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Biomedical subjects

E Eerola

Publications and source records attributed to E Eerola.

At least 91 records · Page 5Linked to original sources
PubMed1987

Diagnostic value of flow cytometric DNA determination combined with fine needle aspiration biopsy in thyroid tumors.

The nuclear DNA content and the numbers of cells in the S and G2M phases of the cell cycle were determined by flow cytometry (FCM) in fine needle aspirates of 187 thyroid tumors to evaluate the diagnostic value of nuclear DNA content determination in combination with aspiration cytology. DNA aneuploidy was present in 4 of 5 follicular carcinomas, 2 of 3 anaplastic carcinomas, 5 of 15 excised follicular adenomas and 2 of 20 excised adenomatous goiters; all 7 papillary carcinomas and 4 lymphomas were diploid in the aspirate. Aneuploid carcinomas had easily distinguishable S and/or G2M phases, unlike the benign aneuploid tumors. None of the histologically benign tumors or the nonexcised tumors had greater than 6% S-phase cells, and only one benign tumor had greater than 9% G2M-phase cells. In contrast, all lymphomas had greater than 10% S-phase cells and four of seven papillary carcinomas had greater than 9% G2M-phase cells. The use of FCM determination in combination with fine needle aspiration biopsy cytology improved the diagnostic potential of the latter technique.

Adenocarcinoma↗
PubMed1986

Influence of cellular DNA content on survival in differentiated thyroid cancer.

Cellular DNA content was measured using a novel flow cytometric method to analyze paraffin-embedded tissue blocks from 125 patients with differentiated thyroid cancer. DNA aneuploidy was found in 20 (24%) of the 82 papillary, 20 (56%) of the 36 follicular, and in four (57%) of the seven medullary carcinomas. Aneuploidy was found to be more common in the elderly (P less than 0.002), in moderately and poorly differentiated carcinomas (P less than 0.004), and in tumors infiltrating beyond the thyroid capsule (P less than 0.03). Patients with an aneuploid tumor had less favorable cumulative survival (P less than 0.0001) than patients with diploid cancer. However, in papillary and follicular carcinomas, multivariate analysis using stepwise Cox model showed age at diagnosis, follicular type, and tumor invasion beyond the thyroid capsule to be more important independent prognostic factors. Increasing probability of DNA aneuploidy with increasing age explains partially why prognosis of differentiated thyroid carcinoma is poor in older patients.

Age Factors↗
PubMed1986

Uracil-DNA glycosylase activity in chronic lymphoproliferative disorders.

The activity of uracil-DNA glycosylase, a repair enzyme for the excision of uracil from DNA, was studied in patients with chronic lymphoproliferative disorders and with malignant plasma cell dyscrasias. The biochemical assay was performed on mononuclear cells, isolated by density gradient centrifugation from peripheral blood, from bone marrow or from both. The activity of the uracil-DNA glycosylase of peripheral blood cells in 8/8 cases of myeloma and in 3/3 cases of Waldenström's macroglobulinemia was in the same range as in 22 non-hematological control patients, i.e. 2.4-25.1 U/mg of protein. Higher activities were found in 9/12 cases of chronic lymphocytic leukemia (CLL), in 2/4 cases of hairy cell leukemia (HCL), in 2/2 cases of chronic T-cell lymphocytosis and in the only case of small cell lymphocytic lymphoma. Follow-up of some CLL and HCL patients revealed that uracil-DNA glycosylase activity was fairly stable during the course of the disease. We conclude that malignant cells in chronic lymphoproliferative disorders are characterized by a normal or even increased capability to repair DNA, as exemplified by uracil-DNA glycosylase in this study.

Adult↗
PubMed1986

Rat spermatogenesis in vitro traced by quantitative flow cytometry.

In vitro differentiation of germ cells in rat seminiferous tubule segments at stages II-III of the epithelial cycle was studied. DNA flow cytometry was used for quantitation of absolute cell numbers from the cultured tubule segments that were compared to freshly isolated stages of the cycle, as identified by transillumination stereomicroscopy of the seminiferous tubules and phase-contrast microscopy of live cell squashes. Spermatogonia and spermatocytes from stages II-III showed normal morphological differentiation during 7 days in vitro. Round spermatids differentiated to Step 7 of spermiogenesis but Step 16 spermatids failed to develop. Acid phosphatase activity in the spermatogenic cells changed normally during the culture. As compared with freshly isolated control tubule segments, 35% of round spermatids and 42% of pachytene spermatocytes were present in culture after 7 days. The cell numbers recovered from defined stages by DNA flow cytometry were close to those found in morphometric studies. Flow cytometry is an efficient quantitation method for cells liberated from seminiferous epithelium. Spermatogonia, spermatocytes, and early spermatids are able to differentiate in vitro, but spermatids approaching the elongation (acrosome) phase, and particularly the maturation phase, fail to differentiate under present culture conditions.

Acid Phosphatase↗
PubMed1986

Regulation of stages VI and VIII of the rat seminiferous epithelial cycle in vitro.

Plasminogen activator (PA) is secreted cyclically (in stages VII and VIII) by rat seminiferous tubules. To investigate whether this can be maintained and influenced in vitro, tubule segments from stages VI and VIII of the epithelial cycle were cultured for 3 days in chemically defined medium supplemented with testosterone, FSH, or a combination of testosterone, FSH, insulin and retinoic acid (4F). Morphological and flow cytometric analyses of stage VI tubules suggested a roughly normal differentiation to stage VIII. They developed an increased PA secretion on day 3 of culture. Stage VIII tubules, however, did not develop all the characteristics of stage XII. Step 8 spermatids did not elongate and step 19 spermatids failed to develop into spermatozoa. Secretion of PA on day 3 was not significantly different to that on day 1. The 4F combination very significantly stimulated PA secretion in both stages, but FSH alone was effective only in stage VIII. Most of the secreted PA had a molecular weight of 43,000 in both stages, suggesting that it is of urokinase type. The results suggest that stage VI is more able to differentiate in vitro for 3 days than stage VIII; the cyclic secretion pattern of PA was partially maintained in tubule segments from stage VI. Follicle-stimulating hormone had an effect on PA secretion only in stage VIII, whereas the 4F combination was stimulatory in both stages. The retinoic acid in this combination may be of importance in the regulation of PA secretion by seminiferous tubules.

Animals↗
PubMed1986

DNA aneuploidy in follicular adenomas of the thyroid gland.

The nuclear DNA content of 67 follicular adenomas and 7 adenomatous goiters was determined by flow cytometry. The DNA analysis was done with the use of paraffin-embedded tissue, but in 14 cases of follicular adenoma fresh material obtained by fine needle aspiration biopsy was also available. An abnormal DNA stemline was found in 27% (18/67) of the adenomas and in 1 (14%) of the adenomatous goiters. Four (29%) of the 14 adenomas analyzed from fresh samples were aneuploid. In none of the 12 aneuploid or 40 diploid adenomas followed for more than 5 years (mean, 7.2 years) did distant metastases develop after surgical removal of the adenoma. The paraffin blocks of cases with DNA aneuploidy were sectioned subserially at 1-mm intervals, but none of these tumors showed invasion into the capsule or blood vessels. It is concluded that DNA aneuploidy is common in histologically benign follicular adenomas of the thyroid, and that DNA aneuploidy does not appear to be associated with adverse prognosis in follicular adenomas if the tumor is surgically removed.

Adenoma↗
PubMed1985

Determination of callus quantity in 4-week-old fractures of the rat tibia.

In clinical practice the quantity of fracture callus is usually estimated on the basis of radiographs. In experimental studies on fracture healing, more exact chemical measurements (total protein, DNA, and mineral contents) have been used to quantitate the amount of callus. It is not known, however, how these two parameters correlate with each other. In this study we used different (radiographic, histomorphometric, and chemical) methods to evaluate the quantity of fracture callus in 4-week-old tibial fractures of rats stabilized by intramedullary nailing. The wet and dry weights and the nitrogen, collagen, calcium, phosphorus, and DNA contents of the calluses showed no correlation with the radiographic size of the calluses. There was a strong correlation (p less than 0.001), however, between radiographic and histomorphometric callus sizes. The mass of callus and the chemically defined parameters of callus production thus indicate different properties of the healing bone.

Animals↗
PubMed1985

Lymphoid cell chimerism and transplantation tolerance induced by bursal and postbursal cells.

Transplantation of allogeneic bursal cells into cyclophosphamide-treated, immunodeficient chickens is a useful experimental model for analyzing the mechanisms of transplantation tolerance, especially because transplanted bursal cells do not produce graft-versus-host disease. In this study we have determined B-lymphoid chimerism in various lymphoid organs after transplantation of allogeneic bursal stem cells or postbursal cells, and used a variety of tests to determine presence of immunological tolerance. Transplanted bursal stem cells induced a state of stable chimerism that could easily be detected in peripheral blood and other lymphoid organs. Chimerism induced by postbursal cells was low in peripheral blood, but clearly observable in other lymphoid organs, especially in spleen and thymus. Both bursal and postbursal cells induced specific unresponsiveness to donor-line alloantigens. Bursal cell recipients accepted donor line skin grafts--and their graft-versus-host reactivity, as assayed by embryonal splenomegaly, and mixed lymphocyte reactivity against donor line alloantigens were significantly decreased. Despite differences in chimerism, a strong transplantation tolerance was readily induced with bursal stem cells and with postbursal cells.

Animals↗
PubMed1985

Fracture healing in paraplegic rats.

In paraplegic rats, histomorphometric and chemical methods were used to evaluate callus production in tibial fractures stabilized by intramedullary nails. There were no differences in the mean sizes of fracture callus between paraplegic rats and their non-weight-bearing and weight-bearing controls. However, the variance of callus size was large in paraplegic rats. The concentration of nitrogen was high in calluses of paraplegic rats during the cartilaginous stage of healing. The hydroxyproline concentration did not differ between the groups. The rate of callus ossification was more rapid in paraplegic rats than in controls, but fracture calluses of paraplegic rats showed delayed accumulation of calcium and incomplete maturation of woven new bone. The results suggest that there are both mechanical and non-mechanical factors affecting callus formation in fractures below a spinal lesion.

Animals↗
PubMed1985

Development of nonunions in the rat fibula after removal of periosteal neural mechanoreceptors.

Periosteal proprioceptive nerve receptors may act as mechanoreceptors of long bones during adaptive remodeling after fracture. They may also contribute to the mechanisms of coordinated functional activity of fractured limbs and thus inhibit harmful overloading of fracture callus. The area of proprioceptive nerve receptors around the distal part of the rat fibula was stripped surgically, and a standard fracture of the fibular shaft was produced. Animals failed to unite their fractures and developed mainly atrophic nonunions. Atrophy of ununited fragments was due to osteoclastic bone resorption. Atrophy of the bone fragments was aggravated if the legs were also subjected to sciatic denervation. Sciatic denervation alone, without removal of receptors, did not interfere with the union of fractures. The results indicate that the area of proprioceptive receptors in the rat tibiofibular bone is critical for the healing of fibular fractures. Because the effect on bone healing of receptor removal was not inhibited by sciatic denervation, the effect was not transmitted through spinal pathways of the sciatic nerve. The development of nonunions could not be explained by the surgical trauma alone. Aggravation of fibular atrophy by sectioning of the sciatic nerve suggests that some neural elements are associated with the phenomenon, either directly or indirectly through neuromuscular function.

Animals↗
PubMed1984

Electrostimulation of rat callus cells and human lymphocytes in vitro.

Asymmetrical pulsing low voltage current was supplied via electrodes to cultured rat fracture callus cells and human peripheral blood lymphocytes. The [3H]thymidine incorporation of the callus cells and 5-[125I]iodo-2'-deoxyuridine incorporation of the lymphocytes were determined. The growth pattern of callus cells (estimated by cellular density) did not respond to electrical stimulation. However, the uptake of [3H]thymidine was increased at the early phase of cell proliferation and inhibited at later phases of proliferation. The [3H]thymidine uptake of confluent callus cell cultures did not respond to electrical stimulation. Lymphocytes reacted in a similar way; stimulated cells took up more DNA precursor than control cells at the early phase of stimulation. During cell division, induced by the mitogens phytohemagglutinin and Concanavalin-A, the uptake of DNA precursor by stimulated cells was constantly inhibited. The results suggest that electrical stimuli affect the uptake mechanisms of cell membranes. The duality of the effect seems to be dependent on the cell cycle.

Animals↗
PubMed1984

Tissue oxygen tension in externally stabilized tibial fractures in rabbits during normal healing and infection.

Permanently implanted Silastic tonometers were used to measure average extracellular oxygen tension in the medullary cavity of osteotomized rabbit tibias stabilized with external pin fixation. During uncomplicated healing the baseline bone pO2 rose slowly with time from 10 to 20 mm Hg while during staphylococcal infection pO2 varied between 8 and 15 mm Hg and showed no correlation with the healing time. The maximal response of the bone pO2 to oxygen breathing correlated linearly with the healing time whether the osteotomy was infected or not. On the 42nd day the maximal pO2 during systemic hyperoxia was 85 mm Hg for the control bones, 42 mm Hg for the osteotomized bones, and 30 mm Hg for the infected osteotomized bones. The results indicate moderate bone tissue hypoxia during uncomplicated healing and more profound hypoxia during healing affected by infection.

Animals↗
PubMed1984

Immune capacity of the chicken bursectomized at 60 hr of incubation: effect of adherent cells on the production of immunoglobulins and specific antibodies in vitro.

Cells from chickens bursectomized at 60 hr of incubation (Bx) and normal controls (Co) were assessed for the ability to secrete immunoglobulins and specific antibodies in vitro. Anti-tetanus antibodies were observed in the culture supernatants of cells from tetanus-immunized Co chickens. Cells from immunized Bx and nonimmunized Co chickens did not secrete specific antibodies. Cells of both Bx and Co chickens secreted similar amounts of immunoglobulins (IgM, IgG, IgA). Antigenic stimulation in vitro had no effect on the secretion of specific antibodies or on cell proliferation; this applies for Bx and Co chickens. To test whether antigenic stimulation in vitro together with adherent cells would induce antibody production in Bx cells, cocultures of peripheral blood adherent cells and lymphocytes from spleen or peripheral blood were used. Culture of lymphocytes with histocompatible and allogeneic adherent cells, with or without antigenic stimulation, did not enhance secretion of anti-tetanus antibodies from cells of Bx chickens. The adherent cells increased the secretion of total immunoglobulins, of all classes, by both Co and Bx cells alike. They also enhanced the secretion of specific antibodies by Co cells. These findings indicate that the functional failure of Bx lymphoid cells cannot be corrected by better antigenic presentation.

Animals↗
PubMed1984

Immune capacity of the chicken bursectomized at 60 H of incubation. Effect of bursal epithelial cells and bursal epithelium-conditioned medium on the production of immunoglobulins and specific antibodies in vitro.

Cells from chickens bursectomized at 60 h of incubation (Bx) are known to produce immunoglobulins without any detectable antibody specificity. In the present work cells from Bx birds were cultured together with bursal epithelial cells (BE) or bursal epithelium-conditioned medium (BECM) to establish whether they could be induced to produce specific antibodies. Cells obtained from 10-day-old or 10-week-old birds were used. The effects were assessed with regard to the production of total immunoglobulins and specific antibodies; the birds had been preimmunized. BE had no effect on the production of immunoglobulins by either Bx or control (Co) cells. When cells from 10-week-old birds were cultured in the presence of BECM, no difference in the immunoglobulin production was seen between Bx and Co chicken cells. At the age of 10 days the cells of Bx birds produced considerably less Ig than the cells of normal Co birds. At this age BECM had no effect on the Co cells, but it markedly enhanced the production of IgA-class immunoglobulins of Bx birds. With regard to production of specific anti-tetanus antibodies, BE stimulated the production of IgA-class antibodies by cells from preimmunized Co chickens but had no effect on cells from preimmunized Bx birds. In spite of the normal production of immunoglobulins in vitro the cells of Bx chickens did not produce specific antibodies. In conclusion, these findings indicate that if B cells have matured without a contact with the bursa of Fabricius, later in vitro exposure to BE or BECM can no longer induce them to production of specific antibodies.

Aging↗
PubMed1983

Intrafamilial spread of pertussis.

Intrafamilial spread of pertussis was evaluated in 21 families (97 individuals) of patients with whooping cough diagnosed by culture or by ELISA serology. During follow-up (average six months), an infectivity rate of 83% was established by an ELISA within these families. However, 46% of the secondary cases were asymptomatic. Most of the asymptomatic cases were in adults or vaccinated children. Unvaccinated infants had classic whooping cough and were exposed to pertussis by their vaccinated siblings or parents. The incidence of classic symptoms of pertussis decreased with age, and atypical pertussis was usually culture negative but rapidly diagnosed by measurement of the IgM- and IgA-class antibodies by ELISA.

Adolescent↗
PubMed1983

Characteristics of chicken intraembryonic cells that express B-L (Ia-like) antigen under the influence of cultured bursal epithelium.

In-vitro-cultured bursal epithelium (BE) and BE-conditioned medium (BECM) induce B-L antigen on chicken intraembryonic cells. Cells prepared from 9-day-old intraembryonic mesoderm were fractionated in accordance with cell size by linear albumin gradient sedimentation at 1 g. Two cell types could be distinguished on which expression of the B-L antigen was altered after a 6-h incubation with the bursal epithelial component. One fraction contained small mononuclear cells with low sedimentation velocity (less than or equal to 3 mm/h) and low spontaneous proliferation activity. These cells responded strongly to BECM and showed a slight but not significant response to BE (index after incubation with BECM 3.8, with BE 1.7, as compared with RPMI medium control). The other fraction was composed of large mononuclear cells with sedimentation velocity greater than 9 mm/h and with high spontaneous proliferation. These cells showed a response of equal magnitude to both BE and BECM (index after incubation with BE 2.0, with BECM 2.3). These results suggest that the bursa of Fabricius has influence on two different cell types: a large, probably primitive undifferentiated cell, responding equally to bursal cellular contacts and BE culture supernatant, and a small mononuclear cell type, probably more mature, responding more clearly to the bursal humoral factor.

Animals↗