Antihypertensive effect of a proteasome inhibitor in DOCA-salt hypertensive rats

To search for a possible role for vascular proteasome in hypertension, we examined changes in proteasome level in aorta of deoxycorticosterone acetate (DOCA)-salt hypertensive rats and evaluated the antihypertensive effect of a proteasome inhibitor, N-benzyloxycarbonyl-Ile-Glu(O-t-Bu)-Ala-leucinal (PSI). Two weeks after the start of DOCA-salt treatment, the rats, with systolic blood pressure being 154 +/- 5 mmHg, were randomly divided into two groups and were given PSI or its vehicle for 2 weeks. Vehicle-treated DOCA-salt rats developed marked hypertension after 4 weeks (198 +/- 9 mmHg), with increases in aortic proteasome activity and content. The systolic blood pressure was positively correlated with both the content and activity of aortic proteasome. The administration of PSI to DOCA-salt hypertensive rats suppressed the elevation of systolic blood pressure (144 +/- 4 mmHg), accompanied by decreases in aortic proteasome activity and content. These results suggest that proteasome production in vascular tissues is increased in DOCA-salt hypertensive rats, and that PSI exhibits antihypertensive effect in this experimental hypertensive model. Thus, the findings indicate the pathophysiological importance of increased vascular proteasome in the development of DOCA-salt hypertension.

Soluble Fas mRNA is dominantly expressed in cases with silicosis

Although it is well known that cases with silicosis exhibit various immunological abnormalities, the mechanisms involved in the occurrence of immuno-dysfunction or dysregulation induced by silica compounds have not yet been determined. Fas is a well-known cell surface molecule that is involved in the apoptosis pathway that belongs to the tumour necrosis factor-receptor family. Soluble Fas (sFas) is produced as an alternatively spliced product of the Fas gene and protects cells from apoptosis due to antagonization of the binding between membrane form of the Fas gene (mFas) and the Fas ligand. To determine the role of the Fas/Fas ligand system in silica-induced immunological abnormalities, we investigated Fas and Fas-ligand message expression levels using the multiplex reverse transcription-polymerase chain reaction (RT-PCR) method with peripheral blood mononuclear cells from silicosis cases with no clinical symptoms of autoimmune diseases. Although the relative expression levels of the Fas or Fas-ligand genes were not remarkably altered in these cases, we observed the sFas message was dominantly expressed compared with mFas expression. These results suggest that self-recognizing clones in cases with silicosis survive for decades, escaping the exclusion mechanisms induced by apoptosis. Then they cause the appearance of autoantibodies and the acquisition of autoimmune diseases sequentially.

Endothelin-1 enhances pressor responses to norepinephrine: involvement of endothelin-B receptor

We investigated the effects of endothelin-1 (ET-1) on pressor responses to norepinephrine (NE) in perfused rat mesenteric arteries. Perfusion of the arteries with a subpressor dose of ET-1 (3 x 10(-10) M) for 15 min markedly enhanced the pressor responses to NE (10(-6) and 3 x 10(-6) M), and this effect was significantly prevented by BQ788 (10(-6) M) but not by FR139317 (10(-6) M). In DOCA-salt hypertensive rats, exogenous ET-1 had little effect on pressor responses to NE. Pressor responses to NE (10(-6) M) were significantly increased in DOCA-salt rats compared with those in normotensive rats. This increased response to NE was reduced to the level of normotensive rats by BQ788. FR139317 was without effect on the increased responses. These results suggest that ET-1 enhances contractile responses to NE through ETB receptors. Moreover, this phenomenon is stimulated tonically by endogenous ET-1 in DOCA-salt hypertensive rats and may contribute to the maintenance of hypertension in these rats.

Antihypertensive effect of sesamin. III. Protection against development and maintenance of hypertension in stroke-prone spontaneously hypertensive rats

The antihypertensive effect of sesamin, a lignan from sesame oil, was examined using salt-loaded and unloaded stroke-prone spontaneously hypertensive rats (SHRSP). The animals at 6 weeks of age were separated into a salt-loaded group and an unloaded group. Salt-loaded animals were maintained on 1% NaCl drinking water. Each group was further divided into two groups: normal-diet group and sesamin-diet group. Systolic blood pressure of all animals was monitored once weekly. At the end of the feeding periods, cardiovascular hypertrophy and renal damage were evaluated. In the salt-loaded group, sesamin feeding significantly suppressed the development of hypertension, and efficient suppression was maintained from 9 to 26 weeks (e.g., 215+/-4 vs. 180+/-4 mmHg, at 17 weeks old). The left ventricle plus septum weight-to-body weight ratio was slightly but significantly lowered by sesamin feeding. When the degree of vascular hypertrophy of the aorta and superior mesenteric artery was histochemically evaluated, wall thickness and wall area of these vessels were significantly decreased by the sesamin feeding. Histological renal damage such as thickening of the tunica intima and fibrinoid degeneration of the arterial wall were often observed in the normal-diet group, but this damage was efficiently reduced in the sesamin-fed animals. On the other hand, in the salt-unloaded group, only a slight and nonsignificant suppressive effect of sesamin on the development of hypertension was observed. Although the wall area of the aorta was significantly decreased by the sesamin feeding, other vascular parameters were not ameliorated. The incidence of histological renal damage tended to decrease in sesamin-fed animals, but these alterations were not statistically significant. Thus, sesamin feeding was much more effective as an antihypertensive regimen in salt-loaded SHRSP than in unloaded SHRSP, thereby suggesting that sesamin is more useful as a prophylactic treatment in the malignant status of hypertension and/or hypertension followed by water and salt retention.

Effects of acute or prolonged administration of cabergoline on parkinsonism induced by MPTP in common marmosets

The effects of a single treatment or chronic administration of cabergoline (1-[(6-allylergolin-8beta-yl)carbonyl]-1-[3-(dimethylamino)p ropyl]-3-ethyl-urea), a potent, long-lasting dopamine receptor agonist, on parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in common marmosets were studied. The administration of 0.2 mg/kg or a higer dose of cabergoline began to reverse parkinsonism-like symptoms 60 min after a subcutaneous injection, and showed steady and constant effects throughout the observation period. For prolonged administration, 0.2 mg/kg cabergoline was injected daily for 22 consecutive days. Locomotor activity in MPTP-treated animals increased until it reached its peak on the third day, then it gradually decreased. Akinesia scores, rating the quality of movements, were also improved, and the improvement was sustained up to the last day of chronic administration. None of the animals developed abnormal behaviors after either acute or chronic administration. These results suggest that cabergoline has long-acting effects in the marmoset model of parkinsonism, and that it will be a useful agent for the treatment of Parkinson's disease, particularly in cases with fluctuating motor disabilities.

Effects of endothelin-1 on norepinephrine-induced vasoconstriction in deoxycorticosterone acetate-salt hypertensive rats

We investigated the effects of endothelin-1 on pressor responses to norepinephrine in perfused mesenteric arteries of deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The response to norepinephrine (10(-6) M) was significantly increased in DOCA-salt rats compared with that in uninephrectomized control rats. Perfusion of the arteries with subpressor dose of endothelin-1 (3 x 10(-10) M) for 15 min markedly enhanced the pressor responses to norepinephrine (10(-6) and 3 x 10(-6) M) in control rats and this effect was significantly prevented by BQ788 [N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D -1-methoxycarbonyl-tryptophanyl-D-norleucine] (10(-6) M), but not by FR139317 ((R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1H-azepinyl)]carbonyl]amino-4-+ ++methylpentanoyl]amino-3-[3-(1-methyl-1H-indoyl)]propionyl]ami no-3-(2-pyridyl)propionic acid) (10(-6) M). In DOCA-salt hypertensive rats, increased pressor response to norepinephrine was declined to the level of control rats by BQ788, but not by FR139317. In contrast to the case seen with control rat, exogenous endothelin-1 had little effect on pressor responses to norepinephrine in the arteries of DOCA-salt hypertensive rats. Total immunoreactive endothelin content in the arteries of DOCA-salt hypertensive rats was significantly higher than that of uninephrectomized control rats. These results suggest that endothelin-1 enhances contractile responses to norepinephrine through endothelin ETB receptor. Moreover, this phenomenon is stimulated tonically by endogenous endothelin-1 in DOCA-salt hypertensive rats and may contribute to the maintenance of hypertension in DOCA-salt rats.

Novel non-peptide fibrinogen receptor antagonists. 1. Synthesis and glycoprotein IIb-IIIa antagonistic activities of 1,3,4-trisubstituted 2-oxopiperazine derivatives incorporating side-chain functions of the RGDF peptide

Based on the lead tetrapeptide RGDF, two possible non-peptide glycoprotein (GP) IIb-IIIa antagonists possessing an (S)-2-oxopiperazine-3-acetic acid moiety as a scaffold incorporating the indispensable Asp fragment were prepared, and (S)-4-[[trans-[4-(guanidinomethyl)-cyclohexyl]carbonyl]glycyl]-2- oxopiperazine-1,3-diacetic acid, 1a, was identified as a potential lead. A series of 3-substituted 2-oxopiperazine-1-acetic acids bearing the Arg-Gly equivalent at the 4-position were prepared and evaluated for their ability to prevent platelet aggregation and for their binding affinity for the GP IIb-IIIa receptor purified from human HEL cells. (S)-4-[(4-Amidinobenzoyl)glycyl]-3-[(methoxycarbonyl)methyl]- 2-oxopiperazine-1-acetic acid, 9 (TAK-029), inhibited in vitro human platelet aggregation with an IC50 value of 0.03 microM and GP IIb-IIIa-fibrinogen binding with an IC50 value of 0.49 nM. The [4-(2-aminoethyl)benzoyl]glycyl derivative 26 showed activity comparable to that of 9 (IC50 = 0.093 microM, guinea pig platelet aggregation assay). Compound 9 dose-dependently inhibited ex vivo platelet aggregation in guinea pigs (0.03 and 0.1 mg/kg, i.v.), and long-lasting inhibition of platelet aggregation was observed upon oral administration of 9 (3 mg/kg) to guinea pigs. On the other hand, the activity of 26 disappeared within 1 h after a dose of 1 mg/kg (i.v.). Compound 9 may therefore be useful in the clinical treatment of arterial thrombotic diseases.

Platelets enhance contractility in perfused rat mesenteric arteries: involvement of endothelin-1

We investigated the effects of platelet supernatant on pressor responses to norepinephrine in isolated perfused rat mesenteric arteries. Perfusion of the arteries with platelet supernatant for 2 h markedly enhanced the pressor responses to norepinephrine (10(-6) and 3 x 10(-6) M). This enhancement was significantly inhibited by phosphoramidon (10(-4) M), an endothelin converting enzyme inhibitor. Both BQ788 [N-cis-2,6-dimethylpiperidinocarbonyl-L-gamma-methylleucyl-D -1-methoxycarbonyltryptophanyl-D-norleucine] (10(-6) M), an endothelin ET(B) receptor antagonist, and bosentan (Ro47-0203, 4-tert-butyl-N-[6-(2-hydroxy-ethoxy)-5-(2-methoxy-phenoxy)-2,2-bipyri midin-4-yl]-benzenesulfonamide) (10(-5) M), a nonselective endothelin receptor antagonist, also prevented the potentiation of responses to norepinephrine evoked by platelet supernatant, but FR 139317 ((R)2-[(R)-2-[(S)-2-[[1-(hexahydro-1H-azepinyl)]carbonyl]amino-4-+ ++methylpentanoyl] amino-3-[3-(1-methyl-1H-indoyl)]propionyl]amino-3-(2-pyridyl) propionic acid) (10-6 M), an endothelin ET(A) receptor antagonist, had little effect. Suppressor doses of endothelin-1 (3 x 10(-10) M) or sarafotoxin S6c (S6c) (3 x 10(-10) M) potentiated significantly the norepinephrine-induced vasoconstriction, in the same preparation. Moreover, supernatant-induced enhancement of pressor responses to norepinephrine was markedly suppressed by TGF-beta1 neutralizing antibody. Transforming growth factor-beta1 (TGF-beta1) (40 pM) also significantly enhanced the pressor responses to norepinephrine (10(-6) M) and this enhancement was significantly inhibited by phosphoramidon. These results suggest that platelet-derived TGF-beta1 stimulates the vascular production of endothelin-1 and thereby enhances vasoconstrictor responses to norepinephrine. Platelet-induced enhancement of vasoconstrictor responses to norepinephrine seems to be mainly mediated by endothelin ET(B) receptor, in rat mesenteric arteries.

Differentiation between benign and metastatic cervical lymph nodes with ultrasound

OBJECTIVE

The differentiation between benign and metastatic lymph nodes with ultrasound (US) is based primarily on the evaluation of size, shape, margin and internal echo structure. The aim of this study is to determine whether these parameters are reliable indicators and to correlate internal echo structure and histopathological findings.

MATERIALS AND METHODS

Seventy-one nodes in 21 patients with pathologically proven oral squamous cell carcinoma were examined. The shortest diameter, the short/long diameter ratio (S/L ratio), margins and internal echo structure of the lymph node were evaluated by US. The internal echo structure was divided into six patterns: homogeneous hypoechoic, homogeneous hyperechoic, heterogeneous, eccentric hyperechoic, centric hyperechoic and anechoic pattern. In addition, internal echo structure was correlated with histopathological findings.

RESULTS

In 71.4% of the metastatic nodes, the shortest diameter was more than 10 mm and the S/L ratio was higher than that of benign nodes (average 0.71). Eleven (84.6%) of the 13 lymph nodes with irregular margins were metastatic. Heterogeneous and anechoic patterns were observed in metastatic nodes, whereas homogeneous hypoechoic and eccentric hyperechoic patterns were present in benign nodes. On ultrasonography with the corresponding histopathological findings, echogenic areas in the homogeneous hyperechoic, heterogeneous and centric hyperechoic patterns of metastatic nodes proved to be necrosis or fibrosis. Eccentric hyperechoic areas in benign nodes corresponded to the hilus and surrounding fatty tissue.

CONCLUSIONS

The shortest diameter, S/L ratio, margin and internal echo structure were considered to be critical indicators to differentiate between benign and metastatic nodes. Secondary changes caused by tumour infiltration, necrosis, or fibrosis should be assessed when metastatic lymph nodes are differentiated from benign ones by internal echo structure.

Elevated soluble Fas/APO-1 (CD95) levels in silicosis patients without clinical symptoms of autoimmune diseases or malignant tumours

Soluble Fas (sFas) is produced as translation products of alternative mRNA splicing, and antagonizes the membranous Fas molecule in Fas/Fas ligand interactions. We investigated the serum sFas levels in 64 Japanese silicosis patients with no clinical symptoms of autoimmune diseases or malignant tumours, using ELISA for sFas. The serum sFas levels in the silicosis patients were significantly higher than those in healthy volunteers. Elevated serum sFas levels were also detected in patients with systemic lupus erythematosus but, unexpectedly, no difference was observed in sFas levels between progressive systemic sclerosis patients and healthy volunteers. On the other hand, there was no significant difference in the expression of Fas on peripheral blood lymphocytes between the patients with silicosis and age-matched healthy volunteers. These observations provided the first evidence that serum sFas levels are elevated in silicosis patients without clinical symptoms of autoimmune diseases or malignant tumours. It remains to be clarified whether patients with elevated sFas levels have a tendency to develop autoimmune diseases later, or whether some other distinct factor(s) is necessary to initiate the progression of autoimmune diseases.

Crystallization and preliminary X-ray diffraction studies of expressed Pseudomonas putida catechol 2,3-dioxygenase

Crystals of recombinant Pseudomonas putida catechol 2,3-dioxygenase, metapyrocate-chase, composed of four identical subunits, each with a molecular mass of 35 kDa and one nonheme ferrous iron, have been grown by the vapor diffusion method using sodium citrate as the precipitant. Repeated macroseeding and the addition of ethanol to protein solutions were together effective for obtaining crystals suitable for further crystallographic characterization. The crystals belong to the tetragonal space group P4(2)2(1)2 with unit-cell dimensions of a = b = 266 A, c = 60 A. They diffracted beyond 2.5 A resolution with synchrotron radiation. Assuming that one tetramer (alpha-Fe2+)4 is contained in an asymmetric unit, the crystal volume per unit molecular mass, Vm, is calculated to be 3.8 A3/Da, which corresponds to the solvent content of 67.6%.

[Home oxygen therapy (HOT) in patients with pulmonary tuberculosis sequelae--comparison between patients medically treated and those surgically treated]

In Japan there are about 40,000 patients under home oxygen therapy (HOT), of whom about 30 to 40% are pulmonary tuberculosis sequelae (TBS). These patients can be divided into three groups depending on the treatments they had, Group 1: those who had medical treatments only, Group 2: those who had artificial pneumothorax, and Group 3: those who had thoracoplasties or other surgical treatments. The purpose of this study was to observe the distributions and possible differences in the survival rates among these groups. The study included 1537 patients with TBS under HOT followed at National Hospitals and Sanatoriums nationwide in Japan. In 819 patients the treatments were specified and of those 354 were in Group 1, 29 in Group 2, and 436 in Group 3, so that the proportion of surgically treated patients in PTS was estimated between 28.4% (436/ 1537) to 53.2% (436/819). The ages at the onset of tuberculosis, at the start of HOT and the intervals in between were 36.6, 66.2 and 29.8 in Group 1, and 26.8, 65.5, and 38.1 in Group 3 respectively. Though the ages at the start of HOT were the same, those at the onset of tuberculosis were about ten years younger in Group 3 than in Group 1. Comparing Group 1 and 3, the survival rates after the initiation of HOT (Kaplan-Meier method) was better in Group 2 (surgically treated) than in Group 1 (medically treated). It is speculated that the reason could be a better preservation of the function of the remaining lung in the surgically treated and a higher incidence of obstructive impairments in the medically treated patients.

Sex and age patterns of quantitative ultrasound densitometry of the calcaneus in normal Japanese subjects

: The speed of sound (SOS), broadband ultrasound attenuation (BUA), and the stiffness index (stiffness), which was derived from SOS and BUA, were measured on the calcaneus using the Achilles ultrasound densitometer (Lunar) in normal Japanese woman (n = 473) and men (n = 218). Sex differences and age-related changes in these variables were investigated. In addition, the bone mineral density (BMD) of the lumbar vertebrae measured by dual X-ray absorptiometry (QDR-2000, Hologic) was compared with SOS, BUA, and stiffness. There were some decreases of ultrasound variables in both young adult men and women. BMD values were similar in young adults of both sexes. BMD was relatively stable in women from 20 to 49 years, then decreased at about 1.5%/year. Ultrasound variables were higher in males than females at all ages, and they decreased from age 20 onward in both sexes with an annual loss of about 0.6%. Age-related changes in SOS, BUA, and stiffness were different from those in BMD in normal Japanese subjects. The correlations between BMD and SOS and BUA and stiffness were higher in women (r = 0.51-0.64) than in men (r = 0. 43-0.49).

Morphological changes of autoclaved autogenic bone implantation and autoclaved autogenic bone supplemented with allogenic demineralized bone matrix in rat parietal bone

The healing process of resected, autoclaved (121 degrees C, 20 minutes) and re-implanted bone in the rat parietal bone was compared with that of autoclaved bone that was supplemented with allogenic bone matrix (AAA-bone), using a scanning electron microscope and a light microscope. In the implant without AAA-bone, bone union and replacement of the autoclaved bone was seen at 2 weeks after implantation. There was no evidence of any inflammatory reaction around the autoclaved bone. The implant was gradually replaced by the new bone. In the implant with AAA-bone, the new bone formation around the implanted bone was more abundant than that of the implant without AAA-bone. An inflammatory reaction was also observed after 1 week. The replacement of the implant with AAA-bone was inferior to the nonsupplemented group. The reason for the poor replacement was the disturbance of the blood supply in the implant by abundant new bone formation. In these results, the autoclaved bone re-implantation was an excellent bone substitute with osteoconductive ability and biocompatibility. The implantation with AAA-bone was good for the new bone formation, but the position and the technique of supplement with AAA-bone have to be more deeply investigated.

Antithrombotic effects of TAK-029, a novel GPIIb/IIIa antagonist, in guinea pigs: comparative studies with ticlopidine, clopidogrel, aspirin, prostaglandin E1 and argatroban

The antithrombotic and bleeding time (BT)-prolonging effects of TAK-029, a novel glycoprotein IIb/IIIa antagonist, were characterized and compared with those of conventional antithrombotic agents in guinea pigs. TAK-029 potently inhibited the binding of fibrinogen and von Willebrand factor to purified human GPIIb/IIIa with IC50 values of 0.67 +/- 0.03 and 0.33 +/- 0.04 nM; it also inhibited human platelet aggregation induced by various aggregating agents with IC50 values of 29 to 38 nM. The in vitro antiplatelet effect of TAK-029 was potent in humans, guinea pigs and monkeys. When TAK-029 was given p.o. to guinea pigs, severe prolonging of BT (>1800 sec) was not observed with plasma concentrations of TAK-029 that inhibited ex vivo platelet aggregation by < 100%. The p.o. administration of TAK-029, ticlopidine and clopidogrel prolonged BT to the same extent, in parallel with their inhibition of ex vivo platelet aggregation. TAK-029 inhibited ex vivo platelet adhesion and thrombus formation in an arteriovenous shunt model more strongly than ticlopidine, clopidogrel and aspirin at doses causing similar prolongations of BT. In a balloon catheter-induced carotid thrombosis model, i.v. administration of TAK-029 significantly inhibited thrombus formation without prolonging BT. At doses that caused an incomplete antithrombotic effect, PGE1-alpha-cyclodextrin and argatroban produced hypotension and prolongation of BT, respectively. TAK-029 may be effective in patients suffering from arterial thrombotic diseases, which are refractory to these conventional antithrombotic agents.

Characterization of distribution of T lymphocyte subsets and activated T lymphocytes infiltrating into sarcoid lesions

We studied the relationship between various T lymphocyte functions and granuloma formation in 5 lung tissue and 4 lymph node tissue samples from patients with sarcoidosis by immunohistological methods. In the lesion of sarcoidosis, T cells were positive for alpha beta TCR, but gamma delta TCR-positive T cells were rarely observed. The results of analysis of functional subsets showed that T cells in the internal area of granuloma were predominantly helper/inducer subset (CD4+CD45RA-). On the other hand, cytotoxic T cells (CD8+CD45RA-CD11b-) were present in abundance in the outer boundaries of granuloma. In addition, suppressor-inducer T cells (CD4+CD45RA+) were present in the surrounding areas. However, T cells of various subsets were present sporadically outside the granulomas. We also studied the distribution of T cells expressing activation-related antigens. The results showed that T lymphocytes in the internal area of granulomas more frequently had these antigens than did T lymphocytes in the external area. These findings suggested that T cells infiltrating into the sarcoidosis lesion demonstrated a layer-like distribution based on functional subsets. These findings also confirm that activated T cells were more abundantly distributed in the internal area of sarcoid granuloma than in the external area.

Antihypertensive effect of sesamin. II. Protection against two-kidney, one-clip renal hypertension and cardiovascular hypertrophy

We investigated the antihypertensive effect of sesamin, a lignan from sesame oil, using two-kidney, one-clip (2K,1C) renal hypertensive rats. After clipping the left renal artery, animals were assigned to either a normal diet group (control group) or a sesamin-containing (1% (w/w)) diet group (sesamin group). The sham-operated rats (sham group) were fed a normal diet and tap water. The systolic blood pressure of the control group increased progressively in comparison with the sham group. This 2K,1C-induced hypertension was markedly reduced by feeding the sesamin-containing diet. The systolic blood pressure after 4 weeks was 123.60 +/- 4.01 mmHg in the sham group, 187.43 +/- 5.69 mmHg in the control group and 145.57 +/- 6.78 mmHg in the sesamin group, respectively. There were significant increases in left ventricle plus septum weight-body weight ratio in the control group compared with the sham group. This rise was also significantly reduced in the sesamin group. When the thoracic aorta was histochemically evaluated, the wall thickness and wall-to-lumen ratio in the control group were significantly increased, compared with the sham group, indicating that vascular hypertrophy had occurred in the control group. The sesamin diet tended to ameliorate this vascular hypertrophy, although its effect was not statistically significant. These findings suggest that sesamin is useful as prophylactic treatment to combat the development of renal hypertension and cardiac hypertrophy.

Scanning electron and light microscopic observations on the healing process after sintered bone implantation in rats

The healing process after implantation of sintered bone in the rat parietal bone was compared with that of synthetic hydroxyapatite using both scanning electron and light microscopy. The results showed that the differences between the sintered natural bone and the synthetic hydroxyapatite implantations were in the states of bone union and the bioresorbability of the implanted materials, even though both materials consist of the same hydroxyapatite. In the sintered bone implantation, the newly formed bone invaded into the material at 1 to 2 weeks after implantation. The sintered bone surface on the dura mater side was completely covered by the new bone at 5 weeks. It is noteworthy that bone resorbing areas characterized by Howship's lacunae were observed on the sintered bone surface at 2 weeks and the material was replaced by new bone. Light microscopy, which revealed the invasion and the development of the new bone into the sintered bone, supported the scanning electron microscopic observations. In the synthetic hydroxyapatite, the new bone adhered closely to the material just like the sintered bone implantation. The new bone did not invade into the synthetic hydroxyapatite. There was no evidence of the resorption of the hydroxyapatite. This shows that the natural and the biological structures of the sintered bone offer an advantageous environment to fluid circulation and ingrowth after implantation.

Antihypertensive effect of sesamin. I. Protection against deoxycorticosterone acetate-salt-induced hypertension and cardiovascular hypertrophy

We investigated the antihypertensive effect of sesamin, a lignan from sesame oil, using deoxycorticosterone acetate (DOCA)-salt hypertensive rats. The animals were unilaterally nephrectomized, and then separated into a sham-operated group (sham group) and a DOCA-salt-treated group. The latter was further separated into a normal diet group (control group) and a sesamin-containing diet group (sesamin group). The systolic blood pressure of control group progressively increased in comparison with that of sham group. This DOCA-salt-induced hypertension was markedly suppressed by feeding a sesamin-containing diet. Systolic blood pressure after 5 weeks was 130.6 +/- 1.9 mmHg in the sham group, 198.1 +/- 7.3 mmHg in the control group and 152.5 +/- 8.4 mmHg in the sesamin group, respectively. The treatment with DOCA and salt for 5 weeks significantly increased the weight of the left ventricle plus the septum. However, this increase was significantly suppressed in the sesamin group. When the degree of vascular hypertrophy of the aorta and superior mesenteric artery was histochemically evaluated, there were significant increases in wall thickness, wall area and the wall-to-lumen ratio in the control group, compared with the sham. Sesamin feeding ameliorated the development of DOCA-salt-induced vascular hypertrophy in both the aorta and mesenteric artery. These findings strongly suggest that sesamin is useful as a prophylactic treatment in the development of hypertension and cardiovascular hypertrophy.

Role of endothelin-1 and the ETA receptor in the maintenance of deoxycorticosterone acetate-salt-induced hypertension

1. To search for a possible role for endothelin-1 (ET-1) in deoxycorticosterone acetate (DOCA)-salt-induced hypertension, we examined changes in concentration of ET-1 in vascular and renal tissue in DOCA-salt hypertensive rats and evaluated the antihypertensive effect of the ETA receptor antagonist, FR139317. 2. There was an increase in aortic immunoreactive-ET (IR-ET) concentrations in association with hypertension-induced treatment. There were no significant changes in ET-1 levels in the kidney with DOCA-salt treatment. 3. In DOCA-salt hypertensive rats, a significant correlation (r = 0.83, P < 0.01) was found between aortic IR-ET concentrations and systolic blood pressure. 4. High-performance liquid chromatography analysis of the aortic extract from DOCA-salt rats revealed one major component corresponding to the elution position of synthetic ET-1. 5. The intravenous bolus injection of FR139317 (10 mg kg-1) produced a slight decrease in blood pressure in the control rats and in the DOCA-salt hypertensive rat, FR139317 had a more pronounced hypotensive effect. 6. We propose that ET-1 production in vascular tissues is increased in DOCA-salt hypertensive rats. In addition, our study indicates the pathophysiological importance of increased endogenous ET-1 in the maintenance of DOCA-salt-induced hypertension, through interaction of the peptide with ETA receptors.

Identification of IL-1 inhibitory activity as IL-1 receptor antagonist (IL-1ra) in vitro and kinetics of IL-1ra and IL-1 beta in experimental rabbit lung granuloma

This study investigated whether interleukin-1 (IL-1) inhibitory activity in LPS-stimulated culture supernatants of alveolar macrophages and epithelioid cells obtained from rabbit lung granulomas induced by complete Freund's adjuvant (CFA) was identical to IL-1 receptor antagonist (IL-1ra) and examined the changes of IL-1ra and IL-1 beta levels in lung tissue during the natural course of granulomatous inflammation. In the thymocyte proliferation assay, prostaglandin E2 (PGE2)-free culture supernatants from each cell population revealed a bell-shaped IL-1 titration curve with IL-1 activity suppressed at dilutions of 1:1 to 1:2, and gel chromatography of serum-free culture supernatants showed an IL-1 inhibitory peak at 21-25 kD. Suppression of IL-1 activity in the supernatants at lower dilutions and the gel-purified IL-1 inhibitory activity both almost disappeared after IL-1ra depletion with an anti-rabbit IL-1ra immunoaffinity column, indicating that IL-1ra was responsible for this in vitro IL-1 inhibitory activity. Pulmonary tissue levels of IL-1 beta pecked at 24 h (52.0 +/- 9.5 pg/mg) after CFA injection, whereas IL-1ra levels peaked at 4 weeks (23.1 +/- 4.0 ng/mg) when granuloma development was maximal, and the molar excess of IL-1ra to IL-1 beta peaked from 4 weeks onward at over 800-fold. These observations suggest that IL-1ra may be effective for IL-1 regulation, especially in the later stage of granulomatous responses. Immunohistochemical studies demonstrated that the cellular source of IL-1ra within the pulmonary granulomas was mainly epithelioid cells.