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1.
Injections of octopamine, dopamine, and the octopaminergic agonists, clonidine and naphazoline, into the thoracic hemocoel enhanced female insemination in sugar-fed (sexually unreceptive)Phormia regina. Topical applications of the juvenile hormone (JH) analogue, methoprene, also enhanced female insemination in sugar-fed (sexually unreceptive)P. regina. Since JH plays a role in receptivity in protein-fed females, it was originally hypothesized that one agonist, clonidine, enhanced female insemination by acting on the corpus allatum (CA) to increase JH biosynthesis. Two or three doses of the antiallatal agent, precocene II, prior to administration of clonidine, did not inhibit clonidine-enhanced female insemination. Removal of the corpus allatum also did not have a significant effect on clonidine-enhanced female insemination. Measurement of juvenile hormone (JH) biosynthesis/release in corpora allata, which were removed at 1, 3, 5, and 7 h postinjection, revealed that clonidine does not affect JH biosynthesis/release. Our study reveals a possible role for the biogenic amines in female insemination in insects. We suggest that the octopaminergic agonist, clonidine, acts downstream from the corpus allatum on the regulatory mechanisms involved in female insemination.  相似文献   

2.
Serotonin is an important signaling molecule involved in the control of feeding in flies and other animals. In this study, a potential neurohemal release site for serotonin and the effects of exogenous serotonin on protein feeding were examined in the black blow fly, Phormia regina. A dense network of varicose neural processes exhibiting serotonin-like immunoreactivity was identified on the dorsal region of the thoracico-abdominal ganglion in P. regina. This dorsal region of the central nervous system is a likely site for the release of serotonin into the hemolymph. Circulating serotonin may have multiple systemic effects on fly physiology, including modulating or regulating feeding related processes and diuresis. Injections of exogenous serotonin reduced protein meal size in female flies at all doses and at all time points examined within a 24 h period relative to control and saline injected flies. Similar results were observed in serotonin-injected males at 35 min post injection. The injection of 50 μg serotonin resulted in the greatest amount of protein feeding inhibition. Serotonin injected flies also experienced greater weight loss than control or saline-injected flies during the 24 h post-injection period, possibly due to increased diuresis.  相似文献   

3.
The effect of various doses of luteinizing hormone-releasing hormone analogue (LHRHa) ranging from 1 to 100 μg/kg body weight on the spawning response of mature female sea bass, Lates calcarifer (Bloch) was tested. A single intramuscular injection of LHRHa resulted in a dose-related increase in the spawning rate (number of spawnings of each fish over four consecutive days) of mature fish. An LHRHa dose of 5 μg/kg and less induced low spawning rates of 16.7% to 37.5% or at least one spawning every four days. However, mature sea bass spawned more than once (43.8–58.3%) in four days at dose levels of 10 μg/kg and above. Hormone treatment within the dose range tested did not influence the number, fertilization and hatching rates of spawned eggs. The influence of initial oocyte size on the LHRHa-induced spawning response of mature sea bass was also examined. Sea bass with an initial oocyte diameter of 0.30–0.39 mm did not respond to the single injection of 100 μg LHRHa/kg. In contrast, LHRHa induced spawning among sea bass with an initial egg size of 0.40–0.49 mm, although two of four sea bass of the same stage of ovarian maturity spawned spontaneously. Fish having an initial oocyte size of 0.50–0.55 mm spawned with and without LHRHa treatment. Spontaneous spawning among saline-injected sea bass occurred at a later time (24–58 h post-injection) compared to fish induced to spawn by a single injection of LHRHa (8–36 h post-injection). The initial spawning response time interval for fish with an initial egg size of 0.50 mm or greater was further reduced to 8–9 h by LHRHa. These results indicate that LHRHa can successfully induce spawning in mature female sea bass which have attained a critical oocyte diameter and that the spawning response interval is reduced with a further increase in egg size beyond the critical oocyte diameter limit.  相似文献   

4.
This research was undertaken to improve development of parthenogenetic embryos following various combined treatments of ethanol and cycloheximide. In Experiment 1 in vitro matured oocytes (IVM, 24 hr) were treated with 7% ethanol for 5 min followed by incubation in 10 μg/ml cycloheximide in Medium 199 for 0 (control), 5, 10, and 20 hr. Development to 2–8 cells following culture for 3 days was similar among treated groups (32–41%; P > 0.05), which was higher than that of controls (6%; P < 0.05). Experiment 2 compared pre-ethanol exposures for 0, 1, 2.5, and 5 min, followed by 5 hr cycloheximide treatment on activation development. One- to 5-min groups resulted in 42–44% cleavage contrasted to 1–12% for controls (P < 0.05). Experiment 3 examined the effect on oocyte development of ethanol and different concentrations of cycloheximide (0, 1, 5, and 10 μg/ml). Cleavage to 2–8 cells was similar among the 5 and 10 μg/ml cycloheximide groups (36% and 42%, P > 0.05) but lower (P < 0.05) for the 1 μg/ml group (24%) and the controls (2–13%). When 5 μg/ml cycloheximide was used (Experiment 4), pre-exposure to ethanol (1, 2.5, and 5 min) resulted in more oocytes cleaved (38–41%) than in the cycloheximide alone group (0%) or the control (0%, P < 0.05). Experiment 5 tested blastocyst development of the activated oocytes with or without cytochalasin B treatment. Oocytes developed to blastocyts were 0%, 14%, 3%, and 3% (P < 0.05), respectively, for control, treatment with ethanol and cycloheximide in the presence, or absence of cytochalasin B, or electrical pulse plus cycloheximide. In conclusion, the combined ethanol and cycloheximide treatment supported high rates of parthenogenetic development using 24 hr IVM bovine oocytes. Blastocyst rate was significantly higher when cytochalasin B was added to the combined activation regimen. © 1994 Wiley-Liss, Inc.  相似文献   

5.
The effects of exposure of pig oocytes to an electrical pulse on sperm penetration and pronuclear formation were determined before or after in vitro fertilization (IVF). After in vitro maturation (IVM) or after collection from oviducts of unmated gilts, pig oocytes either were not exposed or were exposed to an electrical pulse (a 10 sec pulse at 4.0 V mm?1 AC followed by a 30 μsec pulse at 120 V mm?1 DC), followed 30 min later by IVF. The incidence of male pronuclear formation of both IVM and in vivo-matured oocytes at 12 hr after insemination was decreased from 59% and 100%, respectively, to 2% and 36%, respectively, by the electrical pulse, but the penetration rates (88–100%) and polyspermic rates (79–100%) were not affected by exposure to an electrical pulse. Similarly, when pig IVM oocytes were exposed to an electrical pulse at 6 hr after insemination, electrical activation did not decrease penetration rates (93% vs. 90%), polyspermic rates (83% vs. 91%), or number of spermatozoa in penetrated oocytes (4.0 ± 0.5 vs. 4.6 ± 0.5) but did decrease the rate of male pronuclear formation from 58% to 18%. When oocytes were examined at 6 hr after insemination, 75% of them had been penetrated and resumed meiotic progression, but all sperm heads in penetrated oocytes were fully condensed or only partially decondensed. The percentage of penetrated eggs with multiple female pronuclei was increased when oocytes were exposed to an electrical pulse in all experimental series. In summary, electrical activation of pig oocytes before or just after IVF does not prevent sperm penetration but does inhibit male pronuclear formation and increases the formation of multiple female pronuclei. © 1993 Wiley-Liss, Inc.  相似文献   

6.
Developing erythroid cells of the goldfish Carassius auratus were obtained from kidney prints and from smears of the peripheral blood. All preparations were stained with the May-Grunwald Giemsa technique. Developing cells were divided into six different stages. The criteria used to stage the cells were degree of chromatin condensation, degree of basophilia, nuclear:cytoplasmic ratio, and cell shape. The morphology of the maturation sequence for erythroid cells in this organism was similar to that found by other workers in other non-mammalian vertebrates. Fish received intraperitoneal injections of tritiated thymidine, tritiated uridine or tritiated leucine so that the stages involved in DNA synthesis, RNA synthesis and protein synthesis could be determined by means of autoradiography. For the tritiated thymidine studies the per cent labeled cells per stage from four different series receiving 0.5, 1.0, 3.0 or 6.0 μCi/g body weight were pooled, since subjecting the average per cent labeled cells per stage at the lowest and at the highest dosages to Student's t-test showed no significant differences. In all four series the fish were killed 2 hr, 12 hr and daily, 1–8 days post-injection. The 3H-TdR studies showed that stages I-IV were engaged in DNA synthesis; they also showed that about 5 days were required for the stage V cell to become a mature erythrocyte (stage VI cell). Tritiated uridine was injected at a dosage of 5.0 μCi/g body weight and animals were killed 1/2, 1, 3 and 6 hr post-injection. Grain counts showed that stages I-IV are engaged in RNA synthesis and that the rate of this synthesis decreased as maturation proceeded. Tritiated leucine was administered at a dosage of 5.0 μCi/g body weight, and fish were killed 45 min and 3 hr post-injection. Grain counts indicate that stages I-V are engaged in the synthesis of protein (assumed to be globin). The fact that DNA and RNA synthesis ceased with stage IV cells while protein synthesis continued into stage V cells indicated that the mechanism responsible for protein synthesis in stage V cells was produced at an earlier stage and was self-sustained for about 5 days.  相似文献   

7.

Background

In patients with relapsing–remitting multiple sclerosis (RRMS), subcutaneous (sc) interferon (IFN)β-1a and IFNβ-1b have been shown to reduce relapse rates. A formulation of IFNβ-1a has been produced without fetal bovine serum and without human serum albumin as an excipient (not currently approved for use in the US). The objectives of this study were to evaluate tolerability, injection-site redness, subject-reported satisfaction with therapy, and clinical safety and efficacy of the serum-free formulation of IFNβ-1a versus IFNβ-1b in IFNβ-treatment-naïve patients with RRMS. The objectives of the extension phase were to evaluate long-term safety and tolerability of IFNβ-1a.

Methods

This randomized, parallel-group, open-label study was conducted at 27 clinical sites in the US. Eligible patients aged 18–60 years were randomized to receive either IFNβ-1a, titrated to 44 μg sc three times weekly (tiw) (n = 65), or IFNβ-1b, titrated to 250 μg sc every other day (n = 64) over 12 weeks. Following this, all patients received IFNβ-1a 44 μg tiw for 82–112 weeks. Primary endpoint was mean change in patient-reported pain, as assessed by visual analog scale (VAS) diary pain score (from 0 mm [no pain] to 100 mm [worst possible pain]) at the injection site, from pre-injection to 30 min post-injection over the first 21 full-dose injections. Secondary assessments included proportion of patients pain-free as recorded by VAS diary and the Short-Form McGill Pain questionnaire VAS.

Results

A total of 129 patients were included in the intent-to-treat analysis. Mean (standard deviation) change in VAS diary pain score was not significantly different between groups, although numerically lower with IFNβ-1a versus IFNβ-1b from pre-injection to immediately post-injection (1.46 [2.93] vs. 4.63 [10.57] mm), 10 min post-injection (0.70 [1.89] vs. 1.89 [5.75] mm), and 30 min post-injection (0.67 [2.32] vs. 1.14 [4.94] mm). Proportion of patients pain-free at all time periods post-injection was also not significantly different between groups. Adverse events were consistent with the known safety profiles of these treatments.

Conclusions

In IFNβ-treatment-naïve patients with RRMS, both the serum-free formulation of IFNβ-1a and IFNβ-1b treatments were generally accompanied by low-level injection-site pain and were well tolerated.

Trial registration

ClinicalTrials.gov NCT00428584
  相似文献   

8.
Four experiments were replicated 1) to establish dose-response relationships between lysophosphatidylcholine (LPC), sperm motility, and the acrosome reaction (AR), 2) to evaluate the influence of rabbit serum (RS) on these endpoints, 3) to compare buck differences in induction of the AR, and 4) to examine fertilizing ability in vitro of sperm tested under the first three objectives. Semen was collected from Dutch-belted rabbits, washed once by centrifugation, resuspended, and preincubated for 2 or 4 hr in a chemically defined medium (DM), DM plus 20% RS, or BSA-free DM plus 20% RS at 37°C. At the end of preincubation LPC was added to the preincubated sperm at concentrations of from 0 to 100 μg/ml. Sperm were examined .5–4 hr later for AR and sperm motility. For in vitro fertilization, sperm and ova were coincubated in DM up to 24 hr after insemination and in a more complex medium for another 24 hr. Addition of LPC to 4-hr-preincubated sperm was more effective for inducing the AR than addition to 2-hr-preincubated sperm. A significant increase (P < .05) in the AR occurred in 15 and 30 min following exposure to 100 and 80 μg of LPC per ml, respectively, but the higher concentration of LPC decreased sperm motility. Addition of 20% RS to DM with or without BSA surprisingly inhibited the AR but maintained sperm motility, as expected. Bucks differed (P < .05) in the initial percentage and the induced percentage of AR sperm. For the AR the optimal concentration of LPC per ml was 80 μg, but for in vitro fertilization 60 μg tended to be superior.  相似文献   

9.
Aims: To measure antibacterial activity of the semi-synthetic flavonoid 3-O-octanoyl-(–)-epicatechin and investigate the mechanism of action. Methods and Results: MICs determined by the broth microdilution method were 50 μg ml−1 for β-lactam sensitive and resistant Staphylococcus aureus, and 100 μg ml−1 for vancomycin sensitive and resistant enterococci. In time-kill studies, 100 μg ml−1 3-O-octanoyl-(–)-epicatechin reduced colony forming unit numbers of antibiotic sensitive and methicillin-resistant Staph. aureus below detectable levels within 120 min. Bacterial aggregation was not observed when cells exposed to 3-O-octanoyl-(–)-epicatechin were examined by light microscopy. It was also shown that 50 μg ml−1 3-O-octanoyl-(–)-epicatechin is capable of reducing colony forming unit numbers of high cell density Staph. aureus populations by 80-fold within 60 min incubation, and inducing leakage of 50% of their internal potassium within just 10 min. Conclusions: 3-O-Octanoyl-(–)-epicatechin is active against Gram-positive bacteria, has bactericidal activity against both antibiotic sensitive and resistant strains, and is likely to exert its primary antibacterial effect by damaging the cytoplasmic membrane. Significance and Impact of the Study: 3-O-Octanoyl-(–)-epicatechin has significant antibacterial activity and additional structural modification and/or formulation studies may allow this to be potentiated.  相似文献   

10.
The research was undertaken to develop a successful nonsurgical procedure for artificially inseminating ferrets. A fiberoptic endoscope used in conjunction with a specially designed speculum and catheter permitted cervical catheterization and intrauterine insemination. Sperm were collected from the cauda epididymides of 10 discarded breeder males; the number of sperm in diluted samples used for insemination ranged from 4.4–13.6 × 106/100 μl with progressive motility of sperm ranging from 40 to 60%. Sperm collected from each male were diluted with an egg-yolk extender (TEST) and used to inseminate 8–12 females, with deposition of sperm intravaginally or transcervically into the uterine body 0 or 24 hr after an ovulatory injection of human chorionic gonadotropin (hCG). The vaginal inseminations were used as a control, and no pregnancies resulted after insemination of 26 females. Intrauterine inseminations resulted in 4/24 (17%) of the ferrets pregnant when hCG administration was coincident with insemination, and 19/24 (79%) of the ferrets were pregnant when inseminations were done 24 hr after hCG administration. All inseminated females were euthanized on day 20 after insemination to count fetuses. The mean number of fetuses was 3.1 (range, 1–8). The number (millions) of motile sperm inseminated (X) had a significant effect on the percentage of fetuses (Y). Regression analysis indicated a linear relationship between the two variables, with an R2 value of 0.99 and a line of best fit described by the equation Y = 0.029 + 0.034 X. This paper is the first report of transcervical artificial insemination in the domestic ferret (Mustela putorius furo). The method can serve as a model for application to ferrets and other mammals, particularly endangered species. Zoo Biol 17:393–404, 1998. © 1998 Wiley-Liss, Inc.  相似文献   

11.
Watercress chlorotic leaf spot virus (WCLV) caused a yellow leaf spot disease of watercress at Pickering, Yorkshire. The virus was mechanically transmitted to and maintained in Chenopodium quinoa, C. amaranticolor and Petunia hybrida in which it caused systemic symptoms. It could not be mechanically transmitted, however, from infected C. quinoa to Chrysanthemum, Gynura aurantia, potato, tomato, watercress or nine other species of Cruciferae. WCLV could be partially-purified after extraction in weak (0.05–0.1 M) but not strong (0.5 M) phosphate or tris/HCl buffer after clarification with diethyl ether and acidification to pH 3.9–4.0. Preparations were non-infective if treated with 5% (vlv) ethanol or n-butanol or if stored at — 12°C for 1 day or heated for 10 min at 54°C. Preparations were non-infective after treatment with RNase or proteinase K but not after treatment with DNase. The virus was present in roots of diseased watercress plants which also contained the watercress crook root disease fungus Spongospora subterranea f. sp. nasturtii. Tests showed that WCLV was transmitted by S. subterranea zoospores and that it persisted in the resting spores of the fungus. The crook root disease was controlled by adding 0.3–0.5 μg Zn/ml to the inlet water supply to the crop. The water that had flowed through the crop contained 0.05–0.10 μg Zn/ml. Although this increased the zinc content of the watercress from 8–9 in untreated beds to 16–48 μg Zn/g in treated beds, this was below the tolerance recommended by the Food Standards Committee. A method is described of obtaining accurate dilutions of solutions of zinc sulphate (20% w/v ZnSO4.H2O) in the water supplying the crop using solutions of the red dye Ariavit Amaranth.  相似文献   

12.
Selenium, as an essential trace element, interferes through selenoproteins in many physiological processes of plants and mammals. Its antiviral activity has recently attracted much attention because selenium improves the antiviral capacity of animal cells against a few viruses relevant to human diseases. In this study, the red elemental selenium was purified from the fermentative culture of Herbaspirillum camelliae WT00C and then used to culture epithelioma papulosum cyprinid (EPC) cells or feed crucian carp and zebrafish. Finally, its antiviral effects were investigated at the cell level and living fishes after spring viraemia of carp virus infection. At the cell level, 5, 10 and 20 μg ml–1 red elemental selenium significantly induced the expression of interferon (IFN) and ISG15 genes in EPC cells. The viral TCID50 (50% tissue culture infective dose) values in the EPC cells incubated with 5, 10 and 20 μg ml–1 red elemental selenium were significantly less than those of the control. More expression of IFN and ISG15 genes and less TCID50 values indicate that red elemental selenium indeed improves the antiviral capability of EPC cells. In the crucian carp fed with the food containing 5 and 10 μg g–1 red elemental selenium, IFN expressions showed 13- and 39-fold increases at the 16th day of post-injection, and its expression was dependent on selenium concentrations. Meanwhile, no fish death occurred in all the experimental groups. In the zebrafish fed with the red worm containing 5 μg g–1 red elemental selenium, IFN and Mx expressions and survival rate were significantly higher than those of the control. The results of this study show that red elemental selenium indeed improves the antiviral activity of fish. The antiviral effects of selenium mainly come from its immune regulation through its incorporation into selenoproteins. The optimum level of selenium contributes to improving fish immunity, whereas excess selenium causes excessive immune and inflammatory responses.  相似文献   

13.
Summary

The possibility that biogenic amines affect ovarian development in the red swamp crayfish, Procambarus clarkii, was investigated. Females were administered 15 μg/g body weight (bw) of norepinephrine, dopamine, 5-hydroxytryptamine (5-HT) or octopamine on days 1, 5 and 10 and were sacrificed on day 15. Crayfish given 5-HT showed significant increases in ovarian index (30.5%) and oocyte size (34.0%) over the concurrent controls, while norepinephrine, dopamine and octopamine did not significantly affect either the ovarian index or oocyte size. Significantly more labeling by 14C-leucine of ovarian proteins was found in ovaries of crayfish that were injected with 5-HT in vivo, but when ovarian lobes from crayfish that had not been injected with 5-HT were incubated in vitro with 5-HT added to the incubation medium, no significant change in the level of incorporation of 14C-leucine into ovarian proteins occurred.

The 5-HT receptor blocker LY53857 (25 μg/g bw) retarded ovarian development. The 5-HT releaser fenfluramine and the 5-HT potentiator fluoxetine (both 15 μg/g bw) were also used. Crayfish given fenfluramine, fluoxetine, fenfluramine plus 5-HT or fluoxetine plus 5-HT showed significant increases of ovarian index (24.0–102.8%), oocyte size (20.0–87.4%) and in vitro 14C-leucine labeling of ovarian proteins (30.6–123.6%) over the concurrent controls. The ovaries of crayfish that received the 5-hydroxytryptaminergic neurotoxin 5,6-dihydroxytryptamme (10 μg/g bw) did not show any significant change as compared with the initial control. These findings are consistent with the hypothesis that 5-HT, which is present in the central nervous system of Procambarus clarkii, exerts its stimulatory effect on the ovary of this crayfish indirectly by triggering release of the ovary-stimulating hormone.  相似文献   

14.
Abstract: The specific opioid receptor antagonist naloxone attenuates the behavioral and neurochemical effects of amphetamine. Furthermore, the amphetamine-induced increase in locomotor activity is attenuated by intracisternally administered naltrindole, a selective δ-opioid receptor antagonist, but not by the irreversible μ-opioid receptor antagonist β-funaltrexamine. Therefore, this research was designed to determine if naltrindole would attenuate the neurochemical response to amphetamine as it did the behavioral response. In vivo microdialysis was used to monitor the change in extracellular concentrations of dopamine in awake rats. Naltrindole (3.0, 10, or 30 µg) or vehicle was given 15 min before and β-funaltrexamine (10 µg) or vehicle 24 h before the start of cumulative dosing, intracisternally in a 10-µl volume, while the rats were lightly anesthetized with methoxyflurane. Cumulative doses of subcutaneous d-amphetamine (0.0, 0.1, 0.4, 1.6, and 6.4 mg/kg) followed pretreatment injections at 30-min intervals. Dialysate samples were collected every 10 min from either the striatum or nucleus accumbens and analyzed for dopamine content by HPLC. Amphetamine dose-dependently increased dopamine content in both the striatum and nucleus accumbens, as reported previously. Naltrindole (3.0, 10, and 30 µg) significantly reduced the dopamine response to amphetamine in the striatum. In contrast, 30 µg of naltrindole did not modify the dopamine response to amphetamine in the nucleus accumbens. On the other hand, β-funaltrexamine (10 µg) had no effect in the striatum but significantly attenuated the amphetamine-induced increase in extracellular dopamine content in the nucleus accumbens. These data suggest that δ-opioid receptors play a relatively larger role than μ-opioid receptors in mediating the amphetamine-induced increase in extracellular dopamine content in the striatum, whereas μ-opioid receptors play a larger role in mediating these effects in the nucleus accumbens.  相似文献   

15.
Investigations were carried out to examine more closely the aggregations of microfilaments associated with the elongation of microvilli and formation of fertilization cones and the effects of cytochalasin B (CB) on these processes in Arbacia eggs following insemination. At 1 to 5 min postinsemination fertilized eggs were treated with 1–10 μg/ml CB and then prepared for electron microscopy at periodic intervals. Examination of CB-treated and untreated specimens demonstrated that: (1) Reorganization of the egg's microvilli took place soon after insemination; this process, as well as formation of fertilization cones, was correlated with the appearance of fascicles of microfilaments. (2) CB inhibited the formation of fertilization cones and the elongation of microvilli. Bundles of microfilaments were not observed in CB-treated zygotes. (3) CB prevented the normal movements (rotation) of the incorporating spermatozoon into the egg cortex but did not inhibit the migration or fusion of the male and female pronuclei.  相似文献   

16.
Nickel concentrations (μ g/g, dry weight) in the scalp hair of vegetable oil– and hydrogenated oil–consuming categories of male and female donors, ages between 1–66 years, were estimated by the atomic absorption method to assess the contribution of nickel as a contaminant in the hydrogenated oil. Comparative estimates of hair Ni content revealed enhanced metal levels for donors consuming hydrogenated oil both for male (29.33 μg/g, dry weight) and female (27.09 μg/g, dry weight) population segments, whereas for oil-consuming donors the corresponding levels were 11.51 μg/g and 13.49 μg/g, respectively. The Ni content of hair of elderly donors consuming hydrogenated oil was found significantly higher than that of younger male/female donors. Hair Ni levels as high as 63.59 μg/g and 68.40 μg/g were estimated for hydrogenated oil–consuming males and females, respectively. The Ni concentrations exhibited strong positive correlation with age for the hydrogenated oil–consuming male (r = 0.713) and female (r = 0.707) categories, whereas negative correlations were found for both oil-consuming categories. The regression relationships linking hair nickel content with the donor age of either sex indicated a negative dependence for oil-consuming donors, whereas strong direct dependence was observed for hydrogenated oil-consuming donors. The overall results evidenced an index of elevated nickel levels in the hair of population segment consuming hydrogenated oil, believed to arise from excessive residual nickel in the hydrogenated oil, present at concentrations surpassing the limit recommended by the World Health Organization for the safe ingestion of nickel in food commodities.  相似文献   

17.
Repeated trunk injections of tetracycline hydrochloride and oxytetra-cycline over a 27 month period, retarded the rate at which clove trees in Zanzibar, died from sudden death (SD) disease. This result provides additional support for an MLO aetiology for SD, but indicates that the tetracycline formulations and method of application, as described here, is not a feasible method of SD control in the field. Bioassay of leaf discs and root sections using agar plates seeded with Bacillus subtilis, at various times after injection, indicated that antibiotic distribution to the canopy was extensive, but that down to the roots was minimal. The proportion of leaf discs showing tetracycline activity declined over a 54 day period post-injection, from 75,% to 17%. Mean tetracycline levels in leaves per tree peaked at 2.4 μg/ml, 21 days after injection. The highest individual leaf disc level was 7 μg/ml. Most trees maintained concentrations of tetracycline inhibitory to B. subtilis growth for 2,1–41 days.  相似文献   

18.
The subcellular distribution of radiocopper in the brain and liver of rats has been determined following i.v. administration of Cu-PTSM, pyruvaldehyde bis(N4-methylthiosemicarbazonato)copper(II), labeled with copper-67. Homogenized tissue samples were separated by differential centrifugation into four subcellular fractions: (I) cell membrane + nuclei; (II) mitochondria; (III) microsomes; and (IV) cell cytosol. Upon sacrifice at 10 min post-Cu-PTSM injection, brain fractions, I, II, III and IV contain 35 ± 12, 11 ± 3, 2.8 ± 1.3 and 51 ± 7% of brain activity, respectively (n = 4). In animals sacrificed 24 h post-injection the subcellular fractions of brain tissue show little change from the radiocopper distribution seen at 10 min post-injection, although the mitochondrial fraction may contain slightly more tracer and the cytosolic fraction slightly less (I, 40 ± 10%; II, 18 ± 5%; III, 3.4 ± 1.5%; and IV, 38 ± 5%; n = 5). Subcellular fractions I, II, III and IV of liver contain 25 ± 5, 12 ± 3, 17 ± 4 and 46 ± 6% of 67Cu tracer in animals sacrificed 10 min post-Cu-PTSM injection. An identical subcellular distribution of 67Cu, was found in the liver following i.v. administration of ionic radiocopper (as Cu-citrate). The liver and brain cytosolic fractions at 10 min post-injection were further separated by Sephadex column chromatography. In liver cytosol, three different radiocopper components with molecular weights of about 140,000, 41,000–46,000 and 10,000–16,000 Da were found. In the brain supernatant fraction, most of the radiocopper was bound to a single low molecular weight cytosolic component (14,000–16,000 Da). These results suggest that the intracellular decomposition of tracer Cu-PTSM may result in the radiocopper entering the normal cellular pools for copper ions.  相似文献   

19.
A new ligand, an N-p-iodophenethyl diaminodithiol (DADT-IPE), an anlog of N-isopropyl-p-iodoamphetamine (IMP), was synthesized and subsequently complexed with 99mTc, using stannous chloride as a reducing agent. Two complexes (a and b) were separated from 99mTc-DADT-IPE by high performance liquid chromatography (HPLC). Competitive inhibition studies showed that the IC50 value of DADT-IPE (70 μM) was similar to that of IMP (49 μM). Biodistribution studies of one of the complexes [99mTc-DADT-IPE(a)] in rats showed that 0.65% of the injected dose of the tracer remained in the brain at 5 min after intravenous injection, with 0.53% of the dose remaining in the brain at 60 min post-injection, whereas the corresponding values for the other complex [99mTc-DADT-IPE(b)] were 0.34% dose in the brain at 5 min and 0.28% dose in the brain at 60 min post-injection. The half-life for clearance of 99mTc-DADT-IPE(a) from rat brain was found to be more than 5 h. These results suggested that 99mTc-DADT-IPE(a) has characteristics which are suitable for cerebral perfusion imaging.  相似文献   

20.
The use of columns packed with sub‐2 μm particles in liquid chromatography with very high pressure conditions (known as UHPLC) was investigated for the fast enantioseparation of drugs. Two different procedures were evaluated and compared using amphetamine derivatives and β‐blockers as model compounds. In one case, cyclodextrins (CD) were directly added to the mobile phase and chiral separations were carried out in less than 5 min. However, this strategy suffered from several drawbacks linked to column lifetime and low chromatographic efficiencies. In the other case, the analysis of enantiomers was carried out after a derivatization procedure using two different reagents, 2,3,4‐tri‐O‐acetyl‐α‐D ‐arabinopyranosyl isothiocyanate (AITC) and N‐α‐(2,4‐dinitro‐5‐fluorophenyl)‐L ‐alaninamide (Marfey's reagent). Separation of several amphetamine derivatives contained within the same sample was achieved in 2–5 min with high efficiency and selectivity. The proposed approach was also successfully applied to the enantiomeric purity determination of (+)‐(S)‐amphetamine and (+)‐(S)‐methamphetamine. Similar results were obtained with β‐blockers, and the separation of 10 enantiomers was carried out in less than 3 min, whereas the individual separation of several β‐blocker enantiomers was performed in 1 min or less. Chirality, 2010. © 2009 Wiley‐Liss, Inc.  相似文献   

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