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At least 19 recordsLinked to original sources
PubMed2024

Seasonal hydrological dynamics affected the diversity and assembly process of the antibiotic resistome in a canal network.

The significant threat of antibiotic resistance genes (ARGs) to aquatic environments health has been widely acknowledged. To date, several studies have focused on the distribution and diversity of ARGs in a single river while their profiles in complex river networks are largely known. Here, the spatiotemporal dynamics of ARG profiles in a canal network were examined using high-throughput quantitative PCR, and the underlying assembly processes and its main environmental influencing factors were elucidated using multiple statistical analyses. The results demonstrated significant seasonal dynamics with greater richness and relative abundance of ARGs observed during the dry season compared to the wet season. ARG profiles exhibited a pronounced distance-decay pattern in the dry season, whereas no such pattern was evident in the wet season. Null model analysis indicated that deterministic processes, in contrast to stochastic processes, had a significant impact on shaping the ARG profiles. Furthermore, it was found that Firmicutes and pH emerged as the foremost factors influencing these profiles. This study enhanced our comprehension of the variations in ARG profiles within canal networks, which may contribute to the design of efficient management approaches aimed at restraining the propagation of ARGs.

Seasons↗
PubMed1977

The fine structure of human digital arterio-venous anastomoses (Hoyer-Grosser's organs).

Hoyer-Grosser's organs were studied in human digital biopsies. The fine structure of both the supplying arteries and collecting veins was found to be inconspicuous. Endothelial cells in the AV canals form a continuous layer. They are characterized by their rich content of specific organelles (Weibel-Palade bodies), especially in the venous segments. The epitheloid zone is composed of a variety of ramified smooth muscle cells (RSM). These appear either dense, when well provided with bundles of myofilaments, or clear, when including only a few myofilaments. The nuclei of dense RSM show condensed chromatin, while those of clear RSM are larger with loose chromatin texture. In addition, all transitional forms occur. Cell organelles are rarely seen within all types of RSM. The cytoplasmic processes reach other as well as endothelial cells. The preservation of our material did not allow observation of specialized membrane contacts in these zones. All RSM are invested with a regular basal lamina and well provided with surface vesicles. Profiles of free basal lamina material and faint collagen (argyrophil) fibers are seen in the wide intercellular spaces. RSM poor in myofilaments are interpreted to represent "epitheloid cells" of light microscopy. Their number constantly decreases from the arterial segment of the AV canal to the venous segment. Here the cytoplasmic processes of RSM become less pronounced and the wall of the anastomotic segment continuously changes to that of the collecting vein. Dense RSM rich in myofilaments are compared with pacemaker cells found inthe ureter. Both internal and external elastic membranes are absent in AV canals. A dense network of unmyelinated nerve fibers is found in the adventitial layer of the AV canal, especially in its arterial segment. The axons branch out from small dermal nerves which also contain two or three myelinated axons. The myelin sheaths terminate where the axons reach the adventitia of the AV canals. Axon varicosities filled with mitochondria are thought to be terminals of myelinated axons and are interpreted as receptory. Axon varicosities with synaptic-type vesicles are assumed to be terminals of sympathetic and para sympathetic fibers. All axon profiles are confined to the adventitial layer of the anastomotic segment.

Arteriovenous Anastomosis↗
PubMedDate not supplied

[Coelomomyces psorophorae Couch, 1945 (Blastocladiales-Coelomomycetaceae), a parasite of Aedes detritus (Haliday, 1833) (Diptera-Culicidae) in the Camargue (author's transl)].

The Phycomycete, Coelomomyces psorophorae Couch, 1945, was found in the south of France in the salt marsh mosquito Aedes detritus (Haliday, 1833). The fungus invades the ovarioles but leaves the follicules intact. At high magnification, (using a scanning electron microscope), the crater-form punctuations adorning the sporangium were seen to result from openings (ostioles) of the network of small canals that traverse the external wall.

Aedes↗
PubMed1977

[Role of the aqueous factor in the epidemiology of dysentery].

Analysis of the dynamics and territorial distribution of bacterial dysentery morbidity during 1959-1973 in the Dagestan ASSR demonstrated that the epidemically unfavourable conditions were largely connected with the use of water in open water bodies for domestic purposes and swimming as well as a wide network of irrigation canals. Persistence of the water factor in the dysentery epidemiology was connected with the ever increasing contamination of water in open water bodies and neglect of sanitary-hygienic requirements of the water supply to population of pertinent and sanitary laws.

Dagestan↗
PubMed1976

[Cerebrospinal fluid bearing channels of the pia meter].

The pia mater of the human brain hemispheres has liquor canals which form a continuous network communicating with the cisterns of the brain base. The wall of the liquor canals is formed by a fibro-collagenous framework covered from two sides with the arachnoidendothelium. In the canal walls there are openings, through which the lumens of the canals communicate with the lumens of alveoli. The liquor canals are divided into the circulatory and excretory ones. The circulatory canals are disposed in the depth of the cerebral sulci, the secretory canals--on the surface of the convolutions. The liquor moves along the circulatory canals from the cisterns of the brain base onto the surface of cerebral hemispheres. Excretory canals adjoin the arachnoid membrane which is part of its wall (the "roof"). In the "roof" of the liquor canals the fibrocollagenous basis and the number of layers of the arachnoid--endothelium are reduced, the intercellular spaces between the cells of the arachnoidendothelium are dilated. Through the roofs of the liquor canals the liquor is excreted from the subarachnoid space into the subdural space. Inside the liquor canals there are arteries of the pia mater hung up to the canal walls by trabeculae (cords) of a dense connective tissue.

Humans↗
PubMedDate not supplied

The importance of the perianal connective tissue in the surgical anatomy and function of the anus.

The anatomy of the perianal connective tissue has been reviewed. The most important element is the conjoined longitudinal coat, the axis of the connective-tissue system. Fibers of the longitudinal coat penetrate the internal and external sphincter, interlacing with each other as well as the perimysium and endomysium and forming a fibroelastic network. The fibers and bundles of the internal and external sphincters lie in the meshes of this network with innumerable attachments to it. The fibroelastic network continues through the perianal fat to the pelvic wall and is connected to the lower levator fascia and the perianal skin, insuring the firm anchoring of the anus. During sphincter contraction the fibroelastic network moves together with the sphincters. Thus, the sphincter function is the integration of the contraction of the muscle fibers attached to the web. The elastic elements of the network pull the anal canal slightly apart, but the muscle tone overcomes this and keeps the anus closed. Surmounting the elasticity of the web causes the muscle function to be elastic as well. Surgical procedures such as stretching, transecting the sphincters, whether sharply or gradually, can lead to scar formation with loss of elasticity or mobility in that part of the sphincter and secondary impairment of function.

Anal Canal↗
PubMed1976

Preparation of fossil bone specimens for scanning electron microscopy.

A method is described for preparing fossil bone specimens for scanning electron microscopy. To obtain bone surfaces suitable for study, material was embedded in Epon 812 and selected faces exposed by grinding were subjected to controlled etching with a 4:1 mixture of 5% HNO3 and 1% OsO4. Surfaces thus prepared were further processed by the so-called clearing replicas technique. As a result of this procedure the bone surfaces revealed a network of anastomosing vascular canals the innter surface of whose walls could be examined in the scanning electron microscope. By etching extremely thin ground sections of bone stuck to plastic tape the contents of vascular canals as well as osteocytes can be isolated. This method ensures the good preservation of spatial relations between bone elements essential for studies of fossil bones, which are sometimes very brittle.

Animals↗
PubMed1977

Schlemm's canal after trabeculo-electropuncture (TEP).

The Schlemm's canals of two patients were examined histologically and electron-microscopically. The first patient had a tumor of the choroid. An electroprobe was inserted into the Schlemm's canal and then removed. In this eye, nearly all septa and almost the entire endothelial layer of the lumen were destroyed in the area of the inserted probe. The second tissue sample came from a patient who had had TEP surgery 2 years earlier and whose intraocular pressure had increased again. The preoperative gonioscopic examination showed an opening in the trabecular network, with blood evading from Schlemm's canal. Histologically, an opening approximately 50 micron wide, lined with endothelium, was found in the trabecular network. The lumen of the canal existed only in a section approximately 500 micron long. Elsewhere the inner and outer walls of the Schlemm's canal adhered to each other. In the area of this 500 micron long section of the canal, only one collector channel could be found. Thus, the insufficient decrease in intraocular pressure after operation can be explained by the side-effects of the insertion of the electroprobe into the Schlemm's canal.

Choroid Neoplasms↗
PubMed1976

[Ultramicroscopic studies on the drainage system of the human corpus luteum].

The granulosa lutein cells of the human corpus luteum have a specialized system of drainage with a particularly formed extracellular space, by which the steroids pass into the capillary vessels. The extracellular space consists of two partial systems: First one finds, similar to the bile capillaries of the liver, lacune-like widnings of the intercellular space, where numerous microvilli of the lining cells are to be found and which are lined by desmosomes and invaginations of the cell membrane. Second there exist relatively wide canals limited by a granular membrane forming a network of their own among the lutein cells. Both systems contact without direct communication. We believe that first the steroids pass into the intracellular lacunes by diffusion or active transport from where they reach the membrane-lined canals by help of the network they pass on to the pericapillar space from where they diffuse into the blood vessels.

Adult↗
PubMed1976

[Electron microscopic study of the rat submaxillary gland during development].

Cytological changes in the submaxillary glands of rat embryos of the 14th-21st days of the intrauterine development and of 7-day-old rats were studied electron microscopically. The cytoplasm of the salivary gland primordium cells of the 14-day embryo was found to possess multiple polysomes, the canals of the granular cytoplasmic network (GCN) being solitary. The latter elongated in the process of embryonic development, and later predominant development of GCN was observed in basal portions of the acinar cells. At early stages of the gland development the GCN was often observed to approximate mitochindria. The laminar complex in the course of embryonic development enlarges its size and at later stages it has a well differentiated appearance in the acinar cells. Secretory inclusions make their appearance in the forming cells of acinuses long before birth, the composition of the embryo gland secretion being somewhat different from that of adult animals. Differentiation of acinuses and striated parts of the salivary tubules is well pronounced in the embryonic period while no signs of appearance of granular portions of the salivary tubules are observed both in light and electron microscopy either in embryos or in 1-week-old rats.

Animals↗
PubMed1979

Somatostatinergic nerves in the cervical spinal cord of the monkey.

Somatostatinergic nerves in the spinal cord of the monkey were investigated utilizing immunohistochemistry with various antibodies against synthetic somatostatin. In contrast to earlier investigations, it is shown that somatostatinergic nerve endings occur in most of the areas of the grey matter of the spinal cord. The somatostatinergic axons are, however, characteristically distributed in three main regions: (1) Densely-packed endings are seen in lamina II of the substantia gelatinosa, forming a crescent-shaped pattern in the columna dorsalis. Somatostatin immunoreactivity is also seen in lamina I and in the Lissauer tract. (2) A fine network of fibers is observed around the central canal; the endings are concentrated on special cell bodies. Some single perikarya are also stained in this region. (3) A loose network of single fibers is found ending on perikarya of the columna lateralis or ventralis. The perikarya of the nerve axons, with the exception of those terminating in the columna dorsalis, have as yet not been identified. In order to better understand the somatostatinergic system of the spinal cord, these newly-detected somatostatinergic nerves must be studied and their exact pathways analyzed.

Animals↗
PubMed1979

Cortical circulation of long bones.

Intravascular injections of India ink in the femora of adult dogs revealed the existence of two distinct vascular systems in the cortex. One courses through the entire thickness of the cortex and is a regular, longitudinal network of uniform capillaries which is in continuity with the periosteal and endosteal networks. Once the haversian systems form a second network appears, radiating from the bone marrow. That system, primarily transverse, anastomoses in the haversian canals with the capillaries of the first system. Therefore, the merging of the two networks occurs primarily in the middle layer of the cortex. The direction of the arterial blood flow in the mature animal is predominantly centrifugal, while the venous drainage is centripetal. In the immature animal, the contribution of the periosteal network is much greater. Because the two cortical systems are profusely anastomosed with each other and with the periosteal and endosteal circulatory networks, the blood can flow in either direction, depending on physiological conditions.

Animals↗
PubMed1978

Use of lyophilized dura in aural surgery.

Lyophilized dura was utilized in chronic ear surgery to cover raw promontory surfaces, to stabilize the reconstructed ossicles, to raise the posterior insertion point of the grafted drum after canal wall removal, and to fortify the soft posterior canal wall. In 3 guinea pigs, lyodura was also placed in the bulla and studied 6, 12 and 16 months later. In 6 months of time, lyodura had become covered with normal epithelium and in 12 months of time, the greatest part of the lyodura was resorbed from the middle ear, normal epithelium having developed. In the canal wall area, resorption is slower and collagenic dural network is clearly recognizable even after a period of 24 months. Lyophilized dura contains no irritating material and is considered to be a versatile and useful material in chronic ear surgery.

Animals↗
PubMed1977

Histopathology on testicular involvement of leukemia with an emphasis on lymphatics.

The human testes in cases of malignant hematopoietic tumors, especially of leukemia, were histologically examined to characterize the mode of leukemic infiltration in comparison with that of malignant lymphoma. Materials were obtained from 56 autopsy cases, composed of 47 of leukemia, 7 of reticulum cell sarcoma and 2 of lymphosarcoma. Leukemic infiltration was confirmed in 43 (19%) of all leukemic cases and the pattern was divided into three types; diffuse, patchy and perivascular. A high grade infiltration was most common in lymphocytic leukemia. The testicular involvement was unexceptionally bilateral with occasional differences in the grade of infiltration, slight to moderate. There was no regional difference in incidence of leukemic infiltration in the testicular interstitium. A thin-walled canal located closely between the proper lamina of seminiferous tubules and the interstitial cell cluster was suggested to be lymphatics, which were extremely irregular in shape and occasionally did not have endothelium. Therefore human testicular lymphatics might not be a constant canal system, but rather akin to narrow tissue space. A network of argyrophilic fibers was pronounced in the lesion of leukemic infiltration. The frequency and grade of an involvement of the testes in malignant lymphoma were lower and lesser than those in leukemia.

Adolescent↗
PubMed1978

Methods of preparation of fossil bone samples for light and transmission electron microscopy.

The methods described make possible the preparation of fossil samples for light nad transmission electron microscopy. To obtain good images with ground sections of bone, both the grinding process and classical bone staining techniques were modified, the latter by staining already made ground sections. Ground sections of suitable thickness were etched with a 4:1 mixture of 5% HNO3 and 2% OsO4 at a lowered temperature, thereby obtaining isolated osteocytes with a complete network of processes. Using the same method with thicker ground sections, the contents of vascular canals were isolated. The contents retained spatial relations permitting complete reconstruction of the vascular system of the bone in question. The isolated osteocytes, the vascular canal contents, and the isolated remnants of the intercellular organic part of this bone, subsequently embedded in Epon 812 and in methacrylate, made possible sections suitable for detailed analysis of the image of the surfaces of these elements. Polished surfaces of the fossil bone were replicated by the so-called clearing replicas technique adapted to fossil bone. The latter facilitated analysis of the ultrastructure of the surfaces of the vascular canals, isolated osteocytes and their processes, and analysis of the immediate proximity of these elements, since the technique preserves the mutual spatial relations intact.

Animals↗
PubMed1976

[Hepatic echo-angiostructure: echo-anatomical study of the intraparenchymatous canal structures (author's transl)].

Hepatic echo-angiostructure: echo-anatomical study of the intraparenchymatous canal With a suitable technique (real time, grey scale) hepatic ultrasonography is able to display intraglandular ductal elements: portal veinous network, supra-hepatic veinous network, and, if enlarged intrahepatic biliary tree. A careful echoanatomic study is necessary to identify the enlarged biliary network in case of obstructive jaundice; such a study is also necessary not to confuse normal ductal structures, insufficiently displayed, with pathological reflections - a rather frequent hazard with conventionnal techniques.

Bile Ducts, Intrahepatic↗
PubMed1977

Microvascular injection studies in rubeosis iridis and neovascular glaucoma.

Microvascular silicone injection, tissue clearing, and histologic examination were used to demonstrate the origin, distribution, and interconnections of newly formed iris and chamber angle blood vessels in four eyes with rubeosis iridis and neovascular glaucoma associated with diabetic retinopathy and central retinal vessel occlusion. The newly formed iris vessels that formed either a tight, evenly distributed (diabetic) or loose, irregularly distributed (central vessel occlusion) network in the iris originated from the normal iris arteries that were branches of either the major arterial circle or of the perforating branches of the anterior ciliary arteries, and drained into the normal iris and ciliary body veins and occasionally into the paralimbal episcleral veins. These newly formed iris vessels appeared to shunt intravascular fluid from arteries to veins. The newly formed anterior chamber angle vessels that formed tufts and arcades at the trabecular meshwork also originated from the roots of the iris arteries and the ciliary body arteries and connected with the peripheral neovascular iris network. In addition, the circumferentially running angle vessels that coursed within the trabecular meshwork branched into and coursed within a fibrosed Schlemm's canal and into two of its intrascleral collector channels. No open communication between these newly formed vessels and the Schlemm's canal-aqueous outflow system was seen.

Arteriovenous Anastomosis↗