Biomechanical and histological evaluation of hydrogel implants in articular cartilage

We evaluated the mechanical behavior of the repaired surfaces of defective articular cartilage in the intercondylar region of the rat femur after a hydrogel graft implant. The results were compared to those for the adjacent normal articular cartilage and for control surfaces where the defects remained empty. Hydrogel synthesized by blending poly(2-hydroxyethyl methacrylate) and poly(methyl methacrylate-co-acrylic acid) was implanted in male Wistar rats. The animals were divided into five groups with postoperative follow-up periods of 3, 5, 8, 12 and 16 weeks. Indentation tests were performed on the neoformed surfaces in the knee joint (with or without a hydrogel implant) and on adjacent articular cartilage in order to assess the mechanical properties of the newly formed surface. Kruskal-Wallis analysis indicated that the mechanical behavior of the neoformed surfaces was significantly different from that of normal cartilage. Histological analysis of the repaired defects showed that the hydrogel implant filled the defect with no signs of inflammation as it was well anchored to the surrounding tissues, resulting in a newly formed articular surface. In the case of empty control defects, osseous tissue grew inside the defects and fibrous tissue formed on the articular surface of the defects. The repaired surface of the hydrogel implant was more compliant than normal articular cartilage throughout the 16 weeks following the operation, whereas the fibrous tissue that formed postoperatively over the empty defect was stiffer than normal articular cartilage after 5 weeks. This stiffness started to decrease 16 weeks after the operation, probably due to tissue degeneration. Thus, from the biomechanical and histological point of view, the hydrogel implant improved the articular surface repair.

Bariatric and Post-Bariatric Surgery: from Metabolic Surgery to Plastic Surgery Indications

Background: Controversy exists concerning indications and outcomes of major bariatric surgery procedures. Massive weight loss after bariatric surgery leads to excess skin with functional and aesthetic impairments. The aim of this study was to investigate the major bariatric surgery procedures and their outcomes in two specific subgroups of morbidly obese patients, ≥55-year-olds and the superobese. Further aims were to evaluate whether the preoperative weight loss correlates with laparoscopic gastric bypass complications. The prevalence and impact of excess skin and the desire for body contouring after bariatric surgery were also studied. Patients and Methods: Data from patients who underwent Laparoscopic Adjustable Gastric Banding (LAGB) and Laparoscopic Roux-en-Y Gastric Bypass (LRYGB) at Vaasa Central Hospital were collected and postoperative outcomes were evaluated according to the BMI, age and preoperative weight loss. Patients who had undergone bariatric surgery procedures were asked to complete a questionnaire to estimate any impairment due to redundant skin and to analyse each patient’s desire for body contouring by area. Results: No significant difference was found in operative time, hospital stay, or overall early postoperative morbidity between LAGB and LRYGB. Mean excess weight loss percents (EWL%) at 6 and 12 months after LRYGB were significantly higher. A significant difference was found in operative time favouring patients <55 years. Intraoperative complications were significantly more frequent in the group aged >55 years. No significant difference was detected in overall postoperative morbidity rates. A significant difference was found in operative time and hospital stay favouring all patients who lost weight preoperatively. Most patients reported problems with redundant skin, especially on the abdomen, upper arms and rear/buttocks, which impaired daily physical activity in half of them. Excess skin was significantly associated with female gender, weight loss and ΔBMI. Patients with a WL >20 kg, ΔBMI ≥10 kg/m2 and an EWL % > 50 showed a significantly surplus skin discomfort (p < 0.001). Most patients desired body contouring surgery, with high or very high desire for waist/abdomen (62.2%), upper arm (37.6%), chest/breast (28.3%), and rear/buttock (35.6%) contouring. Conclusions: LRYGB is effective and safe in superobese (BMI >50) and elderly (>55 years) patients. A preoperative weight loss >5% is recommended to improve the outcomes and reduce complications. A WL >20 kg, ΔBMI ≥10 kg/m2 and an EWL % > 50 are associated with a higher functional discomfort due to redundant skin and to a stronger desire for body contouring plastic surgery.

Transitory increased blood pressure after upper airway surgery for snoring and sleep apnea correlates with the apnea-hypopnea respiratory disturbance index

A transitory increase in blood pressure (BP) is observed following upper airway surgery for obstructive sleep apnea syndrome but the mechanisms implicated are not yet well understood. The objective of the present study was to evaluate changes in BP and heart rate (HR) and putative factors after uvulopalatopharyngoplasty and septoplasty in normotensive snorers. Patients (N = 10) were instrumented for 24-h ambulatory BP monitoring, nocturnal respiratory monitoring and urinary catecholamine level evaluation one day before surgery and on the day of surgery. The influence of postsurgery pain was prevented by analgesic therapy as confirmed using a visual analog scale of pain. Compared with preoperative values, there was a significant (P < 0.05) increase in nighttime but not daytime systolic BP (119 ± 5 vs 107 ± 3 mmHg), diastolic BP (72 ± 4 vs 67 ± 2 mmHg), HR (67 ± 4 vs 57 ± 2 bpm), respiratory disturbance index (RDI) characterized by apnea-hypopnea (30 ± 10 vs 13 ± 4 events/h of sleep) and norepinephrine levels (22.0 ± 4.7 vs 11.0 ± 1.3 µg l-1 12 h-1) after surgery. A positive correlation was found between individual variations of BP and individual variations of RDI (r = 0.81, P < 0.01) but not between BP or RDI and catecholamines. The visual analog scale of pain showed similar stress levels on the day before and after surgery (6.0 ± 0.8 vs 5.0 ± 0.9 cm, respectively). These data strongly suggest that the cardiovascular changes observed in patients who underwent uvulopalatopharyngoplasty and septoplasty were due to the increased postoperative RDI.

Cardiac and vascular effects of diltiazem, dobutamine and amrinone, drugs used after myocardial revascularization

Hemodynamic care during postoperative management of myocardial revascularization should include vasorelaxing drugs to insure adequate graft and coronary flow, and stimulation of stroke volume to maintain vascular perfusion pressure. We tested the cardiac (inotropic and lusitropic) and vascular (relaxant) effects of diltiazem (0.1 nM to 0.1 mM), dobutamine (10 µM to 10 mM) and amrinone (10 µM to 1 mM) on isolated rat atria and thoracic aorta, and also on isolated human saphenous vein (HSV) and human mammary artery (HMA). Dobutamine produced a maximal positive inotropic effect (+dF/dt max = 29 ± 7%) at its ED50 for aortic relaxation (88 ± 7 µM). Conversely, at their ED50 for aortic relaxation diltiazem depressed myocardial contractility and amrinone did not exhibit myocardial effects. In HSV and HMA contracted with 80 mM potassium, diltiazem and dobutamine (but not amrinone) had a vasorelaxant activity similar to that in rat aorta. Norepinephrine-contracted human vessels were significantly more sensitive than potassium-contracted vessels to the relaxant effect of amrinone (ED50 HMA = 15 ± 5 µM, ED50 HSV = 72 ± 31 µM, P < 0.05). We conclude that at concentrations still devoid of myocardial effects dobutamine and amrinone are effective dilators in graft segment vessels and rat aorta contracted by membrane depolarization. If the difference between aortic and myocardial tissue still holds in human tissues, at the appropriate concentrations these drugs should be expected to improve cardiac performance while still contributing to the maintenance of graft patency.

Twenty-four-hour esophageal pH monitoring in children and adolescents with chronic and/or recurrent rhinosinusitis

Gastroesophageal reflux (GER) disorder was studied in children and adolescents with chronic and/or recurrent rhinosinusitis not associated with bronchial asthma. Ten children with a clinical and radiological diagnosis of chronic and/or recurrent rhinosinusitis, consecutively attended at the Pediatric Otolaryngology Outpatient Clinic, Federal University of São Paulo, were evaluated. Prolonged esophageal pH monitoring was used to investigate GER disorder. The mean age of the ten patients evaluated (eight males) was 7.4 ± 2.4 years. Two patients presented vomiting as a clinical manifestation and one patient presented retrosternal pain with a burning sensation. Twenty-four-hour esophageal pH monitoring was performed using the Sandhill apparatus. An antimony probe electrode was placed in the lower third of the esophagus, confirmed by fluoroscopy and later by a chest X-ray. The parameters analyzed by esophageal pH monitoring included: total percent time of the presence of acid esophageal pH, i.e., pH below 4 (<4.2%); total number of acid episodes (<50 episodes); number of reflux episodes longer than 5 min (3 or less), and duration of the longest reflux episode (<9.2 min). One patient (1/10, 10%) presented a 24-h esophageal pH profile compatible with GER disorder. This data suggest that an association between chronic rhinosinusitis not associated with bronchial asthma and GER disorder may exist in children and adolescents, especially in those with compatible GER disorder symptoms. In these cases, 24-h esophageal pH monitoring should be performed before indicating surgery, since the present data suggest that 10% of chronic rhinosinusitis surgeries can be eliminated.

Relative frequency, clinical, neuroimaging, and postsurgical features of pediatric temporal lobe epilepsy

We describe the relative frequency, clinical features, neuroimaging and pathological results, and outcome after pharmacological or surgical intervention for a series of pediatric patients with temporal lobe epilepsy (TLE) from an epilepsy center in Brazil. The medical records of children younger than 12 years with features strongly suggestive of TLE were reviewed from January 1999 to June 1999. Selected children were evaluated regarding clinical, EEG, and magnetic resonance imaging (MRI) investigation and divided into three groups according to MRI: group 1 (G1, N = 9), patients with hippocampal atrophy; group 2 (G2, N = 10), patients with normal MRI, and group 3 (G3, N = 12), patients with other specific temporal lesions. A review of 1732 records of children with epilepsy revealed 31 cases with TLE (relative frequency of 1.79%). However, when the investigation was narrowed to cases with intractable seizures that needed video-EEG monitoring (N = 68) or epilepsy surgery (N = 32), the relative frequency of TLE increased to 19.11 (13/68) and 31.25% (10/32), respectively. At the beginning of the study, 25 of 31 patients had a high seizure frequency (80.6%), which declined to 11 of 31 (35.5%) at the conclusion of the study, as a consequence of pharmacological and/or surgical therapy. This improvement in seizure control was significant in G1 (P < 0.05) and G3 (P < 0.01) mainly due to good postsurgical outcome, and was not significant in G2 (P > 0.1, McNemar's test). These results indicate that the relative frequency of TLE in children was low, but increased considerably among cases with pharmacoresistant seizures. Patients with specific lesions were likely to undergo surgery, with good postoperative outcomes.

Effect of cardiopulmonary bypass on the pharmacokinetics of propranolol and atenolol

The pharmacokinetics of some β-blockers are altered by cardiopulmonary bypass (CPB). The objective of this study was to compare the effect of coronary artery bypass graft (CABG) surgery employing CPB on the pharmacokinetics of propranolol and atenolol. We studied patients receiving oral propranolol with doses ranging from 80 to 240 mg (N = 11) or atenolol with doses ranging from 25 to 100 mg (N = 8) in the pre- and postoperative period of CABG with moderately hypothermic CPB (32°C). On the day before and on the first day after surgery, blood samples were collected before β-blocker administration and every 2 h thereafter. Plasma levels were determined using high-performance liquid chromatography and data were treated by pharmacokinetics-modelling. Statistical analysis was performed using ANOVA or the Friedman test, as appropriate, and P < 0.05 was considered to be significant. A prolongation of propranolol biological half-life from 5.41 ± 0.75 to 11.46 ± 1.66 h (P = 0.0028) and an increase in propranolol volume of distribution from 8.70 ± 2.83 to 19.33 ± 6.52 L/kg (P = 0.0032) were observed after CABG with CPB. No significant changes were observed in either atenolol biological half-life (from 11.20 ± 1.60 to 11.44 ± 2.89 h) or atenolol volume of distribution (from 2.90 ± 0.36 to 3.83 ± 0.72 L/kg). Total clearance was not changed by surgery. These CPB-induced alterations in propranolol pharmacokinetics may promote unexpected long-lasting effects in the postoperative period while the effects of atenolol were not modified by CPB surgery.

Plasmatic ADAMTS-13 metalloprotease and von Willebrand factor in children with cyanotic congenital heart disease

Changes in plasma von Willebrand factor concentration (VWF:Ag) and ADAMTS-13 activity (the metalloprotease that cleaves VWF physiologically) have been reported in several cardiovascular disorders with prognostic implications. We therefore determined the level of these proteins in the plasma of children with cyanotic congenital heart disease (CCHD) undergoing surgical treatment. Forty-eight children were enrolled (age 0.83 to 7.58 years). Measurements were performed at baseline and 48 h after surgery. ELISA, collagen-binding assays and Western blotting were used to estimate antigenic and biological activities, and proteolysis of VWF multimers. Preoperatively, VWF:Ag and ADAMTS-13 activity were decreased (65 and 71% of normal levels considered as 113 (105-129) U/dL and 91 ± 24% respectively, P < 0.003) and correlated (r = 0.39, P = 0.0064). High molecular weight VWF multimers were not related, suggesting an interaction of VWF with cell membranes, followed by proteolytic cleavage. A low preoperative ADAMTS-13 activity, a longer activated partial thromboplastin time and the need for cardiopulmonary bypass correlated with postoperative bleeding (P < 0.05). Postoperatively, ADAMTS-13 activity increased but less extensively than VWF:Ag (respectively, 2.23 and 2.83 times baseline, P < 0.0001), resulting in an increased VWF:Ag/ADAMTS-13 activity ratio (1.20 to 1.54, respectively, pre- and postoperative median values, P = 0.0029). ADAMTS-13 consumption was further confirmed by decreased ADAMTS-13 antigenic concentration (0.91 ± 0.30 to 0.70 ± 0.25 µg/mL, P < 0.0001) and persistent proteolysis of VWF multimers. We conclude that, in pediatric CCHD, changes in circulating ADAMTS-13 suggest enzyme consumption, associated with abnormal structure and function of VWF.

Effects of bromopride on expression of metalloproteinases and interleukins in left colonic anastomoses: an experimental study

Anastomotic dehiscence is the most severe complication of colorectal surgery. Metalloproteinases (MMPs) and interleukins (ILs) can be used to analyze the healing process of anastomosis. To evaluate the effects of bromopride on MMP and cytokine gene expression in left colonic anastomoses in rats with or without induced abdominal sepsis, 80 rats were divided into two groups for euthanasia on the third or seventh postoperative day (POD). They were then divided into subgroups of 20 rats for sepsis induction or not, and then into subgroups of 10 rats for administration of bromopride or saline. Left colonic anastomosis was performed and abdominal sepsis was induced by cecal ligation and puncture. A colonic segment containing the anastomosis was removed for analysis of gene expression of MMP-1α, MMP-8, MMP-13, IL-β, IL-6, IL-10, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ). On the third POD, bromopride was associated with increased MMP-1α, MMP-13, IL-6, IFN-γ, and IL-10 gene expression. On the seventh POD, all MMP transcripts became negatively modulated and all IL transcripts became positively modulated. In the presence of sepsis, bromopride administration increased MMP-8 and IFN-γ gene expression and decreased MMP-1, TNF-α, IL-6, and IL-10 gene expression on the third POD. On the seventh POD, we observed increased expression of MMP-13 and all cytokines, except for TNF-α. In conclusion, bromopride interferes with MMP and IL gene expression during anastomotic healing. Further studies are needed to correlate these changes with the healing process.

Abundant immunohistochemical expression of dopamine D2 receptor and p53 protein in meningiomas: follow-up, relation to gender, age, tumor grade, and recurrence

Meningiomas are common, usually benign tumors, with a high postoperative recurrence rate. However, the genesis and development of these tumors remain controversial. We aimed to investigate the presence and implications of a mutated p53 protein and dopamine D2 receptor in a representative series of meningiomas and to correlate these findings with age, gender, tumor grade, and recurrence. Tumor tissue samples of 157 patients diagnosed with meningioma (37 males and 120 females, mean age 53.6±14.3 years) who underwent surgical resection between 2003 and 2012 at our institution were immunohistochemically evaluated for the presence of p53 protein and dopamine D2 receptor and were followed-up to analyze tumor recurrence or regrowth. Tumors were classified as grades I (n=141, 89.8%), II (n=13, 8.3%), or grade III (n=3, 1.9%). Dopamine D2 receptor and p53 protein expression were positive in 93.6% and 49.7% of the cases, respectively. Neither of the markers showed significant expression differences among different tumor grades or recurrence or regrowth statuses. Our findings highlight the potential role of p53 protein in meningioma development and/or progression. The high positivity of dopamine D2 receptor observed in this study warrants further investigation of the therapeutic potential of dopamine agonists in the evolution of meningiomas.

Diabetes mellitus affects the biomechanical function of the callus and the expression of TGF-beta1 and BMP2 in an early stage of fracture healing

Transforming growth factor beta 1 (TGF-β1) and bone morphogenetic protein-2 (BMP-2) are important regulators of bone repair and regeneration. In this study, we examined whether TGF-β1 and BMP-2 expressions were delayed during bone healing in type 1 diabetes mellitus. Tibial fractures were created in 95 diabetic and 95 control adult male Wistar rats of 10 weeks of age. At 1, 2, 3, 4, and 5 weeks after fracture induction, five rats were sacrificed from each group. The expressions of TGF-β1 and BMP2 in the fractured tibias were measured by immunohistochemistry and quantitative reverse-transcription polymerase chain reaction, weekly for the first 5 weeks post-fracture. Mechanical parameters (bending rigidity, torsional rigidity, destruction torque) of the healing bones were also assessed at 3, 4, and 5 weeks post-fracture, after the rats were sacrificed. The bending rigidity, torsional rigidity and destruction torque of the two groups increased continuously during the healing process. The diabetes group had lower mean values for bending rigidity, torsional rigidity and destruction torque compared with the control group (P<0.05). TGF-β1 and BMP-2 expression were significantly lower (P<0.05) in the control group than in the diabetes group at postoperative weeks 1, 2, and 3. Peak levels of TGF-β1 and BMP-2 expression were delayed by 1 week in the diabetes group compared with the control group. Our results demonstrate that there was a delayed recovery in the biomechanical function of the fractured bones in diabetic rats. This delay may be associated with a delayed expression of the growth factors TGF-β1 and BMP-2.

Comparison of totally tubeless percutaneous nephrolithotomy and standard percutaneous nephrolithotomy for kidney stones: a randomized, clinical trial

This study aimed to compare the totally tubeless percutaneous nephrolithotomy and standard percutaneous nephrolithotomy techniques regarding their rates of success and complications in patients with kidney stones. Patients were randomly assigned to two groups. Forty-four patients (24 men; mean age: 50.40±2.02 years) received totally tubeless percutaneous nephrolithotomy (PCNL; no nephrostomy catheter or ureteral catheter after PCNL) and 40 patients (18 men; mean age: 49.95±13.38 years) underwent standard PCNL (a nephrostomy catheter and ureteral catheter were used after PCNL). All surgeries were performed by one surgeon. Postoperative changes in hemoglobin, the blood transfusion rate, changes in creatinine levels, operation time, analgesic need, hospitalization time, and complication rate were compared between the groups. No significant differences were observed in age, gender, stone size, and surgery side between the groups (P<0.05). The operation time was significantly lower in the totally tubeless PCNL group than in the standard PCNL group (P=0.005). Pethidine requirements were significantly higher in the standard PCNL group than the totally tubeless PCNL group (P=0.007). Hospitalization time was significantly higher in the standard PCNL group than in the totally tubeless PCNL group (P<0.0001). The complication rate was 15% in the standard PCNL group and 9.1% in the totally tubeless PCNL group (P=0.73). The totally tubeless PCNL technique is safe and effective, even for patients with staghorn stones. This technique is associated with decreased pain, analgesic needs, and operative and hospitalization time. We believe that a normal peristaltic ureter is the best drainage tube.

Preoperative education and its influence on perception of recovery for clients awaiting total hip and total knee replacement surgery /

The puqjose of this study was to examine the manner in which an inviting approach to a preoperative teaching and learning educational experience influenced the perception and subsequent recovery of clients who were awaiting total hip and total knee replacement surgery. An in-depth review of the internal and external factors that shape client perceptions was undertaken in this study. In addition, this study also explored whether or not the Prehab Program was preparing clients physically, socially, and psychologically for surgery. Data for this qualitative case study research were collected through preoperative interviews with 4 participants awaiting total hip replacement surgery and 1 participant awaiting total knee replacement surgery. Four postoperative interviews were conducted with the participants who had received total hip replacement surgery. The occupational therapist and physical therapist who were the coleaders of the Prehab Program at the time of this study were also interviewed. The results of this study suggest that while individuals may receive similar educational experiences, their perceptions of the manner in which they benefited from these experiences varied. This is illustrated in the research findings, which concluded that while clients benefited physically from the inviting approach used during the practical teaching session, not all clients perceived the psychological benefits of this practice session, especially clients with preexisting high levels of anxiety. In addition to increasing the understanding of the internal as well as external factors that influence the perceptions of clients, this study has also served as an opportunity for reflection on practice for the Prehab therapists and other healthcare educators.

Intraoperative hemodynamic instability during and after separation from cardiopulmonary bypass : importance, mechanism and prevention

Chaque année, environ 1 à 1,25 million d’individus subiront une chirurgie cardiaque. [1] Environ 36 000 chirurgies cardiaques sont effectuées au Canada et 8000 procédures au Québec (http://www.ccs.ca). Le vieillissement de la population aura pour conséquence que la chirurgie cardiaque sera offerte à des patients de plus en plus à risque de complications, principalement en raison d’une co-morbidité plus importante, d’un risque de maladie coronarienne plus élevée, [2] d’une réserve physiologique réduite et par conséquent un risque plus élevé de mortalité à la suite d’une chirurgie cardiaque. L’une des complications significatives à la suite d’une chirurgie cardiaque est le sevrage difficile de la circulation extracorporelle. Ce dernier inclut la période au début du sevrage de la circulation extracorporelle et s’étend jusqu’au départ du patient de la salle d’opération. Lorsque le sevrage de la circulation extracorporelle est associé à une défaillance ventriculaire droite, la mortalité sera de 44 % à 86 %. [3-7] Par conséquent le diagnostic, l’identification des facteurs de risque, la compréhension du mécanisme, la prévention et le traitement du sevrage difficile de la circulation extracorporelle seront d’une importance majeure dans la sélection et la prise en charge des patients devant subir une chirurgie cardiaque. Les hypothèses de cette thèse sont les suivantes : 1) le sevrage difficile de la circulation extracorporelle est un facteur indépendant de mortalité et de morbidité, 2) le mécanisme du sevrage difficile de la circulation extracorporelle peut être approché d’une façon systématique, 3) la milrinone administrée par inhalation représente une alternative préventive et thérapeutique chez le patient à risque d’un sevrage difficile de la circulation extracorporelle après la chirurgie cardiaque.

Therapeutic potential of endothelin receptor type A and bradykinin receptor B1 dual antagonism in osteoarthritis treatment

Nous avons préalablement démontré que l'endothéline-1 (ET-1), un peptide vasoconstricteur de 21 acides aminés, joue un rôle central dans le métabolisme des tissus articulaires et a des fonctions cataboliques sur le cartilage articulaire dans l'ostéoarthrose, en liant son récepteur de type A (ETA). Suite à la relâche du nonapeptide vasodilatateur bradykinine (BK), et l'augmentation d'expression du récepteur B1 des kinines (BKB1), ces médiateurs engendrent un cycle d'inflammation, une destruction du cartilage, et une douleur articulaire. Lors de cette étude, l'efficacité thérapeutique des antagonistes spécifiques du ETA et/ou BKB1 dans un modèle animal d'ostéoarthrose a été testée. Notre hypothèse est que l'antagonisme va diminuer la progression de la pathologie et de la douleur articulaire. L'ostéoarthrose a été induite chez des rats par rupture chirurgicale du ligament croisé antérieur. Les animaux ont été traités par injections intra articulaire hebdomadaires des antagonistes peptidiques spécifiques du ETA et/ou BKB1. La douleur articulaire a été évaluée par le test d'incapacitance statique durant les deux mois postopératoires ; la morphologie articulaire a été examinée post mortem par radiologie et histologie. On constate que le traitement a diminué la douleur et a préservé la morphologie articulaire ; la double inhibition a été plus efficace que la simple inhibition. En conclusion, l'antagonisme double d'ETA et BKB1 améliore la douleur chronique et prévient la dégradation articulaire dans l'ostéoarthrose, ce qui suggère que ces récepteurs peuvent être des cibles thérapeutiques potentiels pour le traitement de cette pathologie.