Antigenic and biological characterization of influenza virus neuraminidase (N2) with monoclonal antibodies

Competitive radioimmunoassays using monoclonal antibodies established that the neuraminidase of A/RI/5+/57 (H2N2) influenza can be divided into four overlapping antigenic regions. Antigenic regions 1 and 4 are sufficiently far apart so that there was no competition between antibodies for these sites. Region 1 is conserved in neuraminidases from N2 viruses over a 10-year period, while the other regions changed antigenically during this time. The antibodies belonging to groups 2 and 3 completely inhibited catalytic activity on fetuin substrate, whereas antibodies in groups 1 and 4 inhibited weakly or not at all. Antigenic region 2 can be further divided into four overlapping areas (2a, 2b, 2c, and 2d) based on the reactivity patterns of monoclonal antibodies with antigenic variants, chemically modified neuraminidase, and the ability of the antibodies to inhibit enzyme activity of different molecular weight substrates. Previous studies [R. G. Webster, V. S. Hinshaw , and W. G. Laver (1982) Virology 117, 93-104; D. C. Jackson and R. G. Webster (1982) Virology 123, 69-77] characterized only region 2 of the neuraminidase molecule. Each of the monoclonal antibodies inhibited virus release from MDCK cells when incorporated in an agar overlay, and some antibodies in each group inhibited hemagglutination by intact virus, but only antibodies in group 2 neutralized virus in embryonated eggs and permitted selection of antigenic variants. The results indicate that antibodies to some antigenic sites on the neuraminidase may inhibit virus release more efficiently than others, depending on their relation to the enzyme active center. None of the monoclonal antibodies inhibited the hemolytic activity of viruses possessing N2. Based on antigenic mapping and biological properties of the monoclonal antibodies, a topographical map of the neuraminidase can be constructed. It is proposed that antigenic regions 1 and 4 are spacially separated and, based on their failure to inhibit biological activity, may be located on the bottom surface of the molecule; region 3 may be on the top surface of the molecule but at some distance from the catalytic center. Antigenic region 2 probably encompasses most of the top surface of the molecule; region 2d being closest to the enzyme center, with subregions 2a and 2b adjacent to it on the top surface. Chemical treatment of the neuraminidase with trinitrobenzenesulfonic acid (TNBS) causes modification of the 2b region, confirming the antigenic mapping results.     

Effects of complement inhibition with soluble complement receptor-1 on vascular injury and inflammation during renal allograft rejection in the rat.

Complement is both an effector of the humoral immune response and a stimulator of leukocyte activation. To examine the influence of complement on the allograft response, we inhibited complement using recombinant human soluble complement receptor-1 (sCR1; TP10), in an unsensitized model of rat renal allograft rejection. Lewis to DA renal transplant recipients were treated daily with 25 mg/kg sCR1 or saline and sacrificed on days 1 to 5 after transplant. Transplanted organs were examined histologically and immunohistochemically for leukocyte subset markers and for the third component of complement, C3, and membrane attack complex deposition. A second set of recipients was followed from day 5 to day 9 to assess graft survival. sCR1-treated recipients displayed > 90% inhibition of plasma complement activity and a marked reduction in tissue C3 and membrane attack complex deposition. Inactivation of complement reduced the vascular injury such that there was almost complete sparing of vascular damage in day 5 sCR1-treated rats. There was a significant reduction in infiltrating leukocytes by day 5 after transplant, and complement inhibition delayed the time to reach a histologically defined end point of graft survival from 5 days in controls to 9 days in the sCR1-treated group. These results imply that the vascular and cell-mediated injury arises, in part, from complement activation. The partial inhibition of these injuries by sCR1 may have functional implications for strategies to inhibit allograft rejection.     

Antigenicity of influenza virus hemagglutinin following chemical modification

Hemagglutinin (HA) molecules from a number of different strains of type A influenza virus were reacted with 1-fluoro 2–4-dinitrobenzene (FDNB) at pH values ranging from 8.4 to 10.3. HA was also reacted with tetranitromethane (TNM) or diazotized sulfanilic acid (DSA). Sequence studies on HA1 from HA molecules treated with FDNB, TNM, or DSA showed that certain lysine, tyrosine, or histidine residues were 100% substituted after the reaction, while others apparently did not react at all. DNP-substituted hemagglutinin molecules, isolated from FDNB-treated A/Memphis/1/71_H-BEL_N(H3N1) virus particles, had up to 58% of lysines substituted with DNP. These molecules, nevertheless, retained hemagglutinin activity and, as far as could be measured, the same capacity as the unsubstituted hemagglutinin to react with heterogeneous antiserum or a panel of monoclonal antibodies. These results suggest that those amino acid side chains able to react with FDNB (lysine, histidine, tyrosine, and cysteine) are either not present in the antigenic sites on the HA, or if they are, then either the side chains which bind antibody do not react with DNP, or the presence of DNP in the site does not affect its ability to combine with antibody. The results also suggest that substitution of more than half of the lysine in the hemagglutinin molecule does not cause any marked conformational changes, for such changes would be expected to affect the ability of the HA to combine with both cell receptors and antibody molecules. Similar findings with TNM-treated HA suggest that tyrosine is not an essential part of any antigenic site on H3 type HA. HA treated with diazotized sulfanilic acid lost HA activity, but its antigenicity was similar to that of untreated HA when tested with heterogeneous antisera, suggesting that histidine was not present in the antigenic sites. However, when HA from a monoclonal variant of A/Mem/1/71 (H3N2) virus with a sequence change from wild-type in HA1 of proline (143) to histidine (Laver, Air, and Webster, 1981) was reacted with diazotized sulfanilic acid, the histidine at position 143 in HA1 reacted completely and the HA lost the ability to bind antibody specific for the new antigenic site on this variant. However, treatment of this variant with FDNB did not lead to substitution of histidine 143.     

Country watch: Zimbabwe

Tsungirirai is a counseling and information service developed during 1994 in response to the growing problem of HIV/AIDS in the small town of Norton, southwest of Harare, Zimbabwe. The objectives of the project include identification of key leaders in the area, determination of the setting in which HIV was spreading, and community consultation in program design and implementation. Tsungirirai's initial activities included a series of workshops on participatory techniques particularly the LADA (Listening-Appraisal-Dialogue-Action) method for key leaders, community men, women, and adolescents. Workshop participants demonstrated different views concerning HIV/AIDS problems. Key leaders viewed the HIV/AIDS problem within the context of existing laws that contradict traditional mores, while the youth linked the problem of HIV to the issue of unemployment and lack of recreation. Lessons learned include the following: 1) stop talking and listen; 2) start where people are at instead of telling them what they already know; 3) let the people decide; 4) turn a dream into reality; and 5) facilitate awareness process instead of leading it.     

The management of women with breast symptoms referred to secondary care clinics in Sheffield: implications for improving local services

Information was collected about 302 women referred for breast symptoms and seen in surgical outpatient or outreach clinics during one month at two hospitals in Sheffield. Three-quarters of the women (n = 244) were referred to specialist breast clinics, 22% (n = 70) were referred to general surgical clinics and 3% (n = 6) were referred to outreach clinics. The ages of the women ranged from 16 to 85 years with a mean and median age of 45 years. Some 200 women (66%) presented with a lump or lumpiness, 42 women (14%) presented with pain, 29 women (10%) had a skin and/or nipple problem, and the remaining 31 women (10%) were concerned about their family history or reported other symptoms. A total of 23 women (8%) were diagnosed as having cancer, 180 (60%) were diagnosed as having benign breast disease, and 99 (33%) were diagnosed as normal. Of the 23 women with cancer, 22 were over 40 years of age; 21 women presented with a lump, one presented with pain, and one presented with metastatic disease. The time required to reach a final clinical diagnosis varied from the same day as the clinic visit to 35 weeks, with a median time of 3 weeks. Surgeons assessed the appropriateness of GPs' referrals for 257 cases and judged that 122 (47%) could have been managed by a GP. The implications of the findings for the organisation of specialist outpatient clinics are discussed, and a categorisation of women as either urgent or routine cases is suggested.     

Degenerated intramural pericytes ('ghost cells') in the retinal capillaries of diabetic rats.

One of the earliest histopathological signs of diabetic retinopathy is a selective loss of intramural pericytes from retinal capillaries. In the present study, the retinal vessels of rats with streptozotocin-induced diabetes (STZ Wistar) and rats with genetically-induced insulin dependent diabetes mellitus (BB Wistar) and non-insulin dependent diabetes mellitus (SHR/N-corpulent) were examined after 6 to 8 months duration for diabetes-related retinal microangiopathies. The SHR/N-corpulent (cp) rats were fed a 54% sucrose diet, whereas the STZ Wistar and BB Wistar rats were fed laboratory chow for 32 to 36 weeks. In all the diabetic rats, the retinal capillaries in enzyme-digested flat mounts exhibited an increase in periodic-acid-Schiff (PAS) staining and loss of pericytes compared to their respective euglycemic controls. Pericyte "ghosts", like those defined in human diabetes as intramural pockets lacking normal cell contents, were documented by high resolution micrographs in all the diabetic rats. Endothelial cell proliferation, capillary dilation, and varicose loop formation were noted in some of the diabetic rats. Hence, similar capillary lesions were found in very different groups of diabetic rats. The findings suggest that a chronic high tissue concentration of glucose is the underlying factor which triggers pathogenesis in the pericyte. Hyperglycemia-induced activation of endogenous aldose reductase of the polyol pathway is probably the initial insult, but other factors such as advanced glycosylation products may affect the final outcome.     

Phase I/II dose escalation study of recombinant human interleukin-11 following ifosfamide, carboplatin and etoposide in children, adolescents and young adults with solid tumours or lymphoma: a clinical, haematological and biological study

Thrombocytopenia remains the major dose-limiting toxicity of myelosuppressive chemotherapy in children with solid tumours. Recombinant human interleukin-11 (rhIL-11) has been approved by the Food and Drug Administration as treatment for adults with solid tumours and lymphomas with severe chemotherapy-induced thrombocytopenia. We conducted a phase I/II trial of rhIL-11 following ifosfamide, carboplatin and etoposide (ICE) chemotherapy in children with solid tumours or lymphomas. Patients received ifosfamide 1800 mg/m(2)/d for 5 d, carboplatin 400 mg/m(2)/d for 2 d and etoposide 100 mg/m(2)/d for 5 d with rhIL-11 subcutaneous (s.c.) at 25-125 microg/kg/d on days 6-33. Forty-seven patients with median age 10.5 years (range, 0.7-26 years) were studied. Median days to absolute neutrophil count >/=0.5 x 10(9)/l, platelet count >/=50 x 10(9)/l and platelet transfusions were 23, 18, 18, 16.5 and 18.5, 21, 20, 18 and 3, 3, 4, and 2 d at doses 25, 50, 75 and 100 Schulteg/kg respectively. There was a dose-dependent increase in C(max) (7.6-25.5 ng/ml), AUC(0-rho) (57-209 ng.h/ml) and T(1/2) (4-8.2 h) respectively. There was a 4% incidence of anti-IL-11 antibody formation. Clinically important adverse events to rhIL-11 were papilloedema and periosteal bone formation. In summary, rhIL-11 was well tolerated at doses of 相似文献   

Blind snakes beneath the surface: Continuing the legacy of Richard Thomas

Blind snakes (Scolecophidia) are small-bodied, enigmatic burrowing reptiles with members found on all continents except Antarctica. This Special Issue on blind snakes honors and advances the foundational studies by a remarkable anatomist, Richard Thomas. Richard is currently one of the living herpetologists to have described the greatest number of herpetofauna species, including many blind snake taxa. Recent interest in scolecophidian research at several conferences led to the development of this Special Issue on blind snake anatomy. This issue spans a diversity of papers, from biographical accounts of Richard's life and works, to a brief history of scolecophidian anatomical studies and the benefits of computed tomography (CT) technology, to a variety of studies on the skull and post-cranial osteology, cranial and jaw biomechanics related to subterranean lifestyles, evolution, and systematics of blind snake taxa from around the globe. This Special Issue will hopefully serve as a valuable resource and contribution to the field of blind snake anatomy research, and a joyful reflection on the life and career of a herpetologist who mentored and inspired a new generation of researchers in this area.     

Economic evaluations of occupational therapy approaches for people with cognitive and/or functional decline: A systematic review

With the ageing of the world's population comes significant implications for nearly all sectors of society, including health and aged care spending. Health and aged care systems need to respond to the increasing need for services for older people. Occupational therapy is concerned with maintaining a person's functional independence and well‐being from preventative and treatment perspectives. The aim of this systematic review was to identify the costs and outcomes of occupational therapy for people with cognitive and/or functional decline. The searches for this review were conducted on 23 September 2016 and updated on 20 April 2017. Full economic evaluation studies, partial economic evaluations, randomised trials reporting estimates of resource use or costs associated with intervention(s) and comparator(s) and studies with pre‐ and post‐intervention cost comparators were included. Thirteen studies met the inclusion criteria. The type and duration of occupational therapy intervention in the included studies varied, ranging from one‐off assessments through to systematic multicomponent programmes. Results suggested that structured occupational therapy interventions which comprised of multiple consultations and engaged caregivers delivered better functional and economic outcomes.