The effect of prostaglandins A2,E1,E2,15 methyl E2, 16, 16 dimethyl E2 and F2 alpha on erythropoiesis.

Prostaglandins A2, E1, E2, methylated E2s, and F2 alpha affected erythropoiesis and/or erythropoietin (Ep) production. This action is indicated in the exhypoxic, polycythemic mouse where radioiron incorporations into RBC increased after administration of these compounds. The kidney and liver have been indicated through previous studies, to actively participate in Ep production.

Recovery of an erythropoietin inducing factor from the regenerating rat liver.

The perfusion of livers of partially hepatectomized (H mean) rats lends support to earlier findings that the regenerating rat liver is the source of an erythropoietin-inducing hepatic factor (Ep-IHF) which stimulates hepatic production of extrarenal erythropoietin (Ep). Blood plasma was collected from perfused livers of rats that were partially hepatectomized (H mean) 48 to 72 hrs prior to perfusion with whole blood from normal rats. This plasma, when injected into normal rats which were nephrectomized (N mean) and rendered hypoxic 18 hrs after injection, evoked a significant increase in Ep values when compared to blood plasma collected from perfused livers of normal rats.

A renal inhibitor to hepatic erythropoietin [Ep] production.

Evidence is presented for the existence of a factor in renal venous blood, evoked by subtotal hepatectomy (hepx), which inhibits the production of Ep in nephrectomized (nephrx) rats exposed to hypoxia. Significant inhibitory activity is not observed in blood obtained from sites other than the renal vein. This inhibitory effect is believed to be due to the action of a specific renal inhibitory factor (RIF) which reduces the extrarenal (hepatic) Ep response to hypoxia indirectly, by decreasing the production or effectiveness of an antagonistic liver principle, the hepatic erythropoietic factor (HEF).

A new organic solvent for use in the clearing of tissues. I. Soft tissue histology.

Histosol is a non-flammable solvent mixture of synthetic aromatic hydrocarbons with a flash point of 124 degrees F (T.C.C.

Evidence for a sexual variation in production of a hepatic erythropoietic factor by hepatectomized rats.

Erythropoietin (Ep) is a glycoprotein hormone that is responsible for mammalian red blood cell production. Adult rat liver regenerating 48-72 h after hepatectomy (hepx) produces elevated levels of Ep in response to hypoxia when compared to sham-operated, anephric hypoxic controls. A factor, termed hepatopoietin (Hp), found in the serum of hepx rats, is capable of stimulating hepatic Ep production when administered to normal rats 18 h prior to hypoxic exposure.

The effects of x-irradiation on mouse palatal epithelial chromosomes.

Low levels of X-ray exposure of mouse palatal epithelial cell cultures resulted in increased numbers of chromosomal aberrations. At the lowest level used (IR), aberrations occurred of the type produced by two breaks such as chromatid exchanges, dicentrics, and metacentrics.

Studies on the anemia of the Shay chloroleukemia.

The pathogenesis of the anemia which occurs in rats bearing the Shay chloroleukemia (SCL) was investigated. Severe anemia, shown not to result from hemodilution, developed in the terminal stage of the disease. The rapid progression of the anemia suggested that reduced erythropoiesis was of no more than minor importance in the development of this anomaly.

Hepatic erythropoietin (Ep) production following double partial hepatectomy in the rat.

Double partial hepatectomy (hepx) evokes an elevation in serum erythropoietin (Ep) levels in anephric hypoxic animals when compared to non-hypoxic or sham hepx controls. But this Ep response is significantly lower than that found in singly hepx, anephric hypoxic rats. Double hepx also induces numerous cytological changes in the liver.

The regenerating liver: a site of erythropoiesis in the adult Long-Evans rat.

Erythropoiesis, which is primarily hepatic in the rat during fetal and early neonatal life, shifts almost entirely to the bone marrow in the neonatal-adolescent stage of development. In the adult, extramedullary erythropoiesis has been demonstrated in the liver and spleen under certain pathological conditions when bone marrow red cell production is insufficient. In the present study, erythropoietic foci have been found in young-adult rat liver regenerating 24-72 hr after subtotal hepatectomy.

Biocompatibility evaluation of casting alloys in hamsters.

A number of base metal and low gold-content alloys were evaluated in hamster cheek pouches for biocompatibility. No adverse weight changes and no abnormal behavioral patterns were noted in any of the test groups over the 14-day period of the study. Gross examination of the cheek pouches containing the alloys was no different from that of the controls.

Reticuloendothelial system (RES) hyperfunction and erythropoietin (Ep) production in the regenerating liver.

Hepatic cells in rats were evaluated after subtotal hepatectomy using scintillation scanning with technetium sulfur colloid (TSC), autoradiography, and microstereology techniques. The ability of the liver to accumulate TSC increased during the course of the regeneration as did the labeling of Kupffer and parenchymal cells with tritiated thymidine (3H-tdR). Kupffer to parenchymal cell number ratios and Kupffer cell relative areas were also elevated, attaining peak values at 72 hours post-hepatectomy.

Histologic identification of mast cells in human dental pulp.

Previous investigators who attempted to identify mast cells in the dental pulp have used demineralizing or tooth-splitting procedures to obtain their tissue samples. However, Eda and Langeland15 found that the fluorescence of mast cells is destroyed by acid demineralizing agents. On the other hand, tooth splitting may damage the pulp by crushing it with forceps, or cutting and heating it with burs, stones, or discs.

Age-related variations in hepatic regeneration and erythropoietin production in the rat.

Erythropoietin (Ep) is produced mainly by the liver and spleen during fetal and neonatal periods and by the kidney during adolescent and adult life. The liver is also an important extrarenal producer of Ep in the hypoxic, anephric adult animal. Subtotal hepatectomy results in a substantial elevation in serum Ep levels at 30-72 hours after hepatectomy in rats subsequently nephrectomized and rendered hypoxic.

Hepatic regeneration and erythropoietin production in the rat.

The regenerating liver produces erythropoietin in response to hypoxia. The amounts of erythropoietin produced in animals subjected to hepatectomy are significantly higher than those observed in sham-operated animals. Hepatic erythropoietin production appears to be dependent upon the stage of regeneration with the highest levels being produced during the period of greatest proliferation and increase in liver mass.

Mechanisms underlying the suppression of erythropoiesis by hyperoxia.

The possible mechanisms underlying the suppression of erythropoiesis in hyperoxic animals were studied. Male Long-Evans rats were injected with cobaltous chloride hexahydrate, a known erythropoietic stimulant. One group was exposed to a hyperoxic environment for ten hours.

Isoproterenol-induced changes in cell cycle kinetics of parotid gland acinar cells in 8-day-old rats.

Isoproterenol (IPR) was shown to alter some parameters of the parotid gland acinar cell cycle in 8-year-old rats. Although the deoxyribonucleic acid (DNA) synthetic period (S) was decreased and the pre-DNA synthetic (G1) period was lengthened, there were no differences in the total cycle time. There was an increase in the 3H-thymidine labeling index from 35.

Composite materials for dental implants.

The requirements of endosteal dental implants are unique and stringent. The materials currently applied to implantation do not offer convincing evidence of satisfying these needs. This preliminary study reports on attempts at developing materials which would aid in obtaining a mucosal seal to maintain the integrity of the osseous, periosteal, and submucosal compartments from the oral environment and the attachment to bone as related to stress distribution.