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Biomedical subjects

S Edwards

Publications and source records attributed to S Edwards.

At least 163 records · Page 9Linked to original sources
PubMed1991

Mycobacterium bovis infection in humans exposed to elk in Alberta.

The evidence of zoonotic transmission of M. bovis infection in the 1 veterinarian is confirmed by growth of the organism from his sputum 6 months after animal contact. The high rate of initial tuberculin reactivity and the skin test conversions of 6 persons in contact with culture-positive animals strongly suggest that further human infection has taken place. However, the lack of baseline testing on 48/81 test-positive individuals and the relatively high proportion of immigrants in some occupational groups makes it impossible to determine the extent of reactivity and infection that can be attributed to handling diseased elk. The method of spread is likely by aerosolization of infected particles produced from the cough of live animals, or by the housing of infected material in the rendering plant or postmortem laboratory. Although isoniazid prophylaxis has not been demonstrated to be protective against M. bovis reactivation disease, it seems reasonable to offer the drug to those contacts who are newly infected. Follow-up of human contacts of animal tuberculosis must be carried out.

Adult↗
PubMed1991

Transmission of bovine virus diarrhoea virus by blood feeding flies.

Three species of blood-feeding flies (Stomoxys calcitrans, Haematopota pluvialis and Hydrotaea irritans) were fed for five minutes on a bullock persistently infected with bovine virus diarrhoea virus (BVDV) containing 10(4.5)TCID50 non-cytopathic BVDV/ml serum, then subsequently fed on BVDV-free seronegative animals maintained in isolation. Virus was isolated from recipient animals between days 5 and 10 using H pluvialis, and up to 72 hours after transmission with S calcitrans; virus isolation was negative using H irritans. Positive seroconversion results obtained with H pluvialis gave a steadily increasing antibody titre. BVDV was recovered from flies 96 hours (four days) after an infective feed for H pluvialis and S calcitrans, but for two hours only for H irritans.

Animals↗
PubMed1991

Clinical and virological observations of a mucosal disease outbreak with persistently-infected seropositive survivors.

A group of 14 four to nine month old calves, clinically healthy but persistently infected with bovine virus diarrhoea virus (BVDV), was obtained from a single farm, and reared as a group. Ten of them were male and were castrated soon after arrival. Signs of mucosal disease (MD) developed within a month and eight of the males had died or been killed on humane grounds by 2 months after purchase. The other two males and one of the females developed more chronic but progressive signs of MD and were killed during the next four months. The remaining three females showed only transient signs of MD followed by clinical recovery. They subsequently remained healthy up to slaughter at 2, 2.5 and 5 years respectively. These three survivors were persistently infected with BVDV, and shed virus in their mucous secretions, although two of them were also seropositive to the virus with fluctuating neutralizing antibody titres (at times as high as 1/960) to a range of BVDV strains including their own persisting virus.

Animals↗
PubMed1991

The effect of inducing agents on the numbers of interphase fibrillar centers in the U937 promonocytic cell line.

The mean numbers of interphase fibrillar centers have been determined in triplicate experiments, using the argyrophil (AgNOR) method. Promonocytic U937 cells were incubated with each of three inducing agents, namely, interleukin-6, granulocyte-macrophage colony-stimulating factor, and the phorbol ester 12-O-tetradecanoylphorbol-13-acetate. The cells were examined at 24, 48, and 72 h during the induction periods and their doubling time and mean AgNOR score were calculated. After 72 h, the cells were maintained in culture for a further 24 h in the absence of an inducing agent and these parameters were determined again. It was found that whereas the unstimulated U937 cells had a mean value in the region of 50 AgNORs per nucleus, this diminished to about 20 after a 72 h incubation, but rose to 30 or more when the inducing agents had been withdrawn for 24 h. These observation confirm the results of previous studies using melanoma and HL60 cell lines: however, it has now been demonstrated that a variety of agents can modulate the numbers of fibrillar centers in a very similar way in a single cell line. Furthermore, we have shown that the "undifferentiated" U937 cell AgNOR score recovers when the agents no longer act upon the cells; this implies that fibrillar center numbers are intimately related to differentiation state in cell lines, as in the case in, for example, tumor specimens.

Cell Count↗
PubMed1991

Peripherally administered 5-hydroxytryptamine elicits the full behavioural sequence of satiety.

If 5-HT acts as a peripheral satiety signal, then it should not only produce anorectic effects when administered systemically but should allow the normal behavioural sequence of satiety to develop. Food-deprived rats treated with 5 mg/kg 5-HT were found to show, when given access to food, the full normal behavioural sequence of satiety, although the sequence occurred earlier than in rats treated with saline. It is therefore argued that 5-HT must be considered as a likely candidate for a peripheral satiety signal.

Animals↗
PubMed1991

The development of an international reference panel of monoclonal antibodies for the differentiation of hog cholera virus from other pestiviruses.

A panel of 30 monoclonal antibodies was defined and characterized with respect to the binding capacity in immunoperoxidase assay to different strains of pestivirus. Using the panel it was possible to identify specifically all strains and isolates of hog cholera virus, hog cholera vaccines derived from 'C' strains, and most strains of bovine viral diarrhoea/border disease (BVD/BD) viruses (including those isolated from pigs). A small proportion of BVD/BD isolates from pigs and ruminants reacted only with the monoclonals specific for pestivirus group antigen. It is recommended that monoclonal typing methods be introduced into official procedures for the diagnosis of hog cholera/classical swine fever.

Animals↗
PubMed1991

Chronic bullous disease of childhood with oral mucosal scarring.

Chronic bullous disease of childhood (CBDC) is an acquired subepidermal bullous disease; oral involvement occurs with mouth ulcers and blisters in 57% of patients. The condition usually remits before puberty but persistence of the disease in adulthood is recognized. We report a case with severe oral scarring similar to that described in patients with adult linear IgA disease. To our knowledge this has not been previously described.

Child↗
PubMed1991

Demonstration of insulin transformation products in insulin vials by high-performance liquid chromatography.

OBJECTIVE: To assess the importance of temperature, light, agitation, and regular withdrawal of insulin on the rates of appearance of three groups of insulin transformation products (ITPs) in vials of human and beef soluble insulin. RESEARCH DESIGN AND METHODS: Twelve insulin-treated patients (6 receiving human soluble insulin, 6 receiving beef soluble insulin) participated in the study. Reverse-phase high-performance liquid chromatography was used to measure ITP in serial samples from vials stored in various laboratory environments or issued to patients. Vials in the laboratory were analyzed on nine occasions over 26 wk; those issued to patients were analyzed weekly. RESULTS: Results were expressed as rates of change (% total protein/wk). Except for human insulin stored at 4 degrees C, sampling did not accelerate transformation. Storage at higher temperatures caused more rapid transformation to all ITP groups, and human insulin was more susceptible than beef insulin. Exposure to light accelerated transformation mainly to group 3 ITP. Fibrillation occurred in beef but not human insulin carried in a shirt pocket. Results from patients' vials were consistent with reported storage conditions. CONCLUSIONS: All three ITP groups form in human and beef soluble insulin. Their rate of production is a function of temperature and light exposure. Differences between the two insulins were probably due to differences in formulation. Patients should be discouraged from hoarding vials and storing insulin in direct sunlight. One or more ITPs could contribute to the residual immunogenicity of modern insulin preparations.

Analysis of Variance↗
PubMed1991

The effect of class II gene transfection on the tumourigenicity of the H-2K-negative mouse leukaemia cell line K36.16.

There is much evidence to suggest that potentially immunogenic tumour cells can escape cytolytic immune destruction by loss of class I antigen expression. Many tumours are allele-specific class I negative and, in murine systems, reconstitution of class I expression by gene transfection leads to an increase in tumour immunogenicity. In many systems where mice have rejected class I transfected tumour cells they are also immune to a subsequent challenge with the untransfected parent tumour. In this study we have examined the effect of stable class II antigen expression (induced by gene transfection) on a class I loss mutant (H-2Kk negative) murine cell line, K36.16. We show that H-2Ek expression is more effective at increasing tumour immunogenicity than the reconstitution of H-2Kk expression in these cells. This suggests that the induction of class II antigen expression on tumour cells may provide an effective way of enhancing tumour-specific immune responses in vivo.

Animals↗
PubMed1991

Immunomagnetic purging of breast cancer from bone marrow for autologous transplantation.

Intensive chemotherapy with autologous bone marrow transplantation is a promising approach for the treatment of breast cancer, provided that clonogenic tumor cells do not contaminate the patient's bone marrow. We have previously demonstrated that a combination of 4-hydroperoxycyclophosphamide (4-HC) and immunomagnetic purging (IMP) with monoclonal antibodies and microspheres could remove 4-5 logs of clonogenic breast cancer cells from a 10-fold excess of human bone marrow cells. In the present report we have evaluated an apparatus for separating tumor cells from a large volume of human marrow. This apparatus will permit preparation of large volumes of purged marrow for use in studies of intensive therapy with autologous marrow support. Bone marrow progenitor cell (CFU-GM) recovery following this IMP technique was 85% of the unpurged control, and suggests that marrow recovery following high dose systemic chemotherapy will not be adversely affected. A phase I study to evaluate marrow reconstitution following IMP is underway. Preliminary data suggest that this IMP method will not delay engraftment in breast cancer patients receiving high-dose chemotherapy and autologous bone marrow support, but further study is required.

Adenocarcinoma↗
PubMed1990

A study of the predominant genotypes of bovid herpesvirus 1 found in the U.K.

The genotypic classification of 84 U.K. isolates of bovid herpesvirus 1 was determined by the restriction endonuclease technique. Preliminary studies with six enzymes (EcoRI, HindIII, HpaI, BamHI, PstI and BstEII) showed that the principal genotypic variants, including the live vaccine strains used in the U.K., could be identified from the digestion patterns with just two endonucleases: HindIII and HpaI. Isolates from the 1960s were all categorised as genotype 2b. From 1977 onwards, genotype 1 has predominated in mainland Britain, with occasional type 2b isolates. Type 2b viruses were isolated from both respiratory and genital disease cases. There was no evidence of genotypes 2a or 3 in the U.K.

Animals↗
PubMed1990

Round table on infectious bovine rhinotracheitis/infectious pustular vulvovaginitis virus infection diagnosis and control.

The current situation of infectious bovine rhinotracheitis/infectious pustular vulvovaginitis infection in various European countries is reviewed. Whilst some have a high serological prevalence and use live virus vaccines to control the disease, others have a low prevalence and two countries (Denmark and Switzerland) have national eradication schemes which are almost complete. Serology remains important for diagnosis although other tests such as delayed cutaneous hypersensitivity may have a role to play. New tests such as polymerase chain reaction may find increasing application where high sensitivity is required, such as the detection of virus in semen.

Animals↗
PubMed1990

Age-related differences in cardiovascular reactions to mental stress tests in women.

Tested 84 healthy, sedentary women in the laboratory during performance of difficult and easy problem-solving tasks. They were divided into three age groups: 19 to 32 years, 33 to 43 years, and 44 to 60 years (n = 28 women per group). Baseline systolic blood pressure (SBP) and diastolic blood pressure increased with age, whereas skin conductance level was lower in older women. In addition, initial SBP reactions to tasks were positively related to age, even after controlling for baseline blood pressure, aerobic fitness, and Framingham Type A Scale behavior scores. There were no differences in heart rate (HR) or "additional" HR reactions, so the anticipated decline in cardiac sympathetic response with age was not observed. The mechanisms underlying age-related reactions to mental stress are discussed.

Adult↗
PubMed1990

The relationship of DNA double-strand break induction to radiosensitivity in human tumour cell lines.

Recent data suggest that the differences in radiosensitivity between cell lines can be related to differences in dsb induction (Radford 1986a). In the light of this we have set out to assess the extent to which differences in radiation survival between human tumour cell lines can be attributed to differences in dsb induction. For nine human tumour lines survival was assayed by clonogenic assay and compared with dsb induction by irradiation at ice-bath temperature as measured by neutral filter elution. The lines varied widely in their sensitivity, ranging from a sensitive neuroblastoma (surviving fraction at 2 Gy, SF2 = 0.13) to a resistant bladder carcinoma (SF2 = 0.62). Dsb induction was found to vary between the cell lines, such that resistant cells generally suffered less damage than sensitive ones. However, the relationship between damage induction and cellular sensitivity was not a simple one, and other factors which may influence sensitivity need to be invoked. These data suggest that, in human tumour cell lines, differences in radiosensitivity may at least in part be due to different levels of damage induction, but that some lines may vary in their tolerance of damage due to differences in biological characteristics such as repair capacity.

Cell Line↗