Detection of turkey rhinotracheitis virus in turkeys using the polymerase chain reaction

Six-week-old turkey poults were infected with the virulent UK/3B/85 strain of TRTV. Tracheal and oesophageal swabs were made every 2 to 3 days from groups of five poults and the RNA extracted. The TRTV RNA was then reverse-transcribed into complementary DNA (cDNA) using an oligonucleotide complementary to the 3' end of the fusion protein (F) mRNA. The cDNA was then used in a polymerase chain reaction (PCR) with an upstream primer to generate a product of approximately 0.5 kbp which was detected by ethidium bromide staining after electrophoresis. In this way, TRTV was detected in both types of swab for 17 to 19 days post-infection, nearly 2 weeks after the peak titres of infectious virus. Swabs which were allowed to dry completely before RNA extraction were as successful as swabs kept wet and extracted almost immediately, useful for when samples are collected in the field. The oligonucleotides amplified the 0.5 kbp product from TRTV strains isolated in six countries over a 13-year period, indicating that they might be usable as 'universal' oligonucleotides for TRTV detection.     

Influence of chemical structure on the fracture behaviour of dimethacrylate composite resins

Previous studies have shown that the fracture resistance of dimethacrylate-based dental composite resins is enhanced by post-curing the matrix. Here, the influence of the chemical nature of the resin matrix is examined by a study of the fracture properties of composite resins formulated from 15 homologous dimethacrylate monomers and filled to 75 wt% with treated silica. The fracture toughness was determined via the double torsion technique and the elastic modulus and flexural strength were measured in flexure. The fracture energy calculated from the fracture toughness and elastic modulus, varied between 60 and 300 J/m2 while the fracture toughness ranged from 0.2 to 2.0 MN/m3/2 and the flexural strength varied from 17 to 111 MPa. The use of a blend of monomers was found to have a synergistic effect on the fracture resistance. Increasing the length of flexible spacer units (methylene or oxyethylene) between the methacrylate groups initially improved the fracture properties; however, beyond a certain length, these properties were impaired.     

Spontaneous cytotoxicity of murine cells treated with the interferon inducers BRL 5907 and BRL 10739.

The effects of the polyribonucleotide interferon inducers, BRL 5907 and BRL 10739, on the spontaneous cytotoxicity of CBA mouse cells towards the allogeneic lymphoma EL-4, were investigated. Intravenous administration of BRL 5907 and BRL 10739 increased the cytotoxic activity of a non-adherent, theta-negative, surface immunoglobulin-negative cell present in the spleen, but had no effect on cells in the lymph nodes. Spleen cell cytotoxicity was established within 24 h of injection of the polyribonucleotides, but had disappeared by 4 days. In addition, injection of mice with BRL 10739 increased the spontaneous cytotoxicity of a nylon-wool-adherent, theta-positive spleen cell. Intraperitoneal injection of mice with BRL 5907 and BRL 10739 also enhanced the cytotoxic activity of a non-adherent peritoneal exudate cell.     

Phosphorylated KDR is expressed in the neoplastic and stromal elements of human renal tumours and shuttles from cell membrane to nucleus

Vascular endothelial growth factor (VEGF)-A is an important angiogenic factor in establishing the vasculature in renal cell carcinomas (RCCs). Since little is known about VEGF signalling in RCCs, the profile of phosphorylated KDR (pKDR) has been investigated and the intracellular location of the receptor has been examined in the present study. Using two monoclonal antibodies raised against the phosphorylated KDR epitopes (Y1059 and Y1214) known to mediate different VEGF functions, together with a commercial anti-KDR antibody and immunohistochemistry, the expression of pKDR was investigated in a series of normal (n = 25) and neoplastic kidneys (n = 54; clear cell n = 35; papillary n = 10; oncocytomas n = 8). pKDR was present in many tissue elements of both normal and neoplastic renal tissues, with strong expression in the cell membrane, cytoplasm, and nuclei of normal kidney and tumour cells, as well as endothelial cells in tumours of all histological types. Patterns and intensity were similar using both anti-pKDR antibodies. There was no significant correlation in clear cell carcinomas between pKDR expression and age (p = 0.57), tumour size (p = 0.2), gender (p = 0.59), grade (p = 0.2) or histological type (p = 0.36). To delineate further the intracellular processing that might account for the cellular distribution, confocal microscopy was also performed. Antibodies to the different phosphorylated epitopes demonstrated different intracellular staining patterns. This study shows that pKDR is present in a wide variety of renal tumours, suggesting that anti-VEGF therapy might have direct effects on tumour cells. It further suggests that cells traffic pKDR depending on the precise KDR tyrosines that are autophosphorylated in a manner that enables receptor activation to result in different functions.     

Cardiovascular responses of women with chronic fatigue syndrome to stressful cognitive testing before and after strenuous exercise

OBJECTIVE: The purpose of this study was to compare the cardiovascular responses of patients with chronic fatigue syndrome (CFS) to healthy control subjects when performing stressful cognitive tasks before and after strenuous exercise. METHOD: Beat-by-beat blood pressure and electrocardiogram were recorded on 19 women with CFS and 20 healthy nonexercising (ie, sedentary) women while they performed cognitive tests before, immediately after, and 24 hours after incremental exercise to exhaustion. RESULTS: Diminished heart rate (p <.01) and systolic (p <.01) and diastolic (p <.01) blood pressure responses to stressful cognitive testing were seen in patients with CFS when compared with healthy, sedentary controls. This diminished stress response was seen consistently in patients with CFS across three separate cognitive testing sessions. Also, significant negative correlations between self-ratings of CFS symptom severity and cardiovascular responses were seen (r = -0.62, p <.01). CONCLUSIONS: Women with CFS have a diminished cardiovascular response to cognitive stress; however, exercise did not magnify this effect. Also, the data showed that the patients with the lowest cardiovascular reactivity had the highest ratings of CFS symptom severity, which suggests that the individual response of the patient with CFS to stress plays a role in the common complaint of symptoms worsening after stress.     

Development of an implantable artificial lung: challenges and progress

Unlike dialysis, which functions as a bridge to renal transplantation, or a ventricular assist device, which serves as a bridge to cardiac transplantation, no suitable bridge to lung transplantation exists. Our goal is to design and build an ambulatory artificial lung that can be perfused entirely by the right ventricle and completely support the metabolic O2 and CO2 requirements of an adult. Such a device could realize a substantial clinical impact as a bridge to lung transplantation, as a support device immediately post-lung transplant, and as a rescue and/or supplement to mechanical ventilation during the treatment of severe respiratory failure. Research on the artificial lung has focused on the design, mode of attachment to the pulmonary circulation, and intracorporeal versus paracorporeal placement of the device.     

Proliferative responses by immune murine popliteal lymph node cells to high-molecular-weight basic allergen of ryegrass pollen and its cyanogen bromide fragments

High-molecular-weight basic allergen (HMBA) of ryegrass pollen and its fragmented form obtained by cleavage with cyanogen bromide (CNBr) (HMBA-frag) were evaluated for their immunogenicity in terms of their capacity to stimulate the in vitro proliferative responses of the in vivo antigen-primed popliteal lymph node (PLN) cells. For this purpose, mice (C3H/HeJ) were immunized in the hind foot pads with solutions containing 1-5 micrograms of HMBA or HMBA-frag emulsified in Freund's complete adjuvant (FCA). Eleven days later, single-cell suspensions of the PLN were cultured in vitro for 4 days in the presence of either HMBA or HMBA-frag at concentrations ranging from 0.625 to 20 micrograms/ml. 3H-thymidine was added to the cultures 6 h prior to harvesting the cells. The degree of proliferation was assessed from the extent of intracellular incorporation of the 3H-thymidine by the PLN cells. Comparable degrees of lymphocyte proliferation were consistently obtained on stimulation with either HMBA or HMBA-frag of PLN cells from mice immunized with the allergen HMBA. A similar finding was made using PLN cells from mice immunized with the HMBA-frag. This study demonstrated that the CNBr-derived fragments of HMBA retained the immunogenicity of the parent molecule HMBA in terms of being able to (i) induce the in vivo priming of PLN cells and (ii) elicit the in vitro proliferative response of the antigen-primed PLN cells.