The influence of viscosity-enhancing agents on oral absorption of drugs

The objective of this study was to evaluate the influence of viscosity-enhancing agents on oral absorption of metoprolol (MPL) and bisoprolol (BPL). Although the viscosity values were similar for MPL and BPL in hydroxypropyl methylcellulose (HPMC, 1.2 % (w/w)) and polyvinyl alcohol (PVA, 8.8 % (w/w)) solutions, the order of diffusion rate constants of the drugs in media were phosphate buffer solution (reference) > HPMC solution > PVA solution. In in vivo rat intestinal absorption experiments showed that the C_max and AUC values of the drugs were lowest when they were administered into the rat jejunum in a PVA solution. In vitro binding studies showed that this may have been due to adsorption of the drugs to PVA molecules, resulting in decreased free fractions of the drugs. Our results indicated that intestinal absorption of the drugs in PVA solution was influenced both by decreased diffusion of the drugs and by interaction with PVA. Since various viscosity-enhancing agents are widely used as pharmaceutical and food additives, these findings may be of significance for understanding therapeutic efficacy and safety of oral drug products.

Predictors of inhalation burn injury using fire site information

Inhalation burn injury (IBI) is a risk factor for mortality in burn patients. However, it is difficult to diagnose IBI using traditional physical examination alone, especially in prehospital settings. Therefore, facial burn patients are usually treated for suspected IBI. In the present study, we investigated whether fire site information could predict IBI as an alternative to traditional physical examination. This retrospective single-centre analysis involved 27 facial burn patients with suspected IBI who were admitted between 2014 and 2016. The patients were divided into two groups (IBI and non-IBI) according to bronchoscopy findings. Fire site information was compared between the two groups. The IBI (n = 13) and non-IBI (n = 14) groups were compared. Domestic fire was more frequent in the IBI group (69% vs. 29%, P = 0.035). The IBI group included one patient with carboxyhemoglobin ≥10% on admission. Prehospitalization fire site information, particularly domestic fires, might predict IBI in facial burn patients..

Disposition of TF-PEG-Liposome-BSH in tumor-bearing mice

BNCT requires high concentration and selective delivery of (10)B to the tumor cell. To improve the drug delivery in BNCT, we conducted a study by devising TPLB. We administrated three types of boron delivery systems: BSH, PLB and TPLB, to Oral SCC bearing mice. Results confirmed that (10)B concentration is higher in the TPLB group than in the BSH group and that TPLB is significantly effective as boron delivery system.

[Diagnostic image (115). A comatose woman after a car collision. Subdural 'contre-coup'-hematoma without cranial fracture, with brain edema, and crowding]

A 70-year-old woman was hit by a truck from her right side when riding her bicycle. CT revealed contre-coup severe brain injury.

Optical coherent reflectometry: a new technique to guide invasive procedures

The success rate of percutaneous transluminal coronary angioplasty for chronic total arterial occlusions is still unsatisfactory. Inability to cross the lesion with a guidewire is a major cause of failure. Optical coherent reflectometry (OCR) is a new method of using laser light to measure the depth of tissue from the end of an optic fiber. This study tests whether an OCR prototype guidewire provides a guidance system that might be useful to assist reopening chronic total arterial occlusions. An OCR fiber optic within a 0.014" hypotube was developed using the interference pattern of two reflected light beams (wave length 1,300 nm). To determine if OCR can distinguish different tissue types, plaques of human lower extremity arterial segments were visually divided into three types (calcified, white, or yellow). The slope of the initial reflectance of the OCR curve was calculated and compared between the three groups. In six other arteries, the OCR wire was advanced longitudinally through occluded human artery segments in vitro. Guidewire position was determined by OCR and compared to the position of the guidewire tip observed simultaneously by intravascular ultrasound (IVUS) imaging. In 16 arterial surface segments, calcified plaques had a significantly steeper slope than white or yellow plaques (-227.2 +/- 82.2; -81.5 +/- 12.9; -103.6 +/- 19.6 dB/mm; P < 0.01). For the determination of the guidewire position, IVUS and OCR corresponded correctly in 82% of 28 measurements. Sensitivity and specificity of OCR for detection of plaque versus the media/adventitia boundary were 79% and 89%, respectively (P < 0.001). OCR can distinguish calcified from noncalcified plaque and may distinguish plaque from the media/adventitia boundary. This technology may be useful as a means to help navigate a guidewire safely through an occluded artery.

Angioplasty and stent placement in chronic occlusion of the superficial femoral artery: technique and results

PURPOSE

To improve the patency rate for angioplasty in chronic occlusion of the superficial femoral artery by deploying stents after angioplasty.

MATERIALS AND METHODS

Angioplasty and stent placement were performed in 61 arteries in 48 male patients. The mean occlusion length was 13.5 cm and the mean stent length was 30 cm. Patency rates were analyzed at 6 months and at 1, 2, 3, and 4 years. The predictors of restenosis were analyzed by univariate and multiple logistic regression.

RESULTS

Patency rates were 87% at 6 months, consisting of 74% primary, 6% primary assisted, and 7% secondary; 79% at 1 year, consisting of 47% primary, 19% primary assisted, and 13% secondary; 72% at 2 years, consisting of 36% primary, 26% primary assisted, and 10% secondary; 70% at 3 years, consisting of 26% primary, 22% primary assisted, and 22% secondary; and 63% at 4 years, consisting of 25% primary, 0% primary assisted, and 38% secondary. There was a 15% morbidity rate and one mortality as a result of retroperitoneal bleeding. Better patency rates were noted at all time intervals in diabetic limbs, 7-mm-diameter versus 10-mm-diameter stents, shorter obstructions and shorter stents, nonsmokers, in limbs in which urokinase was not necessary after stent deployment, and in limbs with an International Society of Cardiovascular Surgery (ISCVS) classification under 3. Patency rates were not affected by age, race, number of trifurcation vessels patent, experience in performing the procedures, and procedures requiring less time. By multivariate logistic analysis, the independent predictors of patency at 6 months were postprocedure ankle/brachial index (ABI) and shorter stent length; at 1 year, preprocedure ABI, shorter stent length, and the presence of diabetes; at 2 years, preprocedure ABI and the presence of diabetes; and at 3 years, the preprocedure ABI.

CONCLUSIONS

The techniques used to reestablish antegrade flow in these superficial femoral arteries yielded a high success rate. In addition, the use of angioplasty with stents may improve patency rates over angioplasty without stents.

Tumor regression by inductive hyperthermia combined with hepatic embolization using dextran magnetite-incorporated microspheres in rats

We formulated a novel preparation of microspheres incorporating dextran magnetite complex (DM-MS), which enable magnetic field-induced heating for the induction of hyperthermia. Using a 500 kHz magnetic field combined with arteriolar embolization of DM-MS, inductive hyperthermia was performed for the treatment of liver tumors in rats. Three days after treatment, the percentage increase of tumor volume in the embolo-hyperthermia, embolization alone, and control groups were 28%, 124%, and 385%, respectively, with the embolo-hyperthermia group differing significantly from the remaining groups. This study demonstrated the feasibility of combining embolization of DM-MS with hyperthermia as an antitumor therapy.

Psyllium shifts the fermentation site of high-amylose cornstarch toward the distal colon and increases fecal butyrate concentration in rats

We examined the combination effects of psyllium (PS) and resistant starch on large bowel short-chain fatty acids (SCFA). Rats were fed one of the following four diets: low amylose (LAS) or high amylose cornstarch diets (HAS, 50 g/kg diet) with or without 15 g PS/kg diet (LAS/PS and HAS/PS diets). HAS and/or PS were substituted for the same amounts of LAS in diets. Cecal butyrate concentrations were significantly higher in rats fed the HAS and HAS/PS diets than in those fed the LAS and LAS/PS diets. However, butyrate and total SCFA concentrations in rats fed the HAS diet decreased along the length of the colon and fecal butyrate concentration was reduced to one-third of that in the cecum. In contrast, the HAS/PS diet maintained higher butyrate concentrations throughout the large bowel. Fecal butyrate concentration in the HAS/PS diet-fed group significantly exceeded the sum of the concentrations in rats fed the LAS/PS and HAS diets. PS supplementation to the HAS diet significantly increased fecal starch excretion by 10 fold compared with that of rats fed the HAS diet. There was a positive correlation between fecal butyrate concentration and fecal starch excretion (r = 0.709, P < 0.0001). In a further experiment, ileorectostomized rats were fed the HAS and HAS/PS diets. From the difference in fecal starch excretion between normal and ileorectostomized rats, starch degradation by large bowel microflora in rats fed the HAS and HAS/PS diets was deduced to be 96% and 63%, respectively. These findings support the hypothesis that PS may delay the fermentation rate of HAS in the cecum and shift the fermentation site of HAS toward the distal colon, leading to the higher butyrate concentration in the distal colon and feces.

Oligo-L-methionine and resistant protein promote cecal butyrate production in rats fed resistant starch and fructooligosaccharide

We examined the role of resistant protein and peptides in promoting cecal butyrate production in rats fed rapidly fermentable carbohydrates. Rats were fed diets containing raw potato starch (RPS, 200 g/kg diet) or fructooligosaccharide (FOS, 60 g/kg diet) with casein, soy or rice protein (250 g/kg diet) for 13 d. In rats fed RPS with casein, the major cecal organic acid was acetate (441 micromol), but lactate and succinate were also found in considerable amounts (324 micromol). Succinate was the major cecal organic acid (235 micromol) in rats fed FOS with casein. When rice protein was fed with RPS, the contribution of lactate was significantly lower and that of propionate tended to be higher (P < 0.1) than in rats fed casein. In rats fed rice protein with FOS, cecal butyrate and acetate were greater and cecal succinate was lower than in rats fed casein with FOS (P < 0.05). Despite the similar amounts of undigested protein in rice and soy proteins, soy protein did not similarly affect cecal butyrate in rats fed FOS or RPS. In another experiment, rats were fed diets containing high amylose cornstarch (HAS, 200 g/kg diet) with casein, casein + oligo-L-methionine (OM, 3 g/kg diet), soy protein, soy protein + OM (3 g/kg diet) or rice protein (250 g/kg diet) for 10 d. OM (digestibility, 31%) was substituted for the same amount of casein. Rats fed rice protein had greater cecal butyrate than rats fed casein (P < 0.05). OM supplementation to casein or soy protein increased cecal butyrate compared with rats fed casein or soy protein alone (P < 0.05). These data support our hypothesis that resistant protein and peptides promote cecal butyrate production and suggest that the differing potency of rice and soy proteins in promoting cecal butyrate production might be explained in part by the different amino acid composition of resistant protein.

Differences in the effect of iron-deficient diet on tissue weight, hemoglobin concentration and serum triglycerides in Fischer-344, Sprague-Dawley and Wistar rats

This study was designed to examine the differences in the effect of an iron-deficient diet on iron metabolism in Fischer-344 (FC), Sprague-Dawley (SD) and Wistar (WT) rats based on hemoglobin (Hb), hematocrit (Hct), serum iron levels, growth rate and organ weight. Hb concentration was higher in FC rats (14 mg/100 mL) on the initial day than in SD (10) and WT (10) rats. Although the Hb level was significantly decreased in FC rats fed an iron-deficient (ID, 8 mg/kg) diet for 33 d compared to the FC rats fed an iron-adequate (IA, 50 mg/kg) diet, the relative concentration of Hb was high in FC rats fed the ID diet as compared to the SD and WT rats fed the same diet. A similar relationship was detected between Hct and serum iron concentrations. Although serum triglycerides (TG) were significantly increased in each rat strain fed the ID diet as compared to the IA diet, the percentage of the value for the IA diet was lowest in FC rats (119%) fed the ID diet as compared to the SD (328) and WT (394) rats fed the same diet. Retroperitoneal fat pad was decreased in FC, SD and WT rats fed the ID diet as compared to the IA diet. SD rats were particularly sensitive to the reduction of retroperitoneal fat pad. The results suggested that rat strains responded differently to dietary iron inadequacy, and that FC rats were less sensitive to an iron-deficient diet as compared to the SD and WT rats.

Calcified plaque cross-sectional area in human arteries: correlation between intravascular ultrasound and undecalcified histology

BACKGROUND

The purpose of this investigation was to quantify the amount of intralesional calcium detected by intravascular ultrasound (IVUS) compared with undecalcified histology in human arteries. This method preserves intralesional calcium and reduces sectioning artifacts, thereby providing an accurate measure of calcium plaque morphology.

METHODS AND RESULTS

Ten arterial segments (5 coronary, 5 iliac) were obtained at autopsy. IVUS imaging was performed with a 4.9F catheter at an automated pullback rate of 1.0 mm/s. The undecalcified arteries were dehydrated in ascending alcohol and polymerized in glycol methylmethacrylate. The arteries were cut into 200-microm sections with an Isomet low-speed saw and stained with Goldner's trichrome. The lumen cross-sectional area, the calcium plaque cross-sectional area, the calcium plaque depth, length, and angle of arc of calcified plaque were measured from the IVUS images and histologic sections. In 24 selected cross sections, there were 38 separate calcium plaques. An independent observer correctly identified 34 of 38 calcified plaques for a sensitivity of 89% and specificity of 97%. The total mean calcified plaque cross-sectional area measured from histology was 4.6 +/- 4.1 mm2 compared with 2.8 +/- 2.3 mm2 by IVUS (P =.002). Plaque depth measured by histology was 1.2 +/- 0.4 mm versus 0.7 +/- 0.2 mm by IVUS (P =.001). The length of calcium plaques measured by histology was 3.6 +/- 1.78 mm versus 3.6 +/- 1.5 mm for IVUS (r = 0.79).

CONCLUSIONS

IVUS accurately depicts circumferential calcified lesions with high sensitivity (89%) and specificity (97%). However, IVUS underestimates the total calcified plaque cross-sectional area by 39%. This is mainly because of the inability of the ultrasound to penetrate intralesional calcium, which leads to an underestimation of the depth of calcium by 45%.

Video networking of cardiac catheterization laboratories

BACKGROUND

The purpose of this study was to assess the feasibility and accuracy of a video telecommunication network to transmit coronary images to provide on-line interaction between personnel in a cardiac catheterization laboratory and a remote core laboratory.

METHODS

A telecommunication system was installed in the cardiac catheterization laboratory at Kaiser Hospital, Los Angeles, and the core laboratory at the University of California, Irvine, approximately 40 miles away. Cineangiograms, live fluoroscopy, intravascular ultrasound studies and images of the catheterization laboratory were transmitted in real time over a dedicated T1 line at 768 kilobytes/second at 15 frames/second. These cases were performed during a clinical study of angiographic guidance versus intravascular ultrasound (IVUS) guidance of stent deployment. During the cases the core laboratory performed quantitative analysis of the angiograms and ultrasound images. Selected images were then annotated and transmitted back to the catheterization laboratory to facilitate discussion during the procedure.

RESULTS

A successful communication hookup was obtained in 39 (98%) of 40 cases. Measurements of angiographic parameters were very close between the original cinefilm and the transmitted images. Quantitative analysis of the ultrasound images showed no significant difference in any of the diameter or cross-sectional area measurements between the original ultrasound tape and the transmitted images. The telecommunication link during the interventional procedures had a significant impact in 23 (58%) of 40 cases affecting the area to be treated, the size of the inflation balloon, recognition of stent underdeployment, or the existence of disease in other areas that was not noted on the original studies.

CONCLUSIONS

Current video telecommunication systems provide high-quality images on-line with accurate representation of cineangiograms and intravascular ultrasound images. This system had a significant impact on 58% of the cases in this small clinical trial. Telecommunication networks between hospitals and a central core laboratory may facilitate physician training and improve technical skills and judgement during interventional procedures. This project has implications for how multicenter clinical trials could be operated through telecommunication networks to ensure conformity with the protocol.

Angiographic and intravascular ultrasound predictors of in-stent restenosis

OBJECTIVES

This study was performed to determine predictors of in-stent restenosis from a high volume, single-center practice.

BACKGROUND

Intracoronary stents have been shown to reduce the restenosis rate as compared with balloon angioplasty, but in-stent restenosis continues to be an important clinical problem.

METHODS

Between April 1993 and March 1997, 1,706 patients with 2,343 lesions were treated with a variety of intracoronary stents. The majority of stents were placed with high pressure balloon inflations and intravascular ultrasound (IVUS) guidance. Angiographic follow-up was obtained in 1,173 patients with 1,633 lesions (70%). Clinical, angiographic and IVUS variables were prospectively recorded and analyzed by univariate and multivariate models for the ability to predict the occurrence of in-stent restenosis defined as a diameter stenosis > or =50%.

RESULTS

In-stent restenosis was angiographically documented in 282 patients with 409 lesions (25%). The restenosis group had a significantly longer total stent length, smaller reference lumen diameter, smaller final minimal lumen diameter (MLD) by angiography and smaller stent lumen cross-sectional area (CSA) by IVUS. In lesions where IVUS guidance was used, the restenosis rate was 24% as compared with 29% if IVUS was not used (p < 0.05). By multivariate logistic regression analysis, longer total stent length, smaller reference lumen diameter and smaller final MLD were strong predictors of in-stent restenosis. In lesions with IVUS guidance, IVUS stent lumen CSA was a better independent predictor than the angiographic measurements.

CONCLUSIONS

Achieving an optimal stent lumen CSA by using IVUS guidance during the procedure and minimizing the total stent length may reduce in-stent restenosis.

Effect of dietary magnesium level on nephrocalcinosis and growth in rats

We studied the extent of kidney calcification by varying dietary levels of Mg, based on pathological examinations and calcium (Ca) and magnesium (Mg) balance tests. AIN-76 diets containing varying levels of Mg--0.3 (-M), 1.3 (1/20M), 2.4 (1/10M), 9.2 (1/5M), 19 (control), 38 (2M), 102 (5M), and 187 (10M) mmol/kg diet--were fed to 3-week-old male Fischer-344 rats for 14d. Although the magnitude of abnormality was highest in kidney of rats fed the -M diet, the damage was normalized as the dietary level of Mg increased, with increasing serum Mg concentration and urinary excretion of Mg. We found almost no deposition of Ca in rats fed the 10M diet. The mechanism by which the high dietary Mg induces these effects most likely involves a competition between Mg and Ca for reabsorption in proximal and/or distal tubules, since these diets increased the urinary excretion of Ca. However, these high Mg diets decreased food intake and body weight gain compared with the control diet, although these indices were not decreased in rats fed the 2M diet. The results suggest that a dietary magnesium level approximately twice the normal level effectively reduces kidney calcification while maintaining normal growth in rats.

Resistant proteins alter cecal short-chain fatty acid profiles in rats fed high amylose cornstarch

The objective of this study was to examine the physiologic importance of undigested protein on cecal fermentation in rats fed a low (LAS) and high (HAS) amylose cornstarch. In Experiment 1, rats were fed diets containing LAS (655 g/kg diet) with one of four protein sources: casein, rice (RP), potato (PP) or soybean protein (SP) at 250 g/kg diet for 15 d. Apparent digestibilities of casein, RP, SP and PP were 96, 94, 93 and 92%, respectively. In rats fed the LAS diet with casein, acetate, propionate and succinate were the major cecal organic acids. The succinate pools in rats fed RP or SP were significantly lower than in those fed casein, whereas butyrate did not differ. Butyrate was significantly higher in rats fed PP, but succinate was the same as in rats fed casein. In Experiment 2, rats were fed diets containing HAS (200 g/kg diet) with one of the four protein sources at 250 g/kg diet for 10 d. HAS was substituted for the same amount of LAS. In rats fed the HAS diet, succinate was the major acid in rats fed casein; in rats fed RP or PP, however, the pools of this acid were significantly lower than in those fed casein, whereas butyrate was significantly higher in rats fed RP or PP. Fecal starch excretion was significantly lower in rats fed RP or PP than in those fed casein. In Experiment 3, rats were fed the casein-HAS diet with graded levels of PP (0, 10, 30, 50, 100 and 250 g/kg diet) for 14 d. The PP was substituted for the same amount of casein. Cecal butyrate was low in rats fed up to 100 g of PP/kg diet and then rose with 250 g of PP/kg diet. In Experiment 4, ileorectostomized rats were used and fed the same diets described in Experiment 3 for 9 d. The ileal starch/nitrogen ratio declined with increasing dietary PP, due solely to greater nitrogen excretion, whereas starch excretion was unaffected. In Experiment 5, rats were fed the casein-HAS diet with or without 60 g of artificial resistant protein/kg diet for 10 d. The resistant protein (apparent digestibility, 63%) was substituted for the same amount of casein. Rats fed the casein-HAS diet with resistant protein had significantly greater cecal butyrate and lower succinate than those fed the casein-HAS diet. These data show that large bowel fermentation of starch is altered by dietary protein. They support the hypothesis that nondigested protein, namely, resistant protein, may control fermentation efficiency as well as the fermentation profile of HAS, possibly as a result of a change in microflora through the change in the ratio of starch to nitrogen in the cecum.

Comparison of the sheath delivery system versus bare stenting for coronary stent implantation

Outside the United States, Palmaz-Schatz coronary stents are implanted by hand-crimping the stent to a high pressure balloon without the use of a protective sheath. This lowers the delivery profile, increases the ease of deployment, and ensures that the postdilatation balloon is centered on the stent. To assess this bare stenting technique, 209 patients were retrospectively analyzed: 92 patients (107 lesions) with the sheath protected stent delivery system (SDS) and 117 patients (150 lesions) with the bare stent approach. The number of balloons used per lesion in the bare stent group was significantly less than in the SDS group (1.9 +/- 0.6 vs. 3.8 +/- 1.2, P < 0.0001). In addition, the procedure time in the bare stent group was significantly shorter than in the SDS group (106 +/- 55 vs. 134 +/- 60 min, P = 0.001). There was no difference in frequency of adverse events or stent displacement during the procedure. The bare stenting technique decreases the procedure time, reduces the number of balloons used, and is as safe as the SDS approach.

Video networking of cardiac catheterization laboratories

A video telecommunication network was established to transmit coronary images between a cardiac catheterization laboratory and a remote core laboratory. In 40 patients during interventional procedures, cine angiograms, live fluoroscopy, intravascular ultrasound studies, and images of the cath lab were transmitted in real time over a T1 line at 768 kbits/second at 15 frames/second.

RESULTS

Measurements of angiographic and intravascular ultrasound parameters were very close between the original studies and the transmitted images. The telecommunication link up during the interventional procedures had a significant affect in 58% of cases.

Effect of coronary risk factors on coronary angiographic morphology in patients with ischemic heart disease

We investigated the effects of hypercholesterolemia, hypertension, and diabetes mellitus, which are major coronary risk factors, on the angiographic morphology of coronary artery lesions in 204 patients with previous myocardial infarction or stable-effort angina: 39 patients with hypercholesterolemia (serum total cholesterol > 240 mg/dl) without hypertension and diabetes, 51 patients with hypertension without diabetes and hypercholesterolemia, 24 patients with diabetes without hypertension and hypercholesterolemia, and 90 patients without any of these 3 risk factors (control). Patients without coronary artery lesions were excluded. The severity of coronary artery lesions is expressed as the Gensini score and the morphology is classified according to Rosch's classification. The distribution of coronary artery lesions did not differ significantly between the 4 groups. The Gensini score was significantly higher in the hypercholesterolemia group than in the other groups (p < 0.05). Short concentric lesions were more frequent in the hypercholesterolemia group than in the control group (p < 0.01), and tubular regular lesions were more frequent in the hypertension and diabetes groups than in the control group (p < 0.01). These results suggest that hypercholesterolemia has a greater influence on the severity of coronary artery lesions than does hypertension or diabetes, and that the progression of coronary atherosclerosis may differ among patients with these risk factors.

Cholesterol-lowering effects of soybean, potato and rice proteins depend on their low methionine contents in rats fed a cholesterol-free purified diet

Rats were fed cholesterol-free purified diets containing casein, rice (RP), potato (PP) or soybean (SP) proteins having different amounts of methionine (25.9, 21.3, 16.2 and 10.9 g methionine/kg, respectively). Each protein was fed at 250 g/kg diet for 14 d. Growth rates of rats were the same in all groups. Serum total cholesterol concentrations were lower in rats fed SP, PP and RP than in those fed casein. Fecal bile acid plus neutral steroid excretion was significantly higher in rats fed the RP, PP and SP diets compared with those fed casein. There was a significant negative correlation between serum cholesterol concentration and fecal total steroid excretion (r = -0.490, P = 0.01). However, a stronger positive correlation was observed between serum cholesterol concentration and dietary methionine concentration (r = 0.674, P = 0.0003) or methionine:glycine ratios (r = 0.656, P = 0.0005). In a separate experiment in rats fed diets containing amino acid mixtures simulating the RP, PP and SP diets, serum total cholesterol concentrations were lower than in rats fed simulated casein. Fecal total steroid excretion was the same in all groups. A strong correlation was found between serum cholesterol concentration and dietary methionine concentration (r = 0.743, P = 0.0002) or the methionine:glycine ratio (r = 0.685, P = 0.0009) in rats fed the amino acid mixtures. Finally, we examined the hypocholesterolemic effects of 250 g SP or casein/kg diet with or without supplementation with 0.3 g/100 g sodium taurocholate (TC). Supplementation with TC did not alter the hypocholesterolemic effect of SP. These results support the view that RP, PP and SP lower serum cholesterol concentration in a similar manner.

Diastolic plateau wave of pulmonary artery pressure in severe congestive heart failure

We describe 3 cases of severe congestive heart failure. The patients exhibited a marked decrease in transmitral flow velocity during atrial contraction and an abnormal diastolic plateau wave of pulmonary artery pressure (PAP). The first patient was a 60-year-old man with acute myocardial infarction and acute renal failure in whom pulmonary capillary wedge pressure (PCWP) was raised to 20 mmHg. Pulsed Doppler echocardiography revealed a marked decrease in transmitral flow velocity during atrial contraction, and the PAP waveform showed a mid to late diastolic plateau wave. Treatment for congestive heart failure reduced PCWP to 10 mmHg and the PAP waveform returned to normal. Doppler examination revealed the normal transmitral flow velocity pattern. The second patient was a 37-year-old woman with subarachnoid hemorrhage and the third patient a 74-year-old man with acute myocardial infarction. In these patients, the PAP waveform also showed a diastolic plateau wave, which was abolished by treatment. We believe that the diastolic plateau wave of PAP indicates left ventricular diastolic dysfunction and marked elevation of left ventricular filling pressure.

Effect of intravenous magnesium sulfate on cardiac arrhythmias in critically ill patients with low serum ionized magnesium

Magnesium affects cardiac function, although until the recent development of a new ion-selective electrode no method existed for measuring the physiologically active form of magnesium, free ions (iMg2+), in the blood. We investigated the antiarrhythmic effect of magnesium sulfate administered to critically ill patients with cardiac arrhythmias and reduced iMg2+ as determined using the ion-selective electrode. Eight patients with a low iMg2+ level (less than 0.40 mmol/L) were given intravenous magnesium sulfate (group L). Magnesium sulfate was also administered to patients with a normal iMg2+ level (more than 0.40 mmol/L) but who did not respond to conventional antiarrhythmic drugs (group N). Intravenous magnesium sulfate significantly increased the iMg2+ level in patients in group L from 0.35 +/- 0.06 mmol/L (mean +/- SD) to 0.54 +/- 0.09 mmol/L (p < 0.01), and had an antiarrhythmic effect in 7 of the 8 patients (88%). However, in group N patients, intravenous magnesium sulfate had an antiarrhythmic effect in only 1 of the 6 patients (17%) (p < 0.05 vs group L). These results suggest that intravenous magnesium sulfate may be effective in the acute management of cardiac arrhythmias in patients with a low serum iMg2+ level.