The differential response of normal and ischaemic Purkinje fibres to clofilium, d-sotalol and bretylium

To determine whether ischaemic tissue is more sensitive than normal tissue to class III anti-arrhythmic agents, we studied the effects of the class III agents clofilium, d-sotalol and bretylium on normal and ischaemic Purkinje fibres one day after ligation of canine left anterior descending coronary artery. In ischaemic Purkinje fibres superfused with normal Tyrode's solution (4mM K+, 2.7mM Ca+2) clofilium produced early afterdepolarisations at 10(-7)M and 10(-6)M, d-sotalol at 10(-5)M to 10(-3)M, and bretylium at 10(-3)M. The early afterdepolarisation response of ischaemic tissue, which in some cases prolonged action potential duration to beyond 10 s, was significantly different from the simple prolongation of action potential duration seen in normal Purkinje fibres at the same concentrations. Clofilium and d-sotalol differentially produced early afterdepolarisations at or very near "anti-arrhythmic" doses. Therefore, class III anti-arrhythmics produced early afterdepolarisations differentially in ischaemic tissue at concentrations which did not produce early afterdepolarisations in normal tissue.     

Preliminary evaluation of the haemagglutination and haemagglutination inhibition tests for avian infectious bronchitis virus

Four of the 9 strains of infectious bronchitis virus which were concentrated and treated with phospholipase C type 1 showed haemagglutination activity. These strains, Holte, Massachusetts 41 (M41), H120 and Connecticut, were distinguishable by the haemagglutination inhibition (HI) test but showed much closer relationships than could be detected by the plaque reduction (PR) test. The four haemagglutinating strains were used to compare the HI and PR titres of 17 anti sera prepared against reference and field virus strains. In most cases titres were similar although there was a tendency for the HI titres to be higher than the PR titres especially with M41 antigen. HI titrations of the pooled sera from 20 birds infected with M41 showed a peak of activity at 14 days after infection which was not detected by serum neutralisation or complement fixation tests. HI titres of individual sera from birds infected 21 days previously with M41 virus compared favourably with serum neutralisation titres but showed little relationship to the complement fixation titres.     

Adrenocortical, beta-endorphin and behavioral responses to graded stressors in differentially reared rats

Isolation rearing has long been suspected to alter hormonal and behavioral responses to stress. Two experiments were conducted to test the hypothesis that isolates are more timid or fearful than socially reared rats when exposed to novel test environments. In both, isolate response to 3 graded stressors was compared to that of socially-reared rats. In the first experiment, animals were handled, shocked or not treated prior to testing to produce three levels of conditioned fear. They were then tested on four paradigms previously shown sensitive to conditioned fear: open field activity, emergence latency, auditory startle, and latency to accept food from the experimenter. In the second experiment, rats were given a 0-, 5- or 20-min forced swim, then sacrificed for analysis of plasma corticosterone and pituitary and hypothalamic beta-endorphin. It was found that isolates showed little evidence of enhanced behavioral timidity, although rearing effects were seen on all 4 behavioral measures. Plasma corticosterone levels increased in a graded fashion over the course of the forced swim, but there was no effect of rearing conditions. While there were no effects of rearing or stress on hypothalamic beta-endorphin, pituitary beta-endorphin content was lower in females than in males, and isolate males had lower pituitary endorphin than social males. In summary, these experiments provide no evidence that isolation rearing produces a primary, global increase in fearfulness, but identify several behavioral and hormonal differences associated with differential housing in rats.     

Greater sensitivity of pigtailed macaques (Macaca nemestrina) than baboons to total body irradiation

Two juvenile pigtailed macaques (animals 1 and 2) received total body irradiation (TBI) followed by autologous stem cell transplantation, by a procedure known to be well tolerated by baboons. In this procedure, the TBI consisted of treatment on two consecutive days with 255cGy on one side, followed after 1-2 min by a similar dose on the other side. The two pigtailed macaques showed rapid haematopoietic engraftment, but succumbed either to systemic cytomegalovirus (CMV) infection and necrotising colitis or to haemorrhagic cystitis and tubulointerstitial nephritis. For four further pigtailed macaques (animals 3-6) the radiation procedure was changed to four equal doses of 255cGy, given 6-12 h apart. Animals 4-6 all showed engraftment and survived for long periods (>218 days), with no, or only minor treatable, complications. Animal 3 failed to show engraftment and succumbed to radiation-induced vascular lesions and severe multiorgan haemorrhages. The results suggest that pigtailed macaques have a lower tolerance threshold than baboons, rhesus macaques or human beings to TBI, the adverse effects of TBI being indistinguishable from those seen in human patients. The results also suggest that a hyperfractionated radiation procedure can prevent radiation-induced morbidity and mortality in pigtailed macaques.     

Viruses and virus-like particles detected in samples from diseased game birds in Great Britain during 1988

During 1988, 108 samples were received from game birds (78 from pheasants, 28 from partridges and two from quail) for virus isolation or detection; 89 being received during the June to August rearing period. The most common clinical signs resulting in the submissions were death, scour and stunting. Virus or virus-like particles were detected in 51 cases, 43 as a result of direct electron microscopy of gut contents, seven by agar gel precipitin test for the presence of Marble spleen disease antigen and one by isolation, of a rotavirus. Particles observed by electron microscopy were: rotavirus - 15, adenovirus - 1, reovirus - 1, enterovirus - 1, 'fimbriated' virus-like particles - 10, rod-shaped virus-like particles - 19, On three occasions more than one type of particle was seen in the same sample.     

Detection of West Nile virus in the tissues of specific pathogen free chickens and serological response to laboratory infection: a comparative study.

Using an isolate of West Nile virus (WNV) from lineage 1 (Goose/Israel 1998), groups of specific pathogen free chickens were experimentally infected via the subcutaneous or intravenous routes. To evaluate the relative efficiency of detecting the virus in the infected chickens, samples from a range of tissues and organs were examined by virus isolation tests in tissue culture, including Vero, primary chicken embryo liver and fibroblast cells, and polymerase chain reaction (PCR) analyses. Additionally, in order to investigate the serological response of the chickens and produce WNV monospecific antibodies, serum samples were collected from the birds during the trial and analysed for antibodies by virus neutralization (VN) and the plaque-reduction neutralization test (PRNT). No clinical signs or gross pathological changes were seen in any of the inoculated chickens throughout the study. The nested PCR used in the study appeared to be significantly more sensitive at detecting the presence of the virus in both the tissues and the inoculated Vero cell cultures compared with the detection of gross cytopathic changes as observed in infected Vero cell culture. No cytopathic changes were seen in the inoculated avian cell cultures. Following primary inoculation of the chickens there was a weak antibody response 15 days post-inoculation. However, following re-inoculation with inactivated WNV and adjuvant there was a substantial increase in the neutralizing antibody titres when tested 2 weeks later. The results obtained suggested that the PRNT was more sensitive than the conventional VN test. Based on detection of virus and serology there was no evidence of viral transmission to the close contact controls. It can be concluded that the PCR used in this study was more sensitive than virus isolation for the detection of WNV while the PRNT also appeared more sensitive than the conventional VN test.     

Assessing the roles of demographic,social, economic,environmental, health-related,and political factors on risk of osteoporosis diagnosis among older adults

Summary

Until now, there have been only a few retrospective studies that focused on the outcomes of sandwich vertebral bodies (SVBs). This is a long-term retrospective cohort study to investigate the SVBs. We found that although patients with SVBs had a relatively high risk of developing new fractures after VA, the incidence rate of new fractures was not significantly different from that of the control group. However, the statistical power of this study was very limited. Therefore, and because the refracture rate in these patients is substantial, routine long-term monitoring of patients after VA for osteoporosis is strongly recommended.

Background

Sandwich vertebral bodies (SVBs) are intact unaugmented vertebral bodies between two previously augmented vertebrae. Until recently, only a few studies have reported the outcomes and strategies for SVBs. This retrospective cohort study aimed to describe the clinical features and incidence of new fractures in patients with SVBs.

Methods

The clinical data were collected from 179 patients with 237 symptomatic osteoporotic vertebral compression fractures who underwent vertebral augmentation (VA). Among them, 23 patients with 24 levels of SVBs were included. Spinal radiographs (X-ray and CT) of all patients were evaluated prior to surgery 1 day after primary VA and during follow-up.

Results

All patients successfully underwent PKP with an average follow-up period of 21.48 months. Asymptomatic cement leakage occurred in four patients (17.4%), and eight patients (34.8%) developed new fractures following primary PKP, including four sandwich, six adjacent, four remote vertebral fractures, and one re-collapse of cemented vertebrae. The incidence of new fractures in the SVB and control groups was 16.7% (4/24) and 13.0% (6/46), respectively, but there was no significant difference.

Conclusions

Although patients with SVBs had a relatively high risk of developing new fractures after VA, the incidence rate of new fractures was not significantly different from that of the control group. However, the statistical power of this study was very limited. Therefore, and because the refracture rate in these patients is substantial, routine long-term monitoring of patients after VA for osteoporosis is strongly recommended.