Factors relate to participation in medical checkups in a rural community an analysis including social network scores]

Since 1969, community-based stroke prevention programs have been conducted in N town, Kochi prefecture. To clarify factors related to participation in medical checkups including social networks, a cross-sectional questionnaire survey was performed on 6,704 residents aged 40 and over in N town in 1996. 1. Location of the workplace, types of medical insurance and interest in health were significantly associated with participation in medical checkups. 2. Participation in medical examinations provided at the workplace was significantly, inversely related with participation rates in community checkups in the group aged 40 to 59 years. 3. Low independence level in daily activities was inversely associated with participation rates for medical checkups in groups aged 60 years and older. 4. Visiting medical facilities was inversely associated with the participation rate for medical checkups in female groups. 5. The group with the highest social networks score (5 points) had the highest participation rate for medical checkups. After adjusting for other participation related factors, social networks scores had a significantly positive association with the participation rate for medical checkups provided by the Health Services for the Elderly Act.     

The anti-ischemic effects of CP-060S during pacing-induced ischemia in anesthetized dogs

CP-060 S, (-)-( S)-2-[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]-3-[3-[N-methyl-N-[2-(3 ,4-methylenedioxyphenoxy)ethyl]-amino]propyl]-1,3-thiazolidin++ +-4-one hydrogen fumarate, is a novel cardioprotective drug which prevents Na+-, Ca2+-overload and has Ca2+ channel blocking activity. We compared the anti-ischemic effects of CP-060S with those of diltiazem, a Ca2+ channel blocker, and R56865, N-[1-[4-(4-fluorophenoxy)butyl]-4-piperidinyl]-N-methyl-2-benzothiazo lamine, a Na+-, Ca2+-overload inhibitor, in a canine pacing-induced ischemia model. CP-060S 100 microg kg(-1) significantly suppressed the pacing-induced ischemic epicardial ST-segment elevation by maximally 75%, while diltiazem 100 microg kg(-1) suppressed it by maximally 35%. R56865 100 microg kg(-1) significantly suppressed the ST-segment elevation by maximally 30%. In addition, diltiazem 100 microg kg(-1) caused synergistic suppression of ST-segment elevation by 70% when administered simultaneously with R56865 100 microg kg(-1). These results suggest that a Na+-, Ca2+-overload preventive action and a Ca2+ channel blocking action independently contribute to the suppression of the ST-segment elevation. Therefore, CP-060S may suppress pacing-induced ST-segment elevation by a dual action by preventing Na+-, Ca2+-overload and the Ca2+ channel blockade.     

Effects of a class III antiarrhythmic drug, dofetilide, on the in situ canine heart assessed by the simultaneous monitoring of hemodynamic and electrophysiological parameters

The cardiovascular profile of dofetilide was examined using halothane-anesthetized, closed-chest in vivo canine model (n=6). Dofetilide was administered at the dose of 1, 10 or 100 microg/kg, i.v. over 10 min with a pause of 20 min. After the lowest infusion rate, no significant change was detected in any of the cardiovascular parameters. Infusion of 10 microg/kg dofetilide, which was close to the submaximal clinically effective antiarrhythmic dose, decreased the heart rate and prolonged the ventricular repolarization phase and refractory period. After the highest dose of dofetilide, the cardiac output and left ventricular contraction decreased during sinus rhythm, the latter of which was not changed during the constant heart rate of 150 beats/min, while the dose-related effects were observed on the heart rate, repolarization phase and refractory period. The afterload and preload to the left ventricle and AV nodal as well as intraventricular conductions were hardly affected even at 100 microg/kg, i.v. These results obtained in the in vivo canine model support the previous reports describing that dofetilide possesses a highly selective blocking property for I(Kr). Moreover, the absence of effects on the afterload and preload to the left ventricle and the cardiac conduction makes dofetilide favorable as an antiarrhythmic drug because it is often used for patients with moderate to severe left ventricular dysfunction.     

Tomographic analysis of CBF in cerebral infarction

Cerebral perfusion was examined in various types of occlusive disease by computed tomographic CBF method. The method utilized has several advantages over conventional studies using isotope, providing high resolution images in a direct relation to CT anatomy. Ten representative cases were presented from 25 consecutive cases of occlusive disease studied by this method. The method included inhalation of 40 to 60% xenon with serial CT scanning for 25 min. K (build-up rate), lambda (partition coefficient) and CBF values were calculated from HU for each pixel and Xe in expired air, based on Fick's principle, and displayed on CRT as K-, lambda- and CBF-map separately. CBF for gray matter of normal control was 82 +/- 11 ml/100 gm/min and that for white matter was 24 +/- 5 ml/100 gm/min. The ischemic threshold for gray matter appeared to be approximately 20 ml/100 gm/min, as blood flow in focus of complete infarction was below this level. Blood flow between 20-30 ml/100 gm/min caused some change on CT, such as localized atrophy, cortical thinning, loss of distinction between gray and white matter and decreased or increased density, which were considered to be compatible with pathological changes of laminar necrosis or gliosis with neuronal loss. In a case with occlusion of middle cerebral artery with subsequent recanalization, causing hemorrhagic infarct, hyperemia was observed in the infarcted cortex that was enhanced by iodine. Periventricular lucency observed in two cases, where blood flow was decreased below threshold, could be classified as "watershed infarction" mainly involving white matter. In moyamoya disease, blood flow in the anterior circulation was decreased near ischemic level, whereas that in basal ganglia and territory of posterior cerebral artery was fairly preserved, which was compatible with general angiographic finding of this disease.     

A comparative view of Rickettsia tsutsugamushi and the other groups of rickettsiae

Recent researches on the rickettsial group microorganisms are summarized in their comparative aspects of morphology, cultivation and multiplication, susceptibility to chemotherapeutics, chemical structure of envelopes, nucleic acid, protein constitution, and gene structures. From this overview, Rickettsia tsutsugamushi seems to have different properties from the others and should be reclassified into a new genus, and a new species name as Orientia tsutsugamushi is proposed.Presented at the 4th International Symposium on Rickettsiae and Rickettsial Diseases, Pietany, C.S.F.R., 1–6 October, 1990.     

Mechanisms underlying the slow onset of action of a new dihydropyridine,NZ-105, on a cultured smooth muscle cell line

Summary The inhibitory effect of a new dihydropyridine derivative, (±)-2-[benzyl(phenyl)amino]ethyl-1,4-dihydro-2,6-dimethyl-5-(5,5-dimethyl-2-oxo-1,3,2-dioxaphosphorinan-2-yl)-4-(3-nitrophenyl)-3-pyridinecarboxylate hydrochloride (NZ-105), on whole cell Ca²⁺ current (I_Ca) in cultured vascular smooth muscle cells was investigated with the patch clamp technique. NZ-105 blocked I_Ca in a concentration-dependent manner when the command pulse ranged from +10 mV to –50 mV. The inhibitory effect of NZ-105 appeared at concentrations higher than 10 mol/l and it blocked I_Ca completely at a concentration of 1 nmol/l. The concentration which produced the half-maximal inhibitory effect was estimated to be around 20 mol/l. NZ-105 (500 pmol/l) completely blocked I_Ca elicited by depolarization to + 10 mV at a holding potential of –40 mV, whereas it blocked I_Ca by only 67% at a holding potential of –90 mV. NZ-105 (100 mol/l) shifted the steady-state inactivation curve by 40 mV to more negative potentials without affecting its slope factor. The blocking time constant of 500 mol/l NZ-105 was 57.6 + 9.9 s at a holding potential of –70 mV. These results indicate that NZ-105 has characteristics typical of dihydropyridines and binds to Ca²⁺ channels of vascular smooth muscle cells with a high affinity. They also suggested that the slow onset of its action is due to the slow binding of the drug to Ca²⁺ channels. Send offprint requests to S. Kokubun at the above address     

A basic study on the association of Epstein-Barr virus with nasopharyngeal carcinoma--detection and genotypic analysis of Epstein-Barr virus associated with nasopharyngeal carcinoma in Japanese patients]

Epstein-Barr virus (EBV) is known to be associated with two human malignant diseases, nasopharyngeal carcinoma (NPC) and endemic Burkitt's lymphoma. In this study, the genotypes of EBV in tissues from 13 NPC patients in Japan were analyzed by Southern blot hybridization using EBV genome fragment probes. Ten of the cases contained reiterated sequences (EBV BamHI-H, -B1*, -K fragments), showing that only one genotype was detected in each specimen. One of these had a BamHI fragment containing a fused sequence of BamHI-Y and -H. In all except one case, a single-sized EBV-joined terminus was observed in each NPC specimen, implying evolution of the carcinoma from a single EBV-infected cell. One metastatic lymph node (which was not a primary epipharyngeal tumor) contained EBV with heterogeneous termini suggesting production of linear virion DNA. The type C variant resulting from loss of a BamHI site between the BamHI-W1* and -I1* regions was observed in 7 of the 10 cases, and the other 3 cases had a separated BamHI-I1* fragment. As reported by Lung et al. (Virology, 177: 44-53, 1990), the type C variant appears to be dominant among Japanese strains, as it is in Southern China. In contrast to their findings, however, the "f" variant with an extra BamHI site in the BamHI-F region which they found to be strongly associated with NPC specimens from Southern China, was detected in only one case. The present study, therefore, did not support the specific association of the "f" variant with NPC in Japanese patients. We conclude that the EBV in NPC tissues exists in variants. Further studies along these lines, could help to explain the epidemiology of EBV.     

Three-dimensional observations on microvascular growth in rat glioma using a vascular casting method

The microvascular growth of ethylnitrosourea-induced rat glioma was observed using vascular casting and scanning electron microscopy (SEM). Light microscopy showed central necrosis and marginal invasive tumor cell growth with increased vascularity, and suggested that adopted pre-existing circulation was dominant in the inoculated brain tumors. In SEM, numerous buds or nodular protrusions and a few large and tortuous vessels along the tumor margin were seen at the early stage. In the intermediate stage, microaneurysms, buds with septum formation and anastomotic arches appeared, and these tumor vessels became more tortuous and larger, and extended as the tumor grew. Several "potato-shaped" huge vessels and linear nodular large vessels also appeared. In the late stage, glomeruli appeared and potato-shaped huge vessels increased in number. The neovascularization and microvascular growth of the tumors was characterized by three patterns: (a) growth of the parent vessels forming buds, (b) vascular growth in a meshwork formation producing glomeruli, and (c) vascular enlargement without a definite pattern creating potato-shaped huge vessels. The tumor vessels gradually lost their natural three-dimensional structure.