The activity of prostaglandins (PG) in producing vascular permeability was quantitated by dye extraction method in skin of anaesthetized rabbits. PGE1 and PGE2 (0.01–10 μg) produced increase in vascular permeability. Activity was approximately equal to that of histamine (Hist) and 1/20 of that of bradykinin (BK) on a weight basis. The activity of PGF1 and PGF2 was only 1/20 of that of PGE1 or PGE2.
In spite of the relatively low potency of PGE1 and PGE2 in the rabbit, near threshold doses (0.1 or 1 μg) of PGE2 could potentiate permeability responses to bradykinin (0.1 μg) by 10 or 100-fold, respectively. Equivalent doses (0.1 or 1 μg) of histamine could not potentiate the bradykinin responses. Arachidonic acid (AA) at 1 μg, produced a 10-fold potentiation in the permeability response to bradykinin (0.1 μg). Pretreatment of the rabbits with indomethacin (20 mg/kg, i.p.) reduced the responses of BK (0.1 μg) + AA (1 μg) down to a similar magnitude of those seen with bradykinin alone. However, indomethacin did not block responses to either, BK alone, BK + PGE2, or BK + Hist. Various doses (1, 10, 100 and 300 μg) of arachidonic acid alone also produced increase in cutaneous vascular permeability, although its potency was only 1/3–1/8 of that of PGE2. This activity of arachidonic acid was attributed in part to its bioconversion to PGE2, since its activity was significantly reduced by the prostaglandin antagonist, diphloretin phosphate (DPP) (60 mg/kg, i.v.) and by indomethacin (20 mg/kg, i.p.), which blocks conversion of arachidonic acid to prostaglandins. Arachidonic acid may owe some of its permeability increaseing effects to histamine release, since its effects were also reduced by the anti-histamine, pyrilamine (2.5 mg/kg, i.v.). 相似文献
The activity of prostaglandins (PG) in producing vascular permeability was quantitated by dye extraction method in skin of anaesthetized rabbits. PGE1 and PGE2 (0.01–10 μg) produced increase in vascular permeability. Activity was approximately equal to that of histamine (Hist) and of that of bradykinin (BK) on a weight basis. The activity of PGF1α and PGF2α was only of that of PGE1 or PGE2.In spite of the relatively low potency of PGE1 and PGE2 in the rabbit, near threshold doses (0.1 or 1 μg) of PGE2 could potentiate permeability responses to bradykinin (0.1 μg) by 10 or 100-fold, respectively. Equivalent doses (0.1 or 1 μg) of histamine could not potentiate the bradykinin responses. Arachidonic acid (AA) at 1 μg, produced a 10-fold potentiation in the permeability response to bradykinin (0.1 μg). Pretreatment of the rabbits with indomethacin (20 mg/kg, i.p.) reduced the responses of BK (0.1 μg) + AA (1 μg) down to a similar magnitude of those seen with bradykinin alone. However, indomethacin did not block responses to either, BK alone, BK + PGE2, or BK + Hist. Various doses (1, 10, 100 and 300 μg) of arachidonic acid alone also produced increase in cutaneous vascular permeability, although its potency was only – of that of PGE2. This activity of arachidonic acid was attributed in part to its bioconversion to PGE2, since its activity was significantly reduced by the prostaglandin antagonist, diphloretin phosphate (DPP) (60 mg/kg, i.v.) and by indomethacin (20 mg/kg, i.p.), which blocks conversion of arachidonic acid to prostaglandins. Arachidonic acid may owe some of its permeability increaseing effects to histamine release, since its effects were also reduced by the antihistamine, pyrilamine (2.5 mg/kg, i.v.). 相似文献
The thermophilic blue-green alga (cyanobacterium), Mastigocladuslaminosus isolated from a hot spring, evolved hydrogen gas undernitrogen-starved conditions in light when algal cells were grownin a nitrate-free medium. Cells grown in a nitrate-medium evolvedno detectable hydrogen gas in light. The optimal temperatureand pH for hydrogen evolution were 4449?C and 7.07.5.High activity of hydrogen evolution. 1.6 ml H2/mg chl.hr, wasinduced when algal cells grown in the nitrate medium were activelyforming heterocysts in the nitrate-free medium in air. Hydrogenevolution in light was depressed by nitrogen gas and inhibitedby salicylaldoxime or DNP. This hydrogen evolution by M. laminosusis attributed to the action of nitrogenase. (Received June 20, 1979; ) 相似文献
The interaction of poly-5-bromouridylic acid [poly(BU)] with adenosine and 9-methyladenine was studied by equilibrium dialysis, optical melting, and microcalorimetry. The stacking free energy, ω, was estimated as ?17.6 kJ/mol for adenosine·2poly(BU) and ?18.8 kJ/mol for 9-methyladenine·2poly(BU) from the binding isotherms constructed from equilibrium dialysis results. The binding isotherms constructed from a series of melting curves also gave ω values for adenosine·2poly(BU). The thermal stability of the complex depends on monomer concentration, and the partial molar enthalpies of the complex formation at the midpoint of the transition were evaluated from the Tm coefficients as a function of free monomer concentration. The values of ?92.0 and ?90.4 kJ/mol were obtained for adenosine·2poly(BU) and 9-methyladenine·2poly(BU) in 0.4M NaCl–0.02M Na-cacodylate–5 × 10?4M EDTA (pH 7.0), respectively. Microcalorimetric measurements provided lower integral heats of reaction values for these complexes, i.e., ?73.2 kJ/mol for adenosine·2poly(BU) and ?71.5 kJ/mol for 9-methyladenine·2poly(BU). A comparison with a polyribouridylic acid system provided a quantitative understanding of a stabilization by bromination in terms of thermodynamic parameters. 相似文献
A new thermostable hemolysin (delta-VPH) gene was cloned from a Kanagawa-negative Vibrio parahaemolyticus strain into vector pBR322 in Escherichia coli K12. The nucleotide and amino acid sequences had no homology with those of the thermostable direct hemolysin (TDH) which causes the Kanagawa phenomenon, and of the thermolabile hemolysin (TLH) of V. parahaemolyticus. The gene was present in all V. parahaemolyticus strains tested and also in one strain of V. damsela. 相似文献
We have established a novel feeder- and recombinant cytokine-free culture system for the maintenance of primate embryonic stem (ES) cells along with a feeder-free hematopoietic differentiation protocol for high efficiency CD45-positive cell production. In our system, cynomolgus monkey ES cells were properly maintained in an undifferentiated state with high immature marker expressions and teratoma-producing activities. Embryoid bodies (EBs) were generated in the presence of serum and cytokine cocktail and subjected to attachment culture on gelatin-coated plates. After about 2 weeks, a sac-like structure filled with abundant round cells emerged at the center of flattened EB. Then total cells were collected and transferred onto new gelatin-coated plates, where cells were firmly attached and actively proliferated to confluence. After another few days culture, abundant floating cells were detected in the culture supernatant. These cells expressed high levels of CD45 (>90%), while adherent cells expressed low levels of CD45 (<10%). The former consisted of various differentiated stages of myeloid cells from immature myeloblasts to mature polymorphonuclear neutrophils and macrophages. Although the percentages of neutrophils varied between 10 to 20 depending on experiments, their mature phenotype was reproducibly confirmed by specific staining and functional assays. Our protocol provides the minimum essence for primate ES cell maintenance and hematopoietic differentiation that is beneficial from economical and clinical points of view. 相似文献
Objective: To examine the association of BMI with functional status and self‐rated health among US adults and how the association differs by age and sex. Methods and Procedures: All analyses are based on the National Health Interview Survey (NHIS), 1997–2005, a yearly, representative study of the US household population. We pooled all survey years and fitted logistic regression for the two sexes and three age strata (ages 18–44, 45–64, and ≥65). Results: Our study found that although underweight and severe obesity are consistently associated with increased disability and poorer health status, overweight and moderate obesity show associations that vary considerably by age and sex. For men, the adjusted odds ratios (ORs) for disability and poor/fair self‐rated health tended to be lowest among overweight persons, especially for ages ≥45. Among men with moderate obesity, the risk of disability was elevated for ages 18–44 but lower for ages ≥65. For women, the adjusted ORs for disability and poor/fair self‐rated health tended to be lowest among normal‐weight persons, particularly for ages ≤45. Compared to normal‐weight counterparts, overweight women aged ≥65 had a lower risk of disability but a somewhat elevated risk of poor/fair self‐rated health. Discussion: The results suggest that the association of BMI with functional status and self‐rated health varies significantly across ages and sexes. The variations in the association of BMI with functional status and self‐rated health suggest that a single “ideal body weight category” may not be appropriate for all persons or all health outcomes. 相似文献
A number of factors influence the development of tolerance, including the nature, concentration and mode of antigen presentation
to the immune system, as well as the age of the host. The studies were conducted to determine whether immunizing pregnant
mice with liposome-encapsulated DNA vaccines had an effect on the immune status of their offspring. Two different plasmids
(encoding antigens from HIV-1 and influenza virus) were administered intravenously to pregnant mice. At 9.5 days post conception
with cationic liposomes, injected plasmid was present in the tissues of the fetus, consistent with trans-placental transfer.
When the offspring of vaccinated dams were immunized with DNA vaccine, they mounted stronger antigen-specific immune responses
than controls and were protected against challenge by homologous influenza virus after vaccination. Moreover, such immune
responses were strong in the offspring of mothers injected with DNA plasmid 9.5 days after coitus. These results suggest that
DNA vaccinated mothers confer the antigen-specific immunity to their progeny. Here we describe the methods in detail as they
relate to our previously published work.
Published: April 23, 2002 相似文献
In order to increase production of a useful protein by the chloroplast transformation technique, it seems to be necessary to determine the upper limit for the accumulation of a biologically active foreign protein in chloroplasts and then improve photosynthetic capacity and plant productivity. Here we show that the stromal fractions of tobacco chloroplasts could accommodate an additional 200-260 mg ml(-1) of green fluorescent protein in the stroma without any inhibition of gas exchange under various light intensity and growth conditions. The minimum amount of fructose-1,6-/sedoheptulose-1,7-bisphosphatase (FBP/SBPase) limiting photosynthesis was then calculated. Analyses of the photosynthetic parameters and the metabolites of transformants into which FBP/SBPase was introduced with various types of promoter (PpsbA, Prrn, Prps2 and Prps12) indicated that a 2- to 3-fold increase in levels of FBPase and SBPase activity is sufficient to increase the final amount of dry matter by up to 1.8-fold relative to the wild-type plants. Their increases were equivalent to an increase of <1 mg ml(-1) of the FBP/SBPase protein in chloroplasts and were calculated to represent <1% of the protein accumulated via chloroplast transformation. Consequently, >99% of the additional 200-260 mg ml(-1) of protein expressed in the chloroplasts could be used for the production of useful proteins in the photosynthesis-elevated transplastomic plants having FBP/SBPase. 相似文献
We have previously reported that highly oligomeric procyanidins (HOPC) purified from Jatoba, a South American herb, ameliorated experimental autoimmune encephalomyelitis (EAE) in mice. In this present study, we report that symptoms of arthritis were also significantly reduced by administering the Jatoba extract, when compared with the vehicle-alone-treated control. Interferon-gamma (IFN-gamma) production by the splenocytes from mice injected with procyanidins was also dramatically decreased. The oral administration of purified HOPC was significantly more effective in disease prevention than the ethanol (EtOH) extract of Jatoba. Green tea polyphenol administration, however, surprisingly facilitated disease development. Observation of the joint histopathology on whole paws derived from the HOPC-treated mice showed complete abrogation of collagen induced arthritis (CIA), a characteristic of chronic inflammation in the synovial tissue. These results demonstrate that HOPC administration had an inhibitory effect on both chronic arthritis and EAE and that the oral administration of HOPC exerted its effect after the induction of secondary immunity. 相似文献