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Biomedical subjects

J G Reid

Publications and source records attributed to J G Reid.

At least 19 recordsLinked to original sources
PubMed1992

Comparison of three noninvasive methods for measuring scoliosis.

The premise behind most noninvasive techniques for the measurement of scoliotic conditions of the spine is that the lateral distortion of the spine relates directly to transverse rib cage deformity within the transverse plane. The focus of this study was to examine this assumption by comparing different noninvasive methods for the assessment of scoliotic curves. The three techniques examined were (1) use of the Scoliometer (SCOL), (2) use of the back-contour device (BCD), and (3) use of moiré topographic imaging (MTI). Fourteen subjects (10 female, 4 male) with idiopathic adolescent scoliosis were measured. Posterior-anterior radiographs were obtained for the clinical assessment of all subjects and were subsequently used to determine Cobb angles. Significant correlations between axial trunk rotation and Cobb-angle measurements were observed in the thoracic region (MTI, r = .80, df = 10, P less than .005; BCD, r = .70, df = 10, P less than .025; SCOL, r = .59, df = 10, P less than .025) but were not found within the lumbar region (MTI, r = .42; BCD, r = .17; SCOL, r = .20). Factors other than trunk deformity, such as the posture assumed by the subject during measurement, may have influenced axial trunk rotation. Hence, the techniques appear to provide valid estimations of lateral curvature of the spine in the thoracic region of the trunk but not the lumbar region. The results suggest that the measurement techniques cannot be used interchangeably in clinical recording.

Adolescent↗
PubMed1991

Morphometry of the human thigh muscles. A comparison between anatomical sections and computer tomographic and magnetic resonance images.

The present study examined the relative accuracy and precision of MR and CT procedures for determining the CSA of individual muscles from the human thigh. Serial AN, CT and MR cross-sections were obtained from three cadaveric lower limbs. The MR measurements provided accurate and precise values for the CSAs of most thigh muscles, generally within +/- 7.5% of the AN standard. In contrast, CT tended systematically to overestimate the AN CSA by 10-20%. Retest procedures indicated that highly reliable measurements could be obtained from both MR and CT images. However, subjective interpretations of boundaries between closely apposed muscle bellies, particularly for muscles with more than one head, were necessary for resolving entities in the imaging records and this decreased the relative accuracy of MR and CT measures. Interestingly, MR records demonstrated an incomplete septum between vastus lateralis and vastus intermedius more prominently than AN cross-sections. The novel cross-validation procedures used in this study also highlighted several system-based errors in the MR records that, if undetected and left uncorrected, would have seriously biased the morphometric data obtained with this technique. In general, MR provides high resolution images of the human thigh muscles which may be used to obtain valid measures of the CSA of these structures.

Cadaver↗
PubMed1989

Method for determining vertebral body positions in the sagittal plane using skin markers.

A method by which the location of vertebral bodies can be estimated from the external profile of the spine in the sagittal plane is described. The technique involves a normalization of the curve from T1 to L5 and approximation using a cubic spline. Mapping functions are developed that enable the transformation of a skin profile to a vertebral centroid curve. Data were obtained for 13 subjects between the ages of 13 and 17 who had undergone lateral spinal radiographs with radiopaque skin markers over the vertebral spinal processes. Results suggested that vertebral body centroids could be estimated from the skin profile to a precision having a standard error of the estimate of 0.4 cm. This was improved to 0.2 cm if the lumbar curve were considered separately.

Humans↗
PubMed1988

Biomechanical considerations of the menisci of the knee.

The menisci of the knee are important structures for maintaining a healthy joint since they absorb shock and prevent rotatory instability. The shapes of the menisci and the orientations of their collagen fibres are naturally suited for bearing weight of the joint. Their shape also allows the tibial plateau contact area to be three times greater, thereby decreasing the stress by up to seven times. The medial and lateral menisci are able to move to different extents as a result of the variable laxities of the adjoining ligaments. Often a meniscus becomes injured and must be surgically removed by either a partial or total meniscectomy. Many meniscal injuries occur during sports activities and are caused predominantly by a twisting motion. A meniscectomy has been shown to have detrimental effects including increased joint laxity, osteoarthritis, and other structural changes. Approximately 25% of those who have had a total meniscectomy must stop or restrict their sports activities.

Arthroscopy↗
PubMed1987

The pharmacokinetics of ketoconazole after chronic administration in adults.

We have studied the pharmacokinetics of the anti-mycotic ketoconazole in seven patients who took it for 1-6 months at a dose of 200 mg daily. The mean elimination half-life of the drug was 3.3 h, and although the ketoconazole was given only once daily, a satisfactory clinical response was obtained in all seven individuals. Only a small fraction of the absorbed drug (mean 0.22%) was excreted unchanged in the urine, suggesting almost complete metabolism. Our results support the concept that anti-mycotic activity in the tissues continues after the plasma drug concentration has fallen below a critical level. Our results also support the concept of a change in pharmacokinetics with chronic dosing.

Adult↗
PubMed1987

Prediction of trunk muscle areas and moment arms by use of anthropometric measures.

The prediction of five internal muscle variables extracted from computed tomography scans was attempted using 27 anthropometric variables. Stable regression equations are presented for the prediction of the cross-sectional area of the rectus abdominis, psoas, and erector spinae, as well as for the moment arm of the erector spinae. No stable regression equation was found for the prediction of the moment arm of the rectus abdominis, and the results indicated that the method was group dependent. These findings have implications for human modeling studies that use estimated parameters for the internal muscle variables.

Abdominal Muscles↗
PubMed1987

Trunk muscle balance and muscular force.

An investigation of the absolute strength of the human muscle was carried out on the in vivo erector spinae muscle using magnetic resonance tomography coupled with dynamic muscular testing. The absolute strength of the erector spinae was calculated to be 48 N/cm2. The area of the rectus abdominis was 15.1 cm2, and the area of the erector spinae was 54.5 cm2. The internal moment arm for the rectus abdominis and erector spinae muscles was 7.04 and 5.64 cm, respectively. The static force measures showed the trunk extensor moment to be only 30% greater than the flexor moment. The difference is discussed in terms of the absolute strength of muscle, and other anatomic factors.

Abdominal Muscles↗
PubMed1984

Time course and prognosis of local recurrence following primary radiation therapy for early breast cancer.

The frequency, time course, and prognosis of local recurrence following primary radiation therapy in 152 patients with early breast cancer treated before 1967 were examined. Local recurrence occurred at a constant rate over the first 14 years after treatment. The crude 15-year local recurrence rate was 22%. Of the 30 patients who developed an isolated local recurrence and underwent definitive secondary surgery, the 10-year freedom from distant relapse rate was 50%. These results indicate that breast cancer patients treated by primary radiation therapy require long-term follow-up to detect curable local recurrences.

Breast Neoplasms↗
PubMed1984

Physical properties of the human trunk as determined by computed tomography.

The purpose of this study was to determine the center of mass of the trunk in living subjects by using computed tomography (CT), thus providing more accurate data to aid scientists in their effort to describe human motion quantitatively. This advanced x-ray was used to analyze the trunk segment of four subjects, two men and two women, ranging in age from 46 to 68 years. Scans were taken at 1 cm intervals, from the level of the superior surface of the pubic symphysis to the suprasternal notch. Data were processed by an on-line computer, with the object represented on photographic film as a gradient image of gray levels. The intensity of the gray scale in each cross-sectional scan corresponded to a particular density of human body tissue. The computer program was capable of interpreting this information, thereby providing values for the center of mass, tissue density, segmental mass, and volume. The study's conclusions are based on data obtained from living subjects which may be representative of the general adult population. We found that the mean center of mass of the trunk segment was 49.35% of the total length as measured from the line joining the greater trochanters across the superior surface of the pubic symphysis to the suprasternal notch. Furthermore, the segmental mass of the trunk segment was found to be 52.58% of total body weight. These data differ from trunk cadaveric studies already published.

Aged↗
PubMed1983

Ovarian irradiation and prednisone following surgery and radiotherapy for carcinoma of the breast.

Following mastectomy, patients with operable breast cancer underwent postoperative irradiation of the chest wall and regional lymph nodes. They were then assigned at random to receive no further therapy, ovarian irradiation (2000 rad in five days) or ovarian irradiation in the same dosage plus prednisone, 7.5 mg daily. A total of 705 patients received the randomly assigned treatment and were followed for up to 15 years. In premenopausal patients who received ovarian irradiation, the recurrence of breast cancer was delayed and survival prolonged, but not significantly. In premenopausal women aged 45 years or more, ovarian irradiation plus prednisone therapy significantly delayed the recurrence of breast cancer (p = 0.04) and prolonged survival (p = 0.02). No value was demonstrated for ovarian irradiation with or without prednisone therapy in postmenopausal patients.

Adult↗
PubMed1983

A force-torque analysis of the kip on the horizontal bar.

The purpose of this study was to determine the forces and torques on the horizontal bar during the kip. Six Canadian male gymnasts were filmed using a high speed camera during a short gymnastic routine including a kip on a horizontal bar which was wired with strain and torque gauges. During the performance, voltage outputs representing force and torque were amplified and recorded on tape. The force-torque data were then subjected to computer analysis. Maximum forces and torques were determined and force-angle plots were normalized by dividing force by body weight. The range of maximum forces was 1344-1563 N with a mean of 1444 N, which was approximately 2.3 times the body weight. The maximum forces were obtained when the center of mass was almost directly below the bar with the timing of maximum force application ranging +/- 0.1 sec from either side of 180 degrees. Maximum torques ranged from 10.0-21.0 N X m (Mean 17.3 N X m).

Adult↗
PubMed1982

Breast cancer: a 21 year experience with conservative surgery and radiation.

Evidence is presented from a study of 680 patients followed over a period of 21 years that conservative treatment of breast cancer by local excision of the primary tumor followed by breast irradiation yields results equivalent to the traditional radical approach, with the added benefit of an excellent cosmetic result and improved quality of life. The relative survivals were 8.3% at 5 years and 71% at 10 years. There was no difference in survival when radiation was given. Breast irradiation significantly reduced relapse in the breast, but axillary irradiation did not influence relapse at this site. Relapse in the breast alone was not detrimental to survival if treated appropriately. Axillary relapse indicated a much poorer prognosis as might be expected.

Brain Neoplasms↗
PubMed1980

Environmental dermatitis: changing patterns.

Patch tests in 1000 cases of contact allergic dermatitis observed between 1972 and 1978 are recorded in detail, and compared in general with patch tests in a previously recorded 1000 cases of contact allergic dermatitis between 1964 adn 1972. The routine use, since 1974, of patch tests as advised by the International Contact Dermatitis Research Group has increased the detection of dermatitis caused by nickel, paraphenylene-diamine and related dyes, formaldehyde and perfumes (balsam of Peru), which indicates that aimed patch tests alone may be inadequate. The number of cases of dermatitis caused by antifungal agents and topical antihistamines decreased after Commonwealth and State legislation prohibiting their use was passed.

Allergens↗
PubMed1979

Ovarian carcinoma: improved survival following abdominopelvic irradiation in patients with a completed pelvic operation.

A prospective, stratified, randomized study of 190 postoperative ovarian patients with Stages IB, II, and III (asymptomatic) presentations is reported. The median time of follow-up was 52 months. Patients in whom bilateral salpingo-oophorectomy and hysterectomy (BSOH) could not be completed because of extensive pelvic tumor had a poor prognosis which did not differ for any of the therapied tested. When BSOH was completed, pelvic plus abdominopelvic irradiation (P + AB) with no diaphragmatic shielding significnatly improved patient survival rate and long-term control of occult upper abdominal disease in approximately 25% more patients than pelvic irradiation alone or followed by adjuvant daily chlorambucil therapy. The effectiveness of P + AB in BSOH-completed patients was independent of stage or tumor grade and was most clearly appreciated in patients with all gross tumor removed. Chlorambucil added to pelvic irradiation delayed the time to treatment failure without reducing the number of treatment failures.

Abdomen↗
PubMed1979

Ovarian irradiation and prednisone therapy following surgery and radiotherapy for carcinoma of the breast.

Following mastectomy, patients with operable breast cancer underwent postoperative irradiation of the chest wall and regional lymph nodes. They were then assigned at random to receive no further therapy, ovarian irradiation (2000 rads in 5 days) or ovarian irradiation in the same dosage plus prednisone, 7.5 mg daily. A total of 705 patients received the randomly assigned treatment and were followed for up to 10 years. In premenopausal patients who received ovarian irradiation the recurrence of breast cancer was delayed and survival prolonged, but not significantly. In premenopausal women aged 45 years or more ovarian irradiation plus prednisone therapy significantly delayed the recurrence of breast cancer (P = 0.02) and prolonged survival (P = 0.02); the survival expectancy of these patients was similar to that of the general population of the same age from the third year after the cancer operation. No value was demonstrated for ovarian irradiation with or without prednisone therapy in postmenopausal patients.

Adult↗