Acetabular fractures. Clinical outcome of surgical treatment

Sixty patients with acetabular fractures were treated surgically. All fractures were a result of high energy trauma, most with significant associated injuries. Fifty-three of the patients were followed up for at least 2 years. Clinical outcome was analyzed clinically using the Harris hip score and radiographically. In 41 (77.4%) of the patients, the surgical procedure was judged successful (Harris hip score greater than 80 points). Three factors were found to be statistically significant predictors of such an outcome: patient age younger than 40 years; simple fractures based on the classification of Letournel and Judet; and absence of damage to the femoral head. Possible influential factors that were not found to be statistically significant in this population included additional injuries, immediate complications, quality of reduction, heterotopic ossification, ipsilateral femoral fracture, and sciatic nerve damage. Open reduction and internal fixation of the displaced acetabular fracture, although a demanding procedure, can result in a satisfactory clinical outcome given a consistent approach with a dedicated team.     

Individualized feedback of volatile agent use reduces fresh gas flow rate, but fails to favorably affect agent choice

BACKGROUND: Cost reduction has become an important fiscal aim of many hospitals and anesthetic departments, despite its inherent limitations. Volatile anesthetic agents are some of the few drugs that are amenable to such treatment because fresh gas flow rate (FGFR) can be independent of patient volatile anesthetic agent requirement. METHODS: FGFR and drug use were recorded at the temporal midpoint of 2,031 general anesthetics during a 2-month preintervention period. Staff and residents were provided with their preintervention individual mean FGFR, their peer group mean, and educational material regarding volatile agent costs and low-flow anesthesia. FGFR and drug use were remeasured over a 2-month period (postintervention) immediately after this information (N = 2,242) and again 5 months later (delayed follow-up), for a further 2-month period (N = 2,056). RESULTS: For all cases, FGFR decreased from 2.4+/-1.1 to 1.8+/-1.0 l/min (26% reduction) after the intervention and increased to 1.9+/-1.1 l/min (5% increase of preintervention FGFR) at the time of delayed follow-up. Use of more expensive volatile agents (desflurane and sevoflurane) increased during the study period (P < 0.01). In a subgroup of 44 staff members with more than five cases in all study periods, 42 members decreased their mean FGFR after intervention. At delayed follow-up, 30 members had increased their FGFR above postintervention FGFR but below their initial FGFR. After accounting for other predictors of FGFR, the effectiveness of the intervention was significantly reduced at follow-up (28% reduction), but retained a significant effect compared to preintervention FGFR (19% reduction). CONCLUSIONS: Although individual feedback and education regarding volatile agent use was effective at reducing FGFR, effectiveness was reduced without continued feedback. Use of more expensive volatile agents was not reduced by education regarding drug cost, and actually increased.     

Combined injuries to the lower limbs

Several patterns of severe lower limb injuries are presented. They all indicate high energy trauma and affect the immediate care of the patient. The improvement of evacuation systems and resuscitating methods in intensive care create many reconstruction challenges for the orthopaedic surgeon. Awareness of the different combinations which are presented can serve as a tool that may be helpful in these demanding injuries. Guidelines for management of combined injuries are essential to improve the outcome of these life-threatening situations.     

Avascular necrosis after treatment of DDH: the protective influence of the ossific nucleus

We retrospectively reviewed the results of open or closed reduction for developmental dysplasia of the hip (DDH) in 49 children younger than 12 months old, who had 57 hip dislocations. Group A (18 hips) developed partial or complete avascular necrosis (AVN), and group B (39 hips) did not develop AVN. Thirty-eight hips were treated by closed reduction, and 17 had open reduction. One patient with bilateral hip dislocation initially had closed reductions followed by bilateral open reduction 3 months later. With the numbers available for study, there was no significant difference in the occurrence of AVN with respect to variables such as preliminary traction, closed versus open reduction, Pavlik harness use, and age at the time of operative intervention. However, the presence of the ossific nucleus before reduction, detected either by radiographs (p < 0.001) or ultrasonography (p = 0.033) was statistically significant in predicting AVN. Only one (4%) of 25 hips with an ossific nucleus developed AVN, whereas 17 (53%) of 32 hips without an ossific nucleus before reduction developed AVN. Our results suggest that the presence of the ossific nucleus before closed or open reduction for DDH may decrease the risk of AVN.     

Dynamic changes in sensitivity occur during the acute response to cocaine and methylphenidate

Rationale: We have previously shown that during the acute response to amphetamine, a stimulant that released dopamine, behavioral sensitivity to the drug undergoes dynamic changes, as evident in the altered behavioral profile expressed to the subsequent administration of a low dose of the drug. Objective: The present studies were designed to determine if these dynamic changes in sensitivity occur with amphetamine-like stimulants that act primarily by blocking dopamine uptake. Methods: Groups of animals were primed with 40 mg/kg cocaine or 30 mg/kg methylphenidate, then during the acute response, a low, locomotor-stimulant dose of amphetamine (1.5 mg/kg) was administered to probe for changes in sensitivity. Conversely, to determine whether the manifestation of the increased responsivity is idiosyncratic to amphetamine, animals were also primed with amphetamine (4 mg/kg), then probed with low doses of cocaine (10 and 20 mg/kg) or methylphenidate (10 mg/kg). Parallel microdialysis studies were performed to assess the caudate-putamen and nucleus accumbens extracellular dopamine responses. Results: Priming with the uptake blockers each resulted in a stereotypy response to the subsequent low-dose amphetamine probe. Likewise, after priming with amphetamine, the uptake blockers each induced a pronounced stereotypy response. In each case, these changes in behavioral responsivity were expressed in the absence of corresponding changes in the probe-induced regional dopamine responses. Conclusions: Dynamic changes in behavioral sensitivity during the response to acute stimulant administration are a characteristic common to both dopamine releasers and uptake blockers. These rapid changes in sensitivity may contribute to the behaviors associated with binge patterns of drug abuse. Received: 5 April 1999 / Final version: 28 May 1999     

The redshift-distance relation

Key predictions of the Hubble law are inconsistent with direct observations on equitable complete samples of extragalactic sources in the optical, infrared, and x-ray wave bands-e.g., the predicted dispersion in apparent magnitude is persistently greatly in excess of its observed value, precluding an explanation via hypothetical perturbations or irregularities. In contrast, the predictions of the Lundmark (homogeneous quadratic) law are consistent with the observations. The Lundmark law moreover predicts the deviations between Hubble law predictions and observation with statistical consistency, while the Hubble law provides no explanation for the close fit of the Lundmark law. The flux-redshift law F [symbol, see text] (1 + z)/z appears consistent with observations on equitable complete samples in the entire observed redshift range, when due account is taken of flux limits by an optimal statistical method. Under the theoretical assumption that space is a fixed sphere, as in the Einstein universe, this law implies the redshift-distance relation z = tan2(r/2R), where R is the radius of the spherical space. This relation coincides with the prediction of chronometric cosmology, which estimates R as 160 +/- 40 Mpc (1 parsec = 3.09 x 10(16) m) from the proper motion to redshift relation of superluminal sources. Tangential aspects, including statistical methodology, fundamental physical theory, bright cluster galaxy samples, and proposed luminosity evolution, are briefly considered.     

Duodenal ulcer and working-class mobility in an African population in South Africa

The number of Africans in Johannesburg presenting with duodenal ulcers has steadily increased over the past 50 years. The characteristics of 105 patients with duodenal ulcer who presented a Baragwanath Hospital were compared with those of matched and unmatched samples of patients without gastrointestinal conditions in the same hospital. Men with duodenal ulcers were found to be significantly better educated than their controls, most had been born in the town, and more of them were employed at higher, though not the highest, educational levels. These data were used to test Susser's proposition that duodenal ulcers are associated with "early urbanisation." Johannesburg blacks with duodenal ulcer did seem to fit the pattern, but the relation between stress and duodenal ulcer remains unclear.     

Escalating dose methamphetamine pretreatment alters the behavioral and neurochemical profiles associated with exposure to a high-dose methamphetamine binge.

The neurotoxic effects of methamphetamine (METH) have been characterized primarily from the study of high-dose binge regimens in rodents. However, this drug administration paradigm does not include a potentially important feature of stimulant abuse in humans, that is, the gradual escalation of stimulant doses that frequently occurs prior to high-dose exposure. We have argued that pretreatment with escalating doses (EDs) might significantly alter the neurotoxic profile produced by a single high-dose binge. In the present study, we tested this hypothesis by pretreating rats with saline or gradually increasing doses of METH (0.1-4.0 mg/kg over 14 days), prior to an acute METH binge (4 x 6 mg/kg at 2 h intervals). These animals, whose behavior was continuously monitored throughout drug treatment, were then killed 3 days later for determination of caudate-putamen dopamine (DA) content, levels of [(3)H]WIN 35,428 binding to the DA transporter, and levels of [(3)H]dihydrotetrabenazine ([(3)H]DTBZ) binding to the vesicular monoamine transporter. ED pretreatment markedly attenuated the stereotypy response, as well as the hyperthermia and indices of sympathetic activation associated with the acute binge. In addition, ED pretreatment prevented the decline in [(3)H]WIN 35,428 binding, and significantly diminished the decrease in DA levels, but did not affect the decrease in [(3)H]DTBZ binding associated with the acute binge. We suggest that further study of the effects produced by a regimen which includes a gradual escalation of doses prior to high-dose METH binge exposure could more accurately identify the neurochemical and behavioral changes relevant to those that occur as a consequence of high-dose METH abuse in humans.     

Classification of clear-cell sarcoma as a subtype of melanoma by genomic profiling.

PURPOSE: To develop a genome-based classification scheme for clear-cell sarcoma (CCS), also known as melanoma of soft parts (MSP), which would have implications for diagnosis and treatment. This tumor displays characteristic features of soft tissue sarcoma (STS), including deep soft tissue primary location and a characteristic translocation, t(12;22)(q13;q12), involving EWS and ATF1 genes. CCS/MSP also has typical melanoma features, including immunoreactivity for S100 and HMB45, pigmentation, MITF-M expression, and a propensity for regional lymph node metastases. MATERIALS AND METHODS: RNA samples from 21 cell lines and 60 pathologically confirmed cases of STS, melanoma, and CCS/MSP were examined using the U95A GeneChip (Affymetrix, Santa Clara, CA). Hierarchical cluster analysis, principal component analysis, and support vector machine (SVM) analysis exploited genomic correlations within the data to classify CCS/MSP. RESULTS: Unsupervised analyses demonstrated a clear distinction between STS and melanoma and, furthermore, showed that CCS/MSP cluster with the melanomas as a distinct group. A supervised SVM learning approach further validated this finding and provided a user-independent approach to diagnosis. Genes of interest that discriminate CCS/MSP included those encoding melanocyte differentiation antigens, MITF, SOX10, ERBB3, and FGFR1. CONCLUSION: Gene expression profiles support the classification of CCS/MSP as a distinct genomic subtype of melanoma. Analysis of these gene profiles using the SVM may be an important diagnostic tool. Genomic analysis identified potential targets for the development of therapeutic strategies in the treatment of this disease.