A histopathological mapping study of the urinary bladder tumors induced by N-butyl-N-(4-hydroxybutyl)nitrosamine in dogs

Bladder tumors were induced by N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) in five Beagles and four mongrel dogs. The tumors were observed for long periods and the tumor progression was traced using histopathological mapping. The results indicated (1) that low-dose BBN over a long period induced multiple low-grade (G1-2) and low-stage (pTa-1) papillary tumors, resembling superficial bladder cancer in humans; (2) that high-dose BBN over a short period induced high-grade (G2-3) and high-stage (pT3b) nonpapillary tumors and carcinoma in situ (CIS) resembling invasive cancer and CIS in humans; (3) that beagle dogs required longer periods and higher total doses of BBN as compared with mongrel dogs; (4) that the tumors induced by low-dose BBN in beagles were observed without BBN as long as the animals lived, and neither increasing numbers of tumors nor malignant features such as deep infiltration and metastasis was observed; and (5) that low-dose BBN seems to induce mild dysplasia, which is followed by Brunn's nest-like proliferation in the lamina propria and nodular change, eventually leading to the development of papillary noninvasive transitional cell carcinoma (TCC); and that high-dose BBN seems to induce severe dysplasia which leads to CIS and nonpapillary invasive TCC. These results may contribute to clarifying the natural history of human bladder cancer.

Complete genome structure of the unicellular cyanobacterium Synechocystis sp. PCC6803

Cyanobacteria are photoautotrophic organisms capable of oxygen-producing photosynthesis similar to that in eukaryotic algae and plants, and because of this, they have been used as model organisms for the study of the mechanism and regulation of oxygen-producing photosynthesis. To understand the entire genetic system in cyanobacteria, the nucleotide sequence of the entire genome of the unicellular cyanobacterium Synechocystis sp. PCC6803 has been determined. The total length of the circular genome is 3,573,470 bp, with a GC content of 47.7%. A total of 3,168 potential protein coding genes were assigned. Of these, 145 (4.6%) were identical to reported genes, and 1,259 (39.6%) and 342 (10.8%) showed similarity to reported and hypothetical genes, respectively. The remaining 1,422 (45.0%) showed no apparent similarity to any genes registered in the databases. Classification of the genes by their biological function and comparison of the gene complement with those of other organisms have revealed a variety of features of the genetic information characteristic of a photoautotrophic organism. The sequence data, as well as other information on the Synechocystis genome, is presented in CyanoBase on WWW [http:/(/)www.kazusa.or.jp/cyano/].

Effects of different absorption enhancers on the permeation of ebiratide, an ACTH analogue, across intestinal membranes

The permeation of ebiratide (H-Met(O2)-Glu-His-Phe-D-Lys-Phe-NH(CH2)8NH2), a novel ACTH analogue, across the intestinal mucosae has been examined by use of isolated intestinal membranes from rats in a modified Ussing chamber. Regional differences were observed in the permeation of ebiratide across intestinal membranes; the order of membrane permeability was jejunum > ileum > duodenum > colon. Overall, the permeation of ebiratide was relatively poor. The effects of various absorption enhancers were examined to increase the intestinal permeability to ebiratide. Sodium glycocholate and sodium caprate had no significant enhancing effect on the permeability of the jejunal membrane, but significantly enhanced the permeation of ebiratide through the colonic membrane. On the other hand, N-dodecyl-beta-D-maltopyramoside (LM) significantly enhanced the permeation of ebiratide through both jejunal and colonic membranes. In general, the absorption-enhancing effects of these agents were more predominant in the colon than in the jejunum. Membrane damage by the absorption enhancers was evaluated by measuring the amount of protein released from the intestinal membrane. It was found that all the absorption enhancers slightly increased the amount of protein released, but that the amounts of protein released in the presence of these enhancers were much less than in the presence of ethylenediaminetetraacetic acid (EDTA), used as a positive control. These findings suggest that the absorption enhancers, especially LM might be useful adjuvants for improving the intestinal absorption of peptide and protein drugs, including ebiratide.

Osteoblastic phenotype expression on the surface of hydroxyapatite ceramics

To analyze the bone-bonding property of hydroxyapatite ceramics (HA), composites of rat marrow cells and porous HA were implanted subcutaneously and harvested at 3 to 4 weeks postimplantation. De novo bone formation was observed primarily on the HA surface without fibrous tissue interposition. The HA/tissue interface was analyzed by the observations of thin undecalcified histological sections and fractured surfaces of the implants. The observations were done with a light microscope and a scanning electron microscope (SEM) connected to an energy dispersive spectrometer. The interfacial analyses showed the appearance of osteoblastic cells on the HA surface and that the cells had initiated partially mineralized bone (osteoid) formation directly onto the surface. The osteoid matured into fully mineralized bone, resulting in firm bone bonding to the HA surface. Characterization of osteoblastic cells on the surface was done by determining levels of protein and gene expression of bone Gla protein (BGP, a.k.a. Osteocalcin), i.e., immunohistochemistry and in situ hybridization, respectively. The existence of BGP and mRNA in the cytoplasmic area of the cells confirmed that active osteoblast apposition fabricated primary bone on the HA surface. All of these results indicate the importance of the HA surface in supporting osteoblastic differentiation of marrow stromal stem cells, which leads to firm bone bonding.

Osteoblastic phenotype expression on the surface of hydroxyapatite ceramics

To analyze the bone-bonding property of hydroxyapatite ceramics (HA), composites of rat marrow cells and porous HA were implanted subcutaneously and harvested at 3 to 4 weeks postimplantation. De novo bone formation was observed primarily on the HA surface without fibrous tissue interposition. The HA/tissue interface was analyzed by the observations of thin undecalcified histological sections and fractured surfaces of the implants. The observations were done with a light microscope and a scanning electron microscope (SEM) connected to an energy dispersive spectrometer. The interfacial analyses showed the appearance of osteoblastic cells on the HA surface and that the cells had initiated partially mineralized bone (osteoid) formation directly onto the surface. The osteoid matured into fully mineralized bone, resulting in firm bone bonding to the HA surface. Characterization of osteoblastic cells on the surface was done by determining levels of protein and gene expression of bone Gla protein (BGP, a.k.a. Osteocalcin), i.e., immunohistochemistry and in situ hybridization, respectively. The existence of BGP and mRNA in the cytoplasmic area of the cells confirmed that active osteoblast apposition fabricated primary bone on the HA surface. All of these results indicate the importance of the HA surface in supporting osteoblastic differentiation of marrow stromal stem cells, which leads to firm bone bonding.

Identification and nitrogen regulation of the cyanase gene from the cyanobacteria Synechocystis sp. strain PCC 6803 and Synechococcus sp. strain PCC 7942

An open reading frame (slr0899) on the genome of Synechocystis sp. strain PCC 6803 encodes a polypeptide of 149 amino acid residues, the sequence of which is 40% identical to that of cyanase from Escherichia coli. Introduction into a cyanase-deficient E. coli strain of a plasmid-borne slr0899 resulted in expression of low but significant activity of cyanase. Targeted interruption of a homolog of slr0899 from Synechococcus sp. strain PCC 7942, encoding a protein 77% identical to that encoded by slr0899, resulted in loss of cellular cyanase activity. These results indicated that slr0899 and its homolog in the strain PCC 7942 represent the cyanobacterial cyanase gene (designated cynS). While cynS of strain PCC 6803 is tightly clustered with the four putative molybdenum cofactor biosynthesis genes located downstream, cynS of strain PCC 7942 was found to be tightly clustered with the two genes located upstream, which encode proteins similar to the subunits of the cyanobacterial nitrate-nitrite transporter. In both strains, cynS was transcribed as a part of a large transcription unit and the transcription was negatively regulated by ammonium. Cyanase activity was low in ammonium-grown cells and was induced 7- to 13-fold by inhibition of ammonium fixation or by transfer of the cells to ammonium-free media. These findings indicated that cyanase is an ammonium-repressible enzyme in cyanobacteria, the expression of which is regulated at the level of transcription. Similar to other ammonium-repressible genes in cyanobacteria, expression of cynS required NtcA, a global nitrogen regulator of cyanobacteria.

Structural analysis of Arabidopsis thaliana chromosome 5. II. Sequence features of the regions of 1,044,062 bp covered by thirteen physically assigned P1 clones

A total of 13 P1 clones, each containing a marker(s) specifically mapped on chromosome 5, were isolated from a P1 library of the Arabidopsis thaliana Columbia genome, and their nucleotide sequences were determined according to the shot gun based strategy and precisely located on the physical map of chromosome 5. The total length of the sequenced regions was 1,044,062 bp. Since we have previously reported the sequence of 1,621,245 bp by analysis of 20 non-redundant P1 clones, the total length of the sequences of chromosome 5 determined so far reached 2,665,307 bp. The regions sequenced in this study were analysed by comparison with the sequences in protein and EST databases and analysis with computer programs for gene modeling; a total of 225 potential protein-coding genes and/or gene segments with known or predicted functions were identified. The positions of exons which do not exhibit similarity to known genes were also predicted by computer-aided analysis. An average density of the genes and/or gene was 1 gene/4,640 bp. Introns were identified in approximately 84% of the potential genes, and the average number and length of the introns per gene were 5.3 and 184 bp, respectively. These sequence features are essentially identical to those for the previously sequenced regions. The transcription level of the predicted genes has been roughly monitored by counting the numbers of matched Arabidopsis ESTs. The sequence data and gene information are available through the World Wide Web at http:@www.kazusa.or.jp/arabi/.

Increased expression of extracellular signal regulated kinase 1 after axotomy in the dorsal motor nucleus of the vagus nerve and the hypoglossal nucleus

The extracellular signal regulated kinases (Erks) cascade is a major signalling system by which cells transduce extracellular signals into intracellular responses. To obtain information about the role of Erks in retrograde neuronal reaction, we investigated the changes of Erk 1 and Erk 2 with in situ hybridization and immunohistochemical study in the dorsal motor nucleus of vagus nerve, which shows degenerative changes, and the hypoglossal nucleus, which shows regenerative changes, of adult rats after axotomy. The expression of mRNA and protein of Erk 1 increased between 7 and 28 days after axotomy both in the vagal and hypoglossal nuclei, however, there was no remarkable change in those of Erk 2. The increased expression of Erk 1 is common to both regenerative hypoglossal and degenerative vagal neurons. These findings indicate that Erk 1 is closely related with the retrograde neuronal reaction but whether neurons are destined to survive or die depends on some other factors.

Successful treatment of a patient with Graves' disease on hemodialysis complicated by antithyroid drug-induced granulocytopenia and angina pectoris

We report here a patient with recurrent Graves' disease on hemodialysis. She also suffered from angina pectoris, which was probably a manifestation of Graves' disease due to the increased oxygen demands in the presence of fixed coronary lesions. Although antithyroid drugs induced mild granulocytopenia, propylthiouracil (PTU) or methimazole (MMI) was not discontinued during the administration of granulocyte colony-stimulating factor (G-CSF). The patient received sodium iodine-131 therapy, and became euthyroid with no chest pain. To our knowledge, this is the first case that illustrated the usefulness of G-CSF for antithyroid drug-induced granulocytopenia prior to thyroid ablation for Graves' disease complicated with chronic renal failure and angina pectoris.

Coexistence of an autonomously functioning thyroid nodule in a patient with Graves' disease: an unusual presentation of Marine-Lenhart syndrome

A 44-year-old woman developed hyperthyroidism due to the coexistence of Graves' disease and an autonomously functioning thyroid nodule (AFTN). Anti-thyrotropin receptor antibody (TRAb) was strongly positive (83.2%), and a thyroid scan initially showed diffuse uptake of Tc-99m pertechnatate in both lobes and further increased uptake in accordance with the right lobe nodule. The nodule in the right lobe was histologically diagnosed as thyroid follicular adenoma. After she was maintained in a euthyroid state by treatment with Methymazole (MMI), thyroid uptake of Tc-99m in the nodule became lower and was slightly suppressed by T3 administrations probably due to its dependence on TSH. Subtotal thyroidectomy was performed and she subsequently became euthyroid with negative TBII activity. It is concluded that she had a coexisting functioning nodule with Graves' disease (Marine-Lenhart syndrome) and that the nodule changed from hot to cool along with the anti-thyroid treatment, unlike usual cases of this syndrome showing a cold nodule on the initial imaging under the hyperthyroid state. Repeated Tc-99m pertechnatate thyroid scans were helpful in evaluating the reaction of MMI and TSH in both lesions separately in the present case.

Structural analysis of Arabidopsis thaliana chromosome 5. I. Sequence features of the 1.6 Mb regions covered by twenty physically assigned P1 clones

A total of 20 P1 clones with an average insert size of 80 kb and each containing a marker(s) specifically mapped on chromosome 5 were isolated from a P1 library of the Arabidopsis thaliana genome, and their nucleotide sequences were determined according to a shotgun-based strategy and precisely located on the physical map of chromosome 5 separately constructed. The total length of the sequenced regions were summed up to 1,621,245 bp. By comparison with the sequences in protein and EST databases and analysis with computer programs for gene modeling, a total of 347 potential protein-coding genes and/or gene segments with known or predicted functions were identified. The positions of exons which do not exhibit any similarity to known genes were also predicted. An average density of the genes and/or gene segments assigned so far as 1 gene/4,672 bp. Introns were identified in approximately 78% of the potential genes, and the average number and length of the introns per gene were 3.7 and 161 bp. The transcription level of the predicted genes was roughly monitored by counting the numbers of identified Arabidopsis ESTs. The sequence data and gene information are available through the World Wide Web at http:/(/)www.kazusa.or.jp/arabi/.

Anti-tumor mechanisms of 3'-ethynyluridine and 3'-ethynylcytidine as RNA synthesis inhibitors: development and characterization of 3'-ethynyluridine-resistant cells

To discover the mechanisms of anti-tumor action of 3'-ethynyluridine (EUrd) and 3'-ethynylcytidine (ECyd), we established an EUrd-resistant variant from human fibrosarcoma HT-1080 cells. The cells were cross-resistant to ECyd. Uridine/cytidine kinase activity diminished in the resistant cells. The incorporation of EUrd and ECyd into the RNA fraction in the resistant cells was less than that of the parental cells. EUrd-triphosphate inhibited RNA synthesis by human RNA polymerase II. The results led us to conclude that EUrd and ECyd are phosphorylated by uridine/cytidine kinase to 5'-triphosphates, and that their triphosphates might inhibit RNA polymerase.

[A case of bronchial stenosis due to postoperative inflammation treated with expandable metallic stent]

We presented a 61-year-old man who had undergone a left sleeve upper resection because of a squamous cell carcinoma of the upper lobe of the left lung. At 5 weeks after the operation, the anastomosis between the left main bronchus and the left lower bronchus became stenotic, therefore pneumonitis occurred below the anastomosis. Because of the inflammatory granulo stenosis for short time, we used an expandable metallic stent to save a residual lung function of the operated side. The anastomosis between the left main bronchus and the left lower bronchus was kept open satisfactorily, and in the late postoperative periods the residual lung function recovered until the levels of predicted residual lung function.

In vitro bone formation by rat marrow cell culture

Fresh marrow cells were obtained from the femora Fischer rats and cultured in a medium containing 15% fetal calf serum (FCS) to leach confluent. After trypsinization, cells were subcultured at a cell density of 100 x 10(3)/35 mm well in the presence of FCS, 10 mM beta-glycerophosphate, 82 micrograms/mL ascorbic acid phosphate, and 10(-8)M dexamethasone (Dex). Osteoblastic cells and microscopic mineralized nodules began to appear at about 1 week after the subculture, and at 2 weeks many macroscopic nodules that showed high alkaline phosphatase activity (ALP) and appearance of bone Gla protein (BGP) mRNA were evident. As demonstrated by in situ hybridization, the mRNA was manifested by cuboid-shaped cells (osteoblastic cells). X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) showed the mineralization of fine crystals of hydroxyapatite comparable to natural rat bone mineral. In contrast to these findings, subculture done under the same conditions except for the lack of Dex did not show mineralized nodules, nor did they show the osteoblastic phenotype expression. These analyses indicate that Dex-induced mineralization using rat bone marrow cell culture is an in vitro counterpart of bone formed in vivo. Such a culture is useful for investigating materials/ osteogenic cells interactions.

In vitro bone formation by rat marrow cell culture

Fresh marrow cells were obtained from the femora Fischer rats and cultured in a medium containing 15% fetal calf serum (FCS) to leach confluent. After trypsinization, cells were subcultured at a cell density of 100 x 10(3)/35 mm well in the presence of FCS, 10 mM beta-glycerophosphate, 82 micrograms/mL ascorbic acid phosphate, and 10(-8)M dexamethasone (Dex). Osteoblastic cells and microscopic mineralized nodules began to appear at about 1 week after the subculture, and at 2 weeks many macroscopic nodules that showed high alkaline phosphatase activity (ALP) and appearance of bone Gla protein (BGP) mRNA were evident. As demonstrated by in situ hybridization, the mRNA was manifested by cuboid-shaped cells (osteoblastic cells). X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) showed the mineralization of fine crystals of hydroxyapatite comparable to natural rat bone mineral. In contrast to these findings, subculture done under the same conditions except for the lack of Dex did not show mineralized nodules, nor did they show the osteoblastic phenotype expression. These analyses indicate that Dex-induced mineralization using rat bone marrow cell culture is an in vitro counterpart of bone formed in vivo. Such a culture is useful for investigating materials/ osteogenic cells interactions.

[A comparative study of the effects of granisetron alone and a combination of granisetron plus steroids on CDDP-based combination chemotherapy-induced emesis--outcomes of a multicenter randomized comparative study using the central registration method. Nara Medical University Kytril Study Group]

The present investigation was conducted to examine the effects of granisetron alone and a combination of granisetron plus steroids on CDDP-based combination chemotherapy-induced emesis by multi-institutional randomized comparative trial using a central registration method. A total of 62 patients with urological cancer enrolled this study were randomized into two groups: granisetron (40 micrograms/kg) only group and granisetron (40 micrograms/kg) plus steroids (500 mg of methylprednisolone or 8 mg of dexamethasone) group. There were 31 patients eligible in the granisetron only group and 28 in the combination group. The same anti-emetic treatments were given in the recycling courses of chemotherapeutic regimens. Therefore, eligible patients of the second and the third cycle numbered 31 (17 in the granisetron only group, 14 in the combination group) and 21 (11 in the granisetron only group and 10 in the combination group). Significant inhibition of acute emesis in combination group was observed when compared with the granisetron only group in each cycle. Delayed emesis was also significantly inhibited in the combination group on Day 2 and 3 of the first cycle and on Day 2 of the second and third cycle. In addition, appetite loss was significantly reduced in the combination group on Day 2 and 3 of the first and second cycle. No adverse events were seen in either group. These results suggested that a combination of granisetron and steroids was useful for preventing CDDP-based combination chemotherapy-induced emesis.

[Antitumor effect and mechanism of a novel multifunctional nucleoside, 3'-ethynylnucleoside, on human cancers]

The antitumor activity of 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl) cytosine (ECyd) and 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl) uracil (EUrd), designed as a potential multifunctional antitumor nucleoside to inhibit RNA and DNA syntheses, was examined. ECyd and EUrd inhibited the growth of 47 kinds of cultured human cells in vitro and also showed strong antitumor effects on 15 human solid cancers xenografted into nude mice at a dose of 0.25 mg/kg (ECyd) or 2 mg/kg (EUrd) by intravenous administration for 10 consecutive days. The in vitro cytotoxic effect of ECyd and EUrd was prevented dose dependently by cytidine and uridine, suggesting that ECyd and EUrd may require phosphorylation by uridine/cytidine kinase for antitumor activity. ECyd and EUrd strongly inhibited RNA synthesis and slightly inhibited DNA synthesis. ECyd and EUrd have shown potent antitumor activity against human experimental solid type tumors with minimal toxic effects in vivo, suggesting that ECyd and EUrd is a promising agent with a unique mechanism of action for the treatment of cancer.

[Clinical studies on lower urinary tract injury]

A total of 61 patients with lower urinary tract injuries were treated at Nara Medical University and its affiliated hospitals, between January 1985 and June 1995. There were 9 patients with bladder injuries and 52 patients with urethral injuries. The main cause of bladder injury was a traffic accident sustained in 4 patients (44.5%) and that of urethral injury was an occupational accident sustained in 27 cases (51.9%). The major associated injuries were a bone fracture seen in 45 patients (73.8%) and an intrascrotal hematoma seen in 28 patients (45.9%). Posterior urethral injuries associated with pelvic bone fractures were classified into 3 types according to the classification reported by Colapinto et al.; 8 patients (32.0%) into Type I, 8 (32.0%) into Type II and 9 (36.0%) into Type III. Of the 25 patients with posterior urethral injuries, 8 (32.0%) underwent immediate surgical treatment, 12 (48.0%) underwent initial cystostomies and delayed surgical treatment and 5 (20.0%) received indwelling of urethral catheters. Postoperative complications of urethral injury included urethral stricture in 30 patients (57.7%), incontinence in 3 (5.8%) and impotence in 3 (5.8%). A significant relationship between the duration of cystostomy and the incidence of postoperative urethral stricture was observed in our patients. Therefore at least three weeks of cystostomy will be necessary in the management of patients with complicated urethral injuries.

ISOKINETIC STRENGTH AFTER TEARS OF THE SUPRASPINATUS TENDON

We measured the isokinetic strength of abduction, adduction, internal rotation, and external rotation in ten patients with full-thickness tears of the supraspinatus and ten with partial-thickness tears. The measurements were repeated after intra-articular or intrabursal injection of local anaesthetic.

Pain blocks produced significant increases in strength in both full and partial-thickness tears. After the block, the strength in full-thickness tears compared with the opposite side was 67% to 81% in abduction and 67% to 78% in external rotation, both significantly smaller than those on the uninvolved side (p = 0.0064, p = 0.0170). In partial-thickness tears the strength after the block ranged from 82% to 111%, with no significant differences between the involved and uninvolved sides.

The decreases in strength of 19% to 33% in abduction and 22% to 33% in external rotation after full-thickness tears appear to represent the contribution of supraspinatus to the strength of the shoulder.

Isokinetic strength after tears of the supraspinatus tendon

We measured the isokinetic strength of abduction, adduction, internal rotation, and external rotation in ten patients with full-thickness tears of the supraspinatus and ten with partial-thickness tears. The measurements were repeated after intra-articular or intrabursal injection of local anaesthetic. Pain blocks produced significant increases in strength in both full and partial-thickness tears. After the block, the strength in full-thickness tears compared with the opposite side was 67% to 81% in abduction and 67% to 78% in external rotation, both significantly smaller than those on the uninvolved side (p = 0.0064, p = 0.0170). In partial-thickness tears the strength after the block ranged from 82% to 111%, with no significant differences between the involved and uninvolved sides. The decreases in strength of 19% to 33% in abduction and 22% to 33% in external rotation after full-thickness tears appear to represent the contribution of supraspinatus to the strength of the shoulder.

Compilation of all genes encoding bacterial two-component signal transducers in the genome of the cyanobacterium, Synechocystis sp. strain PCC 6803

Bacteria have devised sophisticated signaling systems for eliciting a variety of adaptive responses to their environment, which are generally referred to as the "two-component regulatory system." The widespread occurrence of the two-component systems in both prokaryotes and eukaryotes implies that it is a powerful device for a wide variety of adaptive responses of cells to their environment. The two-component signal transducers contain one or more of three conserved and characteristic phosphotransfer signaling domains, named the "transmitter, receiver, and alternative transmitter." The recently determined entire genomic sequence of Synechocystis sp. strain PCC 6803 allowed us to compile systematically a complete list of genes encoding such two-component signal transduction proteins. The results of such an effort, made in this study, revealed that at least 80 ORFs were identified as members of the two-component signal transducers in this single species of cyanobacteria.

In vitro bone formation by rat marrow cell culture

Fresh marrow cells were obtained from the femora Fischer rats and cultured in a medium containing 15% fetal calf serum (FCS) to leach confluent. After trypsinization, cells were subcultured at a cell density of 100 x 10(3)/35 mm well in the presence of FCS, 10 mM beta-glycerophosphate, 82 micrograms/mL ascorbic acid phosphate, and 10(-8)M dexamethasone (Dex). Osteoblastic cells and microscopic mineralized nodules began to appear at about 1 week after the subculture, and at 2 weeks many macroscopic nodules that showed high alkaline phosphatase activity (ALP) and appearance of bone Gla protein (BGP) mRNA were evident. As demonstrated by in situ hybridization, the mRNA was manifested by cuboid-shaped cells (osteoblastic cells). X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) showed the mineralization of fine crystals of hydroxyapatite comparable to natural rat bone mineral. In contrast to these findings, subculture done under the same conditions except for the lack of Dex did not show mineralized nodules, nor did they show the osteoblastic phenotype expression. These analyses indicate that Dex-induced mineralization using rat bone marrow cell culture is an in vitro counterpart of bone formed in vivo. Such a culture is useful for investigating materials/ osteogenic cells interactions.