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21.
Nonocclusive main pulmonary arterial distension produces peripheral pulmonary hypertension. The mechanism of this response is unknown. The effects of total spinal anesthesia on the response were studied in halothane-anesthetized dogs. Before total spinal anesthesia, main pulmonary arterial balloon inflation increased pulmonary arterial pressure and resistance without affecting systemic hemodynamic variables. Both right and left pulmonary arterial pressures were monitored to exclude unilateral obstruction with main pulmonary arterial balloon inflation. Total spinal anesthesia decreased cardiac output and systemic arterial pressures. After total spinal anesthesia, main pulmonary arterial distension still increased pulmonary arterial pressure and resistance. Right atrial pacing, discontinuation of halothane anesthesia, and norepinephrine infusion during total spinal anesthesia partially reversed the hemodynamic changes caused by total spinal anesthesia. The percent increase in pulmonary vascular resistance due to main pulmonary arterial distension was similar before total spinal anesthesia and during all experimental conditions during total spinal anesthesia. The pulmonary hypertensive response is therefore not dependent on central synaptic connections. 相似文献
22.
Foscarnet sodium (trisodium phosphonoformate hexahydrate) has been shown to inhibit herpes simplex virus (HSV) in vitro and to be efficacious for topical treatment of experimental HSV infection in animals. To assess its clinical efficacy in the treatment of recurrent orolabial herpes a multicentre collaborative, double-blind, placebo-controlled trial was conducted. The study patients were randomly assigned to receive either 3% foscarnet cream (78 patients) or placebo (cream vehicle) (75 patients) and were asked to start treatment at the earliest indication of a recurrence. Efficacy was evaluated in 143 patients (74 in the foscarnet group and 69 in the placebo group). There was no significant difference in time to healing or duration of virus shedding between the two groups. However, in the subgroup of patients who started treatment before vesicles appeared, the duration of virus shedding was shorter in the foscarnet group than in the placebo group (p = 0.04), and the proportion of lesions that evolved to the vesicular stage was smaller (p = 0.03). No significant difference in the incidence of local or systemic adverse effects was noted between the two groups. We conclude that the beneficial effect of foscarnet was limited to a subgroup of patients who started treatment in the prevesicular stage. 相似文献
23.
The common mole-rat, Cryptomys h. hottentotus , is a social subterranean rodent occurring in colonies in which one female and one to three males are involved in reproduction and the remaining colony members are non-reproductive. Within each sex the reproductive animals are usually the largest and most dominant animals.
The dominance hierarchy amongst a field-captured colony was linear ( h = 0.95, calculated from Landau's linearity index) soon after capture. The non-reproductive females were ranked low in the dominance hierarchy; many were subordinate to non-reproductive males. The order of capture of mole-rats was not related to the position in the dominance hierarchy. The hierarchy became non-linear ( h = 0.56) after six months in captivity during which two juvenile animals became adult. The breakdown in the hierarchy may result from the lack of opportunity in captivity for animals to disperse and establish satellite colonies, or from colony members becoming co-dominant in the hierarchy as a result of a rise in rank by young animals.
Dominant mole-rats are involved in a greater proportion of interactive behaviours than subordinates. Popularity studies show that females tend to be more popular animals than males. The largest reproductive male was the least popular animal in the first study, whereas a beta male was the least popular animal in the second study period. The reproductive female was the most popular in both periods. 相似文献
The dominance hierarchy amongst a field-captured colony was linear ( h = 0.95, calculated from Landau's linearity index) soon after capture. The non-reproductive females were ranked low in the dominance hierarchy; many were subordinate to non-reproductive males. The order of capture of mole-rats was not related to the position in the dominance hierarchy. The hierarchy became non-linear ( h = 0.56) after six months in captivity during which two juvenile animals became adult. The breakdown in the hierarchy may result from the lack of opportunity in captivity for animals to disperse and establish satellite colonies, or from colony members becoming co-dominant in the hierarchy as a result of a rise in rank by young animals.
Dominant mole-rats are involved in a greater proportion of interactive behaviours than subordinates. Popularity studies show that females tend to be more popular animals than males. The largest reproductive male was the least popular animal in the first study, whereas a beta male was the least popular animal in the second study period. The reproductive female was the most popular in both periods. 相似文献
24.
Immunochemical detection of the alpha-subunit of the G-protein, GZ, in membranes and cytosols of mammalian cells 总被引:1,自引:0,他引:1
K Spicher K D Hinsch H Gausepohl R Frank W Rosenthal G Schultz 《Biochemical and biophysical research communications》1988,157(3):883-890
An antiserum (AS 98) was raised against a synthetic peptide deduced from published cDNA sequences of the alpha-subunit of the putative G-protein, GZ (Fong et al. Proc. Natl. Acad. Sci. USA 85, 3066-3070, 1988; Matsuoka et al. Proc. Natl. Acad. Sci. USA 85, 5384-5388, 1988). In membrane and cytosol preparations of many but not all tested mammalian tissues, AS 98 predominantly recognized two proteins of 40 and 43 kDa Mr. Whereas high levels of a 40 kDa GZ alpha-subunit were found in rat liver membranes and in brain cytosol, AS 98 failed to detect the alpha-subunit of GZ in brain membranes. 相似文献
25.
Human skin fibroblasts actively elongate a portion of incorporated C20 polyunsaturated fatty acids to their respective C22 derivatives. As much as 40% of incorporated [14C]eicosapentaenoate is elongated within 8 h and 85% by 48 h. Elongation of [14C]arachidonate is initially less than half that of [14C]eicosapentaenoate and plateaus at 20-30% of incorporated 14C-labeled fatty acid. The elongation of 5,8,11-[14C]eicosatrienoate is intermediate between that of 20:4(n-6) and 20:5(n-3). Docosatetraenoate is not an effective inhibitor of the elongation of arachidonate, thus suggesting that the observed plateau is not due to product inhibition. When concentrations of exogenous fatty acids are increased, these cells elongate substantial quantities of C20 polyunsaturated fatty acids; elongation of eicosapentaenoate is consistently more extensive than that of arachidonate. Eicosapentaenoate is also an effective inhibitor of the elongation of [14C]arachidonate. Increases in exogenous arachidonate up to 10 microM result in an increase in elongation of [14C]arachidonate both in absolute quantities and as a percentage of that incorporated; the arachidonate thus acts as a positive modulator of its own elongation. Increased eicosapentaenoate also enhances the elongation of [14C]eicosapentaenoate, but only at lower concentrations (0.02-0.15 microM). The factors which regulate the elongation of C20 polyunsaturated fatty acids in human skin fibroblasts serve to permit extensive elongation of eicosapentaenoate while retaining incorporated arachidonate primarily in its C20 form. 相似文献
26.
27.
H Friede R Matalon V Harris I M Rosenthal 《Journal of craniofacial genetics and developmental biology》1985,5(3):267-276
Serial roentgencephalograms of a male patient with Kniest dysplasia were obtained between 1 7/12 and 11 3/12 years of age and were analyzed and compared to cephalometric normative data. The patient displayed macrocephaly with increased size of the neurocranium in all three dimensions. The cranial base angle was significantly flattened, partly as a result of anterior displacement of the sella turcica. The odontoid process was short and wide. At 11 years of age there was bony fusion between the anterior arch of the atlas and the odontoid process as well as between the posterior arch of the atlas and the cranial base. The facial skeleton, including the nasal bones, infra-orbital rims, maxilla and mandible, was retropositioned relative to the anterior cranial base. The mandibular retrognathia was pronounced at an early age but improved with growth. At age 11 years the patient had a straight facial skeletal profile. Examination of the patient's 24-hour urinary excretion of keratan sulfate revealed values markedly elevated for his age. Three additional patients with Kniest dysplasia demonstrated similarly increased excretion of this glycosaminoglycan. The diagnosis of Kniest dysplasia can usually be made from roentgenograms of the extremities, the spine, and the pelvis. However, the morphologic characteristics of the head, as shown by cephalometric analysis, and the increased urinary excretion of keratan sulfate add confirmatory evidence useful in differential diagnosis. 相似文献
28.
Effect of free-radical and oxygen scavengers on photochemically generated oxygen toxicity and on the aerotolerance of Campylobacter jejuni 总被引:5,自引:5,他引:0
Exposure of a nutrient agar medium to the combined action of fluorescent light and air produced toxic factors in the medium which affected the growth of Campylobacter jejuni . Sodium dithionite (5–10 mM), a powerful reducing agent, and catalase were effective in counteracting the injurious action of light and air. Among the quenchers of singlet oxygen tested, only histidine had a beneficial effect on the recovery of C. jejuni in the photo-oxidized medium, while the addition of superoxide dismutase, a hydroxyl radical scavenger such as cysteamine, or the free radical antioxidants tocopherol and butylated hydroxy toluene, did not increase the recovery rate of photochemically injured cells. Histidine (40 mM) and dithionite (5–10 mM) also assisted recovery of C. jejuni inoculated on nutrient agar stored in air in the dark. Cysteamine and dithionite were toxic to Campylobacter when added at concentrations of ≥10 mM and ≥ 20 mM, respectively. A high inoculum of C. jejuni could not be recovered in unsupplemented nutrient agar incubated in air but was recovered in atmospheres containing 17 or 21% oxygen plus 10% carbon dioxide. The addition of dithionite, catalase or histidine resulted in some colony formation on nutrient agar incubated in air. Among the scavengers tested, only dithionite was consistently able to maintain the viability of C. jejuni on nutrient agar stored in air for longer than 4 weeks. In view of the ability of catalase, dithionite and histidine to enhance the aerotolerance of C. jejuni , it is concluded that various oxygen species might be involved in the toxicity of high levels of oxygen. 相似文献
29.
Cynthia Lenz D. L. Dahlman G. A. Rosenthal 《Archives of insect biochemistry and physiology》1986,3(3):265-275
Tobacco hornworm larvae, Manduca sexta (L.) (Sphingidae), were administered L-canaline either by parenteral injection or by dietary consumption. The overt toxicity and the alteration of hemolymph amino acids caused by these nonprotein amino acids were evaluated. The LD50 value for parenterally administered canavanine and canaline is 1.0 and 2.5 mg/g fresh body weight, respectively. A dietary concentration of 5.2 mM for canavanine and over 20 mM for canaline represent the respective LC50 values. A large percentage of the larvae reared on diets supplemented with additional arginine, ornithine, or 2,4-diaminobutyric acid in addition to canavanine or canaline were unable to complete larval-pupal ecdysis. These toxic effects were associated with a decreased glutamic acid hemolymph titer and dramatically elevated ornithine. On the other hand, larvae administered canavanine or canaline alone, either by dietary consumption or parenteral injection, experienced less drastic developmental aberrations. These symptoms were in some cases correlated with increased ornithine and glutamic acid titers. Evidence is presented that even a canavanine- and canaline-sensitive insect such as M. sexta has a marked ability to eliminate these protective allelochemicals. 相似文献
30.
Stuart J. Hamill David Y. Cooper Heinz Schleyer Otto Rosenthal 《Archives of biochemistry and biophysics》1983,224(2):614-624
The time-course kinetics of the cytochrome P-450-catalyzed dealkylations of the exogenous compounds benzphetamine, ethylmorphine, codeine, and 7-ethoxycoumarin were compared to the hydroxylation of the endogenous compound testosterone. Using liver microsomes from phenobarbital-induced rats, the time course of the demethylations of ethylmorphine, codeine, and especially benzphetamine was characterized by a fast initial phase of enzymatic activity and then a steady decline in the rate throughout the remainder of the reaction. In contrast, under the same experimental conditions, both the dealkylation of 7-ethoxycoumarin and the hydroxylation of testosterone showed no initial fast phase of activity and a constant rate of product formation for most of the remainder of the time course. The difference also held for the carbon monoxide inhibition studies in which the degree of inhibition of the demethylation reactions by a variety of CO:O2 mixtures was time dependent, in contrast to the constant, time-independent degree of CO inhibition of the other two reactions. The kinetics of the demethylation reactions could not be explained by enzyme destruction, back reaction, or product adduct formation and were further confirmed by measurements of the rate of O2 utilization and NADPH oxidation. The complexity of the demethylation reaction should be taken into consideration in any detailed studies of the monooxygenation reaction system. 相似文献