Clinical impact of predicting CCND1 amplification using plasma DNA in superficial esophageal squamous cell carcinoma

BACKGROUND

This study was designed to evaluate the clinical benefit of predicting the cyclin D1 (CCND1) status using cell-free plasma DNA in superficial esophageal squamous cell carcinoma (ESCC) patients.

METHODS

The ratio of the CCND1 (11q13) dosage to the DRD2 (11q22-23) dosage (C/D ratio) as the CCND1 copy number was evaluated. This study was divided into three steps: (1) demonstration of the feasibility, (2) evaluation of whether the plasma C/D ratio assay could monitor tumor dynamics, and (3) a validation study in 63 consecutive superficial ESCC (pTis-T1) patients and 40 healthy volunteers.

RESULTS

(1) The plasma C/D ratio was significantly higher (p = 0.0369) in superficial ESCC patients than in the controls in a preliminary test. (2) The high plasma C/D ratio appeared to reflect the tumor levels of the CCND1 status and was reduced in postoperative plasma samples (p = 0.1154) and samples following endoscopic resection (p = 0.0845). (3) Validation analysis revealed that the plasma C/D ratio was significantly higher in superficial ESCC patients than in controls (p < 0.0001). The frequency of recurrence was significantly higher (p = 0.0198), and recurrence-free survival was significantly shorter (p = 0.0075) in patients with a high plasma C/D ratio. Moreover, a high C/D ratio was shown to be an independent risk factor for recurrence on multivariate analysis [p = 0.0334; odds ratio 10.58 (range 1.203-93.23)].

CONCLUSION

The prediction of CCND1 amplification by plasma DNA may be a new complementary clinical biomarker for recurrence in patients with superficial ESCC.

Circulating miR-18a: a sensitive cancer screening biomarker in human cancer

MicroRNAs have been reported to be stably detectable in plasma/serum and to exhibit resistance to endogenous ribonuclease activity because of binding to proteins such as Argonaute-2 and high-density lipoprotein, or being packed by secretory particles such as exosomes. These secretory particles include specific microRNAs and can function as intercellular transmitters. These findings could open-up a new and promising field in the use of circulating microRNAs for cancer treatment. In particular, miR-18a, which is located in the potentially oncogenic miR-17-92 cluster, is a highly expressed microRNAs in several types of cancers. The concentration of miR-18a in plasma/serum of patients with cancer such as esophageal (AUC=0.944), pancreatic (AUC=0.936), hepatocellular (AUC=0.881), colorectal and other types of cancers is much higher than that of healthy volunteers. Such reports provide evidence that circulating miR-18 might be a next-generation biomarker and contribute to cancer screening in non-invasive liquid biopsy, to a clinically-satisfactory degree of sensitivity and specificity.

[Discrepancies in the histological grade of submucosal gastric carcinoma between biopsy and postoperative resected specimens]

BACKGROUND AND AIMS

This study was designed to evaluate the discrepancies in the histological grade of submucosal (SM) gastric carcinoma between biopsy and resected specimens graded using the Japanese classification of gastric carcinoma (JCGC) and TNM classifications.

SAMPLES AND METHODS

This study comprised 250 consecutive paired biopsy and curative gastrectomy resection specimens from SM gastric carcinomas obtained between 1995 and 2011.

RESULTS

Of the 250 SM gastric carcinomas, 47 (19%) were smaller than 1.5 cm. Of 32 biopsy specimens diagnosed as differentiated type according to the JCGC classification, only 1 (3.1%) was eventually diagnosed as undifferentiated type according to the resected specimen. In contrast, of 25 biopsy specimens diagnosed as differentiated type according to the TNM classification, 2 (8.0%) were eventually diagnosed as undifferentiated type according to the resected specimens. These specimens were all mixed-type carcinomas.

CONCLUSIONS

Mixed-type gastric carcinoma is associated with a high incidence of histological discrepancy between biopsy and resected specimens in both JCGC and TNM classification. For mixed-type gastric carcinoma in particular, the treatment strategy selected from the limited treatments options available should be based on the histological grade according to biopsy specimens.

Blockade of ATP-sensitive K+ channels attenuates preconditioning effect on myocardial metabolism in swine: myocardial metabolism and ATP-sensitive K+ channels

OBJECTIVE

We investigated if blockade of ATP-sensitive K+ channels (KATP) abolishes the protective effect of ischemic preconditioning (IP) on myocardial metabolism and ischemia-induced reactive hyperemia (RH) in pigs.

METHODS

IP was elicited by a single cycle of 5 min occlusion and 5 min reperfusion of coronary artery, followed by 15 min of test ischemia and 120 min of reperfusion. Vehicle or the ATP-sensitive K+ channels (KATP) blocker, glibenclamide (3 or 6 mg/kg; G3 or G6) was administered before IP (groups; IP, G3+IP, G6+IP). As respective controls, the same treatment was performed in groups without IP (groups; C, G3, G6). Tissue levels of ATP, creatine phosphate (CP) and intracellular pH (pHi) in the area at risk were measured by 31P-nuclear magnetic resonance spectroscopy. RH after 5 min of preconditioning ischemia was assessed by regional myocardial blood flow.

RESULTS

ATP and pHi were preserved after 15 min of ischemia in the IP group [C/IP; ATP=57+/-4/76+/-10% of baseline, pHi=6.18+/-0.08/6.66+/-0.03, P<0.05, C vs. IP]. Both doses of glibenclamide completely abolished the ATP sparing effect of IP. The high dose completely abolished pHi preservation (G6+IP=6.33+/-0.06), while the low dose showed only a partial effect (G3+IP=6.48+/-0.03). Glibenclamide did not adversely affect myocardial metabolism in groups without IP. Glibenclamide attenuated RH after 5 min of ischemia by 30% in both subendocardium and subepicardium.

CONCLUSIONS

Blockade of KATP abolished the preconditioning effect on myocardial metabolism, and partially attenuated post-ischemic reactive hyperemia in pigs. These results indicate that KATP activation might be involved in the mechanisms of these phenomena, reactive hyperemia is not sufficient to induce IP protection.

Activation of epsilon protein kinase C correlates with a cardioprotective effect of regular ethanol consumption

In addition to decreasing the incidence of myocardial infarction, recent epidemiological data suggest that regular alcohol consumption improves survival after myocardial infarction. We recently found that chronic ethanol exposure induces long-term protection against cardiac ischemia-reperfusion injury, which improves myocardial recovery after infarction. Furthermore, this cardioprotection by ethanol is mediated through myocyte adenosine A1 receptors. We now determine the role of protein kinase C (PKC) in ethanol's protective effect against ischemia-reperfusion injury. Using perfused hearts of ethanol-fed guinea pigs, we find that improved contractile recovery and creatine kinase release after ischemia-reperfusion are abolished by PKC inhibition with chelerythrine. Western blot analysis and immunofluorescence localization demonstrate that regular ethanol consumption causes sustained translocation (activation) of epsilonPKC, but not delta or alphaPKC. This same isozyme is directly implicated in ischemic preconditioning's protection against ischemia-reperfusion injury. Our findings suggest (i) that regular ethanol consumption induces long-term cardioprotection through sustained translocation of epsilonPKC and (ii) that PKC activity is necessary at the time of ischemia to mediate ethanol's protective effect against ischemia-reperfusion injury. Studying this selective effect of ethanol on epsilonPKC activation may lead to new therapies to protect against ischemia-reperfusion injury in the heart and other organ systems.

Alcohol consumption reduces ischemia-reperfusion injury by species-specific signaling in guinea pigs and rats

We recently discovered that regular alcohol consumption reduces ischemia-reperfusion injury to the same degree as ischemic preconditioning in guinea pig hearts. Ischemic preconditioning, like this cardioprotective effect of alcohol, is mediated by adenosine signaling in guinea pigs. In rats, ischemic preconditioning may be mediated predominantly by alpha1-adrenergic signaling. To be certain that this protective effect of alcohol is a general biological response, we searched for alcohol's cardioprotection in rat and identified a potential signaling mechanism. Hearts isolated from alcohol-fed guinea pigs and rats were subjected to ischemia-reperfusion. Hearts from alcohol-fed animals showed greater recovery of left ventricular developed pressure than controls (guinea pigs, 46 vs. 29%; rats, 50 vs. 31%) and decreased myocyte necrosis assessed by creatine kinase release (guinea pigs, 204 +/- 42 vs. 440 +/- 70 U . ml-1 . g dry wt-1; rats 158 +/- 13 vs. 328 +/- 31 U . ml-1 . g dry wt-1). Adenosine receptor blockade [8-(p-sulfophenyl)theophylline] abolished alcohol's protection in guinea pig but not rat hearts. By contrast, alpha1-adrenergic blockade (prazosin) abolished alcohol's protection in rat but not guinea pig hearts. We conclude that regular alcohol consumption reduces ischemia-reperfusion injury and is mediated by species-specific signaling mechanisms. A major goal of cardiovascular research is to find a pharmacologically induced chronic state of preconditioning. Understanding the mechanisms of alcohol's cardioprotection against ischemia-reperfusion injury may aid in reaching this goal.

Inorganic phosphate and coronary perfusion pressure mediate contractile dysfunction during mild ischemia

During mild graded ischemia in perfused rat hearts, we (V.M. Figueredo, R. Brandes, M. W. Weiner, B. M. Massie, and S. A. Camacho. J. Clin. Invest 90: 1794-1802, 1992) previously found a relationship between decreased left ventricular developed pressure (LVDP) and increased Pi, in which intracellular pH, cytosolic Ca2+ concentration ([Ca2+]i), ATP, and free-energy change of ATP hydrolysis were not altered enough to affect contractility. However, the contribution of decreased coronary perfusion pressure (CPP) to decreased LVDP could not be determined. Thus, in the present study, graded hypoxia in perfused rat hearts (95-37.5% O2) was used to increase Pi to similar levels produced during mild ischemia without altering CPP and minimizing changes of other potential mediators of contractile dysfunction. 31P-magnetic resonance spectroscopy and indo 1 fluorescence were used to assess energy metabolites and [Ca2+]i, respectively. The relationship between LVDP and Pi during graded hypoxia was fit to a monoexponential (LVDP = 105 x e-0.04Pi). These data were compared with the relationship of LVDP and Pi during mild ischemia (LVDP = 106 x e-0.08Pi) (V. M. Figueredo, R. Brandes, M. W. Weiner, B. M. Massie, and S. A. Camacho. J. Clin. Invest 90: 1794-1802, 1992). The exponential constant, which describes the effect of Pi on LVDP, was 50% lower during graded hypoxia relative to mild ischemia. This suggests that another mediator, which accounted for approximately 50% of the decrease of LVDP during mild ischemia, was not present during hypoxia. Because CPP decreased during ischemia but not hypoxia, these data suggest that CPP and Pi contribute similarly in mediating contractile dysfunction during mild ischemia.

Regular alcohol consumption mimics cardiac preconditioning by protecting against ischemia-reperfusion injury

Epidemiologic studies indicate that long-term alcohol consumption decreases the incidence of coronary disease and may improve outcome after myocardial infarction. Attenuation of ischemia-reperfusion injury after myocardial infarction improves survival. This study investigates the possibility that alcohol consumption can improve survival after myocardial infarction by reducing ischemia-reperfusion injury. Hearts were isolated from guinea pigs after drinking ethanol for 3-12 weeks and subjected to global ischemia and reperfusion. Hearts from animals drinking ethanol showed improved functional recovery and decreased myocyte damage when compared with controls. Adenosine A1 receptor blockade abolished the protection provided by ethanol consumption. These findings indicate that long-term alcohol consumption reduces myocardial ischemia-reperfusion injury and that adenosine A1 receptors are required for this protective effect of ethanol. This cardioprotective effect of long-term alcohol consumption mimics preconditioning and may, in part, account for the beneficial effect of moderate drinking on cardiac health.

Preconditioning with 15-minute ischemia extends myocardial infarct size after subsequent 30-minute ischemia in rabbits

Ischemic preconditioning (PC) induced by 1 cycle of 5-min coronary occlusion and 5-min reperfusion limits infarct size (IS) after 30-min sustained ischemia in rabbits. The shortest ischemic period that induces the PC effect in rabbits is 3 min. To establish the maximum ischemic period to induce a beneficial PC effect, we examined the effect of PC periods of 10 and 15 min on IS after sustained ischemia. The IS in control rabbit hearts after 30 min of sustained occlusion of the left anterolateral coronary artery and 48-h reperfusion was compared with that of hearts treated as follows before being subjected to PC: 5-min occlusion and 5-min reperfusion; 10-min occlusion and 5-min reperfusion; or 15-min occlusion and 5-min reperfusion. In addition, the IS after 15-min or 45-min occlusion and 48-h reperfusion was measured. There was no significant difference in blood pressure, heart rate, or area at risk (AAR) among the rabbits in 5 groups. The IS measured histologically was 40 +/- 4% of AAR in the control, 10 +/- 3% after 5-min PC, and 12 +/- 2% after 10-min PC. However, in the 15-min PC group, the IS was 77 +/- 4% of AAR, which was significantly larger than that of the controls, but similar to that of hearts subjected to 45-min ischemia and reperfusion (67 +/- 3%). As 15 min of preconditioning ischemia alone caused small infarcts (18 +/- 1% of AAR), the infarcts caused by sustained ischemia per se in the 15-min PC group was estimated to be 72 +/- 5% of AAR, which was still significantly higher than in the control groups. We conclude that the maximum period of preconditioning ischemia that induces cardioprotection in rabbits is 10 min. When the ischemic period is longer than this, the IS after sustained ischemia is increased rather than restricted. However, the infarcted size in the 15-min PC group was not higher than that in the group subjected to 45-min continuous ischemia. This may be a major limitation for any clinical application of PC.

Attenuation of postischemic reperfusion injury is related to prevention of [Ca2+]m overload in rat hearts

Intracellular calcium overload has been implicated in postischemic reperfusion injury. In myocytes, mitochondrial free calcium concentration ([Ca2+]m), not cytosolic free calcium concentration ([Ca2+]c), overload is related to reoxygenation injury. We tested the hypothesis that [Ca2+]m, not [Ca2+]c, overload is an important mediator of reperfusion injury in whole hearts. [Ca2+]m and [Ca2+]c were assessed using indo 1 fluorescence in isolated rat hearts subjected to 45 min of ischemia and 20 min of reperfusion. Ruthenium red (RR), a selective inhibitor of mitochondrial calcium uptake at 0.025 microM, attenuated the increase of [Ca2+]m (4% RR vs. 57% control) over preischemic levels (230 +/- 10 nM) but did not affect the increase of systolic [Ca2+]c (990 +/- 100 nM RR vs. 1,010 +/- 130 nM control). This was associated with improved recovery of left ventricular developed pressure (61% RR vs. 37% control) and attenuation of the increase of diastolic pressure (34 mmHg RR vs. 47 mmHg control). Contractile recovery was related to the degree of [Ca2+]m overload in both control and RR hearts (r2 = 0.47, P = 0.001). This study is the first to demonstrate that [Ca2+]m, and not [Ca2+]c, overload is related to reperfusion injury in intact beating hearts.

Cytosolic and mitochondrial [Ca2+] in whole hearts using indo-1 acetoxymethyl ester: effects of high extracellular Ca2+

Assessment of free cytosolic [Ca2+] ([Ca2+]c) using the acetoxymethyl ester (AM) form of indo-1 may be compromised by loading of indo-1 into noncytosolic compartments, primarily mitochondria. To determine the fraction of noncytosolic fluorescence in whole hearts loaded with indo-1 AM, Mn2+ was used to quench cytosolic fluorescence. Residual (i.e., noncytosolic) fluorescence was subtracted from the total fluorescence before calculating [Ca2+]c. Noncytosolic fluorescence was used to estimate mitochondrial [Ca2+]. In hearts paced at 5 Hz (N = 17), noncytosolic fluorescence was 0.61 +/- 0.06 and 0.56 +/- 0.07 of total fluorescence at lambda 385 and lambda 456, respectively. After taking into account noncytosolic fluorescence, systolic and diastolic [Ca2+]c was 673 +/- 72 and 132 +/- 9 nM, respectively, noncytosolic [Ca2+] was 183 +/- 36 nM and increased to 272 +/- 12 when extracellular Ca2+ was increased from 2 to 6 mM. This increase in noncytosolic [Ca2+] was inhibited by ruthenium red, a blocker of Ca2+ uptake by mitochondria. We conclude that cytosolic and mitochondrial [Ca2+] can be determined in whole hearts loaded with indo-1 AM by using Mn2+ to quench cytosolic fluorescence.

Transient adenosine infusion before ischemia and reperfusion protects against metabolic damage in pig hearts

We investigated whether transient adenosine (Ado) infusion before ischemia had the same effect on myocardial metabolism and function as ischemic preconditioning (IP). The control (C) group underwent 15 min of coronary artery occlusion followed by 120 min of reperfusion. The Ado group received a 15-min infusion of Ado (200 micrograms.kg-1.min-1) into the left atrium starting 20 min before ischemia. IP was elicited by two cycles of 5-min ischemia and 5-min reperfusion. In the area at risk, tissue levels of ATP, creatine phosphate (CP), and intracellular pH (pHi) were serially measured by 31P-nuclear magnetic resonance spectroscopy in 10 pigs from each group, and percent segment shortening (%SS) was measured in 7 pigs from each group. ATP and pHi were preserved after 15 min of ischemia in both Ado and IP groups [ATP = 64 +/- 7, 76 +/- 6, and 74 +/- 9% of baseline; pHi = 6.35 +/- 0.19, 6.54 +/- 0.11, and 6.64 +/- 0.11 in C, Ado, and IP groups, respectively (P < 0.05, Ado and IP vs. C)]. During reperfusion, ATP was restored progressively in both groups [71 +/- 7, 90 +/- 8, and 91 +/- 9% of baseline at 120 min of reperfusion in C, Ado, and IP groups, respectively (P < 0.05, Ado and IP vs. C)]. However, in contrast to the IP group, CP was not preserved during 15-min ischemia nor did it show persistent overshoot during reperfusion in the Ado group. There were no significant differences in %SS during ischemia and reperfusion among the three groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Ischemic preconditioning elevates cardiac stress protein but does not limit infarct size 24 or 48 h later in rabbits

We investigated whether ischemic preconditioning (PC) produced a second window of protection by delayed synthesis of cardioprotective proteins. Anesthetized open-chest rabbits were subjected to 30 min of coronary occlusion and 3 h of reperfusion. PC was elicited by 5 min of ischemia and was separated from sustained ischemia by 5 min, 2 h, or 24 h of reperfusion. Infarct size (% area at risk) was markedly limited by PC with 5 min of reperfusion when compared with controls (13.3 +/- 2.5 vs. 46.8 +/- 7.0%; P < 0.05). This protective effect was lost when the interval between PC and sustained ischemia was extended to 2 h (47.8 +/- 4.8%; P = NS vs. control) and did not reoccur even when it was extended to 24 h (44.2 +/- 6.5%; P = NS vs. sham-operated control). To potentiate induction of heat shock proteins (HSPs), a PC protocol involving four 5-min episodes of ischemia and reperfusion was also used and was separated from sustained ischemia by 24 or 48 h of reperfusion. However, neither of these protocols was protective, and limitation of infarct size was not observed (55.5 +/- 5.9 and 53.4 +/- 6.5% in 24 and 48 h of reperfusion, respectively; P = NS vs. corresponding sham-operated control). Myocardial expression of HSPs was examined using a monoclonal antibody against 72- to 73-kDa HSP in additional rabbits. Immunoreactivity was observed in the myocardium at 24 and 48 h after PC, but not immediately after PC.(ABSTRACT TRUNCATED AT 250 WORDS)

Dropout of young non-insulin-dependent diabetics from diabetic care

We investigated the follow-up status and prognosis of 109 patients with non-insulin-dependent diabetes mellitus aged from 10 to 19 years old (66 males and 43 females). Patients who had not attended hospital for at least 20 months up to the end of September 1990 were regarded as defaulters, and were surveyed by questionnaire. There were 62 defaulters (56.9%) among the 109 patients originally enrolled in diabetes care. The defaulters had a significantly higher body mass index (both males and females), mean arterial blood pressure, and fasting blood glucose level than the patients still attending the diabetes clinic, as well as a significantly worse lipid profile. The main reason given for non-attendance was a busy schedule. Compared with patients attending the diabetes clinic, a lower percentage of the defaulters remained on a diet or took regular exercise. Rapid eating was more common among the defaulters than the attendees (92.9% vs. 60%, P = n.s.). Thus, the lifestyle of the defaulters seemed to be undesirable for young diabetic patients. These findings emphasize the importance of effective education and follow-up for young obese patients with non-insulin-dependent diabetes mellitus.

Ventricular expression of brain natriuretic peptide in hypertrophic cardiomyopathy

BACKGROUND

Brain natriuretic peptide (BNP), as a cardiac hormone, is expressed together with atrial natriuretic peptide (ANP) in the ventricles in congestive heart failure. However, the ventricular expression of BNP in hypertrophic cardiomyopathy (HCM) with normal systolic function is still unclear.

METHODS AND RESULTS

The study population consisted of 39 HCM patients with asymmetric septal hypertrophy and 10 control subjects without any specific cardiac disease. Eleven cases of HCM were obstructive (HOCM), and the other 28 cases were nonobstructive (HNCM). All of these patients had a normal ejection fraction. Immunohistochemical analysis of endomyocardial biopsy specimens with specific monoclonal antibodies showed BNP immunoreactivity in the HOCM group (5/10, 50%) but not in the HNCM group (0/22) or in control subjects (0/5). In HOCM, left ventricular end-diastolic pressure was significantly higher in the BNP-positive patients than the BNP-negative patients. Histological changes such as myocardial fiber disarray, hypertrophy of myocytes, and fibrosis were greater in BNP-positive patients than BNP-negative patients in HCM. However, the expression had no significant relation with other clinical parameters. The elevation of the BNP plasma level versus control subjects was marked in both HOCM (85-fold) and HNCM (23-fold). By contrast, the elevation of the ANP plasma level versus control subjects was mild in HOCM (5.7-fold) and HNCM (4.2-fold). The ratio of BNP level to ANP level was higher in HOCM (4.16) than in HNCM (1.46) and control subjects (0.28), and it was higher than the ratio previously reported for severe congestive heart failure (1.72).

CONCLUSIONS

These findings suggest that BNP is expressed in the ventricular myocytes of HCM with normal systolic function. In HOCM, ventricular expression of BNP may be augmented in response to both obstruction and diastolic dysfunction.

Dobutamine prevents both myocardial stunning and phosphocreatine overshoot without affecting ATP level

Catecholamines can overcome myocardial stunning. However, a previous report on energy metabolism in stunned myocardium during catecholamine infusion was based on the conventional biochemical methods which might affect contractile function. Twenty farm pigs were anesthetized and underwent 15 min coronary artery occlusion and 2 h reperfusion. Ten pigs were given 10 micrograms/kg/min dobutamine from immediately after and throughout the reperfusion (dobutamine group). The other ten pigs were given saline (control group). Phosphorus-31 magnetic resonance spectroscopy and sonomicrometry were done alternately. Dobutamine improved percent segment shortening after reperfusion (control/dobutamine = 3.8%-5.7%/11.7%-13.4%; P < 0.01). At 15 min ischemia, adenosine triphosphate (ATP) decreased (control/dobutamine = 72 +/- 8%/73 +/- 10%, n.s.), and remained depressed after reperfusion in both groups. After reperfusion, phosphocreatine (PCr) returned to and maintained the preischemic value in the dobutamine group, while in the control group, PCr overshoot (112 +/- 5%) was observed. Except for the presence and absence of PCr overshoot, there was no significant difference of ATP and PCr between the two groups, although rate pressure product was significantly higher in the dobutamine group than in the control group. Regional myocardial blood flow after reperfusion was significantly higher in the dobutamine group. Dobutamine may improve "stunning" through effective improvement of energy utilization and production, indicated by the disappearance of PCr overshoot and maintained ATP level.

Preconditioning improves energy metabolism during reperfusion but does not attenuate myocardial stunning in porcine hearts

BACKGROUND

It has been reported that a brief period of coronary occlusion and reperfusion slows the rate of ATP depletion during subsequent sustained ischemia as well as limiting infarct size. However, it has not yet been determined whether ischemic preconditioning also has an effect on the functional and metabolic recovery of stunned myocardium. Our study was designed to address this problem.

METHODS AND RESULTS

Farm pigs were anesthetized with fluothane and randomly assigned to either a control group or a preconditioned group. The control group (n = 15) underwent 15 minutes of coronary occlusion followed by 120 minutes of reperfusion. The preconditioned group (n = 14) underwent two episodes of 5-minute occlusion and 5-minute reperfusion followed by 15 minutes of occlusion and 120 minutes of reperfusion. This protocol was designed to exclude the stunning effect of the preconditioning procedure itself as much as possible besides preconditioning the heart. A pair of ultrasonic crystals was implanted in the area at risk perfused by the left anterior descending coronary artery. 31P-nuclear magnetic resonance spectroscopy and sonomicrometry were performed alternately. Regional myocardial blood flow (RMBF) was determined with colored microspheres. At 15 minutes of sustained ischemia, phosphocreatine (Pcr), ATP, and intracellular pH were significantly better preserved in the preconditioned group (Pcr: control/preconditioned, 1 +/- 1%/14 +/- 1%; ATP:control/preconditioned, 66 +/- 2%/74 +/- 2%; pH:control/preconditioned, 6.32 +/- 0.07/6.52 +/- 0.05; P < .05). After reperfusion, ATP increased progressively and was almost normalized at 120 minutes of reperfusion in the preconditioned group (control/preconditioned, 73 +/- 4%/95 +/- 3%; P < .05). Overshoot of Pcr (which indicates that the energy generating system is operating better than energy utilizing system) persisted in preconditioned hearts but disappeared rapidly in controls (control/preconditioned, 104 +/- 3%/130 +/- 3% after 120 minutes of reperfusion). There was no significant difference in percent segment shortening (%SS), RMBF, and hemodynamics between the two groups throughout the experiment (%SS: control/preconditioned, 29.8 +/- 5.9%/28.8 +/- 6.3% of baseline after 120 minutes of reperfusion).

CONCLUSIONS

Preconditioning improves energy metabolism during reperfusion, although it does not attenuate myocardial stunning for at least 2 hours after reperfusion.

Histologic studies in percutaneous transluminal coronary angioplasty for chronic total occlusion: comparison of tapering and abrupt types of occlusion and short and long occluded segments

OBJECTIVES

The purpose of this study was to examine the histologic-angiographic correlates of chronic total coronary occlusion and to explain why a tapering type of occlusion and short occluded segments are favorable for percutaneous transluminal coronary angioplasty.

BACKGROUND

Coronary angioplasty is less successful for vessels with chronic total occlusion than for highly stenotic but patent vessels. Several clinical and angiographic factors determining the rate of initial success have been investigated, but the underlying histologic features are not clear.

METHODS

Ten autopsy hearts that showed chronic total coronary occlusion on cineangiography performed < or = 3 months before death were selected. In all, the estimated duration of occlusion was > 1 year. At autopsy, postmortem angiography was performed and hearts were fixed with 10% buffered formalin. Occluded segments were sectioned transversely and serially into slices 10 microns thick. Every five slices were stained in hematoxylin-eosin and elastic van-Gieson.

RESULTS

Ten hearts with chronic total coronary occlusion were angiographically classified into five with a tapering and five with an abrupt type of occlusion and seven with a short (< or = 15 mm) and three with a long (> 15 mm) occluded segment. Histologically, the occluded segment was composed of loose or dense fibrous tissue, atheroma, small vascular channels and calcified tissue. Reconstruction of the serial preparations showed that small lumen recanalized areas (diameter 160 to 230 microns) with surrounding loose fibrous tissue penetrated the occluded segment in four hearts with occlusion of the tapering type and a short occluded segment. In these four cases, the lack of anterograde flow on cineangiography could be explained by the presence of rich collateral flow. In three cases of the abrupt type of occlusion with a short occluded segment, a mass of loose fibrous tissue penetrated the occluded segment. In hearts with a long occluded segment (one with a tapering type of occlusion and two with an abrupt type), there was no recanalization and loose fibrous tissue was dispersed in the occluded segment.

CONCLUSIONS

Chronic total coronary occlusion of the tapering type or with a short occluded segment, or both, is possibly favorable for angioplasty, because small lumen recanalized areas or loose fibrous tissue penetrates the occluded segment and may form a route for successful angioplasty.

Adhesive strength between teeth and resin cements for porcelain laminate veneer

We performed an experiment on adhesive strength between teeth and resin cements for porcelain laminate veneer. A compression shear test was performed using three types of resin cement in extracted human anterior teeth. In dentin, the effects of various surface treatment methods were also evaluated. All three types of resin cement showed high adhesive strengths to enamel, but low adhesive strengths to dentin that were less than 1/2 of those to enamel. Treatment of the dentin surface with both a surface treatment agent and primer significantly increased adhesive strength.