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81.
The 120-kDa surface protein antigens (SPAs) of typhus rickettsiae are highly immunogenic and have been shown to be responsible for the species-specific serological reactions of the typhus group rickettsiae. To study the immunochemistry of these proteins, overlapping decapeptides encompassing the whole protein were synthesized on derivatized polyethylene pins. A modified enzyme-linked immunosorbent assay was used to identify epitopes recognized by rabbit hyperimmune antisera to Rickettsia prowazekii SPA. Eight distinct epitopes were mapped by this method in three regions. Four of the epitopes, which were located in the carboxyterminus of mature processed SPA, were strongly competitively inhibited by native folded SPA but not by intact rickettsiae, suggesting that they were on the SPA surface but not exposed on the rickettsial surface. Three of these epitopes were present on both R. prowazekii and Rickettsia typhi SPAs. The immunoreactivities of five epitopes were further characterized by synthesizing modified peptides. Glycine substitution experiments determined the critical residues in the epitopes. The dependence of binding of the peptide epitopes to the polyclonal antisera was mapped to single residues. The limited number and weak reactivity of linear peptide epitopes observed with human and rabbit sera, possibly due to a lack of the methylated amino acids which are present in rickettsia-derived SPA, suggest that the present approach will not provide useful synthetic antigens for diagnosis of typhus infections. 相似文献
82.
OBJECTIVE: A significant proportion of patients who undergo cardiac surgery or carotid endarterectomy appear to develop subtle cognitive deficits, with the occurrence of multiple cerebral microemboli documented by Doppler ultrasound during these procedures. We used an experimental multiple cerebral embolism model to test whether treatment with tirilazad (U74006F), a putative inhibitor of lipid peroxidation, would improve functional outcome after multiple brain emboli. DESIGN: Randomized, controlled trial. SETTING: Animal care facility procedure room. SUBJECTS: A total of 44 New Zealand White rabbits weighing 2 to 3.0 kg. INTERVENTIONS: Variable quantities of 125I-labeled 50-microns microspheres were injected via a carotid catheter to produce multifocal brain ischemia. Rabbits randomly received either: tirilazad (3 mg/kg i.v.) 5 mins before embolization (pretreatment), or 30 mins after embolization (posttreatment) followed by 1.5 mg/kg every 5 hrs x 3 doses. A third group received vehicle only (control) 5 mins before, followed by three doses every 5 hrs. MEASUREMENTS AND MAIN RESULTS: The animals were rated by a blinded observer at 18 hrs after ischemia and scored as either grossly abnormal/dead or normal. The animals were killed and the amount of microspheres in the brain that were required to produce abnormal function at 18 hrs was calculated for each group. To determine if tirilazad also modified leukocyte function during ischemia, neutrophil adhesion to laminin was determined at baseline and 18 hrs after ischemia using a myeloperoxidase assay. In this study, pretreatment, but not posttreatment with tirilazad produced a significant reduction in neurologic deficits. Tirilazad also attenuated postischemic increases in neutrophil adhesion. CONCLUSIONS: Tirilazad pretreatment reduces neurologic deficits from multiple cerebral emboli. This significant protective effect suggests that pretreatment with tirilazad may play a role in clinical situations where the risk of cerebral emboli is high, with changes in leukocyte adherence as a potential mechanism. 相似文献
83.
JT Sandlund T Fonseca T Leimig L Verissimo R Ribeiro V Lira CW Berard J Sixbey WM Crist L Mao G Chen CH Pui M Heim F Pedrosa 《Canadian Metallurgical Quarterly》1997,11(5):743-746
The purpose of this paper was to define the histologic distribution, clinical features, and treatment response of childhood non-Hodgkin lymphoma (NHL) in northeastern Brazil. We reviewed medical records and histopathologic studies of 98 children treated for NHL from 1980 to 1987 at a major pediatric cancer center in Recife, Brazil. Treatment outcome was evaluated in relation to tumor burden (stage and serum LDH) and type of therapy (LSA2L2 vs other multiagent chemotherapy). There was a striking predominance of the small noncleaved cell (Burkitt) subtype, which occurred in 92 of the 98 children and adolescents diagnosed with NHL. Subsequent analyses focused on these patients. The majority (n = 84) had advanced (stage III/IV) disease at diagnosis. The abdomen was the most common site of disease (84 cases); jaw involvement was rare (three cases). Five-year event-free survival (excluding treatment refusals) was significantly better for patients with limited vs advanced stage disease (75 +/- 14% vs 42 +/- 6%; P < 0.04). Elevated serum LDH (>500 U/l) was associated with a poorer outcome (P = 0.008). The type of chemotherapy did not affect EFS (P = 0.95). Only 39% of patients are long-term survivors, reflecting the high rate of septic deaths (25% of patients) and parental refusal/abandonment of therapy (10%). Epstein-Barr virus (EBV) was detected in tumor cells from eight of the 11 cases studied. In clinical presentation, these cases resemble sporadic Burkitt lymphoma, yet in their apparent responsiveness to LSA2L2 therapy and association with EBV, they do not. Childhood NHL in northeastern Brazil is predominantly of the Burkitt subtype, and is associated with clinical features that appear to distinguish it from the endemic and sporadic forms of this tumor. These cases may represent a third or intermediate subtype of Burkitt lymphoma. 相似文献
84.
JM Rogers M Usui BH KenKnight RE Ideker WM Smith 《Canadian Metallurgical Quarterly》1997,25(5):749-760
We have developed a method for quantifying the complexity of activation patterns observed during ventricular fibrillation (VF) that is based on our previously reported methodology for decomposing epicardial mapping data into a set of isolated wavefronts. One-half second datasets are acquired from a 21 x 24 array of unipolar electrodes (1 mm spacing), and the wavefronts are isolated. A correlation technique is used to compute the similarity between all possible pairs of the isolated wavefronts. From these data, the wavefronts are sorted into clusters, each of which represents a recurring wavefront morphology. We define multiplicity (M) as the number of clusters needed to account for 90% of the total activations in the VF episode. M measures the complexity of the rhythm. In repetitive patterns (e.g., sinus rhythm), M = 1, indicating that the same morphology repeatedly activates the mapped region. Typically, in VF, M > 1, with larger numbers representing more complex, disorganized patterns. As an example, we computed M at 5, 10, 15, and 20 sec after electrical induction of VF in six pigs. M decreased significantly (p < 0.001), suggesting increasing organization during this period. 相似文献
85.
86.
A Madaree WM Morris PK Ramdial IC McGibbon P Blignault 《Canadian Metallurgical Quarterly》1997,100(7):1803-1808
Chronic hematic cysts are rare conditions that usually present to the ophthalmic surgeons with displacement of the globe. There is usually no, or minimal, bone involvement. Two patients with unusual presentations of chronic orbital hematic cysts are reported. These cysts resulted in significant expansion and erosion of the bony orbits. The presentation, operative findings, and reconstruction are reported and discussed. 相似文献
87.
EW Hook WM McCormack D Martin RB Jones K Bean AN Maroli 《Canadian Metallurgical Quarterly》1997,41(8):1843-1845
In a randomized open study, 351 male patients with uncomplicated gonorrhea were given single oral doses of grepafloxacin (400 mg) or cefixime (400 mg). In the 299 microbiologically evaluable patients, urethral infections were cured in 99% (147 of 149) of those receiving grepafloxacin and 97% (145 of 150) of those given cefixime. Eradication rates for both regimens were 100% in the 16% (47 of 299) of participants who were infected with penicillin-resistant Neisseria gonorrhoeae and 97% in the 21% (62 of 299) of participants infected with tetracycline-resistant strains. Grepafloxacin is a well-tolerated alternative to cefixime for treatment of uncomplicated gonorrhea in males. 相似文献
88.
MO Hoekstra W van der Bij WJ de Boer B Wijnberg-Williams J Gerritsen WM van Aalderen 《Canadian Metallurgical Quarterly》1997,141(46):2229-2233
The first lung transplantation in the Netherlands was carried out in 1990. Since, the operation has been performed in over one hundred adults and two children (up to 16 years) with chronic respiratory insufficiency. Most lung transplantations in children are performed because of cystic fibrosis. After referral, the patient is given information about the operation and the pre- and postoperative periods, and the transplantation team advises on the time of screening. Some one-third of the children referred ultimately undergo transplantation; the others refrain from the operation, are rejected or die during the waiting period. Owing to a shortage of donor lungs the waiting period for transplantation may last over one year. A possible but controversial solution is donation of a pulmonary lobe by a close relative. Undergoing lung transplantation places a heavy (psychic) burden on the patient and his parents. Every patient after lung transplantation goes through an average of two or three periods of acute rejection. Chronic rejection occurs in 20-40%. Other complications are connected to medication (infections, renal dysfunction) or to the underlying disease (diabetes mellitus in cystic fibrosis). The percentages of survival for 1, 2 and 4 years are approx. 60-70, 55-60 and 30-50, dependent in part on the type of lung transplantation (unilateral, bilateral or combined heart-lung transplantation). A reasonable condition of the patient owing to timely referral is a positive prognostic factor. 相似文献
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