[A new thermodilution catheter for the determination of heart-minute volume in the arterial system]

A double-lumen polyethylene pigtail catheter (F8, length 100 cm) for the determination of cardiac output (CO) in the arterial system is described. Following femoral insertion of the catheter, 10 ml of ice-cold saline is injected into the left ventricle through the distally ending lumen (0.8 mm2). Through the second lumen (0.8 mm2) which opens 50 cm behind the catheter tip, a thermistor probe (F3, teflon) is advanced into the descending aorta for recording of thermodilution curves. In 21 patients CO was determined first by the Fick method and then by thermodilution in the arterial system. CO by thermodilution correlated favorably with CO by Fick (r = 0.92, SEE 518 ml = 11% of the mean value). There was no systematic deviation from the reference CO. A similarly good correlation existed between stroke volume (SV) by thermodilution and SV by Fick (r = 0.86 SEE 11 ml = 15% of the mean value). Heart rate during thermodilution was 71 bpm, during Fick output estimation 72 bpm (not significant). Following withdrawal of the thermistor probe, simultaneous measurements of left ventricular and aortic pressures can be performed.

Diastolic function in aortic valve disease: techniques of evaluation and pre-/postoperative changes

Passive diastolic properties of the left ventricle are determined by several factors intrinsic or extrinsic to the ventricle. In patients with myocardial hypertrophy due to longstanding pressure or volume overload increased muscle mass and structural alterations of the myocardium are responsible for changes in passive elastic properties. Evaluation of diastolic function includes determination of ventricular (= chamber) and myocardial (= muscle) stiffness from simultaneous pressure-volume and stress-strain relations during passive diastolic filling. The slope of the pressure-volume relationship is equal to the constant of chamber stiffness and the slope of the stress-strain relationship equal to the constant of myocardial stiffness. Passive diastolic properties were determined in ten control patients and 21 patients with aortic valve disease before and 17.5 months after successful valve replacement. Ten patients presented with severe aortic stenosis, five patients with combined valve lesions and six patients with severe aortic insufficiency. Simultaneous high-fidelity pressure measurements and M-mode echocardiography were carried out in all patients. Myocardial stiffness was calculated from a viscoelastic stress-strain relationship using a nonlinear curve-fit program. Standard hemodynamic measurements showed a significant decrease in pressure and volume overload after successful valve replacement. Left ventricular muscle mass index decreased in all three groups significantly after surgery, whereas systolic ejection fraction remained unchanged pre-/postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Diastolic stiffness and myocardial structure in aortic valve disease before and after valve replacement

Passive diastolic properties were determined in 10 control patients and 21 patients with aortic valve disease before and 17.5 months after successful valve replacement. Ten patients had severe aortic stenoses (AS), five had combined aortic valve lesions (AS + aortic insufficiency [AI]), and six patients had severe AI. Left ventricular endomyocardial biopsies were obtained before and after surgery in patients with AS, AS + AI, and AI. Simultaneous echocardiographic and high-fidelity pressure measurements were made in all patients, and left ventricular chamber stiffness was calculated from a viscoelastic pressure-circumference relationship and left ventricular myocardial stiffness from a viscoelastic stress-strain relationship. The constant of chamber stiffness, beta', was slightly although not significantly increased in patients with AS (0.27 before and 0.24 after surgery), but was normal in those with AS + AI (0.22 before and 0.17 after surgery) and slightly decreased in those with AI (0.18 before and 0.16 after surgery) when compared with in control subjects (0.21). The constant of myocardial stiffness beta was normal in patients with AS (13.2), AS + AI (11.5), and AI (11.7) before surgery compared with in the control group (12.5). beta increased, however, significantly in those with AS (25.2; p less than .02), but not in those with AS + AI (16.3; NS) and AI (12.8; NS) after surgery. Myocardial morphologic characteristics showed a significant decrease in muscle fiber diameter in patients with AS, AS + AI, and AI, as well as a significant increase in interstitial fibrosis from 15% to 26% (p less than .05) in those with AS and a slight increase from 15% to 22% (NS) in those with AS + AI and from 19% to 24% (NS) in those with AI. Left ventricular fibrous content (left ventricular muscle mass index multiplied by interstitial fibrosis) remained, however, unchanged in all three groups after aortic valve replacement. In conclusion, left ventricular chamber stiffness is increased in AS but decreased in AI, whereas LV myocardial stiffness is normal in patients with aortic valve disease before surgery. After surgery, left ventricular myocardial stiffness increased significantly in AS patients but remained unchanged in those with AI. Postoperative changes in myocardial structure were characterized by a decrease in muscle fiber diameter and a relative increase in interstitial fibrosis, whereas fibrous content remained unchanged. Thus, regression of myocardial hypertrophy in aortic valve disease is accompanied by an increase of myocardial stiffness in concentric hypertrophy that is not seen in eccentric hypertrophy.

[Relaxation and regional myocardial stiffness in obstructive hypertrophic cardiopathy patients: effect of verapamil]

Diastolic stiffness of the septum and the posterior wall were determined in 6 patients with hypertrophic obstructive cardiomyopathy before and 10 to 15 min after the intravenous administration of verapamil, 0,1 mg/kg. Left ventricular high-fidelity pressure measurements and M-mode echocardiography were carried out in all patients before and after verapamil. Diastolic stiffness of the septum (beta S) and of the posterior wall (beta) were assessed from the slope of a viscoelastic stress-strain relationship: sigma = alpha (e beta epsilon -1) + eta epsilon where sigma = meridional wall stress (g/cm2) alpha = intercept (g/cm2), beta = constant of myocardial stiffness, epsilon = mid-wall strain, eta = constant of myocardial viscosity (g. sec/cm2), epsilon = strain rate (sec-1). Left ventricular relaxation was evaluated from the time constant of left ventricular pressure fall (T; msec) by plotting left ventricular pressure versus dP/dt during the isovolumic relaxation period. Heart rate (71 versus 74 beats/min), left ventricular end-diastolic pressure (17 versus 17 mmHg) and peak systolic pressure (152 versus 146 mmHg) were not significantly different before and after intravenous administration of verapamil. The constant of myocardial wall stiffness of the septum (17 versus 16) and the posterior wall (15 versus 13) remained unchanged after verapamil, however, myocardial stiffness of the septum was slightly higher than myocardial stiffness of the posterior wall. The time constant of left ventricular pressure fall decreased significantly (P less than 0.05) from 53 to 43 msec following administration of verapamil. It is concluded that in patients with hypertrophic, obstructive cardiomyopathy, diastolic myocardial stiffness of the septum is slightly higher than the stiffness of the posterior wall. Verapamil does not influence the regional passive diastolic properties but has a beneficial effect on ventricular relaxation.

Diastolic function in hypertrophic cardiomyopathy: effects of propranolol and verapamil on diastolic stiffness

In patients with hypertrophic cardiomyopathy (HCM), impaired left ventricular (LV) relaxation and diastolic filling have been reported. Therefore, we determined LV diastolic stiffness in nine patients with HCM before and 10 to 15 min after 0.15 mg/kg propranolol i.v. (group 1) and in six patients with HCM before and 10 to 15 min after 0.1 mg/kg verapamil i.v. (group 2). Simultaneous LV cineangiography and high-fidelity pressure measurements were performed in group 1 and simultaneous M-mode echocardiography and high-fidelity pressure measurements in group 2. Passive LV chamber stiffness was determined in group 1 from the diastolic pressure-volume data using an exponential three-parameter model: P = ae beta V + C, where P = pressure, alpha = intercept, beta = constant of chamber stiffness, V = volume and C = baseline pressure. Passive LV myocardial stiffness was estimated in group 2 from the diastolic stress-strain data using a viscoelastic model: sigma = alpha' (e beta' epsilon -1) + eta epsilon, where sigma = meridional wall stress, alpha = intercept, beta' = constant of myocardial stiffness, epsilon = midwall strain, eta = constant of myocardial viscosity and epsilon = strain rate. LV relaxation was assessed from the time constant of LV pressure decay (T) by plotting LV pressure versus negative dP/dt. LV diastolic filling was evaluated from peak and mean LV filling rate in group 1 and from peak and mean midwall lengthening rate in group 2. LV chamber and myocardial stiffness, respectively, remained unchanged before and after administration of propranolol (beta = 0.054 and 0.047) and verapamil (beta' = 14.8 and 12.6); however, the time constant of LV pressure decay T increased significantly in group 1 from 45 to 66 ms (P less than 0.05) and decreased significantly in group 2 from 53 to 43 ms (P less than 0.05). Parallel to the changes in LV isovolumic relaxation, mean LV diastolic filling rate decreased significantly in group 1 from 257 to 196 ml m-2 s-1 (P less than 0.025) and mean LV midwall lengthening rate increased significantly in group 2 from 2.37 to 4.31 cm/sec (P less than 0.05). It is concluded that LV diastolic stiffness remains unchanged in patients with HCM after propranolol and verapamil. LV relaxation and mean diastolic filling, however, are impaired in patients with HCM following propranolol but are improved after verapamil. Thus, the beneficial effect of verapamil on diastolic mechanics is related to improved relaxation and diastolic filling rather than to changes in LV diastolic stiffness.

[Blood pressure, renin angiotensin aldosterone system and other cardiovascular risk factors in children of essential hypertensives (author's transl)]

In the present study, blood pressure, the renin angiotensin aldosterone system, and other cardiovascular risk factors, such as glucose, cholesterine, and triglycerides, were investigated in 294 offspring of essential hypertensives (5-34 years) and in 122 children of normotensive parents (5-34 years). Offspring of essential hypertensives showed statistically significant higher systolic and diastolic blood pressure values than those of normotensive parents (p less than 0.003, less than 0.005, respectively). Furthermore, in children of hypertensive parents a statistically significant higher body weight and body mass index than in controls could be observed (p less than 0.006, less than 0.001, respectively). With the exception of statistically significant, lower mean supine plasma aldosterone values (p less than 0.02) in children of hypertensive parents, no major differences between the two groups were seen in stimulated aldosterone, supine and stimulated plasma renin activity, and plasma cortisol. Furthermore, in the present study, 41 hypertensive parents, 65 (normotensive) spouses of hypertensives, and 47 (normotensive) parents of control children were investigated. As expected, hypertensive parents showed statistically significant higher blood pressure values than parents of control children and their spouses (p less than 0.001). Interestingly, hypertensive parents had not only a higher body mass index than control parents but also than their spouses (p less than 0.01 and less than 0.02, respectively). These findings support a genetic disposition as being the underlying cause of higher body weight in hypertensives and make it less probable that a higher food intake in hypertensive families is responsible for this phenomenon. The results of the present study indicate that early body weight control in children of hypertensive parents may be an important contribution to the prevention of hypertension.

[Weight reduction and blood pressure]

112 patients (78 hypertensives and 34 normotensives) received guidance from a specially trained dietitian on a low-calorie diet. During a mean control period of 10.8 months with a comparable number of visits in each group, the following results were observed: 51% (n = 40) of hypertensive patients achieved a significant weight reduction. In 28% (n = 22) antihypertensive medication was constant and in 23% (n = 18) this medication was reduced or withdrawn. 37% (n = 29) showed no significant changes in body weight or blood pressure and 12% (n = 9) dropped out. In 22 patients a weight reduction of 8.5 kg with a significant fall in blood pressure from 156/99 to 137/90 mm Hg was observed. In 18 hypertensives a weight reduction of 8.5 kg allowed reduction or withdrawal of antihypertensive medication with blood pressure remaining unchanged (139/91 vs. 135/90 mm Hg). Similar results were achieved in 34 normotensive obese patients: 59% (n = 20) had significant weight reduction, 32% (n = 11) no significant reduction in weight or blood pressure, and 9% (n = 3) dropped out. 20 patients with a reduction of 9 kg showed a significant fall in blood pressure from 132/84 to 123/80 mm Hg. The results demonstrate the favourable effect of weight reduction on blood pressure. The time-consuming nature of the frequent and intensive checks should, however, be borne in mind.

[Occurrence and clinical relevance of thrombocytosis]

Automated routine platelet counting in 18,602 patients revealed thrombocytosis (platelet count above 400,000/mm3) in 9% (n = 1602) of cases. In 32% of the patients with thrombocytosis an acute or chronic inflammatory process was found, 9% had a malignant tumor and 9% anemia. 6% were alcoholics and 6% had a myeloproliferative syndrome. Chronic gastrointestinal disease was found in 4% and postoperative thrombocytosis in 3% of cases. 32% of the thrombocytosis cases could not be classified under any of the known causes of this disorder. In 51% of the cases the platelet count ranged from 400,000 to 450,000/mm3. Primary thrombocythemia often produced clinical symptoms, whereas secondary thrombocytosis almost always was asymptomatic.

[The value of serum ferritin, serum iron and iron-binding capacity in the differential diagnosis of microcytic hypochromic anemia]

Ferritin, iron, total iron binding capacity and transferrin saturation were measured in the serum of 247 patients with microcytic hypochromic anemia. Differentiation into various categories of microcytic hypochromic anemia was based on clinical criteria and on the response to iron treatment. This produced 147 patients with iron deficiency anemia, 35 patients with anemia secondary to infection, 27 patients with anemia due to tumor and 38 patients with thalassemia. Analysis of the iron parameters revealed the reliability of both serum ferritin and transferrin saturation in distinguishing between the various forms of anemia. However, measurement of serum ferritin is slightly more reliable and much less expensive than determination of transferrin saturation.

[The left ventricular function in bicycle ergometric stress before and after aortocoronary bypass surgery]

Biplane left ventricular cineangiograms and pressure measurements were performed in 44 patients with coronary heart disease at rest and during submaximal or symptom-limited supine bicycle exercise before and 7 +/- 3 months after bypass surgery. Revascularization was complete in 12 (group 1) and incomplete in 32 patients (group II). Preoperative left ventricular ejection fraction (EF) was within normal limits at rest and declined during exercise in both groups (group I from 59 to 51%, p less than 0.01; group II from 61 to 48%, p less than 0.001). Postoperative EF at rest was nearly identical to preoperative EF in both groups and remained unchanged during exercise (group I from 65 to 63%; group II from 58 to 56%). Peak systolic pressure to end-systolic volume index ratio (LVSP/ESVI in mm Hg/ml . m-2) also decreased during exercise in both groups peroperatively (group I from 3.7 to 3.2 [n.s.]; group Ii from 3.4 to 2.6, p less than 0.005). Postoperative LVSP/ESVI at rest was again unchanged as compared to preoperative LVSP/ESVI. During exercise, however, it increased in both groups, reaching higher values in group I than in group II (5.1 vs. 3.7, p less than 0.05). Whereas both parameters indicate improvement of global left ventricular function following surgery, LVSP/ESVI also suggests more marked recovery of function in patients with complete revascularization than in those where revascularization is incomplete.

Risk:benefit considerations for the use of isoxsuprine in the treatment of premature labor

Seventy patients treated with isoxsuprine for premature labor were studied. In patients with intact membranes prolongation of pregnancy for more than 7 days occurred in 77% of women with 50% cervical effacement or less and 3 cm dilatation or less at the initiation of therapy, and in none with more than 50% effacement and more than 3 cm dilatation. Cervical effacement was the primary factor in determining success. Cord isoxsuprine concentrations averaged 90% of maternal concentrations at delivery. Maternal and cord isoxsuprine concentrations at delivery were inversely correlated with the drug-free interval before delivery. An interval of more than 5 hours was necessary to attain a cord concentration of less than 2 ng/ml, a level not associated with neonatal problems. Drug-free intervals of 2 hours or less usually resulted in cord isoxsuprine values of more than 10 ng/ml, levels that are associated with severe neonatal problems. Seventy-seven percent of infants with cord isoxsuprine concentrations of more than 2 ng/ml and 91% with values of more than 10 ng/ml were delivered of mothers with more than 3 cm dilatation or more than 50% effacement at the initiation or reinstitution of intravenous therapy. Most severe neonatal problems are preventable if patients are selected carefully.

Regulation of urea cycle enzymes in transplantable hepatomas and in the livers of tumor-bearing rats and humans

The levels of the five enzymes of the urea cycle were measured in normal 5-week-old rats, in a transplantable hepatoma, and in the livers of tumor-bearing rats (host livers). The levels of all five enzymes were much lower in the hepatoma, although there was no exact correlation of the decrease in levels. In host livers, the levels were higher than in the tumors, but lower than in normal liver. The levels of all five urea cycle enzymes were positively correlated with dietary protein content in normal livers, in hepatomas, and in host livers. In fact, the hepatomas showed the greatest changes in response to diet. On all diets, the levels in host liver remained below those in normal liver, indicating that the decreased level was probably not due to preferential utilization of nutrients by the tumor. The levels of urea cycle enzymes in normal liver were not altered by a single injection of glucocorticoid, glucagon, or dibutyryl cyclic adenosine 3':5'-monophosphate. By contrast, in hepatoma, the levels were usually significantly elevated by the same treatment. In addition, the levels in host livers were always significantly elevated and were usually above those in normal animals, whether the latter were hormone treated or not. Injection of plasma from tumor-bearing rats into normal animals produced a decrease in the levels of all five enzymes; if glucagon was injected together with the plasma, large increases in levels were observed. This result supports the concept of a humoral factor produced by the tumor which affects the levels and the inducibility of urea cycle enzymes in host livers. Autopsied human primary hepatomas also showed levels of urea cycle enzymes below those in normal livers with host livers having intermediate values. A cell line derived from a human hepatoma showed induction of arginase by glucocorticoid in culture; in this, it resembled a cell line of the rat hepatoma. Tyrosine aminotransferase in human hepatoma cells was not induced by glucocorticoid; in this, it differed from the rat hepatoma cells where induction of this enzyme was observed.

Left ventricular function during exercise before and after bypass surgery

Biplane left ventricular cineangiograms and pressure measurements were performed in 44 patients with coronary heart disease at rest and during submaximal or symptom-limited supine bicycle exercise before and 7 +/- 3 months after bypass surgery. Revascularization was complete in 12 (group I) and incomplete in 32 patients (group II). Preoperative left ventricular ejection fraction (EF) was within normal limits at rest and declined similarly during exercise in both groups (group I from 59 to 51%, p less than 0.01; group II from 61 to 48%, p less than 0.001). Postoperative EF at rest was nearly identical to preoperative EF in both groups (group I, 65%; group II, 58%) and remained unchanged during exercise (group I, 63%; group II, 56%). Peak systolic pressure to end-systolic volume index ratio (LVSP/ESVI in mm Hg/ml . m-2) also decreased during exercise in both groups preoperatively (group I from 3.7 to 3.2, NS; group II from 3.4 to 2.6, p less than 0.005). Postoperative LVSP/ESVI at rest was again unchanged as compared to preoperative LVSP/ESVI. During exercise, however, it increased in both groups reaching higher values in patients of group I than of group II (5.1 versus 3.7, p less than 0.05). Whereas both parameters indicate an improvement in global left ventricular function following surgery, LVSP/ESVI even suggests a more sizable recovery of function in patients with complete as compared to those with incomplete revascularization.

Isoxsuprine in the perinatal period. II. Relationships between neonatal symptoms, drug exposure, and drug concentration at the time of birth

Forty preterm infants with maternal isoxsuprine exposure less than 24 hours delivery and 40 matched control infants were studied prospectively to determine the acute neonatal effects of maternal ISX exposure. The cord ISX concentration correlated inversely with the drug-free interval before delivery (P < 0.001). Cord ISX concentrations > 10 mg/ml were seen only with intravenous maternal therapy and a drug-discontinuance to delivery interval of two hours or less. The plasma half-life of ISX in neonates ranged from 1.7 to 8 hours; gestationally younger infants required a longer time for drug clearance. Ileus was 13 times more common in the ISX group and was not directly related to the cord ISX concentration. The incidence of hypotension and hypocalcemia rose directly with the cord ISX concentration, reaching 89% and 100%, respectively, when the cord ISX level exceeded 10 ng/ml. The incidence of respiratory distress syndrome was low in the ISX infants with low cord drug values, but increased to that of the control group when the cord ISX concentration reached > 10 ng/ml.

Control of plasma aldosterone during chronic hemodialysis

To investigate the effect of chronic hemodialysis (CH) on adrenal aldosterone release plasma aldosterone (PA), plasma renin activity (PRA), plasma cortisol (PC) and the serum concentrations of potassium (K) and sodium (Na) were measured before and at monthly intervals up to 26 months after initiation of CH in 42 patients with terminal renal failure. Body weight (BW), systolic (BPs) and diastolic (BPd) blood pressure were determined simultaneously. With 2 exceptions PA, PRA and PC as well as BW, BPs and BPd showed no significant changes. Following month 2 K was always significantly higher than the starting value while significantly higher Na values were observed in 12 of 26 different test periods (P less than 0.05--less than 0.001). Correlation analysis between the various parameters determined in this study revealed in 16 of 26 different months a significant relationship between PA and PRA (P less than 0.05--less than 0.001) and as expected in 20 of 26 between BPs and BPd (P less than 0.05--less than 0.001). Only at times were punctual correlations seen between any of the remaining parameters. Our results demonstrate that the prime influence of the renin angiotensin system on PA remains unaltered during CH. We conclude that the observed punctual correlations between the various parameters determined in this study are random and do not reflect a true relationship.

[Prevalence of hypertension and borderline hypertension in students. Comparison with a non-student group]

A blood pressure detection program was conducted at the University of Zurich in June 1978. Three consecutive blood pressure measurements using random-zero mercury sphygmomanometers (n = 4) were performed in 1364 students and 440 other subjects by 8 different investigators. Height and body weight were also measured and used to calculate the body mass index (Quetelet index). Personal history, physical activity, smoking and dietary habits were analyzed with the aid of a questionnaire. In comparison to initially measured values, there was a statistically significant decrease in systolic and diastolic pressure readings as the trial proceeded (p less than 0.001). Based on the mean value of all three measurements, hypertension was observed in only 1.7% of the male and 0.9% of the female students. In the other subjects covered by the trial the comparable values were 7.9% in males and 4.5% in females. The true prevalence of hypertension (addition of those persons with normotensive blood pressure values and simultaneous antihypertensive therapy) was 1.9% in male and 1.1% in female students, whereas 12.0% of the male and 8.5% of the female non-students suffered from hypertension. The prevalence of border-line hypertension (mean value of all three tests) was 7.4% in male and 3.0% in female students. Corresponding values for the other subjects tested were 18.7% (males) and 11.6% (females).

[Immunoglobulins (IgG, secretory-IgA) and function of parotid gland in children with cystic fibrosis, with bronchial asthma, and with chronic bronchitis (author's transl)]

The immunoglobulins IgG and IgA (Secretory-IgA) were determined in connection with the parameters of secretion in parotid saliva. Children with cystic fibrosis, with bronchial asthma and with chronic bronchitis were compared. No significant differences were found for the groups of cystic fibrosis, of bronchial asthma, and of chronic bronchitis in comparison to a control group in relation to flow rate and protein content in parotid saliva. The comparison of the groups of diseases showed striking differences only with regard to the output of the gland after stimulation. The output of the gland per minute for IgG was decreased for patients with bronchial asthma as well as for patients with cystic fibrosis. No differences were found for the patients with chronic bronchitis and for the control group. Also the output of the gland for secretory-IgA was decreased after stimulation in the groups of disease: bronchial asthma and cystic fibrosis. The concentration of immunoglobulins in serum no correlation with the concentration of immunoglobulins in saliva neither for IgA nor for IgG. A high content of IgG in serum of patients with cystic fibrosis was observed. The mean values of IgA in serum of patients with chronic bronchitis were found to be significantly decreased.

[Study of systolic ventricular volume changes by means of current measurement of contrast media]

Systolic changes of left ventricular volume were estimated after left ventricular contrast injections in dogs by roentgen-videodensitometry with adjustable windows. Good correlations were found between densitometric volume changes and the integral of electromagnetic aortic flow, as measured every 20 msec (r greater than or equal to 0.95 in 118 of 124 systoles analyzed). Videodensitometry avoids the time consuming frame-to-frame analysis with the errors inherent in geometric assumptions in ventricular volume measurements.

Influence of serum and insulin on the accumulation of aminoisobutyrate by rat hepatoma cells

1. Cultured rat hepatoma cells accumulate 2-aminoisobutyrate to high concentrations by a transport mechanism probably of the A type mediation. 2. Transport is enhanced by the presence of serum. When cells are deprived of serum the rate of transport declines over a period of hours; conversely addition of serum leads over a period of hours to increase in transport activity. In the presence of serum the apparent Km for aminoisobutyrate uptake is about 8 mM. In cells deprived of serum the Km is much higher. 3. Addition of insulin produces both an immediate increase in the rate of aminoisobutyrate uptake and a time-dependent rise. 4. The presence of alanine diminished aminoisobutyrate uptake in a concentration-dependent fashion. Competition is seen both in the presence and absence of serum but not when cells are incubated at 4 degrees C. 5. Preincubation with alanine for 1 h also diminishes aminoisobutyrate uptake when the alanine is removed. Cells take a period of several hours to recover from the depression of transport induced by alanine. 6. Transport of aminoisobutyrate rapidly declines in the presence of cycloheximide. Actinomycin had no effect for at least 8 h.

The influence of insulin on various enzyme activities in human and rat hepatoma cells

1. Incubation of human and rat hepatoma cells with insulin (1 mU/10(6) cells) decreases their content of adenosine 3':5'-monophosphate by more than half after 1 h and by about a quarter after 4 h. 2. The activities of the ATP-metabolising enzymes, adenylate kinase and Mg2+-adenosine triphosphatase are significantly increased by insulin within 1 h and after 4 h. Activity of succinate dehydrogenase and lactic dehydrogenase showed no change at either time interval. 3. Insulin markedly stimulated glucose 6-phosphate dehydrogenase activity within 1 h but by 4 h the increase was less apparent. Glutamate dehydrogenase activity by contrast was not increased by 1 h but was elevated at 4 h.

[Proceedings: Quantification of mitral valve insufficiency by means of videodensitometric measurement of the amount of contrast media in angiocardiography]

A new indicator quantity principle is presented which permits estimation of the regurgitant fraction in mitral incompetence from left heart angiocardiography by videodensitometric measurement of contrast medium content in the left heart chambers. In 90 experiments on dogs, a linear correlation of r = 0.89 was established between simultaneous determinations of mitral regurgitation by videodensitometry and electromagnetic flow measurement. Since only 1 catheter is needed for the injection of contrast medium and concomitant aortic incompetence can be computed from the same videodensitograms, this method is considered to be of special interest in clinical heart catheterization.