Systematic review and evidence gap mapping of biomarkers associated with neurological manifestations in patients with COVID-19

OBJECTIVE

This study aimed to synthesize the existing evidence on biomarkers related to coronavirus disease 2019 (COVID-19) patients who presented neurological events.

METHODS

A systematic review of observational studies (any design) following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and the Cochrane Collaboration recommendations was performed (PROSPERO: CRD42021266995). Searches were conducted in PubMed and Scopus (updated April 2023). The methodological quality of nonrandomized studies was assessed using the Newcastle‒Ottawa Scale (NOS). An evidence gap map was built considering the reported biomarkers and NOS results.

RESULTS

Nine specific markers of glial activation and neuronal injury were mapped from 35 studies published between 2020 and 2023. A total of 2,237 adult patients were evaluated in the included studies, especially during the acute phase of COVID-19. Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) biomarkers were the most frequently assessed (n = 27 studies, 77%, and n = 14 studies, 40%, respectively). Although these biomarkers were found to be correlated with disease severity and worse outcomes in the acute phase in several studies (p < 0.05), they were not necessarily associated with neurological events. Overall, 12 studies (34%) were judged as having low methodological quality, 9 (26%) had moderate quality, and 9 (26%) had high quality.

CONCLUSIONS

Different neurological biomarkers in neurosymptomatic COVID-19 patients were identified in observational studies. Although the evidence is still scarce and conflicting for some biomarkers, well-designed longitudinal studies should further explore the pathophysiological role of NfL, GFAP, and tau protein and their potential use for COVID-19 diagnosis and management.

Fibroblast growth factor in the treatment of burns: A systematic review

INTRODUCTION

A burn is a trauma that breaks the skin barrier, causing local and systemic responses. Treatment is complex, multiprofessional and expensive. In addition to surgical treatment, topical dressings can be used to keep the wound moist, reduce the risk of infection and stimulate healing. Clinical studies show that topical use of fibroblast growth factors may accelerate healing. An assessment of the quality of the available evidence and its strength of recommendation is necessary.

OBJECTIVE

This study aimed to evaluate the effectiveness and safety of topical use of fibroblast growth factor, compared to other topical treatments or placebo, in the healing of burns, to determine the strength of recommendation.

METHOD

Based on a defined search strategy, randomized and quasi-randomized clinical trials, available in electronic databases, were gathered. These compare the topical use of FGF versus other topical or non-treatment. The primary outcome was healing and as adverse effects: pain, infection and mortality. The systematic review protocol was registered on the PROSPERO platform (CRD42018089556), developed in accordance with the "Preferred Reporting Items for Systematic review and Meta-Analysis Protocols (PRISMA-P) 2015" and within the "SWiM guideline 2019". GRADEpro was used for the critical analysis of the methodology of the studies.

RESULTS

Four clinical trials were found, in which FGF reduced the healing time and improved the appearance of the scar. Two trials were determined to be of low strength, while two others have a moderate recommendation strength.

CONCLUSION

This review gathered available evidence, between low and moderate recommendation strength for the use of FGF as a topical dressing. Further rigorous trials are needed to improve the strength of recommendation for topical use of FGF for burns.

Body dysmorphic disorder and personality in breast augmentation: The big-five personality traits and BDD symptoms

BACKGROUND

Breast augmentation is one of the most performed cosmetic surgeries in the world. Personality traits predict the presence of psychological and social factors that may affect the patient satisfaction with a cosmetic surgical procedure and may be risk factors for body dysmorphic disorder. The aim of this study was to assess symptoms of body dysmorphic disorder in patients undergoing breast augmentation and identify their personality traits.

METHODS

Thirty-six women with hypoplasia of the breast (Sacchini index < 9 cm), a mean age of 28.1 years (SD = 6.2), body mass index ≤ 25 kg/m², and no history of breast surgery or breast-associated conditions were included in this prospective study.The Brazilian versions of the Structured Clinical Interview (SCID-I), Big Five Inventory (IGFP-5), and Body Dysmorphic Symptoms Scale (BDSS) were applied preoperatively and at 2 and 4 months after breast augmentation.

RESULTS

Personality traits were associated with symptoms of body dysmorphic disorder. A significant decrease (p< 0.001) in IGFP-5 scores on the Conscientiousness dimension, symptoms of body dysmorphic disorder (BDSS scores), and the number of patients with body dysmorphic disorder (SCID-I) were observed among different time points. In the study population, breast augmentation decreased the symptoms of body dysmorphic disorder, psychosocial impairment, and mean scores on Conscientiousness.

CONCLUSION

Personality traits varied in intensity and overlapped over time, and were associated with core symptoms of body dysmorphic disorder and the onset of body dissatisfaction.

Ketoprofen-loaded rose hip oil nanocapsules attenuate chronic inflammatory response in a pre-clinical trial in mice

This study aimed to develop nanocapsules containing ketoprofen using rose hip oil (Keto-NC) as oil core, and to evaluate their anti-inflammatory activity in acute and chronic ear edema models in mice. Physicochemical characterization, drug release, photostability and cytotoxicity assays were performed for the developed Keto-NC formulations and compared to ketoprofen-loaded nanocapsules using medium chain triglycerides as oil core (Keto-MCT-NC). Anti-inflammatory activity of orally delivered KP (Ketoprofen-free; 10 mg.kg^-1) or Keto-NC (2.5; 5; 10 mg.kg^-1) was assessed in mouse acute and chronic ear edema induced by croton oil (CO). Edema histological characteristics were determined by H&E stain, and redox parameters were analyzed in blood plasma and erythrocytes. Keto-MCT-NC and Keto-NC did not exhibit differences regarding physicochemical parameters, including size diameters, polydispersity index, pH, Ketoprofen content, and encapsulation efficiency. However, Keto-NC, which contains rose hip oil as lipid core, decreased drug photodegradation under UVC radiation when compared to Keto-MCT-NC. KP or Keto-NC were not cytotoxic to keratinocyte cultures and produced equal edema inhibition in the acute protocol. Conversely, in the chronic protocol, Keto-NC was more effective in reducing edema (~60-70% on 7-9th days of treatment) when compared to KP (~40% on 8-9th days of treatment). This result was confirmed by histological analysis, which indicated reduction of edema and inflammatory infiltrate. A sub-therapeutic dose of Keto-NC (5 mg.kg^-1) significantly reduced edema when compared to control. Finally, KP and Keto-NC exhibited similar effects on redox parameters, suggesting that the advantages associated with Ketoprofen nanoencapsulation did not involve oxidative stress pathways. The results showed that Keto-NC was more efficient than KP in reducing chronic inflammation. These data may be important for the development of strategies aiming treatment of chronic inflammatory diseases with fewer adverse effects.

Physical activity, functional ability, and quality of life after breast cancer surgery

This cross-sectional study aimed to assess the influence of different surgical treatment modalities on the level of physical activity, functional capacity, and quality of life of breast cancer survivors. One hundred eighty women aged 30-60 years old were selected and allocated to control group (CG, women without breast cancer, n = 45), breast-conserving surgery group (BCG, n = 45), mastectomy group (MG, n = 45), and breast reconstruction group (BRG, n = 45). Physical activity, functional capacity, and quality of life were assessed, respectively, using the following self-report questionnaires validated for use in Brazil: International Physical Activity Questionnaire (IPAQ), Stanford Health Assessment Questionnaire (HAQ-20), and Medical Outcomes Study 36-item Short-Form Health Survey (SF-36). The groups were homogeneous relative to sociodemographic variables. The scores for physical activity (IPAQ) did not differ between CG and BRG, whereas they were better for CG than for BCG and MG (p = 0.0270). The results for functional capacity (HAQ-20) were better for CG than for MG (p = 0.0450), with no difference between the remaining groups. Differences were found for the SF-36 domains "physical functioning" (p < 0.01), "physical role functioning" (p < 0.001), "emotional role functioning" (p = 0.0174), and "general health" (p = 0.0307). CG and BRG differed significantly relative to the domains "physical role functioning" and "emotional role functioning" only. We concluded that patients who underwent breast reconstruction exhibited higher levels of physical activity and quality of life than patients subjected to mastectomy alone or breast-conserving surgery.

Redistribution of Cs 137 introduced into montmorillonite in association with organic matter coming from biomass composting

The adsorption and later bioavailability of ¹³⁷Cs from the system humic acid (HA)/humic acid like compounds (HALC) and montmorillonite was investigated. The setup of the experiments should approach as much as possible natural conditions when ¹³⁷Cs is introduced into soil with HALC from decomposed biomass. The significant differences were found in the trials containing various HA/HALC and also pure montmorillonite. The ¹³⁷Cs was more available when it reached soil in association with HALC originated from compost than when it was adsorbed on stable humic acids. Moreover, the long term interaction of ¹³⁷Cs with HALC led to decrease of ¹³⁷Cs adsorbed on montmorillonite and increase of its bioavailable fraction. UV-Vis spectrometry and infrared spectroscopy showed the clear difference between HA, fresh HALC and old HALC which could partially explain the different results.

Evaluation of genome similarities using the non-decimated wavelet transform

The wavelets have become increasingly popular in the field of bioinformatics due to their capacity in multiresolution analysis and space-frequency localization; the latter particularity is acquired due to a moving window that runs through the analyzed space. As a feature, they have a better ability to capture hidden components of biological data and an efficient link between biological systems and the mathematical objects used to describe them. The decomposition of signals/sequences at different levels of resolution allows obtaining distinct characteristics in each level. The energy (variance) obtained at each level provides a new set of information that can be used to search similarities between sequences. We show that the behavior of GC-content sequence can be succinctly described regarding the non-decimated wavelet transform, and we indicate how this characterization can be used to improve clustering of the similar strains of the genome of the Mycobacterium tuberculosis, having a very efficient level of detail. The clustering analysis using the energy obtained at each level of the analyzed sequences was essential to verify the dissimilarity of the sequences.

Impact of surgical wound dehiscence on health-related quality of life and mental health

OBJECTIVE

To assess the impact of surgical wound dehiscence on health-related quality of life and mental health. Dehiscence of surgical wounds is a serious postoperative complication associated with high morbidity and mortality.

METHOD

Sixty-one adult patients, who had undergone neurological, general, colorectal, orthopaedic, gynaecological, plastic, cardiovascular, urological or neurological surgery in a university hospital in Brazil, were assessed between 30 and 180 days after surgery. Twenty participants who achieved complete wound healing were allocated to the control group and 41 participants who developed surgical wound dehiscence were allocated to the dehiscence group. Patients unable to complete the questionnaires because of cognitive impairment and those who declined to participate or died were excluded from the study. Data were collected using a questionnaire assessing sociodemographic and clinical characteristics of participants; the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36); and the Beck Depression Inventory (BDI).

RESULTS

Surgical wound dehiscences were 0.5-30 cm in length, 0.5-7 cm in depth, and located in the arms, legs or trunk. There were significant between-group differences in mean scores on the physical functioning (p<0.01), role physical (p<0.01), social functioning (p=0.01), and bodily pain (p=0.01) dimensions of the SF-36. Participants with wound dehiscence reported significantly higher BDI scores (more depressive symptoms) than controls (p=0.01).

CONCLUSION

Surgical wound dehiscence had a negative impact on the physical functioning, role physical, social functioning, and bodily pain dimensions of health-related quality of life and on mental health.

DECLARATION OF INTEREST

No conflict of interest to declare.

Toxicity of the amphetamine metabolites 4-hydroxyamphetamine and 4-hydroxynorephedrine in human dopaminergic differentiated SH-SY5Y cells

Amphetamine (AMPH) is a psychostimulant used worldwide by millions of patients in the clinical treatment of attention deficit hyperactivity disorder, narcolepsy or even obesity, and is also a drug of abuse. 4-Hydroxynorephedrine (4-OHNE) and 4-hydroxyamphetamine (4-OHAMPH) are two major metabolites known to persist in the brain longer than AMPH. The contribution of AMPH metabolites for its neurotoxicity is undetermined. We evaluated the toxicity of AMPH and its metabolites 4-OHNE and 4-OHAMPH, obtained by chemical synthesis, in human dopaminergic differentiated SH-SY5Y neurons. Cells were exposed to AMPH (concentration range 0-5mM) or 4-OHAMPH or 4-OHNE (concentration range 0-10mM) for 24 or 48h, and the viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase (LDH) leakage assays. Results showed that for both AMPH and the metabolites a concentration-dependent toxicity was observed. The toxic concentration 50% (TC₅₀) for AMPH and 4-OHNE following 24h exposure was circa 3.5mM and 8mM, respectively. For 4-OHAMPH the TC₅₀ was not reached in the tested concentration range. N-acetyl cysteine, cycloheximide, l-carnitine, and methylphenidate were able to reduce cell death induced by AMPH TC₅₀. Acridine orange/ethidium bromide staining showed evident signs of late apoptotic cells and necrotic cells following 24h exposure to AMPH 3.50mM. The 4-OHAMPH metabolite at 8.00mM originated few late apoptotic cells, whereas 4-OHNE at 8.00mM resulted in late apoptotic cells and necrotic cells, in a scenario similar to AMPH. In conclusion, the AMPH metabolite 4-OHNE is more toxic than 4-OHAMPH, nonetheless both are less toxic than the parent compound in vitro. The most toxic metabolite 4-OHNE has longer permanence in the brain, rendering likely its contribution for AMPH neurotoxicity.

Neutrophil Respiratory Burst Activity and Pro- and Anti-inflammatory Cytokines in AAA Surgery: Conventional versus Endoluminal Treatment

Purpose:

To examine the inflammatory impact of endovascular and conventional surgery of abdominal aortic aneurysm (AAA) as assessed by the activation of neutrophils and serum levels of pro- and anti-inflammatory cytokines.

Methods:

Twenty-four patients undergoing AAA exclusion were treated with either endovascular (n = 14) or conventional (n=10) techniques. Clinical and hematological data, respiratory burst of neutrophils, and the expression of adhesion and activation molecules (CD18, CD11b, CD69, and HLA-DR) were analyzed by flow cytometry. The enzyme-linked immunosorbent assay technique was used to measure proinflammatory cytokine interleukin (IL)–8 and anti-inflammatory cytokines IL-1 receptor antagonist (IL-1RA) and transforming growth factor β1 (TGF-β1).

Results:

All patients, most of whom had normal cytokine values before surgery, were successfully treated. No significant changes were found in surface antigens. Basal respiratory burst was quite heterogeneous; in all cases respiratory burst activity decreased after surgery and remained low throughout the observation period. Despite marked interpatient differences, IL-1RA and IL-8 increased after surgery, whereas TGF-β1 decreased, although the variation achieved statistical significance only in the conventional group. Elevated IL-1RA returned to normal within 48 hours in the endoluminal group, whereas the level remained high in the conventional group in the last sample.

Conclusions:

Despite heterogeneity before surgery, the respiratory burst decreased for most of the patients regardless of the approach, and both techniques increased IL-1RA. Although both procedures seemed to decrease TGF-β1, the difference was significant only with the conventional approach. IL-1RA levels fell toward basal values quicker in the endograft patients, suggesting that the endoluminal approach was less aggressive.

Effect of delayed scanning on imaging and on the diagnostic accuracy of vertical root fractures in two photostimulable phosphor plates digital systems

AIM

To evaluate the influence of delayed scanning on images obtained with two PSPs digital systems and on the diagnostic accuracy of vertical root fracture (VRF) by means of objective and subjective analyses.

METHODOLOGY

Forty single-rooted human teeth were divided into two groups, one without VRFs and another with VRFs induced by a universal testing machine. Two digital systems (VistaScan(®) and Express(®) ) were used to radiograph all teeth, and the resulting plates were scanned at four time-points: T0-immediately, T1-30 min, T2-2 h and T3-4 h after exposure. An aluminium (Al) wedge was used to evaluate the change in mean grey values as each scan was delayed. Three observers screened all images for VRFs, and one-fourth of the sample was revaluated after thirty days. Areas under the receiver operating characteristic (ROC) curve, sensitivity, specificity and accuracy values were compared by anova.

RESULTS

Intra- and interobserver agreement ranged from moderate to substantial and fair to moderate, respectively. There was no significant difference amongst scan delays with regard to sensitivity, specificity and accuracy; however, there were significant differences in the area under the ROC curve, with the 4-h delayed scan being associated with lower values compared to the others (P = 0.019). As for objective analysis, there was a significant difference amongst all different scanning time-points for the two systems (P = 0.001), except between the 30-min and 2-h delayed scans in the VistaScan(®) system.

CONCLUSION

Whilst delayed scanning caused changes to the density of images acquired with the systems studied, it did not seem to interfere with VRF diagnosis except when scanning was delayed for 4 h, which should therefore be avoided.

Influence of CBCT enhancement filters on diagnosis of vertical root fractures: a simulation study in endodontically treated teeth with and without intracanal posts

OBJECTIVES

To evaluate the influence of CBCT enhancement filters on the diagnosis of vertical root fractures (VRFs) in teeth with and without metal posts.

METHODS

The crowns of 40 uniradicular human teeth were removed and all roots were prepared. 20 teeth were randomly selected, and VRFs were induced using a universal testing machine. The i-CAT (Imaging Sciences International, Hatfield, PA) CBCT was used to scan teeth with and without intracanal metal posts using the following parameters: 0.2 voxel size, 8 × 8-cm scan size and acquisition time of 26.9 s. Images were evaluated by three observers with and without the use of the following filters: S9, smooth, smooth 3 × 3, sharpen, sharpen-mild and sharpen 3 × 3.

RESULTS

Intra- and interobserver agreement ranged from poor to moderate. Images with and without CBCT filters did not show significant differences regarding the area under the receiver operating characteristic curve, as well as sensitivity (p > 0.05). As for accuracy, the sharpen-mild filter was superior to the sharpen (p = 0.03), but these filters did not differ from all others. For specificity, S9, smooth and original images were superior to sharpen (p < 0.01). Results for teeth without posts differed from those for teeth with metal posts in all cases (p < 0.05).

CONCLUSIONS

The use of enhancement filters in CBCT images has no influence on the diagnosis of VRFs in teeth with metal posts, and their use is not justified.

Effectiveness of CT for the detection of glenoid bone graft resorption following reverse shoulder arthroplasty

INTRODUCTION

Glenoid bone grafting is often used in cases of reverse shoulder arthroplasty (RSA) with glenoid deficiency. Additionally, bony increased-offset RSA (BIO-RSA) uses a cylindrical bonegraft harvested from the humeral head and is positioned beneath the glenoid baseplate to increase lateralization. Postoperative computed tomography (CT) has been used to detect glenoid bonegraft resorption, which is typically identified by a gap between the bonegraft and baseplate; however, CT images are often degraded by implant metal artifact. The purpose of this CT imaging study was to determine if a simulated bonegraft resorption gap is detectable following RSA with glenoid bone grafting.

HYPOTHESIS

CT is unable to detect bone graft resorption following reverse shoulder arthroplasty conducted with bone grafting beneath the glenoid baseplate.

MATERIALS AND METHODS

RSA with glenoid bone grafting was performed on four cadaver shoulders. Glenoid bonegraft resorption gaps were simulated by fixing the implant at six different gap widths (0, 1, 2, 4, 6 and 8mm). Clinical CT scans were acquired for each gap resulting in 6 scans per specimen. Two experienced observers (blinded) analyzed DICOM images in the axial and coronal directions, and measured gap widths using Mimics(®) software. Each observer had access to approximately 200 images per condition per specimen.

RESULTS

The sensitivity of CT imaging to positively identify bonegraft resorption was 38%, with an accuracy of 46%. Inter-observer agreement was 92%. Observers tended to visualize no-gap for most conditions. Resorption gap width measurements were consistently underestimated.

DISCUSSION

Metal artifact prevented identification of simulated bonegraft resorption gaps and observers most often determined that there was bonegraft-to-implant "healing" on CT, when in fact a gap was clinically present. This study illustrates the need for more effective imaging techniques to determine if bonegraft resorption has occurred following RSA.

Radial head implant diameter: A biomechanical assessment of the forgotten dimension

BACKGROUND

The effect of radial head implant length has been a subject of controversy, with the impact on clinical outcomes and forearm biomechanics being extensively studied. However, the impact of radial head diameter on forearm load transfer has not been examined. This study examined the influence of radial head implant diameter on forearm load transfer as measured by interosseous membrane tension and radiocapitellar joint contact characteristics.

METHODS

An upper extremity simulator was utilized to study five cadaveric specimens with three different radial head implant diameters (-2mm, anatomically sized, +2mm). A load sensing device was woven into the fibers of the central band of the interosseous membrane to quantify its tension. An inter-positional pressure measurement sensor was used to quantify radiocapitellar joint contact force and area. Axial loads of 160N were applied to the forearm during forearm rotation with the elbow at 90° of flexion.

FINDINGS

Changes to the radial head diameter did not change radiocapitellar contact force or area (P=0.4 and P=0.5 respectively). There was a linear relationship between radial head diameter and interosseous membrane tension; increasing radial head diameter increases the interosseous membrane tension (P=0.01).

INTERPRETATION

Although radial head diameter was not found to alter radiocapitellar contact area or force, the interosseous membrane tension was impacted. After radial head arthroplasty, an increase in radial head implant diameter increases the interosseous membrane tension, with a potential for increased pain and stiffness. There is also a potential for increased proximal radioulnar joint contact pressures; resulting in stem loosening or radio-ulnar pain.

Impact of compression therapy using Unna's boot on the self-esteem of patients with venous leg ulcers

OBJECTIVE

To assess self-esteem in patients with venous leg ulcers treated with Unna's boot. •

METHOD

A descriptive, analytic, clinical study was conducted from June 2010 to May 2011 in an outpatient wound care clinic in São Paulo, Brazil. Patients of both sexes, aged ≥18 years, who had had a venous leg ulcer for more than one year and a Doppler ankle brachial index ranging from 0.8-1.0 were consecutively selected for inclusion. Patients were treated with wound dressings and Unna's boot. Self-esteem was assessed using the Brazilian version of the Rosenberg Self-Esteem Scale (RSE) at inclusion (baseline) and after 4, 8, and 12 months of compression therapy using Unna's boot. The scale is reverse-scored; thus lower scores indicate higher levels of self-esteem. •

RESULTS

The patients showed a slight but significant improvement in self-esteem after 4 months of treatment (mean RSE score=17.12) compared with baseline (mean RSE score=24.90). However, a marked and significant improvement in self-esteem was observed after 8 months (mean RSE score=7.40) and 12 months (mean RSE score=2.10) of compression therapy using Unna's boot. •

CONCLUSION

Patients with venous leg ulcers treated with Unna's boot for 12 months showed a significant improvement in self-esteem •

DECLARATION OF INTEREST

All authors declare that no competing financial interests exist. There was no external funding for this study.

Quality of life and self-esteem in patients with paraplegia and pressure ulcers: a controlled cross-sectional study

OBJECTIVE

To evaluate health-related quality of life (HRQoL) and self-esteem in patients with traumatic spinal cord injury (SCI) and pressure ulcers.

METHOD

This study was a controlled cross-sectional study. HRQoL was assessed using the generic Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) questionnaire and the Rosenberg Self-Esteem/UNIFESP-EPM Scale. A total of 120 patients with traumatic SCI were included in the sample, of which 60 had pressure ulcers and were assigned to the study group, and 60 had no pressure ulcers and were assigned to the control group. Statistical analysis was performed using the chi-square test, Fisher's exact test, and Student's t-test.

RESULTS

Of the 60 patients in the study group, 83.3% were men and the mean age was 38.17 years (SD = 9.08 years). When compared with controls, patients in the study group reported significantly lower scores (worse health status) on all SF-36 subscales (p less than or equal to 0.0013) except for general health (p=0.109). The RSE/UNIFESP-EMP scale total score indicated that patients with pressure ulcers had significantly lower self-esteem than controls (p<0.001).

CONCLUSION

Pressure ulcers had an adverse impact on the HRQoL and self-esteem of patients with SCI.

DECLARATION OF INTEREST

There were no external sources of funding for this study. The authors have no conflicts of interest to declare.

Stress-induced changes in human decision-making are reversible

Appropriate decision-making relies on the ability to shift between different behavioral strategies according to the context in which decisions are made. A cohort of subjects exposed to prolonged stress, and respective gender- and age-matched controls, performed an instrumental behavioral task to assess their decision-making strategies. The stressed cohort was reevaluated after a 6-week stress-free period. The behavioral analysis was complemented by a functional magnetic resonance imaging (fMRI) study to detect the patterns of activation in corticostriatal networks ruling goal-directed and habitual actions. Using structural MRI, the volumes of the main cortical and subcortical regions implicated in instrumental behavior were determined. Here we show that chronic stress biases decision-making strategies in humans toward habits, as choices of stressed subjects become insensitive to changes in outcome value. Using functional imaging techniques, we demonstrate that prolonged exposure to stress in humans causes an imbalanced activation of the networks that govern decision processes, shifting activation from the associative to the sensorimotor circuits. These functional changes are paralleled by atrophy of the medial prefrontal cortex and the caudate, and by an increase in the volume of the putamina. Importantly, a longitudinal assessment of the stressed individuals showed that both the structural and functional changes triggered by stress are reversible and that decisions become again goal-directed.

Elbow kinematics after radiocapitellar arthroplasty

PURPOSE

Radiocapitellar arthroplasty has been proposed as a reconstructive option for combined radial head and capitellar deficiency. The purpose of this study was to assess the impact of radiocapitellar replacement on elbow kinematics. We hypothesized that with the medial collateral ligament (MCL) intact, radiocapitellar arthroplasty would replicate normal kinematics, and that a radiocapitellar arthroplasty would more closely approximate normal kinematics than an elbow with a deficient lateral column or with a deficient MCL.

METHODS

We tested 7 cadaveric arms in an upper extremity joint simulator. Each arm underwent computed tomographic scanning to aid implant size selection and computer-assisted implant insertion. We obtained kinematic data using an electromagnetic tracking system during elbow flexion. The capitellar and radial head implants were placed through an extended lateral epicondylar osteotomy. We sectioned the anterior bundle of the MCL, leaving the flexor-pronator mass intact. Outcomes of interest were varus-valgus and rotational kinematics of the ulnohumeral joint.

RESULTS

The radiocapitellar arthroplasty showed no difference in kinematics compared with the postosteotomy control. The MCL-deficient elbow showed more valgus angulation and more external ulnar rotation than the control or radiocapitellar arthroplasty in the pronated, valgus loaded position. The deficient lateral column demonstrated increased external ulnar rotation kinematics during active elbow flexion.

CONCLUSIONS

Radiocapitellar arthroplasty can restore normal elbow kinematics with the MCL intact. If the MCL is deficient, radiocapitellar arthroplasty does not restore normal kinematics.

CLINICAL RELEVANCE

Radiocapitellar arthroplasty should be considered in cases of lateral column deficiency because it maintains normal elbow kinematics during active motion. Whereas radiocapitellar arthroplasty improves the stability of the MCL-deficient elbow with deficiency of the lateral column, reconstruction of the MCL may further improve normal kinematics.

The impact of facial lipoatrophy treatment with polymethyl methacrylate in AIDS patients as measured by four quality-of-life questionnaires

Life-expectancy increased in patients infected with HIV/AIDS with the advent of highly active antiretroviral therapy (ART). Facial lipoatrophy is a common complication in these patients, eventually leading to stigma, segregation and a negative impact in quality of life (QOL). We measured the impact of the treatment of facial lipoatrophy with polymethyl methacrylate (PMMA) in the QOL of patients with HIV/AIDS by using four questionnaires that address QOL. Forty consecutive patients on ART referred for facial lipoatrophy treatment were enrolled in this study. The first 20 were allocated to the intervention group and were treated with tissue augmentation with PMMA. The other 20 were allocated to the control group, which received treatment only after six months. At baseline, four questionnaires were applied to all patients in both groups and again after six months. The variation in scores within the control group for all domains of all four instruments was significantly better when compared with that within the control group. We detected improvement in the QOL of patients with HIV/AIDS and facial lipoatrophy when they were treated with PMMA.

Antioxidant activity of unexplored indole derivatives: synthesis and screening

The present study envisaged the development of novel antioxidant candidates using the indole scaffold. Several tryptophan and tryptamine derivatives were synthesized, in particular prenylated indole compounds, and their scavenging activity for reactive oxygen species (ROS) and reactive nitrogen species (RNS) was investigated. The library substitution pattern included several alkyl chains at positions N-1, C-2 of the indole nucleus, including prenyl and isopentyl chain, as well as different groups at the side chain (C-3) that allowed the investigation of a possible radical stabilization. The results obtained showed that tryptophan (8), tryptamine (9), N-phthaloyl tryptamine (5) and N-prenyl tryptophan (13) were the most active against peroxyl radical (ROO(•)) with activities higher than Trolox, which was used as control. The scavenging of hypochlorous acid (HOCl) was also evaluated and tryptophan (8) and tryptamine (9) showed IC(50) of 3.50 ± 0.4 and 6.00 ± 0.60 μM, respectively. Significant activity was also found for the N-prenyl tryptophan (13) with an IC(50) of 4.13 ± 0.17 μM and C-2 prenylated derivative (14), with 4.56 ± 0.48 μM. The studies were extended to RNS and best results were obtained against peroxynitrite anion (ONOO(-)) in the presence of NaHCO(3). N-alkylated tryptophan (18) showed a high activity with an IC(50) of 14.0 ± 6.8 μM. The results show that the tested compounds are effective scavengers of ROS and RNS, and suggest that the radical stabilization is strongly dependent on the type of substituents on the indolic moiety and on their relative positions. In addition, the radical dissipation inside the indolic system is mandatory for the observed antioxidant activity.

Analysis of pharmacodynamic interaction of sevoflurane and propofol on Bispectral Index during general anaesthesia using a response surface model

BACKGROUND

Propofol and sevoflurane act on the GABA(A) receptor, modulating the function of this receptor in an additive manner. The pharmacodynamic interaction of both drugs considering their effect on EEG activity analysed by the bispectral index (BIS) was identified as additive, but this has not been studied in a clinical setting. The objective of this study was to analyse the pharmacodynamic interaction of propofol and sevoflurane on BIS using a surface response model in patients undergoing general anaesthesia with i.v. induction and inhalation maintenance.

METHODS

We performed a prospective study in 24 patients undergoing general anaesthesia with propofol induction and sevoflurane maintenance. Anaesthetic depth was measured with a BIS VISTA Bilateral monitor. Propofol biophase concentration was determined using a three-compartment pharmacokinetic model, and sevoflurane end-tidal concentration was measured continuously. The response surface model described by Minto and colleagues was used to analyse the interaction. Statistical analysis was performed with Excel 2002 and SPSS v11.0.

RESULTS

The mean value of U(50)(theta) was 0.956 (sd 0.029) in the overall estimated data, and remained within the predefined range for all ratios of the drugs, fulfilling the criterion of additivity. The median of the weighted residuals between the actual BIS value and the BIS value predicted by the model was -5.926%.

CONCLUSIONS

Under the study conditions, it was confirmed that sevoflurane and propofol have an additive effect on BIS, with no evidence suggesting the existence of a synergistic effect for the concentrations of both drugs typically used in clinical practice.

The effect of surface area digitizations on the prediction of spherical anatomical geometries for computer-assisted applications

Intraoperative digitization of osseous structures is an integral component of computer-assisted orthopaedic surgery. This study determined the repeatability and accuracy of predicting known radii and center locations of spherical objects for different proportions of digitized surface areas and various sphere sizes. Also, we investigated these accuracies for some relevant near-spherical osseous structures where results from full area digitizations were considered to be true. Digitizations were performed using an electromagnetic tracker with a stylus on the total and fractional surfaces of 10 hemispheres, ranging from 10 to 28mm in radius. Repeatability was quantified by digitizing five trials of the entire surface and various fractional areas of selected hemisphere sizes. Similar trials were conducted on models of a humeral and femoral head, using the full head area as baseline and digitizing 15 and 30mm diameter areas of the full head. Mean error for the predicted radii and center positions of the hemispheres ranged from 0.39+/-0.29 to 0.14+/-0.07mm and 0.52+/-0.31 to 0.22+/-0.12mm, respectively. Repeatability for the predicted radii and centers produced maximum standard deviations of 0.31 and 0.42mm, respectively. All errors decreased as fractional area (40%, 60%, 80% and 100%) increased (p<0.05). Radius of curvature and center position errors for the humeral head model were 1.51+/-2.11 and 2.28+/-1.51mm, respectively. These errors for the femoral head model were 3.37+/-4.14 and 4.25+/-4.14mm, respectively. Errors resulting from the prediction of radius and center indicate that non-spherical anatomical structures are more sensitive to the digitized area, and hence digitization of the largest surface possible seems warranted.

Inhibition of proliferation of Pseudomonas aeruginosa by KGF in an experimental burn model using human cultured keratinocytes

Experimental models showed the ability of Pseudomonas aeruginosa to interact with epidermal keratinocytes [Green H, Kehinde O, Thomas J. Growth of cultured human epidermal cells into multiple epithelia suitable for grafting. Proc Natl Acad Sci USA 1979;76(11):5665-8], stimulating these cells to produce specific peptides that start an immunological chain reaction in the epidermis [O'Connor NE, Mulliken JB, Banks-Schlegel S, Kehinde O, Green H. Grafting of burns with cultured epithelium prepared from autologous epidermal cells. Lancet 1981;(1):75-8]. The immune reaction causes the release of cytokines and growth factors. The objective of this study was to test whether the presence of keratinocyte growth factor (KGF) alters P. aeruginosa proliferation in an experimental burn model.

METHODS

Human keratinocytes derived from neonatal foreskins were isolated and cultured following standard methods [Gallico III, GG, O'Connor NE, Compton CC, Kehinde O, Green H. Permanent coverage of large burn wounds with autologous cultured human epithelium. N Engl J Med 1984;311(7):448-51]. Some of these cells were genetically modified to produce KGF, and the other cells were supplemented with different KGF concentrations in the culture media. Both groups of keratinocytes were seeded in collagen matrices and cultured to form stratified epithelia. A hot plate was used to produce burn defects. Each matrix was inoculated with luminescent P. aeruginosa strain. Experiments were made using keratinocytes without KGF, keratinocytes supplemented with different concentrations of KGF, and keratinocytes genetically modified to produce KGF. Statistical analyses were made using Wilcoxon paired test.

RESULTS

When KGF was added to P. aeruginosa in the presence of keratinocytes, bacterial growth was inhibited, and the same was observed when genetically modified keratinocytes were used.

CONCLUSION

Many studies have been done on KGF, where its known properties were defined as a mitogen for keratinocytes [Munster AM. Cultured skin for massive burns: a prospective, controlled trial. Ann Surg 1996;224(3):372-7]. This method allows for a qualitative and quantitative evaluation in real time of the bacterial growth in wound sites after bacterial inoculation. KGF was involved in the reduction of bacterial viability. However, as KGF alone did not produce any effect on P. aeruginosa, it seems to modulate the skin innate immune response.

Neurotoxicity mechanisms of thioether ecstasy metabolites

3,4-Methylenedioxymethamphetamine (MDMA or "ecstasy"), is a widely abused, psychoactive recreational drug that is known to induce neurotoxic effects. Human and rat hepatic metabolism of MDMA involves N-demethylation to 3,4-methylenedioxyamphetamine (MDA), which is also a drug of abuse. MDMA and MDA are O-demethylenated to N-methyl-alpha-methyldopamine (N-Me-alpha-MeDA) and alpha-methyldopamine (alpha-MeDA), respectively, which are both catechols that can undergo oxidation to the corresponding ortho-quinones. Ortho-quinones may be conjugated with glutathione (GSH) to form glutathionyl adducts, which can be transported into the brain and metabolized to the correspondent N-acetylcysteine (NAC) adducts. In this study we evaluated the neurotoxicity of nine MDMA metabolites, obtained by synthesis: N-Me-alpha-MeDA, alpha-MeDA and their correspondent GSH and NAC adducts. The studies were conducted in rat cortical neuronal cultures, for a 6 h of exposure period, under normal (36.5 degrees C) and hyperthermic (40 degrees C) conditions. Our findings show that thioether MDMA metabolites are strong neurotoxins, significantly more than their correspondent parent catechols. On the other hand, N-Me-alpha-MeDA and alpha-MeDA are more neurotoxic than MDMA. GSH and NAC conjugates of N-Me-alpha-MeDA and alpha-MeDA induced a concentration dependent delayed neuronal death, accompanied by activation of caspase 3, which occurred earlier in hyperthermic conditions. Furthermore, thioether MDMA metabolites time-dependently increased the production of reactive species, concentration-dependently depleted intracellular GSH and increased protein bound quinones. Finally, thioether MDMA metabolites induced neuronal death and oxidative stress was prevented by NAC, an antioxidant and GSH precursor. This study provides new insights into the neurotoxicity mechanisms of thioether MDMA metabolites and highlights their importance in "ecstasy" neurotoxicity.

Initial 200 cases of carotid artery stenting using a reversal-of-flow cerebral protection device

AIM

Because embolic complications can occur during carotid angioplasty and stenting (CAS), a new device, the Parodi Anti-Emboli System (PAES) was developed to protect the brain from embolization. We describe our initial experience with this device.

METHODS

Between September 1999 and December 2003, CAS was performed in 200 consecutive patients (146 men; mean age, 70.4 years) with symptomatic (52%) or asymptomatic (48%) severe carotid artery stenosis (>70%). De novo lesions were present in 169 patients, restenosis in 18, and radiation-induced stenosis in 13. Wallstents were inserted in all cases, with selective predilatation, and the PAES was employed during all CAS procedures. Patients were evaluated by a neurologist before and after CAS. Minor strokes, major or fatal strokes, and myocardial infarctions that occurred within 30 days of the procedure were recorded.

RESULTS

The overall technical success rate for CAS using the PAES (with the PAES placed in position percutaneously) was 99%. The overall perioperative stroke and death rate was 1.5%. There were four transient neurologic events after CAS, three of which were related to hemodynamic instability and one to postoperative embolization.

CONCLUSIONS

Our experience indicates that CAS using the PAES is safe and effective. The protection device may prevent the debris released by angioplasty from entering the cerebral circulation. Additional studies of this device are warranted.

Health-related quality of life of primary caregivers of persons with paraplegia

STUDY DESIGN

A cross-sectional descriptive study was performed with structured questionnaires and interviews conducted with 60 primary caregivers of persons with paraplegia (T1 to S2) owing to traumatic spinal cord injury (SCI).

OBJECTIVES

The purpose of this study was the assessment of the health-related quality of life (HRQoL) of primary caregivers of persons with paraplegia owing to traumatic SCI.

SETTING

São Paulo, SP, Brazil.

METHODS

The HRQoL was assessed by the Short Form-36 (SF-36) health survey questionnaire and caregiver burden was evaluated by the Caregiver Burden Scale (CBS).

RESULTS

Among 60 caregivers evaluated, 49 (81.7%) were female, with mean age of 35.8 (SD=12.91) years, 16 (26.6%) being wives and 14 (23.4%) sisters of persons with paraplegia. It was found that the caregivers spend an average of 11.3 h/day caring for individuals with paraplegia. Twenty-three caregivers (38.3%) had a chronic disease and 32 (53.3%) were sole caregivers taking upon themselves the full responsibility of caring for the persons with paraplegia. The subjects reported lower scores on bodily pain and vitality than the other dimensions of the SF-36. The mean global CBS score was 1.71 (SD=0.50) and mean scores for each dimension ranged from 1.39 (SD=0.64) for emotional involvement to 2.44 (SD=0.79) for environment dimension.

CONCLUSION

The primary caregivers of spinal cord-injured persons reported low scores on all of the SF-36 and CBS dimensions, bodily pain and vitality being the SF-36 dimensions that received the lowest scores.

Thermolysin in human cultured keratinocyte isolation

BACKGROUND: When treating extensively burned patients using cultured epidermal sheets, the main problem is the time required for its production. Conventional keratinocyte isolation is usually done using Trypsin. We used a modification of the conventional isolation method in order to improve this process and increase the number of colonies from the isolated epidermal cell population. PURPOSE: To compare the action of trypsin and thermolysin in the keratinocyte isolation using newborn foreskin. METHODS: This method used thermolysin as it selectively digests the dermo-epidermal junction. After dermis separation, the epidermis was digested by trypsin in order to obtain a cell suspension. RESULTS: Compared to the conventional procedure, these experiments demonstrated that in the thermolysin group, the epidermis was easily detached from the dermis, there was no fibroblast contamination and there were a larger number of keratinocyte colonies which had a significant statistical difference. CONCLUSION: The number of colonies in the thermolysin group was significantly greater than in the trypsin group.

Reconstruction technique for umbilical endometriosis

OBJECTIVE

To present a technique for immediate umbilical reconstruction in women undergoing resection of umbilical endometriosis.

METHODS

Umbilical reconstruction using 2 semicircular defatted skin flaps was performed in 7 patients surgically treated for umbilical endometriosis from October 2000 to June 2004. The patients were followed up for at least 6 months.

RESULTS

Anatomical aspect, depression, and abdominal wall scar were considered satisfactory, although hypertrophic umbilical scars developed in 2 patients.

CONCLUSION

This technique using 2 semicircular defatted flaps is efficient in creating a new umbilicus with a natural appearance while leaving a minimal scar. Moreover, it allows for laparoscopic inspection of the abdominal cavity.

Phytate technetium-99m versus dextran 500 technetium-99m in the sentinel lymph node biopsy

PURPOSE

To study which of the two most used radiopharmaceutical drugs for the sentinel lymph node (SLN) biopsy procedure (dextran 500 99mTc and phytate 99mTc) best defines the SLN and migrates less to other lymph nodes.

MATERIAL AND METHODS

Thirty-two rats, separated into two groups, underwent lymphoscintigraphy examination with either dextran or phytate followed by sentinel (popliteal), lumbar, and inguinal lymph node biopsy. Radiation was detected with a gamma probe.

RESULTS

The statistical study indicated count rates significantly higher in the SLN than in the other basins for both the dextran (P<0.01) and phytate groups (P<0.001). There was no statistically significant difference concerning SLN absorption in either group (P=0.2981). In the dextran group, migration occurred to 1.5 lymphatic basins with counting higher than 10% of that found in the SLN versus 0.8 in the phytate group (P=0.0023). Migration was thus higher in the dextran group (P=0.0207).

CONCLUSION

There was no statistically significant difference between dextran and phytate in the SLN identification, but the phytate migrated to fewer lymphatic basins beyond the SLN and with less intensity.

Quality of life outcomes after pedicled TRAM flap delayed breast reconstruction

OBJECTIVES

To evaluate the impact of TRAM flap delayed breast reconstruction on health related quality of life in patients who had undergone mastectomy.

METHODS

Twenty-five patients following mastectomy were selected consecutively from the Plastic Surgery/Mastology Units of two university hospitals. All subjects underwent breast reconstruction with the use of pedicled TRAM flap. The patients' health related quality of life was assessed by a validated instrument, the SF-36 Health Survey Questionnaire. This was applied preoperatively and postoperatively at 3, 6 and 12-months follow-up. A group of 20 women with mastectomies who have not undergone breast reconstruction was used as a control. To assess patients' satisfaction with breast reconstruction we used Alderman's modified general satisfaction subscale.

RESULTS

There was a progressive improvement in all dimensions of the SF-36, and this was statistically significant for seven of the eight dimensions. The scores were significantly higher on 'role emotional' and 'mental health' at 3 months postoperatively, on 'health perception' and 'role physical' at month 6 and on 'physical function', 'pain', health perception and 'social function' at postoperative month 12. Despite the increase in scores, no significant changes in 'vitality' were found. There was no significant preoperative difference between the control group and studied patients, and the control group's scores were significantly lower in all dimensions when compared to postoperative month 12, except on 'physical function'. The level of patients' satisfaction with the TRAM flap breast reconstruction was high.

CONCLUSIONS

The data of this study suggest that delayed breast reconstruction with the use of the pedicled TRAM flap provides an improvement in health related quality of life of patients who have undergone mastectomy.

Vertical growth phase and positive sentinel node in thin melanoma

Sentinel node (SN) status is the most important prognostic factor for localized melanoma. Usually, patients with Breslow thickness of less than 1.0 mm are not included in SN protocols. However, the literature presents a rate ranging from 3 to 7% of nodal recurrence in thin melanoma. Ulceration, regression and high mitotic rate have been considered to be indications for an SN biopsy. The metastatic potential of the vertical growth phase is uncertain. To correlate pathological features in thin melanoma with SN metastasis, we reviewed 358 patients submitted to SN biopsy. Seventy-seven patients with lesions of 1 mm or smaller were included in the study group. Histological evaluation of the primary tumor included thickness, Clark level, mitotic rate, ulceration, regression, and growth phase. Lymphoscintigraphy was performed on all patients. Lymphatic mapping and gamma probe detection were both used for SN biopsy. Histological examination of SN consisted of hematoxylin-eosin and immunohistochemical staining. Median follow-up was 37 months. Six patients had micrometastases. Statistical analysis by the Fisher test showed that ulceration (P = 0.019), high mitotic rate (P = 0.008) and vertical growth phase (P = 0.002) were positively correlated with micrometastases. If other studies confirm these results, more melanoma patients must be submitted to SN biopsy.

Differentiation and barrier formation of a cultured composite skin graft

The differentiation and barrier formation of cultured composite skin grafts (CSGs) were assessed by histology and measurements of surface electrical capacitance (SEC) in vitro and in vivo. Keratinocytes cultured on the surface of acellular dermis were lifted to the air-liquid interface and analyzed for 30 days in vitro. Initially, SEC measurements of CSGs (n = 11) were high but quickly dropped between days 4 and 6 and remained steady for 30 days, indicating barrier formation by the epidermis. Histology of the CSGs (n = 6) demonstrated stratification of the epidermal cells and partial formation of the stratum corneum by day 3 that was complete by day 7. CSGs (n = 5) were transplanted to athymic mice, where they formed a stratified and differentiated epidermis. SEC measurements of CSGs remained low after transplant, suggesting that exposure to the air-liquid interface improved the maturation of CSGs in vitro prior to transplant.

The location of the ligand-binding site of carbohydrate-binding modules that have evolved from a common sequence is not conserved

Polysaccharide-degrading enzymes are generally modular proteins that contain non-catalytic carbohydrate-binding modules (CBMs), which potentiate the activity of the catalytic module. CBMs have been grouped into sequence-based families, and three-dimensional structural data are available for half of these families. Clostridium thermocellum xylanase 11A is a modular enzyme that contains a CBM from family 6 (CBM6), for which no structural data are available. We have determined the crystal structure of this module to a resolution of 2.1 A. The protein is a beta-sandwich that contains two potential ligand-binding clefts designated cleft A and B. The CBM interacts primarily with xylan, and NMR spectroscopy coupled with site-directed mutagenesis identified cleft A, containing Trp-92, Tyr-34, and Asn-120, as the ligand-binding site. The overall fold of CBM6 is similar to proteins in CBM families 4 and 22, although surprisingly the ligand-binding site in CBM4 and CBM22 is equivalent to cleft B in CBM6. These structural data define a superfamily of CBMs, comprising CBM4, CBM6, and CBM22, and demonstrate that, although CBMs have evolved from a relatively small number of ancestors, the structural elements involved in ligand recognition have been assembled at different locations on the ancestral scaffold.

The structure of the feruloyl esterase module of xylanase 10B from Clostridium thermocellum provides insights into substrate recognition

BACKGROUND

Degradation of the plant cell wall requires the synergistic action of a consortium of predominantly modular enzymes. In Clostridiae, these biocatalysts are organized into a supramolecular assembly termed a "cellulosome." This multienzyme complex possesses, in addition to its well-described cellulolytic activity, an apparatus specific for xylan degradation. Cinnamic acid esterases hydrolyze the ferulate groups involved in the crosslinking of arabinoxylans to lignin and thus play a key role in the degradation of the plant cell wall in addition to having promising industrial and medical applications.

RESULTS

We have cloned and overexpressed the feruloyl esterase module from a 5 domain xylanase, Xyn10B from Clostridium thermocellum. The native structure at 1.6 A resolution has been solved with selenomethionine multiple wavelength anomalous dispersion and refined to a final R(free) of 17.8%. The structure of a hydrolytically inactive mutant, S954A, in complex with the reaction product ferulic acid has been refined at a resolution of 1.4 A with an R(free) of 16.0%.

CONCLUSIONS

The C. thermocellum Xyn10B ferulic acid esterase displays the alpha/beta-hydrolase fold and possesses a classical Ser-His-Asp catalytic triad. Ferulate esterases are characterized by their specificity, and the active center reveals the binding site for ferulic acid and related compounds. Ferulate binds in a small surface depression that possesses specificity determinants for both the methoxy and hydroxyl ring substituents of the substrate. There appears to be a lack of specificity for the xylan backbone, which may reflect the intrinsic chemical heterogeneity of the natural substrate.

Reduction of AOX in the bleach plant of a pulp mill

The reconfiguration of an existing five-stage bleaching D0E1D1E2D2 sequence is proposed to ensure the minimal formation of organochlorine compounds, expressed as AOX, in the bleach plant of a kraft pulp mill processing Eucalyptus globulus wood. This reduction of the load of AOX in the effluents can be achieved without introducing new and expensive technologies in the bleaching process. In practice, this goal can be achieved by eliminating the washing step between the D0 and the E1 stages. With this strategy, the total AOX in the liquid effluent of the bleach plant can be reduced by almost 65% while maintaining a level of 90% ISO brightness of the pulp and even diminishing the degradation of its polysaccharides. With this process redesign, the total AOX discharge from the bleach plant can be decreased from 1.2 to 0.42 kg/t prior to any biological treatment. Furthermore, the proposed modified (D0E1)D1E2D2 sequence enables the reduction of the total flow rate of effluent to be treated and also the total consumption of water, which is quite critical in these types of plants. Moreover, with this strategy, one is able to move the first drum washer of a conventional bleaching sequence to the entrance of the bleach plant. This gives rise to a cleaner pulp and therefore to lower requirements of chlorine dioxide, which in turn will enable further reductions in the global AOX generation.

Intra-aneurysmal pressure after incomplete endovascular exclusion

PURPOSE

An endoleak results from the incomplete endovascular exclusion of an aneurysm. We developed an experimental model to analyze hemodynamic changes within the aneurysm sac in the presence of an endoleak, with and without a simulated open collateral branch.

METHODS

With a latex aneurysm model connected to a pulsatile pump, pressures were measured simultaneously within the system (systemic pressure) and the aneurysm sac (intrasac pressure). The experiments were performed without endoleak (control group) and after creating a 3.5-mm (group 1), 4.5-mm (group 2), and 6-mm (group 3) diameter orifice in the endograft, simulating an endoleak. Pressures were also registered with and without a patent aneurysm side branch.

RESULTS

In each endoleak group, the intrasac diastolic pressure (DP) and mean pressure (MP) were significantly higher than the systemic DP and MP (P =.01, P =.006, and P =.001, respectively), although the pressure curve was damped. The presence of an open side branch significantly reduced the intrasac DP and MP.

CONCLUSION

In this model, intrasac pressures were significantly higher than systemic pressures in the presence of all endoleaks, even the smallest ones. Intrasac pressures higher than systemic pressure may pose a high risk for aneurysm rupture. Although patent side branches significantly reduce these pressures, the aggressive management of an endoleak should be pursued.

[Clinical application of the V-Y posterior thigh fasciocutaneous flap]

PURPOSE

To analyze the clinical applicability of one-stage treatment of single or multiple sores using the V-Y posterior thigh fasciocutaneous flap.

METHODS

Twenty patients were treated, having 25 ulcers in the gluteal and perineal regions, being 23 pressure ulcers, 1 perianal abscess and 1 perineal trauma. In all of the patients the repair was carried out with a fasciocutaneous flap from the posterior region of the thigh. The flap was made with a superior and lateral base, preserving the fasciocutaneous branches of the inferior gluteal arteries, first and second perforating, in the treatment of ischial ulcers. In the associations of the same with sacral ulcer, a fasciocutaneous extension from the gluteal region was added to the flap for a one and only surgical procedure. A superior and medial based flap was made, preserving the fasciocutaneous branch of the inferior gluteal artery in the treatment of the trochanteric ulcers. In the associations with sacral ulcer a fasciocutaneous extension from the gluteal region was added to the posterior thigh flap which permitted the closure of all ulcers in only one surgical procedure. In the associations of trochanteric and ischial ulcers a flap with a superior base was made, preserving the fasciocutaneous branch of the inferior gluteal artery.

RESULTS

There was no necrosis of the flap. The immediate complications were 3 infections, 1 dehiscences and 1 hematoma. In a follow-up period of 6 months to 29 months, with one patient being lost to follow up, there were 6 recurrences 6/24 (25.0%) in 5 patients 5/19 (26.32%).

CONCLUSION

We conclude that the posterior fasciocutaneous thigh flap, in V-Y, can be used with safety in the treatment of isolated or multiple ulcers in the gluteal and perineal regions.

Clostridium thermocellum Xyn10B carbohydrate-binding module 22-2: the role of conserved amino acids in ligand binding

The majority of plant cell wall hydrolases are modular enzymes which, in addition to a catalytic module, possess one or more carbohydrate-binding modules (CBMs). These carbohydrate-active enzymes and their constituent modules have been classified into a number of families based upon amino acid sequence similarity. The Clostridium thermocellum xylanase, Xyn10B, contains two CBMs that belong to family 22 (CBM22). The crystal structure of the C-terminal CBM22 (CBM22-2) was determined in a previous study [Charnock, S. J., et al. (2000) Biochemistry 39, 5013--5021] and revealed a surface cleft which presents several conserved residues that are implicated in ligand binding. These amino acids have been substituted and the structure and biochemical properties of the mutants analyzed. The data show that R25A, W53A, Y103A, Y136A, and E138A exhibit greatly reduced affinity for xylotetraose relative to that of the wild-type protein. Conversely, mutations Y103F and Y136F have little effect on ligand binding. Using thermodynamic, X-ray, and NMR measurements on the mutants, we show that the cleft of CBM22-2 does indeed form the ligand-binding site. Trp 53 and Tyr 103 most likely participate in hydrophobic stacking interactions with the ligand, while Glu 138 makes one or more important hydrogen bonds with the tetrasaccharide. Although Arg 25 and Tyr 136 are likely to form hydrogen bonds with the ligand, they are also shown to play a critical role in maintaining the structural integrity of the binding cleft.

Brown pigments produced by Yarrowia lipolytica result from extracellular accumulation of homogentisic acid

Yarrowia lipolytica produces brown extracellular pigments that correlate with tyrosine catabolism. During tyrosine depletion, the yeast accumulated homogentisic acid, p-hydroxyphenylethanol, and p-hydroxyphenylacetic acid in the medium. Homogentisic acid accumulated under all aeration conditions tested, but its concentration decreased as aeration decreased. With moderate aeration, equimolar concentrations of alcohol and p-hydroxyphenylacetic acid (1:1) were detected, but with lower aeration the alcohol concentration was twice that of the acid (2:1). p-Hydroxyphenylethanol and p-hydroxyphenylacetic acid may result from the spontaneous disproportionation of the corresponding aldehyde, p-hydroxyphenylacetaldehyde. The catabolic pathway of tyrosine in Y. lipolytica involves the formation of p-hydroxyphenylacetaldehyde, which is oxidized to p-hydroxyphenylacetic acid and then further oxidized to homogentisic acid. Brown pigments are produced when homogentisic acid accumulates in the medium. This acid can spontaneously oxidize and polymerize, leading to the formation of pyomelanins. Mn(2+) accelerated and intensified the oxidative polymerization of homogentisic acid, and lactic acid enhanced the stimulating role of Mn(2+). Alkaline conditions also accelerated pigment formation. The proposed tyrosine catabolism pathway appears to be unique for yeast, and this is the first report of a yeast producing pigments involving homogentisic acid.

Production of brown tyrosine pigments by the yeast Yarrowia lipolytica

AIMS

To study the mechanism of production of brown pigments from tyrosine in the yeast Yarrowia lipolytica.

METHODS AND RESULTS

Pigment formation was followed during growth in tyrosine medium, and the presence of the pigment precursor in the medium was assessed by evaluating pigment formation after removing the cells at different times of incubation. It was observed that the pigment precursor accumulated outside the cells during the exponential phase of growth, but pigment formation only occurred during the stationary phase of growth and resulted from the oxidation of the precursor. Pigment formation was repressed by glucose and L-glutamine, and promoted by lactic acid, L-asparagine and glycine. Spectra of 1H and 13C-NMR revealed that the brown pigment was derived from tyrosine and was a polymer composed of a core of aromatic residues.

CONCLUSION

The results indicate that pigments result from the extracellular accumulation and auto-oxidation of an intermediate of tyrosine catabolism.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report on the mechanism of pigment production from tyrosine in a yeast species.

Triangular mattress suture in abdominal diastasis to prevent epigastric bulging

In the classic abdominoplasty, the treatment of large diastasis recti with simple or vertical mattress sutures may result in a nonaesthetic bulge. The surgeon may produce a craniocaudal bulge deformity by treating the flaccidity in the horizontal plane only, although it occurs in all directions. The authors describe the triangular mattress suture for the treatment of large diastasis recti, and demonstrate the mechanism involved in producing an epigastric bulge. Also presented is their clinical experience with 56 patients, with a 3-year follow-up, using this new plication method. The triangular mattress suture is a simple, quick, and effective way to correct abdominal diastasis and to avoid the epigastric bulge deformity with no added morbidity.

Reduction of intraspecific aggression in adult rats by neonatal treatment with a selective serotonin reuptake inhibitor

Most studies suggest that serotonin exerts an inhibitory control on the aggression process. According to experimental evidence, this amine also influences growth and development of the nervous tissue including serotoninergic neurons. Thus, the possibility exists that increased serotonin availability in young animals facilitates a long-lasting effect on aggressive responses. The present study aimed to investigate the aggressive behavior of adult rats (90-120 days) treated from the 1st to the 19th postnatal day with citalopram (CIT), a selective serotonin reuptake inhibitor (20 mg/kg, s.c., every 3 days). Aggressive behavior was induced by placing a pair of rats (matched by weight) in a box (20 x 20 x 20 cm), and submitting them to a 20-min session of electric footshocks (five 1.6-mA - 2-s current pulses, separated by a 4-min intershock interval). When compared to the control group (rats treated for the same period with equivalent volumes of saline solution), the CIT group presented a 41.4% reduction in the duration of aggressive response. The results indicate that the repeated administration of CIT early in life reduces the aggressive behavior in adulthood and suggest that the increased brain serotoninergic activity could play a role in this effect.

Initial evaluation of carotid angioplasty and stenting with three different cerebral protection devices

OBJECTIVE

The purpose of the study was to assess the effectiveness of cerebral protection devices during carotid artery angioplasty and stent placement.

METHODS

Between September 1998 and September 1999, carotid angioplasty and stenting were performed in 46 patients with symptomatic (39.1%) or asymptomatic (60.9%) severe carotid artery stenosis. Wallstents were used in all patients with selective predilatation. Cerebral protection devices were used in 25 of these patients. Primary end points were perioperative neurologic complications and mortality. Data were collected prospectively.

RESULTS

The overall combined end point of all neurologic deficits and death rate was 4.34%. Two neurologic events (one transient ischemic attack and one minor stroke) occurred in the unprotected group (9.53%) versus none in the group with cerebral protection. This difference is not statistically significant. The mortality rate was 0% for both groups. On an intention to treat basis, the overall technical success rate for carotid angioplasty was 97.8%, and for placement of cerebral protection devices it was 100%. An important number of particles of different sizes were captured in all cases in which cerebral protection devices were used.

CONCLUSION

Experience has shown that cerebral protection during carotid angioplasty and stenting is technically feasible and appears to be effective in preventing procedure-related neurologic complications. Further investigation is warranted.