Structure and stereochemistry of brianolide,a new antiinflammatory diterpenoid from the Okinawan gorgonianBriareum sp.

Summary Brianolide (1), a new antiinflammatory diterpenoid of the briarein class, possessing a substituent at C-12 (R), has been isolated from the Okinawan gorgonianBriareum sp. Its structure has been established from spectral data in conjunction with a single crystal X-ray analysis.     

Extensive proliferation of mature connective-tissue type mast cells in vitro

There are two phenotypically distinct subpopulations of mast cells in rodents: connective tissue-type mast cells (CTMC) and mucosal mast cells (MMC). These populations differ in their location, cell size, staining characteristics, ultrastructure, mediator content and T-cell dependency. Several investigators recently reported a further subclass of mast cells which arise when normal mouse haematopoietic cells are cultured with interleukin-3 (IL-3); IL-3 is an activity similar or identical to mast-cell growth factor, histamine-producing factor, or P-cell stimulating factor. These cultured mast cells are in many ways similar to MMC; they stain with Alcian blue but not safranin, contain chondroitin sulphate E proteoglycan rather than heparin proteoglycan and have relatively low histamine content, as do MMC. Although proliferation of MMC is known to be T-cell dependent in vivo and thought to be IL-3-dependent in vitro, the factors on which CTMC proliferation depends remain elusive. Here we show that mature CTMC purified from mouse peritoneal cells can proliferate in vitro in methylcellulose culture and maintain the appearance and function of CTMC. We also present evidence that mature CTMC cannot proliferate in the presence of pure IL-3 alone.     

9-Methyl-7-bromoeudistomin D,a potent inducer of calcium release from sarcoplasmic reticulum of skeletal muscle

Summary The Ca²⁺-releasing action of several derivatives of eudistomin D isolated from a marine tunicate was compared with that of caffeine. It was found that 9-methyl-7-bromoeudistomin D was approximately 1000 times more potent than caffeine in causing Ca²⁺ release from the sarcoplasmic reticulum.The authors thank Ms A. Muroyama of this institute for her technical assistance and Prof. K. L. Rinehart of University of Illinois for his encouragement.     

Enhancing semiconductor device performance using ordered dopant arrays

As the size of semiconductor devices continues to shrink, the normally random distribution of the individual dopant atoms within the semiconductor becomes a critical factor in determining device performance--homogeneity can no longer be assumed. Here we report the fabrication of semiconductor devices in which both the number and position of the dopant atoms are precisely controlled. To achieve this, we make use of a recently developed single-ion implantation technique, which enables us to implant dopant ions one-by-one into a fine semiconductor region until the desired number is reached. Electrical measurements of the resulting transistors reveal that device-to-device fluctuations in the threshold voltage (Vth; the turn-on voltage of the device) are less for those structures with ordered dopant arrays than for those with conventional random doping. We also find that the devices with ordered dopant arrays exhibit a shift in Vth, relative to the undoped semiconductor, that is twice that for a random dopant distribution (- 0.4 V versus -0.2 V); we attribute this to the uniformity of electrostatic potential in the conducting channel region due to the ordered distribution of dopant atoms. Our results therefore serve to highlight the improvements in device performance that can be achieved through atomic-scale control of the doping process. Furthermore, ordered dopant arrays of this type may enhance the prospects for realizing silicon-based solid-state quantum computers.     

The occurrence of arachidonic acid in the venom duct of the marine snailConus textile

Summary A crude extract of the venom of the marine snailConus textile Linné caused a powerful contraction in the guinea-pig isolated ileum. The extract of the venom has been fractionated, and the fractions monitored by the contractile effect. Arachidonic acid was shown to be present as an active substance.Acknowledgment. We are grateful to Mr Z. Nagahama of Okinawa island for suppling specimens ofC. textile and to Dr T. Higashijima and Prof. T. Miyazawa (Department of Biophysics and Biochemistry, Tokyo University) for 270 MHz¹H-NMR-measurements.     

7-Chloro-3-(4-methyl-1-piperazinyl)-4H-1,2,4-benzothiadiazine-1,1-dioxide a new antihypertensive agent

Summary 7-Chloro-3-(4-methyl-1-piperazinyl)-4H-1,2,4-benzothiadiazine-1,1-dioxide (DU-717) is a new compound having sustained antihypertensive activity in a similar manner to that of hydrochlorothiazide. However, this compound shows neither diuretic nor hyperglycemic effect, being different from those of hydrochlorothiazide or diazoxide.     

Inhibition of alpha-chymotrypsin by 2-halogeno-ethanols; comparisons with 2-methyl-ethanols and urea.

2-Halogeno- and 2-methyl-ethanols inhibit alpha-chymotrypsin in the order of their substituted groups: [1] tri- greater than di- greater than mono-, [2] Br- greater than Cl- greater than CH3- greater than F-. The inhibition by the halogeno-ethanols is mediated differently from that by the methyl-ethanols, ethanol, and urea.