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At least 541 records · Page 30Linked to original sources
PubMed1985

Killed Listeria-induced suppressor T cells involved in suppression of delayed-type hypersensitivity and protection against Listeria infection.

Pretreatment of mice by intravenous injection with killed Listeria provided neither delayed-type hypersensitivity to Listeria protoplasm nor protection against Listeria infection. Assuming that this suppression is due to suppressor cells, we attempted to clarify their induction and characterization. Pretreatment with killed BCG instead of killed Listeria suppressed the induction of DTH and protection in subsequent Listeria-immunized mice. Conversely, pretreatment with killed Listeria suppressed subsequent induction of DTH to PPD or protection from tuberculosis. Thus, these suppressions were induced antigen nonspecifically. Transfer of splenic non-adherent cells from killed Listeria-injected mice which had been treated with anti-BA theta serum plus complement, or had been passed through Sephadex G-10 columns, resulted in both afferent and efferent DTH suppression, suggesting that the DTH suppression is closely associated with suppressor T cells. Moreover, the splenic nonadherent cells from killed Listeria-injected mice showed suppression in vitro of listericidal activity of PEC from Listeria-immune mice in the presence of Listeria protoplasm.

Animals↗
PubMed1989

[Ultrastructural observation on the body wall of Pagumogonimus skrjabini].

This paper deals with the ultrastructure of the body wall of adult Pagumogonimus skrjabini by transmission electron microscopy. Infected crabs were collected from Siyen, Hubei Province, and adult worms were obtained from the lungs of experimentally infected dogs 90 days post-infection. The normal structure of body wall of the P. skrjabini is composed of tegument, tegument cell, muscle muscle cell and protoplasmic tubules, all of which form together syncytium. The tegument contains external plasma membrane, tegument matrix and basal plasma membrane. The cell coat in fine granules is distributed over the whole external plasma membrane surface. The tegument matrix contains various secretory bodies, vesicles and mitochondria. The tegument cell is irregular in shape. Golgi complex, ribosome, autolysosome are seen in the cytoplasm. There are two layers of muscle, the external circular muscle and the inner longitudinal muscle layers. The nucleus of immature muscle cell has many heterochromatins, while the nucleus of mature muscle cell is large and round in shape. Mitochondria and glycogen granules are transmitted from muscle cell proper to the muscle by protoplasmic tubules (Figs. 1 approximately 7).

Animals↗
PubMed1989

[Ultrastructural study of the action of concentrated solutions of chlorhexidine digluconate on cocci in salivary flora in vitro].

Chlorhexidine digluconate is a potent antibacterial compound widely used in stomatology. In this work the authors studied the ultrastructural alterations of cocci in salivary flora, treated "in vitro" with high concentrations of chlorhexidine digluconate (0.5%, 1% and 2%). The effect of chlorhexidine 0.5% on the cocci revealed rarefaction of the cytoplasm, ruptures of the cellular wall and alterations of the protoplasm in the form of "plasmoptysis" and "plasmolysis". Treatment of the cocci with higher concentrations (1% and 2%) of the drug caused a change in the appearance of the protoplasm, showing a general coagulation, damage of the cytoplasmic membrane and the cellular wall, malformation of the cell and disorganization of the nuclear chromatin. The ultrastructural alterations observed are in agreement with the results of preliminary biochemical studies.

Adolescent↗
PubMed1985

[The neurocytes of the caudal part of the tuberomamillary nucleus in Ovis aries L. (light microscopy and electron microscopy studies)].

The neurons of the pars caudalis nuclei tuberomammillaris (pc-NTM) were studed light-microscopically and electron-microscopically in sheep and rams of Merino breed. In our study we observed: In the regarded neural nucleus, there is the majority of the great neurons (up to 60 microns in diameter) rich in the NISSL's bodies. When stained with the cresyl violet, the NISSL's substance is apparently stored mainly in peripheral area of the cell body and in the distant parts of numerous protoplasmic processes, what evokes an impression of the "jagged" surface of these cells. After staining with paraldehyde fuchsin, we found purple coloured lumps of irregular shape stored outside the cell bodies, in the neuropil. The less extended cells, usually with lower content of NISSL bodies, are in pc-NTM less frequent. In the electron-microscopic study we identified 3 types of neurons: Cells rich in rough endoplasmic reticulum; "light" cells, "dark" cells. The cells of the 1st type were the most frequent ones. Cisterns of rough endoplasmic reticulum in the 1st type of cells are often dilated. The protoplasmic processes of these cells are frequently stepped over by flat tubuli of endoplasmic reticulum. The 2nd type of cells is characterized by the light cytoplasmic matrix, low quantity of endoplasmic reticulum and frequent occurrence of lipofuscin bodies. The 3rd type of cells are characterized by the high density of cytoplasmic matrix, well developed GOLGI complex, and very broad cisterns of endoplasmic reticulum, forming a labyrinth, and it is bound to a broad perinuclear space.

Animals↗
PubMed1979

The effect of Toxoplasma cell fractions and mycobacterial immunostimulants against virulent Toxoplasma gondii in mice.

Toxoplasma gondii tachyzoites were disrupted in a Ribi cell fractionator and separated into cell walls and protoplasm by differential centrifugation. These products were used alone or combined with a mycobacterial glycolipid (P3) and injected either as oil-in-water emulsions or incorporated in Freund's incomplete adjuvant. Mice were vaccinated by intravenous or intradermal routes and challenged intraperitoneally with a highly virulent strain of Toxoplasma gondii. A local granuloma formation was induced after i.d. inoculation of Toxoplasma vaccines containing P3 as this glycolipid enabled an adherence of the antigens on the mineral oil droplets. The adjuvant effect of P3 on antibody formation was also observed. Most of the fractions showed a low, but statistically significant prolongation of survival time. Vaccination by the i.v. route with homologous or heterologous antigens, including Trypanosoma cruzi, were not significantly effective, with the exception of a high dose of Toxoplasma protoplasm associated with P3.

Adjuvants, Immunologic↗
PubMed1976

Evaluation of bovine spermatozoal morphologic features after staining or fixation.

Two experiments were conducted to evaluate effects of 3 stains and 2 fixatives on morphologic features of bovine spermatozoa. In experiment 1, the morphologic features of acrosomes of raw and incubated, extended spermatozoa were evaluated after staining with Hancock's Blom's or Wells-Awa's stains or after fixation with buffered glutaraldehyde. Evaluations were done of stained smears by bright field microscopy and of fixed, unstained preparations, by differential interference contrast microscopy, using wet mounts. Raw semen samples from 1st ejaculates of 80 bulls were evaluated. The percentage of spermatozoa with intact acrosomes averaged 83.5% in unstained preparations fixed in glutaraldehyde, compared with averages of 68.1, 74.5, and 67.4% for smears stained with Hancock's, Blom's, or Wells-Awa's procedures (P less than 0.01). From these results, it appeared that procedures for preparing stained smears were detrimental to acrosomes. Although counts for other acrosomal abnormalities differed (P less than 0.01) in each treatment, patterns were inconsistent. With incubated, extended spermatozoa from 57 bulls, glutaraldehyde-fixed, unstained samples had more (55%) intact acrosomes (P less than 0.01) than did samples stained with Hancock's or Blom's procedures (24.0 and 34.7%, respectively, but the former were not significantly different from Wells-Awa-stained smears (49.3% intact acrosomes). In experiment 2, several morphologic characteristics of spermatozoa from 15 1st ejaculates of 7 bulls were evaluated after staining with Hancock's or Blom's stains or after fixation in buffered glutaraldehyde or buffered formal saline fixatives. Higher counts (P less than 0.01) of head abnormalities were found in wet, unstained fixed preparations (4.83, 4.47, 7.87, and 7.93% respectively, for Hancock's, Blom's, glutaraldehyde, and formol saline methods). There were more (P less than 0.05) separated heads on stained, dry smears (1.43, 1.23, 0.47, and 0.47%, respectively, for Hancock's, Blom's, glutaraldehyde, and formol saline procedures). Fixation with buffered glutaraldehyde resulted in higher counts (P less than 0.01) of proximal protoplasmic droplets (2.47, 1.03, 0.67, and 1.43%, respectively, for glutaraldehyde, Hancock's, Blom's, and formol saline procedures). Although not significant, the same trend was observed for distal protoplasmic droplets...

Acrosome↗
PubMed1980

[Quantitative histological observations in gliomas (author's transl)].

30 autopsy cases of gliomas (5 fusiform glioblastomas, 5 multiform glioblastomas, 5 fibrillary astrocytomas, 5 protoplasmic astrocytomas, 5 oligodendrogliomas, 5 spongioblastomas) were studied by means of morphometry. 7 parameters (volume and area parameters of tumor vessels and of tumor cell nuclei, mitoses) were tested for the ascertainament of useful quantitative criteria for the objective differentiation of the gliomas. 210 statistical comparisons were carried out. Significant differences were observed in 32 of them. It could be demonstrated that the parameters of the tumor cell nuclei are most useful in the differentiation of the gliomas. Significant differences do not exist between fusiform glioblastoma--multiform glioblastoma, fusiform glioblastoma--oligodendroglioma, fibrillary and protoplasmic astrocytoma--spongioblastoma.

Adult↗
PubMedDate not supplied

[Relationship between culture and conditions, the qualitative composition of a culture of Bacillus brevis and its formation of gramicidin C].

Qualitative composition of the population of Bacillus brevis was found to depend on growth conditions. Under optimum aeration conditions for growth of the culture and biosynthesis of gramicidin C, the population was polymorphous and contained cells and spores of different age. No spores and prospores were found in the culture in conditions of weak and strong aeration. The population consisted only of young, intensively coloured cells with homogeneous or weakly differentiated content in conditions of strong aeration. Cells with the differentiated protoplasm containing large, distinctly seen vacuoles were found in conditions of weak aeration. Gramicidin C was synthesized by young cells with basophilic homogeneous or weakly differentiated protoplasm.

Bacillus↗
PubMed1981

[Relationships between spermiological, biochemical, endocrinological and fertilizing characteristics of boar ejaculates].

Ejaculate volume, sperm concentration, total number of abnormal spermatozoa, number of spermatozoa with protoplasmic droplet, and the content of chlorides, magnesium, calcium and testosterone in semen plasma were evaluated in 155 ejaculates obtained from 77 boars. Further, the evaluation included the fertilizing ability of the ejaculates, expressed by conception rate after the first insemination, average number of all piglets and live-born piglets in litter after inseminations with the studied semen. The following significant (P less than 0.01) relationships were found after the evaluation of the mutual correlations of the studied characteristics: ejaculate volume to sperm concentration (r = -0.496), chlorides to calcium (r = -0.240), chlorides to magnesium (r = -0.492), magnesium to calcium (r = +0.261), testosterone to conception rate after the first insemination (r = -0.222), boar age to ejaculate volume (r = +0.285), boar age to sperm concentration (r = -0.375), boar age to magnesium (r = -0.281), length of sexual rest to total percentage of abnormal spermatozoa (r = +0.323) and to the percentage of spermatozoa with protoplasmic droplet (r = +0.367). The importance of these findings is treated in discussion.

Animals↗
PubMedDate not supplied

[Model of mechanical autooscillation in plasmodium of Myxomycetes].

A mathematical model of push-pull movement of linear protoplasm is proposed. The model is considered for a two-chamber system whose autooscillations are induced by an active force during contractions of the filaments. Estimations of the rate of protoplasm flowing, the time of quenching in the passive system, as well as the general course of time relationships of the rate and radial changes of the strand radius agree with the experimental data.

Mathematics↗
PubMedDate not supplied

Lobar pilocytic astrocytomas of the cerebral hemispheres: I. Diagnosis and nosology.

This study provides neuropathological and neuroradiological observations on 11 cases of lobar pilocytic astrocytomas of the cerebral hemispheres, reappraising potential diagnostic caveats. These tumors may show variable degrees of contrast enhancement on computed tomography, as well as gadolinium uptake on magnetic resonance imaging, making them indistinguishable from malignant gliomas. Histopathologically, although typically pilocytic, they may exhibit areas of increased cellular density with protoplasmic and multinucleated glial elements (pilo-protoplasmic astrocytoma). The presence and particularly the abundance of distinct gliodegenerative structures, i.e. eosinophilic granular bodies (EGBs) and to a lesser degree Rosenthal fibers, in conjunction with collateral clinical, histologic and imaging parameters may facilitate oncotypic diagnosis. Mixed pilocytic and fibrillary astrocytomas are recognized, while malignant change may also rarely occur in longstanding lobar pilocytic astrocytomas.

Adolescent↗
PubMed1994

Reaction of microglial cells in human astrocytomas (preliminary report).

Forty human primary brain tumors: twelve protoplasmic, six gemistocytic, four fibrillary and ten anaplastic astrocytomas, eight glioblastomas were submitted for immunohistochemical and histochemical characterization of microglia in tumor tissue and in its surroundings. The following antibodies were used: GFAP, ferritin, CD45RO and lectin RCA-1. It was found that the greatest number of ramified microglia occurred in gemistocytic astrocytomas. In the protoplasmic and fibrillary astrocytomas both the ramified and amoeboid microglia were observed. In glioblastomas and anaplastic astrocytomas the greatest number of amoeboid microglia and very rarely ramified microglial cells were found. It is suggested that differences between the various kinds of astrocytomas determine the difference in the type of microglia reaction. It is assumed that this might be caused by the differences in secreting some factors by these tumors astrocytes.

Antibodies↗
PubMed1997

D-serine as a neuromodulator: regional and developmental localizations in rat brain glia resemble NMDA receptors.

D-Serine is localized in mammalian brain to a discrete population of glial cells near NMDA receptors, suggesting that D-serine is an endogenous agonist of the receptor-associated glycine site. To explore this possibility, we have compared the immunohistochemical localizations of D-serine, glycine, and NMDA receptors in rat brain. In the telencephalon, D-serine is concentrated in protoplasmic astrocytes, which are abundant in neuropil in close vicinity to NMDA receptor 2A/B subunits. Ultrastructural examination of the CA1 region of hippocampus reveals D-serine in the cytosolic matrix of astrocytes that ensheath neurons and blood vessels, whereas NR2A/B is concentrated in dendritic spines. By contrast, glycine immunoreactivity in telencephalon is the lowest in brain. During postnatal week 2, D-serine levels in cerebellum are comparable to those in adult cerebral cortex but fall to undetectable levels by day 26. During week 2, we observe parallel ontogeny of D-serine in Bergmann glia and NR2A/B in Purkinje cells, suggesting a role for astrocytic D-serine in NMDA receptor-mediated synaptogenesis. D-Serine in the radial processes of Bergmann glia is also well positioned to regulate NMDA receptor-dependent granule cell migration. In the inner granule layer, D-serine is found transiently in protoplasmic astrocytes surrounding glomeruli, where it could regulate development of the mossy fiber/granule cell synapse. D-Serine seems to be the endogenous ligand of glycine sites in the telencephalon and developing cerebellum, whereas glycine predominates in the adult cerebellum, olfactory bulb, and hindbrain.

Animals↗
PubMed1996

The structure and function of blood-brain barrier in ischaemic brain stroke process.

The central nervous system both anatomically and functionally has a certain autonomy in comparison with the rest of the system thanks to the so called barriers dividing brain from both blood and cerebro-spinal fluid. Capillary vessels in brain are additionally surrounded by protoplasmic process of neuroglial cells. They are astrocytes which by means of protoplasmic process hermetically surround capillary vessels from the outside. Owing to that astrocytes create an additional layer, that has to be overcome by chemical compounds circulating in blood (2). Brain barrier fulfils an immunological function. It protects brain tissue against fluctuations in concentration of respective components occurring in blood plasma and against destructive blood components (2, 7). Lowering of brain flow of blood below 10-15 ml/100 g/min causes deficit of glucose and oxygen, indispensable for proper oxido-reductive processes. The most important factor determining brain tissue damage is a constant shortage of high energetic phosphate. Damage to mechanisms depending on energy causes ischaemic depolarisation phenomenon, after which potassium ions come out of cells and sodium and calcium ions come into them. Neurotransmitters, stimulating amino acids including, are being freed in a quantity that is conductive to toxic activity. Fall of blood flow causing acidosis provokes disturbances in vessel self-regulation, and lactates created are additional factor that damages tissues. Pathophysiological changes mentioned above lead to heavy injury and death of cells (3, 12). The intensifying acidosis and the process of maturing of morphological changes in ischaemic focus cause a rise in penetrability of blood-brain barrier (1, 2, 8). Works considering behaviour of blood-brain barrier in the process of brain stroke, are for the most part based on experimental models.

Aged↗
PubMed1962

Responses of cells to pH changes in the medium.

Studies were made with time-lapse motion pictures of the reactions of cells in culture to changes in their environment. The concentrations of H(+), HCO(3) (-)and CO(2) in the medium were altered in such a way that each, in turn, could be maintained constant while the others were varied. Observations were made on the shape of the cells, their activity, and their relation to the substratum. Characteristic reversible changes in the cells were observed whenever environmental pH was altered. Elevation of the pH accelerated cell movements and caused contraction of the cytoplasm, while lowering of the pH retarded and eventually stopped all cell activity, causing apparent gelation of the protoplasm. These responses did not occur when HCO(3) (-) and CO(2) were varied without changing the pH. It is suggested that local pH changes in the micro-environment of a cell's surface may be a significant factor in controlling cell behavior in culture and in vivo.

Bicarbonates↗
PubMed1963

KINETICS OF WATER LOSS FROM CELLS AT SUBZERO TEMPERATURES AND THE LIKELIHOOD OF INTRACELLULAR FREEZING.

The survival of various cells subjected to low temperature exposure is higher when they are cooled slowly. This increase is consistent with the view that slow cooling decreases the probability of intracellular freezing by permitting water to leave the cell rapidly enough to keep the protoplasm at its freezing point. The present study derives a quantitative relation between the amount of water in a cell and temperature. The relation is a differential equation involving cooling rate, surface-volume ratio, membrane permeability to water, and the temperature coefficient of the permeability constant. Numerical solutions to this equation give calculated water contents which permit predictions as to the likelihood of intracellular ice formation. Both the calculated water contents and the predictions on internal freezing are consistent with the experimental observations of several investigators.

Amoeba↗
PubMed1988

Sporothrix schenckii endophthalmitis in a patient with human immunodeficiency virus infection.

A 30-year-old homosexual man with a positive serologic test for human immunodeficiency virus and a history of successfully treated disseminated cutaneous sporotrichosis developed a granulomatous uveitis that worsened with topical and subconjunctival steroid therapy. Culture of the aqueous aspirate yielded Sporothrix schenckii. The patient was treated with intravenous amphotericin B and intravitreal amphotericin B, kanamycin sulfate, and amikacin sulfate. Subsequent aqueous and vitreous cultures were negative, but the intraocular inflammatory process progressed and ultimately led to enucleation of the eye. Histopathologic examination revealed granulomatous inflammation of the anterior uvea and scattered S schenckii in the anterior and posterior chambers. Electron microscopy demonstrated that most of the organisms had disorganized protoplasm. Although treatment failed to ameliorate the progressive intraocular inflammatory process, the negative cultures and the electron microscopic observations suggest that the treatment was reasonably effective in killing S schenckii within the eye. To our knowledge, this is the first case report of S schenckii endophthalmitis in a patient with human immunodeficiency virus infection.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Photoreceptor morphogenesis in the human retina: a scanning electron microscopic study.

There are a number of scanning electron microscopic (SEM) studies on retinal photoreceptors of vertebrates. However, most of these are concerned with the adult retina, and only a very few deal with developing photoreceptors. In man, SEM studies have not been carried out on photoreceptor morphogenesis during fetal or postnatal stages. Hence, the present study was undertaken to examine the sequential morphological changes in developing photoreceptors during different gestational ages in the human retina. Retinas of human fetuses of gestational ages of 10-25 weeks and from autopsy of a 5-month-old infant were processed for SEM. The observations show some new information on the morphogenesis of photoreceptors. At 10-11 weeks, the outer and inner neuroblastic zones are well developed and separated from each other by the layer of Chievitz. By 15-16 weeks, the photoreceptor precursors appear as spherical inner segments on the scleral surface of the outer neuroblastic zone. Cilia develop as small protrusions from the apical ends of the inner segments. Photoreceptor inner segments become arranged in mosaic pattern by 18-19 weeks. In the mosaic, large cone inner segments (putative blue cones) stand out prominently from the remaining small cone inner segments (prospective red/green cones). The rod inner segments are identifiable and show cilia. Between 19-20 and 24-25 weeks, the cone inner segments elongate and change in shape from spherical to oval. At 24-25 weeks, the outer segments develop from the distal ends of rod cilia. At this period, the inner segments of rods and cones are interconnected by protoplasmic projections. Although the precursors of both rods and cones appear to be in a similar state of development at 14-15 weeks gestation, the rods undergo morphological maturation earlier than do the cones. Photoreceptor development in the anterior retina lags behind that of the posterior retina by about 10 weeks. At 5 months after birth, the posterior retina possesses fully developed photoreceptors that are comparable to those of the adult. However, the photoreceptors in the ora serrata resemble those in the posterior retina of 24-25 weeks gestation.

Fetus↗