Reduction of obstruction related bladder overactivity by the guanylyl cyclase modulators BAY 41-2272 and BAY 60-2770 alone or in combination with a phosphodiesterase type 5 inhibitor.

AIMS: To assess the urodynamic effects of soluble guanylyl cyclase (sGC) stimulator, BAY 41-2272, and activator, BAY 60-2770, (which both are able to induce cGMP synthesis even in the absence of nitric oxide (NO)) alone or in combination with a phosphodiesterase type 5 (PDE5) inhibitor, vardenafil, in a model of partial urethral obstruction (PUO) induced bladder overactivity (BO). METHODS: Fifty-six male Sprague-Dawley rats were used, 31 of them underwent PUO. Fourteen rats were used for Western blots to assess PDE5 and sGC expression. For drug evaluation cystometry without anesthesia was performed three days following bladder catheterization. RESULTS: Obstructed rats showed higher micturition frequency and bladder pressures than non-obstructed animals (Intermicturition Interval, IMI, 2.28 ± 0.55 vs. 3.60 ± 0.60 min (± standard deviation, SD); maximum micturition pressure, MMP, 70.1 ± 8.0 vs. 48.8 ± 7.2 cmH2O; both P < 0.05). In obstructed rats vardenafil, BAY 41-2272, and BAY 60-2770 increased IMI (2.77 ± 1.12, 2.62 ± 0.52, and 3.22 ± 1.04 min; all P < 0.05) and decreased MMP (54.4 ± 2.8, 61.5 ± 11.3, and 51.2 ± 6.3 cmH2O; all P < 0.05). When vardenafil was given following BAY 41-2272 or BAY 60-2770 no further urodynamic effects were observed. PDE5 as well as sGC protein expression was reduced in obstructed bladder tissue. CONCLUSIONS: Targeting sGC via stimulators or activators, which increase the levels of cGMP independent of endogenous NO, is as effective as vardenafil to reduce urodynamic signs of BO. Targeting the NO/cGMP pathway via compounds acting on sGC might become a new approach to treat BO.

Algunas consideraciones sobre las particularidades de la investigación científica en medicina / Some Observations on the Particularities of Scientific Research in Medicine

Se abordan ciertas particularidades de la investigación científica en medicina. Se relacionan algunos de los criterios que son necesarios para seleccionar y definir correctamente un tema de la investigación y se muestra como sólo mediante un enfoque holístico del problema científico, del objetivo general de la investigación y del experimento es posible precisar un tema. Debido al carácter dialéctico e integrador del proceso de investigación científica es imprescindible un primer acercamiento en forma conjunta antes de enunciar el tema de investigación de forma definitiva

Certain particularities of the scientific research in medicine are approached. Some of the criteria needed to select and define correctly a research topic are mentioned, and how only by means of from a holistic view of the scientific problem, and the main research objective and of the general experiment, it is possible to find a subject. Due to dialectic and integrating character of the scientific investigation process, it is essential to approach the subject in a collectiveway, before the subject topic of the research be enunciated definitively

Algunas consideraciones sobre las particularidades de la investigación científica en medicina / Some Observations on the Particularities of Scientific Research in Medicine

Se abordan ciertas particularidades de la investigación científica en medicina. Se relacionan algunos de los criterios que son necesarios para seleccionar y definir correctamente un tema de la investigación y se muestra como sólo mediante un enfoque holístico del problema científico, del objetivo general de la investigación y del experimento es posible precisar un tema. Debido al carácter dialéctico e integrador del proceso de investigación científica es imprescindible un primer acercamiento en forma conjunta antes de enunciar el tema de investigación de forma definitiva.

Certain particularities of the scientific research in medicine are approached. Some of the criteria needed to select and define correctly a research topic are mentioned, and how only by means of from a holistic view of the scientific problem, and the main research objective and of the general experiment, it is possible to find a subject. Due to dialectic and integrating character of the scientific investigation process, it is essential to approach the subject in a collectiveway, before the subject topic of the research be enunciated definitively.

Adenovirus-mediated p53 gene transfer in advanced non-small-cell lung cancer.

BACKGROUND: Preclinical studies in animal models have demonstrated tumor regression following intratumoral administration of an adenovirus vector containing wild-type p53 complementary DNA (Ad-p53). Therefore, in a phase I clinical trial, we administered Ad-p53 to 28 patients with non-small-cell lung cancer (NSCLC) whose cancers had progressed on conventional treatments. METHODS: Patients received up to six, monthly intratumoral injections of Ad-p53 by use of computed tomography-guided percutaneous fine-needle injection (23 patients) or bronchoscopy (five patients). The doses ranged from 10(6) plaque-forming units (PFU) to 10(11) PFU. RESULTS: Polymerase chain reaction (PCR) analysis showed the presence of adenovirus vector DNA in 18 (86%) of 21 patients with evaluable posttreatment biopsy specimens; vector-specific p53 messenger RNA was detected by means of reverse transcription-PCR analysis in 12 (46%) of 26 patients. Apoptosis (programmed cell death) was demonstrated by increased terminal deoxynucleotide transferase-mediated biotin uridine triphosphate nick-end labeling (TUNEL) staining in posttreatment biopsy specimens from 11 patients. Vector-related toxicity was minimal (National Cancer Institute's Common Toxicity Criteria: grade 3 = one patient; grade 4 = no patients) in 84 courses of treatment, despite repeated injections (up to six) in 23 patients. Therapeutic activity in 25 evaluable patients included partial responses in two patients (8%) and disease stabilization (range, 2-14 months) in 16 patients (64%); the remaining seven patients (28%) exhibited disease progression. CONCLUSIONS: Repeated intratumoral injections of Ad-p53 appear to be well tolerated, result in transgene expression of wild-type p53, and seem to mediate antitumor activity in a subset of patients with advanced NSCLC.

Improved antitumor activity of cis-Bis-neodecanoato-trans-R,R-1,2- diaminocyclohexaneplatinum (II) entrapped in long-circulating liposomes.

Cis-bis-neodecanoato-trans-R, R-1,2-diaminocyclohexaneplatinum (II) (NDDP) has previously been formulated in conventional liposomes and shown to be nonnephrotoxic in humans, not cross-resistant with cisplatin in different in vitro and in vivo systems, and more active than cisplatin against murine models of experimental liver metastasis. The activity was attributed to the avid uptake of liposomes by the liver. To extend to the treatment of solid tumors outside the liver, NDDP was formulated, in this study, in long-circulating liposomes composed of egg phosphatidylcholine (PC), cholesterol (Chol) and polyethyleneglycol conjugated to phosphatidylethanolamine (PEG-PE). In vitro, PC/Chol/NDDP liposomes were barely toxic to murine melanoma cells B16-F0 (IC50 = 195.6 microM) as evaluated by tetrazolium dye colorimetric assay. Inclusion of PEG3000-PE into PC/Chol/NDDP liposomes significantly enhanced their cytotoxicity to a level that was comparable to that of DMPC/DMPG/NDDP liposomes (7.3 vs. 7.9 microM). Biodistribution study indicated that PC/Chol/PEG3000-PE/NDDP liposomes could preferentially localize in s.c. melanoma in C57BL/6 mice. PC/Chol/PEG3000-PE/NDDP liposomes were much more efficient in inhibiting tumor growth in vivo than free cisplatin, free NDDP or NDDP formulated in liposomes of other lipid composition. Compared with cisplatin, the in vivo toxicities of PC/Chol/PEG3000-PE/NDDP liposomes were also significantly reduced. Furthermore, if the tumor was treated with local hyperthermia after injection of PC/Chol/PEG3000-PE/NDDP liposomes, the tumor uptake of liposomes increased by 60%. The tumor inhibitory effect of PC/Chol/PEG3000-PE/NDDP was also significantly improved when combined with local hyperthermia.

Enhanced therapeutic effect against liver W256 carcinosarcoma with temperature-sensitive liposomal adriamycin administered into the hepatic artery.

The antitumor activity of Adriamycin encapsulated in temperature-sensitive liposomes combined with local hyperthermia (HT) was tested in rats bearing well-developed liver W256 carcinosarcoma tumors. Two h after rats received Adriamycin encapsulated in temperature-sensitive liposomes via either the hepatic artery (i.a.) or the femoral vein (i.v.) or free Adriamycin i.a., liver HT was applied at 42 degrees C for 6 min. In animals treated with liposomal Adriamycin i.a., HT resulted in a 38% reduction in the tumor volume ratio and a 2.2-fold increase in the life span of the animals. In animals treated with liposomal Adriamycin i.v. or free Adriamycin i.a., HT did not alter the tumor volume ratio or life span of the animals. Administration i.a. of liposomal Adriamycin markedly increased the tumor drug levels (4-14-fold), reduced the systemic distribution of the drug, and slowed the drug decrease from both the tumor and liver compared with animals treated i.v.. Liver HT in animals treated with liposomal Adriamycin i.a. further increased tumor drug levels by 1.5-2.6-fold, further slowed the drug decrease from the tumor, and resulted in a dissociation of the parallel decrease of drug and lipid from the tumor. This latter effect was not observed in the other groups. These pharmacological findings combined with the lack of beneficial effect from HT in animals treated with free Adriamycin i.a. or liposomal Adriamycin i.v. suggest that i.a. administration of Adriamycin encapsulated in temperature-sensitive liposomes results in a significant retention of intact liposomes in the tumor vasculature that are able to release the encapsulated drug into the tumor cell compartment upon raising the temperature to the phase transition level.

Preclinical toxicity and pharmacology of liposome-entrapped cis-bis-neodecanoato-trans-R,R-1,2-diaminocyclohexane platinum(II).

Liposome-entrapped cis-bis-neodecanoate-trans-R,R-1,2-diaminocylohexane platinum(II) (L-NDDP) is a new lipophilic cisplatin derivative formulated in a liposomal carrier currently in phase I clinical trials. The preclinical toxicity and pharmacology of L-NDDP were studied in mice and dogs. At the LD50 dose (i.v. bolus) in mice (60.5 mg/kg or 181.5 mg/m2), a tenfold decrease in the granulocyte and platelet counts was observed in the absence of renal toxic effects. In dogs, the maximum tolerated dose (MTD) of L-NDDP given i.v. over a period of 45-60 min was 150 mg/m2. This dose produced significant vomiting (6-18 episodes), minimal renal dysfunction, a maximal decrease in granulocyte and platelet counts of from 30% to 70%, and acute and transient elevation of liver enzymes. Higher doses (225 and 300 mg/m2) resulted in severe gastrointestinal (GI) toxicity in one animal and the death of two others within 48 h. Autopsy results showed multifocal hemorrhages in the lungs, GI tract, kidney, and liver. Three dogs were treated monthly with the MTD up to a cumulative dose of 637.5-712.5 mg/m2 with excellent tolerance. No cumulative myelosuppression or liver dysfunction was observed, whereas a slight increase in the creatinine baseline level was detected in all three animals. Autopsy results at the end of the study showed mild changes limited to the liver, kidney, and GI tract. Pharmacologic studies showed that the drug was cleared, fitting a two-compartment model with a mean t1/2 alpha of 7.1 min and a t1/2 beta of 87.8 h. These studies show that L-NDDP can safely be given at therapeutic doses to animals and that the dose-limiting toxic effects consists of myelosuppression in mice and a multiorgan hemorrhagic syndrome related to vascular injury in dogs.

Toxicity and antitumor activity of cis-bis-carboxylato(trans-R,R-1,2-diaminocyclohexane) platinum(II) complexes entrapped in liposomes.

A new series of highly lipid-soluble cis-bis-carboxylato(trans-R,R-1,2-diaminocyclohexane)platinum(II) complexes were synthesized and characterized by their elemental analysis and by various spectroscopic techniques [infrared (IR), 195pt nuclear magnetic resonance (NMR)]. cis-bis-Neopentanoato(trans-R,R-1,2-diaminocyclohexane)platinum(II ) (NPDP), cis-bis-neodecanoato(trans-R,R-1,2-diaminocyclohexane)-platinum(II ) (NDDP), and cis-bis-n-decanoato(trans-R,R-1,2-diaminocyclohexane)-platinum(II) (DEDP) complexes were entrapped in multilamellar vesicles composed of dimyristoyl phosphatidylcholine (DMPC) and dimyristoyl phosphatidylglycerol (DMPG) at a 7:3 molar ratio and tested for toxicity and antitumor activity. The entrapment efficiency of the liposomal platinum (L-Pt) complexes (L-NPDP, L-NDDP, L-DEDP) was greater than 95%, and the stability in 0.9% NaCl solution at 4 degrees C was greater than 95% at day 14 in each case. The LD50 values of L-NPDP, L-NDDP, and L-DEDP when injected i.v. were 30, 54, and 150 mg/kg, respectively. L-NPDP, L-NDDP, and L-DEDP had no significant nephrotoxicity [as evidenced by a lack of elevated blood urea nitrogen (BUN) levels]. The percentages of T/C obtained after a single i.p. injection of the optimal dose of L-NPDP, L-NDDP, and L-DEDP tested against L1210 leukemia were 175%, 187%, and 212%, respectively [160% for cisplatin (CDDP)]. When a multiple i.p. injection schedule was used (on days 1, 5, and 9), L-NPDP, L-NDDP, and L-DEDP were more active than CDDP (percentage of T/C: 312%, 312%, 277%, and 220%, respectively). When injected i.v., only L-NDDP showed significant activity against L1210 leukemia i.v. (percentage of T/C: 186%). L-NDDP and L-DEDP were markedly active against L1210 leukemia resistant to CDDP (percentage of T/C: 200% and 145% vs 112% for CDDP). L-NPDP, L-NDDP, and L-DEDP also had good activity against i.p. B16 melanoma when they were injected i.p. on days 1, 5, and 9 (percentage of T/C: 206%, 225%, and 306%, respectively). L-NDDP and L-DEDP were more effective than CDDP in inhibiting the growth of liver metastases of murine M5076 reticulosarcoma, whereas L-NPDP was not active. The results obtained to date suggest that L-NDDP is the best L-Pt-complex candidate for further developmental studies.

Retractile mesenteritis involving the colon: barium enema, sonographic, and CT findings.

Retractile mesenteritis is a rare disorder characterized by either focal or diffuse thickening of the mesentery due to chronic inflammation and fibrosis. Six cases are reported in which stenosis of the colon, an uncommon complication of retractile mesenteritis, was the predominant radiologic finding. Diagnosis was suggested by the tapered, serrated appearance of the stenotic segment on barium enema complemented by the findings on sonography and CT.