High-resolution confocal detection of nanometric displacement by use of a 2 x 1 optical fiber coupler

A novel high-resolution confocal measurement of nanometric displacement that uses a simple 2 x 1 optical fiber coupler is presented. The basic principle is to detect interferometrically the change in the phase difference between two adjacent input fibers of the coupler that results from the nonuniform wave-front curvature of the reflected light. Measurement of subnanometer axial modulation, which permits high-resolution displacement sensing by optical means, is demonstrated.

A comparison of the Chinese 1992 and fifth-edition International Union Against Cancer staging systems for staging nasopharyngeal carcinoma

BACKGROUND

The Chinese 1992 staging system for nasopharyngeal carcinoma (NPC) has been widely adopted in mainland China since 1992. The fifth edition of the International Union Against Cancer (UICC) TNM classification defines new rules for classifying NPC. The current study compares the two in predicting NPC prognosis.

METHODS

Four hundred eleven NPC patients, most of whom had disease of undifferentiated histologic type and were treated in a constant fashion and with definitive intent with radiation therapy alone, entered this comparative study. The patients were restaged according to the rules of the fifth edition of the UICC staging manual and the Chinese 1992 staging system.

RESULTS

In the opinion of the authors, the predictive power of the Chinese 1992 T classification was superior. Conversely, the authors felt that the UICC N classification was more reasonable. The patients were categorized more evenly by the UICC stages than by the Chinese 1992 stages. The 5-year disease specific survival rates for patients in corresponding stages of both systems were almost identical despite differences in the criteria defining T and N classifications. Statistical analysis showed that the agreement rate was 72%. There were some agreement and correlation between the two staging systems.

CONCLUSIONS

Both systems are essentially similar. Each system appears to have some subtleties that could improve the outcome prediction of the other system if the two were somehow combined. However, it appeared to the authors that the UICC system was slightly better.

Combination of angiogenesis inhibitor TNP-470 with cytotoxic drugs in experimental therapy of nasopharyngeal carcinoma

This study was conducted to evaluate the effectiveness of angiogenesis inhibitor 6-O-(N-chloroacetyl-carbamoyl)-fumagillol (TNP-470. AGM-1470) in the treatment of nasopharyngeal carcinoma (NPC) alone and in combination with cytotoxic agents. Forty-two male BALB/c nude mice bearing human NPC cell line CNE-2 were randomized into 6 groups: those treated with saline solution, TNP-470, cisplatin (DDP), fluorouracil (5-FU), TNP-470 + DDP, and TNP-470 + 5-FU, respectively. In every treatment group, tumor growth was suppressed significantly. The combination of 5-FU with TNP-470 showed significant enhancement in antitumor efficacy. TNP-470 also enhanced the inhibitory effect of DDP, although not to statistical significance. All animals gained in body weight, although treatment with 5-FU caused slight, reversible diarrhea of 2 to 3 days' duration. The results showed that TNP-470 suppressed the growth of the human NPC cell line and enhanced the antitumor effect of 5-FU without increasing its toxicity. The combination of angiogenesis inhibitors with conventional cytotoxic agents is promising in the treatment of NPC.

The inhibitory effect of interleukin-10 on mouse osteoclast formation involves novel tyrosine-phosphorylated proteins

Interleukin-10 (IL-10) inhibits osteoclast (OC) formation in rat and mouse systems. However, little is known concerning the mechanism of this inhibitory effect. Using a coculture system of mouse bone marrow cells and primary osteoblastic cells (POB), we evaluated the potential target cells for IL-10 and components of the IL-10 activating pathway. In the coculture system, IL-10 treatment abolished OC differentiation in a dose-dependent manner. This inhibitory effect occurred regardless of the stage of cellular proliferation and differentiation, suggesting that IL-10 may act on a variety of genes participating in OC formation. IL-10 specifically abrogated the production of IL-6 by enriched bone marrow-derived mononuclear cells (BMM) but not by osteoblastic cells. IL-10 treatment also stimulated the binding of a protein in the BMM to an IL-10 response element, whereas no such activation was induced in osteoblastic cells. In contrast, interferon gamma (IFN-gamma), another inhibitory factor, stimulated tyrosine-phosphorylated proteins to bind to an IL-10 response element in both monocytes and osteoblastic cells. These data suggest that the BMM are the direct target of IL-10 action. Importantly, oligonucleotide-specific precipitation confirmed that IL-10 treatment strongly augmented 88, 85, and 70 kDa tyrosine-phosphorylated proteins in BMM. Taken together, these data show that IL-10 inhibits mouse OC formation by acting directly on hemopoietic OC precursor, through a novel signal transduction and activation pathway.

Elevation of serum vascular endothelial growth factor in male patients with metastatic nasopharyngeal carcinoma

BACKGROUND

Angiogenesis is essential for tumor growth and metastasis. Vascular endothelial growth factor (VEGF) is the most potent angiogenic factor identified to date. The authors investigated the correlation between the levels of serum VEGF (S-VEGF) in patients with nasopharyngeal carcinoma (NPC) and disease progression.

METHODS

The sera from 65 male patients with nonmetastatic NPC, 22 male patients with metastatic NPC, and 27 healthy male volunteers were obtained. A quantitative enzyme-linked immunosorbent assay was performed to measure the concentrations of S-VEGF in the sera.

RESULTS

The mean S-VEGF levels were 371.0 pg/mL(-1) (range, 128.5-691.1 pg/mL(-1)) for healthy controls, 375.6 pg/mL(-1) (range, 72.9-1202.5 pg/mL(-1)) for patients with nonmetastatic NPC, and 958.6 pg/mL(-1) (range, 264.4-3744.9 pg/mL(-1)) for patients with metastatic NPC. The mean S-VEGF level in patients with metastatic NPC was significantly higher than in either patients with nonmetastatic NPC (P < 0.001) or healthy controls (P < 0.001). However, there was no statistical difference between these results for healthy controls and patients with nonmetastatic NPC. At the level of 900 pg/mL(-1), S-VEGF indicated distant dissemination of NPC with a specificity of 95.4%, a sensitivity of 31.8%, a positive predictive value of 70.0%, and a negative predictive value of 80.5%. No significant differences in the levels of S-VEGF were found among various T classifications, N classifications, and clinical stages of nonmetastatic NPC.

CONCLUSIONS

The levels of S-VEGF were significantly elevated in male patients with metastatic NPC. These levels did not correlate with locoregional progression of NPC. The usefulness of detecting S-VEGF in the early diagnosis of NPC appears to be limited.

Within- and between-person variation of nutrient intakes of older people in Korea

OBJECTIVES

(i) To examine the components of variation in nutrient intakes for older Korean adults; (ii) To calculate the level of accuracy with varying degree of precision in order to achieve estimates of usual nutrient intakes.

DESIGN

Five or six 24 h recalls were made over a four month period on each individual.

SETTING

A senior school from a middle-income, urban community in Inchon, Korea.

SUBJECTS

Forty-seven males and 36 females over 60 y old with complete records for at least five dietary recalls.

RESULTS

The within-person variation of nutrient intakes (21.8-103.2%) was higher and differed more markedly by nutrients than the between-person variation (9.4-63.7%). Males (2.26-11.28) showed larger within-to-between person variance ratios than females (1.73-5.86). The variance ratios were different by nutrients for males, but no such pattern was observed for females. Depending on nutrients, 5-6 recalls over a four month period gave estimates of nutrient intakes within 30-50% of usual intakes. For most nutrients, 100-200 subjects were sufficient to obtain estimates with 10% deviation of group usual intakes. Achieving r=0.9 between observed and usual intakes required 24-54 recalls for males and 8-23 recalls for females.

CONCLUSIONS

The degree of precision achieved during assessment of older Korean adults' usual nutrient intakes changes with gender and by the type of nutrients. Achieving similar level of accuracy of the estimates, older Korean adults may require more dietary recalls than the adults in western countries.

Primary study in experimental antiangiogenic therapy of nasopharyngeal carcinoma with AGM-1470 (TNP-470)

OBJECTIVE

To evaluate the efficacy of the angiogenesis inhibitor AGM-1470 for the experimental treatment of nasopharyngeal carcinoma (NPC).

METHODS

A NPC human tumour model was built by tumour-bearing nude mice using the NPC cell line CNE-2. Twenty-one BALB/c nude mice bearing CNE-2 xenografts were randomized into a treatment group and a control group. In the treatment group, AGM-1470 was injected 30 mg/kg subcutaneously every other day; while the vehicle (three per cent ethanol solution in 0.9 per cent saline) was given to the mice in control group. Tumour volumes and animal weights were measured every third day. Autopsy was performed after 18 days of treatment. The tumour tissue as well as the murine tissues of heart, kidney, and liver in each mouse were removed for formalin fixation and routine HE staining. Pathological evaluation was performed in these tissues.

RESULTS

There was a significant difference in tumour volume between the two groups at day 9 of treatment and this increased thereafter. At day 15 of treatment, the tumour volume was 4251 +/- 559 mm3 (n = 10) in the control group versus 3122 +/- 967 mm3 (n = 11) in the AGM-1470 treated group (p = 0.004); and T:C ratio (mean tumour volume of treated/mean tumour volume of control) was 0.73, resulting in a 27 per cent decrease in tumour growth. Central necrosis and consequential shrinkage of tumours occurred in both groups at the end of experiment. Physical toxicity and histological toxicity of heart, liver, and kidney did not result from AGM-1470 therapy.

CONCLUSIONS

AGM-1470 suppresses the growth of the human NPC cell line CNE-2. Treatment by AGM-1470 has no physical nor histological toxicity. Angiogenesis inhibitors may be effective in the treatment of the local lesion of NPC.

Comparison of intravenous retention of fentanyl and lidocaine on local analgesia in propofol injection pain

BACKGROUND

With a tourniquet on arm for arresting venous blood flow, we evaluated the efficacy of intravenous (i.v.) retention of fentanyl and lidocaine in reducing the pain on i.v. propofol injection during general anesthesia.

METHODS

One hundred and twelve patients were studied. Following a venous occlusion by a tourniquet inflated to 70 mmHg, patients in Group A (n = 38) received normal saline (NS) 3 ml, while those in Group B (n = 37) and in Group C (n = 37) respectively received fentanyl 150 micrograms or 3 ml and 2% lidocaine 3 ml (60 mg). The venous retention of drug was maintained for 1 min, followed immediately by tourniquet release and propofol 100 mg i.v. injection over 20 s.

RESULTS

Both fentanyl and lidocaine treatments (Groups B and C) were significantly better than placebo (Group A) in reducing pain on propofol injection (p < 0.005). Lidocaine 60 mg was more effective than fentanyl 150 micrograms in reduction of pain associated with i.v. propofol (p < 0.001). Injection of fentanyl itself caused pain in 28% of patients as compared to 2% in the lidocaine group. Mild local skin erythema was noted in 14% of patients with fentanyl venous retention versus 0% of patients with lidocaine venous retention.

CONCLUSIONS

Intravenous retention of fentanyl 150 micrograms, although less effective than that of lidocaine (p < 0.001), showed local analgesic effect in reducing the pain on propofol injection. The hypothetic mechanisms of action were speculated.

Transcriptional activation and dimerization functions in the human vitamin D receptor

The C-terminal domain of the human vitamin D receptor (hVDR) is essential for dimerization with retinoid X receptors and for transcriptional activation. To define the dimerization domain of the hVDR, a series of internal deletion mutants of the receptor were prepared beginning within the E domain and extending through the F domain to the C terminus. These mutant receptors were tested for dimerization and transcriptional activities by means of gel shift assay and beta-galactosidase assay, respectively, in a yeast system. The dimerization domain of the hVDR was localized to two separate but adjacent regions of the receptor molecule. In these experiments, the activation domain colocalized with dimerization. To more precisely delineate a relationship between these domains, region-specific random mutagenesis was carried out to detect mutants using error-prone PCR and a functional screen strategy employed using transformed yeast. Two classes of inactive receptors were identified: one in which both transcriptional activation and dimerization were compromised and a second in which only transcriptional activation was abolished. Most of the mutations responsible for these phenotypes were single. The studies suggest a separation between dimerization and transactivation domains. We reconstituted each of these hVDR mutants in a mammalian expression vector and evaluated them individually in COS-1 cells. All VDR mutants were transcriptionally active in this cellular background in response to 1,25-dihydroxyvitamin D3 although the potency of the hormone was reduced. The latter observation coincided with the observation that each mutant was compromised to some extent in binding affinity. These data clearly demonstrate the existence of an activation domain in hVDR that is separable from the domain involved in dimerization. Factors that couple hVDR to the general transcription apparatus in yeast through the activation domain in the hVDR, however, appear to be unrelated or dissimilar to those used in COS-1 cells.

Expression of vacuolar H(+)-ATPase in osteoclasts and its role in resorption

By means of light- and electron-microscopic immunocytochemistry, we have demonstrated the expression of vacuolar H(+)-ATPase in mouse osteoclasts. In fully differentiated osteoclasts, intense immunolabeling was observed along the plasma membranes including those of ruffled borders and associated pale vesicles and vacuoles, whereas those of clear zones and basolateral cell surfaces were entirely free of immunoreaction. Specific expression of vacuolar H(+)-ATPase was also detected over polyribosomes and cisterns of the rough-surfaced endoplasmic reticulum. Multinucleated osteoclastic cells were suspended on dentine slices and cultured for 48 h in the presence or absence of either concanamycin B or bafilomycin A1, specific inhibitors of vacuolar H(+)-ATPase. Morphometric analysis of co-cultured dentine slices with backscattered electron microscopy revealed that both inhibitors strongly reduced the formation of resorption lacunae in a dose-dependent manner. These results suggest that vacuolar H(+)-ATPase is produced in the rough-surfaced endoplasmic reticulum, stored in the membrane vesicles, and transported into the ruffled border membranes of osteoclasts, and that this enzyme plays a key role in the creation of an acidic subosteoclastic microenvironment for the demineralization of co-cultured substrates.

Endothelin-1 localization in bone cells and vascular endothelial cells in rat bone marrow

Endothelin-1 (ET-1) localization in bone cells and associated vascular endothelial cells in metaphyseal bone marrow of the rat femur was examined by a biotin-streptoavidin-horseradish peroxidase method in paraffin sections and by indirect immunogold techniques in post-embedded ultrathin sections. Mouse anti-ET-1 monoclonal antibody was used as the primary antibody. In metaphyseal bone marrow, intense immunostaining was observed over osteoclasts, osteoblasts, young osteocytes, and vascular endothelial cells. But bone and cartilage matrices and chondrocytes in the proliferating zone were negative for immunoreaction. At the subcellular level, specific immunogold labeling was localized along plasma membranes and in the cytoplasm including those of ruffled borders and clear zones of osteoclasts. Some colloidal gold particles were also detectable within pale vacuoles of osteoclasts. Immunoreactivity was also found along the plasma membranes, cisterns of rough-surfaced endoplasmic reticulum, mitochondria, and cytoplasmic matrices of osteoblasts, but was less intense than that of osteoclasts. In endothelial cells of blood capillaries in close proximity to bone cells, intense immunolabeling occurred over the cytoplasm. None of the cases examined showed accumulation of immunogold particles in the secretion granules of these cells.

The biological roles of the third component of complement in osteoclast formation

We previously reported that 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] tissue-specifically stimulated the production of the third component of complement (C3) in bone in vitro and in vivo. In the present study, we examined the possible roles of C3 in bone using bone marrow cultures with antibodies against C3 and C3 receptors (Mac 1, 8C12, and 7G6) and the purified mouse C3 protein. The C3 protein produced preferentially by stromal cells in response to 1 alpha,25-(OH)2D3 was distributed in macrophage-like mononuclear cells and small cells with few nuclei. Adding anti-C3 antibody together with 1 alpha,25-(OH)2D3 to bone marrow cultures greatly inhibited not only the appearance of tartrate-resistant acid phosphatase (TRAP)-positive mononuclear and multinucleated cells, but also the growth of macrophage-like mononuclear cells and stromal cells. The inhibitory effect of anti-C3 antibody on osteoclast-like cell formation was most prominent when it was added between days 2-4 of the 6-day culture period, which corresponded to the late proliferative phase and the early differentiation phase of osteoclast development. Adding anti-C3 receptor antibodies also inhibited osteoclast-like cell formation induced by 1 alpha,25-(OH)2D3. When C3 receptors were detected by the binding of C3-coated sheep red blood cells or immunostaining, the localization of C3 receptor-positive cells coincided exactly with that of C3 protein-positive cells. C3 receptors were expressed mainly in macrophage-like mononuclear cells, TRAP-positive mononuclear cells, and TRAP-positive small cells with few nuclei. TRAP-positive large cells with many nuclei were totally negative for C3 receptors. When macrophage-colony-stimulating factor (M-CSF), the purified C3 protein, and 1 alpha,25-(OH)2D3 were added to bone marrow methylcellulose cultures, separately or in combination, M-CSF-dependent colony formation was strikingly inhibited by 1 alpha,25-(OH)2D3, but the inhibition was prevented by simultaneously adding C3. These results provide additional evidence that osteoclast progenitors are indeed cells of the monocyte-macrophage lineage. It is likely that the C3 produced by stromal cells in response to 1 alpha,25-(OH)2D3 is somehow involved in osteoclast development by potentiating M-CSF-dependent proliferation of bone marrow cells and induction of osteoclast differentiation.

Localization of endothelin-1 in the osteoclast

Endothelin-1 (ET-1) localization in osteoclasts in the metaphyseal bone marrow of the femur was examined by indirect immunogold techniques in post-embedded ultrathin sections. Mouse anti-ET-1 antibody and anti-mouse IgG conjugated with colloidal gold particles were used as the primary and secondary antibodies, respectively. Specific immunolabeling was localized along the plasma membranes, the cytoplasm including those of ruffled borders and clear zones, and pale vacuoles of osteoclasts. In addition, intense immunolabeling was present over the cytoplasm of vascular endothelial cells in close proximity to osteoclasts. These results suggest that osteoclasts are target cells for ET-1.

1 alpha,25-dihydroxyvitamin D3 regulates in vivo production of the third component of complement (C3) in bone

We previously reported that 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] specifically stimulates production of the third component of complement (C3) by murine osteoblastic cells and marrow-derived stromal cells (ST2) in vitro. In the present study we examined tissue-specific production of C3 in vivo in vitamin D-deficient mice, some of which received supplemental 1 alpha,25-(OH)2D3. Western blot analysis indicated that the C3 protein band in bone was undetectable in vitamin D-deficient mice, but became distinct 48 h after 1 alpha,25-(OH)2D3 administration. The mRNA expression of C3 in bone was also undetectable in vitamin D-deficient mice and appeared as early as 24 h after 1 alpha,25-(OH)2D3 administration. mRNA expression apparently preceded the appearance of C3 protein. In contrast, there was no significant difference in the expression of hepatic C3 mRNA among normal mice fed laboratory chow and vitamin D-deficient mice with and without 1 alpha,25-(OH)2D3 administration. The serum concentration of C3 in vitamin D-deficient mice was almost identical to that in normal mice and was unchanged after 1 alpha,25-(OH)2D3 administration. 1 alpha,25-(OH)2D3 receptor (VDR) mRNAs were detected in the kidney and intestine, whereas no appreciable mRNA expression of VDR occurred in the liver. Osteopontin mRNA was expressed in response to 1 alpha,25-(OH)2D3 in the kidney, but not in the intestine. Immunohistochemical studies showed that in normal mice, the C3 protein was located mainly in the periosteal regions of calvaria and on the surfaces of bone trabeculae in the tibial metaphyses. These results demonstrate that 1 alpha,25-(OH)2D3 tissue-specifically regulates in vivo production of C3 in bone. The production of bone C3 cannot be attributed to the presence of VDR alone, and we speculate that other tissue-specific factors are required.

Leukemia inhibitory factor/differentiation-stimulating factor (LIF/D-factor): regulation of its production and possible roles in bone metabolism

Leukemia inhibitory factor/differentiation-stimulating factor (LIF/D-factor), expression of its mRNA, and possible roles in bone metabolism were studied in murine primary and clonal osteoblast-like cells. Local bone-resorbing factors such as IL-1, TNF alpha, and LPS strongly induced expression of LIF/D-factor mRNA in both clonal MC3T3-E1 cells and primary osteoblast-like cells. Neither parathyroid hormone nor 1 alpha,25-dihydroxyvitamin D3 stimulated expression of LIF/D-factor mRNA. LIF/D-factor per se did not stimulate expression of its own mRNA. Appreciable amounts of LIF/D-factor were detected in synovial fluids from rheumatoid arthritis (RA) patients but not in those with osteoarthritis (OA). Simultaneous treatment with LIF/D-factor, IL-1, and IL-6 at the concentrations found in synovial fluids from RA patients greatly enhanced bone resorption, though these cytokines did not stimulate bone resorption when separately applied. This suggests that LIF/D-factor produced by osteoblasts is in concert with other bone-resorbing cytokines such as IL-1 and IL-6 involved in the bone resorption seen in the joints of RA patients. LIF/D-factor specifically bound to MC3T3-E1 cells with an apparent dissociation constant of 161 pM and 1,100 binding sites/cell. LIF/D-factor dose-dependently suppressed incorporation of [3H]thymidine into MC3T3-E1 cells. In addition, it potentiated the alkaline phosphatase activity induced by retinoic acid, though LIF/D-factor alone had no effect on enzyme activity. These results suggest that LIF/D-factor is involved in not only osteoclastic bone resorption but also osteoblast differentiation in conjugation with other osteotropic factors.

Tissue-specific production of the third component of complement(C3) by vitamin D in bone

The third component of complement (C3) is a protein produced by osteoblastic cells in response to 1 alpha,25(OH)2D3. The bone C3 appears to be involved in differentiation of bone marrow cells into osteoclasts in concert with other vitamin D-dependent factors. Further studies are needed to understand the precise role of C3 in bone.

Transcriptional regulation of the production of the third component of complement (C3) by 1 alpha,25-dihydroxyvitamin D3 in mouse marrow-derived stromal cells (ST2) and primary osteoblastic cells

We have purified a 190-kDa protein produced by mouse marrow-derived stromal cells (ST2) in response to 1 alpha,25-dihydroxyvitamin D3 [1 alpha,25-(OH)2D3] and unequivocally identified it as mouse complement C3 (C3). In this study we examined the regulation by 1 alpha,25-(OH)2D3 of C3 production in ST2 cells at both the transcriptional and translational levels. 1 alpha,25-(OH)2D3 greatly increased the protein production of C3 at 24 h, and it attained a maximum at 72 h. C3 mRNA stimulation by 1 alpha,25-(OH)2D3 was initiated at 12 h and reached a maximum at 48 h. 1 alpha,25-(OH)2D3 increased the expression of C3 mRNA dose-dependently, ranging from 10(-10)-10(-8) M. The increase in the C3 production in response to 1 alpha,25-(OH)2D3 appeared to occur at a transcriptional level, since actinomycin-D completely inhibited both mRNA expression and protein production of C3 induced by 1 alpha,25-(OH)2D3. Besides 1 alpha,25-(OH)2D3, local bone-resorbing agents, such as interleukin-1 alpha, tumor necrosis factor-alpha, and lipopolysaccharides, also stimulated the expression of C3 mRNA, not only in ST2 cells, but also in primary osteoblastic cells. C3 production by hepatocytes occurred regardless of the presence or absence of 1 alpha,25-(OH)2D3. These results clearly indicate that 1 alpha,25-(OH)2D3 tissue-specifically regulates the synthesis of C3 in bone. Bone C3 may play an important role in bone metabolism.

Granulocyte-macrophage colony-stimulating factor is a major macrophage fusion factor present in conditioned medium of concanavalin A-stimulated spleen cell cultures

In 1983, we reported that the conditioned medium (CM) of spleen cell cultures treated with Con A greatly induced fusion of mouse alveolar macrophages within 2 to 3 days at a very high rate of more than 80% (Proc. Natl. Acad. Sci. USA 80:5583, 1983). In the course of examining macrophage fusion factors (MFF) present in Con A-CM, we found that IL-4 induced fusion of alveolar macrophages with a time course similar to that induced by Con A-CM. However, the maximal fusion rate induced by IL-4 (4 ng/ml) was about 35%. Furthermore, the fusion induced by Con A-CM was blocked only partially by adding IL-4 antibody, indicating that there are unknown MFF other than in Con A-CM. Of several other cytokines produced by Con A-stimulated spleen cells, IL-6 (20 ng/ml), IFN-gamma (45 ng/ml) and granulocyte-macrophage (GM)-CSF (10 ng/ml) greatly potentiated the fusion induced by 4 ng/ml of IL-4. The assay of these cytokines in Con A-CM proved that it contained 0.44 +/- 0.04 ng/ml of IL-4, 1.0 +/- 0.24 ng/ml of IL-6, 9.1 +/- 0.07 ng/ml of IFN-gamma, and 11.6 +/- 1.66 ng/ml of GM-CSF. When the potentiating effects of IL-6, IFN-gamma and GM-CSF on macrophage fusion were examined in the presence of 0.4 ng/ml of IL-4, only GM-CSF increased the fusion rate to the maximal level induced by Con A-CM at its physiologic concentration (10 ng/ml). The macrophage fusion induced by Con A-CM was greatly suppressed by adding antibody against GM-CSF. GM-CSF had a biphasic effect on growth and fusion, depending on its dose levels used: 0.01 to 0.1 ng/ml increased proliferation without inducing fusion and 10 ng/ml preferentially induced fusion. There was a negative relationship between macrophage growth and fusion. IL-4 was a potent inhibitor of proliferation of macrophages induced by GM-CSF. These results clearly indicate that GM-CSF is a major MFF present in Con A-CM.

Granulocyte-macrophage colony-stimulating factor is a major macrophage fusion factor present in conditioned medium of concanavalin A-stimulated spleen cell cultures

In 1983, we reported that the conditioned medium (CM) of spleen cell cultures treated with Con A greatly induced fusion of mouse alveolar macrophages within 2 to 3 days at a very high rate of more than 80% (Proc. Natl. Acad. Sci. USA 80:5583, 1983). In the course of examining macrophage fusion factors (MFF) present in Con A-CM, we found that IL-4 induced fusion of alveolar macrophages with a time course similar to that induced by Con A-CM. However, the maximal fusion rate induced by IL-4 (4 ng/ml) was about 35%. Furthermore, the fusion induced by Con A-CM was blocked only partially by adding IL-4 antibody, indicating that there are unknown MFF other than in Con A-CM. Of several other cytokines produced by Con A-stimulated spleen cells, IL-6 (20 ng/ml), IFN-gamma (45 ng/ml) and granulocyte-macrophage (GM)-CSF (10 ng/ml) greatly potentiated the fusion induced by 4 ng/ml of IL-4. The assay of these cytokines in Con A-CM proved that it contained 0.44 +/- 0.04 ng/ml of IL-4, 1.0 +/- 0.24 ng/ml of IL-6, 9.1 +/- 0.07 ng/ml of IFN-gamma, and 11.6 +/- 1.66 ng/ml of GM-CSF. When the potentiating effects of IL-6, IFN-gamma and GM-CSF on macrophage fusion were examined in the presence of 0.4 ng/ml of IL-4, only GM-CSF increased the fusion rate to the maximal level induced by Con A-CM at its physiologic concentration (10 ng/ml). The macrophage fusion induced by Con A-CM was greatly suppressed by adding antibody against GM-CSF. GM-CSF had a biphasic effect on growth and fusion, depending on its dose levels used: 0.01 to 0.1 ng/ml increased proliferation without inducing fusion and 10 ng/ml preferentially induced fusion. There was a negative relationship between macrophage growth and fusion. IL-4 was a potent inhibitor of proliferation of macrophages induced by GM-CSF. These results clearly indicate that GM-CSF is a major MFF present in Con A-CM.

The specific production of the third component of complement by osteoblastic cells treated with 1 alpha,25-dihydroxyvitamin D3

A 190 kDa protein was purified from conditioned media of mouse marrow-derived stromal cell (ST2) cultures treated with 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) and identified as the third component of mouse complement (C3). Northern and Western blot analysis revealed that the production of C3 by ST2 and primary osteoblastic cells was strictly dependent on 1 alpha,25(OH)2D3, but the production by hepatocytes was not. Adding 1 alpha,25(OH)2D3 together with mouse C3 antibody to bone marrow cultures greatly inhibited the formation of tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like multinucleated cells. Adding C3 alone induced no TRAP-positive cell formation. These results suggest that, in bone tissues, C3 is specifically produced by osteoblasts in response to 1 alpha,25(OH)2D3 and somehow involved in inducing differentiation of bone marrow cells into osteoclasts in concert with other factors produced by osteoblasts in response to 1 alpha,25(OH)2D3.

Interleukin 1 regulates the expression of osteopontin mRNA by osteoblasts

Osteopontin is a matrix protein which belongs to the integrin superfamily and is involved in cell adhesion. In the present study, we examined the regulation of the mRNA expression of osteopontin by interleukin 1 alpha (IL-1 alpha) in osteoblasts. IL-1 alpha greatly increased the steady-state level of osteopontin mRNA in both a mouse osteoblastic cell line (MC3T3-E1) and mouse primary osteoblast-like cells. The increase in the osteopontin mRNA expression by IL-1 alpha was dose-dependent at a range of 0.004-0.2 nM. This was most likely due to an increase in the transcriptional rate, not to an increase in the stability of osteopontin mRNA. The in vitro nuclear transcription experiment showed that IL-1 alpha-treated MC3T3-E1 cells increased the synthesis of osteopontin mRNA. Besides IL-1 alpha, tumor necrosis factor alpha (TNF-alpha), lipopolysaccharides (LPS) and 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) increased the osteopontin mRNA expression in both the clonal osteoblasts (MC3T3-E1) and the primary osteoblast-like cells. In response to such bone-resorbing agents, primary osteoblast-like cells expressed osteopontin mRNA much more strongly than primary fibroblast-like cells isolated from mouse calvaria. Both IL-1 alpha and 1 alpha,25(OH)2D3 greatly increased the production of 68 and 62 kDa phosphoproteins in conditioned media of MC3T3-E1 cell cultures, which probably correspond to osteopontin. These results suggest that osteopontin plays an important role in bone remodeling, in particular bone resorption.