Feasibility and safety values of activated clotting time-guided systemic heparinization in coil embolization for unruptured intracranial aneurysms

OBJECTIVE

This study aimed to evaluate the feasibility and safety values of activated clotting time (ACT)-guided systemic heparinization in reducing periprocedural thrombosis and bleeding complications during coil embolization of unruptured intracranial aneurysms.

METHODS

A total of 228 procedures performed on 213 patients between 2016 and 2021 were included in the retrospective analysis. The target ACT was set at 250 s. Logistic regression was performed to assess predictors for the occurrence of thrombosis and bleeding. Receiver operating characteristic (ROC) analyses were employed to determine the optimal cut-off values for ACT, heparinization, and procedure time.

RESULTS

Most (85.1%) of procedures were stent-assisted embolization. The mean baseline ACT was 128.8 ± 45.7 s. The mean ACT at 20 min after the initial intravenous heparin loading of 78.2 ± 18.8 IU/kg was 185 ± 46.4 s. The mean peak ACT was 255.6 ± 63.8 s with 51.3% (117 cases) achieving the target ACT level. Peak ACT was associated with symptomatic thrombosis (OR per second, 1.008; 95% CI, 1.000-1.016; P = 0.035) (cut-off value, 275 s; area under ROC (AUROC), 0.7624). Total administered heparin dose per body weight was negatively associated with symptomatic thrombosis (OR per IU/kg, 0.972; 95% CI, 0.949-0995; P = 0.018) (cut-off value, 294 IU/kg; AUROC, 0.7426) but positively associated with significant bleeding (OR, 1.008 per IU/kg; 95% CI, 1.005-1.012; P <0 .001) (cut-off value, 242 IU/kg; AUROC, 0.7391). Procedure time was significantly associated with symptomatic thrombosis (OR per minute, 1.05; 95% CI, 1.017-1.084; P value = 0.002) (cut-off value, 158 min; area under ROC, 0.8338).

CONCLUSION

This study demonstrated that ACT-guided systemic heparinization was feasible to achieve the target ACT value and proposes probable safety thresholds to prevent periprocedural complications through reducing procedure time during coil embolization of unruptured intracranial aneurysms in the stent era.

Predictors for intracerebral hemorrhage after intravenous or intraarterial recanalization in acute major cerebral artery occlusion in Korean patients

OBJECTIVE

To evaluate predictors for intracerebral hemorrhage (ICH) and 1-month mortality after intravenous (IV) or intraarterial (IA) recanalization therapy for major cerebral artery occlusion in Korean patients.

METHODS

From 2011 to 2015, we prospectively gathered data from consecutive patients treated with IV/IA recanalization within 8 h of symptoms in a single center. The effects of demographic, clinical, laboratory, and radiological factors on ICH within 2 weeks were assessed, as well as 1-month mortality.

RESULTS

From a total of 183 patients, symptomatic intracerebral hemorrhage (SICH) occurred in 32 patients (17.5%), and asymptomatic ICH occurred in 37 patients (20.2%). The mortality rate at 1 month in ICH patients was 37.7%. The international normalized ratio (INR) (OR, 4.9; 95% CI, 1.03-23.4; p = 0.046), glucose (OR, 1.119 per mmol/L; 95% CI, 1.015-1.233; p = 0.023), medium-volume infarct (15-69.9 mL) (OR, 2.62; 95% CI, 1.1-6.26; p = 0.03), large-volume infarct (≥70 mL) (OR, 5.54; 95% CI, 2.1-14.6; p = 0.001), and angioplasty or stenting (OR, 6.29; 95% CI, 1.71-23.22; p = 0.006) were predictors of any ICH. Hyperlipidemia or statin medication (OR, 4.17; 95% CI, 1.38-12.59; p = 0.011), INR (OR, 7.13; 95% CI, 0.94-54.22 p = 0.058), and large-volume infarct (≥70 mL) (OR, 7.96; 95% CI, 2.31-27.39; p = 0.001) were predictors of SICH. Hypertension (OR, 5.77; 95% CI, 1.43-23.3; p = 0.014), initial NIHSS score (OR, 1.09; 95% CI, 1.01-1.18; p = 0.27), and SICH (OR, 15.7; 95% CI, 4.04-61.08; p < 0.001) were predictors of 1-month mortality.

CONCLUSION

INR and glucose may be strong modifiable predictors of critical ICH leading to death after IV/IA recanalization therapy in acute cerebral artery occlusion.

Double-barreled IMA-M2 and STA-MCA bypass in severe stenosis of terminal internal carotid artery: three case reports

EC-IC bypasses have been performed to treat complex aneurysms or moyamoya disease or atherosclerotic steno-occlusive disease. We report the three cases that underwent EC-IC revascularization of the IMA-M2 bypass using the radial artery graft concurrently after the STA-MCA anastomosis to prevent potential ischemic damage during the operation and augment more flow in terminal internal carotid artery stenosis. All patients experienced neither perioperative complications nor further events for a 3-month follow-up. The double-barreled IMA-M2 and STA-MCA bypass is a good option for substantial amount of EC-IC revascularization with minimizing ischemic injury and maximizing flow amount in patients with severe hemodynamic compromise.

Abstract TP51: Comparison of Recanalization Rate Between Intravenous Actilyse and Intravenous Actilyse With Mechanical Thrombectomy in Larger Artery Occlusion Ischemic Stroke Patients

Background and Purpose: According to the guidelines for acute ischemic stroke treatment, intravenous tissue plasminogen activator (IV-tPA) administration is the first line treatment and intraarterial thrombolysis (IA-Tx) with retrieval stent is regarded as additional treatment. But recanalization rate of large artery intracranial occlusion disease (LAICOD) after IV-tPA is very low and inconsistent according to the reports. Authors tried to find out the early recanalization rate of IV-tPA in patients with LAICOD.

Methods: 278 with anterior circulation occlusion patients were included in this analysis. Brain CT-angiography (CTA) was an initial imaging study and acute stroke MRI was following after the IV-tPA. Recanalization rate was studied with initial CTA and followed MRA image. And other clinical outcomes were compared with IV-tPA, IA-Tx or perfusion/diffusion-mismatching (P/D-mismatching) or not.

Results: The overall recanalization rate of LAICOD after IV-tPA was 15.5% (43/278), 86.0% (86/100) in patients treated with IA-Tx after IV-tPA, and 78.7% (48/61) in IA-Tx without IV-tPA. In patients who underwent IA-Tx after IV-tPA, P/D-mismatching patients showed higher recanalization rate (88.2% = 67/76 vs. 66.7% = 16/27, p = 0.020), and higher incidence of favorable outcomes (63.2% = 48/76 vs. 12.5% = 3/27, p = 0.000) compared to P/D-matching patients.

Conclusion: This study suggests that recanalization rate after IV-tPA for the patients with acute ischemic stroke due to LAICOD is very low and IV-tPA before IA-Tx does not significantly influence on the neurologic outcomes and complication rates. Bridging treatment is effective, for stroke patient management, but authors would like to propose that IA-Tx might be applied as the first therapy option, just like in the management of acute myocardial infarction patients.

1423Adherence to triple component antihypertensive regimen is higher in single-pill combination than two-pill regimen: data from a randomized controlled trial using medication event monitoring system

Background

Simplicity of regimen is known to be an important determinant of medication adherence and using single-pill combination (SPC) in hypertension treatment resulted in better adherence and persistence than free-equivalent combination. However, this finding has been studied only in dual-component antihypertensive treatments and in observational studies using medication possession ratio as an index of adherence. Medication event monitoring system (MEMS) is considered to be the gold standard in estimating medication adherence.

Purpose

To investigate the superiority in adherence of triple-component SPC compared to equivalent two-pill regimen using MEMS

Methods

This is a multi-center open-label randomized controlled trial. Inclusion criteria were hypertensive patients whose clinic blood pressure is not adequately controlled (systolic >140 mmHg or diastolic >90 mmHg) with combination antihypertensive regimen comprising two of three classes (angiotensin receptor blocker, calcium channel blocker and thiazide diuretics) for at least 4 weeks. Eligible patients were randomized either to single-pill (triple-component SPC, olmesartan/amlodipine/ hydrochlorothiazide 20/5/12.5 mg) or two-pill (dual-component SPC + one free pill, olmesartan/hydrochlorothiazide 20/12.5 mg + amlodipine 5 mg) groups and maintained for 12 weeks. Medications were dispensed in MEMS. Primary outcomes were the difference of percentage of dose taken (PDT) and percentage of days with prescribed dose taken correctly (PDTc) between single- and two-pill therapy, calculated from MEMS data.

Results

From 8 hospitals, 146 hypertensive patients were randomized into single- and two-pill groups. Final analysis was done in 65 and 66 patients in each group from which adherence index could be obtained. Baseline clinical characteristics of the two groups were not different. The single-pill group had significantly higher PDT and PDTc compared to the two-pill group. (median (25–75 percentile) (%), PDT 95.1 (87.9 - 100.0) vs 91.2 (79.8 - 96.5); PDTc 93.1 (79.8 - 96.5) vs 91.3 (70.7 - 96.4), p = both 0.04, by Wilcoxon rank sum test)

Percent dose taken

Conclusion

Single-pill combination of triple-component antihypertensive regimen showed superior adherence compared to equivalent two-pill therapy. Reducing pill burden by using SPC is a relevant strategy to enhance the adherence to multi-drug antihypertensive therapy.

Acknowledgement/Funding

Daiichi-Sankyo

Two-photon absorption and nonlinear optical properties of octupolar molecules

Two-photon absorption (TPA) cross sections of four representative series of octupolar molecules are theoretically investigated. The general structure--TPA-property relationship is described by using the effective four-state valence-bond three-charge-transfer model. As the charge-transfer character of the ground electronic state increases due to the strong donors or acceptors, (i) the transition dipole matrix elements between the ground and 2-fold degenerate excited states increase, (ii) the energy gap decreases, and consequently (iii) the TPA transition amplitude monotonically increases. Thus, the design strategy to maximize the TPA cross section of the octupolar molecule is established. On the basis of the four-state model, the first hyperpolarizability of the octupolar molecule is found to be linearly proportional to the TPA cross section. This theoretical relationship is confirmed by using the ab initio calculation results. The Hammett correlation analysis of the TPA cross section and first hyperpolarizability is also presented.

Two photon absorption properties of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives

Two-photon absorption (TPA) properties of 1,3,5-tricyano-2,4,6-tris(styryl)benzene derivatives have been investigated. Comparison of the absorption and fluorescence spectra reveals that these compounds show large Stokes shifts, which increase gradually as the conjugation length increases. One-photon absorption and excitation spectra are similar except that the latter exhibit several peaks near lambda(max). It is also found that the one- and two-photon-induced fluorescence excitation spectra are quite similar, which indicates that the one- and two-photon allowed-excited states are the same. The peak TPA cross section values (delta(max)) measured with nanosecond pulses by the two-photon-induced fluorescence method are in the range (50-2620) x 10(-50) cm4 s/photon. The delta(max) value increases as the donor strength and conjugation length increase. A linear relationship is observed between delta(max) and beta, and this delta-beta relationship is found to serve as a useful synthetic strategy for the design of novel TPA dyes with the octupolar structure.

Group and strain-specific neutralization sites of infectious bursal disease virus defined with monoclonal antibodies

Two somatic cell hybridizations were performed utilizing splenocytes from mice immunized with one or more strains of infectious bursal disease virus (IBDV). Supernatants from hybridoma cell lines were initially screened by the enzyme-linked immunosorbent assay (ELISA) against multiple strains of IBDV. Cell lines that secreted antibodies with ELISA reactivity patterns of interest were cloned, and their monoclonal antibodies (MCAs) were subsequently tested in cross-virus-neutralization tests. Two of the nine MCAs selected exhibited strong neutralizing activity and precipitated IBDV antigens in agar gel precipitin tests as well. MCA B69 significantly neutralized only the cloned D78 strain of IBDV, whereas MCA R63 neutralized all IBDV strains (representing both serotype I and II viruses) against which it was tested. Results of competitive ELISAs that used the R63 and B69 MCAs showed that the two neutralization sites on the D78 strain were not overlapping.

A survey of the aerobic bacteria in the feces of captive raptors

Feces of 47 captive raptors belonging to the order Falconiformes or Strigiformes were cultured for bacteria. Gram-negative bacteria, which were cultured from the feces of 45 of the 47 raptors, were the most common isolates. A wide variety of species were identified, including a newly described genus (Moellerella wisconsensis), two newly described species (Escherichia fergusonii and Proteus penneri), and a member of a newly described enteric group (CDC Enteric group 41). Additional organisms identified that have not been reported in previous bacteriological surveys of raptors were Salmonella heidelberg, Salmonella braenderup, Morganella morganii, Yersinia ruckeri, Serratia spp., and Kluyvera sp. Escherichia coli, isolated from the feces of 42 of the 47 raptors, was the most frequently recovered. Streptococcus faecalis, the second most common isolate, was cultured from 30 birds. Several differences were observed between fecal bacteria isolated from raptors fed commercially prepared chicken and those isolated from raptors not fed chicken. The most obvious difference was that birds fed chicken had more varied gram-negative bacterial species and in greater numbers per fecal sample. The potential for the isolated bacteria from raptors as pathogens in humans and avian species is discussed.

A survey of aerobic bacteria and fungi in the feces of healthy psittacine birds

Fecal samples from 61 clinically healthy psittacine birds of a wide variety of species were cultured for bacteria and fungi. The most common bacterial isolates were gram-positive bacilli, which were recovered from 60 of the 61 birds. These organisms included Lactobacillus, Bacillus, Corynebacterium, and Streptomyces. Gram-positive cocci, cultured from the feces of 21 of the birds, included Staphylococcus epidermidis, Streptococcus spp., Aerococcus spp., and Micrococcus spp. Only 6 of the 61 psittaciformes yielded gram-negative bacteria, with Escherichia coli being the most frequent isolate. Gram-negative bacilli were recovered from 4 of the 31 privately owned birds and 2 of the 30 petshop birds sampled. In addition to the bacteria, Candida albicans, Cryptococcus laurentii, and Aspergillus sp. were isolated from 13 fecal cultures. Candida albicans was isolated exclusively from 5 petshop birds. The number of birds yielding Corynebacterium and gram-negative bacteria increased with age, whereas the number of birds yielding lactobacilli and yeasts decreased with age. The organisms isolated and their significance as potential pathogens in psittacine birds are discussed.

An immunoperoxidase monoclonal antibody stain for rapid diagnosis of infectious bursal disease

Cell smears of chicken-embryo-fibroblast (CEF) cultures and bursa of Fabricius from chickens experimentally infected with six different strains of infectious bursal disease virus (IBDV) were examined for the presence of IBDV by the avidin-biotin-peroxidase complex method of immunoperoxidase (IP) staining using a monoclonal antibody specific for IBDV designated BK70. IBDV of different strains and serotypes were readily detected by the IP method in cell smears prepared from infected CEF cultures and from bursas. Bursal cells were positive for IP stain in most of the infected bursas (87.5%), despite their mild IBD lesions. Positive IP staining of bursal smears was well correlated with the recovery of IBDV from the bursas and with IBD lesions in the bursas. IP stain with a monoclonal antibody (BK70) appeared potentially useful for rapid and definitive diagnosis of IBD.

Improved focus assay of reticuloendotheliosis virus in a quail fibroblast cell line (QT35)

Reticuloendotheliosis virus (REV) strains T and CS consistently induced focus formation in a quail fibroblast cell line designated QT35 that was maintained under agarose overlay following inoculation of REV. The foci were more distinct and better circumscribed than those that developed in QT35 cultures under fluid medium. The focus formation in QT35 cultures under agarose overlay was inhibited by REV antiserum, and there were a highly significant correlation (r = 0.966, P less than 0.005) and a linear relationship between the number of foci that developed and relative virus concentration inoculated. This provides a valid focus assay for REVs.

Cytopathic effects and focus formation by reticuloendotheliosis viruses in a quail fibroblast cell line

The T and CS (chick syncytial) strains of reticuloendotheliosis virus (REV) induced focus formation and cytonecrotic changes in a Japanese quail fibroblast cell line designated QT35. The focus was distinctive and readily discernible, consisting of rounded refractile and larger dark-appearing (syncytia) cells usually aggregated along the periphery of a hole within a focus. The foci and cytopathic effects induced by the two strains of REV were morphologically indistinguishable. The focus formation in QT35 cultures was inhibited by chicken antiserum against the homologous or heterologous strain of REV; the homologous antiserum induced a greater inhibition. The altered cells composed of focus exhibited cytoplasmic fluorescence when stained by an indirect fluorescent-antibody technique with either the homologous or heterologous anti-REV serum. When foci that developed in QT35 cultures maintained under fluid medium were enumerated 3 days postinoculation, there were a highly significant correlation (P less than 0.001) and a linear relationship between the number of foci developed and relative virus concentration inoculated, thus justifying the validity of focus assay of REV by this system. The QT35 cell line may provide a useful in vitro system for virological and serological studies of REV.

Marek's disease virus (MDV) antigens in the feather follicle epithelium: difference between oncogenic and nononcogenic MDV

Feather tips from chickens infected with oncogenic or nononcogenic Marek's disease virus (MDV) were individually tested for MDV antigens by the agar-gel-precipitin test to compare antigen contents of feather follicles infected with oncogenic or nononcogenic MDV. There was a significant difference between oncogenic and nononcogenic MDV in the development of MDV antigens in the feather follicle epithelium of infected chickens. Significantly more feather tips from chickens infected with oncogenic MDV were positive for MDV antigens, particularly at 3 and 6 weeks postinoculation, whereas the feather tips from those infected with nononcogenic MDV were rarely positive, whether tested with the homologous or heterologous anti-MDV serum. Such a difference was consistent in separate trials employing three different strains of chickens. Infectious cell-free MDV was extracted more frequently from the feather tips of chickens infected with oncogenic MDV than from those of birds infected with nononcogenic MDV, and the virus titers of extracted MDV were always numerically or statistically higher in birds infected with oncogenic MDV.

A simple in vitro differentiation between turkey herpesvirus and Marek's disease virus

The growth and plaque formation by turkey herpesvirus (HVT) amd Marek's disease herpesvirus (MDHV) were examined in QT35 cells, a continuous fibroblast cell line derived from chemically induced tumors of Japanese quail. HVT grew and formed plaques consistently in QT35 cells when inoculated with cell-culture-propagated virus or peripheral mononuclear leukocytes (PML) from chickens that had been inoculated with HVT. Both oncogenic and nononcogenic strains of MDHV, however, failed to grow and induced neither plaques nor cytopathic effects in QT35 cells, whether inoculated with cell-culture-grown virus or heavily infected PML. When PML from chickens infected with both HVT and MDHV were assayed, only HVT plaques had developed, despite the presence in the inocula of high levels of MDHV with less HVT. The QT35 cell line provides a simple in vitro system for differentiating between HVT and MDHV and for selective isolation and identification of HVT from chickens infected with both HVT and MDHV.

Effects of infectious bursal disease on Marek's disease vaccination: suppression of antiviral immune response

Studies were made to determine whether infectious bursal disease virus (IBDV) infection would affect the response of chickens to turkey herpesvirus (HVT) vaccination in the development and level of HVT viremia and virus-neutralizing (VN) antibodies to HVT. The HVT viremia in the vaccinated chickens was not affected by IBDV, whether IBDV was inoculated simultaneously with HVT vaccination at one day of age or whether it was inoculated 3 weeks postvaccination with HVT. However, VN antibody response to HVT was significantly suppressed (P less than 0.001) when vaccinated chickens were exposed to IBDV either at the time of vaccination or at 3 weeks postvaccination. Such immunosuppression by IBDV of VN antibody response to HVT vaccination may result in a reduced antiviral immunity against Marek's disease virus.

Infectious bursal disease virus: further characterization with evidence for a single-stranded RNA virus

Infectious bursal disease virus (IBDV) that had been adapted to grow and was then cloned in chick embryo fibroblast (CEF) cell culture was examined for its physicochemical properties, the cellular site of virus replication, and the nature of its viral RNA. The IBDV was an RNA virus, acid-stable, absolutely resistant to chloroform, and moderately thermolabile. It appeared to replicate only in the cytoplasm, as shown by virus-specific antigens restricted to the cytoplasm of infected cells. The viral RNA was composed of single-stranded RNA, as evidenced by flame-red fluorescence on acridine-orange staining and an absence of specific fluorescence in infected cells on immunofluorescent staining with antiserum specific for double-stranded RNA. The IBDV virion had a hexagonal outline with an average diameter of 62 nm and possessed a single layer of capsid composed of hollow capsomeres without envelope. The buoyant density as determined in a continuous sucrose gradient was 1.178 g/cm3. The IBDV was found to possess morphologial and physicochemical properties different from those of any established RNA virus group.

Effects of avian reovirus on Marek's disease (MD). I. Suppression of MD development

The effects of an avian reovirus on the development of acute Marek's disease (MD) were studied by exposing chickens to Reo-W isolant of avian reovirus before infecting them with an oncogenic MD herpesvirus (MDHV). Four separate trials were made in a similar manner, 2 trials with an experimental line of White Leghorn (WSU-VS) highly susceptible to MD, and 2 trials with a commercial strain of meat-type (C-MT) chicken. MD mortality and/or incidence of gross MD lesions were consistently reduced by preexposure to avian reovirus. The suppression was more apparent in the WSU-VS than in the C-MT birds, and appeared greater with exposure to reovirus via the respiratory route than with the alimentary route.

Growth of infectious bursal disease virus with plaque formation in chick embryo fibroblast cell culture

The WA69 isolant of infectious bursal disease virus (IBDV) induced cytopathic effects and plaque formation in chick embryo fibroblast (CEF) cultures after serial passages in embryonated eggs and then in CEF cultures. The plaque-forming agent was cloned (designated WA69 clone) and identified as IBDV on the basis of serologic response in inoculated birds and its antigenic relationship to other known IBDV isolants. The WA69 clone replicated rapidly in CEF cultures, reaching peak titers at 48 hours postinoculation, and the virus caused only minimal histologic lesions of the bursa when inoculated into 3-week-old chicks from a specific-pathogen-free flock. The growth of IBDV in CEF cultures with plaque formation may provide a simple in vitro system for virological and serological studies of IBDV.

An improved method for extracting cell-free herpesviruses of Marek's disease and turkeys from infected cell cultures

Sonic extraction of cell-free Marek's disease herpesvirus (MDHV) and turkey herpesvirus (HVT) from infected cell cultures was improved by incorporating sorbitol in the suspending media. Yields of cell-free virus of virulent MDHV were significantly increased with 10% sorbitol added to SPGA-EDTA buffer. Avirulent strains of MDHV and HVT were respectively readily extracted with SPGA-EDTA and SPGA as the suspending medium, and extraction of their cell-free viruses was moderately improved by adding sorbitol to the suspending medium.

Dual virus maturation of both pathogenic and apathogenic Marek's disease herpesvirus (MDHV) in the feather follicles of dually infected chickens

Infectious cell-free viruses of both pathogenic and apathogenic Marek's disease herpesvirus (MDHV) were detected in feather-tip extracts of chickens dually infected with both MDHV isolants either by inoculation or by contact exposure. This indicated concurrent viral maturation of both pathogenic and apathogenic MDHV isolants in the feather-follicle epithelium, resulting in possible double shedding of the two isolants.

Studies of turkey herpesvirus viremia in two strains of vaccinated chickens strain difference and effects of vaccine dose

Turkey herpesvirus (HVT) viremia was studied at 3-week intervals through 21 weeks of age in individual chickens of experimental (WSU-VS) and commercial strains (C-WL) of White Leghorns vaccinated with graded doses of HVT. HVT viremia was consistently detectable in all WSU-VS birds through 21 weeks postvaccination (PV) regardless of vaccine dose employed, whereas the viremia could not be detected in some of the C-WL birds 9 to 15 weeks PV and thereafter. C-WL birds that lost detectable viremia remained so up to 21 weeks PV, or returned to low levels of viremia which was followed in some birds again by no detectable viremia. Viremia titers were significantly lower in the C-WL than in the WSU-VS birds despite the same vaccination. Both strains of chickens exhibited significantly lower viremia titers when vaccinated with 240 plaqueforming units (PFU) than with 1,480 or 6,600 PFU of HVT, and other C-WL birds lost detectable viremia earlier and more frequently with smaller vaccine doses. This observation indicated a possible genetic difference between the two strains of chickens in susceptibility and viremic response to HVT as well as dose-dependence of HVT viremia.

Avian cell cultures grown in an open system (dishes) without CO2 incubator, and their use for virus cultivation

An organic buffer, N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid (HEPES), in a culture medium made it possible to culture chick embryo fibroblast (CEF), duck embryo fibroblast (DEF), and chick kidney (CK) cells in an open system (dishes) under incubation in a bacteriological incubator, requiring no CO2 incubation. CEF, DEF, and CK cells cultured with this system were suitable for cultivation of avain viruses such as Newcastle disease virus, CELO virus, Marek's disease virus, and turkey herpesvirus.

An adenovirus from a turkey pathogenic to both chicks and turkey poults

An adenovirus, designated T-75 isolant, was isolated from the cloacal swab of a clinically normal turkey, 13 weeks old. The T-75 isolant was identified as an adenovirus on the basis of physicochemical properties, cytopathology, and agar-gel precipitin test. Producing two-way cross-neutralization reactions with CELO virus, the isolant was classified as an avian adenovirus of serotype 1. The T-75 isolant was pathogenic to both chicks and turkey poults, causing hepatitis, respiratory disease, atrophy of the bursa of Fabricius, and/or growth depression of experimentally inoculated birds, varying with the host and route of inoculation.

Horizontal transmission of turkey herpesvirus to chickens. 5. Airborne transmission between chickens

Airborne transmission of turkey herpesvirus (HVT) between chickens was studied in two trials using an experimental line of White Leghorns. HVT either did not spread or spread poorly to chickens that had been exposed for 8 weeks to the exhaust air from a cage containing donor chickens inoculated with HVT at 8 weeks of age. There was no airborne transmission of HVT to chickens that had been exposed for 4 weeks. This study indicated a possible by an infrequent spread of HVT between chickens via airborne route.

Marek's disease vaccine breaks: differences in viremia of vaccinated chickens between those with and without Marek's disease

Viremia with turkey herpesvirus (HVT) and/or Marek's disease (MD) herpesvirus (MDHV) was examined in chickens from three different commercial flocks experiencing "vaccine breaks" following vaccination with HVT vaccine against MD. In all groups of sample chickens from the flocks, the incidence of detectable HVT viremia was significantly less in the MD-affected than in the healthy penmates, and incidence of MD was significantly higher in the birds without detectable HVT viremia than in the viremic penmates. The results suggest an association between HVT viremia and protection against MD development.

In vitro biological differences between the pathogenic and the apathogenic Marek's disease herpesvirus

When three pathogenic and four apathogenic isolants of Marek's disease herpesvirus (MDHV) were compared, the pathogenic isolants differed from the apathogenic isolants in their in vitro growth and sensitivity to plaque inhibition by dextran sulfate. Plaques by the pathogenic MDHV isolants were distinctively different in their morphology from those by the apathogenic isolants, the plaque difference being most pronounced in chick embryo fibroblase (CEF) and duck embryo fibroblast (DEF) cell cultures. The pathogenic isolants formed plaques similarly in both CEF and DEF cultures, whereas the apathogenic isolants did so readily in CEF cultures, but very poorly in DEF cultures. The pathogenic isolants replicated better in DEF than in CEF cultures, whereas the apathogenic isolants replicated better in CEF than in DEF cultures. The sensitivitty to plaque inhibition by dextran sulfate was greater for the apathogenic isolants than for the pathogenic isolants of MDHV.

A possible association between plaque type and pathogenicity of Marek's disease herpesvirus

Eighteen isolants of Marek's disease herpesvirus (MDHV) were examined for their plaque types in chicken embryo fibroblast cell cultures and their pathogenicity to an experimental line of White Leghorns highly susceptible to MD. Seven isolants (Id-1, GA, WSU-GF, and 4 field isolants) induced morphologically similar small-cell plaques (SC plaques) consisting of small round refractile cells, whereas 11 isolants (HN and 10 isolants from zoo birds) all induced large-cell plaques (LC plaques) containing large cells along with small refractile cells. The 7 SC plaque isolants all produced clinical MD with high incidences of gross MD tumors, while all 11 LC plaque isolants produced subclinical infection with only minimal histologic lesions. This observation strongly suggests a possible association between plaque type and pathogenicity of MDHV isolants.

Effects of IgY antibody on the development of Marek's disease

The effects of passive immunization with immunoglobulin Y (IgY) on the pathogenesis of Marek's disease (MD) were examined in an experimental line of White Leghorn chickens highly susceptible to MD. Purified IgY with anti-MDV antibody activity, when injected into chicks, delayed the development of MDV viremia and lesions until 9 days postinoculation (PI) with Marek's disease virus (MDV). The blastogenic response of spleen cells to concanavallin-A was depressed at 6 days PI in the birds without passive immunization, whereas it was not totally depressed until 17 days in birds passively immunized with IgY anti-MDV antibody.

Immunoglobulins and anti-Marek's disease virus antibody synthesis in chickens after passive immunization with immunoglobulin Y anti-Marek's disease virus antibody

The effect of passive immunization with immunoglobulin Y (IgY) antibody against Marek's disease virus (MDV) was examined in MDV-susceptible chickens. The production of IgY, immunoglobulin M, and probably also immunoglobulin A was depressed in passively immunized chickens when compared with that in MDV-exposed chickens which had not been given IgY anti-MDV antibody. In passively immunized chickens, the synthesis of immunoglobulin M and IgY anti-MDV antibodies in response to MDV infection also was delayed as determined by agar gel precipitin and indirect fluorescence antibody tests.

Effect of cyclophosphamide on the response of chickens to a virulent strain of Marek's disease virus

The effect of cyclophosphamide on the pathogenesis of Marek's disease was examined in a line of chickens which is relatively resistant to Marek's disease. The injection of cyclophosphamide into newly hatched chickens delayed and reduced viremia and also reduced the development of Marek's disease lesions until 2 weeks after exposure to Marek's disease virus. The data indicate that a population of T cells susceptible to infection with virus and possibly viral transformation is affected by cyclophosphamide.

Virologic and serologic studies of zoo birds for Marek's disease virus infection

One hundred and eleven zoo birds representing 49 species in 14 orders were examined for Marek's disease (MD) herpesvirus (MDHV) infection. MDHV was isolated from 10 birds, all belonging to genus Gallus. The precipitating antibodies against MDHV were demonstrated only in the Gallus birds, when 51 selected birds including 34 Galliformes and 17 other birds representing 12 species from nine orders were examined. The 10 MDHV isolates all induced morphologically similar plaques in cell cultures closely resembling those of HN strain, a low pathogenic isolate of MDHV. Six of the 10 isolates, when inoculated into an experimental line of chickens highly susceptible to MD, caused only a minimal degree of histologic lesions without causing clinical MD, gross MD lesions, or deaths from MD. Natural hosts of MD are probably Galliformes, primarily affecting Gallus and less often other genera of Galliformes.

Horizontal transmission of turkey herpesvirus to chickens. IV. Viral maturation in the feather follicle epithelium

An experimental line of White Leghorns (WSU-VS) and a commerical line inoculated with turkey herpesvirus (HVT) at 1 or 8 weeks old did not differ in the occurrence of infectious cell-free HVT in their feather-tip preparations (FT-HVT). The birds examined at 2 weeks postinoculation (PI) were always positive for FT-HVT regardless of age at virus inoculation, dose of HVT inoculated, or genetic line of chickens, whereas only a few were positive at 4 weeks and none at 6 weeks PI.

Viremic responses of genetically susceptible and resistant chickens to experimental infection with acute, mild, or both strains of Marek's disease herpesvirus

The development and persistence of viremia were followed in two lines of Single-Comb White Leghorns: one experimental line (WSU-VS) highly susceptible, and one commercial line (C-WL) relatively resistant to Marek's disease(MD). In the resistant C-WL chicken, viremia with a mild strain of MD herpesvirus (MDHV) persisted in all viremic birds through 8 weeks postinoculation (PI), while viremia with an acute strain of MDHV did not, resulting in a decrease in number of viremic birds after 2 weeks PI. In the susceptible WSU-VS chicken, viremia with acute MDHV persisted in all viremic birds whereas viremia with mild MDHV was detected in a decreasing number of birds after 6 weeks PI. The pattern of viremia observed in the dually infected groups simulated a combination of the responses of the two groups respectively inoculated with mild and acute MDHV. Whether inoculation was with acute MDHV alone, or together with mild MDHV, levels of viremia with acute MDHV were appreciably higher in the WSU-VS than in the C-WL chicken. In both lines, levels of viremia were higher with acute MDHV than with mild MDHV but viremia with acute MDHV could not be demonstrated in the C-WL bird at 6-8 weeks PI. Levels of viremia with mild MDHV were consistently and similarly low in both WSU-VS and C-WL chickens.

Horizontal transmission of turkey herpesvirus to chickens. 3. Transmission in three different lines of chickens

Horizontal transmission of turkey herpesvirus (HVT) was studied in three separate trials using three different lines of chickens in each trial. There was no horizontal spread of HVT to contact cagemates through 8 weeks regardless of the line of donor chickens, when inoculated subcutaneously with 9.2 times 10-3 plaque-forming units (PFU) of HVT at 1 week of age. The virus spread poorly to a few cagemates from an experimental line of White Leghorns (W.S.U.-V.S.), but not from a commercial line of White Leghorns (C.-W.L.) or meat-type (C.-M.T.) chickens, when inoculated with 9.4 times 10-4 PFU of HVT at 1 week of age. The virus spread readily to contact cagemates from W.S.U.-V.S. but not at all from C.-W.L. or C.-M.T. chickens when inoculated with 2 times 10-4 PFU of HVT at 8 weeks of age. The incidence among cagemates of contact infection by HVT appeared similar regardless of genetic lines. This observation indicated a difference among different genetic lines of chickens in the development and/or shedding of infectious HVT following virus inoculation.

Isolation and characterization of an isolate (HN) of Marek's disease virus with low pathogenicity

A cytopathic agent was isolated and characterized as an isolate of Marek's disease herpesvirus (MDHV) with low pathogenicity, and referred to as the HN isolate. This isolate of MDHV did not cause clinical Marek's disease (MD) or death in a highly susceptible line of chickens within 5 weeks after exposure. Gross lesions of limited extent were noted in a few of the inoculated birds. Microscopic nerve lesions in the inoculated and contact-infected birds were invariably minimal, closely resembling C-type MD lesions.