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Results for “Microscopy, Phase-Contrast”

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At least 469 records · Page 26Linked to original sources
PubMed1976

[Results of television microscopy utilization in spermatology].

The use of television microscopy in insemination laboratories was tested by VEB Studio-technik on two insemination stations of the GDR. A transistorised remote-observation system is described as a tool providing a universal range of applications for long-time no-maintenance operation of selected microscopes. The system was found to add to the accuracy and objective value of optical microscopy for spermatological studies. TV microscopy also will improve job conditions for the personnel involved.

Animals↗
PubMed1976

Antibody-coated bacteria in the urine of preschool and school-aged girls with asymptomatic bacteriuria.

Urine samples from 3564 girls aged 2 to 13 years were screened for evidence of infection. Cultures were positive (bacteria count, more than 10(5)/ml) in 61 (1.7%) by the dipslide method and in 55 (1.5%) by standard culture techniques. In 13 (23.6%) of the 55, antibody-coated bacteria (ACB) were detected in the urine. The clinical, bacteriologic, radiologic and urinalysis findings in children with ACB were no different from those in children in whom the bacteria were not coated. Direct examination of uncentrifuged urine under high power revealed one or more bacteria per two high-power fields in 96% of infected urine samples and in only 7% of noninfected samples. Five or more leukocytes per high-power field in centrifuged urine were detected in 36.7% of infected urine samples but not in noninfected samples. The ACB test did not differentiate between asymptomatic bacteriuria with parenchymal scarring or vesicoureteral reflux or both and asymptomatic bacteriuria without these abnormalities.

Adolescent↗
PubMed1976

Lymphocyte locomotion. I. The initiation, velocity, pattern, and path of locomotion in vitro.

The locomotive behaviour of human lymphocytes in coverslip preparations of clotted autoplasma was studied at +37 degrees C. Lymphocytes isolated from peripheral blood or from the tonsils did not move prior to membrane activation by means of incubation with phytohemagglutinin (PHA). After PHA stimulation the locomotion of 19 lymphocytes was analysed by time-lapse fliming. The locomotion was random, as evidenced by a median locomotive index of 0.64 (Q1-Q3 0.04-0.75) and comparatively slow, median velocity 15 mum/min (Q1-Q3 12-18). The locomotion of 5 other lymphocytes was studied at high magnification. It is suggested that the characteristic polarity of wandering lymphocytes, indicating the direction of movement, can be utilized in the analysis of the lymphocyte traffic in tissue sections of post-capillary high-endothelium venules.

Cell Movement↗
PubMed1976

Lymphocyte locomotion. II. The lymphocyte traffic over the post-capillary venules analysed by phase contrast microscopy of thin sections of rat lymph nodes.

Thin sections of lymph nodes from 14 rats were examined by phase contrast microscopy as regards direction of lymphoctes with amoeboid movement configuration (AMC) relative to the basement membrane of post-capillary high-endothelium venules (HE-cenules). Out of 118 lymphocytes with AMC, 82 appeared to be on theyr way into the venule from the lymph node parenchyma. This observation suggests that the lymphocyte traffic over the HE-venules is bi-directional, with the main migratory stream of lymphocytes from the lymph node parenchyma into the post-capillary venules.

Animals↗
PubMed1976

[Isolation and function of platelets. I. Platelet rich plasma. Comparison between 2 methods: gel filtration and albumin density gradient centrifugation. II. A new method using total blood: metrizamide gradient centrifugation].

Human platelets separated from platelet rich plasma (PRP) by two different methods: gel filtraton and centrifugation on albumin gradient have been compared for yield, cellular and protein contamination, ultra-structure, platelet populations, shape change, aggregability and functional preservation. A new method for the separation of platelets from total blood on metrizamide gradients has been established. This technique is rapid and easy; it avoids the initial centrifugation of the PRP where about 30% of the platelets are lost and needs of blood 5 to 10 ml of blood.

Blood Platelets↗
PubMed1976

[Cytological studies in pulmonary pathology].

Cytological investigations of the bronchial secretion and sputum in particular have acquired in recent years a great practical significance in pulmonary pathology. It is recommended to use cytodiagnosis along with prophylactic X-ray examinations of the population to detect pulmonary pathology, in particular among individuals with a higher risk of developing cancer. A substantiated opinion is put forward that cytodiagnosis should precede examinations of patients with clinico-roentgenologically confirmed changes in the lungs.

Adenoma↗
PubMed1976

[Refringence phenomenon as a sign of the degree of differentiation of immunocompetent cells].

Quantitative and qualitative analyses of the refringence phenomen in immunocompetent cells of various organs of rabbits and CBA line mice under conditions of immunological activity, as well as in those of children with ataxia-teleangiectasia, showed that immunoblasts contained predominantly non-refringent nuclei, mature plasmatic cells--mainly highly refringent nuclei, and young plasmatic cells occupied a position in the middle of the two. These data, as well as the absence of the refringence phenomenon in the cells of lymphosarcoma in man corroborate a direct relationship between the phenomenon and the process of differentiation of cells.

Animals↗
PubMed1976

Electron microscopic observations on the interaction of the myosin head subunit with actin in myofibrils.

Glycerol-extracted rabbit psoas muscle fibres were treated with a solution containing the head subunits of myosin. Interaction of the isolated myosin heads with actin filaments in situ was indicated by an increase in the density of the I-band and by an increased diameter of actin filaments alongside their whole length. We conclude that actin filaments are able to interact with a considerably larger number of myosin molecules than that available in the myofibril under in vivo conditions.

Actins↗
PubMed1976

[Ultrastructure of the proximal neurosecretory contact region in a sturgeon].

The proximal neurosecretory contact region (PCR), a homologue of the tetrapoda median eminence occupies the rostral and chiefly the ventral surfaces of the hypothalamic tuber cinereum. Three types of granule-containing neurosecretory fibres and their terminals have been found in the PCR with the electron microscope. Peptidergic, A1 and A2 type fibres contain granules of 120--300 nm and 100--170 nm in diameter, correspondingly, and monoaminergic B fibres have granules of 80--100 nm in diameter. Neurosecretory terminals and tanycyte vascular "endfeet" make contacts with a 70 nm thick outer basement membrane of the primary portal capillaries. Some thin horizontally oriented tanycyte branches form a multiserial layer bordering the external zone of the PCR from the preoptico-hypophyseal tract. Few neuroglial cells with pale cytoplasm and numerous lysosomes and lipofuscin granules are seen there. It is hypothesized that, like in other vertebrates, in the PCR of Acipenseridae both peptide and monoamine hypophysiotropic neurohormones may be discharged in the portal circulation to affect the functional activity of glandular cells of the pars distalis.

Animals↗
PubMed1975

[Realization of systemic relations in the behavior of early neuroblasts in nerve tissue cultures].

When cultivating the nervous tissue of newborn rats, rabbit embryos and tadpoles (as whole fragments or dissociated cells), 3 groups of neuroblasts are distinguished: differentiating, migrating and with growing processes. These groups correspond to different stages of neuroblast development in vivo and their presence in the tissue cultures of different brain regions reflects the heterochrony of cell development in these regions. The neuroblasts realize their morphogenetic potential within several days of cultivation irrespective of the contact with the other cells but the subsequent differentiation (dendrite branching, nuclear clearance etc.) proceeds only in cells united in aggregates.

Animals↗
PubMed1978

[Morphological virus diagnosis--electron microscopy study of animal viruses with negative contrast procedure].

Reported in this paper are results obtained in morphological virus diagnosis by using the negative contrast technique on the basis of electron microscopy. The availability of high-efficiency electron microscopy as well as of perfectly improved techniques of preparation, knowledge of the latest virus model concepts, and indivudual skills in diagnosis are essential conditions for the above approach. Parvoviridae, picornaviridae, and togaviridae are identifiable only in high particle concentrations and by group representation. Papovaviridae, adenoviridae, herpetoviridae, poxviridae, and reoviridae, on the other hand, can be safely identified even as single particles. The diagnosis of orthomyxoviridae, paramyxoviridae, rhabdoviridae, and retroviridae is facilitated by their own dimensions and their characteristic helico-symmmetrical nucleocapside. Coronaviridae are of highly conspicuous morphology but, nevertheless, pose problems in differential diagnosis. Substantive improvement of morphological virus diagnosis, in terms of minute details, may be achieved by means of the negative contrast method on the basis of immune electron microscopy. Advantages implied in that morphological method include less time-consuming and quite uninvolved practicability and good dependability of diagnosis for more efficient decision-making in research and practice.

Animals↗