Autologous adipose tissue-derived stem cells for the treatment of complex perianal fistulas not associated with Crohn's disease: a phase II clinical trial for safety and efficacy.

PURPOSE: Injection of adipose tissue-derived stem cells (ASCs) is a novel method for the treatment of complex perianal fistulas. We aimed to evaluate the safety and efficacy of ASCs in the treatment of complex anal fistulas not associated with Crohn's disease. METHODS: A phase II clinical trial was performed comparing two different doses of ASCs (group 1: 1 × 107 cells/mL and group 2: 2 × 107 cells/mL). Eligible patients were administered an amount of ASCs proportional to the length of the fistula by injection into the submucosal layer surrounding the internal opening and inside of the fistula tract. ASCs at twice the initial concentration were administered if complete closure was not achieved within 8 weeks. The efficacy endpoint was the complete closure of fistulas 8 weeks after injection. Patients demonstrating complete closure at week 8 were subjected to follow-up for 6 months. RESULTS: Fifteen patients were injected with ASCs; thirteen completed the study. Complete closure was observed in 69.2% (9/13) of patients at 8 weeks. Three of five patients in group 1, and six of eight in group 2 displayed complete closure; no significant differences were observed between the groups. Six of nine patients who showed complete closure participated in additional follow-up; five (83.3%) showed persistent response at 6 months. No grade 3 or 4 adverse events (AEs) were observed; observed AEs were not related to ASC treatment. CONCLUSION: ASCs might be a good option for the treatment of complex perianal fistulas are not healed by conventional operative procedures.

Newborn hearing screening in prematurity: fate of screening failures and auditory maturation.

OBJECTIVES: The purpose of this study was to identify delayed auditory maturation and the fate of premature infants who failed the newborn hearing screening (NHS) in neonatal intensive care unit. MATERIALS AND METHODS: A total of 1375 neonates underwent NHS using the transient evoked otoacoustic emission (TEOAE) in a tertiary hospital between 2007 and 2010 according to the Joint Committee on Infant Hearing guidelines. In addition, a structured telephone survey was given to caregivers of infants who were lost to follow-up NHS. Auditory steady-state response (ASSR) threshold and the threshold change in diagnostic test failures were analysed. RESULT: Among the 1375 NICU babies, 344 (25.0%) babies, 111 (9.7%) babies and 64 (4.6%) babies failed to pass the first TEOAE, second TEOAE and diagnostic ASSR, respectively. However, at the age of about 5 years, 12 (0.9%) infants showed permanent hearing loss (PHL). The ASSR threshold improved from 69.0 ± 19.7 dB to 52.9 ± 21.6 dB in <4 months (P < 0.001). Premature infants of <29 weeks of gestational age at birth showed higher referral (P = 0.003) rate at the first OAE test compared to the others, and the difference continued until the last follow-up. The odds ratio for the initial ASSR threshold >67.5 dB for PHL was 9.00 (95% confidence interval, 1.7-46.7). CONCLUSION: Most of first TEOAE screening failures (91.3%) showed normal hearing and speech development. Hearing levels in premature infants can improve over time, particularly in neonates with initial ASSR threshold <67.5 dB.

Effectiveness of anatomic criteria for predicting parotid tumour location.

OBJECTIVE: We evaluated the accuracy, positive predictive value (PPV), negative predictive value (NPV), specificity and sensitivity of eight anatomic landmarks to differentiate parotid deep lobe tumours from superficial lobe tumours: the lateral margin of the retromandibular vein (RMV), a straight line from the facial nerve trunk (FN trunk) to the mandibular ramus (FN line), a straight line from the FN trunk to the RMV (tRMV), a straight line from the FN trunk to the lateral margin of the masseter (tMasseter), a straight line from the ipsilateral vertebral posterior end to the RMV (U-line), an arc with a radius of 8.5 mm centred on the mandibular ramus (Conn's arc), a straight line from the lateral surface of the masseter muscle to the lateral margin of the RMV (rMasseter) and an angle from the FN line, tumour and the lateral margin of the masseter muscle (FTM angle). METHODS: A total of 181 patients with a parotid gland tumour who underwent parotidectomy at a tertiary hospital were identified retrospectively from May 2005 to May 2013. Pre-operative computed tomography and intraoperative findings were compared to evaluate each landmark. RESULTS: rMasseter (accuracy: 85.5%, PPV: 90.0%, NPV: 85.12%, specificity: 98.1%, sensitivity: 22.2%) and tMasseter (accuracy: 86.3%, PPV: 80.0%, NPV: 87.1%, specificity: 97.1%, sensitivity: 44.4%) showed superior results as diagnostic criteria. CONCLUSION: rMasseter and tMasseter were useful as anatomic landmarks to differentiate a parotid deep lobe tumour from a superficial lobe tumour.

Endoscopic submucosal dissection or transanal endoscopic microsurgery for nonpolypoid rectal high grade dysplasia and submucosa-invading rectal cancer.

BACKGROUND AND STUDY AIMS: Transanal endoscopic microsurgery (TEM) has been shown to be highly effective for early rectal cancer, and endoscopic submucosal dissection (ESD) has been introduced to treat noninvasive colorectal neoplasia. The aim of this study was to compare the outcomes of ESD and TEM for superficial early rectal cancer. PATIENTS AND METHODS: We retrospectively analyzed 63 patients with nonpolypoid rectal high grade dysplasia or submucosa-invading cancer who were treated with ESD or TEM, and compared clinical outcomes and safety between the treatment groups. RESULTS: 30 patients underwent ESD and 33 underwent TEM. For ESD compared with TEM, en bloc resection rates were 96.7% vs. 100% (P = 0.476) and R0 resection rates were 96.7 % vs. 97.0 % (P = 1.000). There were no cases of local recurrence or distant metastasis in either group. Antibiotics were required in 11 patients (36.7%) in the ESD group and 33 (100%) in the TEM group (P < 0.001). There was no difference in net procedure time although ESD was associated with shorter total procedure time and hospital stay than TEM, with mean (standard deviation [SD]) 84.0 (51.2) vs. 116.4 (58.5) min (P = 0.0023), and 3.6 (1.2) vs. 6.6 (3.5) days (P < 0.001), respectively. There were no significant differences in complications between the two groups. CONCLUSIONS: Both ESD and TEM are effective and oncologically safe for treating nonpolypoid rectal high grade dysplasia and submucosa-invading cancers. ESD has the additional advantages of minimal invasiveness and avoidance of anesthesia. Therefore, ESD could be recommended as a treatment option for superficial early rectal cancers.

Double primary malignancy in colorectal cancer patients--MSI is the useful marker for predicting double primary tumors.

BACKGROUND AND AIMS: The incidence of double primary malignancies (DPM) is known to be higher in colorectal cancer patients than the general population. And, the role of microsatellite instability (MSI) in DPM has been previously studied. We evaluated the clinical features and association between MSI and colorectal cancer patients with DPM. MATERIALS AND METHODS: From September 1994 to May 2004, we reviewed 2,301 colorectal cancer patients with regard to secondary primary malignancies. A subgroup analysis was performed for MSI after January 2003. RESULTS: One hundred forty-five patients (6.3%) had a DPM identified. In DPM group, 57 patients had a synchronous DPM (39.3%), and 88 patients had a metachronous malignancy (60.7%). Male gender (p<0.001) and colon cancer (p<0.001) were the factors related with the development of the DPM. Most of the second malignancies occurred within 3 years after the primary operation. The common second malignancies were stomach (58 patients, 40%) and lung (21 patients, 14.5%). In the subgroup analysis, there was a higher frequency of DPM in the MSI group when compared to the microsatellite stable group (p=0.021). CONCLUSIONS: The careful pre- and postoperative evaluation should be paid for detecting DPM as well as for detecting recurrence in colorectal cancer patients. The results of this study suggest that MSI might be a useful marker for the detection of DPM in colorectal cancer patients.

Geometric calibration of a mobile C-arm for intraoperative cone-beam CT.

A geometric calibration method that determines a complete description of source-detector geometry was adapted to a mobile C-arm for cone-beam computed tomography (CBCT). The non-iterative calibration algorithm calculates a unique solution for the positions of the source (X(s), Y(s), Z(s)), detector (X(d), Y(d), Z(d)), piercing point (U(o), V(o)), and detector rotation angles (phi, theta, eta) based on projections of a phantom consisting of two plane-parallel circles of ball bearings encased in a cylindrical acrylic tube. The prototype C-arm system was based on a Siemens PowerMobil modified to provide flat-panel CBCT for image-guided interventions. The magnitude of geometric nonidealities in the source-detector orbit was measured, and the short-term (approximately 4 h) and long-term (approximately 6 months) reproducibility of the calibration was evaluated. The C-arm exhibits large geometric nonidealities due to mechanical flex, with maximum departures from the average semicircular orbit of deltaU(o) = 15.8 mm and deltaV(o) = 9.8 mm (for the piercing point), deltaX and deltaY = 6-8 mm and deltaZ = 1 mm (for the source and detector), and deltaphi approximately 2.9 degrees, deltatheta approximately 1.9 degrees, and delta eta approximately 0.8 degrees (for the detector tilt/rotation). Despite such significant departures from a semicircular orbit, these system parameters were found to be reproducible, and therefore correctable by geometric calibration. Short-term reproducibility was < 0.16 mm (subpixel) for the piercing point coordinates, < 0.25 mm for the source-detector X and Y, < 0.035 mm for the source-detector Z, and < 0.02 degrees for the detector angles. Long-term reproducibility was similarly high, demonstrated by image quality and spatial resolution measurements over a period of 6 months. For example, the full-width at half-maximum (FWHM) in axial images of a thin steel wire increased slightly as a function of the time (delta) between calibration and image acquisition: FWHM=0.62, 0.63, 0.66, 0.71, and 0.72 mm at delta = 0 s, 1 h, 1 day, 1 month, and 6 months, respectively. For ongoing clinical trials in CBCT-guided surgery at our institution, geometric calibration is conducted monthly to provide sufficient three-dimensional (3D) image quality while managing time and workflow considerations of the calibration and quality assurance process. The sensitivity of 3D image quality to each of the system parameters was investigated, as was the tolerance to systematic and random errors in the geometric parameters, showing the most sensitive parameters to be the piercing point coordinates (U(o), V(o)) and in-plane positions of the source (X(s), Y(s)) and detector (X(d), Y(d)). Errors in the out-of-plane position of the source (Z(s)) and detector (Z(d)) and the detector angles (phi, theta, eta) were shown to have subtler effects on 3D image quality.

Multiphasic contrast injection for improved precision of parameter estimates in functional CT.

Contrast injection protocol is known to affect the estimation of kinetic parameters in functional CT. A novel method is proposed to maximize the precision of parameter estimates by modulating the contrast injection scheme. The method models the intravenous contrast bolus to be dispersed by a "patient function" to give rise to the arterial input function, which, in turn, carries the contrast agent to tissue leading to contrast enhancement. The covariance matrix analysis was applied to calculate the uncertainty of parameter estimates as the coefficients of variation (CV) in the adiabatic tissue homogeneity (ATH), two-compartment, and the modified Kety model in which tumor pathophysiology is modeled. An optimization scheme was used to determine the optimal injection protocol which would minimize the CV of a particular kinetic parameter. For clinical utility, a recommended injection protocol was suggested from a statistical analysis with the optimal injection protocols obtained from the first group of 12 patients with cervix cancer. The efficacy of the recommended injection protocol was tested with a second group of 12 patients. In addition, the robustness of the recommended injection protocol to longitudinal study has been investigated in the presence of variations in arterial input function and tumor pathophysiology. Based on the data of the second group of patients, and using the ATH model, the recommended biphasic injection of two boluses improves the precision in the estimation of blood flow and mean transit time (MTT), by 36.9% and 38.4%, respectively, compared to the standard uniphasic injection protocol in the CV. However, measurement of the permeability surface area product and extravascular extracellular space volume favors a single fast bolus of the same contrast amount. The two-compartment model and the modified Kety model also benefited from the single fast bolus. The effect of variation in the arterial input function and tumor pathophysiology on the applicability of the recommended injection was also investigated. Based on computer simulation for a range of variations in the arterial input function and pathophysiology, the recommended biphasic injection was found to improve the precision in blood flow and MTT estimates by 31.4% and 36.5% on average, respectively, compared to the uniphasic injection.

A novel four-dimensional radiotherapy method for lung cancer: imaging, treatment planning and delivery.

We present treatment planning methods based on four-dimensional computed tomography (4D-CT) to incorporate tumour motion using (1) a static field and (2) a dynamic field. Static 4D fields are determined to include the target in all breathing phases, whereas dynamic 4D fields are determined to follow the shape of the tumour assessed from 4D-CT images with a dynamic weighting factor. The weighting factor selection depends on the reliability of patient breathing and limitations of the delivery system. The static 4D method is compared with our standard protocol for gross tumour volume (GTV) coverage, mean lung dose and V20. It was found that the GTV delineated on helical CT without incorporating breathing motion does not adequately represent the target compared to the GTV delineated from 4D-CT. Dosimetric analysis indicates that the static 4D-CT based technique results in a reduction of the mean lung dose compared with the standard protocol. Measurements on a moving phantom and simulations indicated that 4D radiotherapy (4D-RT) synchronized with respiration-induced motion further reduces mean lung dose and V20, and may allow safe application of dose escalation and CRT/IMRT. The motions of the chest cavity, tumour and thoracic structures of 24 lung cancer patients are also analysed.

Synthesis and antitumor activity of a series of [2-substituted-4,5-bis(aminomethyl)-1,3-dioxolane]platinum(II) complexes.

The synthesis, physical properties, antitumor activity, structure-activity relationships, and nephrotoxicity of a series of [2-substituted-4,5-bis(aminomethyl)-1,3-dioxolane]platinum(II) complexes are described. The 42 platinum(II) complexes having a seven-membered ring structure in this series have been prepared and characterized by 1H NMR, 13C NMR, IR, FAB-MS, and elemental analysis. All members of the series were designed to have a 1,3-dioxolane ring moiety in their carrier ligands to increase water solubility. The solubility of platinum complexes was related to the nature of leaving ligands and 2-substituents in the 4,5-bis(aminomethyl)-1,3-dioxolane carrier ligands. In general, compounds having two different R1 and R2 substituents in the 4,5-bis(aminomethyl)-1,3-dioxolane moiety were more water-soluble than those having the same substituents. Most members of this series showed the excellent antitumor activity against murine L1210 leukemia cells transplanted in mice and were superior to cisplatin and carboplatin. The (4R,5R)-stereoisomer 1a-h exhibited the higher antitumor activity than the corresponding (4S,5S)-stereoisomer 2a-h in the (1,1-cyclobutanedicarboxylato)platinum(II) complexes. The (glycolato)-platinum(II) complexes were highly cytotoxic toward four human stomach cancer cell lines, SNU-1, SNU-5, SNU-16, and NCI-N87, and among them, complexes 3d-g were even more cytotoxic than cisplatin. The (malonato)platinum(II) complex 1m and the (glycolato)platinum(II) complexes 3d-g were selected for further studies based on the greater in vivo and in vitro antitumor activity and desirable physical properties. The complexes 3e-g were almost equally cytotoxic to cisplatin toward human stomach cancer cell lines, KATO-III and MKN-45, and a human non-small cell lung cancer cell line, PC14. In contrast with cisplatin and carboplatin, five complexes selected significantly increased in life span in mice transplanted with cisplatin-resistant L1210 cells. Nephrotoxicity studies in ICR mice indicated that serum BUN and creatinine levels were not elevated when five complexes were given at a dose equal to 1.5 times the optimal dose determined in the in vivo L1210 screening system.

Synthesis and evaluation of 2-amino-9-(3-hydroxymethyl-4-alkoxycarbonyloxybut-1-yl)purines as potential prodrugs of penciclovir.

A series of 2-amino-9-(3-hydroxymethyl-4-alkoxycarbonyloxybut-1-yl)purines (4-10) and 2-amino-9-(2-(2-oxo-1,3-dioxan-5-yl)ethyl)purine (1) were synthesized as potential prodrugs of penciclovir and evaluated for their oral penciclovir bioavailability in mice and rats. Treatment of 2-(2-benzyloxyethyl)propane-1,3-diol (11) with 1,1'-carbonyldiimidazole in THF followed by hydrogenolytic removal of the benzyl group of the resulting cyclic carbonate 12 gave 5-(2-hydroxyethyl)-1,3-dioxan-2-one (13). Mesylation of the alcohol 13 and then a coupling reaction of the resulting mesylate 14 with 2-amino-6-chloropurine using anhydrous Cs2CO3 in DMF afforded 2-amino-6-chloro-9-(2-(2-oxo-1,3-dioxan-5-yl)ethyl)purine (16) after purification by flash column chromatography on silica gel using EtOAc/MeCN/Et3N as eluent. Hydrogenation of the 6-chloro cyclic carbonate 16 followed by a ring-opening reaction of the 6-deoxy cyclic carbonate 1 in a mixture of an appropriate alcohol and CHCl3 using activated SiO2 as a Lewis acid afforded the corresponding alkyl monocarbonate derivatives 3-10 in fair to good yields. Of the prodrugs tested in mice, the isopropyl monocarbonate 6 achieved the highest mean urinary recovery of penciclovir (53%), followed in order by the propyl monocarbonate 5 (51%), the isopentyl monocarbonate 10 (51%), the ethyl monocarbonate 4 (50%), and famciclovir (48%). In rats, the methyl monocarbonate 3, 4, 6, the n-butyl monocarbonate 7, and 10 (39-41%) showed levels of mean urinary recovery of penciclovir similar to that from famciclovir (40%). The alkyl monocarbonates 4-10 were found to be quite stable in the aqueous buffer solutions, and among them, 6 was the most stable with the half-lives (t1/2) of 88, >200, 61, and 26 days at pH 1.2, 6.0, 7.4, and 8.0, respectively. In addition, 6 was highly soluble in H2O (138.8 mg/mL, 20 degrees C).

Pharmacokinetic/pharmacodynamic evaluation of a novel potassium channel opener, SKP-450, in healthy volunteers.

To evaluate the pharmacokinetic/pharmacodynamic characteristics of SKP-450, a novel K+ channel opener, a single blind, randomized, placebo-controlled, dose-rising, parallel-group study was conducted in 28 healthy volunteers. The volunteers were randomly allocated to dosage groups of 50 micrograms, 100 micrograms, 200 micrograms, and 300 micrograms. Single doses of SKP-450 were administered orally, after overnight fasting, and serial blood sampling and pharmacodynamic measurements were performed up to 48 hours after the drug was administered. The 200 micrograms group was further studied for food interactions in a crossover fashion. Drug concentrations in plasma were determined by HPLC. Hemodynamic changes after drug administration were evaluated by serial measurements of blood pressure (BP), pulse rate (PR), cardiac index (CI), and total peripheral resistance (TPR), using computerized impedance cardiography. Changes in plasma renin activity (PRA) and aldosterone concentrations (PAC) were determined 4 and 24 hours after drug administration. Both SKP-450 and SKP-818, an active metabolite, showed linear pharmacokinetic characteristics, and food intake did not significantly affect the pharmacokinetic characteristics of either compound. Dose-related pharmacological effects were obvious for both the 200 micrograms and 300 micrograms groups. Hemodynamic parameters related to vasodilation and reflex tachycardia, such as maximum changes in diastolic BP, PR, CI, and TPR, showed significant dose-dependent changes. The area under the time-effect curve (AUEC) of the parameters also showed a similar dose-dependent pattern. The PRA and PAC exhibited significant changes 4 hours after drug administration in the 300 micrograms group. Adverse effects, such as headaches, were more frequently observed at the higher dose levels. SKP-450 was generally well tolerated by these normotensive subjects. The antihypertensive efficacy of SKP-450 needs to be evaluated in hypertensive patients after multiple dosing.

Pharmacokinetics and antitumor activity of a new platinum compound, cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3- dioxolane]platinum(II), as determined by ex vivo pharmacodynamics.

The pharmacokinetics and ex vivo pharmacodynamics studies on cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3- dioxolane]platinum(II) (SKI 2053R, NSC D644591), cisplatin (CDDP), and carboplatin (CBDCA) were performed in beagle dogs. Equitoxic doses of SKI 2053R, CDDP, and CBDCA (7.5, 2.5, and 15.0 mg/kg, respectively) were given by i.v. bolus to three beagle dogs in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the three drugs declined in a biexponential fashion. The mean area under the concentration-time curve (AUC0-->infinity) determined for ultrafiltrable platinum derived from SKI 2053R, as an active component, was 7.72 +/- 2.74 micrograms h ml-1 (mean +/- SD), with an initial half-life of 0.37 +/- 0.20 h, a terminal half-life of 2.19 +/- 0.93 h, a total clearance of 16.83 +/- 4.76 ml min-1 kg-1, and a steady-state volume of distribution of 1.57 +/- 0.30 l/kg. The ex vivo antitumor activity of SKI 2053R was assessed using the ultrafiltrable plasma against two human lung-adenocarcinoma cell lines (PC-9 and PC-14) and five stomach-adenocarcinoma cell lines (MKN-45, KATO III, SNU-1, SNU-5, and SNU-16) by tetrazolium-dye (MTT) assay and was compared with that of CDDP and CBDCA using an antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value was shown to be ranked in the following order: SKI 2053R > CBDCA > CDDP. The mean ATI values recorded for SKI 2053R and CBDCA were significantly (P < 0.05) higher than that noted for CDDP; however, no statistically significant difference was observed between SKI 2053R and CBDCA, suggesting that the antitumor activity of SKI 2053R is superior to that of CDDP and is equivalent to that of CBDCA. These results suggest that SKI 2053R is a promising candidate for further development as a clinically useful anticancer drug.

Antitumor activity of cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2- isopropyl-1,3-dioxolane]platinum(II), a new platinum analogue, as an anticancer agent.

The in vitro and in vivo antitumor activity of a new antitumor platinum complex, cis-malonato[(4R, 5R)-4,5- bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) (SKI2053R, NSC D644591), were evaluated and compared with those of cisplatin (CDDP) and carboplatin (CBDCA) using murine tumors. SKI 2053R was highly active in vitro against both L1210 murine leukemia and its CDDP-resistant subline, L1210/DDP; the relative resistances were 20.0-, 14.5-, and 2.7-fold for CDDP, CBDCA, and SKI 2053R, respectively. SKI 2053R showed activity comparable with or superior to either CDDP or CBDCA in mice implanted with L1210. In mice implanted with L1210/DDP, as compared with CBDCA, SKI 2053R showed high values for the percentage of treated survivors relative to controls and for numbers of cured mice, whereas CDDP had virtually no activity. In mice implanted with P388, all three drugs were highly active, but the intensity of activity was shown to be ranked in the following order: SKI 2053R > CDDP > CBDCA. The antitumor activity of SKI 2053R against Lewis lung carcinoma was comparable with that of both CDDP and CBDCA. The antitumor activity of SKI 2053R was further investigated against two human tumor xenografts, KATO III (stomach adenocarcinoma) and WiDr (colon adenocarcinoma), implanted s.c. in nude mice and was compared with that of CDDP. In SKI 2053R-treated groups, the time required for a mean tumor weight of 1,000 mg was 33.1 days in KATO III xenografts and 35.0 days in WiDr xenografts as compared with 30.2 and 27.2 days in CDDP-treated groups, respectively. SKI 2053R achieved growth-inhibition rates comparable with those of CDDP against KATO III (65% versus 59%) and WiDr xenografts (64% versus 54%) on day 35. These results indicate that SKI 2053R is an attractive candidate for further development as a clinically useful anticancer drug.

Influence of exposure and infusion times on the cytotoxicity and pharmacokinetics of cis-malonato[(4R, 5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]platinum(II) .

The effect of exposure time on the in vitro cytotoxicity of a new platinum complex, cis-malonato[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolan e]platinum(II) (SKI 2053R) and cisplatin (CDDP) toward two human lung-adenocarcinoma cell lines (PC-9, PC-14) and two human stomach-adenocarcinoma cell lines (KATO III, MKN-45) was investigated by variation of the exposure time (1, 4, 12, and 24 h) and drug concentration to yield a constant product of drug concentration times exposure time (C x T). Exposure of cancer cells to low concentrations of SKI 2053R for 12 or 24 h resulted in a greater killing effect than did 1- or 4-h exposure to 24- or 6-fold higher concentrations; the inhibitory effects of SKI 2053R on the colony formation of all tumor cell lines except for KATO III were significantly increased with increasing exposure time (P < 0.05). However, the inhibitory effects of CDDP against all tumor cell lines tested except for PC-14 were inversely correlated with increasing exposure time (P < 0.05). The intracellular accumulation of SKI 2053R and CDDP was measured under the same conditions used in the cell-survival assay using MKN-45 cells. The amount of platinum accumulated from SKI 2053R into MKN-45 cells was greater for the treatment involving low concentrations and long-term exposures (12 and 24 h) than for that using high concentrations and short-term exposures (1 and 4 h) at the constant C x T values; however, the increased accumulation of CDDP was more prominent as the concentration was increased, even if the exposure time became shorter. The pharmacokinetics studies of SKI 2053R following 1-, 4-, 12-, and 24-h infusions were performed in beagle dogs. A single dose of SKI 2053R (5.0 mg/kg) was successively given over various infusion periods to three beagle dogs at 3-week intervals. The peak levels of ultrafiltrable platinum observed for SKI 2053R at the 1-, 4-, 12-, and 24-h infusions were 3.10+/-0.49 (mean +/- SD), 1.24+/-0.06, 0.43+/-0.07, and 0.25+/-0.04 microg/ml, respectively. The mean binding ratios of platinum from SKI 2053R to plasma protein at the end of 1-, 4-, 12-, and 24-h infusions were approximately 91%, 73%, 53%, and 51%, respectively. The steady-state level of free platinum was maintained during long-term infusions (12 and 24 h) after short periods (1-3 h) from the start of the infusion. This study strongly suggests that the therapeutic efficacy of SKI 2053R given by continuous long-term infusion should be investigated in future clinical studies.

Pharmacokinetics of a new platinum compound, cis-(glycolato-O,O) [(4R,5R)-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'-cyclohexane]plat inum (II) in dogs.

A pharmacokinetic study on cis-(glycolato-O,O)/ (4R,5R)-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'- cyclohexane]platinum(II) (SKI 2032R) was performed in dogs. A single dose of 2.0 mg/kg of SKI 2032R was administered i.v. bolus to three beagle dogs. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for SKI 2032R declined in a biexponential fashion. The mean area under the concentration-time curve (AUC0 --> infinity) determined for ultrafiltrable platinum derived from SKI 2032R, as an active component, was 2.36 +/- 0.23 micrograms. h/ml (mean +/- S.D.), with an initial half-life of 0.23 +/- 0.20 hour, a terminal half-life of 1.32 +/- 0.49 hour, a total clearance of 14.17 +/- 1.50 ml/min/kg, and a steady-state volume of distribution of 1.21 +/- 0.24 l/kg.

Pharmacokinetics of platinum following the administration of cis-(glycolato-O,O')[(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1, 3-dioxolane]platinum(II) in dogs.

The pharmacokinetic study on cis-(glycolato-O,O') [(4R,5R)-4,5-bis(aminomethyl)-2-isopropyl-1,3-dioxolane]-platinum(II) (SKI 2034R, NSC D642489) was performed in beagle dogs. A single dose of 2.0 mg/kg of SKI 2034R was given by i.v. bolus to three beagle dogs. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for SKI 2034R declined in a biexponential fashion. The mean area under the concentration-time curve (AUC0-->infinity) determined for ultrafiltrable platinum derived from SKI 2034R, as an active component, was 2.76 +/- 0.13 micrograms.h/ml (mean +/- S.D.), with an initial half-life of 0.15 +/- 0.09 hour, a terminal half-life of 0.96 +/- 0.12 hour, a total clearance of 12.07 +/- 0.67 ml/min/kg, and a steady-state volume of distribution of 0.82 +/- 0.06 1/kg.

In vitro cytotoxicity, pharmacokinetics and ex vivo pharmacodynamics of a new platinum compound, cis-malonato [(4R,5R-4,5-bis(aminomethyl)-1,3-dioxolane-2-spiro-1'-cyclopentane] platinum (II).

The in vitro cytotoxicity of a new platinum complex, cis-malonato [(4R, 5R)-4,5-bis(aminomethyl)-1,3-dioxolane 2- spiro 1' cyclo-pentane]platinum(II) (SKI 2054R) and cisplatin (CDDP) was evaluated against two human stomach adenocarcinoma cell lines (MKN-45 and KATO III) and a human lung adenocarcinoma cell line (PC-14). The in vitro 50% inhibitory concentration (IC50) values of SKI 2054R and CDDP against MKN-45, KATO III, and PC-14 were 1.21 and 0.51, 2.11 and 0.83, and 2.90 and 0.77 micrograms/ml, respectively. The pharma-cokinetic and ex vivo pharmacodynamic studies on SKI 2054R and CDDP were performed in beagle dogs. Equitoxic doses of SKI 2054R and CDDP (7.0 and 3.0 mg/kg, respectively) were administered i.v. bolus to beagle dose in a randomized crossover study. Plasma samples were analyzed for platinum by flameless atomic absorption spectrophotometry. Plasma concentrations of total and ultrafiltrable platinum for the two drugs declined in a biexponential fashion. The mean area under the concentration-tine curve (AUC(0)--> infinity) determined for ultrafiltrable platinum derived from SKI 2054R, as an active component was 6.61 +/- 2.34 micrograms . h/ml (mean +/- S.D.), with an initial half-life of 0.26 +/- 0.14 h, a terminal half-life of 1.57 +/- 0.71 hour, a total clearance of 17.65 +/- 4.99 ml/min/kg, and a steady-state volume of distribution of 1.46 +/- 0.11 l/kg. The ex vivo antitumor activity of SKI 2054R was assessed using the ultrafiltrable plasma against MKN-45, KATO III, and PC-14 by tetrazolium-dye (MTT) assay and was compared with that of CDDP using the antitumor index (ATI) determined from the ex vivo pharmacodynamic results of inhibition rates (%) versus time curves. The mean ATI value recorded for SKI 2054R was higher than that noted for CDDP; however, statistical difference was not observed between SKI 2054R and CDDP, suggesting that the antitumor activity of SKI 2054R is comparable to that of CDDP. These results suggest that SKI 2054R is a new platinum complex which is worth being evaluated further.

Phase II trial of a novel platinum analog, SKI 2053R, in patients with previously untreated extensive-stage small-cell lung cancer.

A phase II trial of a novel platinum analog, SKI 2053R, was performed in patients with previously untreated extensive-stage disease (ED) small-cell lung cancer (SCLC). SKI 2053R was administered at the dose of 400 mg/m2 every 3 to 4 weeks as a 1-h infusion. After the first cycle, the dose was escalated to 440 mg/m2 based on toxicity. Thirty-eight patients (31 male) were enrolled between June 1995 and August 1997. The median age was 61 years (range, 36-70 years). Six of 37 evaluable patients achieved a partial response (16.2%; 95% confidence interval [CI], 4.4-28.0%). The durations of response were 1.1, 1.5, 1.7, 1.9, 3.4, and 4.6 months. The estimated median survival time was 7.4 months (95% CI, 5.1-9.7 months). Grade 3 or 4 toxicities were not observed. Grade 1 to 2 leukopenia, anemia, and thrombocytopenia were seen in 5 of 68 cycles, 16 of 68, and 2 of 68, respectively. Nonhematologic toxicities included grade 1 to 2 nausea or vomiting (30 of 68 cycles), nephrotoxicity (27 of 68), and hepatotoxicity (13 of 68). SKI 2053R showed a modest antitumor activity with limited toxicities in patients with ED SCLC. Further clinical trials are warranted in SCLC with a higher dose of SKI 2053R.

Simultaneous analysis of urinary 2-thiothiazolidine-4-carboxylic acid and thiocarbamide as a biological exposure index for carbon disulfide exposure.

The objectives of this study were to develop optimal analytic methods for detecting urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) and thiocarbamide simultaneously and to evaluate the usefulness of these metabolites to a biological exposure index (BEI) for carbon disulfide (CS2) exposure. For this experiment, synthesized TTCA and thiocarbamide were used. The synthesized TTCA was identified by infrared spectrophotometer, nuclear magnetic resonance spectrometer and thin layer chromatography. The recovery rates of both metabolites were calculated to find the optimum analytical method. The amounts of urinary TTCA and thiocarbamide were measured by using an ultraviolet detector connected to high performance liquid chromatography (HPLC) after the administration of CS2 (350, 700 mg/kg) into Sprague-Dawley rats intraperitoneally. The maximum absorbance wave lengths for TTCA and thiocarbamide were 272 and 236 nm, respectively. Ethyl acetate extraction with NaCl as a salting-out reagent was used as a simultaneous extraction method for these metabolites. HPLC conditions for these metabolites included using a NH2 column, 50 mM KH2PO4: acetonitrile (85:15) and pH 3. Excreted amounts of urinary TTCA and thiocarbamide were increased significantly following CS2 administration. TTCA, which was already adopted as a BEI for CS2 by the American Conference of Governmental Industrial Hygienists (ACGIH), seems to be a more useful BEI for CS2 exposure than thiocarbamide. However further studies are needed to increase analytical efficiency before thiocarbamide can be adopted as a BEI and to apply this analytic method for simultaneous analysis of these metabolites in workers exposed to CS2.

Short-term effects of iontophoresis on the structure of the guinea pig tympanic membrane.

Guinea pig tympanic membrane was anesthetized iontophoretically. The animals were sacrificed between 2 h and 4 days after the anesthesia and the tympanic membrane was studied histologically by light microscopy and transmission electron microscopy. Edema in the subepidermal connective tissue layer and detachment of the basement membrane from the basal cell layer were observed 2 h after iontophoresis. Eight and 12 h later, the epidermal layer between the handle of the malleus and the bony annulus peeled and retracted towards the bony annulus, leaving only hornified outer epidermis on the fibrous layer. Four days after iontophoresis, the retracted margin of the epidermal layer became greatly thickened and evidence of hyperplasia and migration was observed. This study has demonstrated that iontophoresis of the tympanic membrane produces remarkable histological changes. However, no perforation was observed.