ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

The relationship between flow and pressure was studied in the perfused hindquarters of the rat. The conclusion is drawn that peripheral resistance declines progressively with increasing intravascular pressure at various rates of flow, regardless of whether the vessels are relaxed or constricted.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

This is a theoretic investigation of the influence of the position of a current dipole on the electric potential produced at the boundary of a homogeneous conducting sphere. Thirty different eccentric dipole positions are selected within the sphere to bear analogy to locations of the equivalent dipole of the human heart within the chest, and boundary-potential calculations are made from points selected to bear analogy with body-surface points utilized in limb leads, Wilson centralterminal and frontal-plane electrocardiography. The point of view taken differs completely from the scalene-triangle geometric representation of eccentricity; instead, an equilateral triangle is used in conjunction with assigned strength and orientation time-variations for the eccentric dipole.It is concluded that if electrocardiography were subject to no other limitation of the application of field analysis, eccentricity of dipole position alone can produce very significant deviations between the manifest heart vector and the true heart vector in both direction and magnitude. The dependence of the Wilson central-terminal voltage on dipole eccentricity is likewise appreciable and of the same order of magnitude as reported by several experimenters; however, the effects of eccentricity on the Wilson central-terminal voltage are generally less pronounced than on the manifest heart vector.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

This study of the effects of certain drugs, gas mixtures, and other stimuli on the cerebrospinal fluid pressure corroborates previous conclusions that alterations in cerebral blood flow are reflected by similar changes in the cerebrospinal fluid pressure in the same direction. The hypothesis is advanced that the elevations and depressions in cerebrospinal fluid pressure resulting from these agents are due to the respective increased and decreased volume of the vascular structures of the brain, expanding within its rigid container.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

Before the metabolic role of the blood plasma expander, polyvinylpyrrolidone (PVP) can be studied by the technic of ionography, some fundamental ionographic characteristics of the polymer, per se, must be determined. This study is concerned with the influence of such variable factors as time, potential gradient, temperature, the pH of the buffer and its ionic strength on the mobility of the migrant when under the influence of an electrical field, and an attempt has been made to correlate them. This work, then, may serve as a basis for later investigations to be made on the combining power of PVP for certain physiologic products with which it comes into intimate contact when used as a plasma expander.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

Physiologic higher frequency phenomena may be demonstrated in ballistocardiograms from normal subjects. These phenomena consist of notches or multiple oscillations on the H-I and K-L segments of the tracings. They may be demonstrated by recording the unfiltered output of an electromagnetic direct-body ballistocardiograph. They become more prominent as the transducer is applied closer to the source of cardiovascular forces, or by passing the output of the transducer through a band pass filter. The time relationship of these oscillations to simultaneously recorded heart sounds suggests their association with the ballistics of the closing heart valves.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

The azotemia of patients in diabetic coma is the result of impaired blood supply, unless tubular impairment antedates or supervenes. Clearance and blood pressure data are presented which strongly suggest that increased blood viscosity is the dominant reason for the reduced renal blood flow.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

Acute ligation of the portal vein in the barbital-anesthetized dog produces a significant increase in the hepatic arterial flow when the perfusion pressure remains elevated in the artery. Evidence is presented which supports the concept that the immediate readjustment is solely dependent on dynamic changes. The late readjustments are probably conditioned by the interplay of neurogenic and humoral factors.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

Trained standardized dogs were fasted until the blood pressure declined to the stable fasting level and were realimented with isocaloric diets high in protein (horse meat) or in carbohydrate (rice or cracker meal). Realimentation was at low maintenance or luxus consumption levels of caloric intake. At the former level, there was no difference between the diets, but at the latter level, the systolic blood pressure and pulse rate were higher on the carbohydrate diet, while the diastolic pressure was normal or low. Preliminary fasting was necessary to obtain a prolonged effect of the carbohydrate diet. Meat appears to antagonize carbohydrate.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID

摘要:

A scintillation counter permits the use of very low doses of I131-albumin in the recording of radiocardiograms. In the presence of mild heart failure there is a distinct widening of the interval between the humps derived from the right and left heart. Application of the principle of three-compartment serial dilution suggests that this prolongation may be due in large part to reduced cardiac output; however, cardiac dilatation may contribute significantly. Although radiocardiographic tracings represent time concentration curves, wide angle counting over the heart does not permit a reliable direct estimate of cardiac output. The chief source of error lies in the variable contribution of surrounding extracardiac tissue to the total activity which is recorded.

ISSN:0009-7330    

出版商:OVID    

年代:1953

数据来源: OVID