A relationship between the mevalonate pathway and isoprenoid production in actinomycetes

Most Streptomyces strains are equipped with only the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for the formation of isopentenyl diphosphate. In addition to this pathway, some Strepromyces strains have the mevalonate pathway to produce terpenoid antibiotics. We have previously shown that a gene cluster for biosynthesis of terpentecin, a diterpene antibiotic, was located in adjacent the mevalonate pathway gene cluster. In this study, a mevalonate pathway gene cluster was cloned from Actinoplanes sp. strain A40644, an isoprenoid antibiotic BE-40644 producer, to examine whether the mevalonate pathway genes and isoprenoid biosynthetic genes are clustered in genomic DNA. By sequencing flanking regions a probable BE-40644 biosynthetic gene cluster was found in the downstream region of the mevalonate pathway gene cluster. Heterologous expression of a 9-kb fragment confirmed that a set of the BE-40644 biosynthetic genes was involved in the fragment. This result suggested that the presence of the mevalonate pathway might be a good landmark to detect the production of isoprenoid compounds by actinomycetes.     

Strain difference in the susceptibility of thymocytes to radiation-induced apoptosis: in vitro study.

The susceptibility of thymocytes from STS/A to radiation-induced cell death was compared with that of thymocytes from BALB/cHeA. After in vitro exposure to 12 Gy X-ray, thymocytes were incubated at 37 degrees C for 8 h and then cell mortality was assessed by 0.02% erythrosin B exclusion. Cell death took place from 2 h in the incubation period, reaching a maximum at 6 h for both strains. The dose-effect on cell death at 4 h of incubation was examined after 1-24 Gy of X-irradiation. An increase in cell death was detectable even at 1 Gy in both strains. The number of dead cells in BALB/cHeA gradually increased with doses of more than 1 Gy, finally to a maximum (approximately 60%) in the dose range of 8-12 Gy, whereas the maximum cell death in STS/A was approximately 40%. The difference between the strains at maximum cell death was significant (P less than 0.005). The difference in the radiosensitivity of thymocytes between the two strains could not be attributed to a difference in the composition of their subpopulations because flow cytometric analysis based on the expression of CD4 and CD8 showed no intrinsic difference in the thymocyte subpopulations of BALB/cHeA and STS/A.     

Lymph node metastasis, recurrence, and prognosis in small peripheral lung adenocarcinoma

OBJECTIVE: We studied clinical and pathological features of small peripheral adenocarcinoma of the lung, focusing on tumor typing based on Noguchi's classification of small adenocarcinoma and determining whether these tumors grew by replacing alveolar lining cells. METHODS: Subjects were 51 patients with small peripheral adenocarcinoma 2 cm or less in diameter resected between 1994 and 2001. Mediastinal and hilar lymph node dissection was done in 37 (72.5%). Patients were divided into 2 groups by replacement or nonreplacement tumors. We compared patient profiles, lymph node involvement, and recurrence and survival patterns. RESULTS: No significant difference was seen between groups in mean age, surgical procedure, or primary tumor location. Women predominated in replacement tumors at 71% vs 41%, p = 0.04. The incidence of lymph node metastasis at 40% vs 4.5%, p = 0.007 and distant metastasis at 47% vs 2.9%, p < 0.001 was significantly higher in nonreplacement than replacement tumors. Replacements tumor thus showed significantly better disease-free survival at 95% vs 53%, p < 0.001, and overall 3-year survival at 95.4% vs 62.7% than did nonreplacement tumors. CONCLUSION: We found distant metastasis and lymph node involvement to be more frequent in nonreplacement than replacement small peripheral adenocarcinoma, on suggesting that pretreatment tumor typing and accurate nodal status determination are essential to improve disease staging.     

Adenocarcinoma Arising in the Retrorectal Space: Report of a Case

(Received for publication on June 27, 1996; accepted on Mar. 4, 1997)     

Drug delivery system using microspheres that contain tacrolimus in porcine small bowel transplantation

Rejection remains a major barrier to successful bowel transplantation, in spite of improved immunosuppressive techniques. Therefore, new, more effective, immunosuppressants, with fewer side effects, are needed. Biodegradable microspheres containing tacrolimus (FK506) were used in an experimental porcine small bowel transplantation. Twenty pigs underwent transplantation and were divided into four groups according to the immunosuppressive regimen. Group A (n=5): no immunosuppression; group B (n=6): 0.2 mg/kg per day of FK506; group C (n=3): 1.0 mg/kg per day of FK506; group D (n=6): 0.04 mg/kg per day of FK506 contained in biodegradable microspheres. Rejection was diagnosed macroscopically by endoscopic examination and histologically by biopsy specimen analysis. The mean survival time and standard deviation (SD) were 8.8±3.5, 11.0±1.4, 9.7±2.5 and 28.6±22.5 days for groups A, B, C, and D, respectively, with a statistically significant difference found between group D, on the one hand, and groups A, B and C, on the other. The mean trough blood concentration of FK506 was 10.5±2.2, 27.9±6.0 and 10.5±3.5 ng/ml in groups B, C and D, respectively. In groups A and B, all pigs died of rejection, without infection. In group C, all died of infection, without rejection. In contrast, none of the pigs in group D developed rejection or infection. Our results clearly show that the drug delivery system using biodegradable microspheres that contain FK506 is effective for controlling rejection with fewer side effects in the porcine small bowel transplantation.     

Objective evaluation of the mandibular position by the change in the function of the middle ear. 1. Centric relation and lateral eccentric position

Tympanometric measurement has been made on centric relation and working side and non-working side in 19 healthy subjects (12 males and 7 females aged 23-27) and the following conclusions have been obtained: 1. The Tympanogram in the healthy subjects showed a symmetrical pattern, being of type A bilaterally, in all the cases, and no lateral or sexual difference was seen any item of measurement. 2. S. C. value increased in order of centric relation, working side and non-working side, but decreased in IMP., PRS. and EAC.. 3. Significant differences were observed in the items of measurement regarding S. C. and IMP. all between centic relation and working side, centric relation and non-working side, working side and non-working side. These findings show a correlation between the function of middle ear and the horizontal mandibular position. Therefore these findings suggest the possibility of tympanometric measurement becoming one of the parameters as the method for objective evaluation of the mandibular position as the change in the function of the middle ear.