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11.
Elastase-like enzymes in human neutrophils localized by ultrastructural cytochemistry 总被引:6,自引:1,他引:5
The thiol ester N-t-Boc-L-alanine-p-nitrothiophenyl ester (Boc-Ala-SNp) was synthesized and applied as an ultrastructural cytochemical substrate for intracellular elastase-like enzymes. Mature human neutrophils incubated with Boc-Ala-SNp and gold ions generate an electron-dense reaction product, gold p-nitrothiophenolate, which is found in the nuclear membrane, Golgi complex, endoplasmic reticulum, mitochondria, and granules of these cells. Enzyme activity against Boc- Ala-SNp is also observed in developing monkey bone marrow neutrophils and in other blood cells. The intracellular neutrophil enzyme activity is elastase-like because it is characterized by a slightly alkaline pH optimum and is inactivated by exposure of the cells to general and specific active site inhibitors of neutrophil elastase. This substrate appears to have important potential for use in ultrastructural studies of intracellular elastase-like enzymes. 相似文献
12.
Domestic pigeons were introduced into the Galapagos Islands in 1972 or 1973. There is a high prevalence of Trichomonas gallinae among them and some evidence of canker. Trichomonas gallinae can be found also in endemic Galapagos doves in the vicinity of Puerto Ayora on Santa Cruz Island. Doves examined on pigeon-free islands were not found infected. 相似文献
13.
A case of chromomycosis in which hyperthermia proved effective is reported. The patient was a 56-year-old male bean curd maker who, without any previous history of minor trauma, developed on the extensor side of the left upper arm an eczematous lesion that underwent gradual radial expansion. The lesion showed a well-defined, 7×10 cm infiltrated erythematous plaque with the central area healed and, at the upper and lower borders, adherent scales and crusts on the surface. Histological examination revealed granulomatous changes in the dermis, as well as sclerotic cells within giant cells and microabscesses. On culturing,Fonsecaea pedrosoi was isolated. The patient was treated with disposable chemical pocket warmers, which were secured over the lesion with a rather tight elastic bandage, so that they kept the affected area warm for 24 hours a day. After a month of such hyperthermic treatment, the erythema and infiltration had decreased considerably, and microscopic examination and culture of the crusts both yielded negative results. Examination of biopsy specimens of the lesion after the third month showed that it had cicatrized. The treatment was stopped after 4 months, and no relapse occurred. We also summarize the published results of local hyperthermic treatment of chromomycosis in Japan. 相似文献
14.
S J Getting L Gibbs A J Clark R J Flower M Perretti 《Journal of immunology (Baltimore, Md. : 1950)》1999,162(12):7446-7453
To investigate the relevance of adrenocorticotrophic hormone (ACTH) therapy in human gouty arthritis, we have tested the effect of several ACTH-related peptides in a murine model of experimental gout. Systemic treatment of mice with ACTH4-10 (MEHFRWG) (10-200 microgram s. c.) inhibited neutrophil accumulation without altering peripheral blood cell counts or circulating corticosterone levels. A similar effect was seen with alpha- and beta-melanocyte stimulating hormones (1-30 microgram s.c.). In vivo release of the chemokine KC-(detected in the lavage fluids before maximal influx of neutrophils) was significantly reduced (-50 to -60%) by ACTH4-10. Macrophage activation in vitro, determined as phagocytosis and KC release, was inhibited by ACTH and ACTH4-10 with approximate IC50 values of 30 nM and 100 microM, respectively. The melanocortin receptor type 3/4 antagonist SHU9119 prevented the inhibitory actions of ACTH4-10 both in vitro and in vivo. However, melanocortin type 3, but not type 4, receptor mRNA was detected in mouse peritoneal macrophages by RT-PCR. Therefore, we propose that activation of this receptor type by ACTH4-10 and related amino acid sequences attenuates KC release (and possibly production of other cytokines) from macrophages with consequent inhibition of the host inflammatory response, thus providing a notional anti-inflammatory mechanism for ACTH that is unrelated to stimulation of glucocorticoid release. 相似文献
15.
The compound p-mercuribenzenefulfonate was found to affect the self-association behavior of both spectrin and actin. The reagent brings about the depolymerization of F-actin, as judged from the decrease in the fluorescence of an attached pyrene label, with a second-order rate constant an order of magnitude less than that for the disruption of isolated erythrocyte cytoskeletons. Therefore, it is unlikely that the depolymerization of actin is the rate-determining step in the mercurial-dependent disruption of the erythrocyte cytoskeleton. Low reagent concentrations caused an initial rapid dissociation of spectrin tetramers at a rate comparable with that of cytoskeleton disruption. Prolonged incubation, or higher reagent concentrations, resulted in subsequent aggregation of spectrin. The reagent also prevented the interaction between spectrin and actin, presumably through its depolymerization of actin and its effects on spectrin. The early event in the disruption of isolated erythrocyte cytoskeletons by p-mercuribenzenesulfonate thus appears to be the dissociation of spectrin oligomers. Subsequent depolymerization of actin brought about by the reagent then results in total disruption of the cytoskeleton. 相似文献
16.
17.
J. Desmond Clark 《Journal of human evolution》1987,16(7-8)
Significant differences in activity-site patterning and artifact composition at Middle Pleistocene localities in Ethiopia's high plains and Afar Rift are indications of both single-episode, small-site residues from small groups and multi-purpose, multiple occupation sites from which larger, temporary groupings might be inferred. Reconstructions of palaeo-environments and geography show that large assemblages relate to relatively stable topography, such as stream channels or lake margins, while small assemblages are more common in deltaic situations of rapid sedimentation and burial in the Rift that preclude possibility of reoccupation. A model for Acheulian socio-economic behaviour within the drier African savanna, based (in part) on chimpanzee behaviour in open savanna habitats, is proposed. This takes the form of organization into relatively extensive territories, each with several more closed-vegetation core areas, of limited extent close to permanent water, surrounded by more extensive areas of drier, open savanna, regularly exploited and patrolled by small groups. Movement from one core area to another was rapid and made together as a group, to minimize danger from large predators and competition from other hominid groups. 相似文献
18.
The stimulated human neutrophil can damage a variety of target cells, and in some models, a mechanism involving secretion of myeloperoxidase and H2O2 has been demonstrated. We explored the characteristics of this cell-cell interaction by using neutrophils and our recently described liposome model target cell system. Exposure of 51Cr-labeled liposomes to phorbol myristate acetate-stimulated human neutrophils resulted in release of 25 to 30% of the radioactivity. 51Cr release was abrogated by omission of the neutrophils, the phorbol ester or halide (iodide), replacement of the phorbol by an inactive congener, or addition of azide, cyanide, or catalase. Neutrophils from patients with hereditary absence of myeloperoxidase (MPO) or a failure of H2O2 formation (chronic granulomatous disease) did not cause liposome lysis unless purified MPO or a source of H2O2, respectively, was added. These data indicate that 51Cr release from liposomes is a consequence of the secretion of MPO and H2O2, which combine with extracellular halides to form a membrane lytic system. The influence of liposome composition on injury was then examined, with a focus on physiologically relevant lipid soluble antioxidants. Liposomes containing either alpha-tocopherol (0.33 to 1.67% of molar fraction of lipid) or beta-carotene (1.67% of molar fraction of lipid) were markedly resistant to lysis by the cellfree MPO-H2O2-chloride system. When the major structural lipid phosphatidyl choline was replaced by dipalmitoyl phosphatidyl choline, a synthetic phospholipid with no oxidizable double bonds, the resultant liposomes were totally resistant to lysis by the MPO-H2O2-chloride system. The addition of iodide to this system (i.e., both chloride and iodide present) changed the pattern of protection dramatically in that alpha-tocopherol and beta-carotene were no longer protective and the resistance of dipalmitoyl phosphatidyl choline liposomes was partial rather than complete. In contrast to iodide, the addition of bromide or thiocyanate did not have a major effect on the protection by antioxidants. Finally, we demonstrated protection by alpha-tocopherol or dipalmitoyl phosphatidyl choline against liposome lysis by phorbol-activated neutrophils. These studies illustrate the use of model phospholipid membranes in the characterization of oxygen-dependent cell-mediated cytotoxicity. Activated neutrophils lyse liposome targets through a MPO-dependent mechanism. Target properties, especially the content of lipid-soluble antioxidants, have a marked influence on susceptibility to lysis.(ABSTRACT TRUNCATED AT 400 WORDS) 相似文献
19.
Photoreactions of human lens monomeric crystallins 总被引:1,自引:0,他引:1
Human lens beta s- and gamma A-crystallins exhibit very similar tryptophan fluorescence emission maxima (329 nm). gamma A isolated from infant human lenses is photo-oxidized by 300 nm irradiation and forms water-insoluble aggregates; beta s or gamma A from young human lenses form a small amount of water-soluble crosslinked species. At least part of the mechanism of photodamage by 300 nm irradiation is photogeneration of the oxidant H2O2 via the generation of O2- radical, this reaction occurs via photosensitization by the tryptophan photo-oxidation product N-formylkynurenine (N-FK) or related species. These results indicate that even though the tryptophan residues of beta s- and gamma A-crystallins are in hydrophobic (buried) microenvironments as compared to those of the alpha- and beta-crystallins, the photogeneration of N-FK is sufficient to produce O2- and H2O2. 相似文献
20.
Mary Margaret Huizinga Sara N. Bleich Mary Catherine Beach Jeanne M. Clark Lisa A. Cooper 《Obesity (Silver Spring, Md.)》2010,18(10):1932-1937
Physician perception of medication adherence may alter prescribing patterns. Perception of patients has been linked to readily observable factors, such as race and age. Obesity shares a similar stigma to these factors in society. We hypothesized that physicians would perceive patients with a higher BMI as nonadherent to medication. Data were collected from the baseline visit of a randomized clinical trial of patient–physician communication (240 patients and 40 physicians). Physician perception of patient medication adherence was measured on a Likert scale and dichotomized as fully adherent or not fully adherent. BMI was the predictor of interest. We performed Poisson regression analyses with robust variance estimates, adjusting for clustering of patients within physicians, to examine the association between BMI and physician perception of medication adherence. The mean (s.d.) BMI was 32.6 (7.7) kg/m2. Forty‐five percent of patients were perceived as nonadherent to medications by their physicians. Higher BMI was significantly and negatively associated with being perceived as adherent to medication (prevalence ratio (PrR) 0.76, 95% confidence interval (CI): 0.64–0.90; P = 0.002; per 10 kg/m2 increase in BMI). BMI remained significantly and negatively associated with physician perception of medication adherence after adjustment for patient and physician characteristics (PrR 0.80, 95% CI: 0.66–0.96; P = 0.020). In this study, patients with higher BMI were less likely to be perceived as adherent to medications by their providers. Physician perception of medication adherence has been shown to affect prescribing patterns in other studies. More work is needed to understand how this perception may affect the care of patients with obesity. 相似文献