External urology consultation quality at a third-level public hospital in Mexico.

INTRODUCTION: Patient satisfaction is the degree of conformity with the healthcare they receive. It is real evidence and one of the most important factors in determining the effectiveness and quality of healthcare systems. OBJECTIVE: To identify the quality of care in the Urology outpatient department of a third-level hospital. MATERIALS AND METHODS: The NHS (National Health Service) 2018 quality of care questionnaire with 11 sections, 133 items, and duration of approximately 25min was randomly administered to 250 patients attending Urology outpatients at a third-level public hospital in Mexico. RESULTS: According to responses, 92% (n=230) knew the reason for the consultation. 64.8% (n=162) had a consultation with the same physician by whom they were initially seen. The longest reported hospital wait time before being seen was more than 2h in 29.6% (n=74). As for consultation time, 212 patients responded and the duration was 11-20min in 52.8% (n=112). Finally, 33.2% (n=83) considered the quality of service to be good. CONCLUSIONS: The use of the NHS 2018 survey in the Urology service at a third-level public hospital in Mexico is feasible, since we managed to obtain a significant and continuous improvement in all its indicators which is satisfactory for all.

Mutations in the GTP-binding site of GS alpha alter stimulation of adenylyl cyclase.

Mutational replacements of specific residues in the GTP-binding pocket of the 21-kDa ras proteins (p21ras) reduce their GTPase activity. To test the possibility that the cognate regions of G protein alpha chains participate in GTP binding and hydrolysis, we compared signaling functions of normal and mutated alpha chains (termed alpha s) of Gs, the stimulatory regulator of adenylyl cyclase. alpha s chains were expressed in an alpha s-deficient S49 mouse lymphoma cell line, cyc-. alpha s in which leucine replaces glutamine 227 (corresponding to glutamine 61 of p21ras) constitutively activates adenylyl cyclase and reduces the kcat for GTP hydrolysis more than 100-fold. There is a smaller reduction in GTPase activity in another mutant in which valine replaces glycine 49 (corresponding to glycine 12 of p21ras). This mutant alpha s is a poor activator of adenylyl cyclase. Moreover, the glycine 49 protein, unlike normal alpha s, is not protected against tryptic cleavage by hydrolysis resistant GTP analogs; this finding suggests impairment of the mutant protein's ability to attain the active (GTP-bound) conformation. We conclude that alpha s residues near glutamine 227 and glycine 49 participate in binding and hydrolysis of GTP, although the GTP binding regions of alpha s and p21ras are not identical.

Liposome-based therapy of human ovarian cancer: parameters determining potency of negatively charged and antibody-targeted liposomes.

Liposomes containing cytotoxic agents may be highly efficacious for intracavitary therapy of malignancies such as ovarian carcinoma, which resides principally in the peritoneal cavity. We have examined in vitro the cytotoxicity of a variety of liposome-drug formulations against OVCAR-3, a human ovarian cancer cell line. Two drugs tested, methotrexate-gamma-aspartate and 5-fluoroorotate, show increased cytotoxicity on various cultured cell lines following encapsulation in liposomes and can be considered liposome-dependent agents. With the optimal lipid composition used in this study, the maximal increase in potency on OVCAR-3 is 2.6-fold for methotrexate-gamma-aspartate and 5.2-fold for 5-fluoroorotate. Studies on liposome-cell association suggest a low capacity of OVCAR-3 to bind and internalize phospholipid vesicles, which limits the in vitro potency of liposomes for these cells. OC-125, a monoclonal antibody recognizing an antigen common to a number of human ovarian cancers (CA-125), has been coupled covalently to the liposome surface. Liposomes bearing OC-125 and containing methotrexate-gamma-aspartate show an 8-fold increase in potency against OVCAR-3 cells in a 96-h growth inhibition assay. Briefer exposure of tumor cells to treatment accentuates the advantage of targeted liposomes. The cytostatic effect of 1 h exposure to OC-125 liposomes is 100-fold greater than the equivalent exposure to free drug and equal to the maximal cytostatic effect achieved with free drug for 96 h. Attachment of OC-125 antibody also confers upon liposomes the capacity to recognize OVCAR-3 cells growing as an ascites tumor in nude mice. After i.p. injection, control liposomes bind tumor cells in relatively low numbers, while fluorescent OC-125 liposomes can be observed bound specifically to tumor cell masses for periods of days.

Carboxyl terminal domain of Gs alpha specifies coupling of receptors to stimulation of adenylyl cyclase.

The alpha subunits of Gs and Gi link different sets of hormone receptors to stimulation and inhibition, respectively, of adenylyl cyclase. A chimeric alpha i/alpha s cDNA was constructed that encodes a polypeptide composed of the amino terminal 60% of an alpha i chain and the carboxyl terminal 40% of alpha s. The cDNA was introduced via a retroviral vector into S49 cyc- cells, which lack endogenous alpha s. Although less than half of the hybrid alpha chain is derived from alpha s, its ability to mediate beta-adrenoceptor stimulation of adenylyl cyclase matched that of the normal alpha s polypeptide expressed from the same retroviral vector in cyc- cells. This result indicates that carboxyl terminal amino acid sequences of alpha s contain the structural features that are required for specificity of interactions with the effector enzyme, adenylyl cyclase, as well as with the hormone receptor.

Antiproliferative and anticontractile effects of liposome encapsulated fluoroorotate.

Incorporation of fluoroorotate into liposomes increases its growth inhibitory potency for rabbit dermal fibroblasts 30-fold. The optimal lipid composition of the liposomes is dipalmitoylphosphatidylglycerol:cholesterol (67:33). Liposomes prepared by reverse phase evaporation without extrusion are the optimal liposomes for delivery. Fluoroorotate, like other RNA directed fluoropyrimidines, inhibits the contractility of rabbit dermal fibroblasts. The effect is greatest when the cells are exposed to the drug for the 48-72 hr immediately prior to measurement of cell contractility. Encapsulation of fluoroorotate increases its anticontractile potency 10-fold. The anticontractile effects of both free and encapsulated fluoroorotate on the cells last at least 12 days. Leakage studies suggest that the loss of drug from the liposomes under storage conditions will be quite low. Leakage studies also confirm that serum will accelerate the loss of drug from the liposomes and that sonicated liposomes leak much more rapidly than larger liposomes. However, the large difference between egg phosphatidylglycerol and dipalmitoylphosphatidylglycerol liposomes for drug delivery is not explained by leakage studies. These results suggest that encapsulated fluoroorotate may be a useful adjunct to surgery for treatment of proliferative vitreoretinopathy.

Clearance and localization of intravitreal liposomes in the aphakic vitrectomized eye.

The authors have examined the fate of intravitreally injected liposomes in the aphakic, vitrectomized eye of the rabbit. Liposomes labelled with 125[I]-p-hydroxybenzimidylphosphatidylethanolamine were eliminated rapidly from the intraocular fluid. Nonetheless, a significant fraction of these liposomes were found to bind to various ocular tissues including the retina, iris, sclera, and cornea. Ultrastructural studies with gold colloid-loaded liposomes revealed that retinal bound liposomes were attached to the inner limiting lamina but did not penetrate to the internal cells of the retina. Epiretinal cells bound and internalized gold colloid-loaded liposomes suggesting that these cells may be very sensitive to liposome mediated drug delivery.

Liposome-mediated delivery of pteridine antifolates to cells in vitro: potency of methotrexate, and its alpha and gamma substituents.

We have examined the growth-inhibitory potency of several pteridines encapsulated in negatively charged liposomes, including methotrexate, methotrexate-gamma-methylamide, methotrexate-gamma-dimethylamide, methotrexate-alpha-aspartate, and a lipophilic methotrexate-phosphatidylethanolamine conjugate. The potency of encapsulated methotrexate is greater than the potency of the free drug for CV1-P cells, but not for other cell lines. The potency of methotrexate-gamma-methylamide and methotrexate-gamma-dimethylamide is only minimally improved by encapsulation. The potency of methotrexate-alpha-aspartate is increased by encapsulation. In addition, the lipophilic methotrexate derivative has demonstrable potency when incorporated in liposomes. We have also examined the potency of several pteridines under conditions where the cells are exposed to the drug for periods shorter than the entire growth assay. Reduction of the exposure time decreases the potency of both encapsulated and free drugs. However, the difference in potency between the encapsulated and free drug is increased, because the potency of the encapsulated drug is affected less. Consequently, encapsulated methotrexate-gamma-aspartate is 300-fold more potent than free drug, if CV1-P cells are exposed to drug for 4 h. Moreover, encapsulated methotrexate is more potent than free methotrexate for growth inhibition of L929 fibroblasts, if the term of exposure is less than 8 h. Potency is least affected by reduction of exposure length for the lipophilic methotrexate derivative.

Fluoropyrimidine treatment of ocular cicatricial disease.

The authors have studied the antiproliferative and anticontractile effects of fluorouracil, fluorouridine, and fluorodeoxyuridine on rabbit dermal fibroblasts. All three drugs have antiproliferative effects, the order of their efficacy being fluorodeoxyuridine greater than fluorouridine greater than fluorouracil. In contrast, only fluorouridine and fluorouracil have anticontractile effects. Fluorouridine requires less time of exposure and has greater anticontractile effects than fluorouracil. Thymidine eliminates the antiproliferative effects of fluorodeoxyuridine, but has no effect on either the antiproliferative or anticontractile effects of fluorouracil and fluorouridine. These results suggest that the anticontractile effects of the fluoropyrimidines are caused by their incorporation into RNA and not by the inhibition of DNA synthesis. Metabolites of fluorouracil may provide enhanced control of cell proliferation and contractility in the management of ocular disorders such as proliferative vitreoretinopathy and glaucoma.

Immune response mediated by liposome-associated protein antigens. IV. Modulation of antibody formation by vesicle-encapsulated methotrexate.

Large unilamellar reverse-phase evaporation vesicles (REV) were used as a heterobifunctional carrier for a pharmacologically active agent and a protein antigen. Methotrexate (MTX) was encapsulated in the hydrophilic compartment of liposomal REV with or without surface-conjugated bovine serum albumin (BSA) antigen. The administration of MTX encapsulated within BSA-coated vesicles (MTX.REV-BSA) could either enhance or depress the anti-BSA plaque-forming cell (PFC) response in mice. On the other hand, the administration of MTX entrapped in plain vesicles (MTX.REV) produced essentially a suppressive effect on the PFC response stimulated by the simultaneous injection of a separate antigen, e.g. vesicle-conjugated BSA (REV-BSA). This suppression of the antibody response occurred, whether MTX.REV was injected 1 day before, during, or 1 day after the immunization with an antigen. These results indicate that liposome-encapsulation of a very limited drug dose can modify the immunobiological effect of the drug which, when presented in its free form at the same dose, exerts no appreciable action on the engendered immune response. Thus, the modulation of the immune response by a liposome-encapsulated drug appears to be influenced by the drug dose can modify the immunobiological effect of the drug which, when presented in its free form.

The effects of liposome size and surface charge on liposome-mediated delivery of methotrexate-gamma-aspartate to cells in vitro.

We have studied the liposome-mediated delivery of methotrexate-gamma-aspartate to five cell lines. The sensitivity of the cells to encapsulated drug varies widely in accordance with their ability to take up the liposomes. CV1-P cells can be 150-times more sensitive to encapsulated methotrexate-gamma-aspartate than to free drug, while AKR/J SL2 cells are only twice as sensitive to the encapsulated drug. Negatively-charged liposomes are much more efficient for delivery than are neutral liposomes, and cholesterol is an essential component of the liposome membrane for optimal drug delivery. The optimal liposome size for drug delivery is 0.1 micron, although the amount of cell-associated lipid is the same for all liposome sizes. The effect of the encapsulated drug is inhibited by NH4Cl, suggesting an endocytic mechanism for delivery. The potency of the encapsulated drug is not affected by wide variations in the drug: lipid ratio.

5-Fluoroorotate: a new liposome-dependent cytotoxic agent.

The potency of 5-fluoroorotate for inhibition of L929 or CV1-P cell growth is increased by encapsulation in negatively charged liposomes. The optimal liposome composition is dipalmitoylphosphatidylglycerol: cholesterol, 67:33. Unextruded large unilamellar liposomes are the optimal size for delivery. This compound is the second transport-negative drug which we have found to exhibit liposome-dependent delivery.

Modulation of membrane fusion by ionotropic and thermotropic phase transitions.

We have studied the relationship of ionotropic and thermotropic phase transitions to divalent cation induced fusion of large unilamellar phospholipid vesicles. Fusion was monitored by the Tb/dipicolinic acid fluorescence assay for the intermixing of internal aqueous contents of vesicles. The phase behavior of the membranes was followed by differential scanning calorimetry. (1) Sr2+ and Ba2+ shifted the phase transition temperature (Tc) of bovine brain phosphatidylserine vesicles from 6 to 27 and 31.5 degrees C, respectively. These cations induced vesicle fusion at temperatures above or below the Tc of that cation/phospholipid complex, indicating that an isothermal phase change from the liquid-crystalline to the gel phase is not a requirement for membrane fusion. (2) The temperature dependence of the initial rate of fusion of phosphatidylserine/dipalmitoylphosphatidylcholine (1:1) vesicles in the presence of Ca2+ exhibited a pronounced maximum at 17 degrees C, at the lower part of the broad phase transition endotherm whose Tc was about 25 degrees C; fusion was inhibited completely at 30 degrees C when the membrane was in the liquid-crystalline state. These observations suggest that molecular clusters rich in phosphatidylserine, formed when the membrane is in the phase transition region, allow the vesicles to fuse. (3) The fusion of phosphatidylserine/dimyristoylphosphatidylethanolamine (1:1) vesicles, whose Tc was also around 25 degrees C, had a different temperature dependence in that the initial rate increased sharply above the Tc, with a local maximum within the transition region. Phase separation of dimyristoylphosphatidylethanolamine was induced by Ca2+ but not by Mg2+, although both ions induced fusion.(ABSTRACT TRUNCATED AT 250 WORDS)