Endothelium-dependent relaxations are achieved by a combination of endothelium-derived prostacyclin (PGI2), nitric oxide (NO), and endothelium-derived hyperpolarizing factor (EDHF). However, it remains to be fully clarified whether the relative contribution of these three mechanisms to endothelium-dependent relaxations varies as a function of the vessel size. This study was designed to clarify this point. Acetylcholine (ACh)-induced endothelium-dependent relaxations were examined in isolated blood vessels taken from the aorta and the proximal and distal mesenteric arteries of the rat. The contributions of PGI2, NO, and EDHF were evaluated by the inhibitory effects of indomethacin, N omega-nitro-L-arginine methyl ester (L-NAME) in the presence of indomethacin, and KCl in the presence of indomethacin and L-NAME, respectively. The membrane potentials were recorded with microelectrodes. The expression of endothelial No synthase (eNOS) was examined by both immunostaining and immunoblotting. The contribution of PGI2 was negligible in three different-sized blood vessels. The contribution of NO was most prominent in the aorta, whereas that of EDHF was most prominent in the distal mesenteric arteries. The resting membrane potential was significantly deeper and the ACh-induced hyperpolarization was greater in the distal mesenteric arteries than those in the aorta. The expression of eNOS was the highest in the aorta and the lowest in the distal mesenteric arteries. These results indicate that the importance of EDHF increases as the vessel size decreases in endothelium-dependent relaxations in the rat mesenteric circulation.

Background and Purpose-We estimated the incidence of first-ever cerebral infarction in regard to its subtypes and analyzed their risk factors separately in a community-based prospective cohort study in Japan. Methods-Stroke-free subjects (nϭ1621) aged Ն40 years were followed up for 32 years from 1961. During this period, 298 cerebral infarctions occurred and were divided into 167 lacunar, 62 atherothrombotic, 56 cardioembolic, and 13 undetermined subtypes of infarction on the basis of clinical information including brain imaging and autopsy findings. Results-The age-adjusted incidence of lacunar infarction (3.8 per 1000 person-years for men and 2.0 for women) was higher than that of atherothrombotic infarction (1.2, 0.7) and cardioembolic infarction (1.3, 0.5) in both sexes. Time-dependent Cox's proportional hazard analysis revealed systolic blood pressure as well as age to be independent risk factors for all subtypes of cerebral infarction except for cardioembolic infarction in men. Additionally, ST depression on ECG, glucose intolerance, and smoking in men and left ventricular hypertrophy on ECG and body mass index in women remained significant risk factors for lacunar infarction. ST depression was also significantly related to events of atherothrombotic infarction in women. The risk of atrial fibrillation for cardioembolic infarction was outstandingly high in both sexes, and left ventricular hypertrophy and lower total cholesterol were additional risk factors for cardioembolic infarction in women. Conclusions-In this Japanese population, lacunar infarction was the most common subtype of cerebral infarction and had a greater variety of risk factors, including not only hypertension but also ECG abnormalities, diabetes, obesity, and smoking, than did atherothrombotic infarction or cardioembolic infarction. (Stroke. 2000;31:2616-2622.)

The endothelium-dependent vascular relaxation to acetylcholine (ACh) in spontaneously hypertensive rats (SHR) may be impaired because of an imbalance of endothelium-derived relaxing factor and contracting factor. However, the role of the endothelium-dependent hyperpolarization remains undetermined. We examined the ACh-induced hyperpolarization and its contribution to relaxation in arteries of SHR. Membrane potentials were recorded from the mesenteric artery trunk of 6-8-month-old male SHR and also Wistar-Kyoto (WKY) rats. Endothelium-dependent hyperpolarization to ACh was unaffected by NG-nitro-L-arginine, indomethacin, or glibenclamide; was reduced by tetraethylammonium or high K' solution; and was enhanced by low K' solution or methylene blue, thereby indicating that hyperpolarization is not mediated by nitric oxide (endothelium-derived relaxing factor) but is presumably mediated by a hyperpolarizing factor and is due to an opening of K' channels that probably differ from the ATP-sensitive ones. Hyperpolarizations to ACh were markedly reduced in SHR compared with findings in WKY rats (maximum, 8±1 versus 17±1 mV). In addition, under conditions of depolarization with norepinephrine (10-5 M), the ACh-induced hyperpolarization was even less and transient in SHR, while it was large and sustained in WKY rats (6±1 versus 29±2 mV

The temperature-sensitive BHK21 hamster cell line tsBN67 ceases to proliferate at the nonpermissive temperature after a lag of one to a few cell divisions, and the arrested cells display a gene expression pattern similar to that of serum-starved cells. The temperature-sensitive phenotype is reversible and results from a single missense mutation-proline to serine at position 134-in HCF, a cellular protein that, together with the viral protein VP16, activates transcription of herpes simplex virus (HSV) immediate-early genes. The tsBN67 HCF mutation also prevents VP16 activation of transcription at the nonpermissive temperature. The finding that the same point mutation in HCF disrupts both VP16 function and the cell cycle suggests that HCF plays a role in cell-cycle progression in addition to VP16-dependent transcription.[Key Words: tsBN67; HCF protein,-VP16 function,-GQ/GI cell cycle arrest; transcription] Received November 14, 1996; accepted in revised form February 7, 1997.Conditional mutations, particularly temperature-sensitive mutations, have been valuable tools for clarifying cell-cycle regulation in yeast as well as mammalian cells (for review, see Marcus et al. 1985). Previously, we have isolated a series of temperature-sensitive cell-proliferation mutants from the hamster BHK21 cell line (Nishimoto and Basilico 1978;Nishimoto et al. 1982). Following mutagenesis with N-methyl-N'-nitro-JV-nitrosoguanidine, mutants that proliferate at the permissive temperature of 33.5°C but not at the nonpermissive temperature of 39.5°C were concentrated through multiple rounds of negative selection with the cytotoxic base analog 5-fluoro-2-deoxyuridine to eliminate proliferating cells at the elevated temperature. Based on the ability of hybrid cells created by the fusion of different mutant lines to grow at the nonpermissive temperature, these temperature-sensitive lines have been classified into 25 complementation groups (Nishimoto and Basilico 1978;Nishimoto et al. 1982).To identify the genes affected by these mutations, human DNA has been used to complement the hamsterPresent address:

Serial changes in urine protein, blood chemistry, and histology of the kidney were investigated in rats for 28 weeks after injections of adriamycin (ADR). Massive proteinuria, hypoalbuminemia, and hyperlipidemia were observed at week 4 and throughout the experiment. Both BUN and serum creatinine began to increase at week 16 and reached the uremic level at week 28. Light microscopic study of the kidney demonstrated a normal appearance at week 4, vacuole formation in glomerular tuft at weeks 8 and 12, focal and segmental glomerular sclerosis at weeks 16 and 20, and extensive glomerular sclerosis with tubulointerstitial degenerations at weeks 24 and 28. Immunohistologically, IgM with a small amount of IgG and C3 appeared in the sclerosing glomeruli from week 16. Aggregated human IgG, injected intravenously at week 24, had accumulated mainly in the glomeruli. Electron microscopy revealed degenerative changes of glomerular epithelial cells with small vacuoles in the cytoplasm at week 4. Size of vacuoles increased at the later stage. In conclusion, ADR produced chronic, progressive glomerular changes in rats, which led to terminal renal failure. The segmental glomerular sclerosis and IgM-dominant glomerular deposition in these animals are similar to pathological characteristics of focal and segmental glomerular sclerosis seen clinically.

We investigated seasonal variation in the incidence of cerebral stroke among the general population aged >40 years in November of 1961 in Hisayama, Japan. During the 24-year follow-up period, 311 cases of cerebrovascular diseases occurred. The date or month of onset was determined in 308 cases, of which 51 were classified as intracerebral hemorrhage, 223 as cerebral infarction, and 27 as subarachnoid hemorrhage. We observed a significant seasonality in the incidence of all stroke (p<0.01), of intracerebral hemorrhage (p<0.05), and of cerebral infarction (p<0.01), whereas subarachnoid hemorrhage had no significant seasonal pattern. Subjects <64 years of age showed a significant seasonal variation in the incidence of both intracerebral hemorrhage (p<0.05) and cerebral infarction (p<0.01). A significant seasonal pattern for the incidence of intracerebral hemorrhage was also noted among persons with hypertension (p<0.05) or a high serum cholesterol level (p<0.05), whereas such a pattern for cerebral infarction was documented among normotensive persons (p<0.05) and those with a low serum cholesterol level (p<0.01). In addition, the incidences of intracerebral hemorrhage and cerebral infarction were negatively correlated with mean ambient temperature (p<0.01 and p<0.05, respectively), and all stroke and intracerebral hemorrhage in men were significantly related to intradiurnal temperature change (/><0.05 and p<0.01, respectively). and Denmark 13 ; there is agreement among these reports that the incidence of onset of cerebrovascular diseases peaks in the winter-spring and has a trough in the summer-autumn, related to ambient temperature. On the other hand, reports from Yugoslavia, 14 Mexico, 15 and Brazil 16 have found no seasonality or relation to temperature in stroke rates. However, data for all those studies were based on hospitalized patients or mortality statistics. Little is known about seasonality of the incidence of cerebrovascular diseases among the general population.From the Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan.Supported in part by research grants for Cardiovascular Disease from the Ministry of Health and Welfare, Japan, and facilitated by the Japan-U.S. Cooperative Agreement in the Cardiovascular Area, the Japanese National Cardiovascular Center, and the National Heart, Lung, and Blood Institute.Address for correspondence: Atsushi Shinkawa, MD, Second Department of Internal Medicine, Faculty of Medicine, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, 812 Japan. Received October 13, 1989; accepted April 23, 1990.The aim of our study is to elucidate in a long-term prospective population survey conducted in Hisayama, Japan, the seasonal variation in the incidence of stroke and the influence of traditional risk factors for cerebrovascular diseases and environmental factors on the seasonality of the onset of cerebrovascular diseases. We selected sex, age at onset, blood pressure, and serum cholesterol concentration as the traditional risk facto...

To elucidate the effect of glucose intolerance on cardiovascular disease in the current Japanese population, we performed a 75-g oral glucose tolerance test in 2,427 Hisayama residents aged 40-79 years in 1988, who were free from a previous history of stroke or myocardial infarction, and followed them prospectively for 5 years. The prevalence of diabetes (NIDDM) among men was 13% and that of impaired glucose tolerance (IGT) was 20%; the corresponding values for women were 9 and 19%, respectively. The age- and sex-adjusted incidence of cerebral infarction (6.5 per 1,000 person-years, P < 0.01) and coronary heart disease (5.0 per 1,000 person-years, P < 0.05) was significantly higher in subjects with NIDDM than in those with normal glucose tolerance (1.9 and 1.6 per 1,000 person-years, respectively). In addition, subjects with IGT and NIDDM had a higher risk of cardiovascular disease including stroke and coronary heart disease than did those with normal glucose tolerance after adjustment for age and sex, namely the relative risk for IGT was 1.9 (95% CI 1.2-3.2), and the relative risk for NIDDM was 3.0 (95% CI 1.8-5.2). These associations remained significant even after controlling for six other risk factors including hypertension in multivariate analysis. Our data suggest that NIDDM is a significant risk factor for both cerebral infarction and coronary heart disease and also that IGT itself is a risk factor for cardiovascular disease in the general Japanese population today.

This study was undertaken to compare age-related changes in endothelium-dependent vascular responses in both hypertensive and normotensive rats. Aorta from normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) aged 4-6 weeks (young), 3-6 months (adult), and 12-25 months (old) were examined for relaxation to acetylcholine, adenosine 5'-triphosphate (ATP), and sodium nitroprusside. Rubbed (endothelium denuded) aorta from all groups displayed neither relaxation nor contraction to acetylcholine. Maximal relaxation responses to acetylcholine were reduced progressively with increasing age in unrubbed aorta of both SHR and WKY rats. In addition, acetylcholine caused not only dose-dependent relaxations at lower concentrations but also increases in tension at higher concentrations in unrubbed aorta of old WKY rats as well as adult and old SHR. However, indomethacin completely inhibited the tension development. As a result, aorta treated with indomethacin demonstrated similar acetylcholine-induced, endothelium-dependent relaxations in all groups. The thromboxane A 2 synthetase inhibitor (E)-7-phenyl-7-(3-pyridyl)-6-heptanoic acid (CV-4151) partially but significantly depressed the increases in tension in aorta of old WKY rats. The degrees of endothelium-dependent relaxations to ATP and endothelium-independent relaxations to sodium nitroprusside were almost similar in all groups. These findings suggest that the release of or vascular responsiveness to endothelium-derived relaxing factor in the aorta is well maintained through senescence in both strains and that, in the aorta of not only SHR but also old normotensive WKY rats, the endothelium releases contracting factors that may be thromboxane A 2 and other vasoconstrictor prostanoids. (Hypertension 1989;14:542-548)