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991.
A significant number of adult male patients with acquired immunodeficiency syndrome develop cerebral atrophy and progressive brain disorders such as dementia complex and neuropsychiatric problems. Upon entering the brain via activated macrophages or microglias, the human immunodeficiency type 1 virus (HIV-1) may produce cytotoxic factors such as HIV-1 envelope protein (gp 120) and protease. Owing to significant proteolysis of nonviral proteins, the protease derived from HIV-1 may be detrimental to brain cells and neurons. Our results revealed that HIV-1 protease, at nanomolar concentrations, was as potent as gp 120 in causing neurotoxicity in human neuroblastoma neurotypic SH-SY5Y cells. As shown by the Oncor ApopTag staining procedure, HIV-1 protease significantly increased the number of apoptotic cells over the serum-free controls. Moreover, HIV-1 protease-induced neurotoxicity was blocked by a selective protease inhibitor, kynostatin (KNI-272). Antioxidants such as 17-estradiol, melatonin, andS-nitrosoglutathione also prevented protease-induced neurotoxicity. These findings indicate that oxidative proteolysis may mediate HIV-1 protease-induced apoptosis and the degeneration of neurons and other brain cells. Centrally active protease inhibitors and antioxidants may play an important role in preventing cerebral atrophy and associated dementia complex caused by HIV-1. 相似文献
992.
Iva M. Tolić 《Cell cycle (Georgetown, Tex.)》2016,15(9):1169-1170
993.
Fumihiko Sugino Tokuo Ogawa Satoshi Umemura Satoru Suzuki Yasuhiro Kawamura 《European journal of applied physiology and occupational physiology》1997,75(3):252-255
The influence of the increased cerebral blood flow (CBF) induced by acetazolamide on tympanic temperature (T
ty) was examined in three healthy male volunteers and in five patients with subacute subarachnoid haemorrhage (SAH). The CBF
was estimated by means of stable xenon-enhanced computed tomography before and after the administration of acetazolamide.
The T
ty was recorded continuously in both ears using thermistor thermometers. In all subjects, CBF increased ranging from 11% to
108% after acetazolamide administration. In all the healthy subjects and in two patients with mild SAH, T
ty was higher than the oesophageal temperature (T
oes) and T
ty decreased bilaterally, ranging from 0.07 to 0.35°C as CBF increased. Three patients with severe SAH were febrile, their T
oes exceeding T
ty, and their T
ty rose by 0.30 to 0.53°C with increased CBF. These observations suggest that T
ty follows brain temperature which changes with an increase in CBF in euthermic subjects as well as in febrile subjects.
Accepted: 3 September 1996 相似文献
994.
K. A. O. Ellem Michael G. E. O’Rourke Gregory R. Johnson Gordon Parry Ihor S. Misko Christopher W. Schmidt Peter G. Parsons Scott R. Burrows Simone Cross Andrew Fell Chung-Leung Li John R. Bell Philip J. Dubois Denis J. Moss Michael F. Good Anne Kelso Lawrence K. Cohen Glenn Dranoff Richard C. Mulligan 《Cancer immunology, immunotherapy : CII》1997,44(1):10-20
The first use of granulocyte/macrophage-colony-stimulating-factor-transduced, lethally irradiated, autologous melanoma cells
as a therapeutic vaccine in a patient with rapidly progressive, widely disseminated malignant melanoma resulted in the generation
of a novel antitumour immune response associated with partial, albeit temporary, clinical benefit. An initially negative reaction
to non-transduced, autologous melanoma cells was converted to a delayed-type hypersensitivity (DTH) reaction of increasing
magnitude following successive vaccinations. While intradermal vaccine sites showed prominent dendritic cell accrual, DTH
sites revealed a striking influx of eosinophils in addition to activated/memory T lymphocytes and macrophages, recalling the
histology of challenge tumour cell rejection in immune mice. Cytotoxic T lymphocytes (CTL) reactive with autologous melanoma
cells were detectable at high frequency after vaccination, not only in limiting-dilution analysis, but also in bulk culture
without added cytokines. Clonal analysis of CTL showed a conversion from a purely CD8+ response to a high proportion of CD4+ clones following vaccination. A prominent acute-phase response manifested by a five- to tenfold increase in C-reactive protein
was observed, as was a systemic eosinophilia. Vaccination resulted in the regression of axillary lymphatic metastases, stabilisation
of pulmonary metastases, and a dramatic, reversible increase in cerebral oedema associated with multiple central nervous system
metastases; however, lesions in the adrenal glands, pancreas and spleen proved refractory. The antitumour effects and immune
response were not detectable 2 months following the last vaccination. Irradiation of the extensive cerebral metastases resulted
in rapid deterioration and death of the patient.
Received: 20 September 1996 / Accepted: 5 December 1996 相似文献
995.
In Vivo Evidence for the Link Between l- and d-Serine Metabolism in Rat Cerebral Cortex 总被引:2,自引:0,他引:2
Abstract: To obtain an insight into the metabolic pathways of endogenous d -serine in mammalian brains, we have investigated in the infant rat the effects of systemic administration of l -serine, d -serine, and related amino acids, including glycine and threonine, on the amino acid contents in the cerebral cortex. Intraperitoneal injection of l -serine induced a rapid and transient elevation of the levels of l -serine itself in the neocortex, with its peak at 3 h post injection, and a delayed and prolonged increase in d -serine contents from 1.5 h to at least 24 h thereafter. Similarly, a significant augmentation in cerebral d -serine contents was observed 6 h after intraperitoneal administration of glycine, which also elevated the cortical l -serine levels. In contrast, l -threonine injection affected the concentrations of neither d - nor l -serine in the cortex of the pups. d -Serine given systemically, in turn, increased the neocortical contents of l -serine as well as d -serine itself, but failed to alter those of glycine and l -threonine. These in vivo data suggest the possible link between metabolic pathways of d - and l -serine in the cerebral cortex of the rat. 相似文献
996.
Tomoaki Sato Yoshiko Kamata Masahiro Irifune Takashige Nishikawa 《Journal of neurochemistry》1997,68(3):1312-1318
Abstract: Nitric oxide (NO)-generating compounds (NO donors) such as sodium nitroprusside, S-nitroso-N-acetylpenicillamine, S-nitroso-l -glutathione, 3-morpholinosyndnonimine (SIN-1), (dl )-(E)-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide, and 1-hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene inhibited the Na+,K+-ATPase activity purified from porcine cerebral cortex. NO-reducing or -scavenging agents, such as superoxide dismutase or N-(dithiocarbamate)-N-methyl-d -glucamine sodium salt, l -ascorbic acid, and sulfhydryl (SH) compounds, such as dithiothreitol or the reduced form of glutathione, but not α-tocopherol, prevented the inhibition of the enzyme activity by all NO donors except sodium nitroprusside. Enzyme inhibition could also be reversed by these SH compounds, but not by superoxide dismutase, l -ascorbic acid, and α-tocopherol. 2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazolin-1-oxyl 3-oxide (PTIO), which is able to scavenge NO radicals and generate nitrogen dioxide radicals (?NO2), potentiated the inhibition of this enzyme activity induced by all NO donors (except SIN-1). PTIO did not potentiate, but rather attenuated, the SIN-1-induced inhibition. SIN-1 has been reported to release both NO and superoxide and thereby to rapidly form peroxynitrite (ONOO?). These potentiated and attenuated inhibitions of the enzyme activity induced by PTIO plus all of the NO donors except sodium nitroprusside were prevented by SH compounds, but not by superoxide dismutase, l -ascorbic acid, and α-tocopherol. These results suggest that NO donors may release NO or NO-derived products, presumably ?NO2 and ONOO?, and may inhibit the Na+,K+-ATPase activity by interacting with a SH group at the active site of the enzyme. 相似文献
997.
An Investigation of the Low Intrinsic Activity of Adenosine and Its Analogs at Low Affinity (A2) Adenosine Receptors in Rat Cerebral Cortex 总被引:8,自引:4,他引:4
The potencies and intrinsic activities of adenosine analogs for stimulating cyclic AMP accumulation in slices of rat cerebral cortex were examined. 5'-N-Ethylcarboxamidoadenosine (NECA) caused the greatest increase in cyclic AMP accumulation (19.2-fold). 2-Chloroadenosine (2-CAD) induced a similar increase, but adenosine and six other analogs caused much smaller increases. All agonists tested had similar potencies in activating this response. Inhibition of adenosine uptake with 10 microM dipyridamole did not affect the maximal response to any agonist, although the potency of adenosine was increased approximately threefold. Each analog was also able to block partially the stimulation of cyclic AMP accumulation caused by NECA. Levels of cyclic AMP accumulation in the presence of NECA plus another analog were similar to those observed when the analog alone was present, as expected for partial agonists. Furthermore, the EC50 value for R-(-)-N6(2-phenylisopropyl)adenosine in increasing cyclic AMP accumulation was similar to the KI value for inhibiting the response to NECA. The EC50 value for adenosine was substantially higher than the KI value for inhibiting the response to NECA; however, in the presence of dipyridamole, the two values were more closely correlated. The response to NECA was blocked by 8-phenyltheophylline, 1,3-diethyl-8-phenylxanthine, and 8-p-sulfophenyltheophylline, with KI values from 1 to 10 microM. The results suggest that adenosine analogs stimulate cyclic AMP accumulation in cerebral cortex through low-affinity receptors, but that some analogs only partially activate these receptors. Adenosine itself may also be a partial agonist, or its actions may be obscured by simultaneous activation of another receptor. 相似文献
998.
Species assembly and the evolution of community structure 总被引:8,自引:0,他引:8
Barry J. Fox 《Evolutionary ecology》1987,1(3):201-213
Summary In this paper I consider the evolutionary and ecological implications of an assembly rule which was derived empirically from studies on a heathland small-mammal community in south-eastern Australia. This rule has been tested successfully against 52 heathland small-mammal assemblages. Here it is shown to hold also for 80 forest assemblages of small mammals spanning a latitudinal range from 27°S to 43°S in south-eastern Australia. The observed forest communities are predicted by the rule and they deviate significantly from random assemblages. I suggest that the unique evolutionary history of the Australian fauna has made these patterns more apparent. The rule is simply stated as: There is a much higher probability that each species entering a community will be drawn from a different functional group (genus or other taxonomically related group of species with similar diets) until each group is represented, before the cycle repeats. A theoretical basis for the rule is proposed which extends the niche compression hypothesis to cover evolutionary time. Evolutionary constraints on adaptations for diet selection are greater than those operating on habitat selection. Successful tests in North America for the granivorous desert rodent guild and the mixed-forest insectivore guild support a wider application of this rule than the Australian communities from which it was derived. A speculative model is proposed in which the mechanisms involved in the operation of this rule shape the evolution of community structure. 相似文献
999.
Kōichi Andō 《Cell and tissue research》1988,251(2):345-351
Summary The overall distribution and origins of vasoactive intestinal polypeptide (VIP)-immunoreactive (IR), acetylcholinesterase (AChE)-positive and adrenergic nerves in the walls of the cerebral arteries were investigated in the bent-winged bat. VIP-IR and AChE-positive nerves innervating the bat cerebral vasculature appear to arise mainly from VIP-IR and AChE-positive cell bodies within microganglia found in the nerve bundle accompanying the sympathetic nerve bundle within the tympanic cavity. These microganglia, as well as the nerve bundle containing them, do not emit catecholamine fluorescence, suggesting that they are of the cranial parasympathetic outflow, probably the facial or glossopharyngeal one. The axons from VIP-IR and AChE-positive microganglia run intermingled with sympathetic adrenergic nerves in the same thick fiber bundles, and reach the cranial cavity through the carotid canal. In addition, some of the VIP-IR fibers innervating the vertebro-basilar system, at least the basilar artery, originate from VIP-IR nerve cells located in the wall of this artery.The supply of VIP-IR fibers to the bat major cerebral arteries is the richest among mammals that have been studied, and differs from other mammals in that it is much greater in the vertebro-basilar system than in the internal carotid system: plexuses of VIP-IR nerves are particularly dense along the walls from the posterior ramus to posterior cerebral and basilar arteries. Small pial and intracerebral arteries of the vertebro-basilar system, especially those of the posterior cerebral artery which supply most parts of the diencephalon and cerebrum, are also richly innervated by peripheral VIP-IR fibers. This pattern corresponds well with the innervation pattern of adrenergic and AChE-positive nerves. 相似文献
1000.
Wesley M. Williams Ph.D. Melvin Reichman Thomas H. McNeill 《Neurochemical research》1988,13(8):743-747
Cerebral microvessels consisting predominantly of capillaries and small arterioles (<30 m dia.) were isolated from the cerebral cortex and cerebellum of 3-month-old mice. Lipids were extracted from both microvascular and brain parenchymal fractions and the major phospholipid classes (choline phosphoglyceride, ethanolamine phosphoglyceride, inositol phosphoglyceride, serine phosphoglyceride, and sphingomyelin) separated by 2-dimensional TLC. Comparison of mol % determined by phosphate analysis of each phospholipid revealed significant differences in membrane composition of ethanolamine phosphoglyceride, inositol phosphoglyceride, and sphingomyelin between microvascular and parenchymal components of the central nervous system. Moreover, the choline phosphoglyceride/sphingomyelin mol ratio, one of three determinants of membrane fluidity, is significantly lower for microvessel membrane than for membranes of the brain parenchyma. 相似文献