PubMed Health⌕ Search

Biomedical subjects

A García

Publications and source records attributed to A García.

At least 199 records · Page 11Linked to original sources
PubMed1998

Foreign body impaction in the esophagus: are there underlying motor disorders?

UNLABELLED: We observed in our practice several cases of impaction with meat boluses without bony edges, in patients with patent esophageal lumen. The aim of this study was to search for eventual underlying motor disorders which could be responsible for this impaction. We included 19 patients who attended the endoscopy service for meat bolus impaction without organic esophageal stenosis. This group was compared with 18 control volunteers. Both groups underwent UGI series, UGI endoscopy and low-compliance perfusion standard esophageal manometry. RESULTS: Compared with the control group, the impacted subjects presented marked reduction in amplitude and duration of esophageal contraction in the proximal esophagus. CONCLUSIONS: These motor disorders could be responsible for the foreign body impaction in the esophagus. However, we believe this patient group should be further studied by 24-hour esophageal manometry to reach a more accurate diagnosis by studying each patient's entire circadian cycle.

Adolescent↗
PubMed1998

Ovarian germ cell tumors.

UNLABELLED: Ovarian germ cell tumors (OGCT) are a special type of ovarian cancers due to their histology, age of presentation, prognosis and treatment. MATERIAL AND METHODS: Eighteen cases of OGCT out of 313 total ovarian cancer diagnosed in Hospital Materno-Infantil Vall d'Hebredn between 1975 and 1994 are present. RESULTS: Mean age of the patients was 36 years. The most frequent symptom at diagnosis was abdominal bloating (44.5%). Echography was the most used diagnostic method (67%). Surgery was conservative in 44% of the cases, radical in 50% of the cases and palliative in one case. The histological types were 6 dysgerminomas and 6 malignant teratomas (33.3%), 3 malignant dermoid cysts (16.7%), 2 yolk sac tumors (11%) and 1 embryonal carcinoma. According to FIGO 1987 staging classification 14 patients were in stage I disease and 4 in stage III disease. Polychemotherapy was performed on 6 patients and postsurgical radiotherapy was performed on 2 patients. Five patients recurred in an average time of 25 months. The five-year survival rate, according to the Kaplan-Meier method, was 80% in stage I and 0% in stage III. Five-year survival rate of patients only surgically treated was 65% and in patients who underwent postsurgical co-adjuvant treatment it was 100%. CONCLUSION: Conservative surgery followed by a BEP regimen may be performed nowadays with efficacy and acceptable toxicity while conserving the fertility of these patients.

Adolescent↗
PubMed1998

[Miller-Fisher syndrome: electrophysiological serial study of five patients].

OBJECTIVE: The object of the present study is to show the spectrum of neurophysiological findings during clinical course of Miller Fisher syndrome (MFS), avoiding the controversy over a combined central and peripheral pathology. PATIENTS AND METHODS: We report five patients with a syndrome of ophthalmoplegia, ataxia and areflexia. A similar episode had been suffered previously by 2 of these patients, 14 and 13 years before. In one of them the second episode evolved to a typical Guillain-Barré syndrome (GBS). Motor and sensory conduction velocity of upper and lower limbs, F waves, blink-reflex and somatosensory evoked potentials were recorded in all cases. Needle electromyography in four and brainstem evoked potentials in three of them and the jaw-reflex in another one. RESULTS: In all patients there was a markedly reduced amplitude of the distal sensory evoked response, and no signs of denervation in the EMG. The other results were variable both interindividually and intraindividually. The severity of abnormalities was also different between different patients. The clinical recovery was always accompanied by a improvement of neurophysiological parameters. CONCLUSIONS: The electrophysiological findings in MFS can be variable but they appear always related with the clinical symptomatology. We report for the first time a case in whom the jaw-reflex was abnormal whereas the blink-reflex was normal.

Adult↗
PubMed1998

Capillary electrophoresis for rapid profiling of organic acidurias.

Organic acids analysis is a powerful technique in the diagnosis of inborn errors of metabolism. Clinically, patients present with severe symptoms, and early detection and appropriate treatment are often lifesaving. Most of the existing methods are based on gas chromatography in combination with mass spectrometry and require sophisticated equipment and complex sample pretreatment and derivatization. We propose a rapid, simple, and automated capillary electrophoretic method for routine analysis of urine to detect 27 organic acids related to metabolic diseases. With this method, direct measurements are performed on samples after initial centrifugation and dilution, if needed. Separation is performed in pH 6.0 phosphate buffer with methanol added as an organic modifier, -10 kV applied potential, and ultraviolet detection at 200 nm. The assay is completed in <15 min, and alternative separation conditions are proposed in case of overlapping peaks. The developed method allows the identification and quantitation of methylmalonic, pyroglutamic, and glutaric acids in samples of patients with diseases related to these acids.

Carboxylic Acids↗
PubMed1998

[Simultaneous transplantation of fetal mesencephalic cells to the striatum and globus pallidus of rats with lesions induced by 6-hydroxydopamine].

INTRODUCTION: Studies of neural transplants in experimental models of Parkinson's disease have concentrated their attention on ectopic transplants of foetal mesencephalic cells to denervated striatum. However, the external globus pallidus has recently been shown to play an important part in the physiopathology of this disease. OBJECTIVE: Bearing in mind the importance of loss of extra-striatal dopamine in the genesis of the clinical signs found in parkinsonism, the objective of this study was to evaluate the effect of foetal mesencephalic transplantation to the globus pallidus of hemiparkinsonian rats. MATERIAL AND METHODS: Following conventional transplantation methodolgy, suspensions of cells from the ventral mesencephalum of rat embryos (E-14) were implanted. The tissue was grafted into the striatum, pallidum-striatum and pallidum areas of rats with unilateral lesions of the striatonigral bundle. One, two, three and six months after transplantation, the rotatory activity induced by D-amphetamine was evaluated. The rotatory behaviour induced by apomorphine was evaluated at three months. Motor ability of the front legs was evaluated in all experimental groups three months after transplantation using the 'ladder test'. RESULTS: In the experimental groups in which a transplant was made to the globus pallidus there was a significant reduction (p < 0.01) in rotatory activity induced by D-amphetamine and by apomorphine as compared with the non-transplanted groups. CONCLUSIONS: Transplants of foetal dopaminergic cells survive in the globus pallidus of hemiparkinsonian rats and can improve the rotational activity induced by dopaminergic agonists.

Adrenergic Agents↗
PubMed1998

[Radionuclide bone scanning in patients with breast carcinoma. Study of lesions by stages, locations and diagnostic assessment].

The aim of this study was to evaluate the diagnostic role of bone scan in patients with breast carcinoma. With this purpose, we have studied 591 patients (4 males). In 261 of them, we were able to establish the stage of disease: 33 in stage I, 137 in stage II, 71 in stage III y 20 in stage IV. Metastatic lesions were detected in 6% of patients in stage I, 8.8% in stage II, 12.7% in stage III y 50% in stage IV. Altogether, 71 from 591 patients (12%) had metastatic lesions. In 4 patients (5.3%) we obtained a false positive result. The bone lesions found in the scintigraphic studies were classified as not metastatic lesions in 236 patients (39.9%) but 26 of them were malignant (11%). Another 193 patients (32.6%) presented scintigraphic studies considered as equivocal for metastasis and 33 of them were also malignant (17%). In 150 patients scintigraphic studies did not present lesions during the follow up. In other 156 patients isolated lesions were detected and 24 of them (15.4%) were malignant. Only 4 < > lesions were detected and not any < > image was observed in this study.

Adult↗
PubMed1998

[Usefulness of determining low-avidity IgG antibodies in the diagnosis of primary rubella infection in pregnant women].

BACKGROUND: It is necessary to have an easy and quickly test to distinguish "false positive" rubella IgM results and residual antibodies from the antibodies produced in the primary infection, in pregnant women. The avidity of IgG antibodies test seems to differentiate between primary rubella infection and past infections, reinfections or postvaccination, showing its utility in the diagnosis of primary infection in other infectious diseases. METHOD: For 30 months, 178 sera from 157 patients with clinical and/or epidemiological rubella suspicion or with a positive rubella IgM result as result of an accidental serological finding, were remitted to our laboratory for a serological follow up. We distinguished 3 patient groups: outbreak group, 112; pregnant women, 36, and newborn 11. Rubella IgM antibodies by indirect EIA previous the rheumatoid factor absorption; IgG antibodies of low avidity by indirect EIA previous treatment of serum with 6 M urea, were detected in the sera. It considered a positive result, a rubella avidity index (AI) < 50%. RESULTS: In the epidemic outbreak group, 90.2% of the patients were not vaccinated. 80% of cases occurred in young men between 14 an 20 years old. From 109 patients (97.3%) with rubella IgG antibodies, 92 (84.4%) showed AI-IgG lower than 50%. In this group, the mean rate of AI-IgG rubella was 29.0%. In the pregnant women group, except for two of them, rubella IgM antibodies were an accidental finding in a serological pregnancy screening. Thirty patients (83.8%) showed AI-IgG rubella > 50%. The two pregnant women who had evidence of clinical and epidemiological rubella showed AI-IgG rubella of 37.4% and 20.9%. Another four pregnant women showed AI-IgG rubella close to cut-off (44.7-49.0%). The mean AI-IgG rubella in this group was 71.8%. The mean AI-IgG Rubella between the epidemic outbreak group and the pregnant women group, 29.0 and 71.8% respectively, was statistical significance (p < 0.001). CONCLUSIONS: The avidity IgG test is simple and quickly, and it allow to exclude most of positive results because of residual IgM antibodies and false reactive.

Adolescent↗
PubMed1998

Microsatellite instability in cervical intraepithelial neoplasia.

We studied the incidence of microsatellite instability (MI) in lesions defined as cervical intraepithelial neoplasia (CIN). The human papillomavirus (HPV) status of the tissues was also determined. DNA from tissue samples and autologous lymphocytes were studied for five loci located within or adjacent to the DNA mismatch repair genes. Replicate errors were detected in 7 out of 47 (14.8%) samples of cervical tissue from 24 women. Our results indicate that the defect in DNA repair-associated genes does not appear to be necessary for the selection of clones which progress from dysplasia to carcinoma. Although HPV DNA of highly oncogenic types (16/18) was detected in most cervical lesions and may be an important factor for MI, we also detected MI in two loci in HPV-negative normal tissue, indicating that further events can also be involved in mismatch repair defects.

Adult↗
PubMed1997

Differences in the stimulation of the phosphoinositide cycle by amine neurotransmitters in cultured rat forebrain neurones and astrocytes.

In this study, we compared the stimulation by carbachol (CCh), noradrenaline (NA), and histamine (HA) of phosphoinositide hydrolysis in rat forebrain neuronal and glial cultures. When Ca2+ was omitted from the stimulation buffer (low microM extracellular Ca2+), amine-induced [3H]inositol phosphate accumulation was reduced to a higher extent in astrocytes (70-80% for CCh and NA and 100% for HA) than in neurones (around 50-60% for all the amines). Furthermore, guanosine 5'-[gamma-thio]trisphosphate (GTP[S]) stimulation of phosphoinositidase C (PIC) in membranes was 5-fold higher in neurones than in astrocytes. These results indicate differences in the mechanism of PIC stimulation in the two cell types. After 30 min stimulation in the presence of 10 mM Li+, a higher accumulation of [3H]inositol 4-monophosphate and [3H]inositol 1,4-bisphosphate than of [3H]inositol 1/3-monophosphate occurred for all agonists in neurones, whereas the opposite was observed in astrocytes. Moreover, in these cells stimulation for 5 min in the absence of Li+ produced a 2-3-fold accumulation of all metabolites of the 3-kinase pathway of inositol-1,4,5-trisphosphate metabolism but not of those of the 5-phosphatase pathway. Thus, regardless of the amine receptor stimulated, the 3-kinase route appeared to prevail in astrocytes and the 5-phosphatase pathway in neurones. The histamine response in neurones differed from that of the other agonists in that it rapidly declined. Taken together these results indicate that the heterogeneity in amine stimulation of the phosphoinositide cycle previously observed in brain slices could arise to a great extent from the cellular diversity of this preparation and be related to the differential contribution of the amine receptors located in neurones and astrocytes.

Animals↗
PubMed1997

Regulation by calcium of the nitric oxide/cyclic GMP system in cerebellar granule cells and astroglia in culture.

Ca2+ entry induced by N-methyl-D-aspartate (NMDA) in neurons and by noradrenaline (NA) in astrocytes is known to increase intracellular cyclic GMP (cGMP) levels through stimulation of the Ca2+-dependent nitric oxide synthase type I (NOS-I). The possibility that Ca2+ entry could also down-regulate intracellular cGMP by activating a Ca2+/calmodulin-dependent phosphodiesterase (CaM-PDE) has been investigated here in primary cultures enriched in granule neurons or in astroglia from rat cerebellum. We show that the same agonists that stimulate nitric oxide (NO) formation (NMDA and NA at 100 microM) and the Ca2+ ionophore A23187 (10 microM) decrease cGMP generated in response to direct stimulation of soluble guanylyl cyclase (sGC) by NO donors in both cell types. This effect requires extracellular Ca2+ and is prevented by the calmodulin inhibitor W7 (100 microM). Membrane depolarization, manipulations of the Na+ gradient, and intracellular Ca2+ mobilization also decrease NO donor-induced cGMP formation in granule cells. In astroglia Ca2+ entry additionally down-regulates cGMP generated by stimulation of the particulate GC by atrial natriuretic peptide (ANF). Decreases in cGMP produced by A23187 were more pronounced in the absence than in the presence of the PDE inhibitor 3-isobutyl-1-methylxanthine (IBMX; 1 mM), indicating that a CaM-PDE was involved. We also show that astroglial cells can accumulate similar amounts of cGMP than neurons in response to NO donors when IBMX is present but much lower levels in its absence. This may result from a lower ratio of sGC to PDE activities in astroglia.

1-Methyl-3-isobutylxanthine↗
PubMed1997

Mycoflora of paddy and milled rice produced in the region of northeastern Argentina and southern Paraguay.

Thirty samples of paddy rice and twenty-five of milled rice were obtained from processing centers located in two northern Provinces of Argentina and one southern Province of Paraguay. Contaminating fungi were enumerated by direct plating on dichloran rose bengal chloramphenicol agar and oxytetracycline glucose yeast extract agar before and after surface disinfection. All fungi were isolated and identified to the genus level and percentage infection of samples calculated. Those belonging to the genera Penicillium, Aspergillus and Fusarium were identified to species level. The surface mycoflora was dominated by storage fungi, notably Penicillium citrinum (73% of samples), P. islandicum (60% of samples), Aspergillus niger, A. flavus and Fusarium semitectum. The major fungi found as internal contaminants of paddy rice were, again, Penicillium citrinum (66% of samples) and P. islandicum (50% of samples). Milled rice showed a lower level of contamination, but with a similar species distribution, Penicillium citrinum and P. islandicum again being the main contaminants. The presence of these species suggests a potential for mycotoxin production. Further studies are needed to establish the mycotoxin quality of rice from this region.

Fungi↗
PubMed1997

Ca2+/calmodulin-dependent cyclic GMP phosphodiesterase activity in granule neurons and astrocytes from rat cerebellum.

Cyclic GMP (cGMP) formation induced by agonist stimulation of Ca2+/calmodulin-dependent nitric oxide (NO) synthase type I is known to occur in both granule cell and astrocyte cultures from rat cerebellum. Here we show that in these same cells cGMP is predominantly hydrolyzed by a Ca2+/calmodulin-dependent phosphodiesterase. At 10 microM cGMP, Ca2+ (25 microM) stimulated basal (Ca(2+)-independent) phosphodiesterase activity about 6 times in granular neurons and 15 times in astrocytes. The calmodulin antagonist calmidazolium blocked the Ca(2+)-dependent phosphodiesterase activity and exogenous calmodulin increased 3-4-fold the stimulatory potency of Ca2+ in both cell types (EC50 values 1.26 +/- 0.20 and 1.50 +/- 0.42 microM in the absence and 0.38 +/- 0.11 and 0.39 +/- 0.14 microM in the presence of 1 microM calmodulin, for neurons and astrocytes, respectively). In both cell types K(m) values for cGMP at 25 microM Ca2+ were similar (1.72 +/- 0.20 and 1.92 +/- 0.09 microM) and phosphodiesterase activities were inhibited by isozyme-selective phosphodiesterase inhibitors with potencies analogous to those described for Ca2+/calmodulin-phosphodiesterases or phosphodiesterase type 1 isoforms in other preparations. The nonselective phosphodiesterase inhibitor 3-isobutyl-1-methylxantine (IBMX) effectively blocked the Ca2+/calmodulin-phosphodiesterase activity in granule cell and astrocyte extracts (IC50 values at 1 microM cGMP: 31 +/- 10 microM and 46 +/- 6 microM, respectively), in contrast to the apparent inability of this compound to inhibit the Ca(2+)-dependent activity reported in whole brain extracts. These results demonstrate that comparable phosphodiesterase type 1 activities are found in the cytosols of cerebellar granule cells and astrocytes and suggest that these activities may play an important role in controlling cGMP levels in cells where the Ca(2+)-dependent NO synthase type I is stimulated.

1-Methyl-3-isobutylxanthine↗
PubMed1997

IL-2 signaling controls actin organization through Rho-like protein family, phosphatidylinositol 3-kinase, and protein kinase C-zeta.

IL-2 and IL-4 induce proliferation of TS1 alpha beta cells. Activation of the zeta isoform of protein kinase C is an important step in IL-2-, but not IL-4-mediated proliferation. In addition, protein kinase C-zeta is implicated in IL-2-mediated actin organization. Given the established involvement of the Rho family of small guanine nucleotide-binding proteins in organization of actin structures, we analyze the possible relationships between Rho and protein kinase C-zeta. Using the Rho-like protein family-specific toxin B from Clostridium difficile, we report in this work that IL-2, but not IL-4, induces a Rho-dependent activation of protein kinase C-zeta. This signaling event is mediated by the activation of phosphatidylinositol 3-kinase. In contrast, IL-4 induces a Rho-independent, phosphatidylinositol 3-kinase-mediated activation of protein kinase C-zeta, but this pathway has no implications in cytoskeleton organization.

Actins↗
PubMed1997

Tetrasomy 5p mosaicism due to an extra i(5p) in a severely affected girl.

We present a case of mosaic 5p tetrasomy. The mosaicism 46,XX/47,XX,+i(5p) was found at different ratios in blood lymphocytes, skin fibroblasts, and chondrocytes. The origin of the extra isochromosome was confirmed by FISH. The clinical picture corresponds to that described in trisomy 5p patients, although it was more severe than the two previously reported cases of mosaic 5p tetrasomy. No correlation between clinical severity and proportion of tetrasomic cells in blood or fibroblasts was found in these cases.

Abnormalities, Multiple↗
PubMed1997

Time-dependent changes of serum gastrin and gastrin receptors in the rat oxyntic mucosa after proximal gastric vagotomy.

Proximal gastric vagotomy (PGV) is a first-choice approach for the surgical treatment of duodenal peptic ulcer. However, a high percentage of recidivism takes place after this surgical strategy. To study the possible involvement of gastrin in ulcer recidivism, serum gastrin levels and gastrin receptors in gastric mucosa were determined at several times after PGV in rats. Gastrin concentration was determined using a commercial radioimmunoassay kit and gastrin receptors were analyzed in oxyntic mucosa membrane preparations using 125I-labeled 15-Leu-gastrin-17 as label. Our results show a significant, time-dependent increase in serum gastrin concentration, reaching highest values at 12 weeks after PGV. Similarly, a significant increase in the number of gastrin receptors (Bmax) and in the dissociation constant (Kd) occurred from 1 to 12 weeks post-PGV. Since gastrin exerts a positive feedback effect on its receptors, the PGV-dependent increase in serum gastrin concentration explains the up-regulation of the gastrin receptors in the rat oxyntic mucosa. Furthermore, an increase in the number of gastrin receptors after vagotomy may be at least partially responsible for the recidivism in duodenal peptic ulcers after this surgical approach.

Animals↗
PubMed1997

Fulminant Guillain-Barré syndrome with universal inexcitability of peripheral nerves: a clinicopathological study.

The pathological basis of nerve inexcitability in Guillain-Barré syndrome has not been established with certainty. We report the clinicopathological findings in a 67-year-old patient with fulminant Guillain-Barré syndrome who died 18 days after onset. Three serial electrophysiological studies revealed nerve inexcitability. Antibodies to Campylobacter jejuni were present but there was no antiganglioside reactivity. Spinal root sections revealed extensive and almost pure macrophage-associated demyelination with occasional presence of T lymphocytes and neutrophil leukocytes. Conversely, in femoral, median, and sural nerves the outstanding lesion was axonal degeneration, with some denuded axons remaining. Unmyelinated fibers, posterior root ganglia, and dorsal columns were preserved. Endoneurial postcapillary venules showed plump endothelial cells with loss of their tight junctions. We conclude that both primary demyelination and axonal degeneration secondary to inflammation account for nerve inexcitability. Our findings lend support to the hypothesis of increased endoneurial pressure as the cause of wallerian degeneration in nerve trunks.

Action Potentials↗
PubMed1997

Ras activation leads to cell proliferation or apoptotic cell death upon interleukin-2 stimulation or lymphokine deprivation, respectively.

Lymphokine-dependent cells undergo apoptosis upon lymphokine withdrawal. We describe that lymphokine deprivation of the interleukin (IL)-2- or IL-4-dependent mouse T cell line TS1 alpha beta induces Ras activation which plays a role in programmed cell death, since blocking Ras activity reduces the induction of apoptosis. Induction of apoptosis by lymphokine deprivation can be prevented by expression of the Bcl-2 protein. Rescue from cell death by IL-2 also promotes Ras activation, but, in contrast to lymphokine withdrawal, stimulates Bcl-2 expression. IL-4-induced cell survival is Ras- and Bcl-2 independent. These results are compatible with a model in which cell proliferation requires the simultaneous induction of at least two pathways which act in combination to prevent cell death.

Animals↗