Search

Simultaneous recording of carotid arterial pressure and relative displacement of alveolar socket walls in dogs indicates a direct relationship between hemodynamic force and alveolar wall displacement. The effect was enhanced by the administration of ephedrine and diminished by histamine. [ABSTRACT FROM AUTHOR]

The Eysenck Personality Inventory, the Middlesex Hospital questionnaire, and forearm blood-flow were used to measure aspects of psychological status in forty-one patients with the irritable bowel syndrome, who were compared in this respect with twenty-five matched psychoneurotic subjects and with a general population. The results show a positive association between psychoneurotic disorder and the irritable bowel syndrome. [ABSTRACT FROM PUBLISHER]

The reopened umbilical vein presents a convenient route of access to the portal circulation. Beside the various diagnostic and therapeutic procedures performed through the umbilical vein it presents also an unique direct approach for anatomical study and investigation of the portal vein system. By reopening of the ductus venosus Arantii attempt was made to reconstruct the embryonic portocaval shunt. Portal pressure measurements demonstrated its increase in 30 per cent of the patients with metastatic livers. Pharmacodynamic study showed that pitressin used conventionally for arrest of the bleeding from esophageal varices is an ineffective and dangerous drug. If used at all it should be infused continuously and in smaller doses. Vasopressors cause hypoxia and acidosis of the portal blood and their use in surgical patients is questionable. Transumbilical vein cholangiography is a new method and can substitute for the percutaneous transhepatic cholangiography which has a danger of hemoperitoneum and bile peritonitis. [ABSTRACT FROM AUTHOR]

Twenty three patients with cirrhosis and bleeding esophageal varices who underwent porta-caval shunts were divided into two groups according to the direction of flow in the collateral veins and the rate of appearance of radio-opaque dye in the liver at the time of angiography. There were 8 patients with hepato-petal and 15 with hepato-fugal flow. The pre-operative data were similar (but not identical) in the two groups. A small difference in operative mortality and long term survival was noted in favor of the patients with hepato-fugal flow but this difference was not significant statistically. A larger number of cases is required before a definite relationship can be established between the direction of portal collateral flow on angiography and the risk of porta-caval shunt operations. [ABSTRACT FROM AUTHOR]

, , 673-677. The haemodynamic effects of breathing 100% oxygen have been studied by right heart catheterization at rest and during bicycle exercise in nine male patients with coronary heart disease. Oxygen breathing produced no significant haemodynamic benefit during angina pectoris induced by physical exercise, although at rest a reduction in heart rate and cardiac index was evident. The favourable effects of 100% oxygen breathing described in pacing-induced angina pectoris cannot therefore be transferred to exercise-induced angina probably because the myocardial blood flow during the latter condition is hampered by an increased left ventricular end-diastolic pressure. [ABSTRACT FROM PUBLISHER]

An angiographic pathophysiologic correlation of hepatic arterial changes in cirrhosis is presented. The angiographic findings include: increased hepatic arterial blood flow and size of the hepatic artery, reflux on superior mesenteric artery injection into pancreaticoduodenal, gastroduodenal and hepatic and splenic arteries, hepatic parenchymal blush in advanced cirrhosis, and increased tortuosity of hepatic arterial branches. The functional and organic changes accounting for these angiographic findings in cirrhosis are discussed. [ABSTRACT FROM AUTHOR]

An improved method is presented for the determination of the intrahepatic shunted blood flow. D-Galactose-1-C14 and T-1824 dye were continuously infused at a constant rate into the pulmonary artery. Per cent intrahepatic shunt was calculated from the radioactivities and dye concentrations of the arterial and the hepatic venous blood. Per cent intrahepatic shunt of 4 controls and 2 patients with acute viral hepatitis was 8–18. Twelve patients with chronic hepatitis showed 6–29 per cent of intrahepatic shunt with an average of 20 per cent, and 16 patients with hepatic cirrhosis showed 23–60 per cent of shunt with an average of 35 per cent. Thus, per cent intrahepatic shunt increased slightly in chronic hepatitis and markedly in hepatic cirrhosis. The range of overlap of per cent intrahepatic shunt between hepatic cirrhosis and chronic hepatitis was narrower by the present continuous infusion method than by the previous rapid injection method. There were statistically significant correlations between the per cent intrahepatic shunt and the per cent of interstitial tissue and between the per cent intrahepatic shunt and the wedged hepatic venous pressure. [ABSTRACT FROM AUTHOR]

Discusses the usability of blood rheology as a tool in diagnosing cardiovascular diseases. Influence of the viscosity of whole blood on the flow of blood; Impact of the increase in blood viscosity on the development of ischaemia and tissue necrosis; Distinctive denominator characterizing vascular diseases.

Acute experiments concerning the effect of dihydroergotamine, Hydergin and placebo (saline) on the blood flow and the capillary, filtration and the capacitance vessels of the calf, as well as the blood pressure of the distal thigh were studied in normal adults by aid of plethysmography. Hydergin increased significantly the mean value of the resting blood flow with 43 per cent (P < 0.001) while dihydroergotamine did not influence the blood flow significantly. Hydergin produced a decrease of the capillary filtration rate with about 22 per cent possibly due to a decreased blood pressure in the thigh q P < 0.05). No significant effect of dihydroergotamine was found on the capillary filtration rate or on the distal blood pressure in the thigh. On the venous side no effect was observed after Hydergin. Dihydroergotamine provoked strong constrictor response of the capacitance vessels (P < 0.001) and a decrease in the capacity of pooling of blood in the calf (P < 0.0.5). [ABSTRACT FROM AUTHOR]

Idiopathic hypertrophic subaortic stenosis (IHSS), generally reported in the young and middle-aged, was found with unexpected frequency in older patients being evaluated for coronary disease. The possibility of coexisting IHSS is usually overlooked when coronary artery disease has been proven by coronary. arteriography. Because IHSS can mimic coronary artery disease the diagnosis is difficult and can only be proven by catheterization. Recognition of the two diseases is critical. The symptoms are similar and drugs used to treat coronary disease may aggravate the cardiac problem of IHSS during medical treatment, endanger successful termination of cardiopulmonary bypass, and cause post-operative heart failure and death in surgical patients undergoing bypass operations for coronary artery disease. Operative or post-op- erative management of coronary surgical patients with sympathomimetic amines, nitrates or digitalis, may cause unexplained fatalities if both conditions have not been recognized preoperatively. In this report, eight patients with concomitant coronary arterial stenosis and IHSS, diagnosed clinically as coronary artery disease and sent for pre-op- erative evaluation for possible revascularization procedures, are presented. Three patients successfully underwent coronary bypass operations with con- siderable amelioration of anginal complaints. Hemodynamic studies and the principles of operative and post-operative management have been discussed. [ABSTRACT FROM AUTHOR]

QK times (QKs, QKD and QKS-D) in eighty normal subjects of both sexes between 19 and 40 years old were studied. The values obtained were not statistically significantly different in males and females. QKs had a significant negative correlation with heart rate in both sexes. QKD and QKS-D had also significant negative correlation with heart rate in one of the sexes only. [ABSTRACT FROM AUTHOR]

Copyright of Pneumonologie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Presents a study which examined a family affected with the Noonan syndrome which consist of the pulmonary valvar stenosis, small stature, hypertelorism, mild mental retardation, ptosis, undescended testes, and skeletal malformations. Information on patients and methods; Results and discussion; Details of the histological findings; Implication of the direct male-to-male transmission of the Noonan syndrome in the family.

Presents a study which correlated the presence of exercise-related ventricular premature complexes with both ST-segment depression and coronary arteriographic and ventricular findings in patients evaluated for chest pain. Clinical significance of exercise-related ventricular premature complexes; Methods used in the study; Results.

Six healthy human subjects performed grinding and clenching of teeth, to assess if pain releasing and strenuous muscular exercise causes a decrease or total stop of the blood flow through the temporal muscles, as measured by 133Xenon clearance. The mean blood flow/volume of muscle tissue was 25.4 ml × min-1 × 1 -1 during rest, whereas the mean flow was 101.8 ml × min-1 × l-1 during grinding, and 62.9 ml × min-1 × l-1 during clenching. It is suggested that facial pains induced by strenuous exercise of the jaw muscles are not due to ischemia. On the contrary, the blood flow seems to increase about 300 % during grinding and about 150 % during clenching. [ABSTRACT FROM AUTHOR]

The utility of the range correction, in which each individual autonomic level or response measure is expressed in terms of estimates of that S's maximum and minimum level or response amplitude, was evaluated in terms of the apparent reduction in error variance indicated by larger or more significant treatment effects. The data analyzed were from an experiment in which 48 Ss received 12 painful shocks in each of four conditions of shock predictability. A reduction in error variance resulted from correcting, for individual differences in tonic range, measures of tonic SC (a replication of previous findings) and measures of tonic HR (a new finding). A reduction in error variance also resulted from dividing each SCR to shock by that S's largest SCR, i.e., by correcting phasic SCR measures for individual differences in range of SCR. No marked improvement resulted from a similar correction of phasic HRR data. [ABSTRACT FROM AUTHOR]

After preliminary threshold determination, each of 25 Ss was given 120 trials (24 blank, 96 signal) in a visual signal detection task, with signal presentation being recorded with S's EKG. There was no relationship between hit rate and phase of cardiac cycle whether assessed over four measured phases, or as the difference in hit rate for signals presented either in the P-wave or the QRS complex. Implications for theory are discussed. [ABSTRACT FROM AUTHOR]

To more fully explore the possibility of control of the autonomic nervous system (ANS) in the human S, this study investigated the effects of instructions and exteroceptive feedback on the control of spontaneous galvanic skin responsivity (GSR). Two sets of instructions ("Relax" and "Think") were alternately presented to Ss under four types of meter feedback: accurate, positive, negative, and control. In addition to GSR activity, respiration and cardiac rate were recorded. The results indicated that Se receiving accurate feedback were significantly better able to comply with the "Relax"-"Think" instructions; next most effective was positive feedback, while negative and control feedback were least effective. No within-subject relationships were found between control of spontaneous GSRs and respiration or cardiac activity. The results suggest that Se are responsive to the consequences of their antonomic behavior in much the same manner as they are responsive to the consequences of other learned behaviors. [ABSTRACT FROM AUTHOR]

The mechanisms of operant conditioning of cardiac function can be analyzed in terms of cardiodynamics, hemodynamics, neural regulations, and psychological regulations. These separate analyses help to suggest a number of experimental hypotheses. Analyses of data from early and late phases of conditioning show that performance at these two stages of training is different: Analyses of acquisition mechanisms must come from the early phase of training, however, analyses of control mechanisms should probably be derived from chronic studies. [ABSTRACT FROM AUTHOR]

Ss, high and low in awareness of heart functioning as determined by scores on the heart functioning items of the Autonomic Perception Questionnaire (APQ), were given 10 trials each on which they were to raise or lower theft heart rate (HR) using continuous proportional visual feedback. Low aware Ss successfully raised and lowered their HRs on command whereas high aware Ss were not able to make significant alterations in their hits. [ABSTRACT FROM AUTHOR]

This study was concerned with the effects of cardiac information and reinforcement on raising heart rate (HR). The experiment consisted of a 3 × 2 design with three types of cardiac information and two reinforcement conditions. The cardiac information given to Ss consisted of instructions to control an Internal response (no specific HR information), instructions to increase HR (specific HR information), or instructions to increase HR while hearing heart beats through earphones (augmented HR information). External reinforcement was given to one-half of these Ss, while the remaining Ss received no external reinforcement. Sixty female undergraduates were randomly assigned to one of these six experimental groups. Analyses of these data indicate that Ss in both the augmented and specific HR information groups were able to increase their HR. The no specific HR information groups showed no increases in KR, suggesting that awareness of the criterion response plays an important role in raising HR. No differences were found between the reinforcement conditions. [ABSTRACT FROM AUTHOR]

The present paper contrasts the relative efficacies of the traditional mean square or variance, and a time-series statistic, the mean square successive difference, as descriptors of cyclic heart rate variability. Estimates of fluctuation in the R-R interval during the prestimulus and cold pressor stimulus periods were obtained for two subject samples. The first sample was composed of individuals having bilateral differences in the diameter of their pupils, a condition known as anisocoria, while the pupils of the Ss in the second sample were of equal diameter. A group sinusoidal rhythm in the mean square successive difference of R-R interval variation was observed during the cold pressor stimulus for the anisocoric sample. However, the rhythm was obscured when the traditional mean square statistic was utilized to describe the same R-R interval variation. No rhythms were identified for the non-anisocoric sample. The mean square successive difference statistic would appear to provide a method for detecting cyclic autonomic variability patterns otherwise obscured by traditional analysis. [ABSTRACT FROM AUTHOR]

Every one of the 8 Ss in this experiment showed lower heart rate in anticipation of a temporally uncertain UCS than he did during anticipation of a temporally certain one. Vigilance for uncertainty removing cues during UCS uncertain trials was offered as an explanation for the reduced heart rate of this condition. Previous investigations showing acceleration in heart rate under conditions of UCS temporal uncertainty were criticized, particularly with respect to the adequacy of the cardiac baseline employed. One unexpected and unexplained finding of this study was that 7 out of 8 Ss rated shocks as more painful when the UCS was certain than when it was uncertain. [ABSTRACT FROM AUTHOR]

Fifty-four Ss were divided into three instructional groups. One group was instructed to increase their heart rate (HR) every time a signal was presented; a second group was told to decrease their HR; and a control group was not instructed to change their HR in any direction. Results indicate that Ss can increase or decrease their HR in the absence of externalized feedback. These HR changes do not appear to be mediated by respiration or skin resistance variations. In addition, Ss were divided into groups on the basis of their APQ scores. The group with middle APQ scores displayed more HR control in both directions than Ss with high or Iow APQ scores. The study was replicated with 42 Ss and results support the HR increase but not the HR decrease findings. [ABSTRACT FROM AUTHOR]

Reaction time, body movement, heart rate, and skin resistance of Mongoloid and "normal" control children were evaluated under baseline and distraction conditions. Relative to controls, Mongoloids demonstrated (1) slower reaction time under both conditions, (2) a reduced skin resistance response and fewer heart rate fluctuations during the baseline period, and (3) fewer skin resistance fluctuations during the distraction condition. Furthermore, skin resistance fluctuations were negatively correlated with reaction time, and heart rate fluctuations, although not significant, were in the same direction. These findings offer some support for the theoretical assertions of Lacey and Lacey (1958) that spontaneous activity is related to motor impulsivity, cortical activity, and general skeletal-motor functions. Body movement was negatively related to these measures of spontaneous activity and thus cannot be invoked as an explanation for the findings. [ABSTRACT FROM AUTHOR]

The purpose of this experiment was to evaluate two hypotheses concerning the basis of the association between performance on a simple reaction time (RT) task and the deceleration of heart rate found as the S responds. The RT task consisted of 96 trials in which the foreperiod was randomly varied between 2, 4, 8, and 16 sec. Two groups of 31 Ss each were used, with the cardiac response blocked pharmacologically in one group, in order to determine if the occurrence of the cardiac response facilitated performance through an afferent feedback mechanism. Two aspects of somatic activity, EMG bursts from chin muscles and eye movements and blinks, were also assessed in order to determine if the cardiac response and the associated behavioral facilitative effects were linked to a common mediating process involving cardiac deceleration and the inhibition of ongoing, task-irrelevant somatic activities. The latter hypothesis was consistently supported. Blocking the cardiac response did not significantly influence performance. However, a within-S analysis revealed a pronounced direct relationship between RT and the magnitude of the inhibition of somatic effects and the magnitude of the cardiac deceleration when the latter was not blocked pharmacologically. These data along with several other lines of evidence are considered to indicate that heart rate deceleration may not be significantly involved in an afferent mechanism but rather can be best understood as a peripheral manifestation of central processes. [ABSTRACT FROM AUTHOR]

The hypothesis suggested by Luria (1963) that infants with central nervous system damage fail to habituate to repeated stimulation was tested using an experimental group whose clinical course suggested a relatively high probability of CNS damage, a control group matched for age in weeks since conception, and a group of normal, fullterm infants. An auditory stimulus at 80 db SPL was presented for 3 sec at 20-sec intervals. Heart rate change averaged across time on Trials 1-5 and Trials 26-30 were compared. The hypothesis was not confirmed, since significant habituation was found on Trials 26-30 for all groups. However, latency of response was significantly longer in high-risk Ss. A developmental trend toward decreased latency of response with increasing gestational age was identified. [ABSTRACT FROM AUTHOR]

Two-second long square wave tones at frequencies of 125 and 1000 Hz and 75 db sound pressure were presented to six newborn infants. Mean heart rates were computed for the 10 sec prior to and the 10 sec following stimulus onset, i.e. the prestimulus and stimulus heart rate values respectively. LIV was shown to operate strongly only in the case of the 125 Hz stimulus. Even for this stimulus, LIV depended upon the state of the infant, showing an appropriate negative correlation between prestimulus and stimulus values in regular sleep and quiet wakefulness but a slightly positive correlation in irregular sleep. In randomly selected control periods, the first 5 sec served as prestimulus values and the second 5 sec as stimulus values. Regression coefficients for these control periods did not differ significantly from those during which the stimulus was actually present. In view of the special conditions required for its demonstration, the generality of Wilder's "law" seems to be seriously questioned. [ABSTRACT FROM AUTHOR]

The study was designed to test Lacey's suggestion that elevated heart rate and blood pressure could lead to decreased sensory sensitivity and that a reduction in heart rate and blood pressure may facilitate sensory sensitivity. A tone of five intensities encompassing the subject's intensity threshold was presented randomly 25 times under high and 25 times under low transient heart rate. The results indicated no differences in the number of correct detections under high and low heart rate and no interaction between heart rate level and tone intensity. It was concluded that low heart rate may well be a necessary condition for increased sensory sensitivity, but that it is not a sufficient condition. Discussion was directed to the range of possible HR changes and the possible requirements of the sensitivity mechanism. [ABSTRACT FROM AUTHOR]

The instrument described has a linear indication of beat-to-beat heart rate with an overall accuracy of ± 1 beat per minute. A linear output response over the range of 30 to 270 beats per minute is achieved with a square law discharge network. Input clipping and filter circuits permit reliable operation with moderately active subjects. Details of the circuit design and its performance are discussed. [ABSTRACT FROM AUTHOR]

The rise of interest in the physiological effects of social psychological processes as of April 1967, often leads to a need for some way of recording emotional reactions in a number of subjects simultaneously. The recordings can be read to measure heart rate, volume pulse, and skeletal movements. This article describes a set-up that has been used to make plethysmographic recordings for as many as 6 subjects simultaneously. The set-up includes 6 plethysmographs, various power supplies, 6 bridge circuits and an oscillograph recorder with direct current amplifiers.

The purpose of this study was to see if heart rate (HR) speeding could be operantly conditioned. Five experimental Ss and five yoked-control Ss "were studied. Experimental Ss were positively reinforced for speeding their HR on a beat-by-beat basis, whereas yoked-control Ss were reinforced in a pattern based on the performance of paired experimental Ss. The data showed that: all Ss learned to speed their HR; some yoked-controls responded with a pattern of response that included increased HR; and the techniques which Ss use to regulate their HR vary widely from one S to another. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to investigate physiological activity associated with original learning and overlearning of verbal materials (nonsense syllables). In Experiment 1, the physiological responses measured were heart rate (HR), palmar skin conductance (PSC), and galvanic skin responses (GSRs) during original learning, overlearning, and new learning. In Experiment 2, the same physiological responses were recorded but original learning was followed by two overlearning phases. The results showed that: there were decreases in all of the physiological measures with overlearning; there were increases in all of the measures with new learning; and further decreases in physiological activity occurred with "double overlearning." It was concluded that the drop in physiological activity which occurred with overlearnlng was due to an habituation of physiological responses when Ss were no longer required to assimilate novel materials and a reduction in apprehensiveness as the experiment progressed. [ABSTRACT FROM AUTHOR]

Five human Ss were presented with a high frequency tone on the emission of each short inter-heartbeat interval and a low frequency tone on the emission of each long inter-heartbeat interval. Under these conditions, all Ss learned within a short period of time to produce significantly lower heart rates in the presence of one visual stimulus than in the presence of another. On the basis of this finding, it is suggested that an important determinant of where a given response falls on the voluntary/involuntary continuum is the availability of specific feedback from the response in question. [ABSTRACT FROM AUTHOR]

Compares the merits of early versus late clamping of the umbilical cord. Effect on blood volume; Effect on incidence of icterus; Effect on hemodynamics.

Describes the effects of hydrogen ion concentration on cardiac performance in the newborn lamb under controlled hemodynamic conditions. Influence of the potential of hydrogen ions on the responsiveness of the ventricle to catecholamines; Effect of acidemia on left ventricular function; Impact of acidosis on inotropic response of the newborn heart to catecholamines.

By the radioactive, freely diffusible, inert gas 133Xenon we studied the cutaneous blood flow in 15 cases of fresh, untreated psoriasis and in 10 normal subjects. In normal skin and in uninvolved skin in psoriatics the blood flow proved to be approx. 6.5 ml/100 g tissue per mm, while in the psoriatic plaques it was twice this value, viz., about 12 ml/100 g tissue per mm. It is concluded (1) that the gross erythema, the slightly elevated skin temperature (by 1.5° C), and the microscopic evidence of vascular changes in psoriatic lesions are in fact based upon increased blood flow, (2) that, according to the results of the present technique, the cutaneous tissue of uninvolved skin in psoriatics does not have a greater blood flow than cutaneous tissue of controls, and (3) that the present method of determining the cutaneous blood flow following intracutaneous injection of 133Xenon, calculating from the first, rapidly falling slope of the flow curve, is well-suited for clinical use, as the measurement need not be done for more than 10-15 minutes in order to calculate the cutaneous blood flow during the traumatic phase immediately after the injection. [ABSTRACT FROM AUTHOR]

The article focuses on the cerebral haemodynamic factors in mentally retarded children. It examines nineteen mentally retarded children aged seven to eighteen years. Cerebral haemodynamics were estimated by a quantified averaging method of rheoencephalography (REG). Simultaneous EEG records were obtained and four psychological tests administered. The scores were compared with those of fourteen healthy children similarly tested. The retarded children showed a significant impairment in the REG measurements matching their poor quality EEGs and lower psychological test scores by contrast with those of the healthy children.

The coronary arteries are a system of elastic tubes with one end open to the aorta and with a high resistance at the other end. The basic pattern of coronary input flow is determined 1. by the primary inflow wave due to the aortic pressure pulsation and 2. by a secondary wave which is generated by the periodic obstruction of outflow at the peripheral resistance due to the contraction of the heart. By means of the simplified model of a homogeneous elastic tube, details and oscillations of the coronary flow pattern could be explained as due to reflection and superposition of these primary and secondary waves. Flowpatterns constructed by use of this model were compared with flow pulses recorded in anesthetized dogs in the left circumflex coronary artery with an electromagnetic flowmeter. A characteristic feature of the apparent input impedance of a coronary artery has been found experimentally and could be explained by the fact, that the myocardial contraction serves as an additional energy source within the coronary system. The possible usefulness and physiological importance of the application of analytical methods to the hemodynamics of the coronary arteries is discussed. [ABSTRACT FROM AUTHOR]

Measurements of skin conductivity using silver disc and multiplint electrodes have been described. Comparisons with skin temperature measurements using thermistor probes have been made, and a parallel between the two parameters demonstrated. A connection between skin conductivity and blood flow was suggested, and confirmed by the effects on conductivity of exercise and the intradermal injection of adrenaline and histamine under the electrode site. The implications of this are discussed and a possible role of such measurements in the clinic is mentioned. [ABSTRACT FROM AUTHOR]

A simple method for the study of epidermis in vitro is described. Thin strips of skin were taken with a Castroviejo Keratome and then divided into equal sections. These sections were then cultured for short periods of time with tritiated precursor compounds including thymidine, cytidine, proline and histidine. At the end of the culture the specimens were prepared either for autoradiography or for direct quantitative estimation of their incorporated activity so that the rates of DNA, RNA and protein synthesis could he determined. The method yielded consistent results, and duplicates were within approximately 20% of each other. The rate of incorporation is linear over the first 4 hr. of incubation; but, as degenerative changes occur, the rate of incorporation decreases. Using this method, normal skin homogenates were found to depress DNA synthesis in 17 of 25 experiments. The relationship of this inhibitory activity to the chalone hypothesis is discussed. In addition, the effect of methotrexate on epidermis was Investigated, both by examining normal skin slices in the presence of methotrexate added directly to the culture media and in other experiments by incubating skin slices from the skin of patients being treated with methotrexate. A decrease in DNA synthesis 5 days after the start of methotrexate treatment and coincident with clinical improvement was detected in patients starting methotrexate treatment. When methotrexate was added directly to the culture medium a paradoxical increase in thymidine incorporation was detected resulting from the dihydrofolate reductase block. [ABSTRACT FROM AUTHOR]

The speed with which blister formation occurred in normal subjects when suction was applied to the skin has been shown to be closely related to skin temperature. Experiments in which skin temperature was controlled at 37° C. but skin blood flow was altered did not show that alteration of blood flow per se has any effect on the speed of blister formation. Acceleration of suction blister formation with increase of skin temperature was noted to occur in specimens of skin completely devoid of any blood supply. [ABSTRACT FROM AUTHOR]

Barbiturate solutions were applied to skin after removal of the stratum corneum with Sellotape, and skin surface oxygen tension was measured polarographically. These produced a rise in surface oxygen tension of 30 50 mm. Hg. The rate at which surface oxygen tension fell following arterial occlusion gave a measure of the rate of skin oxygen utilization. This was reduced by a factor which could be as large as 8 after application of barbiturate solutions. It is shown that both epidermal anti derma! oxygen utilization rates are reduced, and their return to normal depends on skin blood flow. [ABSTRACT FROM AUTHOR]

The mechanism of livedo production and the clinical associations of the symptom are discussed. The network vascular pattern is potentially present in all normal skin. It may be unmasked by two different mechanisms : (i) Interference with the arterial blood supply. (ii) Stimuli, e.g. heat, which preferentially involve the peripheral parts of the vascular " cones " where blood flow is more sluggish. Livedo reticularis is only a physical sign and has many causes. Widespread symmetrical livedo is only rarely associated with systemic disease. Patchy asymmetrical livedo demands a most careful investigation for systemic disease and must include repeated platelet counts. Biopsy material should be obtained to the depth of the deep fascia to include the larger vessels. [ABSTRACT FROM AUTHOR]

The nails may be affected in various ways in association with impaired peripheral blood supply. The changes are described in detail, based on the clinical appearances in 41 patients with symptoms of impaired peripheral blood flow but referred on account of nail dystrophies during the past five years. Subclavian arteriograms were carried out on 13 patients. The report includes a brief review of the literature and a short account of the arteriographic method employed. [ABSTRACT FROM AUTHOR]

1. A method is described of studying the response of the skin capillaries to changes in temperature in a small area, while the general limb surface temperature remains constant. This method permits direct measurements and comparisons to be made. 2. Cases of erythrocyanosis have been demonstrated to have two vascular abnormalities: (i) Reduced akin blood flow compared with normal (previous work). (ii) Inability of skin blood vessels to constrict on exposure to cold. [ABSTRACT FROM AUTHOR]

The article presents information about the role of sodium in eeythrocyanisis ceurum publlaeum. Under conditions of maximum vasodilatation, the sodium clearance rate is significantly slower in erythrocyanotic patients than in a group of normal controls of similar age and sex. It may therefore be deduced that under these conditions the local blood flow rate is slower in cases of erythrocyanosis than in normal subjects. The article concludes that the skin circulation may be given a numerical index for a particular site under certain strictly controlled conditions.