Gonadal steroids have paradoxical effects on brain oxytocin receptors

Specific brain receptors for oxytocin have been described in several mammalian species. The distribution of these receptors differs greatly across species and in the rat, receptor binding in specific brain regions appears to depend upon gonadal steroids. This study used in vitro receptor autoradiography to examine the effects of testosterone on oxytocin receptor binding in the mouse forebrain. Three groups of male mice were compared: castrates treated with blank capsules, castrates treated with testosterone filled capsules, and intact males. Irrespective of steroid treatment, the distribution of oxytocin receptors in mouse forebrain differed markedly from patterns previously described in the rat. In addition to these species differences in receptor distribution, testosterone had effects in the mouse which differed from the induction of receptors previously reported in the rat. In the mouse ventromedial nucleus of the hypothalamus, binding in the untreated castrate males was approximately double that observed in either the intact or the testosterone-treated castrates. In other regions of the mouse brain, such as the intermediate zone of the lateral septum, binding to oxytocin receptors was increased with testosterone treatment. These results suggest that the brain oxytocin receptor varies across species not only in its distribution but also in its regional regulation by gonadal steroids. These apparently paradoxical changes in oxytocin receptor binding may result from either direct or indirect effects of gonadal steroids in mouse brain.     

Isoforms p69 and p100 of 2'',5''-oligoadenylate synthetase induced differentially by interferons in vivo and in vitro

There is no better place to test life-saving resuscitation interventions than in the prehospital setting. Patients rarely survive cardiac arrest if resuscitation techniques have failed before leaving the scene. Also, paramedics are usually very experienced in key initial resuscitative techniques, and they routinely operate under strict paramilitary protocol, resulting in better study compliance. In addition, the large study populations that are derived from emergency medical services (EMS) systems lead to faster study completion and statistically stronger data. Most important, by reinforcing standardized care, rigidly scrutinized trials improve patient care, regardless of the effect of the study intervention. The success of productive EMS research centers requires routine communication between hospital and EMS administrators and their medical directors, designation of mutually acceptable data collectors who guarantee confidentiality, reciprocal exchange of study data provided as educational seminars to the hospitals, commitments to support the budget requests of an EMS program and appropriate system modifications, inclusion of EMS personnel in study design from the very beginning, prospective education of the medical community and media before protocol implementation, an authoritative grassroots medical director, and a paramedic supervisor system.     

HOW EVOLUTIONARY IS SCHUMPETER'S THEORY OF ECONOMIC DEVELOPMENT?

The generic features of an evolutionary theory which are identified in the conceptional discussion of the present paper can be shown to be present already in Schumpeter's 1912 work, The Theory of Economic Development . None the less, it is argued that Schumpeter fell short of a level of generality by which he would have succeeded in providing a true foundation for evolutionary economics. The reason is his eagerness--very clearly visible in the "lost" seventh chapter--to align his theory with the economic reasoning of contemporary "pure" economic theory that was moulded in an equilibrium-oriented heuristic and the methodology of comparative statics. Schumpeter's conception--which, in opposing the idea of borrowing from Darwinian thought, he called "development"--is rather a special theory of the unsteady capitalist growth process passing through booms and crises. Throughout all of Schumpeter's writings the notion of development is therefore closely related to the business cycle phenomenon. The paper argues that this special framing implies not only some arbitrary hypotheses which are difficult to accept in an evolutionary interpretation, but also some limitations in his understanding of (what he refused to call) economic evolution, particularly with respect to its driving forces.     

Modified CIELAB formula tested using a textile pass/fail data set

The proposed new color-difference formula of CIE TC 129, which is a modified version of CIELAB, was tested with a recently published data set of textile pass/fail judgments. Goodness of fit is improved, if the parameter of lightness is set near 2, and if, additionally, a weight function for lightness is defined that reduces the weight of a lightness difference with lightness level in relation to chroma or hue scaling. © 1994 John Wiley & Sons, Inc.     

6-Phospho-{beta}-galactosidases of Gram-positive and 6-phospho-{beta}-glucosidase B of Gram-negative bacteria: comparison of structure and function by kinetic and immunological methods and mutagenesis of the lacG gene of staphylococcus aureus

The 6-phospho-ß-galactosidase of Staphylococcus aureus,Lactococcus lactis and Lactobacillus casei and 6-phospho-ßglucosidaseB of Escherichia coli build a subfamily inside a greater enzymefamily, named the glycosal hydrolase family 1, which, hi addition,contains nine ß-glycosidases of different origins.Kinetic and immunological evidence is provided in this reportwhich strengthens the relationship of the four 6-phospho-ß-glycosidases.It is shown that the 6-phospho-ß-galactosidases and6-phospho-ß-glucosidase B are able to split aromaticß-galactoside phosphates and ß-glucosidephosphates. The turnover numbers of hydrolysis of substrateswith different epimerization at C-4 of the glycon vary up to15-fold only. Two polydonal antisera, one derived against thenative 6-phospho-ß-galactosidase from S.aureus andthe other derived against the 6-phospho-ß-glucosidaseB, cross-reacted with both enzymes. Peptides of the proteinswere separated by reverse phase HPLC. The cross-reacting peptideswere sequenced and shown to be localized at almost the sameposition in the aligned primary structures of both enzymes.An insertion of nine amino adds near these antigenic domainsis unique for the 6-phospho-ß-glycosidases and missingwithin the sequences of the ß-glycoside-specific membersof the family. The lacG gene of a 6-phospho-ß-galactosidasenegative S.aureus mutant was doned into E.coli and sequenced.In the totally inactive mutant protein only the glycine at position332 was changed to an arginine. This amino acid is part of thesequence insertion near the antigenic domain reacting with bothantisera. These data support the assumption that the regionis of great importance for the function of the enzymes and thatit is possible it determines the specificity of the phosphorylatedform of the substrates. In addition, the 6-phospho-ß-galactosidaseof S.aureus was modified by sitedirected mutagenesis of thecorresponding lacG gene hi order to replace residues Glul60and Glu375, which were suspected of being involved hi the generalacid catalysis of substrate hydrolysis, with glutamine residues.The mutant protein 160EQ retained some catalytic activity whilethe protein 375EQ was totally inactive. Glu375 is the activesite nudeophile of the 6-phospho-ß-galactosidase ofS.aureus. It is located in the sequence motif ENG where Glu358was identified as the catalytkally active nudeophile hi theß-glucosidase of Agrobacterium.     

Evaluation of the protracted stress in the esophageal mucosa of rats

The effect of protracted stress upon the DNA synthesis of the esophageal mucosa of the rat was investigated at various time intervals ranging from one to 56 days. A total of 80 Sprague-Dawley rats were investigated. Lots of 25 rats each were either shock-plunged, subjected to swimming in large basins for two hours or were only transported to the swimming laboratory and used as controls. The remaining 5 rats were non-transported (resting) controls. At the end of the above described procedures, all 80 rats received an intraperitoneal injection of 1 microCi3H-thymidine/gr bodyweight. one hour later the rats were killed. Half of the esophagus was processed for DNA extraction and the other half for autoradiography. When compared to day 0 (resting control rats), the DNA values in experimental animals had increased significantly at day 1, decreased significantly at day 7 in swimming rats and risen once again in both experimental groups at day 14 and more notably at day 28. By 56 days, the values had reached those of day 0. When compared to transported controls at each time interval, both experimental groups had significantly higher DNA values at day 1, significantly lower at day 7 and once again, significantly higher at day 28. Autoradiographic studies of plunged rats showed similar fluctuations in the percentage of labelled basal-parabasal cells in the esophageal mucosa at the various time intervals. The results of this work are similar to those reported previously for the gastric mucosa, the duodenal mucosa and the colonic mucosa of rats subjected to the same stressors.(ABSTRACT TRUNCATED AT 250 WORDS)