Inter-cohort differences in coronary heart disease mortality in the 25-year follow-up of the seven countries study

Sixteen cohorts of men aged 40–59 years at entry were examined with the measurement of some risk factors and then followed-up for mortality and causes of death for 25 years. These cohorts were located in the USA (1 cohort), Finland (2), the Netherlands (1), Italy (3), the former Yugoslavia (5), Greece (2), and Japan (2), and included a total of 12,763 subjects.Large differences in age-adjusted coronary heart disease (CHD) death rates were found, with extremes of 45 per 1000 in 25 years in Tanushimaru, Japan, to 288 per 1000 in 25 years in East Finland. In general, higher rates were found in the US and Northern European cohorts as compared to the Southern European and Japanese cohorts. However, during the last 10 years of follow-up large increases of CHD death rates were found in some Yugoslavian areas. Out of 5 measured entry characteristics treated as age-adjusted levels (serum cholesterol, systolic blood pressure, cigarette smoking, body mass index and physical activity at work), only serum cholesterol was significant in explaining cohort differences in CHD death rates.Over 50% of the variance in CHD death rates in 25 years was accounted for by the difference in mean serum cholesterol. This association tended to decline with increasing length of follow-up, but this was due to the great changes in mean serum cholesterol in the two Jugoslavian cohorts of Velika Krsna and Zrenjanin. When these two cohorts were excluded the association increased with time.Changes in mean serum cholesterol between year 0 and 10 helped in explaining differences in CHD death rates from year 10 onward.It can be concluded that this study suggests that mean serum cholesterol is the major risk factor in explaining cross-cultural differences in CHD.     

A new method of retrograde cardioplegic administration. Right ventricular protection by right atrial perfusion cooling

Retrograde administration of cardioplegic solution via the right atrium with continuous cooling of the right ventricular cavity (right atrial perfusion cooling) was assessed for its protective effect in 12 dogs with occlusion of the right coronary artery subjected to global ischemia for 60 minutes. After an initial administration of 4 degrees C crystalloid cardioplegic solution by antegrade aortic perfusion, myocardial protection was established either by right atrial perfusion cooling (group I; n = 6) or by antegrade aortic perfusion alone (group II; n = 6). The right ventricular temperature was approximately 15 degrees C in group I and 20 degrees C in group II. After ischemia for 60 minutes, the adenosine triphosphate content of the right ventricular free wall was significantly higher in group I than in group II (24.4 +/- 1.45 versus 13.8 +/- 2.34 mumol/gm dry weight, p less than 0.05). The percent recovery of right ventricular contractility, which was evaluated by end-systolic pressure-volume relationships, was significantly better in group I at each reperfusion period (30 minutes: 130.0% +/- 9.6% versus 86.1% +/- 11.8%, p less than 0.05; 60 minutes: 159.6% +/- 12.9% versus 96.5% +/- 20.1%, p less than 0.05). Postischemic right ventricular stiffness (reciprocal value of compliance) increased in group II compared with group I, although the difference was not statistically significant. There were no major differences in percent recovery of the left ventricular end-systolic pressure-volume relationships between the two groups. The evidence suggests that the right atrial perfusion cooling method produces excellent right ventricular protection.     

Molecular design of biodegradable functional polymers, 3. Biodegradability and functionality of poly[(sodium acrylate)-co-(vinyl alcohol)]

As a design for a biodegradable functional polymer, compositionally homogeneous poly[(sodium acrylate)-co-(vinyl alcohol)] [P(SA-co-VA)], containing varying amounts of vinyl alcohol groups as biodegradable segments were prepared and their biodegradability and builder performance in detergent formulations were analyzed with respect to the successive vinyl alcohol length. It was found that the acrylate copolymers having more than 80 mol-% vinyl alcohol content showed biodegradability. That is, P(SA-co-VA) having a vinyl alcohol chain length of more than about 5–6 is cleaved by PVA-degrading microbes. This indicates that the vinyl alcohol blocks, which act as biodegradable segments, should be incorporated into the polymer chain in such a manner that they are accepted as substrates by the PVA-degrading enzymes.     

A comparative study of portal vein embolization versus radiation lobectomy with Yttrium-90 micropheres in preparation for liver resection for initially unresectable hepatocellular carcinoma

BackgroundPortal vein embolization before liver resection is considered the therapy of choice for patients with inadequate future liver remnants. The concept of radioembolization with Yttrium-90 to achieve the same goal has limited data.MethodsWe retrospectively compared patients who underwent portal vein embolization and Yttrium-90 lobectomy before resection of hepatocellular carcinoma in patients with chronic liver disease.ResultsSeventy-three patients underwent portal vein embolization and 22 patients underwent Yttrium-90. Forty-seven percent of patients before portal vein embolization required additional procedures for tumor control, and 27% of patients after Yttrium-90 required additional procedure to mainly induce further hypertrophy. Both therapies achieved the goal of future liver remnants >40%, but the degree of hypertrophy was significantly higher in Yttrium-90 patients (63% for Yttrium-90, 36% for portal vein embolization, P < .01). Tumor response was significantly better with Yttrium-90, achieving complete response in 50% of patients. Resectability rate was higher after portal vein embolization (85% for portal vein embolization, 64% for Yttrium-90, P = .03). Tumor progression was the most common reason precluding surgery. Complete tumor control was the reason not to pursue surgery in 18% of patients after Yttrium-90.ConclusionBoth preoperative portal vein embolization and Yttrium-90, increases liver resectability rates by inducing hypertrophy of future liver remnants in patients with hepatocellular carcinoma and chronic liver disease. Yttrium-90 lobectomy achieved better tumor control and provided more time to assess therapy response, optimizing the indication for surgery.     

Tricuspid valve replacement in a patient with idiopathic tricuspid regurgitation]

Tricuspid regurgitation is often seen but is rarely categorized as "idiopathic". A 66-year-old man suspected of idiopathic tricuspid regurgitation underwent tricuspid valve replacement. With right heart failure over twenty years, his CTR increased to eighty six (86) per cent. During operation, no abnormal findings were observed except for the dilated tricuspid valve ring. Then a stented porcine xenograft (Carpentier-Edwards 33 mm) was inserted in the tricuspid valve annulus. Seven years after replacement, he died. Autopsy demonstrated myocardial hypertrophy of the right ventricle and dilatation of the right heart, supporting the diagnosis of idiopathic tricuspid regurgitation.     

Inhibition of enamel demineralization and bond‐strength properties of bioactive glass containing 4‐META/MMA‐TBB‐based resin adhesive

We investigated the enamel demineralization‐prevention ability and shear bond strength (SBS) properties of 4‐methacryloxyethyl trimellitic anhydride/methyl methacrylate‐tri‐n‐butyl borane (4‐META/MMA‐TBB)‐based resin containing various amounts (0–50%) of bioactive glass (BG). Disk‐shaped specimens were immersed in distilled water and ions released were analysed by inductively coupled plasma atomic‐emission spectroscopy. Samples were also immersed in lactic acid solution (pH 4.6) to estimate acid‐neutralizing ability. Brackets were bonded to human premolars with BG‐containing resins and the bonded teeth were alternately immersed in demineralizing (pH 4.55) and remineralizing (pH 6.8) solutions for 14 d. The enamel hardness was determined by nanoindentation testing at twenty equidistant distances from the external surface. The SBS for each sample was examined. The amounts of ions released [calcium (Ca), sodium (Na), silicon (Si), and boron (B)] and the acid‐neutralizing ability increased with increasing BG content. After alternating immersion, the specimens bonded with the BG‐containing resin with high BG content were harder than those in the other groups in some locations 1–18.5 μm from the enamel surface. Bioactive glass‐containing (10–40%) resin had bond strength equivalent to the control specimen. Thus, the SBS obtained for BG‐containing resin (6.5–9.2 MPa) was clinically acceptable, suggesting that this material has the ability to prevent enamel demineralization.     

Inhibition of enamel demineralization by buffering effect of S‐PRG filler‐containing dental sealant

The buffering capacity and inhibitory effects on enamel demineralization of two commercially available dental sealants were evaluated in this study. The effects of filler particles were also examined. Disks of enamel and cured sealant materials of BeautiSealant (silica or S‐PRG filler) or Teethmate F‐1 were incubated in lactic acid solutions (pH 4.0) for 1–6 d. The pH changes and amounts of ions released in the solutions were assessed, and enamel surfaces were observed using a scanning electron microscope. The pH of the solution with BeautiSealant (S‐PRG filler) was neutralized from pH 4.0 to pH 6.1 (after incubation for 1 d) and from pH 4.0 to pH 6.7 (after incubation for 6 d). In addition, no release of calcium ions was detected and the enamel surface was morphologically intact in scanning electron microscopy images. However, the pH of the solution with Teethmate F‐1 remained below pH 4.0 during incubation from days 1 to 6. Calcium release was increased in solutions up to and after 6 d of incubation. Scanning electron microscopy images showed that the structures of hydroxyapatite rods were exposed at the specimen surfaces as a result of demineralization. Ions released from S‐PRG filler‐containing dental sealant rapidly buffered the lactic acid solution and inhibited enamel demineralization.     

Changes of left ventricular pressure-diameter-velocity relations by alterations of heart rate in conscious dogs

Changes of left ventricular (LV) pressure-diameter-velocity relations by alterations in heart rate (HR) were investigated in 6 conscious dogs, instrumented with a pair of ultrasonic crystal probe, a micromanometer in LV and pacing electrodes on the left atrium. By atrial pacing the following four stages of HR were produced: stage (S)-I 112, S-II 134, S-III 158 and S-IV 179 bpm (mean HR). These alterations in HR were repeated before and during acute pressure loadings by methoxamine infusion. LV pressure-diameter and pressure-velocity relations were evaluated by the slope value of LV peak systolic pressure (LVSP)-end-systolic diameter, E (D) max, and by the ratio of changes in mV cf (mean velocity circumferential fiber shortening) and LVSP before and during pressure loading, delta mVcf/delta LVSP, respectively. The average of E(D) max at each stage of HR was 9.45, 12.63, 12.59, 11.22 mmHg/mm, and delta mVcf/delta LVSP was -0.009, -0.006, -0.007, -0.009 circ./sec.mmHg, respectively. E(D) max increased more at S-II and S-III than at S-I, and reversely, E(D) max decreased more at S-IV than at S-II. Similarly, delta mVcf/delta LVSP increased more at S-II than at S-I and decreased more at S-IV than at S-II, while delta LVSP and delta EDD (end-diastolic diameter) were not different between stages. These changes in E(D) max and delta mVcf/delta LVSP presented the mountainous pattern effected by alterations in HR, whose changes were almost similar to that of LV peak positive dp/dt and mVcf before pressure loading. Thus, E(D) max is augmented by an increase in HR, which suggests the Bowditch-effect. Reversely, a decrease in E(D) max at a higher rate indicates a depressed inotropic state. E(D) max is dependent on HR and is a sensitive indicator of the contractility of LV.     

Relationship of exercise or pacing induced ST segment depression and myocardial lactate metabolism in patients with hypertrophic cardiomyopathy

To elucidate a mechanism and clinical implications of chest pain and ST segment depression during exercise in patients with hypertrophic cardiomyopathy (HCM), we investigated myocardial lactate metabolism during atrial pacing in 18 patients with HCM and 7 control subjects with normal coronary arteriograms. At an average peak pacing rate of 146 beats/min, 11 patients with HCM showed the lactate extraction ratio decreasing to less than 5%, and 6 of them produced lactate, suggesting the development of myocardial ischemia. These 11 patients with abnormal lactate metabolism demonstrated ST segment depression (82%) and chest pain (73%) during pacing and also presented abnormal results (55%) on an exercise stress test. These abnormal findings were not observed in the other 7 patients who had ratios of 5% or more at peak pacing. These observations suggest that ST segment depression and chest pain are manifestations of myocardial ischemia even in patients with HCM who have normal coronary arteriograms, and that patients with pacing induced abnormal lactate metabolism are at an increased risk of developing myocardial ischemia during exercise.     

Effects of oral befunolol on heart rate and systolic blood pressure during submaximal exercise in man

For the purpose of determining exercise intensity required for evaluating the effect of beta-blocking agents, the multi-stage treadmill exercise was carried out up to intensity of 85% of maximal oxygen intake (VO2max) after administration of beta-blocking agents in 7 healthy men. To obtain a stable dose response in the inhibitory effect of beta-blocking agents on heart rate (HR) and systolic blood pressure (S-BP), the exercise intensity more than 65% of VO2max (75% of maximal heart rate) was needed. In order to evaluate the effect of befunolol (BFE), a submaximal treadmill exercise of 75% of the age adjusted predicted maximal heart rate was loaded in 6 healthy men at 1.5, 4, and 8 hours following a single oral administration of 10 mg, 20 mg or 40 mg of BFE and 20 mg or 40 mg of propranolol. Simultaneously, the plasma concentration of BFE was determined 1.5, 4, 6 and 8 hours after the administration of BFE at each dose. In human serum, BFE was detected together with its metabolite, revealing a significant correlation between BFE and metabolite (r = 0.94, p < 0.001). Almost a certain rate of metabolite (4--5 times) was detected against BFE. As for the biological half life, it was 1.79 +/- 0.13 hours with BFE and 3.67 +/- 1.33 hours with metabolite. The inhibitory effect of BFE on HR and S-BP during exercise exhibited a dose response with the oral dose and its plasma concentration, and was almost twice as much as that of propranolol at the same dose. Accordingly, the myocardial oxygen consumption which may be represented as rate pressure product was inhibited twice as much as propranolol. BFE is characteristic of its more rapid elimination of its effect compared to the other beta-blocking agents. The decrease in the inhibitory effect of BFE or HR during exercise was about 1.8 times quicker than that of propranolol.