Unreliability of M-mode left ventricular dimensions for calculating stroke volume and cardiac output in patients without heart disease

Single-dimension left ventricular echocardiographic measurements are currently being used in investigational studies as the basis for evaluating cardiac output parameters in normal subjects, even though validity of the method for normal subjects has not been established. We prospectively compared stroke volume derived from M mode left ventricular dimensions (LVID) to Fick stroke volume in 20 patients with no objective evidence of cardiac disease. Based on simultaneous studies, stroke volume by Fick ranged from 39 to 121 ml and cardiac output ranged from 3.9 to 10.4 L/min. Comparing the LVID cubed method with Fick, the correlation coefficient was r = .47 for stroke volume and r = .36 for cardiac output. LVID absolute error in cardiac output ranged -2.11 to +3.21 L/min. Use of other published formulas for calculating stroke volume from LVID did not improve accuracy. These data indicate that stroke volume and cardiac output cannot be accurately measured or reliably estimated from M mode left ventricular internal dimensions.

Purification of the synaptic membrane glycoprotein D2 from rat brain

D2 is a nervous-specific membrane protein enriched in fractions of synaptosomal membranes from rat brain. Recently, an immunochemical relationship between D2 and the chick cell adhesion molecule (CAM) has been demonstrated. There is reason to believe that D2 is involved in adhesion phenomena between neurites. The purpose of the present study was to purify and further characterize the D2 protein from rat brain. In the developed purification procedure synaptosomal membranes from rat brains were prepared and solubilized by means of non-ionic detergent. The subsequent purification steps were hydroxylapatite chromatography, wheat germ lectin affinity chromatography, gel filtration, and lysine affinity chromatography. The purified D2 was found to be enriched 240 times compared with the starting brain homogenate and 120 times compared with the synaptosomal membrane fraction. The recovery of D2 was 26% when the amount of D2 in the synaptosomal membrane fraction was set to 100%. The purified D2 antigen was used for production of monospecific rabbit antisera, and it was found to be composed of two polypeptides of apparent molecular weights 130,000 and 150,000, respectively.

Effect of acetylsalicylic acid on renal function in systemic lupus erythematosus

Glomerular filtration rate (GFR; 51Cr-EDTA clearance), serum creatinine concentration and urinary excretion of prostaglandins were measured in 8 patients with systemic lupus erythematosus (SLE) before and after 2 weeks of treatment with acetylsalicylic acid (ASA). ASA 65 mg/kg or up to 4 g/daily was given as a sustained release preparation. The serum salicylate concentration ranged from 0.3 to 1.6 mmol/l. Serum creatinine after 1 and 2 weeks and GFR after 2 weeks of ASA treatment showed no significant changes. There was a clearcut decrease in urinary excretion of prostaglandins PGE2 and PGF2 alpha, by 44% and 50%, respectively. It is concluded that therapeutic doses of ASA do not cause deterioration of GFR in patients with SLE and normal or moderately reduced renal function.

The influence of chronic high alcohol intake on blood pressure, plasma noradrenaline concentration and plasma renin concentration

1. Sixteen 44-year-old males with chronic high alcohol intake were investigated. Seventeen 44-year-old males with low alcohol intake from the same population served as controls. 2. Plasma noradrenaline concentrations did not differ significantly between individuals with high and low alcohol intake, neither at rest nor after acute stimulation induced by ambulation for 15 min. However, 63% (10 out of 16) of the individuals with high intake showed resting values within the upper quartile range for individuals with low intake. 3. Plasma renin concentration was twice as high (P less than 0.01) in the group with high alcohol intake as in the group with low intake. 4. Systolic as well as diastolic blood pressure was significantly higher (P less than 0.01) in the group with high intake compared with the group with low intake. 5. Sympathetic nerve activity, as defined from measurements of plasma noradrenaline concentration, is not uniformly increased in individuals with chronic high alcohol intake. The mechanism behind the increased plasma renin level as well as the possible role of the renin--angiotensin system in alcohol-induced hypertension remain unsettled.

A comparative study of atenolol and metoprolol in the treatment of hypertension

1 In an open, randomized cross-over investigation of thirteen patients (nine and four women, aged 37-67 years) with mild or moderate essential hypertension a comparison between atenolol and metoprolol was carried out in order to study the effects of 50, 100 and 200 mg given once daily on blood pressure and heart rate at rest and during exercise. 2 Before one beta-adrenoceptor blocking drug was replaced by the other in a patient an intervening drug-free interval of sufficient length was secured to allow an increase in the blood pressure to pretreatment levels. 3 A maximal fall in blood pressure was achieve with 50 mg atenolol once daily, with no further reduction when the dose was increased to 100 mg or 200 mg. Maximal blood pressure reduction was achieved with 100 mg metoprolol daily, while the hypertensive effect of 50 mg once daily was not consistent. Significant reductions in heart rate in all test situations were observed with 50 mg atenolol, while 200 mg metoprolol 100 was necessary to reduce exercise-induced tachycardia. 4 Atenolol 50 mg and metoprolol 100 mg once daily are efficient in treating mild or moderate hypertension and doses beyond these may not reduce the blood pressure further. On the contrary lower doses than generally recommended may be effective in the individual patient.

Serum lithium concentrations around the clock with different treatment regimens and the diurnal variation of the renal lithium clearance

The serum lithium concentration was determined around the clock in patients treated with conventional tablets given once daily, in the evening, and in patients treated with slow-release tablets given twice daily, in the morning and in the evening. Curve shapes differed markedly in the two groups, with much wider variation of serum concentrations in the former than in the latter. The data were used to calculate for the two patient groups the ratio of the mean serum lithium concentration over the 24-h day to the serum lithium concentration in blood samples drawn 12 h after the last intake of lithium. Around-the-clock determinations of the patients' renal lithium clearance showed about 20% lower values during the night than during the day.

Blood pressure, body fluid volumes and glomerular filtration rate during treatment with labetalol in essential hypertension

1 In a single blind study seventeen patients with mild or moderate essential hypertension and normal renal function were treated with labetalol alone in increasing doses from 300 via 600 to 1200 mg daily. 2 Average supine BP (systolic/diastolic) was reduced by 24/19 mm Hg. Seven patients attained a diastolic BP less than or equal to Hg. A significant postural fall in systolic BP was recorded, but no symptomatic orthostatic hypotension occurred. 3 In twelve patients measurements of plasma volume (125I-albumin), extracellular volume (82Br-space) and glomerular filtration rate (51Cr-EDTA clearance) on placebo and subsequently labetalol showed no systemic changes. 4 Side effects were few causing two withdrawals because of impotence and arthralgia. 5 It is concluded that monotherapy with labetalol results in clinically relevant, persistent and dose dependent reduction in BP in patients with mild or moderate essential hypertension, apparently without concomitant expansion of body fluid volumes or influence on glomerular filtration rate.

Isolation of intermediate filaments from rat astrocytes in culture

Intermediate filaments from rat astrocytes in culture were isolated by subcellular fractionation. The fractionation was monitored by electron microscopy and by quantitative immunoelectrophoresis using rabbit antibody directed against human glial fibrillary acidic protein (GFA). Morphologically intermediate filaments appeared helical with a mean diameter of 10 nm. Isolated filaments were disassembled at highly alkaline pH. After lowering of pH to slightly acidic values reassembled filaments, approximately 17 nm in diameter, were observed. As revealed by sodium dodecyl sulfate polyacrylamide gel electrophoresis the filament preparation was composed predominantly of a 51,000 molecular weight protein, corresponding to GFA. At high loads additional proteins of molecular weights 43,000 and 58,000 were detected. These latter proteins may represent residual actin and vimentin, respectively.

Prevalence of regional left ventricular dysfunction in patients with coronary artery disease

Left ventricular (LV) wall motion was evaluated prospectively by M-mode echocardiography for 503 patients, and results were compared with cinearteriographic and ECG findings. M-mode results from 92 of the patients were also compared with two-dimensional echocardiographic (2D) and LV angiographic findings. Abnormal echo motion was found by M-mode in 89 percent of patients with ECG Q waves of infarction and in 61 percent of coronary artery disease (CAD) patients without Q waves. Thirty-four percent of CAD patients had normal wall motion on M-mode examination. More abnormalities were detected when patients were examined using both M-mode and 2D, because M-mode was more sensitive in detecting anterior lesions and 2D was more sensitive in detecting posterior lesions. Both M-mode and 2D showed a low incidence of false-positive diagnosis (less than 2 percent) for patients with normal findings at cardiac catheterization.

Captopril combined with thiazide lowers renin substrate concentration: implications for methodology in renin assays

1. We have measured plasma concentrations of renin, renin substrate and angiotensins I and II as well as plasma renin activity in nine patients with severe or malignant hypertension during treatment with captopril, hydrochlorothiazide and propranolol. 2. On captopril and hydrochlorothiazide the plasma concentrations of renin substrate and angiotensin II decreased markedly, while renin and angiotensin I levels were increased. 3. The changes in renin substrate concentration suggest a consumption of substrate induced by an increased renin release. Further, the positive feedback of angiotensin II on hepatic renin substrate synthesis may be inhibited. 4. The sequential changes in renin release during captopril treatment should be monitored by measuring plasma renin concentration since plasma renin activity measurements will be profoundly influenced by the marked changes in plasma renin substrate concentration.

Antibody responses of remission leukemia patients receiving active specific and nonspecific immunotherapy

A solid-phase radioimmunoassay was utilized to evaluate the antibody response of 21 acute myelogenous leukemia (AML) patients to active specific immunotherapy with either pooled allogeneic AML blast cells or leukemia-associated antigen (LAA), admixed with BCG cell-wall skeleton (CWS). Five of 13 patients treated with LAA had a significant antibody response to LAA after immunotherapy. Antibody response correlated with an increased remission duration (159+ vs. 75+ weeks) and an increased survival (164+ vs. 98+ weeks). Two of eight patients treated with cells responded to LAA, and three patients had initially high anti-LAA antibody levels. In the total study, eight of 11 patients surviving longer than 2 1/2 years and six of seven patients maintaining a complete remission longer than 2 years were antibody responders. Neither protocol induced significant antibody to a normal spleen extract, BCG-CWS, or a measles recall antigen. However, five of seven patients with initially high levels of antibody to BCG (following weekly BCG scarification) were long-term survivors. These data suggest that the humoral immune response to immunotherapeutic agents may be a useful parameter for monitoring immunotherapy of AML patients.

Multivariate prognostic index in acute myocardial infarction for individual duration of hospitalization

To estimate the feasibility of an early and individualized discharge of acute myocardial infarction patients, a new prognostic index was constructed from Cox's regression model for survival analysis. From the first 5 d in the coronary care unit the significant prognostic variables in the index were heart failure (definite objective signs of congestive heart failure and/or definite cardiomegaly and/or pulmonary vascular enlargement on chest x ray in upright position), cardiogenic shock, atrioventricular block, and age. From the index the individual patient's probability of survival up to day 36 after admission could be directly predicted. The more positive the index, the higher was the probability of death. The prognostic efficacy was good, with two unexpected deaths from 149 patients in the lowest risk group. With a selected mortality risk of 5% from the day of discharge until day 30 after admission, 134 patients (52%) could be discharged on day 6. To have the risk of less than or equal to 5% after discharge another 54 patients (21%) would have to stay in the hospital for 24 d. Following this system of early and individualized discharge there were few serious post-discharge complications (one cardiac arrest and one ventricular tachycardia). Reinfarctions could not be predicted. This model could save around 2000 hospitalization days per year in this hospital.

Quantitation of glial fibrillary acidic protein in human brain tumours

The glial fibrillary acidic protein (GFA) content of 58 human brain tumours was determined by quantitative immunoelectrophoresis, using monospecific antibody against GFA. Astrocytomas, glioblastomas, oligodendrogliomas, spongioblastomas, ependymomas and medulloblastomas contained relatively high amounts of GFA, up to 85 times the concentration in parietal grey substance of normal human brain. GFA was not found in neurinomas, meningiomas, adenomas of the hypophysis, or in a single case of metastasis of adenocarcinoma. Non-glial tumours of craniopharyngioma and haemangioblastoma were infiltrated by reactive astroglia and showed considerable amounts of GFA.

Short-term prognostic index in acute myocardial infarction. Multivariate analysis by Cox model

A new multivariate stepwise linear regression analysis (Cox's model) with survival time as prognostic endpoint was utilized in 281 patients with acute myocardial infarction. From 18 prognostic factors occurring during the first 5 days in the Coronary Care Unit a new prognostic index was calculated for the chance of survival in the first 36 days after admission. The significant prognostic variables were heart failure, cardiogenic shock, atrioventricular block and age. The total group of patients was classified in 6 subgroups with different mean indices and prognosis. There were 2 large groups of patients with relative bad and good prognosis (with and without heart failure). Over half of the patients had no prognostic variables. There was a trend of overestimating the expected deaths. A definite cardiac cause of death was shown by 23 patients (82%). This prognostic index based on the 4 variables can for the individual patient predict the chance of survival, which can be the basis of an individualized duration of hospital stay.