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At least 19 recordsLinked to original sources
PubMed1977

Malignant histiocytosis with chronic course. Ultrastructural and ultrastructural cytochemical studies.

Four cases of malignant histiocytosis with leukemic manifestations and chronic course were reported. Light microscopic, ultrastructural and ultrastructural cytochemical details of these atypical cells were demonstrated. Ultrastructurally these cells resembled hairy cells most closely among the known varieties of leukemic cells. However, ribosome-lamella complexes were not found and some atypical cells had a few short cytoplasmic projections. In addition, tartrate-resistant acid phosphatase was absent from these cells. We speculate that this leukemic reticuloendotheliosis with a chronic course seen in Japan seems to be analogous to malignant histiocytosis with massive splenomegaly reported by Vardiman et al.

Acid Phosphatase↗
PubMed1976

Studies on the ultrastructure, histochemistry and cytochemistry of the uninfected digestive gland of Bithynia tentaculata (Mollusca: Gastropoda) and on the ultrastructure of this host organ in snails infected with larval digeneans.

The structure and function of the digestive gland of the gastropod mollusc, Bithynia tentaculata, was investigated using ultrastructural, histochemical, and cytochemical techniques. The digestive gland was shown to be composed of two main cell types, the "digestive" cells and "secretory" cells. The digestive cells appeared to be concerned with the absorption and digestion of nutrients, while secretory cells produced digestive enzymes and calcareous concretions. Undifferentiated cells were scattered between these two main cell types. The pathological effects of larval digeneans on the digestive gland were also investigated, at the ultrastructural level. In such infected snails the digestive gland appeared to be degenerating. The significance of this tissue destruction was briefly discussed.

Acid Phosphatase↗
PubMed1976

Biogenesis of mitochondrial membranes in Neurospora crassa during cellular differentiation: ultrastructural changes accompanying differentiation.

The ultrastructural characteristics of Neurospora cells during dedifferentiation and redifferentiation of conidiospores into vegetative cells have been determined. This germination process occurs between 2 and 5 h after inoculation; by 3-5 h, approximately 50% of the cells have germinated. The cells enter the exponential phase of dry-weight gain between 4 and 5 h after inoculation. Several unusual structures are observed in Neurospora cells during germination. Whorled structures are frequently seen in the cytoplasm during germination, and occasionally at other times. They appear to be derived from the cytoplasmic membrane. Whorled structures of different appearance were observed in the mitochondria between 2 and 4 h after inoculation. Their number was related to the level of metabolizable carbohydrate, and was higher in 15% glucose-than in 2% sucrose-supplemented medium, and very low in medium containing 15% mannitol, or 2% sucrose+13% 2-deoxyglucose, or no added carbohydrate. The mitochondrial inclusions were osmiophilic and could be removed by treatment with 90% aqueous acetone in the cold, indicating that they were composed at least in part of lipid. The strong dependence of the number of mitochondrial inclusions on time and on carbohydrate supplementation, suggests that there is a physiological basis for these structures and that they reflect changes occurring in the mitochondria at times significant to cellular differentiation.

Carbohydrate Metabolism↗
PubMed1976

Herpes gestationis. Ultrastructure and ultrastructural localization of in vivo-bound complement.

Ultrastructural localization of C3 deposition in the skin of two patients with herpes gestationis was determined by using a peroxidase-antiperoxidase multistep technique. The tissue preparations can be stored for long periods of time and identical sections may be used for light and electron microscopic examination. The reaction products were seen throughout the entire lamina lucida and the basal cell plasma membrane appeared to be accentuated. The most remarkable ultrastructural changes in normal-appearing skin were the destruction of the basal cell membranes on the dermal side, localized cytoplasmic dissolution, and intracellular edema unaccompanied by inflammatory cells. Early, nonvesicular lesions showed basal cell degeneration and dermal inflammatory cells. Necrosis and loss of basal cells occurred in the next stage which resulted in microvesicles in which collagen or a well-preserved basal lamina formed the vesicle base. In the later blister stage, the basal lamina was usually lost. It is suggested that damage of basal cell membranes on their dermal side leads to the destruction of basal cells with the subsequent protrusion of epidermal and junctional substances into the dermis. This may result in inflammatory cell infiltration and blister formation.

Complement C3↗
PubMed1978

Ultrastructural and physiological studies on the longitudinal body wall muscle of Dolabella auricularia. I. Mechanical response and ultrastructure.

The physiological properties of mechanical response and the ultrastructure in the longitudinal body wall muscle (LBWM) of the opisthobranch mollusc Dolabella auricularia were studied to obtain information about excitation-contraction coupling in somatic smooth muscles responsible for smooth and slow body movement of molluscans. The contracture tension produced by 400 mM K was not affected by Mn ions (5--10 mM) and low pH (up to 4.0), but was reduced by procaine (2 mM). The K-contracture tension was not readily eliminated in a Ca-free solution containing ethylene glycol-bis(beta-aminoethyl ether)N,N,N',N'-tetraacetate (EGTA). A large contracture tension was also produced by rapid cooling of the surrounding fluid from 20 degrees to 5 degrees--3 degrees C even when the preparation showed no mechanical response to 400 mM K after prolonged (more than 2 h) soaking in the Ca-free solution. These results indicate that the LBWM fibers contain a large amount of intracellularly stored Ca which can be effectively released by membrane depolarization. The fibers were connected with each other, forming the gap junctions, the desmosomes, and the intermediate junctions. The sarcoplasmic reticulum (SR) consisted of vesicular and tubular elements, and was mostly located near the fiber surface. The plasma membrane showed marked tubular invaginations of 600-800 A in diameter, with many branches (surface tubules), extending inwards for approximately 2 micron. These surface tubules were closely apposed to the SR, and the bridgelike structures analogous to those in the triadic junction of vertebrate skeletal muscle were observed in the space between the surface tubules and the SR. It is suggested that the influence of membrane depolarization is transmitted inwards along the surface tubules to cause the release of Ca from the SR.

Acetylcholine↗
PubMed1977

Changes in ultrastructure and function of the sheep pigment epithelium and retina induced by sodium iodate. I. The ultrastructure of the normal pigment epithelium of the sheep.

The normal ultrastructure of the sheep pigment epithelial cells is described as a basis for the interpretation of toxic (sodium iodate) effects on these cells dealt with in two following papers. The morphological features of the different cell membranes and cell organelles, particularly the phagosomes and the lipid droplets, are discussed in relation to renewal of the photoreceptor outer segment, pigment epithelial and retinal metabolism, barrier mechanisms and electrical properties.

Animals↗
PubMed1979

Degeneration and regeneration of some mechanoreceptors. An ultrastructural study. III. Ultrastructure of reinnervated Herbst corpuscles.

The ultrastructure of reinnervated Herbst corpuscles shows that the regenerating nerve branches appear in the inner zone of the receptors at the end of the first month after nerve crush. The nerve branches are accompanied by the Schwann receptor cells. Two periods of regeneration can be established. During the first period the changes reflect mainly the quantitative relations between the regenerating nerve branches and the Schwann receptor cells, whereas during the second period the intracytoplasmic and intraaxoplasmic renewal of the organelles take place. The final regeneration of the receptors finishes at the end of the fifth month after nerve crush and one month later after nerve transection. Also, after transection the number of reinnervated receptors is less encountered.

Animals↗
PubMed1979

Degeneration and regeneration of some mechanoreceptors. An ultrastructural study. I. Ultrastructure of denervated Herbst corpusles.

The degenerative changes in the HERBST corpusles have been investigated at ultrastructural level during the 3rd h to 1 year after nerve section. The earliest changes have been established in the nerve ending followed by the remaining nonmyelinated and myelinated portion of the receptor nerve fibre. The changes reflect the retrograde character of the degenerative process. The receptor cell elements pass through the stage of activation followed by their destruction and elimination. The Schwann receptor cells fullfill the pagocytotic role in the elimination of the axonal debris, after that they have been also completely eliminated. Their places are occupied by the activated fibroblasts and developed collagen fibrils. One part of the perineural cells persist a long time after denervation and they preserve the common although modified receptor configuration.

Animals↗
PubMed1979

Degeneration and regeneration of some mechanoreceptors. An ultrastructural study. II. Ultrastructure of denervated Grandry corpuscles.

The ultrastructure of denervated Grandry corpuscles reveals the retrograde character of degenerative changes in the receptor nerve fibre. The denervation affects also the specific cell elements: the Schwann receptor cells and specialized cells. The both cell types pass through the phase of activation followed by degeneration and elimination. The process is significantly prolonged by the specialized cells. The Schwann receptor cells appear more dynamic and sensitive elements in the process of degeneration. After the full elimination of the specialized cells the denervated receptors cannot be established.

Animals↗
PubMed1975

[Ultrastructural changes in human skeletal muscles following tendon and nerve injuries. I. Ultrastructural changes following tendon injuries].

During reconstructive procedures performed 4-16 weeks after the tendon lesion the specimens obtained from the injured muscle have been examined by the authors. It was found that after the tendon injury inactivity atrophy develops and a condition of equilibrium could be observed at this time. The most important changes in the fine structure were seen in the contractile elements: these were atrophied, homogenized, fragmentated and ragged independently from the functional unities. The number of the mitochondria was considerably decreased, the sarcoplasmic reticulum was increased, and the difference between the originally red and white muscular fibres was indistinct. The glycogen content of the musculature was decreased, or it disappeared completely. No pathologic changes have been observed in the sarcolemma, the cell nuclei and the motor nerve end-organs.

Adult↗
PubMed1979

Influence of lead poisoning and ultrastructural changes in the body wall of Eisenia foetida (Savigny), Oligochaeta. I. Short action of different concentrations of lead and ultrastructural changes in the cells of the body wall.

The effect of short term influence of different concentrations of Pb(NO3)2 in the soil on the accumulation and localization of lead in the body wall cells of the earthworm Eisenia foetida (Savigny), Oligocheta, was studied histochemically. The experimental animals displayed the presence of lead deposits in the cytoplasm and vacuols of the epithelial gland cells which also showed morphological changes indicative of their increased secretory activity. Furthermore, a considerable accumulation of lead was found in the sarcoplasm and particularly in the sarcoplasmic reticulum of the muscle cells in the body wall. The histochemical data show that the most intense accumulation of lead is found in animals kept in an environment containing 0-05 mg Pb per 1 g of the soil. At this concentration of lead noteworthy morphological changes together with deposits of this metal are found in the mitochondria. This mitochondrial changes occurred together with the above mentioned, lead induced cytological deviations. They did not appear in other groups of experimental animals.

Animals↗
PubMed1979

Degeneration and regeneration of some mechanoreceptors. An ultrastructural study. IV. Ultrastructure of reinnervated Pacinian corpuscles.

The first signs of reinnervation of the Pacinian corpuscles have been established at the middle of the second month after nerve crush. The regenerative process pass through two periods. During the first period the progressive increase of the Schwann receptor cells has been observed parallel to the reduction of the regenerating nerve branches. During the second period the reorganization and renewal of the regenerated organelles takes place. Some organelles as dense core vesicles, coated vesicles and microtubules of the receptor nerve fibre show noticeable dynamics. The regeneration has been established only in the preexisting after denervation capsulated remnants of the receptors. After nerve transection the regeneration is prolonged one month later and the less of quantity reinnervated receptors have been observed.

Animals↗
PubMed1975

Ultrastructure of the contractile system of striated skeletal muscle and the processes of muscular contraction. I. Ultrastructure of the myofibril and source of energy.

1) The contractile system consists of thick and thin filaments arranged side by side in a double network of hexagonal cross-section. 2) The thick filaments are principally made up of myosin and the thin ones of actin, tropomyosin and troponin. 3) Myosin is an enzyme catalysing the hydrolysis of ATP; actin increases the specific activity of this enzyme, converting it from a Ca+2 sensitive ATPase to a Mg+2 sensitive ATPase. 4) Hydrolysis of the last phosphoryl group of adenosine triphosphate (ATP) salts is the energy source for muscle contraction. 5) The adenosine diphosphate (ADP) salts, formed by ATP splitting, are rephosphorylated and reinjected into the myofibril.

Actins↗