Suppressive effect of N-(benzyloxycarbonyl)-L-phenylalanyl-L-tyrosinal on bone resorption in vitro and in vivo

The suppressive effect of N-(benzyloxycarbonyl)-L-phenylalanyl-L-tyrosinal on bone resorption was examined in vitro and in vivo. This synthetic peptidyl aldehyde was found to be a potent and selective cathepsin L inhibitor in our screening for cysteine protease inhibitors. In the pit formation assay with unfractionated rat bone cells, 1.5 nM of this compound markedly inhibited parathyroid hormone-stimulated osteoclastic bone resorption. In addition, intraperitoneal administration of this peptidyl aldehyde (2.5-10 mg/kg) for 4 weeks suppressed bone weight loss dose dependently in the ovariectomized mouse, experimental model of osteoporosis. Hydroxyproline measurement of the decalcified femurs from these ovariectomized mice suggested that this compound acts as a bone resorption suppressor through the inhibition of collagen degradation.

Spheroid cultures of human hepatoblastoma cells (HuH-6 line) and their application for cytotoxicity assay of alcohols

Spheroid cultures of human hepatoblastoma cells (HuH-6 line) were established by rotating 3 x 10(6) cells/3 ml culture medium in 25-ml Erlenmeyer flasks on a gyratory shaker. The size of the spheroids rapidly increased until 4 days of culture, and thereafter their size gradually increased until 8 days of culture. A considerable amount of lactate dehydrogenase (LDH) was detected in the culture medium at 24h after seeding because of cell damage by subculturing, but thereafter the amount released was small, indicating that the spheroids were in healthy condition. Albumin production, one of the differentiated functions of hepatocytes, was higher in spheroid cultures than in monolayer cultures. Using this spheroid culture model, the cytotoxic effects of alcohols on HuH-6 cells were studied by measuring the activity of LDH released in the medium from damaged cells. The results indicate that the increasing order of toxicity of the alcohols was as follows: methanol < ethanol < propanol.

Apoptosis and proliferation of human hepatocellular carcinoma

To investigate the contribution of apoptosis, a major mechanism of cell death, in the growth of hepatocellular carcinoma, we analyzed both apoptosis and cell proliferation in human hepatocellular carcinoma. We used the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling method and proliferative cell nuclear antigen staining, respectively. Among 21 hepatocellular carcinoma specimens examined, four were well, ten were moderately, and seven were poorly differentiated hepatocellular carcinoma. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling-positive cells in hepatocellular carcinoma were scattered individually or were sometimes clustered in the tumors. The terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling indices were 0.35 +/- 0.09, 0.81 +/- 0.29, and 1.9 +/- 0.94 in well, moderately, and poorly differentiated hepatocellular carcinoma, respectively. The proliferative cell nuclear antigen labeling indices were 6.6 +/- 0.9, 13.1 +/- 3.5, and 26.7 +/- 6.3 in hepatocellular carcinoma in the same respective order of differentiation. The differences in both terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling indices and proliferative cell nuclear antigen labeling indices (p < 0.05) were significant between well, moderately and poorly differentiated hepatocellular carcinoma. There was a positive correlation between the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling and proliferative cell nuclear antigen labeling indices in hepatocellular carcinoma (r = 0.84, p < 0.001). This study showed that the proliferation rate and the incidence of apoptosis increased as the differentiation grade of hepatocellular carcinoma was lowered, suggesting a rapid turnover of cancer cells in the lower differentiation grades. Apoptosis may thus play an important role in the growth of hepatocellular carcinoma.

Effect of clot removal on cerebrovascular contraction after subarachnoid hemorrhage in the monkey: pharmacological study

Clot removal at early surgery has been reported to be clinically effective for the prevention of cerebral vasospasm following subarachnoid hemorrhage (SAH) due to rupture of an intracranial aneurysm. We examined the most efficacious timing of mechanical clot removal on pharmacological responses in a monkey SAH model. Cynomolgus monkeys (Macaca fascicularis) were randomized into five groups: sham-operated, clot removal in which the clot was removed 48, 72, or 96 h after SAH, and clot groups. An autologous blood clot was placed around the bilateral major cerebral arteries after craniectomy to mimic the hemorrhage. Seven days after the SAH, proximal and successively distal parts of the middle cerebral arteries were cut into rings for isometric tension measurement. The contractile responses to potassium chloride, 5-hydroxytryptamine, norepinephrine, adenosine triphosphate, prostaglandin F20, and hemoglobin were greater in the proximal parts than in the distal parts in each group. Compared with the sham-operated group, the responses of the clot-removal and clot groups to the drugs were progressively attenuated. The maximum responses to 5-hydroxytryptamine in the proximal parts and to adenosine triphosphate in the distal parts started to decrease, significantly, in the clot-removal group 48 h after SAH, while most of the responses to the other agonists began to decrease in the clot-removal groups later than 72 h after SAH. These results suggest that the attenuation of cerebrovascular contractile responses 7 days after SAH is pharmacologically inevitable, even if the clot is removed as early as 48 h after the SAH. Clot removal may thus be recommended within 48h after SAH to ameliorate the severity of cerebral vasospasm following SAH.

Elevated plasma superoxide dismutase activity in patients with systemic sclerosis

Injury to vessel walls, especially microvascular damage due to free radicals, has been a focus of interest concerning the pathogenesis of systemic sclerosis. Excess reactive oxygen species may induce antioxidant defenses. We therefore measured plasma superoxide dismutase (SOD) activity in patients with systemic sclerosis and found average SOD activity of plasma in 16 patients with systemic sclerosis (5.00 +/- 3.10 U/ml) to be significantly (P < 0.001) higher than those in 89 healthy volunteers (1.56 +/- 0.234 U/ml). Patients with Raynaud's phenomenon and/or skin sclerosis had particularly high SOD activity. These findings suggest that plasma SOD activity may serve as a useful parameter for assessment of sclerotic progression and the presence of Raynaud's phenomenon.

Cytochrome P450s of isolated rat hepatocytes in spheroid and monolayer cultures

The maintenance of cytochrome P450s (P450s) and NADPH-cytochrome P450 reductase (P450 reductase) in the monolayer and spheroid cultures of hepatocytes from male rats was examined. The content of total P450 in monolayer culture decreased to almost none after 144 hr, whereas the level in spheroid culture remained within 6-13% of initial values during an incubation period of 144-192 hr. P450 2C11, a major P450 in male rat, in monolayer cells rapidly decreased in 144 hr, while the level in spheroid cells after 144 hr and 192 hr maintained 25% and 15%, respectively, of initial level. On the other hand, P450 2A1 and P450 2E1 in both monolayer and spheroid cells rapidly decreased. P450 reductase in both cells showed a gradual decline reaching a level of 43-44% of the initial level at 96 hr, and remained within 16-17% of the initial value during an incubation period of 192 hr. These results indicate that P450 2C11 in spheroid cells maintained more stable than in the monolayer cells, and that P450 reductase in both cultures declined only moderately, compared with P450s.

A classical strain of Vibrio cholerae with diminished ability to process the proteolytically sensitive site in the A subunit of cholera toxin

Vibrio cholerae O1, No. 31, a strain isolated from a patient with mild diarrhea, produced mainly the unnicked cholera toxin. The amount of toxin that had accumulated in the cells was approximately 200 times lower than that secreted into the culture medium. When the unnicked toxin was purified by three successive column chromatographies and then extracted from the polyacrylamide gel, the unnicked toxin showed two bands corresponding to the A and B subunits by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the A1 fragment was detected by trypsinization. Biological and enzymatic activities of the purified toxin with trypsinization were identical to those of cholera toxin from V. cholerae 569B as seen in the rabbit skin permeability test and the NAD:agmatine ADP-ribosyltransferase assay. DNA sequences of the A and B subunits were identical to those of the A- and B-subunit genes from the El Tor 2125 and classical 0395 strains, respectively. These data suggest that the wild V. cholerae strain, No. 31, produces a toxin identical to toxins previously reported in the literature and secretes it without accumulation in the cell, as is the case with other strains. However, strain No. 31's ability to nick the toxin is diminished compared with such abilities of other strains.

Tenascin expression in endomyocardial biopsy specimens in patients with dilated cardiomyopathy: distribution along margin of fibrotic lesions

OBJECTIVE

To examine the hypothesis that tenascin, an extracellular matrix glycoprotein, contributes to fibrotic changes in dilated cardiomyopathy.

METHODS

The localisation of tenascin in biopsy specimens of the hearts obtained from eight patients with dilated cardiomyopathy was examined using staining by the avidin-biotin-peroxidase complex method.

RESULTS

(1) Perimysium and endomysium. Although positive staining for tenascin was observed in the enlarged perimysium and endomysium in all patients, moderately intense staining was characteristically observed near the replacement fibrotic lesions. In the narrow perimysium and endomysium of the myocardium not containing replacement fibrotic lesions, tenascin was not present, as in the control specimens. (2) Replacement fibrotic lesions. Non-homogeneous positive staining for tenascin was detected in all replacement fibrotic lesions examined. Intense tenascin deposition was observed in the peripheral portion of the replacement fibrotic lesions. The tenascin staining observed in the small replacement fibrotic lesions was more intense than that in the large lesions.

CONCLUSIONS

Tenascin contributes to the development of the fibrotic changes seen in the dilated cardiomyopathic heart. Its characteristic location, specifically the distribution along the margin of the fibrosis, suggests that fibrotic change is a continuous process in hearts with dilated cardiomyopathy.

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

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

Engineering specificity for folate into dihydrofolate reductase from Escherichia coli

Despite several similarities in structure and kinetic behavior, the bacterial and vertebrate forms of the enzyme dihydrofolate reductase (DHFR) exhibit differential specificity for folate. In particular, avian DHFR is 400 times more specific for folate than the Escherichia coli reductase. We proposed to enhance the specificity of the E. coli reductase for folate by incorporating discrete elements of vertebrate secondary structure. Two vertebrate loop mutants, VLI and VLII containing 3-7 additional amino acid insertions, were constructed and characterized by using steady-state kinetics, spectrofluorimetric determination of ligand equilibrium dissociation constants, and circular dichroism spectroscopy. Remarkably, the VLI and VLII mutants are kinetically similar to wild-type E. coli reductase when dihydrofolate is the substrate, although VLII exhibits prolonged kinetic hysteresis. Moreover, the VLI dihydrofolate reductase is the first mutant form of E. coli DHFR to display enhanced specificity for folate [(kcat/Km)mutant/(kcat/Km)wt = 13]. A glycine-alanine loop (GAL) mutant was also constructed to test the design principles for the VLI mutant. In this mutant of the VLI reductase, all of the residues from positions 50 to 60, except the strictly conserved amino acids Leu-57 and Arg-60, were converted to either glycine or alanine. A detailed kinetic comparison of the GAL and wild-type reductases revealed that the mutations weaken the binding by both cofactor and substrate by up to 20-fold, but under saturating conditions the enzyme exhibits a kcat value nearly identical to that of the wild type. The rate of hydride transfer is reduced by a factor of 30, with a compensating increase in the dissociation rate for tetrahydrofolate. Although key stabilizing interactions have been sacrificed (it shows no activity toward folate), the maintenance of the correct register between key residues preserves the activity of the enzyme toward its natural substrate. Collectively, neither specific proximal point site mutations nor larger, more distal secondary structural substitutions are sufficient to confer a specificity for folate reduction that matches that observed with the avian enzyme. This is consistent with the hypothesis that the entire protein structure must contribute extensively to the enzyme's specificity.

Persistence of hepatitis C virus RNA in established human hepatocellular carcinoma cell lines

The persistence of the viral RNA of hepatitis C virus (HCV) was examined in 13 hepatocellular carcinoma (HCC) and two hepatoblastoma cell lines by reverse transcription followed by the polymerase chain reaction (RT-PCR). HCV RNA was detected in three HCC lines (JHH-1, JHH-4, and JHH-6) and negative-strand viral RNA was found in JHH-4, indicating that there is a putative replicative intermediate of HCV in JHH-4 cells. To rule out the possibility of contamination, the partial nucleotide sequences of HCV-specific PCR products of these three cell lines were determined. The clone from JHH-1 belonged to genotype 1 (1a or 1b), and the clones from JHH-4 and JHH-6 belonged to genotype 2b, but their sequences differed from each other. These cell lines may be useful for studies related to HCV.

Detection of hepatitis C virus core protein in the glomeruli of patients with membranous glomerulonephritis

Two Japanese patients suffered from membranous glomerulonephritis associated with hepatitis C virus (HCV) infection. Renal histologic changes were characterized by granular deposits of IgG and C3 along the capillary wall and numerous subepithelial deposits in glomeruli. Hypocomplementemia was present in one patient, but both cryoglobulins and rheumatoid factors were absent. HCV RNA was detected in both their sera by RT-PCR, both free and in the form of circulating immune complexes. The HCV core protein was found in the glomeruli from both patients by indirect immunofluorescence. These results suggest that in some patients chronic HCV infection causes membranous glomerulonephritis through immune complex deposition involving HCV proteins.

Sequential changes in laminin and type IV collagen in the infarct zone--immunohistochemical study in rat myocardial infarction

BACKGROUND

The healing process, which affects ventricular remodeling, is an important factor in the prognosis of myocardial infarction. We hypothesized that laminin and type IV collagen contribute to extracellular matrix assembly in healing after myocardial infarction. We examined sequential changes in these two components after experimental myocardial infarction in rats.

MATERIALS AND METHODS

Hearts were excised from 1 day to 10 weeks after permanent left coronary ligation in rats. Immunohistochemical staining with a polyclonal antibody to laminin and type IV collagen was performed by the avidin-biotin-peroxidase method.

RESULTS

Laminin: On day 3, laminin initially appeared in a wavy fashion in the granulation tissue of the infarct peripheral zone and was not restricted to the cell membrane; the staining distribution in the peripheral zone then gradually increased, reaching a maximum on days 7-11. The distribution progressed from the peripheral zone to the outer lesion of the central zone of the infarct for 1-2 days, and reached the center point after 2 weeks. The extent of the staining distribution gradually decreased after reaching this maximum, but the staining did not completely disappear. Type IV Collagen: Changes in type IV collagen were essentially the same as those in laminin. A wavy staining pattern of type IV collagen appeared in the infarct peripheral zone from day 3, reached its maximum extent on days 7-11, and decreased gradually thereafter. The distribution progressed from the peripheral zone to the outer lesion of the central zone for 1-2 days, reaching the center point after 2 weeks.

CONCLUSIONS

Laminin and type IV collagen contribute to extracellular matrix formation in the infarct zone relatively early after myocardial infarction.

Concanamycin B, a vacuolar H(+)-ATPase specific inhibitor suppresses bone resorption in vitro

Effects of concanamycin B, a specific inhibitor of the vacuolar type H(+)-ATPase (V-ATPase), on the stimulation of bone resorption induced by parathyroid hormone (PTH) were examined in vitro. Concanamycin B was found to inhibit PTH-stimulated osteoclastic pit formation and to suppress the acidification of vacuolar organelles by V-ATPase in the osteoclasts. PTH-stimulated 45Ca release from prelabelled chick embryonic calvariae was also inhibited by concanamycin B in a dose-dependent manner. These results suggest that osteoclastic acidification of lacunae by V-ATPase plays an essential role in mineral dissolution and degradation of the organic matrix during bone resorption.

Immunohistochemical study of proteoglycans in D-galactosamine-induced acute liver injury in rats

In this study, we carried out an immunohistochemical investigation of time-dependent alterations in the distribution of proteoglycans, and the proliferation profiles of hepatocytes and fat-storing cells (FSCs) in the livers of rats intoxicated with D-galactosamine (GalN). The proliferative cells were analyzed by proliferative cell nuclear antigen (PCNA) staining. In untreated rats, heparan sulfate, dermatan sulfate, and chondroitin/chondroitin sulfate were detected within the portal spaces and the central veins, and, with the exception of chondroitin, also within the reticular fibers. After administration of GalN, the number of PCNA-positive cells (FSCs and hepatocytes) and FSCs increased, reaching maximal on the 2nd and 3rd days, respectively. Heparan sulfate showed complicated changes. Dermatan sulfate decreased in portal spaces from the 2nd to the 3rd day, and in reticular fibers from 12 h to the 6th day. Chondroitin/chondroitin sulfate staining was observed from 2 h to the 6th day in the sinusoidal endothelia, which suggests that the sinusoidal endothelia may produce chondroitin/chondroitin sulfate transiently during liver damage as part of the mechanism of regeneration. Heparan sulfate and chondroitin/chondroitin sulfate were detected in necrotic regions, but dermatan sulfate was not. These observations suggest that heparan sulfate and chondroitin/chondroitin sulfate are involved in cell proliferation or morphogenesis and that the dermatan sulfate plays a role in the differentiation or functional maintenance of cells in liver regeneration.

[HLA antigens in patients with testicular germ cell tumors]

The role of HLA antigens in the etiology of testicular germ cell tumor has been suggested previously. Several attempts have been made to establish associations of HLA antigens in patients with testicular cancers, but have yielded inconsistent results. We studied the frequencies of HLA antigens by serological typing and DNA typing and examined the association between testicular germ cell tumors and HLA antigens. The serological expression of HLA-A, -B, -C, -DR and -DQ antigens was analyzed in 23 patients with germ cell cancers of the testis. The findings indicated a trend towards an increase in the antigen DQ4 (p < 0.05). The 13 patients were typed for HLA DRB1 and DQB1 allele by PCR-RFLP analysis. The findings revealed an increased frequency of DRB1 0405 (p < 0.01) and DQB1 0401 (p < 0.01).

Cyclooxygenase induction is essential for NGF synthesis enhancement by NGF inducers in L-M cells

Nerve growth factor (NGF) inducers, for example, 4-methylcatechol, pyrroloquinoline quinone, kansuinin A, and ingenol triacetate, stimulate NGF synthesis in L-M cells, but the mechanism of NGF induction by NGF inducers is not known. Using the four different types of previously described NGF inducers, we proved induction of cyclooxygenase activity by NGF inducers and detected prostaglandins D2 and E2 as metabolites of arachidonic acid. From the observation that the induction of NGF by each NGF inducers was inhibited by cyclooxygenase inhibitors or dexamethasone, cyclooxygenase activation is supposed to be an essential process for NGF induction.

Salivary EGF regulates eosinophil-derived TGF-alpha expression in hamster oral wounds

Using hamster as an oral wound healing model, we examined eosinophils and their expression of transforming growth factor-alpha (TGF-alpha) and transforming growth factor-beta 1 (TGF-beta 1). Oral wounds healed approximately two times faster than their cutaneous counterparts. Eosinophils infiltrated prominently into oral wounds; however, unlike the dual expression of TGF-alpha and TGF-beta 1 in skin wounds, oral wound-associated eosinophils expressed TGF-beta 1, but not TGF-alpha. Because saliva is present in oral environments and contains epidermal growth factor (EGF) and TGF-alpha, sialoadenectomy was performed in this model to determine whether the lack of TGF-alpha expression by eosinophils in oral wounds is due to the presence of salivary EGF and/or TGF-alpha. We found that eosinophils in sialoadenectomized hamsters did express TGF-alpha during oral wound healing but that such expression was suppressed when EGF was added to their drinking water. Taken together, our findings suggest that eosinophil-derived TGF-alpha and salivary TGF-alpha/ EGF may have complementary roles in contributing to TGF-alpha in oral wound healing.

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

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

[Diagnostic value of high N-isopropyl-p-[123I] iodoamphetamine (IMP) uptake in brain tumors]

The diagnostic value of high N-isopropyl-p-[123I] iodoamphetamine (123I-IMP) uptake in histologically proven intracranial tumors was evaluated in 54 patients with both early (15-35 min after injection) and delayed (4 hours) SPECT before treatment. Higher uptake in the tumor compared with normal cerebral cortex was observed in early scans in all of the five patients with primary intracranial malignant lymphoma, in two of 16 meningiomas, two of seven astrocytomas, one of three pituitary adenomas, and one central neurocytoma. Among these 11 cases all the malignant lymphomas showed persistent high uptake in delayed scans, whereas other tumors showed decreased uptake in delayed scans. This persistent high 123I-IMP uptake was characteristic of primary intracranial malignant lymphomas and was useful in the diagnosis of intracranial malignant lymphoma.

Multi-point impedance control for redundant manipulators

This paper proposes an impedance control method called the multi-point impedance control (MPIC) for redundant manipulators. The method can not only control end-effector impedance, but also regulate impedances of several points on the links of the manipulator, which are called virtual end-point impedances, utilizing arm redundancy. Two approaches for realizing the MPIC are presented. In the first approach, controlling the end-effector impedance and the virtual end-point impedances are considered as the tasks with the same level, and the joint control law developed in this approach can realize the closest impedances of the multiple points, including the end-effector and the virtual end-points to the desired ones in the least squared sense. On the other hand, in the second approach, controlling the end-effector impedance is considered the most important task, and regulating the impedances of the virtual end-points is considered as a sub-task. Under the second approach, the desired end-effector impedance can be always realized since the joint control torque for the regulation of the virtual end-point impedances is designed in such a way that it has no effect on the end-effector motion of the manipulator. Simulation experiments are performed to confirm the validity and to show the advantages of the proposed method.