Nonlinear pharmacokinetics of hepatobiliary transport of rose bengal in rats after i.v. bolus administration with varying doses

To investigate the nonlinear kinetics in the hepatobiliary transport of rose bengal (RB), the time profiles of plasma concentration and biliary excretion rate after its i.v. administration at various doses were measured in rats. The total body clearance decreased remarkably with increased dose. The hepatic uptake clearance also showed a similar dose dependency, and saturation of hepatic uptake at least partly accounts for the dose-dependent change in total body clearance. The peak biliary excretion rate approached the transport maximum (approximately 150 nmol min-1 kg-1) with increased dose. To further clarify which process in RB hepatobiliary transport has nonlinearity, we analysed thus obtained data based on a three-compartment model. The hepatic uptake and sequestration rate constants decreased remarkably with increased dose. The initial hepatic uptake rates assessed from the plasma disappearance rate during the early phase fit well to the Michaelis-Menten equation with a saturable and a nonsaturable component. The maximum uptake velocity and Michaelis constant were 4.7 mumol min-1 kg-1 and 360 microM, respectively. That hepatic uptake has a much higher capacity (about 30 fold) than biliary excretion suggests that biliary excretion can be a rate-determining process in the overall hepatobiliary transport of RB. We conclude that the saturation of both hepatic uptake and biliary excretion could be the main causes for the nonlinear pharmacokinetics of hepatobiliary transport of RB.

Kinetic modeling of ouabain tissue distribution based on slow and saturable binding to Na,K-ATPase

The significance of the binding to Na,K-ATPase in the tissue distribution of ouabain was previously documented (Harashima et al., Pharm. Res. 9:474-479, 1992). The purpose of this study was to obtain a kinetic model of ouabain tissue distribution. In most tissues, the ouabain concentration continued to rise after the termination of infusion (5 min), with the peak tissue concentration at approximately 20 min. This delay could not be explained by the rapid equilibrium model (RE model), nor could the kinetics of ouabain be explained by an RE model modified for saturable binding. Since ouabain binding to Na,K-ATPase is slow, the association and dissociation processes were incorporated into a model that can accurately fit the observed time courses of ouabain. The obtained binding parameters corresponded well with the observed values in the in vitro binding experiments, except for muscle. These results quantitatively support the role of the slow and saturable binding of ouabain to Na,K-ATPase in its tissue distribution.

Marked increase in plasma interleukin-6 in burn patients

We measured the levels of interleukin-6 in plasma samples from 18 consecutive burn patients, including three lethal cases, during the early postburn period. In survivors burn injury caused initial increases in interleukin-6 levels that peaked at 6 hours after burn; this was significantly higher than interleukin-6 levels in normal controls (718 +/- 216 vs 70 +/- 4 pg/ml; p < 0.01). The increment in nonsurvivors was even more prominent (11,554 +/- 4,407 pg/ml; p < 0.01). The peak interleukin-6 levels at 6 hours correlated with total burn surface area (r = 0.65, p < 0.025), and tended to be higher in patients with inhalation injury. These data provide evidence that burn injury causes rapid release of interleukin-6 according to the severity of the injury. We also measured acute-phase reactants including fibrinogen, alpha 1-antitrypsin, C1 inhibitor, and alpha 2-plasmin inhibitor. After initial declines, these four proteins increased rapidly in survivors. In addition, the peak interleukin-6 levels correlated well with the increases in fibrinogen (p < 0.025), alpha 1-antitrypsin (p < 0.01), C1 inhibitor (p < 0.01), and alpha 2-plasmin inhibitor (p < 0.0001). In contrast, despite the marked increase in interleukin-6, the levels of acute phase proteins in nonsurvivors remained low. Based on these observations, we suggest that interleukin-6 is released as an alarm signal and has a role for the wound healing in burn patients, and that the levels of interleukin-6 after injury is an indicator of the severity of burn.

Hydration and occlusion treatment for hypertrophic scars and keloids

In 31 patients with hypertrophic scars or keloids, a side by side test was carried out to check the efficacy of an occlusive dressing technique using cream which did not contain silicone oil, versus a simple application of vaseline, used as a control. In all cases, the cream treated areas of scar and keloid demonstrated a remarkable improvement over that of the vaseline treated area. These findings strongly suggest that the mechanisms of hydration and occlusion are the main basis of the therapeutic action of this method in treating hypertrophic scars and keloids.

Comparison of coronary responses to intracoronary and intraaortic ergonovine and isosorbide dinitrate in patients with atypical chest pain

Fifty patients with atypical chest pain were studied to compare coronary responses to intracoronary and intraaortic ergonovine. The diameters of the proximal, middle (1) and (2) (proximal segments of segments 2 and 3 [AHA classification], respectively), and distal segments of the right coronary artery were measured before and after intracoronary ergonovine (4 micrograms/minute over 4 minutes) and isosorbide dinitrate (ISDN) (2 mg) in 24 patients, and before and after intraaortic ergonovine (0.2 mg) and ISDN (5 mg) in 26. Mean vasoconstriction by intracoronary and intraaortic ergonovine were 13 +/- 1.5% and 9 +/- 0.8%, respectively (p < 0.02). Irrespective of the methods of administration, the responses to ergonovine were similar in the 4 segments. Mean vasodilation by intracoronary and intraaortic ISDN, which were used to quantify the degree of basal coronary tone, were 25 +/- 2.2% and 27 +/- 1.5%, respectively (p = not significant [NS]). There were significant negative linear correlations between the responses to ergonovine and ISDN in the middle (2) (r = -0.51; p < 0.05) and distal (r = -0.53; p < 0.01) segments in patients with intracoronary injection, and the proximal (r = -0.41; p < 0.05), middle (1) (r = -0.66; p < 0.01) and middle (2) (r = -0.69; p < 0.01) segments in patients with intraaortic injection. These observations indicate that low-dose administration of intracoronary ergonovine produces sufficient coronary vasoconstriction, similar to or slightly greater than that of intraaortic ergonovine in patients with atypical chest pain, but basal coronary tone may influence the vasoreactivity to ergonovine.

Pharmacokinetic profile of glycyrrhizin in healthy volunteers by a new high-performance liquid chromatographic method

An improved high-performance liquid chromatographic method was developed for the quantification of glycyrrhizin and its metabolites in human plasma. The improved method was selective and made it possible to determine precisely glycyrrhizin at levels as low as 500 ng/mL. The pharmacokinetic behavior of glycyrrhizin and its metabolites after oral and intravenous administration of glycyrrhizin to normal subjects was investigated. After oral administration of glycyrrhizin (100 mg) to three normal subjects, the major metabolite of glycyrrhizin (glycyrrhetic acid) appeared in plasma (less than 200 ng/mL), but glycyrrhizin was not found. On the other hand, glycyrrhizin was found in urine, and the amount excreted was 1.1-2.5% of the dose. This finding suggests that glycyrrhizin is partly absorbed in the intact form from the gastrointestinal tract. The concentration of glycyrrhizin in plasma after intravenous administration of glycyrrhizin (40, 80, and 120 mg) showed biexponential profiles during the 24-h period after administration of each dose. The glycyrrhizin metabolites, glycyrrhetic acid and glycyrrhetic acid-3-O-glucuronide, were not detected in either plasma or urine. The terminal half-life of glycyrrhizin, the apparent volume of the central compartment, the steady-state distribution volume, and the total body clearance in three dosing experiments were 2.7-4.8 h, 37-64 mL/kg, 59-98 mL/kg, and 16-25 mL/kg/h, respectively. Glycyrrhizin was not detected in plasma after oral administration of the usual therapeutic dose of glycyrrhizin, and no dose dependency of the drug was observed in the dose range of 40-120 mg.

A technique of haemostasis of the extremities after debridement of burn wounds

A technique used to achieve prompt haemostasis in burned wounds of the extremities is described. After tangential debridement using a tourniquet, thrombin solution (1000 units in 1 ml of saline solution) is applied on the entire wound. Immediately after removing the tourniquet; the wound is tightly wrapped with a thin plastic film and a pressure bandage over the entire wound. The pressure bandage is kept on for approximately 10 min after removing the tourniquet. With this procedure, haemostasis of the capillary oozing can be promptly and completely achieved. Furthermore, arterial and venous haemostasis can also be achieved, with clots present at the arterial and venous haemorrhagic points. As these clots can be removed easily, ligation or electrocoagulation is necessary. This technique is especially useful for haemostasis in a wound of the extremity after tangential excision leading to decreasing blood loss.

The effect of continuous topical application of heparin on flap survival

To evaluate the beneficial effects of heparin on flap survival area, an experimental study was carried out on dorsal flaps in rats. Topical applications of heparin, released from a silicone gel sheet onto the critical area (which generally necrosed without treatment), resulted in an increase in the flap survival area and rate as compared to controls (p < 0.01). When heparin was applied topically but solely to an area proximal to the critical area however, no increase in the survival area resulted.

A nasal vestibular flap for reconstruction of the upper lip

A technique to reconstruct the hair-bearing upper lip by means of a hair-loaded nasal vestibular flap is described. This flap is elevated from the nasal vestibular area, and does not result in nasal deformity. This flap is especially suitable to reconstruct the medial portion of the hair-bearing upper lip in adult males.

Existence of two pathways for the endocytosis of epidermal growth factor by rat liver: phenylarsine oxide-sensitive and -insensitive pathways

The effect of phenylarsine oxide (PAO) on the internalization rate of epidermal growth factor (EGF) was investigated using perfused rat liver and isolated rat hepatocytes. In perfused liver, a tracer concentration of 125I-EGF alone or with excess unlabeled EGF (20 nM) was perfused and the internalization rate constants (kint) were measured. In the absence of PAO, kint values did not differ significantly for either dose condition. However, with the addition of PAO to the perfusate, the kint value dropped to 4% of that of the control at the low concentration of EGF, while dropping to only 40% of that of the control at the high concentration of EGF. These results suggest the existence of a PAO-insensitive internalization pathway having a kint value comparable with that of the other pathway. Similar EGF concentration-dependent inhibition of 125I-EGF internalization caused by PAO was ascertained using isolated rat hepatocytes. PAO also decreased the cellular ATP content in isolated hepatocytes. However, when we lowered the cellular ATP content with rotenone, the cell-surface binding and internalization of EGF were comparable with the control levels. We concluded that there exist dual pathways for the internalization of EGF and that excess doses of EGF lead to EGF internalization not only through a PAO-sensitive pathway but also through a PAO-insensitive pathway, whereas at a tracer dose of EGF, the internalization occurs mainly via the PAO-sensitive pathway.

Postremission therapy without prednisolone improves survival in adults with acute leukemia

This prospective randomized clinical trial was to clarify whether postremission therapy without prednisolone (PSL) was more effective than therapy with PSL in improving the 5-year survival of adults with acute leukemia. Thirty consecutive adult patients with newly achieved complete remission were randomized to receive postremission therapy either with or without PSL between September 1985 and September 1988. The patients ranged from 16 to 57 years in age. Patients treated without PSL had a significantly better 5-year survival rate than those receiving PSL according to Kaplan-Meier analysis (53.5% vs 15.3%, p < 0.05). In the group treated without PSL, eight out of 15 patients were alive at 72 months, and seven patients maintained their first complete remission at 72 months. Among patients with acute lymphoblastic leukemia (ALL) who were treated without PSL the median duration of remission was 24 months, and the survival rate at 72 months was 50.0%. On the other hand, the median survival was only 13 months for the 5 patients with ALL treated with PSL. Thus, it is desirable that adults with acute leukemia are treated by postremission therapy without PSL.

'Albumin-mediated transport phenomenon' observed for ligands with high membrane permeability. Effect of the unstirred water layer in the Disse's space of rat liver

In this paper, we offer experimental evidence of the rate-limiting diffusion of ligands through the unstirred water layer (UWL) as an explanation for the so-called albumin-mediated transport phenomenon. The relative membrane permeability of various ligands was first evaluated using isolated rat hepatocytes. Then, the effect of albumin on the uptake of ligands of a wide range of membrane permeabilities was examined using the perfused rat liver. The results were similar to those expected from the UWL model: ligands with high membrane permeability (warfarin, diazepam and taurocholate) clearly exhibited albumin-mediated transport, those with medium membrane permeability (tolbutamide and salicylate) showed less albumin-mediated transport, and ligand with low membrane permeability (cefodizime) did not show albumin-mediated transport. These results were explained by simulation studies of two separate cases based on the UWL model; one assuming the rapid equilibrium of ligand binding with albumin, and the other considering the slow dissociation of ligands from albumin. In light of these findings, we suggest that the rate-limiting diffusion through the UWL plays an important role in the so-called albumin-mediated transport phenomenon.

Lactimidomycin, a new glutarimide group antibiotic. Production, isolation, structure and biological activity

Streptomyces amphibiosporus R310-104 (ATCC 53964) produced a novel antibiotic lactimidomycin which showed inhibitory activity against fungi and prolonged the survival time of mice transplanted with experimental tumors. Structural studies clarified that lactimidomycin is a new glutarimide antibiotic having a unique unsaturated 12-membered lactone ring.

Correlation between the inhibitory effects of basic drugs on the uptake of cardiac glycosides and taurocholate by isolated rat hepatocytes

The role of the multispecific bile acid transporter for cardiac glycoside uptake is still controversial. This study was designed to examine the inhibitory effects of basic drugs (verapamil, dipyridamole, nifedipine, chlorpromazine, disopyramide, quinidine, propranolol, and lidocaine) on taurocholate uptake by isolated rat hepatocytes and to compare these effects with inhibition of ouabain uptake. Sodium-dependent taurocholate uptake was significantly reduced, to 50-70% of the control value, by 50 microM verapamil, dipyridamole, and nifedipine. Sodium-independent taurocholate uptake was more extensively inhibited, to 20-40%, by these basic drugs. The inhibition of ouabain uptake correlated better with sodium-independent taurocholate uptake (gamma = 0.918) than with sodium-dependent taurocholate uptake (gamma = 0.714). Taurocholate competitively inhibited ouabain uptake in the absence of sodium. These results indicate that the cardiac glycoside transport system is similar to the sodium-independent taurocholate transport system.

Kinetic analysis of hepatobiliary transport of vincristine in perfused rat liver. Possible roles of P-glycoprotein in biliary excretion of vincristine

Recent studies using bile canalicular membrane vesicles have suggested that P-glycoprotein may play a role in excreting some anticancer drugs from the liver to the bile. At steady state after a continuous single-pass perfusion of a tracer concentration of [3H]vincristine in the rat liver, the extraction ratio was approximately 0.6, and 70% of the extracted drug was excreted into the bile mostly in unchanged form. The liver/perfusate and bile/liver unbound concentration ratios obtained after correction for intracellular binding and the inside-negative membrane potentials and/or pH difference between the inside and outside of the cells, were approximately 2-3 and 160-280, respectively, suggesting a highly concentrated biliary excretion process. We also examined the effects of verapamil, a P-glycoprotein-related transport inhibitor in cancer cells, on the hepatobiliary transport of [3H]vincristine. Verapamil 50 microM in the perfusate caused a decrease in the biliary excretion rate of [3H]vincristine, whereas [14C]taurocholate (reference compound) remained constant. In contrast, the hepatic uptake rate of [3H]vincristine exhibited minimum reduction, suggesting that verapamil selectively inhibited the biliary excretion of [3H]vincristine at the canalicular membrane. The fact that verapamil had little effect on the initial velocity of [3H]vincristine uptake by isolated hepatocytes also supports the above findings. Since the effect of 150 microM verapamil in the perfusate was not selective for vincristine, the biliary excretion rates of both compounds ([3H]vincristine, [14C]taurocholate) were reduced by this concentration of verapamil. In conclusion, the concentrative excretion of vincristine into the bile and its selective inhibition by a moderate concentration of verapamil provide indirect evidence for the contribution of P-glycoprotein to the biliary excretion of vincristine in a perfused rat liver system.

The relationship between prostaglandin E1 applied area and flap survival rate

Using a silicone gel sheet continuous drug delivery system containing Prostaglandin E1 (PGE1), the relationship between flap survival rate and the site of drug application was studied. Skin flaps measuring 2 x 9 cm were raised on the dorsum of rats, and divided into 3 areas. Area 1 was within 3 cm of the flap tip, area 2 was between 3-6 cm from the flap tip including the critical zone, and area 3 was the portion within 4 cm of the flap base. Further, area 4 was a strip of skin around the flap, 1 cm in width. Compared to the control group, a significant increase in flap survival rate was seen only when PGE1 was administered to area 2 (p < 0.01, t-test). Specimens injected with dye intravascularly showed an increase in the number of thick vessels in area 3, when PGE1 was applied only to area 3. However, when PGE1 was applied to area 2, there was no significant vascular increase in area 3. Instead, an extensive network of fine vessels was observed in area 2.

Sultriecin, a new antifungal and antitumor antibiotic from Streptomyces roseiscleroticus. Production, isolation, structure and biological activity

Streptomyces roseiscleroticus L827-7 (ATCC 53903) produced a novel antifungal and antitumor antibiotic, sultriecin. It exhibited in vitro antifungal activity and potent in vivo antitumor activity against P388 and L1210 leukemias, and B16 melanoma. Sultriecin is composed of several unique structural units; a conjugated triene, an alpha,beta-unsaturated delta-lactone, and a sulfate functionality.

[The results and problems of reoperation for coronary artery disease]

In six hundred and six consecutive patients undergoing coronary artery bypass grafting (CABG) within the past 17 years (May 1974 to March 1991), repeated CABG were performed on 10 patients (1.65%). The main reasons for repeated CABG were graft failure (GF) in 8, progression of native disease (NP) in 5 and incomplete revascularization (IR) in 3 patients. The incidence of GF was high either within a half year or around 5 years after CABG. Although all patients survived from reoperation, four patients continued to have mild angina pectoris. When the recurrence of angina is noted after CABG, coronary arteriography and if necessary PTCA should be done as soon as possible. If a second surgery is inevitable, maximum utilization of arterial graft and accomplishment of complete revascularization are emphasized.

[Favorable prognoses in 24 adult patients with acute leukemia, surviving over five years since 1985]

Since 1985 we have experienced 24 leukemia cases with long-term survival, who were treated with one of three types of postremission therapy. Of them, 20 patients were physically fit for ordinary work and returned to their work as workers or housewives during long-term follow-up period. Two housewives gave birth. We have devised three types of postremission therapy; 1) multidrug combination therapy with gradually longer intermissions (January 1980-March 1983); 2) controlled randomized clinical trial by the Japanese Foundation for the Multidisciplinary Treatment of Cancer, April 1983-March 1985-March 1988). In a group who underwent multidrug combination therapy without prednisolone, 12 of 20 patients who achieved complete remission have shown continued complete remission, as of November 1991, including seven 5-year survivors. These results indicate that improvement of postremission therapy makes it possible for adult patients with acute leukemia to survive 5 years or longer.

The Kaike triathletes' hematocrit values. With relation to their competition results

The subjects were 20 male triathletes in the 4th Kaike Triathlon, held in Tottori during 1984. The competitors' hemogram values were estimated at rest, during, and after the competition. The results were related to their competition order by methods of rank correlations and cluster analysis, using the average distance method. The first cluster, including an competition order is composed of hematocrit at rest, after swimming, after bicycling, and after the finish. The rank correlation coefficients between competition order and hematocrit values were significant (p less than 0.05) at each of the four periods, especially after swimming, though the probability is the same. We found that lower hematocrit values correlate with excellent competition results, as the competitors' hematocrit values could be elevated during exercise if their hematocrit values are in the low normal density whilst at rest.

Prevention of dressing slippage under an elastic bandage

A technique is described to prevent the shift in position of dressing materials by applying a double-sided adhesive tape between the skin and the elastic bandage. This technique also prevents a shift in position of a pressure garment, especially when applied around joints on the extremities.

Development of nitrate tolerance and usefulness of pulse therapy in a patient with vasospastic angina

In a 58-year-old man with vasospastic angina, we investigated the relationship between the antianginal effects of isosorbide dinitrate (ISDN) and plasma ISDN concentration. Despite adequate plasma ISDN levels, sustained therapy using ISDN tapes and oral ISDN (transcutaneously 160 mg and orally 100 mg ISDN day-1) failed to exhibit antianginal effects. However, pulse therapy using sublingual short-acting ISDN prevented anginal episodes, although the plasma ISDN levels were less than those of sustained therapy. Nitrate tolerance of the antianginal effects was avoided by creating an abrupt plasma ISDN concentration gradient using sublingual ISDN.

[A case of retrovesical fibrosarcoma with severe hypoglycemia]

We report a case of retrovesical fibrosarcoma with severe hypoglycemia. A 67-year-old man was admitted to our hospital with second recurrence of the retrovesical tumor with hypoglycemia. The episodes of hypoglycemia were accompanied by the advance of tumor size. Complete tumor resection with total cystectomy was performed on December 21, 1989, and the tumor was diagnosed histopathologically as fibrosarcoma. Soon after removal of the tumor, hypoglycemia disappeared and the patient has been well without local recurrence or distant metastasis for more than 20 months.