2000

Genetic relatedness of Salmonella isolates from nondomestic birds in Southeastern United States.

Salmonella infections have been implicated in large-scale die-offs of wild birds in the United States. Although we know quite a bit about the epidemiology of Salmonella infection among domestic fowl, we know little about the incidence, epidemiology, and genetic relatedness of salmonellae in nondomestic birds. To gain further insight into salmonellae in these hosts, 22 Salmonella isolates from diseased nondomestic birds were screened for the presence of virulence and antibiotic resistance-associated genes and compared genetically using pulsed-field gel electrophoresis (PFGE) and random amplified polymorphic DNA analysis. Of the 22 Salmonella isolates examined, 15 were positive for the invasion gene invA and the virulence plasmid-associated genes spvC and pef. Most (15 of 22) were generally sensitive to antibiotics. However, two Salmonella isolates from pet birds were identified as Salmonella enterica serovar Typhimurium DT104. Despite the general susceptibility of these Salmonella isolates to most antimicrobial agents, antibiotic resistance-associated genes intI1, merA, and aadA1 were identified in a number of these isolates. Five distinct XbaI and nine distinct BlnI DNA patterns were observed for the 22 Salmonella isolates typed by PFGE. PFGE analysis determined that Salmonella isolates from passerines in Georgia and Wyoming were genetically related.

Animals↗
PubMed2000

Progesterone on an oestrogen background enhances prolactin-induced apoptosis in regressing corpora lutea in the cyclic rat: possible involvement of luteal endothelial cell progesterone receptors.

Preovulatory surges of both prolactin (PRL) and progesterone have been suggested to be necessary for the induction of apoptosis in the regressing corpus luteum of the cyclic rat. The aim of these experiments was to study whether the administration of PRL and/or progesterone on the morning of pro-oestrus reproduces the regressive changes that happen in the cyclic corpus luteum (CL) during the transition from pro-oestrus to oestrus, and to analyse the temporal relationships between two characteristic features of structural luteolysis (luteal cell apoptosis and accumulation of macrophages). Cyclic rats (treated at 0900 h with an LHRH antagonist to block LH secretion) were injected at 1000 h with PRL and progesterone and killed at 0, 30, 60, 90 and 180 min after treatment. The number of apoptotic cells increased progressively from 60 min after treatment onward in hormone-treated rats, whereas the number of macrophages did not change throughout the period of time considered. Rats injected with PRL plus progesterone showed significantly greater numbers of apoptotic cells than those injected with PRL alone. The luteolytic effects of progesterone were in keeping with the presence of luteal endothelial cells showing progesterone receptor (PR) immunoreactivity in pro-oestrus. Treatment of rats during dioestrus and pro-oestrus with the specific antioestrogens LY117018 and RU58668 decreased the luteolytic effects of PRL and progesterone and the number of luteal endothelial cells immunostained for PR. These results strongly suggest that the preovulatory PRL surge and the preovulatory increase in progesterone together trigger structural regression of the corpus luteum. This seems to be dependent on oestrogen-driven cyclic changes in PRs in luteal endothelial cells.

Animals↗
PubMed1999

Notochord involvement in experimental esophageal atresia.

Esophageal atresia (EA) is often accompanied by vertebral defects and other anomalies. The adriamycin rat model of EA has disclosed the embryology of the malformation and shown that the vertebrae and notochord are also abnormal. This study describes the nature of notochord malformations in rat embryos exposed to adriamycin. Time-mated rats received either 1.75 mg/kg adriamycin or vehicle i.p. on gestational days (E) 6 to 9; E-12, E-12.5, and E-13 embryos were harvested, embedded in paraffin, and serially sectioned at 3 microm in transverse plane from the head to the stomach for subsequent PAS staining. The findings in both groups were compared at the three endpoints. Control embryos had neither tracheoesophageal nor notochord malformations. On day 12, only 11/36 adriamycin embryos were normal; 7/36 had abnormal notochords, 11/36 had EA, and 7/36 had both. The corresponding figures for 12.5 days were 12/27, 0/27, 7/27, and 8/27 and those for the day 13 7/23, 5/23, 3/23, and 8/23. The malformed notochords were thickened, bifurcated, or trifurcated in the sagittal plane. The simultaneous presence of notochord and esophageal malformations suggests a direct link between both defects, but our observation of isolated occurrence of both shows that they reflect two expressions of the profound disturbance of embryonic para-axial organization responsible for the cluster of malformations rather than a cause-effect association.

Animals↗
PubMed1999

Existence of junction-like structures in large B-cell non-Hodgkin's lymphomas. An ultrastructural study.

The purpose of this work is to study the presence of cell junction-like structures in large B-cell lymphomas. The ultrastructural study, based on 20 cases of this entity proved by immunohistochemistry and flow cytometry, demonstrated four types of junction-like devices easily found between tumor cells. Several explanations are offered about the possible nature of such structures, including the possibility of them being the result of adhesion phenomena. It should also be emphasized that they can potentially complicate the differential diagnosis of those neoplasms. We should, therefore, be careful in rejecting an ultrastructural diagnosis of large B-cell lymphoma based only on the presence of junction-like structures.

Biomarkers, Tumor↗
PubMed1999

Datura metel: in vitro production of tropane alkaloids.

Hairy root lines of Datura metel were established following infection of aseptic stem segments with Agrobacterium rhizogenes strain A4 and cultured in hormone-free B5 solid medium. The growth and production of hyoscyamine and scopolamine (mg/g dry wt.) of these root cultures was encouraged by using B5 liquid medium with half-strength salts. In these culture conditions, the capacity of the highest productive root line 25 to excrete scopolamine into the culture medium rose from 8.7% to 70% when the permeabilizing agent Tween 20 was added for 24 h to the medium, after 2 and 4 weeks of culture. Using an airlift bioreactor (41) with modifications in order to increase root anchorage, the Tween 20 treatment encouraged both growth and alkaloid productivity of cultured root line 25. After 4 weeks their biomass yield was 2.3 mg/l/day and 0.84 mg/l/day of scopolamine was produced (70% extracellular). The scopolamine released into the culture medium was separated with an Amberlite XAD-2 column located in the media exit.

Alkaloids↗
PubMed1999

Immunolocalization of glutaredoxin in the human corpus luteum.

Glutaredoxin (Grx) is a small protein with oxidoreductase activity which is involved in the cellular defence against oxidative stress. Corpus luteum (CL) regression has been related to the generation of reactive oxygen species (ROS). We have studied the presence of glutaredoxin in the human ovary during the ovulatory cycle using polyclonal antibodies developed against recombinant human Grx. Immunostaining was only detected between days 15 and 23 of the cycle and was localized exclusively in the corpus luteum. Grx-positive cells corresponded to granulosa-derived luteal cells (GLC) whereas the remaining luteal cell types were not immunostained. In general, Grx immunoreactivity was parallel to the functional activity of the CL. Most GLC were immunostained on days 15-16 of the cycle, whereas on days 17-19 immunoreaction was found mainly at the inner and outer aspects of the granulosa lutein layer (GLL). After this stage only isolated GLC showed Grx immunoreactivity and no reaction was found from day 23 of the cycle onward. In two CL of pregnancy that were also studied, isolated GLC showed Grx immunoreactivity. Loss of Grx immunoreactivity was coincident with the appearance of morphological signs of structural luteolysis, such as shrinkage of the GLL and the presence of apoptotic cells. These data suggest that Grx, as a cellular antioxidant, plays an important role in the mechanisms of human CL development.

Apoptosis↗
PubMed1999

A quantitative study of changes in the human corpus luteum microvasculature during the menstrual cycle.

Endothelial cells are the most abundant cell type in the corpus luteum (CL), and changes in blood vessels have been proposed to play a pivotal role in CL regression. We have studied quantitatively the changes in the human granulosa-luteal microvasculature in CL of various ages: young (Days 17-19 of the cycle), mature (Days 20-24), old (Days 25-27), early regressing (follicular phase of the following cycle), and late regressing (luteal phase of the following cycle). Blood vessels were identified by immunohistochemical staining for the endothelial cell marker CD34. Because of the anisotropy of blood vessels, both vertical and transverse sections of the granulosa-lutein layer (GLL) were used to estimate relative (volume, surface, and length densities) and absolute (mean cross-sectional area) vascular variables. Full luteinization from young to mature CL was accompanied by a 61% increase in the mean cross-sectional area of vascular profiles and a 52% increase in the mean volume of granulosa-lutein cells, as an estimator of changes in the volume of the GLL. In old and early regressing CL, there was a progressive increase in relative structural vascular variables, due to the shrinkage of the GLL, whereas the mean cross-sectional area of capillaries showed a 53% decrease from mature to old CL. Finally, in late regressing CL, there was a decrease in most relative structural variables, in spite of the increasingly shrunken GLL. The decrease in the capillary diameter found at the late luteal phase most likely leads to a decreased blood flow, and early changes in blood vessels could initiate and/or accelerate CL regression.

Corpus Luteum↗
PubMed1999

Precision, accuracy and linearity of radiometer EML 105 whole blood metabolite biosensors.

The analytical performance of a new, whole blood glucose and lactate electrode system (EML 105 analyser. Radiometer Medical A/S. Copenhagen, Denmark) was evaluated. Between-day coefficients of variation were < or = 1.9% and < or = 3.1% for glucose and lactate, respectively. Recoveries of glucose were 100 +/- 10% using either aqueous or protein-based standards. Recoveries of lactate depended on the matrix, being underestimated in aqueous standards (approximately -10%) and 95-100% in standards containing 40 g/L albumin at lactate concentrations of 15 and 30 mmol/L. However, recoveries were high (up to 180%) at low lactate concentrations in protein-based standards. Carry-over, investigated according to National Clinical Chemistry Laboratory Standards EP10-T2, was negligible (alpha = 0.01). Glucose and lactate biosensors equipped with new membranes were linear up to 60 and 30 mmol/L, respectively. However, linearity fell upon daily use with increasing membrane lifetime. We conclude that the Radiometer metabolite biosensor results are reproducible and do not suffer from specimen-related carry-over. However, lactate recovery depends on the protein content and the lactate concentration.

Biosensing Techniques↗
PubMed1999

Maximal response plateau to methacholine as a reliable index for reducing inhaled budesonide in moderate asthma.

Although some studies suggest that asthma deteriorates after reducing inhaled steroids, results of long-term studies indicate that this might not be true for all patients. The aim of this study was to determine the utility of the detection of a plateau on the concentration-response curves to inhaled methacholine as a marker for safely reducing the dose of inhaled budesonide in asthmatic patients who are well-controlled with a moderately high dose of this inhaled steroid. A total of 46 patients with moderate asthma, well-controlled for at least 6 months by treatment with 800 microg budesonide daily, were included in the study. Subjects were treated for a 2-week run-in period with their usual dose of budesonide. At the end of the run-in, all subjects were challenged with methacholine (0.095-200 mg x mL(-1)). Plateau responses, median effective concentration values, slopes and provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (FEV1) values were measured. For the subsequent 12 weeks, patients were treated in an open design with budesonide at a reduced dose (200 microg once daily), and were asked to record their peak expiratory flow (PEF) in the morning and in the evening. In addition, asthma symptoms and use of rescue terbutaline were recorded in diaries. Plateaus were present in 24 patients, whereas 22 subjects showed concentration-response curves without evidence of a plateau. Ten patients in the nonplateau group deteriorated after reducing inhaled budesonide, compared to one patient in the plateau group (p = 0.002). In the nonplateau group, FEV1 decreased from a baseline value of 3.28+/-0.19 L to 2.94+/-0.20 L at week 12 (p<0.0001). Likewise, morning PEF decreased from 419+/-19 L x min(-1) at baseline to 394+/-19 L x min(-1) at week 12 (p = 0.02). By contrast, these variables remained unchanged in the plateau group. In conclusion, in asthmatic patients, well-controlled with a moderately high dose of budesonide, the detection of a plateau on the concentration-response curve to inhaled methacholine may be used as a marker for safely reducing the corticosteroid dose.

Administration, Inhalation↗