Biomedical subjects
Publications and source records attributed to J Hamill.
Familial hyperparathyroidism and parathyroid carcinoma are rare diseases. A case of parathyroid carcinoma in an 8-year-old girl whose mother had previously undergone parathyroidectomy for primary hyperparathyroidism is reported. Parathyroid carcinoma in a preadolescent child has not been described previously, and may have a familial basis.
The purpose of this study was to investigate the influence of midsole durometer on mechanical and hematological responses during a prolonged downhill run. Twenty-four men completed a 30-min downhill run (-12% grade) wearing either soft, medium, or hard midsole shoes. Data describing mean peak tibial acceleration (PTA), stride frequency, plasma free hemoglobin, hemoglobin concentration, hematocrit, and creatine kinase (CK) were collected. While there were no significant differences in PTA among midsole durometer shoes, PTA increased by 20% after the first 5 min of the run over all other time intervals during the run (p < .05). Hemolysis showed a 50.2% increase from prerun to postrun values (p <.05). CK increased from the prerun state to 24 hr after the run (p <. 05). Downhill running, irrespective of midsole durometer, showed increased levels of legshock, hemolysis, and muscle damage over values that are present in the literature for a level running protocol.
Over 1500 population database samples comprising African Americans, Caucasians, Hispanics, Native Americans, Chamorros and Filipinos were typed using the PowerPlex 16 and the Profiler Plus/COfiler kits. Except for the D8S1179 locus in Chamorros and Filipinos from Guam, there were eight examples in which a typing difference due to allele dropout was observed. At the D8S1179 locus in the population samples from Guam, there were 13 examples of allele dropout observed when using the Profiler Plus kit. The data support that the primers used in the PowerPlex 16, Profiler Plus, and COfiler kits are reliable for typing reference samples that are for use in CODIS. In addition, allele frequency databases have been established for the STR loci Penta D and Penta E. Both loci are highly polymorphic.
OBJECTIVE: The purpose of this study was to determine if high-arched and low-arched runners exhibit different injury patterns. DESIGN: Non-randomized, two-group injury survey. BACKGROUND: Running-related injuries are thought to be related, in part, to lower extremity structure. High-arched and low-arched runners with their different bony architecture may exhibit very different lower extremity mechanics and, consequently, different injury patterns. It was hypothesized that high-arched runners will exhibit a greater incidence of lateral injuries, skeletal injuries and knee injuries while low-arched runners will show a greater incidence of medial injuries, soft tissue injuries and foot injuries. METHODS: Twenty high-arched and 20 low-arched runners were included in this study. Running-related injuries were recorded and divided into injury patterns of medial/lateral, bony/soft tissue and knee/foot and ankle for both high-arched and low-arched runners. A chi(2) analysis was then employed in an attempt to associate injury patterns with arch structure. RESULTS: High-arched runners reported a greater incidence of ankle injuries, bony injuries and lateral injuries. Low-arched runners exhibited more knee injuries, soft tissue injuries and medial injuries. CONCLUSIONS: Based on these results, high and low arch structure is associated with different injury patterns in runners. Relevance. Different injury patterns are present in individuals with extreme high arches when compared to those with extremely low arches. These relationships may lead to improved treatment and intervention strategies for runners based on their predisposing foot structure.
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AIMS: To examine the impact of a standardised trauma form for documentation in cases of major trauma, a prospective study was undertaken. METHODS: Records written by medical staff pertaining to the assessment and treatment of major trauma patients in the resuscitation room were scored against a panel of parameters derived from advanced trauma life support guidelines. Demographics, aetiology, trauma scores and outcome data were obtained from a trauma registry. Attitudes of medical staff involved in major trauma to the trauma form were assessed using a questionnaire. RESULTS: The trauma form was used in 53 of 69 (76.8%) consecutive cases of major trauma seen over a three month period. No significant differences existed in demographics, aetiology, trauma scores or outcome between form and formless groups. In the form group, a median of 44 of 51 (86.3%) relevant information parameters were documented versus 32 of 51 (62.7%) in the formless group, p < 0.0001. A positive approach to the trauma form was indicated by the questionnaire results. CONCLUSION: The use of a standardised form improves documentation in major trauma.
BACKGROUND: The association between pelvic fracture pattern and the need for pelvic arterial embolization remains controversial. To address this issue, a study of the experience at Auckland Hospital was undertaken. METHODS: Review was undertaken of a trauma database, blood bank database, patient records and pelvic radiographs. Of the 364 pelvic fracture patients admitted over a 4-year period, 76 were transfused with 6 or more units of blood in the first 24 h and these constitute the study population. RESULTS: Embolized patients were older (median age 42 vs 29.5 years; P < 0.05) and had a higher abbreviated injury score for the pelvic girdle (median 3 vs 2; P < 0.05) compared to non-embolized patients. Revised trauma score (median 7.69 vs 7.55), injury severity score (median 29 vs 30.5), morbidity (55 vs 39%) and mortality (45 vs 32.1%) rates did not differ significantly between embolized and non-embolized groups, respectively. The median blood transfusion requirement in the first 6 h from injury was 14 units in embolized and 8 units in non-embolized patients (P = 0.005). Embolization was required in 12 of 27 (44.4%) patients with fracture patterns indicative of major pelvic ligament disruption, whereas seven of 38 (18.4%) patients without these fracture patterns required embolization (P < 0.05). CONCLUSIONS: The need for pelvic embolization correlated with fracture patterns that indicated major ligament disruption, although the relationship was not sufficiently strong to warrant change to current indications for pelvic angiography.
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BACKGROUND: In order to identify differences between children and adults with small bowel rupture (SBR) and to determine if a single diagnostic approach could be taught to paediatric and adult surgeons, a review of the experience at a children's and an adults' hospital was performed. METHODS: Using the hospital patient database 17 children were identified with SBR over a 13.6-year period, and clinical records were available for review for 14. Using a trauma registry 16 adults were identified with SBR over a 4.7-year period and clinical records were reviewed in all 16. RESULTS: The population incidence was 0.48/100000 per annum in children and 0.58/100000 per annum in adults. Motor vehicle crash was a less common mechanism of injury in children (35.7%) than in adults (75%). The time from injury to presentation (presentation interval) was significantly longer in children than in adults, even after excluding child abuse cases (median 2.9 h vs 65 min, respectively). The injury severity score was lower in children (median: 10) than in adults (median: 16.5). Peritoneal signs on follow-up examination were documented in 54.6% of children and in 90.9% of adults in whom follow-up examination was performed. Clinical findings on admission, findings on computed tomography, indications for operation and outcome were similar in children and adults. CONCLUSION: Children differed from adults in aetiology, longer presentation interval and fewer associated injuries. Similarities in diagnostic parameters suggest that a single diagnostic approach could be taught for children and adults provided that the limitations of physical examination in small children are recognized.
UNLABELLED: Comparisons of ground reaction forces (GRF) during gait are not typically conducted with blinding of the varied shoe characteristic, raising concerns related to the existence of a placebo effect, or a subject response based on a perceived expectation of change. PURPOSE: To determine whether investigator comments on shoe construction influenced GRF measures and ratings of shoe cushioning during walking. METHODS: 19 female college students volunteered for a study presented as a test of a new shoe material. The study involved walking (2.5 m x s(-1)) under three shoe conditions (SC). Shoes in SC2 and SC3 were harder than those in SC1, but shoes in SC1 and SC3 looked similar. Subjects in a mislead group (N = 9) were told SC1 and SC3 were baseline measures in a standard shoe, with SC2 misleadingly described as a shoe constructed of unique new material. A control group performed the same three conditions without investigator description. GRF data were collected for 10 trials for each subject in each condition, and subjects rated the perceived cushioning of each shoe. GRF data and perceived cushioning scores were analyzed using mixed-factor (group by shoe) ANOVA. RESULTS: A significant shoe main effect was found for loading rate. Post hoc tests identified the difference between SC1 and both SC2 and SC3. The group main effect was not significant for any dependent variable. CONCLUSIONS: Results suggest that, as a group, GRF data and cushioning scores are not affected by investigator comments that do not match shoe construction characteristics. However, ratings of perceived shoe cushioning by some individual subjects reflected investigator comments and not the vertical GRF variables.
Many studies have assumed that the swing phase of human walking at preferred velocity is largely passive and thus highly analogous to the swing of an unforced pendulum. In other words, while swing-phase joint moments are generally nonzero during swing, it was assumed that they were either zero or at least negligibly small compared to gravity. While neglect of joint moments does not invalidate a study by default, it remains that the limitations of such an assumption have not been explored thoroughly. This paper makes five arguments that the swing phase cannot be passive, using both original data and the literature: (1) Computer simulations of the swing phase require muscular control to be accurate. (2) Swing-phase joint moments, while smaller than those during stance, are still greater than those due to gravity. (3) Gravity accounts for a minority of the total kinetics of a swing phase. (4) The kinetics due to gravity do not have the pattern needed to develop a normal swing phase. (5) There is no correlation between pendular swing times and human walking periods in overground walking. The conclusion of this paper is that the swing phase must be an actively controlled process, and should be assumed to be passive only when a study does not require a quantitative result. This conclusion has significant implications for many areas of gait research, including clinical study, control theory, and mechanical modeling.
STUDY DESIGN: Two-group posttest-only comparison. OBJECTIVE: To assess the influence of the Q-angle on the 3-dimensional lower-extremity kinematics during running. BACKGROUND: An excessive Q-angle has been implicated in the development of knee injuries by altering the lower-extremity locomotion kinematics. Previous investigations using 2-dimensional analyses during walking did not support this hypothesis. METHODS AND MEASURES: We hypothesized that individuals with Q-angles more than 15 degrees would display an increase in rearfoot eversion and tibial internal rotation during running. Thirty-two nonimpaired subjects (men: n = 16, mean age = 22 +/- 3 years; women: n = 16, mean age = 23 +/- 3 years) ran over ground, and 3-dimensional kinematic data were collected from the right lower extremity. Subjects with a Q-angle of 15 degrees or less comprised the low-Q-angle group, whereas those with Q-angles of more than 15 degrees comprised the high-Q-angle group. Segment and joint maximum angles and the times when the maxima occurred during stance were measured. RESULTS: The Q-angle magnitude did not increase the maximum segment or joint angles during running. The groups displayed similar maximum angles for rearfoot eversion (low Q-angle, -15.5 +/- 5.0 degrees; high Q-angle, -15.6 +/- 6.6 degrees) and tibial internal rotation (low Q-angle, -8.8 +/- 4.8 degrees; high Q-angle, -6.8 +/- 5.1 degrees). The high-Q-angle group (39.5 +/- 16.3%) achieved maximum tibial internal rotation later in the stance phase than the low-Q-angle group (28.8 +/- 10.7%). CONCLUSIONS: In support of the previous investigations involving Q-angle influences on kinematics, our study did not reveal any differences between groups in maximum joint or segment angles. The kinematic information did reveal that the high-Q-angle group displayed an increase in time to maximum tibial internal rotation. The impact of this single factor on producing knee injury is unknown.
UNLABELLED: In this paper, we are presenting an alternative approach to the investigation of lower extremity coupling referred to as a dynamical systems approach. In this approach, we calculate the phase angle of each segment and joint angle. Pairing the key segment/joint motions, we use phase angles to determine the continuous relative phase and the variability of the continuous relative phase. Data from two studies illustrate the efficacy of the dynamical systems approach. Individuals who were asymptomatic, even though they may have anatomical aberrant structural problems (i.e. high Q-angle vs low Q-angle) showed no differences in the pattern of the continuous relative phase or in the variability of the continuous phase. However, differences in the variability of the continuous relative phase were apparent in comparing individuals who were symptomatic with patellofemoral pain with non-injured individuals. Patellofemoral pain individuals showed less variability in the continuous relative phase of the lower extremity couplings than did the healthy subjects. We hypothesize that the lower variability of the couplings in the symptomatic individuals indicates repeatable joint actions within a very narrow range. RELEVANCE: We claim that the traditional view of the variability of disordered movement is not tenable and suggest that there is a functional role for variability in lower extremity segment coupling during locomotion. While the methods described in this paper cannot determine a cause of the injury, they may be useful in the detection and treatment of running injuries.
UNLABELLED: The quadriceps angle (Q-angle) has received attention as a possible predictor of patellofemoral pain (PFP). It has been suggested that an excessive Q-angle alters the patellofemoral tracking, thereby leading to PFP. Traditional methods used to evaluate alterations in lower extremity angular kinematics have not confirmed this thought. A dynamical systems approach involving segment couplings may provide additional insight by addressing the variability of the intersegmental coordination. METHODS: Thirty-two healthy pain-free subjects with varying Q-angles were examined and divided into groups based on gender and Q-angle. Subjects ran overground for 10 trials while three-dimensional kinematic data were collected from the thigh, leg, and foot. The kinematic data were digitized and filtered before a direct linear transformation was employed to calculate three-dimensional segment angles and angular velocities. The variability of the continuous relative phase (CRP) of segment couplings was used to assess between-trial consistency at specific stance phase intervals. RESULTS: No differences in CRP variability were found among subjects with varying Q-angles. Significant differences were present between the specific intervals of the couplings with the greatest variability during initial stance (P < 0.05). CONCLUSIONS: A difference in CRP variability does not appear to exist in the lower extremity between individuals with and without abnormal Q-angles. The significant differences among the stance phase intervals of running suggest the inherent presence of coordination pattern variability. The importance of the increased pattern variability during initial stance may be associated with maintaining external stability.
PURPOSE: The foot-ground impact experienced during running produces a shock wave that is transmitted through the human skeletal system. This shock wave is attenuated by deformation of the ground/shoe as well as deformation of biological tissues in the body. The goal of this study was to investigate the locus of energy absorption during the impact phase of the running cycle. METHODS: Running speed (3.83 m x s[-1]) was kept constant across five stride length conditions: preferred stride length (PSL), +10% of PSL, -10% of PSL, +20% of PSL, and -20% of PSL. Transfer functions were generated from accelerometers attached to the leg and head of ten male runners. A rigid body model was used to estimate the net energy absorbed at the hip, knee, and ankle joints. RESULTS: There was an increasing degree of shock attenuation as stride length increased. The energy absorbed during the impact portion of the running cycle also increased with stride length. Muscles that cross the knee joint showed the greatest adjustment in response to increased shock. CONCLUSION: It was postulated that the increased perpendicular distance from the line of action of the resultant ground reaction force to the knee joint center played a role in this increased energy absorption.
Two children are presented in whom thrombosis of the inferior vena cava developed in association with an acute staphylococcal osteomyelitis. One case involved the left femur and the other the left ileum. Both children had diffuse bilateral staphylococcal pneumonia from presumed septic embolization. There were close similarities between their illness and management, except that the child who survived underwent a caval thrombectomy in the acute phase of her illness. It is hypothesized that the thrombectomy played an important role in her recovery.
Although impact and shock attenuation associated with foot contact during running has been studied extensively, much less is known about these phenomena during in-line skating (ILS). The purpose of this study was to describe these impact characteristics for ILS and to test the hypothesis that there is lower impact shock during ILS than in running at preferred velocities. Subjects ran and skated on a treadmill at preferred velocity, with low-mass accelerometers attached to both the distal tibia and head. Tibia and head acceleration data during stance were used to calculate peak acceleration (PA), peak frequency (PF), and median frequency (MedF). Impact attenuation (IA) between the tibia and head was quantified by comparison of PA values and by calculating a transfer function between the head and tibia frequency spectra. PA, PF, and MedF values were significantly lower in ILS than in running for both tibial and head data, whereas ILS was similar between the two movements. The ILS condition exhibited almost no power in the frequency range between 10 and 20 Hz, which has been associated with the foot impacting the ground. It is concluded that in-line skating results in less impact shock to the body with each foot contact, and may be a useful exercise modality for those wishing to reduce impact shock during aerobic training.
The relationship between power and gross efficiency during near-maximal rowing, and physiological measures of strength, power, aerobic and anaerobic capacities and United State Rowing Association (USRA) performance tests (independent variables) was investigated among collegiate male rowers. Criterion measures of rowing power and gross efficiency were measured in a moving-water rowing tank, using an oar instrumented with strain gauges to assess force and a potentiometer to assess oar position. Bivariate correlation analysis (n = 28) indicated no relationship between the independent variables and rowing gross efficiency (P > 0.05). Rowing power [mean (SD) 483.4 (34.75) W] was significantly related to inboard leg extension strength (IL strength, r = 0.63), outboard leg extension strength (r = 0.45), combined leg extension strength (r = 0.45), and time to complete the USRA 2000-m simulated rowing race (r = -0.52; P <0.05). Stepwise regression using resampling cross-validation of 15 random samples (21 subjects per sample selected from a total group of 28 intercollegiate oarsmen) indicated that predictors of rowing power were IL strength and blood lactate following a peak oxygen uptake rowing test with significant multiple correlations of R 0.61 to 0.86 (P <0.05). The standard error of estimate (SEM) ranged from 18.1 to 29.9 W, or 5.3 (0.77) percent of the criterion value. Cross-validation with a hold-out group (seven subjects per sample) was performed for each equation and correlations ranged from R = 0.14 to 0.97 (SEM = 8.0 to 38.9 W). In conclusion, data from the present study suggest that to increase rowing power, training should emphasize leg strength and anaerobic training to decrease the level of lactate accumulated during rowing.