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Biomedical subjects

M Rubio

Publications and source records attributed to M Rubio.

At least 163 records · Page 9Linked to original sources
PubMed1993

[Pharmacokinetics of ceftazidime in newborn infants].

A pharmacokinetic study of ceftazidime was performed in newborn children. Six premature infants with a body weight up to 2000 g and with symptoms of pneumonia (Table 1) were treated with ceftazidime (50 mg/kg body weight) by endovenous route. Plasma concentrations of the antibiotic (Fig. 1) were determined by HPLC. A kinetic behavior was described through a compartment model independent analysis. The calculated parameters were as follows: half-life (T1/2z = 4.05 +/- 0.81 h) apparent volume of distribution (Vz = 686.0 +/- 258.6 ml/kg), elimination rate constant (lambda z = 0.18 +/- 0.04h-1), area under curve (AUC = 464.4 +/- 139.1 mu gh/ml, mean residence time (MRT = 5.2 +/- 1.3 h), and total clearance (CI = 114.9 +/- 30.0 ml/h. kg) (Table 2). Good correlation was observed (r = 0.83, p < 0.05 between lambda z = and Vz). The loading and maintenance doses calculated for enterobacteria and P. aeruginosa were 15 and 13 mg/kg i.v. respectively each 12 h.

Ceftazidime↗
PubMed1993

[Epidemiologic and clinical characteristics and clinical course of the HIV positive patient infected by heterosexual transmission].

We reviewed the features of patients with human immunodeficiency virus (HIV) infection, whose only way of acquisition was heterosexual contacts, analyzing differences with others risk groups. Epidemiological features (age, gender, family situation, socioeconomic status and sexual behavior), clinical manifestations immunological status, and evolution of 40 patients with HIV infection through heterosexual contact are studied, and compared with others risk groups. All were attended in our center from 1985 to October 1991; 15 were in stage IV. Along the study period, the proportion of heterosexual patients has steadily increased to represent 40% on total number of acquired immunodeficiency syndrome (AIDS) cases diagnosed in 1991. This study allow to establish two groups of patients depending on the gender. All men had had occasional sexual contacts with prostitutes, most had no stable partner, they mainly were between their fourth and sixth decade of life, and they were stable partners of seropositive patients or prostitutes, they had an averaged age significantly lower than men, and they were diagnosed in earlier stages. Two groups with different features can be established among the patients infected through heterosexual contacts. Men are adults, and acquired HIV infection through contacts with prostitute; they are diagnosed in late phases of the disease. On the contrary, women are younger, with no homogeneous patterns of behavior and they are diagnosed in earlier stages. Complications throughout the evaluation were similar in the heterosexual and in the other groups.

Adult↗
PubMed1993

Creation of a Spanish nephrological nursing accrediting course.

In 1989, the Spanish Association of Nephrological Nursing (Sociedad Espanola de Enfermeria Nefrologica--SEDEN) created a course directed to all graduates in nephrological nursing in Spain to answer a need for further training. This article details the objectives, methodology, and results of the Course for Accrediting Specialized Knowledge in Nephrological Nursing since it was created.

Education, Nursing, Continuing↗
PubMed1993

Ultrastructural and morphometric changes in somatotropic cells following intraventricular administration of Met-enkephalin to rats.

An ultrastructural and morphometric study of Kurosumi et al. (1986) on type 1 GH cells in adult Sprague-Dawley rats, after the intraventricular administration of Met-enkephalin, with or without prior intraperitoneal administration of naloxone, was carried out and then compared to the same cellular type of untreated animals and of animals intraventricularly treated with distilled water, used as controls. The study demonstrated an increase of cellular (p < 0.05) and nuclear (p < 0.05) areas, an enlargement and dilation of the cisternae of the Golgi complex, with an increase in the Golgi area (p < 0.01) and the immature granules (p < 0.01); a greater development of the rough endoplasmic reticulum and an increase in the number of exocytosis (p < 0.01) and, only in male rats, an increase in the mature secretory granules (p < 0.01). The prior administration of naloxone prevented the appearance of these changes and also produced an increase (p < 0.01) of the organelles involved in the crinophagic phenomenon. These results suggest that the opioids play a modulating role, stimulating the synthesis and secretion of GH, which affects the ultrastructural features of the hypophyseal GH cells.

Animals↗
PubMed1992

IL-4 induces conformational change of CD20 antigen via a protein kinase C-independent pathway. Antagonistic effect of anti-CD40 monoclonal antibody.

The CD20 molecule is a unique phosphoprotein exclusively expressed on B cells during most stages of B cell ontogeny. We here report that rIL-4 down-regulates the expression of CD20 with anti-Leu-16 mAb (clone L27) on both unstimulated and anti-mu preactivated normal and leukemic B cells. None of the other recombinant lymphokines tested (IL-1, IL-2, IL-3, IL-6, IFN-alpha, and IFN-gamma, granulocyte/macrophage-CSF, transforming growth factor-beta, TNF-alpha, and lymphotoxin) decreased CD20 expression. Incubation of unstimulated or anti-mu preactivated B cells with IL-4 did not affect the steady state CD20 mRNA, suggesting that IL-4 exerted its effect mainly at a nontranscriptional level. Hence, IL-4 selectively down-regulates the CD20 epitope recognized by clone L27 without affecting seven other different epitopes, indicating that IL-4 acts by modifying the conformation of the CD20 molecule rather than by inhibiting its production or inducing its internalization. IL-4 most likely utilizes a protein kinase C-independent signal transduction pathway to modify CD20 molecule inasmuch as staurosporine, an inhibitor of protein kinase C, antagonizes phorbol esters (PMA) but not IL-4-induced CD20 down-regulation. In contrast, anti-CD40 mAb reverses the IL-4 but not the PMA inhibitory effect on CD20 expression. Given that CD20 may be part of a Ca2+ ion channel and plays a role in B cell activation and proliferation, it is proposed that the ability of anti-CD40 mAb to maintain the CD20 molecule in a given epitopic configuration on IL-4-stimulated B cells may be related to the long term proliferation of normal B cells that are strictly dependent on the presence of IL-4 and cross-linked anti-CD40 mAb for their continuous growth.

Antibodies, Monoclonal↗
PubMed1992

Glial fibrillary acidic protein and vimentin immunohistochemistry in the posterior rhombencephalon of the Iberian barb (Barbus comiza).

The gustatory centers (vagal lobes and facial lobe) and the tegment of the posterior rhombencephalon of the Iberian barb (Barbus comiza) have been studied using anti-glial fibrillary acidic protein (anti-GFAP) and anti-vimentin immunohistochemical techniques. GFAP immunoreactivity was found in the tegment and in a part of the vagal lobes while vimentin immunoreactivity was located in the tegment. Two immunopositive cell types were found: ependymocytes and radial astrocytes. Since the distribution of GFAP in the barb rhombencephalon corresponds with zones previously described as cholinergic, the GFAP-immunopositive radial astrocytes might be involved in acetylcholine metabolism.

Animals↗
PubMed1992

A single mRNA encodes the alpha 150 and alpha 80/70 forms of the alpha subunit of VLA4.

VLA4 is a cell surface heterodimer (alpha 4 beta 1, CD49d/CD29) which belongs to the integrin family and is involved in cell-extracellular matrix interactions, as well as in intercellular adhesion. Unlike other integrin alpha subunits, the alpha subunit of VLA4 (alpha 4) can appear as a 150-kDa polypeptide (alpha 150), or cleaved into two non-covalently associated polypeptides (alpha 70-80). The relative proportion of each form is highly variable among different cells and is dependent on the state of cellular activation. The alpha 4 cleavage site has recently been shown to occur between residues Arg558-Ser559. We report the isolation of genomic clones encoding the alpha 4 subunit, the location of the cleavage site-encoding nucleotides to a specific exon and the determination of the exon-intron organization around the cleavage site. Comparison with the gpIIb (CD41) and the alpha x (p150,95 alpha, CD11c) genes revealed a similar genomic structure in this region, with exons of similar length separated by introns of identical phase. The structure of the alpha 4 mRNA in cells expressing the alternative forms of alpha 4 has been analyzed by means of reverse transcription-polymerase chain reaction. Our results indicate that the exon encoding the cleavage site is present in alpha 4 mRNA molecules from cells expressing either the alpha 150 or the alpha 70-80 form on the cell surface. Moreover, the structure of the alpha 4 mRNA around the cleavage site does not change during the switch towards the alpha 70-80 form that takes place upon lymphocyte activation. Therefore, both forms of alpha 4 arise from a common mRNA, the alpha 150 form contains the cleavage sequence and the alpha 70-80 form must be generated by a post-translational proteolytic event.

Base Sequence↗
PubMed1992

Low-molecular weight B cell growth factor (BCGF-12KD) as an autocrine growth factor in B cell chronic lymphocytic leukemia.

The role of cytokines in the growth and spreading of human hematologic malignancies has been underlined in recent years. Here we report evidence that a human 12-kDa B cell growth factor (BCGF-12KD) may function as a growth stimulatory factor in B cell chronic lymphocytic leukemia (B-CLL). First, recombinant BCGF-12KD induced dose-dependent DNA synthesis in neoplastic B cells of four B-CLL patients tested. Second, seven different B-CLL clones secreted a BCGF-12KD-like product that accounted for their proliferation. A neutralizing monoclonal antibody (mAb; Ac8) directed against a BCGF-12KD synthetic peptide inhibited the spontaneous growth of the leukemic B cells. The same mAb blocked DNA synthesis in normal tonsillar B lymphocytes induced by the culture supernatant of spontaneously proliferating B-CLL cells. Finally, BCGF-12KD mRNA was expressed in freshly isolated (two of three patients) as well as in vitro proliferating B-CLL cells (three of three patients). These findings strongly suggest that BCGF-12KD can modulate the growth of B-CLL cells in vivo as well as in vitro. They may offer significant insights into the biology of this frequent B lymphoproliferative disorder.

Adult↗
PubMed1992

Sexual dimorphism in the hamster cerebellum demonstrated by glial fibrillary acidic protein (GFAP) and vimentin immunoreactivity.

Male and female hamsters aged 1, 4, and 10 postnatal weeks were used to study the distribution of vimentin and glial fibrillary acidic protein (GFAP) in the cerebellum. Vimentin immunoreactivity exceeded that of GFAP during the first postnatal week, although GFAP was also observed in all cerebellar layers. Immunoperoxidase analysis revealed that by the fourth postnatal week vimentin was only detected in Bergmann fibers and the very scarce fibrous astrocytes located in the inner white matter. The Purkinje cell bodies were only coated with GFAP-immunopositive processes. At 10 weeks, vimentin immunoreactivity was reduced to thin Bergmann glial processes, whereas GFAP immunoreactivity had greatly increased in the whole cerebellum. The GFAP immunostaining was denser in males than in females; however, in females, the Bergmann fibers were heavily immunostained with anti-vimentin in contrast to the males. The results described in the present paper indicate a sex difference in vimentin and GFAP immunoreactivities in the cerebellar astrocytes at 4 weeks of age, which persisted in the oldest hamsters in this study. The existence of sexual dimorphism might suggest that the expression of both gliofilament proteins could be influenced by circulating sex steroids.

Animals↗
PubMed1992

Different response of astrocytes and Bergmann glial cells to portacaval shunt: an immunohistochemical study in the rat cerebellum.

The present study was performed in order to follow the response of rat cerebellum astroglial cells (Bergmann glial cells and astrocytes) to long-term portacaval shunt (PCS), by means of glial fibrillary acidic protein (GFAP) and vimentin immunoreactivities. Bergmann glia accumulated GFAP in response to PCS, whereas astrocytes decreased GFAP immunoreactivity when compared to control rats. The increase of GFAP occurs in cells located in the cerebellar layer where glutamate is mainly released. Since the vimentin content remained unaltered in response to PCS, when compared to control rats, it can be concluded that only the GFAP filaments are affected by PCS. Nevertheless, GFAP immunoreactivity presents regional differences in the cerebellar astroglial population, and the factors responsible for these variations are still unknown.

Animals↗
PubMed1992

Morphometrical variations of prolactin cells in response to prolonged and systemic administration of Met-enkephalin in female rats.

A stimulatory effect on prolactin secretion had been describe after acute and systemic administration of met-enkephalin, but the effects of this opioid after chronic administration has not been reported, and the response of mammotroph cells is not clear. As a complement to previous studies, a morphometric analysis (light and electron microscopy) was carried out on prolactin cells from female rats treated chronically with met-enkephalin. Clear features of cellular hyperactivity appeared after chronic and systemic administration of the opioid, and these persisted for two weeks. The changes consisted in increases of cellular, cytoplasmic and nuclear areas, volume and surface densities of the Golgi complex and rough endoplasmic reticulum, as well as the numbers of exocytotic figures. These morphological alterations were paralleled by an increase in serum prolactin levels as detected by RIA. It is concluded that the increase in the synthesis and secretory activity of prolactin cells following chronic and systemic administration of met-enkephalin is very similar to those observed after acute and intraventricular administration.

Analysis of Variance↗
PubMed1992

Immunocytochemical evidence of hypothalamic regulation of adenohypophyseal VIP in the male rat.

In order to check whether hypothalamic stimulatory or inhibitory factors exert any kind of modulation on the morphology of VIP-immunoreactive cells in the rat hypophysis, the transport of these towards the hypophyseal portal system was blocked by intraventricular administration of colchicine in adult male rats, thereafter performing a morphometric study after characterizing the VIP-immunoreactive adenohypophyseal cells by immunocytochemical techniques. Colchicine administration led to a significant increase (p < 0.01) in the number of reactive cells observed. These cells were characterized by a larger cellular area (p < 0.01), owing to increases in nuclear area (p < 0.05) and cytoplasmic area (p < 0.05). Their morphology became more regular, with a predominance of polygonal and oval cells. The results suggest that the VIP-reactive cells of the rat hypophysis are subject to a hypothalamic inhibitory influence and their activity increasing when the hypothalamic effect is interrupted by intraventricular administration of colchicine.

Animals↗
PubMed1992

Hyperammonemia induces transient GFAP immunoreactivity changes in goldfish spinal cord (Carassius auratus L.).

In this study we have demonstrated that high ammonia concentration in tank water induces changes in the glial fibrillary acidic protein (GFAP) of ependymal cells and radial astrocytes in the goldfish spinal cord. Hyperammonemia was induced by elevating the ammonia concentration in the tank water to 0.88 mM using ammonium chloride; ammonia in control water was less than 0.1 mM. Immunohistochemical methods were used for GFAP and vimentin, and levels were measured at 4, 8, 16, 30, 60, 90 and 120 days. GFAP quantification was made by means of a digital analysis system. The GFAP immunoreactivity was significantly lower at 30 and 60 days of treatment and at 90 days it had returned to control levels. However, no changes in vimentin immunoreactivity were appreciated in any case. GFAP loss was general and was not selective in any specific spinal cord region. To explain this transient generalized loss of GFAP and its posterior recuperation, a possible relation between glutamine synthetase distribution and GFAP changes is discussed.

Ammonia↗
PubMed1992

Estradiol influences the LH response to met-enkephalin. An immunocytochemical and morphometric study.

In order to test the possible role of estradiol in the response of the LH-adenohypophyseal cells to the administration of met-enkephalin in the albino male rat, an immunocytochemical (peroxidase-antiperoxidase), morphometric (cellular and nuclear areas and numerical density) and radioimmunoassay (LH serum levels at the moment of sacrifice) study was carried out. The intraventricular administration of met-enkephalin (150 micrograms in 25 microliters of distilled water) does not produce any changes in the parameters considered. However, when the animals were pretreated with estradiol (chronically, 15 days), met-enkephalin produced a significant decrease in all the parameters considered.

Animals↗
PubMed1992

CD23 antigen regulation and signaling in chronic lymphocytic leukemia.

B lymphocytes from patients with chronic lymphocytic leukemia (B-CLLs), strongly express the CD23 antigen, a surface marker with significant prognostic importance in this disease. Because we previously reported that IL-4 shows a poor capacity for CD23 expression on B-CLLs, we first examined the possible mechanisms underlying CD23 overexpression on B-CLLs and found that mitogen-activated CLL T cells release soluble factors that are capable, in synergy with IL-4, of strongly inducing CD23. Using neutralizing Abs, we noticed that the T-cell-derived enhancing activity is entirely ascribed to the combined effects of IFN gamma (potent inhibitor of CD23 on normal B cells), TNF alpha (which has no effect on normal B cells), and IL-2 (which has a slight enhancing effect on both CLL and normal B cells). Furthermore, recombinant IFN gamma as well as IFN alpha, TNF alpha, and IL-2 (but not IL-3, IL-5, IL-6, IL-7, and lymphotoxin) significantly enhance CD23 protein and mRNA expression on B-CLLs, in the presence or absence of IL-4. Inasmuch as optimal CD23 expression absolutely requires the combination of IFN gamma, IL-2, TNF alpha (the production of which is increased in CLL disease), and IL-4, it was relevant to show that IL-4 mRNA is indeed expressed in fresh T-CLL cells. We next examined the possible role of CD23 in the regulation of B-CLL proliferation. Signaling through CD23 via ligation of the antigen by F(ab')2 anti-CD23 MAb but not Fab fragments inhibits the cytokine-induced B-CLL DNA synthesis. It is concluded that the CD23 gene is abnormally regulated in B-CLL disease and that cross-linking of CD23 molecule delivers a negative growth signal to the leukemic B cells.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1992

Morphometric changes in GH-immunoreactive adenohypophyseal cells induced by intraventricular administration of colchicine to adult rats.

In order to elucidate whether the gender differences observed in the somatotropic cells of adult rats are mediated by hypothalamic neuropeptides, a morphometric analysis was made of the GH-immunoreactive cells of adult rats treated intraventricularly with colchicine. The morphometric and morphological findings obtained were correlated to the basal serum levels of GH at the time of sacrifice. Treatment with colchicine was seen to increase serum GH levels; this increase was accompanied by an increase in the intensity of the reaction of the GH-cells and, morphometrically, an increase in their size due to an increase in the nuclear area, but with no significant changes in the cytoplasmic area. The results suggest that in the absence of somatostatin and GRF the basal release of GH is elevated in a similar fashion in both sexes, in turn suggesting that gonadal steroids might act at hypothalamic level on the release of somatostatin and, indirectly, on the intracellular pool of GH and hormonal secretion.

Animals↗
PubMed1992

Expert computer program for the management of laser surgery.

Since 1960 when the first laser was produced, different types of lasers were developed and over one hundred of them are actually used in medicine. These facts makes very difficult for a surgeon to optimally utilize different types of laser in varying surgical circumstances, unless a laser expert is actually participating in the procedure. As this presence is impractical, if not impossible in every case, we are offering a computer program which presents information in a flexible and friendly way; it is self perfecting and greatly expandable.

Humans↗