Recombinant human bone morphogenetic protein-2 potentiates the in vivo osteogenic ability of marrow/hydroxyapatite composites

A composite of marrow mesenchymal stem cells (MSCs) and porous hydroxyapatite (HA) has bone-forming capability. To promote the capability, we added recombinant human bone morphogenetic protein-2 (BMP) to the composite. The bone formation was assessed by rat subcutaneous implantation of 4 different kinds of implants, i.e., HA alone, BMP/HA composites, MSCs/HA composites, and the composites containing BMP (MSCs/BMP/HA). Both HA and the BMP/HA composites did not show bone formation at any time after implantation. The MSCs/HA composites showed moderate bone formation at 4 weeks and extensive bone formation at 8 weeks. The MSCs/BMP/HA composites showed obvious bone formation together with active osteoblasts at 2 weeks and more bone formation at 4 and 8 weeks. The MSCs/BMP/HA composites demonstrated high alkaline phosphatase and osteocalcin expression at both the protein and gene levels. These results indicate that the combination of MSCs, porous HA, and BMP synergistically enhances osteogenic potential and provides a rational basis for their clinical application in bone reconstruction surgery.

Enhancement of the in vivo osteogenic potential of marrow/hydroxyapatite composites by bovine bone morphogenetic protein

A composite of marrow mesenchymal stem cells and porous hydroxyapatite (HA) has in vivo osteogenic potential. To investigate factors enhancing the osteogenic potential of marrow/HA composites, we prepared a bone morphogenetic protein (BMP) fraction from the 4M guanidine extract of bovine bone by heparin-sepharose affinity chromatography. Marrow/HA composites or composites containing marrow mesenchymal stem cells, BMP, and HA (marrow/BMP/HA composites) were implanted subcutaneously in 7-week-old male Fischer rats. BMP/HA composites and HA alone were also implanted. The implants were harvested after 2, 4, or 8 weeks and were prepared for histological and biochemical studies. Histological examination showed obvious de novo bone formation together with active osteoblasts at 2 weeks, as well as more extensive bone formation at 4 and 8 weeks in many pores of the marrow/BMP/HA composites. The marrow/HA composites did not induce bone formation at 2 weeks, but there was moderate bone formation at 4 weeks. At 2 weeks, only marrow/BMP/HA composites resulted in intensive osteogenic activity, judging from alkaline phosphatase and osteocalcin expression at both the protein and gene levels. These results indicate that the combination of marrow mesenchymal stem cells, porous HA, and BMP synergistically enhances osteogenic potential, and may provide a rational basis for their clinical application, although further in vivo experiment is needed.

Magnesium removal impairs the regulatory role of rat endothelium

Vascular endothelium has been shown to play an important role in the regulation of vascular tone and, hence, impairment of the endothelium may induce hypertension. Although magnesium (Mg) deficiency could induce hypertension, the role of Mg on the endothelium is unclear. We examined the effects of Mg removal on endothelium-dependent and -independent responses using ring preparations of femoral arteries obtained from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Norepinephrine (10(-9)-10(-4) M) evoked concentration-dependent contractions in arteries with endothelium. The maximal response was greater in SHR than in WKY. Removal of external Mg augmented the contraction in WKY but not in SHR. As a result, the contraction obtained in arteries with endothelium was identical in the two groups. Removal of the endothelium enhanced the contraction in both strains, with a greater response occurring in WKY than in SHR in Krebs, but not in Mg-free, solution. As a result, in arteries without endothelium, the contractions were identical in WKY and SHR both in Krebs and Mg-free solutions. Acetylcholine (10(-9)-10(-4) M) evoked concentration-dependent relaxation in arteries with, but not in those without, endothelium obtained from WKY and SHR. The relaxation did not differ between the two strains, nor was it altered by Mg removal. Thus, Mg removal impairs inhibitory function of the endothelium against contraction induced by norepinephrine, without affecting endothelium-dependent relaxation in response to acetylcholine, in the rat femoral artery. The effect of Mg removal is not apparent in SHR. The fact that after removal of external Mg the contraction in response to norepinephrine in arteries with endothelium is identical in WKY and SHR suggests that a normotensive artery with Mg deficiency may mimic a hypertensive artery through endothelial impairment.

In vivo gene gun-mediated transduction into rat heart with Epstein-Barr virus-based episomal vectors

BACKGROUND

Gene guns have been used to transfer genes into various organs, but there has been no report of successful gene gun-mediated gene transfer into the heart. In this study, we assessed the possibility of gene therapy using a gene gun and an episomal plasmid vector.

METHODS

Gene transfer was performed using two sizes of gold particles and two plasmids (an episomal vector and a conventional plasmid vector). From the first to eighth week after the bombardment, rats were sacrificed. The excised hearts were subjected to X-gal staining and histologic examination. To ensure that plasmid was not distributed to organs other than the heart, the presence of the beta-gal sequence was examined by polymerase chain reaction analyses.

RESULTS

Gene expression persisted for 6 weeks. The episomal vector apparently contributed to long-lasting expression. Infiltration of monocytes or leukocytes was very faint. The beta-gal DNA was detected in bombarded hearts but not other organs.

CONCLUSIONS

Gene gun-mediated transfer of the episomal vector into beating heart may provide a simple, efficient, and useful strategy for gene therapy.

Failure of L-arginine to induce hypotension in patients with a history of accelerated-malignant hypertension

A profound elevation of blood pressure on exercises or after withdrawal of antihypertensive drugs has been reported in patients with a history of accelerated-malignant hypertension. We tested the hypothesis that severe endothelial dysfunction is responsible for the profound hypertensive response in these patients. Responses of blood pressure, heart rate and plasma cyclic guanosine monophosphate to intravenously infused L-arginine, a precursor of nitric oxide, was investigated in hypertensive patients with (group A) or without any history of accelerated-malignant hypertension (group B) in order to evaluate endothelial function. Casual blood pressure or severity of hypertension was not different between group A and B. Infusion of L-arginine decreased mean blood pressure in group B (97.4 +/- 8.7 to 81.7 +/- 6.9 mm Hg), but not in group A (99.0 +/- 10.2 to 101.5 +/- 8.7 mm Hg). Plasma levels of cyclic guanosine monophosphate were increased after infusion of L-arginine in group B (5.4 +/- 2.0 to 7. 7 +/- 1.7 pmol/ml, P< 0.01), while no significant changes were observed in group A (5.4 +/- 2.1 to 5.9 +/- 2.1 pmol/ml). There was a significant correlation between decrease in mean blood pressure and increase in plasma levels of cyclic guanosine monophosphate (r = 0.83, P < 0.001). The results indicated that much more severe endothelial dysfunction is present in hypertensive patients with a history of accelerated-malignant hypertension as compared to those without the history. The difference in the endothelial function may account for the different pressor responses to exercises or other stimuli observed in hypertensive patients with and without a history of accelerated-malignant hypertension. Journal of Human Hypertension (2000) 14, 485-488

Long-term effect of antihypertensive therapy with calcium antagonist or angiotensin converting enzyme inhibitor on serum nitrite/nitrate levels in human essential hypertension

Endothelial function is impaired in hypertension. In the present study the effects of long-term antihypertensive therapy on endothelial production of nitric oxide (NO) were investigated. Fifteen untreated mild to moderate essential hypertensive patients and 13 normotensive subjects were enrolled in this study. Blood pressure, heart rate, lipid profiles, cyclic guanosine 3', 5'-monophosphate (cGMP) and nitrite/nitrate (NOx), which are stable metabolites of NO, were measured. The hypertensive patients were treated with a calcium antagonist, benidipine (CAS 91559-74-5) (Ca group: n = 8) or an angiotensin converting enzyme inhibitor, trandolapril (CAS 87679-37-6) (ACEI group: n = 7) and 12 weeks after the treatment the same examinations were performed. NOx and cGMP levels in hypertensive patients were significantly lower than those in normotensive subjects (32.3 +/- 4.1 versus 49.0 +/- 6.5 mumol/l and 2.16 +/- 0.39 versus 3.39 +/- 0.42 pmol/ml, respectively). Both antihypertensive agents decreased the elevated blood pressure (mean blood pressure; 120 +/- 3 to 99 +/- 3 mmHg in Ca group and 117 +/- 4 to 104 +/- 4 mmHg in ACEI group) and normalized the decreased NOx and cGMP levels (29.1 +/- 6.2 to 46.2 +/- 8.6 mumol/l and 1.96 +/- 0.37 to 3.20 +/- 0.71 pmol/ml in Ca group, 36.0 +/- 5.3 to 54.7 +/- 6.9 mumol/l and 2.45 +/- 0.52 to 2.87 +/- 0.43 pmol/ml in ACEI group, respectively). Either benidipine or trandolapril improves the endothelial function and increases the impaired basal release of NO in hypertension. This suggests the beneficial effects of the drugs on protection against the vascular complications in hypertension.

In vivo osteogenic capability of cultured allogeneic bone in porous hydroxyapatite: immunosuppressive and osteogenic potential of FK506 in vivo

Fischer or ACI rat marrow cells were obtained from femoral shafts and were cultured to confluence in Eagle's minimal essential medium (EMEM) supplemented with 15% fetal bovine serum. After trypsinization, the cells were subcultured on porous hydroxyapatite (HA; Interpore 500) blocks in the presence of beta-glycerophosphate and 10 nM dexamethasone (Dex). After 2 weeks of subculture, a mineralized bone matrix with osteogenic cells developed on the HA pore surfaces. ACI or Fischer cultured bone tissue/HA constructs were implanted subcutaneously into the backs of Fischer rats and the immunosuppressant FK506 was given to the rats for 4 weeks. Implants were harvested 4 weeks and 8 weeks after insertion. At 4 weeks, the ACI constructs (allografts) showed high levels of osteogenic parameters (alkaline phosphatase [ALP] activity and osteocalcin content) and bone formation was observed together with active osteoblasts without obvious accumulation of inflammatory cells. At 8 weeks, active osteoblasts and progressive bone formation were still observed, while osteogenic parameters remained high and osteocalcin messenger RNA (mRNA) was detected. Without FK506 administration, the allografts showed neither bone formation nor osteocalcin mRNA and there were only trace levels of the osteogenic parameters. In the case of Fischer constructs (isografts), extensive bone formation was detected and all the osteogenic parameters were higher with FK506 than without FK506 at both 4 weeks and 8 weeks. These results indicate that cultured bone tissue/HA constructs possess a high osteogenic potential, even as allografts, and that FK506 not only has an immunosuppressive action, but also promotes bone formation.

[Cilostazol increased heart rate with improvement of activity of daily living in an elderly patient with sick sinus syndrome]

An 86-year-old man had a history of hypertension and had been treated with calcium antagonist but no medications that could reduce heart rate. As a 12-lead electrocardiogram showed sinus bradycardia, complete right bundle branch block and left anterior fascicular hemiblock on his first visit to our hospital on January 1998, he was admitted to our hospital for further examination and treatment. A 24-hour Holter electrocardiogram demonstrated a total number of 74,182 heartbeats per day with pauses (> 2.0 sec) of 187/day. Overdrive atrial pacing study and His bundle electrogram revealed a prolonged corrected sinus node recovery time (5.820msec at a stimulation rate of 130/min) and H-V conduction time (80msec) with normal A-H conduction time, respectively. We diagnosed these abnormalities as sick sinus syndrome (Rubenstein II). His activity of daily living score was 30 points by the Barthel index on the day of admission. Oral administration of orciprenaline sulfate (30 mg/day), a beta-adrenoceptor agonist, was initially chosen rather than implantation of a cardiac pacemaker to increase his heart rate since he did not have any symptoms due to bradycardia and he did not give us an informed consent for the implantation. Orciprenaline sulfate, however, failed to increase total heartbeats (73,079/day). Then, oral cilostazol (100 mg/day), a phosphodiesterase III inhibitor, was administered. After two weeks of the regimen total heart beats were increased (85,642/day) with no pauses. The increase in heart rate resulted in the improvement of his activity of daily living (Barthel index: 55 points). Cilostazol could be the first line medication for elderly patients with bradyarrhythmia in whom implantation of cardiac pacemaker is not absolutely indicated.

Osteogenic phenotype expression of allogeneic rat marrow cells in porous hydroxyapatite ceramics

Porous hydroxyapatite (HA) ceramics were combined with either allogeneic (ACI) or isogeneic (Fischer 344) rat marrow cells and implanted in subcutaneous sites of Fischer rats. FK506 as an immunosuppressant or saline was administered to the recipient rats. The implanted marrow/HA composites were harvested on day 28 and analyzed for bone-forming capability by determining osteoblastic phenotype expression levels of protein synthesis and gene expression. The alkaline phosphatase (ALP) activity and osteocalcin (OC) contents were very low and mRNAs (Northern blot analysis) were not detected in the allografts without FK506. However, high activity of ALP and high content of OC were found and mRNAs were detected in the allografts with FK506 and in the isografts (with and without FK506). This analysis indicates the osteogenic potential of allogeneic marrow cells in the presence of FK506. The histologic sections revealed that allografts without FK506 did not show bone formation but did show the infiltration of many small cells in the ceramics indicating an immunologic reaction, however, the allografts with FK506 and the isografts (with and without FK506) showed consistent de novo bone formation on the HA pore surface. These results indicate that FK506 can suppress the immunologic reaction in the allografts and induce a favorable conditions to support osteoblastic differentiation of allogeneic rat marrow stromal stem cells on the surface of HA ceramics. Therefore, our study suggests the feasibility of clinical transplantation of allogeneic bone marrow for a selected bone graft in applications using adjuvant systemic immunosuppression.

Al2O3 doped apatite-wollastonite containing glass ceramic provokes osteogenic differentiation of marrow stromal stem cells

Fresh marrow cells were obtained from femora of Fischer rats and cultured in a medium containing 15% fetal calf serum (FCS) until confluence. After trypsinization, cells were subcultured at a cell density of 100 x 10(3)/35-mm well in the presence of FCS, beta-glycerophosphate, and ascorbic acid phosphate on four different culture substrata. The period of subculture was 2 weeks; the substrata used were the culture dish, apatite-wollastonite containing glass ceramic (AW), hydroxyapatite coated AW (HA/AW), and Al2O3 doped AW (Al/AW). The HA coating was attained by the incubation of AW in simulated physiological solution. The glass matrix of AW and HA/AW contained MgO, CaO, P2O5, and SiO2; Al/AW contained Al2O3 in addition to these components. The subculture on Al/AW substratum showed many alkaline phosphatase (ALP) positive nodules and the highest ALP activity. On a Northern blot analysis the housekeeping gene of beta-actin mRNA was evenly detected from the cells cultured on all substrata; however, bone-specific osteocalcin mRNA was only detected from the cells on Al/AW. These results indicate that Al/AW provokes the osteoblastic differentiation of marrow stromal stem cells.

A novel polymorphism in the promoter region for the human osteocalcin gene: the possibility of a correlation with bone mineral density in postmenopausal Japanese women

We present a polymorphism of the human osteocalcin gene (also known as BGP, for bone Gla protein) due to a 1 base pair (bp) substitution from cytosine to thymine at position 298 nucleotides (nt), which is at position 198 nt upstream from the BGP exon 1. This mutation was detected by single-strand conformation polymorphism analysis after polymerase chain reaction for the osteocalcin gene fragment (326 bp) and sequencing analysis. The cytosine/thymine polymorphism can be defined by restriction fragment length polymorphism analysis using a modified primer pair and the restriction endonuclease HindIII. The osteocalcin genotype was determined in 160 postmenopausal Japanese women (age 48-80 years). Osteocalcin alleles were designated according to the absence (H) or presence (h) of the HindIII restriction site. There were 12 HH, 49 Hh, and 99 hh individuals, and the allele frequencies were 22.8% for H and 77.2% for h. To determine if genetic variation influences bone mineral density (BMD) and thus can be a determinant of susceptibility to osteoporosis in older women, we examined the association of BMD with the osteocalcin genotypes found in the present study. The subjects with genotype HH had the smallest BMD and those with hh had the greatest BMD among subjects, but these differences did not reach statistical significance. The HindIII genotype showed a significant effect on the prevalence of osteopenia in the subjects, that is, women with genotype HH had a 5.74 times greater risk for osteopenia (p < 0.05) and those with genotype Hh had a 1.59 times greater risk than women with genotype hh. We identified the osteocalcin gene polymorphism, detected with the HindIII genotype, which was suggested to influence bone density and is a possible genetic marker for bone metabolism.

Direct analysis of several Fusarium mycotoxins in cereals by capillary gas chromatography-mass spectrometry

A method for qualitative and quantitative analysis of Fusarium mycotoxins by gas chromatography-mass spectrometry (GC-MS) using cold on-column injection was improved. Eight typical mycotoxins, including deoxynivalenol (DON), 3-acetyldeoxynivalenol (3ADN), fusarenon-X (FX), diacetoxyscirpenol (DAS), 15-monoacetylscirpenol (15MAS), T-2 toxin (T-2), scirpentriol (SCT), and zearalenone (ZEA) were subjected to GC-MS without chemical derivatization by means of the on-column injection technique. Chromatographic separation of the toxins extracted from barley was achieved as a single peak, and the specific EI mass spectra of each toxin were obtained. The fatty acids in the extract that interfere with measurements of the toxins on the gas chromatogram were removed by precipitation as an insoluble metal soap with zinc acetate. Additional clean-up was accomplished using a Bond Elut Florisil cartridge. The quantitative detection limit in barley ranged from 0.1 to 0.5 micrograms/g. The average recoveries of 93.1% for DON, 3ADN, 15MAS, DAS, T-2 and ZEA, and 46.0% for FX and SCT added to barley at the level of 1 microgram/g were obtained.

[Clinical significance of serum lipoprotein(a) in elderly patients with aortic valve sclerosis]

BACKGROUND

Calcified aortic value disease is increasing with explosively in the elderly. Elevated serum lipoprotein(a) (Lp(a) plays an important role in the pathogenesis of atherosclerosis. Thus, we investigated the relationship between aortic valve sclerosis and serum Lp(a) levels in elderly patients.

METHODS

Echocardiography was performed in 97 subjects (77 +/- 7 years, 48 males and 49 females), Lp(a), fasting plasma glucose, and blood pressure were measured at the time of the study. Aortic valve sclerosis was assessed using echocardiography.

RESULTS

Aortic valve sclerosis was observed in 63 patients (sclerosis group; 24 males and 39 females) and not in 34 subjects (non-sclerosis group; 24 males and 10 females). Univariable analysis revealed that age, Lp(a) level, and the number of females were higher in the sclerosis group than in the non-sclerosis group (age; 78 +/- 7 vs 74 +/- 7 years, p = 0.0090, Lp(a); cholesterol, triglyceride, and fasting blood glucose did not seem to affect aortic valve sclerosis. In all of 9 patients with serum Lp(a) greater than 60mg/dl aortic valve sclerosis was present. In discriminative analysis, gender (female) (lambda = 0.9038, p = 0.0020) and Lp(a) (lambda = 0.8316, p = 0.0053) were related to aortic valve sclerosis.

CONCLUSION

Elevated serum Lp(a) was observed in elderly patients with aortic valve sclerosis.

Heterogeneous pattern of gene expression in cloned cell lines established from a rat transplantable osteosarcoma lung metastatic nodule

We have established three cloned cell lines (COS1NR, COS2NR and COS4NR) from the lung metastatic nodule of a highly metastatic variant of rat transplantable osteosarcoma, C-SLM. All three clones shared the same morphological characteristics and tumorigenicity, but their growth rates in vitro and metastatic ability in vivo differed from each other. Single-strand conformation polymorphism (SSCP) analysis revealed all three clones to have the same p53 gene mutation and parent C-SLM tumor. On the other hand, Northern blot analysis showed a different pattern of expression for the genes, c-fos, c-jun, c-Ha-ras, transin (rat stromelysin), bone Gla protein (osteocalsin) and nm23/NDP kinase. These results indicate the presence of a heterogeneous cell population in terms of the different pattern of gene expression in a lung metastatic nodule of rat osteosarcoma and the present newly established cell lines will be useful for further investigation of the biological behavior of osteosarcomas.

Acute antihypertensive effects of calcium channel blockers are not affected by calcium supplementation in patients with essential hypertension

The study was designed to investigate whether the acute antihypertensive effects of calcium channel blockers are affected by calcium supplementation in patients with essential hypertension. The antihypertensive effects of calcium channel blockers (oral manidipine or intravenous nicardipine) were studied before and during calcium supplementation (1200 mg/day for 8 weeks) in 30 hospitalized patients with essential hypertension. The averages of systolic and diastolic blood pressure during a 24-hour period were not decreased by calcium supplementation. The acute antihypertensive effects of the calcium channel blockers nicardipine (0.25, 0.5, 1.5, 2.0 micrograms/kg/min, intravenous infusion) or manidipine (20 mg, once a day, orally) were not enhanced by calcium supplementation. Thus, calcium channel blockers can be safely combined with calcium supplementation in terms of blood pressure.

Infiltration of peroxidase-producing eosinophils into the lamina propria of patients with ulcerative colitis

Little information is available to explain the pathogenesis of ulcerative colitis (UC). In this study, we focused on eosinophils in the lamina propria of the mucosa of patients with UC in the active phase. Biopsy specimens were taken from 17 patients with UC in the active phase, 17 in the inactive phase, and 20 control patients, and submitted for histochemical staining for peroxidase and chloroacetate esterase for microscopic examination. Both peroxidase-producing and chloroacetate esterase-producing cells in the lamina propria increased markedly in the active phase (8.3 +/- 3.1/0.01 mm2 and 6.6 +/- 2.7/0.01 mm2, respectively), compared with values in the inactive phase (0.8 +/- 0.6/0.01 mm2 and 1.3 +/- 0.6/0.01 mm2) or in the controls (1.3 +/- 0.8/0.01 mm2 and 1.3 +/- 0.4/0.01 mm2). Triple staining for peroxidase, chloroacetate esterase, and nonspecific esterase in the specimens revealed that the peroxidase-producing cells constituted a different population from that of neutrophils, macrophages/monocytes, or basophils. A monoclonal antibody specific for eosinophil peroxidase stained almost all infiltrated peroxidase-producing cells. These results indicated that eosinophils with strong peroxidase activity had infiltrated the lamina propria in UC, suggesting an allergic background and the involvement of released peroxidase in the mucosal damage characteristic of UC.

Development of a simple and rapid elisa of urinary cotinine for epidemiological application

Highly stereospecific polyclonal antibodies (anti-CN) to cotinine (CN), a major metabolite of nicotine, were prepared from rabbit antisera to CN-linked keyhole limpet hemocyanin (KLH) by removing the antibodies to KLH and to its binding regions of CN. This was achieved by using immunoadsorbents consisting of insolubilized KLH onto CNBr-activated-Sepharose 4B. A new simple and rapid enzyme-linked immunosorbent assay (ELISA) of urinary CN was developed using the anti-CN. A brief outline of the method is as follows: CN-bovine thyroglobulin complex is coated onto wells of microtiter plates (1 ng/well), and then aliquots of urine samples or standard CN solutions were added followed by appropriate dilution of the anti-CN. The bound anti-CN antibodies are quantified spectrophotometrically with horseradish peroxidase-labelled anti-rabbit IgG and 2,2'-azino-di (3-ethylbenz- thiazoline)-6-sulfonic acid. Measurement of CN concentration in urine samples can be read off on a calibration curve drawn by using standard CN solutions. The standard curve ranged from 1 ng to 4 μ g /ml with an estimated lower limit of sensitivity of 7-8 ng/ml, resulting in within/between-assay CV (coefficient of variation) of lower than 10%. The method allowed one to assay more than 40 samples in duplicate by using just one plate, and is thus easily applicable to epidemiological investigations into exposure status to tobacco smoke.

Reliability of the electrocardiogram for detecting left ventricular hypertrophy in the elderly

In elderly people > or = 65 years old, QRS amplitudes in electrocardiograms correlated with left ventricular wall thickness, although the correlation decreased with advancing age. Simple voltage criteria for left ventricular hypertrophy are adequate, even in elderly people.

BMP-induced osteogenesis on the surface of hydroxyapatite with geometrically feasible and nonfeasible structures: topology of osteogenesis

Bone morphogenetic protein (BMP) is known to require a suitable carrier to induce ectopic bone formation in vivo. Hydroxyapatite ceramics have been reported to be effective in some forms but ineffective in others as a carrier of BMP-induced bone formation. In this study we compare three geometrically different forms of hydroxyapatite to examine their functions as carriers of BMP-induced bone formation. A fraction containing all the active BMPs (BMP cocktail) was partially purified from a 4M guanidine extract from bovine bone by a three-step chromatographic procedure. The BMP cocktail was combined with each of three forms of hydroxyapatite--solid particles (SPHAP), porous particles (PPHAP), and coral-replicated porous tablets (coral-HAP)--and implanted subcutaneously into rats. Both the PPHAP and coral-HAP systems induced osteogenesis 2 weeks after implantation, as evidenced by morphological and biochemical observations. Details of the osteogenetic process were followed by double-fluorescence labeling in the coral-HAP system to confirm bone formation on the surface of hydroxyapatite. However, there was no evidence of osteogenesis or chondrogenesis in the SPHAP system. The results indicate that the geometry of the interconnected porous structure in PPHAP and coral-HAP create spaces for vasculature that lead to osteogenesis while the smooth structure and close contact of particles in SPHAP inhibit vascular formation and proliferation of mesenchymal cells, preventing bone and cartilage formation. It was concluded that the geometrical structure in hydroxyapatite ceramics that induces vasculature is crucial as a carrier for BMP-induced bone formation.

Osteoblastic phenotype expression on the surface of hydroxyapatite ceramics

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

Occult extraadrenal pheochromocytoma treated as diabetes mellitus

Pheochromocytoma usually is associated with a combination of various manifestations caused by overproduction of catecholamines. We encountered a case of an occult, catecholamine-secreting pheochromocytoma. A 70-year-old man was admitted to the hospital because of anorexia. He had been treated for diabetes mellitus for 4 years; during this period he did not have any other symptoms related to pheochromocytoma. At admission, serum epinephrine, norepinephrine, and glucose levels and urinary excretion of total metanephrine were elevated. A tumor was detected in the left adrenal region and diagnosed as pheochromocytoma. After tumor resection, the increased levels of catecholamines and glucose and the decreased urinary C-peptide were normalized. This suggests that the pheochromocytoma caused hyperglycemia without other manifestations for a long time.

Osteoblastic phenotype expression on the surface of hydroxyapatite ceramics

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

Doppler echocardiographic evaluation of latent pulmonary hypertension by passive leg raising

BACKGROUND

The prevalence of chronic lung disease increases with advancing age. The purpose of this study was to detect latent pulmonary hypertension noninvasively in elderly patients with chronic lung disease.

METHODS

The changes of flow-velocity by passive leg raising were assessed using pulsed Doppler echocardiography in the right ventricular outflow tract in 19 patients with chronic lung disease and 13 normal healthy subjects. Pulmonary artery pressure was measured simultaneously using a thermodilution cardiac output catheter.

RESULTS

In patients with chronic lung disease examined at rest, we found pulmonary hypertension in seven, and none in 12. The normal pattern observed at rest changed to pulmonary hypertension pattern after leg raising in six out of the 12 patients. Pulmonary arterial catheterization confirmed the data obtained by pulsed Doppler echocardiography.

CONCLUSIONS

Some elderly patients with chronic lung disease have latent pulmonary hypertension which can be detected noninvasively by analyzing the changes of flow velocity profiles in the right ventricular outflow tract by passive leg raising.