Root development of rat tooth germs implanted in the tooth socket and in the subcutaneous tissue.

OBJECTIVE: This study was designed to investigate root development of a rat tooth germ implanted in a tooth socket or in a subcutaneous region. MATERIALS AND METHODS: Tooth germs of the upper left first molars in 2-week-old rats were extracted and implanted in the original tooth socket or in the subcutaneous region of the back. The upper right first molar was used as a control. The rats were fixed in weeks 1, 2, 4, 8 and 12. The root development was examined quantitatively with X-ray radiographic morphometry. The cellular activity of producing matrix proteins was assessed using in situ hybridization for type I collagen. RESULTS: Root development was observed in the implanted teeth in the tooth socket as also in the control teeth. In contrast, roots hardly developed in subcutaneously implanted teeth. Histology showed that periodontal ligaments were arranged around roots of implanted teeth in the tooth socket as around control teeth, but few periodontal ligaments were identified in the subcutaneous implantation. Dentin and cementum formed in both the implanted teeth as also in the control teeth and odontoblasts, cementoblasts and cementocytes expressed type I collagen. CONCLUSION: Tooth sockets may possess specific environments that allow root development of a tooth germ.

Characterization of dentin formed in transplanted rat molars by electron probe microanalysis.

The present study was designed to characterize dentin formed in transplanted rat molars by investigating calcium (Ca), phosphorus (P), and magnesium (Mg) concentrations using electron probe microanalysis (EPMA) as well as examining the rate of dentin matrix formation by vital staining. The unerupted immature lower right second molar in 2-week-old rats was transplanted into the upper right first molar socket. Rats were injected with oxytetracycline, calcein, and alizarin intraperitoneally at 1 day before and 1 and 2 weeks after transplantation, respectively, for vital staining. The maxillae and mandibles were fixed 3 weeks after transplantation, resected, and embedded in resin. Undemineralized sections were cut and examined by fluorescent microscopy and EPMA. The thickness of dentin formed in the first week after transplantation was significantly less than that of dentin formed in any other 1-week period in the transplanted tooth and was about one-fifth the thickness of dentin formed in control teeth. Formation of dentin recovered in the third week after transplantation. In the first week after transplantation, EPMA demonstrated a sharp increase in Mg concentration with a slight decrease in Ca concentration. Thereafter, no significant difference was identified among Ca, P, or Mg concentrations or the Ca/P ratio between transplanted and control teeth. These results suggest that disruption of the circulation and innervation by transplantation cause a temporary change in the matrix formation rate and elemental distribution of dentin, which is subsequently restored within 2 weeks after transplantation.

Enantiomeric purity determination of malic acid in apple juices by multi-beam circular dichroism detection.

A multi-beam circular dichroism (CD) detector which is easily constructed by inserting inexpensive optics into a conventional photo-diode array detector has an advantage of simultaneous detection of the absorbance and CD. The enantiomeric purity determination of malic acid in beverages was performed by this detection system. Malic acid when complexed with Cu(II) was found to have an absorbance maximum at around 750 nm. The L-malic acid-Cu(II) complex showed a positive Cotton effect in its absorbance band and its anisotropy factor (delta epsilon/epsilon) was relatively large at about 1/170. This complex was retained on a reversed-phase column with the addition of racemic 2-hydroxy-3-methylbutyric acid to the mobile phase as the ligand. A plot of the relative peak areas between the CD and the absorption (delta abs/abs) versus optical purity showed good linearity with a correlation coefficient of 0.999, and the precision expressed as the relative standard deviation of the errors from the regression line was +/-2.7% (2sigma). The accuracy of the proposed method was assessed by capillary electrophoresis. Eight commercially available juice products were analyzed using this method. Five of them were thought to be adulterated with synthetic malic acid.

[Changes in concentration of cefotetan in blood and lung tissue after intravenous administration].

Cefotetan (CTT), a newly-developed cephamycin antibiotic, has been used widely for the treatment of various infectious diseases because of its excellent antibacterial potency and dynamic transport in vivo. Although the drug transfer to almost every organ, tissue, and body fluid has been studied, only a few reports are available regarding the transfer to lung tissue. In the present study, 1 g of CTT was intravenously injected in a single dose to each of 22 patients subjected to pulmonary resection. Subsequently, its concentrations in blood and lung tissue were measured in sequence. The degree of transfer of the drug to the lung tissue was calculated to evaluate the pharmacodynamics of CTT in vivo. The following results were obtained in this analysis. 1. The T1/2(beta) of the concentration in blood was 4.18 hours, and AUC0-infinity was 478.7 micrograms.hr/ml. 2. Cmax in the lung tissue was 31.5 micrograms/g, and Tmax was 0.83 hour, and tissue concentrations decreased in parallel to blood concentrations. CTT was transferred to the lung tissue to achieve high concentrations following an intravenous administration. Since high concentrations are maintained for a long period of time, this antibiotic is expected to exert an excellent effect in the prevention and the treatment of respiratory infections.

Quantitative determination of urinary protein components of children with postural proteinuria.

Twenty-one protein components were measured in urine specimens from 12 subjects with postural proteinuria in the recumbent posture and after a period of upright lordotic posture. The lordotic posture produced an increased urinary excretion of total protein and 19 protein components, particularly of albumin, IgG globulin, and transferrin (128, 68, and 167-fold, respectively). However, 90 min after the lordotic posture, most of the protein components returned to initial values, whereas albumin, IgG globulin, and transferrin remained high. beta 2-Microglobulin, retinol binding protein, and lysozyme showed the smallest increases after the lordotic posture. These findings suggest that proteinuria occurring after the lordotic posture may be characterized by an increased glomerular permeability.

Characterization of messenger RNA for fructose 1,6-bisphosphate aldolase A isozyme of rat ascites hepatoma AH 7974 cells.

The messenger activity for fructose 1,6-bisphosphate aldolase (EC4.1.2.13) (aldolase) A isozyme has been characterized in the polysome- or the messenger RNA-directed, protein-synthesizing system using the pH 5 fraction of rat liver or wheat germ extracts, respectively. The subunit of aldolase A synthesized in vitro was detected by immunoprecipitation with anti-aldolase A antibody raised in chickens followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The synthesis of the enzyme depended on the addition of polysomes or polyadenylate-containing RNA of rat ascites hepatoma AH 7974 cells which show a complete shift of aldolase isozyme to type A, whereas polysomes of adult rat liver were inactive. The messenger activity for aldolase A was present exclusively on free polysomes but absent on membrane-bound polysomes and in the soluble supernatant fraction of AH 7974 cells. The size of aldolase A messenger RNA determined by formamide-containing sucrose density gradient centrifugation was approximately 5.8 X 10(5) daltons corresponding to 1650 nucleotides. Taking into account the number of amino acid residues in the aldolase A subunit, approximately 400 nucleotides correspond to the noncoding region of aldolase A messenger RNA.