[Human adult left atrial volume estimated by M-mode echocardiography]

There are few systematic reports of the regression equation for humans, for estimating left atrial volumes from the anteroposterior left atrial dimensions measured by M-mode echocardiography (LADAP). In addition, several pitfalls were inherent in the M-mode method. In view of these pitfalls, we estimated the anteroposterior left atrial dimensions by directing the ultrasonic beam toward the "center" of the left atrium under the guidance of two-dimensional echocardiography. Simultaneously, we estimated left atrial volumes from anteroposterior and left lateral biplane left atrial angiocardiograms using a film changer at three frames per sec. The maximum elapsed time between the echocardiographic and angiocardiographic studies was two days. Left atrial volumes were calculated using the method of Sauter et al. Maximum left atrial volume was calculated at the end of the T wave. The results were as follows: For phantom experiments, a cylindrical container with varying amounts of contrast material was tested by biplane angiography using a film changer. The actual volume (x) and the calculated volume (y) were in good agreement with the regression equation; y = 1.05x-0.1 (r = 0.99, p less than 0.001, n = 6). The anteroposterior left atrial dimension in M-mode echocardiography (LADAP: x axis) and left atrial volume (ml) angiocardiographically obtained (y axis) showed the curvilinear regression equation; y = 1.4x3+23 (r = 0.83, p less than 0.01, n = 19). The relation between the left atrial cross-sectional area (cm2) obtained from the left ventricular long-axis view by two-dimensional echocardiography (x axis) and the left atrial volume (ml) by angiocardiography using a film changer (y axis) showed the regression equation; y = 1.2x1.5+17 (r = 0.82, p less than 0.01, n = 14). As a preliminary study, we calculated left atrial volume (LAVcine) for five patients by performing biplane cineangiocardiography at 50 frames per sec. The results were nearly the same as those obtained using a film changer. In summary, the derived equation predicts left atrial volume using M-mode echocardiography with considerable accuracy.

Inner volume MR imaging: technical concepts and their application

Although cross-sectional magnetic resonance examination of the head and body is useful for screening large regions of tissue, subsectional regions of the head and body often need to be examined. Orthogonally directed, selectively irradiated planes with different flip angles produce a spatially limited signal region from which two- or three-dimensional volume images can be reconstructed. Images with limited fields-of-view can be acquired in reduced imaging time. We present a general description of this technique. These subsectional or "inner volume" images eliminate respiratory motion artifacts by excluding moving tissues from the imaged volume. A result of this technique is a high signal from rapid pulsatile blood flow, produced without cardiac gating the pulse sequence.

Magnetic resonance imaging performance: a comparison of sodium and hydrogen

Although many nuclei can be used to produce magnetic resonance (MR) images, technical considerations dictate the choice of certain of these. Hydrogen is the most favorable, followed by sodium. We present an evaluation of the imaging performance of sodium MR imaging based on imager performance and biologic factors. Because it is hampered by high operating fields, low signal-to-noise levels, and radiofrequency power deposition constraints, careful clinical comparisons will be needed to identify a diagnostic niche that could take advantage of the large sodium differences known to exist within biologic systems.

Portal vein or hepatic vein? A curious aberrant vasculature in the liver with idiopathic portal hypertension

The existence of aberrant vasculatures has been described as one of the characteristic findings in the liver with idiopathic portal hypertension (IPH). In this paper, the morphological features and the genesis of aberrant vasculatures were studied on the basis of autopsy and biopsy materials of IPH and animal experiments. Aberrant vasculatures in IPH livers are characterized as thin-walled vessels located mainly adjacent to the portal tracts and at times in the hepatic lobules. Although some of them are morphologically very similar to hepatic vein branches, they are portal in nature. These aberrant vessels develop in order to compensate for portal circulatory insufficiency due to obliteration of portal vein branches, and play an important role in maintaining an adequate blood supply to the parenchyma. It is predicted that decrease of these intrahepatic collateral vessels is responsible for or related to parenchymal atrophy and deterioration of liver function in the advanced stage of this disease. We regard these vasculatures as characteristic of the intrahepatic portal venous obstruction, particularly with portal hypertension accompanied by increased portal blood flow.

A new form of amyloid protein associated with chronic hemodialysis was identified as beta 2-microglobulin

Amyloid fibrils were isolated from amyloid-laden tissue obtained from a chronic hemodialysis patient with carpal tunnel syndrome. After solubilization in guanidine HCl, a significant amount of the protein was located in a homogeneous low molecular weight fraction. The protein was found to be identical to beta 2-microglobulin, with regard to its molecular weight of 11,000, amino acid composition and 16 amino-terminal amino acids: Ile-Gln-Arg-Thr-Pro-Lys-Ile-Gln-Val-Tyr-Ser-Arg-His-Pro-Ala-Glu-. These results demonstrate that the amyloid associated with chronic hemodialysis contains as major component a new form of amyloid fibril protein that is homologous to beta 2-microglobulin.

Esophageal varices: correlation of left gastric venography and endoscopy in patients with portal hypertension

Selective left gastric venography was performed via percutaneous transheptic catheterization in 100 patients with portal hypertension to study hemodynamics and left gastric collaterals. Flow was hepatofugal in 81 patients, while 63 had varices supplied by the left gastric vein; azygos/hemiazygos collaterals were seen in 27 patients, gastrorenal shunts in 18, and other collaterals in 58. In 79 cases, enlarged, tortuous veins arising from thin parallel vessels at the esophagogastric junction on venography corresponded with varices on endoscopy in both size and course. Venography failed to show small varices which were seen endoscopically, whereas endoscopy often interpreted non-tortuous veins as varices. Using endoscopy as a reference, the sensitivity of venography for varices was 76%, specificity 100%, and accuracy 78%. There was a significant correlation between venographic demonstration of varices and previous hematemesis. Left gastric venography is necessary prior to embolization of varices and is also useful in their diagnosis as well as study of hemodynamics and assessment of bleeding risk.

Pulmonary blood volume and pulmonary extravascular water volume in men

In order to estimate the pulmonary blood volume between the pulmonary artery trunk and the left atrium (PBV PAT-LA), simultaneously with the pulmonary extravascular water volume (PEWV) in the chronically stable cardiac patients, we employed the double indicator dilution method using heat as a diffusible indicator and indocyanine green as a non-diffusible indicator. The PEWV was obtained as the extravascular lung thermal volume estimated in the aortic root (LTVAo). In the group of hemodynamically normal patients, in spite of ischemic heart disease (G-N, n = 22), the mean pulmonary artery wedge (PAW) pressure was 9.3 +/- 3.9 mmHg (mean +/- SD), PBVPAT-LA was 8.95 +/- 1.71 ml/kg, LTVAo was 5.71 +/- 1.37 ml/kg and PBVPAT-LA/LTVAo ratio was 1.64 +/- 0.44. In the group of hemodynamically slightly compromised patients with mitral stenosis (G-MS, n = 13), the mean PAW pressure was 14.2 +/- 2.6 mmHg, PBVPAT-LA was 11.12 +/- 2.86 ml/kg, LTVAo was 5.68 +/- 1.41 ml/kg and PBVPAT-LA/LTVAo ratio was 2.02 +/- 0.58. Between the two groups, LTVAo was not statistically significant, whereas the mean PAW pressure, PBVPAT-LA and PBVPAT-LA/LTVAo ratio were all significantly increased in G-MS (p less than 0.05). Neither PBVPAT-LA nor LTVAo correlated with the mean PAW pressure in both groups. From PBVPAT-LA/LTVAo ratio, fluid volume in the intravascular space was greater than that in the extravascular space in both groups. From LTVAo, PEWV in G-MS was identical with that in G-N, in spite of the elevated mean PAW pressure. Therefore, even in the patients with mitral stenosis, the interstitium in the lung is kept "dry" under conditions of the mean PAW pressure below 20 mmHg. The safety factors that prevent pulmonary edema, as evidenced in animal studies, seem to operate effectively in man.

Multiple spin-echo magnetic resonance imaging

Spin-echo magnetic resonance (MR) imaging detects a variety of pathologic states with great sensitivity. A technique for producing multiple spin-echo images in multisection operation is presented. This method of intensity-image acquisition is compared with retrospective intensity-image synthesis from routine data sets. Both yield long echo time (TE) images with similar image contrast and comparable and often increased diagnostic utility. Technical and clinical considerations are addressed, including signal-to-noise levels, flow effects, and patient throughput.

Pathogenesis of portal sclerosis in the liver with idiopathic portal hypertension. Observations of 19 autopsy cases and animal experiments

The pathomorphological changes of intrahepatic portal veins were studied in 19 autopsy cases of idiopathic portal hypertension (IPH), and the pathogenesis of portal sclerosis was discussed by the observations on the human and experimental materials. The degree and morphological appearance of intimal lesions vary from vessel to vessel. Fibro-cellular proliferation of subendothelial tissue and incorporation of organized mural thrombi were suggested as the cause of intimal thickening in the portal veins. Animal experiment showed that injury of portal vein wall was followed by intimal hyperplasia and/or incorporation of mural thrombi, and resulted in portal sclerosis similar to that of IPH liver. The cause of portal phlebosclerosis in IPH can not be explained by passive congestion alone. There might be a certain possibility of direct injurious effect in the vessel wall in the pathogenesis of portal lesions of IPH. The following pathogenesis of portal sclerosis in IPH is postulated: phlebo-sclerotic changes of the portal veins are initiated by injury to the vessel wall due to unknown cause(s) and accelerated by secondary thrombosis and/or mechanical injury due to increased portal pressure.

A problem intrinsic to the measurements of the pulmonary extravascular water volume by the thermal-dye technic with the sampling site in the bifurcation of the aorta. Thermal equilibrium with the aortic wall

When estimating the pulmonary extravascular water volume (PEWV) as the lung thermal volume (LTV), by the double indicator dilution technic using heat and indocyanine green (ICG), a part of the left ventricular wall comes to the thermal equilibrium, and this leads to an overestimation of PEWV, when the samplings are made in the aortic root. In a previous study from this laboratory, this overestimation was approximately 10% of the measured LTV in the aortic root. In the present study, we evaluated the extent to which the thermal equilibrium with the aortic wall would cause LTV to slightly overestimate PEWV. For this purpose, we injected a mixture of the indicators into the right atrium, and recorded the indicator dilution curves at the bifurcation of the aorta (AB). We then compared this LTV with the one calculated from the indicator dilution curves recorded simultaneously in the aortic root (Ao). We obtained the following results: Firstly, the values of cardiac output (CO) from the dye dilution curve and from the thermodilution curve at two sites, Ao and AB, were all in agreement. Secondly, LTV estimated in Ao (LTVAo) and LTV estimated in AB (LTVAB) were not the same, and their relationships were: LTVAB = 1.21 X LTVAo + 0.44 (ml/kg), n = 32, (r = 0.98, p less than 0.001) A close agreement of CO determined at two sites indicated that there was virtually no loss of heat between the two sampling sites, Ao and AB. An excess of LTVAB over LTVAo came to about 20%, and this excess appeared to be ascribable to the incorporation of the thermally equilibrated "volume" of the aortic wall. This finding appeared to be a challenge to the validity of estimating LTV when sampling the indicators in the distal abdominal aorta.

Thin-section definition in magnetic resonance imaging. Technical concepts and their implementation

In multisection magnetic resonance imaging, gradient strength and earliest desired echo time (TE) set a limit to the thinnest section achievable. Offset radio-frequency irradiation techniques and phase encoding within a thick section make possible the production of thin sections of clinically useful quality in practical imaging times.

A comparison of saddle-shaped and solenoidal coils for magnetic resonance imaging

Differences in magnetic resonance (MR) imaging signal-to-noise (S/N) performance between saddle-shaped and solenoidal coils have been postulated. Each coil shape is tied to a particular magnetic field configuration, so that they are not typically interchangeable except in special situations. The solenoidal coil is predicted to have a two- to three-fold advantage over the saddle-shaped coil. Simple basic arguments raise a dispute with this assertion. Experiments show that both coils produce essentially equivalent S/N levels.

Physiologic approach to dialysis-induced hypoxemia. Effects of dialyzer material and dialysate composition

This study was undertaken to evaluate the effects of membrane-related complement activation and dialysate composition on dialysis-associated hypoxemia. Seven chronic hemodialysis patients were hemodialyzed 3 times sequentially with the following three combinations; Cuprophan membrane with acetate dialysate, polymethylmethacrylate (PMMA) membrane with acetate dialysate, and PMMA membrane with bicarbonate dialysate. During dialysis with acetate dialysate, the pulmonary diffusing capacity (DLco) at 30 min after the start of dialysis was decreased to 88% (p less than 0.01) of the predialysis value with PMMA and to 79% (p less than 0.01) with Cuprophan, and the degree of DLco on PMMA membrane was different from that on Cuprophan (p less than 0.01). The degree of leukopenia with PMMA was less than that with Cuprophan. However, the fall in DLco did not alter the alveolar-arterial O2 tension gradient. Although the changes in transcutaneous PO2 (tcPO2) were not constant in all three combinations, a distinct fall in tcPO2 was observed in the first half of dialysis with acetate dialysate. During dialysis with acetate dialysate but not with bicarbonate, the extracorporeal dialyzer removed an average of 60 ml/min of CO2, and the respiratory quotient dropped from a mean predialysis value of 0.86 to 0.59 (p less than 0.001). The arterial CO2 tension was not significantly changed throughout dialysis, but the alveolar ventilation decreased significantly in proportion to the fall in carbon dioxide output. The arterial tension fell from a control level of 91 +/- 6 to 77 +/- 8 mm Hg (p less than 0.01) in 30 min. It is concluded that, in spite of a fall in DLco, dialysis-induced hypoxemia in this group of patients on maintenance dialysis is caused by CO2 loss via the dialyzer, resulting in reflex hypoventilation.

Liposome-type artificial red blood cells stabilized with carboxymethyl chitin

Liposome-type artificial red blood cells (ARBC) stabilized with carboxymethyl chitin (CM chitin) containing human hemolysate were prepared by a two-step emulsification technique, Oxygen binding abilities of the ARBC and human hemolysate were measured by the use of a Clark-type oxygen electrode. Both of theARBC and human hemolysate exhibited a striking similarity in oxygenation behavior, indicating that the oxygen binding ability of the former is almost identical with that of the latter. Disintegration tests on the ARBC using the enzymes (lysozyme, chitinase and phospholipase C), that can digest the components of the ARBC membrane, suggested that the membrane has a structure in which the phospholipid layer is covered by a mesh of CM chitin molecules. The acute toxicity of the ARBC to male mice (BALB/c) was examined and the LD 50 value of the ARBC for 2 ml of intravenous injection was evaluated to be 13.8 ml/kg by means of the Litchfield-Wilcoxon method.

Solubilization of immune complex deposits by native 7S IgG molecules in lupus glomerulonephritis--a possible antigen excess effect on rheumatoid factor-IgG complexes

IgM and IgG class rheumatoid factor (RF) containing glomerular immune complex (IC) deposits were detected in renal biopsy material from 10 out of 123 patients with various forms of glomerulonephritis (GN) by an immunofluorescent assay using FITC conjugated aggregated human IgG(FAHIgG). In lupus GN, six out of 28 cases (23.5%), showed such activity. Solubilization of glomerular IC deposits in frozen sections of lupus GN was observed after a 5 h incubation with native 7S IgG. The binding of FAHIgG to glomerular IC deposits and solubilization of deposits by excess HIgG were also confirmed in sections of two types of rat experimental GN in which HIgG acted as exogenous antigen; in situ IC formation type GN in cationized HIgG planted kidneys and chronic serum sickness type GN. These results suggest a possible antigen excess mechanism contributing to the solubilization of glomerular IC deposits via RF and IgG interactions in lupus GN.

Magnetic resonance imaging strategies for heart studies

Given a suitable trigger signal, cardiac synchronized magnetic resonance (MR) imaging is simple to implement; however, single section techniques are not efficacious, especially when the heart rate sets the repetition interval. We demonstrate multi-section, double, and single-echo imaging, any of which rapidly covers the cardiac volume; 3-D modes capable of achieving very thin sections; and cycled multi-section imaging capable of efficaciously providing dynamic data on heart motion. These modes form a complementary, powerful set of options for clinical work.

Pulsatile blood velocity in human arteries displayed by magnetic resonance imaging

The authors describe a new method for magnetic resonance (MR) imaging of flowing protons which can illustrate relative blood velocity in the arteries supplying the brain. The magnetic gradient pulse sequence was synchronized to the cardiac cycle at 100-msec. increments to track pulsatile blood flow perpendicular to the image plane. The magnitude of the signal increased with the velocity of blood in major arteries flowing in the direction of the spatially offset refocusing plane. The blood velocity in the vertebral and internal carotid arteries varied as a function of the phase of the cardiac cycle, and the velocity profiles across the vascular lumina were compatible with laminar flow.

Permeability of ethylcellulose microcapsules towards phenobarbital

Inward permeation from the surrounding medium of phenobarbital through the wall of water-loaded ethylcellulose microcapsules was investigated as a function of capsule size under the conditions of constant total capsule volume and constant total capsule surface area. The experimental data obtained were analysed in terms of capsule wall density and drug partition coefficient. The drug permeability coefficients calculated according to an equation derived from Fick's first law of diffusion were found to increase with decreasing capsule size in both constant total capsule volume and constant total capsule surface area experiments. The wall density and the drug partition coefficient also exhibited the same trend. Based on these findings, it was concluded that the drug permeation through ethylcellulose microcapsule membrane occurs predominantly by a solution-diffusion mechanism.

[Antitumor effect of FU-O-G, new antitumor agent, following long term administration]

FU-O-G, the O-glucuronide methylester of 5-fluorouracil (5-FU), is a compound with a unique chemical structure. It is an antitumor agent of the prodrug type which exerts its activity by enzymatically liberating 5-FU in tumor tissues. It has been reported that the antitumor activity of this compound is superior to those of 5-FU and Tegafur (FT-207) in the treatment of various transplantable tumors. In this study, long-term administration of FU-O-G to mice bearing relatively slow-growing tumors such as Lewis lung carcinoma, mammary tumor FM3 A and hepatoma MH-134 was carried out. Consequently, FU-O-G was shown to be remarkably effective against those tumors, whereas 5-FU and FT-207 were hardly effective. Long-term daily administration was shown to be more effective than intermittent dosage in the treatment of Lewis lung carcinoma. In combination therapies of FU-O-G with other antitumor drugs, FU-O-G exhibited a synergistic effect against Lewis lung carcinoma when combined with Carboquone (CQ) or Nimustine hydrochloride (ACNU).