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Biomedical subjects

J Chisholm

Publications and source records attributed to J Chisholm.

At least 19 recordsLinked to original sources
PubMed2006

Effect of heat and pressure processing on DNA fragmentation and implications for the detection of meat using a real-time polymerase chain reaction.

The design of real-time polymerase chain reaction (PCR) assays for the detection of meat in processed products has focused on using small amplicons, often to the detriment of specificity. However, the relationship between amplification rates and the amplicon size for processed meat products has yet to be determined. To investigate this relationship, real-time PCR assays were designed to give a series of amplicons of increasing size. These assays were then used to assess amplification rates, in relation to amplicon size, in processed meat matrices. Although the most sensitive assays were those that used the smallest amplicons, amplification was still observed using amplicons of 351 base pairs for highly processed samples. It was found, therefore, that although in general, amplicons should be as small as possible, larger amplicons give efficient amplification and that small amplicons should not be chosen if they compromise assay specificity.

DNA Fragmentation↗
PubMed2005

Influenza immunisation in children with solid tumours.

We assessed response to immunisation with trivalent split virus influenza vaccine in children with non-leukaemic malignant disease. Children with solid tumours and lymphoma received one or two doses of influenza vaccine, according to current UK guidelines, in autumn 2001 and/or 2002. Children were currently receiving chemotherapy or were within 6 months of completing chemotherapy. Pre and post vaccination sera were assessed for antibodies to the prevalent influenza strains by haemagglutination inhibition (HI). Sixty six children were assessed prior to 69 episodes of vaccination. In 30% episodes, children were susceptible to all three circulating influenza viruses (65% to H1N1, 42% to H3N2 and 90% to B) and only one patient showed protective titres (HI32) against all three strains. Seroresponse rates (4-fold rise in HI) for H1N1, H3N2 and B were 52%, 33% and 51% in 65 episodes. Following immunisation protective titres to all three viruses were seen in 25 episodes (38%) and protective responses to one or two viruses were seen in a further 12 (19%) episodes. There was no significant difference in response rates among children on treatment and off treatment and by intensity of chemotherapy. Children with solid tumours and lymphoma are highly susceptible to influenza infection. Influenza vaccine was well tolerated in this patient group and children showed a significant response to immunisation. These findings support the recommendation for annual influenza vaccination in these children.

Adolescent↗
PubMed2004

Truncation of oligonucleotide primers confers specificity on real-time polymerase chain reaction assays for food authentication.

The advent of real-time polymerase chain reaction has revolutionized the field of molecular biology, but the design and optimization of these assays has been largely overlooked in the literature. This dearth of information is probably in response to the provision of assay design software and robust guidelines issued by the leading manufacturer. However, many applications require highly specific assays with no cross-amplification of non-target DNA and it has been found that the software and guidelines, whilst producing assays of great sensitivity, do not necessarily produce specific assays. Two complementary strategies were used to confer specificity on a real-time assay, first by placing the 3' end of the primers on a point of sequence heterogeneity and, second, by truncating the primers at the 5' end to lower the calculated melting temperature. Using these strategies in concert, a specific assay for a conserved region of the mitochondrial cytochrome b gene was developed that can be used for the unambiguous detection of the target species in a meat mixture. This approach can be used for any real-time polymerase chain reaction assay to increase assay selectivity and specificity.

Animals↗
PubMed2002

A randomised study of prophylactic G-CSF following MRC UKALL XI intensification regimen in childhood ALL and T-NHL.

BACKGROUND: Despite the current widespread use of prophylactic G-CSF in children with solid tumours and leukaemia, its effectiveness has not been clearly demonstrated. This randomised study evaluates the role of G-CSF given after a 5-day intensification block in children with acute lymphoblastic leukaemia (ALL). PROCEDURE: Forty-six children with ALL or T-Cell non-Hodgkins lymphoma (NHL) treated on MRC ALL 97, UKALL XI or UKCCSG 9504 NHL protocols were randomised to receive granulocyte colony-stimulating factor following either the first or the second block of intensive chemotherapy in a cross-over study to determine if the prophylactic administration of G-CSF could reduce the rate of readmission to hospital for management of febrile neutropenia. RESULTS: There was a statistically significant difference in the rate of hospital admission in the group receiving prophylaxis, with 34 of 46 being admitted, compared to 42 of 46 patients in the control arm (74 vs. 91%; P=0.0386). There were no differences found in duration of hospital admission, haematological toxicity, neutrophil recovery or duration of supportive care between the two groups. There was no demonstrable cost benefit derived from the prophylactic administration of G-CSF. CONCLUSIONS: This study shows that the prophylactic administration of G-CSF following intensification chemotherapy for childhood ALL and T-NHL produces a significant reduction in the rate of readmission to hospital for the management of febrile neutropenia.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2001

Expression and partial purification of recombinant tomato ringspot nepovirus 3C-like proteinase: comparison of the activity of the mature proteinase and the VPg-proteinase precursor.

The 3C-like proteinase (Pro) from Tomato ringspot virus (genus Nepovirus) is responsible for the processing of the RNA1-encoded (P1) and RNA2-encoded (P2) polyproteins. Cleavage between the VPg and Pro domains is inefficient in vitro and in E. coli, resulting in the accumulation of the VPg-Pro. In this study, we have compared the trans-activity of the Pro and VPg-Pro on various P1- and P2-derived precursors. Recombinant Pro and VPg-Pro were partially purified using an E. coli expression system. A mutation of the VPg-Pro cleavage site was introduced into the VPg-Pro to prevent slow release of the Pro. The Pro was five to ten times more active than the VPg-Pro on two P2 cleavage sites (at the N- and C-termini of the movement protein domain) and was approximately two times more active than the VPg-Pro on the third P2 cleavage site (between the X3 and X4 domains). Neither the Pro nor the VPg-Pro could cleave in trans P1-derived substrates containing the three cleavage sites delineating the X1, X2, putative NTP-binding protein and VPg domains. These results are discussed in light of the possible regulation of the proteinase activity during virus replication.

3C Viral Proteases↗
PubMed2001

Food allergy--towards predictive testing for novel foods.

The risks associated with IgE-mediated food allergy highlight the need for methods to screen for potential food allergens. Clinical and immunological tests are available for the diagnosis of food allergy to known food allergens, but this does not extend to the evaluation, or prediction of allergenicity in novel foods. This category, includes foods produced using novel processes genetically modified (GM) foods, and foods that might be used as alternatives to traditional foods. Through the collation and analysis of the protein sequences of known allergens and their epitopes, it is possible to identify related groups which correlate with observed clinical cross-reactivities. 3-D modelling extends the use of sequence data and can be used to display eptiopes on the surface of a molecule. Experimental models support sequence analysis and 3-D modelling. Observed cross-reactivities can be examined by Western blots prepared from native 2-D gels of a whole food preparation (e.g. hazelnut, peanut), and common proteins identified. IgEs to novel proteins can be raised in Brown Norway rat (a high IgE responder strain) and the proteins tested in simulated digest to determine epitope stability. Using the CSL serum bank, epitope binding can be examined through the ability of an allergen to cross-link the high affinity IgE receptor and thereby release mediators using in vitro cell-based models. This range of methods, in combination with data mining, provides a variety of screening options for testing the potential of a novel food to be allergenic, which does not involve prior exposure to the consumer.

Allergens↗
PubMed2001

Unintentional traumatic brain injury in children: the lived experience.

Brain injury is a major cause of injury death and long-term neurological impairment in children often requiring long-term support. Despite the significance and frequency of such injuries, very little is known about the circumstances of these injuries, the long-term outcomes and family support needs. In this pilot study of 10 families of children with traumatic brain injury, participants described a variety of factors which contributed to their child's injury (inattentiveness, unfamiliarity, developmental level, lack of protective gear, invulnerability, peer pressure, environmental hazards and lack of supervision). As a result of their child's injury, family members described fundamental shifts in how they view life and that the roles and responsibilities of family members changed drastically. Study families experienced sustained uncertainty and described the impact on family relationships. While social support was clearly a mediating factor, families described the need for ongoing support and services to help them adapt to new roles, cope with new challenges, and manage sequellae such as post-traumatic headaches, epilepsy, learning difficulties and behavioural problems. The study findings represent an initial attempt to develop knowledge upon which focussed injury prevention interventions can be developed. Furthermore, this information will assist in the determination of appropriate health, rehabilitative, and educational support services for children with brain injuries. Involving families in this way will enhance the implementation of practical and useful support services for families of children with brain injuries.

Accident Prevention↗
PubMed2000

A comparison of the awareness and utilisation of postoperative health services provided to women with breast cancer in public and private hospitals.

Nurses at a metropolitan Cancer Care Centre (CCC) noted that women who have had recent breast surgery for carcinoma had significantly different levels of knowledge and use of support services depending upon public or private hospitalisation. The public hospital participants were more aware of the range of available services (mean = 3.6) compared to women from the private sector (mean = 2.6). In addition, the public hospital participants were more likely to access a wider range of services post discharge (mean = 2.21) compared to the private hospital women (mean = 0.85). A significant difference was found between younger and older women's use of services.

Adult↗
PubMed2000

The context, content and consequences of mothering a child with disabilities.

Due to recent advances in biomedical science and technology, infants and children with complex medical needs and disabling conditions are surviving and being cared for at home more than ever before. Sociocultural influences and economic policies place mothers in the home as primary caregivers of children. Their caregiving work is largely invisible. The information provided in this paper is intended to make the work of mothering a child with disabilities more visible while alerting nurses to the impact of this trend on mothers. Strategies to minimize the negative consequences are included.

Caregivers↗
PubMed1999

Proteolytic processing of tomato ringspot nepovirus 3C-like protease precursors: definition of the domains for the VPg, protease and putative RNA-dependent RNA polymerase.

Tomato ringspot nepovirus (TomRSV) RNA-1 encodes a putative NTP-binding protein (NTB), a putative viral genome-linked protein (VPg), a putative RNA-dependent RNA polymerase (Pol) and a serine-like protease (Pro), which have been suggested to be involved in viral RNA replication. Proteolytic processing of protease precursors containing these proteins was studied in Escherichia coli and in vitro. The TomRSV protease could cleave the precursor proteins and release the predicted mature proteins or intermediate precursors. Although processing was detected at all three predicted cleavage sites (NTB-VPg, VPg-Pro and Pro-Pol), processing at the VPg-Pro cleavage site was inefficient, resulting in accumulation of the VPg-Pro intermediate precursor in E. coli and in vitro. In addition, the presence of the VPg sequence in the precursor resulted in increased cleavage at the Pro-Pol cleavage site in E. coli and in vitro. Direct N-terminal sequencing of the genomic RNA-linked VPg, of the mature protease purified from E. coli extracts and of radiolabelled mature polymerase purified from in vitro translation products revealed the sequences of the NTB-VPg, VPg-Pro and Pro-Pol dipeptide cleavage sites to be Q/S, Q/G and Q/S, respectively. In vitro processing at the NTB-VPg and Pro-Pol cleavage sites was not detected upon mutation or deletion of the conserved glutamine at the -1 position of the cleavage site. These results are discussed in light of the cleavage site specificity of the TomRSV protease.

3C Viral Proteases↗
PubMed1998

Clinical Usefulness of Flow Cytometry in Detection and Quantification of Fetomaternal Hemorrhage.

> Objective: To compare the technique of immunofluorescence flow cytometry against traditional Kleihauer testing with respect to the sensitivity and specificity of clinical detection of fetomaternal hemorrhage. Methods: Blood samples from D-negative unsensitized postpartum women were analyzed by flow cytometry (customized, directly conjugated monoclonal anti-D) and Kleihauer testing using commercial kits as well as a manual technique. Results: Both flow cytometry and manual Kleihauer tests performed well in vitro against known standards, giving similar results with detectable fetal cells in the range of 2-10%. Correlation of in vivo results obtained by flow cytometry and either Kleihauer method was poor. The percentage of fetal red cells detected by flow cytometry was approximately twice that of the manual Kleihauer. Commercial Kleihauer testing proved unreliable in the in vivo setting. Conclusions: Flow cytometry offers a reliable alternative to traditional Kleihauer testing for detecting fetomaternal hemorrhage and may, with standardized methodology, help optimize immunoprophylaxis against erythroblastosis fetalis.

Journal Article↗
PubMed1995

Seconds count: the Kenny and Jeremy stories.

In this era of health care reform and restraint, there is a resurgence of interest in health promotion and injury prevention. This renewal has added another dimension to the practice of nursing--the expectation that health teaching is included in our interactions with families. This paper will explore submersion injuries in children which, according to Brill, (1987) are uniquely preventable. The ultimate aim of discussing this topic is an increased commitment by nurses to the prevention of submersion injuries.

Child, Preschool↗
PubMed1994

Neuropharmacology of nimodipine: from single channels to behavior.

To supplement the existing pharmacological evidence describing the effects of nimodipine, a 1,4-dihydropyridine with calcium channel blocking properties, our group has used a multidisciplinary approach. This work attempts to characterize the mechanism of action of nimodipine in neurons as well as investigate the effects of nimodipine in models of neurodegeneration and dementia. Patch voltage clamp studies demonstrated high-affinity nimodipine block of voltage-dependent L-type calcium channel activity in central neurons from primary cultures of neonatal rat hippocampus. Nimodipine potently blocks depolarization-induced increases in free calcium throughout the soma of these hippocampal neurons. In addition, somatic free calcium elevations induced by acute beta A4(25-35) exposure are also potently blocked by nimodipine. In behavioral studies, nimodipine produced enhanced retention in aging rabbits on eyeblink conditioning and also was shown to protect against medial septal lesion-induced retention deficits in a spatial learning task. These findings, from channel to behavioral effects, support the therapeutic usefulness of nimodipine in the treatment of aging and dementia and are consistent with the view that calcium regulation is important in disorders of neuronal degeneration.

Aging↗