Study on transport of negative ion plasma using dc laser photodetachment method

Transport of negative ion containing plasma was studied in a hydrogen plasma by injecting a semiconductor laser to make an electron density perturbation by photodetachment of negative ions. Change due to laser irradiation on electron saturation current to a Langmuir probe and that on electron current extracted through an orifice biased at the anode potential were measured phase sensitively by a lock-in-amplifier. The measured transport velocity of the negative ion containing plasma was about 1.4x10(5) cm/s for both cases. The photodetachment signal measured through the orifice had given a larger ratio of negative ion density to electron density. Change in transport of negative ion containing plasma around the Langmuir probe has been also investigated by detecting photodetachment signal onto electron current extracted through an orifice.

[Extrapleural pneumonectomy of malignant pleural mesothelioma]

We analyzed 7 patients with malignant pleural mesothelioma who underwent extrapleural pneumonectomy. Six men and a woman had a mean age of 65 years old. The postoperative mortality rate was 14% (1 death) and morbidity, 43% (3 cases). According to staging of International Mesothelioma Interest Group, 2 patients had stage I disease, 1 did stage II, 3 did stage III and 1 did stage IV. Local recurrences were found in 3 patients and metastasis in 2. In patients with local recurrences, 2 had irradiation with chemotherapy and 1, irradiation. In patients with recurrences of metastasis, 1 had chemotherapy and 1, supportive care. Seven patients with extrapleural pneumonectomy and 10 without surgery had median survivals of 16 months and 10 months, 1-year survival rates of 71% and 40% and 2-year survival rates of 57% and 0% respectively (p=0.071). Extrapleural pneumonectomy with adjuvant therapy could be effective treatment for malignant pleural mesothelioma.

Phase III trial of high- vs. low-dose-rate interstitial radiotherapy for early mobile tongue cancer

PURPOSE

Early mobile tongue cancer can be controlled with interstitial radiotherapy (ISRT). We carried out a Phase III trial to compare the treatment results of low-dose-rate (LDR) ISRT and high-dose-rate (HDR) ISRT for early mobile tongue cancer.

METHODS AND MATERIALS

From April 1992 through October 1996, 59 patients with cancer of the early mobile tongue were registered in this Phase III study. Eight patients were excluded from the evaluation because of violations of the requirements for this study. Of 51 eligible patients, 26 patients were treated with LDR-ISRT (70 Gy/4-9 days) and 25 patients with HDR-ISRT (60 Gy/10 fractions/1 week). For the hyperfractionated HDR-ISRT, the time interval between 2 fractions was more than 6 h.

RESULTS

Five-year local control rates of the LDR and HDR groups were 84% and 87% respectively. Nodal metastasis occurred in 6 patients in each group. Five-year nodal control rates of the LDR and HDR groups were 77% and 76%, respectively.

CONCLUSION

Hyperfractionated HDR-ISRT for early mobile tongue cancer has the same local control compared with continuous LDR-ISRT. Hyperfractionated HDR-ISRT is an alternative treatment for continuous LDR-ISRT.

[Clinical experience of new stereotactic radiotherapy system named CyberKnife]

The CyberKnife is a small linear accelerator mounted on a robot. The CyberKinfe has the IPS(Image Processing System) that evaluates the patient position during the treatment. If there is any movement of the patient, the robot chases the tumor. Invasive flame to fix the patient skull is not needed. From April 1998 through July 2000, we applied the CyberKnife treatment for 136 sites in 94 patients. Sixty-seven of 136 sites were metastatic brain tumors. Progression-free rate of tumors treated with 24-27 Gy at 3 months after treatment was 89%. There was no severe adverse effects except epilation. The CyberKnife treatment was applied for tumors in the body in USA. It will be available in Japan in near future.

Partial characterization of an enzyme fraction with protease activity which converts the spore peptidoglycan hydrolase (SleC) precursor to an active enzyme during germination of Clostridium perfringens S40 spores and analysis of a gene cluster involved in the activity

A spore cortex-lytic enzyme of Clostridium perfringens S40 which is encoded by sleC is synthesized at an early stage of sporulation as a precursor consisting of four domains. After cleavage of an N-terminal presequence and a C-terminal prosequence during spore maturation, inactive proenzyme is converted to active enzyme by processing of an N-terminal prosequence with germination-specific protease (GSP) during germination. The present study was undertaken to characterize GSP. In the presence of 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS), a nondenaturing detergent which was needed for the stabilization of GSP, GSP activity was extracted from germinated spores. The enzyme fraction, which was purified to 668-fold by column chromatography, contained three protein components with molecular masses of 60, 57, and 52 kDa. The protease showed optimum activity at pH 5.8 to 8.5 in the presence of 0.1% CHAPS and retained activity after heat treatment at 55 degrees C for 40 min. GSP specifically cleaved the peptide bond between Val-149 and Val-150 of SleC to generate mature enzyme. Inactivation of GSP by phenylmethylsulfonyl fluoride and HgCl(2) indicated that the protease is a cysteine-dependent serine protease. Several pieces of evidence demonstrated that three protein components of the enzyme fraction are processed forms of products of cspA, cspB, and cspC, which are positioned in a tandem array just upstream of the 5' end of sleC. The amino acid sequences deduced from the nucleotide sequences of the csp genes showed significant similarity and showed a high degree of homology with those of the catalytic domain and the oxyanion binding region of subtilisin-like serine proteases. Immunochemical studies suggested that active GSP likely is localized with major cortex-lytic enzymes on the exterior of the cortex layer in the dormant spore, a location relevant to the pursuit of a cascade of cortex hydrolytic reactions.

Cleavage of a C-terminal peptide is essential for heptamerization of Clostridium perfringens epsilon-toxin in the synaptosomal membrane

Activation of Clostridium perfringens epsilon-protoxin by tryptic digestion is accompanied by removal of the 13 N-terminal and 22 C-terminal amino acid residues. In this study, we examined the toxicity of four constructs: an epsilon-protoxin derivative (PD), in which a factor Xa cleavage site was generated at the C-terminal trypsin-sensitive site; PD without the 13 N-terminal residues (DeltaN-PD); PD without the 23 C-terminal residues (DeltaC-PD); and PD without either the N- or C-terminal residues (DeltaNC-PD). A mouse lethality test showed that DeltaN-PD was inactive, as is PD, whereas DeltaC-PD and DeltaNC-PD were equally active. DeltaC-PD and DeltaNC-PD, but not the other constructs formed a large SDS-resistant complex in rat synaptosomal membranes as demonstrated by SDS-polyacrylamide gel electrophoresis. When DeltaNC-PD and DeltaC-PD, both labeled with (32)P and mixed in various ratios, were incubated with membranes, eight distinct high molecular weight bands corresponding to six heteropolymers and two homopolymers were detected on a SDS-polyacrylamide gel, indicating the active toxin forms a heptameric complex. These results indicate that C-terminal processing is responsible for activation of the toxin and that it is essential for its heptamerization within the membrane.

Influence of age on the results of brachytherapy for early tongue cancer

PURPOSE

To determine the influence of elder age on the results of brachytherapy for early (T1-2 N0 M0) oral tongue cancer and examine the compatibility of low-dose rate (LDR) with high-dose rate (HDR) brachytherapy.

METHODS AND MATERIALS

We analyzed 591 patients treated at Osaka University Hospital between 1967 and 1999. We compared the results of radiotherapy for 156 elderly patients (137 LDR and 19 HDR) 65 years of age or older and 435 patients (383 LDR and 52 HDR) less than 65 years of age.

RESULTS

HDR brachytherapy showed the same local control rate as LDR brachytherapy (81% at 3 years). Elderly patients showed a poorer local control rate (75% at 3 years) than the younger group (83% at 3 years)(p = 0.002). Multivariate analysis identified age as the only prognostic factor for local control (p = 0.002).

CONCLUSIONS

HDR brachytherapy achieved the same result as LDR brachytherapy. However, the elderly patient showed a higher rate of local recurrence after brachytherapy.

Changes in performance status of elderly patients after radiotherapy

BACKGROUND

To examine the feasibility of external radiation therapy for patients 80 years old and older.

METHODS

We analyzed changes in the performance status (PS) of 1353 patients by external radiotherapy at Osaka Teishin Hospital. In addition, factors influencing PS change and interruption of treatment were assessed in patients undergoing radical and palliative radiotherapy.

RESULTS

Among elderly patients aged 80 years or more (n=67), two patients showed deterioration in PS (3%), whereas 128 (10%) did so among those 79 years old or younger. The rate of treatment completion was 90% (60/67) for patients aged 80 years and over compared with 89% (1146/1286) for younger patients. Changes in PS were more frequent for palliative treatment (improvement 83/683, 12%; deterioration 77/683, 11%) than for radical treatment (improvement 12/305, 4%; deterioration 21/305, 7%) because patients with better performance status and early disease stages underwent radical treatment. For radical radiotherapy, patients with advanced disease (stages III and IV) showed more changes (improvement 4/108, 4%; deterioration 17/108, 16%) than those with early ones (stages I and II)(improvement 7/132, 5%; deterioration 3/132, 2%) (p<0.01). Better treatment results showed a higher treatment completion rate (CR 99%, PR 86%) than poor treatment results (NC 75%, PD 50%)(p<0.01). For palliative therapy, better performance status (PS 0-2) showed a better correlation with completion of treatment (403/451 or 89%) than did poor performance status (PS 3-4)(174/ 232, 75%)(p<0.01).

CONCLUSIONS

Age is not a limiting factor for external radiation therapy. Poor performance status is a significant predisposing factor for interruption of palliative radiotherapy.

Echinophyllins C-F, new nitrogen-containing clerodane diterpenoids from Echinodorus macrophyllus

Four new nitrogen-containing clerodane diterpenoids, echinophyllins C-F (1-4), were isolated from the leaves of the Brazilian medicinal plant Echinodorus macrophyllus ("Chapéu-de-couro"), and their structures and relative stereochemistry were elucidated from their spectroscopic data. Compounds 1-4 possess an alpha,beta-unsaturated gamma-lactam ring consisting of a clerodane diterpene unit and an amine moiety.

High-dose-rate interstitial brachytherapy as a monotherapy for localized prostate cancer: treatment description and preliminary results of a phase I/II clinical trial

PURPOSE

To improve results for localized prostate cancer, a prospective clinical trial of hyperfractionated Iridium-192 high-dose-rate (HDR) brachytherapy as a monotherapy was initiated.

METHODS AND MATERIALS

Between May 1995 and September 1998, 22 implants were performed on 22 patients with localized prostate cancer (T1:T2:T3:T4 = 4:6:9:3) at Osaka University Hospital. Nineteen patients, who had T3-T4 tumors or pretreatment PSA >/= 20.0 ng/mL, received hormone therapy. No patient had external beam radiation. Transperineal needle implants using real-time ultrasound guidance were performed, followed by dose optimization program. Patients were irradiated twice a day, with a time interval of more than 6 h. Total dose was 48 Gy/8 fractions/5 days or 54 Gy/9 fractions/5 days. Acute toxicity was scored using the Radiation Therapy Oncology Group (RTOG) radiation morbidity scoring criteria. Median follow-up time was 31 months.

RESULTS

HDR brachytherapy as a monotherapy was well-tolerated. No significant intra- or peri-operative complications occurred. No patient experienced acute toxicity of grade 3 or more. PSA levels normalized in 95% of patients within 20 months after irradiation. Four-year clinical and biochemical relapse-free rates were 95% and 55%, respectively.

CONCLUSION

Acute toxicity with this method was acceptable. Further patient accrual and longer follow-up will allow comparison to other techniques.

The N-terminal prepeptide is required for the production of spore cortex-lytic enzyme from its inactive precursor during germination of Clostridium perfringens S40 spores

A spore cortex-lytic enzyme of Clostridium perfringens S40 is synthesized during sporulation as a precursor consisting of four domains. After cleavage of an N-terminal preregion and a C-terminal proregion, inactive proenzyme (termed C35) is converted to active enzyme by processing of an N-terminal prosequence with germination-specific protease (GSP) during germination. The present results demonstrated that the cleaved N-terminal prepeptide remained associated with C35. After the isolated complex was denatured and dissociated in 6 M urea solution, removal of urea regenerated a prepeptide-C35 complex which produces active enzyme when incubated with GSP. However, isolated C35 alone could not be activated by GSP. The prepeptide-C35 complex was more heat stable than active enzyme. Thus, non-covalent attachment of the prepeptide to C35 is required to assist correct folding of C35 and to stabilize its conformation, suggesting that the prepeptide functions as an intramolecular chaperone. Recombinant proteins, which have prepeptide covalently bonded to C35, were processed by GSP as well as the in vivo prepeptide-C35 complex, and the full length of the N-terminal presequence was needed to fulfil its role. Although the C-terminal prosequence is present as an independent domain which is not involved in the activation process of the enzyme, it appears that the N-terminal prosequence contributes to the regulation of enzyme activity as an inhibitor of the enzyme.

CT, MR imaging and muscle biopsy in severe crush injury

PURPOSE

We reviewed CT and MR findings in crush injuries in muscles and compared them with findings at muscle biopsy.

MATERIAL AND METHODS

CT and MR examinations were made of the lower extremities in 6 adult patients whose muscles were crushed in the big earthquake in Kobe, Japan, on 17 January 1995. All CT examinations were performed twice and within 60 days of the earthquake. In 5 of the 6 patients, biopsies were taken of the injured muscle after the CT and MR examinations.

RESULTS

At CT investigation, the images in 5 patients showed calcification in the muscles, and the crushed muscle appeared atrophic. In 3 of these 5, the degree of calcification decreased with time. At MR investigation, T1-weighted images of the crushed muscle showed isointensity in 4 of the 6 patients and high intensity in the remaining 2. T2-weighted images of the crushed muscle showed inhomogeneous high intensity in all patients. After Gd injection, all the crushed muscles were enhanced, either slightly or markedly. At muscle biopsy, in 5 of the 6 cases, the findings showed calcification in the muscle cells and the total destruction of the normal muscle structure.

CONCLUSION

CT and MR findings in crush injury correlated well with the findings at histopathology.

Medical image transmission via communication satellite: evaluation of ultrasonographic images

As compared with terrestrial circuits, communication satellites possess superior characteristics such as wide area coverage, broadcasting functions, high capacity, and resistance to disasters. Utilizing the narrow band channel (64 kbps) of the stationary communication satellite JCSAT1 located at an altitude of 36,000 km above the equator, we investigated satelliterelayed dynamic medical images transmitted by video signals, using hepatic ultrasonography as a model. We conclude that the "variable playing speed transmission scheme" proposed by us is effective for the transmission of dynamic images in the narrow band channel. This promises to permit diverse utilization and applications for purposes such as the transmission of other types of ultrasonic images as well as remotely directed medical diagnosis and treatment.

[Medical image transmission via communication satellite: evaluation of bone scintigraphy]

As compared with terrestrial circuits, the communication satellite possesses superior characteristics such as wide area coverage, broadcasting, high capacity, and robustness to disasters. Utilizing the narrow band channel (64 kbps) of the geostationary satellite JCSAT1 located at the altitude of 36,000 km above the equator, the authors investigated satellite-relayed medical images by video signals, with bone scintigraphy as a model. Each bone scintigraphy was taken by a handy-video camera, digitalized and transmitted from faculty of technology located at 25 kilometers apart from our department. Clear bone scintigraphy was obtained via satellite, as seen on the view box. Eight nuclear physicians evaluated 20 cases of bone scintigraphy. ROC (Receiver Operating Characteristic) analysis was performed between the scintigraphies on view box and via satellite by the rating method. The area under the ROC curve was 91.6 +/- 2.6% via satellite, and 93.2 +/- 2.4% on the view box and there was no significant difference between them. These results suggest that the satellite communication is very useful and effective system to send nuclear imagings to distant institutes.

[Anti-C100-3 antibody titration using 4-parameter logistic curve (results in its application to hepatitis C cases treated with interferon]

We evaluated titers of C100-3 antibody by ELISA using a 4-parameter logistic fitting curve and examined the transition of the values in the cases of interferon treatment. The 4-parameter logistic fitting curve produced a standard curve in a wider range using a micro plate reader than the logarithmic curve. The values of C100-3 antibody during and after the treatments of interferon were changed in parallel with the alterations of ALT. The anti-C100-3 antibody titers assayed in the complete or partial responders were significantly reduced at the end of interferon therapy. These findings suggest the clinical usefulness of the evaluation of anti C100-3 antibody titers.

[Oral health condition of the population in special elderly nursing home]

With the objective of making clear the oral health condition of chronic disable elderlies and thereby obtaining information for oral hygiene education and dental treatment, 77 elderlies in a special elderly nursing home attached to a private general hospital in Niigata Prefecture were studied by an interview/questionnaire method and dental examination. The following results were obtained. (1) Their mean age was 82.0 years. The major causes of chronic disability were diseases of the cerebral blood vessel and these diseases accounted for 54.5% of all diseases. The mean period of their chronic disability was 9 years. (2) 49.4% (38 persons) of them was edentulous, and 47.9% (18 persons) of them was using complete denture. (3) The average number of present teeth was 4.6 in all persons, while it was 9.0 in dentulous persons, and 3.3 of which were residual roots. (4) Salivary occult blood reaction test was positive in 87.2% in the dentulous persons and 34.2% in edentulous persons. (5) Simplified culture test using STOMASTAT was negative in 48.4% and positive in 51.6% of persons using a denture. (6) The above results indicated that dental diseases of chronic disable elderlies are not treated appropriately. This study revealed importance of dental examination, oral hygiene education and initial treatment in middle-aged and older persons.

Choroidal osteoma: two cases in Japanese women

Two cases of choroidal osteoma in otherwise healthy Japanese women are presented; the first case resembled a macular degeneration with subretinal neovascularization, the other, a diffuse amelanotic choroidal melanoma. With advanced ancillary diagnostic methods and changing concepts of prognosis and treatment of choroidal melanoma, a small atypical or doubtful choroidal melanoma should be studied carefully before hasty enucleation.