Methionine enkephalin as a possible neuromodulator of regional cerebral blood flow

Summary In swine, cerebral blood flow was documented by a left ventricular injection of radiolabeled 15-micron spheres. Utilizing this procedure, the effect of the putative neurotransmitter methionine-enkephalin on regional cerebral blood flow was systemically evaluated. Our results revealed that a peripheral infusion of methionine enkephalin into miniature swine significantly increased cerebral blood flow in the basal ganglia, cerebellum, pons, inferior parietal cortex, superior parietal cortex and frontal cortex. Non-significant increases were observed in the hippocampus, occipital cortex and medulla oblongata while no effect on blood flow was observed in the pituitary gland. Significance of these results reside in the potential role of methionine enkephalin as a modulator of blood flow to the brain.     

Potential aldose reductase inhibitors: 1,2,4-triazolidine-3,5-diones and 2-(3,4,5-trimethoxybenzoyl)-4,4-diethyl-3,5-isoxazolidinedione

1,2,4-Triazolidine-3,5-diones and the 3,5-isoxazolidinedione were, observed to be, potent inhibitors of rat lens aldose reductase activity. In vivo in streptozotocin-diabetic rats, selected agents at 20 mg/kg/day, orally for 21 days reduced significantly the sorbitol levels of rbc, lens and sciatic nerves, suggesting that these derivatives may have some usefulness to treat clinical complications of diabetes mellitus.     

聚合物的一维振子链模型

一维聚合链可以用一维振子链来模拟.其中联接振子而组装链的键可以分为主键和次键.一维振子链的非线性过程要受主键或次键的非线性过程所控制,本文讨论了在主键或次键的非线性作用下所引起的一维振子链的非线性过程.在一定条件下,我们可以得到解析的孤子解.     

Somatostatin immunoneutralization overcomes the inhibitory effects of quipazine and pargyline on growth hormone secretion in domestic fowl

Summary The inhibitory effects of pargyline and quipazine on chicken growth hormone secretion were overcome by passive immunoneutralization of endogenous somatostatin (SRIF)-14 or SRIF-28(1–14)-like immunoreactivity. Administration of the specific antisera to control birds pretreated with 0.9% NaCl elevated the basal plasma GH concentrations. These results suggest that peptides with SRIF-14 or SRIF-28(1–14)-like immunoreactivity tonically inhibit GH secretion and are at least partially responsible for the inhibitory effects of pargyline and quipazine on GH release in immature domestic fowl.     

Action potential mutations stop a biological clock in Drosophila

The Drosophila melanogaster male produces a species-specific courtship song by wing vibration. The most conspicuous feature of the song is a series of pulses with a 30-40-ms interpulse interval (IPI) which oscillate in wild-type males with a period of 50-60 s. This short-term biological rhythm in IPI is influenced by several gene mutations at the period (per) locus, which alter the normal 24-h free-running period of the circadian clock and have corresponding effects on the song cycle. The present study reveals that, under restrictive conditions, temperature-sensitive mutations which affect neuronal membrane excitability seem to stop the biological clock underlying the fruitfly's song rhythm.     

Evidence from mitochondrial DNA that African honey bees spread as continuous maternal lineages

African honey bees have populated much of South and Central America and will soon enter the United States. The mechanism by which they have spread is controversial. Africanization may be largely the result of paternal gene flow into extant European populations or, alternatively, of maternal migration of feral swarms that have maintained an African genetic integrity. We have been using both mitochondrial and nuclear DNA restriction fragment length polymorphisms to follow the population dynamics between European and African bees. In earlier reports, we suggested that if African honey bees had distinctive mitochondrial (mt) DNA, then it could potentially distinguish the relative contributions of swarming and mating to the Africanization process. Because mtDNA is maternally inherited, it would not be transmitted by mating drones and only transported by queens accompanying swarms. Furthermore, the presence of African mtDNA would reflect unbroken maternal lineages from the original bees introduced from Africa. The value of mtDNA for population studies in general has been reviewed recently. Here we report that 19 feral swarms, randomly caught in Mexico, all carried African mtDNA. Thus, the migrating force of the African honey bee in the American tropics consists of continuous African maternal lineages spreading as swarms. The mating of African drones to European queens seems to contribute little to African bee migration.     

X-ray microanalysis of mast cells in rat's muscle

Summary Mast cells from rat's tongue muscles, fixed with glutaraldehyde only, were examined with an electron microscopic microanalyzer — the EMMA-4. With the preparatory method used, high emissions of a number of elements were obtained in various intracellular spots. The granules of mast cells were found to contain strictly localized high concentrations of sulphur, calcium and zinc.This work was supported by a grant from the MRC. Funds for the purchase and running cost of the instrumentation were provied by the SRC.     

Experimental hypertension elicited by injections of methyl cellulose

Résumé Des injections sous-cutanés d'une solution de méthyl-cellulose provoquent dans la rate une vraie hypertension artérielle maligne. Les animaux utilisés eurent fréquemment des dèmes et des ascites et toujours des lésions artérielles dans le cur, les reins et ailleurs.

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This study was supported by grants H-2703 and H-4327 from the United States Public Health Service.