Transplantation of a tooth involved in dentigerous cyst

To salvage an uneruputed tooth within a dentigerous cyst, the retransplantation of the unerupted premolar involved in the dentigerous cyst was performed. In the present case a dentigerous cyst with the impacted maxillary second premolar of a 10-year-old boy was removed, because of the missing eruption after marsupialisation of the premolar 4 months earlier. Covering the crown and the one third of root, the cyst was removed from the tooth, and the premolar was retransplanted into a cavity created between the premolar and first molar in the maxilla. The tooth was fixed with resin and a twisted wire for 1 month. Two years after transplantation, the tooth responded positively to pulp vitality tests but did not move toward the occlusal line, and dental X-ray showed a lamina dura, mineralisation of the pulp cavity, no root resorption and development.

Effect of hypoxia duration on the oxygen-dependent production of a recombinant protein, β-galactosidase, by an animal cell line, F6D2, with a hypoxia-inducible enhancer

Expression of specific genes is a strategy of animal cells for adaptation to oxygen deficiency and the mechanism underlying the hypoxic activation of gene expression may be useful for efficient production of recombinant proteins by animal cells, because oxygen is a limiting factor in animal cell cultures. We prepared an animal cell line harboring the plasmid in which expression of a reporter gene, β-galactosidase, is controlled by an enhancer responsible for the hypoxic activation of gene transcription. The purpose of this paper is to understand this hypoxic production of recombinant proteins quantitatively by a mathematical model originally developed based on the following hypotheses; 1 lacZ (the reporter gene) is transcribed after HIF-1 protein complex is bound to the hypoxic enhancer, 2. β-galactosidase synthesis rate is limited at the transcription of lacZ, 3. HIF-1 is an inactive form under a normal oxygen concentration, 4. Oxygen works as a repressor in the synthesis of HIF-1 protein, 5. Both β-galactosidase and HIF-1 are decomposed according to the first order reaction. The effects of hypoxic duration as well as oxygen concentration on the β-galactosidase production were successfully predicated by the model.

In vitro neuroprotective action of recombinant rat erythropoietin produced by astrocyte cell lines and comparative studies with erythropoietin produced by Chinese hamster ovary cells

In the central nervous system, astrocytes produce erythropoietin (Epo) and neurons express its receptor. To examine whether or not the brain Epo protects the in vitro cultured neurons from glutamate-induced cell death, we established rat astrocyte cell lines containing the plasmid for production of recombinant rat Epo. Epo partially purified from the culture medium showed a neuroprotective effect similar to that of rat Epo produced by Chinese hamster ovary (CHO) cells. Comparison was made in some other properties between Epo produced by these astrocyte cell lines and that by CHO cells.

Erythropoietin enhancer stimulates production of a recombinant protein by Chinese hamster ovary (CHO) cells under hypoxic condition

Oxygen is a limiting nutrient in animal cell culture and its supply is still worthy of improvement for production of useful proteins with a high efficiency. From a different point of view, development of the system by which a high productivity can be maintained even under hypoxic condition as well as under normoxic condition may be important. A number of hypoxia-inducible genes have been found in eucaryotic cells and the induction in most cases, if not all, is due to hypoxic activation of the gene transcription. Transcription of erythropoietin gene is highly hypoxia-inducible and the induction is achieved by binding of a protein, which is widely distributed in animal cells, to a short DNA stretch (erythropoietin enhancer) in the 3' flanking region of erythropoietin gene. Using a hepatoma cell line (Hep3B) that produces the endogenous erythropoietin in an oxygen-dependent manner and Chinese hamster ovary cells that have been widely used for production of recombinant proteins, we show that, under hypoxic condition, the erythropoietin enhancer can activate not only the promoter of erythropoietin gene but also promoters of cytomegalovirus early genes and eucaryotic polypeptide chain elongation factor gene, both of which are very active in animal cells under normoxic condition.

Correlation of circulating dehydroepiandrosterone with activated protein C generation and carotid intima-media thickness in male patients with type 2 diabetes

AIMS

Dehydroepiandrosterone exerts a protective effect against cardiovascular diseases. However, the relationship of dehydroepiandrosterone with the anticoagulant factor activated protein C, generated by the thrombin-thrombomodulin complex on vascular endothelial cells, remains unknown. This study aimed at studying the relationship between dehydroepiandrosterone and activated protein C generation in patients with Type 2 diabetes.

METHODS

Sixty-two male patients with Type 2 diabetes were enrolled in this study. Data obtained from 40 healthy male subjects were used as controls. The plasma levels of dehydroepiandrosterone, the activated protein C-protein C inhibitor complex, high-sensitivity C-reactive protein and monocyte chemoattractant protein-1 were measured by enzyme immunoassays. Carotid intima-media thickness was measured by ultrasonography.

RESULTS

The plasma levels of dehydroepiandrosterone (5.15 ± 2.81 vs. 3.76 ± 2.16 ng/ml; P < 0.005) and the activated protein C-protein C inhibitor complex (1.90 ± 1.07 vs. 1.02 ± 0.51 ng/ml; P < 0.001) were significantly lower in patients with diabetes than in normal subjects. Univariate analysis showed a significant correlation of the plasma level of dehydroepiandrosterone with that of the activated protein C-protein C inhibitor complex (r = 0.48, P < 0.001), high-sensitivity C-reactive protein (r = -0.30, P < 0.05) and with the mean intima-media thickness (r = -0.28, P < 0.05) in patients with diabetes. Stepwise multiple regression analysis showed that the plasma level of dehydroepiandrosterone is significantly correlated with the plasma levels of the activated protein C-protein C inhibitor complex (F = 18.06) and high-sensitivity C-reactive protein (F = 4.94). There was no correlation between the plasma levels of dehydroepiandrosterone and monocyte chemoattractant protein-1.

CONCLUSIONS

These results suggest that lower circulating levels of dehydroepiandrosterone are associated with decreased activated protein C generation and higher intima-media thickness in patients with Type 2 diabetes.

In vitro neuroprotective action of recombinant rat erythropoietin produced by astrocyte cell lines and comparative studies with erythropoietin produced by Chinese hamster ovary cells

In the central nervous system, astrocytes produce erythropoietin (Epo) and neurons express its receptor. To examine whether or not the brain Epo protects the in vitro cultured neurons from glutamate-induced cell death, we established rat astrocyte cell lines containing the plasmid for production of recombinant rat Epo. Epo partially purified from the culture medium showed a neuroprotective effect similar to that of rat Epo produced by Chinese hamster ovary (CHO) cells. Comparison was made in some other properties between Epo produced by these astrocyte cell lines and that by CHO cells. Digestion of Epo with glycosidases indicated that there was a little difference in glycosylation of Epo produced by two types of the cells.