Automated lithology prediction from PGNAA and other geophysical logs.

Different methods of lithology predictions from geophysical data have been developed in the last 15 years. The geophysical logs used for predicting lithology are the conventional logs: sonic, neutron-neutron, gamma (total natural-gamma) and density (backscattered gamma-gamma). The prompt gamma neutron activation analysis (PGNAA) is another established geophysical logging technique for in situ element analysis of rocks in boreholes. The work described in this paper was carried out to investigate the application of PGNAA to the lithology interpretation. The data interpretation was conducted using the automatic interpretation program LogTrans based on statistical analysis. Limited test suggests that PGNAA logging data can be used to predict the lithology. A success rate of 73% for lithology prediction was achieved from PGNAA logging data only. It can also be used in conjunction with the conventional geophysical logs to enhance the lithology prediction.

Boron neutron capture therapy (BNCT) for malignant melanoma with special reference to absorbed doses to the normal skin and tumor.

Twenty-two patients with malignant melanoma were treated with boron neutron capture therapy (BNCT) using 10B-p-boronophenylalanine (BPA). The estimation of absorbed dose and optimization of treatment dose based on the pharmacokinetics of BPA in melanoma patients is described. The doses of gamma-rays were measured using small TLDs of Mg2SiO4 (Tb) and thermal neutron fluence was measured using gold foil and wire. The total absorbed dose to the tissue from BNCT was obtained by summing the primary and capture gamma-ray doses and the high LET radiation doses from 10B(n, alpha)7Li and 14N(n,p)14C reactions. The key point of the dose optimization is that the skin surrounding the tumour is always irradiated to 18 Gy-Eq, which is the maximum tolerable dose to the skin, regardless of the 10B-concentration in the tumor. The neutron fluence was optimized as follows. (1) The 10B concentration in the blood was measured 15-40 min after the start of neutron irradiation. (2) The 10B-concentration in the skin was estimated by multiplying the blood 10B value by a factor of 1.3. (3) The neutron fluence was calculated. Absorbed doses to the skin ranged from 15.7 to 37.1 Gy-Eq. Among the patients, 16 out of 22 patients exhibited tolerable skin damage. Although six patients showed skin damage that exceeded the tolerance level, three of them could be cured within a few months after BNCT and the remaining three developed severe skin damage requiring skin grafts. The absorbed doses to the tumor ranged from 15.7 to 68.5 Gy-Eq and the percentage of complete response was 73% (16/22). When BNCT is used in the treatment of malignant melanoma, based on the pharmacokinetics of BPA and radiobiological considerations, promising clinical results have been obtained, although many problems and issues remain to be solved.

Boron neutron capture therapy of malignant melanoma using 10B-paraboronophenylalanine with special reference to evaluation of radiation dose and damage to the normal skin.

A treatment regimen for boron neutron capture therapy of malignant melanomas is described using 10B-paraboronophenylalanine as the tumor-targeting compound. As a therapeutic dose, we adopted the maximum tolerable dose for the skin regardless of tumor 10B concentration. In practice, the maximum neutron fluence should be decided prior to starting irradiation. For this purpose, the kinetics of the concentration of 10B in the blood and skin and the skin-to-blood ratios were analyzed in the six patients who received 170 mg/kg of the compound intravenously, and skin concentrations during irradiation were predicted using a standard skin factor curve. This yields a skin concentration at time T based on the blood concentration at time 0. We calculated the maximum tolerable fluence yielding but not exceeding 18 RBE-Gy by assuming that the RBE of 14N(n,p)14C and 10B(n, alpha)7Li reaction for skin damage is 2.5. Actual skin reactions in three of five patients treated with the therapy were, as predicted, within tolerable limits, and we were able to obtain complete tumor regression in four cases. The results indicate that application of our logical approach will be useful for subsequent cases and further development of this therapy.

The relative biological effectiveness of 10B-neutron capture therapy for early skin reaction in the hamster.

The relative biological effectiveness (RBE) of 10B-neutron capture therapy (BNCT) on skin was analyzed using hamsters. The Kyoto University Research Reactor, which has a very low contamination of gamma rays and fast neutrons, was used as a thermal neutron source. Boron-10-para-boronophenylalanine hydrochloride ([10B]BPA.HCl) was administered to the hamsters. The evolution and time course of early skin reactions were assessed. These reactions were compared with those produced by electron beams. The maximum safe skin doses (no more than moist desquamation) of BNCT and electron beams were established to be 11 and 21 Gy, respectively. The RBE at this single dose with BNCT was found to be 1.94, assuming that the RBE of the gamma rays was 1.0 and each component of BNCT (mixed radiations) was simply additive.

[Postpolio late progressive muscular atrophy--clinical and epidemiologic analyses in 4 Japanese cases].

Four Japanese cases of postpolio progressive muscular atrophy (PPMA) of late onset were clinically studied to characterize their clinical features and discussed upon the epidemiologic viewpoint. Four male patients were included with mean age of 43.5 (30-59) years on examination, diagnosed as PPMA after the criteria by Alter (1982) and Dalakas (1986). All suffered from polio at age 10 month to 8 years (mean: 3y) between 1931 and 1957 with residual motor paresis in one limb or two. Twenty-eight to 55 (mean: 40.3) years later, subsequent muscle weakness and atrophy appeared in the limb seemingly unaffected by the initial polio attack. Marked fasciculations and occasional myalgias were noticed without sensory disturbance and bulbar as well as upper motor neuron signs. Laboratory examinations revealed moderate elevations of serum CK and protein content in SCF. No significant elevation of polio virus antibody titers was found in both serum and CSF. Electromyography showed neurogenic changes of various degrees by muscle tested. Muscle CT disclosed patchy distribution of atrophied muscles with fatty replacement in all extremities. Spinal cord MRI images were unremarkable. Scatters of small grouped atrophy and fiber type grouping were noticed on muscle biopsy specimens. These findings summarized in our cases are generally compatible with those of hereby reported PPMA cases. On reviewing the western literature and the great epidemic of polio around 1960 in Japan, an increasing number of patients with PPMA can be anticipated in near future; possibly in 10 years.

Estimation of absorbed dose in the covering skin of human melanoma treated by neutron capture therapy.

A patient with malignant melanoma was treated by thermal neutron capture therapy using 10B-paraboronophenylalanine. The compound was injected subcutaneously into ten locations in the tumor-surrounding skin, and the patient was then irradiated with thermal neutrons from the Musashi Reactor at reactor power of 100 KW and neutron flux of 1.2 X 10(9) n/cm2/s. Total absorbed dose to the skin was 11.7-12.5 Gy in the radiation field. The dose equivalents of these doses were estimated as 21.5 and 24.4 Sv, respectively. Early skin reaction after irradiation was checked from day 1 to day 60. The maximum and mean skin scores were 2.0 and 1.5, respectively, and the therapy was safely completed as far as skin reaction was concerned. Some factors influencing the absorbed dose and dose equivalent to the skin are discussed.

[Introduction of a method of promoting periodontal disease awareness].

In periodontal diseases, due to lack of subjective symptoms, disease awareness and professional consultations are often dismissed even by subjects with already established periodontal lesions. The purpose of this study was to gain data concerning the relationship between bleeding induced by interdental stimulating and some of the clinical indices used in routine periodontal examinations in order to consider if wooden interdental cleaners, which are available to patients themselves, could be used as a means of arousing disease awareness. Furthermore, the buccolingual insertion of interdental cleaners was confirmed together with reconsiderations on its role as a means of proximal plaque control. 180 interdental sites of 30 new out-patients suspected of gingivitis or periodontitis consisted the material. As comparative indices to interdental stimulating, Bleeding on Probing (BOP), Probing Depth (PD), Gingival Index (GI) and Gingival Crevicular Fluid (GCF) measurement were selected. The interdental cleaning efficiency was reconsidered by assessment of interproximal plaque removal. As a result, bleeding was induced both by interdental stimulating and probing in 106 of the 180 experimental sites and was the majority. In relation to PD, concerning pockets less than 1.5 mm, bleeding was not induced by interdental stimulating. 58.8% of 3 mm pockets and all of the pockets deeper than 5 mm bled on interdental stimulating. Concerning the relationship with the GI, no site evaluated GI. 0 bled on interdental stimulating. 12.9% of sites evaluates GI. 1, 73.3% of sites evaluated GI. 2, and all of the sites evaluated GI. 3 bled on interdental stimulating. 39.0% of sites with GCF measurement of 0-21, 51.9% of sites with GCF measurement of 21-40 and 96.8% of sites with GCF measurement of over 81 showed bleeding on interdental stimulating.(ABSTRACT TRUNCATED AT 250 WORDS)

[Xenon CT CBF mapping derived from two minutes inhalation].

Although xenon enhanced CT method for local cerebral blood flow measurement has been brought into a clinical practice, the technique has inherent limitations including anesthetic effects and expensive cost of xenon by a large consumption. To overcome these problems a modified method with a short-duration inhalation was developed and its validity was attested. Siemens Somatom SF with a resolution of 256 X 256 pixels and a scan time of 10 seconds was used. The subjects inhaled 50% Xe/O2 gas mixture from an apparatus consisted of Douglas bag and an open circuit. Xenon concentration in the expired gas was continuously monitored and estimated for arterial blood concentration by using a hematocrit correction. PaCO2 was monitored throughout the study. At the starting point and the endpoint of the inhalation two scans were performed respectively. Thus obtained four images were processed for CT noise cancellation, summation and subtraction to produce an in vivo autoradiography image. Local CBF was calculated from equations derived from the autoradiographic technique with a fixed partition coefficient of lambda = 1. Computer simulation studies were performed to find the optimal scan point to obtain an autoradiographic image and to estimate the calculation errors of this method. One minute and forty-five seconds was found to be the optimal scan point to gain an autoradiographic image in view of a balance between linearity of CBF/enhancement curve and total amount of tissue enhancement. The theoretical errors due to the assumption for a fixed partition coefficient were calculated to be 8% underestimation for gray matter and 5% overestimation for white matter.(ABSTRACT TRUNCATED AT 250 WORDS)

Regulation of galactocerebroside and sulfatide synthesis by hormones in chick neural cultures.

Chick neural cultures were used to study effects of insulin, thyrotropin releasing hormone, growth hormone and glucagon on myelin lipid synthesis in vitro. The incorporation of [3H]galactose into myelin associated lipids such as cerebroside and sulfatide was used as an index for various hormonal effects on myelination. The data suggest that these hormones were effective on myelin lipid synthesis only in the central nervous cells, not in the peripheral nerve cells.

[Clinical study on unmodified intravenous dried ion-exchange resin treated human normal immunoglobulin, SM-4300].

Unmodified intravenous dried ion-exchange resin treated human normal immunoglobulin, SM-4300, was administered to 4 patients with severely intractable infectious diseases. Obvious antipyretic effect, opsonic effect and and investigational findings on healing are not observed. However, in both subjective and objective clinical effects, we obtained the following test results, that is, 1 case of effective and 2 cases of rather effective. No side effects by SM-4300 were observed.