Minimal Collagen-Binding Epitope of Glycoprotein VI in Human and Mouse Platelets

Glycoprotein VI (GPVI) is a platelet-specific receptor for collagen and fibrin, regulating important platelet functions such as platelet adhesion and thrombus growth. Although the blockade of GPVI function is widely recognized as a potent anti-thrombotic approach, there are limited studies focused on site-specific targeting of GPVI. Using computational modeling and bioinformatics, we analyzed collagen- and CRP-binding surfaces of GPVI monomers and dimers, and compared the interacting surfaces with other mammalian GPVI isoforms. We could predict a minimal collagen-binding epitope of GPVI dimer and designed an EA-20 antibody that recognizes a linear epitope of this surface. Using platelets and whole blood samples donated from wild-type and humanized GPVI transgenic mice and also humans, our experimental results show that the EA-20 antibody inhibits platelet adhesion and aggregation in response to collagen and CRP, but not to fibrin. The EA-20 antibody also prevents thrombus formation in whole blood, on the collagen-coated surface, in arterial flow conditions. We also show that EA-20 does not influence GPVI clustering or receptor shedding. Therefore, we propose that blockade of this minimal collagen-binding epitope of GPVI with the EA-20 antibody could represent a new anti-thrombotic approach by inhibiting specific interactions between GPVI and the collagen matrix.

Flow chamber staining modality for real-time inspection of dynamic phenotypes in multiple histological stains

Traditional histological stains, such as hematoxylin-eosin (HE), special stains, and immunofluorescence (IF), have defined myriads of cellular phenotypes and tissue structures in a separate stained section. However, the precise connection of information conveyed by the various stains in the same section, which may be important for diagnosis, is absent. Here, we present a new staining modality-Flow chamber stain, which complies with the current staining workflow but possesses newly additional features non-seen in conventional stains, allowing for (1) quickly switching staining modes between destain and restain for multiplex staining in one single section from routinely histological preparation, (2) real-time inspecting and digitally capturing each specific stained phenotype, and (3) efficiently synthesizing graphs containing the tissue multiple-stained components at site-specific regions. Comparisons of its stains with those by the conventional staining fashions using the microscopic images of mouse tissues (lung, heart, liver, kidney, esophagus, and brain), involving stains of HE, Periodic acid-Schiff, Sirius red, and IF for Human IgG, and mouse CD45, hemoglobin, and CD31, showed no major discordance. Repetitive experiments testing on targeted areas of stained sections confirmed the method is reliable with accuracy and high reproducibility. Using the technique, the targets of IF were easily localized and seen structurally in HE- or special-stained sections, and the unknown or suspected components or structures in HE-stained sections were further determined in histological special stains or IF. By the technique, staining processing was videoed and made a backup for off-site pathologists, which facilitates tele-consultation or -education in current digital pathology. Mistakes, which might occur during the staining process, can be immediately found and amended accordingly. With the technique, a single section can provide much more information than the traditional stained counterpart. The staining mode bears great potential to become a common supplementary tool for traditional histopathology.

Definition of a sectioning plane and place for a section containing hoped-for regions using a spare counterpart specimen

Histological examination of targets in regions of interest in histological sections is one of the most frequently used tools in biomedical research. However, it is a technical challenge to secure a multitarget section for inspection of the structure’s mutual relationship of targets or a longitudinally filamentous- or tubular-formed tissue section for visitation of the overall morphological features. We present a method with a specified cutting plane and place, allowing researchers to cut directly at the multitarget centers accurately and quickly. The method is proven to be reliable with high accuracy and reproducibility and a low coefficient of variation, testing on repeat experiments of three target’s position-known models. With this method, we successfully yielded single sections containing whole intraorbital optical nerves, three aortic valves, or whole thoracic tracheas in their central positions. The adjoined custom-made tools used in the study, such as various tissue-specific formulated calibrated trimming and embedding guides, an organ-shaped cavity plaster mold, and a two-time embedding technique for optimal and identical trimming or embedding, also bear great potential to become a common supplemental tool for traditional histology and may contribute to the reduction of the labor, and the number of animals needed.

Development of heart failure in long-term survivors of childhood cancer: results from the cvss study

Background

Long-term survivors of childhood cancer (CCS) are at increased risk for cardiovascular sequelae, including heart failure (HF) as the largest non-malignant contributor to excess death. Yet, little is known about the risk factors, mechanisms of cardiac dysfunction and prevalence of different stages of HF in these patients.

Purpose

To investigate the development and prevalence of HF phenotypes in CCS compared to the general population.

Methods

The CVSS study is a prospective single-center cohort study investigating cardiovascular sequelae of CCS. Patients were eligible for the study when they were diagnosed with a neoplasia according to the International Classification of Childhood Cancer (ICCC 3) at an age prior to 15 years between 1980 and 1990, survived more than five years after initial cancer diagnosis and received antineoplastic treatment. Between 2013 and 2016, study individuals underwent a comprehensive, standardized clinical investigation in the CVSS cohort study including echocardiographic examination. HF was categorized as stages A to D according to current HF guidelines of the American Heart Association (AHA). A population-based sample free of cancer (age- and sex matched) serves as control group.

Results

From 1,002 individuals, all CCS with history of chemo- or radiotherapy and no subsequent neoplasia (n=877) were included (mean age 34.2 (±5.5) years, 44.7% (N=392) female). Age at diagnosis was 6.28 years (±4.24) and the mean interval from the date of diagnosis of cancer to the date of completion of baseline examination 28.5±3.2 years. Based on echocardiographic examination, clinical data and biomarker assessment, 26.6% of CCS were diagnosed with HF stage A, 21.1% with HF stage B and 2.1% with symptomatic HF, i.e. HF stage C/D. Importantly, prevalence of different HF stages varied strongly by specific tumor history. Compared to the population, the prevalence ratio (PR) was 1.16 [95% confidence interval 1.02/1.31] for stage A HF and 1.91 [1.63/2.23] for the composite of stage B to D HF in an age- and sex-adjusted Poisson regression model. Multivariable linear regression with the systolic marker left ventricular ejection fraction as dependent variable and adjustment for tumor entities, age, sex, and cardiovascular risk factors (CVRF) revealed a lower EF in patients with history of bone tumors (β −6.0 [−8.1/−3.0]), soft tissue sarcoma (β −2.2 [−4.1/−0.35]), leukemia (β −0.84 [−1.8/0.08]) and renal tumors (β −1.8 [−4.0/0.27]) compared to the population. In contrast, the same model for the diastolic marker E/E', showed an association only with CVRF, but not with tumor entities.

Conclusion

The prevalence of stage B to D HF was significantly higher among long-term CCS in the 3rd to 5th age decade compared to the population and varied strongly by tumor entity. Systolic dysfunction was primarily associated with history of tumor entities, whereas diastolic dysfunction was associated with the higher burden of CVRF in CCS.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study is funded by the Deutsche Forschungsgemeinschaft (DFG) (SP 1381/2-1&2, FA 1038/2-1&2, WI 3881/2-1&2)

Prevalence and outcome of cardiac amyloidosis in an all-comer population of patients with non-ischaemic heart failure

Background

Cardiac amyloidosis (CA) is increasingly recognized as an underlying cause of heart failure with preserved ejection fraction (HFpEF), associated with high morbidity and mortality. However, most studies, solely investigated the prevalence of CA in special subgroups including HFpEF and severe aortic valve disease.

Purpose

With the present study we sought to investigate prevalence of different phenotypes of CA in an all comer-population of patients with non-ischaemic heart failure (HF) and to analyze the impact of CA on all-cause mortality.

Methods

The My Biopsy HF-Study (German clinical trials register number: 22178) is a retrospective monocentric study investigating the underlying etiology of HF in an all-comer population of patients with HF of unknown etiology. Patients presenting with symptoms of HF at the University Medical Centre between 14/10/2012 and 01/03/2021, who underwent endomyocardial biopsy (EMB) were enrolled in the present study. Ischaemic HF and valvular HF were ruled out prior to EMB. Specimens were sent for further examination to a specialized laboratory approved by the Food and Drug Administration

Results

Between October 2012 and March 2021, 767 patients (71.6% men) with HF of unknown etiology were included. Mean age at the time of presentation was 55.4 years (±14.4). Altogether, 72.5% of the patients presented with HF with reduced ejection fraction (HFrEF), 7.1% were diagnosed with HF with mid-range ejection fraction (HFmrEF) and 20.4% with HFpEF. Based on histological examination and genotyping, CA was diagnosed in 44 (5.7%) patients (immunglobulin light chain [AL] CA: 15 patients; variant transthyretin [ATTRv] CA: 6 patients; wild type transthyretin [ATTRwt] CA: 21 patients; de novo CA: 2 patients). Patients with CA were older compared with patients without CA (69.4±11.4 vs. 54.1±14.5; p<0.0001), had a higher prevalence of arterial hypertension (68.2% vs. 50.9%; p=0.045) and showed a better left ventricular ejection fraction based on echocardiographic examination (47.5% vs. 32.6%; p<0.0001). With respect to biomarker expression, levels of both brain natriuretic peptide and high-sensitive troponin I were significantly higher in patients without CA (BNP: 914.1 vs 612; p=0.01; troponin I: 812.8 vs. 171.7; p=0.006). In univariate logistic regression analysis CA was associated with a significant all-cause mortality (hazard ratio [HR] per unit increase [ui], 5.17, 95% CI, 2.93–9.08; p<0.0001), even after adjustment for classical cardiovascular risk factors (HRperui 3.12, 95% CI, 1.11–8.76; p=0.03) and comorbidities like chronic obstructive pulmonary disease, chronic kidney disease and stroke (HRperui 2.93, 95% CI, 1.2–7.15; p=0.018).

Conclusions

Among patients presenting with HF of unknown etiology, including patients with HFpEF, HFmrEF and HFrEF, cardiac amyloidosis is the underlying cause of HF in 5.7% of patients and is independently associated with all-cause mortality.

Funding Acknowledgement

Type of funding sources: None.

Impact of cardiac amyloidosis on outcomes of patients hospitalized with heart failure in Germany

Background

Amyloidosis is a multi-systemic disease resulting from deposition of misfolded proteins as insoluble fibrils in the interstitium of affected organs including the heart, subsequently leading to organ failure. Cardiac involvement is predominantly observed in light chain (AL) amyloidosis and wild-type transthyretin (ATTRwt) amyloidosis.

Purpose

We aimed to investigate prevalence and prognostic implications of cardiac amyloidosis of any etiology on outcomes of hospitalized patients with heart failure (HF) in Germany.

Methods

We analyzed data of the German nationwide inpatient sample (2005–2018) of patients hospitalized for HF (including myocarditis with HF and heart transplantation with HF). HF patients with amyloidosis (defined as cardiac amyloidosis [CA]) were compared with those HF patients without amyloidosis and impact of CA on outcomes was assessed (source: Research Data Center (RDC) of the Federal Statistical Office and the Statistical Offices of the federal states, DRG Statistics 2005–2018, and own calculations).

Results

During this fourteen-year observational period 5,478,835 hospitalizations of HF patients were analyzed. Amyloidosis was coded in 5,407 hospitalizations of HF patients (0.1%). Prevalence of CA was 1.87 hospitalizations per 100,000 German population. CA patients were younger (75.0 [IQR 67.0/80.0] vs. 79.0 [72.0–85.0] years, p<0.001), predominantly male (68.9%) and had a higher prevalence of cancer (14.8% vs. 3.6%, P<0.001) compared with HF without amyloidosis. Although patients without amyloidosis had a pronounced cardiovascular risk profile -especially arterial hypertension (45.4% vs. 35.6%; p<0.001) and diabetes mellitus (38.9% vs. 18.5%; p<0.001)- and a higher prevalence of concomitant coronary artery disease (40.5% vs. 34.5%; p<0.001) and chronic obstructive pulmonary disease (17.1% vs. 9.4%; p<0.001), adverse in-hospital events including necessity of transfusions of blood constituents (7.1% vs. 5.4%, p<0.001) and cardio-pulmonary resuscitation (CPR, 2.7% vs. 1.4%; p<0.001) were more frequent in CA. CA was independently associated with acute kidney failure (OR 1.40 [95% CI 1.28–1.52], p<0.001), CPR (OR 1.58 [95% CI 1.34–1.86], p<0.001), intracerebral bleeding (OR 3.13 [95% CI 1.68–5.83], p<0.001) and in-hospital mortality in the 6th and 8th decade of life (6thdecade: OR 1.40 [95% CI 1.01–1.94], p=0.042; 8thdecade: OR 1.18 [95% CI 1.03–1.35], p=0.02).

Conclusions

CA was identified as an independent risk factor for complications and in-hospital mortality in HF patients. Physicians should be aware of this issue concerning treatments and monitoring of CA-patients.

Funding Acknowledgement

Type of funding sources: None.

Histo-ELISA technique for quantification and localization of tissue components

A novel Histo-ELISA technique is intended to facilitate quantification of target tissue proteins in a tissue section and involves the selection of target regions in the tissue section, application of streptavidin-conjugated HRP (horseradish peroxidase), coupled with peroxidase substrate—TMB (3,3′,5,5′-tetramethylbenzidine), and staining dye evaluation with ELISA reader. The target protein content (weight per volume unit) was translated from optical densities by a reference standard curve, obtained via parallel staining of the targeted protein-coated slides. To validate the technique, we carried out quantifications of IgG extravasation in ischemic and nonischemic brain sections in a mouse stroke model. With those obtained data and the reference of immunohistochemistry scores assessed on the adjacent sections, accuracy, sensitivity, and precision for the technique were evaluated. For all evaluated parameters, Histo-ELISA performance was either comparable to or better than the standard immunohistochemistry. A comparison with the data from the repeated measurements yielded a rather low coefficient of variation. The results confirmed that the technique is a fairly reliable quantitative test with rather high sensitivity, accuracy, precision, and reproducibility for detecting target protein content in tissue sections and that its tissue distribution and related subsequent morphological changes can be observed at the same time.

Temporal trends, sex-differences and outcomes of patients hospitalized for heart failure in Germany

Background

Despite remarkable improvements in treatment of cardiovascular disease, heart failure (HF) is still characterized by a high mortality rate. Sex-specific differences in HF have been described, but underlying reasons are widely unexplored. Thus, we aimed to investigate sex differences of patients hospitalized for HF in a nationwide cohort.

Methods

The nationwide German inpatient sample (2005–2016) was used for this sex-specific analyses. Temporal trends on hospitalizations, mortality, and treatments were analyzed and independent predictors of adverse outcomes identified.

Results

The present analysis comprises 4,538,977 hospitalizations due to HF (52.0%women) in Germany (2005–2016). Although women were older (median 82 (IQR75–87) vs. 76 (69–82), P<0.001), coronary artery disease (CAD, 50.3% vs. 30.7%, P<0.001) was more prevalent in men, who were more often treated with PCI (3.4% vs. 1.4%, P<0.001) and implantable cardioverter-defibrillator (2.2% vs. 0.5%, P<0.001). In-hospital mortality was significantly lower in men than in women (8.9% vs. 10.2, P=0.001) and was reduced in patients who received PCI or implantation of an ICD.

While total numbers of hospitalizations between 2005 and 2016 increased in both men (β-estimate 7185.71 (95% CI 6502.23 to 7869.18), P<0.001) and women (β-estimate 5297.60 (95% CI 4557.37 to 6037.83), P<0.001) as well as almost all comorbid co-conditions, in-hospital mortality rate decreased more distinctly in women (β-estimate −0.41 (95% CI: −0.42 to −0.39), P<0.001) compared to men (β-estimate −0.29 (95% CI: −0.30 to −0.27), P<0.001).

Conclusions

Interventional treatments of HF were associated with improved outcomes and equally beneficial for both sexes. However, they were more often used in male HF patients, in which CAD is significantly more frequent than in female HF patients. This may explain the higher case fatality rate of HF in females.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Federal Ministry of Education and Research (BMBF)

Global longitudinal strain predicts outcome in chronic heart failure across American Heart Association stages: results from the MyoVasc study

Background

Global longitudinal strain (GLS) demonstrated a superior prognostic value over left ventricular ejection fraction (LVEF) in acute heart failure (HF). Its prognostic value across American Heart Association (AHA) stages of HF – especially under considering of conventional echocardiographic measures of systolic and diastolic function – has not yet been comprehensively evaluated.

Purpose

To evaluate the prognostic value of GLS for HF-specific outcome across AHA HF stages A to D.

Methods

Data from the MyoVasc-Study (n=3,289) were analysed. Comprehensive clinical phenotyping was performed during a five-hour investigation in a dedicated study centre. GLS was measured offline utilizing QLab 9.0.1 (PHILIPS, Germany) in participants presenting with sinus rhythm during echocardiography. Worsening of HF (comprising transition from asymptomatic to symptomatic HF, HF hospitalization, and cardiac death) was assessed during a structured follow-up with subsequent validation and adjudication of endpoints. AHA stages were defined according to current guidelines.

Results

Complete information on GLS was available in 2,400 participants of whom 2,186 categorized to AHA stage A to D were available for analysis. Overall, 434 individuals were classified as AHA stage A, 629 as stage B and 1,123 as stage C/D. Mean GLS increased across AHA stages of HF: it was lowest in stage A (−19.44±3.15%), −18.01±3.46% in stage B and highest in AHA stage C/D (−15.52±4.64%, P for trend <0.0001). During a follow-up period of 3.0 [1.3/4.0] years, GLS denoted an increased risk for worsening of HF after adjustment for age and sex (hazard ratio, HRGLS [per standard deviation (SD)] 1.97 [95% confidence interval 1.73/2.23], P<0.0001) in multivariable Cox regression analysis. After additional adjustment for cardiovascular risk factors, clinical profile, LVEF and E/E' ratio, GLS was the strongest echocardiographic predictor of worsening of HF (HRGLS [per SD] 1.47 [1.20/1.80], P=0.0002) in comparison to LVEF (HRLVEF [per SD] 1.23 [1.02/1.48], P=0.031) and E/E' ratio (HRE/E' [per SD] 1.12 [0.99/1.26], P=0.083). Interestingly, when stratifying for AHA stages, GLS denoted a similar increased risk for worsening of HF in individuals classified as AHA stage A/B (HRGLS [per SD] 1.63 [1.02/2.61], P=0.039) and in those classified as AHA stage C/D (HRGLS [per SD] 1.95 [1.65/2.29], P<0.0001) after adjustment for age and sex. For further evaluation, Cox regression models with interaction analysis indicated no significant interaction for (i) AHA stage A/B vs C/D (P=0.83) and (ii) NYHA functional class <II vs ≥II in individuals classified as AHA stage C/D (P=0.12).

Conclusions

GLS demonstrated a higher predictive value for worsening of HF than conventional echocardiographic measures of systolic and diastolic function. Interestingly, GLS indicated an increased risk for worsening of HF across AHA stages highlighting its potential value to advance risk prediction in chronic HF.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Center for Cardiovascular Research (DZHK), Center for Translational Vascular Biology (CTVB) of the University Medical Center of the Johannes Gutenberg-University Mainz

OS3.2 Relevant topics for brain tumor patients in the Distress Thermometer, first results of the HEAT study

BACKGROUND

Patient-centered assessments and disease-adjusted patient-reported outcome measures (PROMs) are crucial in neuro-oncology. The Distress Thermometer (DT) is a well-accepted screening tool for cancer patients including a numerical rating scale (1–10, cut-offs indicating relevant distress ≥4–6) and 40 items describing possible problem categories (emotional, social, physical, practical and spiritual). The aims of the first part of the “Adaption of the Distress Thermometer in patients with intracranial tumors” (HEAT) study were to evaluate the importance and relevance of items for brain tumor patients (BTP).

MATERIAL AND METHODS

The multicenter study included three University hospitals. After given informed consent patients were prospectively evaluated either during their hospital stay or in the outpatient setting using DT as well as the 40 item problem list. Clinical and demographic data were recorded. We performed an analysis regarding frequency of indicated topics and evaluated their relevance for patients’ psychosocial well-beings via Pearson correlations with the DT score.

RESULTS

Data of n = 670 patients were analyzed. Mean age was 52 years (SD = 14, range 18–81), most of the patients harbored WHO°I tumors (37%) and WHO°IV tumors (28%). Male to female ratio was 1:1, 17% were assessed preoperatively, 40% postoperatively and 43% during adjuvant therapy or follow-up. 14% of the patients faced a tumor recurrence at assessment. Mean score of DT was 5.23 (SD = 2.9, range 0–10). Applying a cut-off score ≥ 4, 61% reported distress (≥ 5: 46% and ≥ 6: 37%). Regarding the relevance of the problem list for BTP, emotional problems (e. g., anxiety, depression) were most frequently reported. A total of 14/40 (35 %) of items were endorsed by less than 10% of patients. With exception of emotional problems all areas were reflected: practical problems (e. g., problems with child care or insurance), social problems (e. g., problems with children), spiritual concerns (e. g., loss of faith), and physical problems (e. g., breathing, fever). However, some of these rarely reported problems were of relevance for patients’ psychosocial well-being as indicated by significant correlations between the respective item and the DT score. This was, for example, the case for problems with childcare (r = .106; p < .01) or breathing (r = .125; p = .001).

CONCLUSION

Tools developed for cancer patients do not yet perfectly reflect all needs of BTP. Based on our data, we suggest further adjustments of available tools. Yet, it should be taken into account that subgroups of BTP may require different problem lists in the DT, as we observed some topics (e.g. breathing) probably be related to BTP under chemotherapy or steroids only. Moreover, our data require cross-cultural validation as especially results regarding practical problems and insurance might differ in cultures with different social security systems.

Plasma total prion protein as a potential biomarker for neurodegenerative dementia: diagnostic accuracy in the spectrum of prion diseases

AIMS

In the search for blood-based biomarkers of neurodegenerative diseases, we characterized the concentration of total prion protein (t-PrP) in the plasma of neurodegenerative dementias. We aimed to assess its accuracy in this differential diagnostic context.

METHODS

Plasma t-PrP was measured in 520 individuals including healthy controls (HC) and patients diagnosed with neurological disease control (ND), Alzheimer's disease (AD), sporadic Creutzfeldt-Jakob disease (sCJD), frontotemporal dementia (FTD), Lewy body dementia (LBD) and vascular dementia (VaD). Additionally, t-PrP was quantified in genetic prion diseases and iatrogenic CJD. The accuracy of t-PrP discriminating the diagnostic groups was evaluated and correlated with demographic, genetic and clinical data in prion diseases. Markers of blood-brain barrier impairment were investigated in sCJD brains.

RESULTS

Compared to HC and ND, elevated plasma t-PrP concentrations were detected in sCJD, followed by FTD, AD, VaD and LBD. In sCJD, t-PrP was associated neither with age nor sex, but with codon 129 PRNP genotype. Plasma t-PrP concentrations correlated with cerebrospinal fluid (CSF) markers of neuro-axonal damage, but not with CSF t-PrP. In genetic prion diseases, plasma t-PrP was elevated in all type of mutations investigated. In sCJD brain tissue, extravasation of immunoglobulin G and the presence of swollen astrocytic end-feet around the vessels suggested leakage of blood-brain barrier as a potential source of increased plasma t-PrP.

CONCLUSIONS

Plasma t-PrP is elevated in prion diseases regardless of aetiology. This pilot study opens the possibility to consider plasma t-PrP as a promising blood-based biomarker in the diagnostic of prion disease.

The GPVI-Fc fusion protein Revacept reduces thrombus formation and improves vascular dysfunction in atherosclerosis without any impact on bleeding times

Aims

Glycoprotein VI (GPVI) is a key platelet receptor which mediates plaque-induced platelet activation and consecutive atherothrombosis, but GPVI is also involved in platelet-mediated atheroprogression. Therefore, interference in GPVI-mediated platelet activation has the potential to combine short-term and long-term beneficial effects, specificity and safety especially regarding bleeding complications.

Methods and Results

We investigated the effects of the soluble dimeric GPVI receptor fusion protein, Revacept, an antagonist of collagen-mediated platelet activation, in an animal model of atherosclerosis: twenty week old rabbits, which had been fed on a cholesterol-rich diet for 8 weeks, received Revacept (8 mg/kg) or control twice weekly for 4 weeks. Pharmacokinetics indicated a slight accumulation of the drug in the serum after repeated dosing of Revacept for 3 weeks. A significant improvement of endothelial dysfunction after 0.06 and 0.6 µg/min acetylcholine and a significant decrease of vessel wall thickening were found after Revacept treatment. Accordingly, aortic vessel weight was reduced, and plaque sizes, macrophage and T-cell invasion tended to be reduced in histological evaluations. Bleeding time was determined after tail clipping in mice. Revacept alone or in combination with widely used anti-platelet drugs revealed a high safety margin with no prolongation of bleeding times.

Conclusion

Repeated doses of Revacept led to a significant improvement of endothelial dysfunction and vascular morphology in atherosclerotic rabbits. Furthermore, no influence of Revacept on bleeding time alone or in combinations with various anti-platelet drugs was found in mice. Thus, the inhibition of collagen-mediated platelet interaction with the atherosclerotic endothelium by Revacept exerts beneficial effects on morphology and vascular function in vivo and seems to have a wide therapeutic window without influencing the bleeding time.

The GPVI-Fc fusion protein Revacept improves cerebral infarct volume and functional outcome in stroke

OBJECTIVES

We examined the effect of Revacept, an Fc fusion protein which is specifically linked to the extracellular domain of glycoprotein VI (GPVI), on thrombus formation after vessel wall injury and on experimental stroke in mice.

BACKGROUND

Several antiplatelet drugs for the treatment of myocardial infarction or ischemic stroke with potent anti-ischemic effects have been developed, but all incur a significant risk of bleeding.

METHODS

Platelet adhesion and thrombus formation after endothelial injury was monitored in the carotid artery by intra-vital fluorescence microscopy. The morphological and clinical consequences of stroke were investigated in a mouse model with a one hour-occlusion of the middle cerebral artery.

RESULTS

Thrombus formation was significantly decreased after endothelial injury by 1 mg/kg Revacept i.v., compared to Fc only. 1 mg/kg Revacept i.v. applied in mice with ischemic stroke immediately before reperfusion significantly improved functional outcome, cerebral infarct size and edema compared to Fc only. Also treatment with 10 mg/kg rtPA was effective, and functional outcome was similar in both treatment groups. The combination of Revacept with rtPA leads to increased reperfusion compared to treatment with either agent alone. In contrast to rtPA, however, there were no signs of increased intracranial bleeding with Revacept. Both rtPA and Revacept improved survival after stroke compared to placebo treatment. Revacept and vWF bind to collagen and Revacept competitively prevented the binding of vWF to collagen.

CONCLUSIONS

Revacept reduces arterial thrombus formation, reduces cerebral infarct size and edema after ischemic stroke, improves functional and prognostic outcome without intracranial bleeding. Revacept not only prevents GPVI-mediated, but probably also vWF-mediated platelet adhesion and aggregate formation. Therefore Revacept might be a potent and safe tool to treat ischemic complications of stroke.

[Minimally invasive retrograde drilling of osteochondral lesions of the femur using an arthroscopic drill guide]

OBJECTIVE

Retrograde drilling for penetration of subchondral sclerotic bone in osteochondrosis dissecans (OCD) of the femoral condyle with preserved cartilage integrity. Hereby, revascularization of the OCD and immigration of bone marrow cells to achieve stable reintegration of the OCD into the surrounding subchondral bone.

INDICATIONS

Stable juvenile and adult osteochondrosis dissecans (stage I-II of the International Cartilage Repair Society (ICRS) classification) of the medial and lateral femoral condyle with an intact articular surface and surrounding sclerosis zone, which is visible in the x-ray.

CONTRAINDICATIONS

OCD stage III-IV of the ICRS grading scale. Relative contraindication: preceding retrograde drilling.

SURGICAL TECHNIQUE

Arthroscopic inspection and palpation of the cartilage defect. Minimal incision over the M. vastus medialis (when the defect is located in the medial condyle) or the M. vastus lateralis (when the defect is located in the medial condyle). Preparation and dissection of the fascia of the vastus muscle. Insertion of retractors underneath the vastus muscle to expose the metaphysis of the distal femur. Intraarticular positioning of the arthroscopic drill guide, placement of the wire guide and a Kirschner(K) wire on the femur metaphysis and retrograde drilling with a 2.0-2.2 mm K wire under radiographic visualization. Length measurement of the intraosseous wire distance. Switch the guide mechanism to a multiple hole drill guide and, depending on the defect size, insertion of a further 7-10 K wires of same thickness and defined length.

POSTOPERATIVE MANAGEMENT

Sterile bandage and slightly compressive dressing. Continuous active and passive knee motion. Weight bearing of 20 kg for 6 weeks, with subsequent transition to continuous weight bearing. Radiographic controls at 6 and 12 weeks postoperatively. In case of a persistent sclerosis zone in the control x-ray or clinical abnormalities, control MRI is indicated.

RESULTS

A total of 55 patients with a mean age of 19.6 years were treated using the described technique: 49 patients (89.1%), and 54 knees respectively (35 juvenile OCD, 19 adult OCD), were seen with a mean follow-up of 37.9 months. An improvement was observed in 81.6% of the knees using the radiographic score, i.e., a mean improvement of 1.13 of the radiographic score published by Rodegerdts and Gleissner (preoperative 3.04 vs. postoperative 1.91). Juvenile OCD showed better radiographic results overall (88.2% healing) than adult OCD (66.7% healing).

Distress in patients with newly diagnosed brain tumours

OBJECTIVE

Patients with intracranial tumours often suffer from clinically relevant psychological distress. However, levels of distress and contributing factors have not been systematically evaluated for the early course of the disease. Using the National Comprehensive Cancer Network's Distress Thermometer (DT), we evaluated the extent and sources of distress within a population of patients with intracranial neoplasms.

METHODS

One hundred and fifty-nine patients were included who underwent craniotomy for newly diagnosed intracranial tumours at our department. All patients completed the DT questionnaire, a single-item 11-point visual analogue scale measuring psychological distress. The appendant problem list (PL) consists of 40 items representing problems commonly experienced by cancer patients. Patients were asked to mark any experienced sources of distress.

RESULTS

Percentage of patients suffering from relevant distress was 48.4% (cut-off ≥6). DT-scores were significantly associated with depression and anxiety as well as reported number of concerns. On average, patients reported 6.9 sources of cancer-related distress. Objective medical data (e.g. tumour stage) as well as sociodemographic data (e.g. gender, IQ) were not associated with psychological distress at this early phase.

CONCLUSIONS

Prevalence of elevated distress is high shortly after primary neurosurgical treatment in patients with intracranial tumours and cannot be predicted by objective data. As a consequence, sources of distress can and should be routinely assessed and targeted in these individuals in this particular period. Further studies are needed to help to identify patients who are at risk of suffering from long-term emotional distress in order to enable targeted psychosocial intervention.

[Perioperative pain therapy in interventions for elbow stiffness]

Conservative treatment and surgical release of a stiff elbow requires correct pain management which should be oriented to the individual needs of the patient. Regional anesthesia in combination with opioids is necessary postoperatively to obtain sufficient pain relief. There is a need for prospective randomized studies to develop an optimal pain therapy concept following operations for elbow stiffness.

[Elevated postoperative pain levels following orthopedic surgery. Depression as a strong predictor]

The aim of this study was to examine whether depression is a strong predictor of elevated postoperative pain levels following orthopedic surgery and whether the implementation of standardized pain management is more beneficial for patients with depression. We performed a non-randomized, prospective study with two different groups of patients who underwent orthopedic surgery. Group 1 (n=249) received non-standardized pain therapy whereas group 2 (n = 243) was treated with a standardized pain management concept. Effects of the treatment were monitored with a VAS-based pain assessment protocol. Depression was measured preoperatively with the self-reported Patient Health Questionnaire (PHQ-9). Patients with the probable diagnosis of a current episode of major depression showed significantly higher postoperative pain than patients without a depressive episode. On the other hand, patients with depression benefited from the implementation of standardized pain management. Our data suggest a predictive value of depression for severe postoperative pain. Patients with depression benefited from standardized postoperative pain therapy, but were still suffering from significantly higher postoperative pain.

[Implementation of standardized postoperative pain therapy for orthopaedic patients. Comparison between unsystematic and standardized pain therapy]

BACKGROUND

The painless clinic and postoperative pain therapy are currently major issues in the management of surgical procedures. The aim of this study was to evaluate the benefit of a standardized pain therapy on the postoperative pain level after orthopaedic procedures.

PATIENTS AND METHODS

We investigated two different groups of patients who underwent an orthopaedic surgical procedure. Group 1 (n = 249) received a pain therapy which was based on an individual and surgery-dependent concept whereas group 2 (n = 243) was treated with a standardized pain therapy concept. The effect of the treatment was monitored with a VAS-based protocol.

RESULTS

Up to day 9 after surgery there was a significant difference between the two groups in regard to the postoperative pain. The patients of group 2 had less pain but had more unwanted side effects caused by the pain therapy during the first 3 days after surgery. Mobility and mental disposition were positively affected.

CONCLUSION

The implementation of a standardized pain therapy is successful in reducing postoperative pain. Mobility and mental disposition are also influenced positively. As a consequence the incidence of unwanted side effects is rising.

Investigations of the potential risk factors associated with cases of bovine spongiform encephalopathy in Bavaria, Germany

In order to identify the management and feeding practices that might have contributed to the occurrence of bovine spongiform encephalopathy (BSE) in Bavaria, Germany, information from 110 dairy farms on which a case of BSE had been reported was compared with information derived from a questionnaire sent to approximately 10,000 Bavarian farms on which no case of BSE had been reported up to February 2003. Representative information was obtained from 4006 dairy farms. The results indicated that in comparison with these control farms a higher proportion of the BSE farms had also kept pigs or poultry, although the difference was not significant, and that a significantly higher proportion of the BSE farms had fed proprietary concentrates and/or milk replacers to their calves.

In situ Analysis of Coronary Terminal Arteriole Diameter Responses: Technical Report of a New Experimental Model

INTRODUCTION

To date, investigation of coronary arteriole vasomotor activity has been limited to arterioles >30- 40 microm. Here, we introduce a new experimental model to allow for in situ microscopy of terminal coronary arterioles.

METHODS

Rat hearts were perfused in a closed loop system (priming volume 20 ml) which was placed on a computer-controlled microscope stage. FITC-dextran and tetrodotoxin (TTX, 50 microM) were added. Tilting of the microscope by 90 degrees allowed for visual access to the ventricular surface. Arterioles were identified by the flow direction of fluorescent beads (1 microm). Images were recorded on video tape, and arteriole diameters were measured offline. Stability of the preparation and maintenance of coronary flow reserve were analyzed. Responses of coronary flow and arteriole diameters to the vasodilators papaverine and Na-nitroprusside were recorded.

RESULTS

In TTX-arrested control hearts coronary flow and terminal arteriole diameters were stable for 2 h. Administration of papaverine and Na-nitroprusside increased coronary flow from 6.4 +/- 0.7 to 13.3 +/- 1.3 ml/min, decreasing coronary resistance by 52 +/- 3%. Terminal coronary arteriole diameters increased from 12.0 +/- 0.9 to 13.6 +/- 1.0 microm, decreasing hindrance of this vessel segment by 45 +/- 11%.

CONCLUSION

Preservation of coronary terminal arteriolar tone and adequate responsiveness to vasodilators in the TTX-arrested isolated heart were demonstrated. Thus, this model may serve to complement our understanding of coronary microvascular control mechanisms by extending observations to the terminal arteriolar bed.

Relapse in the skull after myeloablative therapy for high-risk neuroblastoma

Patterns of relapse were determined for 20 high-risk neuroblastoma patients treated with chemotherapy, surgery, primary and metastatic site radiation (21 Gray), myeloablative chemotherapy, peripheral blood stem cell rescue, and 13-cis-retinoic acid. The median follow-up duration after transplant is 21 months (range, 8-34 months). The event-free survival and overall survival at 2 years were 45 and 75%, respectively. There were 2 primary site recurrences. Metastatic sites that became MIBG-scan negative on induction chemotherapy were not irradiated. Four patients relapsed in irradiated metastatic sites, 3 in the skull, 1 in the liver. Failure also occurred at 2 skull sites treated with chemotherapy only, and at 5 new sites: 1 skull, 2 distant lymph nodes, and 2 bones other than skull. Eight of 20 patients had skull metastasis at presentation; 6 were irradiated and 3 were controlled. Skull metastasis warrants more aggressive evaluation and treatment.

Inhibition of host cell apoptosis by Toxoplasma gondii is accompanied by reduced activation of the caspase cascade and alterations of poly(ADP-ribose) polymerase expression

The obligate intracellular protozoan parasite Toxoplasma gondii has been shown to protect different cell types from apoptosis induced by a variety of pro-apoptotic treatments. However, the precise cell biological mechanisms of this inhibition remained unknown. As shown in this study, apoptosis in human-derived HL-60 and U937 cells induced by treatment with actinomycin D or TNF-α in combination with cycloheximide, respectively, was indeed dose-dependently downregulated by prior infection with T. gondii, as determined by DNA fragmentation assays. Cleavage of caspase 3 and caspase 9 after treatment with pro-apoptotic stimuli was considerably diminished by T. gondii. Furthermore, release of mitochondrial cytochrome c during apoptosis in HL-60 cells was prevented by intracellular parasites and this was correlated with the absence of DNA strand breaks on the single cell level. Inhibition of cytochrome c release coincided with a twofold upregulation of Mcl-1 protein levels in HL-60 and U937 cells, while Bcl-2 expression did not increase after infection. Parasitic interference with the caspase cascade led to a reduced proteolytic cleavage of the nuclear target molecule protein kinase Cδ. In parallel, poly(ADP-ribose) polymerase protein levels were prominently downregulated by T. gondii, irrespective of whether HL-60 and U937 cells had been treated with pro-apototic stimuli or left untreated. However, poly(ADP-ribose) polymerase mRNA levels remained unchanged after infection as determined by RT-PCR analyses. These observations suggest that T. gondii has evolved different mechanisms that may contribute to downregulation of host cell apoptosis, namely inhibition of cytochrome c release and subsequent caspase activation as well as downregulation of poly(ADP-ribose) polymerase protein levels.

Are some memory deficits unique to lesions of the mammillary bodies?

The role of the mammillary bodies in human memory is still in debate. A recent model of human amnesia proposes similar functions for the mammillary bodies and the hippocampus. But the main evidence for this model comes from animal studies using the delayed non-matching to sample paradigm. We describe a patient who developed a severe memory impairment after surgical removal of a germinoma. Postsurgical high resolution MRI revealed bilaterally shrunken mammillary bodies and an infarct of the left mammillary body. There were no other relevant lesions. Neuropsychological testing showed mildly impaired frontal lobe functions (executive functions, working memory and word fluency), almost intact learning and recognition, but severely impaired free and delayed recall. Experimental investigations revealed a reduced but preserved release of proactive interference and a pronounced impairment of recency and source judgments. We conclude that the mammillary bodies do play a prominent role in human memory, although the role differs slightly from that of the hippocampus.

Invasion by Toxoplasma gondii protects human-derived HL-60 cells from actinomycin D-induced apoptosis

Intracellular microorganisms have to rely on the integrity of their host cells to persist. We, therefore, investigated the effect of infections with different Toxoplasma gondii strains on apoptosis of human-derived HL-60 cells at the single cell level. Infection with either mouse-avirulent (NTE strain) or virulent parasites (RH strain) did not induce apoptosis of HL-60 cells as compared to uninfected controls. In contrast, treatment with actinomycin D (act D) led to apoptosis in 15-25% of the cells. However, concomitant infection with T. gondii clearly abrogated act D-induced apoptosis. This was especially apparent in those host cells that were actually infected; in these parasite-positive cells the rate of apoptosis decreased by 82.8+/-4.3% (mean+/-SEM, P=0.017, Student's t-test) and 91.7+/-3.4% (P= 0.024) after infection with either the NTE or the RH strain, respectively. Inhibition of host cell apoptosis was similarly observed in cells which had been invaded by UV-irradiated, non-replicating parasites (P=0.001, Student's t-test). However, incubation with heat-killed parasites or T. gondii lysates did not abrogate act D-induced apoptosis. In conclusion, inhibition of apoptosis by living, but not necessarily replicating T. gondii may facilitate parasite survival and persistence within its host cell.

Toxoplasma gondii inhibits the in vitro induced apoptosis of HL-60 cells

The integrity of the host cell may represent an important prerequisite for the intracellular survival and development of obligate intracellular pathogens. In the present study, we investigated the influence of infections with the protozoan parasite Toxoplasma gondii on the rate of apoptosis in the human leukemia cell line HL-60. After infection with T. gondii tachyzoites of the strain NTE and in uninfected controls, less than 2% of the host cells showed typical signs of apoptosis, i.e. condensation of chromatin after staining with Hoechst 33258 or internucleosomal DNA fragmentation after agarose gel electrophoresis of genomic DNA. After treatment with 0.1 to 0.5 microg/ml actinomycin D for up to 16 hours, HL-60 cells considerably underwent apoptosis. However, this actinomycin D-induced apoptosis was clearly reduced after concomitant infection with T. gondii as shown by staining with Hoechst 33258 and by DNA fragmentation assay. Inhibition of apoptosis by the intracellular pathogen T. gondii might be recognized as an evasion mechanism that enables intracellular survival and establishes long-lasting persistence.

The use of immunomorphology to differentiate choroid plexus tumors from metastatic carcinomas

BACKGROUND

The histologic and immunohistologic differential diagnosis of choroid plexus papillomas/plexus carcinomas (PP/PC) versus metastatic carcinoma in the brain is problematic.

METHODS

Thirty-four choroid PP/PC from 28 patients, 5 normal choroid plexus, and 45 cerebral metastatic carcinomas were immunohistochemically examined with the monoclonal anti-epithelial noncytokeratin antibodies HEA 125 and Ber EP4 using the alkaline phosphatase anti-alkaline phosphatase (APAAP) method.

RESULTS

Normal choroid plexus epithelium was consistently negative. Sections from PP/PC of 3 of 28 patients demonstrated immunoreactivity for these antibodies. In contrast, 43 of 45 cerebral metastatic carcinomas displayed positive immunostaining for HEA 125, and 44 of these 45 carcinomas were positive for Ber EP4. Thus, sensitivity was higher for these antibodies than for the monoclonal anticytokeratin antibody KL1 (41/45). All three HEA 125/Ber EP4-positive PP/PC contained periodic acid-Schiff (PAS)-positive, tall columnar tumor cells. The intensively HEA 125, Ber EP4, and PAS-positive PP/PC were interpreted as possible transitional forms of the mucus-secreting and acinar PP/PC:

CONCLUSIONS

Despite this restriction, the authors proposed the application of HEA 125 and Ber EP4 as a reliable tool in the differential diagnosis of PP/PC versus metastatic carcinoma, especially in combination with glial fibrillary acid protein and transthyretin. Currently, all HEA 125/Ber EP4-positive PP/PC in patients older than 20 years proved to be metastatic carcinomas during their clinical course.

Dysembryoplastic neuroepithelial micro-tumor in a 75-year-old patient with long-standing epilepsy

Dysembryoplastic neuroepithelial tumors (DNT) are rare, cortically located neoplasma associated with intractable partial complex seizures. This entity was first described by Daumas-Duport et al. [1988], who also coined the term DNT. In that report, at the time of operation, the patients' ages ranged from 3 to 30 years and the duration of symptoms ranged from 2 to 18 years. In contrast, we observed a histologically comparable tumor in a 75-year-old female with a 60 year epilepsy history. Autopsy revealed an 8 mm large tumor in the right hippocampus. In view of the extremely prolonged course of the patient's symptoms and the complete lack of excessive cell proliferation, the differentiation of a genuine tumor versus a hamartoma remains equivocal.

Influence of preoperative dexamethasone therapy on proliferating cell nuclear antigen (PCNA) expression in comparison to other parameters in meningiomas

We conducted a trial in 42 benign and malignant meningiomas to assess a possible influence of preoperative dexamethasone therapy on mitotic index, labelling indices of proliferating cell nuclear antigen (PCNA), progesterone receptor, epidermal growth factor receptor (EGF-R), c-erbB-2 oncoprotein, cathepsin D, gamma-gamma enolase as well as the mean number of silver-stained nucleolar organizer region-associated proteins (AgNORs). Tumors with preceding dexamethasone therapy for more than 1 day display significantly less immunohistochemical staining for PCNA. A correlation between the labelling index of PCNA and the degree of malignancy could not be identified. There was no significant effect of preoperative dexamethasone therapy on the other parameters. Our data suggest that dexamethasone may selectively inhibit the expression of PCNA in the G1/S-phase of the cell cycle. Thus, we emphasize the necessity to heed factors, e.g. dexamethasone, which may affect the expression of proliferating markers.

Indirect evidence to suggest that prolactin mediates the adrenal action of haloperidol to stimulate aldosterone and corticosterone secretion in rats

The effect of dopamine-antagonists on steroid secretion has revealed conflicting results regarding the confirmation of in vivo findings in vitro. In order to discriminate in vivo systemic and local action of the dopamine-antagonist haloperidol (HAL) on aldosterone and corticosterone secretion, microdialysis of the adrenal cortex in conscious, freely moving rats was employed. The effects of 2.5 mg HAL ip or intraadrenal dialysis of 20 micrograms/ml HAL in rats with an intact pituitary gland on PRL, aldosterone, and corticosterone secretion were examined. Systemic HAL application resulted in a 40-fold increase in PRL secretion and stimulated aldosterone and corticosterone production significantly. In contrast, intraadrenal dialysis of HAL had no effect on the secretory pattern of PRL or either steroid hormone, indicating no direct drug action on cells of the rat adrenal cortex. Similarly, ip injection of 2.5 mg HAL in hypophysectomized rats did not alter PRL or steroid hormone levels. We conclude that the dopamine-antagonist HAL stimulates aldosterone and corticosterone secretion in rats through a pituitary factor, probably PRL, but not through direct effects at the adrenal cortex.

Melanoma-associated antigens in tumours of the nervous system: an immunohistochemical study with the monoclonal antibody HMB-45

The aim of this study was to determine the specificity and sensitivity of the commercially available, monoclonal anti-melanoma antibody HMB-45 in brain tumours and peripheral nerve sheath tumours. Hence, a series of 155 different non-melanotic tumours of the central and peripheral nervous system were examined immunohistochemically. The brain lesions consisted of primary tumours and metastases from various carcinomas. Twenty melanotic tumours (cerebral metastases of malignant melanomas, meningeal melanomatosis, meningeal melanocytomas) and dermal blue cell naevi served as controls. All melanotic tumours stained positive. Furthermore, a positive immunohistochemical reaction was observed in the following non-melanotic tumours: gliosarcomas, primitive neuroectodermal tumours, ependymoma, malignant schwannomas and different intracranial hamartomas. Two plasmacytomas and 4 metastatic carcinomas also revealed positive staining for HMB-45. Our results confirm the necessity for cautious interpretation of HMB-45 immunoreactivity as a tool in the immunohistochemical characterization of nervous system tumours.

Nucleotide sequence analysis of a 10.5 kbp HindIII fragment of fowlpox virus: relatedness to the central portion of the vaccinia virus HindIII D region

The nucleotide sequence of a 10465 bp HindIII genomic fragment from fowlpox virus (FPV) is presented. Analysis of the nucleotide sequence revealed 10 potential major open reading frames (ORFs). Five of these ORFs are predicted to encode polypeptides with significant homology to hypothetical polypeptides derived from nucleotide sequence analysis of the vaccinia virus (VV) HindIII D region. Interestingly, these homologous ORFs do not occur in the same tandem arrangement in the FPV genome as they do in the VV genome. These results are discussed.

Coexpression by vaccinia virus recombinants of equine herpesvirus 1 glycoproteins gp13 and gp14 results in potentiated immunity

The equine herpesvirus 1 glycoprotein 14 (EHV-1 gp14) gene was cloned, sequenced, and expressed by vaccinia virus recombinants. Recombinant virus vP613 elicited the production of EHV-1-neutralizing antibodies in guinea pigs and was effective in protecting hamsters from subsequent lethal EHV-1 challenge. Coexpression of EHV-1 gp14 in vaccinia virus recombinant vP634 along with EHV-1 gp13 (P. Guo, S. Goebel, S. Davis, M. E. Perkus, B. Languet, P. Desmettre, G. Allen, and E. Paoletti, J. Virol. 63:4189-4198, 1989) greatly enhanced the protective efficacy in the hamster challenge model over that obtained with single recombinants. The inoculum doses (log10) required for protection of 50% of hamsters were 6.1 (EHV-1 gp13), 5.2 (EHV-1 gp14), and less than 3.6 (vaccinia virus recombinant expressing both EHV-1 glycoproteins [gp13 and gp14]).

Newcastle disease virus fusion protein expressed in a fowlpox virus recombinant confers protection in chickens

A cDNA copy of the RNA encoding the fusion (F) protein of Newcastle disease virus (NDV) strain Texas, a velogenic strain of NDV, was obtained and the sequence was determined. The 1,792-base-pair sequence encodes a protein of 553 amino acids which has essential features previously established for the F protein of virulent NDV strains. These include the presence of three strongly hydrophobic regions and pairs of dibasic amino acids in the pentapeptide Arg-Arg-Gln-Arg-Arg preceding the putative cleavage site. When inserted into a fowlpox virus vector, a glycosylated protein was expressed and presented on the surface of infected chicken embryo fibroblast cells. The F protein expressed by the recombinant fowlpox virus was cleaved into two polypeptides. When inoculated into susceptible birds by a variety of routes, an immunological response was induced. Ocular or oral administration of the recombinant fowlpox virus gave partial protection, whereas both intramuscular and wing-web routes of inoculation gave complete protection after a single inoculation.

Expression in recombinant vaccinia virus of the equine herpesvirus 1 gene encoding glycoprotein gp13 and protection of immunized animals

The equine herpesvirus 1 (EHV-1) gene encoding glycoprotein 13 (gp13) was cloned into the hemagglutinin (HA) locus of vaccinia virus (Copenhagen strain). Expression of the gp13 gene was driven by the early/late vaccinia virus H6 promoter. Metabolically radiolabeled polypeptides of approximately 47 and 44 kilodaltons and 90 kilodaltons (glycosylated form) were precipitated with both polyclonal and gp13-specific monoclonal antibodies. Presentation of gp13 on the cytoplasmic membrane of cells infected with the recombinant gp13 vaccinia virus was demonstrated by immunofluorescence of unfixed cells. Inoculation of the recombinant gp13 vaccinia virus into guinea pigs induced neutralizing antibodies to both EHV-1 and vaccinia virus. Hamsters vaccinated with the recombinant gp13 vaccinia virus survived a lethal challenge with the hamster-adapted Kentucky strain of EHV-1. These results indicate that expression in vaccinia virus vectors of EHV-1 gp13, the glycoprotein homolog of herpes simplex virus gC-1 and gC-2, pseudorabies virus gIII, and the varicella-zoster virus gpV may provide useful vaccine candidates for equine herpesvirus infections.