Escherichia coli tmRNA (10Sa RNA) in trans-translation

Here we show that Escherichia coli tmRNA (10Sa RNA) has a dual function both as an mRNA and as a tRNA in vitro. The function as a tRNA is prerequisite for the function as an mRNA. These observations strongly support the trans-translation hypothesis.     

Positron emission tomography-based boron neutron capture therapy using boronophenylalanine for high-grade gliomas: part II

Based on pharmacokinetic findings of fluorine-18-labeled L-fluoroboronophenylalanine by positron emission tomography (PET), methods for estimating tumor 10B concentration were devised. In clinical practice of boron neutron capture therapy (BNCT) for high-grade gliomas, a large amount of L-boronophenylalanine (L-10B-BPA)-fructose solution is used. Under these conditions, a slow i.v. infusion of L-10B-BPA-fructose solution should be performed for BNCT; therefore, the changes over time in 10B concentration in the target tissue were estimated by convoluting the actual time course of changes in plasma 10B concentration with a PET-based weight function including the proper rate constants [K1 (ml/g/min), k2 (min(-1)), k3 (min(-1)), and k4 (min(-1))]. With this method, the estimated values of 10B concentration in gliomas were very close to the 10B levels in surgical specimens. This demonstrated the similarity in pharmacokinetics between fluorine-18-labeled L-fluoroboronophenylalanine and L-10B-BPA. This method, using the appropriate rate constant, permits the determination of tumor 10B concentration and is widely suitable for clinical BNCT, because the averaged PET data are enough to use in future patients without individual PET study.     

Abdominal surgery for patients on maintenance hemodialysis

PURPOSE: To evaluate the performance of the new perimetric threshold strategy SITA relative to older methods. METHOD: Thirty-two patients with either glaucoma or ocular hypertension performed two threshold visual field tests with each of three threshold strategies, SITA, Humphrey Full Threshold, and Fastpac. Testing was distributed over three visits, and testing order was balanced between strategies to control for order effects. RESULTS: SITA tests consumed 54% of the time taken by Full Threshold tests on average, and 85% of Fastpac tests; SITA's test times were significantly shorter than those of Full Threshold (p<0.0001) and Fastpac (p=0.0008). Test-retest threshold variability did not differ significantly between strategies. Intertest variability of the pattern deviation analysis was lowest in SITA (p<0.01) relative to both Full Threshold and Fastpac. Both SITA and Fastpac showed higher than expected average sensitivities relative to Full Threshold. SITA and Fastpac showed approximately the same amount of visual field loss. There was a significant relationship between Mean Deviation and the SITA function used to shorten stimulus sequences at points where measurement errors are small (p<0.0001). CONCLUSION: Our results suggest that SITA matches the precision of older thresholding methods, consuming considerably and significantly less test time. This indicates that SITA could replace Full Threshold as the standard clinical test used in glaucoma management, without decreasing the quality of test results.     

Production and characterization of recombinant tachycitin, the Cys-rich chitin-binding protein

Tachycitin is an invertebrate chitin-binding protein with anamidated C-terminus, and possesses antimicrobial activity againstboth fungi and bacteria. The ¹H-NMR-based tertiary structureof tachycitin was recently determined [Suetake et al. (2000)J. Biol. Chem., 275, 17929–17932]. In order to examinethe structural and functional features of tachycitin more closely,we performed for the first time, gene expression, refolding,¹⁵N-NMR-based characterizations, and antimicrobial activitymeasurements of a recombinant tachycitin (rTcn) that does nothave the amide group at the C-terminus. The NMR analysis indicatedthat rTcn possesses the same structural construction as thenative tachycitin. The backbone ¹⁵N relaxation measurementsshowed that the molecular motional correlation time of rTcnincreases as its concentration increases, indicating that tachycitinshave a tendency to aggregate with each other. rTcn exhibitsantimicrobial activity against fungi but not against bacteria.The cell surface of fungi contains chitin as an essential constituent,but that of bacteria does not. These results suggest that notonly the chitin-binding region but also the C-terminal amidegroup of tachycitin plays a significant role in its antimicrobialproperties.     

Zonal adult Hirschsprung's disease

BACKGROUND: Hirschsprung's disease is a congenital disorder which is rare in adulthood. In typical cases the aganglionosis involves mainly the rectum or rectosigmoid colon and the lesion starts from the anal valve. Zonal segmental aganglionosis is a very rare type even in children. PATIENT: A 54 year old women with zonal segmental aganglionosis had an aganglionic segment 18 cm in length located in the rectosigmoid colon with an 8 cm long normal appearing rectum and dilated proximal colon. Resection of the stenotic segment with end to end anastomosis was performed. CONCLUSION: The functional result was excellent five years after the operation.     

A repeated-dose dermal toxicity study of hydrophobically modified hydroxypropyl methylcellulose in rats

A six-month repeated-dose dermal toxicity study followed by a 30-day recovery test of hydrophobically modified hydroxypropyl methylcellulose (HM-HPMC), a new cellulose derivative used as a thickener for topical pharmaceuticals, was conducted using rats. Aqueous paste of HM-HPMC was applied to the skin of rats once daily at dose levels up to 60 mg/kg/day, which was the highest dose that could be administered. Items checked included general signs, urinalysis, hematology, ophthalmology, and histopathology. One rat died during the administration period owing to a malignant tumor in the hemopoietic system, which was not attributed to the test substance. Statistically significant differences were found in some test results, but those were not dose-dependent and were considered to be incidental or spontaneous. It was concluded that the test substance was not toxic upon chronic dermal administration at dose levels up to 60 mg/kg/day.     

Anti-tumor effects of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) in seborrheic keratosis

1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is a drug with potent antiproliferative action on keratinocytes that have nuclear receptors for 1,25(OH)2D3. We investigated the effects of 1,25(OH)2D3 on widespread seborrheic keratoses in 51 patients with these tumors. The data indicated that resolution of these tumors was dependent on both tumor size and dose of 1,25(OH)2D3. Among 15 patients treated with a high dose (0.5 microgram/d) of oral 1,25(OH)2D3, the lesions of widespread seborrheic keratoses changed from brown-black papules to brownish papules with erythema and/or crust as early as 2 wk after the start of treatment. The tumors finally developed into an atrophic scar or brownish pigmented macule. Histologically, vacuolation of the spinous cells, vesicle formation, and liquefaction degeneration of the basaloid cells were observed. Numerous lymphocytes had infiltrated in the papillary dermis. Among 36 patients treated with a low dose (0.25 microgram/d) of 1,25(OH)2D3, brownish papules became pale to normal in color and reduced in size, without erythematous change. Histologically, acanthosis of the epidermis was reduced, but degenerative change of the tumor cells was not observed. These data suggest that oral therapy of 1,25(OH)2D3 is an acceptable method well suited to the removal of seborrheic keratoses, especially those that are predominantly small tumors.     

Space-dependent analysis of BWR core nuclear thermal hydraulic instability and thermal margin

Nuclear thermal hydraulic oscillations in BWR cores were analyzed by the space-dependent BWR core transient program STANDY. In a simulation of instability in the Lasalle-2 unit, the oscillations that caused a scram were successfully reproduced. The maximum thermal margin decrement was far smaller than the initial margin, and significant margin to thermal limits existed at the time of scram. An analysis of hypothetical control rod insertion suggested that the oscillations could have been suppressed by only a few control rods. Analyses of a core destabilized by various parameters were also carried out to examine thermal margin sensitivity during the oscillations. The results showed that, regardless of which parameters were assumed to make the core unstable, thermal margin changes were substantially smaller than the initial margin expected under operation conditions to cause an instability.