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Biomedical subjects

M J Murphy

Publications and source records attributed to M J Murphy.

At least 37 records · Page 2Linked to original sources
PubMed2000

Aneurysmal bone cyst of the spine with familial incidence.

STUDY DESIGN: A report of two cases of aneurysmal bone cysts of the spine occurring in a father and daughter. OBJECTIVE: To present an unusual finding of familial incidence of aneurysmal bone cyst and review the literature. SUMMARY OF BACKGROUND DATA: Aneurysmal bone cysts are benign, expanding, locally aggressive lesions. Up to 20% of cases involve the spine. The cause of primary aneurysmal bone cysts remains unclear. There have been three previous reports of a familial incidence supporting the importance of a hereditary component in the cause of aneurysmal bone cysts. METHODS: A 36-year-old man and a 7-year-old girl were diagnosed with aneurysmal bone cyst involving the spine by clinical manifestations, radiographic features, and histologic evaluation. RESULTS: The father remains recurrence- and symptom-free 6 years after primary resection. Five months after surgery, the daughter was found to have recurrent disease by magnetic resonance imaging and underwent a second procedure within 1 year of the primary resection. CONCLUSION: The occurrence of a primary aneurysmal bone cyst in two family members, occurring at adjacent vertebral levels, is suggestive of a hereditary component to the formation of primary aneurysmal bone cyst.

Adult↗
PubMed2000

Robotic motion compensation for respiratory movement during radiosurgery.

Tumors in the chest and abdomen move during respiration. The ability of conventional radiation therapy systems to compensate for respiratory motion by moving the radiation source is inherently limited. Since safety margins currently used in radiation therapy increase the radiation dose by a very large amount, an accurate tracking method for following the motion of the tumor is of the utmost clinical relevance. We investigate methods to compensate for respiratory motion using robotic radiosurgery. Thus, the therapeutic beam is moved by a robotic arm, and follows the moving target tumor. To determine the precise position of the moving target, we combine infrared tracking with synchronized X-ray imaging. Infrared emitters are used to record the motion of the patient's skin surface. A stereo X-ray imaging system provides information about the location of internal markers. During an initialization phase (prior to treatment), the correlation between the motions observed by the two sensors (X-ray imaging and infrared tracking) is computed. This model is also continuously updated during treatment to compensate for other, non-respiratory motion. Experiments and clinical trials suggest that robot-based methods can substantially reduce the safety margins currently needed in radiation therapy.

Humans↗
PubMed2000

Image-guided radiosurgery for the spine and pancreas.

A robotic image-guided radiosurgical system has been modified to treat extra-cranial sites using implanted fiducials and skeletal landmarks to locate the treatment targets. The system has been used to treat an artero-venous malformation in the cervical spine, a recurrent schwannoma of the thoracic spine, a metastatic adenocarcinoma of the lumbar spine, and three pancreatic cancers. During each treatment, the image guidance system monitored the position of the target site and relayed the target coordinates to the beam-pointing system at discrete intervals. The pointing system then dynamically aligned the therapy beam with the lesion, automatically compensating for shifts in target position. Breathing-related motion of the pancreas lesions was managed by coordinating beam gating with breath-holding by the patient. The system maintained alignment with the spine lesions to within +/- 0.2 mm on average, and to within +/- 1 mm for the pancreatic tumors. This experience has demonstrated the feasibility of using image-guided robotic radiosurgery outside the cranium.

Adenocarcinoma↗
PubMed2000

Postprandial response to a fat tolerance test in young adults with a paternal history of premature coronary heart disease - the EARS II study (European Atherosclerosis Research Study).

BACKGROUND: The European Atherosclerosis Research Study (EARS) I had shown that fasting plasma concentrations of apolipoprotein B (apo B) and triglycerides were the most discriminant variables between offspring with a paternal history of coronary heart disease (CHD) and controls. The EARS II study was undertaken to investigate whether a paternal history of CHD was associated with differences in postprandial lipemia. DESIGN: Male subjects with a paternal history of CHD (cases, n = 407) and age-matched male controls (n = 415) were recruited from 14 European universities. All subjects had an oral fat tolerance test. RESULTS: In the sample as a whole, the postprandial triglyceride responses did not significantly differ between the two groups. However, in the upper tertile of fasting triglycerides, cases displayed a higher area under the curve (5.71 vs. 4.49 mmol.h L-1, P < 0.001), a higher peak (1.76 vs. 1.43 mmol L-1, P < 0.001) and a more delayed time to peak (3.15 vs. 2.91 h, P < 0.05) than controls. In the upper tertile, fasting apo B levels (P < 0.05) and triglyceride area under the curve (P = 0.002) significantly discriminated cases from controls in a multivariate analysis. Cases had also higher Lp C-III:B levels at 4 h than controls (11.2 vs. 9.9 mg dL-1, P < 0.01) and this difference remained significant after adjustment for apo B and triglyceride levels. CONCLUSIONS: These results indicate that in subjects with a moderate elevation of fasting triglycerides, an impaired postprandial response to a fat load constitutes an early biological expression of a paternal history of premature CHD.

Administration, Oral↗
PubMed2000

Midfacial tumours: a review of 72 cases.

We review 72 midfacial tumours managed during the 10-year period between 1985 and 1995. We describe presenting features, sites of lesions and histology, treatment regimens and outcomes, as well as the various surgical approaches for the resection of midfacial tumours, and their indications and contraindications. The choice of approach should be based on type of tumour, its site, and extent.

Adolescent↗
PubMed2000

Effects of dexamethasone on development of immunoglobulin G subclass responses following vaccination of horses.

OBJECTIVE: To determine the effects of dexamethasone on development of IgG subclass responses following vaccination of healthy horses. ANIMALS: 11 mature Thoroughbreds. PROCEDURE: Horses received 2 IM injections at 2-week intervals of a vaccine containing inactivated infectious bovine rhinotracheitis, bovine viral diarrhea, and parainfluenza-3 viral antigens and were then randomly assigned to 2 groups. Six horses received dexamethasone (0.2 mg/kg of body weight, IM) twice weekly for 8 weeks starting the day of the first vaccination. Five control horses received an equivalent volume of saline (0.9% NaCl) solution. Antigen-specific serum IgG subclass titers were determined weekly after vaccination by use of an ELISA. RESULTS: Vaccination resulted in similar antigen-specific serum IgG(T) titers in dexamethasone-treated and control horses. In contrast, although control horses developed IgGa and IgGb responses after vaccination, corticosteroid administration completely inhibited these responses in treated horses. CONCLUSIONS AND CLINICAL RELEVANCE: Cortico steroids can have profound effects on primary immune responses in horses and can significantly affect IgG responses to inactivated vaccines. Corticosteroid treatment regimens commonly used to treat diseases in horses may result induction of a nonprotective IgG subclass response, leaving treated horses susceptible to disease. Additionally, mechanisms regulating IgGa and IgGb responses appear to differ from those regulating IgG(T) responses. Further defining these mechanisms is a critical step in designing effective vaccines, and corticosteroid-induced immunomodulation may be a valuable tool for studying immune responses in horses.

Animals↗
PubMed2000

Health and environmental implications of using composted household and yard waste bedding in a cattle feedlot.

A study was conducted to determine the safety and feasibility of using municipal solid waste compost (MSWC) as a bedding material for cattle feedlots. Two pens in an open-front pole barn were bedded with either corn stalks or MSWC in each of two feeding periods (blocks) with two pens (23 x 34 m) per block. Block 1 used 336 heifers (initial BW, 398 kg) during a 104-d period (summer), and Block 2 used 276 steers (initial BW, 412 kg) during a 92-d period (winter). Blood concentrations of regulated elements (Cd, Cu, Mo, Pb, Ni, and Zn), electrolytes, glucose, or liver and kidney enzymes were unaffected (P > .05) by use of either bedding material. Polychlorinated biphenyls in perirenal fat were not detectable (< .5 ppm) in cattle bedded with either material. At slaughter, kidney Cu and kidney and liver Pb concentrations were greater (P < .05) for cattle bedded with MSWC. Despite this, tissue concentrations of these elements were well within those considered normal for healthy cattle. Regulated element concentrations of feed did not differ (P > .05) between diets within period, and neither did DMI or DM digestibility; therefore, cattle bedded with MSWC were likely inhaling additional amounts of these elements and excreting them through feces. More MSWC than corn stalks was required to supply a dry bed per animal daily (P < .05). Soiled bedding (manure as-is) output was similar (P > .05) for both bedding materials. On a DM basis, more manure (P < .05) was removed from the pen bedded with MSWC in Block 2. Total manure N and P removed was similar for both bedding materials. Nitrogen and P concentrations in manure were lower (P < .05) during Block 2, but total manure N removed was greater (P < .05) during Block 2. Total manure P removed from the pens was not affected by season. Under the conditions of this study, MSWC seemed to be a safe and effective bedding material for cattle feedlots.

Animal Husbandry↗
PubMed1999

The importance of computed tomography slice thickness in radiographic patient positioning for radiosurgery.

A new radiographic patient positioning technique developed for radiosurgery has been analyzed to show the effect of computed tomography (CT) slice thickness on the precision of target localization during treatment. The positioning technique establishes the pose of the patient's anatomy during treatment by comparing treatment room radiographs with digitally reconstructed radiographs derived from a CT study. The measured pose is then used to align the x-ray therapy beam with the treatment site, without resorting to mechanical fixation. The technique has been found to be sensitive to submillimeter changes in skull position, which is the level of precision desired for radiosurgery. In this report it is shown that the precision of head localization improves by a factor of 2 when the CT slice thickness is reduced from 3.0 to 1.5 mm. This indicates that, in radiosurgical applications, image-guided beam alignment can be significantly influenced by the spatial resolution of the reference CT study. This result is relevant to all high-precision radiographic positioning techniques that utilize CT images.

Algorithms↗
PubMed1999

Efficacy of statin therapy: possible effect of phenytoin.

Statins are currently the most widely prescribed lipid-lowering drugs. Individual statins are known to be metabolised by the CYP3A4 isoform of the cytochrome P450 system. The effect of CYP3A4 inducers such as phenytoin on the metabolism and efficacy of these agents is unknown. We report a patient with familial hypercholesterolaemia and epilepsy in whom the introduction and subsequent discontinuation of phenytoin were associated with marked changes in the lipid response to treatment with simvastatin and atorvastatin. The serum activity of gamma-glutamyl transpeptidase may have acted as a marker of microsomal induction by phenytoin, since it rose markedly when phenytoin was introduced and returned to normal after it was discontinued.

Anticholesteremic Agents↗
PubMed1999

Use of measurements of myoglobin and cardiac troponins in the diagnosis of acute myocardial infarction.

Research indicates that no tests of a single cardiac marker are 100% specific and sensitive for diagnosis of AMI in all patients. Each biomarker has advantages and disadvantages (see Table). Over-reliance on a single diagnostic test is risky. Specific tests should be ordered on the basis of the individual patient's assessment and medical history. Nurses are an important link in the collection of patients' medical history and in assessment as well as in the interpretation of patients' laboratory results. A knowledge of diagnostic tests commonly used in the care of patients with ischemic heart disease is imperative if patients are to receive appropriate, timely, cost-effective care.

Biomarkers↗
PubMed1998

Pyrimidine thioethers: a novel class of HIV-1 reverse transcriptase inhibitors with activity against BHAP-resistant HIV.

A series of pyrimidine thioethers was synthesized and evaluated for inhibitory properties against wild-type HIV-1 reverse transcriptase (RT) and an RT carrying the resistance-conferring mutation P236L. Modifications of both the pyrimidine and the functionality attached through the thioether yielded several analogues, which demonstrated activity against both enzyme types, with IC50 values as low as 190 nM against wild-type and 66 nM against P236L RT. Evaluation of a select number of pyrimidine thioethers in cell culture showed that these compounds have excellent activity against HIV-1IIIB-WT and retain good activity against a laboratory-derived HIV-1MF delavirdine-resistant variant.

Amino Acid Substitution↗
PubMed1998

Specific assays for bacteria using phage mediated release of adenylate kinase.

A sensitive and rapid assay method for the specific detection of bacteria was developed using Escherichia coli and Salmonella newport as the test organisms. Bacteriophages were used to provide specific lysis of the bacteria and then the release of cell contents was measured by ATP bioluminescence. Increased sensitivity was obtained by focusing on the bacteria's adenylate kinase (AK) as the cell marker instead of ATP as conventionally used. Fewer than 10(3) E. coli cells could be readily detected in less than 1 h. Salmonella newport assays, although as sensitive, were slower and took up to 2 h. The effects of the culture medium, the phage, and the presence of non-specific bacteria were examined.

Adenylate Kinase↗
PubMed1997

Health promotion and older people: a qualitative study of general practitioners' views.

OBJECTIVES: To explore general practitioners' (GPs') beliefs about health promotion for older people and attitudes towards educational strategies likely to improve practice in this area. DESIGN AND SETTING: Four discussion groups, each lasting one and a half hours, completed in Melbourne, Australia in August and September 1995. Interviews were transcribed verbatim and analysed for major themes. PARTICIPANTS: A convenience sample of 20 GPs took part; 11 university affiliates, four participant contacts and five GPs from telephone book listings. RESULTS: GPs' perceptions of their health promotion practice varied from "integrated into all medical care", to "something separate from usual practice". Positive views of older people contrasted with ageist views, with a few GPs expressing a nihilistic approach to medical care of older people. Regardless of the GPs' attitudes, lack of time and reimbursement disincentives were perceived to limit preventive practice and the potential impact of health promotion interventions. GPs felt overwhelmed with their workloads, and initial reactions to the idea of any "new" program were negative. Reactions to educational strategies varied, with choice and relevance to ease of practice being important for GP participation. CONCLUSIONS: GPs differ in their views of health promotion and in their approaches to its delivery for older people. Educational programs are often viewed negatively, but if they offer the opportunity to save time, increased participation may be more likely.

Aged↗