Evidence that PAR-1 and PAR-2 mediate prostanoid-dependent contraction in isolated guinea-pig gallbladder.

We have investigated the ability of protease-activated receptor-1 (PAR-1), PAR-2, PAR-3 and PAR-4 agonists to induce contractile responses in isolated guinea-pig gallbladder. Thrombin, trypsin, mouse PAR-1 activating (SFLLRN-NH(2)) peptide, and mouse PAR-2 activating (SLIGRL-NH(2)) and human PAR-2 activating (SLIGKV-NH(2)) peptides produced a concentration-dependent contractile response. Mouse PAR-4 activating (GYPGKF-NH(2)) peptide, the mouse PAR-1 reverse (NRLLFS-NH(2)) peptide, the mouse PAR-2 reverse (LRGILS-NH(2)) and human PAR-2 reverse (VKGILS-NH(2)) peptides caused negligible contractile responses at the highest concentrations tested. An additive effect was observed following the contractile response induced by either trypsin or thrombin, with the addition of a different PAR agonist (SFLLRN-NH(2) and SLIGRL-NH(2), respectively). Desensitization to PAR-2 activating peptide attenuated the response to trypsin but failed to attenuate the response to PAR-1 agonists, and conversely desensitization to PAR-1 attenuated the response to thrombin but failed to alter contractile responses to PAR-2 agonists. The contractile responses produced by thrombin, trypsin, SFLLRN-NH(2) and SLIGRL-NH(2) were markedly reduced in the presence of the cyclo-oxygenase inhibitor, indomethacin, whilst the small contractile response produced by NRLLFS-NH(2) and LRGILS-NH(2) were insensitive to indomethacin. The contractile responses to thrombin, trypsin, SFLLRN-NH(2) and SLIGRL-NH(2) were unaffected by the presence of: the non-selective muscarinic antagonist, atropine; the nitric oxide synthase inhibitor, L-NAME; the sodium channel blocker, tetrodotoxin; the combination of selective tachykinin NK(1) and NK(2) receptor antagonists, (S)-1-[2-[3-(3,4-dichlorphenyl)-1 (3-isopropoxyphenylacetyl) piperidin-3-yl] ethyl]-4-phenyl-1 azaniabicyclo [2.2.2] octane chloride (SR140333) and (S)-N-methyl-N-[4-acetylamino-4-phenylpiperidino-2-(3, 4-dichlorophenyl)-butyl] benzamide (SR48968), respectively. The results indicate that PAR-1 and PAR-2 activation causes contractile responses in the guinea-pig gallbladder, an effect that is mediated principally by prostanoid release, and is independent of neural mechanisms.

Effect of several bicyclic peptide and cyclic pseudopeptide tachykinin NK2 receptor antagonists in the human isolated ileum and colon.

The affinities of the monocyclic pseudopeptides MEN10,508, MEN10,573, MEN10,581, MEN10,612, MEN10,619 and MEN10,677, and the bicyclic peptides MEN10,627, MEN10,692, MEN10,771, MEN10,882 and MEN10,993 were evaluated at the tachykinin NK2 receptors of the human isolated ileum and colon circular muscle preparations, by using [betaAla8]neurokinin A(4-10) as an agonist. All of the antagonists tested produced a concentration-dependent and competitive antagonism of [betaAla8]neurokinin A(4-10)-mediated contractions in both preparations. MEN10,612 (pKB = 8.1) and MEN10,627 (pKB = 8.4-8.8) were among the most potent analogs within their chemical classes. In general, the bicyclic peptide antagonists were more potent than the monocyclic peptide compounds, showing a nanomolar affinity for the human NK2 receptor. By comparing the affinities shown by the antagonists under study at NK2 receptors of the human gut with the affinities measured at NK2 receptors of the rabbit isolated pulmonary artery and hamster isolated trachea, a high degree of pharmacological homology was found between human and rabbit NK2 receptors. The present results point out the class of NK2 receptor antagonists bearing a bicyclic peptide structure, like MEN10,627, as candidates for testing in pathological conditions characterized by exaggerated gut motility, in which tachykinins might play a role as non-cholinergic excitatory neurotransmitters.

Effect of nepadutant at tachykinin NK(2) receptors in human intestine and urinary bladder.

We have characterized the action of the tachykinin NK(2) receptor antagonist nepadutant (c¿[(beta-D-GlcNAc)Asn-Asp-Trp-Phe-Dpr-Leu]c(2 beta-5 beta)¿) in the human isolated ileum, colon and urinary bladder. Nepadutant (30-1000 nM) competitively antagonized neurokinin A- or [beta Ala(8)]neurokinin A-(4-10)-induced contractions in all tissues, with pK(B)=8.3 (ileum and colon) and pK(B)=8.5 (bladder). In contrast, the nonpeptide tachykinin NK(2) receptor antagonist SR 48968 (or (S)-N-methyl-N [4-acetylamino-4-phenylpiperidino)-2-(3, 4-dichlorophenyl) butyl] benzamide) (30-1000 nM) produced insurmountable antagonism in all preparations. The tachykinin NK(2) receptor blockade produced by nepadutant in the colon was fully reversed by washout, whereas that produced by SR 48968 was not. Nepadutant (1 microM) greatly reduced (by 70-80%) the nonadrenergic noncholinergic (NANC) contractile off-response evoked by electrical field stimulation in the human ileum, and almost abolished it in the presence of the tachykinin NK(1) receptor antagonist GR 82334 (or: [[(S,S) Pro-Leu (spiro-gamma-lactam)](9,10),Trp(11)]Physalaemin (1-11)) (1 microM). The present results show that nepadutant is a potent, competitive and reversible antagonist at human tachykinin NK(2) receptors and provide further evidence that tachykinins act as excitatory NANC neurotransmitters in the human small intestine.

[Intrathoracic omentoplasty in the treatment of pleural cavity secondary to stabilized bronchial fistula]. / L'omentoplastica intratoracica nella cura del cavo pleurico secondario a fistola bronchiale stabilizzata.

AIM: The aim of this paper was to verify the effectiveness of omentoplasty, either single or associated to other procedures, in the treatment of permanent fistula of the main bronchi. METHODS: The authors report their experience of 10 intrathoracic omentoplasties for pleural cavity from fistula of the main bronchus. In 2 cases a single omentoplasty was performed, while 8 patients had an associated procedure (4 thoracoplasties, 7 mioplasties and 2 mammoplasties). In 8 cases the vascular pedicle used for the omentum was the right gastroepiploic artery, and the left one in the remaining 2 patients. The omentum was mobilized through an opening in the diaphragm and anchored to the bronchial stump. In the combined plasties it was then covered by chest wall (thoracoplasty), muscles (mioplasty) or mammary gland (mammoplasty); in the single omentoplasty omentum was also sutured to the chest wall. Indication for combined procedures was high bacterial contamination of the pleural cavity; single omentoplasty was performed for small cavities, where other procedures had previously failed. Only in the single omentoplasties a pre-operative selective angiography of the gastroepiploic arteries was performed. RESULTS: Such procedures were resolutive in 9 patients; 1 needed an endoscopic application of fibrin glue. CONCLUSION: Intrathoracic omentoplasty is an effective procedure to solve both pleural cavity and stabilized bronchial fistula, mostly because of plastic and immunologic features of the omentum.

Mucinous adenocarcinoma in chronic anorectal fistula.

Adenocarcinoma in association with chronic anal fistula is a rare disease which gives rise to difficult problems of diagnosis and treatment. A case of mucinous adenocarcinoma arising on a long standing fistula in ano is described. A patient with a long history of mucinous discharge, pain and perianal induration underwent a biopsy of the external opening of the fistula that showed mucinous infiltrating adenocarcinoma. After a colonoscopy and a preoperative abdominal CT scan, she underwent a successful abdominoperineal resection with adjuvant chemoradiation therapy. Diagnosis of this condition is often difficult; deep and multiple biopsies of the fistulous tracks or perianal mass are necessary to establish the diagnosis. An accurate staging of the neoplasm, using endorectal ultrasound, NMR or CT scans is needed to plan the appropriate treatment. Recent studies have shown that locally advanced anal adenocarcinomas could benefit from pre or postoperative chemoradiation therapy. However, an accurate and complete removal of the tumor, which usually entails abdominoperineal resection, is often necessary to achieve radicality. Despite new therapy protocols, the prognosis of mucinous adenocarcinoma is still poor, mostly due to its advanced nature at the time of diagnosis. This reinforces the importance of biopsy of all perianal abscesses and fistulas for early detection and treatment.

[Laparoscopic appendectomy versus open appendectomy in suspected acute appendicitis in female patients]. / Appendicectomia laparoscopica versus appendicectomia aperta nel sospetto di appendicite acuta in pazienti di sesso femminile.

INTRODUCTION: The aim of the study is to analyse the own data and try to discuss if laparoscopic appendectomy offers any advantages in treating young women suffering from pain in right lower abfdominal quadrant. MATERIALS AND METHODS: The study was conducted on 148 patients admitted from October 1993 to December 1998 with diagnosis of of pain in right iliac fossa and operated on with a laparoscopic (LA group: 75 cases) or open approach (OA group: 73 cases). Patients were prospectively randomized on the surgical approach adopted, following a randomized list. RESULTS: The operative time in LA group was significantly (p < 0.001) longer (87.2 minutes) than for OA group (65.2 minutes). In 2 patients (2.7%) the operation had to be converted. Diagnosis had remained unknown in 16 patients (21.9%) of OA group, in spite of only one case (1.4%) with laparoscopic technique. We didn't observed intraoperative complications. Pain in the first and second postoperative days, evaluated on the use of pain medication, was significantly less in patients in group LA (p < 0.01). There were no deaths. Postoperative complications occurred in 4 patients (5.5%) of group LA, and in 8 patients (10.9%) of group OA. Hospital stay was significantly shorter for those having laparoscopic appendectomy (p < 0.001). DISCUSSION: The main advantages of laparoscopic appendectomy consist more in diagnostic accuracy, than in less postoperative pain, less hospital stay and less postoperative complications. CONCLUSION: Laparoscopic appendectomy is a safe and accurate approach.

[Colonic pouch versus direct colo-anal anastomosis in the reconstruction after total resection of the mesorectum: review of the literature]. / Pouch colica versus anastomosi colo-anale diretta nella ricostruzione dopo resezione totale de mesoretto: revisione della letteratura.

Good results in terms of control of the disease and 5 years survival have encouraged the use of the sphincter-saving technique for the treatment of cancers of the lower rectum. However, after this operation a percentage of patients complains of functional abnormalities such as increased bowel frequency and modification of continence especially within 12-18 months after surgery. This review analyzes the results of coloanal anastomosis following rectal excision trying to evaluate if the construction of a colonic pouch allows to limit or to prevent the functional anorectal abnormalities that usually follow a straight colo-anal anastomosis.

Oxidation of methyl- and ethyl- tertiary-butyl ethers in rat liver microsomes: role of the cytochrome P450 isoforms.

Methyl t-butyl ether (MTBE) and ethyl t-butyl ether (ETBE) are commonly used in unleaded gasoline to increase the oxygen content of fuel and to reduce carbon monoxide emissions from motor vehicles. This study was undertaken to investigate: (1) the effect of administration to rats of ETBE and its metabolite, t-butanol, on the induction and/or inhibition of hepatic P450 isoenzymes; (2) the oxidative metabolism of MTBE and ETBE by liver microsomes from rats pretreated with selected P450 inducers and purified rat P450(s), (2B1, 2E1, 2C11, 1A1). ETBE administration by gavage at a dose of 2 ml/kg for 2 days induced hepatic microsomal P4502E1-linked p-nitrophenol hydroxylase and the P4502B1/2-associated PROD and 16beta-testosterone hydroxylase, verified by immunoblot experiments. t-Butanol treatments at doses of 200 and 400 mg/kg i.p. for 4 days did not alter any liver microsomal monoxygenases. Both MTBE and ETBE were substrates for rat liver microsomes and were oxidatively dealkylated to yield formaldehyde and acetaldehyde, respectively. The dealkylation rates of both MTBE and ETBE were increased c. fourfold in phenobarbital (PB)-treated rats. In rats pretreated with pyrazole, an inducer of 2E1, only the demethylation of MTBE was increased (c. twofold). When the oxidations of MTBE and ETBE were investigated with purified P450(s) in a reconstituted system, it was found that P4502B1 had the highest activities towards both solvents, whereas 1A1 and 2C1 were only slightly active; P4502E1 had an appreciable activity on MTBE but not against ETBE. Metyrapone, a potent inhibitor of P450 2B, consistently inhibited both the MTBE and ETBE dealkylations in microsomes from PB-treated rats. Furthermore, 4-methylpyrazole (a probe inhibitor of 2E1) and anti-P4502E1 IgG showed inhibition, though modest, only on MTBE demethylation, but not on ETBE deethylation. Inhibition experiments have also suggested that rat 2A1 may exert an important role in MTBE and ETBE oxidation. Taken together, these results indicate that 2B1, when expressed, is the major enzyme involved in the oxidation of these two solvents and that 2E1 may have a role, although minor, in MTBE demethylation. The implications of these data for MTBE and ETBE toxicity remain to be established.

Radio-guided surgery in recurrent renal hyperparathyroidism: report of a case.

BACKGROUND: It has been demonstrated that radio-guided surgery offers several advantages in treating primary hyperparathyroidism. Even if it is considered less helpful in renal hyperparathyroidism, it could be of tremendous advantage in the treatment of persistent or recurrent secondary hyperparathyroidism. METHODS: We report a case of recurrent secondary hyperparathyroidism treated by the use of radio-guided surgery. The preoperative assessment consisting of ultrasonography, magnetic resonance imaging, and 99mTc-sestamibi scintigraphy identified a parathyroid in the upper mediastinum. The patient underwent a radio-guided neck re-exploration that allowed a rapid localization and excision of the ectopic gland, which was located in the anterosuperior mediastinum, in front of the trachea, between the innominant and the left common carotid artery. RESULTS: The operative time was 45 minutes. The patient was discharged on the first postoperative day. A decrease in serum calcium and parathyroid hormone was observed subsequently. A follow-up of 6 months did not show any recurrence. CONCLUSIONS: The case reported indicates that radio-guided surgery can help surgeons detect parathyroid tissue in selected cases of renal hyperparathyroidism.

Role of radio-guided surgery in recurrent secondary hyperparathyroidism.

BACKGROUND: The aim of this paper is to state the role of radio-guided surgery (RGS) in case of recurrent secondary hyperparathyroidism. METHODS: Two cases of recurrent secondary hyperparathyroidism were treated using RGS. After a preoperative assessment, which included ultrasonography (US), MRI and (99m)Tc-radiolabelled sestamibi scan, a radio-guided neck re-exploration was planned. On the day of surgery the patients underwent a radionuclide injection. After 90 min, surgery began. RESULTS: Dissection was guided by placing the probe in the wound to localize any increased concentration of radioactivity. In the first case the probe identified the gland located deeply in the right tracheo-esophageal groove; in the other case the probe detected a site of increased uptake in the upper mediastinum. Both lesions were dissected and excised; a frozen section confirmed they were parathyroid glands with diffuse hyperplasia. The operative time was less than 60 min in both cases. The patients were discharged on the first postoperative day. A decrease in serum calcium and PTH was observed subsequently. A minimum follow-up of 6 months did not show any recurrence. CONCLUSION: RGS can help in detecting the parathyroid tissue in selected cases of renal hyperparathyroidism and makes operation much easier and more predictable.

Comparison of prazosin, terazosin and tamsulosin: functional and binding studies in isolated prostatic and vascular human tissues.

BACKGROUND: Terazosin and tamsulosin are drugs currently used in the treatment of benign prostatic hypertrophy (BPH). The potency of these two alpha(1) receptor antagonists and that of prazosin to inhibit contractions induced by noradrenaline and the binding of [(3)H]-prazosin in human prostate and four different human arterial and venous vessels (saphenous and umbilical veins, renal and mesenteric arteries) was studied. METHODS: By bioassay and binding studies, we examined the receptor affinities of different alpha(1) receptor antagonists in different human tissues. RESULTS: pKb of terazosin, tamsulosin, and prazosin obtained in the prostatic tissues (8.15, 9.64, and 8.59, respectively) were not different from those obtained in the umbilical veins (8.07, 9.56, and 8.30, respectively), in the mesenteric artery (8.27, 10.29, and 9.01, respectively), renal artery (8.35, 10.13, and 8.76, respectively) and saphenous vein (7.8, 10.3, and 9.32, respectively). IC(50) (nM) of prazosin, terazosin, and tamsulosin obtained from binding studies in membrane preparations from prostate tissue were similar to those from umbilical veins, saphenous vein, and renal artery. CONCLUSIONS: All of the evaluated drugs showed similar selectivity for prostatic vs. vascular tissues. Thus, different clinical profiles of the present drugs should not result from their differential affinity for prostatic versus vascular alpha(1)-adrenoceptors.