Effect of soymilk consumption on serum estrogen and androgen concentrations in Japanese men

Soy consumption has been associated with a reduced risk of prostate cancer. The mechanism for this association may involve the effect of soy on the endocrine system. We conducted a randomized dietary intervention study to determine the effects of soy consumption on serum levels of steroid hormones in men. Thirty-five men were randomly assigned to either a soymilk-supplemented group or a control group. The men in the soy-supplemented group were asked to consume 400 ml of soymilk daily for 8 weeks. The men in the control group maintained their usual diet. Blood samples were obtained just before the initiation of the dietary period and thereafter every two weeks for 12 weeks. Changes in hormone concentrations were analyzed and compared between the two groups using the mixed linear regression model against weeks from the start of the dietary period. The mean (SD) soymilk intake estimated from dietary records during the dietary study period was 342.9 (SD, 74.2) ml in the soymilk-supplemented group. There was a significant difference between the two groups in terms of changes in serum estrone concentrations, which tended to decrease in the soy-supplemented group and increase in the control group over time. None of the other hormones measured (estradiol, total and free-testosterone, or sex hormone-binding globulin) showed any statistical difference between the two groups in terms of patterns of change. The results of the study indicate that soymilk consumption may modify circulating estrone concentrations in men.

Primary biliary cirrhosis associated with idiopathic retroperitoneal fibrosis

Idiopathic retroperitoneal fibrosis (IRF) and primary biliary cirrhosis (PBC) are distinct clinical disorders which rarely occur in the same patient. We report a 79-year-old man with the coexistence of both conditions. The patient had antibodies to both centromere and mitochondria, as indicated by indirect immunofluorescence. Diagnoses of IRF and PBC were confirmed histologically. Although the association between IRF and PBC is obscure, IRF may be involved in many autoimmune diseases associated with PBC.

Involvement of 1,2-diacylglycerol in improvement of heart function by etomoxir in diabetic rats

Abnormal lipid metabolism has been proposed to be involved in the pathogenesis of diabetic cardiomyopathy. In this study, we measured myocardial lipid levels, including 1,2-diacylglycerol (1,2-DAG) and ceramide (CM), and myocardial function in diabetic rats. We also evaluated the effects of etomoxir (ETM), a carnitine palmitoyl transferase I inhibitor, on diabetic rat hearts from the viewpoints of alterations in lipid second messengers and myocardial function. Rats were injected with streptozotocin (60 mg/kg) to induce diabetes and were treated 5 weeks later with ETM (18 mg/kg) for 8 days. In diabetic rats, heart rate, systolic blood pressure, and fractional shortening were significantly reduced compared with those in controls. Treatment of diabetic rats with ETM ameliorated myocardial dysfunction other than heart rate. Myocardial 1,2-DAG levels in diabetic rats were significantly elevated compared with those in controls, while myocardial CM levels were not. ETM treatment caused an additional increase in myocardial 1,2-DAG levels in diabetic rats, but the CM levels did not change. There was a marked difference in fatty acid pattern of 1,2-DAG between diabetic and ETM-treated diabetic rat hearts. The fatty acids 18:1 and 18:2 were significantly increased and the fatty acids 16:0, 18:0, 20:4, and 22:6 were significantly reduced in ETM-treated diabetic rat hearts. These data suggest 1,2-DAG is involved in ameliorating myocardial dysfunction in diabetic rats and that its source is different between diabetic and ETM-treated diabetic rats. CM is unlikely to be involved in the pathogenesis of diabetic cardiomyopathy or the improvement of cardiac contractility in diabetic rats by ETM.

Measurement of cerebral hemodynamics with perfusion-weighted MR imaging: comparison with pre- and post-acetazolamide 133Xe-SPECT in occlusive carotid disease

BACKGROUND AND PURPOSE

We generated regional cerebral blood volume (rCBV) and regional cerebral blood flow (rCBF) studies from dynamic susceptibility contrast-enhanced MR images after an intravenous bolus injection of contrast agent (perfusion-weighted imaging [PWI]) by applying indicator dilution theory. We used a multishot echo-planar imaging (EPI) sequence to obtain adequate arterial input function (AIF). Our purpose was to compare the cerebral hemodynamics measured by PWI with the rCBF values and cerebral perfusion reserve obtained by xenon-133 single-photon emission CT (133Xe-SPECT).

METHODS

Eight patients with chronic internal carotid artery occlusion or stenosis were examined. PWI data were acquired using a multishot EPI sequence, and the AIF was determined automatically. Our procedure was based on indicator dilution theory and deconvolution analysis. To eliminate the effect of superficial vessels, the automatic threshold selection method was used.

RESULTS

AIF was adequate to generate rCBF and rCBV images. The rCBF and rCBV images by PWI were superior to 133Xe-SPECT scans in spatial resolution, and the rCBF values obtained by PWI correlated well with those obtained by 133Xe-SPECT. The regions with severely decreased perfusion reserve, which were determined by pre- and post-acetazolamide 133Xe-SPECT, showed significantly lower rCBF and higher rCBV by PWI than did regions with normal and moderately decreased perfusion reserve.

CONCLUSION

The rCBF and rCBV images generated by our procedure using PWI data appear to provide important clinical information for evaluating the degree of cerebral perfusion reserve impairment in patients with chronic ischemia.

Changes in titers of antimitochondrial and antinuclear antibodies during the course of primary biliary cirrhosis

A case of primary biliary cirrhosis (PBC) in whom a complete biochemical (serum bilirubin, transaminases and alkaline phosphatase) remission was noted after combination treatment with ursodeoxycholic acid (UDCA) and corticosteroid is reported. The antimitochondrial antibody (AMA) detected by indirect immunofluorescence was initially positive, and the antinuclear antibody (ANA) was negative, but these two antibodies subsequently fluctuated independently (AMA-positive/ANA-negative, AMA-negative/ANA-negative, AMA-negative/ANA-positive, AMA-positive/ANA-positive, and again AMA-negative/ANA-positive) in spite of a lack of histopathological improvement in the liver after treatment. The clinical presentation in our case suggests that in some cases the diagnosis of PBC or so-called autoimmune cholangitis (AIC) might depend on the 'phase' of the same disease. Our results also suggest that detailed immunoreactive profiles against 2-oxo-acid dehydrogenase complex (2-OADC) enzymes by using immunoblotting, together with a serial histological examination, should provide more precise information for a diagnosis of PBC.

Ascorbic acid improves postischemic vasodilatation impaired by infusion of soybean oil into canine iliac artery

This study was conducted to (a) assess postischemic vasodilatation by changes in the vascular cross-sectional area using simultaneous intravascular two-dimensional and Doppler ultrasound before and after the infusion of Intralipid (Pharmacia & Upjohn, Peapack, NJ, U.S.A.); (b) evaluate how antioxidant ascorbic acid modifies the effects of Intralipid on postischemic vasodilatation: and (c) clarify the changes in plasma nitrite and nitrate (NOx-) levels after the infusion of Intralipid with and without ascorbic acid. Twenty-eight mongrel dogs were used to measure for vascular cross-sectional area and average instantaneous peak velocity in the iliac arteries after the 5-min occlusion of the arteries. Postischemic vasodilatation was impaired after the infusion of Intralipid (20%, 2 ml/kg) and this impaired response was reversed by the co-administration of ascorbic acid (30 mg/kg). NG-monomethyl-L-arginine completely abolished postischemic vasodilatation. Plasma NOx levels were significantly reduced after the infusion of Intralipid compared with baseline (11.6+/-0.4 vs. 12.9+/-0.3 microM, p = 0.025) and after infusion of Intralipid with ascorbic acid compared with baseline (11.8+/-0.5 vs. 13.1+/-0.4 microM, p = 0.047). We concluded that ascorbic acid reverses the endothelial dysfunction induced by Intralipid without increasing plasma NOx- levels and that deactivation of nitric oxide by oxidative stress is a primary contributor to Intralipid-induced impaired vasodilation.

Tc-99m PMT hepatobiliary scintigraphy in the differential diagnosis of extrahepatic metastases and hepatocellular carcinoma

PURPOSE

The authors evaluated the utility of hepatobiliary scintigraphy for tissue characterization of extrahepatic metastases from hepatocellular carcinoma (HCC) using Tc-99m N-pyrydoxyl-5-methyltriptophane (Tc-99m PMT).

METHODS

We examined 13 patients with HCC (29 extrahepatic metastases and 3 benign bone lesions) and 5 patients with other cancers (15 extrahepatic metastases). Thirty minutes to 6 hours after intravenous administration of Tc-99m PMT, planar (all 47 lesions) and SPECT (42 lesions) images were obtained. Accumulation of Tc-99m PMT in the lesion was evaluated visually by comparing bone scintigraphy, computed tomography, magnetic resonance imaging, or all of these.

RESULTS

Findings were positive in 12 of 13 patients with HCC and extrahepatic metastases (16 of 29 on planar imaging and 21 of 26 on SPECT). Findings in all three benign bone lesions and 15 metastatic lesions from non-HCC primary lesions were negative (0 of 18 on planar imaging, 0 of 16 on SPECT). There were no false-positive findings in these lesions. Lesion-by-lesion sensitivity, specificity, accuracy, and positive and negative predictive values were 55%, 100%, 72%, 100%, and 58% by planar imaging and 81%, 100%, 88%, 100%, and 76% by SPECT, respectively.

CONCLUSIONS

Because of the high specificity and reasonable sensitivity, Tc-99m PMT appears to be useful for the differential diagnosis of extrahepatic metastases from HCC. SPECT improves the detectability of small or faint accumulation in metastases from HCC.

Structure-affinity relationships of C-terminal cyclic analogue of neuropeptide Y for the Y1-receptor

We previously reported that a cyclic octapeptide amide, c[D-Cys29, Cys-34]NPY Ac-29-36 (YM-42454) showed a high affinity for Y1-receptors in SK-N-MC cells (Ki=0.047,microM) but not for Y2-receptors in the porcine hippocampus membranes (Ki>10microM). To explore the critical residues of this unique cyclic peptide for Y1-binding activity, the structure-affinity relationships were investigated by means of amino acid replacement. The results indicated that the hydrophobic side-chains of Leu30 and Ile31, the guanidinium groups of Arg33 and Arg33, and the C-terminal amide are critical for the binding affinity of YM-42454 to the Y1-receptor. On the other hand, Thr32 in YM-42454 might not be critical for the Y1-binding affinity. 1H-NMR studies for YM-42454 and its derivatives have suggested that the critical residues are involved in the direct interaction with a Y1-receptor rather than in maintaining the bioactive conformation.

Double-injection method for sequentially measuring cerebral blood flow with N-isopropyl-(123I)p-iodoamphetamine

We investigated the accuracy of a double-injection method for sequentially measuring cerebral blood flow (CBF) with N-isopropyl-(123I)p-iodoamphetamine (IMP) in simulation studies based on patient data and in clinical studies. The unidirectional clearance of IMP from the blood to the brain (K1; nearly equal to CBF) in the first and second sessions was calculated by means of a microsphere model. The K1 values in the first session (K1I) were calculated from Cb(5)/Int_CaI, where Cb(5) and Int_CaI are values for brain radioactivity 5 min after the first injection and for arterial blood radioactivity obtained by 5-min continuous sampling. The K1 values in the second session (K1II) were calculated by means of the following four methods. Method 1: [Cb(tz + 5) - Cb(tz)]/[Int_CaII - Ca(tz) x 5], where Cb(tz+5) and Cb(tz) are the brain radioactivity levels 5 min after the second injection and at the time the second session was started (tz), respectively. Int_CaII and Ca(tz) are the arterial blood radioactivity levels obtained by 5-min continuous sampling after the second injection and at tz, respectively. Method 2: [Cb(tz + 5) - Cb(tz)]/[Int_CaI x R], where R is the injection dose ratio. Method 3: [Cb(tz + 5) - Cb(tz) x exp(- K1I x 5/lambda)]/Int_CaII, where lambda is the population averaged partition coefficient. Method 4: same as Method 3 except that K1I was replaced by K1II obtained by means of Method 2. Theoretically, Method 4 appeared to be the best of the four methods. The change in K1 during the second session obtained by Method 1 or 2 largely depended on R and tz, whereas Method 3 or 4 yielded a more reliable estimate than Method 1 or 2, without largely depending on R and tz. Since Method 2 was somewhat superior to other methods in terms of noninvasiveness and simplicity, it also had the potential for routine clinical use. The reproducibility of two sequential measurements of K1 was investigated with clinical data obtained without any intervention. The response of CBF to acetazolamide challenge was also assessed by the above four methods. The knowledge gained by this study may assist in selecting a method for sequentially measuring CBF with a double injection of IMP.

Assessment of liver function in chronic liver diseases and regional function of irradiated liver by means of 99mTc-galactosyl-human serum albumin liver scintigraphy and quantitative spectral analysis

Scintigraphy with 99mTc-diethylenetriamine pentaacetic acid galactosyl human serum albumin (99mTc-GSA) was performed on 102 patients, then the hepatic extraction fraction (HEF), the rate constant for liver uptake of the tracer from the blood (K1) and the hepatic blood flow index (HBFI) were determined by spectral analysis. The HEF, K1 and HBFI values correlated moderately or closely with various indices of hepatic function, and the HEF and K1 values decreased according to the stage of liver dysfunction. The HEF and K1 values linearly and nonlinearly correlated with HH15 and LHL15, respectively. The HEF, K1 and HBFI values for the irradiated portion of 20 patients before and alter irradiation were compared. The HEF value in patients with a cirrhotic liver significantly (p < 0.002) decreased compared with that in patients with a normal liver at a dose of less than 40 Gy, whereas the HBFI value in patients with a normal liver significantly (p < 0.05) decreased compared with that in patients with a cirrhotic liver at a dose of 40 Gy or greater. This method appears to be a simple, non-invasive and useful tool with which to quantitatively evaluate liver function and it also helps clarify changes in regional function of the irradiated liver.

Design of the Y1-receptor-selective cyclic peptide based on the C-terminal sequence of neuropeptide Y

We designed four cyclic peptides which are mimics of the C-terminal region of human neuropeptide Y (NPY) on the basis of the structural model of NPY. One of these cyclic peptides, c[D-Cys29-L-Cys34]NPY Ac-29-36 (YM-42454), exhibited significantly higher affinity for the Y1-receptor than the corresponding C-terminal linear fragment, NPY Ac-28-36. Interestingly, YM-42454 showed binding affinity for the Y1-receptor in spite of the lack of the N-terminal sequence of NPY, whereas it did not show any binding affinity for the Y2-receptor. This conformationally restricted Y1-selective peptide would provide some insights into the bioactive conformation of the C-terminal region of NPY.

5-day vs. 7-day triple therapy with rabeprazole, clarithromycin and amoxicillin for Helicobacter pylori eradication

AIM

To determine whether a 5-day regimen with rabeprazole, clarithromycin and amoxicillin (RCA) was as effective as a 7-day regimen.

METHODS

A total of 139 H. pylori-infected patients were randomized to receive either a 5-day or 7-day course of rabeprazole 10 mg b.d., clarithromycin 400 mg b.d. and amoxicillin 750 mg b.d. Eradication was assessed by CLO test, histology and 13C-urea breath test.

RESULTS

On the intention-to-treat basis, eradication rates were 66% (46 out of 70) and 84% (58 out of 69) for the 5- and 7-day regimens, respectively (P < 0.05). Using per protocol analysis, eradication rates were 70% (46 out of 66) and 91% (58 out of 64) for the 5- and 7-day regimens, respectively (P < 0.01). Adverse events, which were observed in 14 patients from each group, caused discontinuation of treatment in only two patients, resulting in excellent compliance.

CONCLUSIONS

Our 5-day regimen of RCA yielded inferior results, whereas the 7-day regimen achieved an eradication rate exceeding 90% on the per protocol basis. Therefore, treatment regimens of less than 7 days for proton pump inhibitor-clarithromycin-amoxicillin therapies cannot be recommended.

A study of carboplatin-coated tube for the unresectable cholangiocarcinoma

Most cases of cholangiocarcinoma have reached an unresectable stage by the time they are discovered despite significant progress of diagnostic modalities. Many of these patients with obstructive jaundice are often treated by biliary drainage using stents to relieve the jaundice. However, the stent patency period is as short as 3 to 9 months because of tumor ingrowth or overgrowth, and mean survival is at most 12 months. Therefore, both continuous relief of obstructive jaundice and local control of the tumor are required in the treatment for advanced cholangiocarcinoma. In this investigation, we developed a new percutaneous transhepatic biliary drainage tube coated with carboplatin (carboplatin-coated tube; CCT). CCT continuously released a fixed amount of carboplatin for 4 weeks and showed an antitumor effect on human cholangiocarcinoma cell line HuCC-T1 in vitro. When CCT was embedded in subcutaneous tumor inoculated in nude mice, a significant reduction of tumor size with no apparent damage to normal adjacent tissue was observed. On the basis of these studies, 5 patients with inoperable cholangiocarcinoma were treated with CCT for 4 weeks. Overall efficacy rate of 5 patients with cholangiocarcinoma was 60% (partial response in 3 and no change in 2). No apparent side effect was observed in these patients. Thus, CCT may provide a new treatment modality for this disease. Randomized controlled trials comparing CCT therapy with palliative stenting are required to confirm these results.

Relationship between regional severity of emphysema and coronary heart disease

We analyzed the relationship between regional severity of emphysema, which was evaluated by three-dimensional fractal analysis (3D-FA) of Technegas SPECT images, and coronary heart disease (CHD). For 22 patients with emphysema who underwent Technegas SPECT, we followed up CHD events. The follow-up period was 5.4+/-0.5 (mean +/- SD) years. We defined the upper-lung fractal dimension (U-FD) and lower-lung fractal dimension (L-FD) obtained with 3D-FA of Technegas SPECT images as the regional severity of emphysema. FD became greater with the progression of emphysematous change. During the follow-up period, CHD events occurred in 6 (27%) of the 22 patients. The ratio of U-FD to L-FD for patients with CHD events (0.87+/-0.22) was significantly smaller than for patients without CHD events (1.52+/-0.38) (p = 0.0015). These findings suggest that severer emphysema in the lower lung indicates a higher risk of CHD than that in the upper lung.

Monoclonal antibody against bovine alpha1-acid glycoprotein

Monoclonal antibodies (Mabs) against bovine alpha1-acid glycoprotein (alpha1AGP) were prepared from mouse hybridoma cell line. Bovine alpha1AGP as antigen was purified by using ion exchange column chromatography and the yield from 500 ml serum was about 10 mg. Immunoglobulin isotypes of 3 Mabs obtained were IgM and light chain types were kappa. The Mabs reacted with bovine alpha1AGP on immunoblot analysis, but not with alpha1AGP digested with N-glycosidase, suggesting that an epitope recognized by these Mabs may be associated with a glycan side chain of bovine alpha1AGP.

Implication of NF-kappaB in Helicobacter pylori-associated gastritis

OBJECTIVE

Transcription factor NF-kappaB plays a pivotal role in inflammatory responses by up-regulating mRNA expression of bioactive molecules such as chemokines and adhesion molecules. The present study was designed to elucidate the implication of NF-kappaB in Helicobacter pylori-associated gastritis (HAG).

METHODS

We examined 41 patients with HAG and 18 H. pylori-negative control subjects. Expression of activated NF-kappaB was studied in situ by immunohistochemistry using alpha-p65 mouse monoclonal antibody (alpha-p65 mAb), which recognizes activated NF-kappaB. To identify the cell types in which NF-kappaB was activated, we performed immunohistochemical analysis using antibodies against vascular endothelial cells, macrophages, and B and T lymphocytes. We also examined the colocalization of activated NF-kappaB with the of intercellular expression adhesion molecule-1 (ICAM-1) on endothelial cells. We measured the levels of NF-kappaB-dependent chemokines including interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1), regulated on activation normal T-cell expressed and secreted (RANTES) and macrophage inflammatory protein-1alpha (MIP-1alpha) in antral mucosa by ELISA (ELISA).

RESULTS

Activated NF-kappaB was detected in the nuclei of epithelial cells in antral mucosa, especially of patients with HAG. NF-kappaB positivity index (NF-kappaB PI), representing the percentages of epithelial cells with positive nuclear staining for activated NF-kappaB, was significantly higher in patients with HAG than in H. pylori-negative controls. NF-kappaB PI correlated significantly with histological scores of gastritis. Moreover, activated NF-kappaB was identified in the nuclei of vascular endothelial cells, macrophages, and B lymphocytes within the lamina propria in HAG. Colocalization of activated NF-kappaB with ICAM-1 expression in the same endothelial cells was demonstrated. The IL-8 levels significantly correlated with the NF-kappaB PI.

CONCLUSIONS

In addition to epithelial cells, macrophages, vascular endothelial cells, and B lymphocytes contained activated NF-kappaB. In these cells, activated NF-kappaB may be involved in the inflammation process in HAG through the up-regulation of chemokines or adhesion molecules.

Serial changes in enzyme inhibitory antibody to pyruvate dehydrogenase complex during the course of primary biliary cirrhosis

To assess the usefulness of enzyme inhibition assay for the diagnosis of primary biliary cirrhosis (PBC), we determined the serial changes in enzymatic inhibitory antibody to pyruvate dehydrogenase complex (PDC) in patients with PBC, and compared the results to those of immunofluorescence and immunoblotting. Forty-nine sera from 19 patients with PBC who were followed-up for at least 16 months were tested for antimitochondrial antibodies (AMA) by indirect immunofluorescence, immunoblotting on bovine heart mitochondria, and enzyme inhibition assay using commercially available TRACE Enzymatic Mitochondrial Antibody (M2) Assay (EMA) kit. Of the 49 sera, 39 (80%), 35 (71%), 38 (78%), 31 (63%), and 36 (73%) were positive for AMA by immunofluorescence, for immunoglobulin G (IgG), IgM, and IgA class antibody against E2 subunit of PDC (PDC-E2) by immunoblotting, and for enzymatic inhibitory antibody to PDC by EMA, respectively. AMA titers determined by immunofluorescence did not change in 9 patients (47%), increased in 4 (21%), decreased in 3 (16%), and fluctuated in 3 (16%) during follow-up. The number of anti-M2 bands by immunoblotting did not change in 9 (47%), increased in 6 (32%), decreased in 2 (11%), and fluctuated in 2 (11%). Units of PDC activity by EMA did not change markedly in 16 (84%), increased in 2 (11%), and fluctuated in 1 (5%). Positive EMA results were common in cases with high levels of serum alkaline phosphatase and IgM, and the units of PDC activity by EMA correlated significantly and inversely with AMA titers by immunofluorescence, and serum reactivity to PDC-E2 by immunoblotting, respectively. There was no correlation between serial changes in biochemical data and units of PDC activity by EMA. In three patients who showed a decrease in AMA titers, AMA titers correlated more with EMA results than immunoblotting. Moreover, in a patient with fluctuating AMA titers, the units of PDC activity by EMA paralleled AMA titers. Our results suggest that EMA is useful for the diagnosis of AMA-positive PBC, and also could be used for monitoring the disease course in PBC.

The changes in glycosylation after partial hepatectomy enhance collagen binding of vitronectin in plasma

Vitronectin is a multifunctional glycoprotein present in the extracellular matrix and plasma. Changes in rat vitronectin were studied during liver regeneration after partial hepatectomy. Carbohydrate concentrations of vitronectin decreased to 2/3 of sham-operated rats at 24 h after partial hepatectomy. Carbohydrate composition and lectin reactivity indicated that N-glycosylation and sialylation of vitronectin changed markedly after partial hepatectomy, while amino acid composition did not change significantly. We previously showed that deN-glycosylation of vitronectin in vitro affects collagen binding among various ligands (Yoneda et al., Biochemistry (1998) 37, 6351-6360). Vitronectins from partially hepatectomized rats at 24 h were found to exhibit markedly enhanced binding to type I collagen. The effect of sialylation on collagen binding was further examined using enzymatically deglycosylated vitronectin of nonoperated rats. Collagen binding increased by 1.2 times after deN-glycosylation of vitronectin, while it increased more than 2.9 times after desialylation. Various glycosyltransferases in liver are known to change after partial hepatectomy, including the attenuation of N-oligosaccharide transferase. The findings therefore suggest that the collagen binding of vitronectin is modulated by the alteration of peptide glycosylation caused by postoperative physiological changes of glycosyltransferases and that the change may contribute to tissue remodeling processes.

Extracellular ATP-dependent activation of plasma membrane Ca(2+) pump in HEK-293 cells

1. It is well known that extracellular ATP (ATP(o)) elevates the intracellular Ca(2+) concentration ([Ca(2+)](i)) by inducing Ca(2+) influx or mobilizing Ca(2+) from internal stores via activation of purinoceptors in the plasma membrane. This study shows that ATP(o) also activates the plasma membrane Ca(2+) pumps (PMCPs) to bring the elevated [Ca(2+)](i) back to the resting level in human embryonic kidney-293 (HEK-293) cells. 2. The duration of ATP(o)-induced intracellular Ca(2+) transients was significantly increased by PMCP blockers, La(3+) or orthovanadate. In contrast, replacement of extracellular Na(+) with NMDG(+), a membrane-impermeable cation, had no significant effect on duration, thus suggesting that Na(+)/Ca(2+) exchangers do not participate in the ATP(o)-induced Ca(2+) transient. 3. A rapid and significant decrease in [Ca(2+)](i), which was not dependent on extracellular Na(+), was induced by ATP(o) in cells pretreated with thapsigargin (TG). This decrease was blocked by orthovanadate, indicating that it was caused by PMCPs rather than sarco/endoplasmic reticulum Ca(2+) pumps (SERCPs). 4. UTP and ATPgammaS also caused a decrease in [Ca(2+)](i) in cells pretreated with TG, although they were less effective than ATP. The effect of UTP implies the involvement of both P2Y(1) and P2Y(2) receptors, while the effect of ATPgammaS implies no significant role of ectophosphorylation and agonist hydrolysis in the agonist-induced [Ca(2+)](i) decreases. 5. These results point to a role of PMCPs in shaping the Ca(2+) signal and in restoring the resting [Ca(2+)](i) level to maintain intracellular Ca(2+) homeostasis after agonist stimulation.

Melatonin scavenges hydroxyl radical and protects isolated rat hearts from ischemic reperfusion injury

During postischemic reperfusion, free radicals are produced and have deleterious effects in isolated rat hearts. We investigated whether melatonin (MEL) reduces the production of hydroxyl radical (*OH) in the effluent and aids in recovery of left ventricular (LV) function. Hearts were subjected to 30 min of ischemia followed by 30 min of reperfusion. Salicylic acid (SAL) was used as the probe for *OH, and its derivatives 2,5- and 2,3-dihydroxybenzoic acid (DHBA) were quantified using HPLC. In addition, thiobarbituric acid reactive substances (TBARS) in the myocardium was measured. Plateaus in the measurement of 2,5- and 2,3-DHBA were seen from 3 to 8 min after reperfusion in each group. The group that received 100 microM MEL+ SAL had significantly reduced amounts of 2,5- and 2,3-DHBA by multiple folds, compared to the SAL group. TBARS was significantly decreased in the 100 microM MEL group (1.20+/-0.36 vs 1.85+/-0.10 micromol/g of drug-free group, p<0.001). More importantly, the 100 microM MEL group significantly recovered in LV function (LV developed pressure, +dp/dt, and -dp/dt; 63.0%, 60.3%, and 59.4% in the 100 microM MEL group; 30.2%, 29.7%, and 31.5% in the drug-free group, respectively; p<0.05). Duration of ventricular tachycardia or ventricular fibrillation significantly decreased in the 100 microM MEL group (100 microM MEL, 159+/-67 sec; drug-free, 1244+/-233 sec; p<0.05). As a result of scavenging *OH and reducing the extent of lipid peroxidation, MEL is an effective agent for protection against postischemic reperfusion injury.

Impact load transmission of the knee joint-influence of leg alignment and the role of meniscus and articular cartilage

OBJECTIVE

The objective of this study was to evaluate load transmission in the cancellous bone of the tibia under static and impact load.BACKGROUND. Abnormal transmission of loads may result in osteoarthritis and fractures. However, the role of the cancellous bone in these processes is not well understood.METHODS. The compressive stresses in the subchondral bone, epiphysis and diaphysis of the tibia of porcine knees were measured under static and impact load using mini-pressure transducers. The tests were performed using a drop-tower type testing machine in neutral, varus and valgus alignments. Tests were repeated after meniscectomy and again after removing the articular cartilage.RESULTS. In the intact knee in all alignments, the highest stress on the medial side was found in the epiphysis, and in the subchondral bone on the lateral side. After meniscectomy, a significant increase was observed in the stress in the subchondral bone on both sides. After the articular cartilage was also removed, the stress in the subchondral bone increased again, but slightly.CONCLUSION. The importance of the meniscus in load transmission is supported by this study. The contribution of the articular cartilage to load transmission is less than that of the meniscus.Relevance. The patterns of static and dynamic load transmission observed in this study correlate with the sites of insufficiency fractures of the medial tibial plateau and traumatic lateral tibial plateau fractures observed clinically. Examination of the load transmission is key to a more complete understanding of the causes of osteoarthritis and tibial plateau fractures.

Simultaneous intravascular two-dimensional plus Doppler ultrasound is useful for evaluation of postischemic vasodilatation: plasm NOx - levels determined by the Griess method may not reflect the extent of postischemic NO-induced vasodilatation

Our objective was 1) to assess postischemic vasodilatation using simultaneous intravascular two-dimensional and Doppler ultrasound, and 2) to clarify whether plasma nitrite and nitrate (NOx-) levels change during postischemic vasodilatation. The vascular cross-sectional area (CSA) was evaluated in 18 mongrel dogs, and the average instantaneous peak velocity (APV) in the iliac arteries after the 5-min occlusion of blood flow was determined. Plasma NOx- levels were measured at the baseline, during the occlusion of blood flow, and 1.5, 3, and 10 min after recanalization. The %CSA significantly increased from 30 s to 7 min after the recanalization, and maximal vasodilatation was observed at 1.5 min after the recanalization (14.1 +/- 0.9 to 15.8 +/- 1.0 mm2, p< 0.0001 vs. baseline). Plasma NOx- levels were significantly reduced during the occlusion of blood flow and remained reduced at 1.5, 3, and 10 min after recanalization compared with the baseline values. We concluded that simultaneous intravascular two-dimensional and Doppler ultrasound is useful for assessment during postischemic vasodilatation, and that plasma NOx- levels assayed with the Griess reagent do not significantly increase, even when maximal vasodilatation is observed.