Biomedical subjects

D Smith

Publications and source records attributed to D Smith.

At least 55 records · Page 3Linked to original sources

PubMed2005

Oral bisphosphonates improve Bone Mineral Density in adults with cystic fibrosis.

In adults with Cystic Fibrosis (CF) we sought to establish the effect of oral bisphosphonate therapy. Bone densitometry measured by dual energy X-ray absorptiometry (DXA), and clinical patient data, were reviewed retrospectively. Eighty-one patients (median age 27 years) had baseline and follow-up DXA, with an interval of 19.2 +/- 7.1 months. Thirty-six patients were treated with bisphosphonates (alendronate=23 and risedronate=13). Median follow-up Bone Mineral Density in the bisphosphonate group was 3.7% greater at the lumbar spine (95%CI 1.9 to 5.7%, P<0.0005) and 2.4% greater at the femur (95%CI 0.8 to 3.9%, P<0.005) than the group not treated with bisphosphonates. Oral bisphosphonate therapy had a beneficial effect on BMD in adults with CF.

Administration, Oral↗

PubMed2004

A determination of the Cabibbo-Kobayashi-Maskawa parameter |V us| using KL decays.

We present a determination of the Cabibbo-Kobayashi-Maskawa parameter |V(us)| based on new measurements of the six largest K(L) branching fractions and semileptonic form factors by the KTeV (E832) experiment at Fermilab. We find |V(us)|=0.2252+/-0.0008(KTeV)+/-0.0021(ext), where the errors are from KTeV measurements and from external sources. We also use the measured branching fractions to determine the CP violation parameter |eta(+-)|=(2.228+/-0.005(KTeV)+/-0.009(ext))x10(-3).

Journal Article↗

PubMed2004

The effect of modafinil on counter-regulatory and cognitive responses to hypoglycaemia.

AIMS/HYPOTHESIS: Our hypothesis is that reducing release of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) with modafinil will enhance symptomatic and hormonal responses to hypoglycaemia. METHODS: Nine healthy men received, in random order, two 100-mg doses of modafinil or placebo, followed by an insulin clamp in which plasma glucose was either reduced stepwise to 2.4 mmol/l or was sustained at euglycaemia (four studies). Catecholamines, symptom scores and cognitive function were measured. RESULTS: Modafinil had no effect on the measured parameters during euglycaemia. During hypoglycaemia, autonomic symptom scores were significantly higher with modafinil (increase at lowest plasma glucose concentration 271.3+/-118.9 vs 211.2+/-80.4/40 min, p=0.019), and the heart rate response was increased (12,928+/-184 vs 6773+/-148 bpm/140 min, p=0.016). Deterioration in performance of two cognitive tasks was reduced: Stroop colour-word test (613+/-204 vs 2375+/-161/65 min, p=0.009) and accuracy of a simple reaction task (11.3+/-1.8 vs 9.4+/-3.7, p=0.039). CONCLUSIONS/INTERPRETATION: We conclude that modafinil improves adrenergic sensitivity and some aspects of cognitive function at hypoglycaemia, possibly by reducing neuronal central GABA concentrations.

Adult↗

PubMed2004

Downward resetting of the osmotic threshold for thirst in patients with SIADH.

The syndrome of inappropriate antidiuretic hormone (SIADH) is characterized by euvolemic hyponatremia. Patients with SIADH continue to drink normal amounts of fluid, despite plasma osmolalities well below the physiological osmotic threshold for onset of thirst. The regulation of thirst has not been previously studied in SIADH. We studied the characteristics of osmotically stimulated thirst and arginine vasopressin (AVP) secretion in eight subjects with SIADH and eight healthy controls and the nonosmotic suppression of thirst and AVP during drinking in the same subjects. Subjects underwent a 2-h infusion of hypertonic (855 mmol/l) NaCl solution, followed by 30 min of free access to water. Thirst rose significantly in both SIADH (1.5 +/- 0.6 to 8.0 +/- 1.2 cm, P < 0.0001) and controls (1.8 +/- 0.8 to 8.4 +/- 1.5 cm, P < 0.0001), but the osmotic threshold for thirst was lower in SIADH (264 +/- 5.5 vs. 285.9 +/- 2.8 mosmol/kgH(2)O, P < 0.0001). SIADH subjects drank volumes of water similar to controls after cessation of the infusion (948.8 +/- 207.6 vs. 1,091 +/- 184 ml, P = 0.23). The act of drinking suppressed thirst in both SIADH and controls but did not suppress plasma AVP concentrations in SIADH compared with controls (P = 0.007). We conclude that there is downward resetting of the osmotic threshold for thirst in SIADH but that thirst responds to osmotic stimulation and is suppressed by drinking around the lowered set point. In addition, we demonstrated that drinking does not completely suppress plasma AVP in SIADH.

Adult↗

PubMed2004

Nondemolition measurements of a single quantum spin using Josephson oscillations.

We consider a single localized spin-1/2 between the singlet superconducting leads of a Josephson junction (e.g., a superconducting STM). For the spin subject to a dc magnetic field B parallel z, we study the spin dynamics and the possibility to measure the spin state via transport through the junction embedded in a dissipative circuit. Turning on the tunneling or a voltage bias induces oscillations of the Josephson current, with an amplitude sensitive to the initial value of the z component of the spin, S(z)=+/-1/2. At low temperatures, when effects of quasiparticles are negligible, this procedure realizes a quantum nondemolition measurement of S(z).

Journal Article↗

PubMed2004

Search for pi(0)-->nu(mu)nu(mu) decays in the LSND detector.

We observe a net beam excess of 8.7+/-6.3(stat)+/-2.4(syst) events, above 160 MeV, resulting from the charged-current reaction of nu(micro) and/or nu;(mu) on C and H in the LSND detector. No beam-related muon background is expected in this energy regime. Within an analysis framework of pi(0)-->nu(mu)nu;(mu), we set a direct upper limit for this branching ratio of Gamma(pi(0)-->nu(mu)nu;(mu))/Gamma(pi(0)-->all)<1.6 x 10(-6) at 90% confidence level.

Journal Article↗

PubMed2004

Phase II study of topotecan and paclitaxel for recurrent, persistent, or metastatic cervical carcinoma.

OBJECTIVE: This trial investigated the safety and efficacy of paclitaxel and topotecan combination chemotherapy for patients with advanced cervical cancer (ACC). METHODS: Patients with recurrent, persistent, or metastatic ACC and an ECOG performance status < or =2 were treated with 175 mg/m(2) paclitaxel on Day 1 and 1 mg/m(2) topotecan on Days 1-5 of a 21-day cycle with G-CSF support and the standard pretreatment regimen for paclitaxel. Patients were treated until disease progression or unacceptable toxicity. RESULTS: Fifteen patients were enrolled, and 86 cycles of therapy (median, 5; range, 1-14) were administered. Grade 3/4 toxicities included anemia (47%), leukopenia (27%), neurotoxicity (13%), thrombocytopenia (13%), and diarrhea (13%). Among 13 evaluable patients, 7 (54%) responded (1 complete and 6 partial; 95% confidence interval = 29.2%, 76.8%). Three (23%) patients experienced stable disease. Progression-free and overall survival were 3.77 and 8.62 months, respectively. CONCLUSION: The combination of paclitaxel/topotecan was generally well tolerated and active in the relapsed, recurrent, or metastatic ACC setting, with response rates comparable with those of other current ACC systemic therapies.

Adenocarcinoma↗

PubMed2004

Cyclosporine and mycophenolate mofetil prophylaxis with fludarabine and melphalan conditioning for unrelated donor transplantation: a prospective study of 22 patients with hematologic malignancies.

In an attempt to decrease toxicity in high-risk patients undergoing unrelated donor hematopoietic stem cell transplantation (URD HSCT), we tested a combination of cyclosporine (CSP) and mycophenolate mofetil (MMF) as graft-versus-host disease (GVHD) prophylaxis with the reduced-intensity conditioning regimen fludarabine/melphalan (Flu/Mel). A total of 22 adult patients with advanced myeloid (n=15) and lymphoid (n=7) malignancies were treated. All patients received Flu 25 mg/m2 for 5 days and Mel 140 mg/m2, with CSP 3 mg/kg daily and MMF 15 mg/kg three times a day. The median age was 49 years (range 18-66). Durable engraftment was seen in all but one patient with myelofibrosis. The 1-year nonrelapse mortality was 32%, 27% from GVHD. The cumulative incidence of acute GVHD grade 2-4 and 3-4 was 63 and 41%, respectively. With a median follow-up of 18 months, the disease-free survival (DFS) and overall survival (OS) are 55 and 59%, respectively. For patients with AML and MDS (n=14), the DFS and OS is 71%. For patients undergoing a second transplant (n=14), the DFS and OS is 57%. In conclusion, this regimen is associated with acceptable toxicity but high rates of GVHD in high-risk patients undergoing URD HSCT. Encouraging disease control for patients with advanced myeloid malignancies was observed.

Adolescent↗

PubMed2004

Determination of 14C residue in eggs of laying hens administered orally with [14C] sulfaquinoxaline.

Ten layer hens were dosed for 5 consecutive days with 6.2 mg kg(-1) [14C] sulfaquinoxaline (SQX). Eggs were collected from the hens during the 5-day dosing period and during a 10-day post-dose withdrawal period. Egg yolk and albumen were separated and assayed for total radioactive residues (TRR) using a combustion oxidizer and liquid scintillation counting techniques. Significant amounts of radioactivity were detected on the second day of dosing (greater than 24h after the initial dose) in both egg yolk and albumen. First eggs were collected about 8 h after dosing; the second-day eggs were collected during 8-h period after the second dose. Radioactive residues reached a maximum on the fifth day of dosing in albumen, whereas on the second day of withdrawal in egg yolk, the peak TRR levels in albumen were about threefold higher than in yolk. Thereafter, the TRR levels declined rapidly in albumen and were detectable up to withdrawal day 6, whereas the TRR levels in egg yolk declined more slowly and were detectable up to withdrawal day 10. High-performance liquid chromatography analysis indicated that the parent drug sulfaquinoxaline was the major component in both the egg albumen and yolk. Additionally, this work suggests that egg yolk is the appropriate matrix for monitoring SQX residues

Administration, Oral↗

PubMed2004

Detection of depleted uranium in urine of veterans from the 1991 Gulf War.

American soldiers involved in "friendly fire" accidents during the 1991 Gulf War were injured with depleted-uranium-containing fragments or possibly exposed to depleted uranium via other routes such as inhalation, ingestion, and/or wound contamination. To evaluate the presence of depleted uranium in these soldiers eight years later, the uranium concentration and depleted uranium content of urine samples were determined by inductively coupled plasma mass spectrometry in (a) depleted uranium exposed soldiers with embedded shrapnel, (b) depleted uranium exposed soldiers with no shrapnel, and (c) a reference group of deployed soldiers not involved in the friendly fire incidents. Uranium isotopic ratios measured in many urine samples injected directly into the inductively coupled plasma mass spectrometer and analyzed at a mass resolution m/delta m of 300 appeared enriched in 235U with respect to natural abundance (0.72%) due to the presence of an interference of a polyatomic molecule of mass 234.81 amu that was resolved at a mass resolution m/delta m of 4,000. The 235U abundance measured on uranium separated from these urines by anion exchange chromatography was clearly natural or depleted. Urine uranium concentrations of soldiers with shrapnel were higher than those of the two other groups, and 16 out of 17 soldiers with shrapnel had detectable depleted uranium in their urine. In depleted uranium exposed soldiers with no shrapnel, depleted uranium was detected in urine samples of 10 out of 28 soldiers. The median uranium concentration of urines with depleted uranium from soldiers without shrapnel was significantly higher than in urines with no depleted uranium, though substantial overlap in urine uranium concentrations existed between the two groups. Accordingly, assessment of depleted uranium exposure using urine must rely on uranium isotopic analyses, since urine uranium concentration is not an unequivocal indicator of depleted uranium presence in soldiers with no embedded shrapnel.

Firearms↗

PubMed2004

Abnormal regulation of thirst and vasopressin secretion following surgery for craniopharyngioma.

OBJECTIVE: In this study we aimed to establish the frequency of postoperative diabetes insipidus and the incidence and characteristics of abnormalities of thirst in a cohort of patients with craniopharyngioma, in whom neurosurgery had been performed. DESIGN: Diabetes insipidus was determined by either standard criteria for diagnosis in the immediate postoperative period, or by water deprivation test, in all craniopharyngioma and pituitary tumour patients who underwent surgery in Beaumont Hospital between the years 1986 and 1998. Osmoregulated thirst and vasopressin release were studied during a 2-h infusion of hypertonic (5%) saline followed by a 30-min period of free access to water. PATIENTS: Data on the incidence of postoperative diabetes insipidus was collected in 26 patients with craniopharyngioma and 154 patients with pituitary adenomata. We recruited 16 healthy control patients, 16 patients with cranial diabetes insipidus following pituitary tumour surgery and 16 patients with cranial diabetes insipidus following craniopharyngioma resection for the hypertonic saline infusion study. RESULTS: Twenty-five patients out of 26 (96%) patients developed diabetes insipidus after surgery for craniopharyngioma, a much higher incidence than after surgery for suprasellar (26/88, 30%, P < 0.001) or intrasellar pituitary tumours (9/66, 14%, P < 0.001). Hypertonic saline infusion identified abnormal thirst responses in five of the 16 craniopharygioma patients studied; all of the pituitary tumour patients had a normal thirst response. Three of the craniopharyngioma patients had adipsic diabetes insipidus whilst two had polydipsic diabetes insipidus. CONCLUSION: This study demonstrates following surgery for craniopharyngioma there is a high incidence of cranial diabetes insipidus and a significant incidence of abnormal thirst responses to osmotic stimuli.

Adult↗

PubMed2004

An evaluation of the use of tooth temperature to assess human pulp vitality.

AIM: To evaluate change in tooth surface temperature following a thermal stimulus as a simple and reliable method to assess the presence and the extent of blood flow through teeth. METHODOLOGY: Miniature thermometers were used to measure the relationship between surface temperature of teeth and internal flow of 37 degrees C water (in vitro) or blood (in vivo). In addition, thermal stimuli were applied to the external surface of the teeth, and the rate of temperature recovery was related to internal flow. RESULTS: Under in vitro conditions, the surface temperature of teeth and rate of temperature recovery were related to the rate of internal water flow. However, in vivo neither standing surface temperature (P = 0.47) nor rate of temperature recovery (P = 0.19) were significantly related to evidential pulp vitality. CONCLUSION: Change in the surface temperature of teeth is not suitable as a simple clinical means to assess pulp vitality.

Adult↗

PubMed2004

Validity and factor structure of the bodybuilding dependence scale.

OBJECTIVES: To investigate the factor structure, validity, and reliability of the bodybuilding dependence scale and to investigate differences in bodybuilding dependence between men and women and competitive and non-competitive bodybuilders. METHODS: Seventy two male competitive bodybuilders, 63 female competitive bodybuilders, 87 male non-competitive bodybuilders, and 63 non-competitive female bodybuilders completed the bodybuilding dependence scale (BDS), the exercise dependence questionnaire (EDQ), and the muscle dysmorphia inventory (MDI). RESULTS: Confirmatory factor analysis of the BDS supported a three factor model of bodybuilding dependence, consisting of social dependence, training dependence, and mastery dependence (Q = 3.16, CFI = 0.98, SRMR = 0.04). Internal reliability of all three subscales was high (Cronbach's alpha = 0.92, 0.92, and 0.93 respectively). Significant (p<0.001) and moderate correlations were found between all BDS and MDI subscales, and between five of the eight EDQ subscales. A multivariate analysis of covariance, with univariate F tests and Tukey HSD tests, revealed that both male and female competitive bodybuilders scored significantly (p<0.05) higher on all three BDS subscales than the male and female non-competitive bodybuilders. However, there were no significant sex differences on any of the BDS subscales (p>0.05). CONCLUSION: The three factor BDS appears to be a reliable and valid measure of bodybuilding dependence. Symptoms of bodybuilding dependence are more prevalent in competitive bodybuilders than non-competitive ones, but there are no significant sex differences in bodybuilding dependence.

Adult↗

PubMed2004

Threshold contrast detail detectability curves for fluoroscopy and digital acquisition using modern image intensifier systems.

Threshold contrast detail detectability (TCDD) test objects are a commonly used tool to assess image quality of imaging systems. FAXIL (The Facility for the Assessment of X-ray imaging, Leeds) produced updated standard TCDD curves, for fluoroscopy systems in good adjustment, in 1992. Fluoroscopy curves can be corrected to account for the effect of image intensifier input air kerma rate and field size. This paper presents updated TCDD curves for fluoroscopy and new curves for digital acquisition. The results for digital acquisition suggest that the TCDD curves should not be corrected for input air kerma, as the quantum noise is not dominant and system noise is significant. These curves will prove useful for accepting new equipment, to give an indication of the expected image quality for a new image intensifier system.

Fluoroscopy↗

PubMed2004

Neurocysticercosis: a rare cause of seizure.

Neurocysticercosis is endemic in certain parts of the world, is rare in Europe and has never previously been described in the Irish healthcare setting. We report the case of a healthy male, originally from Guatemala, who presented to our hospital with a generalized tonic-clonic seizure presumed secondary to neurocysticercosis.

Adult↗

PubMed2003

Prevalence and clinical features of HTLV neurologic disease in the HTLV Outcomes Study.

BACKGROUND: Almost 20 years after its discovery, the prevalence and clinical course of human T-lymphotropic virus type I (HTLV-I)-associated myelopathy (HAM, also known as tropical spastic paraparesis [TSP]) remain poorly defined. Whereas the causative association of HTLV-I and HAM/TSP is generally recognized, controversy still surrounds the relationship between HTLV-II and HAM/TSP. METHODS: The HTLV Outcomes Study (HOST-formerly Retrovirus Epidemiology Donor Study [REDS]) is a prospective cohort study including 160 patients with HTLV-I, 405 patients with HTLV-II, and 799 uninfected controls who have been followed every 2 years since 1990-1992. Clinical outcomes are measured by health interviews and examinations, and blood samples are obtained. RESULTS: Six cases of HTLV-I-associated myelopathy (3.7%, 95% CI 1.4 to 8.0) and four cases of HTLV-II myelopathy (1.0%, 95% CI 0.3 to 2.5) have been diagnosed since the formation of the cohort. There have been no cases of HAM/TSP diagnosed among HTLV-negative subjects (0.0%, 95% CI 0.0 to 0.5). Clinical features of the cases include lower extremity hyperreflexia, variably associated with weakness, spasticity, and bladder dysfunction. CONCLUSIONS: Systematic screening of HTLV-infected blood donors reveals a high prevalence of HAM/TSP. The clinical course of HAM/TSP appears highly variable. HTLV-II-associated myelopathy generally presents with milder and more slowly progressive signs and symptoms.

Adolescent↗

PubMed2003

An animal evaluation of a paste of chitosan glutamate and hydroxyapatite as a synthetic bone graft material.

The objective of this study was to develop a synthetic bone graft in a paste form. Reported here are the results of the evaluation of a paste of chitosan glutamate (Protosan) and hydroxyapatite (referred to as a paste) used in a critical size defect model in rats. Eight-millimeter--diameter cranial defects were made in rat calvaria following a protocol approved by the animal review committee. Five groups were studied: (1) empty control, (2) defect filled with paste only, (3) defect filled with the paste containing bone-marrow aspirate, (4) defect filled with paste containing BMP-2, and (5) defect filled with paste containing osteoblasts cultured from bone-marrow aspirate. The sacrifice intervals were 9 and 18 weeks. Calvaria containing the defect were harvested, and the bone mineral density (BMD) was determined by dual energy X-ray absorptiometry. Push-out strength measurements were also performed. The BMD values of empty control were significantly lower than those of other groups at both 9 and 18 weeks. The mechanical properties, that is, push-out strengths and area under the push-out load and displacement were not significantly different between the samples. Histological examination of Goldner-trichromestained undecalcified sections showed the presence of mineralized bone spicules in the defect areas that were more prominent in those filled with paste and osteoblasts cultured from bone-marrow aspirate. Hence, this study demonstrated that the paste of chitosan glutamate and hydroxyapatite-containing osteoblasts cultured from bone-marrow aspirate would be an effective material to repair bone defects.

Animals↗

PubMed2003

ACE-Asia intercomparison of a thermal-optical method for the determination of particle-phase organic and elemental carbon.

A laboratory intercomparison of organic carbon (OC) and elemental carbon (EC) measurements of atmospheric particulate matter samples collected on quartz filters was conducted among eight participants of the ACE-Asia field experiment The intercomparison took place in two stages: the first round of the intercomparison was conducted when filter samples collected during the ACE-Asia experiment were being analyzed for OC and EC, and the second round was conducted after the ACE-Asia experiment and included selected samples from the ACE-Asia experiment Each participant operated ECOC analyzers from the same manufacturer and utilized the same analysis protocol for their measurements. The precision of OC measurements of quartz fiber filters was a function of the filter's carbon loading but was found to be in the range of 4-13% for OC loadings of 1.0-25 microg of C cm(-2). For measurements of EC, the precision was found to be in the range of 6-21% for EC loadings in the range of 0.7-8.4 microg of C cm(-2). It was demonstrated for three ambient samples, four source samples, and three complex mixtures of organic compounds that the relative amount of total evolved carbon allocated as OC and EC (i.e., the ECOC split) is sensitive to the temperature program used for analysis, and the magnitude of the sensitivity is dependent on the types of aerosol particles collected. The fraction of elemental carbon measured in wood smoke and an extract of organic compounds from a wood smoke sample were sensitive to the temperature program used for the ECOC analysis. The ECOC split for the three ambient samples and a coal fly ash sample showed moderate sensitivity to temperature program, while a carbon black sample and a sample of secondary organic aerosol were measured to have the same split of OC and EC with all temperature programs that were examined.

Carbon↗