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Biomedical subjects

F Soler

Publications and source records attributed to F Soler.

At least 37 records · Page 2Linked to original sources
PubMed1996

Expression of retinoblastoma gene product (pRb) in mantle cell lymphomas. Correlation with cyclin D1 (PRAD1/CCND1) mRNA levels and proliferative activity.

Mantle cell lymphomas (MCLs) are molecularly characterized by bcl-1 rearrangement and constant cyclin D1 (PRAD-1/CCND1) gene overexpression. Cyclin D1 is a G1 cyclin that participates in the control of the cell cycle progression by interacting with the retinoblastoma gene product (pRb). Inactivation of the Rb tumor suppressor gene has been implicated in the development of different types of human tumors including some high grade non-Hodgkin's lymphomas. To determine the role of the retinoblastoma gene in the pathogenesis of MCLs and its possible interaction with cyclin D1, pRb expression was examined in 23 MCLs including 17 typical and 6 blastic variants by immunohistochemistry and Western blot. Rb gene structure was studied in 13 cases by Southern blot. Cytogenetic analysis was performed in 5 cases. The results were compared with the cyclin D1 mRNA levels examined by Northern analysis, and the proliferative activity of the tumors was measured by Ki-67 growth fraction and flow cytometry. pRb was expressed in all MCLs. The expression varied from case to case (mean, 14.1% of positive cells; range, 1.3 to 42%) with a significant correlation with the proliferative activity of the tumors (mitotic index r = 0.85; Ki-67 r = 0.7; S phase = 0.73). Blastic variants showed higher numbers of pRb-positive cells (mean, 29%) than the typical cases (10%; P < 0.005) by immunohistochemistry and, concordantly, higher levels of expression by Western blot. In addition, the blastic cases also had an increased expression of the phosphorylated protein. No alterations in Rb gene structure were observed by Southern blot analysis. Cyclin D1 mRNA levels were independent of pRb expression and the proliferative activity of the tumors. These findings suggest that pRb in MCLs is normally regulated in relation to the proliferative activity of the tumors. Cyclin D1 overexpression may play a role in the maintenance of cell proliferation by overcoming the suppressive growth control of pRb.

Aged↗
PubMed1996

Concentration-time profiles of oxytetracycline in blood, kidney and liver of tench (Tinca tinca L) after intramuscular administration.

Oxytetracycline (OTC) is a widely-used antibiotic in several animal species. The Food and Drug Administration allows OTC to be used in fish intended for human food, but there is limited kinetics data available. We studied OTC concentrations in plasma, kidney and liver in tenches (Tinca tinca L) after im administration using HPLC. Concentrations were fit to a monocompartment open model by extended least squares regression analysis using the MULTI (ELS) computer program. Peaks of OTC concentrations (Cmax) occurred at 4 h for blood and kidney and 72 h for liver and were 134.1 micrograms/mL, 129.8 micrograms/g and 333.4 micrograms/g, respectively. There was a high correlation (r = 0.9448) between blood and kidney concentrations and less between blood and liver. Concentrations were statistically different for each system. The blood OTC concentrations were higher than renal concentrations 92% of the time and were higher than hepatic concentrations 29% of the time. The plasma OTC half-life (21.2 h) was longer than in homeothermic species. The tench liver maintains considerable OTC residues and may affect food products derived from that organ.

Animals↗
PubMed1995

Functional properties of a sarcoplasmic reticulum Ca(2+)-ATPase with an altered Ca(2+)-binding mechanism.

Treatment of sarcoplasmic reticulum vesicles with diethylpyrocarbonate in the presence of a large excess of reagent, at pH 6.2 and at room temperature, reveals both a fast- and a slow-reacting population of protein residues. The loss of the Ca(2+)-ATPase activity is mainly associated with the fast-reacting population being partially sensitive to hydroxylamine. There is also an effect on the Ca(2+)-binding mechanism. Shorter derivatization times (5 min) produce a loss of the positive cooperativity of Ca2+ binding. When the treatment was prolonged for 30 min there was an additional decrease in the overall Ca2+ affinity. Curve-fitting procedures applied to the non-cooperative binding isotherms provide the equilibrium constants for the two Ca2+ sites, although they cannot discriminate between interacting and independent site mechanisms. Prestationary kinetics assays show 2 Ca2+:1 ATP ratios, at any extent of Ca2+ saturation, indicating that the Ca2+ sites are not independent. The Ca2+ dissociation profile after derivatization shows a decrease in the dissociation constant for the release of the second Ca2+, which is consistent with interacting sites. Isotopic exchange experiments show fast and slow components of equal amplitude even at subsaturating Ca2+ concentrations, which is incompatible with independent binding sites. The experimental data suggest a modification of the equilibrium binding constants making them more similar, but keeping the interacting character. The structural position of the external (cytoplasmic) and the internal (lumenal) Ca2+ sites remains unaltered in the absence of positive cooperativity.

Adenosine Triphosphate↗
PubMed1995

Drug action of ritodrine on the sarcoplasmic reticulum Ca(2+)-ATPase from skeletal muscle.

Ritodrine inhibits the steady-state Ca(2+)-ATPase activity of isolated sarcoplasmic reticulum vesicles in a dose-dependent manner. The observed K0.5 value for inhibition (approximately 3 mM) gives proof of a low-affinity interaction. Ritodrine also interferes with the steady-state Ca2+ transport ability decreasing the maximal rate without modification of the Ca2+ or ATP affinity for the enzyme. This is consistent with an absence of competition for the transport and the catalytic sites. Analysis of the catalytic and transport cycle shows that: (i) ritodrine inhibits the phosphorylation partial reaction. This is supported by pre-steady-state kinetic experiments of Ca2+ transport and also by the temperature dependence of the phosphoenzyme level. (ii) At high ritodrine concentrations the dephosphorylation step becomes rate-limiting. This is suggested by the biphasic profile (V-shape) of phosphoenzyme accumulation at different ritodrine concentrations. This was also confirmed by chase experiments of radioactive phosphoenzyme decomposition at steady state. These data reveal a complex pattern of inhibition involving two sites for interaction with low and high ritodrine concentrations. It is envisaged that ritodrine does not exert any direct effect on the smooth muscle sarcoplasmic reticulum Ca(2+)-ATPase when used in the treatment of preterm birth.

Adenosine Triphosphate↗
PubMed1994

Triterpene derivatives that block entry of human immunodeficiency virus type 1 into cells.

A series of triterpene compounds characterized by a stringent structure-activity relationship were identified as potent and selective inhibitors of human immunodeficiency virus type 1 (HIV-1) replication. Currently studied botulinic derivatives have 50% inhibitory concentrations (IC50) against HIV-1 strain IIIB/LAI in the 10 nM range in several cellular infection assays but are inactive against HIV-2. These compounds did not significantly inhibit the in vitro activities of several purified HIV-1 enzymes. Rather, they appeared to block virus infection at a postbinding, envelope-dependent step involved in the fusion of the virus to the cell membrane.

Antiviral Agents↗
PubMed1994

Radiosurgery of carotid-cavernous fistulae.

25 cases of carotid-cavernous fistulae (CCF) who underwent radiosurgery with a conventional gamma source from 1977 to 1992 are reported. 22 were low-flow, spontaneous CCFs and 3 were high flow fistulae which had undergone a previous trapping. The total dose delivered was 30 to 40 Gy. 91% to patients with low-flow CCF cured after radiosurgery in a mean time of 7.5 months, presenting improvement in a mean time of 2.3 months. Only one of the high-flow fistulae was cured. Follow-up period ranged between 14 years and 15 months (mean: 50 months). No recurrence was recorded in any case. While intravascular embolotherapy is the treatment of choice for high-flow fistulae, stereotactic radiosurgery may be the elective treatment for low-flow CCF.

Arteriovenous Fistula↗
PubMed1994

Interdependence of H+ and K+ fluxes during the Ca(2+)-pumping activity of sarcoplasmic reticulum vesicles.

The release of H+ during the oxalate-supported Ca2+ uptake in sarcoplasmic reticulum vesicles is kinetically coincident with the initial phase of Ca2+ accumulation. The Ca2+ uptake is increased and the H+ release is decreased in the presence of KCl and other monovalent chloride salts as expected for a H(+)-monovalent cation exchange. The functioning of the Ca(2+)-pump is disturbed by the presence of potassium gluconate and to a lesser extent, of choline chloride. These salts do not inhibit the ATPase activity of Ca(2+)-permeable vesicles, suggesting a charge imbalance inhibition which is specially relevant in the case of gluconate. Therefore, K+, and also Cl-, appear to be involved in secondary fluxes during the active accumulation of Ca2+. The microsomal preparation seems homogeneous with respect to the K(+)-channel, showing an apparent rate constant for K+ release of approximately 25 s-1 measured with the aid of 86Rb+ tracer under equilibrium conditions. A Rb+ efflux, sensitive to Ca(2+)-ionophore, can be also detected during the active accumulation of Ca2+. The experimental data suggest that both monovalent cations and anions are involved in a charge compensation during the Ca2+ uptake and H+ release. Fluxes of these highly permeable ions would contribute to cancel the formation of a resting membrane potential through the sarcoplasmic reticulum membrane.

Animals↗
PubMed1994

Current status of natural family planning in Granada (Spain).

In Spain the use of natural family planning (NFP) is limited. In Barcelona, CODIPLAN, an NFP planning center, has offered natural methods to potential users for a number of years. In Granada and Jaén, information provided by health professionals on fertility awareness is now gaining importance. In 1989, a seminar introduced NFP in Granada; the program has been very active since. Two courses were run for teachers and for health personnel, and we took part in the practical training of providers of alternative medical care through two programs organized by the University of Granada. We also gave talks on local radio and television programs, presented updating sessions at daycare centers, and gave health education classes at primary and secondary schools. The international seminar on NFP in March, 1992 was organized jointly by the University and the City Council. The proceedings will be published by the University of Granada. In 1990, under the scientific auspices of the Natural Family Planning Department at the Zaidin Medical Center, we started a program of training and follow-up for NFP users via an on-going seminar on NFP. In Granada and Jaén, NFP methods are now available to the general population and to health personnel.

Contraception↗
PubMed1994

Recruitment of pregnant women for self-examination of the postpartum return of fertility.

In our health center we use breastfeeding in teaching natural family planning (NFP) to mothers. Our objective is for the women to detect the signs of returning fertility before ovulation. Breastfeeding is a factor in amenorrhea. All pregnant women attending our health center are invited to follow our course on maternal education from the 7th month of pregnancy. We inform them of the factors that influence the return of fertility and the signs of returning fertility, and urge the women to attend a course from the 20th day after childbirth. Since the beginning of June we have had a 30% participation rate by new mothers in the postpartum course. We have observed a new or strengthened desire to breastfeed and to observe the signs of fertility.

Amenorrhea↗
PubMed1994

Stereotactic radiosurgery for the treatment of low-flow carotid-cavernous fistulae: results in a series of 25 cases.

25 patients with low-flow carotid-cavernous fistula (CCF) underwent radiosurgery between 1977 and 1992. 22 had spontaneous low flow fistulae and 3 traumatic high flow fistulae which had been previously treated with internal carotid trapping. The mean preoperative symptomatic period was 12.2 months (4-24 months). Fistulae were classified according to Barrow's classification. Type T was added for traumatic, high-flow fistulae with flow reduction after internal carotid trapping. 11 cases were of type B, 4 of type C, 7 of type D and 3 of type T. The target point for radiosurgery was calculated from selective internal or external carotid angiograms. Stereotactic radiosurgery was performed with a cobalt source, with 5- to 10-mm collimators. A total dose of 30-40 Gy was delivered in all cases, except 1 posttraumatic case in which the dose was 20 Gy. The follow-up period ranged between 14 years and 15 months (mean: 49.76 months). 20 of the 22 low flow fistulae (90.9%) completely closed in a mean period of 7.5 months (range: 2-20 months) after radiosurgery. Improvement of the symptoms began at a mean period of 2.37 months (range: 0.5-14 months). There were no recurrences, the follow-up period ranging between 14 years and 15 months. 100% of type B CCF closed after a mean period of 5.9 months, 75% of type C closed after a mean period of 12.66 months, and 85.7% of cases of type D closed after a mean period of 8.16 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriovenous Fistula↗
PubMed1992

Heterologous expression of the human potassium channel Kv2.1 in clonal mammalian cells by direct cytoplasmic microinjection of cRNA.

The cloned human delayed rectifying K+ channel Kv2.1 (drk1) was expressed in clonal mouse fibroblasts (L-cells) and rat basophilic leukemia cells (RBL-1) by direct cytoplasmic microinjection of complementary RNA (cRNA). Within six hours, cells microinjected with Kv2.1 cRNA expressed a large sustained outward current as determined from whole-cell patch-clamp recordings. Nearly 100% of cells injected with cRNA expressed outward current. Current density was 30-70 pA/pF when measured at a potential of +50 mV. Steady-state activation and inactivation parameters for Kv2.1 were similar when expressed in either L-cells or RBL-1 cells. These results are the first to demonstrate that functional ion channel proteins can be expressed in mammalian clonal cell lines by direct cytoplasmic microinjection of cRNA.

Animals↗
PubMed1992

The Ca2+ release channel in junctional sarcoplasmic reticulum: gating and blockade by cations.

1. By using a sarcoplasmic reticulum preparation containing feet structures and the 45Ca2+/filtration technique, the opening and closing response of the Ca(2+)-channel was studied. 2. Extravesicular Sr2+ can activate the channel even though this cation is less efficient than Ca2+ in stimulating the Ca2+ release. Higher Sr2+ concentrations display inhibitory action. 3. By studying the closing response high- and low-affinity cations can be distinguished, according to the concentration range required to exert their effect. 4. The synergistic behavior observed by combining high- and low-affinity blocking cations suggest that they interact through the same binding site. 5. The high-and low-affinity cations are noncompetitive blockers of the activating Ca2+ suggesting the existence of an inhibitory site which is different to the activating site.

Animals↗
PubMed1992

Morphometric, structural, and ultrastructural studies of tench (Tinca tinca L.) hepatocytes after copper sulfate administration.

A structural, ultrastructural, and morphometric study was made of the liver parenchyma of 12 adult tench (Tinca tinca, L.) subjected to acute experimental copper sulfate poisoning. The lesions observed were characterized by the accumulation in the cytoplasm of large amounts of hemoglobinemic pigment produced by intense hemolysis, initially in Kupffer cells and by the last stage of the experiment in hepatocytes. This process became increasingly severe, and culminated in the massive necrosis of large areas of liver parenchyma, which led to the death of tench 12 days after the start of the experiment.

Animals↗
PubMed1992

[Severe digestive hemorrhage of an unusual etiology. Visible isolated and bleeding esophageal vessels].

We describe two patients with massive upper gastrointestinal bleeding. The upper gastrointestinal endoscopy revealed jet haemorrhage in the distal portion of the esophagus, from a visible vessel, without esophageal mucosal damage. In both cases arteriography was performed, and did not show vascular malformations or fistulous points. The patients were successfully treated, one with endoscopic sclerosis and balloon tamponade, and the other with endoscopic sclerosis and transcatheter embolization through left gastric artery. For the time being we do not know the true importance of these findings, but we hope that other reports help us to understand the clinical and pathologic features of this vascular lesion, and the best therapeutic approach.

Adolescent↗
PubMed1991

Radiosurgical treatment of low flow carotid-cavernous fistulae.

The good results obtained by stereotactic radiosurgery in arteriovenous malformations has led the authors to expect similar results in low flow carotid-cavernous fistulae. In this paper, 20 cases who underwent radiosurgery with a conventional gamma source are presented. The total dose delivered was 36 to 40 Gy. 90% of the patients were cured after radiosurgery after a mean time of 7 months. Those presenting a mild improvement after a mean time of 2 months and those with a marked improvement after 4 months.

Adolescent↗