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Biomedical subjects

S Jackson

Publications and source records attributed to S Jackson.

At least 37 records · Page 2Linked to original sources
PubMed2003

Preliminary investigations into possible resistance to oxytetracycline in Melissococcus plutonius, a pathogen of honeybee larvae.

AIMS: To investigate the occurrence of oxytetracycline (OTC) resistance in Melissococcus plutonius, which causes European foulbrood in honeybee colonies. METHODS AND RESULTS: Strains of M. plutonius were isolated from diseased colonies in England and Wales and tested for resistance to OTC. The minimum inhibitory concentration (MIC) of OTC was also determined for selected isolates. No resistance to the antibiotic was found in any isolate and the average MIC was found to be 3.9 microg ml-1. Melissococcus plutonius was found to be susceptible to both chlortetracycline and tetracycline. CONCLUSIONS: No resistance to OTC was found in M. plutonius. SIGNIFICANCE AND IMPACT OF THE STUDY: This study demonstrated that OTC can continue to be used to treat European foulbrood and that resistance may not explain why some treatments fail.

Animals↗
PubMed2002

Reduced apoptotic levels in squamous but not basal cell carcinomas correlates with detection of cutaneous human papillomavirus.

We have investigated the apoptotic levels and expression of the apoptotic inducer Bak in non-melanoma skin cancers. Squamous cell carcinomas of known human papillomavirus status from immunocompetent patients were analysed for the expression of the Bak protein, and the expression profile was compared both to the presence of apoptotic cells and the proliferation marker Ki-67. We demonstrate an inverse correlation between human papillomavirus positivity and Bak expression in squamous cell carcinomas, with concomitantly fewer apoptoic cells being detected in the human papillomavirus positive tumours. Bak expression was not observed in basal cell carcinomas irrespective of human papillomavirus status, suggesting that Bak only plays a role in signalling apoptosis in squamous, but not basal, cell cancers. No differences were observed in the proliferation rates between papillomavirus positive and negative squamous cell tumours. However, a significant decrease in the number of apoptotic cells was observed in human papillomavirus-positive squamous cell carcinomas which suggests that the virus may have significantly altered the relationship between proliferation and apoptosis in a proportion of these tumours.

Apoptosis↗
PubMed2002

Use of resistance-area product derived from Doppler MCA velocity to estimate the range of active cerebrovascular regulation.

The purpose of the present study was to explore the development of a method to estimate the range of active cerebrovascular regulation using resistance-area product (RAP) derived from transcranial Doppler ultrasound recordings of middle cerebral artery blood velocity (MCAV) obtained before and after physiologic challenge. Intracranial pressure (ICP), arterial blood pressure (ABP), and MCAV were monitored on 9 patients before and after challenges with either Noradrenlin or CO2 inhalation. One patient was monitored at 24, 48, 72, and 96 hrs. For each cardiac cycle a value of RAP was computed from the inverse of the slope of the regression line of paired values of aligned MCAV and ABP recordings. Mean values of percent change of difference of RAP (% delta RAP) versus change of cerebral perfusion pressure (CPP) were computed. Theoretical values of % delta RAP were derived from reported lab values of percent change diameter of arterioles versus ABP. Of the nine patients, 22% (2/9) demonstrated either impaired dilation and/or constriction. Furthermore, the correlation between theoretical and experimental values of % delta RAP and CPP (n = 34) was strong (r = .86, p < .005). The serially-monitored patient failed to dilate during all CO2 challenges and to fully constrict to the Noradrenlin challenge at 72 hrs. % delta RAP associated with corresponding changes of CPP may have value as a clinical method to estimate the range of active cerebrovascular regulation.

Adolescent↗
PubMed2002

Transferring people safely with manual handling equipment.

OBJECTIVE: To determine whether transferring equipment designed to assist a carer when moving someone who is able to take some weight through their legs is likely to affect the risk of back problems in the carer. DESIGN: Twelve pieces of equipment were tested by nurses transferring patients from commode to wheelchair and vice versa, and from wheelchair to bed and vice versa. Video recordings were taken of each transfer and freeze-frame pictures at the moment of greatest load were analysed. Compressive disc force was deduced, using a biomechanical model, from the weights of the patient and nurse and measurements of anatomical distances and angles. SETTING: The Sir Walter Puckey Gait Laboratory, in the Rehabilitation Research Unit, University of Southampton. SUBJECTS: Six female trained nurses with no recent history of hernia, back pain or pregnancy during the previous six months were recruited to use the equipment. Two female patients were chosen from those volunteering and screened for stroke, confusion and unusual footwear. The patients were able to partially weight-bear and were used to being transferred. RESULTS: The results indicate that the critical value of 3.4 kN at the L5/S1 disc (specified by the US National Institute for Occupational Safety and Health) was not exceeded when using transferring equipment. CONCLUSION: In this study, loading on the spine during transferring tasks with or without equipment was not considered harmful when good technique was employed.

Back Injuries↗
PubMed2002

Blindness following medial maxillectomy.

Medial maxillectomy via lateral rhinotomy approach is used in the treatment for tumours affecting the lateral nasal wall. The most frequent complications are crusting, epicanthal scarring and epiphora. The authors report a rare case of blindness secondary to indirect optic neuropathy following medial maxillectomy undertaken to treat a malignant melanoma arising in the lateral nasal wall. It is important to keep in mind, the possibility of this rare complication, while patients are being counselled preoperatively for medial maxillectomy.

Aged↗
PubMed2001

Influence of plasma glutathione levels on radiation mucositis.

PURPOSE: To test the hypothesis that there is a link between plasma glutathione (GSH) or other antioxidants (uric acid, ascorbate) and the severity of radiation mucositis following radiation treatment of tumors of the head and neck. PATIENTS AND METHODS: Patients with carcinomas of the head-and-neck region were treated with the continuous hyperfractionated accelerated radiotherapy (CHART) regimen (54 Gy in 36 fractions over 12 days). Samples of blood plasma were analyzed for GSH, cysteine, urate, and ascorbate by high-pressure liquid chromatography. Patients were graded for dysphagia and requirement for analgesics. The areas under the curves of scores over 2-6 weeks following treatment were computed, and Spearman's rank-correlation coefficient was used to test for an association between plasma GSH levels (or those of other antioxidants) and mucositis. RESULTS: The pretreatment plasma GSH level in 18 patients scored in the study was 1.0 +/- 0.7 M. Analysis of these and the dysphagia scores produced a correlation coefficient of 0.22 (confidence interval -0.28, 0.61; p = 0.39). No correlation was seen between mucositis severity and other measures of plasma antioxidants: cysteine (7.6 +/- 1.7 M), cysteine + GSH (8.6 +/- 1.9 M), uric acid (317 +/- 86 M), ascorbate (29 +/- 20 M), or whole-blood GSH concentrations (1,010 +/- 239 M). CONCLUSION: The measurements of approximately micromolar levels of plasma GSH, or about 10 M cysteine + GSH (almost all of the total nonprotein thiols), are consistent with most other published data for either healthy adults or cancer patients; however, the values reported in an earlier study, suggesting a link between GSH and mucositis, are much higher. The hypothesis of a possible link between radiation mucositis and plasma-free (nonprotein) thiols was not supported.

Ascorbic Acid↗
PubMed2001

Involvement in caregiving and adjustment to death of a spouse: findings from the caregiver health effects study.

CONTEXT: Most deaths in the United States occur among older persons who have 1 or more disabling conditions. As a result, many deaths are preceded by an extended period during which family members provide care to their disabled relative. OBJECTIVE: To better understand the effect of bereavement on family caregivers by examining predeath vs postdeath changes in self-reported and objective health outcomes among elderly persons providing varying levels of care prior to their spouse's death. DESIGN AND SETTING: Prospective, population-based cohort study conducted in 4 US communities between 1993 and 1998. PARTICIPANTS: One hundred twenty-nine individuals aged 66 to 96 years whose spouse died during an average 4-year follow-up. Individuals were classified as noncaregivers (n = 40), caregivers who reported no strain (n = 37), or strained caregivers (n = 52). MAIN OUTCOME MEASURES: Changes in depression symptoms (assessed by the 10-item Center for Epidemiological Studies-Depression [CES-D] scale), antidepressant medication use, 6 health risk behaviors, and weight among the 3 groups of participants. RESULTS: Controlling for age, sex, race, education, prevalent cardiovascular disease at baseline, and interval between predeath and postdeath assessments, CES-D scores remained high but did not change among strained caregivers (9.44 vs 9.19; P =.76), while these scores increased for both noncaregivers (4.74 vs 8.25; F(1,116) = 14.33; P<.001) and nonstrained caregivers (4.94 vs 7.13; F(1,116) = 4.35; P =.04). Noncaregivers were significantly more likely to be using nontricyclic antidepressant medications following the death than the nonstrained caregiver group (odds ratio [OR], 12.85; 95% confidence interval [CI], 1.02-162.13; P =.05). The strained caregiver group experienced significant improvement in health risk behaviors following the death of their spouse (1.47 vs 0.66 behaviors; F(1,118) = 20.23; P<.001), while the noncaregiver and nonstrained caregiver groups showed little change (0.27 vs 0.27 [P =.99] and 0.46 vs 0.27 [P =.39] behaviors, respectively). Noncaregivers experienced significant weight loss following the death (149.1 vs 145.3 lb [67.1 vs 65.4 kg]; F(1,101) = 8.12; P =.005), while the strained and nonstrained caregiving groups did not show significant weight change (156.2 vs 155.2 lb [70.3 vs 69.8 kg] [P =.41] and 156.2 vs 154.0 lb [70.3 vs 69.3 kg] [P =.12], respectively). CONCLUSIONS: These data indicate that the impact of losing one's spouse among older persons varies as a function of the caregiving experiences that precede the death. Among individuals who are already strained prior to the death of their spouse, the death itself does not increase their level of distress. Instead, they show reductions in health risk behaviors. Among noncaregivers, losing one's spouse results in increased depression and weight loss.

Aged↗
PubMed2001

In vitro exposure to highly cytopathic HIV-1 X4 strains increases expression of mucosa-associated integrins on CD4(+) T cells.

To determine whether infection with HIV-1 strains of different tropisms would influence expression of the mucosa-associated integrins alpha 4 beta 7 and alpha E beta 7 or the lymph node homing receptor L-selectin on peripheral T lymphocytes, cells were infected with the CXCR4-tropic (X4)/syncytium-inducing (SI) HIV-1(IIIB) strain or with X4/SI or CCR5-tropic (R5)/non-SI (NSI) primary human isolates. Flow cytometric analyses of CD4(+) T cells from cultures infected with HIV-1(IIIB) and one X4/SI primary HIV-1 isolate revealed a significant increase in surface expression of alpha 4 beta 7 and alpha E beta 7 12 days after infection. L-selectin expression was not significantly affected on CD4(+) T cells. However, infection with another X4/SI and two R5/NSI primary HIV-1 isolates did not significantly alter homing receptor expression on CD4(+) T cells. Since a higher degree of CD4 cytopathicity occurred in those cultures having increased integrin expression, these data suggest that significantly altered mucosal homing receptor expression on CD4(+) T cells may result as a "bystander" effect after infection with some cytopathic isolates of HIV-1.

CD4-Positive T-Lymphocytes↗
PubMed2001

Two's a crowd.

Explore the source record for details and available documents.

Delivery Rooms↗
PubMed2001

Application of on-site solid-phase microextraction in aquatic dissipation studies of profoxydim in rice.

The application of a manual operated solid-phase microextraction (SPME)-HPLC interface is discussed for the analysis of thermally labile analytes in aqueous matrices. The technique has been applied on-site at a flooded rice field to demonstrate its potential for real time extraction of the herbicide profoxydim. Thus, compounds which would otherwise easily degrade in the aqueous matrices within hours or days could be determined more accurately. The fibers were shipped back to the laboratory with express delivery where the target analyte was desorbed from the fiber and determined by HPLC-UV analysis. The SPME method was characterized by significant ruggedness where conventional techniques such as liquid-liquid extraction and solid-phase extraction require additional shipping and handling costs and time-consuming multiple sample preparation steps. In general, any delay in shipping the aqueous samples to the laboratory has the potential for sample degradation and a loss in accuracy when using non on-site extraction techniques. Fifty microm Carbowax-templated resin coatings were most suitable for coupling SPME to HPLC in order to achieve a high sensitivity for polar analytes. The SPME technique was characterized by a good sensitivity and a precision less than 10% RSD. The SPME-LC-UV method was linear over at least three orders of magnitude while achieving a limit of detection in the lower microg/l range. The on-site SPME method has shown significantly increased accuracy. Profoxydim was determined at concentrations of ca. 180 microg/l 3 h after an application on a flooded bare soil field.

Benzene Derivatives↗
PubMed2001

Depression in older people with mild stroke, carotid stenosis and peripheral vascular disease: a comparison with healthy controls.

BACKGROUND: Although depression has a recognised association with stroke, the role of "silent" cerebrovascular pathology associated with carotid stenosis and peripheral vascular disease remains unexplored. METHODS: Four groups of 25 community residents aged 65 and over were recruited, comprising first anterior circulation stroke, carotid stenosis accompanied by transient ischaemic attack, peripheral vascular disease and a non-vascular control group. All participants were interviewed using the Hamilton Rating Scale for Depression [HRSD] (including a modified version) and Geriatric Depression Scale. DSM IV criteria for major depression and measures of handicap, social support and physical illness were also administered. Head computerised tomography (CT) scans were performed on stroke patients to examine the relationship between lesion location and depression. RESULTS: One hundred patients were interviewed. Stroke patients were more likely to live in a nursing home and had less social support than other groups. Mean scores on the modified Hamilton and Geriatric Depression Scales were higher in stroke and carotid stenosis groups than controls. Patients with stroke did not show a higher prevalence of DSM IV major depressive disorder than those with carotid stenosis. There was no relationship between the presence of lesions affecting the frontal/subcortical system and prevalence/severity of depression. LIMITATIONS: Small numbers, mortality of stroke patients in hospital, possible selection bias in the control group and use of a previously unvalidated depression rating scale all limit the study. CONCLUSIONS: A possible role for carotid stenosis in the pathogenesis of depressive disorder is suggested. Larger studies incorporating brain imaging may be required to examine the mechanism of this association more closely. The use of a shorter version of the HRSD in older people with cerebrovascular disease may warrant further exploration.

Aged↗
PubMed2001

Cognitive strategies employed in trying to arrange a first date.

This article deals with how adolescents go about making a date. It uses a funnelling approach to elicit information which is then studied in more detail in a series of further steps. Study 1 used a short survey to obtain data concerning subjects' (n=410) experience of dating. Thereafter, 47 of these subjects selected situations and actions relevant to their dating experience, from two specially prepared lists. Study 1 provided information concerning the relevance of the lists, their comprehensibility and the frequency with which subjects had encountered specific situations or actions. In Study 2, 287 subjects completed the survey, 73 were selected and given revised versions of the lists. After selecting situations and actions, they were interviewed concerning their choice. Subject's responses are discussed with respect to social cognitive development in adolescence.

Adolescent↗
PubMed2001

Coagulation factor activity during neonatal extra-corporeal membrane oxygenation.

OBJECTIVE: To ascertain the activity of major coagulation factors during the first 24 h of extra-corporeal membrane oxygenation (ECMO) used to support hypoxaemic neonates. DESIGN AND SETTING: A prospective observational study in a regional centre for ECMO and paediatric cardiac surgery, placing 15-20 neonates on ECMO per year. PATIENTS: Ten neonates receiving ECMO for severe hypoxaemia. MEASUREMENT AND RESULTS: The activity of major clotting factors, of the inhibitor anti-thrombin III and of markers of blood activation were measured during the first 24 h of neonatal extra-corporeal membrane oxygenation (ECMO) and prior to initiation of ECMO. There was laboratory evidence of factor deficiency and of activation of coagulation at all stages. The initiation of ECMO leads to an initial worsening of coagulopathy, but factor deficiency and abnormal activation of coagulation is also seen prior to ECMO in these very sick neonates. CONCLUSION: If factor deficiency is to be avoided a pro-active approach is required to rapidly correct factor activity. This would include the use of fresh frozen plasma. The effect of such an approach on outcome is at yet uncertain.

Biomarkers↗