No abstract

A nonpeptidyl secretagogue for growth hormone of the structure 3-amino-3-methyl-N-(2,3,4,5-tetrahydro-2-oxo-1-([2'-(1H-tetrazol-5 -yl) (1,1'-biphenyl)-4-yl]methyl)-1H-1-benzazepin-3(R)-yl)-butanamid e (L-692,429) has been identified. L-692,429 synergizes with the natural growth hormone secretagogue growth hormone-releasing hormone and acts through an alternative signal transduction pathway. The mechanism of action of L-692,429 and studies with peptidyl and nonpeptidyl antagonists suggest that this molecule is a mimic of the growth hormone-releasing hexapeptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6). L-692,429 is an example of a nonpeptidyl specific secretagogue for growth hormone.

The treatment of periodontal disease has been largely directed at the microbiological etiology. The prevention of bone loss by modulating the host response to the bacteria may be a useful adjunctive method in the management of periodontitis. Alendronate, an amino bisphosphonate, may inhibit bone loss in osteolytic diseases by altering osteoclast activity. The objective of this double-blind study was to evaluate alendronate inhibition of alveolar bone loss in the naturally occurring beagle dog model of periodontitis. Sixteen 7 to 9 year old beagles with moderate-to-severe periodontitis were studied for 6 months. The dogs were stratified into two groups based on initial periodontal severity. One group received 3.0 mg/kg alendronate weekly orally and the other group received a placebo. Silk ligatures were placed on the study teeth for the first 3 months of the study to exacerbate the periodontal destruction. Clinical data were collected for attachment level, gingival index, plaque index, and mobility at baseline and one-month intervals. Intraoral radiographs were made at baseline and at 3 and 6 months. The mandibles were processed for histology at month 6. The radiographs were analyzed by digital image analysis of the subtracted images. A statistically significant difference in bone mass (P < 0.001) was observed between the alendronate and placebo groups. The bisphosphonate had no effect on the clinical parameters of gingival inflammation or plaque. A trend toward decreased attachment loss and mobility was observed in favor of the alendronate group.(ABSTRACT TRUNCATED AT 250 WORDS)

Acidified 2,2-dimethoxypropane was used to chemically dehydrate biologic tissues for examination in the electron microscope. The ultrastructural integrities of single-celled algae, plant tissues (cotyledon, root, leaf) and animal tissues (liver, pancreas, muscle, cartilage) were maintained. Our technique was simpler and quicker than physically exchanging water for organic solvents (e.g., acetone, ethanol) as generally performed in microscopy.

Summary. Spherosomes of cotyledons of germinating peanuts (Arachis hypogea L.) were examined by electron microscopy and found to be particles about 1.0 to 2.0 ,u in diameter bounded 4The abbreviation used is: FACS, fatty acyl-CoA synthetase. at 1.5,000 X g for 20 minutes to prodtuce a creamy band or fat pad on the surface of the supernatanit liqluid, the sutpernatant liquid an(d a pellet. The fat pa(l was removed with a spatula and resuispende(d in 15 ml of 0.25 M stucrose. This sulspension and the suiperulatant liquiiid were centrifuged againi at 1.5,000 X q for 20 minuites. The restultant pellets were combined with the previouls pellet, resuispen(le(d in 7 ml of 0.25 M sucrose and( designated the mitochond(rial fraction. The 2 liquid( supernatants were also combined. The washed spherosomes (fat pad) were resuspended in 7 ml of 0.25 M sucrose.Spherosomal fractions prepared for chemical analysis were washed with distilled water instead of the 0.25 -i sucrose.Electron Microscopy. Isolated spherosomes were embedded in an agar medium to facilitate manipulation through the fixation procedures. The spherosomal fraction was mixed with a 2 % (w/v) soltution of agar at 430 and centrifuged at 2600 X g until the agar gelled. Half mm3 cuibes of the gel which contained the spherosomes were removed from the centrifuge ttube and taken throuigh the fixation process.Fixation was accomplished by 1 of 3 procedlures. The material was fixed in: i) aquleouis 2 % potassiuim permanganate at 00 for 1 hour, ii) 2 % osmium tetroxide solution in 0.1 Mi phosphate buiffer, pH 7.2, overnight, iii) 6 % gluitaraldehyde in 0.3 M sucrose containing 0.1 M phosphate buffer, pH 7.2, overnight. It was then serially dehydrated in aqueous acetone. The first 2 preparations were embedded in Maraglas (5). The dehydrated, glutaraldehyde-fixed preparation was transferred to hexane and rinsed thoroughly. This defatted material was then serially hydrated, fixed in 2 % osmium tetroxide in 0.1 M phosphate buffer, pH 585 www.plantphysiol.org on May 9, 2018 -Published by Downloaded from