A simple laboratory exercise with rat isolated esophagus and stomach fundus to reveal functional differences between striated and smooth muscle cells

Novel Anthranilic Acid Hybrids-An Alternative Weapon against Inflammatory Diseases

Anti-inflammatory drugs are used to relieve pain, fever, and inflammation while protecting the cardiovascular system. However, the side effects of currently available medications have limited their usage. Due to these adverse effects, there is a significant need for new drugs. The current trend of research has shifted towards the synthesis of novel anthranilic acid hybrids as anti-inflammatory agents. Phenyl- or benzyl-substituted hybrids exerted very good anti-inflammatory effects in preventing albumin denaturation. To confirm their anti-inflammatory effects, additional ex vivo tests were conducted. These immunohistochemical studies explicated the same compounds with better anti-inflammatory potential. To determine the binding affinity and interaction mode, as well as to explain the anti-inflammatory activities, the molecular docking simulation of the compounds was investigated against human serum albumin. The biological evaluation of the compounds was completed, assessing their antimicrobial activity and spasmolytic effect. Based on the experimental data, we can conclude that a collection of novel hybrids was successfully synthesized, and they can be considered anti-inflammatory drug candidates-alternatives to current therapeutics.

On a coupled electro-chemomechanical model of gastric smooth muscle contraction

The stomach is a central organ in the gastrointestinal tract that performs a variety of functions, in which the spatio-temporal organisation of active smooth muscle contraction in the stomach wall (SW) is highly regulated. In the present study, a three-dimensional model of the gastric smooth muscle contraction is presented, including the mechanical contribution of the mucosal and muscular layer of the SW. Layer-specific and direction-dependent model parameters for the active and passive stress-stretch characteristics of the SW were determined experimentally using porcine smooth muscle strips. The electrical activation of the smooth muscle cells (SMC) due to the pacemaker activity of the interstitial cells of Cajal (ICC) is modelled by using FitzHugh-Nagumo-type equations, which simulate the typical ICC and SMC slow wave behaviour. The calcium dynamic in the SMC depends on the SMC membrane potential via a gaussian function, while the chemo-mechanical coupling in the SMC is modelled via an extended Hai-Murphy model. This cascade is coupled with an additional mechano-electrical feedback-mechanism, taking into account the mechanical response of the ICC and SMC due to stretch of the SW. In this way the relaxation responses of the fundus to accommodate incoming food, as well as the typical peristaltic contraction waves in the antrum for mixing and transport of the chyme, have been well replicated in simulations performed at the whole organ level. STATEMENT OF SIGNIFICANCE: In this article, a novel three-dimensional electro-chemomechanical model of the gastric smooth muscle contraction is presented. The propagating waves of electrical membrane potential in the network ofinterstitial cells of Cajal (ICC) and smooth muscle cells (SMC) lead to a global pattern of change in the calciumdynamics inside the SMC. Taking additionally into account the mechanical response of the ICC and SMC due to stretch of the stomach wall, also referred to as mechanical feedback-mechanism, the result is a complex spatio-temporal regulation of the active contraction and relaxation of the gastric smooth muscle tissue. Being a firstapproach, in future view such a three-dimensional model can give an insight into the complexload transferring system of the stomach wall, as well as into the electro-chemomechanicalcoupling process underlying smooth muscle contraction in health and disease.

Precise Three-Dimensional Morphology of the Male Anterior Anorectum Reconstructed From Large Serial Histologic Sections: A Cadaveric Study

BACKGROUND

Deep anatomic knowledge of the male anterior anorectum is important to avoid urethral injury and rectal perforation in intersphincteric resection or abdominoperineal resection for very low rectal cancer. However, its structure is difficult to understand, because the anorectum, muscles, and urogenital organs are complicatedly and 3-dimensionally arranged.

OBJECTIVE

The purpose of this study was to revisit the anatomic information of the male anterior anorectum for intersphincteric resection and abdominoperineal resection with a focus on the spatial muscular morphology.

DESIGN

This was a descriptive cadaveric study.

SETTINGS

The study was conducted at Ehime and Kyoto universities.

PATIENTS

Tissue specimens from 9 male cadavers were included.

MAIN OUTCOME MEASURES

Specimens around the anterior anorectum were serially sectioned in the horizontal, sagittal, or frontal plane; large semiserial histologic sections were created at 250-μm intervals. The series were stained with Elastica van Gieson, and some sections from the series were studied by immunohistochemistry to detect smooth and striated muscles. Two series were digitalized and reconstructed 3-dimensionally.

RESULTS

Two regions without a clear anatomic border were elucidated: 1) the anterior region of the external anal sphincter, where the external anal sphincter, bulbospongiosus muscle, and superficial transverse perineal muscle were intertwined; and 2) the rectourethralis muscle, where the smooth muscle of the longitudinal muscle continuously extended to the posteroinferior area of the urethra, which became closest to the anorectum at the prostatic apex level. A tight connection between the striated and smooth muscles was identified at the anterior part of the upper external anal sphincter and anterolateral part of the puborectalis muscle level.

LIMITATIONS

This study involved a small sample size of elderly cadavers.

CONCLUSIONS

This study clarified the precise spatial relationship between smooth and striated muscles. The detailed anatomic findings will contribute more accurate step-by-step anterior dissection in intersphincteric resection and abdominoperineal resection, especially with the transanal approach, which can magnify the muscle fiber direction and contraction of striated muscle by electrostimulation. MORFOLOGÍA TRIDIMENSIONAL PRECISA DEL ANORRECTO ANTERIOR MASCULINO RECONSTRUIDO A TRAVÉS DE SECCIONES MAYORES HISTOLÓGICAS EN SERIE: UN ESTUDIO CADAVÉRICO: El conocimiento anatómico amplio del anorrecto anterior masculino es importante para evitar lesiones de uretra y perforación de recto en la resección interesfinterica o la resección abdominoperineal para cáncer de recto bajo. Sin embargo, su estructura es difícil de entender porque el anorrecto, los músculos y los órganos urogenitales están aliñados en forma complexa tridimensional.

OBJETIVO

Revisar de nuevo el conocimiento anatómico del anorrecto anterior masculino relevante a la resección interesfinterica y la resección abdominoperineal con un enfoque en la morfología muscular espacial. DISEÑO:: Estudio descriptivo cadavérico.

ENTORNO

Ehime y la Universidad de Kyoto.

SUJETOS

Tejido especímenes de nueve cadáveres masculinos. PUNTOS FINALES DE VALORACIÓN:: Las muestras alrededor del anorrecto anterior se seccionaron en serie en planos horizontal, sagital y coronal. Se crearon mayores secciones histológicas en serie a intervalos de 250 μm. Los especímenes fueron teñidos con Elástica van Gieson, y algunas secciones de la serie se estudiaron mediante inmunohistoquímica para detectar músculos lisos y estriados. Dos series fueron digitalizadas y reconstruidas tridimensionalmente.

RESULTADOS

Se demostraron dos regiones sin un borde anatómico definido: (i) la región anterior del esfínter anal externo, donde se entrelazaron el esfínter anal externo, el músculo bulbospongoso y el músculo perineal transverso superficial; y (ii) músculo rectouretral, donde el músculo liso del músculo longitudinal se extiende continuamente a la zona posteroinferior de la uretra, que se acerca más al anorrecto a nivel del ápice prostático. La conexión estrecha entre los músculos estriados y lisos se identificó en la parte anterior del esfínter anal externo superior y la parte anterolateral del nivel del músculo puborrectal. LIMITACIÓN:: Este estudio incluyó una muestra pequeña de cadáveres ancianos. CONCLUSIÓN:: Este estudio aclaró la relación espacial precisa entre los músculos lisos y estriados. Los hallazgos anatómicos detallados ayudarán para una disección anterior paso a paso más precisa en la resección interesfintérica y la resección abdominoperineal, especialmente con el abordaje transanal, que puede magnificar la dirección de las fibras musculares y la contracción del músculo estriado utilizando electroestimulación.

Pedagogical training profile of basic health sciences faculty in biomedical and related fields at Brazilian public and private higher education institutions

Historically, Brazilian higher education teachers' pedagogical training has not been a concern. Even today, a graduate degree is the main requirement to be a faculty member. However, a set of competencies is necessary to teach: pedagogical competency, political competency, and knowledge of specific content. Most graduate training covers only knowledge of specific content. Therefore, this work aimed to outline the profile of basic health sciences faculty members teaching in biomedical and related fields regarding their undergraduate and graduate training, as well as the initial and continued pedagogical training in Brazilian public and private higher education institutions (HEIs). An electronic questionnaire was sent to these professionals, and a total of 763 responses were analyzed (66.4% from public and 33.6% from private HEIs). Compared with private HEI faculty, faculty from public HEIs were more experienced in teaching, and more time had passed since they finished their graduate training. On the other hand, faculty from private HEIs had a more intense undergraduate teaching workload than faculty from public HEIs. Additionally, faculty from private HEIs attended more extensive and more frequent pedagogical training activities (PTAs). Both groups expressed that activities closely related to their classroom practice and recognition for good pedagogical performance were incentives for their participation in PTAs. In conclusion, differences between the faculty from public and private HEIs may be due to the characteristics of HEIs themselves. Hypothetically, private HEIs focus on teaching, which may explain why faculty from these institutions seek improvement in this area, whereas public HEIs focus on research.

Impairment of rat oesophageal muscle contractility associated with experimental non-erosive oesophageal mucosal damage

NEW FINDINGS

What is the central question of this study? Is the responsiveness of isolated segments of the rat oesophagus to contractile or relaxant stimuli susceptible to acute luminal exposure of the oesophagus to an acid solution that contains pepsin and bile salt? What is the main finding and its importance? The study reveals that luminal acidity is an important factor that disrupts barrier function in the oesophagus to allow the diffusion of noxious agents, such as bile acid, that alter the contractile status of the oesophageal body, even in the absence of inflammation.

ABSTRACT

We investigated whether the experimental simulation of duodenogastro-oesophageal reflux alters the contractile responsiveness of rat oesophageal strips. After 30 min of luminal exposure to a solution at acid pH that contained pepsin and taurodeoxycholic acid, isolated strips of the rat oesophagus and gastro-oesophageal junction were subjected to contractile or relaxing stimuli. Acid challenge decreased the responsiveness of oesophageal strips to contractile stimulation, especially in oesophageal preparations that were mounted following the circular orientation of the muscularis externa layer. The contractility of longitudinal preparations of the rat oesophagus appeared less susceptible to the deleterious effects of acid challenge. In contrast, the responsiveness of ring-like preparations from the gastro-oesophageal junction to contractile stimulation was unaltered by acid challenge. Taurodeoxycholic acid decreased the responsiveness of circular oesophageal preparations to KCl, an effect that was exacerbated by luminal acidity. On the contrary, although the relaxant ability of the rat oesophagus did not change, acid challenge increased the relaxant efficacy of sodium nitroprusside and isoprenaline in strips of the gastro-oesophageal junction. A significant decrease in transepithelial electrical resistance was seen when the oesophageal mucosa was challenged at pH 1 but not at pH 4. Treatment with alginate blunted the deleterious effects of acid challenge on transepithelial electrical resistance and the responsiveness of oesophageal preparations to KCl. The present findings support the notion that luminal acidity is an important factor that disrupts barrier function in the oesophagus to allow the diffusion of noxious agents, such as bile acid, that alter the contractile status of the oesophagus.

Status of research on physiology education in Brazil

Physiology education research aims to investigate teaching-learning aspects and methods specifically applied to physiology teaching and learning. In this paper exploring Brazilian research public data and information from the Brazilian Physiological Society Teaching Committee, we investigated the status of this research topic (physiology education) in Brazil. The data showed that physiology education research needs to be more recognized and supported in Brazil, and more physiologists may become interested in research in this field. Thus this field will become more developed during the physiologists' education.