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Biomedical subjects

P Lee

Publications and source records attributed to P Lee.

At least 73 records · Page 4Linked to original sources
PubMed2001

Laryngeal reinnervation with the hypoglossal nerve. I. Physiology, histochemistry, electromyography, and retrograde labeling in a canine model.

This study was performed to determine whether the hypoglossal nerve (cranial nerve XI [XII]) would serve as a useful donor for laryngeal reinnervation by anastomosis to the recurrent laryngeal nerve (RLN). Twenty hemilarynges in 10 dogs were studied prospectively after XII-RLN anastomosis (group A; n = 5), split XII-RLN anastomosis (group B; n = 3), XII-RLN anastomosis with a 2-cm interposition graft (group C; n = 2), no treatment (group D; n = 5), RLN section (group E; n = 2), or ansa cervicalis-RLN anastomosis (group F; n = 3). Spontaneous activity was observed monthly by infraglottic examination through permanent tracheostomies and was recorded by electromyography. Laryngeal adductory pressure and induced phonation were obtained by stimulating the RLN while passing a pressure transducer balloon or humidified air through the glottis. At sacrifice, the laryngeal muscles were stained for adenosine triphosphatase to determine the ratio of type I to type II fibers. Retrograde labeling of the brain stem was performed with horseradish peroxidase. Infraglottic examination at 6 months showed a full range of adductory motion in groups A and B during the swallow reflex, comparable with that in group D. Groups C and F showed good bulk and tone, but little spontaneous motion. Group E remained paralyzed. Stimulation of the transferred nerves caused more activity in groups A and B than in the other groups; groups C and F partially adducted at high levels. The laryngeal adductory pressure responses of groups A and B were similar to those of group D. The XII-reinnervated larynges were capable of producing normal induced phonation. Retrograde labeling of the RLN showed that the reinnervating axons originated only in the hypoglossal nucleus. Electromyography of the reinnervated adductor muscles confirmed spontaneous activity in the dogs (awake). Histochemical analysis confirmed slow-to-fast transformation of both the posterior and lateral cricoarytenoid muscles, indicating that significant reinnervation occurred. We conclude that the hypoglossal nerve functions well as a donor for adductory reinnervation of the larynx.

Actomyosin↗
PubMed2001

Is partnership in A&E feasible?

Partnership in care is frequently discussed within the discipline of children's nursing. There have been few definitions as to its meaning and therefore how it should be applied within the different specialties of children's nursing. This literature review identified a lack of research regarding partnership in care within the Accident and Emergency environment.

Child↗
PubMed2001

A new asthma severity index: a predictor of near-fatal asthma?

Bronchial hyperresponsiveness (BHR), measured as the provocative dose of inhaled histamine or methacholine required to produce a 20% fall in forced expiratory volume in one second (FEV1) (PD20), is widely used as one of the indices of asthma severity. Excessive bronchoconstriction, reflected by the maximal percentage fall in forced vital capacity (FVC) at PD20 (deltaFVC %) during BHR testing, is considered to be the most important pathophysiological determinant in fatal asthma. The present study hypothesized that an index which combines both the ease of airway narrowing and excessive bronchoconstriction, deltaFVC %/log(PD20), may be better in assessing asthma severity, especially in those at risk of near-fatal attacks. The dose-response curves of 46 asthmatics who underwent methacholine challenge testing were studied. Group 1 (n=14) patients had mild disease, Group 2 (n=21) had moderate disease and Group 3 (n=11) had severe disease, as classified according to the Global Initiative for Asthma. Nine patients had prior intubation for near-fatal asthma. deltaFVC %/log (PD20) was better than deltaFVC % and PD20 in categorizing patients into the three severity groups (p<0.0001), but more importantly, it was able to discriminate patients with previous intubation from those without (p=0.04). It also correlated better with FEV1 (% predicted), frequency of symptoms and inhaled steroid requirement than either index alone. It is concluded that the percentage fall in forced vital capacity/log of the provocative dose causing a 20% fall in forced expiratory volume in one second combines information on the ease and excessive degrees of airway narrowing in asthma. This new index may be better at assessing asthma severity and in discriminating those at risk of near-fatal attacks.

Adult↗
PubMed2001

Transmission of Mycobacterium tuberculosis to a funeral director during routine embalming.

Several studies have shown that funeral directors have an increased risk of tuberculosis (TB). Although there is indirect evidence of transmission of TB from cadavers to mortuary workers, there is only one recently documented case in the literature. We report here another case of occupationally acquired TB in a funeral director, which was confirmed by conventional epidemiology and genotyping. This case illustrates the risk of TB transmission to mortuary workers from routine embalming of deceased TB patients with active disease.

Adult↗
PubMed2001

Exposure of arctic field scientists to ultraviolet radiation evaluated using personal dosimeters.

During July 2000 we used an electronic personal dosimeter (X-2000) and a biological dosimeter (Deutsches Zentrum für Luft- und Raumfahrt: Biofilm) to characterize the UV radiation exposure of arctic field scientists involved in biological and geological fieldwork. These personnel were working at the Haughton impact structure on Devon Island (75 degrees N) in the Canadian High Arctic under a 24 h photoperiod. During a typical day of field activities under a clear sky, the total daily erythemally weighted exposure, as measured by electronic dosimetry, was up to 5.8 standard erythemal dose (SED). Overcast skies (typically 7-8 okta of stratus) reduced exposures by a mean of 54%. We estimate that during a month of field activity in July a typical field scientist at this latitude could potentially receive approximately 80 SED to the face. Because of body movements the upper body was exposed to a UV regimen that often changed on second-to-second time-scales as assessed by electronic dosimetry. Over a typical 10 min period on vehicle traverse, we found that erythemal exposure could vary to up to 87% of the mean exposure. Time-integrated exposures showed that the type of outdoor field activities in the treeless expanse of the polar desert had little effect on the exposure received. Although absolute exposure changed in accordance with the time of day, the exposure ratio (dose received over horizontal dose) did not vary much over the day. Under clear skies the mean exposure ratio was 0.35 +/- 0.12 for individual activities at different times of the day assessed using electronic dosimetry. Biological dosimetry showed that the occupation was important in determining daily exposures. In our study, scientists in the field received an approximately two-fold higher dose than individuals, such as medics and computer scientists, who spent the majority of their time in tents.

Adult↗
PubMed2001

Low back pain: prevalence and risk factors in an industrial setting.

OBJECTIVE: To examine various factors associated with low back pain (LBP) in an industrial setting. METHODS: A cross sectional study was carried out among 1,562 employees of a large utilities corporation in Ontario using a self-administered questionnaire. Abdominal muscle strength was measured using a modified sphygmomanometer. Statistical analysis was carried out with Student's t test, chi-square test, and logistic regression analysis. RESULTS: Among 1,302 male employees the lifetime and point prevalence of LBP were 60% and 11%, respectively. Low back pain was significantly more prevalent among married employees, with more physically demanding jobs, regular lifting, poor general health, and past major illness. Abdominal muscle weakness was associated with current LBP. The mean time lost from work due to LBP over 5 years was 17 days. Sedentary workers developing LBP were more likely to require hospital admission. CONCLUSION: This study confirms the high prevalence of LBP in industry and identifies several risk factors.

Abdominal Muscles↗
PubMed2001

Deep vein thrombosis in patients admitted for exacerbation of chronic obstructive pulmonary disease.

INTRODUCTION: There is a lack of data on the prevalence of deep vein thrombosis and pulmonary embolism in patients admitted to hospital for exacerbation of chronic obstructive pulmonary disease. Studies have found that most pulmonary embolism originate from deep vein thrombosis in the lower limbs, thus the prevalence of deep vein thrombosis may give an accurate reflection of the prevalence of pulmonary embolism. The aim of our study was to determine the prevalence of deep vein thrombosis in these patients, using duplex ultrasound of the lower limbs as the screening tool. METHODS: Thirty-three male patients admitted to the general ward for exacerbation of chronic obstructive pulmonary disease were screened for presence of deep vein thrombosis of the lower limbs using duplex ultrasound scan. RESULT: No patient in this study was found to have deep vein thrombosis of the lower limbs. CONCLUSIONS: The prevalence of deep vein thrombosis in local patients admitted for exacerbation of chronic obstructive pulmonary disease is likely to be low. We do not recommend the use of duplex ultrasound to screen for deep vein thrombosis in this group of patients.

Aged↗
PubMed2000

Strange magnetism and the anapole structure of the proton.

The violation of mirror symmetry in the weak force provides a powerful tool to study the internal structure of the proton. Experimental results have been obtained that address the role of strange quarks in generating nuclear magnetism. The measurement reported here provides an unambiguous constraint on strange quark contributions to the proton's magnetic moment through the electron-proton weak interaction. We also report evidence for the existence of a parity-violating electromagnetic effect known as the anapole moment of the proton. The proton's anapole moment is not yet well understood theoretically, but it could have important implications for precision weak interaction studies in atomic systems such as cesium.

Journal Article↗
PubMed2000

Molecular characterization of a case of atransferrinemia.

Hereditary atransferrinemia is a rare but instructive disorder that has previously been reported in only 8 patients in 6 families. It is characterized by microcytic anemia and by iron loading, and can be treated effectively by plasma infusions. We now report the first case known in the United States. We determined the sequences flanking the exons of the human transferrin gene and sequenced all of the exons and some of the flanking regions of the patient's DNA and that of her parents. The patient's DNA revealed a 10-base pair (bp) deletion, followed by a 9-bp insertion of a duplicated sequence. There was also a G-->C transversion at complementary DNA (cDNA) nt 1429, predicting that a proline was substituted for the alanine in amino acid position 477 (Ala 477 Pro). The latter mutation occurs at an evolutionarily highly conserved site; 704 control alleles were screened and this point mutation was not found. Each of the patient's transferrin genes contains one mutation, ie, the patient is a compound heterozygote for these mutations, because one was found in each of her parents. In addition to these mutations, which we regard to be causative in the patient's atransferrinemia, a silent polymorphism at cDNA 1572 G-->C was found in exon 13 as well as 2 previously unreported polymorphisms at IVS8 + 62 c-->t and IVS14-4 c-->a. The mutation in nt 1572 and that in intron 8 were common in the general population; the intron 14 mutation is rare.

Adult↗
PubMed2000

Functional interaction of human Cdc37 with the androgen receptor but not with the glucocorticoid receptor.

Cdc37 is a molecular chaperone closely associated with the folding of protein kinases. Results from studies using a yeast model system showed that it was also important for activation of the human androgen receptor (AR). Based on results from the yeast model system (Fliss, A. E., Fang, Y., Boschelli, F., and Caplan, A. J. (1997) Mol. Biol. Cell 8, 2501-2509), we initiated studies to address whether AR and Cdc37 interact with each other in animal cell systems. Our results show that Cdc37 binds to AR but not to glucocorticoid receptors (GR) synthesized in rabbit reticulocyte lysates. This binding occurs via the ligand-binding domain of the AR in a manner that is partially dependent on Hsp90 and the presence of hormone. Further studies using the yeast system showed that Cdc37 is not interchangeable with Hsp90, suggesting that it functions at a distinct step in the activation pathway. Expression of a dominant negative form of Cdc37 in animal cells down-regulates full-length AR but has very little effect on an AR truncation lacking the ligand-binding domain or full-length GR. These results reveal differences in the mechanisms by which AR and GR become active transcription factors and strengthen the notion that Cdc37 has a wider range of polypeptide clients than was realized previously.

Binding Sites↗
PubMed2000

Effects of season on fleece traits of Angora does in the US.

Twenty nonpregnant Angora does were used to determine seasonal effects on fleece traits, including fiber growth and follicle activity. Does grazed pastures and were supplemented with a 50% concentrate diet at a level near that required for BW maintenance. Clean fiber growth rate was greatest (p<0.05) among seasons in summer and lowest (p<0.05) in winter (1.13, 0.85, 0.98 and 1.20mg/cm(2) per day for autumn, winter, spring and summer, respectively); seasonal differences in fiber diameter were similar (34.9, 31.7, 33.7 and 36.5µm for autumn, winter, spring and summer, respectively). Fleece fiber medullation was greatest (p<0.05) in summer (0.48, 0.32, 0.40 and 0.76%), and medullated fiber diameter was greater in spring and summer than winter (69, 65, 73 and 71µm for autumn, winter, spring and summer, respectively). Primary follicle activity varied with season more than did activity of secondary follicles (primary: 74, 23, 79 and 99%; secondary: 97, 86, 94 and 99%; for autumn, winter, spring and summer, respectively). In summary, Angora goats in the US appear to exhibit seasonal follicle and fiber growth cycles, the knowledge of which may improve future nutritional management for efficient feed use in mohair production. The optimal time of shearing US Angoras for minimal contamination with medullated fibers may be just before spring and autumn equinoxes when it is likely that medullated fibers have been recently shed.

Journal Article↗
PubMed2000

Furosemide stimulates K transport in HCD57 erythroid cells.

We examined the influence of serum and furosemide on K movement and cell volume in HCD57 cells, a murine erythroleukemia cell line, which require erythropoietin (EPO) for survival. We found that maintenance of cell volume depends on the concentration of serum in the culture medium. In isotonic medium containing 20% serum, HCD57 cells maintain their steady-state volume. In contrast, the cells shrink progressively as medium serum content is reduced. In serum-free medium, raising external K to 75 mm prevents cell shrinkage and a further increase in K to 145 mm results in swelling, revealing a role for K permeability in the regulation of cell volume. Of particular interest has been a serendipitous finding with furosemide. Below an external K concentration of 2.1 +/- 0.3 mm in medium containing 2% serum, furosemide inhibits K uptake, probably stemming from its well known inhibitory action on KCl cotransport. However, above that K concentration, furosemide stimulates K uptake in a dose-dependent manner. Moreover, furosemide potentiates cell shrinkage induced by serum withdrawal. These findings suggest that the transport machinery mediating cellular shrinkage, once primed by serum depletion, becomes receptive to a second stimulus.

Animals↗
PubMed2000

A fragment of recombinant GABA(A) receptor alpha1 subunit forming rosette-like homo-oligomers.

The type A gamma-aminobutyric acid (GABA(A)) receptor plays a major role in inhibitory synaptic transmission in the central nervous system. A fragment consisting of residues Cys166 to Leu296 of the alpha1 subunit of the GABA(A) receptor was overexpressed in Escherichia coli and was found to have stable beta-rich structures. Here, results from laser scattering, gel electrophoresis and electron microscopy demonstrated that this recombinant protein formed rosette-like homo-oligomers, mainly pentamers in solution. Therefore, the fragment apparently provides a valuable model system for studying the pentameric holoreceptor assembly. Non-reducing sodium dodecyl sulfate polyacrylamide gel electrophoresis of the fragment showed that disulfide bonds formed between monomers contributed to the oligomerization of the fragment. The fact that this fragment alone could form pentamers in vitro strongly suggests that amino acid residues located within the Cys166-Leu296 region of the alpha1 subunit may contribute to the oligomerization of GABA(A) receptor in vivo.

Animals↗
PubMed2000

Views of academic dentists about careers in academic dentistry in the United Kingdom.

The aim of this paper is to report the views of academic dentists about careers in academic dentistry assessed by method of a postal questionnaire survey. The subjects of the survey were dentists in academic posts in the United Kingdom. The incentives in pursuing an academic career which respondents rated most highly were the opportunity to teach and the variety of work in an academic career. The greatest disincentives were competing pressures from service work, teaching and research, and the difficulty of getting research grants. Many would like to spend more time on research and less on service work and teaching. The length of time required for training, and the quality of training, was a concern, particularly for junior academics. Most respondents rated the enjoyment of their job highly but scored much lower on satisfaction with the time their job left for domestic and leisure activities. By contrast with academic medicine, in academic dentistry there is typically greater emphasis on teaching and less on research. In conclusion, the balance of activities in academic posts, particularly between service work, teaching and research, needs to be regularly reviewed. The development of a more structured training programme for junior academics, which does not disadvantage academic dentists when compared with their NHS colleagues, may be required.

Attitude of Health Personnel↗
PubMed2000

Parity violation in elastic electron-proton scattering and the Proton's strange magnetic form factor

We report a new measurement of the parity-violating asymmetry in elastic electron scattering from the proton at backward scattering angles. This asymmetry is sensitive to the strange magnetic form factor of the proton as well as electroweak axial radiative corrections. The new measurement of A = -4.92+/-0.61+/-0.73 ppm provides a significant constraint on these quantities. The implications for the strange magnetic form factor are discussed in the context of theoretical estimates for the axial corrections.

Journal Article↗