Dependence on the lipophilicity of maleimide derivatives in their inhibitory action upon chemotaxis in neutrophils

Summary Modification of polymorphonuclear neutrophils by a series of maleimide derivatives with various degrees of lipophilicity and hydrophilicity indicated that hydrophilic reagents had little effect on chemotaxis, whereas the degree of the inhibitory effect of lipophilic reagents on the chemotaxis was parallel to the degree of their lipophilicity.This work was supported in part by a grant-in-aid for Scientific Research (No.267043) from the Ministry of Education, Science and Culture, Japan, awarded to T.Y.     

Microbial methylation of benzenethiols and release of methylthiobenzenes

Summary Three phylogenetically diverse microorganisms methylated several different chloro- and nitro-substituted benzenethiols to yield the corresponding methylthiobenzenes. These products were identified by gas chromatography-mass spectrometry. In several cases large percentages of the methylthio products were released by intact cells into the medium, suggesting that microbial methylation of xenobiotic thiols may be a significant biotransformation in many ecosystems.Acknowledgments. This investigation was supported by research grant ES 02639 from the National Institute for Environmental Health Sciences, and an equipment grant (RR07013) from the Biomedical Research Support grant program. Division of Research Resource, NIH. We thank Steve Hawthorne for assistance in performing GC-MS analyses.     

Tumorigenic activity of cloned polyoma virus DNA in newborn rats

Summary The proximal portion of the polyoma virus early region as well as the complete viral genome were cloned in pBR322. Recombinant plasmids induced tumors in newborn rats but only after linearization of the DNA by various restriction endonucleases.This work was financed by grant MA-6731 from the Medical Research Council and by a grant from the National Cancer Institute of Canada.     

Failure of cilia of reprogram following segmental ampullary reversal of the rabbit oviduct

Summary Cilia exhibited unidirectional and coordinated movement within microsurgically reversed segments of rabbit ampulla when examined up to 13 months after surgery. The direction of ciliary beating was opposite that of the remainder of the oviduct.This research was supported in part by a grant (HD 09339-06) from the National Institutes of Health and the Bioassay and Smooth Muscle Core Laboratories (NIH grant P30 HD10202).     

Assay of aminoglycosides is influenced by tissue homogenization technique

Summary Recovery of neomycin from tissue homogenates was lower when glass/glass homogenizers were used due to the abrasion of glass which will bind to the drug. Glass homogenizers should be avoided for the determination of aminoglycoside levels in tissues.Acknowledgment. Supported by research grant NS-13792 and Program Project grant NS-05785 from the National Institutes of Health.     

Baroreceptor reflex sensitivity after acute blood volume expansion in anesthetized dogs

Summary Changes in heart rate resulting from mechanically induced changes in arterial blood pressure were used as a measure of baroreflex sensitivity. This sensitivity was shown to be decreased after volume expansion.This work was supported in part by PHS grant HL-23239 and a grant from the Central Ohio Heart Chapter of the American Heart Association.     

Effects of diethylstilbestrol on the production of various extracellular products of Staphylococcus aureus

Summary The synthetic estrogen diethylstilbestrol at a subinhibitory level of 1.75 g/ml diminished the production of staphylococcal alpha toxin, coagulase, deoxyribonuclease and penicillinase. Thus, the reported host beneficial effects of diethylstilbestrol may be partially related to its retardive action of certain toxins, or enzymes of S. aureus.Acknowledgments. This work was supported by United States Public Health Service, grant AI 06618, a grant in aid from Loyola University, United States Public Health Service, grant GRSG PRO 5368, and grants from Eli Lilly, Upjohn, Syntex, and G. D. Searle drug companies.     

Effect of testosterone on the hypothalamic-pituitary-gonadal axis of pinealectomized and pineal-intact male rats

Summary Previous studies indicate that steroid hormones alter pineal biochemistry, and it has been suggested that at least part of the negative feedback effect of steroid hormones on pituitary gonadotropin release may be mediated by the pineal gland. In this study, pinealectomy did not alter the inhibitory effect of testosterone on neuroendocrine-gonadal activity in the male rat, suggesting that the pineal gland does not mediate the response of the rat hypothalamic-pituitary axis to testosterone.We wish to thank Susan H. Losee, Brigitte G. Mann and John Georgeson for excellent technical assistance. This investigation was supported by NSF grant SER 77-03836 and a grant from the University of Wisconsin-Parkside Committee on Research to E.P.W. and by NIH grant HD-09885 and NSF grant PCM 76-09955 to F.W.T.     

Increased blood pressure in the SHR is not related to a deficit in renomedullary PGE2

Summary Synthesis of prostaglandin E₂ by renal medulla from SHR and WKY rats was compared during early postnatal development. Although arterial blood pressure was significantly higher in SHR as early as 6 weeks of age, no difference in renal medullary prostaglandin synthesis was observed.Supported in part by a grant from the michigan Heart Association and NIH grant AM-10913.     

Effect of stress on choline acetyltransferase activity of the brain and the adrenal of the rat

Choline acetyltransferase (ChAT) activity was determined in cerebral cortex, hypothalamus, hippocampus, cerebellum, medulla oblongata, midbrain and adrenal gland of rats exposed to acute or chronic stress. The exposure of animals to acute immobilization and cold stress (4°C) for one hour resulted in a significant decline of ChAT activity in all brain regions examined except for the medulla oblongata. Moreover, the exposure to acute stress resulted in significant increase of the same enzyme in the adrenal gland. However, chronic exposure of animals to cold stress (4°C) for 7 days resulted in no significant changes of ChAT activity in all tissues examined except for a decline in the midbrain and an increase in the medulla oblongata. The administration of corticosterone (2.0 mg/kg) 1 h prior to sacrificing caused an effect similar to that of acute stress on ChAT activity in all brain regions except for the hypothalamus and the cerebellum. It was concluded from this experiment that stress-induced changes in the ChAT activity of specific brain regions might be mediated by the adrenal steroids.This work was supported by a grant from the National Aeronautics and Space Administration (NSG 2183 and NAG 2-411), a grant from the National Institutes of Health (NIH RR 0811) and a grant from the Division of Research Resources (NIH grant RR 03020).     

Pressure-induced variations of K+-permeability as related to a possible reversible electrical breakdown in human erythrocytes

Summary Above a hydrostatic pressure of about 600 b a pronounced reversible increase in the net K⁺-efflux from human erythrocytes is observed. The effect is explained in terms of an electro-mechanical compression of the membrane, resulting in a reversible breakdown of the membrane.Acknowledgments. This work was supported by a grant from the Sonderforschungsbereich 160 to U.Z. and by grant No.2.4511.76 from the FRFC to R.G.     

Experimental formation of podocytes in the parietal layer of the Bowman's capsule

Summary A metaplasic transformation of the parietal layer of the Bowman's capsule into podocytes is described in glomerular cysts induced by postnatal injection of methylprednisolone acetate to rabbits. Both the anomalous location of podocytes and their utility for the study of the biology of these cells are discussed.This work was supported by a grant of the Fondo Nacional para el Desarrollo de la Investigación Cientifica from the spanish-government and a grant from the Marcelino Botín Foundation, Santander, Spain.     

Dependence on the lipophilicity of maleimide derivatives in their inhibitory action upon chemotaxis in neutrophils.

Modification of polymorphonuclear neutrophils by a series of maleimide derivatives with various degrees of lipophilicity and hydrophilicity indicated that hydrophilic reagents had little effect on chemotaxis, whereas the degree of the inhibitory effect of lipophilic reagents on the chemotaxis was parallel to the degree of their lipophilicity.     

Binding capacities of various analogues of S-adenosyl-L-homocysteine to protein methyltransferase II from human erythrocytes

Summary A series of analogues of S-adenosyl-L-homocysteine, modified mainly in the amino acid portion of the molecule, have been synthesized. All were found to be competitive inhibitors of protein methyltransferase II from human erythrocytes. S-adenosyl-L-homocysteine remains however by far the most effective inhibitor of the methylase.Acknowledgments. This work was supported by a grant of the Fonds National Belge de la Recherche Scientifique and by a grant of the Fonds Emile Defay.     

Liver esterase abnormalities in hereditary neurological diseases of mice

Zusammenfassung Alle von uns in Mäusen untersuchten vererblichen neurologischen Erkrankungen stellen entweder primäre oder sekundäre gesamtkörperliche Prozesse dar. Verschiedene allelische Substitutionen produzieren spezifische Leber-Esterase-Isozym-Defekte.

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This work was supported in part by NIH research grant No. NB 06448 from the National Institute of Neurological Diseases nad Stroke, a grant from the National Foundation for Neuromuscular Diseases, Inc., a grant from the Health Research Fund, United Fund of Schenectedy County, Inc., and an allocation from NIH General Research Support Grant No. RR 05545 from the Division of Research Resources to The Jackson Laboratory.

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The principles of laboratory animal care as promulgated by the National Society for Medical Research are observed in this Laboratory.     

Precocious puberty in rats induced by hypothalamic lesions: A comparison of platinum and stainless steel electrodes

Summary Precocious sexual maturation was induced in immature female rats by 2 types of unilateral hypothalamic lesions. Stainless steel electrodes produced smaller tissue defects but proved more efficient than platinum electrodes.Supported by Swiss National Science Foundation grant No. 3.016.73.Supported by Canadian Medical Research Council grant No. MT 4192.Supported by a contribution from the Roche Research Foundation for Scientific Exchange and Biomedical Collaboration with Switzerland     

Activation of complement by trypanosomes

Summary Factors exhibiting anti-complementary activity released from trypanosomes after incubation at 20°C were described. The active material was shown to consume the first component of bovine complement. While the anticomplementary factor(s) from T. lewisi could activate bovine, human and guinea pig complement, the factor(s) from T. congolense was observed to activate bovine complement, but not guinea pig and only slightly human complement. The roles of complement activating factor(s) of trypanosomes in the pathology of the disease are discussed.This project is supported by National Research Council of Canada grant A 0068 and a grant from the International Development Research Centre.     

The effect of postnatal undernourishment on epileptiform kindling of dorsal hippocampus

Summary Rats were undernourished postnatally from birth through 20 days of age. They were subsequently tested for susceptibility to motor seizures kindled in hippocampus in adulthood. Compared to littermate control animals the postnatally undernourished rats were more susceptible to the kindling treatment. We conclude that early postnatal undernourishment has a permanent effect on susceptibility of the hippocampus to electrically-induced seizures.This work was supported by Public Health Service grant NS 13799, National Science Foundation grant GB 35532, and by Hoffman-LaRoche, Inc.     

Demonstration of lateral asymmetry in G-banded mouse embryo chromosomes

Summary Cells obtained from 10-day mouse embryos were cultured for 3 h in medium containing colcemid. Chromosome preparations were subjected to G-banding in either calcium-magnesium free Hank's solution or the ASG method. From one to several occurrences of lateral asymmetry (unequal banding of sister chromatids) were observed in the majority of karyotypes analyzed.Partial support for this study was provided by grant no. 2-PO1-ES00226-10, NIH, NIEHS and by a grant from the National Foundation-March of Dimes. We thank Don Driscoll for his capable assistance.     

Visual responses in the central nervous system of the scallopPecten ziczac

Summary Electrical activity recorded from the lateral lobe of the visceroparietal ganglion in the scallop Pecten ziczac reflects predominatly the visual response to onset of light stimulation, suggesting that shadow reflex mechanisms likely occur elsewhere within the central nervous system.We thank Wolfgang Sterrer and the Bermude Biological Station for their cooperation and the use of their facilities. Support was, in part, from an NSF grant to the BBS (PCM 76.13459) and from an NIH grant (NS 12971). This paper is a contribution from the Bermuda Biological Station (No. 708) and the Tallahassee, Sopchoppy and Gulf Coast Marine Biological Association (No. 84).