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Biomedical subjects

S Johnstone

Publications and source records attributed to S Johnstone.

At least 19 recordsLinked to original sources
PubMed2006

Expression of vascular endothelial growth factor (VEGF) in normal oral mucosa, oral dysplasia and oral squamous cell carcinoma.

Vascular endothelial growth factor (VEGF) is a potent angiogenic cytokine implicated in tumour vasculogenesis. A significant increase in vascularity occurs during the transition from normal oral mucosa (NOM), through dysplasia, to squamous cell carcinoma (SCC). This study investigated the presence of VEGF in NOM, oral dysplasia and SCC. The correlation between VEGF expression and the grade of dysplasia or differentiation of SCC was also examined. Specimens consisting of NOM, oral dysplastic lesions and oral SCC were stained using standard immunohistochemistry methods to determine VEGF expression. Statistical analysis indicated an up-regulation of VEGF during the transition from NOM, through dysplasia to SCC. There was also a significant difference in expression according to differentiation of SCC, but not grade of dysplasia. As VEGF is a potent mediator of vascular development, these results suggest that VEGF may play an important role in the maintenance of a blood supply for developing pre-cancerous and invasive oral lesions.

Adult↗
PubMed2005

General and oral health implications of cannabis use.

Cannabis, commonly known as marijuana, is the most frequently used illicit drug in Australia. Therefore, oral health care providers are likely to encounter patients who are regular users. An upward trend in cannabis use is occurring in Australia, with 40 per cent of the population aged 14 and above having used the drug. There are three main forms of cannabis: marijuana, hash and hash oil, all of which contain the main psychoactive constituent delta-9-tetrahydrocannabinol (THC). Cannabis is most commonly smoked, however it can be added to foods. THC from cannabis enters the bloodstream and exerts its effects on the body via interaction with endogenous receptors. Cannabis affects almost every system of the body, particularly the cardiovascular, respiratory and immune systems. It also has acute and chronic effects on the mental health of some users. Therefore, chronic abuse is a concern because of its negative effects on general physical and mental health. Cannabis abusers generally have poorer oral health than non-users, with an increased risk of dental caries and periodontal diseases. Cannabis smoke acts as a carcinogen and is associated with dysplastic changes and pre-malignant lesions within the oral mucosa. Users are also prone to oral infections, possibly due to the immunosuppressive effects. Dental treatment on patients intoxicated on cannabis can result in the patient experiencing acute anxiety, dysphoria and psychotic-like paranoiac thoughts. The use of local anaesthetic containing epinephrine may seriously prolong tachycardia already induced by an acute dose of cannabis. Oral health care providers should be aware of the diverse adverse effects of cannabis on general and oral health and incorporate questions about patients' patterns of use in the medical history.

Cannabis↗
PubMed2005

TNFalpha and IL10 SNPs act together to predict disease behaviour in Crohn's disease.

BACKGROUND: The cytokines tumour necrosis factor (TNF)alpha and interleukin (IL)10 have been implicated in the pathogenesis of Crohn's disease (CD), with increased concentrations reported in patients with active disease. However, limited data exist on their effects on disease phenotype in the same population. Certain single nucleotide polymorphisms (SNPs) within the promoter region of the IL10 (-1082G/A, -592C/A) and TNFalpha (-308G/A, -857C/T) genes have been associated with altered levels of circulating IL10 and TNFalpha. METHODS: We conducted an Australian based case-control study (304 CD patients; 231 healthy controls) of these four SNPs. Further investigation of two SNPs was conducted using a logistic regression analysis. RESULTS: We identified a possible association of both IL10 SNPs and TNFalpha-857 with CD. Further investigation of a relationship with disease severity showed a significant association of higher producing IL10-1082G and TNFalpha-857C alleles with stricturing behaviour, which was strongest when these alleles were combined and persisted after multivariate analysis (p = 0.007; odds ratio (OR) 2.37, 95% CI 1.26 to 4.43). In addition, the TNFalpha-857CC genotype was independently associated with familial CD (p = 0.03; OR 3.12; 95% CI 1.15 to 8.46). CONCLUSION: These two SNPs may help to predict disease behaviour in CD patients, which may be clinically useful in shaping treatment of the disease at an earlier stage.

Adult↗
PubMed2000

An investigation of language used by children to describe discomfort during dental pulp-testing.

AIM: Studies of the descriptions of pain by children have neglected their linguistic development, therefore estimates of dental pain in children may not be accurate. This study sought (1) to identify words chosen by children to describe dental pain and (2) to establish the effect of linguistic development on that description. SAMPLE: Seventy-eight consecutive children between the ages of 5 and 13 years attending a paediatric dental clinic. METHOD: Each child completed the WORD reading comprehension test. They then underwent a pulp test and a simulated pulp test, administered by a dentist in a counterbalanced order, of a healthy primary canine or permanent incisor, according to the child's age. To describe each test, the children had to (1) select words from a list of 58 read by the experimenter and (2) give ratings on scales representing 'sore' and 'tingly'. RESULTS: Analysis of variance confirmed that the children chose more words for the pulp test than for the simulated test (P < 0.001); the former also elicited higher ratings for 'sore' and 'tingly'. The numbers of words chosen were transformed by a square root constant to ensure a normal distribution. Multiple regression analysis then showed that (1) the better the children's reading comprehension, the fewer words they chose, possibly because they were less inclined to choose unfamiliar words, and (2) the older they were, the more words they chose, possibly because of having more experience of pain. There were similar findings for ratings of 'sore' and 'tingly'. CONCLUSIONS: To assess children's experience of pain (1) they need to be presented with a list of words like the ones in this study, (2) the numbers of words chosen by them would represent the severity of pain, and (3) those numbers need to be adjusted for the children's reading comprehension and age.

Adolescent↗
PubMed2000

Kupffer cells do not play a role in governing the efficacy of liposomal mitoxantrone used to treat a tumor model designed to assess drug delivery to liver.

A tumor model designed to assess liposome-mediated drug delivery to liver has been used in an attempt to better understand the mechanism of activity of liposomal mitoxantrone, a liposomal anticancer drug formulation that appears to be uniquely effective in treating this tumor model. Reductions in liposomal mitoxantrone accumulation in the liver were achieved either by use of poly(ethylene)glycol (PEG)-modified lipids or by methods designed to deplete liver phagocytes, a method referred to as hepatic mononuclear phagocytic system (MPS) blockade. A 2-fold reduction in mitoxantrone delivery to the liver was obtained using a mitoxantrone formulation with PEG-modified lipids, and a 3-fold reduction was obtained when liposomal mitoxantrone was given to animals pretreated to induce hepatic MPS blockade. Results demonstrate that the liposomal mitoxantrone formulation prepared with PEG-modified lipids was significantly less active than the formulations that did not contain PEG lipids, with median survival times of 17 days and 100% 60-day survival, respectively. In contrast, hepatic MPS blockade had no effect on the therapeutic activity of 1,2-dimyristoyl phosphatidylcholine/cholesterol (DMPC/Chol) mitoxantrone (100% 60-day survival). These data suggest that the hepatic MPS does not play a role in mediating the therapeutic activity of DMPC/Chol mitoxantrone in the treatment of liver localized disease. Results with formulations prepared with a PEG-stabilized surface, however, suggest that nonspecific methods to decrease liposome cell interactions inhibit the therapeutic activity of DMPC/Chol mitoxantrone.

Animals↗
PubMed2000

Guided imagery: a strategy for improving relationships and human interaction.

Guided imagery, rather than being a revolutionary complementary or alternative therapy, has been utilised for centuries to alleviate suffering and promote wellness. Its efficacy has been studied and documented in physical, psychological and spiritual dis-ease. This article reviews relevant literature supporting the premise that guided imagery is a strategy that can be used for improving therapeutic relationships and is an example of holistic health care.

Communication↗
PubMed1999

A model for patient participation in quality of life measurement to improve rehabilitation outcomes.

Health-related quality of life (HRQOL) measurement is being used to assess end-stage renal disease (ESRD) patients' functional status and well-being from the patient's perspective. Research shows that HRQOL can screen for patients at high risk for death, hospitalization, treatment adherence, and depression. This study investigated whether patient goal setting and interdisciplinary collaboration and support could increase HRQOL scores in ESRD patients on chronic maintenance hemodialysis. Differences were found to be statistically significant in two of the MOS Short Form 36 (SF-36) categories (role physical and role emotional) following the intervention at the 95% confidence interval using a t-test statistic. This indicates that the intervention had a positive impact on patient perceptions of their health status. Eighty-seven percent indicated that there had been at least some progress made in reaching the goal. The results of this study support the utilization of HRQOL data at the facility level to improve patient's perceptions of their health status. A further study is needed to examine the long-term impact on HRQOL and other patient outcome measures through consistent use of this intervention.

Activities of Daily Living↗
PubMed1998

Paracrine induction of stem cell renewal by LIF-deficient cells: a new ES cell regulatory pathway.

The propagation of pluripotential mouse embryonic stem (ES) cells is sustained by leukemia inhibitory factor (LIF) or related cytokines that act through a common receptor complex comprising the LIF receptor subunit (LIF-R) and the signal transducer gp130. However, the findings that embryos lacking LIF-R or gp130 can develop beyond gastrulation argue for the existence of an alternative pathway(s) governing the maintenance of pluripotency in vivo. In order to define those factors that contribute to self-renewal in ES cell cultures, we have generated ES cells in which both copies of the lif gene are deleted. These cells showed a significantly reduced capacity for regeneration of stem cell colonies when induced to differentiate, confirming that LIF is the major endogenous regulatory cytokine in ES cell cultures. However, self-renewal was not abolished and undifferentiated ES cell colonies were still obtained in the complete absence of LIF. A differentiated, LIF-deficient, parietal endoderm-like cell line was derived and shown to support ES cell propagation via production of a soluble, macromolecular, trypsin-sensitive activity. This activity, which we name ES cell renewal factor (ESRF), is distinct from members of the IL-6/LIF family because (i) it is effective on ES cells lacking LIF-R; (ii) it is not blocked by anti-gp130 neutralizing antibodies; and (iii) it acts without activation of STAT3. ES cells propagated clonally using ESRF alone can contribute fully to chimaeras and engender germline transmission. These findings establish that ES cell pluripotency can be sustained via a LIF-R/gp130-independent, STAT-3 independent, signaling pathway. Operation of this pathway in vivo could play an important role in the regulation of pluripotency in the epiblast and account for the viability of lifr -/- and gp130 -/- embryos.

Animals↗
PubMed1998

The relationship between census-derived socio-economic variables and general practice consultation rates in three town centre practices.

BACKGROUND: The relationship between socio-economic factors and consultation rates is important in determining resource allocation to general practices. AIM: To determine the relationship between general practice surgery consultation rates and census-derived socio-economic variables for patients receiving the same primary and secondary care. METHOD: A retrospective analysis was taken of computerized records in three general practices in Mansfield, North Nottinghamshire, with 29,142 patients spread over 15 electoral wards (Jarman score range from -23 to +25.5). Linear regression analysis of surgery consultation rates at ward and enumeration district levels was performed against Jarman and Townsend deprivation scores and census socio-economic variables. RESULTS: Both the Townsend score (r2 = 59%) and the Jarman score (r2 = 39%) were associated with surgery consultation rates at ward level. The Townsend score had a stronger association than the Jarman score because all four of its component variables were individually associated with increased consultations compared with four out of eight Jarman components. CONCLUSIONS: Even in practices not eligible for deprivation payments there were appreciable differences in consultation rates between areas with different socio-economic characteristics. The results suggest that the variables used to determine deprivation payments should be reconsidered, and they support suggestions that payments should be introduced at a lower level of deprivation and administered on an enumeration district basis.

England↗
PubMed1998

Recognizing and caring for the medically compromised child: 3. Disorders affecting the gastro-intestinal tract and human immunodeficiency virus infection.

Oral manifestations of gastro-intestinal disease are commonly under-diagnosed. This paper is the third in the series entitled 'Recognizing and Caring for the Medically Compromised Child' and seeks to facilitate the process of diagnosis and management of disorders affecting the gastro-intestinal tract in terms of both oral and gut signs and symptoms. This paper concludes with a section devoted to the recognition of HIV disease in paediatric patients, both orally and generally, and its implications for management within the dental surgery.

Child↗
PubMed1997

The use of mediation to manage patient-staff conflict in the dialysis clinic.

The use of mediation to manage a disruptive incident between a staff nurse and a hemodialysis patient is the focus of this multidisciplinary case review. The growing interest in techniques to manage disruptive patient behavior in the dialysis clinic is analyzed. A mediation model designed for the dialysis clinic is presented for the reader. This case presentation also examines the experience of conflict from several perspectives including the patient, the nurse, the nurse manager, and the social worker. This discussion is intended to provide the reader with support for viewing conflict as unavoidable in the chronic dialysis treatment environment and for enlisting the support of the patient when responding to disruption in the treatment relationship.

Adult↗
PubMed1996

Factors influencing the response to advertisements for general practice vacancies.

OBJECTIVES: To investigate the extent of problems in recruiting general practitioners and to determine which practice characteristics affect recruitment--in particular, to see if practices with deprived patients have more recruitment problems. DESIGN: Postal questionnaire survey in August 1995. SUBJECTS: 489 consecutive practices that had advertised for a partner in the BMJ from January to April 1995. MAIN OUTCOME MEASURES: The number of applicants, the practices, satisfaction with their quantity and quality, and whether a successful appointment was made. RESULTS: 442 (90%) practices replied. 262 practices (60%) were not very satisfied or very dissatisfied with the number of applications they received; 15 (3%) received no applications. There was a significant difference in the number of applications received by practices in different NHS regions. The 32 practices with the highest proportions of patients eligible for deprivation payments received a median of five applicants compared with 10 for practices without deprivation. CONCLUSION: There is a widespread problem in recruiting general practitioners. Recruitment is hardest in areas with the greatest health needs.

Advertising↗
PubMed1995

A multivariate analysis of factors related to the mortality of blunt trauma admissions to the North Staffordshire Hospital Centre.

OBJECTIVE: To identify characteristics of blunt trauma admissions associated with mortality and to derive a linear logistic model for predicting the probability of mortality. DESIGN: A prospective observational study. MATERIALS AND METHODS: Data were collected on blunt trauma patients admitted via the Accident and Emergency Department, North Staffordshire Hospital Centre. Univariate and multivariate analyses were performed of potential risk factors associated with mortality. MEASUREMENTS AND MAIN RESULTS: The main outcome variable was survival or death occurring in hospital within 30 days of admission. Injury Severity Score, age, Revised Trauma Score, and place of injury (road traffic, home, or elsewhere) were independently related to mortality. The effect of age on mortality was best described using three categories: 0-64 excluding 15-24, 15-24, 65+. The survival probability model suggests that a person whose injury occurs in the home has a lower probability of survival than a patient with similar age and trauma scores who is involved in a road traffic accident. A model validation check indicated good agreement between model predictions and patient outcomes. CONCLUSIONS: The authors propose that use of this model may provide a more accurate evaluation of the mortality of British trauma admissions than would be obtained using models based on data from American trauma cases.

Adolescent↗
PubMed1992

Assessment and training of functional conversation behaviour.

Measures for the assessment of initial, dyadic conversations are critically reviewed, and an alternative approach is described. The Verbal Interaction Analysis System is illustrated by two case studies featuring mildly to moderately intellectually disabled adults. These studies show how the VIAS provides an index of competence and assists in the development of specific treatment strategies. Social validity is examined in each case, and suggestions are made for improvements to the VIAS.

Adult↗