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Biomedical subjects

P Lee

Publications and source records attributed to P Lee.

At least 127 records · Page 7Linked to original sources
PubMed1999

A comparison of ultrasonic beams for thermal treatment of ocular tumors.

OBJECTIVE: This study examined the relative merits of different ultrasonic beams and exposure modalities for treating ocular melanomas. METHODS: Simulations were conducted to evaluate temperature patterns and lesion shapes induced by intense-ultrasound treatment of ocular tumors. In-vitro insonification experiments were conducted in bovine lenses. RESULTS: Simulated hyperthermia exposures did not effectively treat tumor margins because of thermal conduction into nearby fluid-like media. Standard high-intensity focused beams produced narrow lesions during 2-s exposures. A high-intensity, multi-lobed beam, produced by a transducer with strip electrodes, generated asymmetric lesions with a single large dimension; this lesion shape could expedite the production of lesion matrices within large tumors. In-vitro cataract shapes were consistent with simulation results for focused high-intensity beams. CONCLUSIONS: Thermal conduction and perfusion can cause underheating of tumor margins during hyperthermia unless special beam designs are used. The strip-electrode transducer configuration promises to expedite treatment of extended tumor volumes.

Animals↗
PubMed1999

Partnership in care: a critical exploration of how this may be applied to children attending the Accident and Emergency department.

Partnership in care is an emerging theme within children's nursing. There has, however, been much debate in the literature about what partnership in care is, but little consensus has been achieved as to its meaning. Partnership in care has been examined from the perspectives of both the parents and the nurses, although principally the work to date has focused on children's wards. More recently the work on partnership in care has examined how this may work in the children's out-patient department and also within community children's nursing. Little appears to have been written about partnership in care in the Accident and Emergency (A&E) environment, and some possible reasons for this have been postulated. Three aspects of partnership in care: negotiation and equality of care, parents as equal partners, and responsibility for care being shifted have all been examined and applied to the A&E setting. Suggestions for research are offered throughout the discussion. Finally, the role of the registered children's nurse is examined in view of the analysis.

Adult↗
PubMed1999

Nasendoscopically-assisted placement of a nasogastric feeding tube.

Nasogastric tube placement is desirable for the short-term administration of calories when oral feeding is not possible. Enteral nutrition is superior to parenteral nutrition. In some patients this method of feeding is impossible because of repeated failure of nasogastric tube placement, necessitating either general anaesthesia for enteral access, or total parenteral nutrition. We describe a new method for nasogastric tube placement aided by a fibre-optic nasendoscope which has resulted in the successful placement of over 20 nasogastric tubes in our unit and the avoidance of more invasive methods of establishing nutrition with their associated complications.

Anesthesia, Local↗
PubMed1999

Screening for undetected mental disorders in high utilizers of primary care services.

OBJECTIVE: To define the prevalence and detection rates of mental disorders among high utilizers as compared with typical utilizers, and to examine the effect of case-mix adjustment on these parameters. DESIGN: Cross-sectional study. SETTING: General internal medicine outpatient clinic associated with an urban, academic medical center. PATIENTS: From patients attending a general medicine clinic, 304 were selected randomly in three utilization groups, defined by number of clinic visits: (1) high utilizers; (2) case-mix adjusted high utilizers; and (3) typical utilizers (control patients). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The presence of any mental disorder was ascertained by the PRIME-MD screening instrument. Chart review on all patients was performed to ascertain mental disorders detected by primary care physicians. The prevalence of mood disorders was markedly higher in high utilizers (29%) than in adjusted high utilizers (15%) or controls (10%) (p <.001). Anxiety disorders were slightly, but not statistically, more prevalent in the group adjusted for case mix (16%) than in other high utilizers (12%) or controls (9%). Alcoholism was significantly more prevalent in controls (12%) than in adjusted (6%) or other high utilizers (3%) (p <.03). The discrepancy in detection rates between PRIME-MD and chart review for any mental disorder was less for high utilizers (37% vs 31%) as compared with adjusted high utilizers (31% vs 11%) or controls (24% vs 8%). CONCLUSIONS: Mood disorders are associated with a high overall burden of illness, while anxiety disorders are more predominant among outliers after case-mix adjustment. Detection rates differ substantially by utilization pattern. Screening efforts can be more appropriately targeted with knowledge of these patterns.

Adult↗
PubMed1999

Gender difference in management of epilepsy-what women are hearing.

This study reports the results of a questionnaire survey of female members of the British Epilepsy Association (BEA). The women were asked about their concerns about their epilepsy with respect to being female, and, in particular, asked about the information they had been given on important topics such as contraception and pregnancy. A questionnaire was sent to 6000 BEA female members of whom 1855 (31%) replied. Forty-six percent of the women (mainly aged between 26 and 45) stated that they currently used some form of contraception. The most frequently used method was the condom (34%). Twenty-two percent of the women using contraception were taking the oral contraceptive pill whilst a further 4% were using a hormonal contraceptive injection. Fifty-one percent of the women aged between 16 and 55 claimed not to have received any advice about possible interactions between contraception and antiepileptic drug therapy. With regards to pregnancy, 34% claimed they had not received any advice and 25% had not discussed pregnancy with anyone. The women planning to have children over the subsequent 2 years received the greatest amount of advice about epilepsy and pregnancy, although 20% still claimed not to have received any information. Thirty-four percent of the women in the study stated that they were either menopausal or post-menopausal. Twenty-nine percent of women who had taken hormone replacement therapy in the past reported an increase in seizure frequency compared with 18% amongst current users. This survey has shown that women with epilepsy want, and need, more information and counselling about issues relating to contraception, pregnancy and the menopause.

Adolescent↗
PubMed1999

Women with epilepsy: their views about their treatment and care.

This study reports the results of a questionnaire survey of female members of the British Epilepsy Association. The women were asked about their epilepsy and its management. A questionnaire was sent to 6000 BEA women members of whom 1855 (31%) replied. The majority of women (89%) stated they currently take older antiepileptic medications, either as monotherapy or in combination with others. Newer antiepileptic drugs were prescribed to 30% of women. The most frequently mentioned antiepileptic drug side-effects were tiredness and forgetfulness. Seventy percent of the sample considered that the lack of energy had at least a moderate impact on their life. Thirty-eight percent of women would have liked better seizure control whilst 32% agreed that they would prefer to change to a medication with fewer side-effects. However, 49% were reluctant to change their medication. Fifty-nine percent stated that they see their hospital specialist regularly whilst half the sample (49%) saw their GP regularly. Hospital specialists on the whole, played a more active role in the management of epilepsy than GPs. Many women (68%) felt that their GP's main task appeared to be to write prescriptions and 40% felt that they knew more about their epilepsy than their GP. However, the women generally perceived that their GP or hospital specialists were sympathetic to their condition and their concerns.

Adolescent↗
PubMed1999

Complete genomic structure and mutational spectrum of PHKA2 in patients with x-linked liver glycogenosis type I and II.

X-linked liver glycogenosis (XLG) is probably the most frequent glycogen-storage disease. XLG can be divided into two subtypes: XLG I, with a deficiency in phosphorylase kinase (PHK) activity in peripheral blood cells and liver; and XLG II, with normal in vitro PHK activity in peripheral blood cells and with variable activity in liver. Both types of XLG are caused by mutations in the same gene, PHKA2, that encodes the regulatory alpha subunit of PHK. To facilitate mutation analysis in PHKA2, we determined its genomic structure. The gene consists of 33 exons, spanning >/=65 kb. By SSCP analysis of the different PHKA2 exons, we identified five new XLG I mutations, one new XLG II mutation, and one mutation present in both a patient with XLG I and a patient with XLG II, bringing the total to 19 XLG I and 12 XLG II mutations. Most XLG I mutations probably lead to truncation or disruption of the PHKA2 protein. In contrast, all XLG II mutations are missense mutations or small in-frame deletions and insertions. These results suggest that the biochemical differences between XLG I and XLG II might be due to the different nature of the disease-causing mutations in PHKA2. XLG I mutations may lead to absence of the alpha subunit, which causes an unstable PHK holoenzyme and deficient enzyme activity, whereas XLG II mutations may lead to in vivo deregulation of PHK, which might be difficult to demonstrate in vitro.

Base Sequence↗
PubMed1999

Neuronal nitric oxide synthase expression in developing and adult human CNS.

Neuronal nitric oxide synthase (nNOS) is constitutively expressed by subpopulations of neurons in the CNS and is involved in neurotransmission, learning and memory, and neuronal injury. While the distribution of nNOS neurons has been characterized in the rodent CNS, the expression in human brain has not been well documented. We determined the expression of nNOS in second trimester human fetal and adult brain. In second trimester fetal brain, the nNOS neurons are concentrated in the developing cerebral cortex at the subplate zone and in layer VI, the striatum, and in certain brainstem nuclei. The nNOS neurons are sparsely distributed in the hippocampus, and virtually absent in the cerebellar cortex. The nNOS neurons in the subplate zone extend their processes radially, suggesting a developmental role, perhaps in guidance. The number and distribution of NADPH diaphorase-positive neurons corresponds to that of the nNOS neurons. While the distribution of nNOS neurons in the adult brain is similar to that found in fetal brain, the overall density is lower in the adult. The highest density of nNOS neurons is found in the striatum followed by the neocortex. A region-specific role for nNOS neurons in human brain and a potential developmental role for nNOS in the cerebral cortex are suggested by these data.

Adult↗
PubMed1999

Effects of stimulant medication on the lateralisation of line bisection judgements of children with attention deficit hyperactivity disorder.

OBJECTIVES: Deficits in the maintenance of attention may underlie problems in attention deficit hyperactivity disorder (ADHD). Children with ADHD also show asymmetric attention deficits in traditional lateralisation and visuospatial orienting tasks, suggesting right hemispheric (and left hemispace) attentional disturbance. This study aimed to examine the lateralisation of selective attention in ADHD; specifically, the effect of a moving, random dot background, and stimulant medication in the line bisection task. METHODS: The performance of children with ADHD, on and off methylphenidate, was examined using a computerised horizontal line bisection task with moving and blank backgrounds. Twenty children with a DSM-IV diagnosis of ADHD participated with 20 controls, individually matched for age, sex, grade at school, and IQ. Twelve of the 20 children with ADHD were on stimulant medication at the time of testing. Horizontal lines of varying length were presented in the centre of a computer screen, with either a blank background, or a moving, random dot field. The random dots moved either leftward or rightward across the screen at either 40 mm/s or 80 mm/s. RESULTS: The children with ADHD off medication bisected lines significantly further to the right compared with controls, who showed a small leftward error. Methylphenidate normalised the performance of the children with ADHD for the task with the moving dots. CONCLUSIONS: These results support previous evidence for a right hemispheric hypoarousal theory of attentional dysfunction, and are consistent with the emerging picture of a lateralised dysfunction of frontostriatal circuitry in ADHD.

Analysis of Variance↗
PubMed1999

Muscle substrate utilization and lactate production.

Biopsies (biceps) were examined in 8 bodybuilders across a typical arm-curl training session (80% 1-RM). [PCr] and [glycogen] decreased 62 and 12% after 1 set (n = 4), and 50 and 24% after 3 sets (n = 4). [Lactate] was 91 and 118 mmol &times kg-1, respectively, after 1 and 3 sets. Fatigue was probably partially caused by decreased [PCr] and increased [H+] (first set) and by decreased [H+] in subsequent sets.

Adenosine Triphosphate↗
PubMed1999

Local excitatory circuits in the intermediate gray layer of the superior colliculus.

We have used photostimulation and whole cell patch-clamp recording techniques to examine local synaptic interactions in slices from the superior colliculus of the tree shrew. Uncaging glutamate 10-75 microm from the somata of neurons in the intermediate gray layer elicited a long-lasting inward current, due to direct activation of glutamate receptors on these neurons, and brief inward currents caused by activation of presynaptic neurons. The synaptic responses occurred as individual currents or as clusters that lasted up to several hundred milliseconds. Excitatory synaptic responses, which reversed at membrane potentials near 0 mV, could be evoked by uncaging glutamate anywhere within 75 microm of an intermediate layer neuron. Our results indicate the presence of extensive local excitatory circuits in the intermediate layer of the superior colliculus and support the hypothesis that such intrinsic circuitry contributes to the development of presaccadic command bursts.

Animals↗
PubMed1999

Hypoglossal nerve transfer for laryngeal reinnervation: a preliminary study.

The hypoglossal nerve is a logical donor nerve for hemilaryngeal reinnervation because 1) its activity coincides with normal laryngeal adduction during speech and deglutition; 2) it is a large nerve with many axons; and 3) donor site morbidity is low. This method of laryngeal reinnervation has not been previously reported. Previous studies using the ansa cervicalis for reinnervation have failed to show spontaneous activity. Hypoglossal-to-recurrent laryngeal nerve anastomosis was performed on a series of 5 dogs. The vocal folds were viewed monthly, with the animals awake, by infraglottic examination through a permanent tracheostomy. One dog failed due to technical error. The remaining 4 dogs began to exhibit spontaneous vocal fold adduction within 2 to 4 months. Vocal fold motion was synchronous with spontaneous tongue motion. Complete glottic closure was seen during swallowing at 3 to 5 months. Intraglottic pressure measurements following reinnervation were normal. Hypoglossal nerve transfer appears to be capable of providing functional adduction to the paralyzed hemilarynx. The potential advantages and disadvantages of this new technique are discussed.

Anastomosis, Surgical↗
PubMed1999

Laryngeal chemodenervation: effects of injection site, dose, and volume.

A canine model was used to measure changes in laryngeal adductory pressure (LAP) following injections of vecuronium bromide, a short-acting neuromuscular blocking agent. At a constant volume, LAP was inversely related to the dose (and concentration) of vecuronium injected. At a constant dose (0.05 mg), LAP did not vary significantly over a wide range of injection volumes, from 0.05 to 0.50 mL. At a constant dose and volume, the site of injection was varied among the anterior, middle, and posterior vocal fold, the interarytenoid region, and the anterior contralateral vocal fold. Reduction in LAP was greatest (p<.05) for the posterior vocal fold injection site (78% reduction); less reduction was seen for the middle (54%) and anterior (52%) vocal fold and interarytenoid (43%) injection sites. These results have implications for laryngeal botulinum toxin injections, which are discussed.

Animals↗
PubMed1999

Lack of effect of erythromycin and ketoconazole on the pharmacokinetics and pharmacodynamics of steady-state intranasal levocabastine.

The single-dose effects of the cytochrome P-450 inhibitors erythromycin and ketoconazole on the steady-state pharmacokinetics and electrocardiographic repolarization pharmacodynamics of intranasal levocabastine, a potent and selective H1-receptor antagonist, were evaluated in healthy young male subjects. Two randomized, open-label, placebo-controlled, two-way crossover studies were performed. Levocabastine nasal spray was administered as two sprays per nostril (0.05 mg/spray) twice daily (for a total daily dose of 0.4 mg) for 6 days. On Day 7, a single dose of 0.2 mg was administered followed immediately by a single dose of either oral placebo, erythromycin 333 mg, or ketoconazole 200 mg. In all treatment groups, levocabastine was rapidly absorbed, with peak plasma concentrations reached at approximately 3 hours in the erythromycin study and 2.8 hours in the ketoconazole study. The mean terminal half-life was approximately 45 and 44 hours, respectively. In both studies, mean steady-state plasma concentrations and pharmacokinetics of levocabastine following the single doses of erythromycin or ketoconazole were not significantly different from corresponding values seen with the concomitant administration of the placebo. No clinically significant mean changes from baseline in QT or QTc (QT corrected for heart rate) intervals occurred in any of the treatment groups, and none of the subjects in either study experienced abnormally prolonged QTc intervals. Intranasal levocabastine was well tolerated, with no difference in the incidence of adverse events between treatment groups in either study; adverse events were generally mild in severity. Since levocabastine undergoes only minimal hepatic metabolism and is not a substrate for or an inhibitor of cytochrome P-450, the likelihood of systemic drug interactions with drugs affecting the cytochrome P-450 system is minimal.

Administration, Intranasal↗