摘要:

For 8 weeks 10 male weanling Sprague–Dawley rats were fed a semisynthetic diet containing by weight either 20% corn oil or rapeseed oils containing different amounts of erucic acid (Brassica napusvar. Zephyr, 0.6%;B.napusvar. Oro, 1.8%;B.campestrisvar. Span, 4.8%; orB.campestrisvar. Echo and Arlo,i.e., regular rapeseed oil, 23.6%). At 4–5 weeks after the experiment began, rats receiving the diets containing rapeseed oil showed evidence of alopecia and developed scaly, hemorrhagic, and necrotic tails, as well as scaliness of the feet, similar to the lesions described in essential fatty acid (EFA) deficiency. This condition became most severe between 5 and 8 weeks and had disappeared by 14 weeks. Fatty acid analysis of the diets and tissues of the animals did not reveal any evidence of EFA deficiency. It is suggested that these symptoms observed might be related to a possible inhibition of prostaglandin biosynthesis in rats fed rapeseed oils.

ISSN:0008-4212    

DOI:10.1139/y76-001

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Marking of the largest (F1) and the second largest (F2) follicles of the ovaries of the sheep with India ink has allowed us to observe the fate of these follicles after different treatments.All the F1and F2follicles of the controls marked on the 10th day of the cycle became atretic, but when the marking was done on the 14th day, only the F1(of the marked follicles) ovulated. Destruction of the F1with or without removal of the corpora lutea allowed some of the F2to ovulate, whereas only removal of the corpora lutea decreased the number of F1ovulating. It thus appears that the fate of the F1is related to the time of the cycle and that the F1could have an inhibitory effect on the ovulation of the F2. Removal of the corpora lutea also induced the development of several cystic follicles and decreased the total ovulation rate.

ISSN:0008-4212    

DOI:10.1139/y76-002

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Guinea-pig ileum myenteric plexus–longitudinal muscle preparation was superfused with [3H]choline for 15 min either without being stimulated or during field stimulation at 0.1 or 16 Hz; the preparation was then either removed immediately or after 75- or 135-min superfusion with hemicholinium-3 (HC-3) and the total acetylcholine (ACh) and [3H]ACh contents were determined. For measuring the release of [3H]ACh the preparation was stimulated for 60 min the second time at 0.1 or 16 Hz in the presence of hemicholinium. Exposure to [3H]choline without stimulation resulted in the formation of [3H]ACh which decreased without further stimulation in the presence of HC-3 at the same rate as did total ACh. Labelling during 0.1-Hz stimulation resulted in [3H]ACh stores which were maintained in the first 75 min but decreased thereafter. Labelling during stimulation at 16 Hz produced the largest and best maintained [3H]ACh content. Following labelling during 0.1-Hz stimulation, more label could be released than following labelling in the absence of stimulation. Labelling during 16-Hz stimulation did not increase any further the pool of [3H]Ch accessible to release by 0-Hz stimulation, but caused a 2.5 times increase in the pool from which 16-Hz stimulation released [3H]ACH. These results suggest that two populations of cholinergic neurons exist in the myenteric plexus, one activated only by high frequency stimulation, the other by both high and low frequency stimulation.

ISSN:0008-4212    

DOI:10.1139/y76-003

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

In rats four daily skin applications of a 30% solution of a polychlorinated biphenyl (PCB) mixture in mineral oil or of a microscope immersion oil, containing 34% PCB, led to increases in liver weight, protein concentration of the 10 000 × gsupernatant fluid of liver homogenates and thein vitroglucuronidation of thyroxine (T4) by the supernatant fluid, whether related to liver weight or to protein concentration in the reaction mixture. Similar effects occurred after feeding 250 ppm (mg/kg) of PCB in either Purina chow or a low-iodine diet for 11 days. It is concluded that increased hepatic T4glucuronidation contributes to the enhanced biliary excretion of T4previously observed in PCB-treated rats.

ISSN:0008-4212    

DOI:10.1139/y76-004

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The behaviour of desialylated human and chicken acid α1-glycoproteins is reported in chickens. Although desialylation resulted in accelerated disappearance rates from the plasma of both proteins, nevertheless the asialoproteins were eliminated much more slowly than expected on the basis of earlier observations in mammals. Analysis of tissue radioactivities, including kidney, liver, lung and spleen, failed to demonstrate any accumulation of the labeled asialoproteins in the liver, which is contrary to the situation in mammals. The main pathway for the elimination of desialylated human acid α1-glycoprotein in the chicken is via the kidney (tubular catabolism and/or urinary excretion). The clearance of desialylated chicken acid α1-glycoprotein is more complex as it involves the kidney as well as the reticuloendothelial system.These findings indicate that, unlike mammals, chickens do not possess a hepatic plasma membrane receptor for asialoglycoproteins. This raises the possibility that the presence or absence of this specific receptor may constitute a fundamental biological difference between mammals and birds.

ISSN:0008-4212    

DOI:10.1139/y76-005

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

1. The effects of a series of aliphatic alcohols (methanol to octanol) on membrane proteins of erythrocytes were studied by monitoring the fluorescence of a dye (1-anilino-8-naphthalenesulfonic acid (ANS)) that adsorbs to erythrocyte ghost membranes. Low concentrations of all the alcohols reduced the ANS fluorescence of the membrane–ANS suspensions; lent to those which protect against hypotonic hemolysis on intact erythrocytes; higher concentrations markedly increased the fluorescence. Ethanol and methanol decreased ANS fluorescence at all concentrations.2. Lytic concentrations of saponin did not increase ANS fluorescence and did not modify the membrane action of the alcohols.3. None of these effects were observed in liposomes prepared from lipid extracts of the erythrocyte membrane.4. Since the apparent dissociation constant for the ANS–membrane interaction was unchanged in the presence of the alcohols, it was assumed that the fluorescence changes reflected alterations in the number of ANS binding sites. One conclusion is that low anesthetic concentration of the alcohols alter the conformation of membrane proteins, as indicated by the decreased number of ANS binding sites.

ISSN:0008-4212    

DOI:10.1139/y76-006

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Furosemide, administered intravenously (50 mg/kg) to guinea pigs, caused an increase in the sodium concentration and a decrease in the potassium concentration of endolymph, and a fall in the endolymphatic potential. The furosemide-induced electrolyte changes were prevented by pretreatment of five guinea pigs with propranolol given intravenously (2 mg/kg). The fall in the endolymphatic potential was not prevented by propranolol. Local administration of furosemide to the perilymphatic or endolymphatic space caused a fall in the endolymphatic potential, but had no effect upon the concentrations of sodium and potassium of endolymph. These studies provide additional information suggesting the mutual independence of the endolymphatic potential and sodium and potassium concentration gradients.

ISSN:0008-4212    

DOI:10.1139/y76-007

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

To examine the role of changes in calcium transport by subcellular particles in the pathogenesis of contractile failure due to oxygen lack, both mitochondrial and microsomal fractions were obtained from the isolated hypoxic rat hearts and their calcium binding and uptake abilities were determined by the Millipore filtration technique. The contractile force decreased by about 40, 60 and 70% of the control within 5, 10 and 30 min respectively, of perfusing the heart with hypoxic medium containing glucose. In hearts perfused for 10 min with hypoxic medium containing glucose, calcium binding and uptake by the microsomal fraction decreased significantly. However, mitochondrial calcium binding, but not uptake, decreased significantly on perfusing the hearts with hypoxic medium containing glucose for 20 to 30 min when the microsomal calcium transport was markedly depressed. Reduction in contractile force, calcium binding and uptake by the microsomal fraction as well as calcium binding by mitochondria of hearts made hypoxic for 30 min recovered towards normal upon reperfusion with control medium for 15 min. On the other hand, omitting glucose from the hypoxic medium significantly decreased calcium binding by mitochondrial and microsomal fractions within 10 min of perfusion in comparison to the control and accelerated the effects of hypoxia upon contractile force and microsomal calcium uptake. In contrast to the hypoxic hearts, the mitochondrial calcium uptake decreased significantly and the magnitude of depression in the microsomal calcium binding was appreciably greater in hearts made to fail to a comparable degree upon perfusion with substrate-free medium. The observed defects in calcium transporting properties of microsomal and mitochondrial membranes appear secondary to the contractile failure in hypoxic hearts.

ISSN:0008-4212    

DOI:10.1139/y76-008

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Chronic experiments were carried out on three groups of rats to evaluate tissue and electrolyte effects of a mineralocorticoid blocker canrenoate potassium (SC-14266) during DOCA-induced hypokalemic metabolic alkalosis. Group I animals received DOCA alone, group II received DOCA plus canrenoate, while group III received canrenoate alone. The daily dose ratio (per kilogram of body weight) was 180 mg canrenoate – 0.45 mg DOCA. All animals ate a synthetic diet and drank 0.15 NNaHCO3Group II animals demonstrated a lesser degree of metabolic alkalosis and a higher muscle potassium content when compared with group I rats. The most conspicuous histological abnormality was myocardial necrosis, the degree and extent of which was impressively reduced by the blocking agent.

ISSN:0008-4212    

DOI:10.1139/y76-009

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Single relay (to thalamus) and nonrelay neurones that responded to innocuous and/or noxious oral–facial stimuli were located in trigeminal brain stem nuclei oralis and caudalis. The responses of the cells and the digastric muscle to these stimuli were tested with conditioning stimulation of the periaqueductal gray matter (PGM) and somatosensory cerebral cortex in cats. A greater suppression of nociceptive responses with PGM stimulation was noted, and this effect may contribute to the profound analgesic action that has been reported to occur with PGM stimulation.

ISSN:0008-4212    

DOI:10.1139/y76-010

出版商:NRC Research Press    

年代:1976

数据来源: NRC