JM Zajac  D Gully  JP Maffrand 《Canadian Metallurgical Quarterly》1996,16(1-2):93-113

The binding and distribution of radiolabelled SR27897B, a potent CCK-A antagonist, was characterized using in vitro receptor autoradiography. Rapid imaging and quantitative analysis of [3H]SR27897B binding was obtained in a very short period of time (5 days) with a highly sensitive radioimager ensuring very short exposure times for isotopes such as tritium. Tritiated SR27897B binding sites are localized almost exclusively in the area postrema and the medical part of the nucleus tractus solitarius and in this nucleus the rostral-caudal distribution of CCK-A sites differed from that of sulphated CCK8 receptors. Receptor binding properties analyzed on 15 microns serial coronal sections showed on site receptor occupancy in these two regions with high affinity and selectivity characteristic of the CCK-A receptor. These results precisely locate the SR27897B binding sites and provide further support for the absence of heterogeneity of the CCK-A receptors in the rat brain.  相似文献   

    

M Radmacher  M Fritz  CM Kacher  JP Cleveland  PK Hansma 《Canadian Metallurgical Quarterly》1996,70(1):556-567

We have measured force curves as a function of the lateral position on top of human platelets with the atomic force microscope. These force curves show the indentation of the cell as the tip loads the sample. By analyzing these force curves we were able to determine the elastic modulus of the platelet with a lateral resolution of approximately 100 nm. The elastic moduli were in a range of 1-50 kPa measured in the frequency range of 1-50 Hz. Loading forces could be controlled with a resolution of 80 pN and indentations of the platelet could be determined with a resolution of 20 nm.  相似文献   

    

JP Leigh 《Canadian Metallurgical Quarterly》1996,73(2):370-397

What jobs are associated with the highest and lowest levels of cigarette use and of lung cancer? Are there gender differences in these jobs? Two data sets-the Epidemiological Follow-up to the National Health and Nutrition Examination Survey (NHEFS) and the California Occupational Mortality Study (COMS) were analyzed to answer these questions. For females, the broad occupations ranking from highest to lowest cigarette use in the NHEFS was: transportation operators, managers, craft workers, service workers, operatives, laborers, technicians, administrative workers, farm owners and workers, sales workers, no occupation, and professionals. The corresponding ranking for males was: transportation operators, no occupation, laborers, craft workers, service workers, technicians, and professionals. The highest-ranking jobs in the COMS were waitresses, telephone operators, and cosmetologists for women, and water-transportation workers, roofers, foresters and loggers for men. Teachers were especially low on all four lists. This study could not determine whether employment within any occupation encouraged smoking or if smokers selected certain occupations.  相似文献   

    

JE Golub  K Kash  JP Harbison  LT Florez 《Canadian Metallurgical Quarterly》1990,41(12):8564-8567

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JP Orlowski  D Lonsdale  RH Nodar  GW Williams 《Canadian Metallurgical Quarterly》1982,13(4):226-232

Thirty-six infants identified as infant apnea syndrome (IAS) and 25 controls with a comparable age distribution were evaluated with Brainstem Auditory Evoked Potential (BAEP) testing. There was a significant predilection for leftsided BAEP abnormalities in IAS patients. Fifteen IAS patients had bilateral abnormalities, and of the 21 IAS patients with unilateral abnormalities, 17 had abnormalities on the left side (p less than 0.01 by McNemar's test). Significant differences (p less than 0.05 by analysis of covariance adjusting for age) between normal controls and IAS infants were found for peak latencies I, III, and V, and amplitude III. Linear regression analyses of the above parameters versus age in months for normal controls were constructed with 68% and 95% prediction interval bands to permit analysis of individual data points. Data points from the IAS infants with bilateral BAEP abnormalities have been plotted on these linear regression curves. No single measurement of latency or amplitude is abnormal in the majority of IAS infants, but many of the individual points fall outside of the 95% prediction curve.  相似文献   

    

JP Leburton 《Canadian Metallurgical Quarterly》1988,38(6):4085-4095

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M Schossmann  E Schachinger  JP Carbotte 《Canadian Metallurgical Quarterly》1987,36(16):8360-8364

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  总被引：1，自引：0，他引：1  

A Lane  F Green  PY Scarabin  V Nicaud  L Bara  S Humphries  A Evans  G Luc  JP Cambou  D Arveiler  F Cambien 《Canadian Metallurgical Quarterly》1996,119(1):119-127

Ribosome-inactivating proteins (RIPs) are naturally occurring plant toxins that exhibit antiviral activity against a diverse range of plant and animal viruses. Here, the action of dianthin, a potent RIP isolated from Dianthus caryophyllus, has been exploited to engineer resistance to a plant DNA virus, African cassava mosaic virus (ACMV), in transgenic Nicotiana benthamiana. To achieve this, dianthin has been expressed from the ACMV virion-sense promoter that is transactivated by the product of viral gene AC2. This avoids the need for constitutive expression of the RIP, facilitating the regeneration of phenotypically normal plants, and ensures transgene expression is localized to virus-infected cells. When challenged with ACMV, transgenic plants produce atypical necrotic lesions on inoculated leaves, indicative of dianthin expression, viral DNA accumulation is significantly reduced in these tissues, and plants exhibit attenuated systemic symptoms from which they recover. This phenotype holds for isolates of ACMV but not for other geminiviruses, suggesting that AC2 homologues from the latter are unable to efficiently transactivate the ACMV promoter.  相似文献   

    

JA Auer  JP Watkins 《Canadian Metallurgical Quarterly》1996,12(2):283-302

In recent years fracture fixation in the horse has changed significantly. New devices, mainly adapted from the human field, have been successfully introduced into large animal surgery. Examples of such implants include the DCS/DHS implant system, the self-tapping screw, the cannulated screw, and the pinless external fixator. However, new devices have also been developed exclusively for equine fracture management, including the interlocking intramedullary nail and the external skeletal fixation device. With these devices the surgeon has more options for repairing fractures in horses. Nevertheless, many problems are still unsolved. Indications exist that during the next few years new, exciting fracture fixation systems will be developed, providing further advancements in the quest for the ideal implant for horses. However, the development stages of these devices are such that mentioning the possibilities here is premature.  相似文献   

    

JA Monn  MJ Valli  BG Johnson  CR Salhoff  RA Wright  T Howe  A Bond  D Lodge  LA Spangle  JW Paschal  JB Campbell  K Griffey  JP Tizzano  DD Schoepp 《Canadian Metallurgical Quarterly》1996,39(15):2990-3000

The four isomers of 4-aminopyrrolidine-2,4-dicarboxylate (APDC) were prepared and evaluated for their effects at glutamate receptors in vitro. (2R,4R)-APDC (2a), an aza analog of the nonselective mGluR agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylate (1S,3R)-ACPD, 1), was found to possess relatively high affinity for metabotropic glutamate receptors (mGluRs) (ACPD-sensitive [3H]glutamate binding IC50 = 6.49 +/- 1.21 microM) with no effects on radioligand binding to NMDA, AMPA, or kainate receptors up to 100 microM. None of the other APDC isomers showed significant mGluR binding affinity, indicating that this interaction is highly stereospecific. Both 1 and 2a were effective in decreasing forskolin-stimulated cAMP formation in the adult rat cerebral cortex (EC50 = 8.17 +/- 2.21 microM for 1; EC50 = 14.51 +/- 5.54 microM for 2a); however, while 1 was also effective in stimulating basal tritiated inositol monophosphate production in the neonatal rat cerebral cortex (EC50 = 27.7 +/- 5.2 microM), 2a (up to 100 microM) was ineffective in stimulating phosphoinositide hydrolysis in this tissue preparation, further supporting our previous observations that 2a is a highly selective agonist for mGluRs negatively coupled to adenylate cyclase. Microelectrophoretic application of either 1 or 2a to intact rat spinal neurons produced an augmentation of AMPA-induced excitation (95 +/- 10% increase for 1, 52 +/- 6% increase for 2a). Intracerebral injection of 1 (400 nmol) produced characteristic limbic seizures in mice which are not mimicked by 2a (200-1600 nmol, ic). However, the limbic seizures induced by 1 were blocked by systemically administered 2a in a dose-dependent manner (EC50 = 271 mg/kg, ip). It is concluded that (2R,4R)-APDC (2a) is a highly selective, systemically-active agonist of mGluRs negatively coupled to adenylate cyclase and that selective activation of these receptors in vivo can result in anticonvulsant effects.  相似文献