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Biomedical subjects

J Schmier

Publications and source records attributed to J Schmier.

62 records · Page 4Linked to original sources
PubMedDate not supplied

[Intramyocardial pressure at various depths, during aortic constriction and myocardial ischemia in the dog (author's transl)].

Systolic intramyocardial pressure (IMP) is measured with a modification of the "closed perfusion technic" in 3 different layers of the myocardium in 8 anesthetized mongrel dogs. In the subendocardium IMP exceed left ventricular pressure (LVP) by about 30% whereas it is 30% lower than LVP in the subepicardium. Under resting conditions the level of isobaric balance of IMP and LVP is at a distance of 57% from the epicardium. During thoracic aortic constriction the ratio of IMP/LVP increases in the subepicardium but decreases in the subendocardium. Occlusion of the left circumflex coronary artery for 30 seconds results in a decrease of IMP and IMP/LVP in the ischemic region. In 25% of all cases, however, an increase of these parameters is found.

Animals↗
PubMedDate not supplied

[Effects of coronary stenosis and mean aortic pressure on coronary blood flow, poststenotic coronary pressure, and reactive hyperemia].

Six dogs were subjected to an acute stenosis of the left anterior descending coronary artery. The mean aortic pressure was fixed with a windkessel and an occluder on four different levels. A significant decrease of coronary blood flow and poststenotic coronary pressure was closely related to the level of mean aortic pressure. With lower aortic pressure the decrease occurred earlier than with higher aortic pressure. A 50% stenosis did not significantly influence coronary flow and poststenotic coronary pressure. A 90% stenosis resulted in decrease below 10% of control. In a range of aortic pressure between 60 and 140 mm Hg reactive hyperemia was significantly diminished at a 60% stenosis. Reactive hyperemia was completely abolished when coronary stenosis was 90%.

Animals↗
PubMedDate not supplied

Hemorrhagic shock with fixed hypotension and with spontaneous recovery of blood pressure. A comparison of two shock models.

In 26 dogs anesthetized with a barbiturate peripheral blood flow, O2 consumption and acid-base balance have been studied in two kinds of hemorrhagic shock: 1. Hemorrhagic shock with fixed hypotension (hypotensive shock, n = 12) 2. Hemorrhagic shock with spontaneously recovering arterial blood pressure (normotensive shock, n = 14). In both groups the same amount of blood is withdrawn and stored in a reservoir (31-32 ml/kg) to reduce arterial pressure to 40 mm Hg. In hypotensive shock there is a continuous outflow of blood into the reservoir in order to maintain an arterial pressure of 40 mm Hg. After 1 1/2 hours this shift of blood reverses itself spontaneously. In normotensive shock the arterial pressure is allowed to increase after the initial withdrawal of blood. 1 1/2 hours later it reaches a peak of 93 mm Hg after which it starts declining again. The duration of oligemia which the animals control themselves is nearly identical in both groups (4 hours). Both kinds of hemorrhagic shock have a mortality rate of 80%. The survival time is shorter (p less than 0.01) in hypotensive (3 hours) than in normotensive shock (7 1/2 hours). In both kinds of shock heart rate increases to more than 200 beats/min. However, in hypotensive shock it decreases in the late stage of hypovolemia, whereas the increase is continuous in normotensive shock. Cardiac output is significantly higher in the normotensive animals nearly throughout the entire hypovolemic phase although the initial decrease is the same in both groups (71%). Also a greater increase in total peripheral resistance occurs in these animals. The increased cardiac output and total peripheral resistance. A "centralization" of the circulation is also observed in this kind of shock as is made evident by the changes in the relationship between cardiac output and carotid blood flow. Hyperventilation occurs in both kinds of shock. In hypotensive shock respiratory rate decreases at the end of the oligemic phase possibly due to a smaller cerebral blood flow.

Acidosis↗
PubMedDate not supplied

[Injection methods for the demonstration of the coronary arterial vasculature (author's transl)].

Four different methods for the demonstration of the coronary arterial vasculature are examined. Among the techniques studied corrosion casts (epoxid- and acrylic resin) permit the best qualitative and quantitative evaluation of superficial and deep arteries and arterioles. Down to the smallest infusible vessels of 15-25 mum there is practically no shrinkage. X-ray arteriography with an aqueous solution of barium sulphate is less suitable because X-rays allow no satisfactory stereoscopic view. The demonstration of arterioles and collaterals is limited to vessels larger than 50 mum because of the low resolution of the X-ray tube. Silicone rubber does not only fill the arteries, but also the capillary bed and the venous system. Therefore deeper parts of the vasculature can only be studied after slicing the heart. The substantial shrinkage of the material makes quantitative measurements difficult.

Animals↗
PubMedDate not supplied

Effects of moderate coronary stenosis on myocardial flow reserve in man and in the dog.

The influence of coronary stenosis on resting blood flow (201Tl-uptake) and myocardial flow reserve (bicycle ergometry) is studied in 18 patients with coronary disease. Severe coronary stenosis of 75--90% caused a reduced 201Tl-uptake both at rest and peak exercise. In contrast to this group patients with a 50--60% stenosis have a normal scintigram at rest but focal defects of 201Tl-uptake at peak exercise. Results are compared with experimental data obtained after acute coronary constriction and simultaneous coronary dilatation (myocardial flow reserve, MFR) in 12 dogs. 60% coronary constriction causes a 37% decrease of poststenotic MFR measured with tracer microspheres. Changes of transmural flow distribution (endo/epi ratio) are minor in the left ventricular free wall but significant in the poststenotic septum (endo/epi = .84). It is concluded that even a moderate coronary stenosis of 60% not affecting resting blood flow becomes "critical" under conditions of high flow velocities.

Adult↗
PubMedDate not supplied

The influence of the size of acute ischaemic myocardial lesions on coronary reserve and left ventricular function in the dog.

Acute ischaemic lesions of 5 and 15% of the left ventricular mass were produced in 10 dogs by ligations of branches of the left anterior descending coronary artery. Under maximal coronary dilatation by Dipyridamole and at constant aortic pressure, an ischaemic lesion of 15% caused reductions of blood flow in the left anterior descending coronary artery of 50% (p less than 0.05), , the R. circumflexus of 36% and of total myocardial blood flow (Argon method) by 44% (p less than 0.02). Parameters of left ventricular function, dp/dtmax and Vmax fell by 26 and 27% respectively (p less than 0.02). Ischaemic lesions of 5% LV mass were detected by 133 Xenon clearance estimations, but had no effect on any of the other variables measured. There was good agreement between estimations of total myocardial blood flow (Argon) and direct measurement of coronary flow with electromagnetic flowmeters (r = 0.957).

Acute Disease↗
PubMedDate not supplied

Health-related quality of life evaluations of gastric and pancreatic cancer.

This review addresses the state of the literature on health-related quality of life (HRQL) assessment among patients with cancers of the pancreas and stomach. We first briefly review the epidemiology of these cancers. We examine the concept of HRQL and the degree to which it has been measured among these patient groups. The impact of gastric and pancreatic cancers on HRQL is described, including the domains which these conditions are most likely to impact. The effect of different treatments on HRQL is considered, including surgical procedures, pharmacological and non-pharmacological therapies, and procedures for symptom palliation. Based on our findings on the limited quantity and quality of the body of literature, we make suggestions for further research in the area. Results suggest three areas in which HRQL can play an important role in the study of gastric and pancreatic cancer. First, future investigations should consider both survival and HRQL in comparing surgical procedures. Second, studies of chemotherapy should include HRQL evaluation, with careful attention to conducting assessments at times appropriate to capture the effects of chemotherapy. Third, studies of the impact of palliative care should include assessments of HRQL.

Humans↗