Rapid killing of murine lymph node T blasts by intestinal intraepithelial lymphocytes in vitro

We examined the effect of murine intestinal intraepithelial lymphocytes (IEL) on the proliferation of murine lymph node T cells (LN-T) in vitro. An IEL fraction prevented the proliferation of LN-T stimulated with antigen and X-irradiated spleen cells, or with anti-CD3 monoclonal antibodies (mAb). Concanavalin A-activated LN-T were less sensitive. Such an inhibitory activity was recovered from a CD8-depleted population by panning of bulk IEL using anti-CD8 alpha mAb. This population of BALB/c IEL showed less granzyme A activity, and its surface markers were positive for CD8 (4%), CD3 (80-90%), CD4 (2-6%), alpha-beta TcR (45-70%), and gamma-delta TcR (4-9%). Asialo-GM1 and Thy1.2 were variably expressed, but interleukin-2 (IL-2) receptor-alpha and Fc gamma receptor were not. By contrast, no cytotoxicity against YAC-1 was detected in a CD8-depleted IEL population by a 6-h 51Cr-release assay. Although IEL from severe-combined immunodeficient mice lacking CD4, CD8 and TcR, but expressing IL-2 receptor, showed cytotoxicity against YAC-1, their inhibitory activity against LN-T was almost the same as that by IEL from BALB/c mice. When LN-T blasts (greater than 75% CD4+) activated with anti-CD3 were treated with CD8-depleted IEL, intact cellular DNA of the T blasts disappeared within 1 h with increased amounts of small-sized DNA. These results suggest that CD8- IEL directly and nonspecifically kill lymph node CD4+ T blasts and possibly down-regulate TcR-mediated proliferation of peripheral T cells in the gut epithelium.

Inhibitory effects of terfenadine on the rising phase of action potentials and sinus rates in isolated guinea-pig myocardium

1. Effects of terfenadine on the ventricular action potential and sinus rate of isolated guinea-pig myocardial preparations were examined to elucidate whether the drug has any cardioinhibitory effect. 2. Terfenadine significantly and concentration dependently decreased the maximum rate of rise (Vmax) of action potentials, the decrease of which was 60% of the control value at 2 x 10(-5) M. 3. Terfenadine decreased the sinus rate concentration dependently at 10(-6) M and higher concentrations; in some preparations, spontaneous beating was abolished at 2 x 10(-5) M (sinus arrest). 4. On the other hand, KW-4679 ((Z)-11-[3-(dimethylamino)propylidene]-6-11-dihydrodibenz[b, e]oxepin- 2-acetic acid hydrochloride), a new antiallergic drug having higher antiallergic potency than terfenadine, exerted a weaker inhibitory effect on the Vmax without affecting the sinus rate. 5. In conclusion, the antiallergic drug terfenadine has inhibitory effects on isolated myocardia. The cardioinhibitory effects of antiallergic drugs seem to be independent of their antiallergic potency.

Withdrawal of [corrected] estrogen increases hypothalamic neuropeptide Y (NPY) mRNA expression in ovariectomized obese rat

We determined the changes in neuropeptide Y (NPY) mRNA expression of the arcuate nucleus (ARC) in sham-operated (SHAM) and bilaterally ovariectomized (OVX) rats with estradiol (E2) supplement. Ovariectomy increases body weight gain for 3 weeks, accompanied by an increase of daily food intake. Ovariectomy significantly reduced serum corticosterone levels. E2 supplement reversed the effects of ovariectomy on body weight gain, food intake and serum corticosterone levels. Ovariectomy significantly increased NPY mRNA expression in the ARC. E2 supplement decreased NPY mRNA expression in the ARC of OVX rats. The present findings indicated that hypothalamic NPY mRNA expression, which involves the regulation of feeding behavior, are in parallel with circulating estrogen levels. Hypothalamic NPY mRNA expression may be important in the induction of hyperphagia after the withdrawal of estrogen by bilateral ovariectomy.

Oral biological activities of spontaneous nitric oxide releasers are accounted for by their nitric oxide-releasing rates and oral absorption manners

We examined whether p.o. biological activities of (+/-)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide (FK409), a spontaneous nitric oxide (NO) releaser, and the derivatives, i.e., (+/-)-[(E)-4-ethyl-3-[(Z)-hydroxyimino]-5-nitro-3-hexenyl]-3 - pyridinecarboxamide (FR144420) and (+/-)-N-[(E)-4-ethyl-3-[(Z)-hydroxyimino]-6-methyl-5- nitro-3-heptenyl]-3-pyridinecarboxamide (FR146801), could be accounted for by their NO-releasing rates and p.o. absorption manners. These compounds spontaneously released NO with the rates in the rank order of FK409 > FR144420 > FR146801. Total contribution of these drugs as NO donors in vivo was almost the same from the determination of urinary nitrite/nitrate (NOx) levels after p.o. administration of the compounds at 10 mg/kg to rats. Plasma NOx level after p.o. administration of FK409 at 10 mg/kg to rats reached maximal level at 120 min, and decreased gradually. On the other hand, plasma NOx levels time-dependently increased during 360 min after p.o. administration of FR144420 and FR146801 at the same dose. FK409 and FR144420 showed hypotensive effects immediately after p.o. administration at 10 mg/kg to rats, and the maximum response of FR144420 was less and the duration of the effect was longer than those of FK409, respectively. On the other hand, FR146801, which is most stable in solution, did not show any significant hypotensive effect during 240 min after p.o. administration at the same dose. In conclusion, the response and the duration of biological activity after p.o. administration of three spontaneous NO releasers can be closely accounted for by their NO-releasing rates and p.o. absorption manners.

Quantitation of L-amino acids by substrate recycling between an aminotransferase and a dehydrogenase: application to the determination of L-phenylalanine in human blood

A spectrophotometric recycling assay for the quantitation of L-phenylalanine (and phenylpyruvate) has previously been reported (Cooper et al., Anal. Biochem. 183, 210-214, 1989). The procedure involves the coupling of bacterial phenylalanine dehydrogenase with rat kidney cytosolic glutamine transaminase K. The latter enzyme possesses high affinity for phenylpyruvate. Recycling results in a > or = 50-fold increase in sensitivity over that of a conventional spectrophotometric "end point" analysis procedure. The spectrophotometric recycling procedure has now been adapted to the measurement of L-phenylalanine in microliter quantities of human blood. This procedure is 10 times more sensitive than provided by a commercial kit for the spectrophotometric measurement of L-phenylalanine in human blood. Moreover, the present results suggest that the recycling procedure adapted for fluorometry will be even more sensitive. By use of suitable dehydrogenases and amino acid aminotransferases it should be possible to quantitate amino acids (in addition to phenylalanine) in small quantities of human blood.

Deletion mapping on chromosome 1p in well-differentiated gastric cancer

To define the region on the short arm of chromosome 1 that is thought to include one or more tumour-suppressor genes for gastric cancers, we carried out loss of heterozygosity (LOH) studies in 26 gastric adenocarcinomas, using three restriction fragment length polymorphism (RFLP) markers and nine microsatellite markers. All tumours were informative with at least one locus; three revealed replication errors (RERs) at multiple microsatellite loci, and interstitial or telomeric allelic deletions were observed in 12 cases. Deletion mapping of these tumours defined a commonly deleted region between two loci, D1S201 and D1S197, that are 13 cM apart. As two loci within the commonly deleted region, D1S57 (pYNZ2) and D1S62 (pTHI54), were mapped respectively to 1p35 and 1p34.3 by fluorescence in situ hybridisation, we conclude that a locus likely to contain a tumour-suppressor gene for gastric cancer is located within a 13 cM region encompassing two chromosomal bands.

Effect of terfenadine and KW-4679, a novel antiallergic compound, on action potential of guinea pig ventricular myocytes

It has been reported that terfenadine caused torsade de pointes ventricular arrhythmias. The prolongation of action potential duration (APD) in ventricles is considered to be one of the mechanisms of this adverse effect. We examined the effect of antiallergic drugs, terfenadine and KW-4679 ((Z)-11-[3-(dimethylamino)propylidene]-6,11-dihydrodibenz[b, e]oxepin- 2-acetic acid hydrochloride), on action potentials in isolated guinea pig ventricular myocytes. Terfenadine (30 nM-1 microM) increased APD in a concentration-dependent manner. On the other hand, KW-4679 (0.1 microM-100 microM) exerted no significant effects on action potential parameters. These results present no evidence that KW-4679 has the possibility to cause ventricular arrhythmias.

Increased serum human granulocyte colony-stimulating factor (G-CSF) levels following intravenous infusion of high-dose methylprednisolone

Serum granulocyte colony-stimulating factor (G-CSF) level were measured for 24 h in 6 patients with hematological disorders and two patients with Graves' disease associated with malignant exophthalmos after iv infusion of high-dose methylprednisolone (HDMP) (20 mg/kg BW) for 2 h starting at 0900 h. Saline solution (500 ml) was infused iv for 2 h as a control on two days before starting the HDMP therapy. Serum G-CSF levels increased with the mean peak values at 4 h after the HDMP therapy (mean +/- SD: 488.1 +/- 125.8 pg/ml vs. saline control 74.4 +/- 21.9 pg/ml, P < 0.01). Circulating absolute neutrophil counts (ANC) also increased with the mean peak values at 24 h after the HDMP (6,057 +/- 1,460 / microliters vs. saline control 2,007 +/- 390 / microliters, P < 0.025). These findings indicate that glucocorticoid has a stimulating effect on G-CSF release and that the increased G-CSF release could be involved, at least partly, in neutrophilia induced by glucocorticoid.

[Long-term effect after total parathyroidectomy with autotransplantation for secondary hyperparathyroidism]

Although the short-term outcome of total parathyroidectomy combined with autotransplantation in cases of renal osteodystrophy has been reported by many investigators, few studies have been made on the long-term outcome of this surgical technique. We recently examined the long-term outcome of this surgery by following 19 cases for more than one year (range: 12-70 months, mean: 31.7 months). During the follow-up period, changes in subjective symptoms, biochemical parameters and bone mineral density (BMD) were monitored. At the end of the follow-up period, C-parathyroid hormone (C-PTH) and alkaliphosphatase (ALP) were significantly lower than their preoperative levels. Ca, P and %BMD showed no significant change from their preoperative levels, although %BMD tended to be higher than its preoperative level. Depending on the presence or absence of osteoarticular pain at the end of the follow-up period, the patients were divided into the improved group and the non-improved group. Of the 5 patients allocated to the non-improved group, 4 were female and only 1 was male. C-PTH and ALP were significantly higher in the non-improved group. %BMD was higher in the improved group than in the non-improved group, although this difference was not significant. In the non-improved group, 2 patients were suspected of having extra parathyroids, 1 was suspected of having recurrence, and 2 were suspected of having postoperative osteomalacia. Postoperative reduction in BMD was only seen in females, suggesting its relationship to postmenopausal osteoporosis.

Augmented immunological activities of recombinant lipopolysaccharide possessing the mannose homopolymer as the O-specific polysaccharide

Recombinant lipopolysaccharide possessing the mannose homopolymer as the O-specific polysaccharide was manufactured genetically by transforming Escherichia coli K-12 with various rfb genes capable of synthesizing the mannose homopolymer. Recombinant lipopolysaccharide exhibited levels of anticomplement activity, adjuvant activity, and regional lymph node-enlarging activity much higher than those exhibited by the original rough-type lipopolysaccharide from E. coli K-12 or lipopolysaccharide possessing the heteropolysaccharide from E. coli O111. Immunological activities of recombinant lipopolysaccharide were as strong as those of wild-type lipopolysaccharide possessing the mannose homopolymer. Characteristic activities of wild-type lipolysaccharide possessing the mannose homopolymer were exhibited by recombinant lipopolysaccharide. The abilities of lipopolysaccharide to activate B cells polyclonally and to produce cytokines did not seem to be related to the presence of the mannose homopolymer. Therefore, it was suggested that the mannose homopolymer in the O-specific polysaccharide might exclusively enhance anticomplement activity, adjuvant activity, and regional lymph node-enlarging activity among various lipid A activities.

Positive inotropic and chronotropic effects of beraprost sodium, a stable analogue of prostacyclin, in isolated guinea pig myocardium

1. Inotropic and chronotropic effects of beraprost sodium (beraprost), a chemically stable prostacyclin analogue, were examined in isolated myocardial preparations of guinea pigs. 2. In the left atria, 10(-9) - 10(-7) M beraprost had no significant effect on the contractile force, but 10(-6) and 10(-5) M produced a concentration-dependent positive inotropic response. This effect was antagonized by S-145, a potent and selective thromboxane A2 (TXA2) receptor antagonist, but not by propranolol. 3. Beraprost, from 10(-9) to 10(-5) M, had no significant inotropic effect in the right ventricular papillary muscles. 4. In the right atria, 10(-9) and 10(-8) M beraprost had no significant effect, but 10(-7) - 10(-5) M caused an increase in beating rate; this effect was not affected by S-145. 5. The present study demonstrates that beraprost has positive inotropic and chronotropic effects at high doses on isolated guinea pig atria. The inotropic effect may be mediated by the TXA2 receptor, but some mechanism other than the TXA2 receptor is responsible for the chronotropic effect.

Association of tumor cell proliferation with lymph node metastasis in early gastric cancer

Recently, many studies have reported on the relationship between malignant potential of neoplasms and cell proliferation. Proliferating cell nuclear antigen (PCNA) is an auxiliary protein of DNA polymerase delta and is considered to correlate with the cell's proliferative state. In this study, we investigated the correlation between tumor cell proliferation and nodal status of early gastric carcinoma. One hundred two endoscopically biopsied specimens from patients with early gastric carcinoma prior to operation were investigated by an immunohistochemical study, using anti-PCNA monoclonal antibody. Correlation of PCNA labeling index (percentage of positive cells per over 500 tumor cells) with nodal status were studied. PCNA labeling index in patients with lymph node metastasis was significantly higher in those without metastasis. Moreover, multivariate analysis indicated that PCNA labeling index is an independent significant factor for lymph node metastasis. As a result of this study, PCNA labeling index was suggested to be effective as one of the predictors of lymph node metastasis.

Inactivation of brain and kidney aspartate aminotransferases by S-(1,2,-dichlorovinyl)-L-cysteine and by S-(1,1,2,2,-tetrafluoroethyl)-L-cysteine

Long-term exposure to trichloroethylene can cause kidney cancer in experimental animals and humans. In addition, dichloroacetylene (a breakdown product of trichloroethylene) is nephrotoxic and neurotoxic. Both trichloroethylene and dichloroacetylene are metabolized in part to the corresponding cysteine S-conjugate (i.e. S-(1,2-dichlorovinyl)-L-cysteine) which is toxic. Cysteine S-conjugate beta-lyases convert S-(1,2,dichlorovinyl)-L-cysteine to pyruvate, ammonia and a reactive fragment that adds to macromolecules, depletes cellular thiols and causes lipid peroxidation. We now show that S-(1,2-dichlorovinyl)-L-cysteine and another nephrotoxic cysteine S-conjugate, S-(1,1,2,2-tetrafluoroethyl)-L-cysteine, inactive purified cytosolic aspartate aminotransferase and purified alanine aminotransferase. These cysteine S-conjugates also inactive aspartate aminotransferase in cytosolic and mitochondrial fractions of rat brain and kidney. The present results suggest that some halogenated xenobiotics may be toxic in part through their conversion to the corresponding cysteine S-conjugate which inactivates key pyridoxal 5'-phosphate-containing enzyme.

The major component of Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of murine intraepithelial lymphocytes is granzyme A

Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of intraepithelial lymphocytes in the murine intestine (iIEL) were characterized. BLT-specific proteases were isolated with the Sephacryl S-200 column chromatography, and the sample isolated contained a protein with a molecular weight of 58 kDa. The 58 kDa protein consisted of the homodimer of the 30 kDa subunits. The 58 kDa protease was detected by [3H] diisopropylfluorophosphate (DFP)-labeling, and also detectable by the immunoblotting using an antibody against the partial synthetic peptide of granzyme A. The cytoplasmic granules of iIEL were stained positively by an immunofluorescence with anti-granzyme A antibody. Therefore, it was suggested that the major BLT-specific proteases present in cytoplasmic granules of iIEL might be granzyme A.

[Spontaneous renal rupture due to xanthogranulomatous pyelonephritis; a case report]

A 47-year-old female was admitted with colicky pain in the left flank. Ultrasonography and abdominal CT revealed left perirenal hematoma. Abdominal CT revealed a multilocular cystic lesion in the upper pole of the left kidney. Renal angiography revealed left renal cell carcinoma. Left nephrectomy was performed under a tentative diagnosis of left renal cell carcinoma. However, pathological diagnosis was xanthogranulomatous pyelonephritis. Xanthogranulomatous pyelonephritis is an atypical form of chronic renal parenchymal infection that can be classified as diffuse type or focal type. Preoperative diagnosis of focal xanthogranulomatous pyelonephritis is difficult because of clinical and radiological similarities to renal cell carcinoma. Our case is presented with a brief review of the literature.

Specific acceptance of fetal bowel allograft in mice after combined treatment with anti-intercellular adhesion molecule-1 and leukocyte function-associated antigen-1 antibodies

OBJECTIVE

The aim of this study was to see whether tolerance could be induced by simultaneous administration of monoclonal antibodies (MoAbs) to intercellular adhesion molecule-1 (ICAM-1) and leukocyte function-associated antigen-1 (LFA-1) after transplantation of fetal small bowel between fully incompatible mice strains.

METHODS

Fetal small bowel from either BALB/c (H-2d) or C3H/He (H-2k) mice was transplanted into the space between the peritoneum and rectus abdominis of adult C3H/He recipient mice. Syngeneic (n = 6) and two allogeneic transplant groups were made. In one of the allogeneic groups (n = 8), no immunosuppressant was given. In the other allogeneic group (n = 13), both anti-LFA-1 and anti-ICAM-1 MoAbs (50 micrograms each/mouse/day) were given intraperitoneally after transplantation for the first 4 weeks. In the syngeneic and untreated allogeneic groups, all mice were killed 4 weeks after transplantation. In the treated allogeneic group, eight mice were killed 6 weeks after cessation of the MoAb treatment. At the time the mice were killed, the bowel graft as well as the recipient spleen were taken for histologic analysis and cytotoxic T-lymphocyte (CTL) assay, respectively. Each mouse in the remaining treated five mice was transplanted with BALB/c and C57BL/6 (as third-party) full-thickness skin simultaneously 8 weeks after cessation of the MoAb treatment.

RESULTS

All grafts in the syngeneic group survived with normally developing villi, whereas all grafts in the untreated allogeneic group disappeared. In the treated allogeneic group, all allografts developed normal mucosa without any sign of rejection. Splenocytes from the recipient mice in the untreated allogeneic group showed increased CTL induction against donor-type alloantigen (p < 0.005), compared with that in the syngeneic group. Suppressed CTL induction against donor-type alloantigen was observed in the treated allografted recipient (p < 0.001), whereas CTL induction against third-party alloantigen was intact (p = NS). Third-party skin graft was normally rejected within 10 days, whereas donor-type skin graft was accepted in all mice tested.

CONCLUSIONS

Specific tolerance for fetal bowel allografts could be induced by a relatively short-term treatment with anti-ICAM-1 and anti-LFA-1 MoAbs. This mode of immunointervention could perhaps be applied to humans undergoing small-bowel transplantation.

Lack of intestinal pacemaker (C-KIT-positive) cells in infantile hypertrophic pyloric stenosis

The pathogenesis of infantile hypertrophic pyloric stenosis (IHPS) is not well understood. Recent studies have shown that the protonocogene c-kit is essential for the development or maintenance of autonomic gut motility, and also show that the c-kit gene protein product (C-KIT) positive cells in the mammalian gut are responsible for intestinal pacemaker activity. This study examines cells in the pyloric muscles of 23 patients (16 with IHPS, 7 controls) for the presence of the C-KIT (C-KIT+), using immunohistochemical techniques with antihuman C-KIT sera. In the controls, many C-KIT immunoreactive (IR+) cells were observed in the muscle layers. The myenteric plexuses were demarcated by a moderate number of C-KIT-IR+ cells. However, in the IHPS patients, C-KIT-IR were either absent or significantly reduced. No C-KIT-IR+ cells were found around the myenteric plexuses. These findings suggest that a lack of c-kit expression (as an indicator of intestinal pacemaker activity) in the hypertrophic pyloric smooth muscles may be an important factor in the pathogenesis of IHPS.

A possible mechanism of increase in serum alkaline phosphatase activity in rats given granulocyte colony-stimulating factor

Recombinant human granulocyte colony-stimulating factor (G-CSF) at a dose of 1 to 300 micrograms/kg/day was administered intravenously to rats daily for 13 weeks. Serum alkaline phosphatase (ALP) activity increased dose-dependently with leukocytosis. Most of the increased leukocytes were segmented neutrophils, and neutrophil alkaline phosphatase (NAP) scores were elevated markedly. Serum ALP activity correlated very well with the segmented neutrophil counts, and the coefficient of correlation was more than 0.97 in both sexes. Pathological examinations revealed splenomegaly and a marked increase in neutrophils in the red pulp of the spleen. In the spleen, phagocytosis of neutrophils by macrophages was observed. These data indicate that the increased ALP was of neutrophil origin. Serum ALP activity may be increased by the direct release of ALP from the high number of neutrophils into the blood, or by the leakage of ALP into the blood mainly from the spleen where many neutrophils are pooled and destroyed by the macrophage system.

Recent characterization of Salmonella strains isolated from chickens in Zambia

Among the 23 Salmonella strains isolated from 21 diseased chicken and 2 embryonated eggs in 6 poultry farms near Lusaka City in Zambia, serovars identified were S. Gallinarum (11 strains), S. Agona (7 strains), S. Alamo (1 strain), S. Infantis (1 strain), S. Virginia (1 strain), S. Haifa (1 strain), and S. Dublin (1 strain). S Gallinarum was detected at the highest incidence and from all the poultry farms. Fourteen serovars have been reported for the chickens in Zambia so far. Three serovars (S. Alamo, S. Haifa, S. Virginia) were newly identified in this study.

Mechanistical studies of the inhibition of intercellular communication by organochlorine compounds

Many hydrocarbons are environmental pollutants that, due to their lipophilicity and chemical stability, accumulate in biological systems including milk and body fat. A number of investigations have demonstrated that many organochlorine compounds can act as tumour promoters in vivo and inhibit gap junctional intercellular communication between cells in culture. In the present study we have investigated the dioxin 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), different polychlorinated biphenyls, chlorinated paraffins and the pesticide endosulfan. Using techniques of scrape loading dye/transfer and Western blot analysis the function, expression and phosphorylation of different connexins in vitro and in vivo were studied. The results show a good correlation between the ability to act as a tumour promoter and to interfere with gap junctional intercellular communication. All tested compounds inhibited the intercellular communication in a liver derived cell line (IAR 20). However, the results show that the time to inhibition varies between the different agents. Endosulfan and chlorinated paraffins inhibit the communication within one hour, whereas dioxin like substances need to expose the cells for 48 hours before the communication is affected.

Screening of plant growth regulators acting on Arabidopsis thaliana

Our screening system using Arabidopsis thaliana, enabled us to evaluate the effect of 38 known growth regulators on plant growth promotion. Eleven compounds in the study were found to show a promoting effect upon Arabidopsis dry weight and leaf number; in particular, oligosaccharides (OS) such as raffinose and stachyose had a marked effect. Detailed experiments indicated that the effect of OS on plant growth was not merely derived from its potential carbon source. Among the monosaccharides comprising stachyose, galactose showed the best promoting effect on plant growth.

Effects of cyclic adenosine 3',5'-monophosphate on chondrocyte terminal differentiation and cartilage-matrix calcification

We examined the effects of cyclic AMP on terminal differentiation and calcification in rabbit growth plate chondrocyte cultures. Dibutyryl cAMP (dbcAMP), as well as 8-bromo-cAMP abolished the increases in chondrocyte size, alkaline phosphatase activity, type X collagen synthesis, 1 alpha, 25-dihydroxyvitamin D3 receptor synthesis, the incorporation of 45Ca into insoluble material, and the calcium content. All of these occurred in parallel untreated cultures during the hypertrophic (terminal) stage. The inhibition of alkaline phosphatase by dbcAMP was detectable after 24 h, and this effect was reversible. dbcAMP and 8-bromo-cyclic AMP inhibited alkaline phosphatase induction and calcification at low concentrations (3-5 microM), whereas 10-30-fold higher concentrations were required to stimulate proteoglycan synthesis. These findings suggest that cAMP plays a crucial role in suppressing terminal differentiation of chondrocyte and cartilage-matrix calcification.