Influence of comorbidities on patients reported outcomes in degenerative lumbar spinal stenosis

INTRODUCTION

In degenerative lumbar spinal stenosis (DLSS) variability of symptoms according to the severity of stenosis is not well understood. Therefore, another factor that impacts functional outcomes of DLSS patients has been evoked: patient's comorbidities. The aim of this study was to investigate influence of comorbidities on clinical symptoms and functional outcomes in DLSS patients.

METHODS

In this prospective study, patients treated for DLSS were included during 12 consecutive months. Both clinical and radiographic exams were required to confirm DLSS diagnosis. Epidemiologic, clinical and radiographic data were collected. Two questionnaires were used to assess functional outcomes: a specific score dedicated to lumbar stenosis consequences assessment (self-administered Beaujon questionnaire, SABQ) and a non-specific score (Short Form 36, SF-36). Four comorbidity scores were calculated: Cumulative Illness Rating Scale, Charlson index, Functional Comorbidity Index and Index of Co-Existent Diseases Correlations between functional and comorbidity scores were calculated.

RESULTS

250 patients were included (65.6±12 years). The four comorbidities scores were significantly correlated to total SABQ, as well as lumbar and radicular ischemia components. Best correlations were observed for cumulative illness rating scale and SABQ. Two factors were observed that significantly influenced the relationship between SABQ and cumulative illness rating scale: herniated disc and SF-36 general health perception.

DISCUSSION

This study highlighted that preoperative function is influenced by comorbidities in DLSS patients. Relationships existed between comorbidities and symptoms related to low back pain and neurogenic claudication, contrary to radicular pain. Therefore, comorbidities might impact the variability of patients' outcomes. This finding should be part of the patient's preoperative information. Moreover, role of comorbidities on postoperative outcomes need to be investigated.

Techno-economic analysis of the deacetylation and disk refining process: characterizing the effect of refining energy and enzyme usage on minimum sugar selling price and minimum ethanol selling price

BACKGROUND

A novel, highly efficient deacetylation and disk refining (DDR) process to liberate fermentable sugars from biomass was recently developed at the National Renewable Energy Laboratory (NREL). The DDR process consists of a mild, dilute alkaline deacetylation step followed by low-energy-consumption disk refining. The DDR corn stover substrates achieved high process sugar conversion yields, at low to modest enzyme loadings, and also produced high sugar concentration syrups at high initial insoluble solid loadings. The sugar syrups derived from corn stover are highly fermentable due to low concentrations of fermentation inhibitors. The objective of this work is to evaluate the economic feasibility of the DDR process through a techno-economic analysis (TEA).

RESULTS

A large array of experiments designed using a response surface methodology was carried out to investigate the two major cost-driven operational parameters of the novel DDR process: refining energy and enzyme loadings. The boundary conditions for refining energy (128-468 kWh/ODMT), cellulase (Novozyme's CTec3) loading (11.6-28.4 mg total protein/g of cellulose), and hemicellulase (Novozyme's HTec3) loading (0-5 mg total protein/g of cellulose) were chosen to cover the most commercially practical operating conditions. The sugar and ethanol yields were modeled with good adequacy, showing a positive linear correlation between those yields and refining energy and enzyme loadings. The ethanol yields ranged from 77 to 89 gallons/ODMT of corn stover. The minimum sugar selling price (MSSP) ranged from $0.191 to $0.212 per lb of 50 % concentrated monomeric sugars, while the minimum ethanol selling price (MESP) ranged from $2.24 to $2.54 per gallon of ethanol.

CONCLUSIONS

The DDR process concept is evaluated for economic feasibility through TEA. The MSSP and MESP of the DDR process falls within a range similar to that found with the deacetylation/dilute acid pretreatment process modeled in NREL's 2011 design report. The DDR process is a much simpler process that requires less capital and maintenance costs when compared to conventional chemical pretreatments with pressure vessels. As a result, we feel the DDR process should be considered as an option for future biorefineries with great potential to be more cost-effective.

Removal of infected cemented hinge knee prostheses using extended femoral and tibial osteotomies: six cases

Extended femoral and tibial osteotomies were performed to remove infected cemented hinged knee prostheses in five patients (six knees) with a mean age of 72 years (44-85) and a history of multiple knee surgeries. A tibial osteotomy was used to mobilise the distal quadriceps insertion and to release the tibial extension. The femoral component was extracted by downward traction and its cement mantle was cleared through an anterior osteotomy (n=4) or via the distal approach (n=2). The bone flaps were re-approximated by wire cerclage over articulating acrylic spacers. Mean time to re-implantation of a new knee prosthesis was 11 months (6-24). Revision prostheses with cement fixation restricted to the epiphyseal-metaphyseal region were used. Infection recurred in two cases at 16 and 4 months after the prosthetic re-implantation, and was managed by joint fusion for one and irrigation/lavage for the other, respectively. At last follow-up after a mean of 53 months, the mean Parker score was 4 ± 2, the mean IKS knee score was 66 ± 25 (28-93), and the mean IKS function score was 7 ± 16 (0-40). This technique facilitates the removal of infected cemented components of hinge prostheses and of the cement mantle, most notably in the absence of loosening, without compromising re-implantation of a new knee prosthesis.

Three-dimensional stereoradiographic modeling of rib cage before and after spinal growing rod procedures in early-onset scoliosis

BACKGROUND

Early-onset scoliosis frequently leads to major thoracic deformity and pulmonary restrictive disease. Growing rods surgical techniques were developed to achieve a satisfactory correction of the spinal curves during growth. The effect on the rib cage deformity has not yet been documented. The purpose of this study was to analyze the changes of the thoracic geometry after implantation of a growing rod, and to evaluate a stereoradiographic reconstruction method among young scoliotic patients.

METHODS

Four patients were enrolled in the study, and four additional patients in the reproducibility study. Three-dimensional spine and rib cage models were generated after low-dose stereoradiographic imaging (EOS). Three-dimensional parameters were computed before and after surgery. Intra and inter-observer reproducibility was calculated, and the accuracy was assessed in comparison to volumetric CT-scan.

FINDINGS

The average Cobb angle was reduced from 50.8 degrees to 26 degrees . The surgery resulted in a complex 3D effect on the rib cage, combining frontal, lateral, and axial rotation. This effect was dependent of the side (concave or convex), and the position relative to the apical vertebra. Mean errors in comparison to CT-scan were 3.5mm.

INTERPRETATION

The results on the spinal deformity are comparable to other series. The effect on the rib cage is of a smaller magnitude than in the case of a spinal arthrodesis. A longer follow-up is necessary to confirm the positive effect on the rib cage deformity. Further research should be performed to improve the reproducibility of 3D parameters.

Surgical management of pelvic primary bone tumors involving the sacroiliac joint

INTRODUCTION

Pelvic primary malignant bone tumours, especially when involving the sacroiliac joint are difficult to treat. Abdominoperineal amputations are today used, only in life-threatening situations.

HYPOTHESIS

A precisely planed surgical technique can save the affected extremity without compromising the resection quality and subsequent patient survival.

OBJECTIVE

To assess the procedures used for resection and reconstruction of bone tumours invading the sacroiliac joint as well as their effects on cancer outcome and functional results.

MATERIALS AND METHODS

This is a continuous and retrospective analysis of 24 patients treated between 1986 and 2003. Six tumours affected the sacral body and 18 tumours involved the wing of the ilium. The joint articular surface was invaded in only six cases. Seventeen patients received neoadjuvant chemotherapy. The procedure was performed through an enlarged iliac crest incision, giving access to two sections of the pelvic ring. Six cases required neurological sacrifice. Initial tumour grading was based on the Enneking classification, and the functional results, on the Musculoskeletal Tumour Society (MSTS) scoring system.

RESULTS

The average operation lasted 5.27 hours. Reconstruction was performed with bone autograft and instrumentation. Resection was large with adequate margins 11 times, marginal 12 times, and contaminated once. Average follow-up was 4.77 years. The 5-year survival rate was 50%. Twelve patients either died from their disease or were in the metastatic stage at final follow-up. Survival was linked to the quality of resection and initial tumour staging. Hemisacrectomy did not affect patient survival. Local recurrences had a poor prognosis with eight cases of secondary metastases out of 11. Bone healing occurred in 13 patients, 10 of whom survived. Of the 12 patients who survived and were in complete remission at final follow-up, the average MSTS score was 61%. The score was at 38.6% in cases involving neurological sacrifice, and at 77.1% for the rest of the group. It was at 64% in healed cases and 13% in nonunion cases.

DISCUSSION

The survival of patients presenting with a sacroiliac joint tumour is substantially related to both tumour histology and resection quality. Local recurrences carry a poor prognosis with a high rate of secondary metastatic dissemination. In situations where disease control can be achieved, the proposed method of reconstruction allows, satisfactory bone healing and fair functional recovery, provided no major neurological sacrifice has taken place.

LEVEL OF EVIDENCE

level IV: Retrospective Therapeutic Study.

Closed reduction with traction for developmental dysplasia of the hip in children aged between one and five years

The treatment of developmental dysplasia of the hip diagnosed after the first year of life remains controversial. A series of 36 children (47 hips), aged between one and 4.9 years underwent gradual closed reduction using the Petit-Morel method. A pelvic osteotomy was required in 43 hips (91.5%). The patients whose hips did not require pelvic osteotomy were among the youngest. The mean age at final follow-up was 16.1 years (11.3 to 32). The mean follow-up was 14.3 years (10 to 30). At the latest follow-up, 44 hips (93.6%) were graded as excellent or good according to the Severin classification. Closed reduction failed in only two hips (4.3%) which then required open reduction. Mild avascular necrosis was observed in one (2.1%). The accuracy of the reduction and associated low complication rate justify the use of the Petit-Morel technique as the treatment of choice for developmental dysplasia of the hip in patients aged between one and five years.

Introducing printed postpartum orders for measles-mumps-rubella vaccination: a qualitative study

OBJECTIVE

After introducing printed postpartum orders at our centre, we observed a large increase in measles-mumps-rubella (MMR) vaccination of susceptible women. The objective of this study was to ascertain factors responsible for the success of our approach and to identify potential obstacles so as to facilitate the implementation of similar policies at other hospitals.

METHODS

For this qualitative study, taped semi-structured interviews were carried out with physicians, nurses, and a ward clerk regarding their views on postpartum MMR vaccination and on various aspects of implementing a printed postpartum order sheet that included MMR vaccination of susceptible women. Interviews were transcribed and the responses classified by theme. Thematic analysis was used to identify strengths and weaknesses of this approach.

RESULTS

Following implementation of printed postpartum orders that included MMR vaccination of susceptible women, the proportion of eligible women vaccinated increased from 12.1 to 81.7% (risk ratio 6.8, 95% confidence interval [CI] 3.3, 13.7). While the physician and nursing staff broadly supported this initiative, we identified the need for changes in obstetrical care and documentation: most importantly, a comprehensive protocol with supporting information and guidelines should be provided for postpartum nurses; and a system must be in place to ensure that the completed antenatal record, including screening test results, be available in the expected hospital of delivery by the late second trimester.

CONCLUSION

Previously undocumented claims that standing orders for postpartum MMR vaccination will increase the rate of vaccination of susceptible women have now been substantiated at one centre. Nevertheless, careful infrastructure and systems changes are required to ensure implementation of such orders.

First Report of Pepino mosaic virus in Canada and the United States

During the winter of 2000, tomatoes (Lycopersicon esculentum) with a bright yellow leaf mosaic were observed in a commercial greenhouse in southern Ontario, Canada. Examination of leaf extracts, using leaf dips and immunosorbent absorption electron microscopy (ISEM), showed flexuous rods consistent with the potexvirus group. Polyclonal antibodies raised against the original Peruvian Pepino mosaic virus (PepMV) isolate (1) and commercial antibodies obtained from Deutsche Sammlung von Mikro-organismen und Zellkulturen (DSMZ), GmbH, Braunsweig, Germany, and Plant Research International (PRI), Wageningen, the Netherlands, were used in ISEM. Leaves tested positive in double-antibody sandwich-enzyme-linked immunosorbent assay (ELISA) with antibodies from DSMZ and PRI. A triple-antibody sandwich-ELISA obtained from Adgen Ltd. (Nellies Gate, UK) gave similar results. Potato virus X did not react with PepMV antiserum in ELISA. Positive PepMV ELISA controls were a U.K. and a Dutch isolate supplied by R. Mumford and R. A. A. van Vlugt, respectively, and DSMZ. Using primers generated from a sequence of the RNA polymerase region of a U.K. PepMV isolate (R. Mumford, unpublished data), a reverse transcription-polymerase chain reaction test showed the expected 312-bp amplicon for the Canadian, Dutch, and U.K. isolates. The primer sequences used were forward 5' CTA TTA CAA CTC CGG AAG CCA 3' and reverse 5' TGG TCT GGC CAG GCT TTG AC 3'. The three isolates were maintained in tomato cv. Bush Beefsteak. When mechanically inoculated on L. esculentum cv. Rapsodie, the Canadian isolate caused a bright yellow mosaic in 1 to 2 weeks, while the two European isolates caused a faint yellow mosaic and mild puckering of the leaves. When mechanically inoculated on 17 indicator plants, the Canadian isolate had a host range similar to the U.K. isolate. The most striking difference in symptoms occurred in L. pimpinellifolium, in which the Canadian isolate caused a yellow mosaic, the Dutch isolate caused no symptoms, and the U.K. isolate caused a marked puckering of the leaves, suggesting virus strain differences among the isolates. Tomato fruits originating from the United States were collected during border inspections by the Canadian Food Inspection Agency and tested for PepMV by ELISA with antisera from DSMZ. PepMV was not detected in 7 samples from California, but was detected in 6 of 12 samples from Colorado, 6 of 7 samples from Arizona, and 1 of 5 samples from Texas. PepMV was originally isolated from pepino (Solanum muricatum) in Peru in 1980 (1) and subsequently from tomato in the Netherlands in 1999 (2). To our knowledge, this is the first report of PepMV in North America. References: (1) R. Jones et al. Ann. Appl. Biol. 94:61, 1980. (2) R. A. A. van Vlugt et al. Plant Dis. 84:103, 2000.

Characterization of hch, the Podospora anserina homolog of the het-c heterokaryon incompatibility gene of Neurospora crassa

The het-c locus controls heterokaryon formation in Neurospora crassa. It is subject to balancing selection operating to maintain polymorphism at that locus in natural populations. We have isolated hch, the het-c homolog from the related species Podospora anserina (hch for het-c homolog), in order to determine if this gene also functions as a het gene in that species. The het-c and hch sequences are highly similar but differ in the region defining allele specificity in N. crassa het-c. Analysis of hch variability in 11 natural P. anserina isolates with different het genotypes revealed no polymorphism. This suggested that hch does not function as a het gene. However, heterologous expression of the N. crassa het-cPA allele in P. anserina triggers a growth defect reminiscent of the het-c incompatibility reaction.

Sensitivity of human type II topoisomerases to DNA damage: stimulation of enzyme-mediated DNA cleavage by abasic, oxidized and alkylated lesions

Type II topoisomerases are essential enzymes that are also the primary cellular targets for a number of important anticancer drugs. These drugs act by increasing levels of topoisomerase II-mediated DNA cleavage. Recent studies indicate that endogenous forms of DNA damage, such as abasic sites and base mismatches, also stimulate the DNA scission activity of the enzyme. To extend our understanding of how type II topoisomerases react to DNA damage, the effects of abasic sites, and oxidized and alkylated bases on DNA cleavage mediated by human topo-isomerase IIalpha and beta were determined. Based on experiments that incorporated random abasic sites into plasmid DNA, human type II enzymes can locate lesions even within a background of several thousand undamaged base pairs. As determined by experiments that utilized site-specific forms of DNA lesions, oxidized or monoalkylated purines that allow base pairing and induce little distortion in the double helix have modest effects on topoisomerase II-mediated DNA cleavage. In contrast, 1,N(6)-ethenoadenine, a bulky lesion that disrupts base pairing, enhanced DNA cleavage approximately 10-fold. 1,N(6)-Ethenoadenine is the first lesion found to rival the stimulatory effects of apurinic sites on the DNA scission activity of eukaryotic type II topoisomerases.

[The evolution of ethical standards in the practice of psychology: a reflection on the APA Code of Ethics]

After briefly describing the need for ethics in the development of professional regulation and analyzing the historical emergence of codes of ethics, the goal of this paper is to scrutinize the process by which the American Psychological Association developed its own Code of Ethics and proceeded to revise it periodically. Different lessons can be derived from these efforts and from the criticisms that were formulated. The need for international standards in professional and research ethics is then considered, and the results of a recent study on this subject are presented. Five major conclusions can be derived from the preceding analysis: (1) Codes of ethics can help professional recognition by stressing the importance given to the protection of the public, (2) the development of a code of ethics is usually related to the advancement of professional practice, (3) ethical standards should be in tune with the cultural values and the belief system of a given community, (4) a well-balanced code should incorporate both general aspirational principles and enforceable standards, and (5) the method used to define principles and standards should be empirically based.

A mutant yeast topoisomerase II (top2G437S) with differential sensitivity to anticancer drugs in the presence and absence of ATP

To further characterize the mechanistic basis for cellular resistance/hypersensitivity to anticancer drugs, a yeast genetic system was used to select a mutant type II topoisomerase that conferred cellular resistance to CP-115,953, amsacrine, etoposide, and ellipticine. The mutant enzyme contained a single point mutation that converted Gly437 --> Ser (top2G437S). Purified top2G437S displayed wild-type enzymatic activity in the absence of drugs but exhibited two properties that were not predicted by the cellular resistance phenotype. First, in the absence of ATP, it was hypersensitive to all of the drugs examined and hypersensitivity correlated with increased drug affinity. Second, in the presence of ATP, top2G437S lost its hypersensitivity and displayed wild-type drug sensitivity. Since the resistance of yeast harboring top2G437S could not be explained by alterations in enzyme-drug interactions, physiological levels of topoisomerase II were determined. The Gly437 --> Ser mutation reduced the stability of topoisomerase II and decreased the cellular concentration of the enzyme. These findings suggest that the physiological drug resistance phenotype conferred by top2G437S results primarily from its decreased stability. This study highlights the need to analyze both the biochemistry and the physiology of topoisomerase II mutants with altered drug sensitivity in order to define the mechanistic bridge that links enzyme function to cellular phenotype.

Oxidative metabolism of 1-(2-chloroethyl)-3-alkyl-3- (methylcarbamoyl)triazenes: formation of chloroacetaldehyde and relevance to biological activity

(Methylcarbamoyl)triazenes have been shown to be effective cancer chemotherapeutic agents in a number of biological systems. Because of their chemical stability, it is likely that their activity in vivo is the result of a metabolic activation process. Previous studies have shown that 1-(2-chloroethyl)-3-methyl-3-(methylcarbamoyl)triazene (CMM) and 1-(2-chloroethyl)-3-benzyl-3-(methylcarbamoyl)triazene (CBzM) are metabolized by rat liver microsomes in the presence of NADPH to yield the ((hydroxymethyl)carbamoyl)triazene analogs of the parent compounds. The present studies show that both compounds are also oxidized at the chloroethyl substituent to yield chloroacetaldehyde and a substituted urea. In the case of CBzM metabolism, 47% of the metabolized parent compound was recovered as benzylmethylurea, 8% was recovered as benzylurea, and 26% was recovered as the ((hydroxymethyl)carbamoyl)-triazene and carbamoyltriazene metabolites. These results suggest that the chloroethyl group is the favored initial site of metabolism. In reaction mixtures containing initial concentrations of 300 microM CBzM, 78 microM chloroacetaldehyde was produced, as compared to 58 microM chloroacetaldehyde produced from the metabolism of 300 microM CMM. The formation of chloroacetaldehyde, a known mutagenic DNA alkylating agent, may explain the biological activity of these compounds.

Evaluation of hypnotically-suggested selective deafness by heart-rate conditioning and reaction time

This study was designed to evaluate the effects of suggested selective deafness on heart-rate conditioning and reaction time. 20 highly hypnotizable subjects were randomly assigned to four groups (hypnotic, post-hypnotic, motivational, and control). After the establishment of the heart-rate conditioned response, a suggestion of selective deafness for the CS was given, followed by 15 trials of extinction; subsequently, the suggestion was lifted and 15 additional trials were given. The results show that the suggestion did not influence the heart-rate conditioned response, nor did it influence reaction time. The discussion centers around subjective aspects and methodological factors; also, the data are interpreted in relation to the “hidden observer” model.

Effects of active and passive EMG biofeedback training on performance of motor and cognitive tasks

The goal of this study was to compare the effects of general relaxation (passive group) and neuromuscular tension control (active group), both using EMG biofeedback techniques, on the performance of memorization, simple reaction time, and rotary pursuit. 18 subjects were given five consecutive daily sessions of training or were placed under control conditions, after which their performance on these various tasks was evaluated. Results indicate that control of neuromuscular tension seemed to facilitate performance on all tasks over that of the control group. Except for simple reaction time, there was no difference between the "active" and "passive" groups. The results are interpreted in terms of factors in selection of subjects and experimental conditions.

Changes in heart rate levels during avoidance conditioning in the rabbit

During avoidance conditioning heart rate levels tend to increase or to decrease according to their initial values and these changes are not related to learning or performance of the task.

Effect of light on thermal reinforcement in behavioral thermoregulation

The purpose of this study was to demonstrate the effect (reinforcing or aversive) of the combination of light and heat for the presentation of thermal reinforcement in behavioral thermoregulation. The results obtained indicate that the light-heat reinforcement group requires significantly less reinforcers and bar-presses for reaching the learning criterion than the heat-reinforced group. However, the time for reaching criterion and the performance observed after learning has occurred are not significantly different. The results show that light is not an aversive factor in this condition and are explained in relation to the temporary and transitory effect of sensory reinforcement suggested by Tapp and Simpson (1960).