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Biomedical subjects

R A Mostardi

Publications and source records attributed to R A Mostardi.

At least 19 recordsLinked to original sources
PubMed1999

In vitro response of human fibroblasts to commercially pure titanium.

The generation of metal particles through surface wear of prosthetic joints has been associated with biological reactions that may lead to prosthetic component loosening. The role of the macrophage in these reactions has been studied extensively, but that of the fibroblast has not. The few fibroblast studies that there have been have shown that particles of several metals, with sizes over a wide range, can promote cytokine release and may cause cell necrosis. The intent of this study was to determine if there are metal particle exposure threshold levels that result in morphological changes and cell necrosis of fibroblasts in peri-articular tissues. Retrieved human fibroblasts (superior medial plica) were cultured in standard fashion and then were exposed to various particle dosages of commercially pure Titanium (cpTi). Cell morphological changes and necrosis were observed to occur when the total mass of the particle dosage exceeded a threshold level. These data imply that these cell responses occur at threshold levels of wear particle exposure.

Biocompatible Materials↗
PubMed1997

Response of human fibroblasts to tantalum and titanium in cell culture.

The loosening of total joint arthroplasties (TKA) with associated osteolysis has been a persistent problem in orthopaedics. Wear debris from prosthetic devices including Titanium (Ti) is involved in this process. Mechanisms for this osteolytic process are unclear. The purpose of this study was to compare the biological response of Ti and Tantalum (Ta) on retrieved human fibroblasts. Fibroblasts were retrieved from human volunteers and cultured using standard techniques. Twenty-five (25) ml culture flasks were seeded with cells and when reaching confluency four concentrations of Ti and Ta were added. Their mean size was less than 3 microns for both metals and gram weights were 0.0048. 0.0096, 0.048, and 0.096 gms. After ten (10) days the cells were fixed, stained and photographed. For both Ti and Ta, the lowest concentration had little effect on the cells, while at the two higher concentrations, nearly all of the cell were killed. Since both of the metals tested are considered to be inert with respect to toxicity, these results would suggest that the observed cell death, seen equally for both metals, was due to the size and concentration of the particles and not to the metals tested. Mechanisms are currently being investigated which include mechanical as well as chemical factors.

Cell Survival↗
PubMed1992

Isokinetic lifting strength and occupational injury. A prospective study.

One hundred seventy-one nurses had their back strength evaluated on an isokinetic lifting device and filled out an epidemiologic questionnaire. They were then followed prospectively for 2 years to determine the incidence of job-related low-back injuries. The data were analyzed to determine if the injury incidence correlated with any of the strength or epidemiologic variables collected during the original evaluation. Average peak force measured during the isokinetic lift was 63.8 kg + 13.6 kg at a lift speed of 30.5 cm/sec and 59.1 kg + 14.9 kg at a lift speed of 45.7 cm/sec. Sixteen nurses reported an occurrence of job-related low-back pain or injury during the 2-year prospective period. Discriminate statistical techniques showed that none of the strength or epidemiologic variables correlated with the incidence of pain or injury or explained significant amounts of variance when the variables were regressed on strength or work calculated from the lift force/lift height data. It was concluded that in this high risk population, in which loads are heavy and lifting postures are variable, the use of low-back strength or prior history of pain or injury are poor predictors as to subsequent low-back pain or injury.

Adult↗
PubMed1992

Myoelectric activity and sequencing of selected trunk muscles during isokinetic lifting.

Trained weight lifters lift heavy loads without a concomitant degree of acute low-back injuries. To study the process by which large loads are lifted with minimal injury, integrated electromyographic signals were recorded from four large muscle groups: gluteus maximus, quadriceps, latissimus dorsi, and erector spinae in 4 weight lifters and 11 asymptomatic control subjects. These signals were recorded during a floor-to-knuckle-height isokinetic lift (dead lift) at 30.5 and 45.7 cm/sec. The signals were normalized for the height of the lift and the maximal isokinetic integrated electromyographic activity. The weight lifters achieved maximal force at 50% of maximal lift height, whereas the control subjects achieved it at 67%. Although not statistically significant, the weight lifters used the gluteus maximus more during the early stages of the lift, perhaps contributing to earlier development of force. This process would stabilize the pelvis and permit the erector spinae to extend the trunk more efficiently. The weight lifter then completed the lift with prolonged and increasing activity in the quadriceps. This technique may minimize the required force in the erector spinae and the forces on the low-back structures. Clinical implications include more effective strength training of lifting muscle groups other than spinal extensors and the teaching of lifting strategies employed by weight lifters in low-back rehabilitation and work-hardening programs.

Back↗
PubMed1988

Comparison of functional outcome of total hip arthroplasties involving four surgical approaches.

One hundred thirty-seven total hip arthroplasty patients had a follow-up evaluation consisting of an orthopaedic physical evaluation, isokinetic strength testing, and collection of demographic and surgical information from medical records. The intraoperative variables of surgical time and blood loss and the functional outcome status of the subjects, as demonstrated by D'Aubigne--Postel ratings and isokinetic strength tests, were compared for various trochanteric management techniques: no osteotomy; complete Charnley-type osteotomy; sharp abductor release; and a wafer technique, in which a wafer of bone was osteotomized from the trochanter to release the abductors. A comparison of the mean values for the variables indicated that the wafer and sharp techniques were superior to the complete and no osteotomy techniques. The wafer technique resulted in statistically significant superior isokinetic strength measured in adduction, flexion, and extension. Surgical time was significantly greater in the complete osteotomy cases and blood loss was least in the wafer cases, although these differences were not significant.

Femur↗
PubMed1987

Simulated lift testing using computerized isokinetics.

Eighty-four volunteer asymptomatic men between 18 and 40 years of age were evaluated as to their ability to lift. An innovative isokinetic device was used to measure lifting force. This device does not isolate any specific body part, yet it measures the muscular force of lifting an object whose speed of ascent is controlled. Two lifting methods (bent knee, straight leg) and two foot positions were used. The results indicate the bent-knee lift method and forward-foot position was the position of optimal force production. Force production increase was inversely proportional to age. The authors concluded that the isokinetic lift device has promising capabilities to produce repeatable data and may be advantageous in generating standards for rehabilitation and specific job criteria.

Adolescent↗
PubMed1986

The effect of recent life events stress, life assets, and temperament pattern on cardiovascular risk factors for Akron City police officers.

Police officers, as a group, experience many occupational demands with physiological and psychological effects that could be harmful to their health. A primary objective of this study was to analyze specific behavioral and physiological risk factors that could lead to hypertension and accelerated coronary artery disease. Three hundred thirty-one male Akron City police officers participated in the study. A group of volunteer males (n = 48) who worked in city clerical jobs were used as controls. Questionnaires were administered in order to measure such behavioral variables as recent life change, life assets, and temperament pattern. Blood chemistry and physiological variables were also measured. The police officers had higher diastolic blood pressure (DBP), norepinephrine (NE) levels, and recent life change unit (LCU) scores than the control group. Increased hostility and depression scores were associated with higher DBP and recent LCU scores and lower life asset unit (LAU) scores. Individuals with higher "dominant" scores and moderate to high recent LCU scores had higher cardiovascular risk factors than those with moderate to high recent LCU scores who were ranked as "subordinate." Rotating shift workers had abnormally elevated NE levels, which, if not controlled, may lead to higher cardiovascular risk. Behavioral intervention programs have been introduced with the goals of reducing stress, increasing life assets, and teaching relaxation techniques.

Adult↗
PubMed1981

Inducibility of aryl hydrocarbon hydroxylase in BALB/c/ki mice exposed to urban air pollution.

In two separate experiments BALB/c/ki mice were exposed to urban air pollution. Mice exposed to clean air served as controls. In both experiments there were no obvious quantitative or qualitative differences in lung or liver tissue examined by light microscopy. In both experiments higher aryl hydrocarbon hydroxylase activities and higher trace metal concentrations were observed in the mice exposed to polluted urban air. These data are interpreted in terms of health hazards of urban air pollutants.

Air Pollutants↗
PubMed1981

Exercise training using arms and legs versus legs along.

This study was undertaken to determine whether levels of conditioning associated with conventional leg work are comparable to those associated with both arm and leg work. Six healthy men conditioned for 6 weeks using both arms and legs while a similar group of 5 men conditioned using legs alone. The subjects trained 3 times per week on a bicycle ergometer, and covered a distance of 3 miles (4.83 km) per session using interval training techniques. Oxygen consumption (VO2) and heart rate (HR) were the primary comparative measures. There were no differences in improvement of maximal aerobic power between the 2 groups. However, the arm and leg subjects were able to do more work at a lower HR during the conditioning program. This implies considerably less physical stress on the heart and skeletal muscle, and indicates that the feeling of stress is related to metabolic rate per square area of working muscle rather than to total metabolism. Since this type of conditioning provides high levels of improvement in aerobic power wit less demands on the myocardium, it is suggested that arm and leg exercise be incorporated in the rehabilitation of cardiac patients.

Adult↗
PubMed1975

Chronic cannulation for intermittent intravenous fluid administration.

A system is described for rapid and effective venous cannulation for long-term administration of fluids in rabbits. This method is completely free of any harness or sling-type apparatus and in no way interferes with the normal mobility of the animal. The animals maintained in this way have participated in programs of tri-weekly administration (2-3 ml/dose) of fluid for as long as 5 mo.

Animals↗