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Biomedical subjects

E Eerola

Publications and source records attributed to E Eerola.

103 records · Page 6Linked to original sources
PubMed1983

Immune capacity of the chicken bursectomized at 60 hours of incubation: mitogen-induced cell proliferation and immunoglobulin secretion.

Chickens were bursectomized surgically at 60 hr of incubation. Bone marrow cells from the bursectomized (Bx) and control (Co) chickens responded equally well by proliferation to B cell mitogens (dextran sulfate, anti-mu, anti-gamma) when studied at the age of 10 weeks. In contrast, spleen cells of Bx chickens responded significantly less to anti-mu and anti-gamma than did spleen cells of the Co chickens. When observed at the age of 10 days, a significantly depressed secretion of IgM, IgG, and IgA by the Bx cells was observed in vitro. This difference between the Bx and Co chickens had disappeared when studied at the age of 10 weeks.

Aging↗
PubMed1982

The effect of different antibody affinities on ELISA absorbance and titer.

Twenty-one rabbit serum samples were assayed for IgG antibodies against 3-iodo-5-nitrophenyl-epsilon-amino-n-caproic acid (NIP-cap) by equilibrium dialysis and enzyme-linked immunosorbent assay (ELISA). The results of ELISA, expressed either as absorbances or titers, did not correlate to antibody concentration or average affinity measured by the equilibrium dialysis. Affinity distributions of the antibodies within each sample were determined by equilibrium dialysis in 30 antigen concentrations. Thus, it was possible to study the correlation of ELISA results with separate ranges of antibody affinities. ELISA absorbances measured at a low sample dilution (1:80) correlated with high affinity antibodies (affinity greater than 8 X 10(-6) M-1). Use of high antigen density increased this correlation. End-point titers obtained at a low cut-off absorbance level tended to correlate to a larger range of affinities (affinity greater than 6 X 10(4) M-1). ELISA measures antibodies of different affinities depending on how the results are expressed. This can be utilized in qualitative characterization of the measured antibodies.

Animals↗
PubMed1982

Induction of B cell differentiation in vitro by bursal epithelium.

The inductive capacity of in vitro cultured epithelium of chicken bursa of Fabricius and of its soluble products on B cells precursors was evaluated. The appearance of surface Ia-like antigens was used as an indicator of the early B cell differentiation in vitro. Cultured bursal epithelium as well as soluble substances produced by it were able to initiate B cell development; Ia alloantigens were induced by both syngeneic and allogeneic epithelia. In both cases the induced Ia antigens represented the genotype of the responding cells.

Animals↗
PubMed1982

Osteolysis after rigid fixation. The possible role of periosteal neural mechanoreceptors in bone remodeling.

Rigid intramedullary fixation in the rat tibiofibular bone of a tibial fracture caused the development of nonunion in the associated fibular fracture, with marked osteolytic resorption of the fibular fragments. In contrast, with flexible fixation, the associated fibular fracture healed normally. The tibial fractures healed uneventfully in both cases. Histologic examinations showed that there exists a plexus of encapsulated nerve endings (Pacinian corpuscles) in the periosteum of the fibula, at the distal tibiofibular junction. The rat fibula forms a bony contact with the lower midshaft of the anteriorly curved tibia, acting as a supporting shaft. The periosteal neural mechanoreceptors probably sense the fibular loading when the tibia is bent during weight-bearing. Fibular resorption in rigid fixation could be attributed to the rigid intramedullary nail preventing tibial bending and loading of the receptor area. In other words the neural elements could detect the stress protection due to rigid fixation and coordinate the adverse remodeling process.

Animals↗
PubMed1981

Thymic morphology during in vitro culture.

Morphology of guinea-pig thymic fragments was studied sequentially during in vitro organ culture by using light and electron microscopy and 3H-thymidine autoradiography. In culture the fragments became alymphoid. Thymic lymphocytes started to disappear first at the corticomedullary border, which gradually broadened, giving rise to the alymphoid epithelial fragments. As the lymphoid cells disappeared the thymic epithelium began to transform into a keratinized squamous epithelium. The keratinization started in the cells surrounding the Hassall's corpuscles, causing the enlargement of the corpuscles and finally total keratinization of the cultured epithelial fragments. In autoradiographic studies cell proliferation could be observed in uncultured thymuses at the cortical pericapsular area. In cultured alymphoid fragments labelled cells were distributed diffusely in the epithelium. Later labelling was concentrated to epithelial cells transforming to keratinized epithelium. Ultrastructural studies similarly showed transformation of the epithelial cells to squamous keratinized epithelium. The observation support the view that Hassall's corpuscles are derived from the keratinized thymic epithelium and that their existence is connected to the normal function of the epithelium.

Animals↗
PubMedDate not supplied

Flow cytometric DNA analysis of defined stages of rat seminiferous epithelial cycle during in vitro differentiation.

The stages of the rat seminiferous epithelial cycle have been isolated for flow cytometric analysis of DNA and for culture, using transillumination-assisted microdissection. Precise stages have been identified by phase contrast microscopy of live cell squashes from adjacent segments. Each stage of the cycle showed a characteristic flow cytometric pattern with haploid (1C), diploid (2C) and tetraploid (4C) peaks. Stages I to VIII of the cycle showed an additional hypofluorescent (0.25-0.70C) peak due to a reduced dye-binding capacity of maturation phase-spermatids at steps 15 through 19. The appearance of the hypofluorescent haploid peak coincided with the second nucleoprotein transition at step 15 of spermiogenesis and the homogeneous condensation of the chromatin seen in electron microscopy. As a concomitant of the formation of disulphide bonds during epididymal maturation, the fluorescence intensity decreased further to reach a relative value of 0.07C in the cauda epididymidis. The constant 1C peak was raised by round and elongating spermatids (steps 1-14), 2C by spermatogonia, secondary spermatocytes and Sertoli cells, and the 4C peak by primary spermatocytes and spermatogonia at G2 or M phase of the mitotic cycle. The proportion of each peak accurately reflected the relative proportion of cells in most stages of the cycle when compared with morphometric measurements of histologic preparations. DNA flow cytometry is a suitable method for quantitative evaluation of cultured seminiferous tubule segment DNA. Although the relative yield of the meiotic reductive divisions in vitro is comparable with that observed in vivo, steps 9 and 15 of spermiogenesis involving nucleoprotein transitions and spermiation itself did not occur under the present culture conditions.

Animals↗
PubMedDate not supplied

Mutagen effects on rat seminiferous tubules in vitro: induction of meiotic micronuclei by adriamycin.

Mutagen effect on male germ cells can be analyzed by micronucleus induction during meiotic divisions. These can be followed in vitro by culturing seminiferous tubular segments from stages of the epithelial cycle that contain late pachytene and diakinetic primary spermatocytes. We studied the formation of micronuclei in this test system using adriamycin as a model mutagen. Micronuclei were induced in a dose-dependent manner at concentrations of 1-10 ng/ml that were far below the dose that caused morphologically or biochemically detectable cytotoxic effects. The meiotic micronucleus induction in vitro is a potentially sensitive test system of male germ cell mutagenesis.

Animals↗
PubMedDate not supplied

Effect of sex chromosome aneuploidy on growth of human skin fibroblasts in cell culture.

Growth of human skin fibroblast lines with sex chromosome aneuploidy was studied in cell culture. Two lines were derived from individuals with 45,X and two from individuals with 47,XYY chromosome constitution. The aneuploid cell lines were compared with normal skin fibroblasts derived from age-matched same-sex siblings. To ensure similar conditions in culture, each study-control pair was treated simultaneously and equally in all steps. Growth in both 45,X cell cultures slowed down earlier than in control cultures. One of the 47,XYY cultures grew faster and the other at a similar speed to the control culture. Thus, the 45,X cell lines seemed to have lesser, and one of the 47,XYY cell lines greater, growth potential than the 46,XX and 46,XY cells, respectively. These differences in the final cell numbers may relate to changes in the rate of cell division of the aneuploid cell lines. However, the results do not support the hypothesis that an increasing number of sex chromosomes decreases the rate of cell division.

Adolescent↗
PubMedDate not supplied

Healing of experimental fractures in the denervated limbs of the rat.

The effects of denervation on healing of experimental fractures of the tibia after sciatic nerve section or spinal cord transsection or both were studied in rats. In addition to normal weight-bearing controls, non-weight-bearing controls were prepared by means of experimental hip luxations. The healing of fractures was monitored by tensile strength measurements, and by X-ray studies up to two months. The tensile strengths of the fractures with peripheral nerve lesion or with spinal cord trauma were significantly higher than those of the respective weight-bearing or non-weight-bearing control fractures at the early phase of healing. Osseous union of denervated fractures was radiographically evident earlier or at least at the same time as in the controls. Denervation, however, caused irregularities in the radiopacity and increased the length of fracture callus. These results confirm the clinical observations on enhanced healing of fractures in extremities of patients with spinal cord trauma.

Animals↗
PubMedDate not supplied

Relatedness of Pseudallescheria, Scedosporium and Graphium pro parte based on SSU rDNA sequences.

Genetic relatedness of 10 strains of opportunistic human pathogenic fungi in the genera Pseudallescheria and Scedosporium and related fungi including Petriella setifera, Graphium tectonae and Ceratocystis fimbriata, were tested by sequencing the entire SSU rDNA. From these molecular data, the imperfect genus Scedosporium can be divided in two, S. prolificans being separable from the S. apiospermum complex. Nearest sexual relatives of S. prolificans seem to be in the microascalean genus Petriella. Strains of Ps. boydii and S. apiospermum, although differing by their previously known DNA/DNA reassociation values, were not separable from each other once a 380 nucleotide long insertion had been removed from the sequence of the two S. apiospermum strains tested. The SSU rDNA of Ps. ellipsoidea is identical to that of Ps. boydii. Fungi which have been known to have Graphium anamorphs can be divided in at least three groups, one of which is related to Petriella and includes Graphium tectonae.

Ascomycota↗