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31.
Theoretical studies on animal orientation. I. Methodological appraisal of classifications 总被引:1,自引:0,他引:1
Research on animal orientation shows a persistent lack of integration. Theories entertained in different “schools” are couched in incommensurable terms. The underlying definitions mostly do not satisfy elementary canons of methodology, and this results in a confusion of empirical and conceptual problems. Application of basic methodology shows that current classifications of orientation patterns are logically incomplete.Moreover, allegedly distinct kinds of orientation wrongly show logical dependencies resulting from poor definitions. Reference to physiological mechanisms, beyond stimuli and responses, must be omitted from definitions for orientation patterns. Likewise, orientation must not be made functional (adaptive) by definition. Vagueness is to some extent unavoidable in general theories. 相似文献
32.
CEREBRAL METABOLIC AND VASCULAR EFFECTS OF BARBITURATE THERAPY FOLLOWING COMPLETE GLOBAL ISCHEMIA 总被引:6,自引:5,他引:1
Complete global cerebral ischemia was induced in dogs by temporary ligation of the ascending aorta for 10min. Prior to the ischemic period, half of the animals were given pentobarbital 30-38 mg/kg, a maneuver previously reported to prevent or attenuate cerebral damage in this same model. Cerebral blood flow (CBF) and cerebral metabolic rate (CMRO2) were followed from prior to the ischemic period to 6 h post-ischemia. At varying time intervals following ischemia, brain biopsies were obtained and analyzed for cerebral metabolites to determine the cerebral energy state. Only a few differences were observed between pentobarbital-treated and untreated animals. Post-ischemic CMRO2, stabilized at a significantly lower level in treated than in untreated animals. However, CBF was proportionately lower and thus O2 delivery relative to O2 needs in the two groups was comparable. Also in both groups, the CBF and CMRO2 stabilized at levels significantly below pre-ischemia controls. Cerebral energy stores in both groups were depleted after 10min of ischemia but were restored to near normal within 4min post-ischemia. Total restoration of the adenine nucleotide pool and ATP were delayed as was the return of brain lactate to normal. A 10min period of post-ischemic hyperemia was observed in all animals and in the initial 4min post-ischemia CMRO2 was also increased. The latter is probably accounted for by the O2 needs for restoration of cerebral energy and O2 stores. We conclude that cerebral protection as provided by barbiturates following complete global ischemia cannot be accounted for by any measurable effect on CBF, CMRO2, or the cerebral energy stores during the initial 6 h post-ischemia. 相似文献
33.
球体蛛在我国首次被发现,本文记述了产于我国海南的纳尔蛛属一新种,定名为华纳尔蛛Wendilgarda sinensis sp. nov.,模式标本保存在河北教育学院生物系。 相似文献
34.
本文记述我国皿蛛科一新纪录属:前延首蛛届Archaraeoncus Tanasevitch 1987,并对天山前延首蛛A.tianshanicus(Hu et Wu,1989)n.comb.重新作了描述,本种的雌蛛系首次发现。本文还对Araeoncus tianschanica Hu et Wu 1989原学名命名的原始拚缀作了改正。文中测量数据均以mm为单位。 相似文献
35.
本文记述采自新疆的皿蛛科蜘蛛一新届——颚齿蛛属Maxillodens gen.nov.及其一新种——鞭状颚齿蛛M.flageuatus sp.nov。 相似文献
36.
37.
Immunohistochemical identification of tubular segments in percutaneous renal biopsies 总被引:1,自引:0,他引:1
Summary To identify the renal cortical tubular segments involved in tubulo-interstitial disease in formalin-fixed, paraffin-embedded percutaneous kidney biopsies, we developed multiple immunolabeling protocols using segment-specific tubular markers. The present study of biopsies from patients with minimal change or thin basement membrane nephropathy provides a baseline for interpretation of histopathology. Proximal tubules were stained either by the PAS reaction or by the biotinylated Phaseolus vulgaris erythroagglutinin (PHA-E)-streptavidin-gold-silver system (brush borders black). The anti-Tamm-Horsfall (THP) antibody-immunoperoxidase (aminoethylcarbazole, AEC-IPO), and anti-epidermal cytokeratins (ECK) antibodies-immunoalkaline-Fast Blue BB methods marked the distal straight tubules and the cortical collecting system red-brown and blue, respectively. When these immunolabelings were combined, the coapplication of AEC-PO-labeled peanut agglutinin (PNA) or anti-epithelial membrane antigen antibody-AEC-IPO technique (both are markers for distal nephron) visualized the apical membranes of distal convoluted tubules. In the protocol PHA-E + PNA + THP + ECK, the tubular basement membranes were outlined by the anti-laminin antibody-AEC-IPO staining, carried out simultaneously. The protocol PNA + THP + ECK + PAS was found to be a quite appropriate multiple immunolabeling method for the tubules, and is recommended for use as a tool in the study of tubulo-interstitial diseases.Abbreviations PAS
periodic acid-Schiff reaction
- PHAE
Phaseolus vulgaris erythroagglutinin
- PNA
Peanut agglutinin
- EMA
epithelial membrane antigen
- THP
Tamm-Horsfall glycoprotein
- ECK
epidermal cytokeratins
- PO
peroxidase
- Biot-PHA-E
biotinylated PHA-E
- APAAP
complexes of alkaline phosphatase and mouse monoclonal anti-alkaline phosphatase
- SWARI
swine anti-rabbit immunoglobulins
- FCS
fetal calf serum
- TBS
Tris-buffered saline
- AEC
aminoethylcarbazole
- DAB
diaminobenzidine
- FBBB
Fast Blue BB
- IA
immunoalkaline
- GL
glomerulus
- PT
proximal tubule
- DST
distal straight tubule
- DCT
distal convoluted tubule
- CCS
cortical collecting system
- CT
connecting tubule
- CD
collecting duct 相似文献
38.
The gene for the purine salvage enzyme hypoxanthine phosphoribosyltransferase (HPRT) is expressed at a low level in many cells. As is the case with several other “housekeeping genes,” thorough studies of hprt gene regulation have been hampered by the low levels of its mRNA. We have used RNA/RNA hybridization in solution to determine the concentration of hprt-RNA in human cells. The sensitivity and specificity of the method have been validated, and it is shown that hprt-RNA can be accurately determined at a level of a few mRNA molecules per cell. As expected for a housekeeping gene, low and relatively constant hprt-RNA levels (0.3–0.8 pg/μg DNA) were found in primary cultures of normal amnion cells and fibroblasts, EBV-transformed lymphoblastoid cell lines, neuroblastoma, glioblastoma, and melanoma cell cultures. While resting lymphocytes were found to contain very low amounts of hprt-RNA, lymphocytes stimulated with phytohemagglutinin (PHA) showed a 10-fold increase to about 0.8–1.2 pg/μg DNA, which corresponds to 6–10 hprt-RNA molecules per cell. The level started to increase about 20 h after PHA stimulation, 5–10 h before the onset of DNA synthesis, and a steady-state level was reached after 2–3 days in culture. In PHA-stimulated lymphocytes from two brothers with inherited HPRT deficiency (LeschNyhans syndrome), the hprt-RNA level in PHA-stimulated lymphocytes was only about 25% of that in normal subjects. In T-cells selected for HPRT deficiency by growth in 6-thioguanine medium, the levels of hprt-RNA were either normal or very low, which probably reflects the different nature of the mutations involved. These results demonstrate the sensitivity of this method for determinations of low levels of RNA and clearly show induction of hprt-RNA after mitogenic stimulation of human lymphocytes. 相似文献
39.
Wim J. van der Steen 《Acta biotheoretica》1990,38(1):23-36
Philosophical theories about reduction and integration in science are at variance with what is happenign in science. A realistic approach to science show that possibilities for reduction and integration are limited. The classical ideal of a unified science has since long been rejected in philosophy. But the current emphasis on interdisciplinary integration in philosophy and in science shows that it survives in a different guise. It is necessary to redress the balance, specifically in biology. Methodological analysis shows that many of the grand interdisciplinary theories involving biology actually represent pseudo-integration covered up by inappropriate, overgeneral concepts. Integrationism is not bad, but it must be kept within reasonable bounds. If the present analysis is appropriate, there will have to be fundamental changes in research strategy both in science and in the philosophy of science. 相似文献
40.
Erik Steen Hansen Jens Knudsen 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》1982,721(4):418-424
Heat production, free fatty acid and glycerol release from white adipose tissue fat pads from obese (ob/ob) mice and their lean littermates are determined. Heat production was significantly lower in obese mice compared to lean mice when expressed on wet weight basis but not when expressed on DNA basis. Noradrenaline significantly increased the heat production in fat pads from both groups of animals. However, the increase in heat production due to noradrenaline addition in fat pads from lean mice was significantly higher than in fat pads from obese mice. The release of free fatty acids and glycerol before incubation with noradrenaline was similar from fat pads from both groups of animals. Addition of noradrenaline to the fat pads increased the release of free fatty acids and glycerol in both groups of animals, but the increase was significantly larger from fat pads from lean mice. In the absence of noradrenaline the free fatty acid/glycerol ratio (mol/mol) in the effluent was 7.9:1 and 4.8:1 for lean mice and obese mice, respectively. In the presence of noradrenaline the ratio decreased to 3:1 for both groups of animals. 相似文献