Smooth muscle

In the isolated bronchial preparation of the guinea-pig, nicotine induced a contraction but not a relaxation. The contractile response of the bronchial preparation to nicotine was inhibited by hexamethonium and d-tubocurarine but not influenced by atropine and tetrodotoxin. In the isolated tracheal preparation of the guinea-pig where nicotine stimulated nicotinic receptor in nervous tissues, the contractile response to nicotine as considerably accelerated by the treatment of the guinea-pig with egg-albumin, while the contractile response of the bronchial preparation to nicotine was not influenced by the same treatment. These results suggest that a possible site of action of nicotine in the isolated bronchial preparation is not on the nervous cells but on the smooth muscle cells. However, we could not rule out a contribution by chemical mediators released by nicotine in the contractile mechanisms in the bronchial preparation.

We identified a novel endogenous protein inhibitor of Na + /K + -ATPase having an apparent mol mass of 70 kDa in the cytosolic fraction of the smooth muscle. The IC 50 value of the inhibitor towards the enzyme was determined to be in the nanomolar range. Important ...

Effect of mitragynine, an indole alkaloid isolated from Thai medicinal plant kratom (Mitragyna speciosa), on electrically stimulated contraction was studied in the guinea-pig ileum. Mitragynine (1 nM - 3 μM) inhibited the ileum contraction elicited by electrical stimulation, and its pD2 value was 6.91 ± 0.04 (n = 5). Morphine (1 nM − 1 μM) also inhibited the electrically stimulated contraction in a concentration-dependent manner (pD2 7.68 ± 0.11; n = 5). Mitragynine was 10 fold less potent than morphine. Mitragynine (3–10 μM) did not show any effect on the smooth muscle contraction induced by acetylcholine or histamine. Naloxone (10–300 nM) reversed the inhibitory effect of mitragynine on electrically stimulated contraction. Furthermore, naloxone showed a shift of concentration-response curve of mitragynine to the right. There was no significant difference in the affinity of naloxone (i.e. pA2) in the presence of mitragynine or morphine. Mitragynine (3–10 μM) inhibited the naloxone-precipitated withdrawal contraction following a brief (5 min) exposure of the ileum to morphine. Tetrodotoxin (1 μM) and atropine (1 μM) inhibited the withdrawal contraction. The present results suggest that mitragynine inhibits the electrically stimulated contraction of guinea-pig ileum through the opioid receptor.

Multiple prospective Radiation Therapy Oncology Group (RTOG) protocols have evaluated bladder-preserving combined-modality therapy (CMT) for muscle-invasive bladder cancer (MIBC), reserving cystectomy for salvage treatment. We performed a pooled analysis of long-term outcomes in patients with MIBC enrolled across multiple studies. Four hundred sixty-eight patients with MIBC were enrolled onto six RTOG bladder-preservation studies, including five phase II studies (RTOG 8802, 9506, 9706, 9906, and 0233) and one phase III study (RTOG 8903). Overall survival (OS) was estimated using the Kaplan-Meier method, and disease-specific survival (DSS), muscle-invasive and non-muscle-invasive local failure (LF), and distant metastasis (DM) were estimated by the cumulative incidence method. The median age of patients was 66 years (range, 34 to 93 years), and clinical T stage was T2 in 61%, T3 in 35%, and T4a in 4% of patients. Complete response to CMT was documented in 69% of patients. With a medi...

The non-neuronal cholinergic system is widely expressed in human airways. Choline acetyltransferase (ChAT) and/or acetylcholine are demonstrated in more or less all epithelial surface cells (goblet cells, ciliated cells, basal cells), submucosal glands and airway smooth muscle fibres. Acetylcholine is also demonstrated in the effector cells of the immune system (lymphocytes, macrophages, mast cells). Epithelial, endothelial and immune cells express nicotinic and muscarinic receptors. Thus the cytomolecule acetylcholine can contribute to the regulation of basic cell functions via auto-/paracrine mechanisms (proliferation, differentiation, ciliary activity, secretion of water, ions and mucus, organization of the cytoskeleton, cell-cell contact). Acetylcholine also modulates immune functions (release of cytokines; proliferation, activation and inhibition of immune cells). Preliminary experimental evidence suggests that mucosal inflammation may be associated with raised acetylcholine le...

The objectives of these investigations were: (a) to make a preliminary study to assess concentration-depth profiles of mitomycin C (MMC) in the bladder wall at specified time intervals after passive diffusion (PD); and (b) to conduct a major study to compare concentration-depth profiles after PD and electromotive drug administration (EMDA) of MMC. Full thickness sections of viable human bladder wall were placed in two-chamber cells with urothelium exposed to donor compartments containing 40 mg of MMC in 100 ml of 0.96% NaCl solutions and with serosa-facing receptor compartments containing 0.9% NaCl solutions. In the preliminary study during each of nine experimental sessions, five sections of bladder wall were individually exposed to MMC for either 5, 15, 30, 45, or 60 min. In the major study, an anode and a cathode were sited in the donor and receptor compartments, and 14 paired experiments--current (20 mA)/no current--were conducted over a 30-min period. Bladder wall sections were...

[corrected] We investigated which nerve pathways are necessary to achieve ejaculation using penile vibratory stimulation (PVS) in men with spinal cord injury (SCI). Eight men with SCI were selected based on the presence of a bulbocavernosus reflex (BCR) and consistent antegrade ejaculation with PVS. Level of injury was cervical (4), upper thoracic (4), and lower thoracic (1). Mean age was 30.4 years (range 22 to 38). Usual responses to PVS included autonomic dysreflexia (4), erection (4), and consistent somatic responses such as abdominal contractions (8). Local anesthesia of the dorsal penile nerves (penile block) was achieved using 1% plain lidocaine injection. Effective penile block was confirmed by loss of the BCR. Two PVS ejaculation trials were performed: one trial during the penile block and one trial when the penile block had worn off. In 4 subjects, the bladder contents were analyzed for retrograde ejaculation. With the penile block, ejaculation was inhibited in 100% of the subjects. None of the bladder washings demonstrated sperm, indicating absence of retrograde ejaculation. None of the subjects exhibited their usual erectile response, somatic responses, or signs of autonomic dysreflexia. After the penile block wore off, PVS induced ejaculation in all subjects. If subjects usually had erection, somatic responses, or signs of autonomic dysreflexia, these also returned. Our data suggest that ejaculatory response to PVS in SCI men requires the presence of intact dorsal penile nerves.

PURPOSE Smad7 is a molecule that blocks the Smad2/3 signal. Herein, we examined the effects of Smad7 gene introduction on post-injury conjunctival wound healing in mice. Its effects on the cultured human subconjunctival fibroblasts (SCFs) were also investigated. METHODS A circumferential incision was made in the equatorial conjunctiva by using scissors in the right eye of fully anesthetized adult C57BL/6 mice (n=72). Smad7 cDNA-expressing adenoviral vector was topically applied. The control eye received nonfunctioning adenoviral vector. After 2, 5, 7, and 30 days the eyes were processed for histological or immunohistochemical examination to evaluate wound healing of conjunctiva. The expressions of type-I collagen and growth factors were evaluated by real time-reverse transcriptase-polymerase chain reaction. The effects of Smad7 gene introduction on the cultured human SCFs were also studied. RESULTS Marked Smad7 protein expression was detected in the vector-treated conjunctival epith...

To determine the long-term results of a bladder-sparing approach in the treatment of muscle-invasive bladder cancer. Ninety-four patients with invasive transitional cell carcinoma of the bladder were treated by transurethral resection followed by 2 or 3 cycles of cisplatin-based chemotherapy. Patients were then treated with 6480 cGy of radiation in 49 patients, segmental cystectomy in 8, or surveillance only in 7. Patients who failed to respond to chemotherapy or radiation therapy, or who developed recurrent muscle-invasive disease in follow-up, underwent salvage cystectomy. Patients were then carefully followed for a median follow-up of more than 5 years. After initial therapy, 53 patients (56%) were alive with their bladder preserved. Thirty of those 53 (57%) developed a local recurrence in follow-up. After a median follow-up of more than 5 years, the ultimate relapse-free survival is 49% (Stage T2, 84%; T3, 53%; and T4, 11%; P < 0.01). Of all patients enrolled, 53% had bladder preservation; however, of the currently surviving patients, 16 of 39 (41%) have their bladders intact (T2, 50%; T3, 37%; T4, 0%). Only 18% of the initially enrolled population is alive with a preserved bladder. The 5-year survival of patients who had cystectomy at some point during the study, compared with those who have had their bladders preserved, was 65% versus 40%, respectively (P < 0.01). Our long-term results with multimodality therapy with attempted bladder preservation showed no definitive improvement in survival compared with modern series of cystectomy alone, and a disappointingly low rate of disease-free bladder preservation. We found a high rate of locally recurrent disease in the preserved bladders. We also noted a decrease in survival in our patients with bladder preservation compared with those without preservation. Bladder preservation, although possible, should be limited to a very select group of patients.

Background Recently we have performed a detailed analysis of early development of zebrafish swimbladder, a homologous organ of tetrapod lung; however, the events of swimbladder development are still poorly characterized. Many studies have implicated the role of vascular system in development of many organs in vertebrates. As the swimbladder is lined with an intricate network of blood capillaries, it is of interest to investigate the role of the vascular system during early development of swimbladder. Results To investigate the role of endothelial cells (ECs) and blood circulation during development of the swimbladder, phenotypes of swimbladder were analysed at three different stages (~2, 3 and 5 dpf [day postfertilization]) in cloche (clo) mutant and Tnnt2 morphants, in the background of transgenic lines Et(krt4:EGFP) sq33-2 and Et(krt4:EGFP) sqet3 which express EGFP in the swimbladder epithelium and outer mesothelium respectively. Analyses of the three tissue layers of the swimblad...

Myosin isoforms are used as markers of heterogeneity and plasticity of skeletal muscle fibers and motor units. Tedious and time-consuming methods, needing microgram or milligram amounts of myosin are widely used to characterize the heavy subunits. We here describe a sensitive method that separates in nanogram or microgram amounts the heavy chains of immature, fast and slow adult rat muscles in complex mixtures of myosins. Though the method is assembled from published procedures (SDS-PAGE, peptide mapping in the presence of SDS, silver stain) for the logical extensions introduced the end-product is a powerful tool to separate and characterize these high molecular weight biopolymers until now inseparable from complex mixtures. The method reveals the heterogeneous nature of the embryonic myosin heavy chains.