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Biomedical subjects

S Neville

Publications and source records attributed to S Neville.

35 records · Page 2Linked to original sources
PubMed1992

Micronucleus induction in bone-marrow cells following consumption of cooked beef in mice. Preliminary investigations.

The bone-marrow micronucleus assay was used to investigate whether the consumption of cooked meat could induce chromosome damage. There was no difference in the micronucleus frequency of mice on normal diet (cereal-based, non-purified diet) and mice on normal diet supplemented with microwaved meat. However, supplementing the normal diet with well-done pan-fried meat or rare charcoal-barbecued meat or well-done charcoal-barbecued meat produced significant increments in the micronucleus frequency of polychromatic erythrocytes--the increments were of the order of 73% (p = 0.045), 90% (p = 0.047) and 136% (p = 0.001) respectively and they were observed after a 21-day feeding trial. These results suggest that ingestion of well-done pan-fried or barbecued meat may increase genetic damage, however, the accompanying decreased intake of vegetable constituents may have also contributed to the observed changes.

Animals↗
PubMed1991

Purification and initial characterisation of koala immunoglobulins.

The production of koala immunoglobulins (Ig) was elicited by the immunisation of a koala (Phascolarctos cinereus) with bovine serum albumin. This Ig was then purified using the highly specific techniques of affinity chromatography. The purified protein was compared with a "potential" koala Ig protein which was subsequently purified by Protein G chromatography and both proteins were further characterised by agarose/SDS-PAGE and immunoelectrophoresis. Results indicate that koalas do produce Ig in response to antigen challenge, koala Ig has a higher net negative charge than that seen in most other mammals and possibly two subclasses of IgG and IgM are present in normal koala serum.

Animals↗
PubMed1990

The induction of P450 I proteins by aromatic amines may be related to their carcinogenic potential.

The hypothesis has been put forward that genotoxic aromatic amines which induce the P450 I family of haemoproteins, the major enzyme involved in their bioactivation, are more likely to be carcinogenic when compared to those chemicals that fail to do so. Induction of the hepatic P450 I family of proteins by carcinogenic aromatic amines and their non-carcinogenic isomers and analogues was investigated in the rat and correlated to their carcinogenic potential. The activity of the P450 I A1 protein was monitored by the O-deethylation of ethoxyresorufin and of the P450 I A2 by the activation of the premutagen Glu-P-1 to mutagenic intermediates in the Ames test. Results were always confirmed immunologically in Western blots employing antibodies to rat P450 I A1 which recognize both proteins of the P450 I family. With all groups of chemicals used in the present study, the members displaying carcinogenicity were always the more potent inducers, while the non-carcinogenic isomers or analogues displayed little or no induction. It appears that a relationship exists between the carcinogenicity of aromatic amines and their ability to induce hepatic P450 I activity.

Amines↗
PubMed1990

Flavimonas oryzihabitans infection of a surgical wound.

An unusual case of a post operative wound infection involving Flavimonas oryzihabitans is described. This organism is rarely isolated from human sources. It can cause infections in patients having continuous ambulatory peritoneal dialysis. Our patient developed a wound infection 2 months after femoro-popliteal bypass grafting. The source of the organism was unknown.

Humans↗
PubMed1990

Use of traction in cervical spine fractures during interhospital transfer by aircraft.

Despite significant improvement in the organization and function of the nation's emergency medical services and the increasing sophistication of initial providers of critical care, there has apparently been no reduction in the incidence of neurological deficits suffered by patients with unstable cervical spine injuries during management prior to intervention by the spine surgeon. In analyzing the techniques used to stabilize patients with suspected unstable cervical spine injuries during this phase, we conclude that present standard techniques are either insufficient or potentially destabilizing. We have developed a system that will permit the use of cervical traction, applied with a halter or the standard Gardner-Wells tongs, during the prehospital phase of management of patients with cervical spine injuries. Based on our experience with the system, we recommend that patients with such injuries be stabilized with skeletal traction when transferred between hospitals by air ambulance. Logic permits consideration of the concept even earlier in the prehospital phase of management and in ground ambulances.

Adult↗
PubMed1989

A rationale for the non-mutagenicity of 2- and 3-aminobiphenyls.

Of the three isomeric forms of aminobiphenyl, only 4-aminobiphenyl is an established carcinogen while the 2-isomer is considered as a non-carcinogen and 3-aminobiphenyl is at best described as a weak carcinogen. In the present studies we investigated the mutagenicity of these three compounds, their N-hydroxy derivatives and their nitrosoderivatives in the Ames test using the Salmonella typhimurium strains TA98 and TA100. The studies were performed both in the absence and presence of an activation system derived from the liver of rats pretreated with Aroclor 1254. Of the three isomers only 4-aminobiphenyl exhibited mutagenicity and only in the presence of an activation system. N-Hydroxy-4-aminobiphenyl was a potent direct mutagen in both bacterial strains, N-hydroxy-2-aminobiphenyl was mutagenic in only TA100 while N-hydroxy-3-aminobiphenyl displayed mutagenicity in neither strain. Both 2- and 3-nitrosobiphenyls were direct mutagens in strain TA100. These findings suggest that the weak carcinogenicity of 3-aminobiphenyl may be attributed to the lack of genotoxicity of its N-hydroxyderivative, whereas in the case of 2-aminobiphenyl it may be due to the inability of the hepatic preparations to catalyse its N-hydroxylation, which is in agreement with published in vivo metabolic studies. It is interesting that of the three isomers only 2-aminobiphenyl is non-planar, forming a dihedral angle of 40 degrees, and this may preclude it from acting as a substrate of the P-450I family of haemoproteins, which selectively catalyses the N-hydroxylation of many aromatic amines including 4-aminobiphenyl.

Aminobiphenyl Compounds↗
PubMed1989

A study of the mutagenicity of melatonin and 6-hydroxymelatonin.

The mutagenicity of melatonin and its major metabolite 6-hydroxymelatonin were evaluated using the Ames test and three strains of Salmonella typhimurium--TA 97, TA 98, and TA 100. Neither compound exhibited mutagenicity whether in the presence or absence of an activation system derived from rats induced with Aroclor 1254. Positive controls were employed throughout and gave the expected response. We conclude that melatonin, 6-hydroxymelatonin, and their microsomal metabolites are not mutagenic in the Ames test.

Animals↗
PubMed1989

Complement activation within the coeliac small intestine is localised to Brunner's glands.

Complement activation may play an important role in the pathogenesis of coeliac disease. In the present study immunohistochemical localisation of C3 and of a neoantigen exposed only on the terminal C5b-9 complement complex has been performed on small intestinal biopsy sections from newly diagnosed untreated coeliac patients, from coeliac patients on long-term gluten-free diet and from disease controls. Levels of C3 were markedly increased in treated coeliac patients compared with controls. Staining of C3 was concentrated subepithelially and within the centre of the lamina propria. No staining was detected at these sites using antibody to the neoantigen, however, strongly suggesting that the increased levels of C3 seen in the coeliac patients was the result of increased extravasation of serum proteins rather than complement activation. Surprisingly, complement activation was detected within the glands of Brunner. Positive staining using anti-C5b-9 neoantigen was found in all coeliac patients, both treated and untreated. Three of the 13 disease controls also showed reactivity with this antibody. This novel finding suggests that Brunner's glands, hitherto largely neglected structures, may play an important role in the development of coeliac disease.

Antigens↗
PubMed1989

[Inter-individual testing of water-soluble oral contrast media with reference to their diagnostic value, side effects and taste].

Three groups of patients (n = 55, 53 and 54) were examined with the x-ray contrast media Gastrografin, Peritrast-Oral GI, and Telebrix Gastro and Telebrix Gastroo assess the diagnostic ranking, side effects and taste of water-soluble oral contrast media. No significant differences were seen in respect of diagnostic ranking and side effects. Side effects were exclusively abdominal symptoms; there was no difference with regard to laxative action. Telebrix Gastroas accepted significantly better in respect of taste than Gastrografin and Peritrast-Oral GI.

Administration, Oral↗
PubMed1988

Jacalin: its binding reactivity with immunoglobulin A from various mammalian species.

Jacalin, a recently described lectin, has been demonstrated to have unique binding properties for some forms of human immunoglobulin A (IgA). The lectin has now become commercially available, immobilized to a beaded agarose support. This laboratory undertook a short study to determine whether this immobilized jacalin demonstrated any binding capacity for IgA from various mammalian species, with a view to utilizing this new form of affinity chromatography to simplify the purification of IgA from these species. Utilizing the chromatographic conditions recommended by the manufacturer, the bound jacalin demonstrated no IgA reactivity from pig, goat, horse, cow or dog.

Animals↗
PubMed1987

Spinal instability and the log-rolling maneuver.

Immobilization of the spine is of prime concern during transportation of trauma patients to prevent neurologic compromise. In an attempt to study certain techniques of prehospital thoracolumbar spine immobilization, we radiographically evaluated the motion of the thoracolumbar spine in a volunteer with a stable spine, a cadaver with an unstable thoracolumbar spine, and a patient with a T12-L1 fracture dislocation. Both the backboard and the Scoop stretcher offered adequate stabilization for thoracolumbar spine instability. The logroll maneuver presented the greatest possibility for movement of the spine at the unstable thoracolumbar segment.

Adult↗
PubMedDate not supplied

Sex is an important variable affecting spontaneous micronucleus frequency in cytokinesis-blocked lymphocytes.

The micronucleus frequency in cytokinesis-blocked lymphocytes of 152 females and 113 males aged between 20 and 89 years (minimum of 15 subjects per sex per decade) was compared. Marked differences in the micronucleus frequency of males and females were observed: (a) there was a greater dispersion in the results for females when compared to males in all age groups older than 40 years; (b) there was a significant positive correlation between micronucleus frequency and age in both sexes (p < 0.0001) but the slope of the linear regression line was steeper in females (slope = 0.499 micronuclei/year) compared to males (slope = 0.289 micronuclei/year) (p < 0.0045); (c) the micronucleus frequency in females (Mf) was significantly higher than the micronucleus frequency in males (Mm) in all decades examined (p < 0.05), the Mf,Mm ratio varied between 1.47 and 1.65 (mean +/- 1 SEM = 1.53 +/- 0.03) and showed no trend with age. These results suggest that an added mechanism, possibly the loss of X chromosomes, is contributing to the micronucleus frequency in females and highlights the importance of sex as a variable that has to be taken into consideration when interpreting data from cross-sectional studies utilising the cytokinesis-block micronucleus assay as a biomarker of chromosome damage.

Adult↗
PubMedDate not supplied

Induction of the P-450 I family of proteins by polycyclic aromatic hydrocarbons: possible relationship to their carcinogenicity.

The hypothesis has been put forward that mutagenic polycyclic aromatic hydrocarbons which induce the P-450 I family of cytochromes, the major enzyme system responsible for their activation, are likely to be carcinogenic. In order to test this hypothesis, rats have been pretreated with a number of polycyclic aromatic hydrocarbons of different mutagenic and carcinogenic potency and hepatic P-450 I activity was monitored using chemical probes such as the O-deethylation of ethoxyresorufin and metabolic activation of Glu-P-1 to mutagens, and immunologically employing polyclonal antibodies against purified rat P-450 I A1. All compounds studied enhanced P-450 I activity and induced P-450 I apoproteins but the extent of induction was very markedly different. The results are discussed with reference to the mutagenicity of these chemicals in the Ames test and their carcinogenicity in the classical mouse skin model. A relationship appears to exist between carcinogenicity of polycyclic aromatic hydrocarbons and their ability to induce hepatic P-450 I activity.

Animals↗
PubMedDate not supplied

Planning home care services for people living with AIDS.

As the number of individuals infected with the human immunodeficiency virus (HIV) increases, so does the demand for healthcare services. The debilitating manifestations seen in the later stages of illness, in association with the diagnosis of acquired immune deficiency syndrome (AIDS), often require the assistance of home care providers. Establishing a database of information, not only on the clinical needs of individuals but also on person-specific details, is essential to identify the nursing care needs of this population. The delivery of home care services to people living with AIDS (PLWA) includes the client, the significant other(s), and the community in which the client resides.

Acquired Immunodeficiency Syndrome↗