Trans-tibial amputee gait adaptations as a result of prosthetic inertial manipulation.

PURPOSE: To establish through gait analysis how changing the mass at the distal end of an in-house, custom-made trans-tibial dynamic elastic response prosthetic limb altered selected gait variables. Including; walking velocity, cadence, single support and hip power for a single amputee. METHOD: A before-after single-subject research design was used with two interventions. A 3-dimensional gait analysis was conducted to analyse the effect on selected gait variables. The mass and moment of inertia of the prosthesis were altered by inserting wedges of different materials. RESULTS: Altering the mass had little effect on the cadence, single support or the velocity. Both the affected and intact limb hip pull-off power at terminal stance was increased, although the effect was greater for the affected limb than for the intact limb. The affected limb hip power at initial contact did not alter in a manner directly related to the mass. CONCLUSIONS: Altering the mass had an inconsistent effect on the gait parameters tested. The subject volunteered that he preferred the prosthesis of the middle mass.

The effect of changing the inertia of a trans-tibial dynamic elastic response prosthesis on the kinematics and ground reaction force patterns.

The aim of this study was to assess, by means of gait analysis, the effect on the gait of a trans-tibial amputee of altering the mass and the moment of inertia of a dynamic elastic response prosthesis. One male amputee was analysed for four to five walking trials at normal and fast cadences, using the VICON system of motion analysis and an AMTI force plate. The kinematic variables of cadence, swing time, single support time and joint angles for the knee and hip on the affected and intact sides were analysed. The ground reaction force was also analysed. The sample size was limited to one as an example to indicate the changes which are possible through simply changing the inertial characteristics. Descriptive statistics are used to demonstrate these changes. Three mass conditions for the prosthesis were analysed m1: 1080g; m2: 1080 + 530g; m3: 1080 + 1460g. The m1 condition is the mass of the prosthesis with no added weight while m2 and m3 were attachments of the same geometrical shape but were made from different materials. It was felt that the large mass range would highlight biomechanical adjustments as a result of its alteration. The effect on selected temporal characteristics were that as the speed increased the cadence changed and the affected side single support times as a percentage of the gait cycle were altered. The effect on the joint angles was also apparent at the hip and knee of both sides. The ground reaction force patterns were similar for all three mass conditions, though the impact peak which was evident in the intact limb was missing, indicating a shock absorbing property in the prosthesis. Clearly, changing the mass and moment of inertia has an effect on the kinematic variables of gait and should be considered when designing a prosthesis.

Pasteurella multocida meningitis in a two-day old neonate.

A normal full-term baby boy, born by vaginal delivery, became ill on day 2 with fever and failure to feed. CSF examination revealed 260 x 10(6)/l leucocytes, mainly mononuclears, protein 2 g/l and glucose zero. Pasteurella multocida was isolated in pure culture from the baby's CSF, blood and umbilicus and from the mother's vagina. The baby was treated with i.v. penicillin for 7 weeks. Progress was complicated by mild hydrocephalus, which resolved, and prolonged low grade fever. Recovery was complete, without neurological sequelae. This case illustrates that P. multocida can infect the vagina where it presents a hazard to a newborn infant delivered vaginally. Early diagnosis is critical, intravenous high dose penicillin being the treatment of choice.

Hemodynamic and metabolic basis of impaired exercise tolerance in patients with severe left ventricular dysfunction.

Hemodynamic and metabolic changes were measured at rest and during exercise in 23 patients with chronic heart failure and in 6 control subjects. Exercise was limited by leg fatigue in both groups and capacity was 40% lower in the patients with failure. At rest, comparing patients with control subjects, heart rate and right atrial and pulmonary wedge pressure were higher; cardiac output, stroke volume and work indexes and ejection fraction were lower; mean arterial and right atrial pressure and systemic resistance were similar. During all phases of exercise in patients with heart failure, pulmonary wedge pressure and systemic vascular resistance were higher and pulmonary vascular resistance remained markedly elevated compared with values in control subjects. Cardiac output was lower in the patients with failure, but appeared to have the same physiologic distribution in both groups during exercise. Although arterial-femoral venous oxygen content difference was higher in patients with heart failure, this increase did not compensate for the reduced blood flow. Even though the maximal oxygen consumption was significantly reduced, femoral venous lactate and pH values were higher than values in control subjects, but femoral venous pH was similar in both groups at their respective levels of maximal exercise. Ejection fraction was lower in those with heart failure at rest and did not increase with exercise. Ventilation in relation to oxygen consumption was higher in patients with failure than in control subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Nursing records prove invaluable.

In the light of a recent murder trial in which two defendants accused of murdering their child, which attracted considerable press coverage, I feel it is necessary to emphasise how important nursing records are.

Different immunological sensitizing regimens and airway responsiveness in vitro to contractile agonists in guinea-pigs.

Groups of guinea-pigs were sensitized to ovalbumin, using different regimens to induce either IgG-like antibodies or IgE-like and IgG-like antibodies and the responsiveness to histamine and carbachol in vitro of tracheal and lung parenchymal strips was determined. EC50 values for histamine and carbachol in both tracheal and lung parenchymal strips were not significantly different for either group of sensitized guinea-pigs or their respective controls. The maximal tension developed in parenchymal strips was not significantly different for either sensitized or control groups. For tracheal strips, maximal tension was not significantly different in each group except in animals with IgG-like antibodies, which developed less maximal tension with histamine than controls. The absence of any increase in maximal tension or any change in EC50 to histamine or to carbachol in tracheal or parenchymal strips from immunized guinea-pigs indicates that immunological sensitization does not increase the responsiveness of smooth muscle to these contractile agonists.

Antitumor agents II: nitrogen analogs of mycophenolic acid.

Mycophenolic acid, a novel antibiotic of low toxicity containing no nitrogen atoms in its structure, induces tumor regression in several murine solid tumor assays. It has been reported in extensive structure-activity studies that chemical modifications on the antibiotic itself reduce or eliminate antitumor activity. With the objective of antitumor activity enhancement, nitrogen-containing analogs of mycophenolic acid were synthesized according to a program directed toward the ultimate synthesis of close bioisosteres of the antibiotic. Intial efforts reported here describe the terpenoid side-chain degradation of N-geranyl-2(1H)-pyridones and N-geranylglutarimides, where the terminal isopropylidene is replaced with a carboxyl group as it occurs in mycophenolic acid. The resulting nitrogen-containing analogs of the antitumor antibiotic were inactive in the l-1210 and Walker 256 tumor systems.