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Biomedical subjects

S Dickson

Publications and source records attributed to S Dickson.

At least 19 recordsLinked to original sources
PubMed2002

Improvement in cholestasis associated with total parenteral nutrition after treatment with an antibody against tumour necrosis factor alpha.

BACKGROUND: Many patients receiving long-term total parenteral nutrition (TPN) develop liver disease; cholestasis is common and may be severe. Antitumour necrosis factor alpha (TNFalpha) antibodies have recently been used in order to treat Crohn's disease, but their effect on cholestasis in humans has not been previously described. CASE REPORT: A 45-year-old woman had complicated Crohn's disease with multiple fistulae and only 1 m of residual small bowel. She had been receiving TPN for 2.5 years when she developed cholestasis which worsened despite adjustments to her TPN regimen. Infliximab, an anti-TNFalpha antibody, was given with the aim of treating an enterocutaneous fistula, but it also produced a marked biochemical and histological improvement in the TPN-related cholestasis. CONCLUSIONS: Anti-TNFalpha antibodies appeared in this case to improve TPN-related cholestasis. This implies that TNFalpha may play an important role in the development of this condition.

Antibodies, Monoclonal↗
PubMed2002

Exposure of hospitality workers to environmental tobacco smoke.

OBJECTIVE: To determine quantitatively the extent of exposure of hospitality workers to environmental tobacco smoke (ETS) exposure during the course of a work shift, and to relate these results to the customer smoking policy of the workplace. SUBJECTS: Three categories of non-smoking workers were recruited: (1) staff from hospitality premises (bars and restaurants) that permitted smoking by customers; (2) staff from smokefree hospitality premises; and (3) government employees in smokefree workplaces. All participants met with a member of the study team before they began work, and again at the end of their shift or work day. At each meeting, participants answered questions from a standardised questionnaire and supplied a saliva sample. MAIN OUTCOME MEASURES: Saliva samples were analysed for cotinine. The difference between the first and second saliva sample cotinine concentrations indicated the degree of exposure to ETS over the course of the work shift. RESULTS: Hospitality workers in premises allowing smoking by customers had significantly greater increases in cotinine than workers in smokefree premises. Workers in hospitality premises with no restrictions on customer smoking were more highly exposed to ETS than workers in premises permitting smoking only in designated areas. CONCLUSIONS: Overall, there was a clear association between within-shift cotinine concentration change and smoking policy. Workers in premises permitting customer smoking reported a higher prevalence of respiratory and irritation symptoms than workers in smokefree workplaces. Concentrations of salivary cotinine found in exposed workers in this study have been associated with substantial involuntary risks for cancer and heart disease.

Adult↗
PubMed1999

The double helix is dehydrated: evidence from the hydrolysis of acridinium ester-labeled probes.

A highly chemiluminescent reporter molecule, acridinium ester (AE), was tethered to single-stranded oligonucleotide probes and hybridized to complementary as well as mismatched target sequences. When tethered to single-stranded probes, AE was readily hydrolyzed by water or hydroxide ion. In contrast, when hybridized to a complementary target, hydrolysis of the AE probe was markedly inhibited. Mismatches near AE eliminated the ability of the double helix to strongly inhibit AE hydrolysis. To establish the molecular basis for these remarkable hydrolysis properties of AE-labeled probes, the binding and hydrolysis mechanisms of AE-labeled probes were examined. When tethered to single- or double-stranded nucleic acids, hydrolysis of AE was found to proceed by generalized base catalysis in which a base abstracts a proton from water and the resulting hydroxide ion then hydrolyzes AE. Analysis of the hydrolysis rates of AE bound to DNA revealed that AE binds the minor groove of DNA and that its hydrolysis is inhibited by low water activity within the minor groove of the helix. Depending upon the sequence of the DNA, the water activity of the minor groove was estimated to be at least 2-4-fold lower than bulk solution. Hydrolysis measurements of AE tethered to RNA as well as RNA/DNA hybrids argued that the grooves of these double helices are also dehydrated relative to bulk solution. Remarkably, mismatched bases, regardless of their structure or sequence context, enhanced hydrolysis of AE by inducing hydration of the double helix that spread approximately five base pairs on either side of the mismatch.

Acridines↗
PubMed1997

Using neural networks to automatically detect brain tumours in MR images.

Computer vision has been applied to many medical imaging problems with the aim of providing clinical tools to aid medical professionals. We present work being carried out to develop one such system to automatically detect a specific type of brain tumour from head MR images. The tumour under consideration is an acoustic neuroma, which is a benign tumour occurring in the acoustic canals. The hybrid system developed integrates neural networks with more conventional techniques used for computer vision tasks. A database of MR images from 50 patients has been assembled and the acoustic neuromas present in the images have been labelled by hand. Using this data, neural networks (MLPs) have been developed to classify the images at the pixel level to achieve a targeted segmentation. The data used to train and test the MLPs developed, consists of the grey levels of a square of pixels, the pixel to be classified being the centre pixel, together with its global position in the image. The initial pixel level segmentation is refined by a series of conventional techniques. It is combined with an edge-region based segmentation and a morphological operation is applied to the result. This processing produces clusters of adjacent regions, which are considered to be candidate tumour regions. For each possible combination of these regions, features are measured and presented to neural networks which have been trained to identify structures corresponding to acoustic neuromas. Using this approach, all the acoustic neuromas are identified together with three false positive errors.

Automation↗
PubMed1997

Towards equity in long-term care.

There are considerable similarities and overlap in the levels of disability and dependency between those who receive home-based-long-term care and those who receive long-term care on a residential basis. These similarities are demonstrated from analysis of clients of the Western Domiciliary Care and Rehabilitation Service. When services are costed, it is shown that there is a very large discrepancy in the levels of government support that clients of home-based care agencies attract compared to residents in subsidised hostels and nursing homes. This paper discusses the need for parity of funding to care providers and recognition of the economic value of the contributions of carers. It considers principles for the development of a casemix model for home-based care analogous to the Care Aggregated Module/Standard Aggregated Module (CAM)/(SAM) model applying to nursing home care.

Aged↗
PubMed1995

Clinical effects of recent cocaine use on patients with acute schizophrenia.

OBJECTIVE: Dopamine function has been hypothesized to be involved in both producing schizophrenic symptoms and mediating cocaine's reinforcing properties. As a result, cocaine abuse in schizophrenic patients may be seen as a natural experiment that may alter the phenomenology and neurobiology of schizophrenia. This report concerns the clinical effects of cocaine abuse and cessation in schizophrenic patients at two times: when patients presented to the psychiatric emergency service and again after 4 weeks of hospitalization. METHOD: The subjects were 15 cocaine-abusing and 22 cocaine-abstaining schizophrenic patients. Diagnostic assessments were performed with the Structured Clinical Interview for DSM-III-R--Patient Version, which uses DSM-III-R criteria. All of the patients were assessed at both times with the Brief Psychiatric Rating Scale, the Scale for the Assessment of Positive Symptoms, and the Scale for the Assessment of Negative Symptoms. RESULTS: Cocaine-abusing schizophrenic patients showed fewer negative signs and more anxiety/depression at the hospital-admission assessment than their nonabusing counterparts. At retest, no group differences were detected in patients' negative signs or mood symptoms. Severity of positive symptoms was equal at both testing sessions. CONCLUSIONS: The significant difference in negative signs and mood symptoms at admission assessment was attributed to the neurobiological impact of cocaine. The role of psychostimulants in schizophrenic patients is discussed.

Acute Disease↗
PubMed1978

Aerodynamic studies of cleft-palate speech.

The aerodynamic oral-nasal factors related to the speech of two groups of cleft-palate children were evaluated. One group presented hypernasality and the other group presented normal nasal resonance. The aerodynamic parameters evaluated were oral pressure, nasal flow, and flow-pressure ratio (nasal flow/oral pressure). Oral temperature readings were also obtained. These parameters were evaluated under three conditions (1) blowing, (2) vocalizing the vowel /i/, and (3) reading eight sentences representing two different rhythm patterns, two types of consonant loadings, and two conditions of syllable stress. The findings revealed significant differences between the hypernasal and normal resonance groups in flow-pressure ratio, oral pressure, and nasal flow while subjects were reading sentences. However, only a small proportion of the variability in these aerodynamic measurements could be accounted for based on the classification of hypernasality or normal nasal resonance. Oral-nasal aerodynamic studies done during speaking activity are more useful clinically than blowing activity or saying vowel sounds. No aerodynamic differences were noted between the two groups for the different rhythm and stress patterns and phonemic loadings within the sentences used.

Adolescent↗
PubMed1975

Dental attitudes and behavior related to vertical social mobility by marriage.

Following a dental examination of 5-year-old children, the mothers of 367 of them were interviewed. In 262 cases there was sufficient information relating to the social class of both the mother's husband and her father to enable the relationship between social mobility by marriage and the mother's dental attitudes and behavior to be assessed. The results showed that the views of mothers who moved from one social group to another fell between those of the mothers who were static in each of those two groups. Those mothers who were downward mobile had less favorable attitudes than those who had remained in the higher social group but more favorable than those who had always been in the lower social group. The reverse trend was found in upward mobile mothers. A notable exception to this pattern was the group who moved from social Class III into Class I or II. These mothers exhibited attitudes and behavior which were even more favorable than the static social Class I or II mothers. The similarity of these results to those of others in different fields is discussed.

Attitude to Health↗