PubMed Health⌕ Search

Biomedical subjects

J McGinley

Publications and source records attributed to J McGinley.

At least 19 recordsLinked to original sources
PubMed2005

Cyclotron production of Ac-225 for targeted alpha therapy.

The feasibility of producing Ac-225 by proton irradiation of Ra-226 in a cyclotron through the reaction Ra-226(p,2n)Ac-225 has been experimentally demonstrated for the first time. Proton energies were varied from 8.8 to 24.8 MeV and cross-sections were determined by radiochemical analysis of reaction yields. Maximum yields were reached at incident proton energies of 16.8 MeV. Radiochemical separation of Ac-225 from the irradiated target yielded a product suitable for targeted alpha therapy of cancer.

Actinium↗
PubMed2004

Production of electrical energy from carbohydrates using a transition metal-catalysed liquid alkaline fuel cell.

Biomass may be converted to energy by enzymatic hydrolysis to monomer components and fermentative conversion of those products to ethanol for use as fuel. Both glucose and xylose in aqueous solution were directly converted to electrical energy using a liquid alkaline fuel cell (AFC) at room temperature. Hydrolysis products derived from the action of cellulase and amylase on cellulose and starch, respectively, were also used as fuels in the AFC system. We suggest that this approach may provide a more direct means of accessing some of the energy available from biomass.

Alkalies↗
PubMed2001

Design and initial evaluation of a low-cost 3-Tesla research system for combined optical and functional MR imaging with interventional capability.

A 3-Tesla research system has been developed for functional and interventional magnetic resonance imaging (MRI) procedures on animal models based on a low field niche spectrometer. Use of two stages of fourth harmonic frequency multiplication has allowed us to produce a high-frequency spectrometer with good frequency stability based on a low-frequency direct digital synthesizer. The system has been designed with the ability to introduce interventional tools such as biopsy needles, radiofrequency (RF) electrodes, and fiber optics for optical spectroscopy and thermal ablation as well as drug infusions to allow function to be studied in the presence of external challenges. Full MR-compatible physiologic support capability allows animals to be maintained in a stable condition over extended periods of study. Functional MR images have been acquired by using gradient echoes (TR/TE = 40/12 msec) from the rat whisker barrel cortex using electrical stimulation (5-V, 1.5-mA, 1-msec pulses at 5 Hz via two needle electrodes inserted into the rat whisker pad). Initial results using respiratory gas challenges of 100% N(2), 100% O(2), and 10% CO(2) have shown excellent agreement between single wavelength (633 nm) optical and functional MR time series with subsecond time resolution. The 1-mm copper electrodes for interventional radiofrequency ablation procedures were easily visualized in the superior colliculus by using gradient echo sequences. This novel, low-cost, high field system appears to be a useful research tool for functional and interventional studies of rat brain and allows concurrent optical spectroscopy. J. Magn. Reson. Imaging 2001;13:87-92.

Animals↗
PubMed2001

Dopexamine hydrochloride does not modify hemodynamic response or tissue oxygenation or gut permeability during abdominal aortic surgery.

PURPOSE: To assess the effects of intraoperative infusion of dopexamine (a DA-1 and B2 adrenoreceptor agonist) on hemodynamic function, tissue oxygen delivery and consumption, splanchnic perfusion and gut permeability following aortic cross- clamp and release. METHODS: In a randomised double blind controlled trial 24 patients scheduled for elective infrarenal abdominal aortic aneurysm repair were studied in two centres and were assigned to one of two treatment groups. Group I received a dopexamine infusion starting at 0.5 microg x kg(-1) x min(-1) increased to 2 microg x kg(-1) x min(-1) maintaining a stable heart rate; Group II received a placebo infusion titrated in the same volumes following induction of anesthesia. Measured and derived hemodynamic data, tissue oxygen delivery and extraction and gut permeability were recorded at set time points throughout the procedure. RESULTS: Dopexamine infusion (0.5 -2 microg x kg x min(-1)) was associated with enhanced hemodynamic function (MAP 65 +/- 5.5 vs 92 +/- 5.7 mm Hg, P = <0.05) only during the period of aortic cross clamping. However, during the most part of infrarenal abdominal aortic surgery, dopexamine did not reduce systemic vascular resistance index, mean arterial pressure nor oxygen extraction compared with the control group. The lactulose/ rhamnose permeation ratio was elevated above normal in both groups (0.22 and 0.29 in groups I and II respectively). CONCLUSIONS: Dopexamine infusion (0.5 -2 microg x kg(-1) x min(-1)) did not enhance hemodynamic function and tissue oxygenation values during elective infrarenal abdominal aortic aneurysm repair.

Aged↗
PubMed2001

The biomechanics and motor control of gait in Parkinson disease.

Parkinson disease is a progressive neurological condition characterised by hypokinesia (reduced movement), akinesia (absent movement), tremor, rigidity and postural instability. These movement disorders are associated with a slow short-stepped, shuffling gait pattern. Analysis of the biomechanics of gait in response to medication, visual cues, attentional strategies and neurosurgery provides insight into the nature of the motor control deficit in Parkinson disease and the efficacy of current therapeutic interventions. In this article we supplement a critical evaluation of the Parkinson disease gait literature with two case examples. The first case describes the kinematic gait response of an individual with Parkinson disease to visual cues in the "off" phase of the levodopa medication cycle. The second case investigates the biomechanics and motor control of turning during walking in a patient with Parkinson disease compared with elderly and young control subjects. The results are interpreted in light of the need for gait analysis to investigate complex functional walking tasks rather than confining assessment to straight line walking, which has been the trend to date.

Biomechanical Phenomena↗
PubMed2001

A case of pneumomediastinum in paediatric ARDS: to oscillate or not?

An 18-month-old was transferred (intubated and ventilated) to our hospital with staphylococcal tracheitis, which progressed to a necrotizing pneumonitis, complicated by surgical emphysema and pneumomediastinum. Maximum conventional ventilation on a Servo 300 failed. Treatment with high frequency oscillatory ventilation (for 10 days) with a permissive hypercarbia and hypoxaemia strategy to limit mean airway pressure facilitated recovery in our patient.

Female↗
PubMed2001

Myopia and night-time lighting during sleep in children and adults.

This cross-sectional study investigated the relationship between different lighting conditions experienced during sleep in the first -two years of life and development of myopia after age two as reported retrospectively by parents in a total of 469 individuals, including 252 children aged 2-16 yr., and 217 adults aged 17-40 yr. There were no significant differences in incidence of myopia in children who had slept from 0-2 yr. in darkness, with a night light, room light, or hall light. Adults who were reported by their parents to have slept with a night light on from 0-2 yr. were significantly more likely to be myopic than those who were reported to have slept from 0-2 yr. in any other lighting condition.

Adolescent↗
PubMed2000

Classification of premalignant and malignant lesions developing in the rat mammary gland after injection of sexually immature rats with 1-methyl-1-nitrosourea.

Premalignant and malignant stages of mammary carcinogenesis can be rapidly induced by injecting female rats i.p. with 1-methyl-1-nitrosourea (MNU)3 at 21 days of age. In this paper, the characteristics of this model are briefly reviewed and the histology of the lesions induced is presented and compared to those that occur in humans. Malignant mammary lesions induced in rats injected with MNU at 21 days of age are compared with the lesions that develop when MNU is administered to 50-day-old female rats.

Adenocarcinoma↗
PubMed1999

Cisapride does not alter gastric volume or pH in patients undergoing ambulatory surgery.

PURPOSE: To evaluate the efficacy of 20 mg cisapride p.o. in reducing residual gastric volume and pH in adult ambulatory surgical patients. METHODS: Using a prospective randomised double-blind controlled design, we administered either 20 mg cisapride p.o. or placebo preoperatively to 64 ASA 1-2 ambulatory surgical patients. Following induction of anesthesia we measured volume and pH of residual gastric contents, using blind aspiration through an orogastric tube. Parametric data were analysed using unpaired, one tail Students' t test. Non-parametric data were analysed using Fishers Exact test and Chi square analysis. Statistical significance was accepted at the probability level of < 0.05. RESULTS: Residual gastric volumes were similar in the two groups (19.5 +/- 23.8, 23.9 +/- 24.4 ml), in the cisapride and placebo groups respectively, P=0.24). Data shown are mean (+/- SD). The proportions of patients with a residual gastric volume exceeding 0.4 ml x kg(-1) were similar in the two groups (4 of 28, and 8 of 23 patients in the cisapride and placebo groups respectively, P=0.09). The pH of the residual gastric contents were similar in the cisapride and placebo groups (1.6 +/- 0.5, 1.4 +/- 0.5, respectively, P=0.26). The proportions of patients with pH < 2.5 was also similar in the cisapride and placebo groups (21 of 25, and 20 of 21 patients respectively, P=0.2). CONCLUSIONS: Preoperative administration of 20 mg cisapride p.o. to patients scheduled for outpatient surgery does not alter either the volume or the pH of gastric contents. Its use in this setting is of no apparent clinical benefit.

Adult↗
PubMed1999

The effects of ropivacaine hydrochloride on coagulation and fibrinolysis. An assessment using thromboelastography.

Amide local anaesthetics impair coagulation by inhibition of platelet function and enhanced fibrinolysis. The potential therefore exists that the presence of amide local anaesthetics in the epidural space could contribute to the therapeutic failure of an epidural autologous blood patch. Ropivacaine is an aminoamide local anaesthetic increasingly used for epidural analgesia and anaesthesia, particularly in obstetric practice. This study was undertaken to investigate whether concentrations of ropivacaine in blood, which could occur clinically in the epidural space, alter coagulation or fibrinolysis. Thromboelastography was used to assess clotting and fibrinolysis of blood to which ropivacaine had been added. Although modest alterations in maximum amplitude, coagulation time and alpha angle were observed, the effect of ropivacaine on clotting and fibrinolysis was not clinically significant. We conclude that it is unlikely that the presence of ropivacaine in the epidural space would reduce the efficacy of an early or prophylactic epidural blood patch.

Adult↗
PubMed1999

Conjugated linoleic acid-enriched butter fat alters mammary gland morphogenesis and reduces cancer risk in rats.

Conjugated linoleic acid (CLA) is a potent cancer preventive agent in animal models. To date, all of the in vivo work with CLA has been done with a commercial free fatty acid preparation containing a mixture of c9,t11-, t10,c12- and c11,t13-isomers, although CLA in food is predominantly (80-90%) the c9,t11-isomer present in triacylglycerols. The objective of this study was to determine whether a high CLA butter fat has biological activities similar to those of the mixture of free fatty acid CLA isomers. The following four different endpoints were evaluated in rat mammary gland: 1) digitized image analysis of epithelial mass in mammary whole mount; 2) terminal end bud (TEB) density; 3) proliferative activity of TEB cells as determined by proliferating cell nuclear antigen immunohistochemistry; and 4) mammary cancer prevention bioassay in the methylnitrosourea model. It should be noted that TEB cells are the target cells for mammary chemical carcinogenesis. Feeding butter fat CLA to rats during the time of pubescent mammary gland development reduced mammary epithelial mass by 22%, decreased the size of the TEB population by 30%, suppressed the proliferation of TEB cells by 30% and inhibited mammary tumor yield by 53% (P < 0.05). Furthermore, all of the above variables responded with the same magnitude of change to both butter fat CLA and the mixture of CLA isomers at the level of CLA (0.8%) present in the diet. Interestingly, there appeared to be some selectivity in the uptake or incorporation of c9,t11-CLA over t10,c12-CLA in the tissues of rats given the mixture of CLA isomers. Rats consuming the CLA-enriched butter fat also consistently accumulated more total CLA in the mammary gland and other tissues (four- to sixfold increases) compared with those consuming free fatty acid CLA (threefold increases) at the same dietary level of intake. We hypothesize that the availability of vaccenic acid (t11-18:1) in butter fat may serve as the precursor for the endogenous synthesis of CLA via the Delta9-desaturase reaction. Further studies will be conducted to investigate other attributes of this novel dairy product.

Animals↗
PubMed1998

Sunbeds in current use in Scotland: a survey of their output and patterns of use.

Spectral irradiances of 100 commercially available sunbeds in current use have been measured. Ultraviolet (UV) A and UVB doses from sunbed use have been calculated and compared with doses likely to be received from solar radiation. The majority of sunbeds use UVA fluorescent tubes for irradiating the body and filtered metal halide lamps, which have a higher proportion of UVA1, for the face. The average minimum erythemal dose per session is 0.80, but irradiances for particular models varied by a factor of two to three primarily because of decline in lamp output with age. The UVA dose from a session on a sunbed is similar to that which might be received from 20 to 30 min sunbathing at a Mediterranean resort or 1 h on a sunny day in Glasgow, while UVB doses are 20-25% of this level. Responses from 200 current users of the sunbeds indicate that 38% had skin types 1 and 2, that 17% had more than 100 annual sunbed sessions and that 35% rarely or never used the goggles provided.

Adult↗
PubMed1998

Effect of anxiety on the rate of gastric emptying of liquids.

The efficacy of preoperative fasting is reduced in the presence of any factor which delays gastric emptying. We examined the association between anxiety and gastric emptying in adult patients undergoing elective surgery. Immediately before operation, 21 patients completed both a Spielberger state trait inventory (used to quantify current anxiety state (STAIs) and anxiety predisposition (STAIt)), and the Amsterdam preoperative anxiety and information scale (used to quantify anxiety and need for information). Gastric emptying was measured using the paracetamol absorption technique. Four to 10 weeks later, gastric emptying and STAI were measured again. Patients were more anxious before than after operation (STAIs = mean 35.4 (SD 10.9) and 25 (4.1), respectively; P = 0.0004). Neither anxiety state (P = 0.40) nor measures of anxiety relative to anxiety predisposition (P = 0.86) influenced gastric emptying (as measured by area under the paracetamol absorption-time curve). This contrasts with previous findings that anxiety in patients with low anxiety predisposition scores delays gastric emptying.

Acetaminophen↗
PubMed1998

Ovarian hormone dependence of pre-malignant and malignant mammary gland lesions induced in pre-pubertal rats by 1-methyl-1-nitrosourea.

The experiments reported in this study were designed to examine the question of whether a mammary epithelial cell's independence from hormonal requirements is established at the time of carcinogenic initiation, or whether the emergence of hormone independence is associated with the process of tumor progression. A newly developed rat model of mammary carcinogenesis was used in which the latency period to lesion detection is very short and in which the frequencies of both pre-malignant and malignant mammary lesions can be quantified. Two experiments were conducted in Sprague-Dawley rats injected with 50 mg MNU/kg body wt at 21 days of age. In the first experiment 47 animals were ovariectomized after the detection of a mammary tumor of palpable size. Forty-six of the 47 tumors assessed, all of which were subsequently classified as mammary gland adenocarcinomas, regressed to <50% of their initial volume within 14 days of bilateral ovariectomy. However, both pre-malignant and malignant mammary gland lesions were observed when animals were killed. In Experiment 2 a total of 60 rats were ovariectomized 7 days after MNU was injected. At 35 days post carcinogen ovariectomized animals had a higher incidence of intraductal proliferations than sham-operated controls (P = 0.03); there was no effect of ovariectomy on the incidence of ductal carcinoma in situ or carcinoma. The multiplicity of intraductal proliferations was increased by 58% in ovariectomized rats (P = 0.12), but the number of mammary carcinoma per rat was reduced (3.8 vs. 1.57, P = 0.02). These data are consistent with the hypotheses that the progression of pre-malignant to malignant lesions is inhibited in the mammary gland by ovariectomy and that the hormone independent phenotype can be conferred at the time of carcinogenic initiation.

Adenocarcinoma↗