Estrogen inhibits bone resorption by directly inducing apoptosis of the bone-resorbing osteoclasts.

Estrogen deficiency causes bone loss, which can be prevented by estrogen replacement therapy. Using a recently developed technique for isolation of highly purified mammalian osteoclasts, we showed that 17 beta-estradiol (E2) was able to directly inhibit osteoclastic bone resorption. At concentrations effective for inhibiting bone resorption, E2 also directly induced osteoclast apoptosis in a dose- and time-dependent manner. ICI164,384 and tamoxifen, as pure and partial antagonists, respectively, completely or partially blocked the effect of E2 on both inhibition of osteoclastic bone resorption and induction of osteoclast apoptosis. These data suggest that the protective effects of estrogen against postmenopausal osteoporosis are mediated in part by the direct induction of apoptosis of the bone-resorbing osteoclasts by an estrogen receptor- mediated mechanism.

The polyphosphate kinase gene of Pseudomonas aeruginosa.

We have cloned and sequenced a gene encoding polyphosphate kinase (PPK) from Pseudomonas aeruginosa PAO1. The gene immediately follows the hemB gene encoding porphobilinogen synthase responsible for heme synthesis. The predicted amino acid sequence of P. aeruginosa PPK is similar to those of PPKs previously characterized except that it possesses an extra stretch of 46 amino acids at its N-terminus, which has significant similarity to the Ras-related protein ARA5 of Arabidopsis thaliana. When P. aeruginosa PPK was overproduced in Escherichia coli, ATP-dependent polyphosphate-synthesizing activity was drastically enhanced, confirming that the protein is a PPK.

The gene for an exopolyphosphatase of Pseudomonas aeruginosa.

In Pseudomonas aeriginosa, a gene, ppx, that encodes exopolyphosphatase [exopoly(P)ase; EC 3.6.1.11] of 506 amino acids (56,419 Da) was found downstream of the gene for polyphosphate kinase, ppk. Since ppx is located in the opposite direction of the ppk gene, they do not constitute an operon. The predicted amino acid sequence of PPX is 41% identical with Escherichia coli PPX. The gene product of ppx (paPPX) was overproduced in E. coli, and its activity was evaluated. Orthophosphate (Pi) is released from polyphosphate [poly(P)], the average chain lengths of which are 79 and 750, respectively. The amount of Pi released matched the amount of poly(P) lost. Thus ppx encodes an enzyme that has exopoly(P)ase activity.

Cloned infectious complementary DNA of the poliovirus Sabin 1 genome: biochemical and biological properties of the recovered virus.

A complete cDNA copy of the genome of the attenuated type 1 poliovirus vaccine (Sabin 1) strain was constructed and inserted into the EcoRI site of the plasmid pBR325. When cultured mammalian cells were transfected with this recombinant plasmid, 20 to 50 poliovirus plaques per 10 micrograms plasmid DNA were observed. Fingerprints of the RNA of the recovered virus showed no changes when compared with those of the parental virus genome, an observation indicating that the primary structure of the cloned cDNA is a reflection of authentic poliovirus RNA. The recovered virus had the same properties as those of the Sabin 1 strain in regard to antigenicity, sensitivity to temperature, and dependency on bicarbonate concentration. These results suggest that the virus obtained by DNA transfection is indistinguishable from the Sabin 1 strain. The recombinant plasmid could therefore be used as a stable repository of the virus and as inoculum for the oral polio live vaccine.

Repeat renal biopsy in children with IgA nephropathy.

Serial renal biopsy findings in 61 children with IgA nephropathy were correlated with their clinical course. At the time of the second biopsy, 23 patients showed clinical remission defined as complete disappearance of proteinuria and hematuria with normal renal function while 38 had persistent urinary abnormalities with normal renal function at the second biopsy. There were no differences between the two groups with regard to initial clinical findings and pathologic findings of the initial renal biopsy. The second biopsy of patients with clinical remission showed improvement of the glomerular changes on light microscopy, disappearance or diminution of IgA deposits in the mesangium and decrease of electron-dense deposits, whereas the second biopsy of patients with persistent urinary abnormalities showed progression of glomerular changes on light microscopy, persistence of mesangial IgA deposits and persistence of electron-dense deposits. Our study results show the importance of repeat renal biopsy in children with IgA nephropathy with persistent urinary abnormalities, as a progression of glomerular changes is common in these patients. These observations suggest that the deposition of IgA in the mesangium may be responsible for the glomerular damage in children with IgA nephropathy.

A novel ATP regeneration system using polyphosphate-AMP phosphotransferase and polyphosphate kinase.

Polyphosphate-AMP phosphotransferase (PAP) and polyphosphate kinase (PPK) were used for designing a novel ATP regeneration system, named the PAP-PPK ATP regeneration system. PAP is an enzyme that catalyzes the phospho-conversion of AMP to ADP, and PPK catalyzes ATP formation from ADP. Both enzymes use inorganic polyphosphate [poly(P)] as a phosphate donor. In the PAP-PPK ATP regeneration system, ATP was continuously synthesized from AMP by the coupling reaction of PAP and PPK using poly(P). Poly(P) is a cheap material compared to acetyl phosphate, phosphoenol pyruvate and creatine phosphate, which are phosphate donors used for conventional ATP regeneration systems. To achieve efficient synthesis of ATP from AMP, an excessive amount of poly(P) should be added to the reaction solution because both PAP and PPK consume poly(P) as a phosphate donor. Using this ATP generation reaction, we constructed the PAP-PPK ATP regeneration system with acetyl-CoA synthase and succeeded in synthesizing acetyl-CoA from CoA, acetate and AMP. Since too much poly(P) may chelate MG2+ and inhibit enzyme activity, the Mg2+ concentration was optimized to 24 mM in the presence of 30 mM poly(P) in the reaction. In this reaction, ATP was regenerated 39.8 times from AMP, and 99.5% of CoA was converted to acetyl-CoA. In addition, since the PAP-PPK ATP regeneration system can regenerate GTP from GMP, it could also be used as a GTP regeneration system.

The bond strength of a glass polyalkenoate cement to enamel and stainless steel.

An in vitro evaluation of bond strength of a glass polyalkenoate cement to human dental enamel and stainless steel is reported. Shear testing of adhesive strength was measured over time at 23 degrees C following a one minute mixing time. It was found that there is a significant difference in bond strengths between enamel and stainless steel with strength to enamel the greater. Bond strength increases with time with very low strength measured within 30 minutes from commencement of mixing.

[Development of cancer immunotherapy by a combination of biological response modifiers on the basis of their mechanism of action].

The enhancement of antitumor effects by combination of biological response modifiers (BRM) was investigated on the basis of their action mechanisms. Experimentally, significant inhibition of tumor growth by combination treatment with BRM, which eliminated immune suppressive mechanisms and in turn enhanced immune responses, was observed. Furthermore, inhibition of tumor growth was observed under conditions of uniform biorhythm in mice and the effect of modification of biorhythm was enhanced by combination with BRM. Clinically, combination treatment of plasma exchange and LAK-cell adoptive immunotherapy was discussed.

[The role of the spleen in immunosuppression and the effects of splenectomy on prognosis in gastric cancer patients].

To elucidate the role of the spleen on the immunosuppression in gastric cancer patients, mechanism of the induction of suppressor cells in the spleen was investigated. Studies of tissue distribution of T cells using monoclonal antibodies revealed that spleen contained much higher proportion of OKT8 reactive T cells as compared with those in regional lymphnodes without metastasis. Lymphocytes released from the spleen during perfusion were taken to be representative of recirculating lymphocytes. Suppressor precursor cells were found to exist predominantly in perfusate from the spleen, while spontaneously activated suppressor cells were in the residual lymphocytes in the spleen after perfusion. Culture supernatants from splenic adherent cells induced suppressor cell activities as well as sera from splenic venous blood. These results suggest that suppressor precursor cells which could be mobilized slowly was more comparable to splenic lymphocytes and might be matured by factors released from splenic adherent cells, partly moving into peripheral blood. Furthermore, the effect of splenectomy on the prognosis of gastric cancer patients was investigated in randomized controlled trial. The patients who underwent total gastrectomy and had main location of the tumor on lesser curvature region were divided into two groups at random; splenectomy (+) and splenectomy (-) groups. A suggestive prolongation of survival time was observed in splenectomy (+) group. Thus, spleen seem to contribute to the immunosuppression in gastric cancer patients and splenectomy may lead to better prognosis.

[Local immunotherapy for cancer].

As for the non-specific cancer immunotherapy concerned, the effect is limited and local use of immunopotentiators which could collect effector cells around tumor tissues might be the best way of cancer immunotherapy. Intratumoral or intraperitoneal administration of large-dose of OK-432 (100 KE) has been investigated since many years with favorable results. Side effects were minimum with a few days continuing slight fever elevation. From the immunohistological examinations using monoclonal antibodies, participation of killer T cells and NK cells was confirmed after intratumoral administration of large-dose OK-432. On the other hand, after intraperitoneal administration of OK-432, neutrophil leucocytes appeared at first on the 2nd to 4th day and they were followed by lymphocytes on the 4th to 5th day and finally appeared lot of macrophages on the 6th and later days. From the results of in vitro and in vivo experiments, these macrophages seemed to play the leading role in the cytostatic activities after intraperitoneal OK-432 administration. As for the fear of introducing suppressor cells after large-dose OK-432 administration, detailed studies on suppressor activities before and after operation for gastric cancer patients revealed no particular increase of suppressor cell activities after intratumoral and intraperitoneal administration of 100 KE OK-432 as compared with curative resection cases with no OK-432 administration.

The Begg technique in Japan, 1961-1979.

This article not only describes how the Begg technique has been assimilated in Japan but also disclosed improvements that were made to cope with Japanese malocclusions without collapsing the philosophy of the Begg technique's pioneers. Three cases of mandibular protrusion and bimaxillary protrusion, which account for about 50 percent of orthodontic patients in Japan, demonstrate how the Begg technique was applied. Also, some analysis is made of the various problems that are presently being imposed on the Begg technique.

[Study on the formation of fluorapatite with freeze-drying silicahydro gel method].

Resultant products and gel substance, formed with silicahydro gel method as well as with freeze-drying silicahydro gel method by use of tray, were compared and examined to materialize clinical application of gel method easily and the following results were obtained: 1. Evaluation of gel substance in control group gel (silicahydro gel) and in experimental group gel (gel prepared by the addition of deionized water to freeze-drying silicahydro gel) As the results of measuring the estimation of F- by ion chromatography and pH value, no clear-cut distinction between control group gel and experimental group gel was recognized, however, it was implied by naked-eye observations and through scanning electron microscope with the passage of time that experimental group gel had been inferior to control group gel. 2. Evaluation of resultant products in control group gel (resultant products formed with silicahydro gel method) and in experimental group gel (resultant products formed with freeze-drying silicahydro gel method) Naked-eye observations of reacting progress, the pH measurements, the calculation of Ca/P ratio, qualitative analyses by X-ray diffraction (reference; the measurements of crystallite size, lattice imperfection and lattice constant) and composition analyses by infrared absorption spectrum were carried out and as the results, resultant products in control group gel proved to be more favorable than those in experimental group gel. From the foregoing outcomes, it was suggested that fluorapatite of favorable crystallinity had been possible to be produced more with silicahydro gel method than with freeze-drying silicahydro gel method, and that further investigation inclusive of gel substance would be required in the event of clinically applying freeze-drying silicahydro gel method effectively.

[An X-ray crystallographic study on effect of acid etching method to enamel and enhancement of crystallinity of the etched enamel with gel method].

With the purpose of studying the influence of enamel acid etching technique, and the effectiveness of a strengthening of tooth enamel by silicahydro gel method, the following groups were compared, analyzed and observed by the measurements of diffracted X-ray from thin layer specimens and by microarea X-ray diffraction from an X-ray crystallographic point of view. Group I: non-treated tooth enamel Group II: acid-etched tooth enamel Group III: tooth enamel by application of silicahydro gel method after being acid etched. The results obtained were as follows: 1. Qualitative analyses by the measurements of diffracted X-ray from thin layer specimens 1) Ca5(PO4)3F, Ca5F (PO4)3 and Ca3(PO4)2.xH2O were detected in every group, and Ca3(PO4)2.xH2O demonstrated a high reliable value in group III. 2) In comparison with groups I and II, group III clearly revealed a peak shift toward high angle side, however, a halo peak was not recognized in every group. 3) As a result of evaluating crystallinity, crystallinity became favorable in order of group II, group I and group III. 4) A-axis lattice constant shortened in order of group II greater than group I greater than group III, and c-axis lattice constant shortened in order of group II greater than group I = group III. 2. Qualitative analyses by microarea X-ray diffraction 1) Solid solution of Ca5(PO4)3F and Ca5(PO4)3(OH) proved to exist in every group and in each microarea. 2) A halo peak appeared in group II and showed the trend of disappearance in group III, however, no peak shift was observed in all groups. From the foregoing results, the loss of the utmost enamel surface layer exhibiting high crystallinity and the lowering of crystallinity by acid etching technique were revealed from an X-ray crystallographic point of view and furthermore if silicahydro gel method was applied, it was suggested that enamel would be restored or that crystallinity would be enhanced.