Blockade of AT1 receptors protects the blood-brain barrier and improves cognition in Dahl salt-sensitive hypertensive rats

BACKGROUND

The present study tested the hypothesis that inappropriate activation of the brain renin-angiotensin system (RAS) contributes to the pathogenesis of blood-brain barrier (BBB) disruption and cognitive impairment during development of salt-dependent hypertension. Effects of an angiotensin II (AngII) type-1 receptor blocker (ARB), at a dose that did not reduce blood pressure, were also examined.

METHODS

Dahl salt-sensitive (DSS) rats at 6 weeks of age were assigned to three groups: low-salt diet (DSS/L; 0.3% NaCl), high-salt diet (DSS/H; 8% NaCl), and high-salt diet treated with ARB, olmesartan at 1 mg/kg.

RESULTS

DSS/H rats exhibited hypertension, leakage from brain microvessels in the hippocampus, and impaired cognitive functions, which were associated with increased brain AngII levels, as well as decreased mRNA levels of tight junctions (TJs) and collagen-IV in the hippocampus. In DSS/H rats, olmesartan treatment, at a dose that did not alter blood pressure, restored the cognitive decline, and ameliorated leakage from brain microvessels. Olmesartan also decreased brain AngII levels and restored mRNA expression of TJs and collagen-IV in DSS/H rats.

CONCLUSIONS

These results suggest that during development of salt-dependent hypertension, activation of the brain RAS contributes to BBB disruption and cognitive impairment. Treatment with an ARB could elicit neuroprotective effects in cognitive disorders by preventing BBB permeability, which is independent of blood pressure changes.

Nifedipine, a calcium-channel blocker, attenuated glucose intolerance and white adipose tissue dysfunction in type 2 diabetic KK-A(y) mice

BACKGROUND

To explore the metabolic actions of nifedipine on diabetes, we examined glucose intolerance and white adipose tissue changes in type 2 diabetic KK-A(y) mice.

METHODS

Male KK-A(y) mice were treated with nifedipine (1.5 mg/kg/day in lab chow) for 5 weeks, which did not affect blood pressure or feeding of KK-A(y) mice.

RESULTS

After treatment with nifedipine, body weight tended to decrease and the weight of white adipose tissue was reduced. Without food restriction, nifedipine decreased plasma insulin level, while plasma glucose level tended to decrease. In oral glucose tolerance test, nifedipine suppressed the increase in glucose level after a glucose load without affecting plasma insulin concentration. Nifedipine also improved the result of insulin tolerance test. In white adipose tissue, nifedipine increased adipocyte number and the expression of peroxisome proliferator-activated receptor-γ (PPARγ) and adipocyte fatty acid-binding protein related to adipocyte differentiation. In addition, expression of adiponectin, insulin receptor, insulin receptor substrate-1, and glucose transporter type-4 was also increased by nifedipine. Nifedipine also increased the expression of NO synthase in white adipose tissue. Nifedipine did not affect expression of angiotensin II type 1 (AT₁) and type 2 (AT₂) receptors in white adipose tissue. Such changes in white adipose tissue were apparent in retroperitoneal adipose tissue. Nifedipine did not change the expression of angiotensin receptors, renin receptor, and angiotensinogen in white adipose tissue. Moreover, nifedipine attenuated nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity and increased superoxide dismutase (SOD) activity in white adipose tissue.

CONCLUSION

These results suggest that nifedipine can enhance insulin sensitivity and reduce white adipose tissue, possibly related to stimulation of adipocyte differentiation.

Vasodilator therapy with hydralazine induces angiotensin AT receptor-mediated cardiomyocyte growth in mice lacking guanylyl cyclase-A

BACKGROUND AND PURPOSE

Recent clinical guidelines advocate the use of the isosorbide dinitrate/hydralazine combination in treatment for heart failure. However, clinical and laboratory evidence suggest that some vasodilators may induce cardiac hypertrophy under uncertain conditions. This study investigated the effects and underlying mechanism of action of the vasodilator hydralazine on cardiac growth.

EXPERIMENTAL APPROACH

Wild-type mice and animals deficient in guanylyl cyclase-A (GCA) and/or angiotensin receptors (AT(1) and AT(2) subtypes) were treated with hydralazine ( approximately 24 mg.kg(-1).day(-1) in drinking water) for 5 weeks. Cardiac mass and/or cardiomyocyte cross-sectional area, fibrosis (van Giessen-staining) and cardiac gene expression (real-time RT-PCR) were measured.

KEY RESULTS

Hydralazine lowered blood pressure in mice of all genotypes. However, this treatment increased the heart and left ventricular to body weight ratios, as well as cardiomyocyte cross-sectional area, and cardiac expression of atrial natriuretic peptide mRNA in mice lacking GCA. Hydralazine did not affect cardiac hypertrophy in wild-type mice and mice lacking either AT(1) or AT(2) receptors alone. However, the pro-hypertrophic effect of hydralazine was prevented in mice lacking both GCA and AT(2), but not GCA and AT(1) receptors. However, hydralazine did decrease cardiac collagen deposition and collagen I mRNA (signs of cardiac fibrosis) in mice that were deficient in GCA, or both GCA and AT(2) receptors.

CONCLUSIONS AND IMPLICATIONS

The vasodilator hydralazine induced AT(2) receptor-mediated cardiomyocyte growth under conditions of GCA deficiency. However, attenuation of cardiac fibrosis by hydralazine could be beneficial in the management of cardiac diseases.

AT2 receptor deficiency attenuates adipocyte differentiation and decreases adipocyte number in atherosclerotic mice

BACKGROUND

Previous reports indicated that blockade of AT(1) receptor stimulation attenuated adipocyte dysfunction. However, the effects of AT(2) receptor stimulation on adipose tissue were not yet clear. In the present study, we examined the adipose tissue dysfunction in atherosclerotic apolipoprotein E knockout (ApoEKO) mice with AT(2) receptor deficiency.

METHODS

Male ApoEKO and AT(2) receptor/ApoE knockout (AT(2)/ApoEKO) mice at 6 weeks of age were treated with a normal diet or a high-cholesterol diet (HCD: 1.25% cholesterol). Markers for adipocyte differentiation and inflammation in adipose tissue were assayed with real-time reverse-transcription-PCR and western blot.

RESULTS

Compared with ApoEKO mice, AT(2)/ApoEKO mice with a normal diet showed only a decrease in expression of adiponectin and CCAAT/enhancer binding protein delta (C/EBPdelta) in epididymal adipose tissue without changes in body weight, adipose tissue weight, and adipocyte number even at 6 months of age. After HCD for 4 weeks, the weight of both epididymal and retroperitoneal adipose tissue in AT(2)/ApoEKO mice was greater than that in ApoEKO mice without a change in body weight. Plasma concentrations of cholesterol and fatty acids were higher in AT(2)/ApoEKO mice than in ApoEKO mice. In adipose tissue of AT(2)/ApoEKO mice, the adipocyte number was decreased and the expression of peroxisome proliferator-activated receptor gamma (PPARgamma), C/EBPalpha, and aP2 was lower than that in ApoEKO mice, in association with an increase in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity.

CONCLUSIONS

These results suggest that AT(2) receptor stimulation in adipose tissue is involved in the improvement of adipocyte differentiation and adipose tissue dysfunction in atherosclerotic model.

Reduced angiotensin II levels in the cerebrospinal fluid of patients with amyotrophic lateral sclerosis

BACKGROUND

Recent studies suggest that angiotensin II, a major substrate in the renin-angiotensin system, protects neurons through stimulation of its type 2 receptors. However, quite a few clinical studies of angiotensin II levels have shown their relation to disease severity in neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS).

AIMS OF THE STUDY

To clarify the significance of angiotensin II in ALS.

METHODS

We assayed angiotensin II concentrations in cerebrospinal fluid (CSF) samples from 23 patients with ALS, nine patients with spinocerebellar degeneration (SCD) and 24 control individuals. We evaluated the disability levels of patients with ALS using the Revised ALS Functional Rating Scale (ALSFRS-R) and calculated the disease progression rate (DPR).

RESULTS

CSF angiotensin II levels were significantly lower in the ALS group compared with that in the control group (P = 0.00864), and showed a significant positive correlation with scores on the ALSFRS-R, and a significant negative correlation with the DPR.

CONCLUSIONS

In the present study, we reveal for the first time that angiotensin II levels in the CSF from patients with ALS are significantly reduced and significantly associated with disease severity and progression rate. These findings suggest that reduced levels of intrathecal angiotensin II may play a role in ALS.

Angiotensin-converting enzyme (ACE) and ACE2 levels in the cerebrospinal fluid of patients with multiple sclerosis

BACKGROUND

We reported a reduction in the levels of angiotensin II in cerebrospinal fluid (CSF) from patients with multiple sclerosis (MS).

OBJECTIVE AND METHODS

To clarify the mechanism underlying this reduction, we assayed angiotensin-converting enzyme (ACE) and ACE2 concentrations along with angiotensin II concentrations in CSF samples from 20 patients with MS and 17 controls with non-neurological diseases.

RESULTS

ACE levels were significantly elevated in patients with MS compared with controls (48.42 +/- 4.84 vs 44.71 +/- 3.9 pg/mL), whereas ACE2 levels were significantly reduced (2.56 +/- 0.26 vs 2.78 +/- 0.24 pg/mL), acting toward a normalization of angiotensin II levels.

CONCLUSION

These results further indicate an alteration of the intrathecal renin-angiotensin system in patients with MS.

Characterization of dental pulp stem cells of human tooth germs

In previous studies, human dental pulp stem cells (hDPSCs) were mainly isolated from adults. In this present study, we characterized hDPSCs isolated from an earlier developmental stage to evaluate the potential usage of these cells for tissue-regenerative therapy. hDPSCs isolated at the crown-completed stage showed a higher proliferation rate than those isolated at a later stage. When the cells from either group were cultured in medium promoting differentiation toward cells of the osteo/odontoblastic lineage, both became alkaline-phosphatase-positive, produced calcified matrix, and were also capable of forming dentin-like matrix on scaffolds in vivo. However, during long-term passage, these cells underwent a change in morphology and lost their differentiation ability. The results of a DNA array experiment showed that the expression of several genes, such as WNT16, was markedly changed with an increasing number of passages, which might have caused the loss of their characteristics as hDPSCs.

Frequencies of PRNP gene polymorphisms in Vietnamese dairy cattle for potential association with BSE

Summary Since 2004, significant associations between bovine spongiform encephalopathy (BSE) susceptibility in cattle and frequencies of insertion/deletion (ins/del; indel) polymorphisms within the bovine prion protein gene (PRNP) have been reported. In this study, we investigated the frequencies of indel polymorphisms within two variable sites, a 23-bp indel polymorphism in the promoter region (23indel) and a 12-bp indel polymorphism in intron 1 region (12indel), in the PRNP in 206 Vietnamese dairy cattle and seven Japanese BSE-affected cattle. In Vietnamese dairy cattle, the frequency distributions of del allele and del/del genotypic polymorphisms in the 23indel site, which are thought to be associated with BSE susceptibility, were significantly higher, whereas the frequencies of del allelic and del/del genotypic polymorphisms in the 12indel site, which have been reported to confer BSE susceptibility, were significantly lower. We have provided evidence that Vietnamese dairy cattle have a unique genetic background in the PRNP gene in comparison with cattle or sires previously reported in other countries.

Blockade of AT1 receptor improves adipocyte differentiation in atherosclerotic and diabetic models

BACKGROUND

The roles of the angiotensin (Ang) II type 1 (AT(1)) receptor in the changes in white adipose tissue were explored in an animal model of atherosclerosis using apolipoprotein E-deficient (ApoEKO) mice.

METHODS

Apolipoprotein E-deficient (ApoEKO) mice and KK-A(y) mice were used. Expression of markers for adipocyte differentiation and inflammation was determined by real-time reverse-transcription polymerase chain reaction.

RESULTS

Adipose tissue weight and adipocyte size in epididymal white adipose tissue were increased in ApoEKO mice and KK-A(y) mice. In the adipose tissue of these models, expression of adiponectin and peroxisome proliferator-activated receptor-gamma (PPARgamma), which induce adipocyte differentiation, and expression of transcription factors of adipocyte differentiation, such as CCAAT-enhancer-binding protein-alpha (C/EBPalpha) and aP2, were decreased. Expression of inflammatory markers and nicotinamide adenine dinucleotide phosphate oxidase subunits was also increased. Deletion of AT(1)a receptor in ApoEKO mice and administration of an AT(1) receptor blocker, valsartan, to KK-A(y) mice reduced epididymal adipose tissue weight and adipocyte size significantly. Blockade of the AT(1) receptor also reduced the expression of inflammatory chemokines and oxidative stress markers. Moreover, AT(1)a receptor deletion in ApoEKO mice and AT(1) receptor blockade in KK-A(y) mice prevented the decrease in expression of adiponectin, PPARgamma, C/EBPalpha, and aP2. Valsartan also increased glucose uptake induced by insulin in adipose tissue of KK-A(y) mice.

CONCLUSIONS

These results suggest that enlargement and weakened differentiation of adipocytes are observed in atherosclerosis and diabetes, and that AT(1) receptor blockade prevented adipocyte enlargement and promoted adipocyte differentiation in these models.

Reduction of angiotensin II in the cerebrospinal fluid of patients with multiple sclerosis

We previously demonstrated that angiotensin II acts as a crucial neuroprotective factor after neural injury through angiotensin II type-2 (AT2) receptor signaling. Although the pathway is known to play an important role in the development of experimental autoimmune encephalomyelitis, cerebrospinal fluid (CSF) angiotensin II levels in patients with multiple sclerosis (MS) have never been studied. To clarify the significance of angiotensin II in MS, we assayed angiotensin II concentrations using an established enzyme-linked immunoabsorbent assay in CSF samples from patients with MS ( n = 21), patients with inflammatory neuropathies (IN) ( n = 23) and control individuals who did not have either of the neurological diseases or any other disease that might affect the angiotensin II levels in the CSF (control) ( n = 24). Angiotensin II levels in the CSF were 3.79 ± 1.54 pg/ml in the MS group, 5.13 ± 2.27 pg/ml in the IN group and 6.71 ± 2.65 pg/ml in the control group. The angiotensin II levels in the CSF of the MS group were significantly lower than in the control group ( p = 0.00057). Angiotensin II concentration in the CSF tended to have a negative correlation with the Kurtzke’s Expanded Disability Status Scale scores during MS relapse ( p = 0.0847). These findings suggest that reduced levels of intrathecal angiotensin II may be related to the abnormal neural damage and repair processes in MS.

Novel scaffold for cathepsin K inhibitors

Pyrrolopyrimidine, a novel scaffold, allows to adjust interactions within the S3 subsite of cathepsin K. The core intermediate 10 facilitated the P3 optimization and identified highly potent and selective cathepsin K inhibitors 11-20.

Species-specificity of a panel of prion protein antibodies for the immunohistochemical study of animal and human prion diseases

Monoclonal antibodies to the prion protein (PrP) have been of critical importance in the neuropathological characterization of PrP-related disease in men and animals. To determine the influence of species-specific amino-acid substitutions recognized by monoclonal antibodies, and to investigate the immunohistochemical reactivity of the latter, analyses were carried out on brain sections of cattle with bovine spongiform encephalopathy, sheep with scrapie, mice infected with scrapie, and human beings with Creutzfeldt-Jakob disease (CJD) or Gerstmann-Sträussler-Sheinker disease (GSS). Immunoreactivity varied between the antibodies, probably as the result of differences in the amino-acid sequence of the prion protein in the various species. Some monoclonal antibodies against mouse recombinant PrP gave strong signals with bovine, ovine and human PrP(Sc), in addition to murine PrP(Sc), even though the amino-acid sequences determined by the antibody epitope are not fully identical with the amino-acid sequences proper to the species. On the other hand, in certain regions of the PrP sequence, when the species-specificity of the antibodies is defined by one amino-acid substitution, the antibodies revealed no reactivity with other animal species. In the region corresponding to positions 134-159 of murine PrP, immunohistochemical reactivity or species-specificity recognized by the antibodies may be determined by one amino acid corresponding to position 144 of murine PrP. Not all epitopes recognized by a monoclonal antibody play an important role in antigen-antibody reactions in immunohistochemistry. The presence of the core epitope is therefore vital in understanding antibody binding ability.

Interacting molecule of AT1 receptor, ATRAP, is colocalized with AT1 receptor in the mouse renal tubules

The renin-angiotensin system in the kidney plays a critical role in the regulation of renal hemodynamics and sodium handling through the activation of vascular, glomerular and tubular angiotensin II type 1 (AT1) receptor-mediated signaling. We previously cloned a molecule that specifically bound to the AT1 receptor and modulated AT1 receptor signaling in vitro, which we named ATRAP (for AT1 receptor-associated protein). The purpose of this study is to analyze the renal distribution of ATRAP and to examine whether ATRAP is co-expressed with the AT1 receptor in the mouse kidney. We performed in situ hybridization, Western blot analysis, and immunohistochemistry to investigate the expression of ATRAP mRNA and protein in the mouse kidney. The results of Western blot analysis revealed the ATRAP protein to be abundantly expressed in the kidney. Employing in situ hybridization and immunohistochemistry, we found that both ATRAP mRNA and the protein were widely distributed along the renal tubules from Bowman's capsules to the inner medullary collecting ducts. ATRAP mRNA was also detected in the glomeruli, vasculature, and interstitial cells. In all tubular cells, the ATRAP protein colocalized with the AT1 receptor. Finally, we found that the dietary salt depletion significantly decreased the renal expression of ATRAP as well as AT1 receptor. These findings show ATRAP to be abundantly and broadly distributed in nephron segments where the AT1 receptor is expressed. Furthermore, this is the first report demonstrating a substantial colocalization of ATRAP and AT1 receptor in vivo.

Relationship between oxygenation in inactive biceps brachii muscle and hyperventilation during leg cycling

Inactive forearm muscle oxygenation has been reported to begin decreasing from the respiratory compensation point (RCP) during ramp leg cycling. From the RCP, hyperventilation occurs with a decrease in arterial CO2 pressure (PaCO2). The aim of this study was to determine which of these two factors, hyperventilation or decrease in PaCO2, is related to a decrease in inactive biceps brachii muscle oxygenation during leg cycling. Each subject (n = 7) performed a 6-min two-step leg cycling. The exercise intensity in the first step (3 min) was halfway between the ventilatory threshold and RCP (170+/-21 watts), while that in the second step (3 min) was halfway between the RCP and peak oxygen uptake (240+/-28 watts). The amount of hyperventilation and PaCO2 were calculated from gas parameters. The average cross correlation function in seven subjects between inactive muscle oxygenation and amount of hyperventilation showed a negative peak at the time shift of zero (r = -0.72, p<0.001), while that between inactive muscle oxygenation and calculated PaCO2 showed no peak near the time shift of zero. Thus, we concluded that decrease in oxygenation in inactive arm muscle is closely coupled with increase in the amount of hyperventilation.

Sensitivity to cisplatin determined by the histoculture drug response assay and clinical response of endometrial cancer

This study investigated the value of the in vitro histoculture drug response assay (HDRA) for predicting the efficacy of chemotherapy in patients with endometrial cancer. Specimens were obtained from 115 patients with endometrial cancer treated at Keio University Hospital between 1994 and 2002. Tumor fragments were cultured on collagen sponge gel with cisplatin for 7 days, and cell viability was assessed. The cutoff value of the 50% inhibitory concentration of cisplatin was set at 23 microg/mL. Sensitivity of stage III or IV disease to chemotherapy was investigated, and differences of 5-year progression-free survival between patients with sensitive and resistant tumors were evaluated by the Kaplan-Meier method. Tumors were evaluable in 93.0% of patients (107/115). Among 38 patients in stages III or IV, 23 received chemotherapy containing cisplatin. Seven sensitive tumors did not recur, while recurrence/progression occurred within 6 months in 8/16 patients with tumors showing low sensitivity. Among stages III and IV patients, there was a significant difference of 5-year progression-free survival (P < 0.05) between those with tumors showing high or low sensitivity. Accordingly, the HDRA may predict the efficacy of chemotherapy for endometrial cancer.

Chemosensitivity testing of ovarian cancer using the histoculture drug response assay: sensitivity to cisplatin and clinical response

Despite cytoreductive surgery and chemotherapy, the prognosis of advanced ovarian cancer is still poor. Predicting the chemosensitivity of tumors might improve the outcome. Therefore, we investigated the clinical value of the histoculture drug response assay for ovarian cancer. Tumor specimens were cultured for 7 days on collagen gel sponge in medium containing cisplatin, and the 50% inhibitory concentration was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide assay. Then the in vitro sensitivity to cisplatin was compared with the clinical response and survival. Apoptosis of tumor cells was also investigated. Among 173 ovarian cancer patients, 164 were evaluable by the assay, and 29 patients had measurable lesions for which the clinical response could be determined. The 5-year survival rate was significantly higher in patients with chemosensitive tumors than in those with chemoresistant tumors when the cutoff value was set at a 50% inhibitory concentration of 25 microg/mL and the accuracy of the assay was 82.8% (24/29). As chemosensitivity to cisplatin became greater, the number of apoptotic cells also increased. This chemosensitivity assay may help predict the clinical response to cisplatin-based chemotherapy, thus improving the survival of ovarian cancer patients.

Bovine Posterior Pituitary Extract Stimulates Prolactin Release from the Anterior Pituitary Gland In Vitro and In Vivo in Cattle

It has been reported that the posterior pituitary (PP) gland contains a potent, unknown prolactin (PRL)-releasing factor (PRF) in rats. PRFs are assumed to be produced in neurones located within the hypothalamus, and to be peptidergic in nature. However, little is known about PRFs in domestic animals. To characterize the PRF in the PP of domestic animals, the present study examined the PRL-releasing activity of an acidic extract from bovine PP (bPP) in vitro and in vivo in cattle. First, the PRL-releasing effect of bPP extract was compared with that of PRL-releasing peptide (PrRP), and thyrotropin-releasing hormone (TRH) from cultured bovine anterior pituitary cells. The extract significantly increased PRL concentrations in the culture medium, at doses of 0.002 and 0.02 eq./ml (one eq. is the PP extract from one animal), compared with the control (p < 0.05). PrRP failed to stimulate the release of PRL. TRH significantly increased PRL concentrations in the culture medium, at doses from 10(-9) to 10(-7) M, compared with the control (p < 0.05). The rate of increase in the PRL concentration, by 0.02 eq./ml bPP extract, was significantly greater than that in TRH (p < 0.05). Secondly, plasma PRL responses to the intravenous (i.v.) injection of bPP extract (0.5 eq./head), PrRP [3.59 mug/kg body weight (BW)], TRH (1 mug/kg BW), and a dopamine receptor antagonist (sulpiride, 0.1 mg/kg BW), were examined in calves. PrRP failed to stimulate PRL release; however, plasma PRL increased immediately following the injection of bPP extract, TRH and sulpiride. The PRL-releasing effect of i.v. injections of TRH and sulpiride was more potent than that of bPP extract. Finally, plasma PRL responses to the intra-hypothalamic injection of bPP extract were examined in calves. The intra-hypothalamic infusion (arcuate nucleus) of 0.0625 eq./head of bPP extract strongly stimulated PRL release in calves (p < 0.05). The present results show that PP contains a physiologically potent PRF in cattle.

Relationship between maximal oxygen uptake and oxygenation level in inactive muscle at exhaustion in incremental exercise in humans

The aim of the present study was to determine whether the oxygenation level in an inactive muscle during an incremental exercise test, determined by near-infrared spectroscopy, influences the maximal oxygen uptake (Vo2max). The oxygenation level at the onset of incremental exercise was higher than that at rest and started to decrease at a high power output. A minimal level was observed at exhaustion during incremental exercise. Vo2 increased linearly after some delay, and the rate of increase in Vo2 was greater at a higher power output. Heart rate increased linearly after the time delay, and the rate of increase in heart rate did not change. There was a significant correlation between Vo2max and oxygenation level in inactive muscle at exhaustion (r=-0.89). We therefore concluded that the oxygenation level in inactive muscle at exhaustion during incremental exercise is associated with an individual difference in Vo2max.

Chemosensitivity testing of ovarian cancer using the histoculture drug response assay: sensitivity to cisplatin and clinical response

Despite cytoreductive surgery and chemotherapy, the prognosis of advanced ovarian cancer is still poor. Predicting the chemosensitivity of tumors might improve the outcome. Therefore, we investigated the clinical value of the histoculture drug response assay for ovarian cancer. Tumor specimens were cultured for 7 days on collagen gel sponge in medium containing cisplatin, and the 50% inhibitory concentration was determined by the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyltetrazolium bromide assay. Then the in vitro sensitivity to cisplatin was compared with the clinical response and survival. Apoptosis of tumor cells was also investigated. Among 173 ovarian cancer patients, 164 were evaluable by the assay, and 29 patients had measurable lesions for which the clinical response could be determined. The 5-year survival rate was significantly higher in patients with chemosensitive tumors than in those with chemoresistant tumors when the cutoff value was set at a 50% inhibitory concentration of 25 μg/mL and the accuracy of the assay was 82.8% (24/29). As chemosensitivity to cisplatin became greater, the number of apoptotic cells also increased. This chemosensitivity assay may help predict the clinical response to cisplatin-based chemotherapy, thus improving the survival of ovarian cancer patients.

Relationship between maximal oxygen uptake and oxygenation level in inactive muscle at exhaustion in incremental exercise in humans

The aim of the present study was to determine whether the oxygenation level in an inactive muscle during an incremental exercise test, determined by near-infrared spectroscopy, influences the maximal oxygen uptake (Vo2max). The oxygenation level at the onset of incremental exercise was higher than that at rest and started to decrease at a high power output. A minimal level was observed at exhaustion during incremental exercise. Vo2 increased linearly after some delay, and the rate of increase in Vo2 was greater at a higher power output. Heart rate increased linearly after the time delay, and the rate of increase in heart rate did not change. There was a significant correlation between Vo2max and oxygenation level in inactive muscle at exhaustion (r = -0.89). We therefore concluded that the oxygenation level in inactive muscle at exhaustion during incremental exercise is associated with an individual difference in Vo2max.

Experimental transmission of abnormal prion protein (PrPsc) in the small intestinal epithelial cells of neonatal mice

Using an immunohistochemical method, we attempted to detect the transmission of abnormal prion protein (PrPsc) to the enterocytes of the small intestine of neonatal mice by oral exposure with sheep brain affected by scrapie. Five 1-day-old neonatal mice were exposed by oral inoculation to the homogenized brain of a scrapie-affected sheep. In the small intestine of all mice 1 hour after inoculation, immunoreactivity with antinormal prion protein (PrPc) antibody was seen in the cytoplasm of villus enterocytes. This finding suggests transmission of abnormal PrPsc into the cytoplasm of enterocytes. In control mice treated with normal sheep brain, no PrPc signal was seen in enterocytes of the small intestine. Immunopositivity for neurofilament protein and glial fibrillary acidic protein was seen in the cytoplasm of enterocytes of mice inoculated with scrapie and normal sheep brain. This suggests that the enterocytes of neonatal mice can absorb PrPsc and other macromolecular proteins of the sheep brain affected by scrapie and may be more important than previously thought as a pathway for PrPsc transmission in neonatal animals.

Effects of Ghrelin on growth hormone secretion from cultured adenohypophysial cells in pigs

To clarify the direct effects of Ghrelin on growth hormone (GH) release from anterior pituitary (AP) cells in pigs, GH-releasing effects of human Ghrelin (hGhrelin) and rat Ghrelin (rGhrelin) on porcine AP cells were compared with GHRH in vitro. The AP cells were obtained from 6-month-old pigs and the cells (2 x 10(5) cells per well) were incubated for 2 h with the peptides after incubating in DMEM for 3 days. hGhrelin and rGhrelin significantly stimulated GH release from the cultured cells at doses of 10(-8) and 10(-7)M (P < 0.05). The rates of increase in GH at 10(-8) and 10(-7)M of hGhrelin were 82.7 and 131.9%, while those with rGhrelin were 43.9 and 79.5%, respectively. GHRH significantly stimulated GH release from the cells at a dose as low as 10(-11)M (P < 0.05), and the response to GHRH was greater than that induced by Ghrelins. In time-course experiments, GHRH continued to increase GH concentrations in media until 120 min after incubation; however, those in media treated with hGhrelin reached a plateau 60 min after incubation, and the maximal value was approximately one third that obtained with GHRH. When hGhrelin (10(-8)M) and GHRH (10(-8)M) were added together, additive effects of both peptides on the release of GH were observed (P < 0.05). Somatostatin (SS, 10(-7)M) significantly blunted GH release induced by hGhrelin (10(-8)M) and GHRH (10(-8)M) (P < 0.05). In the presence of SS, additive effects of hGhrelin and GHRH on the release of GH were observed (P < 0.05). These results show that Ghrelin directly stimulates GH release from anterior pituitary cells in pigs; however, the GH-releasing effect is weaker than that of GHRH in vitro. The present results also show that Ghrelin interacts with GHRH and SS to in the release of GH from porcine adenohypophysial cells.

Kinetics of CO(2) excessive expiration in constant-load exercise

BACKGROUND

The purpose of this study was to examine the kinetics of excessively expired CO(2) (VCO(2) excess) in response to an increase in blood lactate (La) during constant-load exercise.

METHODS

O(2) uptake (VO(2) ) and CO(2) output (VCO(2) ) were measured at exercise intensities of 55% and 70% of individual peak values of Vo2 obtained in incremental exercise. VCO(2) excess was obtained by multiplying the Vo2 obtained at 55% or 70% peakVoz by the difference between respiratory gas exchange ratios (VCO(2) /Vo(2) ) at 55% or 70% peak VO(2) and at 40% peakVO(2) .

RESULTS

In both exercises of 55% and 70% peakVO(2) , VCO(2) excess remained constant for about the first minute, increased until about 2 min after the start of exercise, and then decreased. VCO(2) excess showed positive values even at 10 min after the start of exercise. The La level, on the other hand, increased during the first 5 min of exercise but did not show any significant change during the next 5 min. The values of VCO(2) excess were integrated from the start to the end of 10 min of exercise (CO(2) excess). CO(2) excess was found to be significantly related to the difference between La at 10 min after the start of exercise and at rest (DLa). End tidal CO(2) pressure (PETCO(2)) increased and then decreased in both exercises. The difference between PETCO(2) values at peak and at 10 min after the start of exercise (DPETCO(2) ) was significantly related to CO(2) excess. DPetco2 was also found to be significantly related to the increase in DLa.

CONCLUSIONS

The kinetics of estimated VCO2excess is affected first by the increase in La and later by the decrease in PETCO(2) induced by the La increase.

Simultaneous resection of pancreas and liver metastases from different metachronous primary cancers

Resection of a pancreatic head tumor and partial resection of the liver for metastatic lesions were carried out simultaneously in a 72-year-old woman. The patient had a history of two previous operations, right nephrectomy for renal cell carcinoma (clear cell type), done 14 years previously, and an Autincloss procedure for cancer of the left breast (solid tubular carcinoma); (T1N0M0; stage I) done 7 years previously. At the current presentation, preoperative radiographic examination showed a hypervascular tumor in each of the pancreatic and hepatic lesions, but with different patterns. On the basis of histological findings in the two resected specimens, it was difficult to establish whether the hepatic tumor originated from the renal cell carcinoma or the breast cancer, but postoperative immunohistochemical studies for carcinoembryonic antigen (CEA), estrogen receptors, and gross cystic disease fluid protein (GCDFP)-15 showed that the pancreatic tumor had metastasized from the renal cell carcinoma, and the liver tumor from the breast cancer. The immunohistochemical investigation of different markers thus proved to be useful in making the final diagnosis of metastatic lesions from different and metachronous cancers.

[The new portable system for home enteral nutrition, Portermate, made a patient possible go out for a long time: report of a case]

The patient, who is received home enteral nutrition (HEN) for a long time in a day, has problems on moving all days. Now, we tried Portermate, which is new portable devices for HEN, in his clinical care. The patient is chronic pancreatitis, and his clinical problems becomes to be worse after he ate. He was under total enteral nutrition via jejunostomy. His clinical complications were almost controlled after HEN, but he has a few complains receiving enteral nutrition. He would not move easily, for an old HEN system was not compact to move. Portermate made him go everywhere he wanted any time. It extremely improved his QOL under HEN. He continues to use Portermate.

An autopsy case of hemilaterally dominant and systematic/extensive border zone infarction: sequela of preceding atherosclerotic obstruction of one common carotid artery followed by repeated episodes of systemic hypotension

A 68-year-old man was admitted to St Marianna University Hospital on account of loss of consciousness with left hemiplegia. During the hospital recovery course with a rehabilitation procedure, the patient's blood pressure was very unstable, fluctuating between high (210/110 mmHg) and low (110/70 mmHg) values accompanied by a fainting sensation. A second stroke of left hemiplegia took place 1 month later. Afterwards, his condition worsened to tetraplegia with dysarthria. Three months later, lung cancer with multiple metastasis including his left neck was found and he died from adynamic ileus 6 months after the onset of the present illness. Autopsy revealed nearly complete atheromatous obstruction and more than 50% stenosis, respectively, of his right common and internal/external carotid arteries. His intracranial arterial trunks and main branches were all patent with localized atherosclerosis of only moderate degree. The pathology of the brain existed predominantly in the right hemisphere in the border zone area between the anterior and middle cerebral arteries systematically with numerous disseminated foci of complete or incomplete necrosis, white matter and gray matter being involved independently. Involvement of centrum semiovale white matter is more extensive and intensive than that of gray matter. Of the gray matter, cerebral cortex as well as striatum, periventricular (the third ventricle) gray and cerebellar cortex was involved. The specific characteristic topography and distribution of the lesions together with their histopathology are described in detail with illustration. It is concluded that this case represents an outstanding example of hemodynamic cerebral circulatory insufficiency doubly caused by hemilateral carotid artery stenosis and repeated episodes of systemic hypotension.

Roles of angiotensin II type 2 receptor stimulation associated with selective angiotensin II type 1 receptor blockade with valsartan in the improvement of inflammation-induced vascular injury

BACKGROUND

To investigate the effect of angiotensin (Ang) II type 1 receptor (AT(1)) blocker on vascular remodeling and explore the possibility of the involvement of Ang II type 2 receptor (AT(2)) stimulation in this process, we examined the effects of the selective AT(1) blocker valsartan on the vascular injury in wild-type (Agtr2+) and AT(2)-null (Agtr2-) mice.

METHODS AND RESULTS

Neointima formation and the proliferation of vascular smooth muscle cells (VSMCs) induced by cuff placement on the femoral artery were greater in Agtr2- mice than those in Agtr2+ mice. Treatment of mice with valsartan at a dose of 1 mg. kg(-1). d(-1), which did not influence systolic blood pressure, significantly decreased neointima formation and the proliferation of VSMCs, whereas the valsartan was less effective in Agtr2- mice. Moreover, cuff placement increased the expression of monocyte chemoattractant protein-1 (MCP-1); inflammatory cytokines such as tumor necrosis factor (TNF)-alpha, interleukin (IL)-6, and IL-1beta; and infiltration of CD45-positive leukocytes and macrophages in the injured arteries and further enhanced them in Agtr2- mice, suggesting the antagonistic effects of AT(1) and AT(2) for vascular inflammation. Valsartan attenuated the expression of MCP-1, TNF-alpha, IL-6, IL-1beta, and infiltration of leukocytes and macrophages in the injured arteries; however, these effects of valsartan were less prominent in Agtr2- mice.

CONCLUSIONS

These results suggest that the stimulation of the AT(2) receptor after AT(1) blockade is important in the improvement of the inflammatory vascular injury.

Polypeptide synthesis using an expressed peptide as a building block for condensation with a peptide thioester: application to the synthesis of phosphorylated p21Max protein(1-101)

An expressed peptide proved to be useful as a building block for the synthesis of a polypeptide via the thioester method. A partially protected peptide segment, for use as a C-terminal building block, could be prepared from a recombinant protein; its N-terminal amino acid residue was transaminated to an alpha-oxoacyl group, the side-chain amino groups were then protected with t-butoxycarbonyl (Boc) groups, and. finally, the alpha-oxoacyl group was removed. On the other hand, an O-phosphoserine-containing peptide thioester was synthesized via a solid-phase method using Boc chemistry. These building blocks were then condensed in the presence of silver ions and an active ester component. During the condensation, epimerization at the condensation site could be suppressed by the use of N,N-dimthylformamide (DMF) as a solvent. Using this strategy, a phosphorylated partial peptide of the p21Max protein, [Ser(PO3H2)2.11]-p21Max(1-101), was successfully synthesized.

[A case of elderly onset Parkinson's disease complicated by dropped head syndrome]

An 86-year old man presented with a 7-year history of gait disturbance. He was admitted to our hospital on April 2000 because he was experiencing difficulty eating due to progression of dropped head syndrome. Upon standing and sitting, remarkable dropped head and kyphosis were observed. When lying, the patient was able to stretch his neck, and he could stand and walk with the aid of a walker. Rigidity and resting tremor were present predominantly in the lower limbs. Parkinson's disease was diagnosed therefore L-dopa and Cabergoline were administered. Parkinsonism and dropped head syndrome improved in response to treatment. Cases involving dropped head syndrome due to Parkinson's disease are reportedly improved by L-dopa, but exasperated by dopamine agonists. The mechanism of dropped head is thought to be an imbalance in the tonus of the anterior and posterior neck muscles. Dropped head in the present case may have been a complication of Parkinson's disease since it improved in response to L-dopa.

Angiotensin II type 2 receptor inhibits epidermal growth factor receptor transactivation by increasing association of SHP-1 tyrosine phosphatase

Angiotensin (Ang) II has 2 major receptor isoforms, Ang type 1 (AT(1)) and Ang type (AT(2)). AT(1) transphosphorylates epidermal growth factor receptor (EGFR) to activate extracellular signal-regulated kinase (ERK). Although AT(2) was shown to inactivate ERK, the action of AT(2) on EGFR activation remains undefined. Using AT(2)-overexpressing vascular smooth muscle cells from AT(2) transgenic mice, we studied these undefined actions of AT(2). Maximal ERK activity induced by Ang II was increased 1.9- and 2.2-fold by AT(2) inhibition, which was abolished by orthovanadate but not okadaic acid or pertussis toxin. AT(2) inhibited AT(1)-mediated EGFR tyrosine phosphorylation by 63%. The activity of SHP-1 tyrosine phosphatase was significantly upregulated 1 minute after AT(2) stimulation and association of SHP-1 with EGFR was increased, whereas AT(2) failed to tyrosine phosphorylate SHP-1. Stable overexpression of SHP-1-dominant negative mutant completely abolished AT(2)-mediated inhibition of EGFR and ERK activation. AT(1)-mediated c-fos mRNA accumulation was attenuated by 48% by AT(2) stimulation. Induction of fibronectin gene containing an AP-1 responsive element in its 5'-flanking region was decreased by 37% after AT(2) stimulation, corresponding to the results of gel mobility assay with the AP-1 sequence of fibronectin as a probe. These findings suggested that AT(2) inhibits ERK activity by inducing SHP-1 activity, leading to decreases in AP-1 activity and AP-1-regulated gene expression, in which EGFR dephosphorylation plays an important role via association of SHP-1.

Glycidol degrades scrapie mouse prion protein

Agents of transmissible spongiform encephalopathy (prion) are known to be extremely resistant to physicochemical inactivation procedures such as heat, radiation, chemical disinfectants such as detergents, alcohols, glutaraldehyde, formalin, and so on. Because of its remarkable resistance, it is difficult to inactivate prion. Chemical inactivation seems to be a practical method because it is applicable to large or fixed surfaces and complicated equipment. Here, three epoxides: beta-propiolactone, propylene oxide, and glycidol (GLD) were examined of their inactivation ability against scrapie-mouse prion protein (PrP(Sc)) under various conditions of chemical concentration, incubation time, and temperature. Among these chemicals, GLD worked most effectively and degraded PrP into small fragments. As a result of the bioassay, treatment with 3% GLD for 5 hr and 5% GLD for 2, 5 hr or 12 hr at room temperature prolonged the mean incubation time by 44, 30, 110 and 73 days, respectively. From dose-incubation time standard curve, the decrease in infectivity titers were estimated as 10(3) or more. Therefore, degradation of PrP(Sc) by GLD decreased the scrapie infectivity. It is also suggested that pH and salt concentrations influence the effect of GLD. Although further study is necessary to determine the optimal condition, GLD may be a potential prion disinfectant.