摘要:

Abstract:Adult male rats were treated intraperitoneally with chloroquine (5 mg/kg/day) for 9 days. A reduction in the fasting plasma glucose level by 17.6% and ascorbic acid by 45% were discernable. The treatment caused significant increase in liver lactate dehydrogenase and glucose‐6‐phosphate dehydrogenase activities and reduced the activity of succinate dehydrogenase enzyme. Chloroquine also caused significant reductions in the contents of reduced glutathione and ascorbic acid in the brain and erythrocytes with a significant increase in lipid peroxidat

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00538.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:The mutagenicity of senna glycosides and extracts of senna folium and senna fructus was investigated in theSalmonella typhimuriumreversion assay. Senna glycosides were inactive in all strains, except for a slight, but significant increase in mutant frequency in TA102 in the absence and presence of liver microsomes. Extracts of senna fructus and senna folium demonstrated weak activity in TA97a, TA100 and TA102 in the presence of liver microsomes, and in TA97a and TA102 in the absence of liver microsomes. A strong increase in mutant frequency (3‐ to 5‐fold above background frequency) was observed with all extracts in TA98 in the presence of liver microsomes. This activity increased further following enzymatic hydrolysis with hesperidinase of extracts of senna fructus from one source, and could be correlated to the release of the flavonol aglycones kaempferol and quercetin. The weak or lacking activity of anthraquinone aglycones in the tested strains ofSalmonella typhimuriumindicates that mutagenicity can not be attributed solely to the anthraquinone content of these plant materials. The chemical nature of other mutagenic components has not been elucida

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00539.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:Effect of cocaine on morphine‐induced analgesia and the accompanying respiratory depression, bradycardia and hypolocomotion/sedation was studied in rats. Cardiovascular and respiratory effects were studied under pentobarbitone‐induced anaesthesia. Cocaine enhanced morphine‐induced analgesia in the formalin test, hot plate test and heatinduced tail withdrawal test in intact rats. However, in spinal rats a similar combination of cocaine with morphine did not produce increased latencies in the tail withdrawal test. Of the three analgesic tests used, the formalin test was the most sensitive to the enhancement, as well as to the effects of morphine or cocaine alone. Morphine at the dose of 6 mg/kg produced complete analgesia in the formalin test, significant hypolocomotion/sedation, significant bradycardia and significant decrease in the respiratory rate. At an equianalgesic dose (complete analgesia in the formalin test) of morphine (3 mg/kg)‐cocaine (5 mg/kg)‐combination no significant changes in heart rate, respiratory rate or locomotion(/alertness) were observed. Changes in skin blood flow determined by the laser Doppler flow method were not significant in any of the experimental conditions. The results indicate that cocaine enhances morphine‐induced analgesia, mainly due to supraspinal mechanisms. In contrast, the morphine‐induced bradypnoea, bradycardia and hypolocomotion/sedation are attenuat

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00540.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:Isometric recordings of mechanical activity in muscle strips from rat and human detrusor were performed and the effect of μ‐ and δ‐opioid receptor stimulation and blockade on detrusor contraction induced by electrical field stimulation was tested. Stimulation of the opioid μ‐receptor with morphine (10‐13‐10‐4M) and DAGO (10‐13‐10‐6M) had no significant effect on electrical field stimulation except at one concentration of morphine (10‐6M). Naloxone (10‐10‐10‐5M) caused a significant facilitation of the electrical field stimulation‐induced contraction, which was counteracted by morphine (10‐8M) and the δ‐agonist DPDPE (10‐8M) in both rat and human detrusor. Addition of atropine (10‐6M) or hexamethonium chloride (10‐6M) or spantide (10‐6M) did not alter the facilitating effect of naloxone in the rat detrusor. Hexamethonium (10‐5M) decreased the facilitating effect of naloxone on electrical field stimulationinduced contractions in the human detrusor, indicating involvement of ganglionic mechanisms. In human detrusor about 15% of the contractile response was found to be atropine‐resistant (10‐6M) and one third of this was found to be resistant to tetrodotoxin (1.5 × 10‐6M). The atropine resistant‐response in human detrusor was facilitated by naloxone to the same extent as the atropine‐sensitive part. Adrenergic blockade per se, achieved with phentolamine mesylate (10‐6M) and propranolol (10‐6M), caused a significant facilitation of the electrical field stimulation‐induced contraction in the rat detrusor but did not affect the facilitating effect of naloxone (10‐13‐10‐5M). Addition of the δ‐agonist DPDPE (10‐13‐10‐5M) did not significantly change the detrusor response to electrical field stimulation in rat detrusor, but the δ‐antagonist naltrindole (10‐13‐10‐5M) caused a significant facilitation at the highest concentration. In human detrusor, DPDPE 10‐8M significantly reduced the response induced by electrical field stimulation. Conclusion: Blockade of the opioid receptors with naloxone facilitates the detrusor contraction elicited by electrical field stimulation. The existence of a tonic, inhibitory action on the detruso

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00541.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:Wistar rats were treated with gentamicin in single (80 mg/kg) or repeated doses (7 × 40 mg/kg) subcutaneously. Total protein as well as excretion of essential metals (Cu, Zn) with the urine were determined 24 hr after 1, 3 and 7 dosages as well as 3 and 7 days after the termination of administration. At the same time kidneys were examined histopathologically by light microscopy. Simultaneously, Cu, Zn and metallothionein levels in kidneys and liver were determined. Rats receiving gentamicin demonstrated progressive renal proximal tubular necrosis at the end of 7 days administration. At the same time elevated copper and zinc levels were observed in urine. These essential metals seem to be an indicator of gentamicin nephrotoxicity

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00542.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:Effects of tri‐n‐butyltin (TBT) on mouse thymocytes were examined using a flow‐cytometer and fluorescent dyes for membrane potential and intracellular Ca2+([Ca2+]i). TBT at concentrations from 1 × 10‐7M to 3 × 10‐7M caused hyperpolarization in thymocytes during 30 min. after drug application in a time‐ and dose‐dependent manner. Further increase in TBT concentration (to 1 × 10‐6M) made hyperpolarization of thymocytes more profound within 5 min. after application, thereafter gradually depolarized them during the next 25 min. TBT at 3 × 10‐8M or more (up to 1 × 10‐6M) increased the [Ca2+]iof thymocytes. After reaching maximum [Ca2+]iat the various TBT concentrations used within 5 min. after drug application, the [Ca2+]islightly decreased in a time‐dependent manner. Effects of TBT on membrane potential and the [Ca2+]iwere greatly reduced under nominal external Ca2+‐free condition. Results suggest that TBT can promote Ca2+‐influx to thymocytes, resulting in hyperpolarization by activation of Ca2+‐dependent K+current. The increase in [Ca2+]iby TBT may be related to it

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00543.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:Chloral hydrate is used as a sedative in infants requiring ventilatory support. The metabolites, trichloroethanol and trichloroacetic acid, accumulate in the serum and are protein bound. The possibility that these chemicals might compete with bilirubin for albumin binding was tested using the peroxidase method and a dialysis rate method. Chloral hydrate and trichloroethanol had no effect on bilirubin‐albumin binding. Trichloroacetic acid affects bilirubin‐albumin binding but to a degree that would be dangerous only in infants with an unusual accumulation of this metabol

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00544.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:By use of a methylmethacrylate (MMA) Dräger tube and bellow bump, the breathing zone concentrations of MMA monomer were measured for the operating surgeon during cementation of the components of hip and knee joint prostheses. The highest recordings (50–100 p.p.m.) were encountered during cementation of the acetabular cups with conventional polymethylmethacrylate cement. Such exposure could be eliminated by the use of personal protection equipment, local punctual field suction or change to a MMA/n‐decylmethacrylate/isobornylmethacrylate bone ce

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00545.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:The burning and painful effect in nose and eyes, termed sensory irritation, of methyl ethyl ketone varpours was investigated in a mouse bioassay. Sensory irritation is mediated via the trigeminal nerves and results in a reflexively induced decrease in respiratory rate in mice. Methyl ethyl ketone was used as a model substance for ketones. At the lower exposure concentrations a partial fading (desensitization) of the response was seen. Little desensitization was seen at higher concentrations. n‐Propanol, a model substance for alcohols, desensitized the receptor at all exposure levels. Preexposure to propanol did not influence the response at high methylethyl ketone concentrations. This suggests that the two substances bind to different receptive sites with different properties, if the ketone response is due to a high exposure concentration. A decrease in tidal volume was also mediated from the upper respiratory tract. The tidal volume effect is mediated by nerves different from those mediating the frequency response, as the time‐response relationship, the desensitization pattern, the maximum response and the apparent dissociation constants were different for the two types of effect. Neither the location nor the perceived response related to the volume response is kn

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00546.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

Abstract:The effect of cadmium (Cd) as CdCl2on some placental enzyme activities were studied after explants had been incubated with the salt for 6 or 24 hr. The results indicated that, for both incubation periods, Cd at low doses had a stimulatory effect on aryl hydrocarbon hydroxylase (AHH) (a phase I enzyme) and on quinone reductase and catecholamine‐O‐methyltransferase (COMT) (both phase II enzymes). This effect was dose‐ and time‐dependent. Only the activities of AHH and COMT showed a biphasic response, (i.e., increases at the lower dose levels and decreases with the higher ones), whereas that of quinone reductase continually increased with all the dose levels of the metal administered. Glucose‐6‐phosphate dehydrogenase (G‐6‐PD) activity was found to be inhibited at all the dose levels of Cd tested, the effect also being time‐ and dose‐dependent. In conclusion, it appears that the use of placental explants can serve as a valuable means for studying the toxic effects of certain xenobiotics, as reflected in the activity of variou

ISSN:0901-9928    

DOI:10.1111/j.1600-0773.1992.tb00547.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY