Newcastle disease virus in little owls (Athene noctua) and African penguins (Spheniscus demersus) in an Israeli zoo.

Newcastle disease is a contagious and often fatal disease, capable of affecting all species of birds. A velogenic Newcastle disease virus (vNDV) outbreak occurred in an Israeli zoo, in which Little owls (Athene noctua) and African penguins (Spheniscus demersus) were found positive for presence of NDV. Some of them have died. The diagnostic process included: post-mortem examination, histopathology, real-time RT-PCR assay, virus isolation, serology, intracerebral pathogenicity index and phylogenetic analysis. A vNDV was diagnosed and found to be closely related to isolates from vNDV outbreaks that occurred in commercial poultry flocks during 2011. All isolates were classified as lineage 5d.

Characterization of a Low Pathogenic Avian Influenza Virus (H6N1) Isolated from Turkeys.

An avian influenza virus (AIV), A/turkey/Israel/09 subtype H6N1, was isolated from turkey poults exhibiting typical pathology associated with AIV infection. The virus was characterized by RT-PCR using AIV subtype-specific primers and by the haemagglutination inhibition test using AIV subtype-specific antisera. The virus has an intravenous pathogenicity index of 0 and possessed a nucleotide sequence at the cleavage site of the hemagglutinin gene, PQIETR*GLF, associated with avian influenza viruses of low pathogenicity. Unlike the two previous H6N2 isolates originating from domestic ducks and mallard, the A/turkey/Israel/09 (H6N1) was isolated from turkeys. The gene sequences of the A/turkey/Israel/09 (H6N1) virus show divergence from the former Israeli H6 isolates.

Avian influenza virus H9N2 survival at different temperatures and pHs.

The H9N2 avian influenza virus (AIV) subtype has become endemic in Israel since its introduction in 2000. The disease has been economically damaging to the commercial poultry industry, in part because of the synergistic pathology of coinfection with other viral and/or bacterial pathogens. Avian influenza virus viability in the environment depends on the cumulative effects of chemical and physical factors, such as humidity, temperature, pH, salinity, and organic compounds, as well as differences in the virus itself. We sought to analyze the viability of AIV H9N2 strains at three temperatures (37, 20, and 4 C) and at 2 pHs (5.0 and 7.0). Our findings indicated that at 37 C AIV H9N2 isolate 1525 (subgroup IV) survived for a period of time 18 times shorter at 20 C, and 70 times shorter period at 4 C, as measured by a decrease in titer. In addition, the virus was sensitive to a lower pH (pH 5.0) with no detectable virus after 1 wk incubation at 20 C as compared to virus at pH 7.0, which was viable for at least 3 wk at that temperature. The temperature sensitivity of the virus corresponds to the occurrence of H9N2 outbreaks during the winter, and lower pH can greatly affect the viability of the virus.

Development of a real-time TaqMan RT-PCR assay for the detection of H9N2 avian influenza viruses.

Avian influenza viruses (AIVs) of the H9N2 subtype are a major economic problem in the poultry industry in Israel. Most field isolates from the last decade differ significantly from H9N2 isolates from Europe and the USA, rendering published detection methods inadequate. This study aimed to develop a real-time TaqMan((R)) RT-PCR assay, based on a conserved region in the HA9 gene. The assay was validated with viruses representing different genetic subtypes and other common avian pathogens, and was found specific to H9N2. The real-time RT-PCR assay was compared to RT-PCR, which is in routine diagnostic use. Real-time RT-PCR was found to be more sensitive than RT-PCR by 1.5-2.5 orders of magnitude when testing tracheal swabs directly and by 2-3 orders of magnitude allantoic fluid after AIV propagation in embryonated eggs. Sensitivity was quantified by using 10-fold dilutions of the H9-gene amplification fragment, and real-time RT-PCR was found to be 10(4)-fold more sensitive than RT-PCR. Clinical samples, which included tracheal and cloacal swabs, as well as allantoic fluid, were tested by both methods. By real-time RT-PCR 20% more positive H9N2 samples were detected than by RT-PCR. The real-time RT-PCR assay was found suitable for detection and epidemiological survey not only of Israeli H9N2 viruses, but also for isolates from other parts of the world.

Ethanol enhancement of the motor-stimulating effect of nicotine in the rat.

Although ethanol stimulates locomotion in mice, it has been difficult to demonstrate such an action in rats. In contrast, nicotine has been shown to enhance locomotion, including ipsiversive rotation in nigral-lesioned rats. We found no significant effect of ethanol alone on rat rotation at doses of 0.125, 0.50, 1.0, and 2.0 g/kg, IP, during a 30-min observation period. However, there was a dose-dependent effect of ethanol enhancing the rotation induced by nicotine (0.4 mg/kg, SC) given 30 min after the ethanol. The interaction of ethanol and nicotine on locomotion most likely involves the release of dopamine and may be related to the motor abnormalities sometimes seen clinically.

Route knowledge in different spatial frames of reference.

Orienting oneself in space requires establishing a correspondence between various spatial frames of reference (SFR) in which the same information about the environment can be encoded in different ways and formats. In this encoding process, one key point is the alignment of the SFRs, which may require additional operations such as a mental or real rotation. Three experiments were conducted to investigate the process of spatial orientation under aligned and misaligned conditions. Subjects were shown animated sequences of decision points perceived along a route (Experiments 1 and 2) or verbal route instructions (Experiment 3) to which they had to attribute a path on a map. The results showed that when the orientations of the map and the route were different (misalignment) both total time and errors increased. The route length (Experiment 1), and the need to reverse the direction of the path (reverse response condition in Experiments 2 and 3) also led to a decline in performance. In Experiment 3, the map-rotation strategy was found to be pertinent for solving misaligned spatial problems.

Action of nicotine on accumbens dopamine and attenuation with repeated administration.

The behavioral and physiological effects of repeated nicotine administration are complex; sedation and hypothermia are present early but become attenuated while locomotor activity increases. Maximal blood levels and behavioral changes occur within 10 min of s.c. injection. We examined the effects of 10 nicotine injections (0.8 mg/kg) in 14 days on the levels of brain amines following challenge with either saline or nicotine on the 15th day. Dopamine, DOPAC, HVA, 3-methoxytyramine, norepinephrine, 5-hydroxytyramine, and 5-HIAA were measured in the frontal cortex, olfactory tubercle, nucleus accumbens, caudate-putamen, substantia nigra and ventral tegmental area. Ten minutes after nicotine was given to rats that had previously received only saline the levels of dopamine and its metabolite DOPAC indicated an increase in dopamine turnover in the nucleus accumbens. Of the areas examined the accumbens was the most sensitive to nicotine, with few significant amine changes in other regions. Twenty-four hours after the last nicotine injection the levels of dopamine and its metabolites indicated a sustained decrease in dopamine turnover in the accumbens induced by repeated administration. Following repeated nicotine a nicotine challenge still induced an acute increase in dopamine turnover in the accumbens, but the response was less than in animals not previously given nicotine. The results confirm earlier studies indicating that the accumbens is a major site of nicotine action.

Acute reduction of brain substance P induced by nicotine.

Ten minutes after a single injection of 0.8 mg/kg nicotine SC (free base) the level of substance P-like immunoreactivity (SPLI) was reduced by 61-73% in rat caudate-putamen, nucleus accumbens, and olfactory tubercle, with smaller and not significant reductions in the frontal cortex, substantia nigra, and ventral tegmental area. The nicotinic receptor antagonist mecamylamine (1.0 mg/kg IP) prevented the reductions in SPLI. The rapidity and the degree of the changes in SPLI after nicotine exceed those previously reported for other agents and implicate substance P neurotransmission as a major component of nicotinic action.

Dopamine-like action of nicotine: lack of tolerance and reverse tolerance.

Rats with unilateral 6-hydroxydopamine lesions of the substantia nigra became briefly sedated and hypothermic after the acute injection of nicotine s.c. (0.4 or 0.8 mg/kg free base). When nicotine was repeated 5 days per week there was rapid tolerance for the sedation and slower tolerance for the hypothermia and the lesioned animals began to rotate ipsiversively after each injection. Stereotypic behavior was also noted. Rats injected with nicotine 5 days per week and nigrally lesioned on the 24th day rotated promptly on their first postoperative injection of nicotine. The nicotinic antagonist, mecamylamine (1.0 mg/kg i.p.), completely blocked the induced rotation. The appearance of rotation did not seem to depend on tolerance to sedation. The direction of rotation indicated enhancement of activity in the intact nigrostriatal system. However, 10 min after the acute injection of 0.8 mg/kg nicotine no change was found in the ratios of dopamine to its metabolites DOPAC and homovanillic acid in the substantia nigra, caudate-putamen, nucleus accumbens, olfactory tubercle, frontal cortex, or ventral tegmental area. Rats given 0.4 or 0.8 mg/kg nicotine 5 days per week and either lesioned prior to nicotine or lesioned during the third week rotated during the sixth week without any sign of tolerance. One day after the 30th injection in intact or lesioned rats the ratios of dopamine to its metabolites did not differ from those in saline controls on either the right or left side of any of the regions examined. There was no evidence of a change in dopamine metabolism after an acute challenge with nicotine or of a sustained change after repeated injection. The possibility remains that repeated nicotine modifies the dopaminergic response to nicotine without causing a sustained change in metabolism.

Chronic nicotine administration increases binding of [3H]domperidone in rat nucleus accumbens.

An apparent inverse relationship between smoking and Parkinson's disease prompted an investigation of the effect of chronic nicotine administration on dopaminergic and serotonergic receptors in rat brain. Nicotine, 0.8 mg/kg, was injected once daily, five times per week, for 6 weeks. In nucleus accumbens the Kd for [3H]domperidone was increased 2-4-fold, and the Bmax was increased 1.5-2-fold. No changes were observed in the binding of [3H]domperidone in caudate-putamen or in that of [3H]ketanserin in frontal cortex. It is concluded that chronic nicotine administration may have a suppressant effect on central nervous system release of dopamine that in pre-parkinsonian persons causes an aversion to the effects of smoking.

The influence of systemic factors on acrylamide-induced changes in brain, nerve, and other tissues.

In order to define the locus of acrylamide neurotoxicity, the effects of chronic intoxication (total dose 500 mg/kg) on cholinergic synthesis and transport, the Schwann cell-myelin complex, lysosomal activity, and several metabolic pathways were determined in rat sciatic nerve, spinal cord, and brain. No changes were found in hematological measures or in the levels of clinically important blood enzymes, indicating no major damage to other organs. The activities of choline acetyltransferase (ChAT), 2',3'-cyclic nucleotide phosphohydrolase, beta-glucuronidase, and lactate dehydrogenase were unaffected in acrylamide paralyzed animals, but creatine kinase (CK) decreased in sciatic nerve, muscle, and brain, particularly in animals dying of the intoxication. CK blood and the CK isoenzyme patterns in blood were unchanged. The synthesis of protein in brain and spinal cord (measured in vivo) were decreased in rats exposed to high-dose acrylamide. However, in brain and cord, CK decreased only after animals became systemically ill and suffered weight loss, with the lowest activities in those animals sick enough to die. The degree of stress to which the animals had been subjected was indicated by enlargement of the adrenal glands and decreased sulfolipid synthesis in the adrenals. Rats exposed to 25 mg/kg/day acrylamide to a total dose of 250 mg/kg developed leg weakness but not paralysis or weight loss and had a 25% decrease in CK only in the distal sciatic nerve. Because of the apparently stress-related or agonal loss of CK, no specific effect of acrylamide on the enzyme could be definitely demonstrated. Neither could the changes in protein synthesis be attributed solely to a direct effect of the toxin. These results illustrate the difficulties encountered in interpreting intoxication studies that produce systemic illness and support the suggestion that CK activity may be a useful marker of the severity and duration of the agonal state in studies of postmortem human brain.

Enzyme changes in axon, myelin, and Schwann cells in injured sciatic nerve.

Four enzymes related to specific cell functions were assayed in rat sciatic nerve injury by crush (cr) or crush and ligation (cr-lig) after 2, 7, and 15 days in situ. Enzyme activities in segments of sciatic nerve proximal and distal to the injury were compared to those in corresponding segments of the contralateral nerve. Choline acetyltransferase (CAT) activity in the distal portion decreased by 65% for cr and almost to zero for cr-lig by day 7, while in the proximal portions CAT decreased to 70% of control values by 7 days and to 50% at 15 days after cr-lig. The activity of the Schwann cell-myelin-associated enzyme 2',3'-cyclic nucleotide phosphohydrolase (CNP) decreased slowly distal to the injury. Distal to both types of injury the lysosomal enzyme beta-glucuronidase (GLR) increased six- to eightfold by 15 days. Proximal to injury GLR also increased (P cr X 2.5, P cr-lig X 5) but the peak proximally was attained by day 7. Despite interruption of axonally transported enzymes, the activities of the metabolic enzyme creatine kinase (CK) increased distal to injury apparently reflecting changes in the functions of the Schwann cells. The loss of metabolic enzymes from the axonal compartment may be completely obscured by reciprocal changes in the non-neuronal compartments if the activity is present in both compartments.

The activity of 2',3'-cyclic nucleotide 3'-phosphodiesterase in rat tissues.

The activity of the myelin-associated enzyme 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNP) was measured in 14 rat tissues and in subcellular fractions of rat liver by a sensitive fluorometric method, using cyclic NADP as substrate. CNP activity in brain (339 mumol/h/mg protein) was fourfold that of the sciatic nerve. The activities in tissues outside the nervous system ranged from a low of 0.42 mumol/h/mg protein in the unwashed red blood cell to a high of 9.96 in the spleen. The activity was highest in tissues containing cells with membranes capable of undergoing transformation and elaboration (spleen and thymus) and low in those in which the cell membranes are morphologically stable (muscle and red cell). The enzyme was found in all major liver subfractions, with the highest activities in the microsomal and nuclear fractions. Despite the large difference in the maximal velocities of CNP in brain and liver, the affinity of the liver enzyme for the substrate (km) was similar to that of brain enzyme. Brain CNP was stable over a 48-h postmortem period.

Effects of anti-white matter serum on myelin and lipid synthesis in brain prisms.

Tissue prisms prepared by choping whole mouse brain maintained respiratory capacity and ultrastructural integrity of 3 h in vitro. Normal rabbit serum (ca. 25%) caused no morphological change but inhibited the synthesis of galactolipids by the prisms. Heating the serum abolished the inhibition. Complement containing anti-white matter rabbit serum destroyed myelin and inhibited galactolipid synthesis to a greater degree than did normal serum. Structures other than myelin were unaffected by the antiserum. Incubation in the presence of heated anti-white matter serum eliminated the myelin destruction but resulted in specific morphological changes characterized by the doubling of the myelin lamellae at the intraperiod line. Immunoperoxidase studies suggest specific binding of immunoglobulin to components of myelin located at the intraperiod lone. These changes were similar to those found in organotypic cultures. Heated antiserum did not inhibit galactolipid synthesis but addition of complement (normal guinea pig serum) to the heated antiserum restored only that portion of the inhibition which exceeded that caused by normal serum. Heat labile factors in normal rabbit serum which inhibit myelin lipid synthesis in the prisms must be corrected for in studies in which the heating of serum is used to demonstrate that the effect is complement dependent. The prism system is simpler than that of organotypic cultures and may be useful in the study of myelinotoxic factors.

Hydrogen-induced microelectronic capacitor failure in pacemakers.

Ceramic chip capacitors used in hybrid microelectronics for cardiac pacemakers are usually highly reliable. However, under certain conditions of capacitor construction, capacitor materials, mounting techniques, and environmental conditions, high failure rates may occur. A specific example is presented in which a ceramic capacitor used in an implanted pacemaker delaminated and failed approximately 30 days after being implanted. The failed capacitor caused a pulse rate rise, but due to circuit design techniques, the rate increase was limited to an acceptable value. The capacitor that failed was from an isolated lot of capacitors that was manufactured using pure palladium plates. The circuit containing this capacitor was hermetically sealed within a titanium case by welding. During the welding, a small amount of hydrogen was released from the titanium which, over a period of 2 to 4 weeks, was absorbed by the palladium plates in the capacitor. By absorbing the hydrogen, the palladium plates exhibit a volumetric expansion of sufficient magnitude to crack and delaminate the capacitor to the point of failure. Subsequently, the recurrence of this failure mode has been avoided by using capacitors containing special palladium alloys that cannot absorb hydrogen. This phenomenon is of interest to pacemaker designers since mercury batteries used in conventional pacemakers generate large amounts of hydrogen and potentially may be responsible for complications when used in conjunction with capacitors containing palladium.

Myocardial perfusion imaging with 99m-Tc or 113m-In macroaggregated albumin: correlation of the perfusion image with clinical, angiographic, surgical, and histologic findings.

Scintillation camera myocardial perfusion images were performed in 77 patients with proved or suspected ischemic heart disease following the intracoronary injection of 1.5 mCi 99m-Tc or 113m-In macroaggregated albumin. Perfusion images were classified as normal (36) or abnormal (41), and the location of abnormality was noted. Thirty-seven out of 41 patients with abnormal images had prior myocardial infarction based on history (30), ECG Q-waves (27), local contraction pattern abnormality (23), or direct surgical (9) or histologic (4) inspection, either singly or in combination. Three out of five patients with pre-infarction angina had image defects-none had evidence of infarction by ECG, ventriculogram, or surgical inspection. Coronary artery stenosis correlated with image defects to the extent that myocardial infarction was associated; 28 out of 29 patients with total occlusions and other evidence of infarction had image defects, four patients with complete occlusions but without other evidence of infarction had normal images. We conclude that, excepting patients with pre-infarction angina, this technique is more sensitive and direct in the identification of myocardial scar than standard ECG, clinical evaluation, or biplane left ventriculography.