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61.
The 11 beta-hydroxysteroid dehydrogenase (11 beta-HSD) activity of the kidney prevents access of cortisol or corticosterone to the renal mineralocorticoid receptor. Reduction of 11 beta-HSD activity by nutritional, hormonal, or pharmacologic factors might enhance the mineralocorticoid effect of these corticosteroids, thus causing sodium retention. To test this concept, we studied the effect on 11 beta-HSD activity of several antinatriuretic factors given orally to rats or exposed in vitro to rat renal tissue. Renal 11 beta-HSD activity was higher in fasted than fed rats (P < .05). Glucose, ethanol, and Toradol (Syntex Laboratories, Palo Alto, CA) given orally to fasted rats all reduced renal 11 beta-HSD activity by 20% to 40% (P < .05-.005) to levels similar to those observed in fed animals. Incubation of renal tissue from fasted rats with physiologic concentrations of insulin, ethanol, and Toradol also reduced 11 beta-HSD activity by 20% to 40% (P < .05-.01). These findings are consistent with the hypothesis that the antinatriuretic actions of these stimuli are due in part to alteration of renal 11 beta-HSD leading to greater mineralocorticoid effects in kidney. 相似文献
62.
The role of clinical pharmacology in improving the prevention and treatment of malaria is reviewed. A series of general and specific issues is discussed, concentrating on risk-benefit and cost-effectiveness. The techniques of clinical pharmacokinetics play an important role in the optimal use of drugs and this is illustrated by studies on quinine and proguanil. In discussing amodiaquine toxicity, the role of the pharmacologist and the chemist in designing out drug toxicity lends hope for producing a new generation of antimalarial drugs. 相似文献
63.
SJ Geier PA Algate K Carlberg D Flowers C Friedman B Trask LR Rohrschneider 《Canadian Metallurgical Quarterly》1997,89(6):1876-1885
The macrophage colony-stimulating factor receptor and several other hematopoietic growth factor receptors induce the tyrosine phosphorylation of a 145- to 150-kD protein in murine cells. We have previously cloned a cDNA for the murine 150-kD protein, SHIP, and found that it encodes a unique signaling intermediate that binds the SHC PTB domain through at least one tyrosine phosphorylated (NPXY) site in the carboxyl-terminal region. SHIP also contains several potential SH3 domain-binding sites, an SH2 domain for binding other tyrosine phosphorylated proteins, and an enzymatic activity that removes the phosphate from the 5 position of phosphatidylinositol 3,4,5-phosphate or from inositol 1,3,4,5-phosphate. SHIP has a negative effect on cell growth and therefore loss or modification may have profound effects on hematopoietic cell development. In this study, we have cloned a cDNA for human SHIP and examined mRNA and protein expression of SHIP and related species in bone marrow and blood cells. Flow cytometry indicates that at least 74% of immature CD34+ cells express SHIP cross-reacting protein species, whereas within the more mature population of CD33+ cells, only 10% of cells have similar expression. The majority of T cells react positively with the anti-SHIP antibodies, but significantly fewer B cells are positive. Immunoblotting detects up to seven different cross-reacting SHIP species, with peripheral blood mononuclear cells exhibiting primarily a 100-kD protein and a CD34+ acute myeloblastic leukemia expressing mainly 130-kD and 145-kD forms of SHIP. Overall, these results indicate that there is an enormous diversity in the size of SHIP or SHIP-related mRNA and protein species. Furthermore, the expression of these protein species changes according to both the developmental stage and differentiated lineage of the mature blood cell. 相似文献
64.
Immunoglobulin A levels in southern elephant seal (Mirounga leonina) milk during the suckling period
ME Marquez NH Slobodianik PA Ronayne de Ferrer AR Carlini DF Vergani GA Daneri 《Canadian Metallurgical Quarterly》1995,112(3):569-572
Immunoglobulin A (IgA) levels in milk samples from southern elephant seals at King George Island, Antarctica are reported. IgA levels were determined throughout the suckling period (approximately 23 days). The IgA concentration in southern elephant seal milk was lower than in other mammals and, unlike most mammalian milk, was not high during early lactation. There was not a definite pattern in IgA levels, which fluctuated within narrow limits throughout the suckling period (mean +/- SD, 30.81 +/- 6.38 mg IgA/100 g milk). If IgG was present, its level was too low to be detected by the method used. This is the first evidence in Southern elephant seal of the possibility of transmission of passive immunity after birth involving secretion of IgA in the milk. 相似文献
65.
Increased activity of the Na(+)-H+ exchanger (NHE-1 isoform) has been observed in cells and tissues from hypertensive humans and animals, including the spontaneously hypertensive rat (SHR). No mutation in NHE-1 DNA sequence or alteration in NHE-1 mRNA and protein expression has been demonstrated in hypertension, indicating that alterations in proteins that regulate NHE-1 activity are responsible for increased activity. The recent finding that NHE-1 phosphorylation in SHR vascular smooth muscle cells (VSMCs) was greater than in Wistar-Kyoto rat (WKY) VSMCs suggested that NHE-1 kinases may represent an abnormal regulatory pathway present in hypertension. To define NHE-1 kinases altered in the hypertensive phenotype. We measured NHE-1 kinase activity by an in-gel-kinase assay using a recombinant glutathione S-transferase NHE-1 fusion protein as a substrate. At least 7 NHE-1 kinases (42 to 90 kD) were present in VSMCs. We studied a 90-kD kinase because it was the major NHE-1 kinase and exhibited differences between SHR and WKY. Comparison of 90-kD kinase activity revealed that SHR VSMCs had increased activity in growth-arrested cells and in cells stimulated by angiotensin II (100 nmol/L for 5 minutes). Activation of the 90-kD kinase by angiotensin II was Ca2+ dependent, PKC independent, and partially dependent on the mitogen-activated protein kinase pathway. These findings indicate that increased activity of a 90-kD NHE-1 kinase is a characteristic of SHR VSMCs in culture and suggest that alterations in the 90-kD NHE-1 kinase and/or proteins that regulate its activity may be a pathogenic component in hypertension in the SHR. 相似文献
66.
H Thormar G Georgsson PA Pálsson J Balzarini L Naesens S Torsteinsdóttir E De Clercq 《Canadian Metallurgical Quarterly》1995,92(8):3283-3287
The acyclic nucleoside phosphonate analog 9-(2-phosphonylmethoxyethyl)adenine (PMEA) was recently found to be effective as an inhibitor of visna virus replication and cytopathic effect in sheep choroid plexus cultures. To study whether PMEA also affects visna virus infection in sheep, two groups of four lambs each were inoculated intracerebrally with 10(6.3) TCID50 of visna virus strain KV1772 and treated subcutaneously three times a week with PMEA at 10 and 25 mg/kg, respectively. The treatment was begun on the day of virus inoculation and continued for 6 weeks. A group of four lambs were infected in the same way but were not treated. The lambs were bled weekly or biweekly and the leukocytes were tested for virus. At 7 weeks after infection, the animals were sacrificed, and cerebrospinal fluid (CSF) and samples of tissue from various areas of the brain and from lungs, spleen, and lymph nodes were collected for isolation of virus and for histopathologic examination. The PMEA treatment had a striking effect on visna virus infection, which was similar for both doses of the drug. Thus, the frequency of virus isolations was much lower in PMEA-treated than in untreated lambs. The difference was particularly pronounced in the blood, CSF, and brain tissue. Furthermore, CSF cell counts were much lower and inflammatory lesions in the brain were much less severe in the treated lambs than in the untreated controls. The results indicate that PMEA inhibits the propagation and spread of visna virus in infected lambs and prevents brain lesions, at least during early infection. The drug caused no noticeable side effects during the 6 weeks of treatment. 相似文献
67.
BACKGROUND: Desflurane (difluoromethyl 1-fluoro 2,2,2-trifluoroethyl ether) is a new inhalational anesthetic currently under investigation for use in humans. Recently, the authors showed that desflurane is a trigger of malignant hyperthermia (MH) in susceptible swine. To date, there has been no in vivo comparison of the relative ability of inhalational anesthetics to trigger MH. The effects of desflurane, isoflurane, and halothane on six MH-susceptible purebred and six MH-susceptible mixed-bred Pietrain swine were examined. METHODS: The animals were exposed to 1 MAC and 2 MAC (if MH was not triggered after 1 MAC hour) doses of each of the three volatile anesthetics in random sequence at 7-10-day intervals and changes in end-tidal CO2, arterial blood gases, serum lactate, core and muscle temperature, blood pressure, and heart rate were measured. RESULTS: There was a statistical difference between anesthetics in the time required to trigger MH; halothane exposure resulted in the fastest onset of an MH episode (20 +/- 5 min), compared with isoflurane (48 +/- 24 min) and desflurane (65 +/- 28 min), both of which required significantly longer exposures. There was no statistical difference between the MH purebred and mixed-bred swine in the time required to trigger MH (defined as a PaCO2 of 70 mmHg) with a given agent, and time to triggering was also independent of the order of exposure to the three anesthetics. Malignant hyperthermia susceptibility was confirmed in ten surviving animals, by both in vivo succinylcholine challenge and in vitro contracture testing. CONCLUSIONS: Although all three volatile anesthetics triggered MH, exposure to halothane resulted in significantly shorter times to MH triggering when compared with desflurane and isoflurane. 相似文献
68.
69.
70.
A. N. Palagushkin S. A. Prokopenko A. P. Sergeev A. N. Arlamenkov 《Optical Memory & Neural Networks》2007,16(4):288-294
The results of experimental definition of optical parameters of silver nanolayers by the method of surface plasmon resonance
(SPR) are described. The goniometric installation for measurement of angular dependences of reflection of light by layered
nanosructures at the attenuated internal reflection (angular spectrum of reflection) is designed. Calculation of optical parameters
of nanolayers is executed taking into account the form of a curve of tin angular spectrum of reflection.
The text was submitted by the authors in English. 相似文献