Search PubMed⌕ Search

Biomedical subjects

M Buchanan

Publications and source records attributed to M Buchanan.

At least 19 recordsLinked to original sources
PubMed2006

Incidence of sports injuries in elite competitive and recreational windsurfers.

OBJECTIVE: To investigate the incidence of injury in windsurfing and to consider methods of prevention. METHODS: A total of 107 raceboard (RB) and wave/slalom (WS) national/international competitors and recreational (REC) windsurfers completed a questionnaire on injury incidence over two years. Recurrent injury, ability level, and any preventive measures taken were noted. RESULTS: Overall the injury incidence was 1.5/person/year. The WS group suffered more injuries (2.0/person/year) than the RB (1.0) or REC (1.2) group. The most common injury was muscle strain at 35% of new injuries, much higher than in earlier studies. Overall 45% of new injuries were muscle/tendon strains (RB 55%, WS 42%, and REC 43%) and 8% were ligament sprains. In the WS group cuts and abrasions were common. The WS and REC groups reported five and one case of concussion respectively. Nearly a quarter (22%) of new lower body injuries were lower back muscular strain, with 34% of recurrent injuries. Approximately 60% of the remaining lower body soft tissue injuries involved the knee or lower leg, with the ankle/foot most often involved. The shoulder, upper arm, and elbow were the sites of 41% of new upper body soft tissue injuries. The WS group reported 250% more recurrent muscular strains than the RB group. Recurrent ligament injuries (particularly knee) were most common in the WS group. The RB group reported recurrent serious bruising to the lower leg. CONCLUSION: The injury incidence was 1.5/person/year with a high incidence of new and recurrent muscular strain. Lower back muscular strain was prevalent, indicating the need for preventive measures. Wave/slalom was associated with more new and recurrent injuries and the need for head protection.

Adolescent↗
PubMed2005

High-frequency microrheology of wormlike micelles.

We have measured the frequency-dependent shear modulus of entangled solutions of wormlike micelles by high-frequency microrheology and have compared the results with those from macrorheology experiments done on the same samples. Using optical microrheology based on laser interferometry we have measured loss and storage moduli over six decades in frequency up to about 100 kHz. We present data over a decade in concentration in the entangled regime and find good agreement between micro- and macrorheology, thus validating recently developed microrheology techniques. By collapsing data for different concentrations, we furthermore determine both the concentration scaling of the plateau modulus and a power-law exponent of the complex shear modulus at high frequencies.

Journal Article↗
PubMed2004

EUROPA DONNA: has strength in its heterogeneity.

EUROPA DONNA, a non-profit-making organisation, is a pan-European movement against breast cancer; it is a coalition that is active in 29 countries, each organised into national independent Fora. In each Forum, a postal survey was conducted between 2001 and 2002. A standardised questionnaire was used to collect information about Forum characteristics and activities, and perceptions of the adequacy of the local health service in relation to the prevention, diagnosis and treatment of breast cancer. Twenty-seven Fora (93%) participated in the survey. The results show the heterogeneity between the Fora in the services offered and activities in the different countries. The Fora also perceived a range of deficiencies in the prevention, diagnosis and treatment of breast cancer within their national health systems. These results highlight the importance of a coalition to establish a consensus among the Fora, and the need for coordinated initiatives in different European countries.

Breast Neoplasms↗
PubMed2001

Reliability and validity of a modified Colorado Symptom Index in a national homeless sample.

This study examined the reliability and construct validity of a modified version of the Colorado Symptom Index (MCSI), a brief, self-report measure of psychological symptomatology, in a study of interventions to prevent homelessness. Eight projects in a national, cooperative study collected new data at baseline, 6, and 12 months using a set of common measures as well as site-specific instruments. The pooled sample consisted of 1,381 persons in treatment for mental illness or substance abuse (or both), of which 84% had a history of homelessness. The analyses employed classical and Rasch methods to examine the MCSI's content validity, internal consistency and item quality, test/retest reliability, dimensionality, appropriateness for the sample, construct validity, and responsiveness to change. This 14-item scale was found to be a reliable and valid measure of psychological symptoms in this sample. Its content was consistent with other symptom measures, its high internal consistency and test-retest coefficients supported its reliability, its relationships to other measures indicated that it had good construct validity, and it was responsive to change. We conclude that the MC

Adolescent↗
PubMed2001

A randomized controlled crossover study comparing synthetic porcine and human secretins with biologically derived porcine secretin to diagnose Zollinger-Ellison Syndrome.

BACKGROUND: Although biologically-derived porcine secretin is approved for the diagnosis of Zollinger-Ellison Syndrome, it is no longer available in the United States. Pure human and porcine secretins have now been synthesized and new drug applications have been filed with the Federal Drug Administration (FDA). METHODS: In the current study we compared secretin testing results in six confirmed Zollinger-Ellison Syndrome patients using the biologically-derived product and both synthetic products (human and porcine) in a three-way, randomized, single-blind Latin-squares crossover study. RESULTS: Using the FDA-approved criterion for positive secretin testing (i.e. a serum gastrin concentration increase of > 110 pg/mL), there was complete agreement between all three agents for all patients. With the more stringent NIH criterion (i.e. a serum gastrin concentration increase of > 200 pg/mL), positive results persisted in five out of six, six out of six and four out of six patients using biologically-derived secretin, synthetic porcine secretin, and synthetic human secretin, respectively (six out of six, six out of six and four out of six if a positive test was defined as a 50% increase in serum gastrin concentration). The time to peak serum gastrin concentration after secretin injection occurred within 15 min in all studies (in 94% by 10 min and in 77% by 5 min). Three-way comparisons of serum gastrin concentrations showed a single statistically significant difference (the change from baseline at 15 min between synthetic human and synthetic porcine secretin, P=0.0274). Statistically significant changes from baseline occurred at 1, 2 and 5 min for biologically-derived porcine secretin and at 2 and 5 min for both synthetic porcine and synthetic human secretin, in keeping with the expected time curve for positive tests. All three agents were well-tolerated. CONCLUSIONS: These data suggest that either synthetic secretin product, when released onto the United States market, can be used to confirm Zollinger-Ellison Syndrome.

Adult↗
PubMed2000

High incidence of micrometastases in breast cancer sentinel nodes.

BACKGROUND: Sentinel lymph node biopsy (SLNB) is being investigated as an alternative to formal axillary dissection in early breast cancer. Avoiding the morbidity of unnecessary axillary dissection is seen as the main potential benefit of SLNB. Sentinel lymph node biopsy also allows enhanced pathological analysis. A series of 62 sentinel node (SN) biopsies demonstrating a high incidence of micrometastases is presented here. METHODS: All SN were initially examined and reported by H&E staining. All negative SN were analysed after staining with polyclonal anticytokeratin antibody. RESULTS: Sixty-two patients underwent SLNB at Royal Melbourne Hospital between May 1998 and February 2000. One or more SN was identified in 51/62 patients. A total of 10/51 contained metastases identified after H&E staining. There was one false negative. A total of 10/41 patients with H&E-negative SN had micrometastases identified on immunohistochemistry (IHC). Micrometastases were more common in patients with larger tumours, with disease found in the H&E-negative SN of 1/17 T1a and T1b (1-10 mm), 4/15 T1c (11-20 mm), and 5/9 T2 (20-50 mm) tumours. CONCLUSION: Sentinel lymph node biopsy can accurately assess the axilla in most patients with early breast cancer. A significant proportion of histologically negative SN will have micrometastases identifiable with IHC. Although the clinical significance of such metastases is uncertain, the available evidence suggests that these patients have a poorer prognosis than other patients with negative lymph nodes.

Adult↗
PubMed2000

Kinetic pathways of multiphase surfactant systems

Relaxation following a temperature quench of two- (L(alpha) and L3) and three-phase (L(alpha), L3, and L1) samples has been studied in a sodium dodecyl sulfate-octanol-brine system. In the three-phase case we have observed samples that are initially mainly of the sponge phase, with lamellar and micellar phases on the top and bottom of the sample, respectively. Upon decreasing the temperature, most of the volume of the sponge phase is replaced by the lamellar phase. During equilibration we have observed three regimes of behavior within the sponge phase: (i) first there is disruption in the L3 texture, then (ii) after the sponge phase homogenizes there is a L(alpha) nucleation regime; finally (iii), a bizarre plume connects the L(alpha) phase with the L1 phase. The relaxation of the two-phase sample proceeds instead in two stages. First L(alpha) drops nucleate in L3, forming an onion "gel" structure. Over time the L(alpha) structure compacts while equilibrating into a two-phase L(alpha)-L3 sample. We offer possible explanations for some of these observations in the context of a general theory for phase kinetics in systems with one fast composition variable and one slow.

Journal Article↗
PubMed1999

Arrays of multielement ultrasound applicators for interstitial hyperthermia.

Arrays of multielement ultrasound applicators for interstitial hyperthermia have been developed and tested both in vitro and in vivo. The system includes multielement applicators, a 64 channel RF driving unit, a power measuring unit, a 112 channel multisensor temperature measuring unit, and a water cooling unit. Ninety-five arrays of single-element and nine arrays of three-element ultrasound applicators were designed, built, and characterized by measuring transducer efficiency and ultrasound field distribution. Improved uniformity in the azimuthal direction was achieved by using multiple driving frequencies. In addition, production of ultrasound in a desired sector of the transducer was possible by selecting a suitable frequency. Both in vitro and in vivo experiments showed that 92% of monitored temperature points within the target volume of 30 mm x 30 mm x 35 mm achieved a therapeutic temperature rise (above 5 degrees C) when an array of five three-element applicators were used. These results indicated that the arrays of multielement ultrasound applicators have distinct advantages over present interstitial hyperthermia modalities in terms of the capability to control the temperature distribution with a large catheter spacing. As a conclusion, the feasibility of a practical arrays of multielement ultrasound applicators for interstitial hyperthermia was demonstrated.

Animals↗
PubMed1996

A primary intraosseous carcinoma of the anterior maxilla. Report of a new case.

The case of a primary intraosseous carcinoma occurring in the maxilla is presented. The classification; clinical, radiologic, and light microscopic features; and treatment are described. These rare lesions should be considered among the diagnostic possibilities when patients present with atypical cysts of the jaws.

Diagnosis, Differential↗
PubMed1996

Electromyographic activity during windsurfing on water.

Electromyographic activity and the electrocardiogram were recorded during windsurfing on the water in six subjects (three females and three males). 'Beating' and 'reaching' (both with continuous pumping), 'running' and 'uphauling' were performed in light to moderate winds. The physiological signals were transmitted to a shore base by radio telemetry and recorded with synchronized video and audio information of movement. Heart rates were similar for the beating, reaching and running activities within the individuals, but varied between individuals (means of 145 to 173 beats min-1), due to performance conditions and related muscle activity levels. During beating and reaching, the trapezius, flexor carpi ulnaris, extensor carpi radialis, biceps brachii and tibialis anterior were very active, with the gluteus maximus being particularly important in beating. Running involved less general muscle activity, though the role of the tibialis anterior increased. Differences in technique were identified between the subjects, notably in the order of muscle recruitment to participate in the activities.

Electromyography↗