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Biomedical subjects

E González

Publications and source records attributed to E González.

At least 19 recordsLinked to original sources
PubMed1995

The proximal straight tubule (PST) basolateral cell membrane water channel: selectivity characteristics.

Proximal straight tubules (PST) were dissected from rabbit kidneys, held by crimping pipettes in a chamber and bathed in a buffered isosmotic (295 mOsm/kg) solution containing 200 mM mannitol (MBS). Changes in tubule diameter were monitored on line with an inverted microscope, TV camera and image processor. The PST were then challenged for 20 sec with MBS made 35 mOsm/kg hyperosmotic by addition of either NaCl, KCl, mannitol (M), glycerol (G), ethylene glycol (E), glycine (g), urea (U), acetamide (A) or formamide (F). With NaCl, KCl, M, G, E, g, U, and A, tubules shrunk osmometrically within 0.5 sec and remained shrunk for as long as 20 sec without recovering their original volume (sometimes A showed some recovery). PST barely shrunk with F and quickly recovered their original volume. The permeability coefficients were 0 microns/sec (NaCl, M, g, E and U), 1 micron/sec (A), 84 microns/sec (F) and 0.02 micron/sec (G). The reflection coefficients sigma = 1.0 (NaCl, KCl, M, G, E, g and U), 0.95 (A) and 0.62 (F). Similar sigma values were obtained by substituting 200 mOsm/kg M in MBS by either NaCl, KCl, G, E, g, U, a or F. The olive oil/water partition coefficients are 5 (M), 15 (U), 85 (A) and 75 (F) (all x 10(-5)). Thus, part of F permeates the cell membrane through the lipid bilayer. The probing molecules van der Waals diameters are 7.4 x 8.2 x 12.0 (M), 3.6 x 5.2 x 5.4 (U), 3.8 x 5.2 x 5.4 (A) and (3.4 x 4.5 x 5.4 (F) A.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Additional dolabellane diterpenes from the Caribbean gorgonian octocoral Eunicea laciniata.

The Caribbean gorgonian octocoral Eunicea laciniata from the coasts of Palomino Island, Puerto Rico, has yielded four known and five new diterpenes based on the dolabellane ring system. The structures of the novel compounds 3-7 were established by interpretation of their spectral data. Some of these new compounds showed weak cytotoxicity against HeLa cells.

Animals↗
PubMed1995

Fibronectin (FN) decreases glomerular lesions and synthesis of tumour necrosis factor-alpha (TNF-alpha), platelet-activating factor (PAF) and FN in proliferative glomerulonephritis.

We have studied the effect of therapy with plasma FN on glomerular synthesis of PAF, TNF-alpha and FN, in experimental proliferative glomerulonephritis. Glomerular PAF, TNF-alpha and FN production were increased in rats with nephritis. Peak glomerular PAF production preceded, while peak glomerular TNF-alpha bioactivity coincided with maximal proteinuria. Rats treated with FN (5 mg/kg per 48 h) for 15 days had less proteinuria, glomerular and interstitial cell infiltration and glomerular PAF, TNF-alpha and FN synthesis than non-treated rats. In order to characterize further the mechanisms of action of FN, healthy rats were injected with either FN or saline. Peripheral blood mononuclear cells and neutrophils from healthy rats injected with FN secreted less TNF-alpha and PAF, respectively, than those obtained from saline-treated rats. Our data suggest that the beneficial effect of FN may be related to decreased number of glomerular leucocytes and decreased synthesis of inflammatory mediators and extracellular matrix.

Animals↗
PubMed1995

Involvement of tumor necrosis factor-alpha in the pathogenesis of experimental and human glomerulonephritis.

The evidence supporting a role for TNF-alpha in glomerular diseases can be summarized with the following: TNF-alpha can be secreted in the kidney by intrinsic renal cells and infiltrating phagocytes, as has been shown in vitro and in vivo during glomerular injury. TNF-alpha has proinflammatory actions which include cell death, chemotactic properties, and modulation of secretion of other inflammatory mediators, and extracellular matrix (Fig 5). Administration of exogenous TNF-alpha or agents that induce release of endogenous TNF alpha, such as endotoxin, increase the severity of experimental glomerular injury. Furthermore, the blockade of TNF-alpha action with specific antibodies, soluble receptors, or inhibitors improves the outcome of glomerulonephritis. Finally, several of the agents currently in use for the therapy of glomerular injury, such as corticosteroids and cyclosporine, are known to modulate the production of TNF-alpha. Specific TNF-alpha antagonists or inhibitors may have a role in the management of glomerulonephritis in the future.

Animals↗
PubMed1995

[Airway continuous positive pressure in acute respiratory failure caused by Pneumocystis carinii pneumonia].

OBJECTIVE: To evaluate the efficiency of continuous positive airway pressure through a face mask in acute respiratory insufficiency (ARI) secondary to Pneumocystis carinii pneumonia. DESIGN: Prospective study. SETTING: Multidisciplinary ICU. PATIENTS: Fifteen patients with ARI secondary to Pneumocystis carinii pneumonia were studied. INTERVENTIONS: Initially al patients received high flow oxygen therapy through a face mask for 60 minutes (Pre-CPAP phase); then CPAP through a face mask, with identical FiO2 and for a similar period of time (Pst-CPAP phase). At the end of each phase the following parameters were evaluated: respiratory rate, heart rate, arterial gases, acid-base balance, and respiratory muscle motility. MEASUREMENTS: After oxygen therapy all fifteen patients had similar variables. After 60 minutes with CPAP through a face mask, significant improvements were noted for respiratory rate, heart rate, muscular effort, PaO2, SaO2, and PaO2/FiO2 (p < 0.001) in eleven patients, who survived after a mean stay of 8.5 days in the ICU with no evidence of major complications. In contrast, CPAP failed in four patients as respiratory rate, heart rate and vigorous muscle effort remained unchanged and, although PaO2 and SaO2 increased, the obtained values were significantly lower than in the remaining patients. Consequently, they underwent intubation and mechanical ventilation and after a mean stay of fourteen days with this ventilatory option died. CONCLUSIONS: These results confirm that CPAP through a face mask is an effective means to improve oxygenation in patients with Pneumocystis carinii pneumonia who develop hypoxemic respiratory insufficiency. Its early introduction in hospital protocols can help improving the prognosis in certain patients with severe PCP and avoid their admission to ICU, which would be thus preserved for those patients requiring mechanical ventilation.

Acute Disease↗
PubMed1994

Increase of tumour necrosis factor alpha synthesis and gene expression in peripheral blood mononuclear cells of children with idiopathic nephrotic syndrome.

The pathogenesis of idiopathic nephrotic syndrome (minimal change nephropathy and its variants) is not completely understood. In recent years it has been speculated that a cytokine released by circulating blood mononuclear cells could alter the permeability of the glomerular capillary wall. In this study we have explored the potential participation of tumour necrosis factor alpha (TNF alpha), a cytokine mainly produced by monocytes, in 25 children with idiopathic nephrotic syndrome. TNF alpha was determined by cytotoxicity bioassay in the L-929 cell line and by double antibody/RIA. Patients in activity had higher serum TNF alpha levels and TNF alpha production by monocytes than patients in remission and controls. TNF alpha mRNA expression in blood mononuclear cells was analysed by Northern blot. The TNF alpha mRNA levels in patients in activity were increased compared to controls and to patients in remission. No significant differences in IL-1 beta and IL-6 synthesis were found between patients and controls. Our results suggest that TNF alpha, but not other cytokines such as IL-1 beta and IL-6, could play a role in the pathogenesis of the proteinuria in idiopathic nephrotic syndrome.

Child↗
PubMed1994

Influence of pirenzepine on colonic serotonin changes induced by short chain fatty acid.

In this work we have demonstrated the influence of a short chain fatty acid (acetate) on the number of enterochromaffin (EC) cells containing serotonin (5HT), at two different pH (pH 6.9 absorptive stimuli, and pH 2.9 secretory stimuli), infused into the colon during one hour. The number of EC cells decrease significatively, specially in the cecum with a solution of low pH (2.9). The action of piprenzepine in preventing this reduction demonstrated that was partly mediated by a cholinergic receptor mechanism. On the other hand, a decrease on the release of 5HT to the lumen was a observed under the influence of pirenzepine. We conclude that the short chain fatty acid acetate, at a low pH induces the release of serotonin through a cholinergic mechanisms indicated by the inhibition observed with antimuscarinic drug.

Acetates↗
PubMed1994

[Anemia associated with acute post streptococcal glomerulonephritis].

Thirty-three children with post-streptococcal acute glomerulonephritis, age mean: 8.3 years (range: 6 - 12) were studied prospectively. Mean initial hematocrit (Hct) was 31.6% with 90% showing Hct under the normal lower limit for this age group. Reticulocyte index (RI) was < 0.5 in half of the cases. Serum iron concentration, total iron binding capacity (TIBC) and percentage of transferrin saturation were normal for this age group although 75% of the children had increased serum ferritin levels. At the time of discharge, Hct increased to 35.1% but 44% still had anemia. Hct increased spontaneously for 105 days stabilizing at 38%. Based on Hct changes, 3 groups were defined: Group I (3 individuals): normal upon discharge; Group II (19): partial recovery at discharge, slow recovery stabilizing after 105 days; Group III (11): lower Hct, slower recovery but with RI significantly higher than group II (0.96 vs 0.45 p < 0.01). Our data suggest that although hemodilution is present in all, it may be considered the solely factor only in 3 cases (Group I). In group II, evidence of bone marrow depression was indicated by the low RI. On the other hand, the intense anemia that could not be justified only by hemodilution and marrow depression in group III, suggests other pathogenic factors.

Acute Disease↗
PubMed1992

Aggregation of human polymorphonuclear leukocytes by endothelin: role of platelet-activating factor.

The mechanisms by which endothelin-1 (ET-1) acts on polymorphonuclear leukocytes (PMN) are insufficiently known. In this study, we assessed the hypotheses that ET-1 is a PMN-aggregating agent, and that platelet-activating factor (PAF) is the principal mediator of ET-1-induced PMN aggregation. ET-1 induced dose-related PMN aggregation, which started 1 min after ET-1 exposure. Two different specific PAF receptor antagonists blocked the effect of ET-1 on PMN aggregation. In addition, ET-1 induced a significant increase in the production of PAF by PMN after 2 to 5 min of ET-1 incubation. ET-1 induced PAF release from PMN rather than accumulation. This PAF production was dependent on intra- and extracellular Ca2+. In this regard, the PAF receptor antagonists significantly blunted the ET-1-induced peak in cytosolic free Ca2+ ([Ca2+]i). Our results, therefore, indicate that ET-1 is effective in causing aggregation of human PMN and that its action appears to be mediated by PAF production via a Ca(2+)-dependent mechanism.

Azepines↗
PubMed1992

Involvement of platelet-activating factor and tumour necrosis factor in the pathogenesis of joint inflammation in rabbits.

We have studied the participation of platelet-activating factor (PAF) in antigen-induced arthritis in rabbits, as well as the possible co-operation between PAF and tumour necrosis factor (TNF) in their ability to induce joint inflammation when injected into the knees of healthy rabbits. The administration of two structurally different PAF receptor antagonists, BN52021 and Alprazolam, from 4 h before the intra-articular injection of ovalbumin in preimmunized rabbits, induced an important reduction in the synovial fluid volume, in the amount of cells infiltrating the articular cavity and the synovial membrane, as well as in the prostaglandin E2 (PGE2) concentration. Furthermore, proteoglycans of the articular cartilage, which were found diminished in animals with non-treated arthritis, were well preserved in rabbits treated with PAF antagonists. All the synovial fluids from joints with arthritis had detectable amounts of PAF. The injection of either TNF or PAF into the joints of normal rabbits induced a mild inflammation. When TNF was administered 1 h before PAF, a synergistic response was noted in the synovial fluid volume, in the accumulation of leucocytes, and in the amount of PGE2. The administration of BN50726, a hetrazepine with a potent PAF-receptor antagonist effect, induced a diminution in those parameters. Our results suggest that PAF may be an early and important mediator of joint damage, and that TNF can amplify the inflammatory response induced by PAF. PAF receptor antagonists could play some role in the treatment of inflammatory joint diseases.

Animals↗
PubMed1992

Therapeutic effects of hidrosmin on chronic venous insufficiency of the lower limbs.

A double-blind, placebo-controlled trial was carried out to assess the effectiveness of a new synthetic bioflavonoid, hidrosmin, in patients with chronic venous insufficiency of the lower limbs. Fifty-seven patients, showing varicose veins and ankle swelling and suffering from local pain and heaviness of the legs, were allocated at random to receive treatment for 45 days with 1 capsule 3-times daily of either 200 mg hidrosmin (30 patients) or placebo (27 patients). Pain and heavy legs were assessed using rating scales; swelling was assessed by a photographic method. The results showed that hidrosmin produced a significant clinical improvement in all of the parameters evaluated; compared with placebo, there was a marked reduction in the main subjective symptoms accompanied by a 10% reduction in swelling. Apart from 1 patient who complained of epigastric pain, there were no reports of adverse events during the study period.

Adult↗
PubMed1992

[Puerperal uterine involution: an echographic follow-up].

We have studied 87 puerperal women during the first month postpartum. They were liable to ultrasound on the first, second and third day of this period. Eighteen of them were examined on the 15th and 30th day. The measure of the uterine area (pi x 1/2 length x 1/2 width) is seen as the most sensible method for this evaluation. The uterus involutionated symmetrically and in thirty days complete this process. They were no significative differences appreciated in the uterine involution that depends on the lactation, parity and the use of uterine retractors.

Adolescent↗
PubMed1991

The C-terminal domain of plant catalases. Implications for a glyoxysomal targeting sequence.

A castor bean (Ricinus communis cv. Hale) cDNA encoding catalase was cloned and sequenced. The cDNA encoding the carboxy-terminal domain of catalase was compared to the corresponding sequences of six other plant catalases. The deduced amino acid sequences were compared according to the chemical attributes of each amino acid within each carboxy-terminal domain. A tripeptide sequence having the chemical attributes of the peroxisomal targeting sequence [Gould, S.J., Keller, G.-A., Hosken, N., Wilkinson, J. & Subramani, S. (1989) J. Cell Biol. 108, 1657-1664] was common to all the glyoxysomal/peroxisomal plant catalases. This sequence motif was located six amino acids from the carboxy terminus of each of the plant catalases. An identical motif was also found within the carboxy-terminal domain of three mammalian catalases previously sequenced. We hypothesize that these motifs are at least part of the targeting mechanism for catalase entry into plant glyoxysomes/peroxisomes.

Amino Acid Sequence↗