Vasculature of the head and respiratory organs in an obligate air-breathing fish,the swamp eel Monopterus (=Amphipnous) cuchia

Methyl methacrylate vascular corrosion replicas were used to examine the macrocirculation in the head region and the microcirculation of respiratory vessels in the air-breathing swamp eel Monopterus cuchia. Fixed respiratory tissue was also examined by SEM to verify capillary orientation. The respiratory and systemic circulations are only partially separated, presumably resulting in supply of mixed oxygenated and venous blood to the tissues. A long ventral aorta gives rise directly to the coronary and hypobranchial arteries. Two large shunt vessels connect the ventral aorta to the dorsal aorta, whereas the remaining ventral aortic flow goes to the respiratory islets and gills. Only two pairs of vestigial gill arches remain, equivalent to the second and third arches, yet five pairs of aortic arches were identified. Most aortic arches supply the respiratory islets. Respiratory islet capillaries are tightly coiled spirals with only a fraction of their total length in contact with the respiratory epithelium. Valve-like endothelial cells delimit the capillary spirals and are unlike endothelial cells in other vertebrates. The gills are highly modified in that the lamellae are reduced to a single-channel capillary with a characteristic three-dimensional zig-zag pathway. There are no arterio-arterial lamellar shunts, although the afferent branchial artery supplying the gill arches also supplies respiratory islets distally. A modified interlamellar filamental vasculature is present in gill tissue but absent or greatly reduced in the respiratory islets. The macro- and micro-circulatory systems of M. cuchia have been considerably modified presumably to accommodate aerial respiration. Some of these modifications involve retention of primitive vessel types, whereas others, especially in the microcirculation, incorporate new architectural designs some of whose functions are not readily apparent.     

Haemodynamic effects of adenosine on gills of the trout (Salmo gairdneri)

Summary The haemodynamic effects of adenosine on gills of the trout (Salmo gairdneri) were studied with in vitro and in vivo preparations.On the isolated head preparation, adenosine induced a decrease of the ventral aortic inflow and of the dorsal aortic outflow. Simultaneously the venous outflow increased. These effects were antagonized by theophylline. Adenosine induced a vasoconstriction in gill arches without filaments perfused by the afferent or the efferent branchial arteries. The efferent vessels were more sensitive to adenosine than afferent vessels. The whole systemic circulation of the isolated trunk did not show any response to adenosine. When adenosine was infused into the ventral aorta of living trout, the gill resistance to blood flow was greatly increased.These results suggest that adenosine is able to control the arterious and venous blood pathways in the trout gills by modulating their vascular resistance.     

An angiographic study of the carotid arterial and jugular venous systems in the cat.

Standard techniques for performing carotid angiography in dogs and in man were adapted to the cat in order to study the vascularization of both intracranial and extracranial structures. Venous drainage was examined by venography of selected vessels. The carotid-cerebral and the vertebral-basilar arterial systems of the cat were studied, although no attempt was made to define the territory supplied by each system. In serial angiograms, vascularization of the rete mirabile conjugatum was visualized and distinct arterial and venous retia were delineated. Large facial veins were seen approximately one second after the intra-arterial injection of radio-contrast material. The early filling of the large facial veins appeared to be the result of an artery-to-venous shunt. Contrast material flowed posteriorly in these veins and drained into the venous rete. When contrast material was injected either into the sagittal sinus or retrograde in the external jugular vein, the internal jugular vein was visible in four of ten cats. This vessel drained blood directly from intracranial contents before anastomosis with the vertebral and external jugular veins.     

Microscopic studies on the transition between the sigmoid sinus, the superior bulb of the jugular vein and the first portion of the internal jugular vein

The author studied the structure of the tissue components of the tunicae of the terminal segment of the sigmoid sinus, particularly at the level of the transition between the sigmoid sinus, the superior bulb of the jugular vein and the first portion of the human internal jugular vein; it was established that the transition between the sigmoid sinus and the first portion of the internal jugular vein occupies the whole extension of the superior bulb of the jugular vein up to the inferior third of the first portion of this vessel. These vascular walls exhibit a structure similar to that of the dura, i.e. the tunica adventitia is formed by fascicles of collagenic fibers which describe discontinuous spirals, more open proximal to the beginning of the first portion of the internal jugular vein. Approximately in the inferior third of the first portion of the internal jugular vein, there appear fascicles of smooth muscle fibers which are arranged similarly to those of the venous walls. The tunica intima of these vascular segments exhibits an endothelium resting on a network of elastic fibers which may play the role of an internal elastic lamina. From the bony border of the jugular foramen there originates a connective system whose fascicles of collagenic and elastic fibers incorporate to the wall of the internal jugular vein after describing a stretch in spiral around the vascular lumen.     

Angiology of the brain of the baboon Papio ursinus, the vervet monkey Cercopithecus pygerithrus, and the bushbaby Galago senegalensis

The investigation was undertaken to compare the blood supply and venous drainage of the brain of the baboon P. ursinus, the vervet monkey C. pygerithrus, and the bushbaby G. senegalensis with that of man, because these animals are extensively used as research models. The blood supply of the three primates was found to be similar in each case. Like man they have a complete circulus arteriosus; but they have a single anterior cerebral artery, whereas man has paired anterior cerebral arteries. The arterial supply to the cerebellum in the primates is similar to that in man, the main difference being a "common inferior cerebellar artery" which bifurcates to form the anterior inferior cerebellar and posterior inferior cerebellar arteries. In man, these arteries arise separately from the basilar artery and vertebral arteries, respectively. The dural venous drainage was also found to be similar in these primates but was far more extensive than in man. The primates have additional sinuses--the more important of these being the "basisphenoid sinus" and the petrosquamous sinus. The former drains the basilar sinus and is itself drained via the vertebral venous plexus and internal jugular vein. The latter drains via the petrosquamous foramen into the retromandibular vein. The petrosquamous sinus has a rostral extension which drains through the foramen ovale and two lateral and medial connecting sinuses which drain the cavernous and basilar sinuses, respectively. These sinuses are not found in man.     

Study on vascular system in the gills of some teleosts by the resin-replica method

Arterio-arterio and arterio-venous vasculatures in the gills of eelAnguilla japonica, carpCyprinus carpio, and yellowtailSeriola quinqueradiata were examined by resin-replica method. Their ampullae and anastomotic capillaries of secondary lamellae exhibited species differences in the structural features. In the infusion of resin into the eel gills for 2, 5, and 10 min, the replica of afferent companion vessels, central venous sinus, efferent companion vessel, and afferent artery was produced, but that of the capillaries in secondary lamellae and efferent artery was not recognizable. This finding suggests more abundant blood circulation in the arteriovenous vasculature than in the arterio-arterio one.     

Functional Organization of the Teleost Gill

The circulation of the gills has been studied in the perch, trout and eel combining the conventional histological methods and casting techniques. The existence of two blood pathways in each gill arch was confirmed. 1 — An arterio-arterial pathway assuming the respiratory function. It includes the afferent branchial artery and in each primary lamella the afferent primary artery, the secondary lamellae capillaries and the primary and branchial efferent arteries. 2 — An arterio-venous pathway arising from both the branchial artery, in the gill arch, and the primary arteries in each primary lamella. This pathway includes the central venous sinus of the primary lamella, several small veins and is finally connected with the branchial veins. 3 — The lack of connections between afferent primary arteries and cvs in the trout and the perch makes impossible a direct blood flow from the afferent to the efferent artery (shunt). In the eel connections between cvs and both afferent and efferent arteries do not mean that a shunt is operating according to the pressure gradient.     

The superficial vascular hyaloid system in the eye of the frogs,Rana temporaria and Rana esculenta

Summary The angioarchitecture of the superficial vascular hyaloid system (membrana vasculosa retinae) of the frog eye was studied by means of scanning electron microscopy of vascular corrosion casts. The terminal vessels form a single-layered sheath intimately adjacent to the vitreal side of the avascular retina. The hyaloid system is subdivided by the ventral venous trunk into three central areas: the dorsal, the temporo-ventral, and the naso-ventral area. Toward the ora serrata, the hyaloid system is bordered by an arterial ring, and by nasal and temporal venous branches forming more or less complete hemicircles. A vascular zone composed of several tongue-like sectors establishes an inter-connection between the peripheral vascular rings and the central areas of the fundus. The arterial blood is supplied from the arterial ring. The drainage of the hyaloid system is provided via two routes: (1) the Y-shaped ventral trunk collects blood from the central areas, (2) the two peripheral venous branches drain the tongue-like sectors. The vessels within the dorsal area follow preferentially a dorso-ventral meridional direction. This densely capillarized territory corresponds in localization to the area centralis retinae. The ultrastructure of microvessels of the hyaloid system is characterized by features typical for capillaries of the central nervous system.     

Changes in osmotic water permeability of the eel gills during seawater and freshwater adaptation

Summary Changes in osmotic water permeability of the isolated gills of the Japanese eel,Anguilla japonica were studied during transfer to seawater or to fresh water. The water permeability increased gradually during the course of seawater transfer and attained a maximal level after 2 weeks. The water permeability of the freshwater eel gills was reduced when calcium ions were added to the incubation medium at a concentration of 1 mM, where-as no effect of the ion was observed on the gills of the seawater-adapted eel even at a higher concentration (10 mM). In contrast to seawater transfer, the water permeability decreased to a low level almost immediately (3 h) after transfer from seawater to fresh water. The acute reduction of the water permeability was also seen in the gills of the hypophysectomized eel after transfer to fresh water.The gradual increase in the gill water permeability during seawater transfer is correlated with an increase in the number of chloride cells. In scanning electron microscopy, chloride cells of seawater-adapted eel gills exhibit a pit-like structure, which was larger than in the freshwater eel. On transfer from seawater to fresh water, the pit diameter became smaller within 6 h. Hypophysectomy did not affect the change in gill surface structures during transfer to fresh water. The junctions between the chloride cells of seawater eel gills are reported to be of the leaky type. The parallel change in osmotic water permeability and in pit size of the chloride cells during seawater or freshwater transfer or after hypophysectomy suggests that these cells could provide a major route of water as well as ion movement.This paper is a portion of a thesis presented to Hokkaido University by t. Ogasawara in partial fulfilment of the requirements for Doctor of Fisheries     

RING finger, B-box, and coiled-coil (RBCC) protein expression in branchial epithelial cells of Japanese eel, Anguilla japonica.

An RBCC (RING finger, B-box, and coiled-coil) protein was identified that belongs to the superfamily of zinc-binding proteins and is specifically expressed in the gill of eel, Anguilla japonica. Euryhaline fishes such as eels can migrate between freshwater and seawater, which is considered to be accomplished by efficient remodeling of the architecture and function of the gill, a major osmoregulatory organ. To identify molecules involved in such adaptive changes, we performed differential display using mRNA preparations from freshwater and seawater eel gills and obtained an RBCC clone among several differentially expressed clones. The clone encoded a protein of 514 amino acid residues with structural features characteristic of the RBCC protein; we therefore named it eRBCC (e for eel). eRBCC mRNA was specifically expressed in the gills with a greater extent in the gills of freshwater eels. Immunohistochemistry revealed that the expression of eRBCC is confined to particular epithelial cells of the gills including freshwater-specific lamellar chloride cells. The RING finger of eRBCC was found to have a ubiquitin ligase activity, suggesting an important regulatory role of eRBCC in the remodeling of branchial cells.     

A morphological study on gills of the brown shrimp, Penaeus aztecus

The gills of Penaeus aztecus were examined by light and electron microscopy. They are dendrobranchiate, consisting of a central axis with biserially arranged branches that subdivide into bifurcating filaments. A septum divides the lumina of these structures into afferent and efferent channels. Hemolymph from the sternal sinus flows through the afferent channels into the filaments where it is directed into the efferent channels and finally to the pericardial cavity. In addition to these channels, numerous blood vessels permeate the gill. The cuticle covering the gill overlies a thin epithelium which is separated from hemolymph by a basal lamina. The epithelium, which is active in cuticle secretion, has a series of pillar processes that form subcuticular lacunae. The apical membranes of epithelial cells become folded in shrimp exposed to hypo- and hyperosmotic salinities. Granular cells that contain elaborate Golgi apparati and several types of granules are present throughout the gill. Nephrocytes resembling glomerular podocytes line the efferent channels. A large nerve traverses the septum in the axis.     

The morphology and vasculature of the lungs and gills of the soldier crab,Mictyris longicarpus

The five gill pairs of Mictyris longicarpus have the lowest weight specific area reported for any crab. The cuticle of the gill lamellae is lined with epithelial cells which have structural features characteristic of iontransporting cells. Pillar cells are regularly distributed in the epithelium and serve to maintain separation of the two faces of the lamellae. The central hemolymph space is divided into two sheets by a fenestrated septum of connective tissue cells. The dorsal portion of the marginal canal of each lamella receives hemolymph from the afferent branchial vessel and distributes it to the lamella while the ventral portion of the canal collects hemolymph and returns it to the efferent branchial vessel. The lung is formed from the inner lining of the branchiostegite and an outgrowth of this, the epibranchial membrane. Surface area is increased by invagination of the lining which forms branching, blind-ending pores, giving the lung a spongy appearance. The cuticle lining the lung is thin and the underlyng epithelial cells are extremely attenuated, giving a total hemolymph/gas distance of 90–475 nm. Venous hemolymph is directed close to the gas exchange surface by specialised connective tissue cells and by thin strands of connective tissue which run parallel to the cuticle. Air sacs are anchored in position by paired pillar cells filled with microtubules. Afferent hemolymph is supplied from the eye sinus, dorsal sinus, and ventral sinus. Afferent vessels interdigitate closely with efferent vessels just beneath the respiratory membrane. The two systems are connected by a “perpendicular system” which ramifies between the airways and emerges to form a sinus beneath the carapace and then flows back between the air sacs to the efferent vessels. The afferent side of the perpendicular system is the major site of gas exchange. Efferent vessels return via large pulmonary veins to the pericardial cavity. P_aO₂ levels were high (95.5 Torr), indicating highly efficient gas exchange.     

Substance P in the blood plasma in hypophysial portal vessels

The aim of the present study was to check if Substance P (SP) is released from the hypothalamus into the hypophysial portal vessels and by this route exerts its direct influence on the adenohypophysis. For this purpose SP radioimmunoactivity was assayed in the blood plasma collected from hypophysial portal vessels and from the cephalic end of the external jugular vein. The SP levels in blood plasma collected from hypophysial portal vessels and from the jugular vein do not differ significantly. Neither does application of a noxious factor, such as bilateral femoral bone fracture, change significantly the SP level in the blood plasma from portal vessels and from the jugular vein. Hypoxia seems to increase the SP level in portal blood plasma and may be followed by its decrease. It is concluded that hypothalamic SP is not released into the hypophysial portal vessels under normal conditions and its direct influence on the adenohypophysis is not mediated this way.     

Morphometric analysis of the gills of the European eel, Anguilla anguilla

The gills of the European eel, Anguilla unguilla L. were analysed morphometrically. Fresh (unfixed) gills and resin-replica casts of the branchial vascular system were examined. The total gill surface area was found to be proportional to (body mas) 0-715 for fish of between 60 and 1 160 g. This relationship between gill surfxe area and body mass was maintained irrespective of a reduction in body mass produced by fasting. Vessel dimensions were obtained from the vascular casts. Calculations made using these values suggest that the major sites of gill vascular resistance lie at the level of the afferent lamellar arterioles and the secondary lamellae.     

Die Vaskularisation der Kiemen von Myxine glutinosa L. (Cyclostomata)

The angioarchitecture of the gills in Myxine glutinosa L. was studied by scanning electron microscopy of vascular corrosion casts (methylmethacrylate). It was found that the afferent branchial artery may be connected to the sinus peribranchialis by a papilla. The sinus is connected to delicate vessels and sinuses, which are interposed between meridionally arranged radial arteries. These delicate vascular formations continue into the interior of the gill and form a plexus on both poles of the gill folds. Light and scanning electron microscopical studies on the vascular endothelium of the afferent vessels of the gill lamellae reveal rounded endothelial cells, which are characterized by a high content of granula, by long cellular processes and by bridge-formations towards neighbouring cells. Supporting columns within the vascular system of the lamellae were found to be set up by several spirally arranged cells. SEM observations reveal goblet cells and numerous superficial epithelial cells with various numbers of microvilli and microridges forming the epithelial surface of the gill folds.     

A radiological study of the central circulation in the lungfish, Protopterus aethiopicus

The dipnoan heart is only in part structurally developed to support a separated circulation in pulmonary and systemic circuits. In the present investigation biplane angiocardiography has been used to describe the extent of such a double circulation and the factors which may modify it in the African lungfish, Protopterus aethiopicus. Contrast injections in the pulmonary vein revealed a clear tendency for aerated blood returing from the lungs to be selectively dispatched to the anterior branchial arteries giving rise to the major systemic circulation. Contrast injections in the vena cava delineated the sinus venosus as a large receiving chamber for systemic venous blood. Contraction of the sinus venosus discharged blood into the right, posterior part of the partially divided atrial space. Contrast injection in the pulmonary vein showed that vessel to pass obliquely from right to left such that blood was emptied distinctly into the left side of the atrium. During contraction the atrial space tended to retain a residual volume in its anterior undivided part which minized mixing. Ventricular filling occurred through separate right and left atrio-ventricular connections. Right-left separation in most of the ventricle was maintained by the partial ventricular septum, the trabeculated, spongelike myocardium and the mode of inflow from the atria. Mixing in the anterior undivided portion of the ventricle during the ejection phase was slight due to a streamlined ejection pattern. The outflow through the bulbus cordis occurred in discrete streams which in part were structurally separated by well developed spiral folds. In the anterior bulbus segment the spiral folds are fused and make completely separate dorsal and ventral outflow tracts. The ventral bulbus channel provides blood to the three anterior branchial arteries. The second and third branchial arteries are large and represent direct shunts to the dorsal aorta. The fourth and fifth branchial arteries are gill bearing and receive blood form the dorsal bulbus channel. The most posterior epibranchial vessels give rise to the pulmonary arteries.     

Non-respiratory blood vessels in Latimeria gill filaments

A study of the blood pathways within the gills of Latimeria has been carried out using light and transmission electron microscopy. Clear evidence has been found for the presence of a secondary non-respiratory circulation in addition to the well-established respiratory pathway through the gill lamellae. All essential components of this system have been observed and have the same relationships and basic structure as comparable secondary systems in actinopterygian and elasmobranch fishes. These include a central venous sinus (CVS), arterio-venous anastomoses (AVAs) and central filament arteries (CFAs). AVAs connect both arterial vessels of the primary circulation and CFAs of the secondary circulation to the CVS. The latter contained many red blood cells. The presence of this secondary circulation in Latimeria gills contrasts with the situation in the gills of the three living genera of lungfishes where a system possessing the essential features of the tetrapod lymphatic vessel system has been recognized. No suggestions of a true lymphatic vessel system were observed in Latimeria. Other features of gill and vascular anatomy in Latimeria show its closer relationship to dipnoans than other groups of living fishes but evidence derived from this study of the secondary circulation clearly supports the view that the Dipnoi rather than Latimeria represent the living fishes most closely related to the tetrapods.     

Alternative venous outflow vessels in microvascular breast reconstruction

The lack of adequate recipient vessels often complicates microvascular breast reconstruction in patients who have previously undergone mastectomy and irradiation. In addition, significant size mismatch, particularly in the outflow veins, is an important contributor to vessel thrombosis and flap failure. The purpose of this study was to review the authors' experience with alternative venous outflow vessels for microvascular breast reconstruction. In a retrospective analysis of 1278 microvascular breast reconstructions performed over a 10-year period, the authors identified all patients in whom the external jugular or cephalic veins were used as the outflow vessels. Patient demographics, flap choice, the reasons for the use of alternative venous drainage vessels, and the incidence of microsurgical complications were analyzed. The external jugular was used in 23 flaps performed in procedures with 22 patients. The superior gluteal and transverse rectus abdominis musculocutaneous (TRAM) flaps were used in the majority of the cases in which the external jugular vein was used (72 percent gluteal, 20 percent TRAM flap). The need for alternative venous outflow vessels was usually due to a significant vessel size mismatch between the superior gluteal and internal mammary veins (74 percent). For three of the external jugular vein flaps (13 percent), the vein was used for salvage after the primary draining vein thrombosed, and two of three flaps in these cases were eventually salvaged. In three patients, the external jugular vein thrombosed, resulting in two flap losses, while the third was salvaged using the cephalic vein. A total of two flaps were lost in the external jugular vein group. The cephalic vein was used in 11 flaps (TRAM, 64.3 percent; superior gluteal, 35.7 percent) performed in 11 patients. In five patients (54.5 percent), the cephalic vein was used to salvage a flap after the primary draining vein thrombosed; the procedure was successful in four cases. In three patients, the cephalic vein thrombosed, resulting in two flap losses. One patient suffered a thrombosis after the cephalic vein was used to salvage a flap in which the external jugular vein was initially used, leading to flap loss, while a second patient experienced cephalic vein thrombosis on postoperative day 7 while carrying a heavy package. There was only one minor complication attributable to the harvest of the external jugular or cephalic vein (small neck hematoma that was aspirated), and the resultant scars were excellent. The external jugular and cephalic veins are important ancillary veins available for microvascular breast reconstruction. The dissection of these vessels is straightforward, and their use is well tolerated and highly successful.     

Venous drainage in the reverse forearm flap

Venograms were performed in three cases of reverse forearm flap. The "crossover pattern" of the communicating branches between the two venae comitantes and the "bypass pattern" of the collateral branches of each vein have been demonstrated. These factors may explain the reverse drainage of venous blood, even though the valves of the vein are intact. Notably, the cephalic vein also shows a good communication with the deep venous system. Thus it can contribute another route for venous drainage in this flap.     

The morphology of the gills of the freshwater African crab Potamon niloticus (Crustacea: Brachyura: Potamonidae): A scanning and transmission electron microscopic study

The gills of the African freshwater crab Potamon niloticus -Ortmann have been investigated by scanning and transmission electron microscopy. Potamon has seven pairs of phyllobranchiate gills contained in the branchial chambers. From the central axis of the gills arise bilaterally situated thin flaps, the lamellae. The afferent branchial vessel (the epibranchial vessel) is located on the dorsal aspect of the gill arch and the efferent vessel (the hypobrancial vessel) on the ventral side. Between these two blood vessels, the blood percolates through the lamellar vascular channels where it is oxygenated. The lamellae consist of an epithelial cell layer covered by a thin cuticle which consists of tightly fused but distinct layers. The epithelial cells approach each other at regular intervals and fuse in the middle of the lamellar sinus delineating the vascular channels. Apical profuse membranous infoldings and numerous mitochondria characterize the epithelial cells, features typical of cells involved in active transport of macro- and micromolecules. In Potamon , however, there were no distinct gas exchange and osmoregulatory regions of the gills. On average, the cuticle was 0.78 μm thick while the epithelial cell was 6 μm. Cells that were morphologically similar to the renal glomerular podocytes of the vertebrates were observed in the efferent gill vessel of Potamon. These cells have been said to be phagocytic and may play an important defensive role in the crustaceans. Although basically the morphology of the gills of Potamon is similar to that of the other decapods, fine structural differences were evident as would be intuitively expected in a group of animals that has undergone such remarkable adaptive radiation.