Ganglioside GD1a inhibits HGF-induced motility and scattering of cancer cells through suppression of tyrosine phosphorylation of c-Met.

We previously reported that ganglioside GD1a, which is highly expressed in poorly metastatic FBJ-S1 cells, inhibits the serum-induced motility of FBJ-LL cells and that the metastatic potential of FBJ-LL cells is completely suppressed by enforced GD1a expression (Hyuga et al., Int J Cancer 1999;83:685-91). We recently discovered that hepatocyte growth factor (HGF) induces FBJ-LL cell motility. In the present study, the HGF-induced motility of FBJ-S1 cells was found to be one-thirtieth that of FBJ-LL cells. This motility of GD1a-expressing transfectants, which were produced by transfection of FBJ-LL cells with GM2/GD2 synthase cDNA, decreased with increases in their GD1a expression and HGF induced almost no motility in GD1a-pretreated FBJ-LL cells, indicating that GD1a inhibits the HGF-induced motility of FBJ-LL cells. The expression of the HGF receptor c-Met on FBJ-S1 cells, FBJ-LL cells, transfectants and a mock-transfectant was almost the same. The level of tyrosine phosphorylation of c-Met after HGF stimulation in FBJ-S1 cells, GD1a-pretreated FBJ-LL cells and a GD1a-expressing transfectant was significantly lower than in FBJ-LL cells and a mock-transfectant. These findings suggested that GD1a inhibits the HGF-induced motility of FBJ-LL cells through suppression of tyrosine phosphorylation of c-Met. HepG2 cells, a human hepatoma cell line, were used to investigate whether GD1a interferes with other cancer cells expressing c-Met. HepG2 cells did not express GD1a. HGF induced cell scattering of HepG2 cells and the scattering was inhibited by pretreating the cells with GD1a. The c-Met in the cells was autophosphorylated by stimulation with HGF, but after treating the cells with GD1a, the HGF-induced autophosphorylation of c-Met was suppressed. These results suggest that GD1a acts as a negative regulator of c-Met in cancer cells.

Occurrence of transsulfuration in synthesis of L-homocysteine in an extremely thermophilic bacterium, Thermus thermophilus HB8.

A cell extract of an extremely thermophilic bacterium, Thermus thermophilus HB8, cultured in a synthetic medium catalyzed cystathionine gamma-synthesis with O-acetyl-L-homoserine and L-cysteine as substrates but not beta-synthesis with DL-homocysteine and L-serine (or O-acetyl-L-serine). The amounts of synthesized enzymes metabolizing sulfur-containing amino acids were estimated by determining their catalytic activities in cell extracts. The syntheses of cystathionine beta-lyase (EC 4.4.1.8) and O-acetyl-L-serine sulfhydrylase (EC 4.2.99.8) were markedly repressed by L-methionine supplemented to the medium. L-Cysteine and glutathione, both at 0.5 mM, added to the medium as the sole sulfur source repressed the synthesis of O-acetylserine sulfhydrylase by 55 and 73%, respectively, confirming that this enzyme functions as a cysteine synthase. Methionine employed at 1 to 5 mM in the same way derepressed the synthesis of O-acetylserine sulfhydrylase 2.1- to 2.5-fold. A method for assaying a low concentration of sulfide (0.01 to 0.05 mM) liberated from homocysteine by determining cysteine synthesized with it in the presence of excess amounts of O-acetylserine and a purified preparation of the sulfhydrylase was established. The extract of cells catalyzed the homocysteine gamma-lyase reaction, with a specific activity of 5 to 7 nmol/min/mg of protein, but not the methionine gamma-lyase reaction. These results suggested that cysteine was also synthesized under the conditions employed by the catalysis of O-acetylserine sulfhydrylase using sulfur of homocysteine derived from methionine. Methionine inhibited O-acetylserine sulfhydrylase markedly. The effects of sulfur sources added to the medium on the synthesis of O-acetylhomoserine sulfhydrylase and the inhibition of the enzyme activity by methionine were mostly understood by assuming that the organism has two proteins having O-acetylhomoserine sulfhydrylase activity, one of which is cystathionine gamma-synthase. Although it has been reported that homocysteine is directly synthesized in T. thermophilus HB27 by the catalysis of O-acetylhomoserine sulfhydrylase on the basis of genetic studies (T. Kosuge, D. Gao, and T. Hoshino, J. Biosci. Bioeng. 90:271-279, 2000), the results obtained in this study for the behaviors of related enzymes indicate that sulfur is first incorporated into cysteine and then transferred to homocysteine via cystathionine in T. thermophilus HB8.

Event-related brain potentials in response to novel sounds in dementia.

OBJECTIVE: Non-target, deviant stimuli generate an earlier latency, front-central novelty P3, whereas correctly detected task-relevant stimuli generate a parietal maximal target P3. We examined whether the P3 component to novel stimuli is affected by dementing processes, and is therefore useful for distinguishing Alzheimer's type dementia (AD) from vascular dementia (VD). METHODS: We recorded ERPs to task-relevant stimuli (target P3) and novel task-irrelevant stimuli (novelty P3) in an auditory oddball task in AD (n = 16), VD (n = 16), and age-matched controls (n = 18). The amplitude, latency, and scalp topography of target and novelty P3 were compared among 3 groups using ANOVA. The relationship between P3 measures and intelligence scores were evaluated by correlation analysis. RESULTS: The amplitude, latency and scalp topography of the target P3 were comparably affected by both AD and VD. However, the amplitude of the novelty P3 was markedly reduced in VD, but not in AD, and the scalp topographics were different in the 3 groups. The amplitude was maximal at frontal sites in controls, at central sites in AD, and at parietal sites in VD. The target P3 latency was prolonged in both AD and VD, whereas the novelty P3 latency was only prolonged in VD. AD was discriminated satisfactorily from VD by using the novelty amplitude at Cz and the ratio of the amplitudes at Fz and Pz as independent variables. CONCLUSIONS: These results suggest that the response to novel stimuli is differentially affected by dementia with degenerative and vascular etiology.

[Long-term administration of carmofur as a post-operative adjuvant chemotherapy for cervical adenocarcinoma. Cervical Adenocarcinoma Cooperative Research Association].

Cervical adenocarcinoma and adenosquamous cell carcinoma are low in radiation sensitivity, and the prognosis is said to be inferior to that of squamous cell carcinoma. Eleven facilities nationwide participated in the historical control study on the recurrence prevention effect of carmofur (HCFU) administered at 300 mg/day for more than two years postoperatively as an adjuvant chemotherapy to patients with cervical adenocarcinoma or adenosquamous cell carcinoma for which radical operation is possible. Registered for the study was a total of 252 patients: 77 patients for whom administration of carmofur was begun during the period from January 1987 and March 1989, 71 patients (control 1) who were treated for the cancer after January 1982 but did not receive adjuvant chemotherapy, and 104 patients who received adjuvant chemotherapies with other than carmofur (control 2). In analyses with the Kaplan-Meier method, the carmofur administration group demonstrated a better cumulative survival rate and disease free rate than control 1 (no adjuvant chemotherapy), suggesting carmofur was effective in preventing the recurrence of cervical adenocarcinoma and adenosquamous cell carcinoma.

A case of treatment-related leukoencephalopathy: sequential MRI, CT and PET findings.

A case of treatment-related leukoencephalopathy is presented. A patient with medulloblastoma was postoperatively treated with craniospinal axis irradiation. One month after irradiation, weekly intrathecal administration of methotrexate was performed 4 times to treat cerebrospinal fluid dissemination of the tumor. Two months after the initiation of intrathecal chemotherapy, the patient became somnolent and developed decerebrate posturing. Magnetic resonance imaging showed diffuse leukoencephalopathy. Positron emission tomography revealed a diffuse decrease in glucose uptake in the deep white matter. Auditory evoked potential also showed diffuse abnormalities, not only in the cerebrum, but also in the brain stem. High dose intravenous leucovorin rescue was attempted without any neurologic improvement.

[Chemotherapy of cancer of the cervix].

Systemic chemotherapy has been widely used for the purpose of inducing remission of advanced cancer of the cervix. Almost all anti-cancer drugs have been applied to this way of chemotherapy, however, the high effectiveness of cisplatin is worthy of notice, and this drug plays a central role in combination chemotherapy. Local hyperthermia, drug-induced hypertension and intra-arterial infusion of anti-cancer drugs are the representative methods to reinforce the effect of chemotherapy. Adjuvant chemotherapy has to be designed to adapt the extremely slow growing potential of residual microcarcinomas after surgery. Oral administration of tegafur for two years is a choice of maintenance chemotherapy preventive against postoperative recurrence.

[Intraoperative liquid embolization of an arteriovenous malformation in the basal ganglia and thalamic region].

Total three patients with arteriovenous malformation (AVM) in basal ganglia or thalamic region were treated by intraoperative liquid embolizations. These procedures were decided because of repeated hemorrhagic episodes. In the case with AVM in the head of the caudate nucleus which was fed by several anterior perforating arteries originated from anterior cerebral artery (A1 portion) and middle cerebral artery (M1 portion), frontotemporal craniotomy was performed. After the microsurgical dissection of these feeders, one of the feeders lenticulostriate artery, was cannulated with a small-caliber polyethylene catheter, 0.6 mm in outer diameter and 0.3 mm in inner diameter. A small amount of isobutyl 2-cyanoacrylate (IBCA) was injected through the catheter. Same procedure was carried out one month later. Postoperative angiograms revealed about 90% loss of AVM. In two cases with AVM which involved almost entire thalamus, subtemporal craniotomy was done. Feeding vessels which originated from posterior communicating artery and posterior cerebral artery (PCA) were carefully dissected under the operative microscope and one of them was prepared for cannulation with small catheter. When the small amount of IBCA was injected, proximal PCA and internal carotid artery were temporarily occluded. In both cases intraoperative embolization was carried out twice. Postoperative angiograms revealed that the size of AVM was decreased to 20% in one and 40% in the other. Although temporary postoperative deterioration of neurological deficits such as hemiparesis and visual disturbance was slightly noted in all cases, no hemorrhagic episode was experienced for 6 months, 1.5 and 2 years in each after embolization.

Experimental study on the effect of large-dose intratumoral OK-432 administration in mice.

This experimental study was undertaken to evaluate the effectiveness of a large-dose intratumoral administration of OK-432, which has already been found to be effective when combined with Mitomycin-C, 5-fluorouracil, and cytosine arabinoside, and/or small-dose of OK-432 in clinical use. Large-dose of OK-432 was administered intratumorally 15 days after the subcutaneous inoculation of 2.5 X 10(6) Ehrlich carcinoma cells. At the same time, 2.5 X 10(6) tumor cells were re-challenged intraperitoneally. A combined treatment with a small-dose of OK-432 and Mitomycin-C, cyclophosphamide, or 5-fluorouracil was also made. As a large-dose of OK-432, three-dose regimen of 1,000, 500, and 100 KE/kg was tested. As a small-dose of OK-432, 4 consecutive daily intramuscular injection of 50 KE/kg was examined. From the results obtained the initial intratumoral administration of a large-dose of OK=432 was found to be beneficial for the following combined treatment with a small-dose of OK-432 and Mitomycin-C or cyclophosphamide. The change of phytohemagglutinin (PHA) responsiveness of spleen cells after intratumoral injection of a large-dose of OK-432 was investigated in mice. These results indicated a decrease of PHA responsiveness of spleen cells according to the tumor growth. The intratumoral large-dose administration of OK-432 suggested inhibition of the decrease in PHA responsiveness. The most effective and suitable dose in this experiment was found to be 500 KE/kg in the three-dose regimen.

Fasting therapy for psychosomatic diseases with special reference to its indication and therapeutic mechanism.

It has been well known that the fasting therapy which was invented in Medical School of Tohoku University reveals an excellent effect upon various kinds of psychosomatic diseases, but its therapeutic mechanism and suitable indication are not yet explained completely. In order to corroborate these problems, this study was undertaken on 262 cases of psychosomatic diseases in the field of internal medicine. It is a complete fasting for 10 days with nothing by mouth except for drinking water, and 500 ml of parenteral fluid containing vitamins are administered intravenously every day. Absolute bed rest and self meditation are required in a closed individual room, and patients are not allowed to meet anyone but physicians and nurse in charge. The return to normal ordinary diet follows the order of fluid diet, soft diet and semiordinary diet during 5 days. In the period of the therapy, various clinical and laboratory examinations were carried out. Significance of these examinations consists in prediction of possible danger during the fasting period and elucidation of its therapeutic mechanism. Consequently, an outstanding efficacy rate of 87% with excellent prognosis was attained, and the following diseases were determined as suitable indication of this therapy; irritable colon, dysorexia nervosa, borderline hypertension, neurocirculatory asthenia, bronchial asthma, mild diabetes mellitus, obesity, lumbago without organic findings, conversion hysteria, various neurosis with somatic symptoms and masked depression. Possible mechanism of action of the therapy is that fasting acts as an extreme stress on the function of the autonomic nervous and endocrine systems, then it regulates the function of whole body including the brain, also it acts as one of the behaviour therapy for abnormal conditioning.

Statistical analysis of diverticulosis of the colon.

Forty-four cases of diverticulosis of the colon were detected among 2,662 cases examined by barium enema in Tohoku University. This corresponds to 1.7% in frequency. On the other hand, 21 cases were found among 1,511 cases examined in Hirosaki University, giving 1.4% in frequency. It was more frequent in the male. The frequency, as calculated on the basis of the numbers of cases examined by barium enema in separate age groups, showed the gradual increase with age except for above the eighth decade. The location where the diverticulum was most frequently seen was the right colon; namely, cases in which the diverticulum occurred from the cecum to the ascending colon and those in which it was found only in the ascending colon occupied 61.4 and 71.4% of the total cases, respectively. Diverticulitis as a complication was rare, while coincidence of polyp or carcinoma was sometimes observed. Furthermore, the value of fiberscopy for the diagnosis of diverticulosis of the colon was discussed, and its usefulness for the detection of complication was emphasized.