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Biomedical subjects

P Costigan

Publications and source records attributed to P Costigan.

11 recordsLinked to original sources
PubMed2000

Investigation of an outbreak of gastroenteritis caused by Norwalk-like virus, using solid phase immune electron microscopy.

In February 1993, 95 persons (47 patients and 48 staff members) were affected by an hospital outbreak of viral gastroenteritis. Using direct electron microscopy (EM) the causative agent was identified as a small round structured virus. This was confirmed as a Norwalk-like virus using solid phase immune electron microscopy (SPIEM). Of 94 stool samples examined, 12 (13%) samples containing small round structured viruses (SRSV) were SPIEM positive for Norwalk-like virus. A further 25 (27%) samples contained small round featureless virus (SRFV) identified by direct EM and were negative on SPIEM. The illness was characterized by preceding influenza-like symptoms in 76% of cases followed by vomiting (76%), diarrhoea (79%) and abdominal pain (79%). One fatality was recorded. The outbreak lasted for 15 days, with a peak incidence of new cases amongst patients and staff occurring on day 5. It was controlled through a combination of ward closures, patient cohorting, suspension of duties for affected staff and disinfection procedures. Difficulties were encountered in the education of staff and in the implementation of environmental control measures. Screening of hospital catering services and a case control study, carried out among affected staff members, failed to identify a foodborne source. Consumption of tap water in the hospital was commoner among affected staff members than among controls, but this did not reach significance (P = 0.1).

Aged↗
PubMed1999

Radiographic and non-invasive determination of the hip joint center location: effect on hip joint moments.

OBJECTIVE: To determine which of four non-invasive measures is most accurate in locating the hip joint center. BACKGROUND: The location of the joint centers must be accurately determined in three dimensions for calculation of the moments of force during gait. It is not known which of the several non-invasive methods available for location of the hip center is most accurate. DESIGN: Hip center location was determined using standardized X-rays and four non-invasive methods which utilized measured distances between bony landmarks in 10 healthy subjects. Hip moments during gait were obtained from optical tracking, force plate and anthropometric data. RESULTS: The most accurate non-invasive method of locating the hip center was by taking the midpoint of a line connecting the antero-superior iliac spine and the symphysis pubis and moving inferiorly 2 cm. Using this approach the hip center was located 0.7 cm medial and 0.8 cm superior to its true location determined using the standardized X-rays. The 95% confidence interval of the maximum error difference in moments measured between this method and the standardized X-rays ranged from -0.15 to 0.4 Nm/kg in the frontal plane, -0.03 to 0.07 Nm/kg in the sagittal plane and -0.05 to -0.03 Nm/kg in the transverse plane. CONCLUSIONS: Locating the hip center based on the distance between the antero-superior iliac spine and the symphysis pubis is a valid technique for estimating the hip center in routine gait analysis.

Aged↗
PubMed1999

Hip moments during level walking, stair climbing, and exercise in individuals aged 55 years or older.

BACKGROUND AND PURPOSE: Low bone mass of the proximal femur is a risk factor for hip fractures. Exercise has been shown to reduce bone loss in older individuals; however, the exercises most likely to influence bone mass of the proximal femur have not been identified. Net moments of force at the hip provide an indication of the mechanical load on the proximal femur. The purpose of this study was to examine various exercises to determine which exercises result in the greatest magnitude and rate of change in moments of force at the hip in older individuals. SUBJECTS AND METHODS: Walking and exercise patterns were analyzed for 30 subjects (17 men, 13 women) who were 55 years of age or older (X = 65.4, SD = 6.02, range = 55-75) and who had no identified musculoskeletal or neurological impairment. Kinematic and kinetic data were obtained with an optoelectronic system and a force platform. Results. Of the exercises investigated, only ascending stairs generated peak moments higher than those obtained during level walking and only in the transverse plane. Most of the exercises generated moments and rate of change in moments with magnitudes similar to or lower than those obtained during gait. CONCLUSION AND DISCUSSION: Level walking and exercises that generated moments with magnitudes comparable to or higher than those obtained during gait could be combined in an exercise program designed to maintain or increase bone mass at the hip.

Aged↗
PubMed1997

Axial lower-limb alignment: comparison of knee geometry in normal volunteers and osteoarthritis patients.

Osteoarthritis of the knee is associated with deformities of the lower limb and malalignment of the limb segments. Pathogenetic relationships between the two are poorly understood. Alignment was studied by standardized radiography in 167 symptomatic Canadian osteoarthritis patients, and compared with 119 healthy adult volunteers. In healthy adults overall alignment (hip-knee-ankle angle) was principally determined by distal femoral valgus (condylar hip angle) and proximal tibial-plateau varus (plateau-ankle angle): the angle between the joint surfaces (condylar plateau) was relatively constant. In osteoarthritis, disease-associated differences included condylar-plateau angles that were divergent: accentuated medial convergence in varus osteoarthritis and lateral convergence in valgus osteoarthritis. This was interpreted as change arising from focal loss of cartilage in the medial (varus osteoarthritis) or lateral (valgus osteoarthritis) compartments of the knee. The changes would contribute to increasing limb malalignment during disease progression. But differences of limb geometry also contributed to malalignment. These were the average trends: in varus osteoarthritis there was abnormal femoral geometry (lesser femoral condylar valgus), but tibial surface geometry was the same. In valgus osteoarthritis, the opposite was true: abnormal tibial geometry (lesser plateau varus), but normal femoral geometry. A possible explanation is that these abnormal knee geometries pre-exist and predispose to osteoarthritis, although it is not impossible that they (like condylar-plateau angle) change as disease progresses. Further approaches to population studies are discussed based on these findings, along with their implications for knee surgery.

Adult↗
PubMed1995

Local anesthesia for postoperative pain relief after foot surgery: a prospective clinical trial.

A prospective, randomized, controlled clinical trial was set up to test whether the addition of ankle block to general anesthesia was useful in providing postoperative pain relief following forefoot surgery. Forty feet (20 treatment, 20 control) were entered into the trial and all underwent bony operations on the first ray. Pain was assessed at fixed times following the operation using pain analog scales. Analgesic consumption and wound healing were also assessed. A significant difference was found between the pain scores in the two groups at the 6-hr stage, but there was no difference in any of the other assessments. It is concluded that ankle block is a useful addition to general anesthesia for this type of surgery.

Adolescent↗
PubMed1994

Elbow kinematics during sit-to-stand-to-sit of subjects with rheumatoid arthritis.

Independence in mobility is dependent on the ability to rise from a chair. Elbow kinematics of subjects with rheumatoid arthritis were compared to those of subjects with no known elbow pathology. Through a case study approach, four subjects with varying elbow pathology and symptoms, were compared with a control group of 10 subjects on four kinematic variables. Results indicated that whereas the overall movement pattern was similar between the two groups, a trend toward increased deviation occurred with increased elbow involvement (as measured using the Morrey Elbow Evaluation). The total time taken to complete the task increased and the maximum velocity decreased as scores on the Morrey Evaluation decreased. When the minimum flexion angle (maximum extension) used during the activity was compared with the minimum flexion angle available, the angle used was consistently 15 degrees to 20 degrees less than that available. This possible need for a residual range raises questions about the generally accepted belief that activities require between 30 degrees to 130 degrees of flexion and 100 degrees of rotation.

Adult↗
PubMed1978

Chronic methylmercurialism in the cat.

The mercury levels in 69 muscle samples from fish weighing from 0.3 to 200 kg caught in Moreton Bay, Queensland, in the latter half of 1976 ranged from less than 10 to 2,030 ng/g. Mercury levels in blood samples from 53 humans and 100 dogs in Brisbane almost all contained less than 10 ng/ml while the level in 162 cats sampled ranged from less than 10 to 329 ng/ml. Chronic methylmercurialism developed in 2 cats dosed daily with methylmercury, bound to cysteine, at the rate of 0.6 mg/kg body weight for 74 and 77 days respectively. Terminal clinical signs included anorexia, weight loss, knuckling over at the carpus and tarsus, hypermetria initially involving the forelegs and later the hindlegs, sluggish reflexes, paresis involving all limbs, persistent crying, apparent blindness, tonic and clonic convulsions and salivation. Pathological changes were confined to the nervous system and included degeneration of neurones and perivascular cuffing in the cerebrocortical grey matter, focal atrophy of the granular layer, focal spongiosus of the molecular layer and degeneration and loss of Purkinje cells in the cerebellum and demyelination in the fibre tracts of the dorsal funiculus, mainly the fasciculus cuneatus and in the lateral and ventral corticospinal tracts. Terminal blood methylmercury levels were in excess of 18 microgram/ml, while brain methylmercury levels ranged from 21.0 to 28.4 microgram/g. The liver and kidney contained the highest total levels of mercury of 50 to 80 microgram/g, of which 23 to 37% was inorganic.

Animals↗
PubMed1977

Some toxicity aspects of dichlorvos flea collars in cats.

The effects of the application of a single dichlorvos flea collar containing 500 mg of the insecticide were observed in 23 growing cats for periods of from 1 to 15 weeks. No overt signs of toxicity occurred and weight gain in young growing animals was not significantly affected. Whole blood cholinesterase was reduced within the first week of application of the collar and remained below pretreatment levels for 5 to 8 weeks before returning to normal presumably as the insecticide concentration in the resin was progressively reduced. Signs of systemic organophosphate toxicity did occur within 1 week of the application of three collars to each of two cats kept in the same cage. This suggested that the likelihood of toxicity occurring in cats following the use of dichlorvos flea collars depended mainly on the degree of exposure to the insecticide. Considering recent reports in the literature it was proposed that the environmental conditions of temperature (11 degrees to 23 degrees C) and relative humidity (50 to 65%) under which the experiments were carried out would have promoted a relatively low atmospheric concentration of dichlorvos in the near environment of the test animals and hence generally prevented occurrence of clinical signs. Under most conditions of keeping domestic cats in Australia the use of a single dischlorvos flea collar should therefore be without any untoward effect although some initial and transient inhibition of whole blood and nervous tissue cholinesterases would be expected.

Animals↗