Movement of finger joints induced by synergistic wrist motion

BACKGROUND

An experiment has recently been conducted to evaluate and compare the differences in tendon excursions between the flexor digitorum profundus and superficialis using three mobilization techniques. No previous studies deal with the total joint excursions with constant tendon length. The purpose of this study was to investigate the coordinated motion between the finger and wrist joints resulting from passive tension of the muscles while performing synergistic wrist motion.

METHODS

The relative joint positions of the hand and wrist were measured using a three-dimensional motion analysis system with external retroreflective markers 2 mm in diameter placed on the dorsal surface of the hand. Fifty normal subjects, with a 1:1 gender ration, ranging in age from 20 to 40 years, and with no previous history of upper extremity injury, were recruited for the experiment.

FINDINGS

The relationships of synergistic motion between the wrist and finger joints due to passive tension in the muscles were approximately linear. The ranges of wrist motion averaged 60 degrees extension and 60 degrees flexion. Moving the wrist from flexion into extension induced synergistic finger joint motion as follows: the distal interphalangeal joint angles changed from an average of 12 degrees of flexion to 31 degrees; proximal-interphalangeal joint angles changed from 19 degrees to 70 degrees; and metacarpal phalangeal joints changed from 27 degrees to 63 degrees of flexion.

INTERPRETATION

The relationships of synergistic motion between the wrist and finger joints were systematically documented. Such a relationship could be considered in optimizing the design of dynamic splints used for rehabilitation in post-surgical tendon repair, as well as providing useful information about potential diagnoses of problems with the integrity of the flexor and extensor mechanisms.

Elbow load with various forearm positions during one-handed pushup exercise

This is the first study of the one-handed pushup, and tries to show the effects of forearm rotations. Previous studies of elbow loading have focused on passive loading and small loads, because data from large loads during active exercise is not easy to obtain. In order to investigate the biomechanical impact of hand position on the elbow and the potential trauma mechanisms of outstretched elbow, joint loading across the elbow was analyzed for three forearm rotational positions, neutral, 90 degrees internal rotation and 90 degrees external rotation. Both kinematic and kinetic data were collected from eight volunteers by the Motion Analysis System and a Kistler Force Plate. Statistical analysis of the data delineates the relationship between elbow joint load and hand rotational position during one-handed pushup, and also provides useful biomechanical information for this challenging exercise. The axial and valgus stresses and forces are the major concerns. The peak axial forces exerted on the elbow joint averaged 65 % of the body weight when the hand position was neutral, and was significantly reduced with the hand rotated either internally or externally. The peak valgus shear force with the hand externally rotated was 50 % greater than the other two positions. Thus, outward rotation of the hand is a stressful position that should be avoided during one-handed pushup exercise or forward falls with outstretched hands in order to reduce the risk of elbow injuries.

Effect of elbow flexion on upper extremity impact forces during a fall

OBJECTIVE

The overall objectives are to develop a biomechanical model for a simulated fall with outstretched hand.

DESIGN

Cross-sectional study involving young healthy volunteers in a university research laboratory setting.

BACKGROUND

Little is known about the factors which influence fracture risk during a fall on outstretched hand.

METHODS

A group of 11 male subjects volunteered for this investigation. A set of eight reflective markers was placed bilaterally on selected anatomic landmarks. Subjects were suspended with both elbows extended and wrists dorsiflexed, preparing to impact the ground and force plates from two different fall heights: 3 and 6 cm. Two different postures for the elbows were employed. In the elbow extension experiment, the elbows were extended at all times. In the elbow flexion experiment, the elbows were extended at impact, but then flexed immediately, as though in the initial downward phase of a push-up exercise.

RESULT

Increasing the fall height significantly increased the upper extremity axial forces by 10% and 5%. No significantly different differences were found in the axial forces applied to the wrist, elbow or shoulder between the elbow flexion and elbow extension trials, but the elbow mediolateral shear force was 68% larger (P=0.002) in the extension trials.

CONCLUSIONS

Performing an elbow flexion movement at impact reduces the first peak impact force value and postpones the maximum peak value. Although changing the fall arrest strategy from elbow extension to elbow flexion did not affect the peak impact force on the hand, it did require substantially greater elbow and shoulder muscle strengths.

RELEVANCE

This paper yields insights into how the physical demands of arresting mild falls may relate to upper extremity muscle capacity, joint dislocation and bony fracture.

The effect of changing the foot progression angle on the knee adduction moment in normal teenagers

The effect of changing the foot progression angle on the peak knee adduction moment (KAM) during stance was investigated in 48 teenagers. They underwent gait analysis when walking in three different postures: normal walking, intentional in-toeing, and intentional out-toeing. The peak KAM when in-toeing was the highest and was statistically different from that seen in the normal walking or in the out-toeing posture. These findings may have clinical significance in adult life.

Correlating factors and clinical significance of flexible flatfoot in preschool children

To elucidate the correlating factors and clinical significance of flexible flatfoot (FF) in preschool children of Taiwan, a cross-sectional study was conducted in a research laboratory equipped with a gait analysis facility. Altogether, 377 preschool children (201 boys, 176 girls), ranging in age from 2 to 6 years, were enrolled in this investigation. The results show that age, height, weight, foot progression angle, occurrence of physical knock-knee, and joint laxity score correlate with FF. Children with FF, compared with children without, performed physical tasks poorly and walked slowly, as determined by gait parameters. The FF should not simply be regarded as a problem of static alignment of the ankle and foot complex, but may be the consequence of a dynamic functional change of the lower extremity. Better understanding of the correlating factors and the clinical relevance of FF may prove helpful in deciding on the most appropriate treatment for a particular patient.

Elbow load during pushup at various forearm rotations

OBJECTIVE

Elbow joint loading was evaluated during pushup exercises at various forearm rotations.

DESIGN

Subjects were asked to perform pushup in various forearm rotations: neutral, 90 degrees internal rotation, and 90 degrees external rotation.

BACKGROUND

Training with pushup exercise is good for the muscles and joints of the upper extremities. However, excessive shear forces on the elbow might lead to injuries to either normal trainees or to handicapped people, especially for those who rely on elbow prosthesis.

METHODS

The kinematics and kinetics of the elbow joint were investigated under various forearm rotations.

RESULTS

The loading biomechanics of the elbow joint differed with various forearm rotations. It was noted that greater posterior and varus forces of the elbow are encountered with internal rotation of the hand position and, consequently, full forearm pronation.

CONCLUSIONS

Pushup with hands in internally rotated position should be prevented so as to avoid excessive shear forces or moments.

RELEVANCE

Knowledge of elbow kinematics and kinetics may be helpful in preventing injuries by reducing the elbow shear force with changes of forearm rotation.

Incidence of transitional cell carcinoma and arsenic in drinking water: a follow-up study of 8,102 residents in an arseniasis-endemic area in northeastern Taiwan

A significant association between ingested arsenic and bladder cancer has been reported in an arseniasis-endemic area in southwestern Taiwan, where many households share only a few wells in their villages. In another arseniasis-endemic area in northeastern Taiwan, each household has its own well for obtaining drinking water. In 1991-1994, the authors examined risk of transitional cell carcinoma (TCC) in relation to ingested arsenic in a cohort of 8,102 residents in northeastern Taiwan. Estimation of each study subject's individual exposure to inorganic arsenic was based on the arsenic concentration in his or her own well water, which was determined by hydride generation combined with atomic absorption spectrometry. Information on duration of consumption of the well water was obtained through standardized questionnaire interviews. The occurrence of urinary tract cancers was ascertained by follow-up interview and by data linkage with community hospital records, the national death certification profile, and the cancer registry profile. Cox proportional hazards regression analysis was used to estimate multivariate-adjusted relative risks and 95% confidence intervals. There was a significantly increased incidence of urinary cancers for the study cohort compared with the general population in Taiwan (standardized incidence ratio = 2.05; 95% confidence interval (CI): 1.22, 3.24). A significant dose-response relation between risk of cancers of the urinary organs, especially TCC, and indices of arsenic exposure was observed after adjustment for age, sex, and cigarette smoking. The multivariate-adjusted relative risks of developing TCC were 1.9, 8.2, and 15.3 for arsenic concentrations of 10.1-50.0, 50.1-100, and >100 microg/liter, respectively, compared with the referent level of < or =10.0 microg/liter.

Multiple actinomyces brain abscesses: case report

A case of multiple cerebral abscesses caused by actinomyces is reported in a 37 year old male with mucoepidermoid carcinoma of the right lung. In conjunction with penicillin, sulfonamide and erythromycin, the patient underwent stereotactic surgery for aspiration of the brain abscesses under (CT). The bacteria, considered to originate from the right lung, were identified from the abscess material obtained at surgery. Using proper therapy to control infection and intracranial pressure is important. A lon g term follow up with frequent computerised tomography evaluation has been conducted and the patient outcome has been successful recovery.

The effect of magnitudes and duration of pressure on cerebral cortex in a rat model

The aim of this biomechanical study was to investigate the pressure-time-damage relationship on the cerebral cortex using a rat model. During brain surgery, additional cortical injuries induced by traction have been an important clinical issue. A total of 84 rats underwent a unilateral craniectomy, and conduction by hydrostatic pressure loading through a modified central venous pressure device with various combinations of magnitudes ranging from 0.5 to 10 cm H2O and duration from 0.5 to 20 minutes was then performed. Histopathological examination has exhibited three patterns of clustered, spotted damaged neurons and undamaged neuron. Two best-fitted exponential curves were derived from the data to establish the damaged, critical and tolerable loadings responsible for the neuron viability. This research provides information to enhance understanding of the additional cortex injuries induced by traction. Furthermore, the results may have implications in providing clinical guidance and/or development of alarm systems for minimising cortical damage during surgery.

Sit-to-stand at different periods of pregnancy

OBJECTIVE

This study was performed to determine the biomechanics of chair rising by pregnant women.

DESIGN

Relative body joint position and ground reaction forces were measured by a motion analysis system and one force plate.

BACKGROUND

Physiological and psychological changes during pregnancy impose postural demands and limit the performance of daily living activities such as rising from sitting to standing position.

METHODS

Twenty-four pregnant women, divided into three groups, were studied performing sit-to-stand transition from an armless and adjustable chair. By kinematic and kinetic analysis, the angles and moments of hip, knee and ankle joints were investigated.

RESULTS

The chair height has great influence on knee joint and hip joint moments, but less on ankle joints. In the third trimester for all chair heights, because of a marked increase in abdominal depth, the maximum hip moment is significantly less than that in first trimester, while the maximum knee moment is significantly larger. Pregnant women in third trimester produced larger knee moment during sit-to-stand transition from lower chair height.

CONCLUSIONS

The mechanism of sit-to-stand is affected by the physical changes of pregnant women at different periods of pregnancy, e.g. increased loading of knee joint and decreased hip joint moment, especially in the last trimester period of pregnancy.

Potential of the genetic algorithm neural network in the assessment of gait patterns in ankle arthrodesis

The aim of this study was to develop an empirical model of parameter-based gait data, based on an artificial neural network and a genetic algorithm, for the assessment of patients after ankle arthrodesis. Ground reaction force vectors were measured by force platforms during level walking. Nine force parameters expressed in percentage of body weight and their chronologic incidence of occurrence expressed in percentage of stance phase period were used in modeling. Ten healthy persons and ten patients who had solid arthrodesis of the ankle were recruited in this study for developing the model. By applying the genetic algorithm neural network, the percentage of correct classification was 98.8% and the subset of discriminant parameters was be reduced to 9 out of 18. These key parameters were mainly related to the loading response and propulsive phase. This indicates that there was a reduction in the abilities in cushion impact and push off in the patients after ankle arthrodesis. Finally, the relative distance (Dr) was defined in this study and used in two new patients' examinations to demonstrate its clinical utility.

Gait analysis and energy consumption of below-knee amputees wearing three different prosthetic feet

This study scientifically measures the dynamic gait characteristics and energy consumption of 16 male below-knee amputees, eight vascular and eight traumatic, while wearing solid ankle cushion heel (SACH), single axis and multiple axis prosthetic feet via six-camera motion analysis, metabolic measurement cart and heavy-duty treadmill. Subjective results are additionally determined via questionnaire after testing. Motion analysis showed statistically significant differences at P<0.05 between the SACH, single axis and multiple axis foot in the velocity, cadence, stride length and single limb stance. Significant differences were found in energy consumption between the traumatic and vascular groups, and significant changes in walking under different speeds and different inclines. Results provide quantitative and qualitative information about the dynamic performance of the various feet, which can be helpful in prescribing the optimal prosthetic foot for individual amputees.

Fatal and non-fatal chromobacterial septicemia: report of two cases

Chromobacterium violaceum is frequently found in soil and water in tropical and subtropical regions. The organism rarely causes infection in humans, but is associated with a high mortality rate when it occurs. Septicemia associated with abscess in multiple organs such as the liver, skin, lungs, spleen, lymph nodes, and brain has been reported. We report on 2 patients with systemic infections with Chromobacterium violaceum. One presented with a fulminant course with multiple organ involvement and died 78 days later. The other presented with a milder course and survived after antibiotic therapy. In conclusion, infection with Chromobacterium violaceum is rare but its course is usually fulminant with high mortality especially in patients with sepsis and multiple organ involvement. We hope this report will provide additional information to physicians in the treatment of this disease.

Common abnormal kinetic patterns of the knee in gait in spastic diplegia of cerebral palsy

We studied the kinetic characteristics of the knee in patients with spastic diplegia. Twenty three children with spastic diplegia were recruited and had their 46 limbs categorised into the following four groups: jump (n=7), crouch (n=8), recurvatum (n=14) and mild (n=17). In the crouch pattern, the patients usually had a larger and longer lasting internal knee extensor moments in stance suggesting that rectus femoris had a relatively high activation. In the recurvatum pattern, the internal knee flexor moment was large and long lasting in stance. The biceps femoris showed less activity on EMG although the knee flexor moment was large and we concluded that the soft tissue behind the knee joint provided this flexor moment. In the jump knee pattern there was abnormal power generation at the knee and ankle joints in initial stance, which did not contribute to normal progression but aided upward body motion. In the mild group the kinetic data was similar to that seen in normal children. Knowledge of kinetic patterns in these patients may help in their subsequent management.

Foot progression angle and ankle joint complex in preschool children

OBJECTIVE

The influence of foot progression angle on the ankle joint and the effects on gait patterns and mechanisms in skeletally normal preschool children was investigated.

DESIGN

Kinematics and kinetics of the ankle joint were analyzed for preschool children who were skeletally normal but walked with different foot progression angle.

BACKGROUND

The most frequent reasons for preschool children to be brought to a paediatric orthopaedic clinic are toe-in and toe-out. Without understanding the biological and biomechanical implications, treatment for these problems can be very confusing.

METHODS

Gait analysis was performed in 86 skeletally normal preschool children. Children were grouped according to their foot progression angles. Analysis of the kinematics and kinetics of the ankle joint was intended to elucidate the gait mechanism.

RESULTS

Children with different foot progression angles had distinctive patterns of spatio-temporal parameters, ground reaction force, joint angle, moment, power, and mechanical work of the ankle joints. The differences were organized and explained as different walking patterns and tactics.

CONCLUSIONS

Skeletally normal preschool children with excessive toe-in or toe-out foot progression angles are not necessarily in some diseased status. They were instead related to different walking patterns. Aggressive treatment for these problems is not recommended.RelevanceThese results suggest that toe-in and toe-out are related to walking speed which has distinct influences on the kinematics and kinetics of the ankle joint. Though the observed problems were seemingly only in the transverse plane, they are in fact three-dimensional and have a mutually close relationship. The findings could be linked to the promptness of muscle response and the habits of walking in preschool children. Better understanding of possible mechanisms will help parents and paediatricians decide on the most appropriate treatment for these children.

Comparison of two-dimensional and three-dimensional techniques for determination of facial motion--absolute movement in a local face frame

BACKGROUND AND PURPOSE

Few studies have used motion analysis in the study of facial animation. A facial animation model using an expert vision motion analysis system was developed in this study to quantitatively evaluate absolute movement during five facial animations.

METHODS

Skin markers were adhered to the face of each subject at 16 anatomic landmarks selected to represent the functional movement of the facial muscles. Three of the 16 skin markers were used to establish a local face frame with the origin in the mid-point of the face. All of the coordinates measured in the laboratory frame were rotated and translated to the local face frame for analysis. The trajectory of the facial markers was evaluated from the local face frame when comparing two-dimensional (2-D) displacement of skin markers (frontal plane) with three-dimensional (3-D) values by paired Student's t-test.

RESULTS

Although the correlation of 2-D and 3-D displacements of skin markers was high (r > 0.69), the differences between 2-D and 3-D motion were significant (p < 0.001). The 2-D displacement of skin markers underestimated the 3-D facial animation in each marker and animation. There were no significant differences in the movement of both mouth angles or of the eyes. Thirty repeated measurements of a subject revealed good concentration in 3-D displacement, velocity, and angle of movement in smiling. The measurement error was less than 0.06 mm. The normative displacement of individual anatomic landmarks was evaluated to avoid size differences of individual faces.

CONCLUSIONS

We suggest that the expert vision motion analysis technique is feasible for quantitative evaluation of absolute facial movement and would be useful for further clinical evaluation of patients with facial palsy.

Gait analysis after ankle arthrodesis

The purpose of this study was to employ a computerized motion analysis system to identify the effect of ankle arthrodesis on the three-dimensional kinematic behavior of the rear and fore foot during level walking. A three-segment rigid body model was used to describe the motion of the foot and ankle. The results demonstrated that sagittal plane motion of the hindfoot was significantly decreased in the foot of patients having had ankle arthrodesis compared to normal subjects. The kinematic data indicated a generalized stiffness of the hindfoot on the involved foot in the sagittal plane. Sagittal plane movement in the forefoot and transverse plane movements in the hindfoot and forefoot increased in patients compared to controls.

Physiological knock-knee in preschool children: prevalence, correlating factors, gait analysis, and clinical significance

Physiological knock-knee (PKK) was categorized by measuring intermalleolar distance (IMD), a clinically simple method, to evaluate the prevalence and correlating factors in 305 preschool children. The prevalence in this cross-sectional study was relatively high, and it was age related (p = 0.002; 64, 44, and 34% for ages 3-4, 4-5, and 5-6 years, respectively). The following factors were correlated with PKK: use of walking chair early (p = 0.0001), independently walked late (p = 0.0005), dependently walked longer (p = 0.0001), concurrence with flatfoot (p = 0.001), and angular deformity (toe in/out, p = 0.03). Gait analysis, with spatiotemporal, kinematics, and kinetics parameters, was performed to evaluate the ambulatory significance. Preschool children with PKK have a shorter stride length (p = 0.02) and a slower walking speed (p = 0.004). Dynamic hyperextension of the knee is noted for 8 degrees during the whole gait cycle (p < 0.05). We conclude that PKK is a variable that should be considered in the development of mature gait for preschool children.

Evaluation of enzyme-linked immunosorbent assay for the determination of polycyclic aromatic hydrocarbons in house dust and residential soil

Two commercially available enzyme-linked immunosorbent assays (ELISA) for total polycyclic aromatic hydrocarbon (PAH) and carcinogenic PAH (C-PAH) were evaluated. The testing procedures were refined for application to screening PAH and C-PAH in house dust and soil samples for human exposure studies. The overall method precision expressed as percent relative standard deviation (%RSD) of triplicate real world dust and soil samples was within +/- 29% (12-29%) for PAH ELISA and +/- 21% (5.9-21%) for C-PAH ELISA. Spike recoveries from real world dust/soil samples were 114 +/- 30% for phenanthrene from PAH ELISA and 120 +/- 8.2% for benzo[a]pyrene from C-PAH ELISA. The overall method accuracy for PAH and C-PAH assays cannot be assessed for multiple PAH components in dust/soil samples (which represent real-world samples), because of the assays' cross reactivities with other PAH components. Over 100 dust/soil samples from 13 North Carolina homes and 22 Arizona homes were analyzed by PAH and C-PAH assays, as well as by the conventional gas chromatography/mass spectrometry (GC/MS) method. Statistical analysis showed that dust/soil PAH data from ELISA and GC/MS methods are significantly different. In general PAH ELISA responses were higher than PAH GC/MS responses. The regression analysis showed that the linear relationship between ELISA and GC/MS measurements is not strong in the combined data. The relationship became stronger for the data from the same type of dust/soil samples. The screening performance of ELISA was evaluated based on the frequency distribution of ELISA and GC/MS data. The results indicated that the ELISA PAH and C-PAH assays cannot be used as a quantitative analytical tool for determining PAH in real-world dust/soil samples. However, the ELISA is an effective screening tool for ranking PAH concentrations in similar types of real world dust/soil samples.

[Application and evaluation of multiple exposure photography and motion analysis system in gait measurement]

Accurate techniques to evaluate and quantitate gait patterns have been available in clinical applications for the last 20 years. In this study, by employing multiple exposure photography, the walking velocity, stride length, step cadence and joint angle of the lower limbs were recorded for normal young men during the gait cycle. Data were compared with results from the motion analysis system and related researches. The results showed that multiple exposure photography can also provide quantitative analysis of several important time-distance parameters in the gait cycle.

Strength of the pin-bone interface of external fixation pins in the iliac crest. A biomechanical study

The iliac crest is a frequent insertion site for external fixation pins in treating unstable pelvic or acetabular fractures and in iliofemoral distraction for superiorly dislocated hips. The pin-bone interface is critical for the success of treatment, but studies of the iliac crest are lacking. The purpose of this study was to investigate the strength of the pin-bone interface of different pins and different insertion methods. Four types of commercial pins, Wagner pins, Orthofix cortical and cancellous screws, and AO pins, were driven into sheep iliac crests by 2 methods: the intercortical and the transcortical. Specimens were tested for pullout and bending with an Instron testing machine (Model 1343) at a extension rate of 0.02 mm/sec to failure. The results revealed that the intercortical method had a stronger pullout force than the transcortical in all types of screws (p < 0.05), probably caused by longer insertion in the bone. In the pullout tests, the Wagner pins were the strongest and the Orthofix cancellous screws were the weakest. There were no differences in bending. In the iliac crest, the intercortical method was the better way of driving pins, and the new Orthofix screws were not proven to be stronger than the Wagner pins, nor were the cancellous screws more suitable than the cortical ones.

Study of low-temperature thermoplastic modified custom-molded cervical orthosis for cervical spine fixation

The purpose of this experiment is to use a low-temperature thermoplastic material (Aquaplast) to make a modified custom-molded cervical orthosis. Sixteen normal young subjects who do not have previous cervical problems are tested in this study. This modified orthosis is applied on these volunteers so that external fixation of the cervical spine can be tested. Various roentgenograms for cervical flexion and extension, as well as neutral position and lateral bending, are taken to determine the fixation property of the cervical spine. A study of rotation of the cervical spine is also carried out through goniometer measurements. This clinical study proves that this low-temperature thermoplastic cervical orthosis provides good fixation for the cervical spine, especially in flexion and rotation, but is not suitable for C1- and C2-injured patients.

Measurement of organ volume by single photon emission computed tomography

The aim of this study was to develop a new algorithm for volume determination by single photon emission computed tomography (SPECT). Different algorithms were evaluated through phantom studies. The results show that the algorithm combining moment-preserving bilevel thresholding and best-fit Laplacian second derivative edge detection can provide the most accurate measurement of volume. Besides, this method can be utilized in different SPECT systems with no need for further phantom studies. In patient studies, the results of liver volume calculation have indicated that this is a useful technique in clinical medicine.

Electromyographic analysis of habituation processes of treadmill walking to floor walking

Electromyography (EMG) is an essential tool for assessing muscle performance in human locomotion. The aim of this research is to utilize EMG for assessing the habituation processes of normal adults during treadmill walking compared to floor walking. In this research, EMG activity is presented in linear envelope (LE) form to meet physiological meanings and parameter estimation. The EMG LE is generated from the raw EMG signal through band-pass filtering, rectifying, integration, and normalization procedures. The ensemble averaging of EMG LEs is used to demonstrate the pooled data of six normal subjects. The variance ratio (VR) of the EMG LE is applied to analyze the repeatability of EMG activity and thus to quantify the habituation process of normal adults walking on a treadmill. The habituation results indicated that no pretibial group reached a steady state during 12 minutes of treadmill walking. However the majority of calf groups habituated after 2 minutes of treadmill walking. In addition, changes in EMG phasic activities could be observed for both pretibial and calf groups during treadmill walking.

Significance of acceleration period in a dynamic strength testing study

The acceleration period that occurs during isokinetic tests may provide valuable information regarding neuromuscular readiness to produce maximal contraction. The purpose of this study was to collect the normative data of acceleration time during isokinetic knee testing, to calculate the acceleration work (Wacc), and to determine the errors (ERexp, ERwork, ERpower) due to ignoring Wacc during explosiveness, total work, and average power measurements. Seven male and 13 female subjects attended the test by using the Cybex 325 system and electronic stroboscope machine for 10 testing speeds (30-300 degrees/sec). A three-way ANOVA was used to assess gender, direction, and speed factors on acceleration time, Wacc, and errors. The results indicated that acceleration time was significantly affected by speed and direction; Wacc and ERexp by speed, direction, and gender; and ERwork and ERpower by speed and gender. The errors appeared to increase when testing the female subjects, during the knee flexion test, or when speed increased. To increase validity in clinical testing, it is important to consider the acceleration phase effect, especially in higher velocity isokinetic testing or for weaker muscle groups.

Chemical dissolution of gallstones in Taiwan: an in vitro study

To evaluate the potential for the chemical dissolution of gallstones, 480 stones from 214 patients were studied. The stones were obtained via surgery or endoscopically. They were classified into cholesterol-rich mixed stones, brown pigment stones and black stones. The composition of bilirubin and cholesterol was determined by Fourier transformed infrared spectroscopy. Two per cent tetrasodium ethylenediamine acetate (EDTA), dimethylsulfoxide (DMSO) or methyl-tert-butyl-ethylene (MTBE) were used to dissolve the stones. To enhance solubility, surfactant polysorbate-20 was used to mix two of the individual three solvents. Methyl-tert-butyl-ethylene was found to have the best dissolution ability (by dry weight) 94, 13.4 and 20% for mixed, brown and black stones, respectively. Dimethylsulfoxide resulted in 13, 14 and 25% dissolution and EDTA 9.5, 13 and 16.5%. In contrast, pure water dissolved 4, 6 and 10.4% of the stones, respectively. A combination of the dissolution agents did not enhance the dissolution rate. In fact, the combination of solvents unexpectedly reduced the solubility of the stones: EDTA/MTBE was 17.5, 6.7 and 16.0%; DMSO/MTBE 43.2, 21.9 and 18.0%; DMSO/EDTA 9.1, 7.0 and 9.6%. In conclusion, cholesterol-rich mixed stones were able to be dissolved using MTBE but results of contact dissolution for gallstones are still far from satisfactory.

(Imidazolylphenyl)pyrrol-2-one inhibitors of cardiac cAMP phosphodiesterase

Seven 3-alkyl-4-aryl-1,5-dihydro-2H-pyrrol-2-ones were prepared as potential inhibitors of cardiac cAMP phosphodiesterase (PDE). The design of these compounds made use of rolipram, a known inhibitor of the brain cAMP PDE isozyme, as a lead structure and was guided by a model which describes the features required for potent inhibition of the cardiac isozyme. Syntheses for the new compounds are described, together with the results of theoretical and crystallographic studies aimed toward ascertaining their three-dimensional structures. The activities of these compounds as inhibitors of the cardiac and brain cAMP PDE isozymes and their positive inotropic activity in ferret papillary muscle are also reported. Selected compounds were further examined in an in vivo hemodynamic model. One compound 1,5-dihydro-4-[4-(1H-imidazol-1- yl)phenyl]-3-methyl-2H-pyrrol-2-one, was identified as a potent and selective positive inotropic agent and inhibitor of cardiac cAMP PDE.

[Evaluation of the effects of pulling angle and force on intermittent cervical traction with the Saunder's Halter]

Intermittent cervical traction with proper angle and force is an effective treatment for cervical syndrome. The goals of therapy are effective traction for the affected segments without further damage to the soft tissue. The purposes of this study were to find the traction angle and force which results in the best therapeutic effect. The effect of cervical traction was evaluated by cervical roentgenography, by examining the distance of the posterior margin of the intervertebral space. For a study of the proper angle of traction, intermittent cervical traction was applied to 20 healthy normal volunteers in a supine position with a constant traction force of 15 kgf. The traction lasted for 8 seconds followed by unloading for 4 seconds and the application was alternated after 10 minutes. The elongated gaps of the posterior vertebral margins obtained from the different neck flexion angles of 35, 30, 25, 20 and 15 degrees were compared. Traction of under 30 degrees was longest for the levels of C4- 5 and C5-6. For the C6-7 and C7-T1 levels, traction was longest under 35 degrees. For study of the minimal effective traction force, the same procedures of intermittent cervical traction were applied to another 15 healthy normal volunteers, except the neck was fixed in a flexion of 35 degrees, and the traction force was 9, 12, 15 and 18 kgf. The best results were noted with a traction force of 15 or 18 kgf. However, there were more complaints of neck discomfort after traction with a force of 18 kgf.

Synthesis and biological activity of angiotensin II analogues containing a Val-His replacement, Val psi[CH(CONH2)NH]His

The dipeptide mimic Val psi[CH(CONH2)NH]His (4) was incorporated into angiotensin II (AII) analogues to provide an octapeptide saralasin derivative (29) as well as tetrapeptide analogue 19. Three C-terminal tetrapeptides (21, 25, and 28) were also prepared. All compounds were tested for their ability to displace 3H-AII from rabbit adrenal gland homogenate and as antagonists of AII and AI on guinea pig ileum. The octapeptide analogue 29 was 700 times less active than the parent peptide 30. All the C-terminal fragments 19, 21, 25, and 28 have no measurable AII antagonist activity. Of the four tetrapeptide fragments, only 21 showed any appreciable binding activity.

[Quantification of acetabular coverage in normal adult]

Quantification of acetabular coverage is important and can be expressed by superimposition of cartilage tracings on the maximum cross-sectional area of the femoral head. A practical Autolisp program on PC AutoCAD has been developed by us to quantify the acetabular coverage through numerical expression of the images of computed tomography. Thirty adults (60 hips) with normal center-edge angle and acetabular index in plain X ray were randomly selected for serial drops. These slices were prepared with a fixed coordination and in continuous sections of 5 mm in thickness. The contours of the cartilage of each section were digitized into a PC computer and processed by AutoCAD programs to quantify and characterize the acetabular coverage of normal and dysplastic adult hips. We found that a total coverage ratio of greater than 80%, an anterior coverage ratio of greater than 75% and a posterior coverage ratio of greater than 80% can be categorized in a normal group. Polar edge distance is a good indicator for the evaluation of preoperative and postoperative coverage conditions. For standardization and evaluation of acetabular coverage, the most suitable parameters are the total coverage ratio, anterior coverage ratio, posterior coverage ratio and polar edge distance. However, medial coverage and lateral coverage ratios are indispensable in cases of dysplastic hip because variations between them are so great that acetabuloplasty may be impossible. This program can also be used to classify precisely the type of dysplastic hip.

A topographical model for the c-AMP phosphodiesterase III active site

With this minireview, concepts about how c-AMP and various inhibitor molecules interact with the phosphodiesterases seem to have come full-circle. It will be proposed and elaborated herein that an understanding of SAR for the newest, "second generation" PDE inhibitors is best accomplished by adopting a model that supposes that these compounds are transition state inhibitors. The analysis finds an interesting parallel with early studies where it was recognized that c-AMP adopts a trigonal bipyramid transition state during hydrolysis. The dynamic interaction of ligands with the phosphodiesterase enzymes will also be made evident when simple algebraic expressions are shown to be inadequate for predicting inhibitor potencies. The latter are apparently complicated by cooperative or synergistic relationships that occur among the various binding sites within the receptor. Finally, implications that can be derived from certain topographical features of the model are discussed relative to a range of potential therapeutic indications.

Cardiotonic agents. 6. Histamine analogues as potential cardiovascular selective H2 agonists

Twenty-six alkyl and aralkyl histamine analogues were prepared as potential cardiotonic agents. Compounds were designed to allow interaction with a putative secondary aryl binding site at the H2 receptor, the presence of which was inferred from the structure of cyprohepatadine, which is known to have H2-antagonist properties. The compounds were examined for inotropic activity in ferret papillary muscle. Potent inotropic activity was generally found in N-alkyl- and N,N-dialkylimidazole-4-ethanamines, whereas N-(amidoalkyl)imidazole-4-ethanamines and N-alkylimidazole-4-propanamines were at best weakly active. Five compounds were examined in screens designed to assess hemodynamic effects and gastric acid secretion in vivo. Two of these compounds, alpha-(3-phenyl-2-transpropenyl)-1H-imidazole-4-ethanamine and N-heptyl-1H-imidazole-4-ethanamine, showed positive inotropic activity with minimal effects on heart rate and mean arterial pressure in vivo; however, both compounds were found to stimulate gastric acid secretion. These results demonstrate that selectivity between various H2-receptor-mediated activities can be obtained with substituted histamine analogues.

[Application and evaluation of the VICON system in gait analysis]

By employing the VICON system, segment angular displacement, velocity and acceleration of the lower limbs were achieved from an Above-Knee (A/K) Amputee using a constant friction prosthesis during the swing phase of the gait cycle. By applying computer for data analysis and inputing anthropometric data of the (A/K) Amputee, kinematic trajectory and a stick diagram of lower limbs were obtained. The data were then compared with those obtained from normal subjects. The results showed that the VICON system can provide quantitative analysis of several important parameters in the gait cycle and that it is very helpful in the evaluation and rehabilitation training of abnormal gait.

[A case report and metallurgical analysis of broken Luque rod]

Wire breakage is frequently mentioned in Luque rod instrumentation with segmental sublaminar wiring, but breakage of the Luque rod is rare. A case report of a broken Luque rod in a patient following a scoliosis post-corrective operation is presented and a metallurgical analysis is provided to evaluate the mechanism of breakage. In the metallurgical analysis, we find many slots and dimples on the rod surface which were induced by an inappropriate bending apparatus and bending manipulation. These defects resulted in a stress concentration effect and initiated fatigue. As for the stress on the rod, this resulted from the force correcting the scoliotic deformity plus the load resulting from patient's daily activity, which increased the progression of fatigue and then induced the final breakage. So, to avoid Luque rod breakage we suggest that the bending manipulation be done appropriately, with external orthosis given to those patients with severe deformity or who are daily very active.

Cardiotonic agents. 2. (Imidazolyl)aroylimidazolones, highly potent and selective positive inotropic agents

A series of 4-alkyl-1,3-dihydro-5-[(1H-imidazolyl)benzoyl]-2H-imidazol-2-ones 9 was synthesized and evaluated in vitro for positive inotropic and cyclic AMP phosphodiesterase inhibitory activity. A wide range of inotropic and enzyme-inhibitory potencies was observed, substitution on the imidazolyl moiety being the major determinant of activity. The 4-ethyl-5-[4-(1H-imidazol-1-yl)benzoyl] congener 9g exhibited the highest potency in vitro. Incorporation of a methyl group at the imidazolyl 2-position gave 9h, which was less potent but remarkably selective in vivo for positive inotropic effects over heart rate and hypotensive effects.

Regeneration of plants from tobacco protoplasts and some factors affecting the plant differentiation

Protoplasts were isolated from the cell suspension culture derived from leaf and stem calli of tobacco (Nicotiana tabacum cv. Ko Hsin No. 1) haploid pollen-plants. After 12 hr in the liquid culture medium, the protoplasts became oval-shaped, and produced a new cell wall. The first division of the newly formed cells was completed after 24 hr in culture. After 4 weeks in culture, the yellowish calli reached 1 mm in size were then transferred to an auxophyton. 18 days later, the calli became 3-4 mm in size. After the calli were transferred to a differentiation culture medium, shoots and roots soon turned up. Regeneration of whole plants was obtained thereafter. The division and differentiation of regenerated cells were affected not only by the calli originated from different organs and their, age, but also by the basic components of the differentiation culture medium and the type of cytokinin used.