Potentiation of the chemotherapeutic action of 5′-deoxy-5-fluorouridine in combination with guanosine and related compounds

Summary The effect of inosine, guanosine, and guanosine 5-monophosphate (GMP) on the antitumor activity of 5-deoxy-5-fluorouridine (5-DFUR) was investigated using P388 leukemia and P815 mastocytoma.The antitumor activity of 5-DFUR was markedly enhanced by coadministration of inosine or guanosine. The increase in lifespan (ILS) of mice treated with 5-DFUR was augmented by the combination with guanosine or inosine in a dose-dependent fashion, and the maximum ILS was about 160% with the combination, while that in the case of 5-DFUR alone was only 48% in the P388 leukemia system. The therapeutic ratio (dose at ILS_max/dose at ILS₃₀) of the combination with guanosine or inosine was 333 and 136, respectively, whereas that of 5-DFUR alone was 3.6. GMP also markedly potentiated the antitumor activity of 5-DFUR in both P388 leukemia and P815 mastocytoma systems, just as it potentiated the activity of 5-fluorouracil in the latter system.The uric acid level in the serum was elevated after IP injection of guanosine or inosine but the value was much lower in the case of guanosine than in inosine.     

Acute renal dysfunction by cadmium injected with cysteine in relation to renal critical concentration of cadmium

In order to study the critical concentration of cadmium (Cd) in acute renal dysfunction following Cd, male mice were injected IV with Cd complexed with cysteine. The critical concentration was 10 g Cd/g wet weight in whole kidney and it was the same as that for Cdthionein (Cd-Th), which may suggest that the toxicity of Cd-Th is due to Cd ions liberated from Cd-Th in the kidneys. Renal Cd concentration was at first higher than the critical concentration, but decreased to the critical concentration by 24 h after administration. As an index for renal dysfunction, the uptake of p-aminohippurate (PAH) by renal cortical slices in vitro was sensitive, and showed the different time-course from those of urinary protein and glucose levels. The results suggest the usefulness of PAH uptake as an index. Incidental to the renal dysfunction, renal calcium levels exhibited a marked increase.     

Phase I clinical and pharmacokinetic study ofN 4-behenoyl-1-β-d-arabinofuranosylcytosine

A phase I study ofN ⁴-behenoyl-1-β-d-arabinofuranosylcytosine (BHAC) was conducted in 66 patients, 41 with solid tumors and 25 with hematological malignancies. The patients received either a 2-h single intravenous (i.v.) drip infusion (Schedule 1) or consecutive daily 2-h i.v. infusions (Schedule 2). In Schedule 1 the daily dose was initiated with 1.5 mg kg^?1 which was escalated up to 7 mg kg^?1. Side-effects were mild, and included nausea, vomiting, epilation, and hot flushes. Because of the presence of the solvent vehicle, HCO-60 and in consideration of the mechanism of action of BHAC, the dose escalation was stopped at 7 mg kg^?1. In Schedule 2, the daily dose was started with 1.5 mg kg^?1 which was escalated up to 8 mg kg^?1 and given for 2–16 days. Myelosuppression was found to be dose-limiting toxicity. The maximum tolerated dose (MTD) in patients with non-hematological solid tumors was assumed to be 5 mg kg^?1 daily × 5 days. The plasma disappearance curve of BHAC looked biphasic, and when 4 mg kg^?1 of BHAC were administered the half-lives of the initial phase (t _1/2α) and the second phase (t _1/2β) were calculated as 0.798 and 5.76 h respectively. In Schedule 2 complete remission was observed in 5 out of 21 patients with acute leukemia, one partial remission in Hodgkin’s disease, and one 1-B response (Karnofsky) in thyroid papillary adenocarcinoma.     

Effects of Fucoxanthin on the Inhibition of Dexamethasone-Induced Skeletal Muscle Loss in Mice

Fucoxanthin (Fx) has preventive effect against muscle atrophy and myotube loss in vitro, but it has not yet been examined in vivo. Therefore, we aimed to investigate the effect of Fx on dexamethasone (Dex)-induced muscle atrophy and fat mass in mice. ICR mice were fed with Fx diets from 2 weeks before Dex treatment to the end of the study. Muscle atrophy was induced in the mice by oral administration of Dex. Body weight was significantly lower by Dex treatment. Visceral fat mass in the Fx-treated group were significantly lower than those in the control group. The Dex-induced decrease in tibialis anterior muscle mass was ameliorated by Fx treatment. Fx treatment significantly attenuated muscle lipid peroxidation compared with the control and Dex-treated groups. The phosphorylation of AMPK was significantly higher in the Dex-treated group than in the control group. The expression of cytochrome c oxidase (COX) IV was significantly higher in the Fx-treated group than in the control group. These results suggest that Fx may be a beneficial material to prevent muscle atrophy in vivo, in addition to the effect of fat loss.     

Dose-response relation and time course of

The dose-response relation of pipecuronium, the time course of its neuromuscular blocking effects, and the reversibility of the residual block by neostigmine have been investigated in patients under sevoflurane/N₂O Anesthesia using a neuromuscular transmission analyzer (Accelograph^®, Biometer, Denmark). After an initial dose of pipecuronium (0.04mg·kg^–1, i.v.), the maximum block rate, onset time, the time from administration until 25% recovery and 50% recovery of control twitch height of the first response to train-of-four nerve stimulation and the interval time of administration of maintenance dose (0.005mg·kg^–1, i.v.) were 93.7 ± 7.68%, 5.0 ± 1.84, 55.4 ± 23.92, 73.0 ± 29.44 and 38.7 ± 15.50 minutes, respectively. The average intubation score (excellent; 0, good; 1 fair; 2, poor; 3) was 0.63 ± 0.56 at the level of 95.88 ± 5.06% block. Neostigmine (1.5mg) promptly reversed the residual neuromuscular blockade induced by pipecuronium (reversal time: 10.1 ± 2.98 minutes). No side effects attributable to pipecuronium was seen in this study.In conclusion, pipecuronium is a very useful nondepolarizing neuromuscular blocking agent especially for moderately long surgical procedure over 4–5 hours.(Ueda N, Masuda Y, Muteki T, et al.: Does-response relation and time course of action of pipecuronium in patients anesthetized with nitrous oxide and sevoflurane. J Anesth 7: 151–156, 1993)     

Accumulation of L-[2-(F-18)]fluorophenylalanine in peri-infarct area in a patient with acute cerebral infarction

We studied the brain uptake of amino acid in a patient with acute cerebral infarction with L-[2-(F-18)] fluorophenylalanine and positron emission tomography. The increased accumulation of the ligand was specifically found in the peri-infarct area where oxygen metabolism was still maintained but decreased later in the 72-day follow-up period. The kinetic analysis revealed that increased accumulation was not due to increased transport from the blood to the brain but to delayed washout from the brain to the blood. Although the mechanism is still unknown, abnormally high accumulation of L-[F-18]fluorophenylalanine may predict delayed neuronal changes after ischemic insults of the brain.     

A case with breast cancer under the nipple who underwent breast conserving treatment

Although breast conserving treatment (BCT) has become the standard therapy for early breast cancer, breast removal is still recommended for patients with a tumor beneath the nipple or with Paget’s disease. We have employed transposition of a latissimus dorsi myocutaneous (LD-MC) flap after wide local excision of a tumor with the nipple-areola complex. A new nipple-areola complex was reconstructed on the LD-MC flap after breast irradiation. Utilizing reconstructive techniques, BCT will likely become the treatment of choice for more patients with early breast cancer.     

Increase in choroidal blood flow in rabbits with endothelin-1 induced transient complete obstruction of retinal vessels

Background: In a previous paper, we reported that retinal blood flow (RBF) ceased immediately after injection of 1 nmol endothelin-1 (ET-1) and no recovery of RBF was detected for at least 50 min. In this study, we confirmed the same duration of RBF cessation and measured choroidal blood flow (CBF) for 180 min. Methods: We measured CBF in a rabbit model of transient complete obstruction of retinal vessels induced by intravitreal injection of a high dose of ET-1, using the hydrogen clearance method. We also investigated the effects of intravitreal injection of ET-1 on intraocular pressure (IOP), blood pressure, pulse rate and blood gases. Results: CBF was significantly greater in the ET-1-injected eyes than in the control eyes 40–130 min after injection of ET-1 (P < 0.05). The maximal CBF ratio in the ET-1-injected eyes was 128 ± 7.4% at 40 min. CBF decreased to the pre-injection level at 140 min after the injection of ET-1. There was no significant change in blood pressure, pulse rate and blood gases throughout this experiment, and there was no significant difference in IOP between ET-1-injected eyes and control eyes. Conclusion: It seems likely that the increase in CBF resulted from some local mechanisms of control that compensated for the decrease in RBF induced by intravitreal injection of ET-1. This model may be useful for investigation of the regulatory system of intraocular circulation, including endothelin receptors.