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M Cano

Publications and source records attributed to M Cano.

At least 55 records · Page 3Linked to original sources
PubMed1995

Na(+)-H(+) exchange activity in brush-border membrane vesicles isolated from chick small intestine.

This study was undertaken to investigate the presence of a Na(+)-H(+) antiporter in brush-border membrane vesicles (BBMV) isolated from chick small intestine. An outwardly directed proton gradient (pH 5.5 inside, 7.5 outside) stimulated Na+ uptake into BBMV and resulted in a transient accumulation. No accumulation was observed in the absence of a proton gradient. Voltage clamping the membrane with K+ and valinomycin decreased the Na+ overshoot. Amiloride inhibited pH gradient-driven Na+ uptake in a dose-dependent manner with an IC50 of 44 microM. The relationship between pH gradient-driven Na+ uptake and external Na+ concentration followed simple, saturating Michaelis-Menten kinetics. Eadie-Hofstee analysis of the pH gradient-driven Na+ uptake indicated a single transport system with a Vmax of 33 nmol/mg protein per 15 s and a Km for Na+ of 12 mM. The initial rate of pH-driven Na+ uptake increased as the intravesicular pH decreased, with a Hill coefficient close to 1. These findings indicate that BBMV isolated from chicken small intestine possess a Na(+)-H(+) exchanger. This exchanger does not appear to be the one involved in cell pH regulation.

Amiloride↗
PubMed1995

Establishment and characterization of a new, spontaneously immortalized, pancreatic ductal cell line from the Syrian golden hamster.

Spontaneously immortal pancreatic cell lines are not available. By use of a defined culture medium, such a line (TAKA-1) was established from the Syrian golden hamster. Cytological, cytogenetic, molecular biological, enzymatic and receptor patterns as well as antigenicity were studied and were compared with those of the normal hamster pancreatic ductal cells in vivo. TAKA-1 cells grew exponentially in a monolayer on collagen gel in a defined medium but did not proliferate in soft agar. Ultrastructurally, the cells closely resembled the normal hamster pancreatic ductal cells. Similarities and dissimilarities were found between the normal ductal cells and TAKA-1 cells. Similarities included the presence of cytokeratin, carbonic anhydrase and some tumor-associated antigens. However, unlike the normal ductal cells, TAKA-1 cells expressed blood group A antigen and anti-vimentin, showed affinity to selected lectins, and an abnormality of chromosome 3, which is suggested to be associated with immortality. Moreover, unlike the hamster pancreatic ductal cancer cells but like the normal hamster pancreatic ductal cells, TAKA-1 cells did not have a c-Ki-ras mutation. EGF, TGF-alpha and secretin, but not CCK or GRP, bound to the TAKA-1 cells. TAKA-1 cells produced TGF-alpha, and their growth was stimulated by exogenous EGF in serum-free medium. This cell line presents a suitable model for biologic and pathologic study of the hamster pancreatic ductal cells in vitro.

Animals↗
PubMed1995

An in vitro model for endothelial permeability: assessment of monolayer integrity.

An essential component of any in vitro model for endothelial permeability is a confluent cell monolayer. The model reported here utilizes primary human umbilical vein endothelial cells (HUVEC) cultured on recently developed polyethylene terephthalate micropore membranes. Using a modification of the Wright-Giemsa stain, confluent HUVEC monolayers grown on micropore membranes were routinely assessed using light microscopy. Determination of confluence using this method was confirmed by scanning electron microscopy. Transendothelial electrical resistance of HUVEC monolayers averaged 27.9 +/- 11.4 omega.cm2, 10 to 21% higher than literature values. Studies characterizing the permeability of the endothelial cell monolayer to 3H-inulin demonstrated a linear relationship between the luminal concentration of 3H-inulin and its flux across HUVEC monolayers. The slope of the flux versus concentration plot, which represents endothelial clearance of 3H-inulin, was 2.01 +/- 0.076 x 10(-4) ml/min (r2 = .9957). The permeability coefficient for the HUVEC monolayer-micropore membrane barrier was 3.17 +/- 0.427 x 10(-6) cm/s with a calculated permeability coefficient of the HUVEC monolayer alone of 4.07 +/- 0.617 x 10(-6) cm/s. The HUVEC monolayer reduced the permeability of the micropore membrane alone to 3H-inulin (1.43 +/- 0.445 x 10(-5) cm/s) by 78%. Evans blue dye-labeled bovine serum albumin could not be detected on the abluminal side without disruption of the HUVEC monolayer. These results demonstrate a model for endothelial permeability that can be extensively assessed for monolayer integrity by direct visualization, transendothelial electrical resistance, and the permeability of indicator macromolecules.

Cell Membrane Permeability↗
PubMed1995

Effects of sodium ascorbate, sodium saccharin and ammonium chloride on the male rat urinary bladder.

Sodium saccharin administered at high doses to male rats beginning after 5 weeks of age produces mild urothelial hyperplasia but does not result in a significant increase in incidence of bladder cancer unless it is administered after an initiating agent. However, if it is administered in a two-generation bioassay, a significant incidence of bladder tumors is produced. The hyperplastic and tumorigenic effects are inhibited by co-administration with high doses of NH4Cl. The present experiment was designed to evaluate the effects of another sodium salt, sodium ascorbate, administered through the neonatal time period. Sodium saccharin administered as 5% of the diet produced urothelial hyperplasia and increased labeling index, and this was inhibited by co-administration with 1.23% NH4Cl. Four doses of sodium ascorbate was evaluated. The lowest dose, 0.91%, was without effect on the urinary tract. A slight effect (not statistically significant) was observed at a dose of 2.73%, and a significant proliferative response was detected at 4.56 and 6.84%. Recent studies suggest that a calcium phosphate-containing amorphous precipitate forms in the urine of rats fed high doses of sodium saccharin, producing cytotoxicity of the urothelium and consequent regenerative hyperplasia. This precipitate was observed in the present experiment in the rats administered the high dose of sodium saccharin or the higher doses of sodium ascorbate. Formation of this precipitate and induction of urothelial proliferation were inhibited by co-administration of NH4Cl, but somewhat higher doses of ammonium chloride were required for doses of sodium ascorbate compared to sodium saccharin. These results demonstrate that sodium ascorbate administered through the neonatal time period of the male rat produces urothelial hyperplasia in the dose responsive manner, with a no-effect level of 0.91% of the diet. The formation of the calcium phosphate-containing amorphous precipitate and urothelial proliferation were inhibited by co-administration with NH4Cl.

Ammonium Chloride↗
PubMed1995

Differences in molecular biological, biological and growth characteristics between the immortal and malignant hamster pancreatic cells.

We compared morphological, biological and molecular biological patterns of a newly established, spontaneously immortalized pancreatic ductal cell line, TAKA-1, with a hamster pancreatic ductal adenocarcinoma cell line, PC-1. PC-1 cells grew in a monolayer on plastic tissue culture flasks, whereas TAKA-1 cells required type I collagen gel matrix to propagate. The growth rate and argyrophilic nuclear organizer region (Ag-NOR) counts were greater in PC-1 cells than in TAKA-1 cells. More TAKA-1 cells were in G0/G1 and less were in the S cell cycle phase than PC-1 cells. Karyotypically, the consistent change in TAKA-1 cells was an abnormal no. 3 chromosome, whereas additional chromosomal abnormalities were found in PC-1 cells. Ultrastructurally, TAKA-1 cells formed ductal structures and were composed of two types of cells, as in the normal hamster pancreatic ducts, whereas PC-1 cells were pleomorphic, showed evidence for loss of differentiation and contained intracytoplasmic lumens. Unlike the PC-1, TAKA-1 cells did not show a point mutation at codon 12 in the c-Ki-ras oncogene and did not grow in soft agar. Receptor binding assay showed specific epidermal growth factor binding to both cell lines, but secretin binding only to TAKA-1 cells. Both cells produced and released transforming growth factor-alpha in serum-free medium. Both cell lines expressed blood group A antigen, carbonic anhydrase, coexpressed cytokeratin and vimentin, and reacted with tomato and Phaseolus vulgaris leucoagglutinin (L-PHA) lectins. The results demonstrate that chromosomal abnormalities, cell cycle patterns, expression of cytokeratin 18, lectin bindings and the c-Ki-ras mutation are the features that distinguish the benign from the malignant pancreatic ductal cells in Syrian hamster.

Adenocarcinoma↗
PubMed1995

Effect of indomethacin on N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide-induced urinary tract carcinogenesis.

The effects of indomethacin on the urinary bladder and renal pelvis in rats treated with N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) were studied. Two hundred female Sprague-Dawley rats were divided into four groups. Group 1 received control diet without added chemicals. Group 2 was treated with indomethacin (1 mg/kg per day) in the drinking water throughout the experiment. Groups 3 and 4 received 0.2% FANFT in the diet for seven weeks followed by control diet. In addition to FANFT, Group 4 received indomethacin, 1 mg/kg per day, for the entire experiment. The rats were sacrificed after 92 weeks. There were no urothelial tumors in the control group, one renal pelvic tumor in the indomethacin group, 4 tumors in the FANFT group and 10 urothelial tumors in the FANFT + indomethacin group. The difference between Groups 3 and 4 was statistically significant (P < 0.05). Moderate and severe hyperplasia of the renal pelvic and papillary epithelium was found in 15 of 48 rats in Group 2 (indomethacin only) as compared with 6 of 49 control rats (P < 0.05). Moderate and severe hyperplasia was equally frequent in Groups 3 and 4 (14 and 17 animals in each group, respectively). Twenty-four rats in Group 2 had mammary tumors as compared to 12 animals in Group 1 (P < 0.01). Five of the tumors in Group 2 were adenocarcinomas. There was no difference between the number of mammary tumors in Groups 3 and 4 (36 and 32 animals in each group, respectively). The results suggest that indomethacin enhances FANFT-induced urinary tract carcinogenesis. Indomethacin also seems to exert some tumorigenic activity in the mammary gland.

Animals↗
PubMed1995

Effect of sodium saccharin on the neonatal rat bladder.

In a two-generation bioassay, high doses of dietary sodium saccharin (NaSac) produce bladder carcinoma in rats, whereas acid saccharin (HSac) does not effect the urothelium. NaSac and HSac administered as 5% of the diet to F0 Sprague-Dawley (SD) and F344 rats, continued through to the weaned male rats for ten additional weeks. Control 3H-thymidine labeling index (LI) was high prior to and at birth (approximately 11%), declining rapidly by weaning (to < 0.2). Neither NaSac nor HSac increased proliferation through 7 days of age. NaSac increased the proliferation rate at later times, whereas HSac did not. The LI decreased to control levels in NaSac-fed rats switched to control diet after weaning and increased in control-fed rats switched to NaSac after birth or weaning. In a second experiment, 5% NaSac did not affect urothelial morphology of SD rats through 7 days. By 21 days post-birth, urothelial hyperplasia occurred in NaSac-fed rat. The LI in treated versus control was similar through gestation, with a slight difference by 7 days. LI was significantly different by 21 days post-birth, but was similar between males and females. These results provide additional evidence for the increased cell proliferative effects of NaSac during the neonatal period, but not during gestation.

Animals↗
PubMed1995

[Coronary angioplasty in patients with restenosis. Characterization of clinical and angiographic profiles, hospital clinical course, and implications for the selection of patients].

PURPOSE: To define the clinical and angiographic profile of patients undergoing to a 2nd or a 3rd coronary angioplaty (PTCA) for the treatment of restenosis, and assess the safety and efficacy of redilatation. METHODS: Patients submitted to PTCA for a 1st (1stRE) or a 2nd (2ndRE) restenosis, from Jan/1980 through Dec/1993, were retrospectively identified, and compared to those undergoing to PTCA for de novo lesions (DN). RESULTS: A total of 5,736 underwent to dilatation of primary lesions, 610 of a 1stRE, and 64 of a 2ndRE. Patients with restenotic lesions had a higher prevalence of diabetes, smoking, history of prior infarction (1stRE e 2ndRE) and hyperlipidemia (2ndRE) as compared with primary lesions (p < 0.05). Besides patients with a 2ndRE had a higher incidence of left ventricular dysfunction, as compared to those with DN or a 1stRE (31.3% with EF < 45% in group 2ndRE, vs 19.8% and 23.1% in groups 1stRE and DN, respectively, p < 0.05). Primary success, infarct rate and mortality were similar in all groups, but emergency bypass surgery was significantly higher in the DN (2.1% vs 0.8% in 1stRE and 0% in 2ndRE, p < 0.05). CONCLUSION: Restenosis can be effectively treated by redilatation. Patients with clinical and angiographic features predisposing to further recurrence can be better treated with other interventions (i.e., coronary stents, bypass surgery).

Angioplasty, Balloon, Coronary↗
PubMed1994

Kinetics of the chloride-anion exchanger of brush-border membrane vesicles isolated from chicken jejunum.

The kinetic parameters of the apical Cl(-)-anion exchanger of chicken jejunum have been evaluated using brush-border membrane vesicles. SITS inhibited pH gradient-driven Cl- uptake in a dose-dependent manner with a IC50 of 700 microM. In the presence of a pH gradient (pH 7.7 inside, 5.5 outside), Cl- uptake tends to saturate with increasing external Cl- concentration. With 5 mM SITS the relationship between 36Cl- uptake and external Cl- concentration was linear. SITS-insensitive Cl- uptake may represent a diffusion component and has an apparent diffusion constant, Kd, of 0.068 +/- 0.002 nmol/mg protein per 15 s per mM. Eadie-Hofstee analysis of the data obtained by subtracting the SITS-insensitive component from the total uptake indicates a single transport system with a Km of 5 +/- 0.9 mM. A 50 mM outwardly directed bicarbonate gradient increased the Vmax from 3.63 +/- 0.33 to 6.40 +/- 0.54 nmol/mg protein per 15 s. The initial rate of H2-DIDS-sensitive Cl- uptake increased as the intravesicular pH increased, with a Hill coefficient greater than one. An intra- to extravesicular gradient of Cl-, I- and HCO3- stimulated Cl- uptake in the absence of a pH gradient.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1994

A comparison of the effects of sodium saccharin in NBR rats and in intact and castrated male F344 rats.

High doses of sodium saccharin (NaSac) increase proliferation in the bladder of the rat, with a male preponderance. The possibility that alpha 2u-globulin is involved in its mechanism of action was evaluated by feeding it at 7.5% of the diet to NCI-Black-Reiter (NBR) male rats, which do not synthesize liver-derived alpha 2u-globulin. NaSac affected urinary parameters similarly in F344 and NBR male rats, but NBR rats consumed more water leading to greater urinary volume. NaSac produced less proliferation in NBR than in intact F344 rats, with intermediate changes in castrated F344 males, which had intermediate urinary alpha 2u-globulin levels.

Alpha-Globulins↗
PubMed1994

Mitogenic effects of propoxur on male rat bladder urothelium.

Propoxur produces bladder tumors in rats, but not other species. The hyperplastic and tumorigenic effects do not occur if urinary pH is lowered by administering propoxur in a semi-synthetic diet or co-administering it with ammonium chloride (NH4Cl). We fed propoxur at 8000 p.p.m. in Altromin 1321 diet to male Wistar rats for 4 weeks, with or without NH4Cl as 10,000 p.p.m. of the diet. The urine of rats fed control diet with or without propoxur had a relatively high urinary pH (approximately 8); the addition of NH4Cl lowered the urinary pH by approximately 0.5-1.0 units. There was no evidence of urinary calculi or amorphous precipitate nor was there an increase in microcrystals or formation of different crystals than occur in normal rat urine. Propoxur produced hyperplasia of the urothelium, as observed by light and scanning electron microscopy, and increased the labeling index for proliferating cell nuclear antigen. These effects were significantly inhibited by co-administration with NH4Cl. There was no evidence of urothelial necrosis. Thus, the hyperplasia appears to result from a direct mitogenic effect of propoxur or a metabolite on the urothelium, rather than from toxicity and consequent regeneration. Based on the present study and previous investigations, the urothelial effects of propoxur in the rat are dependent on high urinary pH and high administered doses, factors which need to be incorporated into any mechanistic model for the chemical and into any extrapolation to potential effects in humans.

Animals↗
PubMed1994

Technetium-99m-red blood cell scintigraphy in the localization of nonenteric hemorrhage.

Rapid detection and localization of the bleeding site(s) are important factors in successful management of actively bleeding patients. Technetium-99m-red blood cell imaging is a sensitive, noninvasive modality commonly used for localization of gastrointestinal bleeding. Outside the gastrointestinal tract, experience with this technique has been limited. In this report, we present three cases of nonenteric bleeding successfully located using 99mTc red blood cells. The current literature regarding the scintigraphic localization of nonenteric bleeding is reviewed and discussed.

Aged↗
PubMed1993

[Lipid profile of hyperandrogenic women undergoing treatment with ketoconazole and its relationship with the evolution of the hormone pattern].

BACKGROUND: Previous studies have demonstrated changes in the lipidic profile following treatment with ketoconazole. However, the possible influence in patients with hyperandrogenism treated with this drug and its possible relation with the evolution of the hormonal pattern is unknown. RESULTS: Thirty-seven women with no tumoral hyperandrogenism treated with ketoconazole for 9 months (400 mg/day) were studied during treatment and one month after suppression of the medication. The study included the evaluation of total cholesterol, HDL cholesterol, triglycerides, LDL cholesterol and hormonal determinations of estradiol, androstenedione, testosterone, dehydroepiandrosterone, sulphate and sex hormone binding globulin. RESULTS: A rapid and significant decrease of LDL cholesterol and total cholesterol was observed (p < 0.01) which was reversible upon discontinuation of treatment. The HDL cholesterol levels and triglycerides did not modify. The final hormonal profile was more favorable with a significant reduction of testosterone and dehydroepiandrosterone sulphate (p < 0.01) and an increase in estradiol (p < 0.01). No statistical correlation was observed between the changes of sexual steroids and the changes in the lipidic pattern. CONCLUSIONS: In patients with non tumoral hyperandrogenism treated with ketoconazole the modifications of the steroid hormone profile do not appear to be related with changes in lipidic metabolism.

Adolescent↗
PubMed1993

Modification of antigen expression in human and hamster pancreatic cancer cell lines induced by sodium butyrate.

The effects of sodium butyrate (NaB) on the growth, morphology, and expression of blood group A, Lewis(a), and CA 19-9 antigen in the hamster pancreatic cancer cell lines, PC-1 (well differentiated) and PC-1.0 (poorly differentiated), and of blood group A, DU-PAN-2, and CA 19-9 antigens in four human pancreatic cancer cell lines, HPAF and CD11 (well differentiated) and CD18 and PANC-1 (poorly differentiated), were examined. NaB inhibited the growth of all cell lines and induced cell enlargement, an increase in secretory material, microfilaments, and pseudopodia. NaB stimulated the production of blood group A antigen in PC-1.0 cells dose dependently, but no change in the expression of this antigen was observed in the human cell lines. However, NaB treatment increased the presence of cells positive for CA 19-9 in PANC-1 but not in the remaining cell lines, none of which reacted with the anti-CA 19-9 antibody before or after NaB treatment. Untreated PANC-1 cells did not produce either blood group A or DU-PAN-2 antigen, but expressed these antigens after NaB treatment in a dose-dependent manner. The results suggest that NaB stimulates the differentiation of the hamster and human pancreatic cancer cell lines and increases or induces the expression of some tumor-associated antigens.

ABO Blood-Group System↗
PubMed1993

Chloride transport in brush-border membrane vesicles from chick jejunum.

This study sought to characterize the mechanism(s) of Cl- transport across brush-border membrane vesicles (BBMV) isolated from chick jejunum. An inwardly directed proton gradient stimulated chloride (36Cl-) uptake. This uptake was inhibited by SITS and H2-DIDS. pH-gradient-stimulated Cl- uptake was electroneutral, since it was only slightly decreased by voltage clamping the BBMV with K+ and valinomycin. An outwardly directed HCO3- gradient significantly increased chloride uptake in the presence of a pH gradient. pH-driven chloride uptake was reduced by the presence of several anions in the uptake buffer. The rank order of potency for inhibition of pH-driven Cl- uptake was Cl- > SCN- > HCO3- > I- > Glu- > HPO4(2-). In the absence of a pH gradient, chloride was less concentrated inside the vesicles than outside. Chloride uptake under these conditions was stimulated by a positive electrical potential inside the vesicles. This stimulation was inhibited by the addition of several anions outside the vesicles. The order of inhibitory potency was SCN- > I- > Cl- > HCO3- > Glu- > HPO4(2-). The results are consistent with the presence of a Cl-/base exchanger and a chloride conductance pathway in the brush-border membrane of chick small intestine.

Animals↗