Biomedical subjects

T Kuopio

Publications and source records attributed to T Kuopio.

45 records · Page 3Linked to original sources

PubMed1989

Developmental stages of fetal-type Leydig cells in prepubertal rats.

Fetal Leydig cells were studied in rats during and after the perinatal-neonatal period by comparing changes in morphology, number and volume with changes in testicular steroids and serum luteinizing hormone (LH) concentration. Stereologic examination indicated regression of fetal Leydig cells in testis by showing that their total volume as well as the average cell volume decreased between prenatal day 20 and postnatal day 3. The total number and total volume of cells both increased between postnatal days 3 and 11 but the average cell volume did not change during the same time period. Determination of serum LH showed a close correlation between an increase in LH concentration and increases in total number and volume of cells. The combined number of fetal- and adult-type Leydig cells on day 20 was more than 20 times the number of fetal cells at 3 days of age. Electron microscopic analysis showed that fetal Leydig cells after birth formed conspicuous clusters, which were surrounded by a layer of envelope cells and extracellular material. Occasional dividing fetal Leydig cells and possible precursors of fetal or adult Leydig cells were observed. Mitoses of spindle-shaped pericordal cells were frequent during the neonatal period. During and after the second postnatal week fetal Leydig cells again showed signs of regression, indicated by disintegration of the cell clusters, a decrease in cell size, accumulation of collagen between the cells and a decrease in steroid content per cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1989

Structural proteins in sexual differentiation of embryonic gonads.

Sexual differentiation of embryonic gonads was studied by immunocytochemical analysis of cytoskeleton, basement membrane and extracellular matrix. The epithelial cells of the prospective gonadal region in both sexes contained vimentin and desmin intermediate filament proteins but not cytokeratin. Basement membrane components laminin, collagen types IV and V, heparan sulfate proteoglycan, and fibronectin were seen in an unorganized form in the extracellular space. The development of the gonads started by proliferation of the pregonadal epithelial cells, which formed separate clusters and loose mesenchyme. In the male gonad the clusters joined together into elongated cords, outlined by basement membrane components. The cord cells became polarized epithelial cells, and cytokeratin appeared with the disappearance of desmin in their cytoplasm. Desmin and vimentin remained in the interstitial cells. In the female gonad the clusters were smaller, and the cords were irregular in shape and size. Desmin disappeared from the cord cells and cytokeratin appeared, but more slowly and less well polarized than in the testis. The present results show that after common early development, the sexual differences in gonads emerge as different organization of the internal epithelial tissue with different timing of changes in intra- and extracellular components.

Animals↗

PubMed1984

Rat testicular endogenous steroids and number of Leydig cells between the fetal period and sexual maturity.

Endogenous androgens (androstenedione, testosterone, 5 alpha-dihydrotestosterone and 5 alpha-androstane-3 alpha,17 beta-diol), and some of their C21 precursors (pregnenolone, progesterone and 17-hydroxyprogesterone) were measured in rat testes between Day 18.5 of pregnancy and Day 64 postpartum, and correlated with numerical densities of Leydig cells. The latter parameter showed an early maximum on Day 19.5 of the fetal period, a nadir on Day 15 postpartum, and a gradual increase thereafter. The two dominating androgens, testosterone and 5 alpha-androstane-3 alpha,17 beta-diol, had similar levels until 15 days of age, but the 5 alpha-diol predominated thereafter. The total steroid content per Leydig cell was highest on Day 18.5 of gestation (77 ng/10(6) cells). A decline started already in utero, and reached a nadir of 5 ng/10(6) cells on Day 29. Thereafter, a slight increase occurred with advancing age. It is concluded that: The fetal testis has highest Leydig cell and endogenous steroid concentrations. A nadir in these parameters is seen 2-4 wk postpartum. The Leydig cell concentration increases around puberty on Days 40-60, but only a slight concomitant increase occurs in steroids. A sharp decline in steroid content per Leydig cell occurs during the last fetal days, but the postnatal decline of testicular steroids is due to Leydig cell loss. The new Leydig cell generation after 15 days has a persistently low steroid concentration through puberty.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgens↗

PubMedDate not supplied

Transplantation of newborn rat testis under the kidney capsule of adult host as a model to study the structure and function of Leydig cells.

Newborn rat testis was transplanted under the kidney capsule of adult castrated and uncastrated male rats to develop and characterize a model system for studies on Leydig cell development. Two weeks after transplantation, the number of Leydig cells and the size of their nuclei in the transplants had increased. Secretion of testosterone was indicated by increased seminal vesicle weights and decreased pituitary LH in the castrated host animals. Pituitary FSH content increased significantly in the uncastrated animals with transplants, which suggested production of an FSH-stimulating factor. Cells with the morphologic features characteristic of fetal- and adult-type Leydig cells were observed in the transplants. The seminiferous tubules with spermatocytes, incipient lumina, and significantly larger average diameters showed more advanced development than those in the normal 2-week-old testis. By the present morphologic and functional criteria, the kidney subcapsular transplantation technique provides a suitable model for studies of fetal and adult Leydig cell development.

Animals↗

PubMedDate not supplied

Ultrastructure and immunohistochemistry of a fetal-type Leydig cell tumor.

A symptomless scrotal mass was removed from a 34-year-old man. The lesion was 7 cm in diameter and it was grossly a hemorrhagic cyst with indurated walls. By light microscopy tumor cell clusters and cords were seen infiltrating the testicle, tunica albuginea, and paratesticular tissue. In the immunohistochemical analysis the tumor cells were immunoreactive with anti-S-100 protein and anticarcinoembryonic antigen, but they did not express cytokeratin or alpha-fetoprotein as tested with paraffin sections. Tumor cell clusters were enveloped by a laminin-positive basement membrane. Electron microscopy revealed abundant smooth endoplasmic reticulum, lipid droplets, and membranous whorls in the cytoplasm. Lamellar whorled bodies were also seen in mitochondria, which contained tubulovesicular cristae. The presence of a well-developed, often multilayered basement membrane was confirmed at ultrastructural level. The activity of 3-beta-hydroxysteroid dehydrogenase suggested that the tumor cells were capable of androgen synthesis. The morphological features are reminiscent of fetal-type Leydig cells and are distinctly different from the Leydig cell tumors described so far.

Adult↗

PubMedDate not supplied

Interpretation guidelines of DNA histograms from tissue sections of breast cancer.

BACKGROUND: Evaluation of nuclear DNA staining intensity from histological breast cancer sections has not always been accepted, because of the difficulties in interpreting the histograms. One reason for this is the lack of evidence based interpretation guidelines. MATERIALS AND METHODS: The DNA staining intensity of 140 breast cancer samples was measured with flow cytometry (FCM) and image cytometry (ICM). The methods were compared by using grading efficiency (GE). RESULT: First, the ICM histograms were evaluated with a computer assisted image cytometry system using different cut off points for aneuploidy. The GE results varied from 67.9-76.4%. Subjective interpretation and evaluation according two previously published interpretation methods did not improve the GE. Secondly, we excluded histograms which showed clearly different cell clones in FCM and ICM. The GE of remaining histograms was 77.9%. Comparison of these histograms allowed formulation of interpretation guidelines which improved the GE to 85.3%. CONCLUSIONS: This study suggests that efficient interpretation guidelines of section-based DNA histograms can be created.

Aneuploidy↗

PubMedDate not supplied

Bcl-2 immunostaining: a way to finding unresponsive postmenopausal N+ breast cancer patients.

BACKGROUND: Bcl-2 staining positivity has shown limited prognostic value. However, we have decided to study this issue in the era of mammography screening, and adjuvant treatment protocols. METHODS: Paraffin sections of 414 breast cancers were stained for bcl-2 and staining intensity graded. Association of bcl-2 with established prognosticators was analysed with chi 2 test and odds ratios in 2 x 2 tables. Kaplan-Mayer analysis and Cox's regression were used to evaluate the prognostic value of bcl-2 and other prognosticators. RESULTS: Bcl-2 immunostaining was associated with tumor size, lymph node status, histological type, multivariate prognostic index, standardized mitotic index, Ki-67 fraction, DNA-index, proportion of cells with DNA above 5c, estrogen receptor status, and histological grade. ER status showed the best association with bcl-2 positivity (odds ratio 11.3, 95% CI 5.6-22.7). In the whole group of patients bcl-2 positivity was not an independent prognosticator. However, among N+ patients bcl-2 staining was significant, and among postmenopausal N+ patients bcl-2 immunostaining was a stronger independent prognosticator than tumor size. CONCLUSIONS: The prognosis of N+ breast cancers can potentially be evaluated with bcl-2 positivity, in association with tumor size, and mitotic activity. Among postmenopausal N+ patients, most of whom have received anti-estrogen therapy, bcl-2 positivity is an independent prognosticator. Also, the close association of bcl-2 positivity with ER status supports the view that bcl-2 negativity reveals a patient group which might benefit from additional treatment in association with anti-estrogen therapy.

Breast Neoplasms↗

PubMedDate not supplied

Nuclear volume and breast cancer prognosis.

BACKGROUND: In breast cancer, nuclear volume estimates can be expected to be better prognosticators than nuclear profile areas because biological variation is wider in volume estimates than in area measurements. MATERIALS AND METHODS: 191 invasive breast cancer samples were available for nuclear volume measurements. To estimate the volume weighted mean nuclear volume, point-sampled linear intercepts were used on micrographs. The nuclear profile area was measured from 148 cases matching volume measurements and run by the Prodit morphometry program. Measurements were compared as prognosticators after a follow-up of 5 years. A computerized method on a randomly selected large number of nuclei was also applied in 17 cases. Bcl-2 immunostaining was compared with nuclear measurements. RESULTS: The correlation of volume and area measurements was statistically significant, but the correlation coefficients were low. The nuclear area showed a significant difference in survival at the 75 percentile cut-point but the volume-weighted mean nuclear volume did not allow distinction of different prognostic groups. Computerized volume measurements based on a large number of nuclei and measurements based on the simpler method did not show statistically significant correlation. Bcl-2 staining did not show any correlation with volume or area measurements. CONCLUSIONS: Although the prognostic value of nuclear area was shown in our study, the volume-weighted mean nuclear volume did not show prognostic significance. Improvement of the methodology which could decrease method variation and increase reproducibility of measurements is urgent for verification of the prognostic value of nuclear volume measurements. Bcl-2 immunostaining and nuclear area measurements were independent prognostic variables.

Breast Neoplasms↗

PubMedDate not supplied

Breast cancer in Nigeria and Finland: epidemiological, clinical and histological comparison.

BACKGROUND: We compared the histology and patterns of occurrence of breast cancers in Nigeria (n = 297) and Finland (n = 285). PATIENTS AND METHODS: The histology of invasive ductal carcinoma (IDC) was re-evaluated using similar criteria. The clinical data were extracted from medical records. RESULTS: The mean age at presentation was 42.7 (12.2) years in Nigeria vs. 58.7 (12.5) years in Finland. In both populations there was an association between reproductive factors and the occurrence of breast cancer. In Nigeria, 53.2% of cases belonged to stages 3 and 4 (vs. 6.7% in Finland). In Finland there were higher frequencies of lobular, tubular and mucinous types than in Nigeria. The Nigerian material had more medullary type (2.7% vs. 0.7% in Finland), extensive necrosis, nuclear atypia and pleomorphism, with coexisting pleomorphic ductal carcinoma in situ. At 2 years after treatment, the survival figures for Nigeria and Finland were 72.8% and 96.4%, respectively. CONCLUSION: The histology of Nigerian and Finnish cancers clearly differ. Nigerian cancers appear more advanced with higher grade. The atypical in situ component is clearly more common in Nigeria. Part of the differences can be explained by diagnostic and treatment delays associated with misguided socio-cultural beliefs, poor health care access and impaired immunity.

Adolescent↗