Search PubMed⌕ Search

Biomedical subjects

M Morales

Publications and source records attributed to M Morales.

At least 109 records · Page 6Linked to original sources
PubMed1998

Start-up and the effect of gaseous ammonia additions on a biofilter for the elimination of toluene vapors.

Biotechnological techniques, including biofilters and biotrickling filters are increasingly used to treat air polluted with VOCs (Volatile Organic Compounds). In this work, the start-up, the effect of the gaseous ammonia addition on the toluene removal rate, and the problems of the heat accumulation on the performance of a laboratory scale biofilter were studied. The packing material was sterilized peat enriched with a mineral medium and inoculated with an adapted consortium (two yeast and five bacteria). Start-up showed a short adaptation period and an increased toluene elimination capacity (EC) up to a maximum of 190 g/m3/h. This was related to increased CO2 outlet concentration and temperature gradients between the packed bed and the inlet (Tm-Tin). These events were associated with the growth of the microbial population. The biofilter EC decreased thereafter, to attain a steady state of 8 g/m3/h. At this point, gaseous ammonia was added. EC increased up to 80 g/m3/h, with simultaneous increases on the CO2 concentration and (Tm-Tin). Two weeks after the ammonia addition, the new steady state was 30 g/m3/h. In a second ammonia addition, the maximum EC attained was 40 g/m3/h, and the biofilter was in steady state at 25 g/m3/h. Carbon, heat, and water balances were made through 88 d of biofilter operation. Emitted CO2 was about 44.5% of the theoretical value relative to the total toluene oxidation, but accumulated carbon was found as biomass, easily biodegradable material, and carbonates. Heat and water balances showed strong variations depending on EC. For 88 d the total metabolic heat was -181.2 x 10(3) Kcal/m3, and water evaporation was found to be 56.5 kg/m3. Evidence of nitrogen limitation, drying, and heterogeneities were found in this study.

Ammonia↗
PubMed1998

Acute ethanol induces c-fos immunoreactivity in GABAergic neurons of the central nucleus of the amygdala.

The central nucleus of the amygdala (CNA) is a component of the brain reward pathway which is believed to represent an anatomical substrate for drugs of abuse. Previous studies have shown that acute ethanol administration induces the expression of c-fos in the CNA of rat brains. We report here, that over 70% of these c-fos immunoreactive neurons are GABAergic. This observation provides the first anatomical evidence that GABAergic neurons of the CNA are responsive to acute ethanol exposure and suggest that the GABAergic system of the CNA is a key neuronal substrate for ethanol actions on the central nervous system.

Amygdala↗
PubMed1998

Changes in the properties of gap junctions during neuronal differentiation of hippocampal progenitor cells.

The cellular mechanisms that regulate progenitor cell lineage elaboration and maturation during embryonic development of the mammalian brain are poorly understood. Conditionally immortalized mouse hippocampal multipotent progenitor cells (MK31 cells) were found to be strongly coupled by gap junctions comprising connexin 43 (Cx43) during early neuronal ontogeny; the presence of this Cx type was confirmed by electrophysiological, molecular biological, and immunocytochemical assays. However, as progenitor cells underwent intermediate stages of neuronal differentiation under the influence of interleukin 7 (IL-7) alone or terminal differentiation after composite exposure to basic fibroblast growth factor, IL-7, and transforming growth factor alpha, coupling strength and the level of Cx43 expression declined. An additional population of junctional channels with distinct properties was detected at an intermediate stage of neuronal differentiation. Reverse transcription-PCR assays detected mRNA encoding Cx40 in IL-7-treated cells and Cx33 after both treatment conditions. Because functional channels in exogenous expression systems are not formed by pairing Cx40 with Cx43 or by pairing Cx33 with itself or additional connexins, these experimental observations raise the possibility that the progressive loss of coupling during differentiation of neural progenitor cells may involve downregulation of Cx43 coupled with potentiation of expression of Cx33 and Cx40. Furthermore, continued expression of Cx43 in differentiating neuroblasts could mediate intercellular communication between neuronal precursor cells and astrocytes by direct signaling via homotypic gap junction channels.

Animals↗
PubMed1998

The prevalence of Dirofilaria immitis in Gran Canaria, Canary Islands, Spain (1994-1996).

Blood samples from 2034 dogs were tested to detect Dirofilaria immitis antigen during three consecutive years (from 1994 to 1996) in Gran Canaria Island, Canary Islands, Spain. The prevalence of heartworm infection was 67.02% in 1994, 58.92% in 1995 and 52.18% in 1996, with a mean prevalence of 58.89%. Heartworm infection was more common in males (56.19%) than in females (43.81 %), in dogs aged between 3 and 6 years old. The distribution of the disease in the different climatic zones was studied. Chronological changes in the dog's prevalence for heartworm infection in the three consecutive years and the role of the epidemiological factors in the changes of the positive rates were evaluated.

Age Distribution↗
PubMed1998

Tamoxifen aziridine binding to cytosolic proteins from human breast specimens is negatively associated with estrogen receptors, progesterone receptors, pS2, and cathepsin-D.

[3H]Tamoxifen Aziridine ([3H]TAZ) is a derivative of the antiestrogen tamoxifen that covalently labels the Estrogen Receptor (ER), and perhaps other uncharacterized proteins. In a previous article we described that [3H]TAZ binds to a cytosolic protein from human uterine tissues that shares some, but not all, the ER properties. Here we have extended these studies to [3H]TAZ binding to cytosol proteins from human breast cancer specimens, and studied its quantitative association with other molecular markers and clinico-pathological variables. Cytosols were obtained in hypotonic buffer containing 20 mM molybdate and protease inhibitors, incubated with [3H]TAZ, and subjected to Sucrose Gradient Analysis (SGA). A [3H]TAZ labeled peak that consistently migrated with the 4S fractions was found in most of the assayed cytosols (range of 0 to 1278 fmol/ mg p.). The 4S peak of [3H]TAZ was partially inhibited by both estrogens and antiestrogens. When [3H]E2 was used instead of [3H]TAZ, only an 8S peak was detected. [3H]TAZ was covalently bound to a protein with an apparent MW of 65 kDa, as determined by SDS-PAGE and fluorography. The mean of [3H]TAZ binding was significantly higher in the subgroups of samples classified as ER-, PR-, pS2- or cathepsin D-, than in the respective positive subgroups (P < 0.01 in all the cases). [3H]TAZ binding was not associated with clinico-pathological variables, except that its mean was significantly larger in tumors larger than 5 cm than in smaller tumors. These results, and those previously reported, suggest that: 1) [3H]TAZ labels a cytosolic protein present in human breast cancers and uterine tissues that does not share all the ER properties, and 2) the [3H]TAZ binding by breast cancer cytosols is negatively associated with markers of estrogenic dependency, and its quantification may provide valuable information on antiestrogen responsiveness of a given tumor.

Biomarkers, Tumor↗
PubMed1998

The central 5-HT3 receptor in CNS disorders.

Among the characterized 5-HT receptors of the central nervous system, the type 3 receptor subtype (5-HT3R) is the only one known to be a ligand-gated ion channel. Its early pharmacological characterization and mapping by radioligand binding autoradiography suggested that this receptor may, among other actions, regulate dopamine release in the nigro-striatal pathway and reduce alcohol consumption in experimental animals while antagonists of this receptor have been reported to treat anxiety disorders. Following the cloning of this receptor in 1991, direct cellular localization was made possible by in situ hybridization and immunohistochemical analysis. Here we summarize our recent efforts showing that 5-HT3R-expressing neurons are mainly GABA containing cells in the rat neocortex, olfactory cortex, hippocampus, and amygdala which also often contain cholecystokinin (CCK) immunoreactivity. These results provide a means to unify some of the initial pharmacological observations.

Animals↗
PubMed1998

Interleukin-2 therapy in HIV infection.

Immune cells secrete a variety of cytokines that have a profoundly significant influence on the immune system. For example, cytokines secreted by T-helper cells have a role in cellular immune response (Th1 cytokines) and in antibody production (Th2 cytokines). Interleukin 2 (IL-2) is used therapeutically for immune modulation, most specifically in cancer therapy. The following report describes the mechanisms of IL-2/IL-2 receptor interaction and summarizes the rationale for using IL-2 in HIV-infected patients and briefly describes recent and ongoing clinical trails using IL-2 in HIV/AIDS disease (intravenous IL-2 therapy and subcutaneous IL-2 therapy). In one study of patients with moderate stage HIV disease, subjects taking a maximum tolerated dose of IL-2 at 12 to 15 MIU/day demonstrated durable increases in CD4 counts and a near normal return in value. Relative to the published reports, low circulating CD4 counts and high HIV viral burden appeared to be independent determinants of a poor response to IL-2. However, aggressive combination therapy with IL-2 and highly active anti-retroviral therapy (HAART)(e.g., ACTG 328) holds promise for an improved immune restorative response even in patients with advanced disease.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Effects of glucagon-like peptide 1 on the kinetics of glycogen synthase a in hepatocytes from normal and diabetic rats.

Glucagon-like peptide 1(7-36)amide (GLP-1) is currently under investigation as a possible tool in the treatment of non-insulin-dependent diabetes mellitus. In addition to enhancing nutrient-stimulated insulin release, the peptide also favors glycogen synthesis and glucose use in liver, muscle, and adipose tissue. GLP-1 also activates glycogen synthase a in hepatocytes from both normal and diabetic rats. In the present study, the kinetic aspects of such an activation were investigated in hepatocytes from normal rats and from animals rendered diabetic induced by injection of streptozotocin, either in the adult age (insulin-dependent diabetes mellitus model) or in days 1 or 5 after birth (non-insulin-dependent diabetes mellitus models). GLP-1 increased, in a dose-dependent manner, glycogen synthase a activity in the hepatocytes from all groups studied. The activation of the enzyme reached a steady state within 1 min exposure to GLP-1, which, at 10(-12) M, caused a half-maximal activation. When comparing fed vs. overnight-starved normal rats, a somewhat lower basal activity of glycogen synthase a in fasted animals (P < 0.05) coincided with a greater relative increment in reaction velocity in response to GLP-1. The basal activity of glycogen synthase a and the relative extent of its inhibition by glucagon or activation by insulin and GLP-1 were modulated by the extracellular concentration of D-glucose. The activation of glycogen synthase a by either insulin or GLP-1 resulted not solely in an increase in maximal velocity but also in a decrease in affinity of the enzyme for uridine diphosphate-glucose; in diabetic animals, the capacity of insulin or GLP-1 to increase the maximal velocity and Michaelis-Menten constant were less marked than in normal rats. In conclusion, this study indicates that the GLP-1-induced activation of glycogen synthase a displays attributes of rapidity, sensitivity, and nutritional dependency that are well suited for both participation in the physiological regulation of enzyme activity and therapeutic purpose.

Animals↗
PubMed1998

Synaptophysin immunoreactivity in the rat pituitary: alterations after 6-hydroxydopamine treatment.

Synaptophysin (SN) is a synaptic-vesicle-associated membrane protein whose presence is indicative of intact, functional synapses. This study examines the presence of SN in pituitary gland innervation after neurotoxin-induced denervation followed by reinnervation. Immunostaining of rat pituitary neurointermediate lobe tissue for SN reveals a pattern of dot-like densities in the intermediate lobe and intensely stained dispersed regions in the neural lobe of normal animals. In rats treated with 6-hydroxydopamine (6-OHDA), a catecholamine neurotoxin, by peripheral injection, there is a significant depletion of the SN immunostaining in the intermediate lobe, as well as a significant reduction of SN immunoreactivity in the neural lobe, in animals studied 1 wk after drug treatment, with computer analysis of the tissue sections. At 3 wk after 6-OHDA, there is a partial recovery of immunoreactivity for SN in the neural lobe in many tissue sections, and the intermediate lobe also contains only relatively sparse staining for the synaptic protein. Computer analysis revealed that at 3 wk after 6-OHDA, both lobes still had reduced SN immunoreactivity, but the difference in levels measured did not achieve statistical significance. These results contrast with the prior finding of significant recovery of immunoreactivity for GAP-43, a growth and regeneration-associated protein, in intermediate lobe innervation of rats treated with the same drug regimen. We suggest that 6-OHDA treatment damages synaptic vesicle integrity in both the intermediate and neural lobes of the pituitary, and that recovery is in progress, but not complete at 3 wk after the drug is administered.

Animals↗
PubMed1998

Peritubular transport of ochratoxin A in rabbit renal proximal tubules.

The transport of the nephrotoxic mycotoxin ochratoxin A across the renal peritubular membrane was examined in suspensions of rabbit renal proximal tubules. Ochratoxin A transport across the peritubular membrane was a high-affinity, low-capacity carrier-mediated process with a Jmax value of 0.12 +/- 0.4 nmol/mg of protein/min and a Km value of 1.4 +/- 0.1 microM. The apparent Michaelis constants for inhibition of [3H]para-aminohippurate (PAH) uptake by ochratoxin A inhibition was 1.5 microM, which is similar to the Km value for ochratoxin A uptake in tubule suspensions and suggests that ochratoxin A could be a substrate for the organic anion pathway. The capacity and affinity for peritubular ochratoxin A transport were 40-fold lower and > 100-fold greater, respectively, than those measured for the peritubular uptake of [3H]PAH in tubule suspensions. A concentration of 2.5 mM PAH, which reduced the uptake of [3H]PAH by 90%, reduced ochratoxin A uptake by only 40% to 50%, whereas probenecid concentrations of 0.6 to 2 mM reduced ochratoxin A accumulation in tubule suspensions up to approximately 80% to 90%. This probenecid-sensitive, PAH-insensitive uptake of ochratoxin A suggested that at least one mediated pathway other than the organic anion transporter was involved in the peritubular uptake of this mycotoxin. A 2 mM concentration of the fatty acid octanoate and 1.5 mM concentration of the nonsteroidal anti-inflammatory agent piroxicam were as effective as probenecid in blocking ochratoxin A uptake. The apparent Ki values for inhibition of ochratoxin A uptake by probenecid, piroxicam and octanoate were 30.5 +/- 7.9, 23.2 +/- 10.4 and 81.5 +/- 8.7 microM, respectively. The ability of octanoic acid to inhibit ochratoxin A transport to the same extent as probenecid and a greater extent than PAH suggests that a separate fatty acid transport pathway may be involved in the accumulation of ochratoxin A by suspensions of rabbit renal proximal tubules.

Animals↗
PubMed1998

DNA quantification as a prognostic factor in gastric adenocarcinoma.

OBJECTIVE: To determine if DNA quantification, studied in cytologic samples obtained by fiberendoscopy, has predictive value in gastric adenocarcinoma. The survival times of patients in whom the tumor was the cause of death were considered variables of interest. STUDY DESIGN: Twenty-nine patients with gastric cancer, diagnosed by cytology, endoscopy and microbiopsy, were selected. The study was done over more than 10 years. Smears were stained with progressive hematoxylin and processed by computer for DNA evaluation by image cytometry. RESULTS: Four different types of histograms that directly relate to tumoral malignancy were obtained. These histograms were characterized by the value of entropy. We established four grades of aggressiveness. Then we obtained two large groups: high and low grade of malignancy. We studied the survival times in both groups and constructed a Kaplan-Meier survival curve for the high grade of malignancy group. We confirmed the results statistically and found that there was a significant relationship, with P < .05. CONCLUSION: The use of DNA quantification by image cytometry is strongly advised in daily surgery as a prognostic indicator of survival time in gastric adenocarcinoma patients.

Adenocarcinoma↗
PubMed1998

[Duodenal duplication].

Cystic duplication of the duodenum is a rare anomaly of the gastrointestinal tract. This is a report of a newborn with a cystic duplication of duodenum diagnosed prenatally. It's relevant the few clinical symptoms of a such big mass. The surgical procedure was excision of the cyst, with a good post operative curse.

Duodenum↗
PubMed1998

[Closed trauma of the pancreas--diagnostic approach].

OBJECTIVE: To review patients who presented lesions of the pancreas following blunt abdominal trauma, in order to determine which elements contributed to or on the contrary delayed the diagnosis. Construction of a diagnostic procedure which could be followed in order to maximize the rapidity and efficency of treatment. DESIGN: Retrospective study. PATIENTS AND METHOD: Patients from 1985 to 1997 having suffered blunt trauma were studied. The lesions of the pancreas were classified according to Lucas. The grounds for indication and the information that the echography, the CT-Scan and the wirsungographie brought to the diagnosis was determined for each patient. Elements which delayed diagnosis were retrospectively evaluated. RESULTS: We treated 11 patients having suffered blunt abdominal trauma resulting in pancreatic damage. 7 patients were operated. Five had emergency laparotomies. Three of these were unable to reveal an existing rupture of the pancreatic duct. CONCLUSIONS: Surgical exploration is difficult and pancreatic lesions are frequently missed. The wirsungography done before or during the operation should, therefore, be more often used as a diagnostic tool.

Abdominal Injuries↗
PubMed1998

Comparative accuracy of glucose monitors.

BACKGROUND: Self-monitoring of blood glucose levels has become an important instrument for the management of patients with diabetes mellitus. Both patients and physicians expect that the monitors will provide reliable results. Numerous environmental, physiologic, and operational factors can affect system performance, yielding results that are inaccurate or unpredictable. METHODS: This study examined the effect of one factor--high altitude--on the performance of seven blood glucose monitoring systems. The following monitors were compared: two One Touch II; two One Touch Basic; two Reflolux II (Accu-Chec in the USA); two Glucometer 3; one Glucometer 2, and one Accutrend Alpha. Double blood glucose level values were compared with a controlled reference laboratory test value, which was unknown to the investigator until the end of the study because the study was double blind. Blood glucose values were obtained using each of the monitors in 200 patients; 150 with diabetes mellitus, and 50 healthy subjects. RESULTS: The One Touch monitors were the only monitors that reported adjusted straight lines (Y = a+bX) that were very similar for all three techniques. In addition, these adjusted straight lines are those closest to the ideal line, Y = X. These same monitors were the only ones that did not reject the null hypothesis Ho: a = 0. The relative deviation index at the 20% level was less than 3.5% for the One Touch II and One Touch Basic monitors; for the rest of the monitors, the index was over 14%. The clinically accepted EGA region was similar for all study monitors. CONCLUSIONS: In conclusion, the One Touch II and One Touch Basic Monitors showed greater accuracy in comparison to the other devices. The evaluation of the clinically acceptable region shows practical reliability for all of the monitors used.

Adolescent↗
PubMed1997

Cortistatin is expressed in a distinct subset of cortical interneurons.

Cortistatin is a presumptive neuropeptide that shares 11 of its 14 amino acids with somatostatin. In contrast to somatostatin, administration of cortistatin into the rat brain ventricles specifically enhances slow wave sleep, apparently by antagonizing the effects of acetylcholine on cortical excitability. Here we show that preprocortistatin mRNA is expressed in a subset of GABAergic cells in the cortex and hippocampus that partially overlap with those containing somatostatin. A significant percentage of cortistatin-positive neurons is also positive for parvalbumin. In contrast, no colocalization was found between cortistatin and calretinin, cholecystokinin, or vasoactive intestinal peptide. During development there is a transient increase in cortistatin-expressing cells in the second postnatal week in all cortical areas and in the dentate gyrus. A transient expression of preprocortistatin mRNA in the hilar region at P16 is paralleled by electrophysiological changes in dentate granule cells. Together, these observations suggest mechanisms by which cortistatin may regulate cortical activity.

Animals↗
PubMed1997

Exendin-4 agonist and exendin(9-39)amide antagonist of the GLP-1(7-36)amide effects in liver and muscle.

The GLP-1 structurally related peptides exendin-4 and exendin(9-39)amide were found to act, in rat liver and skeletal muscle, as agonist and antagonist, respectively, of the GLP-1(7-36)amide effects on glucose metabolism. Thus, like GLP-1(7-36)amide, exendin-4 increased glycogen synthase a activity and glucose incorporation into glycogen in both tissues and also stimulated exogenous D-glucose utilization and oxidation in muscle. These effects of GLP-1(7-36)amide and exendin-4 were inhibited by exendin(9-39)amide. Our findings provide further support to the proposed use of GLP-1, or exendin-4, as a tool in the treatment of diabetes mellitus. Thus, in addition to the well-known insulinotropic action of the peptides, they act both in liver and in muscle in a manner most suitable for restoration of glucose homeostasis, with emphasis on their positive effects upon glycogen synthesis in the two tissues and on the stimulation of exogenous glucose catabolism in muscle.

Animals↗