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This study confirms that botulinum neurotoxin type A (BoNT-A) decreases capsular contracture and elucidates a possible mechanism. Silicone blocks were implanted subcutaneously in 20 mice. The experimental groups received BoNT-A (1, 2·5 or 5 U) instilled into the subcutaneous pocket. After 30 days, periprosthetic capsules were harvested and evaluated. The effect of BoNT-A on the differentiation of human dermal fibroblasts to myofibroblasts in culture was examined by Western blot analysis. Changes in transforming growth factor-beta1 (TGF-β1) expression in cultured fibroblasts were determined by enzyme-linked immunosorbent assay (ELISA). In in vivo study, the thickness of capsules (P < 0·05) and the number of alpha-smooth muscle actin (α-SMA)(+) cells in capsules (P < 0·05) were significantly decreased in the experimental groups. TGF-β1 was significantly underexpressed in the experimental groups (P < 0·05). In in vitro study, BoNT-A did not significantly affect fibroblast viability. Western blot analysis showed that α-SMA protein levels were significantly decreased in the experimental groups (P < 0·05). Based on ELISA, the amount of TGF-β1 was significantly decreased in the experimental groups (P < 0·05), especially cells treated with a high dose of BoNT-A (P < 0·001). This study confirms that BoNT-A prevents capsular formation around silicone implants, possibly by blocking TGF-β1 signalling and interrupting the differentiation of fibroblasts to myofibroblasts.

Selective absorption of isoprene from n-pentane mixtures was performed via reversible π complexation with an aqueous solution of copper(I) nitrate, which was prepared by the disproportionation reaction between copper powder and cupric nitrate trihydrate [Cu(NO3)2·3H2O] in H2O in the presence of pyridine and nitric acid as stabilizers. The absorption of isoprene by the Cu(I) solution increased with an increase in the molar ratio of isoprene/Cu(I) up to 1 and remained nearly constant thereafter. The maximum isoprene pickup achieved at the molar ratio of isoprene/Cu(I) = 1 was around 0.5 equiv of Cu(I), implying that isoprene was complexed with Cu(I) in a η2 mode. The absorption ability of the Cu(I) solution was strongly dependent on the concentrations of the stabilizers, which prevent the oxidation of Cu(I) to Cu(II). The optimal molar composition of the solution was found to be Cu(I)/pyridine/HNO3 = 1/2.7/1.

UNLABELLED Because perfluorocarbon (PFC) liquid contacts closely with the alveolar capillaries during partial liquid ventilation (PLV), PLV with cold PFC may be used for the induction of hypothermia. Twenty rabbits were randomized to PFC-induced hypothermia (PH) (n = 7; core temperature 35 degrees +/- 1 degrees C), surface hypothermia (SH) (n = 7; 35 degrees +/- 1 degrees C), or normothermia (n = 6; 39 degrees +/- 1 degrees C). We induced PH by repeated in situ exchanges of 0 degrees C perfluorodecalin during PLV. At the establishment (0 min) of hypothermia in the PH group, oxygen consumption (P = 0.04) and oxygen extraction ratio (P = 0.01) decreased from normothermic condition. Metabolic (oxygen consumption, oxygen extraction ratio, serum lactate level) and hemodynamic variables (heart rate, blood pressure, cardiac output, pulmonary artery pressure) of the PH group were not different from those of the SH group at 0, 30, 60, 90, and 120 min of hypothermia. The difference in temperature between the pulmonary artery and rectum during the hypothermic period was smaller in the PH group compared with the SH group (P = 0.033). In conclusion, hypothermia may be induced during PLV by using cold PFC. This "pulmonary method" of cooling was comparable to a systemic method of cooling with regard to a few important physiologic variables, while maintaining a narrower interorgan temperature difference. IMPLICATIONS The induction of moderate hypothermia was feasible in rabbits by administrating cold perfluorocarbon liquid into the lung. Physiologic changes induced by this pulmonary cooling were comparable to those induced by systemic cooling. Our method may be regarded as a methodological advance in the field of therapeutic hypothermia.

The pharmacokinetics of M1, M2, M3, and/or M4 were compared after intravenous (iv) administration of DA-125 and/or ME2303 to mice (25 mg kg−1) and rats (5, 10, 20, 30, and 40 mg kg−1). The mean plasma concentrations of M1 were detected up to 8 h after iv administration of both DA-125 and ME2303 to mice, and were significantly higher for DA-125 than ME2303; this resulted in a considerably greater AUC (303 against 148 μg min mL−1) and a considerably slower CL of M1 (69·3 against 136 mL min−1 kg−1) after iv administration of DA-125. The MRT (371 against 189 min) and CLNR of M1 (68·7 against 136 mL min−1 kg−1) were considerably greater and slower, respectively, after iv administration of DA-125. The mean plasma concentrations of M2 were detected up to 8 and 4 h after iv administration of DA-125 and ME2303, respectively, to mice and were significantly higher for DA-125 than ME2303, resulting in a considerably greater AUC of M2 (148 against 27·1 μg min mL−1) after iv administration of DA-125. The mean plasma concentrations of M3, being the lowest among M1–M4, were detected only up to 15 min after iv administration of both DA-125 and ME2303 to mice, and were comparable after iv adminstration of DA-125 and ME2303 to mice. The mean plasma concentrations of M4 were detected up to 8 h after iv administration of both DA-125 and ME2303 to mice, and were higher after iv administration of DA-125 than ME2303, resulting in a considerably greater AUC of M4 (197 against 61·9 μg min mL−1) after iv administration of DA-125. Similar results on M1 and M2 were also obtained from rats: the mean plasma concentrations of both M1 and M2 were significantly higher after iv administration of DA-125, 10 mg kg−1, than after ME2303. The plasma concentrations of M1, M2, and M4, and hence their AUCs, were significantly higher after iv administration of DA-125, 5, 10, 20, 30, and 40 mg kg−1, to rats than after ME2303: the mean plasma concentrations of M2, approximately 0·1–0·4 μg mL−1, were maintained from 30 min to 8–10 h after iv administration of DA-125, 20, 30, and 40 mg kg−1, to rats; the plasma concentrations of M3 were the lowest among M1–M4 at all DA-125 doses; and those of M1 and M4 were maintained for a long period of time. However, after iv administration of M2, 5 mg kg−1, to rats, the mean plasma concentrations of M2 were detected up to 60 min with a mean terminal half-life of only 38·8 min, and the concentrations of M3 were negligible. After iv administration of M3, 5 mg kg−1, to rats, the mean plasma concentrations of M3 were detected up to 15 min; the plasma concentrations of M4, reaching their peak at 5 min, decayed more slowly and were higher than those of M3. The AUC of M4 after iv administration of M3, 5 mg kg−1, was comparable to that after iv administration of M4, 5 mg kg−1, to rats, suggesting that M4 is formed fast and almost completely from M3. M1 was not detected in plasma after iv administration of either M2 or M3 to rats. After iv administration of M4, 5 mg kg−1, to rats, the mean plasma concentrations of M4 decayed fast with a mean terminal half-life of 43·9 min and neither M2 nor M3 were detected in plasma. The following disposition mechanisms for M1, M2, M3, and M4 after iv administration of DA-125 to rats could be obtained from the above data: (i) the maintenance of plasma concentrations of M2 for a longer period of time after iv administration of DA-125 than those after iv administration of M2 could be due to the continuous formation of M2 from M1; (ii) the lowest plasma concentrations of M3 among M1–M4 after iv administration of DA-125 could be due to the fast and almost complete formation of M4 from M3 as soon as M3 is formed from M1, and not due to the fast renal excretion of unchanged M3; (iii) M4 was exclusively and continuously formed from M3 and the formation of M4 from M2 was negligible; and (iv) reversible metabolism among M1–M4 did not take place. The following results could also be obtained after iv administration of DA-125 or ME2303 to mice and rats: (i) the lower plasma concentrations of M1 after iv administration of ME2303 than of DA-125 could be due to the greater biliary excretion of unchanged ME2303 (approximately 30% of iv dose) than unchanged DA-125 and (ii) the lower plasma concentrations of M2 and M4 after iv administration of ME2303 than after DA-125 could be due to lower plasma concentrations of M1 and hence less formation of both M2 and M4 from M1. Liver showed the highest metabolic activity for M1 and a considerable amount of M1 was also metabolized in the kidney after 30 min incubation of 50 μg of DA-125 in 9000 g supernatant fraction of rat tissue homogenates. The mean amount of M1 remaining per gram of tissue, the total amount of M1 remaining in whole tissue, and the tissue to plasma ratio of M1 were significantly higher in the heart, lung, large intestine, and kidney at 15 min after iv administration of DA-125, 25 mg kg−1, to mice than after ME2303. M1, the active antineoplastic moiety of DA-125, had higher affinity for the lung after iv administration of DA-125 to mice than after ME2303, indicating that lung tumours could be subjected to a greater exposure to M1 after iv administration of DA-125 than ME2303. The 24 h biliary excretion of M1 was significantly greater after the iv administration of ME2303 than after DA-125 (344 against 79·3 μg). However, reversed results were obtained for M2 (267 against 467 μg). M3 and M4 were under the detection limit in the bile sample after iv administration of either DA-125 or ME2303.

The pharmacokinetics of DA-125 were compared after intravenous (i.v.) administration of the drug, 10 mg kg-1, to control male Sprague-Dawley rats (n = 9) and uranyl nitrate-induced acute renal failure (U-ARF, n = 12) rats, or male Sprague-Dawley rats fed on a 23% (control, n = 8) or a 5% (protein-calorie malnutrition, PCM, n = 9) protein diet. After i.v. administration of DA-125, almost 'constant' plasma concentrations of M1, M2, and M4 were maintained from 1-2 h to 8-10 h in all rat groups due to the continuous formation of M2 from M1 and M4 from M3. The plasma concentrations of M3 were the lowest among M1-M4 for all rat groups due to the rapid and almost complete conversion of M3 to M4 and other metabolite(s). The AUCt values of M1 (115 against 82.5 micrograms min mL-1), M2 (33.0 against 23.6 micrograms min mL-1), and M4 (26.3 against 15.1 micrograms min mL-1) were significantly higher in the U-ARF rats than in the control rats. The percentages of i.v. dose excreted in 24 h urine as M1 (under the detection limit against 0.316%), M2 (under the detection limit against 5.58%), and M4 (0.0174 against 0.719%)--expressed in terms of DA-125--were significantly lower in the U-ARF rats than in the control rats, and this could be due to the decreased kidney function in the U-ARF rats. However, the percentages of i.v. dose recovered from the GI tract at 24 h as M1 (0.0532% against under the detection limit), M3 (0.0286% against under the detection limit), and M4 (0.702% against 0.305%)--expressed in terms of DA-125--were significantly greater in the U-ARF rats than in the control rats. All U-ARF rats had ascites, but the concentrations of M1 (0.0320 micrograms mL-1), M2 (0.0265 micrograms mL-1), M3 (under the detection limit), and M4 (0.032 micrograms mL-1) in the ascites from one rat were almost negligible. The plasma concentrations and most of the pharmacokinetic parameters of M1, M2, and M4 were not significantly different between the PCM rats and their control rats.

The pharmacokinetics and tissue distribution of M1-M4 were compared after intravenous (i.v.) administration of DA-125, 25 mg kg-1, to BDF1 mice (n = 5 at each sampling time) and subcutaneously implanted Lewis-lung-carcinoma-bearing BDF1 mice (n = 10 at each sampling time. The mean plasma concentrations of M1-M4 were not significantly different between the two groups of mice, and hence similar pharmacokinetic parameters for M1-M4 were obtained. The amount of M1 in the lung was significantly greater in the tumour-bearing mice than in the control mice, resulting in a greater AUAt in the tumour-bearing mice (18,600 against 8940 micrograms min g-1), and vice versa in the liver (962 against 3840 micrograms min g-1). However, the corresponding values for other tissues were comparable between the control and tumour-bearing mice. The amount of M1 was greatest in the lung for up to 2 h in the tumour-bearing mice. M2 was the predominant metabolite among M1-M4 excreted in 24 h urine by both groups of mice; 8.36 and 10.7% of the i.v. dose were excreted in 24 h urine as M2--expressed in terms of DA-125--by the control and tumour-bearing mice, respectively. The amount of M1 in the tumour mass reached a mean Cmax of 3.75 micrograms g-1 immediately after i.v. administration of DA-125 to the tumour-bearing mice, then declined very slowly to an amount that remained almost constant for up to 24 h. This suggested that M1 has high affinity for the subcutaneously implanted Lewis lung carcinoma. The antitumour activity, such as the increase in life span (ILS) and tumour growth inhibition (TGI) of DA-125, 6-48 mg kg-1, and adriamycin (ADM), 3-18 mg kg-1, were also compared in subcutaneously implanted Lewis-lung-carcinoma-bearing BDF1 mice after four weekly i.v. administration of the drugs on days 1,8,15, and 22 following tumour implantation. More than three out of six mice survived as tumour-free for longer than 70 d at a DA-125 dose range of 6-24 mg kg-1, but there were no tumour-free mice at any dose of ADM. Assuming ILS values higher than 30% to be effective, DA-125 doses ranging from 6 to 24 mg kg-1 were effective in increasing the life span, which ADM does only within the dose range of 6-12 mg kg-1.

The pharmacokinetic parameters, tissue distribution and biliary excretion of M1-M4 were estimated after intravenous (i.v.) administration of DA-125, 2.5 mg per kg to beagle dogs. The mean values of the terminal half-life, mean residence time, total body clearance and apparent volume of distribution at steady state of M1 were 266 min, 170 min, 61.3 ml min −1 kg −1 and 9500 ml kg −1 , respectively (four male and four female dogs). M1 was highly concentrated in lung (five male and five female dogs), and this probably means that lung tumors are subjected to greater exposure to M1, an active metabolite of DA-125. The 8 h biliary excretion of M2 was significantly greater than that of M1, 53.6 vs 6860 μg (three male and two female dogs). The amount of glucuronide and/or sulfate conjugates of M1-M4 in the bile sample was negligible.

The pharmacokinetics of DA-125 or its active metabolite, M1 (FT-ADM), an adriamycin analog containing fluorine were compared after intravenous (i.v.) administration of DA-125 or M1 in rats. DA-125, 20 mg kg−1 was dissolved in 1 mM lactic acid/0.9% NaCl solution (treatment I) or 100% dimethylsulfoxide (DMSO, treatment II), and M1, 20 mgkg was dissolved in 100% DMSO (treatment III) due to its poor water solubility. The plasma concentrations of DA-125 and M1, and the pharmacokinetic parameters of DA-125, such as terminal half-life (t12, 1.64 vs 2.07 min), mean residence time (MRT, 1.52 vs 2.60 min), total body clearance (CL, 165 vs 186 ml min−1 kg−1) and apparent volume of distribution at steady state (Vdss, 254 vs 411 ml kg−1), and of M1 (based on plasma data up to 1 h), such as (t12 (30.2 vs 38.7 min), MRT (19.1 vs 31.6 min), CL (187 vs 189 ml min−1 kg−1) and Vdss(2670vs 5700 ml kg−1were similar between treatments I and II, indicating that the effect of 100% DMSO on the pharmacokinetics of DA-125 or M1 seemed to be negligible, if any. The plasma concentrations of M1, and the pharmacokinetic parameters of M1 (based on plasma data up to 8 h when the dose of M1, 20 mg kg−1 was normalized to the dose of DA-125, 20 mg kg−1), such as (t12 (255 vs 221 min), MRT (269 vs 235 min), CL (103 vs 112 ml min−1 kg−1) and Vdss (28 500 vs 26300 ml kg−1) were also similar between treatments II and III. The above results indicate that DA-125 is rapidly hydrolyzed to M1 after i.v. administration of DA-125. Therefore, the estimation of the pharmacokinetic parameters of M1 after i.v. administra- tion of DA-125 appeared not to cause any differences, if any when compared with the values after i.v. dose of M1. The rapid hydrolysis of DA-125 to M1 was demonstrated during an in vitro study; the (t12 values of hydrolysis of DA-125 were 1.97, 1.72, 0.54 and 0.54 min in the plasma from mouse, rat, dog and human, respectively, when the plasma containing DA-125 was incubated in a shaking water bath kept at 37°C and at a rate of 300 rpm.