Phasic contractions of canine and human coronary arteries induced by potassium channel blockers

To gain insight into mechanisms underlying phasic coronary vasospasm in patients with variant angina pectoris, we studied whether phasic contractions could be induced in isolated canine and human coronary arteries by agents which block potassium channels. Phasic contractions of canine coronary arteries were always induced by 3,4-diaminopyridine (10(-2) M) and less frequently by 4-aminopyridine (10(-2) M). These agents also caused phasic contractions in human, swine and monkey coronary arteries and in canine basilar, carotid, renal and femoral arteries. The cycle length of phasic coronary contractions ranged from 30 sec to 1 hour, and the developed tension was 2.5 times greater than for potassium contractions. The contractions continued for more than 11 hours. Morphologically, perinuclear vacuolization, a characteristic change of vasospasm, appeared in the coronary smooth muscles. The phasic contractions were not eliminated by tetrodotoxin, atropine, phentolamine or yohimbine, but they were eliminated by nicorandil which activates potassium channels and nifedipine which blocks slow calcium channels. The results indicate that potassium channel blockers can induce phasic arterial contractions.     

Effects of insulin on vasoconstriction induced by thromboxane A2 in porcine coronary artery

To elucidate the role of insulin in the control of coronary artery tone, its effects on porcine coronary artery contraction evoked by thromboxane A2 (TXA2) were studied in vitro. Ring preparations of porcine proximal coronary artery were suspended in a Magnus apparatus filled with Tyrode's solution at 37 degrees C and aerated with 100% O2, and the isometric tension of the contractions was measured. Insulin itself caused neither contraction nor relaxation. Insulin had no significant effect on the coronary artery contractions evoked by 20 mM K+, norepinephrine, histamine, and serotonin; however, 120 minutes of preincubation with a physiological concentration of insulin (30-300 muunits/ml) significantly accentuated coronary artery contractions evoked by STA2 (10(-11) to 10(-7) M), a stable analogue of TXA2 that is known to act on TXA2/prostaglandin H2 receptors (141.4 +/- 10.9% of the control at 10(-7) M STA2 in the presence of 300 muunits/ml insulin; p less than 0.01). The enhancing effects of insulin on the STA2-induced contractions were affected by extracellular glucose or magnesium ion concentrations. The enhancing effects of insulin were observed only at the glucose concentrations of 100-300 mg/dl and magnesium concentrations of 0.5-1.5 mM. Therefore, insulin was suspected of enhancing TXA2-induced contraction through a process that depends on extracellular glucose and Mg2+.     

Effect of dilazep on hemoglobin-oxygen affinity in patients with ischemic heart disease

The effects of orally administered dilazep, an antianginal drug, on the hemoglobin-oxygen affinity were studied in 31 cases with ischemic heart disease. Prior to medication, the mean P50 value was 29.2 +/- 1.65 mmHg. There were no significant differences in the P50 value according to the age of patient or the severity of the coronary arterial disease. Acute effects of dilazep were studied in 29 patients. The 30 min and 60 min post-administration P50 values increased significantly to 30.2 +/- 2.55 mmHg and 30.4 +/- 2.31 mmHg, respectively. Eight patients were administered 300 mg of oral dilazep daily for 4 weeks. Three of 4 in whom exercise tolerance improved showed increases in P50. No changes in various factors which might affect the P50 value, including 2,3-DPG, were found.     

Pseudomyxoma peritonei due to adenocarcinoma of the lung: Case report

A rare case of pseudomyxoma peritonei whose primary site was presumed to be the lung is reported. A 76-year-old woman was admitted to Hospital presenting with progressive abdominal distention. She had been admitted twice, 2 and 1 year previously for the evaluation of high plasma carcinoembryonic antigen (CEA) level, of 11.6ng/ml. Chest computed tomography (CT) scan and chest X-ray film on the third admission revealed a nodular lesion in the left lower lung field, and transbronchial lung biopsy (TBLB) revealed mucus-producing tall columnar epithelial carcinoma. Paracentesis revealed gelatinous ascitic fluid. At laparotomy, appendix and ovary were normal, and there were many small cystic tumors on the peritoneal surface and omentum. The patient died 2 years later, after repeated episodes of dynamic ileus. The lung and abdominal tumors gradually increased in size during the 2-year period, but she developed no respiratory symptoms. Based on both the clinical and pathophysiological findings, the final diagnosis made was pseudomyxoma peritonei whose origin was a lung adenocarcinoma.     

Forearm venous distensibility in relation to severity of symptoms and hemodynamic data in patients with congestive heart failure

The distensibility of the forearm veins in 24 patients with congestive heart failure was studied by occlusion plethysmography. Relationships between forearm venous distensibility and symptoms, hemodynamic data obtained by right heart catheterization and plasma levels of vasoactive hormones were evaluated. Forearm venous pressure (VP) and volume change (delta V) were measured simultaneously by the venous occlusion technique with strain gauge plethysmography. The relationship between venous pressure and volume change was fitted by the equation VP = c* exp (k* delta V) (r = 0.98 +/- 0.01) and the venous stiffness constant (k) was calculated. Venous volume change at a venous pressure of 20 mmHg (V20) was also measured as another index of venous compliance. The pressure-volume curve of the peripheral veins shifted leftward on the volume axis and the stiffness constant (k) increased as the New York Heart Association functional class grade increased. Mean pulmonary arterial pressure and pulmonary vascular resistance were closely related to k (r = 0.74, p less than 0.001; r = 0.73, p less than 0.001, respectively), and less closely to V20 (r = -0.56, p less than 0.004; r = -0.59, p less than 0.002, respectively). K and V20 were also related to stroke index (r = -0.57, p less than 0.004; r = 0.44, p less than 0.03, respectively) and stroke work index (r = -0.47, p less than 0.02; r = 0.45, p less than 0.03, respectively). K was also related to heart rate (r = 0.55, p less than 0.007), pulmonary capillary wedge pressure (r = 0.54, p less than 0.02), right atrial pressure (r = 0.51, p less than 0.02), cardiac index (r = -0.45, p less than 0.03), and systemic vascular resistance (r = 0.45, p less than 0.03). Both indexes were related to the plasma level of norepinephrine (r = 0.64, p less than 0.008; r = -0.52, p less than 0.04, respectively). We concluded that the venous tone was related to the severity of heart failure, especially to the symptoms, pulmonary arterial pressure and plasma concentration of norepinephrine, and that the venous stiffness constant, k, was a better parameter with which to assess peripheral venous tone.     

Criterion validity of the cross-cultural cognitive examination in Japan.

Criterion validity of a two-stage Cross-Cultural Cognitive Examination (CCCE) designed for epidemiologic use was evaluated in Japanese subjects by comparison with a physician's DSM-III-R diagnosis of dementia and the Hasegawa Dementia Rating Scale (the standard Japanese instrument similar to the Mini-Mental State Exam). We report on 188 subjects tested in three locations in Japan: Tokyo area, Ise, and Osaka. Subjects ranged in age (50-93 years) and education (1-22 years) and included neurology outpatients, community volunteers, and inpatients. The CCCE was 97.4% specific for dementia, with sensitivity of 88%. The correlation with the Hasegawa scale was significant (r(175) = .8230, p less than .0001). Diagnosis using the CCCE showed good validity when compared with Japanese criteria for dementia. If the instrument could be shown to be reliable and more "culture fair" than the currently available tests, it may be useful in cross-cultural epidemiologic studies of dementia.