Induction of an antigen-specific CTL response by a conformationally biased agonist of human C5a anaphylatoxin as a molecular adjuvant

A conformationally biased decapeptide agonist of human C5a anaphylatoxin (YSFKPMPLaR) was used as a molecular adjuvant in stimulating an Ag-specific CTL response against murine P815S target cells expressing an Ld-restricted CTL epitope of the hepatitis B surface Ag (HBsAg). Groups of BALB/c mice (H-2d) were immunized with aqueous solutions of the HBsAg CTL epitopes (IPQSLDSWWTSL and IPQSLDSWWTSLRR); the C5a agonist (YSFKPMPLaR); the C5a agonist and HBsAg CTL epitopes admixed (IPQSLDSWWTSL and IPQSLDSWWTSLRR + YSFKPMPLaR); the C5a-active, HBsAg CTL epitope-C5a agonist constructs (IPQSLDSWWTSLYSFKPMPLaR, IPQSLDSWWTSLRRYSFKPMPLaR, and IPQSLDSWWTSLRVRRYSFPMPLaR); a C5a-inactive, reverse-moiety construct (YSFKPMPLaRRRIPQSLDSWWTSL); and a C5a-attenuated, carboxyl-terminal-blocked construct (IPQSLDSWWTSLRRYSFKPMPLaRG). Ag-specific CD8+ CTL responses were observed after the secondary boost in the absence of any added adjuvant only in mice that were immunized with C5a-active contructs, IPQSLDSWWTSLRRYSFKPMPLaR and IPQSLDSWWTSLRVRRYSFKPMPLaR. These two C5a-active immunogens contained potential subtilisin-sensitive linker sequences between the HBsAg CTL epitope and the C5a agonist; i.e., a double-Arg (RR) and a furin protease sensitive sequence (RVRR). The introduction of these potentially cleavable sequences may be a method of increasing the likelihood of liberating the CTL epitope from the C5a agonist by intracellular proteases, thereby facilitating entry of the epitope into Ag-processing pathways via an exogenous route.

A longitudinal study of the health impacts of a petroleum refinery

Emissions from a petroleum refinery in Oakville, Ont., have been the source of longstanding health concerns among residents in the surrounding community. Between 1992 and 1997, the refinery implemented extensive odour reduction measures through improvements in waste water treatment, in sulphur recovery and combustion. In this paper, we present the main findings of a recent longitudinal analysis using data from community health surveys conducted in 1992 and 1997, before and after implementation of the odour reduction plan. The results show a decline in the frequency of odour perception and annoyance by residents whereas the reporting of cardinal and general symptoms among adults and children was virtually unchanged. Odour perception and annoyance were strongly related to symptom reporting in both years supporting the hypothesis that the effect of refinery emissions on residents' health is odour mediated. The findings extend our understanding of the psychosocial basis of symptom reporting in the vicinity of refineries.

Induction of protective immunity to Dictyocaulus viviparus in calves while under treatment with endectocides

Three groups of five parasite-naive calves were used. The treatments were: (a) Group 1 calves were weighed on Day 0 and injected with doramectin at 200 microg/kg. From Day 1 to 19 they were dosed orally with 2000 infective larvae of Dictyocaulus viviparus. On Day 28 they were again injected with doramectin, and infected with D. viviparus larvae from Days 33 to 41. They were then left untreated until Day 81 when they were infected with 20 infective larvae of D. viviparus per kg body weight. They were killed on Day 110 and lungworms were counted; (b) Group 2 calves were immunised with oral lungworm vaccine on Days 0 and 28, and infected and slaughtered as Group 1 on Days 81 and 110, respectively; (c) Group 3 calves acted as infection controls. Blood samples were taken at Days 0, 21, 49, 77 and 110 for antibody tests to D. viviparus. At autopsy there were no significant differences between the number of lungworms from Groups 1 and 2 (Means 17.4 and 31.3, respectively); Group 1 had significantly less value than Group 3 (Mean 228) (p < 0.05). Increased antibody titres to the larval sheath of the infective larvae were observed from Groups 1 and 2, showing that the larvae in Group 1 had penetrated the intestine before being killed by the circulating anthelmintic. This experiment shows that if calves are exposed to infective larvae while under systemic endectocide cover, an immune reaction is stimulated.

Restructuring public health in Ontario: implications for heart health promotion

Community-based heart health promotion is viewed as an effective means of reducing cardiovascular disease risk. Although public health agencies have a central role in the implementation and dissemination of heart health programmes, their effectiveness is being challenged by major structural changes to Provincial public health systems across Canada, although the impacts of the changes have received relatively little attention in the research literature. As part of the Canadian Heart Health Initiative--Ontario Project (CHHIOP), this study used a qualitative approach to address the perceived implications of these changes to Ontario's public health system for heart health promotion. Interviews (n = 38) were conducted in eight public health units with staff most familiar with managing and/or delivering heart health activities. The results are mixed; that is, while many see the future of heart health promotion programming in Ontario as being at risk, others see recent changes as a step forward toward their institutionalization, particularly in light of recent funding decisions made by the Ministry of Health's Health Promotion Branch.

Restructuring public health in Ontario: implications for heart health promotion

Community-based heart health promotion is viewed as an effective means of reducing cardiovascular disease risk. Although public health agencies have a central role in the implementation and dissemination of heart health programmes, their effectiveness is being challenged by major structural changes to Provincial public health systems across Canada, although the impacts of the changes have received relatively little attention in the research literature. As part of the Canadian Heart Health Initiative--Ontario Project (CHHIOP), this study used a qualitative approach to address the perceived implications of these changes to Ontario's public health system for heart health promotion. Interviews (n = 38) were conducted in eight public health units with staff most familiar with managing and/or delivering heart health activities. The results are mixed; that is, while many see the future of heart health promotion programming in Ontario as being at risk, others see recent changes as a step forward toward their institutionalization, particularly in light of recent funding decisions made by the Ministry of Health's Health Promotion Branch.

Frey's syndrome and parotidectomy flaps: A retrospective cohort study

Gustatory sweating, also known as Frey's syndrome, is a recognized phenomenon after parotidectomy. The incidence of clinically significant gustatory sweating may be dependent on the thickness of the skin flap that is elevated at the time of surgery. Dissection in the subcutaneous level or the deeper sub-superficial musculoaponeurotic system level are 2 commonly used techniques in the operation. Twenty-eight patients were prospectively evaluated for Frey's syndrome after superficial parotidectomy. Thirteen patients underwent subcutaneous and 15 patients sub-superficial musculoaponeurotic system flap elevation. The overall incidence of gustatory sweating was determined, and a comparison of the two surgical techniques was assessed subjectively by patient interview-questionnaire and objectively evaluated with starch-iodine testing.

Cell phenotype as a target of drug therapy in chronic inflammatory diseases

Many diseases share common pathological changes which could in principle be targets for new drugs. Vascular leakage of plasma and migration of cells into perivascular tissues are common to chronic inflammatory diseases such as asthma, atherosclerosis, arthritis, and proliferative nephropathy as well as some non-inflammatory proliferative disorders such as diabetes mellitus. Individual components of plasma have been shown to stimulate cellular proliferation, matrix deposition and phenotypic change, leading to tissue-damaging structural changes. Whereas most anti-inflammatory drugs either downregulate expression of inflammatory mediators or inhibit their actions on cells, there are alternate potential therapeutic strategies described here based on moderating vascular leakage or its consequences in chronic diseases. The hypothesis is that drugs that can modify a cell's phenotype could be used to limit structural changes which accompany inflammation and thus reduce permanent debility resulting from these diseases. Such drugs include the differentiating agents being developed for cancer therapy.

Selected disorders of muscle and the neuromuscular junction

A variety of disorders affect the muscles or the neuromuscular junction of dogs and cats, most often causing weakness, exercise intolerance, and muscular pain or atrophy. The myopathies are infectious, immune-mediated, inherited or acquired secondary to systemic disease. Acquired myasthenia gravis is a common disorder of the neuromuscular junction, which clinically resembles a myopathy. Reaching a specific diagnosis is essential to determine optimal therapy and prognosis for each of the commonly recognized disorders.

Isolated arteriovenous dialysis access graft segment infection: the results of segmental bypass and partial graft excision

Arteriovenous (AV) access graft infection results in disruption of dialysis and usually necessitates graft removal when the entire graft is involved. The management of an isolated infected segment of an otherwise noninfected AV access graft, however, remains controversial. To evaluate the utility of segmental bypass and partial graft excision for the treatment of an isolated infected AV access graft segment, 17 consecutive cases in 12 patients (7 females/5 males; 14 arm grafts/3 leg grafts; median age = 69 years) were analyzed on a vascular teaching service that performed 1244 total access procedures from January 1995 through February 1999. Infections presented as a draining sinus or a sinus with hemorrhage emanating from an area over the graft. At operation, the infected sinus was covered by a transparent occlusive dressing and the graft was explored through clean incisions proximal and distal to the infected segment. If the graft was incorporated and free of infection, a piece of expanded polytetrafluoroethylene (ePTFE) was anastomosed proximally end-to-end and tunneled through noninfected tissues around the infected sinus. After the distal anastomosis was performed, the skin incisions were closed and covered with occlusive dressings. The infected graft segment was then removed through the infected sinus wound. The technique of segmental bypass and partial graft excision results in predictable eradication of infection, graft salvage, and maintenance of uninterrupted dialysis in patients presenting with an isolated AV dialysis access infection.

Emphysematous cholecystitis in a Siberian husky

A 6-year-old, intact male Siberian husky was evaluated for a 24-hour history of vomiting and lethargy. Diagnosis of emphysematous cholecystitis was achieved based on survey abdominal radiographs, a barium contrast gastrointestinal series, and abdominal ultrasound. Diagnosis and medical and surgical management of the condition are discussed.

Tissue-specific expression of functional isoforms of mouse folypoly-gamma-glutamae synthetase: a basis for targeting folate antimetabolites

Folates and folate antimetabolites are metabolically trapped in mammalian cells as polyglutamates, a process catalyzed by folylpoly-gamma-glutamate synthetase (FPGS). Using 5'-rapid amplification of cDNA ends, RNase protection assays, transfection of cDNAs into FPGS-deficient cells, and kinetic analysis of recombinant enzymes expressed in insect cells, it was determined that the species of active FPGS in mouse liver and kidney was different from that in mouse tumor cells, bone marrow, and intestine. The NH2-terminal peptide of hepatic enzyme contained 18 amino acids not found in enzyme from dividing tissues, and the specificity of the two isoforms for antifolates also differed, suggesting different architecture of the active sites. In most tissues, the expression of one isozyme or the other was an all-or-nothing event. The exclusive use of one of two alternative sets of initial coding exons in different tissues underlies this phenomenon, suggesting the design of antifolates specific for activation by individual FPGS isoforms and hence tissue-selective targeting of antifolate therapy for cancer, arthritis, or psoriasis.

Response-selective C5a agonists: differential effects on neutropenia and hypotension in the rat

Some in vivo activities of two complement C5a agonist analogues have been evaluated by measuring changes in blood pressure and neutropenia in the rat and comparing the results with their receptor affinities in peritoneal macrophages and polymorphonuclear leucocytes (PMNs). In vitro C5a receptor (C5aR) binding experiments showed that YSFKPMPLaR and YSFKD(NMeNle)PlaR had similar affinities for the macrophage C5aR (IC50 0.2, 0.1 microM respectively). In PMNs, the affinity of YSFKPMPLaR (IC50 0.1 microM) was similar to that in macrophages, whereas the affinity of YSFKD(NMeNle)PLaR for the PMN C5aR was >100 microM. Given i.v., YSFKD(NMeNle)PLaR had similar activity to YSFKPMPLaR on blood pressure but did not cause neutropenia. These results demonstrate selectivity of a new C5a agonist in vitro, which is paralleled in vivo. The results suggest the possibility of developing selective agonists of C5a for in vivo use in humans.

Prophylactic inferior vena cava filters in trauma patients at high risk: follow-up examination and risk/benefit assessment

PURPOSE

The efficacy of prophylactic inferior vena cava filters in selected trauma patients at high risk has come into question in relation to risk/benefit assessment. To evaluate the usefulness of prophylactic inferior vena cava filters, we reviewed our experience and overall complication rate.

METHODS

From February 1991 to April 1998, the trauma registry identified 7333 admissions. One hundred eighty-seven prophylactic inferior vena cava filters were inserted. After the exclusion of 27 trauma-related deaths (none caused by thromboembolism), 160 patients were eligible for the study. The eligible patients were contacted and asked to complete a survey and return for a follow-up examination to include physical examination, Doppler scan study, vena cava duplex scanning, and fluoroscopic examination. The patients' hospital charts were reviewed in detail. The indications for prophylactic inferior vena cava filter insertion included prolonged immobilization with multiple injuries, closed head injury, pelvic fracture, spine fracture, multiple long bone fracture, and attending discretion.

RESULTS

Of the 160 eligible patients, 127 were men, the mean age was 40.3 years, and the mean injury severity score was 26.1. The mean day of insertion was hospital day 6. Seventy-five patients (47%) returned for evaluation, with a mean follow-up period of 19.4 months after implantation (range, 7 to 60 months). On survey, patients had leg swelling (n = 27), lower extremity numbness (n = 14), shortness of breath (n = 9), chest pain (n = 7), and skin changes (n = 4). All the survey symptoms appeared to be attributable to patient injuries and not related to prophylactic inferior vena cava filter. Physical examination results revealed edema (n = 12) and skin changes (n = 2). Ten Doppler scan studies had results that were suggestive of venous insufficiency, nine of which had histories of deep vein thrombosis. With duplex scanning, 93% (70 of 75) of the vena cavas were visualized, and all were patent. Only 52% (39 of 75) of the prophylactic inferior vena cava filters were visualized with duplex scanning. All the prophylactic inferior vena cava filters were visualized with fluoroscopy, with no evidence of filter migration. Of the total 187 patients, 24 (12.8%) had deep vein thrombosis develop after prophylactic inferior vena cava filter insertion, including 10 of 75 (13.3%) in the follow-up group, and one patient had a nonfatal pulmonary embolism despite filter placement. Filter insertion complications occurred in 1.6% (three of 187) of patients and included one groin hematoma, one arteriovenous fistula, and one misplacement in the common iliac vein.

CONCLUSION

This study's results show that prophylactic inferior vena cava filters can be placed safely with low morbidity and no attributable long-term disabilities. In this patient population with a high risk of pulmonary embolism, prophylactic inferior vena cava filters offered a 99.5% protection rate, with only one of 187 patients having a nonfatal pulmonary embolism.

The impact of a community-wide vascular access program on the management of graft thromboses in a dialysis population of 495 patients

BACKGROUND

The unpredictability of prosthetic vascular access thrombosis precludes the scheduling of elective graft thrombectomy. This results in inconsistent dialysis for patients, as well as logistical challenges for dialysis clinics and surgeons, and increased cost. In an effort to solve this problem a community-wide, prospective vascular access program (VAP) was established. This study evaluates the impact of the VAP by comparing the operative procedures and outcomes of vascular access surgery performed in the community before and after establishment of the program.

METHODS

All 17 surgeons who perform vascular access, representing five independent practice groups in Greenville, South Carolina, formed a VAP in November 1996. Dialysis patients were pooled, and all graft thrombectomies were managed on a rotational basis by a surgeon assigned daily to a specifically designated access thrombectomy operating room. The hospital records of all patients undergoing vascular access procedures from November 1, 1995, through October 31, 1996 (pre-VAP), and November 1, 1996, through October 31, 1997 (post-VAP), were reviewed.

RESULTS

Comparison of the pre-VAP and post-VAP groups showed no significant difference in the number of patients undergoing vascular access procedures (391 versus 378), number of vascular access procedures performed (1034 versus 1,048), or average number of vascular access procedures performed per patient (2.64 versus 2.79). There was no statistical difference in the number of thrombectomies and revisions (786 versus 765; P = 0.114) or thrombectomies alone (248 versus 283; P = 0.114) in the pre-VAP and post-VAP groups. There was a significant increase in the number of procedures performed on an outpatient basis in the post-VAP group (757; 73%) compared with the pre-VAP group (575; 56%); P <0.001. There was also a significant difference in the percentage of cases performed after 6:00 PM in the pre-VAP group (262; 25%) compared with the post-VAP group (48; 4.5%; P = 0.001).

CONCLUSIONS

Dialysis graft thrombosis, occurring in 75% of our patients annually, represents a substantial logistical dilemma necessitating the incorporation of 1,000 additional operations into a busy elective surgery schedule. An organized VAP reduces inpatient hospitalization, minimizes expensive after hours surgery, and enhances patient and physician convenience while providing a mechanism to monitor clinical outcomes and assure timely dialysis.

The effects of salbutamol, beclomethasone, and dexamethasone on fibronectin expression by cultured airway smooth muscle cells

Possible mechanisms of adverse drug effects in asthma include worsening of cellular hyperplasia and stimulation of extracellular matrix deposition. In this study, salbutamol, dexamethasone and beclomethasone were investigated to ascertain their ability to induce mitogenesis and stimulate fibronectin expression in cultured canine airway smooth muscle cells. In cells maintained in serum-free media for 72 h, salbutamol (1 nM-10 microM) caused mitogenesis. The control cells had 2.57 +/- 0.34 x 10(5) cells per ml (mean +/- SEM, N = 13), while salbutamol (1 microM) caused a maximal increase in cell number to 3.57 +/- 0.23 x 10(5) cells/ml (P < 0.01). In cells stimulated to replicate by addition of either fetal bovine serum or canine serum, no additional mitogenic effect of salbutamol was seen. Salbutamol did not have a detectable quantitative effect on fibronectin matrix expression. The glucocorticoids, beclomethasone and dexamethasone, significantly altered fibronectin expression by cultured airway smooth muscle cells. Beclomethasone increased fibronectin expression, while dexamethasone decreased expression.

Development of C5a receptor antagonists

During host defense, the human complement system of plasma proteins initiates inflammatory and cellular immune responses to stimuli such as infectious organisms, chemical and physical injury, radiation and neoplasia. Elevated levels of one of these plasma proteins C5a, a 74 amino acid peptidic anaphylatoxin which is one of the most potent pro-inflammatory agents, correlate with the initiation and development of many inflammatory diseases. New agents which prevent binding of C5a to its G-protein-coupled receptors can inhibit the pro-inflammatory actions of C5a and thus be potentially used to treat chronic inflammatory disorders driven by complement activation and C5a production. In recent years significant progress has been made towards the development of potent antagonists of human C5a receptors and clinically useful compounds can reasonably be expected within the next few years.

Sheep scab--environmental considerations of treatment with doramectin

The paper reviews the recent change in attitudes to dipping sheep and the proposed legal requirements to prevent and treat sheep scab. The implications of fulfillment of all the requirements of the European Groundwater Directive and the probable resultant increase of the use of injectable endectocides as an alternative to plunge dipping are discussed in relation to their likely frequency of use and potential ecological impact. In particular the properties of doramectin, one of the most recently introduced, are examined in relation to its use for the treatment of sheep scab.

Low-molecular-weight peptidic and cyclic antagonists of the receptor for the complement factor C5a

Activation of the human complement system of plasma proteins during immunological host defense can result in overproduction of potent proinflammatory peptides such as the anaphylatoxin C5a. Excessive levels of C5a are associated with numerous immunoinflammatory diseases, but there is as yet no clinically available antagonist to regulate the effects of C5a. We now describe a series of small molecules derived from the C-terminus of C5a, some of which are the most potent low-molecular-weight C5a receptor antagonists reported to date for the human polymorphonuclear leukocyte (PMN) C5a receptor. 1H NMR spectroscopy was used to determine solution structures for two cyclic antagonists and to indicate that antagonism is related to a turn conformation, which can be stabilized in cyclic molecules that are preorganized for receptor binding. While several cyclic derivatives were of similar antagonistic potency, the most potent antagonist was a hexapeptide-derived macrocycle AcF[OPdChaWR] with an IC50 = 20 nM against a maximal concentration of C5a (100 nM) on intact human PMNs. Such potent C5a antagonists may be useful probes to investigate the role of C5a in host defenses and to develop therapeutic agents for the treatment of many currently intractable inflammatory conditions.

Homologous serum-stimulated fibronectin synthesis in human retinal pigmented epithelial cells

PURPOSE

Fibronectin expression has been recorded in subretinal membranes from patients with proliferative vitreoretinopathy (PVR). Retinal pigmented epithelial (RPE) cells are a major cellular component of PVR membranes and synthesize fibronectin. We investigated the effects of human serum (as a model of vascular leakage in vivo) on the expression of fibronectin by cultured human RPE cells and compared the responses to those stimulated by fetal bovine serum (FBS).

METHODS

Human RPE cells were incubated in M199 with 1, 10 and 40% human adult serum or FBS for 72 h.

RESULTS

Retinal pigmented epithelial cells expressed maximum extracellular matrix fibronectin when exposed to 40% human serum using immunohistochemistry. Using ELISA to quantify fibronectin, 10 and 40% human serum significantly increased the total fibronectin (P < 0.01; n = 4), whereas FBS did not affect fibronectin expression.

CONCLUSIONS

The results show that human serum contains substances stimulating fibronectin synthesis in human RPE cells.

The pitfalls of establishing a statewide vascular registry: the South Carolina experience

Concerned about the inadequacy of a centralized database and the importance of low morbidity and mortality on carotid endarterectomy efficacy, the South Carolina Vascular Surgical Society prospectively instituted a computer registry for carotid procedures performed by its members, to establish a statewide standard of practice. From January 1994 through December 1997, 23 of the 30 physician members voluntarily registered data on 1652 carotid operations at 14 hospitals into a central database. Blinded results were reviewed biannually. Complete data (1995-1997) were available for 1199 cases. The patients tended to be >64 years old (72%), male (62%), and white (93%). Carotid endarterectomy was the most frequently performed operation (90%). Perioperative complications (< or = 30 days) occurred in 173 patients (14.4%), including stroke (n = 19; 1.6%), death (n = 8; 0.7%), and stroke/death (n = 25; 2.0%). Although 23 surgeons (77% of the society) contributed some data, only 10 surgeons (33%) contributed complete data on >10 patients/year. Despite biannual efforts to boost participation, case entry remained stable (1994, 358; 1995, 347; 1996, 425; and 1997, 427), representing about one-third of the estimated carotid procedures performed in the state during that period. The cost of the registry was approximately $11,500. Audit of 8 surgeons revealed a >95 per cent match against the statewide discharge database and low error rate versus independent medical record review. This experience confirms that excellent outcomes after carotid endarterectomy are not limited to a few select centers and can be accomplished by adequately trained surgeons in a variety of institutional settings. Incomplete physician participation, however, inevitably raises questions about the utility of such efforts. Until volunteer registries induce full participation by heightening perceived physician benefit, their role will remain limited for future outcomes research.

Nonendarterectomy procedures of the carotid artery: a five-year review

Although the efficacy of carotid endarterectomy has been well established, nonendarterectomy procedures of the carotid bifurcation have only sporadically been reported. Of 334 consecutive nontraumatic carotid procedures performed on 321 patients from July 1992 until May 1997, 306 (91.6%) were carotid endarterectomies, 14 (4.2%) were carotid-subclavian bypasses/transpositions, and 14 (4.2%) were nonendarterectomy procedures of the carotid artery. These latter 14 cases (nine females and five males; mean age, 63 years) were all symptomatic (neurological or painful mass) and included carotid kink/coil resection (n = 3; 0.9%), endarterectomy and vertebral transposition (n = 2; 0.6%), carotid aneurysm resection (n = 2; 0.6%), carotid body tumor resection (n = 2; 0.6%), carotid stump ligation/external endarterectomy (n = 1; 0.3%), infected/bleeding carotid patch removal with vein graft replacement (n = 1; 0.3%), saphenous vein graft replacement (n = 1; 0.3%), carotid dilatation for fibromuscular dysplasia (n = 1; 0.3%), and descending aorta to carotid bypass (n = 1; 0.3%). With 30 day follow-up complete for all 334 carotid operations, 10 perioperative strokes (2.9%) and five deaths (1.5%) occurred for a combined stroke/death rate of 3.3 per cent. Of the 14 nonendarterectomy carotid artery operations, there were no strokes or deaths; with mean follow-up of 13 months, 13 patients (92.9%) are asymptomatic, patent, and disease-free. Three severe transient cranial nerve (CN) neuropraxias (21.4%), one myocardial infarction (7.1%), and one late death (mesenteric ischemia at 2 months), however, occurred. Although no statistical differences in stroke, death, and stroke/death occurred between the endarterectomy versus the nonendarterectomy group, transient CN injury was more common in the nonendarterectomy group (21.4% versus 4.1%; P = 0.027). Although nonendarterectomy procedures of the carotid bifurcation are infrequently needed, they seem safe, effective, and indicated in selected patients, despite a higher incidence of transient CN injury.

The role of the human Fc receptor Fc gamma RIIA in the immune clearance of platelets: a transgenic mouse model

In humans, the Fc receptor for IgG, FcgammaRIIA, is expressed on macrophages and platelets and may play an important role in the pathophysiology of immune-mediated thrombocytopenia. Mice lack the genetic equivalent of human FcgammaRIIA. To better understand the role of FcgammaRIIA in vivo, FcgammaRIIA transgenic mice were generated and characterized. One transgenic mouse line expressed FcgammaRIIA on platelets and macrophages at levels equivalent to human cells, and cross-linking FcgammaRIIA on these platelets induced platelet aggregation. Immune-mediated thrombocytopenia in this transgenic line was studied using i.v. and i.p. administration of anti-mouse platelet Ab. In comparison with matched wild-type littermates that are negative for the FcgammaRIIA transgene, Ab-mediated thrombocytopenia was significantly more severe in the FcgammaRIIA transgenic mice. In contrast, FcR gamma-chain knockout mice that lack functional expression of the Fc receptors FcgammaRI and FcgammaRIII on splenic macrophages did not demonstrate Ab-mediated thrombocytopenia. We generated FcgammaRIIA transgenic x FcR gamma-chain knockout mice to examine the role of FcgammaRIIA in immune clearance in the absence of functional FcgammaRI and FcgammaRIII. In FcgammaRIIA transgenic x FcR gamma-chain knockout mice, severe immune thrombocytopenia mediated by FcgammaRIIA was observed. These results demonstrate that FcgammaRIIA does not require the FcR gamma-chain for expression or function in vivo. Furthermore, taken together, the data suggest that the human Fc receptor FcgammaRIIA plays a significant role in the immune clearance of platelets in vivo.

An analysis of the geographic variation in cancer incidence and its determinants in Ontario

Cancer incidence data for the Ontario Public Health Units in 1980-91 were examined to investigate regional patterns and the existence of outlier values after adjustment for known risk factors. Candidate risk factors were derived from the Ontario Health Survey and the census. Weighted regressions were fit to the data, and the spatial pattern of the residuals was analyzed. The number of outlier data points with significant elevations or reductions in risk was close to that expected by chance. They were dispersed geographically, and occurred in a variety of cancer types. We conclude that, in general, most of the geographic variation in cancer risk can be associated with variation in known risk factors, and that there appear to be no broad regional effects remaining after adjustment for these factors. A few cancer sites provide limited evidence of regional effects that may warrant further investigation.

Community-based heart health promotion: perceptions of facilitators and barriers

This paper examines factors that facilitate or impede the implementation of heart health activities in Ontario public health departments using survey (n = 262) and depth interview (n = 56) data from Canadian Heart Health Initiative-Ontario Project (CHHIOP). The data were consistent in revealing factors related to leadership, staffing, resources, internal organization, and characteristics of the surrounding community as the primary facilitators or barriers. Diversity within these common themes reflected variation due to external factors in the communities served by the health unit and factors internal to the health unit itself. The findings advance knowledge of the factors that influence predisposition and capacity to undertake community-based heart health promotion in public health departments, and they underscore the challenge of achieving integrated programs among partner agencies.