Lung ventilation volumetry with same-breath acquisition of hyperpolarized gas and proton MRI.

The purpose of this work was to assess the reproducibility of percentage of ventilated lung volume (PV) measured from hyperpolarized (HP) (3)He and (1)H anatomical images acquired in the same breath-hold when compared with PV measured from (3)He and (1)H images from separate breath-holds. Volumetric (3)He ventilation and (1)H anatomical images of the same resolution were acquired during the same breath-hold. To assess reproducibility, this procedure was performed twice with a short gap between acquisitions. In addition, (1)H images were also acquired in a separate breath for comparison. PV ((3)He ventilated volume divided by (1)H total lung volume) was calculated using the single-breath-hold images (PV(single)) and the separate-breath-hold images (PV(separate)). Short-term reproducibility of PV measurement was assessed for both single- and separate-breath acquisitions. Dice similarity coefficients (DSCs) were calculated to quantify spatial overlap between (3)He and (1)H segmentations for the single- and separate-breath-hold acquisitions. The efficacy of using the separate-breath method combined with image registration was also assessed. The mean magnitude difference between the two sets of PV values (±standard deviation) was 1.49 ± 1.32% for PV(single) and 4.19 ± 4.10% for PV(separate), with a significant difference (p < 0.01). The mean magnitude difference between the two PV values for the registered separate-breath technique (PV(sep-registered)) was 2.27 ± 2.23%. Bland-Altman analysis showed that PV measured with single-breath acquisitions was more repeatable than PV measured with separate-breath acquisitions, regardless of image registration. DSC values were significantly greater (p < 0.01) for single-breath acquisition than for separate-breath acquisition. Acquisition of HP gas ventilation and (1)H anatomical images in a single breath-hold provides a more reproducible means of percentage lung ventilation volume measurement than the previously used separate-breath-hold scan approach, and reduces errors.

Mitogen-induced responses in lymphocytes from platypus, the Tasmanian devil and the eastern barred bandicoot.

OBJECTIVE: As the platypus (Ornithorhynchus anatinus), the Tasmanian devil (Sarcophilus harrisi) and the eastern barred bandicoot (Perameles gunni) are currently at risk of serious population decline or extinction from fatal diseases in Tasmania, the goal of the present study was to describe the normal immune response of these species to challenge using the lymphocyte proliferation assay, to give a solid basis for further studies. METHODS: For this preliminary study, we performed lymphocyte proliferation assays on peripheral blood mononuclear cells (PBMC) from the three species. We used the common mitogens phytohaemagglutinin (PHA), concanavalin A (ConA), lipopolysaccharide (LPS) and pokeweed mitogen (PWM). RESULTS: All three species recorded the highest stimulation index (SI) with the T-cell mitogens PHA and ConA. Tasmanian devils and bandicoots had greater responses than platypuses, although variability between individual animals was high. CONCLUSION: For the first time, we report the normal cellular response of the platypus, the Tasmanian devil and the eastern barred bandicoot to a range of commonly used mitogens.

Work stress and physical assault of nursing aides in rural nursing homes with and without dementia special care units.

PURPOSE: This study compared nursing aides (NAs) employed in rural nursing homes with and without dementia special care units (SCUs) on (1) exposure to and distress from disruptive behaviours exhibited by residents, (2) job strain and (3) physical assault. DESIGN AND METHODS: The data were drawn from a larger study conducted in Saskatchewan, Canada, in which all rural nursing homes of < or = 100 beds that had an SCU were matched to same-sized rural facilities with no SCU. Nursing aides (n = 355) completed a mailed survey questionnaire. RESULTS: Nursing aides employed in nursing homes with an SCU reported significantly less frequent exposure to disruptive behaviours (including aggressive and aversive behaviours) than NAs in non-SCU facilities, less distress when these behaviours were directed toward them, less exposure to aggressive behaviour during caregiving, lower job demands and lower job strain. There was a trend toward increased risk of being assaulted in the last year associated with being in a non-SCU facility. Having a permanent position, increased job strain, and feeling inadequately prepared for dementia care were significantly associated with higher risk of being assaulted. In the SCU facilities, NAs who worked more time on the SCU reported more assaults but less distress from disruptive behaviour, lower psychological job demands, lower job strain and greater work autonomy. IMPLICATIONS: Providing more dementia care training and reducing job demands and job strain may help to reduce work-related stress and physical assault of nursing aides employed in nursing homes.

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.

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.

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.

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.

Effect of anterior cruciate ligament graft tensioning direction, magnitude, and flexion angle on knee biomechanics.

The objective of this study was to determine the biomechanical effect of graft tensioning during reconstruction of the anterior cruciate ligament. We evaluated the magnitude of the tensioning force (22 or 67 N), the flexion angle at which the tension was applied (extension or 30 degrees of flexion), and the direction of application of the tensioning force (proximal, distal, or distal with a posterior force simultaneously applied to the tibia) on 10 fresh cadaveric knees. The anterior cruciate ligament was reconstructed using a bone-patellar tendon-bone graft. The graft was then temporarily fixed during the application of each of 12 combinations of tensioning variables listed above. After each fixation, graft force and joint motion were measured during anterior tibial loads. Tensioning direction and the flexion angle significantly affected graft force and joint motion, while the magnitude of the graft tensioning did not. Graft forces were greater when the tensioning was applied at 30 degrees of flexion. Compared with distal tensioning with and without posterior tibial force, graft forces with proximal tensioning were greater in extension and lower in flexion. The position of the tibia relative to the femur was posterior and externally rotated, compared with normal, for all combinations of tensioning variables in both unloaded and anterior load states.

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.

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.

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.

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.

Capacity building in rural health research: a Canadian perspective.

INTRODUCTION: The need to build capacity in rural health research is recognized in Canada. During its formative stage, the Canadian Rural Health Research Society (established in 2002), performed a nation-wide survey of the research teaching and training opportunities available to students interested in rural and remote health issues. Intended as a cross-sectional 'snapshot,' and to provide base-line data, the survey involved a comprehensive list of educational programs in health and science disciplines at all Canadian Universities offering graduate-level programs. The present project report gives an overview of the results, documenting the current strengths, but also the noticeable gaps that exist. METHODS: Data were collected via an Internet survey, developed according to Dillman's email survey design principles. Although multiple contacts are recommended, due to time constraints only two were made. The instrument included both open- and closed-ended questions designed to determine institutional commitments to rural health research training generally, as well as specific information about course offerings, infrastructure supports for students, financial assistance for studying specific topics, and future plans. Health was defined broadly and included a number of disciplines beyond those usually considered under the health rubric. Individuals in administrative positions for 462 programs in 24 distinct disciplines at 56 institutions were sent the survey. Responses were received from 120 programs at 40 universities. Due to budget constraints the instrument was not translated into French. Descriptive statistics were used to analyse the data, combined with a thematic analysis of written comments. Ethical approval was obtained from the Lakehead University before the study was conducted. RESULTS: Despite the fact that one-third of Canadians live in rural, remote and northern areas, there is a paucity of research that addresses rural health issues. Moreover, Canadian universities have very limited rural health offerings in their curricula. There are few formal courses available on rural health topics generally or rural health research specifically. Although students can take rural-related independent studies or reading courses, very few actually take advantage of the option. Of all disciplines, nursing faculty are most likely to pursue rural health research and to offer rural health courses. Moreover, nursing faculty most often indicate an intention to expand their rural health offerings. In the social sciences, geography and environmental science programs, relatively few students choose to study rural health. Similarly, in medicine, the number of students exploring rural health issues is small. There is some specific financial assistance available to students who are interested in rural health research and, as well, they have access to general pools of funding. CONCLUSION: The survey results demonstrate the limitations of current educational programs. However, they also indicate areas of potential growth and show widespread interest in increasing the offerings available at universities across Canada. The article concludes by giving an overview of the mandate and initiatives being taken by the new research society to augment training, and to enhance student participation. In addition, it notes the positive developments linked to a new Strategic Plan by the Canadian Institutes of Health Research (CIHR) to enhance rural health research in Canada.

Possible differences in pathogenicity between cane toad-, frog- and platypus-derived isolates of Mucor amphibiorum, and a platypus-derived isolate of Mucor circinelloides.

Platypuses (Ornithorhynchus anatinus) in the north of the island state of Tasmania, Australia, suffer from a serious disease called ulcerative mycosis, which is responsible for high morbidity and, presumably, mortality rates in areas where it occurs. The disease is caused by the dimorphic fungus Mucor amphibiorum, which is also found in Queensland, New South Wales and Victoria. However, it does not cause disease in platypuses in those states. It has been previously reported that a closely related fungus, Mucor circinelloides, may also be capable of causing this disease. This paper describes pathogenicity trials involving cane toads (Bufo marinus) as the experimental model. The toads were infected with either Tasmanian, platypus-derived M. amphibiorum, West Australian, frog-derived M. amphibiorum, Queensland cane-toad-derived M. amphibiorum or Tasmanian platypus-derived M. circinelloides. The Tasmanian isolates of M. amphibiorum were more likely to cause a serious, long-term infection than were Queensland or West Australian isolates, and (+) mating types caused a more serious infection than the (-) mating type. The isolate of M. circinelloides was incapable of infecting the toads, lending further weight to the theory that it represents an environmental contaminant. The results suggest that an endemic strain of M. amphibiorum has mutated and become pathogenic to platypuses. Alternatively, a pathogenic strain of M. amphibiorum may have been introduced into Tasmania, where it is infecting a naïve population.

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.

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.

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).