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91.
Virulent human strains of group G streptococci express a C5a peptidase enzyme similar to that produced by group A streptococci. 总被引:10,自引:6,他引:4 下载免费PDF全文
Specific proteolytic destruction of the human chemotaxin, C5a, is a property of group A and B streptococcal pathogens. Here we show that virulent group G streptococci from human sources also express C5a peptidase activity. The enzyme responsible for this activity is approximately the same size as and is antigenically similar to that produced by group A streptococci. On the basis of Southern hybridization analysis with an internal fragment of the group A C5a peptidase gene (scpA) as a probe, a copy of this gene was found in the genome of all group G human isolates tested. Comparison of partial restriction maps of scpA and scpG revealed significant similarity between the two genes. Group G strains isolated from dogs and cows were found to lack C5a peptidase activity and did not hybridize to the scpA-specific probe. The association of this activity with three streptococcal species suggests that elimination of phagocyte chemotactic attractants is a more universal virulence mechanism than originally anticipated. 相似文献
92.
E.K. Lavu FRCPA M. Nelson M.Sc PhD H.J. Popp AAIMS BA J. Gibson FRCP FRCPA PhD H. Kronenberg DCP FRCP FRCPA FRCPath H. Pearson FAIMS A. Child FRCOG 《The Australian & New Zealand journal of obstetrics & gynaecology》1997,37(2):180-183
Summary: regnant women who attended antenatal clinics at King George V Hospital, the Birth Centre or were referred by obstetricians from February to July. 1996 were screened for the platelet antigen HPA-la by flow cytometry. Forty out of 2300 (1.7%) were found to be negative for this antigen . Of the 28 women followed throughout their pregnancy, none developed antibody to HPA-la. Platelet counts performed on samples from 17 babies born to 17 of these mothers were all normal. This study proves the simplicity and rapidity of flow cytometry for platelet antigen screening. The results were comparable with the Solid Phase Red Cell Adherence (SPRCA) method and with PCR. The lack of a plentiful supply of specific antibody and the rarity of fetomaternai alloimmune thrombocytopenia (FMAIT) argue against the introduction of routine screening for maternal HPA-la status at the present time. 相似文献
93.
94.
Studies were conducted relating mosquito production in small ponds to presence or absence of larvivorous fishes. Data collected showed that native killifish and introduced mosquitofish controlled mosquito larvae at the same level and support the use of indigenous fish species in mosquito abatement programs. 相似文献
95.
A comparison of motor unit behaviour in young and aged subjects 总被引:1,自引:0,他引:1
We evaluated motor unit behaviour in young and aged subjects during ramped tension development and release to 10% maximum voluntary contraction requiring 10 seconds to complete. Six young and six elderly adults performed isometric abductor digiti minimi muscle contractions while motor units were recorded with implanted fine wire electrodes. Computer interactive programs yielded interspike interval (ISI) data for 16 units from the young and for 15 units from the aged subjects. Mean ISIs for young were 88.4 ms for shortening and 96.5 ms for lengthening contractions. Units from the aged had ISIs of 110.5 ms and 117.1 ms for shortening and lengthening contractions. Some evidence for between-group differences in firing pattern during ascending and descending ramps was also found. 相似文献
96.
97.
Michael Steinitz Alejandro Livoff Sara Tamir Talma Brenner 《Medical oncology (Northwood, London, England)》1993,10(1-2):49-52
A universal method for selection of surface marker-positive cells is described. The cells, admixed with an excess of surface marker-negative cells, are In-st labelled with a specific biotinylated ligand and then isolated with the aid of monoclonal, anti-biotin coated beads. The method enables selection and isolation of cells with a frequency as low as 10-4. The ligand can be an antigen (for selection of infrequent antibody-producing cells), an antibody (for selection of surface antigen-positive cells) or other molecules (for selection of specific receptor-positive cells). 相似文献
98.
Acid phosphatases 总被引:1,自引:0,他引:1
99.
Carlo. Montoli MD Marco De Pietri MD Sara Barbieri MD Fabio DAngelo MD 《The Journal of foot and ankle surgery》2004,43(5):321-326
Total extrusion of the talus without recovery of the bone is a very unusual injury. The authors present a case of a 25-year-old man who sustained an open total enucleation of the talus in a motorcycle accident. The talus was not recovered at the scene of the accident. An immediate tibiocalcaneal stabilization was performed by using an external fixator. In the postoperative period, a polymicrobic infection was observed and treated with parenteral antibiotics. Nine months after injury, the patient developed an infection of both the empty space and the distal third of the tibia. A wound debridement with tibial sequestrectomy and insertion of gentamicin-impregnated polymethylmethacrylate beads was performed. Three months later, after multiple negative bacteriologic examinations, a tibiocalcaneal arthrodesis with staples and autogenous bone graft was performed. Because of a pseudoarthrosis, the patient underwent a revision of the arthrodesis by retrograde tibiocalcaneal nailing, achieving clinical and radiographic success. The definitive treatment of total enucleation of the talus is still controversial because of its rarity and the high rate of complications, such as avascular necrosis, osteomyelitis, and ankle stiffness. In this case, without recovery of the talus, retrograde nailing afforded good stability by bypassing the bone defects. 相似文献
100.
Identification of symptoms that are directly responsive to neuroleptic drugs at progressive phases of treatment is important for monitoring drug response and understanding the relationship between neurochemical mechanisms of drug action and disordered behavior. Using multiple regression analyses that controlled for pretreatment severity, we identified those symptoms that improved in direct relation to serum concentrations of perphenazine after 10 days of treatment. Improvement in two positive symptoms of psychosis--hallucinations and conceptual disorganization--appears to be related to perphenazine level and useful for assessment of early drug response. 相似文献