Ultrafast MR imaging in pediatric neuroradiology

PURPOSE

To compare the diagnostic information obtained from ultrafast MR imaging with standard MR imaging techniques in pediatric neuroradiology. The goal was to judge whether ultrafast methods can be used to replace standard methods and reduce the need for sedation or general anesthesia as a result of the considerably shorter scan times.

MATERIAL AND METHODS

Our prospective study involved 125 patients. Routine clinical imaging was performed along with two ultrafast methods. Single shot fast spin echo (SSFSE) was used to give T2-weighted images and an echo planar imaging (EPI) sequence to provide a T1-weighted images. The ultrafast images were presented to an experienced neuroradiologist who was also given the information present on the initial referral card. These reports based on the ultrafast images were then compared with the formal radiologic report made solely on the basis of the standard imaging.

RESULTS

The overall sensitivity and specificity for ultrafast imaging when compared to the reference standard were 78% and 98% with positive and negative predictive values of 98% and 76%. Pathologies characterized by small areas of subtle T2 prolongation were difficult or impossible to see on the ultrafast images but otherwise they provided reliable information.

CONCLUSIONS

This paper demonstrates that ultrafast MR imaging can diagnose many pediatric intracranial abnormalities as well as standard methods. Anatomic resolution limits its capacity to define subtle developmental anomalies and contrast resolution limitations of the ultrafast methods reduce the detection of pathology characterized by subtle T2 prolongation.

Monte-Carlo prediction of changes in areas of west Cumbria requiring restrictions on sheep following the Chernobyl accident

Following the 1986 Chernobyl accident radiocaesium levels in sheep meat in some upland areas of the United Kingdom were above the national intervention limit. West Cumbria was one of these areas and restrictions are currently still in place. In addition to deposition from the Chernobyl accident, Cumbria has been subject to radiocaesium deposition from atmospheric nuclear weapons tests, the 1957 Windscale accident and routine releases from the Sellafield nuclear reprocessing plant. A Monte-Carlo approach has been used to try to predict areas in west Cumbria where radiocaesium activity concentrations in lamb meat would require the imposition of restrictions at different times after the Chernobyl accident. The approach models the transfer of radiocaesium from soil to vegetation, based upon soil organic matter, and from vegetation to lamb meat. Spatial inputs are soil organic matter and total post-Chernobyl (137)Cs and (134)Cs deposition; a ratio of Chernobyl (137)Cs to (134)Cs deposition has been used to differentiate Chernobyl and pre-Chernobyl (137)Cs deposition. Comparisons of predicted radiocaesium transfer from soil-vegetation and the spatial variation in lamb (137)Cs activity concentrations are good and predicted restricted areas with time after Chernobyl compare well to the restricted areas set by UK government. We predict that restrictions may be required until 2024 and that in some areas the contribution of pre-Chernobyl (137)Cs to predicted lamb radiocaesium activity concentrations is significant, such that restrictions may only have been required until 1994 as a consequence of Chernobyl radiocaesium deposition alone. This work represents a novel implementation of a spatial radioecological model using a Monte-Carlo approach.

Developmental changes in plasma leptin and hypothalamic leptin receptor expression in the rat: peripubertal changes and the emergence of sex differences

Leptin, the peptide hormone product of the ob gene, regulates food intake and energy expenditure at the hypothalamic level via the long-form of the leptin receptor (Ob-Rb). Leptin also plays a key role in determining the onset of puberty, but there is controversy as to whether leptin provides a trigger for puberty or is a permissive signal. Thus, although leptin administration can advance puberty onset in rodents, circulating leptin appears stable across puberty. While these data suggest a permissive role for leptin in rat puberty, it is possible that a change in hypothalamic response to leptin (e.g. via increased Ob-Rb expression) could enhance leptin action and thus trigger puberty without a rise in circulating leptin. In the present study we assessed developmental changes in hypothalamic Ob-Rb mRNA and protein expression in female and male rats from late fetal to postpubertal life. Quantitative RT-PCR showed that Ob-Rb mRNA increased (P<0.05) by around fivefold from fetal to postpubertal life in both females and males. These increases in Ob-Rb mRNA expression were gradual, but did not increase significantly between postnatal day 30 (pre-puberty) and day 51 (post-puberty). By day 51, hypothalamic Ob-Rb mRNA expression was higher (P<0.05) in females relative to males. Hypothalamic Ob-Rb protein showed a comparable developmental pattern (approximate threefold increase from fetal to postpubertal life), although a significant increase (15%; P<0.05) was observed between days 30 and 51 in females. Plasma leptin levels exhibited a dynamic pattern in both male and female rats during the prepubertal period, characterised by a precipitous fall after birth, relative stability to day 5, then a rapid increase to a transient peak on day 12. Plasma leptin then remained unchanged from day 15 in female rats but increased in males after puberty, thus confirming the well-recognised sex difference in adult rat leptin levels. In conclusion, this study shows that developmental increases occur not only in plasma leptin but also in hypothalamic Ob-Rb expression, suggesting that both are likely to influence the timing of puberty onset. Moreover, our data show that sex differences in both hypothalamic Ob-Rb and plasma leptin emerge only after puberty.

An analysis of the environmental mobility of radiostrontium from weapons testing and Chernobyl in Finnish river catchments

The mobility of radiostrontium within the Arctic environment and surrounding area has been studied by analysing the mobility of 90Sr in river catchments that are within Finland. The environmental mobility of 90Sr deposited by both nuclear weapons testing and the Chernobyl accident has been investigated in five Finnish river catchments. Different models assessing the time-dependent mobility of 90Sr have been evaluated. No significant differences were found between the mobility of 90Sr from nuclear weapons tests and from the Chernobyl accident. Model parameters obtained by fitting to the measurements of the deposition and runoff rates of the nuclear weapons test fallout gave predictions which were consistent with the mid- and long-term contamination by the Chernobyl fallout. A comparison of 90Sr with 137Cs showed that they had similar mobility on deposition but, as time passed, the relative mobility of 90Sr increased with respect to 137Cs over a period of 5-8 years. Once the relative migration of 90Sr with respect to 137Cs reached equilibrium, its runoff rate was, on average, approximately an order of magnitude greater than 137Cs.

Modelling the long-term dynamics of radiocaesium in closed lakes

During the years after the Chernobyl accident the radioceasium activity concentration in most contaminated aquatic ecosystems decreased markedly. Lakes with no permanent inflows and outflows (closed lakes), however, still present a radioecological problem which is expected to continue for some time. In this paper, a mechanistic model for the long-term prediction of radiocaesium behaviour in closed lakes is developed. The model of Prokhorov (Radiokhimiya (Radiochemistry) 11 (1969) 317) was modified to describe the effects of bottom sediment bioturbation, surface runoff from the catchment and suspended solids formation and sedimentation. The model input parameters are the effective diffusion coefficient in bottom sediments, depth of the completely mixed layer, the distribution coefficient in the sediment-water system, the runoff coefficient, sedimentation rate, and deposition density. Values of all these parameters can be independently estimated or measured in a short-term experiment. Given negligible runoff and sedimentation, the dynamics of radiocaesium in lake water is described by a simple equation with only one unknown parameter. This allows us to make long-term predictions on the basis of a series of measurements carried out during the relatively short period. The model was tested against 137Cs activity concentrations measured between 1993 and 1999 in Svyatoe lake in the Bryansk region of Russia. Calculated and measured activity concentrations are in good agreement.

Uptake and elimination of radiocaesium in fish and the "size effect."

A number of hypotheses have previously been developed concerning the rates of uptake and elimination of radiocaesium (137Cs) in fish. These include the influence of potassium and other water chemical parameters on both uptake and elimination, and the effect of fish size on accumulation. In order to test these hypotheses, we have assembled a data set comprising more than 1,000 measurements of radiocaesium (137Cs) in predatory fish (perch, pike and brown trout) in nine European lakes during the years after Chernobyl. These data have been analysed using simple models for uptake and excretion of 137Cs in fish, showing that: 1. Fish-water concentration factors (CF) were inversely proportional to potassium [K+] concentration of the different lakes, in agreement with previous studies. 2. The uptake rate of 137Cs in fish was negatively correlated with lake [K+], but excretion rate was independent of [K+]. 3. Lower than expected CF values were found in one lake, Iso Valkjärvi, Finland. This is attributed to inhibition of the K+ (and therefore 137Cs) high affinity transport system in aquatic plants and fish by low pH and/or low Ca2+. 4. The inclusion of fish weight as a parameter in our dynamic model significantly improves the ability of the model to fit the observed measurements of 137Cs. 5. The model developed from the above hypotheses was able to fit the data from nine different lakes to within approximately a factor of 3 of the observed values.

Use of allografts in Pemberton osteotomies

SUMMARY

Twenty patients treated with 26 Pemberton osteotomies with allograft bone wedges were retrospectively evaluated radiographically. Two patients undergoing four osteotomies were excluded because of incomplete records or <1 year of follow-up. Eleven of the remaining 18 patients had other procedures performed. Osteotomies all united radiographically within 3 months. The acetabular index improved from 33 degrees before surgery to 18 degrees after surgery, and the lateral migration index improved from 60% to 26%. This new technique of Pemberton osteotomy with patellar allograft wedges allows good correction of acetabular dysplasia with immediate graft stability. This stability often obviates the need for postoperative spica casting, even for patients undergoing bilateral procedures, thereby allowing more rapid rehabilitation.

A longitudinal study of the development of low back pain in an industrial population

STUDY DESIGN

This is a longitudinal study in which industrial workers without chronic low back pain (LBP) were initially assessed with a comprehensive test battery and surveyed every 6 months thereafter for 2 years.

OBJECTIVE

To determine factors that may predispose industrial workers who lift over 5000 kg per shift to LBP.

SUMMARY OF BACKGROUND DATA

Prospective studies are small in number and often limited in breadth or depth of the test battery, methodologic issues, or investigator expertise. There are no prospective studies that focus on a homogeneous work sample of industrial employees.

METHODS

Production workers (n = 149) who volunteered for the 2-year study were assessed using physical measures (e.g., muscular strength, endurance, and flexibility), lifting kinematics (a sagittal plane box lift), and health, lifestyle, and work environment data (paper questionnaires). Follow-up questionnaires were distributed every 6 months for 2 years.

RESULTS

Using self-report of LBP as the main outcome measure, eight variables predicted LBP in this sample with a 75% correct prediction rate. Predictor variables included age, thoracic acceleration during the trunk velocity test, median frequency intercept of electromyography of the right L3 erector spinae, quadriceps strength, quadriceps endurance, self-assessment of fitness, having a confidante, and number of medications currently taken.

CONCLUSION

Results confirmed the multifactorial nature of low back pain and suggest that personal fitness is an important defense against low back pain, even in manual handling lifting tasks.

Decision points in the integrative research review process: a flow-chart approach

With the ever increasing volume of research information appearing in the literature, research syntheses are becoming more popular among researchers in various disciplines. This phenomenon demands application of rigorous and systematic review methodologies. Using Cooper's five-stage process for conducting an integrative research review, the authors have constructed a flow chart for health sciences librarians and others using this approach to identify decision points in this process. The accompanying narrative details the information that must be considered and analyzed. Included in the flow chart and text is an elaboration of meta-analysis and an integrative review to accommodate both quantitative and qualitative research results. A case is made for a collaborative relationship between the researcher and the librarian.

Children in group homes: family dynamics, adolescent suicide attempts and drug use

Three hundred children age 10-20 living in group homes for children were assessed for behaviors related to alcohol and other drug consumption, suicide attempts, frequency of punishment, attention from parents, conflicts with parents, and other family dynamics. Children who used substances were significantly more likely to have attempted suicide more frequently. Children who had attempted suicide were more likely to perceive that they had not received enough parental attention, to have had more conflicts with parents, and to have run away from home. This seminal article indicates inter-related prevalences of family factors, suicide and substance abuse issues and suggests the need for strong institutional and agency policy development for this understudied "at risk" population.

A critical review of measures to reduce radioactive doses from drinking water and consumption of freshwater foodstuffs

Following a radioactive fallout event, there are a number of possible intervention measures to reduce radioactive doses to the public via the surface water pathway. We have critically reviewed the options available to decision-makers in the event of radioactive contamination of surface waters. We believe that the most effective and viable measures to reduce radioactivity in drinking water are those which operate at the water treatment and distribution stage. Intervention measures to reduce concentrations of radioactivity in rivers and reservoirs are expected to be much less viable and efficient at reducing doses via the drinking water pathway. Bans on consumption of freshwater fish can be effective, but there are few viable measures to reduce radioactivity in fish prior to the preparation stage. Lake liming and biomanipulation have been found to be ineffective for radiocaesium, although the addition of potassium to lakewaters appears promising in some situations. Lake liming may be effective in reducing radiostrontium in fish, though this has not, to our knowledge, been tested. De-boning fish contaminated by strontium is probably the most effective food preparation measure, but salting and freezing can also reduce radiocaesium concentrations in fish. The provision of accurate information to the public is highlighted as a key element of countermeasure implementation.

Determination of radionuclide exchangeability in freshwater systems

Two freshwater sediments were spiked with 57Co, 85Sr and 134Cs and left for adsorption times ranging from 1 day to over 60 days. Following adsorption, the 'exchangeable' pool of each radionuclide was measured using ammonium acetate extractions and a sequential leach procedure (Tessier et al., 1979), and the results were compared. Exchangeability was found to depend upon the sediment, radionuclide, sorption time and the identity of extracting agent. All three radionuclides showed a shift with increasing adsorption time from regular exchange sites to sites which are sterically hindered, but a fixation within the sediment was only observed for 57Co and 134Cs, with similar ammonium acetate extraction yields for both radionuclides. Misleading results were obtained during the sequential leach procedure due to redistribution and, therefore, the inclusion of a NH4+ leach after the MgCl2 extraction step was suggested. A mathematical model of element speciation was fairly successful at defining the 'exchangeable' fraction, suggesting that the chemically- and mathematically-defined fractions were similar.

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.