Planar catechin increases bone mass by regulating differentiation of osteoclasts in mice

OBJECTIVES

While catechins have been reported to exhibit potential to benefit osteoporosis patients, the effects of planar catechin (PCat), synthesized during the development of drugs for Alzheimer's disease, have not been clearly elucidated. Here, we examined the effects of PCat on mouse bone metabolism both in vivo and in vitro.

METHODS

Six week old female mice were orally administered PCat (30 mg/kg) every other day for four weeks, and their femurs were analyzed using micro-computed tomography imaging. Osteoclasts and osteoblasts were collected from mice and cultured with PCat. Subsequently, osteoclast formation and differentiation and osteoblast differentiation were observed.

RESULTS

Mice orally administered PCat displayed significantly increased femur bone mass compared to the control group. Quantitative polymerase chain reaction findings indicated that PCat addition to osteoclast progenitor cultures suppressed osteoclast formation and decreased osteoclast marker expression without affecting the proliferative potential of the osteoclast progenitor cells. Addition of PCat to osteoblast cultures increased osteoblast marker expression.

CONCLUSIONS

PCat inhibits osteoclast differentiation and promotes osteoblast differentiation, resulting in increased bone mass in mice. These results suggest that PCat administration is a promising treatment option for conditions associated with bone loss, including osteoporosis.

Tacrolimus, FK506, promotes bone formation in bone defect mouse model

OBJECTIVES

Some studies have reported that tacrolimus (FK506), an immunosuppressant, may have positive effects on bone formation. However, the precise effects of FK506 on bone repair or osteoblasts remain inadequately elucidated, and limited research has explored the outcomes of its use in an in vivo mouse model. This study aims to examine the effects of FK506 on bone repair and osteoblast functions using bone defect and BMP-2-induced ectopic ossification mouse models, as well as cultured primary mouse osteoblasts treated with FK506.

METHODS

We established mouse models of femur bone defect and BMP-2-induced ectopic ossification to evaluate the effect of FK506 on new bone formation, respectively. Additionally, primary mouse osteoblasts were cultured with FK506 and examined for gene expressions related to osteoblast differentiation.

RESULTS

While FK506 promoted the repair of bone defect areas in the femur of the bone defect mouse model, it also led to widespread abnormal bone formation outside the intended area. Additionally, following the implantation of a collagen sponge containing BMP-2 into mouse muscle tissue, FK506 was found to promote ectopic ossification and enhance BMP-2-induced osteoblast differentiation in vitro. Our findings also revealed that FK506 increased the number of immature osteoblasts in the absence of BMP-2 without affecting osteoblast differentiation. Furthermore, direct effects were observed, reducing the ability of osteoblasts to support osteoclastogenesis.

CONCLUSIONS

These results indicate that FK506 increases new bone formation during bone repair and influences the proliferation of immature osteoblasts, as well as osteoblast-supported osteoclastogenesis.

Metagenomic Analysis of Bacterial Microflora in Dental and Atherosclerotic Plaques of Patients With Internal Carotid Artery Stenosis

Background

Internal carotid artery stenosis is primarily attributed to atherosclerosis in the carotid artery bifurcation. Previous studies have detected oral bacteria in atherosclerotic lesions, suggesting an association between oral bacteria and atherosclerosis. In this study, we compared the bacterial flora of the atherosclerotic plaque in the carotid artery and dental plaque of patients with internal carotid artery stenosis using 16S ribosomal RNA (16S rRNA) metagenomic sequencing.

Methods

Fifty-four patients who underwent internal carotid endarterectomy for internal carotid artery stenosis at the Showa University Hospital between April 2016 and February 2018 were included. Polymerase chain reaction targeting the 16S rRNA gene detected bacterial DNA in the carotid plaques of 11 cases, of which only 5 could be further analyzed. Thereafter, DNA extracted from the carotid and oral plaques of these 5 cases were analyzed using metagenomic sequencing targeting 16S rRNA. In addition, their general condition and oral conditions were evaluated. The patients were classified into symptomatic and asymptomatic groups based on the presence or absence of symptoms of transient ischemic attack, and their bacterial flora was evaluated.

Results

The results demonstrated that the microflora of carotid plaques (n = 5) contained bacterial species from 55 families and 78 genera. In addition, 86.5% of the bacteria detected in the carotid plaques were also detected in oral plaques. Cariogenic and periodontopathic bacteria accounted for 27.7% and 4.7% of the bacteria in the carotid plaques, respectively.

Conclusions

These results suggest that oral bacteria are directly or indirectly involved in the pathogenesis of atherosclerosis. More extensive studies of oral commensal bacteria detected in extra-oral lesions are warranted to comprehensively investigate the role of oral bacteria in the pathogenesis of systemic diseases.

Oral commensal bacterial flora is responsible for peripheral differentiation of neutrophils in the oral mucosa in the steady state

OBJECTIVES

Commensal bacteria in the host body play a fundamental role in the differentiation and maintenance of the immune system. Studies on intestinal immunity have revealed that, under steady-state conditions, microflora have an important role in the maintenance of health. However, the role of oral commensal bacteria on the oral immune system is still unclear. Here, we clarify the interactions between commensal bacteria and the oral mucosal immune system under steady-state conditions.

METHODS

We used germ-free mice that had never been exposed to bacteria and conventional mice grown with normal bacterial flora. Oral cells were isolated from the oral mucosa, stained with specific antibodies, and analyzed by flow cytometry. For the detection of myeloperoxidase and intracellular cytokines, oral cells were stimulated with N-formyl-methionine-leucyl-phenylalanine and phorbol 12-myristate 13-acetate/ionomycin, respectively.

RESULTS

We found that the oral mucosa harbored more neutrophils in germ-free mice than in conventional mice. However, the majority of neutrophils in the germ-free oral mucosa exhibited an immature phenotype. Other immune cells, including macrophages, T cells, and B cells, in the oral mucosa of germ-free mice showed similar differentiation to those in conventional mice. These results indicate that in the steady-state oral mucosa, the normal commensal flora promote the peripheral differentiation of neutrophils.

CONCLUSIONS

The presence of commensal flora is critical for the development of adequate immune system in the oral mucosa.

Particle Size Analysis in Aerosol-Generating Dental Procedures Using Laser Diffraction Technique

The global outbreak of coronavirus disease 2019 (COVID-19) has raised concerns about the risk of airborne infection during dental treatment. Aerosol-generating dental procedures (AGDP) produce droplets and aerosols, but the details of the risks of COVID-19 transmission in AGDP are not well-understood. By discriminating between droplets and aerosols, we devised a method to measure particle size using laser diffraction analysis and evaluated aerosols generated from dental devices for providing a basis for proper infection control procedures. The droplets and aerosols generated from dental devices were characterized by multimodal properties and a wide range of droplet sizes, with the majority of droplets larger than 50 μm. AGDP emitted few aerosols smaller than 5 μm, which are of concern for pulmonary infections due to airborne transmission. In addition, the use of extraoral suction was found to prevent the spread of aerosols from high-speed dental engines. This study suggests that the risk of aerosol infections is considerably limited in regular dental practice and that current standard precautions, such as mainly focusing on protection against droplet and contact infections, are sufficient. While several cases of airborne transmission of COVID-19 in general clinics and emergency hospitals have been reported, cluster outbreaks in dental clinics have not yet been reported, which may indicate that AGDP does not pose a significant threat in contributing to the spread of SARS-CoV-2.

Association between Oral Frailty and Dietary Variety among Community-Dwelling Older Persons: A Cross-Sectional Study

OBJECTIVE

To examine the association between the severity of oral frailty (OF), which is one of the comprehensive oral functions evaluated, and dietary variety in community-dwelling older persons.

DESIGN

Cross-sectional study.

SETTING

Community-based.

PARTICIPANTS

A total of 769 community-dwelling older persons aged 65 and over.

INTERVENTIONS

We examined basic demographic information, functional status, cognitive status, depressive symptoms, medical history, and oral functions of the participants.

MEASUREMENTS

OF was defined by 1-2 and 3 or more of 6 items of oral function evaluation in the pre-oral frailty and oral frailty groups, respectively. Dietary variety was assessed using the dietary variety score (DVS). The participants were categorized into 3 groups for evaluation: those with a low score (0-2), medium score (3-5), and high score (≥6). Ordinal logistic regression analysis was performed to examine the association between OF and DVS.

RESULTS

The rate of OF in the participants was 21.6%, and its severity was significantly associated with DVS after adjusting for potential confounders (Pre-OF; adjusted odds ratio [OR] = 1.687, 95% confidence interval [CI] = 1.219-2.335, OF; adjusted OR = 2.857, 95% CI = 1.489-5.484).

CONCLUSION

The severity of OF was significantly associated with DVS in community-dwelling older persons. This suggests that DVS may be useful in understanding the effects of OF on the nutritional status. Further longitudinal studies are needed to elucidate the association between OF and DVS.

Effects of lipid metabolism on mouse incisor dentinogenesis

Tooth formation can be affected by various factors, such as oral disease, drug administration, and systemic illness, as well as internal conditions including dentin formation. Dyslipidemia is an important lifestyle disease, though the relationship of aberrant lipid metabolism with tooth formation has not been clarified. This study was performed to examine the effects of dyslipidemia on tooth formation and tooth development. Dyslipidemia was induced in mice by giving a high-fat diet (HFD) for 12 weeks. Additionally, LDL receptor-deficient (Ldlr^−/−) strain mice were used to analyze the effects of dyslipidemia and lipid metabolism in greater detail. In the HFD-fed mice, incisor elongation was decreased and pulp was significantly narrowed, while histological findings revealed disappearance of predentin. In Ldlr^−/− mice fed regular chow, incisor elongation showed a decreasing trend and pulp a narrowing trend, while predentin changes were unclear. Serum lipid levels were increased in the HFD-fed wild-type (WT) mice, while Ldlr^−/− mice given the HFD showed the greatest increase. These results show important effects of lipid metabolism, especially via the LDL receptor, on tooth homeostasis maintenance. In addition, they suggest a different mechanism for WT and Ldlr^−/− mice, though the LDL receptor pathway may not be the only factor involved.

A Targeted Genetic Association Study of the Rare Type of Osteomyelitis

Chronic nonbacterial osteomyelitis is a rare bone disorder that can be found in the jaw. It is often associated with systemic conditions, including autoimmune deficiencies. However, little is known about how the genetic and immunologic background of patients influences the disease. Here, we focus on human leukocyte antigen (HLA), killer cell immunoglobulin-like receptors (KIRs), and their specific combinations that have been difficult to analyze owing to their high diversity. We employed a recently developed technology of simultaneous typing of HLA alleles and KIR haplotype and investigated alleles of the 35 HLA loci and KIR haplotypes composed of centromeric and telomeric motifs in 18 cases and 18 controls for discovery and 472 independent controls for validation. We identified an amino acid substitution of threonine at position 94 of HLA-C in combination with the telomeric KIR genotype of haplotype tA01/tB01 that had significantly higher frequency (>20%) in the case population than in both control populations. Multiple logistic regression analysis based on a dominant model with adjustments for age and sex revealed and validated its statistical significance and high predictive accuracy (C-statistic ≥0.85). Structure-based analysis revealed that the combination of the amino acid change in HLA-C and the telomeric genotype tA01/tB01 could be associated with lower stability of HLA-C. This is the first case-control study of a rare disease that employed the latest sequencing technology enabling simultaneous typing and investigated amino acid polymorphisms at HLA loci in combination with KIR haplotype.

Peripheral facial palsy after bilateral sagittal split ramus osteotomy: case report

Bilateral sagittal split ramus osteotomy (BSSRO) is commonly used in orthognathic surgery. Although abnormal sensation in areas that are innervated by the inferior alveolar nerve is a well-known neurological complication of mandibular osteotomy, facial palsy is rare postoperatively. We present a case of peripheral facial palsy that developed the day after BSSRO to correct a mandibular protrusion in a 42-year-old man. Oral prednisolone was begun on the second day postoperatively, and was gradually tapered off over time. One month after operation, he had gradually recovered all movements in his right facial muscle and, after two months, had completely recovered without residual asymmetry. Possible causes of the palsy were compression of the facial nerve as a result of the insertion of a retractor around the posterior border of the ramus, and postoperative oedema. Peripheral facial palsy after BSSRO should be considered a rare, but possible, complication and as such, should be mentioned in consent forms.

Whole Blood Platelet Aggregation Test and Prediction of Hemostatic Difficulty After Tooth Extraction in Patients Receiving Antiplatelet Therapy

When patients on antiplatelet therapy (APT) require minor invasive surgery, APT is usually continued to limit the risk of thrombosis. However, the possibility of hemostatic difficulties necessitates the monitoring of platelet aggregation to prevent unexpected bleeding. We examined whether whole blood aggregometry as a point-of-care testing (POCT) could be useful as a tool for predicting hemostatic difficulties. Sixty-five patients receiving APT and 15 patients who were not receiving APT were enrolled in the present study; all patients were scheduled to undergo a tooth extraction. Whole blood samples were obtained and were examined using multiple electrode aggregometry. The aggregometry was performed using arachidonic acid (AA), adenosine diphosphate (ADP), and thrombin receptor activating peptide. Hemostatic difficulty was defined as a need for more than 10 minutes of compression to achieve hemostasis. The AA test results were significantly lower in patients treated with aspirin (control: 97.7 [29.0] U, aspirin: 14.5 [7.2] U, P < .001). The ADP test results were also significantly lower in patients treated with a P2Y₁₂ inhibitor (control: 77.7 [21.7] U, P2Y₁₂ inhibitor: 37.3 [20.4] U, P < .01). Six of the examined cases exhibited hemostatic difficulties. The cutoff values for the prediction of hemostatic difficulty were 16.5 U for the AA test (sensitivity, 0.833; specificity, 0.508) and 21 U for the ADP test (sensitivity, 0.847; specificity, 0.500). Our study showed that whole blood aggregometry was useful as a POCT for the prediction of hemostatic difficulties after tooth extraction in patients receiving APT.

Autocrine motility factor and its receptor expressions in human oral squamous cell carcinoma (SCC) cells

Autocrine motility factor (AMF) a tumor-secreted 55 kDa cytokine induces tumor cell motility by a signal transduction pathway mediated by interaction with its receptor (AMFR) a cell surface glycoprotein of 78 kDa (gp78). Here, AMF secreted by the metastatic LMF4 human oral squamous-cell carcinoma (SCC) cells, induced dose- and time-dependent morphological changes and chemotaxis of the producing cells. Expression of AMFR mRNA was associated with the metastatic ability of SCC cell variants. The data presented show for the first time that SCC cells produce AMF and express AMFR and the expression is related to their invasiveness and metastatic potentials.

Thymidylate synthase, thymidine phosphorylase and orotate phosphoribosyl transferase levels as predictive factors of chemotherapy in oral squamous cell carcinoma

We conducted a clinicopathologic study on protein and mRNA levels of thymidylate synthase (TS), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT) using biopsy tissue specimens before treatment. The mRNA levels have been measured in tumor cells microdissected from paraffin-embedded specimens (Danenberg Tumor Profile method: DTP method). We studied the mRNA and protein expression as effect predictive factors in chemotherapy. The subjects consisted of 20 cases of untreated oral squamous cell carcinoma who had undergone chemotherapy with TS-1 (16 males and 4 females, tongue in 8 cases, upper gingiva in 3 cases, lower gingiva in 3 cases, buccal mucosa in 5 cases and floor of the mouth in 1 case). TS gene expressions of the responders were lower than those for the nonresponders. Furthermore, regarding males who were less than 70 years of age, stage I and II, well differentiated type and tongue, TS mRNA expression of the responders were lower than that for the nonresponders. The mRNA expression of OPRT for the male responders was lower than that for the nonresponders. No remarkable difference was observed by immunohistochemistry. In this study, the measurement of the TS levels using the DTP method may potentially act as a predictive factor of antitumor effectiveness.

[Nedaplatin (NDP)-combination therapy (NDP/5-FU,NDP/S-1) for oral cancer]

PURPOSE

The present study evaluated the efficacy and safety of nedaplatin-combination therapy (NDP/5-FU [5-FU arm] or NDP/S-1 [S-1 arm] ) for the treatment of oral squamous cell carcinoma.

PATIENTS AND METHOD

Previously non-treated oral squamous cell carcinoma patients were eligible. Patients received 5-FU 600 mg/m(2)iv, as a 24-hour infusion (day 1 to 5) followed by NDP 80 to 100 mg/m(2) iv (day 1), or S-1 60 to 80 mg/m(2) orally twice a day (day 1 to 14) followed by NDP 80 mg/m(2) iv (day 8) every 28 days for one or two cycles.

RESULTS

In total, 32 patients (18 in the 5-FU arm, 14 in the S-1 arm) were enrolled. Twenty patients were male and 12 were female. Median age was 57 years (range 20 years to 87 years). Thirty-one patients had a performance status (PS) oF 0, and 1 patient had a PS 1. Three patients were stage I, 12 stage III, and 12 were stage IV. The overall response rate was 69% (5-FU arm,72%;S-1 arm,64%). Two patients achieved a complete response, 20 patients a partial response, and 10 patients had no change. Grade 3 leucopenia, grade 3 and 4 thrombocytopenia and liver injury occurred in 6% (one in the 5-FU arm, and one in the S-1 arm), 9% (two in the 5-FU arm, and one in the S-1 arm), and 3% (one in the 5-FU arm), respectively. No other severe toxicities were observed.

RESULTS

Response rate and toxicities were similar in both arms. However, the psychosocial stress on patients in the S-1 arm was reduced compared to that in the 5-FU arm, which required hospitalization for a longer period. The outcome in the present study needs further investigation.

Bone with a vascular flap induced from fat tissue with the use of rhBMP-2 in rats

Here we report that successful bone formation with a vascular flap inside a cylindrical mold was induced from fat tissue with the use of recombinant human bone morphogenetic protein-2 in rats. Fat tissue connected to blood vessels was prepared to fit into the mold and implanted intramuscularly into the hind leg in Wistar rats. RhBMP-2 (20 micro g) was applied in a collagen sheet previously placed on the inside surface of the mold. Bone formation was confirmed radiologically and morphologically at 2, 4, and 8 weeks after the surgery. In the control group without rhBMP-2 or the group with ligation of the blood vessels before the implantation, bone formation was not observed. Our success in bone formation having a definite size, shape, and blood supply may lead to a therapeutic approach to effective bone reconstitution. The present study is the first report on bone induction from fat tissue by rhBMP-2 in vivo.

[Combination chemotherapy with nedaplatin (CDGP) and 5-FU for oral cancer]

Chemotherapy using CDGP plus 5-FU was evaluated in patients with oral cancer. The subjects were patients with squamous cell carcinoma of the oral cavity who had not received any therapy, comprising 7 patients with carcinoma of the tongue, 2 with buccal carcinoma, 2 with maxillary gingival carcinoma, and 1 with carcinoma of the oral floor. There were 4 patients in Stage II, 3 patients in Stage III and 5 patients in Stage IV. Patients with a PS < or = 1, WBC > or = 4,000/mm3, Hb > or = 10 g/dl, platelet count > or = 10 x 10/mm3, and normal liver, kidney, and heart function at baseline were selected for this study. In all patients, 5-FU was administered at a dose of 600 mg/m2/day for 5 days (day 1 to day 5) by continuous infusion, for a total dose of 3,000 mg/m2. CDGP was administered on day 1 at a dose of 80 mg/m2 in 8 patients and at 100 mg/m2 in 4 patients. This treatment was one course of therapy, and patients received 1 or 2 courses. Of 12 patients who were evaluable, there were 9 partial responses and 3 no changes, for a major response rate of 75%. Toxicities experienced by patients were mild (grade 2 or lower) gastrointestinal disorders (including nausea/vomiting) and renal impairment, while grade 3 leukopenia and thrombocytopenia developed in 1 patient each and grade 4 thrombocytopenia occurred in another patient. Thus, patients receiving CDGP + 5-FU therapy should be closely monitored for hematologic toxicity. Since CDGP + 5-FU therapy achieved a good response rate (75%) in the treatment of squamous cell carcinoma of the oral cavity, we plan to use this therapy in the future and assess its benefit in a larger number of patients.

Blocking the glycine-binding site of NMDA receptors prevents the progression of ischemic pathology induced by bilateral carotid artery occlusion in spontaneously hypertensive rats

This study was designed to investigate the participation of N-methyl-D-aspartate (NMDA) receptors in the progression of the pathology induced by bilateral carotid artery occlusion (BCAo) in spontaneously hypertensive rats (SHRs). We examined the effects of the selective NMDA receptor glycine-binding site antagonist SM-18400 on the mortality rate, deterioration of neurological signs, and formation of brain edema in the SHR-BCAo model. SM-18400 (15 or 30 mg/kg) was administered via the tail vein immediately and 2 h after BCAo. Neurological signs were monitored continuously for 8 h after BCAo, and the mortality rates were followed for 5 days. All SM-18400-treated animals were still alive 5 h after BCAo, whereas 38% of the animals died in the vehicle-treated group. The mortality rates of the SM-18400-treated groups were still lower than those of the vehicle-treated group 5 days after BCAo. In addition, SM-18400 markedly prevented the deterioration of neurological signs. The water content of the telencephalon and diencephalon/mesencephalon in the vehicle-treated group, measured 3 h after BCAo, was significantly higher than in the sham-operated group. SM-18400 significantly inhibited the increase in water content in both regions in a dose-dependent manner. These findings suggest that NMDA receptors participate in the increase in the mortality rate, deterioration of neurological signs, and formation of brain edema following ischemic brain damage in the SHR-BCAo model, and that SM-18400 can prevent ischemic insults.

Fusion variations of pancreatic ducts in patients with anomalous arrangement of pancreaticobiliary ductal system

Fusion variations of the pancreatic ducts were studied to elucidate the significance of such variations. We classified structural fusion anomalies of the main and accessory pancreatic ducts on endoscopic retrograde cholangio-pancreatography (ERCP) in 37 patients with anomalous arrangement of the pancreaticobiliary ductal system (AAPB). The fusion variations of the pancreatic ducts were classified into five types: common, ansa pancreatica, branch fusion, looped, and separated. These fusion variations, except for common type, were found in 68% of the 37 patients with AAPB on ERCP. Fusion variations of the pancreatic ducts were very frequent (93%) in the 30 patients with congenital cystic dilatation of the common bile duct (CCD). The branch confluence fashion, in which the terminal bile duct communicated with a pancreatic duct branch, was found only in patients with cystic dilatation cyst of the CCD, and it appeared that cystic dilatation cyst of CCD might differ from spindle or cylindrical cyst originating from embryonic formation of an anomalous confluence. It was also suggested that in patients with fusion variations of the pancreatic ducts, the flow of pancreatic juice might be disordered, leading to the development of acute pancreatitis or pancreatic dysfunction. Consequently, it appears to be necessary to carefully examine patients with AAPB for the presence or absence of any fusion variations of the pancreatic ducts and to observe such patients with long-term monitoring by ERCP, and computed temography, and with pancreatic function tests.

Comparison of the expression of three highly related genes, Fgf8, Fgf17 and Fgf18, in the mouse embryo

In mammals, 16 members of the Fgf family have so far been described with diverse roles in embryonic cell growth and differentiation. Here, we report the expression from early streak stage to midgestation of two newly-identified murine genes, Fgf17 and Fgf18, that are most closely related to Fgf8 (63.7% and 56.8% identical, respectively, at the amino acid level). Fgf17 is expressed during gastrulation but at lower levels than Fgf8, while Fgf18 RNA is not expressed until later, in paraxial mesoderm. In the developing tail bud, each Fgf gene shows a different pattern of transcription. Distinct and overlapping expression patterns are also described in the developing brain and limbs.

Characterization of two length cDNA for human MSX-2 from dental pulp-derived cells

Screening of a human dental pulp cells cDNA library with mouse Msx-1 and Msx-2 cDNA probes led to the isolation of human MSX-2. Sequence and Northern Blotting analysis revealed that two different type of transcripts due to the length of 3' untranslated region were expressed in the human dental pulp cells.

Effects of the novel tricyclic quinoxalinedione derivatives, SM-18400 and its analogs, on N-methyl-D-aspartate (NMDA) receptor-mediated synaptic transmission in the isolated neonatal rat spinal cord in vitro

We examined the effects of novel tricyclic quinoxalinedione derivatives, SM-18400 ((S)-9-chloro-5-[p-aminomethyl-o-(carboxymethoxy)phenylcarbamoylmethy l]-6,7-dihydro-1H,5H-pyrido[1,2,3-de]quinoxaline-2,3-dione hydrochloride trihydrate) and its analogs (i.e., ID-17263 and ID-17332), on the N-methyl-D-aspartate (NMDA) receptor-mediated polysynaptic reflex (PSR) in the isolated spinal cord of neonatal rats in vitro. Application of SM-18400 selectively suppressed the PSR activity in a concentration-dependent manner without affecting the monosynaptic reflex (MSR). Differential suppression of the PSR was also obtained with ID-17263, ID-17332 and other known NMDA receptor glycine-binding site antagonists, 5,7-dichlorokynurenate (5,7-diClkyn) and L-689,560 (4-trans-2-carboxy-5,7-dichloro-4-phenylaminocarbonylamino-1,2,3,4 -tetrahydroquinoline). Relative potencies of the test drugs for inhibition of the PSR were as follows: SM-18400 >> L-689,560 > ID-17332 > ID-17263 > 5,7-diClkyn. In addition, the inhibitory effects of SM-18400 on PSR were markedly antagonized by simultaneous application of D-serine, an agonist for NMDA receptor glycine-binding sites. These findings suggest that SM-18400 is a potent NMDA receptor glycine-binding site antagonist and blocks the NMDA receptor-mediated synaptic neurotransmission in the spinal cord in vitro.

Overexpression of bcl-2 protein inhibits terminal differentiation of oral keratinocytes in vitro

The bcl-2 proto-oncogene is a known inhibitor of apoptosis; in normal human stratified squamous epithelium, its expression is restricted to the basal cell layer. To investigate the functional role of bcl-2 protein in the process of differentiation of oral keratinocytes, bcl-2 expression vector was transfected into SCC-25 cells, which normally undergo squamous cell differentiation in vitro while expressing specific differentiation markers, e.g., keratin 10/11 and involucrin. In bcl-2 transfected SCC-25 cells, the expression of these differentiation markers was markedly suppressed. The bcl-2 proto-oncogene may play a critical role in opposing the commitment to terminal differentiation and apoptosis of oral keratinocytes.

Selective depression of the spinal polysynaptic reflex by the NMDA receptor antagonists in an isolated spinal cord in vitro

1. The effects of N-methyl-D-aspartate (NMDA) receptor glycine-binding site antagonists 7-chlorokynurenate (7-Clkyn) and (+/-)-3-amino-1-hydroxy-2-pyrrolidone (HA-966) on spinal reflexes in an isolated spinal cord that was maintained in Mg(2+)-free medium in vitro were examined. The actions of 7-Clkyn and HA-966 were compared with those of the channel-site antagonist (i.e., dizocilpine) and NMDA-binding site antagonists--that is, 3-[(+/-)-2-carboxypiperazin-4-yl]-propyl-1-phosphonate (CPP) and DL-2-amino-5-phosphonovalerate (APV). 2. 7-Clkyn and HA-966 produced a selective depression of the polysynaptic reflex (PSR) while negligibly affecting the activity of the monosynaptic reflex (MSR). The PSR was also differentially suppressed by dizocilpine, CPP and APV. The PSR inhibitory activity of the NMDA antagonists was in the following order: dizocilpine > CPP > APV = 7-Clkyn > HA-966. 3. The inhibitory effects of 7-Clkyn on PSR were markedly antagonized by the simultaneous application of D-serine, an agonist for the NMDA receptor glycine-binding sites. However, PSR inhibition by dizocilpine and CPP was unaffected. 4. Inhibition of the PSR by 7-Clkyn persisted in the presence of strychnine, which markedly increased the PSR activity by itself. 5. These findings suggest that the NMDA receptor glycine-binding sites play a role in generating the NMDA receptor-mediated PSR in the spinal cord in vitro.

Keratinocytes become terminally differentiated in a process involving programmed cell death

Oral keratinocytes originate from basal cells, differentiate during migration to the surface, and finally are shed. Apoptosis occurs at the end of differentiation, but the precise relationship between terminal differentiation and apoptosis is not clear. In the present study, Bcl-xL was expressed in the basal cell and spinous cell layers, and Bax was expressed in the spinous cell and granular cell layers. In cultured keratinocytes, Bcl-xL was expressed under conditions of 0.1 mM calcium (low Ca2+) but disappeared under conditions of 1.0 mM calcium (high Ca2+); the latter induces keratinocyte differentiation. Bax was not expressed in keratinocytes with low Ca2+ but was expressed in cells with high Ca2+. Finally keratinocytes with high Ca2+ underwent apoptosis, which was detected by the TUNEL method and by 180-bp DNA fragmentation. These results suggest that the process of terminal differentiation in gingival epithelium is a pathway to apoptosis.

Expression of mRNA encoding intestinal type alkaline phosphatase in rat liver and its increase by fat-feeding

The presence of types of alkaline phosphatase (ALP) other than the tissue non-specific type enzyme in rat liver and its increase by fat feeding are known. In order to examine expression of intestinal type ALP in liver, specific oligonucleotide primers corresponding to two types of mRNAs of rat intestinal ALP (RTIN-1 and -2) were designed and amplified by means of the reverse transcriptase-polymerase chain reaction (RT-PCR). It was found that RTIN-1 mRNA was expressed only in the intestine but not in the liver, while RTIN-2 mRNA was expressed both in the intestine and in the liver. By fat feeding, expression of RTIN-1 mRNA increased in the intestine and that of RTIN-2 mRNA increased both in the intestine and in the liver. Thus, it was concluded that rat liver expressed one of the intestinal type ALP (RTIN-2) which was enhanced by fat feeding.

Blood pressure response during dental surgery

To investigate blood pressure and pulse rate responses to dental surgery, 21 patients 18 to 73 years of age (mean age, 42 +/- 4 years) who visited our hospital for tooth extraction were studied. Before dental treatment, the patients underwent a mental arithmetic stress test, electrocardiography, and an anxiety evaluation with the State-Trait Anxiety Inventory. Baseline blood pressure and pulse rate were 118 +/- 4/70 +/- 3 mmHg and 69 +/- 2 beats/min, respectively. Blood pressure rose by 24 +/- 3/17 +/- 2 mmHg during the mental stress test, and the magnitude of the rise in systolic blood pressure was significantly correlated with age (r = 0.81, p < 0.001) and baseline blood pressure (r = 0.56, p < 0.01). After the topical injection of local anesthetic containing 1: 80,000 epinephrine, a transient increase in systolic blood pressure was observed. The maximum blood pressure and pulse rate increases during dental surgery were 24 +/- 4/13 +/- 2 mmHg and 17 +/- 3 beats/min, respectively. Similarly, the rate pressure product increased from 8,196 +/- 486 to 11,802 +/- 682. The magnitude of the blood pressure increase during dental surgery was not correlated with age, sex, family history of hypertension, baseline blood pressure, anxiety score, or response to mental stress. On the other hand, when the subjects were divided into two subgroups according to the blood pressure response during dental surgery, the larger response group (increase in mean blood pressure greater than 15 mmHg, n = 9) required a significantly larger dose of local anesthetic than did the smaller response group. The number of cases of pericoronitis of the third molar tended to be greater in the larger response group. These results indicate that an increase in blood pressure during dental surgery cannot be predicted on the basis of baseline blood pressure or the response to mental stress, but is related to the cause of tooth extraction and the volume of local anesthetics required to control the pain.

Production of functional human bone morphogenetic protein-2 using a baculovirus/Sf-9 insect cell system

A clone of a human Bone Morphogenetic Protein-2 (hBMP-2) cDNA was obtained from a cDNA library established from human dental pulp cells. After subcloning hBMP-2 cDNA into Autographa californica nuclear polyhedrosis virus, the recombinant baculovirus was transfected to Sf-9 cells. Immuno-reactive recombinant hBMP-2 (rhBMP-2) was detected by a polyclonal antibody against Xenopus BMP-2 in the transfected insect cells but not in the culture media. Three days after treatment with the lysate of the transfected Sf-9 cells, increase in alkaline phosphatase activity of a murine stromal cell line, ST2, was detected. Subcutaneous implantation of rhBMP-2 produced in the insect cells induced formation of cartilage, bone and bone marrow in the rats. The present data indicated that the rhBMP-2 preparation produced in the insect Sf-9 cells had a comparable activity to that produced in mammalian cells.

Cloning and sequence of bone morphogenetic protein 4 (BMP-4) from a human placental cDNA library

A cDNA clone encoding bone morphogenetic protein-4 (BMP-4) has been isolated from a human placental cDNA library. Sequence analysis of this clone revealed that the nucleotide sequence of 5' region was different from that of human osteosarcoma BMP-4 and the deduced amino acid sequence indicated deletion of N-terminal 6 amino acids. We confirmed the expression of this type of BMP-4 mRNA in one human osteogenic cell line in addition to the placenta by the polymerase chain reaction (PCR).

Identification of bone-type alkaline phosphatase mRNA from human periodontal ligament cells

Tissue-nonspecific-type alkaline phosphatase is found in the bone, liver, kidney, and other tissues, and its gene consists of 12 exons with the coding sequence beginning in the second exon. Recently, an alternative noncoding first exon was identified in the liver message which differed from that of the previously known osteoblast-derived cDNA sequence. Although these two mRNAs produce an identical protein, they have different promoter regions. The periodontal ligament tissue expresses a high level of alkaline phosphatase activity. To identify its mRNA type, we isolated a full-length cDNA for alkaline phosphatase from a cultured human periodontal ligament cell expression library, using bone-derived tissue-nonspecific alkaline phosphatase cDNA as a hybridization probe. The size of this clone was 2.5 kb, and its 5' and 3' untranslated sequences were identical to those of the human tissue-nonspecific type isolated from osteoblastic cells but not to those of the liver type. In addition, the same fragments as in bone-derived tissue-nonspecific-type cDNA were detected by the treatment of the cDNA clone with restriction enzymes Hinc II and Pst I. The results suggest that expression of the same alkaline phosphatase isozyme in human periodontal ligament cells may be regulated by the same transcriptional mechanism as in bone.

Molecular cloning and sequence of bovine Msx-1 homeobox-containing gene cDNA from a bovine odontoblast library

Screening of a bovine odontoblast cDNA library from developing incisor with murine Msx-1 and Msx-2 cDNA probes led to the isolation of three positive clones. All of them encoded for a sequence of a protein containing 297 amino acids. The responsible gene was designated as bovine Msx-1 (bMsx-1) due to the high homology with the human MSX-1 and mouse Msx-1 sequences.

Modulation of responses to TGF-beta by 1, 25 dihydroxyvitamin D3 in MG-63 osteoblastic cells: possible involvement of regulation of TGF-beta type II receptor

The effect of TGF-beta 1 on the expression of alkaline phosphatase (ALPase) activity was examined during osteoblastic cell line (MG-63) differentiation induced by 1,25-dihydroxyvitamin D3 (1,25D3). TGF-beta 1 and 1,25D3 were found to enhance ALPase activity. However, preincubation of the cells with 1,25D3 transiently abolished the effects of TGF- beta 1. Kinetics of the complex responses to TGF- beta 1 and 1,25D3 were found to correlate well with that of the expression level of type II receptor for TGF- beta. These results suggest that 1,25D3 may regulate the cellular responses to TGF- beta 1 in part via regulation of functional receptor for TGF- beta.

Molecular cloning of rat bone morphogenetic protein (BMP) type IA receptor and its expression during ectopic bone formation induced by BMP

A cDNA for the rat bone morphogenetic protein (BMP) type IA receptor (BMPR-IA) was isolated from a dental pulp cell cDNA library. The rat BMPR-IA cDNA encodes a protein of 532 amino acids with a single transmembrane domain and a putative serine/threonine kinase domain. The overall amino acid sequence identity between the rat and human BMPR-IA was 97%. Reverse transcriptase-polymerase chain reaction analysis revealed that BMPR-IA mRNA was highly expressed in the BMP-induced bone forming tissues throughout the stages tested.

Expression of bone morphogenetic protein genes in the human dental pulp cells

Dental pulp has a potential to induce ectopic bone formation, but little is known about its mechanism. We thought that bone morphogenetic proteins (BMPs), members of the transforming growth factor-beta (TGF-beta) superfamily, are involved in the osteoinductive activity of dental pulp. In order to prove this assumption, we constructed a cDNA library from primary culture cells of human dental pulp (HDP cells), and screened the library with previously cloned cDNAs for mouse BMP-2 and -6 as probes. Three distinct cDNA clones encoding human BMP-2, -4 and -6 were isolated. By Northern blot analysis, specific transcripts of the genes of those BMPs were detected in the HDP cells. It was concluded that the BMPs were expressed in a certain population of dental pulp cells and might play some roles in ectopic bone formation by dental pulp.

Changes in homeobox-containing gene expression during ectopic bone formation induced by bone morphogenetic protein

Expression of homeobox genes in relation to ectopic bone formation induced by bone morphogenetic protein (BMP) was investigated. Oligonucleotide primers corresponding to highly conserved regions of Hox cluster and Msx genes were designed to detect homeobox sequences by means of the polymerase chain reaction (PCR). Nine rat homologues of Hox cluster genes and two Msx genes were discovered in the BMP-implanted tissue, at earlier stage and later cartilage and bone formation stage, respectively. The PCR study provided evidence of dynamic changes in BMP-induced homeobox gene expression.

Effects of SM-9018, a potential atypical neuroleptic, on the central monoaminergic system in rats

The effects of SM-9018, a potential atypical neuroleptic, on monoamine metabolism were studied in rats. SM-9018 dose-dependently increased the levels of 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) in the cerebral cortex and striatum without affecting the levels of 5-HT, norepinephrine and their metabolites. This action persisted for 8 hr with a maximum effect at 1-2 hr. The SM-9018-induced increase of dopamine (DA) turnover, as indexed by HVA/DA and DOPAC/DA ratios, was comparable in the cerebral cortex and striatum, whereas the typical neuroleptic haloperidol preferentially enhanced the striatal DA turnover. These findings suggest that SM-9018, unlike haloperidol, increases DA turnover to a similar extent both in the cerebral cortex and striatum.

Excitatory amino acid receptor binding in hippocampus of gerbils with transient global brain ischemia

Binding of a variety of ligands for brain excitatory amino acid receptors was examined in membrane preparations extensively washed and treated with Triton X-100 that were obtained from the hippocampus and cerebral cortex of gerbils that survived for different periods after transient global brain ischemia. Bilateral occlusion of the carotid arteries for 5 min did not affect the binding of [3H](+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imi ne (MK-801) to an open ion channel associated with the N-methyl-D-aspartate (NMDA)-sensitive subclass in both central structures of gerbils that survived for 1 to 4 weeks after the injury when determined at equilibrium in the presence of 3 different endogenous agonists including L-glutamic acid (Glu), glycine (Gly) and spermidine at maximally effective concentrations. In contrast, the ischemic occlusion significantly diminished [3H]MK-801 binding when determined before equilibrium in the presence of the 3 stimulants in hippocampal membranes without altering that in cortical membrane 2 weeks after the insult, so that the initial association rates were invariably reduced by more than 60%. Moreover, the occlusion not only reduced the binding of both [3H]Glu and [3H]D,L-(E)-2-amino-4-propyl-5-phosphono-3-pentenoic acid to the NMDA domain on the NMDA receptor ionophore complex, but also decreased the binding of both [3H]Gly and [3H]5,7-dichlorokynurenic acid to the Gly domain. However, the insult did not induce any detectable changes under the experimental conditions employed in either the binding of [3H]DL-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) to the AMPA-sensitive subclass or the binding of kainic acid (KA) to the KA-sensitive subclass in both central regions of animals that survived for 2 weeks. These results suggest that transient global brain ischemia may predominantly impair neuronal and/or glial cells enriched of the NMDA receptor ionophore complex in gerbil hippocampus.

Impaired coronary blood flow response to acetylcholine in patients with coronary risk factors and proximal atherosclerotic lesions

We examined whether coronary risk factors and atherosclerotic lesions in the study artery were associated with impaired endothelium-dependent dilation of coronary resistance arteries. Acetylcholine (ACH) at graded doses (1, 3, 10 and 30 micrograms/min) and papaverine (10 mg) were selectively infused into the left anterior descending coronary artery of 28 patients, in whom the study artery was angiographically normal (n = 16) or with mild stenosis < or = 40% (n = 12). Coronary blood flow (CBF) was estimated from the product of mean CBF velocity measured by an intracoronary Doppler catheter and the arterial cross-sectional area of the study artery determined by quantitative arteriography. ACH increased CBF in a dose-dependent manner. However, the maximum CBF response to ACH varied widely among patients (from 50% to 660%). By multivariate analysis, the presence of atherosclerotic lesions in the study artery was an independent predictor for impaired CBF response to ACH (P < 0.01). Hypertension (P < 0.001), hypercholesterolemia (r = -0.52, P < 0.005), age > or = 50 yr (P < 0.01) and total number of coronary risk factors (r = -0.62, P < 0.001) were associated with the impaired increase in CBF with ACH by univariate analysis. The percent increase in CBF evoked with papaverine did not correlate with these risk factors. The results suggest that mild atherosclerotic lesions in the study artery and coronary risk factors are accompanied by impaired endothelium-dependent dilation of coronary resistance arteries evoked with ACH. Endothelial dysfunction of coronary resistance arteries may result in altered regulation of myocardial perfusion in patients with mild coronary atherosclerosis and coronary risk factors.

Determination of catecholamines and their metabolites in adrenals of stress-loaded and wild suncus (Suncus murinus)

The contents of catecholamines and their metabolites were measured in the adrenals of 3 groups of suncus. The first group was naive housed suncus; the second, suncus with stress-loading; and the third, wild ones. There were no significant differences in dopamine, norepinephrine and normetanephrine levels among the control, stress and wild groups. The content of epinephrine, however, decreased in the stress and wild group to 57% and 18%, respectively. These results suggest that housed suncus can easily react to stressful circumstances.