Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)-based scaffolds for tissue engineering

Development and selection of an ideal scaffold is of importance for tissue engineering. Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biocompatible bioresorbable copolymer that belongs to the polyhydroxyalkanoate family. Because of its good biocompatibility, PHBHHx has been widely used as a cell scaffold for tissue engineering. This review focuses on the utilization of PHBHHx-based scaffolds in tissue engineering. Advances in the preparation, modification, and application of PHBHHx scaffolds are discussed.

Progress in myofibroblast and its application in forensic medicine / 法医学杂志

The myofibroblasts have dual characteristics of smooth muscle cells and fibroblasts. In repairing tissular wound, myofibroblasts are involved in fibrogenesis and remodeling the extracellular matrix of the fibrotic cascades reaction. The review describes the morphological characteristics and biological behaviors of myofibroblasts and the application of skin wound age determination, which may provide reference for research in forensic medicine.

Identification of mechanisms involved in the relaxation of rabbit cavernous smooth muscle by a new nitric oxide donor ruthenium compound

PURPOSE: The aim of this study was to evaluate the relaxation in vitro of cavernous smooth muscle induced by a new NO donor of the complex nitrosil-ruthenium, named trans-[Ru(NH3)4(caffeine)(NO)]C13 (Rut-Caf) and sodium nitroprusside (SNP). MATERIALS AND METHODS: The tissues, immersed in isolated bath systems, were pre-contracted with phenilephrine (PE) (1 µM) and then concentration-response curves (10-12 - 10-4 M) were obtained. To clarify the mechanism of action involved, it was added to the baths ODQ (10 µM, 30 µM), oxyhemoglobin (10 µM), L-cysteine (100 µM), hydroxicobalamine (100 µM), glibenclamide, iberotoxin and apamine. Tissue samples were frozen in liquid nitrogen to measure the amount of cGMP and cAMP produced. RESULTS: The substances provoked significant relaxation of the cavernous smooth muscle. Both Rut-Caf and SNP determined dose-dependent relaxation with similar potency (pEC50) and maximum effect (Emax). The substances showed activity through activation of the soluble guanylyl cyclase (sGC), because the relaxations were inhibited by ODQ. Oxyhemoglobin significantly diminished the relaxation effect of the substances. L-cysteine failed to modify the relaxations caused by the agents. Hydroxicobalamine significantly diminished the relaxation effect of Rut-Caf. Glibenclamide significantly increased the efficacy of Rut-Caf (pEC50 4.09 x 7.09). There were no alterations of potency or maximum effect of the substances with the addition of the other ion channel blockers. Rut-Caf induced production of significant amounts of cGMP and cAMP during the relaxation process. CONCLUSIONS: In conclusion, Rut-Caf causes relaxation of smooth muscle of corpus cavernosum by means of activation of sGC with intracellular production of cGMP and cAMP; and also by release of NO in the intracellular environment. Rut-Caf releases the NO free radical and it does not act directly on the potassium ion channels.

Experimental model of human corpus cavernosum smooth muscle relaxation

PURPOSE: To describe a technique for en bloc harvesting of the corpus cavernosum, cavernous artery and urethra from transplant organ donors and contraction-relaxation experiments with corpus cavernosum smooth muscle. MATERIALS AND METHODS: The corpus cavernosum was dissected to the point of attachment with the crus penis. A 3 cm segment (corpus cavernosum and urethra) was isolated and placed in ice-cold sterile transportation buffer. Under magnification, the cavernous artery was dissected. Thus, 2 cm fragments of cavernous artery and corpus cavernosum were obtained. Strips measuring 3 x 3 x 8 mm3 were then mounted vertically in an isolated organ bath device. Contractions were measured isometrically with a Narco-Biosystems force displacement transducer (model F-60, Narco-Biosystems, Houston, TX, USA) and recorded on a 4-channel Narco-Biosystems desk model polygraph. RESULTS: Phenylephrine (1µM) was used to induce tonic contractions in the corpus cavernosum (3 - 5 g tension) and cavernous artery (0.5 - 1g tension) until reaching a plateau. After precontraction, smooth muscle relaxants were used to produce relaxation-response curves (10-12M to 10-4 M). Sodium nitroprusside was used as a relaxation control. CONCLUSION: The harvesting technique and the smooth muscle contraction-relaxation model described in this study were shown to be useful instruments in the search for new drugs for the treatment of human erectile dysfunction.

Functionomics: the analysis of a postgenomic concept on the basis of pregenomic pharmacological studies in smooth muscle

The term functionomics (Amin 2003, Neumann et al. 2004) refers to a postgenomic integrated Systems Biology (Attur et al. 2002) using a multidimensional approach for cells, tissues and organs. It considers current or future involvement among genomics, proteomics or metabolomics, including the main factors that cause biological responses and modulation under different conditions. Our objective in the present review is to summarize the contemporary understanding of functionomics of smooth muscle pharmacology, based on the results obtained on the pregenomic era during several years in our laboratory. The present approach is based on the knowledge of the dynamics of the receptor system, which comprises a cascade of phenomena, leading from the drug administration to the final biological response. We will describe several conditions in which the final effect is modified, based on perturbations induced on drug absorption, distribution, metabolism, interaction with receptors and mobilization of second messengers, as well as by interactions with a second receptor system. We will also discuss the gaps that need to be fulfilled in order to obtain a clear and better understanding of the receptor system in smooth muscle, and to narrow the bridge between ourknowledge of the function of biological systems, genomics, and other recently introduced areas.

O termo funcionômica (Amin 2003, Neumann et al. 2004) refere-se a um estudo posgenômico de Biologia de Sistemas (Attur et al. 2002), usando um enfoque multidimensional, dinâmico e simultâneo para células, tecidos e órgãos. Considera o envolvimento presente e futuro da genômica, proteômica e metabolômica incluindo os principais fatores que causam a resposta biológica final e sua modulação em diferentes condições. Nosso objetivo na presente revisão é resumir o nosso conhecimento atual em relação à funcionômica da farmacologia da musculatura lisa, baseada em resultados que obtivemos ainda na era pregenômica, durante vários anos em nosso laboratório. O presente enfoque baseia-se no que sabemos hoje em dia sobre a dinâmica do sistema receptor, que compreende uma cascata de fenômenos, que vão desde a administração de uma droga até a resposta biológica. Descreveremos várias condições nas quais a resposta é modificada, com base em perturbações produzidas na absorção, distribuição e metabolismo de fármacos, interação com receptores, mobilização de segundos mensageiros, bem como interações com um segundo sistema receptor. Discutiremos também o papel da genômica e as inúmeras falhas que devem ser preenchidas, para que se chegue a um conhecimento integrado e cada vez melhor dos sistemas receptores na musculatura lisa e para encurtar a ponte entre as funções do sistema biológico, genômica e outras áreas recentemente introduzidas.

Use of a latex biomembrane for bladder augmentation in a rabbit model: biocompatibility, clinical and histological outcomes

PURPOSE: To investigate histological features and biocompatibility of a latex biomembrane for bladder augmentation using a rabbit model. MATERIAL AND METHODS: After a partial cystectomy, a patch of a non-vulcanized latex biomembrane (2x4 cm) was sewn to the bladder with 5/0 monofilament polydioxanone sulfate in a watertight manner. Groups of 5 animals were sacrificed at 15, 45 and 90 days after surgery and the bladder was removed. The 5-µm preparations obtained from grafted area and normal bladder were stained with hematoxylin-eosin. Immunohistochemical staining was performed with a primary antibody against alpha-actin to assess muscle regeneration. RESULTS: No death, urinary leakage or graft extrusion occurred in any group. All bladders showed a spherical shape. Macroscopically, after 90 days, the latex biomembrane was not identifiable and the patch was indistinguishable from normal bladder. A bladder stone was found in one animal (6.6 percent). On the 90th day, histology revealed continuity of transitional epithelium of host bladder tissue on the patch area. At this time, the muscle layers were well organized in a similar fashion to native bladder muscle layers. The inflammatory process was higher on grafted areas when compared to controls: 15 days - p < 0.0001, 45 days - p < 0.001, and 90 days - p < 0.01. The anti alpha-actin immunoexpression peaked at 45 days, when the graft was observed covered by muscle cells. CONCLUSION: The latex biomembrane is biocompatible and can be used in models for bladder augmentation in rabbits. It promotes epithelium and muscle regeneration without urinary leakage.

Effect of KATP channel openers on myogenic and neurogenic responses in goat urinary bladder.

Isolated goat detrusor muscle exhibited spontaneous contractility with an irregular amplitude and frequency. The spontaneity of detrusor muscle exhibited a mean amplitude as 11.99 +/- 0.83 mm and frequency as 1.37 +/- 0.16/min. KATP-channel openers namely, cromakalim or pinacidil (10(-7) - 10(-4) M) added cumulatively, elicited a concentration-related inhibition of both amplitude and rate of spontaneous contractions. The mean IC50 values for both amplitude and frequency for cromakalim were 3.3 x 10(-6) M and 2.9 x 10(-6) M, respectively; and for pinacidil were 2.0 x 10(-5) M and 1.5 x 10(-5) M, respectively. Glibenclamide, a KATP-channel blocker inhibited the cromakalim-induced concentration-related relaxation of spontaneous contractions with a significant increase in its mean IC50. ACh-induced concentration-related contractile response was inhibited in the presence of either cromakalim (10(-4) M) or pinacidil (10(-4) M). The mean EC50 value of ACh, in the presence of cromakalim (2.5 x 10(-3) M) was significantly increased as compared to the control (1.2 x 10(-6) M). In the presence of glibenclamide (10(-5) M) the inhibitory effect of cromakalim was significantly reduced with consequent decrease in the EC50 value (1.9 x 10(-5) M). Application of EFS (30 V and 5 ms) on goat urinary bladder strips at 1, 2, 5, 10, 20 and 30 Hz elicited frequency-related contractile responses. Both cromakalim and pinacidil caused a rightward shift in the frequency-related contractile response curve with significant increase in the mean EF25 and EF50 values, respectively. In the presence of glibenclamide (10(-4) M), the frequency-related inhibitory response curve was shifted to left with significant (P < 0.001) increase in the mean EF25, EF50 and EF75. The present results suggest that in the goat detrusor muscle, agonist and EFS-induced contractile responses were more potently inhibited by cromakalim than pinacidil with activation of glibenclamide sensitive KATP channels.

Disipación energética y protección vascular durante la hipertensión arterial sistémica: rol del músculo liso / Energetic dissipation and vascular protection during the systemic arterial hypertension: rol of the smooth muscle

Introducción: las arterias amortiguan las oscilaciones de alta frecuencia de las ondas de presión y flujo disipando energía. El amortiguamiento protege la pared arterial de daños relacionados con dichas oscilaciones. Objetivo: analizar el rol del músculo liso vascular (MLV) en la protección parietal y disipación energética de arterias carótidas (ACC) de sujetos normotensos, hipertensos e hipertensos tratados con inhibidores de la enzima conversora de angiotensina (ECA). Métodos: presión (tonometría) y diámetro (ecografía) carotídeos se registraron en sujetos normotensos (n=12) e hipertensos (n=22) asignados aleatoriamente al tratamiento placebo (n=10) o inhibidores de ECA (ramipril 5-10 mg/día n=12). Se midió in vitro, presión, diámetro en ACC de donantes (n=4; tono vascular nulo), en condiciones hemodinámicas similares a las de los sujetos. Se calculó para cada latido, usando modelización adaptativa, el índice viscoso, elástico e inercial, la energía disipada (Wn) fue mayor (p<0,05) que en los normotensos, mientras que la protección parietal fue similar. Solo en los hipertensos tratados, la Wn se acercó a los valores de los normotensos, sin cambiar la protección parietal. En situación de tono nulo (in vitro) la Wn y la protección parietal fueron menores que en los normotensos (p<0,01), evidenciando la dependencia de estos parámetros con el tono muscular. Conclusión: el sistema arterial mantiene la protección parietal. El MLV protege la pared disipando energía. En hipertensos, la disipación energética aumenta, y se mantiene amortiguamiento y la protección parietal. La disipación energética puede reducirse (tratamiento), disminuyendo la poscarga ventricular y manteniendo la protección arterial.

Effects of ligustrazine on the contraction of isolated rabbit corpus cavernosum strips / 华中科技大学学报（医学）（英德文版）

To investigate the role of ligustrazine on relaxation of the isolated rabbit corpus cavernosum tissue in vitro, the effects of ligustrazine on the corpus cavernosum were observed by using experimental method of smooth muscle strips. Concentration-responses to phenylephine (PE) and KCl were recorded. The results showed that ligustrazine concentration-dependently depressed the contraction response of smooth muscle strips induced by PE. The maximum percentage relaxation of cavernosal strips by ligustrazine was 74.1% +/- 6.2% (compared with control: 21.9% +/- 5.6%, P < 0.01). Ligustrazine concentration-dependently reduced the amplitude of the contraction induced by cumulative doses of PE or KCl, shifted the cumulative concentration response curves of PE and KCI to the right and depressed their maximal responses. It was concluded that ligustrazine could significantly relax the cavernosal muscle contraction induced by PE in vitro. The results suggested that ligustrazine inhibited calcium ion influx.

Uterine mast cells: a new hypothesis to understand how we are born

Birth is the result of complex, well-defined, and coordinated events, that are tightly regulated by endocrine, nervous, and immune responses, and take place primarily in the female reproductive tract. Various mechanisms and mediators involved in pregnancy, labor, and delivery, are highly conserved among different mammalian species and mast cells emerge as potential and crucial participants in these processes, as it is discussed in this review.

Ca2+ entry, efflux and release in smooth muscle

Control of smooth muscle is vital for health. The major route to contraction is a rise in intracellular [Ca2+], determined by the entry and efflux of Ca2+ and release and re-uptake into the sarcoplasmic reticulum (SR). We review these processes in myometrium, to better understand excitation-contraction coupling and develop strategies for preventing problematic labours. The main mechanism of elevating [Ca2+] is voltage-gated L-type channels, due to pacemaker activity, which can be modulated by agonists. The rise of [Ca2+] produces Ca-calmodulin and activates MLCK. This phosphorylates myosin and force results. Without Ca2+ entry uterine contraction fails. The Na/Ca exchanger (NCX) and plasma membrane Ca-ATPase (PMCA) remove Ca2+, with contributions of 30 percet and 70 percet respectively. Studies with PMCA-4 knockout mice show that it contributes to reducing [Ca2+] and relaxation. The SR contributes to relaxation by vectorially releasing Ca2+ to the efflux pathways, and thereby increasing their rates. Agonists binding produces IP3 which can release Ca from the SR but inhibition of SR Ca2+ release increases contractions and Ca2+ transients. It is suggested that SR Ca2+ targets K+ channels on the surface membrane and thereby feedback to inhibit excitability and contraction.

Effect of low temperature on tracheal smooth muscle contractile and relaxing responses evoked by electrical field stimulation

OBJECTIVE: The aim of this work was to evaluate the effect of low temperature (LT) on the contractile and relaxing responses of rat tracheas (RTs) after electrical field stimulation (EFS). METHODS: Voltage-dependent (10-60 V, 40 Hz) and frequency-dependent (0.1-60 Hz, 40 V) response curves were constructed at 37 and 18 degrees C after the activation of tracheal intramural nerves with a Grass S88 stimulator. The EFS that produced half of the maximum contractile response (ES50) at 37 or 18 degrees C was determined and considered as the dependent variable. The relaxation of pre-contracted RTs (EFS; 5 Hz, 40 V) to sodium nitroprusside (SNP; 1 x 10(-7) - 1 x 10(-3) M) isoproterenol (ISP; 1 x 10(-9) - 1 x 10(-5) M) and to 20 mM potassium chloride (KCl) after low-K+ inhibition of the Na+/K+ pump at 18 and 37 degrees C were determined. RESULTS: We found that the tracheal responses elicited by EFS at 37 and 18 degrees C were completely blocked with 1 microM atropine. LT slightly increases the voltage-dependent ES50, from 33.7 +/- 4.0 to 37.8 +/- 4.8 V, n = 5 but decreases the frequency-dependent ES50 from 19.3 +/- 4.3 to 1.0 +/- 0.28 Hz, n = 5, p < 0.05. Relaxing responses to SNP, ISP and KCl at 37 degrees C correspond to 43.5 +/- 6, 36.7 +/- 12 and 12.1 +/- 1.5 respectively. No significant tracheal relaxations were elicited at 18 degrees C. Our results indicate that in RTs, LT enhances tracheal sensitivity to EFS and decreases it in response to bronchorelaxants. The LT-dependent enhanced contractile response is observed only after a low frequency stimulation range (0.1-20 Hz), that is very close to the frequency of vagal stimuli required for inducing bronchoconstriction in vivo. Furthermore, LT abolishes the sensitivity of RTs to exogenously added bronchorelaxants (NO and ISP). In addition, LT appears to decrease the Na(+)-K+ pump activity; this effect has been associated with increased tracheal hyperreactivity in vitro. ACH appears to be the main endogenous neurotransmitter involved on neurally mediated contractile responses at 37 and 18 degrees C. CONCLUSION: Low temperature enhances the contractile response of rat tracheas in response to endogenous ACH release. The effect of LT is limited to frequencies below 20 Hz, which are within the physiological range required for bronchoconstriction. Furthermore, LT severely impairs the sensitivity of RTs to relaxant stimuli, either of endogenous of exogenous origin.

Effects of acetaldehyde on responses of rabbit corpus cavernosal smooth muscle

Ethanol has various effects on male sexual activity under the influence of direct and indirect, in acute and chronic alcohol ingestion. However, whether acetaldehyde, a principal metabolite of ethanol, may affect penile erection directly has still not been elucidated. This present study was, therefore, designed to clarify the pharmacologic effects of the acetaldehyde on corpus cavernosal smooth muscle. Corpus cavernosal strips were prepared from rabbit penises. Isometric tension changes of rabbit corpus cavernosal strips to various drugs and electrical field stimulation (EFS) in an organ chamber were recorded with a pressure transducer after active muscle tone had been induced by phenylephrine (10(-5) mol/L). At the concentrations employed, acetaldehyde had no effect on the pH of the bathing medium. Acetaldehyde in each concentration did not significantly affect resting tone of the smooth muscle during 30 min incubation. Acetaldehyde suppressed contractility induced by phenylephrine and KCI at 10(-4) mol/L, and relaxation induced by EFS and bethanechol at 10(-3) mol/L and 10(-4) mol/L respectively, but acetaldehyde enhanced relaxation induced by ATP at high acetaldehyde level. Sodium nitroprusside-induced relaxation was not affected at any employed acetaldehyde concentration. This suggests that increasing the acetaldehyde level may contribute to male erectile dysfunction mainly by the inhibition of nitric oxide formation.

Effects of acetaldehyde on responses of rabbit corpus cavernosal smooth muscle

Ethanol has various effects on male sexual activity under the influence of direct and indirect, in acute and chronic alcohol ingestion. However, whether acetaldehyde, a principal metabolite of ethanol, may affect penile erection directly has still not been elucidated. This present study was, therefore, designed to clarify the pharmacologic effects of the acetaldehyde on corpus cavernosal smooth muscle. Corpus cavernosal strips were prepared from rabbit penises. Isometric tension changes of rabbit corpus cavernosal strips to various drugs and electrical field stimulation (EFS) in an organ chamber were recorded with a pressure transducer after active muscle tone had been induced by phenylephrine (10(-5) mol/L). At the concentrations employed, acetaldehyde had no effect on the pH of the bathing medium. Acetaldehyde in each concentration did not significantly affect resting tone of the smooth muscle during 30 min incubation. Acetaldehyde suppressed contractility induced by phenylephrine and KCI at 10(-4) mol/L, and relaxation induced by EFS and bethanechol at 10(-3) mol/L and 10(-4) mol/L respectively, but acetaldehyde enhanced relaxation induced by ATP at high acetaldehyde level. Sodium nitroprusside-induced relaxation was not affected at any employed acetaldehyde concentration. This suggests that increasing the acetaldehyde level may contribute to male erectile dysfunction mainly by the inhibition of nitric oxide formation.

La reactividad de la musculatura bronquial en sujetos jóvenes: patrones en condiciones normales / Bronchial muscle reactivity in young healthy individuals: the pattern in normal conditions

Se analizan críticamente el método presentado en un trabajo anterior en el que se explora, de una manera sencilla, en el hombre, la reactividad de la musculatura de los broquios. Se presentan los resultados obtenidos con este método en 35 sujetos jóvenes sanos. El propósito fue el de encontrar valores que pudieron ser considerados como representativos de los patrones normales para individuos sanos, los cuales podrían servir de base para su comparación con los que se obtengan en los estudios de caso patológicos. Se discute la posibilidad de que la medida de la circunferencia torácica no presente un cambio proporcional de la capacidad pulmonar. Se presentan los resultados de los controles realizados en apoyo de este postulado, uno de los que sirvieron de base para la justificación del método. Se confirma que el músculo liso de los bronquios se encuentra en estado dinámico en las condiciones fisiológicas y que participa en la actividad refleja del sistema nervioso autónomo y en los estados emocionales. Se compara la actividad de este tipo de músculo con la de otros efectos autonómicos

Comparison of relaxation responses of cavernous and trigonal smooth muscles from rabbits by alpha1-adrenoceptor antagonists; prazosin, terazosin, doxazosin, and tamsulosin

Alpha1a-adrenergic receptor (AR) primarily mediates the contraction of the prostatic and cavernous smooth muscles. Among clinically available alpha1-AR antagonists for the medical management of benign prostatic hyperplasia (BPH), tamsulosin has a modest selectivity for alpha1A- and alpha1D- over alpha1B-ARs. To compare the effects of various alpha1-AR antagonists on relaxation responses of cavernous and trigonal smooth muscles, isometric tension studies with relatively selective (tamsulosin) and non-selective (prazosin, doxazosin, and terazosin) alpha1A-AR antagonists, were conducted in the cavernous and trigonal muscle strips of rabbits (n=10 each). Tamsulosin had the strongest inhibitory effect on contraction of trigonal smooth muscle among the various alpha1-AR antagonists, and the inhibitory activities of prazosin, doxazosin, and terazosin were not statistically different. All alpha1-AR antagonists caused concentration-dependent relaxation of the cavernous muscle strips. Tamsulosin was shown to have greater potency than prazosin (more than 100-fold), doxazosin (more than 1000-fold), and terazosin (more than 1000-fold), in relaxation of cavernous smooth muscle. In conclusion, tamsulosin might be the most effective drug among the four commonly used alpha1-AR antagonists for the medical management of BPH. Tamsulosin might be a potential substitute for phentolamine in combination with vasoactive agents as an intracavernous injection therapy for patients with erectile dysfunction.

Different roles of histamine receptor subtypes in ampullar & isthmic segments of human fallopian tube.

We have studied the influence of both menstrual cycle phase and subtype-selective histamine antagonists on the contractions produced by histamine isolated in human fallopian tubes. Histamine produced tonic contractions of the isolated preparations of both the ampullar and isthmic segments of the human fallopian tube were analyzed. The effects of both histamine and its antagonists were not dependent on the phase of the menstrual cycle. The isolated preparations of the ampullar segment from post menopausal patients were not responsive on histamine. When responding, the ampullar segments were slightly more sensitive to histamine than the isthmic segments. All three subtype selective histamine antagonists (pyrilamine, cimetidine and thioperamide) produced strong inhibition of histamine evoked contractions of the ampullar segment. On the other hand, only pyrilamine strongly inhibited histamine evoked contractions of the isthmic segment. The results of our study suggest that only H1 receptors were responsible for the histamine contractile effect on the isthmic segment and that all three subtypes of histamine receptors were involved in the effect of histamine on the ampullar segment of human fallopian tube.

Manometric mapping of normal esophagus and definition of the transition zone.

BACKGROUND: The normal esophagus has not been manometrically mapped. The transition zone between esophageal smooth and skeletal muscles has also not been defined manometrically. AIMS: To manometrically map the normal esophagus and to define the transition zone. METHODS: Thirty normal adults [23 men; mean age 34.8 (10.4) years] underwent manometry using a water-perfused system. The lower esophageal sphincter (LES) was studied by station pull-through, and esophageal body musculature was evaluated at 1-cm intervals with five wet swallows at each level. The transition zone was identified as an area where the wave-forms did not resemble typical skeletal or smooth muscle wave-forms. RESULTS: The basal mid-expiratory LES pressure was 18.7 (7.2) mmHg, and its length was 3.6 (1.2) cm. Based on our findings, we defined the transition zone as an area where either the amplitude of contraction was < 40 mmHg or, if the amplitude was 40-50 mmHg, the rate of change of pressure from baseline to peak of the wave was < 50 mmHg/s. The lengths of the skeletal, transition and smooth muscle zones were 2.8 (1.2), 4.0 (1.7) and 12.5 (2.7) cm, respectively. The amplitude and dp/dt of contraction and transmission velocity were lowest in the transition zone (p < 0.05). CONCLUSIONS: We have manometrically mapped the normal esophageal muscle zones; the parameters obtained may be used as reference values. The manometric criteria for the transition zone have also been defined.

Controle neuroendócrino da contraçäo uterina / The neuroendocrine control of uterine contraction

Os autores apresentam uma revisäo acerca da contratilidade da musculatura lisa uterina. Foram abordados os aspectos relacionados ao controle neural, hormonal e à atuaçäo de outras substâncias envolvidas no mecanismo de contraçäo da mesma. Dentre estas substâncias foi descrita a atuaçäo do Misoprostol, um análogo de prostaglandina sintetizado laboratorialmente, que exerce potente atividade contrátil sobre a rferida musculatura

Sphingomyelin metabolites as second messengers in airway smooth muscle cell proliferation

Sphingolipid metabolism was examined in guinea-pig airway smooth muscle cells stimulated by platelet-derived growth factor [PDGF] and 4[BETA]-phorbol 12-myristate 13-acetate [PMA], as mitogens and bradykinin [BK] as non-mitogen. Stimulation of the cells by PMA and PDGF for 60 min. at 37°C induced the following changes in sphingolipid metabolites: in cells prelabeled with [3] H palmitate, a 1.2 fold increase in radio-labeled sphingosine, a concomitant 20% decrease in radio-labeled ceramide and no significant change in sphingomyelin level. Stimulation of the cells by BK induced no changes in sphingolipid levels at any time tested. This study demonstrates the existence of a "sphingomyelin cycle" in airway smooth muscle cells. Such sphingolipid cycles may function in a signal transduction pathway and in cellular proliferation