Catechol and hydroquinone have different redox properties responsible for their differential DNA-damaging ability.

We examined the redox properties of the "carcinogenic" catechol and the "noncarcinogenic" hydroquinone in relation to different DNA damaging activities and carcinogenicity using 32P-labeled DNA fragments obtained from the human genes. In the presence of endogenous NADH and Cu2+, catechol induces stronger DNA damage than hydroquinone, although the magnitudes of their DNA damaging activities were reversed in the absence of NADH. In both cases, DNA damage resulted from base modification at guanine and thymine residues in addition to strand breakage induced by Cu+ and H2O2, generated during the oxidation of catechol and hydroquinone into 1,2-benzoquinone and 1,4-benzoquinone, respectively. EPR and 1H NMR studies indicated that 1,2-benzoquinone is converted directly into catechol through a nonenzymatic two-electron reduction by NADH whereas 1,4-benzoquinone is reduced into hydroquinone through a semiquinone radical intermediate through two cycles of one-electron reduction. The reduction of 1,2-benzoquinone by NADH proceeds more rapidly than that of 1,4-benzoquinone. This study demonstrates that the rapid 1,2-benzoquinone two-electron reduction accelerates the redox reaction turnover between catechol and 1,2-benzoquinone, resulting in the enhancement of DNA damage. These results suggest that the differences in NADH-mediated redox properties of catechol and hydroquinone contribute to their different carcinogenicities.     

Treatment of recurrent malignant supratentorial astrocytomas with carboplatin and etoposide combined with recombinant mutant human tumor necrosis factor-alpha

BACKGROUND: This study assesses the safety, tolerance and preliminary efficacy of combined treatment with carboplatin, etoposide and recombinant human mutant tumor necrosis factor-alpha (TNF-SAM2) for recurrent malignant supratentorial astrocytomas at first relapse. MATERIALS AND METHODS: Carboplatin was administered intravenously at a dose of 400 mg/m2 on Day 1, while etoposide was administered intravenously at a dose of 100 mg/m2 from Day 1 to Day 3 for 3 days. From Day 7, 80x10(4) U/m2 TNF-SAM2 was given intravenously for up to 5 injections for 2 weeks. Treatment was repeated every 8 to 12 weeks. RESULTS: Ten patients previously treated with surgery, radiation therapy and chemotherapy with a nitrosourea (ranimustine: MCNU) for malignant astrocytomas received this regimen for up to four cycles. Three patients with anaplastic astrocytomas, one patient with anaplastic oligoastrocytoma and 6 patients with glioblastomas (3 men and 7 women), aged 27 to 69 years, were eligible and were evaluated for response and toxicity. Grade 2 and 3 hematological toxicities occurred in 4 (40%) and 2 patients (20%), respectively. Grade 2 hepatic toxicity was observed in two patients. Of 9 evaluable patients, three (33%), including one glioblastoma, partially responded to the treatment (PR) with time to tumor progression (TTP) of 231, 121 and 57 weeks, respectively. Two patients had stable disease (SD), while 4 glioblastomas (44%) had progressive disease (PD) with TTP values of 11, 15, 6 and 12 weeks, respectively. CONCLUSION: These results suggest that combined therapy with carboplatin, etoposide and recombinant mutant TNF-alpha in this patient population seems to be safe and acceptable and may benefit those with recurrent anaplastic astrocytomas. These intriguing clinical observations warrant a properly stratified randomized trial to determine whether this approach can provide therapeutic benefits and improve survival.     

Electron microscopic abnormalities of skeletal muscle in patients with collagen VI deficiency in Ullrich's disease

By electron microscopy, we examined the skeletal muscle from two patients with Ullrich's disease. One patient had a deletion in the collagen VI alpha 2 gene. The muscle biopsy specimens showed no collagen VI immunoreaction, while the expression of collagen IV was increased. Collagen VI is a microfibrillar protein in the extracellular matrix with cell adhesive properties, and collagen IV is a principal component of the basal lamina. Electron microscopy revealed unevenness, extension, and folding of the muscle plasma membrane, and showed thickening and overproduction of the basal lamina. The data show that type VI collagen is certainly one of the important extracellular matrix components maintaining the structural integrity of skeletal muscle, and a defect of the collagen VI protein causes abnormalities of the muscle plasma membrane, dystrophic muscle changes, and up-regulation of collagen IV.     

A case of central retinal artery occlusion after anterior posterior fusion of the lumbar spine

We report a case of central retinal artery occlusion after anterior-posterior fusion of the lumbar spine. The patient suddenly lost his vision of the right eye in the ICU just after the end of long procedure for anterior-posterior fusion of the lumbar spine. The patient was diagnosed as having central retinal artery occlusion, and treated successfully with treatments including immediate administration of urokinase and PGE1, stellate ganglion block, and hyperbaric oxygen therapy. The patient was discharged from the hospital on the 54th postoperative day with adequate vision to drive a car. Central retinal artery occlusion is a rare but very serious complication during and after supine surgery with prone position. It is very important for us to be aware of its possible occurrence. We have to diagnose and treat, as soon as possible, the vision loss after the spine surgery.     

The effects of epidural block on the distribution of lymphocyte subsets and natural-killer cell activity in patients with and without pain

Although epidural anesthesia prevents immune suppression during surgery, no reports have elucidated how epidural block affects immune response in nonsurgical patients. We examined changes in proportion of lymphocyte subsets and in natural-killer (NK) cell activity in patients with and without pain. Fifteen patients with pain (Pain group) and 15 preoperative patients without pain (Preoperative group) received three different treatments in random order: epidural block with 7 mL 1% lidocaine, epidural injection of an identical volume of normal saline, and IV injection of 1 mg/kg lidocaine. Blood samples were drawn before and after 30, 60, and 120 min of treatment. During epidural block at 30 and 60 min, both groups showed significantly decreased epinephrine, norepinephrine, and cortisol levels, and the proportion of NK cells decreased, whereas the CD4+/CD8+ ratio increased significantly. NK cell activity in both groups decreased significantly at 30 and 60 min. At 120 min, the variables had all returned to preblock values. During treatments with saline and IV lidocaine, neither group showed significant changes in any of the above variables. We conclude that epidural block causes a transient and significant alteration of lymphocyte subsets and NK cell activity regardless of pain status.     

Anti-herpes virus activity of fabaceous triterpenoidal saponins')

Anti-herpes simplex virus type 1 (HSV-1) activity of oleanane-type triterpenoidal saponins obtained from some fabaceous plants were examined. Among sophoradiol glycosides, the order of potency was kaikasaponins III>I>sophoradiol monoglucuronide. It was suggested that the trisaccharide group showed greater action than the disaccharide group. Neither the monoglucuronide of sophoradiol nor that of soyasapogenol B showed activity. Among the trisaccharide group of soyasapogenol B, the order of activity was azukisaponin V>soyasaponin II>astragaloside VIII>soyasaponin I. Therefore, the saponin having a glucosyl unit in the central sugar moiety seemed to show greater action. In comparison with the activities for a group having the same trisaccharide, the potency of the sapogenol moieties was found to be in the order of soyasapogenol E>sophoradiol>soyasapogenol B. Hence, the carbonyl group at C-22 would be more effective than the hydroxyl group in anti-HSV-1 activity, while the hydroxyl group at C-24 could reduce the activity.     

Expandable metallic stent for the treatment of left-sided colonic obstruction with malignant disease

Recently, it was reported that an EMS (expandable metallic stent) was useful for treatment of colorectal obstruction. In our department, EMSs were used for seven patients with left-sided colonic obstruction with unresectable malignant disease. After these treatments with EMS, their symptoms were improved and they were able to intake food. Stomal formation was avoided except in one patient with severe soiling. In conclusion, EMS is thought to be useful for the improvement of quality of life in the patients with unresectable malignant colonic obstruction.