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Biomedical subjects

N J Stewart

Publications and source records attributed to N J Stewart.

At least 19 recordsLinked to original sources
PubMed2002

Accumulation of persistent organic pollutants in Tasmanian platypus (Ornithorhynchus anatinus).

Tailfat samples were collected from 56 platypuses, 38 male and 18 female in Tasmania. No statistically significant, nor apparent, differences between the sexes were found for tailfat lipid levels and DDT and its metabolites. Lindane and PCB concentrations in tailfat lipid. Apparently--but not statistically--significantly different levels of DDT and its metabolites. Lindane and PCB concentrations were found in animals from different geographic regions of the State. Higher concentrations of DDT and its metabolites and Lindane were related to the intensity of agricultural activity and elevated PCB levels were mainly found in animals from zones with industrial and hydroelectric developments.

Adipose Tissue↗
PubMed1999

The physical environment of special care units: needs of residents with dementia from the perspective of staff and family caregivers.

To manage the care of increasing numbers of residents with dementia, many long-term care facilities have created special care units (SCUs) designed to meet the unique needs of this group. This article describes results of the qualitative component of a larger research project examining environment-behavior relationships in dementia care settings. Eighteen indepth interviews were conducted with 9 staff and 9 family members of SCU residents. Thematic analysis was conducted using grounded theory techniques. Participants described residents' needs in relation to both the physical and social environments. This article focuses on the five areas of need identified by participants in relation to the physical environment: safety, homelike setting, optimal stimulation, cues, and options for privacy and social interaction.

Aged↗
PubMed1999

Caregiver distress. Related to disruptive behaviors on special care units versus traditional long-term care units.

The link between staff stress and exposure to disruptive behaviors is an important issue in long-term care settings. This study compared the perceptions of two groups of formal caregivers (staff) regarding their distress from the behaviors of residents in their care. Staff on special care units for dementia were less distressed with disruptive behaviors than comparable staff on traditional units, although they reported higher exposure to these behaviors. These results were related to different perceptions of intent to harm and expectations of physical aggression as "part of the job." Implications for nursing include education and support for staff to enhance the quality of life for residents and staff on units where disruptive behaviors occur.

Adolescent↗
PubMed1999

Isolation of Mucor circinelloides from a case of ulcerative mycosis of platypus (Ornithorhynchus anatinus), and a comparison of the response of Mucor circinelloides and Mucor amphibiorum to different culture temperatures.

The fungus Mucor circinelloides was isolated from a platypus (Ornithorhynchus anatinus) suffering from ulcerative mycosis. On horse blood agar at 20, 25 and 30 degrees C, the fungus formed sphaerule-like bodies, a morphology previously associated with Mucor amphibiorum, the species thought to be responsible for the disease in platypus. A biopsy taken from the ulcer was fixed, cut and stained. The sections were compared with sections taken from other platypuses suffering from ulcerative mycosis, and from which M. amphibiorum had been isolated. There were no discernible differences between the sphaerule-like bodies found in any of the sections. The presence of sphaerule-like bodies in tissues of ulcerated animals can, therefore, probably no longer be relied upon as a definitive method for the diagnosis of M. amphibiorum infection. It is possible that M. circinelloides is either a primary or a secondary pathogen of platypuses, and further work is required to resolve this point. The isolate of M. circinelloides grew at temperatures up to 38 degrees C, with an optimum temperature for growth of 30 degrees C. Of six isolates of M. amphibiorum derived from both platypus and amphibians, two grew well at 38 degrees C. The growth of one of these isolates at elevated temperatures may be explained by the hot climate of the area in Queensland in which it was found. All of the isolates tested had maximum temperatures for growth in excess of the body temperature of platypuses (32 degrees C).

Animal Diseases↗
PubMed1998

Disease conditions and subclinical infections of the platypus (Ornithorhynchus anatinus).

Before the arrival of European settlers in Australia, the platypus, Ornithorhynchus anatinus, probably suffered from little disease. Among other things, European settlement has involved substantial environmental perturbation, introduction of large predators, introduction of motor vehicles and translocation of potential pathogens. As a result, platypuses are now killed by motor vehicles, dogs, foxes and discarded plastic litter. Information programmes targeting appropriate segments of the public would help reduce these unnecessary deaths. The enigmatic disease, ulcerative mycosis, caused by Mucor amphibiorum, has been the subject of scientific investigation in Tasmania for the past 15 years. The apparent recent acceleration in its spread has sounded a warning and more intensive investigation is warranted. The possibility that this pathogen has been translocated from subtropical to temperate Tasmania, Australia, with green free frogs in banana shipments further emphasizes the role of humans in threatening the welfare of the platypus. Recommendations are made in relation to appropriate measures that could be taken to ameliorate disease and trauma in this species.

Animal Diseases↗
PubMed1998

Bilateral emphysematous pyelonephritis.

In any diabetic patient being diagnosed or treated for pyelonephritis, it is important to exclude the diagnosis of emphysematous pyelonephritis, which carries a high mortality rate. The authors present an illustrative case of emphysematous pyelonephritis treated with antibiotics and emergency nephrectomy. The signs, symptoms, pathophysiology, diagnosis, and treatment of emphysematous pyelonephritis are discussed.

Abscess↗
PubMed1997

Differences in patellar tracking and knee kinematics among three different total knee designs.

Patellar complications are the primary reason for reoperation of the current condylar type designs. The aim of this study was to compare patellar tracking of various knee implant designs: Genesis II NexGen, and the P.F.C. Sigma Modular Knee System regarding trochlear groove center curvature. Nine unembalmed whole cadaveric lower extremities were used. The quadriceps and hamstrings were dissected into their individual muscles and loads were applied onto the muscles proximally based on the cross sectional area of the muscles. The three-dimensional kinematics of the patellofemoral and tibiofemoral joint of the intact knee were measured using a 3Space tracking system. Three implants (one from each company) were implanted onto the same cadaveric knee in random order consecutively. This was done to ensure consistency of the soft tissue constraints in influencing the amount of patellar tracking. Patellar rotation, patellar tilting, patellar lateral shift and patellar displacement in relation to groove center were measured. There was no significant difference between the intact knee and the various implants regarding patellar rotation and lateral shift. However, all three prosthetic designs showed a significant degree of lateral tilting when compared with the intact knee. At 60 degrees knee flexion, the normal patella was tilted laterally to 0.44 degree +/- 2.15 degrees as compared with the Genesis II patella at 4.75 degrees +/- 4.81 degrees, the NexGen patella at 4.85 degrees +/- 4.81 degrees, and the P.F.C. Sigma patella at 4.89 degrees +/- 3.79 degrees lateral tilt. There was no difference between the intact knee compared with the resurfaced patella in patellar displacement in relation to the groove center. This study suggests the relatively similar kinematic behavior between the implant designs as compared with the intact knees. However, additional modification of implant geometry may be required to help decrease the amount of patellar tilt.

Arthroplasty, Replacement, Knee↗
PubMed1995

Lymphangiosarcoma following mastectomy.

This study reviews 16 cases of lymphangiosarcoma of the upper extremity after mastectomy for breast cancer (Stewart-Treves syndrome) was done at the author's institution from 1970 to 1992. Lymphangiosarcoma was diagnosed an average of 10.6 years (range, 5.6-18 years) after the diagnosis of breast cancer. Presenting signs included a bruise (6 patients); increased swelling (4); a red, raised lesion (2); a palpable mass (2); a blister appearance (1); and a non-healing eschar with continual bleeding (1). After biopsy, surgical treatment included forequarter amputation (8 patients), wide excision with grafting (5), and above-elbow amputation (1). Local recurrence of the lymphangiosarcoma occurred on the chest wall in 11 of the 16 patients after an average of 10.9 months. Metastasis occurred in 11 patients. (Metastasis occurred in 1 patient without local recurrence, and 1 patient with locally recurrent lymphangiosarcoma died of breast cancer before evidence of metastatic lymphangiosarcoma.) There are 2 long-term survivors who have lived 9.3 and 6 years, respectively, since the operation. One had been treated with a forequarter amputation and the other with wide excision. Early recognition and surgical treatment seem to offer the only chance for long-term survival.

Adult↗
PubMed1994

Load affects remodeling of transplanted, autogenous bone-patellar tendon-bone segments in a rabbit model.

The question of whether or not load affects the remodeling of a transplanted autogenous free graft was addressed by removal of the patella-patellar tendon-tibial tubercle complex from the right knees of 15 New Zealand White rabbits. The tubercle was split, and the tendon was divided with each half trimmed to an equal width. The autograft complex was transplanted into a subcutaneous tunnel on the back of the rabbit. Controlled cyclic loads were applied via transcutaneous sutures to half of the graft, while the other half remained unloaded. The mechanical stiffness and strength and the cell density of loaded and unloaded halves of the autograft were measured in nine animals at 3 weeks and in six animals at 6 weeks. Five autografts from four additional rabbits served as unimplanted controls. An analysis of variance showed that the loaded portions of the autografts had a significantly higher failure strength (mean of 90%) and were significantly stiffer (mean of 62%) than the unloaded halves at 3 and 6 weeks. Failure strength was significantly greater (mean of 90%) at 3 weeks than at 6 weeks. The autografts were less stiff and had a lower failure strength than the unimplanted controls, with the greatest difference occurring in the unloaded segments at 6 weeks. Histology revealed that both loaded and unloaded segments demonstrated an increase in cellularity at 6 weeks compared with 3 weeks. This report introduces a model for the study of the effect of load on soft-tissue grafts and demonstrates that loading affects the remodeling process of a transferred autograft.

Animals↗
PubMed1994

Movement therapy with depressed inpatients: a randomized multiple single case design.

The relative lack of research on movement therapy in inpatient versus outpatient settings stems from the difficulty of conducting an interpretable study in clinical situations where multiple treatments exist. To control for the multiple treatment confound, this study used a randomized single-case experimental design with 12 replications. Results indicated that the movement therapy, which was designed to target the syndrome of a major depressive episode had a positive effect on mood across experiments (p < .001). From a clinical perspective, these results support the use of a movement program as adjunctive treatment, and challenge the view that movement is recreation but not therapy.

Adult↗
PubMed1994

Predictors of participation in a peer-led exercise program for senior women.

This study explored variables selected using the Interaction Model of Client Health Behavior (Cox, 1982) and their relationship to exercise group participation in seniors. Seventy-five women were surveyed from from two similar senior apartment buildings. Subjects' ages ranged from 65 to 88 years (M = 75.91, SD = 6.12). Discriminant function analysis was used to test the relationship of seven demographic and motivational variables to choice of exercise group participation. As hypothesized, significant predictors for all the women in both buildings were: a measure of competence, education, number of medications, building, and age. Two variables, income and marital status, did not emerge as significant predictors. Women more likely to attend an exercise group had greater competence in health matters, higher education, a lower number of medications, were living in building B, and were lower in age. Nurses who facilitate exercise groups for seniors in the community should be aware of the impact these variables could have on attendance.

Aged↗
PubMed1993

Maintenance of set force in anterior cruciate ligament grafts.

This study was undertaken to determine how accurately total graft force and load-sharing between graft segments could be set and maintained during augmented anterior cruciate ligament (ACL) reconstruction in the goat knee. Special procedures were developed to reduce the effect of tissue creep and to overcome difficulties in the setting of graft force. Five knees from goat cadavers were reconstructed using a bone-tendon-bone graft (PT) and a synthetic augmentation device (LAD). Prescribed levels of total graft force and load-sharing between the autograft and LAD were set under a standardized external joint load. Immediately after fixation, the set force declined an average of 9 and 3% in the LAD and PT, respectively. After three subsequent exercise sequences, the set forces fell from their initial level by an average of 25% for the LAD and 28% for the PT. An analysis of variance did not show the loss of force with exercise to be statistically significant. We conclude from this in vitro study that our method can be used to set forces in an ACL reconstruction with reasonable maintenance of load-sharing but that losses of approximately 30% of total graft force after exercise of the reconstructed joint are to be expected.

Animals↗
PubMed1992

A theoretical model of the knee and ACL: theory and experimental verification.

A three-dimensional mathematical model of the human knee joint was developed to examine the role of single ligaments, such as an anterior cruciate ligament (ACL) graft in ACL reconstruction, on joint motion and tissue forces. The model is linear and valid for small motions about an equilibrium position. The knee joint is modeled as two rigid bodies (the femur and the tibia) interconnected by deformable structures, including the ACL or ACL graft, the cartilage layer, and the remainder of the knee tissues (modeled as a single element). The model was demonstrated for the equilibrium condition of the knee in extension with an anterior tibial force, causing anterior drawer and hyperextension. The knee stiffness matrix for this condition was measured for a human right knee in vitro. Predicted model response was compared with experimental observations. Qualitative agreement was found between model and experiment, validating the model and its assumptions. The model was then used to predict the change in graft and cartilage forces and joint motion of the knee due to an increment of load in the normal joint both after ACL removal and with various altered states simulating ACL reconstructions. Results illustrate the interdependence between loads in the ACL graft, other knee structures, and contact force. Stiffer grafts and smaller maximum unloaded length of the ligament lead to higher graft and contact forces. Changes in cartilage stiffness alter load sharing between ACL graft and other joint tissues.

Anterior Cruciate Ligament↗
PubMed1991

Quantitation of the alternate movement rate in normal and diabetic subjects.

Functional abnormalities of alternate movement rate (AMR) of finger and foot tapping were quantitated in 162 patients with diabetic neuropathy and 30 control subjects using a simple electronic device. The quantitative AMR (QAMR) averaged 29.5 +/- 3.0 for finger tapping and 20.4 +/- 3.7 for foot tapping in controls, and 27.5 +/- 4.8 (P less than 0.05) and 17.0 +/- 5.6 (P less than 0.005) for finger and foot, respectively, in diabetic patients. Fifty-one patients had abnormal QAMR in the finger and 79 in the foot. The QAMR values correlated with the results of nerve conduction studies of patients. Testing for abnormalities of AMR is a useful addition to the testing of dysfunction secondary to diabetic neuropathy. It provides quantitation of a common, subject-initiated, functional task more accurately than possible by clinical observation.

Adult↗
PubMed1991

Effects of laminin on functional reinnervation of target organs by regenerating axons.

Reinnervation of sweat glands, skeletal muscle and skin was studied in the mouse paw after section of the sciatic nerve and repair by entubulation with collagen conduits, with and without a coating of laminin. After operation, sweat glands activated by pilocarpine reappeared at 32 days and increased in number to 67% of control counts. Muscle action potentials (during sciatic nerve stimulation) were recorded from the interosseus muscle at 39 days. The potential amplitudes increased to 30% of controls. The first withdrawal response from pin prick to the paw was observed at about 34 days, the response score increasing to 66% of control. There were no significant differences at any test interval between the control group and the group with laminin added.

Animals↗