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Biomedical subjects

M Ramírez

Publications and source records attributed to M Ramírez.

At least 145 records · Page 8Linked to original sources
PubMed1983

Prevalence of bancroftian filariasis in the city of Puerto Limón and the province of Limón, Costa Rica.

Examination of blood from randomly selected residents in four subdivisions of Puerto Limón, Costa Rica, demonstrated Wuchereria bancrofti infection in 1.8% of 2,879 persons. Previous studies in four other subdivisions of the city revealed infection in 2.7% of 2,338 persons. In both studies the microfilaremia rate in males was approximately twice that in females. Distribution by race was similar in the two surveys, with microfilaremia in 1% of 1,052 white and 4.1% of 1,286 black residents in the first survey and 0.8% of 2,216 white and 5.4% of 663 black residents in the second. The highest rate of infection was in the 10-to 19-year-old and over 40-year-old age groups. In 13 rural communities near Puerto Limón, infection was found in only three (0.1%) of 3,448 individuals (27% of the population). Dissection revealed filarial larvae in 164 (6%) of 2,714 female Culex pipiens fatigans captured in 137 of 140 urban houses and in none of 936 from rural houses. Precipitin tests on stomach contents of 643 C. p. fatigans showed that 85% had taken human blood. The results indicate that endemic bancroftian filariasis in the Puerto Limón area is restricted to the urban population.

Adolescent↗
PubMed1983

Monoamines and self-stimulation of the medial prefrontal cortex in the rat.

The participation of noradrenaline (NE) and serotonine (5-HT) in self-stimulation (SS) of the medial prefrontal cortex (MPC) in the rat has been studied. Three groups of rats with bilateral electrodes implanted into the MPC were used in these experiments. In one of the groups, electrodes were also implanted into the locus coeruleus. In the first group, the rats received systemic injections of the following drugs: clonidine (alpha-agonist), phenoxybenzamine (alpha-antagonist), isoproterenol (beta-agonist) and propranolol (beta-antagonist). In the second group, p-chlorophenylalanine (a 5-HT synthesis inhibitor) was administered intragastrically and SS measured during the following 16 days. In these two groups of rats and previous to every SS session, spontaneous motor activity (SM) was measured as control for non specific effects of the drugs. In a third group of rats, lesions of the locus coeruleus were performed unilaterally and SS measured in both prefrontal cortex during the following 16 days post-lesion. SS contralateral to the lesioned side served as control for non-specific effects of the lesions. After all these treatments, SS of the MPC was not specifically affected. Our results suggest the non participation of NE and 5-HT terminals in the neural substrates underlying SS of the MPC.

Adrenergic alpha-Antagonists↗
PubMed1982

Co-occurrence of albumin complexes with IgE and IgG in the serum of an IgE myeloma patient.

The serum of a patient with a clinically and immunologically identified multiple myeloma of the IgE class was found to contain both IgE-albumin and IgG-albumin complexes. These complexes were partially purified and some of their properties studied by biochemical and immunochemical methods. The IgG-albumin interaction was dissociated by 5.0 M guanidine hydrochloride, while the IgE-albumin interaction was dissociated upon reduction by mercaptoethanol, suggesting that the proteins were linked by intermolecular disulfide bonds. Complex formation between pathological or normal immunoglobulins with albumin have been reported for IgG, IgM and IgA but not for IgD or IgE. The present observation seems to be the first in which an IgE myeloma protein was involved.

Chemical Phenomena↗
PubMed1980

Bence Jones myeloma with a tetramer of kappa-type globulin in serum.

We describe a case of Bence Jones multiple myeloma involving two kappa-type monoclonal proteins. One was isolated from serum, the other from both serum and urine. After biochemical and immunochemical analyses, we concluded that one of the proteins was a tetramer, present in serum but not in urine, whereas the other was a monomer, which was excreted in large amounts in the urine during the terminal stage of the disease.

Bence Jones Protein↗
PubMed1977

[Porphyrins].

Explore the source record for details and available documents.

Genetic Counseling↗
PubMedDate not supplied

Complicated pulmonary aspergillosis with pneumothorax and pneumopericardium in a child with acute lymphoblastic leukemia.

Invasive aspergillosis is a fungal infection that is being observed increasingly in immunocompromised patients due to the use of more aggressive chemotherapeutic regimens. To our knowledge, no case of pneumothorax and pneumopericardium associated with invasive pulmonary aspergillosis has been reported to date. High-dose amphotericin B (1 to 1.5 mg/kg/day) is the treatment of choice, although severe side effects, especially hypokalemia, are very common. Itraconazole is considered to be a therapeutic alternative for invasive pulmonary aspergillosis in immunocompromised patients. A rare combination of pneumothorax and pneumopericardium associated with systemic aspergillosis in a child with acute lymphoblastic leukemia is described. Treatment with low-dose amphotericin B and itraconazole achieved complete resolution of the foregoing complications.

Amphotericin B↗
PubMedDate not supplied

[The influence of oleic acid on the aminopeptidase activity in astrocytes of the rat].

INTRODUCTION: Changes in fatty acid composition of membrane lipids induce modifications on the activity of several enzymes and membrane transporters. Glial cells possess aminopeptidases which are located in the plasma membranes. Aminopeptidases are generally zinc-metalloenzymes which hydrolyze peptide bonds near the N-terminal end of peptides and polypeptides. The importance of these enzymes is based on their major role in protein metabolism and in the regulation of circulating hormones and biologically active peptides. OBJECTIVE: We study the effects of oleic acid on several aminopeptidase activities in primary cultures of rat astroglia, using aminoacyl-beta-naphthylamides as substrates. RESULTS: Oleic acid inhibits Ala-, Cys-, Leu- and Tyr-aminopeptidase activities, but not modifies Arg- and pGlu-aminopeptidase activities. CONCLUSIONS: Oleic acid modulates aminopeptidase activities in astrocytes. This could be related with intercellular communication and molecular transport processes, in which the astrocyte function has been involved. Furthermore, oleic acid might modulate the action of opioid peptides and steroid hormones on astroglial cells.

Aminopeptidases↗
PubMedDate not supplied

[In vitro study of the effect of ethanol on pyroglutamyl aminopeptidase activity in mouse synaptosomes under basal and stimulated conditions].

INTRODUCTION AND OBJECTIVE: Pyroglutamyl aminopeptidase (pGluAP) is an omega peptidase which removes pyroglutamyl N-terminals residues from peptides and arylamidase derivatives. This activity is thought to be involved in the regulation of several physiological mechanisms on the central nervous system. pGluAP can modulate various susceptible endogenous substrates such as thyrotrophin-releasing hormone (TRH). It is well known that TRH plays an important role in the modulation of the behavioral changes induced by ethanol and others drugs. The aim of this work was to study the in vitro effects of ethanol (25, 50 and 100 mM) on the pGluAP activity and its ability for modulating the TRH. MATERIAL AND METHODS: pGluAP activity was measured in synaptosomes from cerebral cortex of mouse, using pyroglutamyl-beta-naphthylamide as substrate in basal and stimulated (K+ 25 mM) conditions, and in presence or absence of calcium on the buffer. RESULTS: In basal conditions, ethanol produced an inhibition of the pGluAP activity in presence or absence of calcium, being this inhibition non dose-related. However, the stimulation with K+ 25 mM did not produce a modification of pGluAP activity in presence of calcium, but produced a light increase in absence of it. Depolarization in presence or absence of calcium and ethanol produced an inhibition of pGluAP activity, which changed in function of the ethanol concentration used. CONCLUSIONS: Ethanol modifies pGluAP activity in basal conditions by a mechanism independent of calcium, but the changes observed after the stimulation with high K+ may be due to a calcium-dependent mechanism. These variations of pGluAP activity induced by ethanol, and their effects on their endogenous substrates, specially TRH, may be responsible for the behavioral changes associated to the alcoholism and mediated by TRH.

Animals↗
PubMedDate not supplied

Identification of Aeromonas strains of clinical origin with atypical phenotypical profiles.

A total of 47 strains of Aereomonas isolated from patients with gastroenteritis was analyzed for 40 phenotypical characters and for evaluating the numeric taxonomy based on 27 discriminatory tests. It was proved that the clinical isolates showed a relative phenotypical distance and the groups of strains that had atypical profiles were compared with the type species by the present identification schemes.

Aeromonas↗