Airborne uranium contamination--as revealed through elemental and isotopic analysis of tree bark.

A new strategy for characterisation of airborne uranium contamination based on ICP mass spectrometric analysis of tree bark is described. The uranium content of tree barks (50 samples) obtained from diverse locations (remote, rural, industrial) varied over almost four orders of magnitude (0.001-8.3 micrograms/g U) with maximum concentrations recorded in the vicinity of a nuclear fuel fabrication plant (0.70-8.3 micrograms/g U). Elevated concentrations were also observed near a coal-fired power station (0.25-0.38 microgram/g U). Isotopic analysis revealed significant deviation from the natural uranium isotope ratio (235U/238U, 0.00725) at four nuclear installations (235U/238U, 0.0055-0.0097). These findings indicate that tree bark serves as an effective biomonitor for uranium and, with isotopic analysis, discrimination between nuclear and non-nuclear emissions is realised.

Effect of electrical stimulation of the thalamic Vim nucleus on hand tremor during stereotactic thalamotomy.

OBJECTIVE: The aim of this study was to analyze the correlation between neuronal responses in the thalamic ventralis intermedius (Vim) nucleus to peripheral, natural stimulation and the modulation of tremor by electrical stimulation during stereotactic thalamotomy. DESIGN AND METHODS: The authors studied 36 patients with hand tremor using a microelectrode. The responses of tremor to electrical stimulation were analysed electromyographically. Sixty stimulation sites were divided into three groups. RESULTS: Group A (20 sites) where responses to stretching of the contralateral forearm muscles were recorded. Group B (26 sites) where responses to stretching of the other muscles of the upper extremity were recorded. Electrical stimulation at sites in groups A and B temporarily suppressed the contralateral tremor, but the minimum current intensity to suppress tremor at sites in group A was less than that in group B. Electrical stimulation in group C (14 sites), where kinesthetic responses of contralateral lower extremity were recorded, resulted in increased amplitude of hand tremor. Selective coagulation including the area of tremor suppression resulted in abolition of the tremor in all patients. CONCLUSIONS: These results suggest that the most effective site for thalamotomy may also be suitable for chronic stimulation in the Vim nucleus.

[5-fluorouracil and low-dose leucovorin as surgical adjuvant therapy from viewpoint of long-term outcome].

Biochemical modulation of 5-FU by leucovorin (LV) has been demonstrated to increase the therapeutic effect compared to single agent 5-FU in the treatment of patients (pts) with advanced colorectal cancer. The purpose of this study was to determine the effectiveness of the 5-FU + LV combination as adjuvant therapy following surgery in pts with Dukes' B, C colon cancer. Pts were entered in a stratified clinical trial comparing two different combination chemotherapeutic regimens to single agent 5-FU, given orally as a control. This report summarized the result of treatment in 61 pts who were 5-FU oral alone and 32 pts who were 5-FU (375 mg/m2) and low-dose LV (20 mg/m2) intravenously for 5 days with 5-FU oral intake. 5-FU with LV regimen was associated with an improved survival compared with the single agent 5-FU oral intake (p < 0.05). 5-FU with LV regimen resulted in less recurrence in liver and lung compared with single-agent 5-FU oral intake.

Inhibitory effect of green tea extract on the process of pancreatic carcinogenesis induced by N-nitrosobis-(2-oxypropyl)amine (BOP) and on tumor promotion after transplantation of N-nitrosobis-(2-hydroxypropyl)amine (BHP)-induced pancreatic cancer in Syrian hamsters.

Epidemiologic studies have shown a lower risk of gastrointestinal cancer in green tea drinkers. In the present study, the inhibitory effect of green tea extract (GTE) on the process of pancreatic carcinogenesis induced by N-nitrosobis-(2-oxypropyl)amine (BOP) and on tumor promotion after transplantation of N-nitrosobis-(2-hydroxypropyl)amine (BHP)-induced pancreatic cancer were investigated in hamsters. In the first experiment, shortly after the initiation of pancreatic carcinogenesis by BOP, the animals in the GTE group were given GTE (0.5 mg/L) in their drinking water and the control group was given tap water. All animals were sacrificed 24 weeks later. There were no significant differences in body weight, water intake, or food consumption between the two groups during the experiments. GTE consumption was approximately 1.25 mg/day/100 g body weight during this experiment. Seven of the 13 hamsters (54%) in the control group were found to have pancreatic tumors, versus six of the 18 hamsters (33%) in the GTE group. The average number of tumors in the control group was 1.0/hamster, compared with 0.5/hamster in the GTE group. The overall incidence of macroscopic pancreatic tumors in the GTE group was about half that in the control group. The incidence of pancreatic cancer was 54% (12/13) in the control group and 44% (8/18) in the GTE group. The number of pancreatic cancers, including invasive carcinoma and carcinoma in situ, in the GTE group was 0.88/hamster, significantly lower than in the control group (1.68/hamster) (p < 0.05). The incidence of atypical ductal hyperplasia, which is thought to be an early pancreatic cancer, was also significantly lower in the GTE group than in the control group (1.50/hamster vs. 4.65/hamster) (p < 0.05). In the second experiment, 1-mm3 pieces of BHP-induced pancreatic cancer were transplanted into the back of hamsters. The control group (N = 16) was maintained on the basal diet and tap water throughout the experiment, and the GTE group (N = 16) was also maintained on the basal diet and tap water for the first 3 weeks after transplantation, when successful transplantation was confirmed and, thereafter, given tap water containing GTE (0.5 mg/L) for an additional 12 weeks. Tumor growth was similar in both groups until 11 weeks after transplantation, but inhibition of tumor growth became apparent after 11 weeks in the GTE group. At 13 weeks, the average tumor volume in the GTE group was 1.01 +/- 0.11 x 104 mm3, significantly smaller than that in the control group (1.98 +/- 0.37 x 104 mm3) (p < 0.05). The results demonstrated that GTE has an inhibitory effect on the process of pancreatic carcinogenesis and on tumor promotion of transplanted pancreatic cancer. These results suggest that GTE may come to serve as a chemopreventive and chemotherapeutic agent for pancreatic cancer.

The possible role of the cerebral cortex adjacent to the central sulcus for the genesis of central (thalamic) pain--a metabolic study.

In nine patients with central (thalamic) pain after stroke, X-CT, MRI, PET scan and intraoperative thalamic microrecordings were performed. The PET studies made use of Sokoloff's method with 18FDG and a steady-state method with C15O2-15O2. CT scan and MRI revealed definite thalamic damage (Th) in 3 cases, putaminal damage (Put) in 3 cases, combined damage (Th + Put) in one case, and cortical (parietal) damage in 2 cases. In patients with a subcortical lesion, the greater the severity of superficial pain, the higher was the relative value of regional cerebral glucose metabolism (rCMRGlu) as compared to oxygen metabolism (rCMRO2) in the cerebral cortex around the central sulcus on the damaged side. Also, in a case with combined (Th + Put) lesion, regional oxygen extraction ratio (rOEF) was increased in this area. Moreover, in another case, central pain disappeared after a small subcortical haemorrhage in the same structure. In all patients including those with a cortical lesion, rCMRGlu was decreased in the postero-lateral (sensory) thalamus on the invalued side. The possible role of the cerebral cortex around the central sulcus for the genesis of central pain is discussed.

[The effect of hyperthermia against pancreatic cancer cell--various examinations including flow cytometric bromodeoxyuridine/DNA analysis].

We investigated the effect of hyperthermia against pancreatic cancer cell in various aspects including of cytokinetics. The hyperthermia above 43 degrees C was thought to have strong effect for the studies on surviving cell number and morphological change of Capan-2 and RWP-1 cells after heating treatment. The cell inoculated to the nude mice subcutaneously after heating treatment at 43 degrees C was recognized the tumor forming at 3 weeks later, however, the growth speed was slower than that of control to which untreated Capan-2 cells were inoculated. As the case of 44 degrees C, the tumor forming was not recognized at all. The cytokinetics was measured by flow cytometric bromodeoxyuridine (BrdUrd)/DNA analysis. Up to 43 degrees C in accordance with increase in the heating temperature, the accumulation in G2M phase increased, and the amount of BrdUrd incorporated 5 phase decreased. At the temperature above 44 degrees C, BrdUrd was hardly incorporated into S phase cells and the cell cycle was almost stopped. These results suggested the usefulness of hyperthermia and strong effect of heating treatment above 44 degrees C against pancreatic cancer cell.

Flow cytometric bromodeoxyuridine/DNA analysis of hyperthermia and/or adriamycin for human pancreatic adenocarcinoma cell line Capan-2.

The effects of hyperthermia, adriamycin (ADM), and hyperthermia combined with ADM on pancreatic cancer cells were investigated from the viewpoint of cytokinetics using flow cytometric bromodeoxyuridine (BrdUrd)/DNA analysis. Human pancreatic adenocarcinoma cell line Capan-2 was used. The untreated cells could be clearly divided into G1, S, G2M phases on contour plots of BrdUrd/DNA distribution. After heat treatment at 41-43 degrees C, there was an accumulation of cells in the G2M phase which was correlated with the increase in temperature. After heat treatment at 44 or 45 degrees C, there was marked increase in non BrdUrd-labeled cells in the S phase. ADM caused no change in the percent of non BrdUrd-labeled cells in the S phase, even after treatment with a concentration of 1.0 micrograms/ml, though that concentration of ADM caused a marked increase in the percent of cells in the G2M phase. After hyperthermia combined with ADM, the accumulation of the G2M phase increased remarkably, and was significantly higher than that after each treatment alone (P less than 0.005); however, non BrdUrd-labeled cells in the S phase did not increase. In this study the synergistic effect of hyperthermia combined with ADM in increasing the percent of cells in the G2M phase could be observed by flow cytometry. The study illustrates the importance of performing in vitro flow cytometric BrdUrd/DNA analysis of combined therapy prior to the use of the combined therapy in patients.

[A case of midbrain and thalamic infarction showing Collier's sign in one side and blepharoptosis in the other side].

A 68-year-old man was admitted to the hospital complaining of aphasia and right hemiparesis. Neurological examination revealed aphasia, right hemiparesis and ataxia in the left upper extremity. He showed striking ocular symptoms: intense retraction of the right eyelid (Collier's sign), complete ptosis of the left eyelid which might conceal Collier's sign, marked upward gaze palsy and slight downward gaze palsy. Vertebral angiography and MRI revealed an infarction in the left medial area and the left crus cerebri in the upper midbrain, the left subthalamic area inferomedially extending from the adjacent area to the posterior commissure and the medial area in the left thalamus resulting from occlusion of the left mesencephalic artery. From these MRI findings and the reports on pathological findings of patients with Collier's sign, we suggest that damage in the posterior commissure or its adjacent area may be responsible for the sign. Upward gaze palsy is often associated with Collier's sign because fibers mediating upward gaze may decussate in the posterior commissure. Third nerve palsy is also associated with the Collier's sign in some patients. The mechanism creating Collier's sign may be a disturbance of inhibitory fibers leading to the motoneuron pool of the levator muscle in the posterior commissure or its adjacent area.

Pancreatography with contrast medium containing polyethylene hydrogenated castor oil.

A new contrast medium has been used for endoscopic pancreatography. Good visualization of the pancreas was obtained by this method. No side-effects of this method were observed by clinical and histologic examination, either in clinical or experimental studies. Clinically, the new method provided more detailed information regarding pancreatic changes in chronic pancreatitis. It is suggested that this method may make detection of a small tumor of the pancreas in the parenchyma and permit earlier diagnosis of carcinoma of the pancreas.