COMBINED EFFECT OF THERMAL LOAD AND MECHANICAL LOAD IN TRANSTIBIAL PROSTHESIS. AN EMPIRICAL STUDY.

UNLABELLED: Probably the most important factor in evaluating a patient's prosthesis is quality of life. Transtibial amputations, are among the most frequently performed major limb amputations. Many individuals with transtibial amputations successfully achieve rehabilitation at or near their preamputation levels. Discomfort in prosthetic sockets continues to be a critical challenge faced by both prosthetists and amputees. MATERIAL AND METHODS: This paper proposes a fusion Graphic User Interface that combines two types of information (pressure and temperature). Data from pressure sensors and thermistors (an electrical resistor whose resistance is greatly reduced by heating, used for measurement and control) placed on the stump in transtibial prosthetics are collected in real time using a National Instruments Data Acquisition device. RESULTS: All the data stored in files are available for offline processing. The user has the possibility to analyse the signal by zooming or positioning the marker and window on different parts of signal. A complex analysis that involves the pressure and temperature for a location (where both sensors are placed) is available in time domain. CONCLUSIONS: Blunt-prosthesis interface is characterized by few parameters among the most important are pressure and friction. The action of these parameters during static and dynamic stage is very important because their actions can produce lesions of skin at the level of interface. Despite the advancements in surgical techniques and prostheses, much still needs to be done. We made certain that the sensors were in the same location by pressing on specific cells on the residual limb during various stages of the experimentation. The highest pressures recorded were during the stance phase of walking. The curve that shows the temperature evolution or pressure in one point could differ in different points from patient to patient.

Analyse of socket-prosthesis-blunt complex for lower limb amputee using objective measure of patient's gait cycle.

UNLABELLED: The prosthetic application is a highly complex process. Modeling and simulation of biomechanics processes in orthopedics is a certainly field of interest in current medical research. Optimization of socket in order to improve the quality of patient's life is a major objective in prosthetic rehabilitation. A variety of numerical methods for prosthetic application have been developed and studied. MATERIAL AND METHODS: An objective method is proposed to evaluate the performance of a prosthetic patient according to surface pressure map over the residual limb. The friction coefficient due to various liners used in transtibial and transfemoral prosthesis is taken into account also. RESULTS: Creation of a bio-based modeling and mathematical simulation allows the design, construction and optimization of contact between the prosthesis cup and lack of functionality of the patient amputated considering the data collected and processed in real time and non-invasively. The von Mises stress distribution in muscle flap tissue at the bone ends shows a larger region subjected to elevated von Mises stresses in the muscle tissue underlying longer truncated bones. CONCLUSIONS: Finite element method was used to conduct a stress analysis and show the force distribution along the device. The results contribute to a better understanding the design of an optimized prosthesis that increase the patient's performance along with a god choice of liner, made by an appropriate material that fit better to a particular blunt. The study of prosthetic application is an exciting and important topic in research and will profit considerably from theoretical input. Interpret these results to be a permanent collaboration between math's and medical orthopedics.

Casein secretion and cytological differentiation in mammary tissue from bulls of high or low genetic merit.

We evaluated tissue content and secretion of milk proteins by mammary parenchymal explants prepared from tissue of mature Holstein bulls as a possible index for genetic merit. Explants from eight selection-line and eight control-line bulls were cultured for 48 or 96 h in medium with 5% fetal bovine serum with or without the addition of lactogenic hormones. Four selection-line and four control-line bulls were also treated for 7 d with estrogen and progesterone or placebo before tissue was removed on d 15 of the experiment. Overall, tissue content and secretion of casein were increased approximately twofold in selection-line bulls. Differences between genetic lines were evident only with the addition of lactogenic hormones. However, treatment of bulls with steroids was not necessary for casein secretion or detection of differences between genetic lines. Averaged for both lines, 96-h media concentrations of casein were 89-fold greater for explants cultured with added lactogenic hormones. Epithelial cells were classified as nonsecretory, droplet-containing, or degenerated. The appearance of droplet-containing cells was markedly increased in cultures supplemented with lactogenic hormones, and the cells were most often located within epithelial folds or pockets. Only occasionally did we observe areas of alveolar-like tissue. The data demonstrate that it is possible to induce the secretion of casein in mammary explants prepared from sexually mature bulls, that lactogenic hormones markedly stimulate secretion, and that differences in genetic merit may be expressed.

Florfenicol pharmacokinetics in lactating cows after intravenous, intramuscular and intramammary administration.

Pharmacokinetics of florfenicol 30% injectable solution was determined in lactating cows after intravenous, intramammary and intramuscular administration. Serum concentration-time data generated in the present study were analysed by non-compartmental methods based on statistical moment theory. Florfenicol half-life was 176 min, mean residence time 129 min, volume of distribution at steady-state 0.35 L/kg, and total body clearance 2.7 mL/min.kg after intravenous administration at 20 mg/kg. The absorption after intramuscular administration appeared slow and the kinetic parameters and the serum concentration vs. time curve were characteristic of absorption rate-dependent elimination. The absorption after intramammary administration of florfenicol at 20 mg/kg was good (53.9%) and resulted in serum concentrations with apparent clinical significance. The intramammary administration resulted in serum florfenicol concentrations that were significantly higher than the respective serum concentrations following intravenous administration 4 h after administration and thereafter. Florfenicol absorption was faster from the mammary gland than from the muscle. The maximum serum concentrations (Cmax) were 6.9 micrograms/mL at 360 min after intramammary administration and 2.3 micrograms/mL at 180 min after intramuscular administration. The bioavailability of florfenicol was 54% and 38% after intramammary and intramuscular administration, respectively. The Cmax in milk was 5.4 micrograms/mL at 180 min after intravenous and 1.6 micrograms/mL at 600 min after intramuscular administration.

Effect of in vitro and in vivo migration of bovine neutrophils on binding and expression of Fc receptors for IgG2 and IgM.

Binding of endogenous and exogenous homologous IgG2 and IgM to bovine neutrophils before and after in vitro migration through micropore filters, and in vivo migration through mammary tissues after intramammary injection of endotoxin was evaluated by use of flow cytometry. Immunoglobulin binding to neutrophils at 4 and 37 C was also evaluated. Before and after in vitro migration, neutrophils with endogenously bound IgG2 and IgM averaged 1 and 2% and 23 and 7%, respectively. Before and after in vivo migration, IgG2 and IgM binding averaged 1 and 7% and 26 and 15%, respectively. Before and after in vitro migration, binding of purified IgG2 and IgM averaged 75 and 67% and 8 and 24%, respectively. Before and after in vivo migration, percentage of neutrophils binding purified IgG2 and IgM averaged 92 and 98% and 54 and 70%, respectively. When serum was used as a source of exogenous immunoglobulins, binding of total IgG after in vitro migration increased from 5% to 28% and of IgM from 4% to 20%. After in vivo migration, binding increased from 21% to 47% and from 24% to 56%, respectively. Exogenous binding of IgG2 at 4 and 37 C averaged 75 and 84%, and binding of IgM averaged 8% at either temperature. Endogenous IgG2 was unaffected by temperature, however, binding of IgM decreased from 23% at 4 C to 2% at 37 C. These data indicate that endogenous binding was higher for IgM before migration than after migration, in vitro and in vivo. Furthermore, migration in vivo through cellular matrices induced receptor upregulation for IgG and IgM.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow cytometric analysis of neutrophils in cows' milk.

Procedures were developed to count neutrophils in milk, using a flow cytometer. Milk samples from 2 experiments were counted: 1 with 4 noninfected cows and a second with 5 noninfected cows that were injected with endotoxin in 2 mammary quarters. Thus, the procedures were evaluated on normal milk and on that with high somatic cell count. Flow cytometric procedures involved fluorescence detection (from the dye carboxydimethylfluorescein diacetate) to distinguish intact and viable from fragmented cells, forward light scatter to detect cell size differences, and right-angle side scatter to detect cellular granularity. High fluorescence, large size, and high degree of granularity identified viable neutrophils. For all samples, neutrophils were also counted manually, using the cytologic centrifugation approach to create the slides; manual counts were used as the standard for comparison. In experiment 1 (normal milk), mean values for percentage of viable neutrophils estimated by manual and flow cytometry procedures agreed closely (26% vs 25.8% for foremilk and 28.8% vs 26.6% for bucket milk). Sources of variation in manual and flow cytometric estimates of percentage of neutrophils were examined. Cow variation was significant (P < 0.01) for manual and flow cytometric counts, but was larger for flow cytometric counts. Day-to-day variation in counts on milk from the same cow was negligible for manual counts, but was significant (P < 0.01) for flow cytometric counts.(ABSTRACT TRUNCATED AT 250 WORDS)