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排序方式: 共有61条查询结果,搜索用时 15 毫秒
31.
Tripti Gaur Rajini Mudhasani Jennifer L. Colby Barbara E. Kream Janet L. Stein Stephen N. Jones 《Developmental biology》2010,340(1):10-9868
MicroRNA attenuation of protein translation has emerged as an important regulator of mesenchymal cell differentiation into the osteoblast lineage. A compelling question is the extent to which miR biogenesis is obligatory for bone formation. Here we show conditional deletion of the Dicer enzyme in osteoprogenitors by Col1a1-Cre compromised fetal survival after E14.5. A mechanism was associated with the post-commitment stage of osteoblastogenesis, demonstrated by impaired ECM mineralization and reduced expression of mature osteoblast markers during differentiation of mesenchymal cells of ex vivo deleted Dicerc/c. In contrast, in vivo excision of Dicer by Osteocalcin-Cre in mature osteoblasts generated a viable mouse with a perinatal phenotype of delayed bone mineralization which was resolved by 1 month. However, a second phenotype of significantly increased bone mass developed by 2 months, which continued up to 8 months in long bones and vertebrae, but not calvariae. Cortical bone width and trabecular thickness in DicerΔoc/Δoc was twice that of Dicerc/c controls. Normal cell and tissue organization was observed. Expression of osteoblast and osteoclast markers demonstrated increased coupled activity of both cell types. We propose that Dicer generated miRs are essential for two periods of bone formation, to promote osteoblast differentiation before birth, and control bone accrual in the adult. 相似文献
32.
Recent empirical findings have contributed valuable mechanistic information in support of a regulated de novo biosynthetic pathway for chemically authentic morphine and related morphinan alkaloids within animal cells. Importantly,
we and others have established that endogenously expressed morphine represents a key regulatory molecule effecting local circuit
autocrine/paracrine cellular signaling via a novel μ3 opiate receptor coupled to constitutive nitric oxide production and release. The present report provides an integrated review
of the biochemical, pharmacological, and molecular demonstration of μ3 opiate receptors in historical linkage to the elucidation of mechanisms of endogenous morphine production by animal cells
and organ systems. Ongoing research in this exciting area provides a rare window of opportunity to firmly establish essential
biochemical linkages between dopamine, a morphine precursor, and animal biosynthetic pathways involved in morphine biosynthesis
that have been conserved throughout evolution.
Special issue article in honor of Dr. Ji-Sheng Han. 相似文献
33.
34.
Maszczynska Iwona Lipkowski Andrzej W. Carr Daniel B. Kream Richard M. 《International journal of peptide research and therapeutics》1998,5(5-6):395-398
Summary Many years preclinical and clinical anatomic, pharmacologic, and physiologic studies suggest that SP- and opioid-expressing
neurons produce opposite biological effects at the spinal level, i.e., nociception and antinociception, respectively. However,
in certain circumstances intrathecally administered SP is capable of reinforcing of spinal morphine analgesia and may therefore
function as an opioid adjuvantin vivo. The SP dose-response curve of spinally administered SP follows a bell-shaped or inverted-U configuration, permitting pharmacological
dissociation of opioid-potentiating and analgesic properties of SP from traditional hyperalgesic effects seen at significantly
higher concentrations. This analgesic effect is blocked by naloxone but unaffected by transection of the spinal cord, thus
demonstrating the lack of supraspinal modulation. The present report briefly describes both reinforcing and opposing interactions
between multiple opioid systems and substance P at the spinal level. We propose that a likely mechanism underlying SP-mediated
enhancement of opioid analgesia is the ability of SP to release endogenous opioid peptides within the local spinal cord environment. 相似文献
35.
Hiroyuki Shimonaka James E. Marchand Christopher S. Connelly Richard M. Kream 《Journal of neurochemistry》1992,59(1):81-92
This report describes the generation and biochemical characterization of a high-affinity antiserum that recognizes an epitope contained in the midportion sequence of substance P, i.e., substance P4-10. Designated A47, this reagent bound a variety of related peptide species containing the substance P4-10 sequence with apparent equipotency. A double radioimmunoassay procedure was developed that utilized A47, in combination with a traditional high-affinity COOH-terminally directed anti-substance P serum, to provide quantification of mature and immature forms of substance P in CNS tissues. Across most rat CNS areas, levels of substance P-like immunoreactivity were consistently 15% higher when monitored by analyses using A47 versus anti-substance P serum. In the dorsal root ganglia, an apparent enhancement in levels of substance P-like immunoreactivity of approximately 40%, when quantified by analyses using A47 versus anti-substance P serum, was observed; this most likely reflected the presence of an active biosynthetic pool of intermediate processing forms of substance P in this tissue. Coordinated HPLC/radioimmunoassay analyses of extracted dorsal root ganglia tissues demonstrated multiple peaks of immunoreactivity corresponding to mature substance P and to several of its precursor forms found in the normal biosynthetic pathway. Of the total recovered HPLC-fractionated immunoreactivities, that corresponding to the putative immediate precursor to substance P, i.e., substance P-glycine, was the predominant peak. In an additional series of HPLC/radioimmunoassay analyses, selective decreases in immunoreactive peaks corresponding to precursor forms of substance P were observed in dorsal root ganglia tissues from rats treated with the neurotoxic agent capsaicin. These results indicated decreased turnover of substance P as a consequence of drug treatment. Finally, initial immunohistochemical analyses employing affinity-purified A47 produced an unusual pattern of labeling characterized by well defined punctate terminal elements within the superficial aspects of the dorsal horn of the spinal cord. 相似文献
36.
Barbara E. Kream Robert D. Reynolds Joyce C. Knutson John A. Eisman Hector F. DeLuca 《Archives of biochemistry and biophysics》1976,176(2):779-787
The binding of 25-hydroxy-[26,27-3H]vitamin D3 and 1,25-dihydroxy-[26,27-3H]vitamin D3 to the cytosol of intestinal mucosa of chicks and rats has been studied by sucrose gradient analysis. The cytosol from chick mucosa showed variable binding of 1,25-dihydroxyvitamin D3 to a 3.0S macromolecule which has high affinity and low capacity for this metabolite. However, when the mucosa was washed extensively before homogenization, a 3.7S macromolecule was consistently observed which showed considerable specificity and affinity for 1,25-dihydroxyvitamin D3. Although 3.7S binders for 1,25-dihydroxyvitamin D3 could also be located in other organs, competition experiments with excess nonradioactive 1,25-dihydroxyvitamin D3 suggested that they were not identical to the 3.7S macromolecule from intestinal mucosal cytosol. As the 3.7S macromolecule was allowed to stand at 4 °C with bound 1,25-dihydroxy-[3H]vitamin D3, the 1,25-dihydroxy-[3H]vitamin D3 became increasingly resistant to displacement by non-radioactive 1,25-dihydroxyvitamin D3. The 1,25-dihydroxy-[3H]vitamin D3 remained unchanged and easily extractable with lipid solvents through this change, making unlikely the establishment of a covalent bond. Unlike the chick, mucosa from rats yielded cytosol in which no specific binding of 1,25-dihydroxy-[3H]vitamin D3 was detected. Instead, a 5-6S macromolecule which binds both 1,25-dihydroxyvitamin D3 and 25-hydroxyvitamin D3 was found. This protein which was also found in chick mucosa shows preferential binding for 25-hydroxyvitamin D3. It could be removed by washing the mucosa with buffer prior to homogenization which suggests that it may not be a cytosolic protein. Although the 3.7S protein from chick mucosa has properties consistent with its possible role as a receptor, the 5-6S macromolecule does not appear to have “receptor”-like properties. 相似文献
37.
Lawrence G. Raisz M.D. Jack Y. Vanderhoek Ph.D. Hollis A. Simmons Barbara E. Kream Ph.D. K.C. Nicolaou Ph.D. 《Prostaglandins & other lipid mediators》1979,17(6):905-914
Prostaglandin synthesis by fetal rat bones was examined by thin-layer chromatography of culture media after preincubation with labeled arachidonic acid. Cultures in rabbit complement (non-heat inactivated serum) were compared with cultures in heat-inactivated serum or cultures treated with indomethacin. The major complement-dependent products were PGE2, PGF2α and 6-keto-PGF1α, the metabolite of prostacyclin (PGI2). Since PGI2 had not been previously identified in bone its ability to stimulate bone resorption was tested. Repeated addition of PGI2 stimulated release of previously incorporated 45Ca from fetal rat long bones in both short-term and long-term cultures at concentrations of 10−5 to 10−9M. Because of the short half life of PGI2 in solution at neutral pH, we tested a sulfur analog, thiaprostacyclin (S-PGI2) which was found to be a stimulator of bone resorption at concentrations of 10−5 to 10−6M. These studies suggest that endogenous PGI2 production may play a role in bone metabolism. Since vessels produce PGI2 it is possible that PGI2 release may be responsible for the frequent association between vascular invasion and resorption of bone or calcified cartilage in physiologic remodeling and pathologic osteolysis. 相似文献
38.
López-Valenzuela BE Armenta-Bojórquez AD Hernández-Verdugo S Apodaca- Sánchez MA Samaniego-Gaxiola JA Valdez-Ortiz A 《Phyton》2019,88(1):37-46
Microbes that are beneficial to plants are used to
enhance the crop growth, yield and are alternatives to chemical
fertilizers. Trichoderma and Bacillus are the predominant plant
growth-promoting fungi and bacteria. The objective of this study
was select, characterize, and evaluate isolates of Trichoderma
spp. and Bacillus spp. native from the northern region of Sinaloa,
Mexico, and assess their effect on growth promotion in maize (Zea
mays L.). In greenhouse conditions, four Trichoderma isolates and
twenty Bacillus isolates, as well as two controls, were tested in a
completely randomized design with three replicates. We selected
the two best strains of Trichoderma and Bacillus: TB = Trichoderma
asperellum, TF = Trichoderma virens, B14 = Bacillus cereus sensu
lato and B17 = Bacillus cereus, which were evaluated in the field in
a completely randomized blocks in factorial arrangement design
with three replicates applying different rates of nitrogen fertilizer
(0, 150 kg N/ha, and 300 kg N/ha). Treatments 5 (B17 = B. cereus)
and 11 (TF = T. virens) both fertilized with 150 kg N/ha showed
similar yields and they did not reveal significant differences from
the treatments fertilized with 300 kg N/ha. This indicated that
treatment 5 (B17= B. cereus with 150 kg N/ha) and treatment
11 (TF= T. virens with 150 kg N/ha) were efficient as growth
promoters, by not showing significant differences in root volume
and dry weight of foliage. The results indicated a reduction of 50%
in the rate of nitrogen to fertilizer required for maize (Zea mays
L.) crops. These microorganisms Trichoderma and Bacillus could
be an alternative to reduce the use of chemical fertilizers in maize. 相似文献
39.
17-Carboxymethoximino derivatives of DHA (1), androsterone and etiocholanolone, as well as the 7-carboxymethoximino derivatives of 3β-hydroxy-androst-5-ene-7,17-dione and 7-keto-androst-5-ene-3β, 17β-diol have been prepared and conjugated to BSA for use in producing antisera to the corresponding C19 steroids. 相似文献
40.