Meclofenamate does not reduce chronic hypoxic pulmonary vasoconstriction.

There was no reduction in the pulmonary pressor response to hypoxia following inhibition of prostaglandin synthesis in rats exposed to chronic hypoxia. A fall in left ventricular weight suggested that systemic pressure may have been reduced after inhibition of prostaglandin synthesis in normoxic rats.     

Why the Afshar experiment does not refute complementarity

A modified version of Young's experiment by Shahriar Afshar demonstrates that, prior to what appears to be a “which-way” measurement, an interference pattern exists. Afshar has claimed that this result constitutes a violation of the Principle of Complementarity. This paper discusses the implications of this experiment and considers how Cramer's Transactional Interpretation easily accommodates the result. It is also shown that the Afshar experiment is analogous in key respects to a spin one-half particle prepared as “spin up along x”, subjected to a nondestructive confirmation of that preparation, and post-selected in a specific state of spin along z. The terminology “which-way” or “which-slit” is critiqued; it is argued that this usage by both Afshar and his critics is misleading and has contributed to confusion surrounding the interpretation of the experiment. Nevertheless, it is concluded that Bohr would have had no more problem accounting for the Afshar result than he would in accounting for the aforementioned pre- and post-selection spin experiment, in which the particle's preparation state is confirmed by a nondestructive measurement prior to post-selection. In addition, some new inferences about the interpretation of delayed choice experiments are drawn from the analysis.     

Liminal gastrin does not activate rat stomach histidine decarboxylase

Summary Fasted rats have a low gastric histidine decarboxylase activity. I.v. infusion of heptadecapeptide gastrin for 2 h raised the enzyme activity. Intragastric perfusion with the same dose of gastrin and for the same period of time did not reproduce the effect of circulating gastrin. It is concluded that luminal gastrin, in contrast to circulating gastrin, does not activate rat stomach histidine decarboxylase.This study was supported by the Swedish Medical Research Council (04X-1007, 14X-4144) and by the Albert Påhlsson Foundation.     

Atractyloside does not inhibit the release reaction of blood platelets

Zusammenfassung Atractylosid hat bei menschlichen Blutplättchen keinen Einfluss auf die Aggregation und auf die Freisetzungsreaktion durch ADP und Kollagen in vitro.

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Supported by the Schweizerischer Nationalfonds zur Förderung der wissenschaftlichen Forschung.     

Drosophila melanogaster does not dealkylate [14C]sitosterol

Summary Drosophila melanogaster was unable to dealkylate and convert [¹⁴C]sitosterol to cholesterol and no evidence was found for conversion of [¹⁴C]desmosterol to cholesterol. Therefore,D. melanogaster is incapable of dealkylating and converting C₂₈ and C₂₉ phytosterols to cholesterol.The authors thank O. J. Duncan III, and H. S. Symonds for technical assistance. Mention of a company name or proprietary product does not imply endorsement by the U.S. Department of Agriculture.     

Vasopressin does not stimulate fatty acid synthesis in mouse mammary explants

Summary Fatty acid synthesis in mammary explants from pregnant mice increased after incubation with insulin, cortisol, and prolactin. Replacement of prolactin with vasopressin did not stimulate this activity. Prolactin treated with an anti-vasopressin antiserum had activity similar to untreated prolactin. Thus, stimulation of this lactogenic function by prolactin is not the result of its contamination with vasopressin.Supported by research grant BC-344 from the American Cancer Society.     

Dietary vitamin E does not protect from endotoxin-induced hepatic microvascular dysfunction

Starting from the concept that lipopolysaccharide (LPS)-associated hepatotoxicity involves the action of reactive oxygen species, the present study was conducted to test whether vitamin E, a lipophilic antioxidant, prevents LPS-induced hepatic microvascular dysfunction and liver injury. Fifty-two rats were divided into three groups and fed diets containing 0 (n=16), 75 (n=18) or 8000 mg (n=18) α-tocopherol acetate/kg food for four weeks. At 1 h and 6 h after intravenous LPS-exposure (10 mg/kg E. coli LPS) hepatic microvascular response and liver injury were assessed by the analysis of Kupffer cell phagocytic activity, leukocyte-endothelial cell interaction and nutritive sinusoidal perfusion (intravital fluorescence epi- illumination technique) as well as bile flow, serum liver enzyme activities and tissue histomorphology. In animals fed with 75 mg vitamin E/kg (standard diet), LPS caused hepatic Kupffer cell activation (increased phagocytic activity) and hepatic microvascular leukocyte activation, with stasis in sinusoids and adherence in postsinusoidal venules (1 h) followed by leukocytic infiltration into tissue (6 h) and progredient sinusoidal perfusion failure (6 h). Hepatic microvascular injury was accompanied by reduced bile flow and enhanced liver enzyme release. Vitamin E-enriched diet (8000 mg/kg) and even vitamin E-deficient diet did not significantly affect LPS-induced hepatic microvascular cell activation and perfusion failure. Thus, we conclude, that vitamin E is not effective to protect from endotoxin-induced hepatic microvascular dysfunction. Received 7 November 1996; received after revision 30 December 1996; accepted 20 January 1997     

Calmodulin content does not change following hormone-induced meiosis reinitiation in starfish oocytes

Summary Activator-deficient phosphodiesterase from bovine heart was stimulated by heat-treated dialyzed extracts from starfish oocytes. The same dose-response curve was obtained with extracts from oocytes which had or had not been released from prophase block by 1-methyladenine. Such extracts were shown to contain calmodulin by affinity chromatography on troponin I covalently bound to sepharose and SDS polyacrylamide gel electrophoresis. The results suggest that no change in calmodulin content occurs in starfish oocyte following meiosis reinitiation.     

Thyroid morphology and activity does not respond to ELF electromagnetic field exposures

Summary The hypothesis that the thyroid is the sensitive organ for extremely low frequency electromagnetic field effects was tested. Rats that had been exposed either perinatally or as adults to several intensities of 0.5 Hz magnetic fields displayed no significant alterations in thyroid morphology or circulating hormone measures.Thanks to the technical staff of the Clinical Chemistry Laboratory at Laurentian Hospital.     

Thyrotropin-releasing hormone does not inhibit lysine vasopressin-induced growth hormone secretion in normal men

Summary In order to establish whether thyrotropin-releasing hormone (TRH) inhibits lysine-vasopressin (LVP)-induced growth hormone (GH) release, six normal men were tested with LVP alone or in combination with TRH. LVP strikingly increased serum GH levels; this response was not altered by TRH. These results indicated that in man TRH is not involved in the control of GH secretion in response to LVP.     

Growth-hormone releasing factor does not antagonize somatostatin effects on pancreatic and gastric secretions

Summary The effect of human GRF 44 upon somatostatin-inhibited pancreatic and gastric secretions was studied in rats with chronic fistulas. GRF did not show any antagonist action of somatostatin on these gastro-intestinal organs. GRF alone had a small inhibitory effect on gastric acid output.     

Thyroid morphology and activity does not respond to ELF electromagnetic field exposures.

The hypothesis that the thyroid is the sensitive organ for extremely low freqency electromagnetic field effects was tested. Rats that had been exposed either preinatally or as adults to several intensities of 0.5 Hz magnetic fields displayed no significant alterations in thyroid morphology or circulating hormone measures.     

Growth-hormone releasing factor does not antagonize somatostatin effects on pancreatic and gastric secretions

The effect of human GRF 44 upon somatostatin-inhibited pancreatic and gastric secretions was studied in rats with chronic fistulas. GRF did not show any antagonist action of somatostatin on these gastro-intestinal organs. GRF alone had a small inhibitory effect on gastric acid output.     

Thyrotropin-releasing hormone does not inhibit lysine vasopressin-induced growth hormone secretion in normal men

In order to establish whether thyrotropin-releasing hormone (TRH) inhibits lysine-vasopressin (LVP)-induced growth hormone (GH) release, six normal men were tested with LVP alone or in combination with TRH. LVP strikingly increased serum GH levels; this response was not altered by TRH. These results indicate that in man TRH is not involved in the control of GH secretion in response to LVP.     

Capping of concanavalin A- or ricin-binding sites does not influence phagocytosis in polymorphonuclear leukocytes

Summary Rabbit polymorphonuclear leukocytes (PMNs) were capped with territin-conjugated concanavalin A or ricin, and then allowed to phagocytose yeast cells. Phagocytic activity and lectin distribution were determined by ultrastructural morphometry. Capped PMNs were found to phagocytose as efficiently as control PMNs, and always to ingest the particles with a lectin-free portion of their plasma membrane. This clearly indicates that concanavalin A- and ricin-binding sites of the PMN membrane are not involved in the recognition and phagocytosis of yeast particles.     

RH-5849, a nonsteroidal ecdysone agonist,does not mimic makisterone-A inDysdercus koenigii

The response of final instar nymphs ofDysdercus koenigii to topical application of the non-steroidal ecdysone agonist, RH-5849, was dose dependent. The candidate compound produced mortality even at moderate doses, but precocious adult development was not observed. Similar results were obtained after oral administration or injection. Conversely, injections of makisterone-A (the principal moulting hormone ofDysdercus) into 5th instar nymphs resulted in precocious adult development within 4 days. We conclude that RH-5849 does not mimic makisterone-A, as is the case with ecdysone, and that toxicity is mediated instead through non-endocrine targets in this insect species.     

Chronic exercise does not alter the chronotropic response of isolated rat atria to catecholamines

Summary Atria isolated from rats after 7 weeks of exercise training beat at a slower rate than did atria from sedentary controls. There is no significant difference between the chronotropic responses of the 2 groups to epinephrine or morepinephrine.This study was supported in part by a grant from the Genesee Valley Heart Association.     

Treatment of mice with monosodium glutamate does not inhibit a subsequent response to gold thioglucose

Neonatal mice were injected with monosodium glutamate (MSG) followed 10 days later by treatment with gold thioglucose (GTG). Weight gain, food consumption and body lipid determinations were made. Results indicated that pretreatment with MSG does not block subsequent response to GTG and the resulting changes are similar to those induced by GTG alone.     

Circadian pacemaker does not arrest in deep hibernation. Evidence for desynchronization from the light cycle

A freerunning rhythm of locomotor activity was observed between hibernation bouts in Turkish hamsters (mesocricetus brandti) kept in 10L:14D light-dark cycles at 10 +/- 1 degree C. The data further indicate an influence of natural hypothermia upon the circadian system and its ability to entrain to light-dark cycles.