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Biomedical subjects

P Jennings

Publications and source records attributed to P Jennings.

At least 19 recordsLinked to original sources
PubMed2006

Application of a population balance model to a perfusion in vitro toxicity system.

Perfusion cell culture is different to static cell culture: In perfusion culture, steady state concentrations of nutrients and metabolites can be achieved. When a toxin is added to the medium, it is administered to the cells at a defined constant concentration. Perfusion culture is favourable for time series analysis of experimental data because assays can be performed online in the outflowing medium at a high time resolution. The cytotoxicity exerted by cadmium chloride (CdCl(2)) on LLC-PK(1) cells was investigated in static and in perfusion culture using the EpiFlow system in order to compare both the techniques. For this comparison, cytotoxicity was assessed by the release of the cytosolic enzyme lactate dehydrogenase (LDH), and by the potential of viable cells to reduce resazurin. The results showed a greater sensitivity of LLC-PK(1) monolayers to CdCl(2) with continuous exposure in perfusion culture as compared to a single or repeated dose in static culture, as evidenced by increased LDH release and decreased resazurin reduction. These differences between static and perfusion culture were ascribed to different delivery rates of toxin to the site of absorption. Cadmium accumulation of the cells was measured and found to be higher under perfusion conditions than under static conditions. Time series analysis of the LDH release in perfusion culture was performed by establishing a deterministic population balance model of cell death. An empirical death rate function that accounts for accumulation of the toxin was introduced and could be successfully verified.

Algorithms↗
PubMed2006

A fluorescent microplate assay for exocytosis in alveolar type II cells.

The authors describe a simple, reliable, and quantitative assay to monitor exocytotic fusion of lamellar bodies (LBs) in adherent rat alveolar type II (AT II) cells. The assay is based on fluorescence measurements of LB-plasma membrane (PM) fusions modified for the use in multiwell culture plates to obtain a high-sample throughput. In particular, it is based on the presence of a highly light-absorbing dye in the cell supernatants to increase the specificity of fluorescence signals and to yield pseudo-confocal information from the cells. When the assay was tested with agonist-(ATP) and phorbolester-induced stimulation of LB-PM fusions, the authors found a good correlation with direct microscopic investigations based on single cell recordings. To further validate the assay, they used Curosurf at 10 mg/ml. However, it influenced neither the basal nor the ATP-stimulated rate of LB-PM fusions. This was corroborated by the fact that Curosurf had no effect on resting Ca (2+) levels nor the ATP induced Ca (2+) signals. The results cast new light on previous findings that surfactant phospholipids decrease the rate of secretion in AT II cells in a dose-dependent way. The authors conclude that the inhibitory effect exerted by phospholipids might be due to action on a later step in exocytosis, probably associated with exocytotic fusion pore expansion and content release out of fused vesicles.

Adenosine Triphosphate↗
PubMed2003

Haemodynamic and electrocardiographic consequences of severe nicorandil toxicity.

A 35 year old woman was admitted to the emergency department two hours after ingesting 60x20 mg tablets of nicorandil, total 1.2 g. The dominant feature of icorandil toxicity was profound peripheral vasodilatation associated with coronary hypoperfusion. Despite widespread electrocardiographic signs of myocardial ischaemia, there was no evidence of myocardial damage and no serious cardiac arrhythmia. Volume loading and pressor support proved to be an effective treatment strategy.

Adult↗
PubMed2002

Role of computerized tomography (CT) scan of the chest in patients with newly diagnosed head and neck cancers.

Chest metastases and second primaries are not uncommon in patients with head and neck cancer. Early detection of a second site of malignant disease may alter prognosis and management. This study assessed the diagnostic yield of chest radiographs compared with computerized tomography (CT) in a series of patients with head and neck cancer. Forty-four consecutive patients with a head and neck squamous cell carcinoma (SCC) attending the head and neck surgery department of Cumberland Infirmary, Carlisle, between January 2000 and December 2000 were included in this prospective study. Patients with lymphomas and localized cancers of the skin and lip were excluded. Thirty men and 14 women, with a mean age of 67 years, were assessed. All had chest radiographs and chest CT at the same time as the CT scan of the primary site. Only one patient had a true positive finding on chest radiograph. Five patients had an abnormal chest CT. Of these, two had multiple lung metastases, and another patient had biopsy-proved bronchogenic carcinoma and underwent surgical excision. The sensitivity and specificity of CT scan was 100% and 95%, as opposed to 33% and 97% for chest radiograph.

Aged↗
PubMed2002

Should paediatric units have bereavement support posts?

Eight bereavement support posts in paediatrics and maternity were established using the experience of the Child Bereavement Trust (CBT). Evaluation showed that staff welcomed the informal support and teaching for themselves, as well as support for families; 67% of staff who returned questionnaires felt care for bereaved families had improved as a result of the posts. Many felt that there had been a positive effect on staff retention and stress levels.

Attitude of Health Personnel↗
PubMed2001

Survival from out-of-hospital cardiac arrest in the Geelong region of Victoria, Australia.

OBJECTIVE: To study the outcome from prehospital cardiac arrest managed by ambulance personnel, and to examine overall survival rates from successful resuscitation. METHODS: A retrospective analysis was made of 115 patient care records of prehospital cardiac arrests with attempted resuscitation between July 1996 and September 1999. All cases had a presumed primary cardiac cause for their cardiac arrest. RESULTS: Overall survival, defined as admitted to hospital alive, was 22 subjects (19.1%), with five subjects (4.3%) being discharged from hospital neurologically intact. Of the patients who survived to the emergency department, six (5%) had initially presented in pulseless electrical activity and 16 (14%) presented with ventricular fibrillation. No patients presented with ventricular tachycardia and no survivors presented in asystole. Median response interval from time of call to arrival of initial crew at patient's side was 9 min. No patients survived when response interval was greater than 14 min. Bystander cardiopulmonary resuscitation was being performed on 55 patients (48%) on arrival of initial ambulance crew; 68.2% of patients surviving to hospital having had bystander cardiopulmonary resuscitation. CONCLUSION: Decreasing time delays in accessing the patient is crucial to improving outcome in out-of-hospital cardiac arrest.

Adolescent↗
PubMed2000

Guidelines for the management of women with abnormal cervical smears 1998.

Four important changes have been introduced in the revised guidelines for the management of women with abnormal cervical smears, 1998. 1. For the purposes of management, atypical squamous cells of undetermined significance (ASCUS) and atypical glandular cells of undetermined significance (AGUS) have been included with low grade squamous intraepithelial lesions (LSIL/CIN1/HPV) except where the smear raises the possibility of a high grade squamous intraepthelial lesion (HSIL) or favours glandular dysplasia. 2. Women with low grade cytological and histological intraepithelial abnormalities will, after initial follow-up, revert to three yearly screening. 3. Requirements for those practising colposcopy have been defined. 4. A formal review of all cases of invasive cervical cancer is advocated.

Adenocarcinoma↗
PubMed2000

Sarcoplasmic reticulum Ca(2+)-ATPase of sea cucumber smooth muscle: regulation by K(+) and ATP.

Although several Ca(2+)-ATPase isoforms have been described in vertebrates, little is known about Ca(2+)-transport in the muscle of invertebrates. In the microsomal fraction obtained from the sea cucumber (Ludwigothurea grisea) longitudinal body wall smooth muscle, we identified a Ca(2+)-transport ATPase that is able to transport Ca(2+) at the expense of ATP hydrolysis. This enzyme has a high affinity for both Ca(2+) and ATP, an optimum pH around 7.0, and - different from the vertebrate sarcoplasmic reticulum Ca(2+)-ATPases isoforms so far described - is activated 3- to 5-fold by K(+) but not by Li(+), at all temperatures, Ca(2+) and ATP concentrations tested. Calcium accumulation by the sea cucumber microsomes is inhibited by Mg/ATP concentrations >1 mM and the accumulated Ca(2+) is released to the medium when the ATP concentration is raised from 0.1 to 4.0 mM.

Adenosine Triphosphate↗
PubMed1995

Postnatal development of the calcium-dependency of glutamate release from rat cortical synaptosomes: comparison with 5-hydroxytryptamine release.

The ontogeny of the Ca(2+)-dependency of the depolarisation-induced release of preloaded [3H]glutamate and [3H]5-hydroxytryptamine [5-HT] from rat cortical synaptosomes was examined. 5-HT release was found to be exclusively Ca(2+)-dependent at all ages studied. In contrast, glutamate release only showed a significant Ca(2+)-dependent component from postnatal day 10 [PND 10] onwards. This correlated with the ontogeny of the glutamate accumulating activity of synaptic vesicles, a finding consistent with vesicles being the site of Ca(2+)-dependent release. The effectiveness of K(+)-depolarisation in inducing the Ca(2+)-dependent release of both transmitters increased during the early neonatal period, reaching near adult levels at PND20 for 5-HT and PND30 for glutamate.

Animals↗
PubMed1995

Epilepsy and children's social and psychological adjustment.

This research investigates the effects of epilepsy on the social and psychological adjustment of the children studied in the National Health Interview Survey of 1988. Analyses examine the effect of epilepsy on four measures of adjustment--home behavior problems, school behavior problems, depressed mood, and impulsiveness. For each outcome, we address five questions: (1) Do children with currently active epilepsy have poorer adjustment than children with inactive epilepsy? (2) Do children with epilepsy fare worse than other children? (3) Do demographic background and family structure moderate the apparent effects of epilepsy? (4) Do family processes mediate the apparent effects of epilepsy? and (5) Do cooccurring conditions produce the apparent effects of epilepsy? Generally, we find that: (1) Children with active and inactive epilepsy fare about equally; (2) Children with any history of epilepsy fare worse than children without epilepsy; (3) Demographic and family background moderate only a small part of epilepsy's effect; and (4) A combination of family processes and cooccurring conditions appears to produce epilepsy's apparent effects.

Adaptation, Psychological↗
PubMed1995

Pick and mix.

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Curriculum↗
PubMed1995

Oxidative stress is present in atherosclerotic peripheral arterial disease and further increased by diabetes mellitus.

OBJECTIVE: Atherosclerosis, which is associated with increased oxidative stress, may be widespread and more advanced in both complicated and uncomplicated diabetics than in healthy, age-matched non diabetic controls. The development of microangiopathy and the early development of microangiopathy and the early development of macroangiopathy which occurs in diabetes have unclear aetiology. We have previously shown an increase in the products of free radical activity in conventional atherosclerosis and this study has considered whether there us a further increase in this oxidative stress in diabetics. EXPERIMENTAL DESIGN: We measured oxidation by free radicals as lipid peroxides (malondialdehyde) and plasma thiols in 19 insulin dependent diabetic patients with retinopathy or microproteinuria but no clinical evidence of large vessel disease, 19 non diabetic patients with obstructive peripheral arterial disease confirmed by angiography and 19 asymptomatic matched healthy control subjects. PATIENTS: The patients were recruited from either the local diabetic or vascular surgery clinics. RESULTS: There were significant increases in oxidative stress in diabetic patients compared to control subjects with increased malondialdehyde 9.2 mumol/l (7.1-11.2) versus 7.65 mumol/l (5.4-9.6, p < 0.01 Mann Whitney test) and reduced plasma thiols 458 mumol/l (294-595) versus 506 mumol/l (433-589, p < 0.05). Those non-diabetic patients with obstructive peripheral arterial disease also had significantly increased malondialdehyde levels at 8.4 mumol/l (6.5-10.1, p < 0.05) and reduced plasma thiols 435 mumol/l (361-462, p < 0.05) compared to controls. The difference between patients with conventional atherosclerotic peripheral arterial disease and those with additional diabetes was significant for malondialdehyde (p < 0.05). CONCLUSIONS: These data confirm the oxidative stress that exists in atherosclerotic peripheral arterial disease and suggest that diabetic patients with microangiopathy have an increase in this oxidative stress which may contribute to their early development of atherosclerosis.

Adult↗
PubMed1994

Learning through experience: an evaluation of 'Hospital at Home'.

A Hospital at Home service for children was begun in April 1991 in a rural health authority in England. After 18 months a mainly qualitative evaluation has shown that the children and parents concerned have been very satisfied with the service and would choose the same type of care again. General practitioners and health visitors felt it was to the benefit of the whole family for the child to be at home while ill. They acknowledge a high standard of care received by the children but were critical of poor liaison between hospital and community and the loose arrangements for medical responsibility. These areas of strength and weakness are known to have been experienced in other districts establishing paediatric home care. Here, proposals have been made to improve the weaker aspects of the service as a direct response to the evaluation. These are now being put into practice, with one new appointee already in post. It is suggested that the proposals are applicable to other districts planning similar services and could help them to avoid the same pitfalls and establish a more credible service with good community integration from the start.

Child↗