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1.
In the feline gastrointestinal tract, the neuropeptides, substance P, VIP and PHI were investigated by specific radioimmunoassays and immunocytochemistry. The concentrations of all 3 peptides and the level of peptidergic innervation were significantly less in the anal sphincter than elsewhere, whereas no significant differences were seen between other sphincter and non-sphincter regions.  相似文献   
2.
Summary After experimental lesions inGalago crassicaudatus, the cortico-efferent fibres of the optical cortex were studied using theNauta andGlees methods. Mainly 4 different systems were separated: Corticocaudate, pontine, geniculate and pulvinar.  相似文献   
3.
Anthrax has been a major cause of death in grazing animals and an occasional cause of death in humans for thousands of years. Since the late 1800s there has been an exceptional international history of anthrax vaccine development. Due to animal vaccinations, the rate of infection has dropped dramatically. Anthrax vaccines have progressed from uncharacterized whole-cell vaccines in 1881, to pXO2-negative spores in the 1930s, to culture filtrates absorbed to aluminum hydroxide in 1970, and likely to recombinant protective antigen in the near future. Each of these refinements has increased safety without significant loss of efficacy. The threat of genetically engineered, antibiotic and vaccine resistant strains of Bacillus anthracis is fueling hypothesis-driven research and global techniques--including genomics, proteomics and transposon site hybridization--to facilitate the discovery of novel vaccine targets. This review highlights historical achievements and new developments in anthrax vaccine research.  相似文献   
4.
Summary In the feline gastrointestinal tract, the neuropeptides, substance P, VIP and PHI were investigated by specific radioimmunoassays and immunocytochemistry. The concentrations of all 3 peptides and the level of peptidergic innervation were significantly less in the anal sphincter than elsewhere, whereas no significant differences were seen between other sphincter and non-sphincter regions.  相似文献   
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Acrylamide from Maillard reaction products   总被引:75,自引:0,他引:75  
Stadler RH  Blank I  Varga N  Robert F  Hau J  Guy PA  Robert MC  Riediker S 《Nature》2002,419(6906):449-450
The discovery of the adventitious formation of the potential cancer-causing agent acrylamide in a variety of foods during cooking has raised much concern, but the chemical mechanism(s) governing its production are unclear. Here we show that acrylamide can be released by the thermal treatment of certain amino acids (asparagine, for example), particularly in combination with reducing sugars, and of early Maillard reaction products (N-glycosides). Our findings indicate that the Maillard-driven generation of flavour and colour in thermally processed foods can -- under particular conditions -- be linked to the formation of acrylamide.  相似文献   
7.
Neuropeptides were first localized in the human spinal cord by immunocytochemistry and substance P has been shown, by the same method, to be reduced ipsilaterally in the dorsal horn after limb amputation and bilaterally in the Riley-Day syndrome. Several neuropeptides increasingly fulfil the criteria to establish them as neurotransmitters or neuromodulators, and they may also have trophic actions in the spinal cord. Using radioimmunoassay and immunocytochemistry, we present here for the first time a quantitative regional distribution and localization of vasoactive intestinal polypeptide (VIP), substance P, somatostatin, bombesin and cholecystokinin (CCK-8) in normal postmortem human spinal cord. A comparison of the distribution of these peptides reveals an exceptional pattern for VIP, with relatively much higher levels in the lumbosacral region. Immunocytochemical analysis shows a distinctive distribution of VIP-containing fibres and terminals at the lumbosacral segments. This VIP-containing system may have an important role in the spinal control of urogenital function in man.  相似文献   
8.
Genetic selection for reproductive photoresponsiveness in deer mice   总被引:2,自引:0,他引:2  
C Desjardins  F H Bronson  J L Blank 《Nature》1986,322(6075):172-173
Seasonal breeding is common in mammals, particularly in habitats outside the tropics. Climate and availability of food are the ultimate factors that usually dictate the optimal time of year for a mammal to breed; however, day length (photoperiod) often serves as the proximal cue to signal the onset or cessation of seasonal reproduction. Some individuals in some populations of deer mice are reproductively responsive to photoperiod, while other individuals in the same population are not. As shown here, selection can dramatically alter the frequency of photoresponsiveness in a laboratory population in only two generations. To our knowledge this is the first demonstration of selection for reproductive photoresponsiveness in any mammal. By implication, some wild populations of deer mice must use multiple, genetic-based reproductive strategies, and the degree to which each such strategy is exhibited must be subject to rapid change in response to both seasonally and momentarily changing climatic and dietary conditions.  相似文献   
9.
The phase of the macroscopic electron-pair wavefunction in a superconductor can vary only by multiples of 2pi when going around a closed contour. This results in quantization of magnetic flux, one of the most striking demonstrations of quantum phase coherence in superconductors. By using superconductors with unconventional pairing symmetry, or by incorporating pi-Josephson junctions, a phase shift of pi can be introduced in such loops. Under appropriate conditions, this phase shift results in doubly degenerate time-reversed ground states, which are characterized by the spontaneous generation of half quanta of magnetic flux, with magnitude 1/2 Phi(0)(Phi(0) = h/2e = 2.07 x 10(-15) Wb) (ref. 7). Until now, it has only been possible to generate individual half flux quanta. Here we report the realization of large-scale coupled pi-loop arrays based on YBa2Cu3O7-Au-Nb Josephson contacts. Scanning SQUID (superconducting quantum interference device) microscopy has been used to study the ordering of half flux quanta in these structures. The possibility of manipulating the polarities of individual half flux quanta is also demonstrated. These pi-loop arrays are of interest as model systems for studying magnetic phenomena--including frustration effects--in Ising antiferromagnets. Furthermore, studies of coupled pi-loops can be useful for designing quantum computers based on flux-qubits with viable quantum error correction capabilities.  相似文献   
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