Structure-toxicity analysis of type-2 alkenes: in vitro neurotoxicity.

Acrylamide (ACR) is a conjugated type-2 alkene that produces synaptic toxicity presumably by sulfhydryl adduction. The alpha,beta-unsaturated carbonyl of ACR is a soft electrophile and, therefore, adduction of nucleophilic thiol groups could occur through a conjugate (Michael) addition reaction. To address the mechanism of thiol adduct formation and corresponding neurotoxicological importance, we defined structure-toxicity relationships among a series of conjugated type-2 alkenes (1 microM-10mM), which included acrolein and methylvinyl ketone. Results show that exposure of rat striatal synaptosomes to these chemicals produced parallel, concentration-dependent neurotoxic effects that were correlated to loss of free sulfhydryl groups. Although differences in relative potency were evident, all conjugated analogs tested were equiefficacious with respect to maximal neurotoxicity achieved. In contrast, nonconjugated alkene or aldehyde congeners did not cause synaptosomal dysfunction or sulfhydryl loss. Acrolein and other alpha,beta-unsaturated carbonyls are bifunctional (electrophilic reactivity at the C-1 and C-3 positions) and could produce in vitro neurotoxicity by forming protein cross-links rather than thiol monoadducts. Immunoblot analysis detected slower migrating, presumably derivatized, synaptosomal proteins only at very high acrolein concentrations (>or= 25 mM). Exposure of synaptosomes to high concentrations of ACR (1M), N-ethylmaleimide (10mM), and methyl vinyl ketone (MVK) (100mM) did not alter the gel migration of synaptosomal proteins. Furthermore, hydralazine (1mM), which blocks the formation of protein cross-links, did not affect in vitro acrolein neurotoxicity. Thus, type-2-conjugated alkenes produced synaptosomal toxicity that was linked to a loss of thiol content. This is consistent with our hypothesis that the mechanism of ACR neurotoxicity involves formation of Michael adducts with protein sulfhydryl groups.     

Establishment and characterization of a human ovarian anaplastic carcinoma cell line

Ovarian carcinoma cell line HTBOA was established from a human ovarian anaplastic carcinoma. It has been proliferating stably since the beginning of culture 3 years ago after 91 passages. The cells were spindle like, oval, and polygonal in shape, and the nuclear chromatin was coarse in grain with many nucleoli, showing neoplasticity and pleomorphism. The cells proliferated rapidly, and the population doubling time was 24-28 hr. The chromosomes showed a wide distribution of aneuploidy, the mode was in the hypotriploid range, and many marker chromosomes were observed. Heterotransplantation was easy, and subcutaneous transplantation of 1 X 10(5) cells in nude mice forms a tumor that is histologically similar to the original anaplastic carcinoma. The most noteworthy characteristic of the cell line was that it caused granulocytosis in nude mice with carcinomas, and formed the colonies of granulocytes in an in vitro culture system. The cell line was considered to be producing a granulocyte colony-stimulating factor.     

Mitomycin-C-augmented trabeculectomy for neovascular glaucoma. A preliminary report

PURPOSE: This study aimed to investigate the safety and efficacy of trabeculectomy with intraoperative mitomycin C (MMC) in the management of eyes with neovascular glaucoma (NVG). METHODS: Fifteen eyes of 14 patients with NVG were included in the study. NVG was secondary to central retinal vein occlusion (3 eyes), hemiretinal vein occlusion (2 eyes), proliferative diabetic retinopathy (8 eyes), branch retinal vein occlusion (1 eye) and idiopathic (1 eye). Preoperative retinal ablation was performed in eyes with evidence of posterior segment ischaemia. Following this, all eyes underwent trabeculectomy with intraoperative MMC (0.4 mg/ml for 3 minutes). Clinical outcome assessment included visual acuity, intraocular pressure (IOP), bleb appearance, identification of complications and antiglaucoma medications required to control IOP. RESULTS: The mean IOP decreased from 38.6 +/- 12.9 mmHg (range, 15-64 mmHg) to 17.4 +/- 9.33 mmHg (range, 4-34 mmHg) (P = 0.001). Preoperative visual acuity ranged from light perception to 6/9 in the affected eye. Thirteen (86.6%) of 15 eyes improved vision or retained preoperative vision, one (6.7%) eye lost light perception and one (6.7%) eye developed tractional retinal detachment two years after trabeculectomy. Ten (66.7%) of 15 eyes were classified as surgical success with a mean follow-up of 28.6 +/- 26.3 months (range, 2-82 months). None of the patients developed choroidal haemorrhage, hypotony maculopathy, late onset bleb leak or endophthalmitis. CONCLUSION: Trabeculectomy with intraoperative MMC is a good treatment modality in the management of eyes with NVG.     

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.     

Dystypia: isolated typing impairment without aphasia, apraxia or visuospatial impairment

We report a 60-year-old right-handed Japanese man who showed an isolated persistent typing impairment without aphasia, agraphia, apraxia or any other neuropsychological deficit. We coined the term 'dystypia' for this peculiar neuropsychological manifestation. The symptom was caused by an infarction in the left frontal lobe involving the foot of the second frontal convolution and the frontal operculum. The patient's typing impairment was not attributable to a disturbance of the linguistic process, since he had no aphasia or agraphia. The impairment was not attributable to the impairment of the motor execution process either, since he had no apraxia. Thus, his typing impairment was deduced to be based on a disturbance of the intermediate process where the linguistic phonological information is converted into the corresponding performance. We hypothesized that there is a specific process for typing which branches from the motor programming process presented in neurolinguistic models. The foot of the left second frontal convolution and the operculum may play an important role in the manifestation of 'dystypia'.     

Functional maturation of periodontal mechanoreceptors during development in rats

The influence of development on periodontal mechanoreceptors (PMRs) was investigated in four groups of male Wistar albino rats aged 1, 3, 5 weeks and 6 months using an in vitro jaw-nerve preparation. The mean values of conduction velocities of the nerve innervating PMRs in 5-week and 6-month groups were significantly higher than those in the other two groups. All fiber types obtained in the 5-week and 6-month groups were Abeta. The mechanical thresholds of 5-week and 6-month groups were significantly higher than those of 1- and 3-week groups. These data suggest that the response properties of rat's PMRs are matured by 5-week after birth, when functional molar occlusion and transition of dietary contents from liquid to hard-diet can be achieved.     

Loss of hMSH2 and hMSH6 expression is frequent in sporadic endometrial carcinomas with microsatellite instability: a population-based study.

Microsatellite instability (MSI) seems to be important in the development of various human cancers including sporadic endometrial cancer. It has previously been shown that alterations in the mismatch repair gene hMLH1 seem to be important for the development of MSI in these tumors. The role of the other mismatch repair genes hMSH2 and hMSH6 has been less well studied, but investigations on patients with hereditary nonpolyposis colorectal cancer indicate that these genes also may be involved. We therefore wanted to investigate the pattern of hMSH2 and hMSH6 expression in a prospective and population-based series of endometrial carcinomas with known hMLH1 expression and MSI status. A total of 138 patients were studied, and pathological staining was seen in 19 cases (14%) for hMLH1, 26 cases (19%) for hMSH2, and 17 cases (12.3%) for hMSH6. Pathological hMLH1 expression was more frequent among tumors with high MSI (those positive for four to five of five markers), whereas pathological expression of hMSH2 and hMSH6 was more frequent among tumors with intermediate MSI (those positive for two to three of five markers). MSI was significantly correlated with pathological expression of hMLH1 (P < 0.001), hMSH2 (P = 0.04), and hMSH6 (P = 0.001). In the group with high MSI, 14 of 16 tumors (88%) showed pathological expression for at least one of the markers. The expression of hMLH1, hMSH2, or hMSH6 did not significantly influence survival. In conclusion, pathological expression of hMLH1 does not seem to account for all tumors with a MSI-positive phenotype in this population-based series of endometrial carcinomas. Our data indicate that the other mismatch repair genes hMSH2 and hMSH6 are also involved, especially in cases with intermediate MSI.