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Results for “Meanders”

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At least 487 records · Page 27Linked to original sources

PubMed1989

[Study on the radiation effects toward function and vessels of parotid gland in rat].

The effect of irradiation on the parotid gland was determined from 99mTc-pertechnetate (99mTcO4-) uptake and the course of vessels in the parotid gland, by investigating the uptake and excretion of 99mTcO4- in 60Co-gamma ray-irradiated rat parotid gland and ovserving the course of blood vessels and the histological changes. 1. In the uptake test, radiation activity of 99mTcO4- taken into the parotid gland per unit weight was the highest three days after irradiation for both 10 Gy (1.68 x 10(5)cpm/g) and 50 Gy (2.05 x 10(5)cpm/g); however, it began to decrease gradually at 7 days after irradiation. 2. In the clearance test, as in the uptake test, the radiation activity of 99mTcO4- per unit weight remaining in the parotid gland after stimulation of secretion, was high at 3 days after irradiation for both 10 Gy and 50 Gy (0.86 x 10(5), 1.28 x 10(5)cpm/g, respectively) and 7 days (0.88 x 10(5), 1.29 x 10(5)cpm/g) after irradiation, and gradually decreasing thereafter. 3. Stimulation-secretion coefficients determined from the ratio of uptake and clearance of 99mTcO4- were lower in all groups with irradiation than in the group without irradiation, with especially low values at 7 and 14 days after radiation. Thus, parotid function declined after irradiation. 4. With respect to the effect of irradiation on blood vessels, mild dilation was observed at 10 Gy at 3 and 7 days after irradiation, then constriction and meandering were noticed. Such changes were greater at 50 Gy than at 10 Gy. 5. Histological changes appeared 6h after irradiation in the 10 Gy- and 50 Gy-irradiation groups. Derangement of cells in the terminal parts, dilation of conduits, and proliferation of connective tissue were observed from 3 days after irradiation. 6. The periodic aid-Schiff (PAS) reaction was decreased in the 10 Gy- and 50 Gy-irradiation groups, with few PAS-positive cells at 28 days after irradiation. In conclusion, the decline in parotid function after 10 Gy- and 50 Gy-irradiation was related to histological changes in the vascular system and glandular tissues.

Animals↗

PubMed1989

[Juvenile Sandhoff disease with local panatrophy--a case report].

A case of juvenile Sandhoff disease with Gowers' local panatrophy was reported. A mentally retarded 39 year-old man had been noticed to have localized skin atrophy on the right leg since 7 years of age, and was also aware of the atrophy of his right leg since his junior high school age. His parents were first cousins. He had multiple localized atrophic skin lesions on the right side of his nape, the right side of lower back, and the right thigh. These skin lesions did not show any signs of sclerosis. Although he was mentally retarded (IQ=44), the neurological examination was normal including funduscopy. Histological examination of the atrophic skin le led that the epidermal basal layer was hyperpigmented and that the dermis and subcutaneous fatty tissue were extremely atrophic. The nerves meandered across the dermis and subcutaneous tissue, and had membranous lipid storage cytosomes in the axon and Schwann cells. Biochemical studies revealed marked deficiency fo leukocyte hexosaminidase activity. Total hexosaminidase activity was decreased to 18% of normal controls, and hexosaminidase B activity was completely deficient. Other lysosomal enzymes in leukocytes were normal in activities. Both parent showed intermediate levels of leukocyte hexosaminidase A and B activities. Electron microscopy analysis of a rectal biopsy specimen showed neuronal accumulation of dense osmophilic deposits, as well as membranous cytoplasmic bodies in Meissner's plexus. On the basis of the patient's age at onset and the above findings, the patient was diagnosed to have juvenile Sandhoff disease. The local panatrophy observed in the present case could be the result of the accumulation of GM2-ganglioside in autonomic nervous system, and may well be a new clinical feature of GM2-gangliosidosis.

Adult↗

PubMedDate not supplied

[Aging changes in conjunctival blood vessels].

The relation of the changes in the conjunctival blood vessels to the age were studied in a group of 217 persons aged 20 to 79 years. All persons suffering from arterial hypertension, diabetes, systemic diseases and manifested forms of arteriosclerosis were excluded. It has been proved that examination of the conjunctival blood vessels by means of the slot-lamp facilitates the study of the changes in the microscopic blood vessels in relation to the age. Most conspicuous was the increase of the meander course of the blood vessels, also the increasing number of blood vessels is more frequent in the group of older persons. Clusters of vessels and a narrowing of the diameter of the arterioles was seen only in persons over fifty years of age. The "upright" course of the arterioles was found only in individual cases and without any special dependence to age. Sacculations on the small veins and microaneurysms on the arterioles were not observed in any of the examined group of healthy persons.

Adult↗

PubMedDate not supplied

Removal of purgeable organic chlorine compounds by activated carbon adsorption.

The increasing demand for drinking water in the city of Cologne could no longer be met solely by ground water resources. A group of wells was placed in a meander of the Rhine River south of Cologne in order to draw bank-infiltrated ground water from the river. Geohydrological conditions at that location assure that the pumped raw water is mainly bank-infiltrated water from the Rhine River. The relatively long underground passage, of about 600 m, provides significant pretreatment of the river water.

Adsorption↗

PubMed1986

[Ischemic colitis after surgery of abdominal aortic aneurysm].

Ischemic colitis following aortic reconstruction for abdominal aortic aneurysm was discussed. The low morbidity rate of postoperative abdominal symptom was recognized significantly when meandering mesenteric artery (MMA) was shown clearly in angiography before surgery. When inferior mesenteric artery (IMA) was patent before surgery, furthermore when IMA was not reconstructed, it is necessary for preventing postoperative ischemic colitis that mean IMA/systemic pressure ratio is above 0.5 or 0.6.

Aged↗

PubMed1985

[Use of absorbable suture material in dermatologic surgery].

Absorbable synthetic suture material (Vicryl, PDS) alone was used for wound closure in 1860 surgical interventions on the skin. The PDS suture is totally inert in intracutaneous tissue, and proved superior to the Vicryl suture. In combination, PDS sutures can also be used intracutaneously as well as conventionally. Additional advantages of absorbable material are the possibility of meandering and everted stitches in continuous intracutaneous sutures, no need for removal in most cases, and avoidance of intracutaneous scar dehiscences because of the good durability of the suture material.

Adult↗

PubMed1979

[The initial stages of formation of the bone centers and the construction of the skeletal organs. The metamorphosing cartilage: Part I].

In connection with the investigation of the ossification center we discussed the significance of the several sites of osteogenesis. In consideration also of anthropometric relations during growth we got the impression that among others the relations to the muscle- and nerve-system are important for development of bones. The insertions of muscles at the diaphysis are in square dimensions respectively linear, in which regions a tendineous osteogenesis occurs, so that muscle and bones may grow together. The organ of growth for diaphysis is the epiphyseal disk und represents real a diaphyseal disk. Above the epiphyseal disk there remains a part, which acts firstly as growing cartilage. Close to it and partly connected with the epiphysis are apophysis, the points of circumscripted insertions of muscles. In this part a metamorphosis takes place, which in connection of the formation of the cavity of the ossification center formate later on the osseal basis of joint cartilage. With retardation and finally the stop of length growth in epiphysis and metaphysis a new area of bone formation is built up in which the ultimate spongiosa becomes formed. During the formation of the cavity of the ossification center dominate degenerative changings of the cells and intercellular-substances. The chondrocyts accumulate in first easily dissolving carbohydrates. The original meandering endoplasmatic reticulum transforms to small vesicular structures and are fragmentated. The partly roundish and bizarre shaped nuclei shows signs of pyknosis. The cells become a longish dense shape with enclosed vesicles and dense structures, there structural elements cannot be more diagnosed. The fibrills originally arranged in a cross-system decrease in diameter and run now almost parallel. Finally they disintegrate to fragments which are mixed with MPS-granules.

Animals↗

PubMed1982

[Angioarchitecture of gliomas. 2. Vessel models from experimental brain tumors in experimental animals].

The paper submits the results of the study of vascular models of experimental brain tumours in 20 Wistar rats and 20 rabbits from inbred races. These were transplantation tumours of the type of the dedifferentiated astrocytomas. First, the authors give a survey of the transplantation technique, the preparation of the vascular models and the advantages and disadvantages of the individual injection methods. The individual findings of the change in the blood supply of the brain, the vascular transformation by the tumour and the new formations of the tumour vessels are described and illustrated by pictures. Signs of true tumour vessels were: I. Caliber fluctuations, vascular occlusions and breaks; 2. Loss of direction property of the vessels, normal division and anastomosing; 3. Insufficiency of the vascular wall with extravasates and short-circuits; 4. Vascular bulgings with formation of pseudoaneurysms, meanders and blood puddles. The individual tumour vessel signs were found in a typical arrangement which permitted a classification of the tumour. Especially in the region of necroses and in the periphery of the tumour, the changes of the tumour vessels could not be strictly differentiated from reactive changes especially in the venous region.

Animals↗

PubMed1980

[Determination of arterial wall thickness variations of vessels in the microcirculation by the ATPase-Quantimet method].

The use of the Quantimet for measurements of structural wall reactions of blood vessels (b.v.), visualized selectively by a modification of the ATPase reaction, requires that changes in wall thickness are not mimicked by differences in deposition of the reaction product, by changes of the b.v. lumen, and/or by b.v. elongations, especially meanderings occurring independently of thickenings of vessel walls and caused solely by increase of the intravascular pressure or by vasoconstriction. The article has substantiated the conclusion that these requirements are fulfilled.

Adenosine Triphosphatases↗

PubMed1984

[Morphometric analysis of the dorsal lateral geniculate body of the laboratory mouse and microphthalmic variants].

The dorsal lateral geniculate nucleus (dLGN) of the mouse (strain 944 with microphthalmus syndrome, P. Hertwig 1942) has been morphometrically investigated. The eyes of the gray littermates develop normally (control animals) while the white littermates show the microphthalmus syndrome (microphthalmic animals). Four male twentyone day old animals were examined. Following perfusion with formaldehyde (diluted 1:4 with H2O) Nissl stained frontal sections were used for classification of neurons. we differentiate between projection neurons (PN) (geniculo-cortical relay neurons) and interneurons (IN). We succeeded in identifying these two cell types using deimpregnated Golgi preparations (Fairén et al. 1977), which were counterstained with methylene blue (0.1%). The neuronal packing density and the ratio PN:IN were conventionally determined using 20 micron thick sections from both control and microphthalmic animals. In both cases this ratio was 12:1 (= 8% IN). Measuring fields distributed in a meander-like manner were selected for estimating the neuronal density. Measuring fields giving equal values were connected. The results show that we can distinguish between 3 regions of dLGN: lateral, medial and caudal. They differ with regard to neuronal packing density, size and structure of the PN. Using 3 micron thick Nissl stained sections from both control and microphthalmic animals the size and structure of PN were automatically determined using the picture processing device "MORPHOQUANT" VEB Carl Zeiss JENA). The distribution pattern of IN is apparently uniform. The microphthalmus syndrome produces a diminished number of pathologically changed retinal fibers. The morphometrically registered findings show that within the dLGN, of the microphthalmus mouse the neuronal packing density increased (diminution of neuropil), the size of PN decreased and their structural density increased (transneuronal dystrophy). Compared with the other parts, the medial part of the dLGN is minimally altered.

Animals↗

PubMed1977

Comparison of microscopic positivity in smears from sputa stained according to Ziehl-Neelsen in different modifications.

Some basic factors influencing the detection of microscopic positivity in the sputa of patients with tuberculosis of the lungs, stained according to Ziehl-Neelsen in various modifications, were studied in 9 laboratories in 5 different countries (Bulgaria, Czechoslovakia, Mongolia, German Democratic Republic and Poland). Each laboratory prepared 200 coded slides from 50 suspect-positive sputa. The slides were stained using four different methods and despatched, without examination, to the next laboratory in the series. A total of 1 800 slides from 450 sputa were thus evaluated and each smear was successively examined by 8 different readers. The study has shown that the result of direct microscopy depends primarily on the individual qualities and attentiveness of the workers evaluating the slides while the remaining factors are less important. Mechanical homogenization of sputa before making the smear, carried out by shaking the sputum with glass beads, had a significant effect on the number of detected mycobacteria while homogenization using soda lye did not influence the positivity in any direction. The detection of mycobacteria after hot staining was significantly higher than after a 2-hour action of carbolfuchsin without heating. Additional staining with picric acid or malachite green had no effect on the amount of bacteria detected and the method of examination (in one line or meander-like on selected spots) was found to be completely unimportant.

Humans↗

PubMed1981

Paracellular route of aqueous outflow in the trabecular meshwork and canal of Schlemm. A freeze-fracture study of the endothelial junctions in the sclerocorneal angel of the macaque monkey eye.

The intercellular junctions of the endothelial cells of the trabecular meshwork and canal of Schlemm were examined with the electron microscope in the macaque monkey eye by both thin-sectioned specimens and the freeze-fracturing technique. The endothelial cells that line the beams of the meshwork are joined by gap junctions and short, isolated strands of tight junction; zonulae occludentes are absent. Thus aqueous humor can freely traverse the patent endothelial clefts of the trabecular meshwork. The endothelial cells of the canal of Schlemm are joined by zonulae occludentes and a small number of minute gap junctions. In 57% of their length, the tight junctions consist of one or two strands; the strands are rarely more than four. They remain preferentially associated with the E-face of the membrane, run parallel to one another, and only exceptionally branch or anastomose. Thus they are provided with free endings and do not form a bidimensional network. As a result of this organization, the zonula occludens is traversed by meandering channels of extracellular space or split pores, which connect the open endothelial clefts on the luminal and tissue fronts of the junction. The frequency of slit pores is 0.134 per micrometer of zonula occludens. They occupy 0.87% of the intercellular boundary and 0.0015% of the area of the endothelium. Estimates of the fluid conductance of the zonulae occludentes indicate that the intercellular clefts of the endothelium of Schlemm's canal filter but a small fraction of the amount of aqueous humor that leaves the anterior chamber through the conventional route.

Animals↗

PubMed1980

A system of atypical catecholamine-containing nerve fibres in the rat iris present after total superior cervical ganglionectomy.

A system of hitherto unknown weakly fluorescent fibres was detected in the rat iris by Falck-Hillarp fluorescence histochemistry after superior cervical ganglionectomy. These long smooth winding (SW)-fibres had a scarce and unusual distribution, forming loops and meandering for long distances with limited branching. Pharmacological tests suggest that they store a catecholamine but differ from adrenergic nerves in lacking an efficient uptake mechanism for amines. SW-fibres reached all parts of the iris and gave rise to few scattered extremely faint green fluorescent, limited plexuses of irregularly bulgy fibres. Suggestions as to the cellular origin of the SW-fibres include the ciliary ganglion and the central nervous system.

Animals↗

PubMed1995

[From research of non-suppressible serum insulin activity to the clinical application of recombinant insulin-like growth factor (rhIGF-I)].

The meandering and sometimes painful journey from the discovery of non-suppressible insulin-like activity in serum to the chemical, biological and physiological characterization and biotechnological production of the two peptide hormones which are responsible for this plasma activity, i.e. IGF-I and IGF-II, is described. IGF-I is the major mediator of most activities of pituitary growth hormone and is therapeutically used for the stimulation of growth in growth hormone-insensitive (Laron) dwarfs and for the treatment of type A insulin-resistant diabetics with non-functional insulin receptors. IGF-I and -II are not only endocrine hormones but also important locally produced peptides that act on cell differentiation during embryogenesis and on the regeneration of tissues during adult life via the autocrine/paracrine pathway. IGF research, chiefly in Zürich, serves as a basis on which to discuss more general aspects of the training of medical doctors and research structures in Switzerland.

Amino Acid Sequence↗

PubMed1994

Comparison of cardiotoxicity of pirarubicin, epirubicin and doxorubicin in the rat.

The authors have examined the cardiotoxic actions of pirarubicin (THP), compared with epirubicin (EPI) and doxorubicin (DXR), on the electrocardiogram (ECG) and myocardial structure in rats. The rats were treated once a week for four weeks with DXR (total dose 10 mg/kg), and then further treated (post-treated) once a week for four weeks with THP, EPI or DXR (total dose 5 and 10 mg/kg). In the ECG study, a prolongation of QaT interval (interval from the upstroke of R wave to the apex of T wave) and a flattening of T wave were observed more severely in the rats post-treated with EPI and DXR than in those treated with THP. Also, a prolongation of QRS duration was observed more prominently in those treated with DXR than with THP and EPI. Histopathologically, a vacuolization and swelling of myocardial cells and an infiltration of mononuclear cells were observed more severely in the rats post-treated with EPI and DXR than in those treated with THP. Furthermore, a meandering of myofibril was observed in those treated with EPI and DXR, but not with THP. These results suggest that the cardiotoxic actions of THP are weaker than those of EPI and DXR and that the replacement of DXR with THP leads to more successful cancer chemotherapy with less cardiotoxicity.

Animals↗

PubMed1994

Morphology and element distribution of magnesium-secreting epithelium: the proximal tubule segment PII of dogfish, Scyliorhinus caniculus (L.).

Proximal tubule segment PII cells of marine elasmobranch fish were studied by transmission electron microscopy of thin sections, and X-ray microanalysis was performed with freeze-dried cryosections. Epithelial cells of PII are characterized by high and dense brush border at the apical side, elaborate folding of the lateral cell membrane and large basal extracellular labyrinth confined by a system of meandering cell extensions. Basal cytoplasmic zone, apical cytoplasmic zone, nuclei, mitochondria and apical small vacuoles were accessible for X-ray microanalysis. Concentrations of Na, Mg, P, S, Cl and K were different in the cytoplasmic zones along the basal-apical axis of the cell and in the organelles. PII cells lacked an apical tubulovesicular apparatus, instead they displayed an apical zone of smooth clear vesicles and small apical vacuoles. After freeze-drying, the small apical vacuoles and the smooth clear vesicles contained flocculent mass-dense material. Small apical vacuoles showed high concentrations of Mg (229 mmol/kg water), Na (132 mmol/kg water) and Cl (148 mmol/kg water). Sequestration of Mg in vesicles and small apical vacuoles and subsequent exocytosis between the microvilli of the brush border are supposed to be important steps in the transepithelial transport (tubular secretion) of magnesium by PII cells of marine fish.

Animals↗

PubMed1994

[Induction of differentiation of human gastric cancer cell line by retinoic acid].

The growth rate and weight of transplanted tumor of SGC7901 gastric cancer cell line, treated with 10 mumol/L retinoic acid (RA) in nude mice, were significantly reduced in comparison with those of control cells. The morphology of RA-treated cells was changed from ellipse shape with meandering margin of a large nucleus to shuttle shape with smooth margin of a small nucleus. With flow cytometry, it was found that G/O Phase markedly increased after the RA treatment, whereas S and G2 + M phase decreased. Especially the S phase fraction was lower than that of control cells. The above results indicated that RA could reverse biological and morphological phenotypes of the human gastric cancer cells in vitro and could induce differentiation of gastric cancer cells to a certain extent.

Animals↗

PubMed1993

[Postoperative follow-up after goniotrepanation with fornix-based conjunctival flap].

Goniotrephination with a fornix-based conjunctival flap was performed in 60 glaucomatous eyes. The postoperative course was monitored with special reference to intraocular pressure, anterior chamber depth, choroidal detachment and external fistulation. Some degree of choroidal detachment was observed in 1/3 of cases, extending centrally to the equator in only 11% and centrally to the vessel arcade in none. The anterior chamber was found to have become shallow in 16%, but this persisted longer than 3 days in only 6.7%. In 13.3% a external fistula arising from the conjunctival wound persisted for more than 1 day. The described technique with a fornix-based conjunctival flap and meander-like suture at the limbus further reduces the frequency and severity of complications in filtering surgery.

Choroid↗