[Statistical analysis of pathological factors influencing prognosis of colorectal carcinoma]

The pathological and follow-up data of 503 patients with colorectal carcinoma have been analysed to assess quantitatively prognostic values of 16 pathological factors and their sub-categories with aid of computer. Besides the routine procedure, Cox's proportional hazards model, Hayashi's quantification theory II, III, Akaike's information criteria, Kendall's rank correlation, relative risk, and linear trend test were used. Regardless of methods used, liver metastasis, peritoneal dissemination, lymph nodes metastasis, depth of penetration, venous and lymphatic invasion emerged as powerful prognostic variables. Most of the analyses indicated that venous invasion contained the largest amount of prognostic information including that of long-term survival. When venous invasion is graded not only by the number of veins involved but also by the depth of invasion, its prognostic capability was comparable with that of staging systems. The values of relative risks calculated for the factors' sub-category were more closely associated with prognosis than five-year survival rates or median survival rates, thus permitting detailed comparison of different categories. We conclude the modern statistical methods are indispensable tool for prognostic factor analysis.

Development of coronary collateral circulation in left circumflex Ameroid-occluded swine myocardium

Coronary collateral development was examined in 34 pigs after gradual occlusion of the left circumflex coronary artery (LCX) with an Ameroid constrictor. Collateral development was assessed by measurements of myocardial blood flow and regional myocardial function at rest and during exercise over a 16-wk period after placement of the constrictor. Coronary collateral development was adequate to prevent severe infarction and restore blood flow to the collateral-dependent LCX region within 3-7 wk. Infarction averaged 5.0 +/- 1.3% of the LCX region. Blood flows at rest were 1.05 +/- 0.14 and 1.13 +/- 0.15 ml.min-1.g-1 in the subendocardium of the collateral and control regions, respectively, 7 wk postoperatively. Concurrently, collateral vessel development supported normal myocardial function at rest as determined by systolic wall thickening in the LCX region. However, collateral development was limited, since blood flows during moderate and severe exercise were reduced in the LCX region compared with control and left anterior descending and right coronary regions. Blood flow ratios (collateral/control flow) during severe exercise 3 wk postoperatively were 0.23 +/- 0.03 and 0.57 +/- 0.05 in the subendocardium and subepicardium and were constant throughout the 16-wk period throughout the study. Myocardial function of the collateral region also was reduced during exercise and a 30-min recovery period. We suggest that this limited coronary collateral circulation, which develops in response to gradual coronary occlusion in swine, serves as a model for the human collateral circulation for the study of protocols to alter growth and development of coronary collateral vessels.

Functional significance of alpha-adrenergic receptors in mature coronary collateral circulation of dogs

There is little information on the functional significance of alpha-adrenergic receptors in the dog's coronary collateral circulation. Accordingly, we investigated the effects of infusion of either norepinephrine (NE) or B-HT 920 (BHT), an alpha 2-adrenergic agonist, on vascular resistance of coronary collaterals in chloralose-anesthetized dogs 2-3 mo after placement of an Ameroid constrictor around the left circumflex coronary (LCX) artery. To accomplish this, the vagotomized left ventricle was autoperfused through the left main coronary ostium using a servo-controlled constant-pressure pump. Pressures of the left anterior descending (LAD) and peripheral LCX arteries were measured, and regional blood flow in LAD and LCX regions were determined with radioactive microspheres before and during NE infusion in the unblocked condition, following beta-adrenergic and beta + alpha 1-adrenergic blockade with the use of propranolol and prazosin, respectively. The same parameters were also measured before and during BHT infusion following beta-adrenergic and beta + alpha 2-adrenergic blockade with the use of propranolol and idazoxan, respectively. In the unblocked condition, NE reduced LAD, LCX, and collateral resistance by 43, 50, and 31%, respectively. After beta-adrenergic blockade, NE increased LAD resistance (29%) but did not alter LCX or collateral resistance. The increase in LAD resistance was abolished following alpha 1-adrenergic blockade. BHT increased vascular resistance in LAD, LCX, and collateral circulations by 35, 29, and 45%, respectively. Selective alpha 2-adrenergic blockade significantly attenuated the vasoconstrictor response to BHT.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandins contribute to cardiovascular reflexes evoked by static muscular contraction

The purpose of this study was to determine the contribution of prostaglandins to the reflex cardiovascular responses induced by static contraction of the hind limb in cats, i.e., the exercise reflex. To accomplish this, the cardiovascular responses to hind limb contraction induced by electrical stimulation of spinal cord ventral roots L6-7 and S1 were compared before and after inhibition of prostaglandin synthesis (indomethacin, 2-6 mg/kg i.v., n = 5, or sodium meclofenamate, 2-6 mg/kg i.v., n = 5) or after injection of prostaglandin E2 into the hind limb arterial blood supply. Treatment with indomethacin attenuated the contraction-induced increase in mean arterial pressure and left ventricular dP/dt by 76% and 86%, respectively. Heart rate and average developed triceps surae muscle tension were unchanged. After administering sodium meclofenamate, the reflex response was attenuated to a similar degree. In the indomethacin-treated animals, injection of exogenous prostaglandin E2 (PGE2) partially restored the pressor and myocardial contractile responses. In 6 animals, treatment with exogenous PGE2 without prior inhibition of prostaglandin synthesis did not significantly augment the contraction-induced cardiovascular response. Using the radioactive microsphere technique, we measured skeletal muscle blood flow during contraction before and after treatment with indomethacin (n = 6) to determine if an indomethacin-induced alteration in blood flow could account for the attenuated contraction-induced cardiovascular response. Blood flow during static muscle contraction was not significantly altered by indomethacin. We conclude that prostaglandins contribute to the exercise reflex through an action on afferent nerve endings rather than through a regional vascular effect.

Significance of collateral circulation on peri-infarct zone: assessment with stress thallium-201 scintigraphy

To evaluate the significance of collateral circulation on peri-infarct zone, stress myocardial scintigraphy and contrast left ventriculography (LVG) were performed in 38 patients with recent myocardial infarction (MI). All patients had at least one completely occluded coronary artery corresponding to the infarct area. In patients with good collaterals, stress induced transient enlargement of the perfusion defect, however, in those with poor or no collaterals the enlargement did not occur (p less than 0.05). Wall motion abnormality on LVG was significantly milder in the former patients than in the latter (p less than 0.001). Transient enlargement of the perfusion defect after stress and milder left ventricular asynergy were more frequently observed in patients with anterior MI and good collaterals. These observations indicate that good collaterals may keep some myocardium in the peri-infarct zone viable.

Relations between collateral flow and tissue salvage in the risk area after acute coronary occlusion in dogs: a topographical analysis

Localization of salvaged tissue after occlusion of the left anterior descending coronary artery due to collateral blood flow within the risk area was examined in a canine model using differential autoradiography. 125I tracer microspheres were injected into the left anterior descending artery preocclusively to define the perfusion territory as a risk area. 99mTc labelled human serum albumin microspheres were injected into both the left main and right coronary arteries 48 h after ligation to determine the collateral flow area. Using a cryotome, 50 micron transverse sections of the whole heart were taken, and 125I and 99mTc autoradiograms were obtained independently. The same specimens were stained by the nitroblue-tetrazolium method to demarcate the intact and infarcted myocardium. The tracings of the infarct, risk and collateral areas were compared and measured by a plainmeter. The collateral blood flow was distributed to 86, 55 and 42% of the epi, mid- and endo-cardial portions of the risk area respectively (P less than 0.001 between the epi- and mid- or endo-cardium). Within the collateral area 88, 58 and 63% of the epi-, mid- and endo-cardial portions were free of myocardial necrosis (P less than 0.001 between the epi- and mid- or endo-cardium). There was a close linear relationship between the size of salvaged and collateral areas (r = 0.96, P less than 0.001). Thus, a topographical analysis of the tissue salvage inside the risk area demonstrated the indispensable role of collateral blood flow for maintaining tissue viability.

Selective hypercontraction caused by ergonovine in the canine coronary artery under conditions of induced atherosclerosis

The relationship between the hypercontractile response of the regional coronary artery to ergonovine and induced vascular change after endothelial denudation and a high-cholesterol diet was examined in dogs by arteriographic (in situ) and mechanographic (in vitro) methods. In 15 mongrel dogs, selective endothelial denudation of either the left circumflex coronary artery (LCX) or left anterior descending coronary artery (LAD) was repeated twice 1 month apart by means of coronary arterial catheterization. A high-cholesterol diet (20 g/day) was given thereafter for 3 (n = 15) and 6 (n = 8) months. Although there was no difference in the extent of coronary vasoconstriction between the LAD and LCX before or immediately after endothelial denudation, after intravenous administration of ergonovine a significant augmentation of coronary constriction along the denuded portion was noted arteriographically in the long-term phase (1 to 6 months). At the end of the study in vivo, isometric tension of the strips of the denuded and contralateral intact coronary arteries was measured during the cumulative addition of ergonovine, serotonin, or phenylephrine to the organ bath; agonist responses were standardized by the response to 35 mM KCl. Although the concentration-response relations for phenylephrine (10(-9) M to 10(-5) M) were not significantly different between intact and denuded arteries, responses of the denuded portion to cumulative addition of ergonovine (10(-10) M) or serotonin 10(-9) M to 10(-5) M) exhibited markedly depressed threshold concentrations along with a significantly lowered negative logarithm (pD2) of the dose producing 50% of the maximum effect. The tension developed in the denuded portion was also enhanced over that noted in the contralateral coronary artery during the cumulative addition of ergonovine but not during application of phenylephrine. Thus enhanced constriction documented arteriographically may be derived from the localized hypersensitivity to ergonovine. Microscopically, the endothelial denudation and a long-term high-cholesterol diet resulted in a regional intimal thickening with fibrous proliferation but little lipid deposition. Therefore smooth muscle in atherosclerotic arteries may be hypersensitive to specific agonists such as ergonovine and serotonin in a canine preparation. These results suggest that coronary spasm induced by ergonovine in humans is relevant to the presence of atherosclerotic changes in the vascular wall.

Differential registration of two types of radionuclides on macroautoradiograms for studying coronary circulation: concise communication

Double-radionuclide autoradiography proved to be feasible using combinations of Tc-99m and I-125, or Tc-99m and C-14. Because of the short half-life of Tc-99m (6 hr), we first registered Tc-99m on x-ray film. Given an adequate Tc-99m:I-125 activity ratio of 20:1, the exposure duration for Tc-99m was still too short for I-125 to blacken the x-ray film. The pure emission from C-14 is completely absorbed by a thin aluminum sheet--hence no problem there. After the decay of Tc-99m, therefore, it was entirely feasible to continue autoradiography with I-125 (T1/2 = 60.2 days) or C-14 (T1/2 = 5730 yr). Based on these conditions, we applied (a) tracer microspheres labeled with I-125 and Tc-99m to define the respective perfusion areas of the left anterior descending, septal, and left circumflex coronary arteries of the beating heart, and (b) Tc-99m pyrophosphate and C-14 antipyrine to demarcate respectively the localization of the infarct-avid substance and the regional blood flow. We verified the first procedure with postmortem angiography and the second with histochemistry.

Two-dimensional echocardiographic demonstration of so-called aneurysm of the membranous ventricular septum in adults--value of combined "manual scanning"

Using two-dimensional (2-D) echocardiography we evaluated the applicability of the left ventricular (LV) short axis view combined with manual scanning technique for the detection and evaluation of aneurysms of the membranous ventricular septum (AMS). In 12 patients with angiographically proven AMS, we recorded from the left sternal border the short axis view of the left ventricle continuously displayed from the aortic to the ventricular level by tilting the transducer manually along the LV long axis plane. We then compared the detectability of AMS by this method with that by other standard fixed 2-D echocardiographic views. This method proved to be best for the detection of AMS (12/12), followed by an apical four-chamber view (10/12), a parasternal LV long axis view (8/12) and an apical two-chamber (2/12) view. For the detection of AMS and for three-dimensional evaluation of the structure of the AMS and the original orifice of ventricular septal defect the method was shown to be clinically applicable.

Angiographic evaluation of the coronary vasodilating effect of trapidil in anesthetized closed-chest dogs

We studied the effect of trapidil on coronary diameters of anesthetized closed-chest dogs using coronary angiography. Trapidil 2 mg/kg i.v. significantly (p less than 0.01) increased the diameter of the proximal (1.96 +/- 0.08 mm), middle (1.29 +/- 0.05 mm), and distal (0.86 +/- 0.03 mm) coronary arteries by 4.2 +/- 1.0, 7.6 +/- 1.2, and 10.8 +/- 2.2%, respectively. Nitroglycerin 20 micrograms/kg i.v. significantly (p less than 0.01) increased the diameter of classes I, II, and III arteries by 4.0 +/- 0.7, 7.7 +/- 1.3, and 7.5 +/- 1.8%, respectively. Ergonovine (0.4 mg i.v.; n = 13) reduced (p less than 0.01) the diameter of all three classes of coronary arteries by 8.2 +/- 1.2, 9.0 +/- 1.0, and 13.3 +/- 1.9%. After pretreatment with ergonovine, trapidil (n = 8) relaxed the coronary arteries from -10.4 +/- 1.7 to -2.4 +/- 1.7% constriction (p less than 0.05). These results indicate that in dogs trapidil dilates coronary arteries in a fashion similar to nitroglycerin and reverses ergonovine-induced coronary vasoconstriction.