A comparison of the effects of patient-controlled analgesia with intravenous opioids versus Epidural analgesia on recovery after surgery for idiopathic scoliosis

STUDY DESIGN

Epidural infusion was compared with standard patient-controlled analgesia (PCA) in 50 patients after surgical correction of adolescent idiopathic scoliosis with respect to certain postoperative parameters.

OBJECTIVES

To compare postoperative parameters after posterior spinal instrumentation and fusion (PSIF) and to determine whether epidural infusion prolongs hospital stay or increases the risk of complications.

SUMMARY OF BACKGROUND DATA

Patient-controlled analgesia and epidural infusion are both safe and effective in controlling postoperative pain after PSIF. One criticism of epidural infusion has been longer hospital stays. No study was found in the literature in which PCA was compared with epidural infusion.

METHODS

The records of 50 consecutive patients who had undergone PSIF were reviewed. The epidural group consisted of 30 patients and the PCA group 20. Age, weight, degree of curve, and levels fused were evenly matched. Postoperative parameters including the day that each patient tolerated a full diet, day of independent ambulation, length of hospital stay, and pain control were compared.

RESULTS

Pain control was comparable in each group. The epidural group tolerated a full diet earlier and on average were discharged 0.5 days sooner than the PCA group. Both differences are statistically significant. No significant complications were reported in either group.

CONCLUSIONS

Epidural infusion of opioids with bupivacaine is safe and effective for controlling postoperative pain after PSIF without an increased complication rate when compared with PCA. In the current study, patients tolerated a full diet and were discharged from the hospital an average of 0.5 days earlier than PCA-treated patients.

A prospective evaluation of the timing of postoperative radiotherapy for preventing heterotopic ossification following traumatic acetabular fractures

PURPOSE

Preoperative and immediate postoperative irradiation of traumatic acetabular fractures (TAF), although known to reduce heterotopic ossification (HO), can cause significant organizational and logistic difficulties. We sought to determine an acceptable time interval between surgery and radiation without compromising control, as well as to update our large experience and to further validate our treatment philosophy.

METHODS AND MATERIALS

Beginning in June 1995, we began a prospective study, irradiating 152 patients on postoperative days 1, 2, or 3. There were also 17 patients delayed further secondary to medical difficulties.

RESULTS

All patients treated since June 1995 received 700 cGy/1 fx. Fifty-eight patients received radiation within 24 hours of surgery, 41 within 2 days, 53 within 3 days, 13 within 4 days, and 4 were delayed further. Delaying irradiation for up to 4 days postoperatively caused no statistical increase in HO (p = 0.625). Of 263 patients in our retrospective cohort, HO occurred in 5.3% of patients who received irradiation versus 60% of patients who did not.

CONCLUSION

In our prospective study, we noted no perceptible increase in HO with up to a 3-day interval between surgery and radiotherapy. This allows a more structured treatment schedule and allows the patient more time to heal and recover. Updated results from our overall series continue to demonstrate that adjuvant radiation decreases the incidence and severity of HO after TAF.

Exercise induces isoform-specific increase in 5'AMP-activated protein kinase activity in human skeletal muscle

The 5'AMP-activated protein kinase (AMPK) is stimulated by contractile activity in rat skeletal muscle. AMPK has emerged as an important signaling intermediary in the regulation of cell metabolism being linked to exercise-induced changes in muscle glucose and fatty acid metabolism. In the present study, we determined the effects of exercise on isoform-specific AMPK activity (alpha1 and alpha2) in human skeletal muscle. Needle biopsies of vastus lateralis muscle were obtained from seven healthy subjects at rest, after 20 and 60 min of cycle ergometer exercise at 70% of VO(2)max, and 30 min following the 60 min exercise bout. In comparison to the resting state, AMPK alpha2 activity significantly increased at 20 and 60 min of exercise, and remained at a higher level with 30 min of recovery. AMPK alpha1 activity tended to slightly decrease with 20 min of exercise at 70%VO(2)max; however, the change was not statistically significant. AMPK alpha1 activities were at basal levels at 60 min of exercise and 30 min of recovery. On a separate day, the same subjects exercised for 20 min at 50% of VO(2)max. Exercise at this intensity did not change alpha2 activity, and similar to exercise at 70% of VO(2)max, there was no significant change in alpha1 activity. In conclusion, exercise at a higher intensity for only 20 min leads to increases in AMPK alpha2 activity but not alpha1 activity. These results suggest that the alpha2-containing AMPK complex, rather than alpha1, may be involved in the metabolic responses to exercise in human skeletal muscle.

Increased fetal glucocorticoid exposure delays puberty onset in postnatal life

The fetal environment is now recognized as a key determinant of the adult phenotype, being linked to development of diseases, including hypertension, as well as the timing of puberty. Such links may be related, in part, to the level of fetal exposure to maternal glucocorticoids in utero, which is normally regulated by placental expression of the enzyme 11beta-hydroxysteroid dehydrogenase (11beta-HSD). The present study examined whether manipulation of fetal glucocorticoid exposure, either directly or indirectly via 11beta-HSD inhibition, influences the subsequent timing of puberty. Administration of dexamethasone acetate at low (LDEX, 0.25 microg/ml drinking water) or high doses (HDEX, 1 microg/ml) or carbenoxolone (CBX, 2 x 10 mg/day, sc; an inhibitor of 11beta-HSD) to pregnant rats from day 13 to term (day 23) reduced offspring birthweight (LDEX: 9%; HDEX: 27%; CBX: 8%) and resulted in a subsequent delay in the onset of puberty in females (control: 41.4 +/- 0.5; LDEX: 44.8 +/- 0.7; HDEX: 48.5 +/- 0.4; CBX: 43.6 +/- 0.5 days). Importantly, the effects of CBX were not observed in the absence of maternal adrenals, indicating that they were mediated by increased fetal exposure to endogenous maternal glucocorticoids. In contrast, maternal treatment with metyrapone (MET; an inhibitor of glucocorticoid synthesis; 500 microg/ml drinking water from day 13) increased birthweight by 5% and advanced puberty onset in male offspring (control: 48.8 +/- 1.0; MET: 45.7 +/- 0.8 days). Changes in the timing of puberty onset were not attributable to changes in either bodyweight at puberty or peripubertal plasma leptin concentrations. Peripubertal plasma LH was also unaffected in animals with delayed puberty but was elevated in male offspring of MET-treated mothers. Collectively, these results demonstrate that fetal glucocorticoid exposure is an important determinant of the timing of puberty onset in postnatal life, and that this effect is operable within the normal physiological range of glucocorticoid concentrations.

An enantiomeric assay for the flavonoids medicarpin and vestitone using capillary electrophoresis

An enantiomeric assay for the flavonoids vestitone and medicarpin from transgenic plant extracts was developed using capillary electrophoresis. It was found that no single cyclodextrin proved capable of resolving the enantiomers of both medicarpin and vestitone. Instead, hydroxypropyl-beta-cyclodextrin provided the best selectivity for the vestitones while hydroxypropyl-gamma-cyclodextrin was best for the medicarpins. The addition of organic modifiers improved the resolution of both enantiomers. Acetonitrile proved best for the vestitones and only methanol improved the resolution of the medicarpins. An optimization study of mixed hydroxypropyl-beta-cyclodextrin and hydroxypropyl-gamma-cyclodextrin containing electrolytes revealed that the separation of the medicarpin enantiomers was intolerant to the presence of hydroxypropyl-beta-cyclodextrin. Our optimized running electrolyte was composed of 2 mM hydroxypropyl-beta-cyclodextrin, 20 mM hydroxypropyl-gamma-cyclodextrin, and 25 mM borate at pH 10.0 with 10% v/v methanol. This system provided a resolution of 1.47 and 1.80 for the medicarpin and vestitone enantiomers, respectively. This analysis was completed in 12 min. This separation provided a rapid screen to determine the enantiomeric purity of key flavonoids biosynthesized by transgenic legumes.

Recent advancements in amino acid analysis using capillary electrophoresis

Recent advances in the analysis of amino acids using capillary electrophoresis are addressed. This area of research continues to receive increased attention as is evident from the 62 references reviewed. This review discusses current detection strategies including UV absorbance, laser-induced fluorescence, electrochemical, and others. Separation methodologies for both derivatized and underivatized amino acids are reviewed. Both direct and indirect enantiomeric resolution of amino acids are addressed. Applications utilizing capillary electrophoresis for the analysis of amino acids are discussed. This review covers literature published in 1997 and 1998.

Explorations of alkyl polyols as "class I" organic modifiers to adjust selectivity in micellar electrokinetic capillary chromatography

In this study, we investigated a novel series of micelle modifiers useful to alter selectivity in micellar electrokinetic capillary chromatography (MEKC). These modifiers were alkyl polyalcohols, including 1-octanol, 1,2-octanediol, 1,2,3-octanetriol, 1,2-hexanediol, and 1,2-butanediol, which act as class I organic modifiers in that their effects are on the sodium dodecyl sulfate (SDS) micelle rather than the surrounding aqueous phase. This characteristic allows the alkyl polyols to effect resolution when applied at concentrations as low as 20 mM (0.25% v/v) by altering the selectivity observed with SDS without a modifier. The effects of the alkyl polyols on the critical micelle concentration of SDS, electroosmotic flow, and electrophoretic mobility of the SDS micelle are presented. These modifiers had little impact on the migration time window at the concentrations explored. Changes in selectivity induced by the alkyl polyols for a large set of model compounds are presented. Trends indicate that solutes capable of forming hydrogen bonds tend to decrease their interactions with the micellar phase while nonhydrogen bonding solutes increase their interactions upon addition of the modifiers. The solvation parameter model was used to characterize the induced changes in selectivity. This model suggests that even though the modifiers are structurally similar, each produced a unique set of system constants. It was also demonstrated that the addition of alkyl polyols improved the correlation between the partition coefficients of SDS and water to 1-octanol and water. The usefulness of the alkyl polyols was demonstrated by examining their effects on the separation of 11 priority phenols.

Does pediatric orthopedic subspecialization affect hospital utilization and charges?

In the current climate of health care reform, there is a perception that overspecialization is responsible for increased medical costs. Few studies support the premise that high-quality surgical subspecialization improves the cost effectiveness of care. The purpose of this study was to compare hospital utilization and charges between a pediatric hospital staffed by pediatric orthopedic subspecialists and a community hospital system for the care of closed femur fractures and slipped capital femoral epiphysis (SCFE) in a pediatric population. We reviewed hospital charges and length-of-stay (LOS) data for all children treated for closed femoral shaft fractures and SCFE between 1992 and 1994 within the Intermountain Health Care System (IHC). Within the IHC, there are 23 community hospitals and one children's hospital (PCMC). Patients were matched for age and injury severity. Four of six orthopedic surgeons at PCMC are pediatric orthopedists, but none of the community orthopedists has subspecialty training in pediatric orthopedics. For closed femoral shaft fractures (n = 334), the average hospital charges were less (PCMC, $4,943/Other IHC, $9,031), and length of stay was shorter (PCMC, 2.81 days/Other IHC, 8.91 days) when the child was treated at the children's hospital by pediatric orthopedic subspecialists. For SCFE (n = 63), the average hospital charges were less (PCMC, $2,824/Other IHC, $3,544) and the length of stay was shorter (PCMC, 1.13 days/Other IHC, 1.64 days) at the children's hospital. These data suggest that hospital utilization and charges were significantly decreased if the care was provided by pediatric orthopedic subspecialists in a children's hospital.

Adjusting selectivity in micellar electrokinetic capillary chromatography with 1,2-hexanediol

In this report, we introduce a new micelle modifier useful to alter selectivity in micellar electrokinetic capillary chromatography (MECC). 1,2-Hexanediol acts as a class I organic modifier in that its effects are on the sodium dodecyl sulfate (SDS) micellar rather than the surrounding aqueous phase. This characteristic allows 1,2-hexanediol to improve resolution when applied at concentrations as low as 20 mM (0.25% v/v) by altering the selectivity observed with SDS alone. The effects of 1,2-hexanediol on the critical micelle concentration of SDS, electroosmotic flow, electrophoretic mobility of the SDS micelle, and reproducibility are presented. 1,2-Hexanediol had little impact on the migration time window at concentrations below 100 mM. Changes in selectivity induced by 1,2-hexanediol for a large set of model compounds are presented. Analytes capable of forming hydrogen bonds tend to decrease their interactions with the micellar phase while nonhydrogen bonding analytes increase their interactions. The usefulness of 1,2-hexanediol was demonstrated by examining its effects on the separation of dansylated amino acids. Eighteen of twenty amino acids could be separated with a resolution greater than 1.6 within 1600 s using a combination of 1,2-hexanediol and isopropanol.

Trauma patients with multiple extremity injuries: resource utilization and long-term outcome in relation to injury severity scores

BACKGROUND

Trauma patients with multiple extremity injuries (MEI) make heavy demands on hospital resources and face long-term difficulties in rehabilitation, yet the literature contains little about their treatment as a distinct group.

METHODS

In this study, a cohort of 54 patients with MEI, all treated at a Level I trauma center, was compared with a trauma control (TC) group that had major injuries not focused at the extremities (but excluding patients with neurologic sequelae of head or spinal cord injuries). Demographic features, primary measures reflecting utilization of hospital resources, return-to-employment and productivity data, and health-related quality of life scores (Medical Outcomes Study 36-Item Short Form Health Survey [SF-36]) were compared.

RESULTS

Although mean Injury Severity Scores (ISS) for the MEI and TC groups were almost identical (16.2 and 17.4, respectively), the patients with MEI had a mean hospital stay almost twice as long (25 vs. 13 days) and had double the resource intensity weight compared with the TC group. After discharge, the trend of the MEI group was to greater long-term disability, based on SF-36 scores, and lower "return to productivity" figures. The ISS did not predict the greater demands on resources made by the MEI group relative to our TC group. Main injury severity scores for the extremities were more predictive than the ISS for length of hospital stay and the SF-36 concepts at the 2-year follow-up evaluation.

CONCLUSION

The study emphasizes the need for injury scoring systems that better predict the needs of patients with MEI and that will serve as a basis for equitable funding of trauma centers.

Postoperative epidural analgesia for pediatric spine surgery

The safety of epidural infusion for postoperative analgesia in pediatric spine surgery continues to be established. A continuous epidural infusion of morphine sulfate and bupivacaine was used for postoperative analgesia in 12 pediatric patients undergoing spinal surgery. The epidural was placed intraoperatively by the operating surgeon, while continuous infusion was managed postoperatively by a pediatric anesthesiology pain service team. In addition to the continuous infusion, 2 of the 12 also were provided on-demand patient-controlled boluses via epidural catheter for breakthrough pain. Patients experienced analgesia as documented by a comprehensive pain scale form. No catheters failed, while side effects were minimal and easily managed. These results provide confirmation of the safety and efficacy of continuous epidural infusion for postoperative analgesia following pediatric spine surgery and evidence that patient-controlled epidural analgesia is an option.

A comparison of manual versus computer-assisted radiographic measurement. Intraobserver measurement variability for Cobb angles

STUDY DESIGN

A comparison between computer-assisted measurement using digitized radiographs, which has the potential to reduce error, and manual measurement using standard radiographs.

OBJECTIVE

To assess measurement variability for the Cobb method on digital radiographs and compare it with that of manual measurements on standard radiographs.

BACKGROUND DATA

Studies of the Cobb method have demonstrated multiple sources of error leading to significant intraobserver measurement variability. Estimates for the 95% confidence interval for intraobserver variability range from 2.8 degrees to 10 degrees.

METHODS

Twenty-four scoliosis radiographs were measured by six examiners. Two measurement sets were done manually ("manual set"), and two measurement sets were done on digitized images using a computer mouse ("computer set").

RESULTS

For the manual set, the 95% confidence interval for intraobserver variability was 3.3 degrees (range, 2.5-4.5 degrees). For the computer set, the value was 2.6 degrees (range, 2.3-3.3 degrees). This difference in 95% confidence intervals between the manual and computer sets was statistically significant (P < 0.001).

CONCLUSIONS

The results of this study demonstrate that intraobserver variability for manual and computer Cobb angle measurements yield a 95% confidence interval of approximately 3 degrees, with the computer having a slightly lower variability. The computer technique removes sources of intrinsic error, e.g., the variability introduced by using different manual protractors, the inaccuracy of standard protractors, and the use of wide-diameter radiographic markers. Identical digital images can be shared electronically between centers, without having to duplicate and mail films. Multicenter studies in which different examiners will be measuring Cobb angles may consider using the computer as a measuring device to reduce intrinsic measurement errors.

Use of a satellite-derived land cover map to estimate transport of radiocaesium to surface waters

During the weeks to months after the deposition of radioactive fallout, the initial concentration of radioactivity in rivers and lakes declines as a result of flushing and removal to bottom sediments. In the long-term, however, radioactivity in the water body can remain at significant levels as a result of secondary contamination processes. In particular, it is known that soils contaminated by long-lived radionuclides such as 137Cs and 90Sr provide a significant source to surface waters over a period of years after fallout. Using The Land Cover Map of Great Britain, a satellite-derived land cover map as a surrogate indicator of soil type, we have related catchment land cover type to long-term 137Cs activity concentrations in 27 lakes in Cumbria, UK. The study has shown that satellite-derived maps could be used to indicate areas vulnerable to high long-term 137Cs transport to surface waters in the event of a nuclear accident. In these Cumbrian lakes, it appears that residual 137Cs levels are determined by transfers of 137Cs from contaminated catchments rather than within-lake processes. Only three of the cover types, open shrub moor, bog and dense shrub moor, as identified by the satellite, are needed to explain over 90% of the variation in long-term 137Cs activity concentrations in the lakes, and these have been shown to correlate spatially with occurrence of organic soils.

Developments in amino acid analysis using capillary electrophoresis

The current status in the analysis of amino acids using capillary electrophoresis is addressed. This area of biological analysis has received increased attention with more than 200 articles being published in the last five years. This review discusses pre-, post-, and on-column derivatization techniques used to tag amino acids providing a detectable moiety. Several separation methodologies which provided resolution for large sets of amino acids are presented. An overview of advances in the enantiomeric resolution methodologies for amino acids is given. Both direct and indirect enantiomeric separation schemes are summarized. Recent advances in detection strategies for both derivatized and underivatized amino acids are presented. Applications utilizing amino acid analysis by capillary electrophoresis are described. This review covers articles published between 1991 and 1996.

Towards a generalized model for the primary and secondary contamination of lakes by Chernobyl-derived radiocesium

As part of the UK Ministry of Agriculture Fisheries and Food Directorate of Fisheries Research (MAFF/DFR) post-Chernobyl monitoring program, a detailed study was carried out of the change over time in dissolved-phase 137Cs concentrations in a number of lakes in Cumbria, UK. These measurements have been combined with published data on 137Cs in Cumbrian and other European lakes in order to develop and test a "double exponential" model for changes in lakewater concentrations: A exp(-k1t) + B exp(-k2t) where the exponential terms correspond, respectively, to the initial fast flush of activity through the system followed by longer-term transfers (timescale, years) from the catchment. Parameter values have been determined for this model by curve-fitting to the set of measurements of post-Chernobyl 137Cs activities in lakes. Values of fitted parameters are shown to be related, in a simple manner, to the physical characteristics of the system, in particular water residence time and mean lake depth. These parameters are generalized to give a simple empirical model for the full set of study lakes. The model is shown to give estimates of 137Cs activity to within a factor of 5 of field data for a period of several years after the fallout. Initial fractional losses of activity from catchment to lake were determined to be within the range 0.44-8.7% per year, declining exponentially with a mean rate constant 0.98 x 10(-3) d(-1).

The predictive value of the development of the acetabular teardrop figure in developmental dysplasia of the hip

We reviewed the radiographs of 72 hips, 47 with developmental dysplasia of the hip (DDH), and 25 normal hips, to determine the timing of the normal appearance of the acetabular teardrop figure and the value of teardrop development after reduction of the hip in predicting outcome. In normal hips, all children had a teardrop figure by age 18 months. In the 47 hips with DDH, no teardrop figure appeared until the hip was reduced. The DDH hips were divided into two groups based on the success of the initial reduction. By using statistical analysis, we found that the appearance of the acetabular teardrop within 6 months after reduction of the hip is strongly associated with a favorable long-term outcome. We believe that the appearance of the teardrop is the earliest radiographic sign that a stable, concentric reduction of the hip has been achieved.

Methods for assessing the effects of drugs on gastrointestinal function in patients and healthy volunteers

The gastrointestinal tract is a complex organ with many functions. Many diseases affect the way in which the gastrointestinal tract performs these functions. The pharmaceutical industry and academia are putting great effort into the development of treatments for these diseases. As a consequence, there is increasing pressure on the clinical pharmacologist and gastroenterologist to develop methods to measure the effects of drugs on the gastrointestinal tract. This article reviews the methods currently available to assess gastrointestinal function; in particular it focuses on motility and sensitivity.

Mobility of Chernobyl-derived 137Cs in a peatbog system within the catchment of the Pripyat River, Belarus

The behaviour of Chernobyl-derived 137Cs in a hydrologically isolated bog system in the catchment of the Pripyat River, Belarus was investigated. Measurements were made of 137Cs activities in the solids and pore waters of the bog soils, as well as the variability in activity in water draining from the bog. It was found that the radiocaesium activity of the pore water, and hence the measured distribution coefficient, Kd, was dependent upon the pressure at which the water was removed from the soil. Measured values of Kd were of the order 10(2) l/kg at an extraction pressure of 0.8 MPa, approximately one order of magnitude lower than those measured in a similar system, Devoke Water, in the UK [1]. Results of comparative measurements suggested that this was a result of the different pore water extraction techniques used. The vertical migration of radiocaesium was modelled using a solution of the advection-diffusion equation. Using a mass balance approach, it was estimated that 137Cs was removed from the system at a rate of 0.3% of the catchment inventory per year, approximately 8 years after the Chernobyl accident. It was shown that both vertical migration and removal of 137Cs is best modelled using a Kd based on a measurement of pore water held at low pressure in the soil, approximately 10(3) l/kg. 137Cs activities in soil pore waters and in drainage waters were very strongly related to the aqueous potassium concentration, and both showed concentration minima in drainage water during the spring. It was shown that runoff coefficients of radiocaesium from peat bogs 8 years after the Chernobyl accident were approximately one order of magnitude greater than those from unsaturated soils of higher mineral content.

Benign soft-tissue lesions in children

This article is a review of the common benign soft-tissue lesions of the spine and extremities. Reviewed are the pathophysiology, natural history, appropriate work-up, and treatment options. A recommendation is given to consider the diagnosis as possible malignancy and approach such lesions with caution.

Influence of temperature on mutational resistance to 4-quinolones

Minimum inhibitory concentration (MIC) values of ciprofloxacin (CAS 85721-33-1), ofloxacin (CAS 82419-36-1) or levofloxacin (CAS 100986-85-4) against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis were determined at 37, 30 and 25 degrees C on nutrient agar. With E. coli and S. aureus, reducing the incubation temperature from 37 to 30 to 25 degrees C decreased the MIC values for each drug. With P. aeruginosa, temperature reduction also decreased the MIC values for ciprofloxacin but increased the MICs for ofloxacin or levofloxacin. With S. epidermidis, temperature reduction increased the MICs for ciprofloxacin and ofloxacin but with levofloxacin the MICs were identical at 37 or 25 degrees C but higher at 30 degrees C. Mutants of these bacterial species were selected on nutrient agar containing five times their respective MICs of the 4-quinolones at 37, 30 and 25 degrees C. with S. epidermidis, temperature reduction always reduced its mutation frequency to resist 4-quinolones, whereas with the other three species the effect of temperature was more variable, and in some instances even elevated their mutation rates.

Gender differences in performance of a selection test using the incremental lifting machine

The purpose of the study was twofold: (1) to examine any gender differences in the performance of a pre-employment selection test using the incremental lifting machine (ILM); and (2) to formulate recommendations regarding analyses of selection fairness in studies of pre-employment screening tests and devices. Data were collected in a series of studies designed to permit analyses of: (1) dynamic measures derived for a 1.8 m maximum ILM strength test; (2) relationships between ILM test scores and performance of a maximal box-lifting task using three different protocols; (3) the impact of anthropom trie measures on performance of both test and task; (4) prediction of actual task performance; and (5) accuracy of the ILM screening test for three different cut-off standards. Results revealed that females differed significantly from males in their performance of a 1.8 m maximum ILM strength test in terms of timing, displacement, velocity, acceleration, force and power. Maximum ILM scores attained by females were poorly correlated with maximum box-lifting scores, but they were significantly related to body weight. Also, regression analyses based on ILM scores and associated dynamic parameters accounted for twice as much variance in box-lifting scores for males than for females. Furthermore, the use of cut-off standards of 22.7 kg and 27.3 kg produced a percentage of false negative results for females (12% and 32% respectively), but not for males. Also, for the cut-off level of 27.3 kg, female selection rates were only 56% of the selection rates for males. Issues for future investigation are recommended.

Combination trochanteric arrest and intertrochanteric osteotomy for Perthes' disease

A significant complication associated with femoral varus osteotomy (FVO) is trochanteric overgrowth and concomitant abductor weakness. We identified 28 patients who underwent unilateral FVO for Perthes' disease, had a healed femoral head on their latest radiograph, and had at least 2.1 years of follow-up. The patients were divided into two groups; group 1: patients who did not receive prophylactic trochanteric arrest (TA) at the time of FVO; group 2: patients who did receive TA. Clinical parameters were quantified using objective measurements and a scoring system for reported symptoms. At postoperative follow-up, group 2 had greater articulotrochanteric distance (ATD), better range of motion, less abductor weakness, less pain, and superior activity levels. These differences were statistically significant. This study demonstrates that when properly performed with respect to indications and timing, the combination of TA and FVO provides an effective means of managing Perthes' disease when "head at risk" signs are present. The authors include a detailed discussion of surgical technique.

Rapid determination of logarithmic partition coefficients between n-octanol and water using micellar electrokinetic capillary chromatography

Micellar electrokinetic capillary chromatography (MECC) was evaluated as a rapid screening tool for the determination of logarithmic partition coefficients between n-octanol-water (log P(OW)). The technique is performed by electrochromatographing a mixture of standards of known log P(OW). The logarithmic capacity factor of each standard was plotted against its log P(OW) to form a linear calibration curve for a given set of chromatographic conditions. The log P(OW) of an unknown is calculated by using its chromatographically determined capacity factor and extracting the log P(OW) value from the calibration curve. The method was evaluated with a set of model compounds with known log P(OW). The accuracy of the method was examined and found to be within the limits required for screening purposes. The correlation of log P(OW) values determined using HPLC and MECC for some novel compounds was examined. This technique allows the screening of log P(OW) at a rate of four samples per hour with minimal sample requirements (< microgram) and with extremely small solvent waste generated.