Biomechanical Relationships Between Manual Wheelchair Steering and the Position of the Human Body's Center of Gravity.

The purpose of this investigation was to analyze the impact of differential steering of a wheelchair with a pushrim on changes in the position of the body's center of gravity. The method assumed measuring the wheelchair trajectory and the body's center of gravity and determining the transverse relocation of the measured body's center of gravity in relation to a point on the wheelchair trajectory. Twenty-seven measurement tests which demonstrated various wheelchair trajectories were carried out within the investigation. The trajectories were 10 to 15 m long and involved moving forward (test 2), reversing (test 3), turning left (test 1) and right (test 4). The factor of deviation of the center of gravity of human body from the wheelchair trajectory was determined for selected characteristic turning maneuvers. The measured values ranged from 51 to 192 mm. The impact of the wheelchair trajectory on the position of the body's center of gravity was demonstrated as a result of this investigation. Consequently, a trajectory deviation factor for relocation of the human body weight on one side of the wheelchair has been demonstrated.

Systolic myocardial volume gain in dilated, hypertrophied and normal heart. CMR study.

AIM: To investigate changes in myocardial tissue volume during the cardiac cycle to verify the hypothesis of non-compressibility of the myocardium in healthy individuals (HI) as well as in patients with hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and aortic stenosis (AS). MATERIALS AND METHODS: The study group included 30 HI, and patients with HCM (n=110), DCM (n=89), and AS (n=78). Left ventricular (LV) function, end-diastolic, and end-systolic volumes were calculated based on cardiac magnetic resonance imaging (CMR) for all participants. RESULTS: End-systolic myocardial volumes were higher than end-diastolic in both controls (91.2±26.6 versus 85.1±24.3 ml, p<0.001) and in all patient groups: HCM (214.3±81.6 versus 176±64.2 ml, p<0.01), DCM (128.4±43.1 versus 115.4±42.9 ml, p<0.001) and AS (155.1±37.1 versus 129.4±34.6 ml, p<0.001). HCM and AS patients had significantly higher systolic volume gain than HI (21.5±8.3 versus 10.6±6.3%, p<0.01 and 18.3±5.7 versus 10.6±6.3% p=0.013, respectively). Conversely, DCM patients had lesser increases in myocardial systolic volume than HCM patients (11.2±4.8% versus 21.5±8.3, p=0.01) and AS patients (11.2±4.8% versus 18.3±5.7, p=0.02). No differences were found in systolic volume gain between AS and HCM patients (p=ns) or between DCM patients and HI (p=ns). CONCLUSION: End-systolic myocardial volume was significantly higher than end-diastolic volume in all subsets of patients. The systolic volume gain was greater in individuals with hypertrophy than in those without.

Cholesterol sulphate sulphohydrolase from human placenta microsomes--purification and properties of the dephosphorylated form of enzyme.

The procedure for purification of cholesterol sulphate sulphohydrolase (ChS-ase) from human placenta microsomes was elaborated. The highly purified enzyme preparation (specific activity 2000 nmol x min(-1) x mg protein(-1)) exhibited optimal activity at pH 9.0. The K(m) value was established to be 1.5+/-0.85 x 10(-5) M. The high molecular weight form (200 kDa) and the low molecular weight form (20 kDa) of the enzyme were separated. The interconversion of the high molecular weight variant into the low one occurs under the influence of dephosphorylation. Both forms exhibited typical Michaelis-Menten saturation kinetics. The effect of different compounds on the enzyme activity was tested.

Obstructed central venous catheters. Restoring function with a 12-hour infusion of low-dose urokinase.

Thrombotic obstruction frequently prohibits infusion through or withdrawal of blood from central venous catheters and can occur in conjunction with symptomatic thrombosis of the subclavian vein. Thirty catheters were radiographically proved to be obstructed by thrombus and had not responded to at least one instillation of 5000 units of urokinase. All catheters were treated with a 12-hour infusion of urokinase at the rate of 40,000 units/hour. The obstructing thrombus was either eliminated or reduced in size in all instances and full function was restored in all but one catheter. No bleeding complications were seen. Six patients with obstructed catheters also had symptoms of subclavian vein thrombosis. All patients with symptoms of subclavian vein obstruction became asymptomatic on anticoagulant therapy even though no attempt at dissolving the thrombus obstructing the subclavian vein was made. A 12-hour infusion of low doses of urokinase can safely salvage function of obstructed catheters that otherwise may require replacement. Patients with concomitant subclavian vein thrombosis become asymptomatic on anticoagulant therapy without need to dissolve the obstructing thrombus.

An alternative approach to discipline.

A role of the nurse manager is to promote a sense of personal responsibility, self-discipline, and personal commitment in each employee to achieve the objectives and goals of the organization. Positive, nonpunitive discipline creates a climate wherein the staff member willingly conforms to rules, regulations, and standards of conduct and works toward the organizational goals.

Translumbar inferior vena cava catheters: safety and efficacy in peripheral blood stem cell transplantation.

Most patients who need peripheral blood stem cell transplantation do not have peripheral venous access that would allow apheresis for stem cell collection. Subclavian apheresis catheters have an unacceptably high incidence of thrombosis-related access failure. A technique has been developed for translumbar placement of permanent, subcutaneously tunneled, silicone rubber apheresis catheters into the inferior vena cava, and 40 of these catheters have been placed in 36 patients for stem cell collection. Twenty-six catheters have been left in place for venous access during the transplantation procedure. These catheters had a very low rate (2.3%) of apheresis-related related complications. Access failure was attributed to thrombosis in 10 catheters (25%) and to mechanical complications in another 9 (22%), but access was regained in all but 4 of these cases. The catheters functioned well as venous access devices during transplantation, only rarely developing complications during that time. Venograms performed at the time of removal of 16 catheters showed no case of caval occlusion. A residual fibrin sheath was found around 14 catheters. There was no clinical or computed tomographic scan evidence of bleeding after placement or removal of the catheters. Percutaneously placed, translumbar inferior vena cava apheresis catheters provide a safe and effective route for the collection of peripheral blood stem cells for transplantation, and they can be left in place for venous access during transplantation.

Translumbar inferior vena cava catheters: experience with 58 catheters in peripheral stem cell collection and transplantation.

Most patients who need peripheral stem cell transplantation do not have peripheral venous access to allow apheresis for stem cell collection. Subclavian apheresis catheters have an unacceptably high incidence of thrombosis-related access failure. We have used a technique for translumbar insertion of permanent, subcutaneously tunnelled silicone rubber apheresis catheters into the inferior vena to place 58 catheters in 54 patients for stem cell collection. 37 catheters have been left in place for venous access during the transplantation procedures. These catheters had a very low rate of apheresis-related complications (3.6%). Access failure occurred due to thrombosis in 14 catheters (24%) and mechanical complications in 8 (14%) but these responded to standard therapy in all except 3 cases. Catheters functioned well as venous access devices during transplantation with only rare complications during this time. Withdrawal venograms at time of removal of 20 catheters showed a fibrin sheath in 17 cases but caval occlusion in none. There was no clinical or CT scan evidence of bleeding after placement or removal of the catheters. Percutaneously placed translumbar inferior vena cava apheresis catheters are an effective route for peripheral stem cell collection and can be left in place for venous access during transplantation.

Stage-dependent viability of vitrified rabbit embryos.

The aim of the work was to determine the susceptibility of rabbit embryos to vitrification at different developmental stages. The experiment was carried out on 676 embryos at 1-, 2- and 8-to 16-cell stages as well as the morula and blastocyst stages. As a vitrification medium, a mixture of 30% 1,2-propanediol + 30% glycerol (Solution I), or 35% 1,2-propanediol + 35% glycerol (Solution II), was used. The embryos were frozen in glass ampules placed in nitrogen vapour for 5 min before being plunged into liquid nitrogen. Dilution after rapid thawing was done in one step in a 1-M sucrose solution. After vitrification in Solution I, none of the 1- or 2-cell embryos survived, whereas the survival rate of 8-to 16-cell embryos, morula and blastocysts, was 23.0, 82.7 and 78.5%, respectively. After vitrification in Solution II, the survival rate of 1-, 2- and 8-to 16-cell embryos was 20.0, 43.8 and 92.9%, respectively. The proportion of live offspring on the Day 28 after transfer of 68 vitrified morula was 26.5% compared with 24.0% in the control group. Thus, the proposed vitrification procedures can be useful in the cryopreservation of rabbit embryos.