Differential effects of cyclic AMP on DNA synthesis by germ cells and non-germ cells in mouse testicular culture

The effect of dibutyryl cyclic AMP (dbcAMP) on DNA synthesis in mouse cryptorchid explants with only type A spermatogonia was examined in vitro. Low concentration of dbcAMP (0.08 mmol/l) stimulated DNA synthesis by germ cells but inhibited that by non-germ cells.

Testicular DNA synthesis in vivo: changes in DNA synthetic activity following artificial cryptorchidism and its surgical reversal

The kinetics of DNA synthesis of whole testis in mice was studied in artificial unilateral cryptorchidism and in its surgical reversal. Cryptorchidism impaired total testicular DNA synthesis. Approximately 1 month after the operation, activity of testicular DNA synthesis decreased to about 30% that of the contralateral intact testis. A complete recovery of DNA synthesis was observed within 1 month after the surgical reversal of cryptorchidism.

Cell-surface changes accompanying aging in human diploid fibroblasts: effects of tissue, donor age and genotype

The generality of age-related changes in concanavalin A (Con A)-mediated red blood cell (RBC) adsorption to human diploid fibroblasts was investigated on fibroblast-like cells from fetal lung, heart, liver, skin and muscle tissues. All the cells examined showed the continuous increase from early passages in RBC adsorption with the RBC coating method (in which Con A-coated RBCs are adsorbed to fibroblasts) and the incraease only at phase III with the fibroblast coating method (in which RBCs are adsorbed to Con A-coated fibroblasts). All of the four strains of lung fibroblasts gave nearly the same extent of the age-related change in RBC adsorption, when expressed as a function of percentage life span consumed, indicating that the change in RBC adsorption is independent of genetic heterogeneity and conditions of primary culture. Liver and heart fibroblasts also gave results similar to those of lung fibroblasts. However, skin and muscle fibroblasts were lower in their RBC adsorption capacity throughout the life span. The continuous age-related increase in RBC adsorption to these cells could be sensitized by using glutaraldehyde-prefixed RBCs, trypsinized RBCs or phytohemagglutinin P in place of Con A. The relevance of the phenotype of in vitro aging revealed by RBC adsorption to in vivo aging was also demonstrated on skin fibroblasts from different ages of donors using glutaraldehyde-prefixed RBCs. In addition, fibroblasts from patients with Werner's syndrome, an hereditary disease manifested by early and widespread degenerative changes, showed senescent phenotype in RBC adsorption even at early passages.

Effects of glutaraldehyde and other drugs on concanavalin A-mediated red blood cell adsorption to nonsenescent, senescent and transformed human fibroblasts

Concanavalin A (Con A)-mediated red blood cell (RBC) adsorption with the RBC coating method (in which Con A-coated RBC's are adsorbed to fibroblasts) was greatly increased by glutaraldehyde fixation of RBCs before Con A-coating and decreased by the fixation of fibroblasts. On the other hand, RBC adsorption with the fibroblast coating method (in which RBCs are adsorbed to Con A-coated fibroblasts) was decreased by the fixation of RBCs and increased by the fixation of fibroblasts before Con A coating. The fixation of RBCs or fibroblasts after Con A coating did not have these effects. In addition, the fixation of both RBCs and fibroblasts nearly completely abolished RBC adsorption with either method. However, the amount of [3H] Con A binding was not affected by the fixation. RBC adsorption with the fibroblast coating method was also affected by cytochalasin B, colchicine, NaN3 and dibucane treatments of fibroblasts. These drug treatments of fibroblasts, however, did not affect RBC adsorption with the RBC coating method, except cytochalasin B. In addition, the effects of drug treatments of fibroblasts examined occurred nearly to the same extent for nonsenescent, senescent, and transformed cells. Our results suggest that secondary processes after Con A binding, receptor mobility and receptor association with cytoskeletals, play important roles in RBC adsorption, but that the roles do not change with aging or transformation.

Age-related cell surface changes in human diploid fibroblasts revealed by lectin-mediated red blood cell adsorption assay: a lectin survey

Two types of age-related cell surface changes could be demonstrated in human diploid fibroblasts with the two methods of the lectin-mediated red blood cell (RBC) adsorption assay: the fibroblast coating method (in which RBCs are adsorbed to lectin-coated fibroblasts) and the RBC coating method (in which lectin-coated RBCs are adsorbed to fibroblasts). With the fibroblast coating method, concanavalin A and agglutinin L from Phaseolus vulgaris gave a change in RBC adsorption which did not occur throughout the phase II period, but increased with the advance of the phase III period (type I). With the RBC coating method, these lectins gave another type of change in RBC adsorption which increased continuously from early phases of cell passage up through cell senescence (type II). Ricinus communis agglutinin 120 also gave the type I change in RBC adsorption with the fibroblast coating method. On the other hand, even with the fibroblast coating method, Phaseolus vulgaris agglutinin E and wheat-germ agglutinin gave the type II change in RBC adsorption. Soy bean agglutinin and Bauhinia purpurea agglutinin gave only a restricted amount of RBC adsorption. Lens culinaris agglutin, pokeweed mitogen, Dolichos biflorus agglutinin, Lotus tetragonolobus agglutinin, Limulus polyhemus agglutinin and divalent succinylated concanavalin A did not give any RBC adsorption throughout the life span of human diploid fibroblasts.

A new cell surface marker of aging in human diploid fibroblasts

The relationship of cell surface changes to proliferative decline of human diploid fibroblasts was investigated using the concanavalin A-mediated red blood cell adsorption assay. The amount of the red blood cells adsorbed to human diploid fibroblasts via concanavalin A increased continuously from the early phases of cell passage up through cell senescence, while the amount of 3H-concanavalin A binding did not change to a significant extent. The red blood cell adsorption is not a function of cell cycle phase and time spent in culture. Cocultivation of young cells with old cells also did not affect the adsorption capacity of respective cells. Thus, the concanavalin A-mediated red blood cell adsorption can be expected to serve as a new cell surface marker for aging in vitro. Using this marker, it was revealed that transient cell size or 3H-thymidine incorporating capacity di not have a direct relationship with the division age of a cell. Small rapidly dividing cells in old populations resemble large slowly dividing or nondividing cells of the same populations and differ from small rapidly dividing cells in young populations, in terms of cell surface properties.

In-vitro differentiation of type A spermatogonia in mouse cryptorchid testis

Cryptorchid testes from adult mice were incubated in calf serum-supplemented medium. There was an effective differentiation of adult type A spermatogonia up to the pachytene stage of meiotid division whcih resembled the process of spermatogenesis in vivo. In the absence of calf serum, type A spermatogonia did not differentiate at all. They differentiated when the serum was present for the first day, but was absent for the rest of cultivation. These results indicate that serum is necessary for only the early process of spermatogenesis from type A spermatogonia in vitro and not for the further processes of germ cell differentiation. Type A spermatogonia cultured in serum-free medium retained the ability to differentiate for at least 3 days.

Capsimycin, a new antibiotic. I. Production, isolation and properties

Capsimycin is a new antifungal antibiotic produced by a strain of Streptomyces sp. C 49--87. The active substance in the fermented broth was isolated by solvent extraction followed by silica gel column chromatography. The antibiotic melts at 186 degrees C (decomp.) and has a molecular formula C30H40N2O6. It exhibits marked inhibitory activity against Phytophthora capsici (Leaf blight disease of cucumber) and Pythium debaryanum (Damping-off disease of cucumber).

Temperature sensitivity of DNA synthesis in mouse testicular germ cells in vitro

The effect of temperature on testicular DNA synthesis in mice was studied in vitro. By using cultures of cryptorchid testis, DNA synthesis of differentiated germ cells, such as intermediate and type B spermatogonia and resting primary spermatocytes, was shown to be temperature-sensitive, while that of undifferentiated type A spermatogonia was not. DNA synthesis of non-germ cells was not temperature-sensitive. This temperature sensitivity of germ cells in DNA synthesis may be one cause of the thermal inhibition of germ cell differentiation.

Testicular germ cell differentiation in vivo

The effects of artificial cryptorchidism and surgical reversal on spermatogenesis were examined in mice. Only undifferentiated type A spermatogonia were present as germ cells in cryptorchid testes. The surgical reversal of cryptorchidism resulted in regenerative differentiation of mature germ cells as judged by testicular weight, histologic examination, and increase in the specific activity of lactate dehydrogenase-X. Leydig cell function was also examined by assessment of the weight of target tissues of androgen. They showed a unique change following the surgical reversal. Thirty days after surgical reversal, hyperfunction of the Leydig cells was observed, and the testes became normal after 60 days.

Clear cell carcinoma of the ovary: light and electron microscopic studies

Twelve cases of ovarian clear cell carcinoma were studied histologically. Four cases were examined electron microscopically and compared with other conditions. Five tumors were directly connected with ovarian endometriosis. They were histologically classified into a tubular type with hobnail cells and a solid type without tubular pattern or hobnail cells. Electron microscopic figures of the tumor cells are identical having large nuclei, abundant glycogen, lamellated RER, few lipid droplets, and sparse but well-developed microvilli. The basophilic dark cells frequently encountered in the tubular type are morphologically quite similar to clear cells excepting for sparsity of glycogen and lipid droplets. Alveolar arrangement of 6 to 10 tubular structures (honeycomb structure) resembling alveolate structure seen in late secretory endometrium was found in tumor cells of one case. Ultrastructural feature of clear cell carcinoma closely resemble those of Arias-Stella endometrium and clear cell carcinoma of endocervix suggesting their Muellerian origin.