Behavioral taste responses of developmentally NaCl-restricted rats to various concentrations of NaCl.

The behavioral taste responses of developmentally NaCl-restricted rats were examined with a brief-exposure taste test. Neurophysiological and morphological alterations have been reported in rats whose dietary sodium is restricted during pre- and postnatal development, there exists little data discerning their behavioral response to tastants. Control and developmentally NaCl-restricted rats were maintained on a low-NaCl diet and trained to lick from individually presented sipper tubes. Each subject received 4 days of testing on various NaCl concentrations. Results indicate that developmentally NaCl-restricted rats have dramatically increased lick rates to NaCl solutions. These responses are likely due to some combination of factors including (a) numbers and type of active chorda tympani fibers, (b) compensatory responses to NaCl-solutions from other nerves of the oral cavity, and (c) increased sensitivity of central taste systems to NaCl. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Induction of anovulatory sterility by neonatal treatment with 5 beta-dihydrotestosterone in female rats

Wistar female rats were injected with testosterone (T) or 5 beta-dihydrotestosterone (5 beta-DHT) for the first 5 days of life. Neonatal treatment with 1 mg of T resulted in anovulatory persistent oestrous syndrome in 100% of the animals. In the females injected with 1 mg of 5 beta-DHT, 74% of the treated rats became sterile at 120 days of age. In addition, 0.5 mg 5 beta-DHT was also effective in inducing anovulatory persistent oestrus; the incidence of sterility was 10 and 80% at 60 and 120 days of age, respectively. When daily dose of 5 beta-DHT was reduced to 0.1 mg, however, only 33% of the rats resulted in sterility. These results suggest that the free form of T and non-aromatizable androgen, 5 beta-DHT, can permanently suppress the development of female type of neuroendocrine regulation. The possible participation of the process other than the central aromatization in androgenization will be discussed.     

Environmentally assisted cracking of two-phase Fe-Mn-Al alloys in NaCl solution

Three two-phase Fe-Mn-Al alloys with nominal compositions, Fe-24Mn-9Al, Fe-27Mn-9Al-3Cr,. and Fe-27Mn-9Al-6Cr, were prepared in the solution-treated and cold-rolled conditions. The fractions of ferrite in the solution-treated condition were controlled at 46 to 60 pct, mainly by adjusting the carbon content and the relative amounts of Mn and Al. The ferrite fractions were reduced to 30 to 37 pct after 75 pct deformation by cold-rolling. Specimens were tensile tested at open circuit in aerated 3.5 pct NaCl solution at slow strain rates ranging from 4 × 10^-7 to 4 × 10^-5 s^-1 at room temperature. All of the alloys were quite susceptible to environmentally assisted cracking (EAC). The deformed specimens showed less susceptibility, presumably because the plasticity was already too limited. The EAC appeared to occur at or after the onset of plastic deformation. In this alloy system, the ferritic phase was less resistant to EAC than the austenitic phase, in contrast to the Fe-Cr-Ni stainless steels. The crack propagated preferentially through the ferrite grains or along the ferrite/austenite grain boundaries. The addition of up to 6 pct Cr did not improve the EAC resistance. Formerly Graduate Student, Department of Materials Science and Engineering, National Tsing Hua University     

碳钢在NaCl溶液中初始腐蚀行为的探讨

采用电化学极化与金相显微镜原位观察相结合的方法,对Q235钢在3%NaCl溶液中腐蚀的初始行为进行了研究。借助原子力显微镜对初始腐蚀的试样观察分析,发现试样在-900 mV(vs SCE)就出现了点蚀,点蚀优先在晶界附近的铁素体上生成。蚀坑长大后,优先沿轧制方向发展,而形成腐蚀沟槽。钢中夹杂没有发生活性溶解,导电性夹杂物作为阴极仅对腐蚀过程起促进作用。     

Analgesic effect of vaginal stimulation in rats: modulation by graded stimulus intensity and hormones

Regulation of nitrogen fixation by ammonium and glutamate was examined in Rhizobium sp. 32H1 growing in defined liquid media. Whereas nitrogenase synthesis in Klebsiella pneunoniae is normally completely repressed during growth on NH4+, nitrogenase activity was detected in cultures of Rhizobium sp. grown with excess NH4+. However, an "ammonium effect" on activity was invariably observed in cultures grown on NH4+ as sole nitrogen source; the nitrogenase activity was, depending on conditions, 14 to 36% of that of comparable glutamate-grown cultures. Glutamate inhibited utilization of exogenous NH4+ and, in one of two procedures described, glutamate partially alleviated the ammonium effect on nitrogenase activity. NH4+, apparently produced from N2, was excreted into the culture medium when growth was initiated on glutamate, but not when NH4+ was thesole source of fixed nitrogen for growth. These findings are discussed in relation to nitrogen fixation by Rhizobium bacteroids.     

Pitting corrosion behavior of cerium treated HSLA steel induced by sulfide inclusions in 3.5 wt% NaCl solution

Pitting corrosion behavior of Ce treated HSLA steels induced by sulfide inclusions in 3.5 wt% NaCl solution was investigated with potentiodynamic polarization and immersion corrosion test.The results show that Ce added steels exhibit better pitting corrosion resistance with lower corrosion current density and bigger pitting potential compared with steel without Ce,which is mainly attributed to optimized characteristics of spherical Ce-oxysulfide inclusions with less number density,smaller average size and lower pitting corrosion susceptibility.The spherical Ce₂O₂ S inclusions precipitated on the surface of CeAlO₃ inclusions in the Ce added steels induce pits with bigger opening mouth and shallow depth,reducing their tendency of extension to go deeper due to occlusion corrosion battery in the pitting holes.Furthermore,corrosion inhibitor Ce(OH)₃ generated by Ce₂O₂ S hydration can weaken electrochemical corrosion of the matrix micro-region around the pits.To avoid harmful bigger inclusions,Ce content in steels should be regulated within reasonable range,0.015 wt% Ce in present steels effectively modified inclusions to acquire the best pitting corrosion resistance of the steels.     

Chronic alcoholization in rats by free-choice ingestion of a hydroalcoholic solution

The present work addresses a schedule designed to render rats alcoholic by offering them free access to a 20% (v/v) ethanol solution over 6 weeks. A solid diet and water (for controls) were fully available ad lib. in the animals' cages. The treatment was observed to achieve some effects suitable for the chronic alcoholization of rats: (1) Ethanol furnished the 36% of the calories of the diet of ethanol-treated rats; (2) The daily ethanol intake achieved was 12.05 +/- 1.18 g ethanol/kg weight; (3) The morning blood ethanol level was 0.45 g/litre; (4) Ethanol-treated rats deprived of ethanol showed several withdrawal symptoms. These results agree with those obtained by standard liquid diets, suggesting that the current protocol can be used to achieve a status of chronic alcoholization in rats.     

Arteriovenous differences in plasma concentrations of catechols in rats with neuropathic pain

BACKGROUND: Alterations in cutaneous temperature, sweating, and cutaneous blood flow in patients with pain states, such as reflex sympathetic dystrophy and causalgia, have been interpreted as evidence for exaggerated sympathetic outflow. It was determined whether pain behavior in a rat model of sympathetically maintained pain is associated with alterations in regional sympathoneural function. METHODS: Peripheral neuropathy was induced in 29 Sprague-Dawley rats by ligation of the left L5 and L6 spinal nerves. Sixteen other rats had sham surgery (nerve exposure without ligation). Animals were tested for behavioral signs of allodynia (decreased paw withdrawal thresholds to mechanical stimuli) at 2 and 4 weeks after the surgery. Arterial and iliac venous blood samples (left, affected; right, control) were obtained at 2 weeks (NP2, n = 14) and 4 weeks (NP4, n = 15) after neuropathic or sham (n = 8 at 2 and 4 weeks) surgery. Plasma concentrations of dihydroxyphenylalanine, dihydroxyphenylacetic acid, dopamine, norepinephrine, and the intraneuronal norepinephrine metabolite, 3,4-dihydroxyphenylglycol, were analyzed in arterial and left and right iliac venous samples. RESULTS: A decrease in paw withdrawal threshold was observed in neuropathic (NP2 and NP4) but not sham-operated rats. Affected and control limbs did not differ in arteriovenous differences in concentrations of dihydroxyphenylalanine, dihydroxyphenylacetic acid, dopamine, or 3,4-dihydroxyphenylglycol. No differences were observed between sham-operated and neuropathic animals in these arteriovenous increments. In contrast, affected limbs of NP2 rats had a reduced arteriovenous increment in norepinephrine concentrations, compared to that in the control side (P < 0.05). CONCLUSIONS: No neurochemical evidence of sympathetic hyperactivity is observed in the rat model of neuropathic pain; if anything, norepinephrine release is decreased in the affected limb. Autonomic disturbances in neuropathic pain are therefore more likely the result of receptor supersensitivity than increased local sympathoneural traffic.     

Effect of graded doses of cortisol on total body calcium in rats

Male rats with an average body weight of 250 g were injected (sc) daily for 4 wk with 0.05, 0.20, 0.75, or 3.00 mg of cortisol acetate. Intact and adrenalectomized control animals were injected daily with 0.1 ml of vehicle (corn oil). Total body calcium (TBCa) was measured weekly in each rat by in vivo neutron activation analysis. The gain is body weight of rats treated with 0.75 mg cortisol was significantly less than controls, and the animals treated with 3.00 mg cortisol lost weight. In spite of these differences in body weight, the TBCa of all rats increased to an equal degree from an average of 1.93 g to 2.81 g in 4 wk. In addition, there were no significant differences in tibial ash calcium. However, calcium (mg) per unit length (mm) of tibia was increased in rats treated with the higher doses of cortisol; thus bone density was increased. These results demonstrate that the TBCa increases even when rats are subjected to cortisol. This is explained in part by the normal rate of intestinal calcium absorption in cortisol-treated rats.     

Induction of gastric lesions and hypoglycemic response by food deprivation in streptozotocin-diabetic rats

Overnight fasting causes hemorrhagic lesions in the stomach of streptozotocin (STZ)-induced diabetic rats, but the pathogenetic mechanism remains unknown. The present study was performed to investigate the pathogenesis of such lesions developed in STZ-diabetic rats after starvation, mainly in relation to blood glucose changes. A single injection of STZ (70 mg/kg, intraperitoneally) induced hyperglycemic conditions one week after the administration, and high blood glucose levels (BGL: > 350 mg%) remained up to three weeks later. The STZ-diabetic rats developed gastric lesions with the marked reduction of BGL after 18 hr of fasting, depending upon the duration of diabetes; the lesion score and delta BGL reduction in the 3-week-old STZ rats were 32.0 +/- 7.8 mm and > 250 mg/100 ml, respectively. Acid secretion in the pylorus-ligated rats was not significantly changed in the STZ-induced diabetic conditions for the initial two weeks but slightly decreased at three weeks when compared with normal rats. Fasting of normal rats for 18 hr did not cause either BGL reduction or any lesion in the stomach. In the 3-week-old STZ animals, the severity of gastric lesions increased with the duration of fasting (4-18 hr) and was again closely associated with the degree of delta BGL reduction. These lesions induced by 18 hr of starvation in 3-week-old STZ rats were significantly inhibited by pretreatment with insulin (4 units/rat/day) for the last one week to maintain BGL within normal ranges or by intravenous infusion of 25% glucose during fasting period. Both of these treatments significantly prevented BGL reduction in response to fasting.(ABSTRACT TRUNCATED AT 250 WORDS)     

Haloperidol and reduced haloperidol plasma concentrations after a loading dose regimen with haloperidol decanoate

1. Haloperidol and reduced haloperidol plasma levels were measured in schizophrenic patients who received both oral (10 mg, N=16 and 20 mg, N=4) and depot haloperidol treatment 2. Patients were of Asian ethnicity and were safely and effectively converted from oral to depot therapy using a loading dose regimen using a 100 mg weekly injection interval for 4 weeks, biweekly for one month and then monthly. 3. Significant correlations were found for plasma haloperidol and reduced haloperidol levels and reduced haloperidol/haloperidol ratios between oral and depot therapy in these non-smoking patients. 4. A loading dose regimen is needed due to the long elimination half-life of decanoate of 26 days otherwise steady-state condition will not occur until 34 months of therapy. 5. Patients were maintained on monthly depot treatment for 40 weeks after the loading dose regimen and only one patient relapsed during treatment despite dosage increases. 6. The formation of reduced haloperidol remained consistent for oral and depot haloperidol treatment.     

Nonpulsatile arterial waveforms: observations during graded testicular torsion in rats

RATIONALE AND OBJECTIVES: We tested whether testicular torsion could completely damp distal arterial pulsatility, resulting in venous-appearing arterial waveforms. METHODS: Progressively increasing testicular torsion was unilaterally produced in five rats. Doppler waveforms of the testicular artery distal to the torsion were obtained as soon as possible after each level of torsion until a complete absence of pulsatility was noted. RESULTS: One animal was not studied further after the first 180 degrees of torsion occluded flow. In three of the remaining four animals, the testicular artery resistive index (RI) at baseline (0.51, 0.58, 0.64) was within the range of the normal human intratesticular RI and decreased with increasing torsion, culminating in nonpulsatile, venous-appearing waveforms at high degrees of torsion. CONCLUSIONS: Testicular torsion can completely damp arterial pulsatility, resulting in nonpulsatile, venous-appearing arterial Doppler waveforms.     

Corrosion behavior of zirconium diboride-based ceramics and electrospark coatings in 3% NaCl solution

The paper examines the corrosion behavior of AlN-ZrB₂, AlN-TiN, and ZrB₂-LaB₆ composite materials and associated electrospark coatings based on aluminum alloy AL9 in 3% NaCl solution. It is shown that the electrochemical corrosion resistance of composites is close to that of titanium nitride. __________ Translated from Poroshkovaya Metallurgiya, Vol. 46, No. 1–2(453), pp. 54–57, 2007.     

Induction of long-term depression (with anxiety and fear components) by immunization of rats against pargyline

The active immunization of albino rats against pargyline (a MAO B inhibitor) induced the formation of antibody to pargyline and results in deep depressive changes and fear. These changes were observed within 6 weeks after the first immunization. Therefore, it opens the possibility to model depression long by exerting the minimum influences. There was also a long-term modulation of craving for alcohol.     

Development of the enhanced neural response to NaCl in Fischer 344 rats

Duplications of the esophagus or stomach alone are infrequent, and complete foregut duplication has only rarely been described. Most combined esophagogastric duplications present within the first year of life, and if communication with the normal alimentary tract does occur, it does so only either above or below the diaphragm. This report illustrates a case of continuous duplication of the esophagus and stomach with communication to the normal alimentary tract at both proximal and distal ends. Operative management and a review of the literature and embryology are described.