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Biomedical subjects

M Morales

Publications and source records attributed to M Morales.

At least 91 records · Page 5Linked to original sources
PubMed2000

[Nodular lymphangitis caused by Nocardia asteroides].

BACKGROUND: Nocardia species are typically found in soil and decaying organic matter. The lymphocutaneous type or nodular lymphangitis is unusual. This is acquired in most of cases by a traumatic inoculation through the skin of a person who is immunocompetent, and is generally caused by Nocardia brasiliensis. METHODS: We report two cases of nodular lymphangitis caused by Nocardia asteroides, that have been admitted in our hospital during one year period. RESULTS: The two healthy persons of 26 and 56 years old suffered from a cutaneous puncture in their arms caused by a plant's pricke while they were gardening. The symptoms they showed at the area of the puncture were ulcerative lesion and inflammatory nodules through the lymphatic tract that were abscessed. There were not any systemic involvement. Cultures of the purulent drainage and skin biopsy revealed Nocardia asteroides. Treatment with oral trimethoprim-sulfamethoxazole for 8 weeks and surgical debridement resulted in a cure without relapse. CONCLUSION: Nodular lymphangitis has specific symptoms and clinical signs. A detailed clinical and occupational history, accompanied by microbiology identification at the cutaneous biopsy and exudation, should allow specific treatment. Trimethoprim-sulfamethoxazole continues being the selected antibiotic.

Adult↗
PubMed1999

A selective group of dopaminergic neurons express Nurr1 in the adult mouse brain.

Nurr1, an orphan receptor of the nuclear receptor superfamily, is widely expressed in the central nervous system (CNS) including brain regions where dopaminergic neurons are abundant. Recent analyses of Nurr1 null mutant mice have shown that Nurr1 is essential for the development and survival of midbrain dopaminergic neurons. However, other dopaminergic neuronal populations do not seem to be affected by ablation of the Nurr1 gene. The purpose of the present study was to investigate the degree of co-existence of Nurr1 mRNA and tyrosine hydroxylase (TH) immunoreactivity in the brain of adult mice to better characterize the selective effects of Nurr1 on catecholaminergic neurons. Our results indicate that the majority of TH-immunoreactive neurons in the substantia nigra (SN; 96%), ventral tegmental area (VTA; 95%), retrorubral field (91%), olfactory bulb (85%), linear nucleus raphe (91%) and central grey (61%) express Nurr1. In contrast, dopaminergic cells of the paraventricular and periventricular hypothalamic nucleus showed only a few Nurr1/TH double labeled neurons, while TH-immunoreactive neurons in the arcuate nucleus and zona incerta did not express Nurr1 mRNA. Nurr1 expression was also excluded from (nor)adrenergic neurons of the brainstem. In conclusion, Nurr1 transcripts were not found in all CNS catecholaminergic neurons. Nurr1 expression was confined to periglomerular and midbrain dopaminergic neurons. These results suggest that within the adult mouse brain, Nurr1 may participate in dopaminergic functions of the olfactory bulb and midbrain.

Animals↗
PubMed1999

Functional characterization of the human platelet glycoprotein V gene promoter: A specific marker of late megakaryocytic differentiation.

Glycoprotein V (GPV), a subunit of the platelet GPIb-V-IX receptor for von Willebrand factor and thrombin, is specifically found in platelets and mature megakaryocytes. Studies of the GPV gene can therefore provide insight into the mechanisms governing megakaryocyte differentiation. The human GPV promoter was isolated, and elements important for its tissue specific transcriptional activity were localized using systematic DNase I protection and reporter deletion assays. A -1413/+25 fragment inserted into a luciferase reporter construct displayed promoter activity in Dami and HEL but not in K562, HL60, or HeLa cells. Progressive 5' to 3' deletion showed a putative enhancer region in the -1413/-903 segment that contained closely spaced GATA and Ets sites protected from DNase I digestion in Dami extracts. Regions similar to a GPIIb gene repressor were found at -816 and -610, with the first exhibiting repressor activity in Dami and HEL cells and the second protected from DNAse I. Deletions from -362 to -103, an area containing protected sites for Sp1, STAT, and GATA, induced a progressive decrease in activity. The -103/+1 fragment, bearing a proximal Ets footprinted site and a GATA/Ets tandem footprint, displayed 75% activity relative to the full-length promoter and retained cell specificity. In summary, this work defines several regions of the GPV gene promoter important for its activity. It contains megakaryocyte-specific signals, including erythro-megakaryocytic GATA, and Ets cis-acting elements, GPIIb-like repressor domains, and binding sites for ubiquitous factors such as Sp1, ETF, and STAT.

Base Sequence↗
PubMed1999

Chemokine pattern in relation to disease state in human immunodeficiency virus-infected children.

Although beta chemokines can block human immunodeficiency virus (HIV) entry into target cells, their role in HIV disease progression is controversial. To determine the association of RANTES with HIV disease state, we examined constitutive mRNA expression by reverse-transcribed polymerase chain reaction (RT-PCR) in peripheral blood mononuclear cells (PBMCs) and induction of RANTES secretion by enzyme-linked immunosorbent assay (ELISA) in anti-CD3 monoclonal antibody (MAb)-stimulated cultures of PBMCs, and in CD4+ and CD8+ T cell subsets of 17 HIV-infected children. In comparison with uninfected subjects, PBMCs of HIV-infected children were deficient in both constitutive RANTES mRNA expression as well as in stimulus-induced RANTES production. Children in clinical category C were found to be more deficient than children in clinical category A. Expression of RANTES mRNA in PMBCs was inversely correlated with plasma virus load and correlated directly with CD4+ T cell counts. In T cell subsets, RANTES production was equivalent between CD4+ and CD8+ T cells in patients and controls but CD8+ T cells of children in clinical category A produced higher RANTES levels than those of children in clinical category C. The beta-chemokine RANTES may play an important role in slowing clinical disease progression in HIV-infected children.

Adolescent↗
PubMed1999

Modulation of serotonin 5-HT3 receptor expression in injured adult rat spinal cord motoneurons.

The effects of sciatic nerve lesions on the expression of serotonin 5-HT3 receptor (5-HT3R) alpha subunit in motoneurons of the spinal cord was investigated by semi-quantitative immunohistochemistry. Following sciatic nerve crush, a significant reduction in density of staining in motoneurons was observed in longitudinal sections of the ventral horn at 3 and 15 days on the lesioned side when compared to the contralateral side (p<0.01). At 30 days after crush, after completion of sciatic nerve regeneration and reinnervation of peripheral targets, intensity of staining had returned to normal. Conversely, after sciatic nerve cut, a lesion that does not allow for target reinnervation, highly significant reductions were observed at 3, 15, 30 and 45 days. These results suggest a role for functional contacts with muscular targets in the maintenance of 5-HT3R expression in spinal motoneurons.

Animals↗
PubMed1999

Presynaptic calcium-channel currents in normal and csp mutant Drosophila peptidergic terminals.

The study of regulated vesicle exocytosis, which underlies neurotransmitter and neuropeptide release, has benefited from a convergence of several independent approaches. These include the use of genetically tractable organisms and model preparations that allow a direct characterization of presynaptic ionic currents. Aiming for a comprehensive analysis of release, we had already developed a Drosophila preparation in which electrophysiological recordings from peptidergic terminals are feasible. Here, we report on the characterization of the Ca2+-channel currents present in these terminals. With Ba2+ as the charge carrier, the presynaptic membrane expresses a current type with high-activation threshold and little inactivation. This current is blocked by verapamil and diltiazem at micromolar concentrations, it is relatively insensitive to nifedipine and completely resistant to non-L-type Ca2+-channel antagonists. As a comparison, we also analysed the pharmacology of high-threshold Ba+2 currents on muscle fibres. A high-activation threshold Ca2+-channel current is also present in muscle fibres, albeit with a distinct pharmacological profile. Thus, peptidergic terminals and muscle fibres exhibit different subtypes of voltage-gated Ca2+ channels. The putative role of cysteine string protein (CSP) as a neuronal Ca2+-channel modulator was tested by examining the peptidergic presynaptic current in csp null mutants. We show that CSP is expressed in peptidergic boutons and abolished in the mutant. Direct recordings, under conditions that inhibit calcium influx into glutamatergic terminals, show that Ca2+-currents in peptidergic csp terminals are entirely normal. This result indicates that CSP is not a generic Ca2+-channel modulator and it might perform different functions in fast versus slow forms of release.

Animals↗
PubMed1999

Transplantation of fetal kidney tissue reduces cerebral infarction induced by middle cerebral artery ligation.

The authors, and others, have recently reported that intracerebral administration of glial cell line-derived neurotrophic factor (GDNF) or osteogenic protein-1 protects against ischemia-induced injury in the cerebral cortex of adult rats. Because these trophic factors are highly expressed in the fetal, but not adult, kidney cortex, the possibility that transplantation of fetal kidney tissue could serve as a cellular reservoir for such molecules and protect against ischemic injury in cerebral cortex was examined. Fetal kidneys obtained from rat embryos at gestational day 16, and adult kidney cortex, were dissected and cut into small pieces. Adult male Sprague-Dawley rats were anesthetized with chloral hydrate and placed in a stereotactic apparatus. Kidney tissues were transplanted into three cortical areas adjacent to the right middle cerebral artery (MCA). Thirty minutes after grafting, the right MCA was transiently ligated for 90 minutes. Twenty-four hours after the onset of reperfusion, animals were evaluated behaviorally. It was found that the stroke animals that received adult kidney transplantation developed motor imbalance. However, animals that received fetal kidney grafts showed significant behavioral improvement. Animals were later sacrificed and brains were removed for triphenyltetrazolium chloride staining, Pax-2 immunostaining, and GDNF mRNA expression. It was noted that transplantation of fetal kidney but not adult kidney tissue greatly reduced the volume of infarction in the cerebral cortex. Fetal kidney grafts showed Pax-2 immunoreactivity and GDNF mRNA in the host cerebral cortex. In contrast, GDNF mRNA expression was not found in the adult kidney grafts. Taken together, our data indicate that fetal kidney transplantation reduces ischemia/reperfusion-induced cortical infarction and behavioral deficits in adult rats, and that such tissue grafts could serve as an unique cellular reservoir for trophic factor application to the brain.

Animals↗
PubMed1999

Possible participation of an islet B-cell calcium-sensing receptor in insulin release.

The calcium-sensing receptor gene was recently shown to be expressed in rat pancreatic islets and purified islet B-cells. In this study, we investigated the possible role of this receptor in the regulation of insulin release from isolated rat pancreatic islets. Poly-L-arginine (0.2-0.3 microM) and poly-L-lysine (0.03-0.1 microM) increased insulin output evoked by D-glucose (8.3 mM). This positive effect faded out at higher concentrations of the basic peptides. Likewise, the release of insulin evoked by 8.3 mM D-glucose was significantly lower at high (1.0 mM) than low (0.05-0.1 mM) concentrations of neomycin. The insulinotropic action of Ba2+ in Ca2+-deprived islets was potentiated in rats pretreated with pertussis toxin. However, Gd3+ inhibited insulin release evoked by D-glucose in islets prepared from normal rats or animals pretreated with pertussis toxin and incubated in the absence or presence of either theophylline or forskolin. Gd3+ (0.3 mM) failed to affect effluent radioactivity from islets prelabeled with myo-[2-3H]inositol and cyclic AMP net production in islets incubated in the absence or presence of forskolin. Gd3+ decreased, however, 45Ca efflux from prelabeled islets perifused in the absence or presence of extracellular Ca2+. It is speculated that a negative insulinotropic action mediated by the calcium-sensing receptor, and possibly attributable to a fall in cytosolic Ca2+ concentration, may prevent excessive insulin secretion in pathological situations of hypercalcemia.

Animals↗
PubMed1999

Massive fetomaternal hemorrhage: how long should children with good evolution be controlled? A case report.

We report on a term infant with a severe fetomaternal hemorrhage that caused a serious anemia that was surmounted after several transfusions. After the initial complications, such as persistent pulmonary circulation, severe anemia and thrombocytopenia, the outcome was good. We discuss the importance of a long-term follow-up of affected children, as well as their mothers. No clear parameters for a real prognosis are available. A follow-up is needed in order to detect possible complications in neurological development.

Adult↗
PubMed1999

Ochratoxin A secretion in primary cultures of rabbit renal proximal tubule cells.

Primary cultures of rabbit renal proximal tubule cells grown under improved culture conditions were used to study the transepithelial transport of the nephrotoxic mycotoxin ochratoxin A. The basal-to-apical transepithelial flux, i.e., secretion, of this fluorescence organic acid was measured in primary cultures of rabbit renal proximal tubule cells. The basal-to-apical flux of ochratoxin A increased with time and reached a steady state after 12 h. On the other hand, the apical-to-basal flux, i.e., reabsorption, of ochratoxin A was minimal over time. The secretory flux of ochratoxin A was as much as eightfold greater than the reabsorptive flux, indicating that net secretion is the primary mechanism for ochratoxin A clearance by the proximal tubule. The kinetic analysis of ochratoxin A flux revealed secretion to be a saturable and very high-affinity process with an apparent K50 of 0.33 +/- 0.21 mM. A saturating concentration of the prototypical organic anion substrate para-aminohippurate (PAH) reduced ochratoxin A secretion by approximately 75%. The kinetic analysis of PAH inhibition of ochratoxin A secretion revealed an IC50 of 195 mM, which is similar to the IC50 for PAH inhibition of peritubular ochratoxin A uptake in tubule suspensions and the Km, values for peritubular PAH uptake. The organic anions probenecid, octanoate, and alpha-ketoglutarate reduced ochratoxin A excretion to the same degree as PAH, whereas the amino acid phenylalanine had a minimal effect on ochratoxin A secretion. Thus, collectively, these observations indicate that the secretion of ochratoxin A in primary cultures of rabbit renal proximal tubules is limited to the organic anion secretory pathway. The high affinity measured for the basal-to-apical flux of ochratoxin A suggests that at concentrations typical of naturally occurring exposures, transepithelial secretion by the organic anion transport pathway represents a significant avenue for excretion of this mycotoxin by the renal proximal tubule.

Animals↗
PubMed1999

[Pregnancy and scuba diving: what precautions?].

Scuba diving is a leisure activity increasingly popular amongst women. Many women are concerned about the risks associated with diving and a known or planned pregnancy. In order to advise these young women, we have reviewed the literature concerning women and diving as well as animal studies on the subject. The different international federations and the Undersea and Hyperbaric Medical Society advise against scuba diving for pregnant women or those planning a pregnancy, but no randomized trials or trials provide a solid scientific basis. The fetal circulation is characterized by the exclusion of the pulmonary circulation by 2 right to left shunts. As the lung appears to act as a filter against the progression of micro-bubbles to the main circulation, the fetus may be therefore particularly exposed to gas emboli. However, the placenta could play this role in certain animal species. Nitrox diving appears to be particularly promising, but studies on the subject are still insufficient to recommend it for pregnant women.

Accidents↗
PubMed1999

Effect of cholinergic agonists on muscular tonus of the lizard small intestine and esophagus.

The underlying mechanisms of acetylcholine-induced intestinal relaxation in the lizard Liolaemus tenuis tenuis are still unknown. By using a classical model of intestinal recording of isometric contraction and relaxation in conjunction with specific pharmacological tools, this article studies the possible influence of EDRF/NO and nicotinic ganglionar receptors on the Ach-induced relaxation in an effort to elucidate the probable mechanisms involved in ACh effect. It was observed that the relaxation of the lizard intestine elicited by ACh (10(-7) - 4 x 10(-4) M) was not affected by hexametonium (5 x 10(-4) M) or tetrodotoxin (10(-6) M). Nicotine (10(-7) to 10(-4) M) induced relaxation was significantly antagonized by hexametonium; however, it was not influenced by tetrodotoxin. These results allow us to discard a neuronal pathway in cholinergic-induced relaxation, suggesting a more direct cholinergic effect on the smooth muscle, perhaps mediated by an unknown substance released by some specialized tissue. N-nitro-L-arginine, used to block NO-synthase and NO production, induced no changes in ACh-induced relaxation. Methylene blue, a soluble guanylate cyclase inhibitor, induced no changes in ACh-induced relaxation. These results allow us to discard a probable role of EDRF/nitric oxide in the ACh-induced relaxation of lizard small intestine, providing evidence that this mechanism could be different from that reported in other species.

Animals↗
PubMed1999

Left internal mammary artery to innominate vein fistula complicating pacemaker insertion. Treatment with endovascular transarterial coil embolization.

Arteriovenous fistula (AVF) is rarely encountered as a complication of pacemaker insertion. Percutaneous angiographic therapy of such iatrogenic fistulas can be both safe and effective, leading to important reductions in costs. A 60-year-old woman was admitted to the hospital four weeks after left subclavian pacemaker insertion complaining of signs of congestive heart failure. A loud continuous machinery bruit was heard over the left upper chest. An arteriogram revealed a false aneurysm from the LIMA, 6 mm in-diameter, with formation of an AVF between the LIMA and the left innominate vein. Embolization of the LIMA was carried out using seven Platinum coils at the level of the AVF and the false aneurysm was embolized with 3 controlled-release IDC coils. The complete occlusion of the fistula was achieved and the distal LIMA persisted patent due to the opening of collateral vessels from the intercostal arteries. AVF between the subclavian artery or its branches and the subclavian or innominate veins have been reported to be congenital, traumatic and iatrogenic (associated to central venous access to hemodynamic monitoring, dialysis, and very infrequently to pacemaker insertion) but the internal mammary arteries are only rarely involved. The course of AVF is undefined, but generally, surgical or percutaneous embolization is warranted because of the potential appearance of a great number of complications. Surgical repair is associated with significant morbidity and mortality. Whenever possible, percutaneous nonsurgical occlusion of the AVF with coil embolization is the procedure of choice, because of its high success rate and low morbidity.

Aneurysm, False↗
PubMed1999

DNA quantification as a prognostic factor in colorectal adenocarcinoma.

OBJECTIVE: To determine if DNA quantification, studied in cytologic samples obtained by fiberendoscopy, has predictive value in colorectal adenocarcinoma. STUDY DESIGN: Thirty patients with colorectal cancer diagnosed by cytology, endoscopy and microbiopsy, were selected. The study covered > 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 related to malignancy were obtained. These histograms were characterized by the value of entropy, and we established four grades of aggressiveness. Finally, we obtained two large groups: high and low grade of malignancy. We studied the survival times in both groups and used a Kaplan-Meier survival curve for the high grade group. We confirmed the results statistically and found that there was a significant relationship, with P < .05. CONCLUSION: We strongly advise the use of DNA quantification by image cytometry in daily surgery as a prognostic indicator of survival time in colorectal cancer.

Adenocarcinoma↗
PubMed1999

[Blepharophimosis-ptosis-epicanthus inversus associated with infertility].

Blepharophimosis-ptosis-epicanthus syndrome (BPES) is a rare genetic condition occurring sporadically and transmitted by autosomal dominant inheritance. Type I BPES is associated with a high incidence of menstrual irregularities and infertility. Its clinical presentation is attributed to either an ovarian resistance to gonadotropins or to a true premature menopause. Two pathophysiological underlying mechanisms have been proposed: one suggests that one or more mechanisms lead to inhibition of early follicular development or follicule atresia. The other raises the possibility that BPES results from microdeletion of genetic material containing at least 2 independent genes. We report a familial case of BPES identified at birth and who required several surgical procedures. Several members of the patient's family are also affected. Early recognition of this condition may allow appropriate counselling and/or treatments including egg donation in case of hypergonadotropic hypogonadism.

Adult↗
PubMed1998

Distribution of neurons expressing immunoreactivity for the 5HT3 receptor subtype in the rat brain and spinal cord.

The cellular distribution of the type 3 serotonin receptor (5HT3R) in the rat brain was established immunocytochemically by using a polyclonal antibody raised against a synthetic peptide from the deduced amino-acid sequence of the cloned 5HT3R. The 5HT3R-immunoreactive neurons were found in the forebrain, brainstem, and spinal cord, but within each region, the intensity of the immunoreactivity differed considerably. Within the forebrain, intensely immunoreactive cells were found in layers II-III of the neocortex, anterior olfactory nucleus, hippocampal formation, and amygdala. A few strongly immunoreactive neurons were consistently observed in the caudate putamen, and moderately or weakly labeled neurons were occasionally found in the nucleus accumbens. Within the brainstem, intensely labeled neurons were found in the trigeminal motor (V) and facial (VII) nuclei. Immunostained neurons were detected in the dorsal and the ventral horn of the spinal cord. These results reveal that the 5HT3R-immunoreactive neurons are broadly distributed throughout the rat brain and spinal cord, and suggest that this receptor can subserve significant participation in central nervous system neurotransmission.

Animals↗