[Efficacy of hemostatic puncture closing device for hemostasis and early ambulation after coronary angiography and angioplasty: results of a multicenter trial]

To assess the efficacy and safety of a hemostatic puncture closing device for reducing patient immobilization after cardiac catheterization from a percutaneous femoral artery approach, we conducted a prospective, randomized trial at 4 participating centers. A total of 240 patients (183 men, 57 women, mean age 61 +/- 10 yr; 157 patients underwent diagnostic angiography, 83 patients underwent coronary angioplasty) were randomized to either the device group (n = 120) or the manual compression group (n = 120). There were no statistical differences in age, gender, weight or sheath size between the 2 groups. A 7, 8F sheath was used in 53 patients of the device group and in 43 patients of the manual compression group. One hundred and two patients (85%) in the device group and 96 patients (80%) in the manual compression group received heparin. Protamine was used in one patient of the device group and 23 patients of the manual compression group. Activated clotting time just prior to sheath removal was 206 +/- 64 sec in the device group and 170 +/- 47 sec in the manual compression group (p < 0.01). Successful placement of the device was achieved in 118 of 120 patients (98%). Time to hemostasis was significantly shorter in the device group (0.8 +/- 3.2 vs 12.2 +/- 5.3 min, p < 0.01). Time to ambulation could be reduced in the device group (5.3 +/- 3.7 vs 10.9 +/- 5.1 hr, p < 0.01). The following complication rates occurred in the device group as compared with the manual compression group: hematoma, 16% vs 10%; bleeding, 8% vs 3%; pseudoaneurysm, 0% vs 1%, respectively. None of these differences was statistically significant. These results indicate that early ambulation using a hemostatic puncture closing device is feasible without significantly increasing the risk of peripheral vascular complications.

New ether-à-go-go K(+) channel family members localized in human telencephalon

A cDNA encoding a novel voltage-gated K(+) channel protein was isolated from human brain. This protein, termed BEC1, is 46% identical to rat elk in the ether-à-go-go K(+) channel family. The BEC1 gene maps to the 12q13 region of the human genome. Northern blot analysis indicates that BEC1 is exclusively expressed in human brain, where the expression is concentrated in the telencephalic areas such as the cerebral cortex, amygdala, hippocampus, and striatum. By in situ hybridization, BEC1 is detected in the CA1-CA3 pyramidal cell layers and the dentate gyrus granule cell layers of the hippocampus. Specific signals are also found in neocortical neurons. Transfection of mammalian L929 and Chinese hamster ovary cells with BEC1 cDNA induces a voltage-gated outward current with a fast inactivation component. This current is insensitive to tetraethylammonium and quinidine. Additionally, a second related gene BEC2 was isolated from human brain. BEC2 is also brain-specific, located in the neocortex and the striatum, and functional as a channel gene. Phylogenetic analysis indicates that BEC1 and BEC2 constitute a subfamily, together with elk, in the ether-à-go-go family. The two genes may be involved in cellular excitability of restricted neurons in the human central nervous system.

Clinicopathological features and outcome of hepatic resection for intrahepatic cholangiocarcinoma in Japan

As a result of an increasing number of studies on the surgical treatment of intrahepatic cholangiocarcinoma (ICC), knowledge of its biological characteristics has been accumulating. We analyzed the clinicopathological features and outcome of 36 of 48 surgical patients with histologically proven ICC (75.0%) who underwent hepatic resection between March 1979 and July 1998. According to tumor location, 12 patients had the central type and 24, the peripheral type. The incidence of portal vein tumor thrombus and lymph node metastasis was higher in the central type than in the peripheral type. All 12 patients with the central type had stage IV disease, and none of them underwent complete resection, whereas 12 of the 24 patients with peripheral type tumors had stage IV disease; complete resection was achieved in 12 of the 24 patients with peripheral type tumors (50%). Outcome after resection was significantly poorer in the patients with the central type. The macroscopic type of lesion in the resected specimens was the mass-forming type in 15 patients (41.7%), the mass-forming + periductal-infiltrating type in 15 patients (41.7%), the periductal-infiltrating type in 3 patients (8.3%) and the intraductal growth type in 3 patients (8.3%). The macroscopic tumor type was associated with mode of tumor spread and outcome. All 3 patients with the intraductal growth type are alive without tumor recurrence 26-138 months after surgery. The survival rate was much higher in the patients with the mass-forming type than in those with the mass-forming + periductal-infiltrating type. Importantly, the outcome in the 17 patients who underwent resection for stage IV-B disease and who accounted for 47.2% of patients with resection in the present series was very poor, almost the same as that in the 12 patients who did not undergo resection. By selecting patients based on the biological characteristics of the tumor and taking into account patients' quality of life, complete surgical resection can be performed safely and is associated with long-term survival.

S4a + S5 with caudate lobe (S1) resection using the Taj Mahal liver parenchymal resection for carcinoma of the biliary tract

Recently we have been performing S4a + S5 with total resection of the caudate lobe (S1) by using a dome-like dissection along the root of the middle hepatic vein at the pinnacle, which we refer to as the Taj Mahal liver parenchymal resection, for carcinoma of the biliary tract. This procedure offers the following advantages: (1) It allows total resection of the caudate lobe, including the paracaval portion (S9), and (2) because the cut surface of the liver is large, it allows intrahepatic jejunostomy to be performed more easily with a good field of view. The indications for this procedure include hilar bile duct carcinoma, gallbladder carcinoma, and choledochal cyst (type IVA). Because of the high rate of hilar liver parenchyma and caudate lobe invasion associated with hilar bile duct carcinoma, the liver must be resected. The Taj Mahal procedure is indicated in cases where extended liver resection is impossible. The dissection limits of this procedure are, on the left side, the B2+3 bifurcation at the right margin of the umbilical portion of the portal vein and, on the right side, the B8 of the anterior branch and the B6+7 bifurcation of the right posterior branch. This procedure could also be described as a reduced form of extended right hepatectomy and extended left hepatectomy. For gallbladder carcinoma, this procedure is indicated to ensure an adequate surgical margin and eradicate transvenous liver metastasis, particularly in cases of pT2 lesions. Hilar and caudate lobe invasion also occurs in liver bed-type gallbladder carcinoma, and bile duct resection and caudate lobe resection are required for the surgery to be curative. We performed this procedure in four cases of hilar bile duct carcinoma, five cases of gallbladder carcinoma, and one case each of choledochal cyst (type IVA) with carcinoma of the bile duct and gallbladder adenomyomatosis. Curative resection was possible in all except the patient with adenomyomatosis, and all of the patients are alive and recurrence free 10 to 37 months postoperatively. This procedure, in addition to preserving liver function, provides a wide field of view and facilitates reconstruction of multiple intrahepatic bile ducts. Thus it can be said to be a curative operation not only in patients considered high risk but also in those whose hilar bile duct carcinoma is limited to the bifurcation area (Bismuth type IIIa and IIIb) and in gallbladder carcinoma up to pT2 with slight extension on the hepatic side.

Rapid and sensitive vasopressin heteronuclear RNA responses to changes in plasma osmolality

The plasma concentration of arginine vasopressin (AVP) is closely regulated by plasma osmolality. In this study, we used intronic in-situ hybridization to investigate the transcriptional activity of the AVP gene in the supraoptic nucleus (SON) and paraventricular nucleus (PVN) after intraperitoneal (i.p.) injection of hypertonic saline inducing small changes in plasma osmolality in rats. After ip injection of 900 mOsm/kg saline (2% BW), plasma [Na] reached the highest level at 10 min (900 mOsm/kg, 146+/-1 mEq/l; 290 mOsm/kg, 139+/-1 mEq/l, P<0.01) and maintained that level until 30 min. The expression of AVP heteronuclear (hn) RNA in the SON and PVN increased significantly as early as 10 min and peaked 30 min after ip injection of the hypertonic saline. AVP hnRNA expression showed a significant increase even after a 2 mEq/L elevation in plasma [Na] concentration, and increased dose-dependently in response to the concentration of saline injection (290-900 mOsm/kg). These results demonstrate that, similar to AVP secretion, AVP gene transcriptional activity in the SON and PVN is closely regulated by plasma osmolality.

[Correlation of risk area and reverse redistribution of 99mTc-sestamibi SPECT in acute myocardial infarction following direct PTCA]

Redistribution of 99mTc-sestamibi is negligible in usual circumstances, but recent reports demonstrated reverse redistribution is detectable in acute myocardial patients. Correlation of risk area, observed in 99mTc-sestamibi "freezed" SPECT image at onset, and delayed images at 5-25 days after onset (post-PTCA image) is evaluated in 19 acute myocardial infarction patients treated with direct PTCA. Reverse redistribution was observed in 85% of reperfused area. Linear relationship of % uptake in each SPECT segment between onset and post-PTCA images (taken at 0.5, 4, and 6 hours after injection) is evaluated and the relationship improves over time course. The correlation coefficient between onset and 6 hours-delayed image is 0.88, and the visual concordance shows 77% of score matching. Delayed 99mTc-sestamibi SPECT image on reperfused AMI seems to represent risk area with some underestimation. It may be useful to estimate both risk and salvaged areas on early and delayed SPECT with a single 99mTc-sestamibi injection.

Thrombectomy with AngioJet catheter in native coronary arteries for patients with acute or recent myocardial infarction

The AngioJet thrombectomy catheter removes thrombi by rheolytic fragmentation and suction. The purpose of this study was to identify the efficacy and safety of this new device. Myocardial infarction (MI) is associated with intracoronary thrombus. Intracoronary thrombus has been identified as a risk factor of unfavorable outcome after percutaneous transluminal coronary angioplasty. To what extent the AngioJet is applicable or effective for acute or recent MI in native coronary artery is not clear. Thrombectomy with the AngioJet was attempted in 31 patients with 31 native coronary arteries selected from 304 patients with acute or recent MI. Follow-up angiography was performed at 3 to 6 months. Procedure success was achieved in 29 patients (94%). Adjunctive balloon angioplasty was performed after AngioJet thrombectomy in 30 patients (97%), and in only 1 patient (3%) AngioJet thrombectomy was the sole procedure. Subsequent stenting after balloon angioplasty was attempted successfully in 12 patients (40%) without thrombotic complications. Thrombolysis In Myocardial Infarction trial flow grading increased from 0.70 +/- 0.97 before to 2.61 +/- 0.88 after AngioJet thrombectomy (p <0.0001), to 2.84 +/- 0.64 after adjunctive procedures (p = 0.070). At follow-up angiography restenosis rate was 21% but Thrombolysis In Myocardial Infarction flow 3 was present in all patients. The restenosis rate of stented patients was 8%. There were no major events during in-hospital and follow-up. The AngioJet can be used safely and successfully to remove thrombus from the native coronary artery of patients with MI. Thrombus removal makes subsequent stenting safe and uncomplicated. The restenosis rate was considered to be acceptable.

Human antibody isotype responses to Schistosoma japonicum egg antigen

Schistosoma japonicum-infected subjects from Hubei province of China were investigated to determine the class and subclass of the antibody response to soluble egg antigen (SEA), using an enzyme-linked immunosorbent assay. The subjects were 50 acute and 55 chronic cases. In acute cases, the mean OD values for IgA, IgE and IgG3 were very high, while the positive ratios of IgA and IgE were only 78% and 74%, respectively. The positive ratios of IgG, IgM, IgG1, IgG3 and IgG4 were all above 90%. In chronic cases, the mean OD values for IgG, IgG3 and IgG4 were very high, and the positivity rates of IgG, IgG1, IgG3 and IgG4 were all above 90%. Comparing the two study groups, the mean OD values of IgM, IgA, IgE were higher in acute cases than those of chronic cases (p < 0.0001), while the mean OD values of IgG, IgG4 were higher in chronic cases than in acute cases (p < 0.05). The mean OD values of IgG3 in both groups were high and those of IgG2 in both groups were low.

[The role and expression of CD27/CD70 in tonsil]

We studied the expression and function of CD27 and CD70, which are reported to play an important role in the T-B cell interaction in tonsillar lymphocytes of patients with chronic tonsillitis. In comparison of CD27 and CD70 in peripheral lymphocytes of each patients, no significant difference was found. Furthermore, CD27 and CD70 in T-B cell interaction and antibody production in the tonsil was studied. Our findings was confirmed that CD27 and CD70 are involved in interactions between T/T, T/B and B/B cells. A comparative study of CD27- CD4+ cells and CD70+ CD4 cells, so-called memory cells in the T cell subset, was made in tonsillar lymphocytes and peripheral lymphocytes. No significant difference was found in the presence of CD27+ CD4+ cells, but the CD27- CD4+ cells increased in tonsillar lymphocytes. This suggests recurrent antigenic stimulation and the presence of memory cells in tonsillar lymphocytes. Localization of CD27 and CD70 in tonsillar tissue was also investigate.

[Elevated levels of plasma homocysteine related to saphenous vein graft disease after coronary artery bypass graft surgery]

Elevated levels of plasma homocysteine may be an independent risk factor for coronary atherosclerosis. This study investigated whether plasma homocysteine levels are related to atherosclerotic lesions of saphenous vein grafts after coronary artery bypass surgery. Homocysteine levels were measured in fasting plasma by high-performance liquid chromatography and total cholesterol, triglyceride, high density lipoprotein cholesterol and lipoprotein (a) were also evaluated in 40 patients (mean age 65 +/- 8 years, mean interval after bypass surgery: 6.1 +/- 3.1 years, range 1-13 years). The vein graft disease group was defined as patients with angiographical stenosis of > or = 50% in any vein graft (n = 23). The other patients were defined as the no-vein graft disease group (n = 17). Patients who had a history of chronic renal failure or anatomic lesions of saphenous vein grafts were excluded. The distributions of homocysteine were skewed. Median homocysteine levels were 11.9 nmol/ml in all subjects. Homocysteine levels in the vein graft disease group were significantly higher than in the no-vein graft disease group (median 15.1 vs 10.6 nmol/ml, p = 0.01). In the analysis of plasma lipids, high-density lipoprotein cholesterol levels were significantly lower in the vein graft disease group than in the no-vein graft disease group (mean 37 +/- 11 vs 48 +/- 13 mg/dl, p = 0.01). Multiple regression analysis showed that elevated levels of homocysteine were an independent risk factor for saphenous vein graft disease after coronary artery bypass surgery. These findings indicate that elevated levels of plasma homocysteine are related to atherosclerotic lesions of saphenous vein grafts after coronary artery bypass surgery as well as coronary atherosclerosis.

A case of inflammatory pseudotumor of the liver causing elevated serum CA19-9 levels

Inflammatory pseudotumor of the liver is a rare lesion characterized by proliferating fibrovascular tissue admixed with inflammatory cells. A 50-yr-old Japanese man was hospitalized because of upper abdominal pain and high fever. Computed tomography revealed a poorly demarcated, low density mass in the left lobe of the liver, and abnormal laboratory findings included WBC 9340/mm3, CRP 10.5 mg/dl, and marked elevation of CA19-9 to 1167.9 U/ml. Endoscopic retrograde cholangiography showed irregularity of the intrahepatic bile duct of the left lateral segment, and the lateral segmental branches of the portal vein were not visualized on the venous phase of abdominal angiography. Ultrasound-guided liver biopsy was performed, but malignant disease, including intrahepatic cholangiocarcinoma, could not be completely ruled out. The patient underwent left hepatic lobectomy with lymph node dissection. Histopathological examination yielded a definitive diagnosis of inflammatory pseudotumor. The lesion was immunohistochemically stained for CA19-9 by the ABC method, and the biliary epithelium in severely inflamed portal canals was found to be positive. The markedly elevated preoperative level of CA 19-9 decreased to almost within the normal range and the patient remains well 2 yr 9 months after surgery, without any complications.

Initial and follow-up results of the ACS multi-link stent: a single center experience

The Palmaz-Schatz (PS) stent has effectively reduced restenosis; however its rigidity makes it sometimes difficult or impossible to deliver. The initial and follow-up outcomes with the ACS Multi-Link stent (deployed from April to November 1995) were evaluated in 70 patients (79 lesions): unplanned in 34% (abrupt closure 1%; threatened closure 5%; suboptimal results 28%) and planned in 66%. Three to six month follow-up angiograms were analyzable in 67 lesions; 96% procedural (in nine lesions PS stenting had failed) and 95% clinical success were achieved. In-hospital mortality was 1.4%. Myocardial infarction occurred in 2.9%, and subacute stent thrombosis in 1.4%. Stenting improved immediately the minimal luminal diameter (from 0.97+/-0.41 mm to 2.72+/-0.31 mm), but at 6 months it had decreased to 1.89+/-0.44 mm. Angiographic restenosis (<50% diameter stenosis) occurred in 11, a rate of 16.4%; target lesion revascularization (TLR) was required in six (re-PTCA in five or bypass surgery in one; 6/67=8.7%). Actuarial 1-2 year survival rate was 91%, 80% surviving free from major complications or need for TLR. We conclude that the ACS Multi-Link stent can be implanted in lesions unsuited for the PS stent with a high success rate, and an anticipated restenosis rate perhaps comparable to with the PS stent.

[PTCA for acute coronary syndrome]

The use of intravenous thrombolytic therapy have revolutionized the medical management of acute MI, prolonging survival and preserving LV function. Yet, despite these important beneficial effects, many deficiencies exist, such as the fewer lytic eligible patients, the low rate of complete reperfusion and high incidence of recurrent Ischemia and intracranial hemorrhage. To improve on these deficiencies, several PTCA strategies for acute MI have emerged, including primary PTCA, rescue PTCA, immediate PTCA, and delayed PTCA. If skilled intervention-list and cath lab team are available, the optimal reperfusion strategy is primary PTCA. If a cath lab is not available and the patient is eligible for thrombolysis, intravenous thrombolytic therapy should be administered. Nevertheless, PTCA still has significant limitations, including complex lesion morphology and restenosis. Preliminary experience support the feasibility and safety of coronary stenting in the setting of acute MI. A randomized trial using the heparin-coated Palmaz-Schatz stent for primary stenting in MI is ongoing. Until a randomized trial data are available, we recommend stenting for provisional stenting.

[A case of spontaneous hemopneumothorax occurred after thoracic drainage]

A 21-year-old man; complaining of left chest pain and dyspnea, was admitted to our hospital with a diagnosis of spontaneous pneumothorax. Though chest X-ray on admission did not show hemothorax, chest drainage revealed intrapleural bleeding. As chest X-ray on the following day showed evident fluid level, emergency operation was carried out with a diagnosis of spontaneous hemopneumothorax. Bleeding point was a ruptured vessel between parietal pleura and bulla in apex of lung. The bulla was resected following hemostasis. After improvement of complicating postoperative re-expansive pulmonary edema, the patient was discharged on the 18th postoperative day. On treatment of spontaneous hemopneumothorax, existence of such a case as ours should be taken into account.

Steroid 5alpha-reductase type 1 immunolocalized in the rat peripheral nervous system and paraganglia

Steroid 5alpha-reductase is an enzyme that converts a number of steroids with a C-4, 5 double bond and C-3 ketone to 5alpha-reduced metabolites. This enzyme has been suggested to play a role in brain development and myelination in the rat nervous system. In the present study, we examined the cellular and subcellular localization of the enzyme immunocytochemically in the rat peripheral nervous system and paraganglia using a polyclonal antibody against rat 5alpha-reductase type 1. Light and electron microscopical studies localized 5alpha-reductase in the Schwann cells of myelinated and unmyelinated nerve fibres, the satellite cells of the ganglia, the enteric glial cells and the supporting/sustentacular cells of the paraganglia. In the myelinated nerve fibres, immunoreactivity was observed in the outer loops, the nodes of Ranvier and the Schmidt-Lanterman incisures. Subcellularly, the immunoreactivity was localized in the cytoplasm of various glial cells. No immunoreactivity was observed in the myelin membrane, the axon or the neuronal perikaryon. These findings suggest that 5alpha-reductase is widely distributed in glial cells, and that, in addition to myelination, 5alpha-reduced steroids play a role in some glial functions in the peripheral nervous system.

Correlation analysis between fatty acid compositions of zooplankter individuals, fed on different phytoplankton species by means of pyrolysis-gas chromatography combined with on-line methylation

Pyrolysis-gas chromatography (Py-GC) combined with on-line methylation was applied to a correlation analysis between the distributions of fatty acid components in the lipids of zooplankter individuals and those of ingested algae using principal component analysis (PCA). Py-GC in the presence of organic alkali, tetramethylammonium hydroxide (TMAH), was used to estimate the apparent distributions of fatty acid components contained in a single individual zooplankter weighing several tens of micrograms and a small sample size of ingested algae samples in the order of 10 microg. The observed fatty acid compositions were used as a database for the PCA in order to discriminate the zooplankton and ingested algae samples. The result obtained indicated that the fatty acid compositions of zooplankton individuals used in this work were significantly reflected in those of their ingested food in spite of some contribution from isomerization and/or elongation of fatty acid components during digestion of the ingested algae phytoplankton in living zooplankters.

The effects of a thromboxane A2 synthesis inhibitor and a prostaglandin I2 analogue on experimental acute necrotizing pancreatitis in rats

To elucidate the role of thromboxane A2 (TxA2) and prostaglandin I2 (PGI2) in acute necrotizing pancreatitis (ANP) in rats and to determine the effect of the TxA2 synthesis inhibitor OKY-046 and the PGI2 analogue OP-2507, the levels of two prostanoids (TxB2, 6-keto PGF1alpha) and two types of phospholipase A2 (PLA2) activity (cytosolic and secretory) were measured in plasma and three tissues (pancreas, lung, and kidney) after injection of a mixed solution of 5% sodium taurocholate and 0.1% trypsin into the pancreatic duct to induce ANP. The survival rate 24 h after inducing ANP was 33.3% in the nontreated group, versus 83.3 and 58.3% in the groups treated with OKY-046 and OP-2507, respectively. Only the group treated with OKY-046 showed significant improvement compared with the nontreated group. The plasma, pancreatic, and pulmonary TxB2 levels decreased significantly in the group treated with OKY-046, and the histopathological changes were not as severe. The levels of pancreatic and pulmonary cytosolic PLA2 activities decreased, and plasma and pancreatic secretory PLA2 activities also decreased. In conclusion, the levels of both types of PLA2 activity and TxA2 production decreased, and the survival rate improved as a result in the group treated with OKY-046, but OP-2507 had no effect on ANP. TxA2 and two types of PLA2 activity play an important role in the process of aggravation of acute pancreatitis.

Vectorcardiographic evaluation of myocardial infarct size: departure parameters are superior to conventional spatial parameters

To determine whether the departure parameters derived from a "departure loop" of a vectorcardiogram are more accurate than conventional spatial parameters in evaluating myocardial infarct size, 74 patients with first-onset myocardial infarction (MI) were studied. The correlation between the departure parameters (amplitudes in scalar leads of the departure loop) and the percent defect volume of thallium myocardial scintigrams (%DV) was compared with that of the spatial parameters (magnitude, azimuth, and elevation of the original QRS loop). In anteroseptal MI, the amplitude of a 20-msec vector in the z-axis and the azimuth of a 30-msec vector (H30) were significantly correlated with %DV (r=0.783, p<0.001 and r=0.572, p<0.05). In anteroseptal MI with involvement of the lateral wall, the amplitude of a 30-msec vector in the x-axis and H30 showed significant correlation with %DV (r=0.802, p<0.001 and r=0.772, p<0.01). In inferior and inferoposterior MI, the amplitude of a 30-msec vector in the y-axis and the elevation of a 30-msec vector were significantly correlated with %DV (r=0.920, 0.891, p<0.001 and r=0.871, 0.678, p<0.01, respectively). In conclusion, the departure parameters are more accurate than the spatial parameters for evaluation of myocardial infarct size.

Sonochemical polymerization of benzene derivatives: the site of the reaction

Sonochemical polymerization of benzene and halogen-substituted benzenes has been studied. The difference of absorption spectra of polymerization products can be explained qualitatively using bond energies of the primary products. The relative rate constant of the polymerization reaction is apparently proportional to the inverse of the vapour pressure of the liquids. Using this relation, we analysed the relative rate constant of the polymerization in benzene/chrolobenzene mixtures. From this, we conclude that sonochemical polymerization proceeds in the vapour phase of a bubble.

Central administration of urocortin inhibits vasopressin release in conscious rats

Urocortin (UCN) is a new mammalian member of the corticotropin releasing factor (CRF) family and supposed to be an endogenous ligand for type 2 CRF receptors. Previous studies have revealed that UCN mRNA exists in the supraoptic nucleus (SON), and that water deprivation increases UCN immunoreactivity in SON. In this study, we examined the effect of centrally-administered UCN on arginine vasopressin (AVP) release in conscious rats. Intracerebroventricular (i.c.v.) injection of UCN (5.0 microg/rat) significantly attenuated AVP release induced by hyperosmolality at 30 min after the injection. In contrast, CRF (5.0 microg/rat) injected i.c.v. had no significant effect on AVP release. These results suggest that central UCN play an inhibitory role in osmoregulation of AVP release.

Regulation of vasopressin synthesis and release by area postrema in rats

There is evidence indicating that the area postrema (AP), the most caudal circumventricular organ located on the dorsal surface of the medulla, is involved in several physiological regulations. In this study, we investigated the role of AP in the regulation of arginine vasopressin (AVP) synthesis and release, using rats of which the AP was lesioned 6 weeks previously. The level of plasma AVP in the AP lesioned (APX) group was significantly lower than in the sham operated (Sham) group in the basal state. AVP release induced by either hyperosmolality or hypovolemia was significantly attenuated by APX. To clarify the role of AP in AVP synthesis in the hypothalamus, we examined the AVP gene expression using in situ hybridization. AVP messenger RNA levels in paraventricular (PVN) and supraoptic nuclei (SON) in the APX group were significantly lower than in the Sham group in the basal state. Moreover, the AVP messenger RNA levels in PVN and SON in the APX group were also significantly lower than in the Sham group after water deprivation for 3 days. These results suggest that AVP synthesis and release are tonically stimulated by AP in the basal state and that AVP synthesis and release in stimulated states are also regulated, at least partially, by AP.

Age-associated decrease in response of rat aquaporin-2 gene expression to dehydration

It is well known that urine-concentrating ability decreases with aging and that this decreasing ability results from a reduced sensitivity of the renal collecting duct to arginine vasopressin (AVP). AVP regulates the water channel (aquaporin-2:AQP2) through V2 receptors and increases the water permeability of the collecting duct. To elucidate the mechanism of change with aging in urine-concentrating ability, we investigated the change of V2 receptor and AQP2 mRNA expression in young (8-week-old) and older (7-month-old) rats after dehydration for 2 days. After dehydration, plasma AVP levels in older rats were higher than young rats, and urinary osmolality in older rats was lower than young rats. By Northern blot analysis, there was no significant difference between young and older rats in both V2 receptor and AQP2 mRNA expression before dehydration. After dehydration, V2 receptor mRNA expression in young and older rats decreased in the same degree, suggesting the downregulation of V2 receptors may occur in the mRNA level. Northern blot analysis and in situ hybridization histochemistry showed that AQP2 mRNA expression increased and the increased expression in older rats was less than in young rats. The present study suggests the reduced response of AQP2 mRNA expression to dehydration, observed in 7-month-old rats, might be partially responsible for the decreasing urine-concentrating ability with aging.

Possible new route for the production of C60 by ultrasound

The production of C60 by ultrasonic irradiation of liquid benzene has been studied. After irradiating 150 ml of liquid benzene for 1 h (600 W, 20 kHz), approximately 1 microgram of C60 is produced.