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Biomedical subjects

K Walker

Publications and source records attributed to K Walker.

At least 37 records · Page 2Linked to original sources
PubMed1998

Surgical treatment of carpal tunnel syndrome and trigger digits in children with mucopolysaccharide storage disorders.

The role of surgical intervention for carpal tunnel syndrome (CTS) and trigger digits in children with mucopolysaccharide storage disorders (MPSDs) has not been clearly defined, particularly as the treatment of the underlying disease has advanced to include bone marrow transplantation. This study reviews our experience in the treatment of CTS and trigger digits in 22 children with MPSDs who were evaluated for CTS by electromyographic (EMG)/nerve conduction velocity (NCV) testing. Seventeen children were diagnosed with CTS by EMG/NCV testing and were treated with bilateral open surgical release with or without flexor tenosynovectomy. The EMG/NCV testing revealed normal results in 5 patients who are subsequently being monitored. Forty-five digits in 8 children were diagnosed clinically with trigger digits. Nineteen digits were treated by annular pulley release alone. Twenty-six digits were treated by annular pulley release with partial flexor digitorum superficialis tendon resection. The average age at the time of hand surgery was 6.3 years, and at the time of follow-up, 9.6 years. Postoperative EMG/NCV testing in 7 children showed 1 with improvement and 6 with normalization. None of the patients undergoing carpal tunnel release went on to develop thenar atrophy or absent sensibility, as has been reported in untreated cases. Patients were evaluated for triggering digits both by preoperative tendon palpation and by intraoperative flexor tendon excursion at the time of open carpal tunnel release. All patients undergoing trigger release had improved active digital flexion seen at the final follow-up visit. Because of the very high incidence of CTS and trigger digits in this population, the authors currently recommend routine screening of EMG/NCV for all children with MPSDs. Early surgical intervention for nerve compression and stenosing flexor tenosynovitis can maximize hand function in these children.

Age Factors↗
PubMed1998

A 5 year strategic plan of action.

Exciting innovations for the new millennium as the NSW College of Nursing becomes more relevant, dynamic and accessible to its members.

Forecasting↗
PubMed1997

Structure of the monophosphoryl lipid A moiety obtained from the lipopolysaccharide of Chlamydia trachomatis.

Monophosphoryl lipid A was prepared from the lipopolysaccharide of Chlamydia trachomatis, converted to the methyl ester, and fractionated by reverse-phase high-performance liquid chromatography. The peak fractions were collected and analyzed by mass spectrometry. Matrix-assisted laser desorption/ionization and liquid secondary ion mass spectrometry of the first of two major high-performance liquid chromatographic fractions showed multiple quasi-molecular ions of MNa+ at m/z 1780, 1794, 1808, 1822, and 1836. The positive-ion liquid secondary ion mass spectrometry spectrum also showed a minor series of peaks at m/z 1916, 1930, 1944, 1958, and 1971, consistent with the formation of matrix adducts with 3-nitrobenzyl alcohol. Oxonium ions representing the distal subunit were observed at m/z 1057, 1071, 1085, 1099, and 1113. The second fraction was similarly analyzed and found to contain structural homologs of the first fraction. Based on this study, the major lipid A component of chlamydial lipopolysaccharide is a glucosamine disaccharide that contains five fatty acids and a phosphate in the distal segment. Three fatty acyl groups are in the distal segment, and two are in the reducing end segment. The acyloxyacyl group is located in the distal segment in amide linkage. Two structural series, differing by 14 atomic mass units in the reducing subunit, were observed. Chlamydial lipid A is complex and consists of at least 20 homologous structural components. The relatively low potency of Chlamydia trachomatis lipopolysaccharide in activating lipopolysaccharide-responsive cells might be related to the unusual fatty acid composition of the lipid A moiety.

Chlamydia trachomatis↗
PubMed1997

Supramolecular Materials: Self-Organized Nanostructures

Miniaturized triblock copolymers have been found to self-assemble into nanostructures that are highly regular in size and shape. Mushroom-shaped supramolecular structures of about 200 kilodaltons form by crystallization of the chemically identical blocks and self-organize into films containing 100 or more layers stacked in a polar arrangement. The polar supramolecular material exhibits spontaneous second-harmonic generation from infrared to green photons and has an adhesive tape-like character with nonadhesive-hydrophobic and hydrophilic-sticky opposite surfaces. The films also have reasonable shear strength and adhere tenaciously to glass surfaces on one side only. The regular and finite size of the supramolecular units is believed to be mediated by repulsive forces among some of the segments in the triblock molecules. A large diversity of multifunctional materials could be formed from regular supramolecular units weighing hundreds of kilodaltons.

Journal Article↗
PubMed1997

Clinical trial of moxidectin oral gel in horses.

A clinical trial carried out over 98 days was done to evaluate treatment of horses with moxidectin gel for efficacy as measured by (1) reduction in the production of parasite ova post treatment, (2) a comparison of the posttreatment parasite egg count suppression of moxidectin to ivermectin, and (3) assessment of the field safety, animal acceptance of the moxidectin formulation, and the utility of the moxidectin delivery device. One hundred and fifty Standardbred horses with naturally acquired parasite infections were used in the study. Moxidectin had more prolonged and greater suppressive influence than did ivermectin on reappearance and magnitude of strongyle egg counts post treatment. Differences were not observed between the capability of ivermectin or moxidectin to reduce and suppress low Parascaris equorum egg counts. Adverse reactions to treatments were not observed, and the utility of the moxidectin delivery syringe and animal acceptance of moxidectin treatment were satisfactory.

Administration, Oral↗
PubMed1997

Catecholamine modulatory effects of nepicastat (RS-25560-197), a novel, potent and selective inhibitor of dopamine-beta-hydroxylase.

1. Inhibitory modulation of sympathetic nerve function may have a favourable impact on the progression of congestive heart failure. Nepicastat is a novel inhibitor of dopamine-beta-hydroxylase, the enzyme which catalyses the conversion of dopamine to noradrenaline in sympathetic nerves. The in vitro pharmacology and in vivo catecholamine modulatory effects of nepicastat were investigated in the present study. 2. Nepicastat produced concentration-dependent inhibition of bovine (IC50 = 8.5 +/- 0.8 nM) and human (IC50 = 9.0 +/- 0.8 nM) dopamine-beta-hydroxylase. The corresponding R-enantiomer (RS-25560-198) was approximately 2-3 fold less potent than nepicastat. Nepicastat had negligible affinity (> 10 microM) for twelve other enzymes and thirteen neurotransmitter receptors. 3. Administration of nepicastat to spontaneously hypertensive rats (SHRs) (three consecutive doses of either 3, 10, 30 or 100 mg kg-1, p.o.; 12 h apart) or beagle dogs (0.05, 0.5, 1.5 or 5 mg kg-1, p.o.; b.i.d., for 5 days) produced dose-dependent decreases in noradrenaline content, increases in dopamine content and increases in dopamine/noradrenaline ratio in the artery (mesenteric or renal), left ventricle and cerebral cortex. At the highest dose studied, the decreases in tissue noadrenaline were 47%, 35% and 42% (in SHRs) and 88%, 91% and 96% (in dogs) in the artery, left ventricle and cerebral cortex, respectively. When tested at 30 mg kg-1, p.o., in SHRs, nepicastat produced significantly greater changes in noradrenaline and dopamine content, as compared to the R-enantiomer (RS-25560-198), in the mesenteric artery and left ventricle. 4. Administration of nepicastat (2 mg kg-1, b.i.d, p.o.) to beagle dogs for 15 days produced significant decreases in plasma concentrations of noradrenaline and increases in plasma concentrations of dopamine and dopamine/noradrenaline ratio. The peak reduction (52%) in plasma concentration of noradrenaline and the peak increase (646%) in plasma concentration of dopamine were observed on day-6 and day-7 of dosing, respectively. 5. The findings of this study suggest that nepicastat is a potent, selective and orally active inhibitor of dopamine-beta-hydroxylase which produces gradual modulation of the sympathetic nervous system by inhibiting the biosynthesis of noradrenaline. This drug may, therefore, be of value in the treatment of cardiovascular disorders associated with over-activation of the sympathetic nervous system, such as congestive heart failure.

Animals↗
PubMed1997

Cutting edges: deconstructive inquiry and the mission of the border ethnographer.

Research is an activity nursing 'cannot not want'. Such an imperative compels me to sketch out some theoretical borders of a hybrid postmodern methodological framework that I have called 'border' ethnography. It is a methodology suspended between a still authoritative modernity and an as yet only partially legitimate postmodernity. At one level this position is somewhat uncomfortably in a post-methodological terrain. The text that issues from such a tension-laden research space is, I argue, intensely autobiographical, inescapably ethnographic and inherently deconstructive. Ethno(autobio) graphy is a method 'on the run'; it destabilizes while it authorizes, it represents while it misrepresents, and it threatens to disintegrate as it comes into view. But, most importantly, it is the creature of a praxis-oriented endeavour not only to better understand a culture, but to actively intervene in its (re) production.

Anthropology, Cultural↗
PubMed1997

Fatigue, depression, and quality of life in HIV-positive men.

1. Fatigue is a real symptom of HIV infection, and up to two thirds of clients with HIV report symptoms of depression. 2. Depression and fatigue, besides being closely related in HIV cases, have an adverse effect on quality of life. 3. Treating depression and underlying causes of fatigue will improve the quality of life for patients with HIV, who now have an extended life span.

Activities of Daily Living↗
PubMed1997

Depression.

Often unrecognised and untreated, clinical depression exacts a high toll in terms of social, emotional and economic damage. Nurses are well placed to observe the early symptoms of depression and ensure that appropriate treatment is obtained.

Depression↗
PubMed1997

Nucleic acid amplification for rapid detection of Rhodococcus equi in equine blood and tracheal wash fluids.

OBJECTIVE: To evaluate the ability of nucleic acid amplification techniques to detect Rhodococcus equi in equine buffy coat, blood, and tracheal wash fluid and to differentiate between virulent and avirulent strains of the bacteria. SAMPLE POPULATION: Blood anticoagulated with EDTA and tracheal wash fluid from healthy horses. PROCEDURE: Logarithmic dilutions of virulent and avirulent strains of R equi were added to equine buffy coat and tracheal wash fluid samples. The DNA was extracted and amplified by polymerase chain reaction (PCR), using primers specific for the 16S ribosomal subunit gene and the virulence plasmid of R equi. RESULTS: PCR with 16S ribosomal subunit primers amplified a 441-bp segment of DNA from virulent and avirulent strains of R equi, but not from samples containing other species of bacteria. The virulence plasmid primers amplified an 875-bp segment of DNA from virulent strains of R equi, but not from avirulent R equi, or from other species of bacteria. Virulent strains of R equi could be identified by PCR and differentiated from avirulent strains within 12 to 24 hours after sample collection, with as few as 10 to 100 organisms present. CONCLUSIONS: PCR can be used to rapidly and accurately identify R equi in equine blood and tracheal wash fluid samples and can differentiate between virulent and avirulent strains of the organism. CLINICAL RELEVANCE: Because PCR can confirm a diagnosis of R equi infection in horses more rapidly and specifically than use of standard culture techniques, extrapolation of this assay to soil and fecal samples could be useful in epidemiologic studies and studies of environmental disinfection or decontamination.

Actinomycetales Infections↗
PubMed1996

Peptide, disulfide, and glycosylation mapping of recombinant human thrombopoietin from ser1 to Arg246.

Thrombopoietin (TPO) is a hematopoietic factor involved in the regulation of megakaryocytopoiesis. Full length recombinant human TPO (332 residues) has been expressed in BHK cells and purified to homogeneity using conventional means. Peptide, disulfide, and glycosylation mapping of human TPO from residues 1 to 246 has been carried out using liquid chromatography-electrospray mass spectrometry (LC-ESMS). A modification of the ramped orifice method of Carr and co-workers [Carr et al. (1993) Protein Sci. 2, 183-196] is employed, providing additional information for assignment of the LC-ESMS chromatograms. With the modification, b- and y-series peptide ions are produced via front-end CID which confirms the mass-based assignments. The results of our analysis of TPO indicate that the amino acid sequence of TPO 1-246 is as expected from the transfected cDNA with complete cleavage of the signal peptide. Two unique disulfides are formed between the four cysteines in the cytokine domain of TPO: Cys7-Cys151 and Cys29-Cys85. The glycosylation map indicates the position, occupancy, and structures of the N- and O-glycans in TPO 1-246. In addition, site specific structural characterization of the PNGase F-liberated N-glycans has been performed following purification by high-pH anionic exchange chromatography with pulsed amperometric detection (HPAEC-PAD); the results corroborate the LC-ESMS data. The N-glycans are of the complex type with the core-fucosylated disialylated biantennary and trisialylated triantennary structures predominating. The O-glycans are of the mucin type with the monosialylated and disialylated GalGalNAc-S/T structures predominating. Furthermore, we propose that the C-terminal domain of TPO be further divided into two domains on the basis of sequence homology among the cloned sequences and glycosylation/structural features: an N-glycan domain (154-246) and an O-glycan domain (247-332).

Amino Acid Sequence↗
PubMed1996

Development of hyperthermia and hyperalgesia following intracerebroventricular administration of endotoxin in the rat: effect of kinin B1 and B2 receptor antagonists.

The present study investigated the development of hyperthermia and thermal and mechanical hyperalgesia following i.c.v. injections of E. coli lipopolysaccharide (LPS) in rats. LPS increased core temperature and this was prevented by i.c.v. administration of HOE 140, a kinin B2 receptor antagonist or by indomethacin i.c.v. or i.v. B1 receptor antagonists had no effect. LPS induced thermal and mechanical hyperalgesia which was reversed by i.c.v. HOE 140 and indomethacin i.c.v. and i.v., but not by B1 receptor antagonists. These results indicate that injections of endotoxin to the CNS induces hyperthermia and hyperalgesia and that kinins, acting on centrally located B2 receptors, and prostanoids are involved.

Animals↗
PubMed1996

Development of hyperthermia following intracerebroventricular administration of endotoxin in the rat: effect of kinin B1 and B2 receptor antagonists.

1. E. coli lipopolysaccharide (LPS) produced a dose-dependent (dose range: 0.02-150 micrograms) increase in rat core temperature that was maximal 6 h after intracerebroventricular (i.c.v.) administration. LPS (200 ng) increased core temperature by 1.0 +/- 0.2 degrees C, 6 h following administration, as compared to vehicle-treated controls (-0.2 +/- 0.2 degrees C). 2. LPS-induced (200 ng) hyperthermia was prevented by co-administration of the bradykinin (BK) B2 receptor antagonist, Hoe 140 (10 and 30 pmol, i.c.v.) or by indomethacin (10 nmol, i.c.v.). 3. Systemic administration of Hoe 140 at doses up to 1 mumol kg-1, s.c., did not attenuate LPS-induced (200 ng, i.c.v.) hyperthermia. However, LPS hyperthermia was significantly reduced by systemic administration of indomethacin (1 mumol kg-1, i.v.). 4. Co-administration of the selective B1 receptor antagonists, [des-Arg9, Leu8]BK (0.1 - 1 nmol, i.c.v.) or [des-Arg10] Hoe 140 (0.1 - 1 nmol, i.c.v.), did not prevent LPS-induced hyperthermia. 5. It is concluded that the development of hyperthermia following central administration of endotoxin requires activation of central, but not peripheral bradykinin B2 receptors. The formation of kinins within the CNS may be an important initial component of CNS inflammation following infection.

Animals↗
PubMed1996

Health check-ups in general practice: a patient perspective.

One of the strategies identified by the NHS to achieve improvements in the health status of the Scottish population is to implement health promotion programmes through the general medical practitioner service. Grampian Local Health Council undertook a survey of Grampian residents to identify factors which might encourage greater public participation in such programmes. The results which are analysed and discussed in this paper show that factors identified by the public include: a preference for doctors to carry out health checks; the need for public education on the roles of different health professionals; the need for information on health checks and their benefits to be supplied in advance; a choice of appointment times and the offer of a follow-up appointment to discuss test results. These results are of interest to health professionals as they are likely to contribute to higher levels of patient involvement in health promotion programmes.

Adult↗