Disorganised and 'excessive' reinnervation of frog cardiac ganglia

Papers on Anthropology, 2012

The goal of this study was to determine the structure of intracardiac neurons in the frog Rana temporaria. Fifty-six intracardiac neurons from 8 animals were labelled ionophoretically by the intracellular markers AlexaFluor 586 and Lucifer Yellow CH. Among the labelled neurons, we found the cells of unipolar, bipolar, multipolar and pseudounipolar types. Multiple neuronal processes originated from the soma, the axon hillock and the initial segment of axon. With respect to the soma, the neuron contained (Mean ± SE) 3.5 ± 0.3 long and 5.5 ± 0.6 short processes. Most neurons had the spine, the bubble or the flake like extensions on their soma surface and were classified as Golgi I type neurons. Few Golgi II type neurons, the presumptive interneurons, were also found. Our findings contradict to a general view that the frog intracardiac ganglia contain only the adendritic neurons of the unipolar type. Our findings demonstrate that the frog intracardiac neurons are structurally complex and diverse. This diversity may account for the complicated integrative functions of the frog intrinsic cardiac ganglia.

Journal of Thoracic and Cardiovascular Surgery, 1996

Published descriptions of the topography of cardiac ganglia in the human heart are limited and present conflicting results. This study was carried out to determine the distribution of cardiac ganglia in adult human hearts and to address these conflicts. Hearts obtained from autopsies and heart transplant procedures were sectioned, stained, and examined. Results indicate that the largest populations of cardiac ganglia are near the sinoatrial and atrioventricular nodes. Smaller collections of ganglia exist on the superior left atrial surface, the interatrial septum, and the atrial appendage-atrial junctions. Ganglia also exist at the base of the great vessels and the base of the ventricles. The right atrial free wall, atrial appendages, trunk of the great vessels, and most of the ventricular myocardium are devoid of cardiac ganglia. These findings suggest modifications to surgical procedures involving incisions through regions concentrated with ganglia to minimize arrhythmias and related complications. Repairs of septal defects, valvular procedures, and congenital reconstructions, such as the Senning and Fontan operations, involve incisions through areas densely populated with cardiac ganglia. The current standard procedure for orthotopic heart transplantation severs cardiac ganglia and their projections to nodal and muscular tissue. One modification of the current heart transplantation procedure, involving bicaval anastomosis, preserves atrial anatomy and the cardiac ganglia. Preservation of cardiac ganglia within the donor heart may provide additional neuronal substrate for intracardiac processing and targets for regenerating nerve fibers to the donor heart. (J Thorac Cardiovasc Surg 1996;112:943-53 E fferent parasympathetic innervation of the human heart consists of preganglionic neurons located in the brain stem that project by the vagus nerve to postganglionic neurons within the cardiac ganglia. 1-3 The postganglionic neurons project to the sinoatrial (SA) and atrioventricular (AV) nodes, as well as to the atrial and ventricular musculature. 2-4 Activation of the parasympathetic pathway leads to negative chronotropic, dromotroplc, and inotropic changes in the heart. 4' 5 Afferent innervation consists of sensory neurons located in the dorsal root ganglia, nodose ganglia, and possibly the cardiac ganglia themselves. 1' 3, 6, 7 Sensory neurons influence the efferent parasympathetic pathway by the brain stem, spinal cord, and cardiac ganglia by central or local reflexes. 1' 3, 6

Anatomia, Histologia, Embryologia: Journal of Veterinary Medicine Series C, 2003

Using the thiocholine method and histological techniques, the topography and morphology of cardiac ganglia in midday gerbil, Egyptian spiny mouse, chinchilla laniger and pigeon were studied. The results demonstrated that cardiac ganglia in all investigated species are embedded in epicardial fat. They formed plexo-ganglionic structures. Each of them composed of many ganglia (from seven up to 36) different in size and shape, and interconnected by fascicles of nerve fibres. Comparative analysis showed that the density of neural network and cell aggregations was different in individual species. The richest plexo-ganglionic structure was in pigeon. It was organized in three plexo-ganglia with an average of 30 ganglia. The largest one was located along the anterior interventricular sulcus. The cardiac ganglia of investigated mammals were localized mainly on the epicardium of atria; in Egyptian spiny mouse and chinchilla laniger on the ventral surface of right atrium, but in midday gerbil on the dorsal surface of left atrium. Moreover, in midday gerbil and Egyptian spiny mouse the little plexo-ganglionic structure on the ventricle were noticed. Additionally, in midday gerbil the single nerve cells might be observed between cardiac muscle of atria. It can be said that, the strongly developed cardiac plexus in pigeon is probably connected with his behaviour and functional properties of the heart. The arrangement of neurones in cardiac ganglia of all examined mammals was uniform over the whole surface of the sections, while in the pigeon, neurones were located mainly in the peripheral part of the ganglion.

2003

The aim of the present study was to describe in detail the ultrastructure of intrinsic cardiac ganglionic cells in the healthy human as these cells appear to be directly involved in the development of tachycardia, atrioventricular block, ventricular fibrillation, and sudden cardiac death. Tissues examined in this study were obtained from hearts of 10 adult humans of either sex aged 22-80 years at autopsy performed no more than 8 h after death. The examined human intrinsic cardiac nerve cells were in most respects typical autonomic neurons surrounded by a sheath of satellite cells that was either unior multilayered. In addition to regular unmyelinated axons, prominent large axon terminals containing lamellated dense bodies, mitochondria and vesicles in the cytoplasm were observed in the ganglion neuropil. Synaptic profiles were more common in the ganglion neuropil than on neuronal somata. According to axon terminal contents, synaptic profiles were of three types. The most common Type 1 synaptic profiles contained a predominance of small clear, with a few larger dense-cored vesicles and mitochondria. Type2 synaptic profiles, in addition to the same components as in Type 1, had glycogen-like particles. Type 3 vesicle-containing profiles clearly differed from both the previous ones as they were the largest in diameter and included plentifiul large clear pleomorphic or dense-cored vesicles together with small clear and larger dense-cored vesicles, mitochondria, dense and multivesicular bodies. Independently of age of~the human, the most frequent neuronal abnormality was an abundant accumulation of inclusions inside of somata and dendrites that, in profile, appeared like circular membranous or fine granular bodies variable in electron density. In addition to inclusions, some neuronal somata and dendrites had strongly swollen mitochondria filled up with granular material in spite of their close association with normal looking ganglionic neurons. Structures resembling an axon growth cone in profile were revealed inside of cardiac ganglia derived from an 80 year old man. In conclusion, the present results provide baseline information on the normal ultrastructure of intracardiac ganglia in healthy humans which may be useful for assessing and interpreting the degree of damage of ganglionic cells both in autonomic and sensory neuropathies of the human heart.

Journal of Pediatric Advance Research, 2023

African clawed frog (Xenopus laevis) has double-inlet and single-outlet single ventricle supporting both systemic and pulmonary circulations, with normal lifespan of 25-30 years. The relationship between pulmonary and systemic blood flows was investigated using echocardiography. Twelve female African clawed frogs, age 18-24 months, mean weight 173±19 grams were studied. Heart rate, percutaneous oxygen saturation, echocardiography derived 2D and blood flow in all cardiovascular structures were measured in two temperature setting, 17 • C (normal environment for frogs) and 22 C. In eight frogs cerebral Near-Infra-Red Spectroscopy (NIRS) was measured. Mean oxygen saturation was 66±9% with temperature of 22 • C and 85±6% with 17 • C (P<0.001), while there was no statistical difference between mean heart rates, respectively 48 13 and 42±7 beats/min. Doppler echocardiography showed a mean total pulmonary blood flow (QP) =173.0 ml/min and mean total systemic blood flow (QS) = 99.3 ml/min, with mean QP/QS of 1.74:1.00. The only statistical correlation between size of the cardiovascular structures and body weight was found for the pulmonary veins, with correlation coefficient = 0.71 (P=0.02). NIRS measurements showed a reverse correlation (coefficient =-0.21) with oxygen saturation. The frog's heart has peculiar morphologic and functional characteristics allowing normal quality of life for many years despite the presence of single ventricle. Baseline QP/QS under general anesthesia was significant for increased total pulmonary blood flow. Exposure to environmental temperature 5 • C higher than normal caused peripheral vasodilatation, with subsequent decrease of QP/QS and reduced oxygenation.

Trade and Civilisation. Economic Networks and Cultural Ties, from Prehistory to the Early Modern Era, 2018

This chapter provides a theoretical framework for the formation of international trade and civilization during the Bronze Age after 3000 BC, while at the same time it situates the various contributions within this theoretical context. The focus is thus primarily on the emergence of the constituting elements of trade, as they remained in force throughout history, and accompanied the expansion of trade and civilization

Academia Materials Science, 2024

Purpose: Evaluate color change, surface roughness, and microhardness of enamel subjected to bleaching with 35% hydrogen peroxide (HP) gels combined with different concentrations of 45S5 Bioglass (BG). Methods: Enamel/dentin blocks (n=10) were submitted to: (PC) positive control with 35% HP bleaching; (HP_BG): HP combined with a gel containing BG at concentrations of 0, 2.5, 5, 7.5, 10 wt%, and a negative control (NC), with no treatment. Bleaching was performed in 3 sessions of 40 min, 7 days apart. The dental blocks were kept in artificial saliva up to 14 days after bleaching. Color parameters (ΔL, Δa, Δb), color change (ΔE00), whiteness index (ΔWId), roughness average (ΔRa), and surface microhardness were evaluated at baseline (T0), after 24h (T1), and 14 days elapsed from bleaching treatment (T2). The percentage of surface hardness loss (%SHL) was calculated at T1 and T2. Data were submitted to ANOVA and Tukey test (α=0.05). Results: No differences in ΔE00, Δb, and ΔWID among HP_BG-containing groups were observed, regardless of the BG concentration or the evaluation time points (p&gt;0.05). The NC exhibited lower ΔE00, Δb and WID than HP_BG-containing groups at both time points (T1 and T2, p&lt;0.05). Additionally, no differences were noted in ΔRa, ΔL, and Δa among the groups (p&gt;0.05). However, BG incorporation into the bleaching gels prevented enamel mineral loss in comparison to PC immediately after bleaching (T1, p&lt;0.05). At T2, 10% BG promoted lower %SHL than 0%BG, and all BG-containing groups exhibited statistically lower %SHL than PC (p&lt;0.05). The addition of BG did not affect the HP bleaching efficacy or enamel surface roughness, and the combination of BG and HP controlled enamel surface microhardness loss.

“The Turkish government did not stop there, either. After banning Mellaart, officials erected a huge fence around Çatalhöyük. And no one else dug there for the next thirty years. Unfortunately, they also left the site exposed to the elements. Before long, rain and heat destroyed several priceless murals. And mudbrick homes that had lasted nine thousand years crumbled into dust in months. All because of James Mellaart had gotten into a spat with the Turkish government”.

2008

impinan suatu perusahaan atau organisasi semakin menyadari bahwa karyawan/ petugas perlu dikembangkan dan dilatih dalam kemampuan nyata untuk dapat menyelesaikan pekerjaannya. Pelatihan setiap personil ini dirasa semakin penting manfaatnya karena tuntutan pekerjaan atau jabatan, sebagai akibat kemajuan teknologi dan semakin ketatnya persaingan diantara perusahaan yang sejenis atau organisasi. Setiap orang dituntut agar dapat bekerja efektif, efisien, kualitas, dan kuantitas pekerjaannya baik. Hal ini dilakukan untuk tujuan nonkarier maupun karir bagi para karyawan (baru atau lama) melalui latihan dan pendidikan (H. Malayu, S.P. Hasibuan, 2000). Secara alamiah orang akan berkembang bersama dengan dunia yang digelutinya, akan tetapi sering kali pertumbuhan perusahaan atau organisasi lebih cepat. Keduanya berpacu dalam arena "atletik" yang menantang. Sinkronisasi pertumbuhan organisasi dengan perkembangan orang/petugas/karyawan tidak lain adalah pengisian kesenjangan pengetahuan, keterampilan dan sikap seseorang untuk memenuhi tuntutan jabatan tertentu. Jadi pelatihan adalah proses pengisian kesenjangan pengetahuan, keterampilan dan sikap seseorang dengan tuntutan pekerjaannya. Menurut Frank, P. Sherwood & Wallace, H. Best, dalam Nunu Jumena (2000), latihan adalah proses membantu para pegawai untuk memperoleh efektivitas dalam pekerjaan mereka baik yang sekarang ataupun yang akan datang, melalui pengembangan kebiasaan-kebiasaan pikiran dan tindakan, pengetahuan, keterampilan, dan sikapnya. Menurut Moekijat (1985), ada tiga syarat yang harus dipenuhi agar suatu kegiatan dapat disebut latihan, yaitu: (1) Latihan harus membantu pegawai menambah kemampuannya. (2) Latihan harus menimbulkan perubahan dalam kebiasaan-kebiasaan bekerja dari pegawai, termasuk sikapnya terhadap pekerjaan dalam menerapkan informasi dan pengetahuan terhadap pekerjaan sehari-hari. (3) Latihan harus berhubungan dengan pekerjaan tertentu. Untuk mencapai semua ketentuan tadi maka diperlukan suatu pengelolaan atau manajemen pelatihan yang cermat mencakup perencanaannya, pengorganisasiannya, pelaksanaannya, dan pengawasan/evaluasinya.

Cuadernos de Estudios del Siglo XVIII, 2017

Pese a la importancia-e influencia-que la música ha tenido en la historia, es raro que los que la cuentan se acuerden de ella; y más de la que nos ocupa-la popular-, que ni gozó de los privilegios de la estampa-que tanta música mala nos ha legado-ni del aplauso de los poderosos, que entregaron a las «áreas» y «recigados» de los capones. De la música que se hacía en las aldeas, como la que corría por la Corte o inundaba las principales villas, apenas sabemos nada porque nadie habló de ella en su momento. Cabe pensar, no obstante, que unas y otras debieron tener su importancia porque una tradición que llega hasta hoy recuerda todavía unos cuantos temas que hunden sus raíces en el cancionero musical de la lírica popular dieciochesca, y no parecen pocos los bailes y danzas tradicionales de nuestros días que son un ejemplo de cultura degradada-gesunkenes Kulturgut-del período. I. De músicas cultas y populares Una de las constantes de la musicología europea del siglo pasado-todavía hoy de la española-ha sido su empeño por trazar una clara división entre músicas populares y cultas. Como ha puesto de manifiesto Josep Martí, pocas veces se ha tenido en cuenta que dicha dicotomía es «difusa»,-127