Liver resection safety in a developing country: Analysis of a collective learning curve.

AIM OF THE STUDY: To analyze the collective learning curve in the performance of safe liver resections, using the decrease of severe postoperative complications (SPC) as a proxy for overall safety competency. MATERIAL AND METHODS: This was a retrospective analysis of a prospective database in the setting of a liver surgery program implementation in a tertiary center in Morocco. The 100 first consecutive cases of elective liver resections starting from January 1st, 2018 were included in the analysis. SPC were defined as CD>IIIa during the first 90 postoperative days. We used a cumulative sum (CUSUM) technique to determine the number of cases required to achieve safety competency. We then compared case characteristics before and after the learning curve completion. RESULTS: SPC occurred in 15 cases (15%), including 5 deaths (5%). The CUSUM chart revealed a learning curve completion at the 49th case, marked by an inflection point towards the decrease in SPC (24.5% vs 5.9%; P=0.009). In period 2 (after), cases were associated with less diabetes, less synchronous digestive resection, more cirrhosis, and more prolonged preoperative chemotherapy. The rates of major resection (30.6% vs 29.9%; P=0.89) and biliary reconstruction were comparable, as were the operating time, and estimated blood loss. CONCLUSION: Approximately 50 cases were required to complete the learning curve and improve the overall safety of liver resection. In our setting, the learning curve chronology was consistent with collective measures, including team stabilization and protocol development.

Management of ventricular perforation during revascularization of an intramyocardial left anterior descending artery.

Ventricular perforation during exposure of an intramyocardial left anterior descending artery (LAD) in preparation for coronary artery bypass grafting is a known surgical complication. In this report, we discuss the management of this complication which avoids closure of the LAD and a myocardial infarction.

Utility of real-time three-dimensional echocardiography in improved assessment of a mitral valve papillary fibroelastoma.

Primary cardiac tumors are exceedingly rare. They are usually first identified by transthoracic echocardiography. However, transesophageal echocardiography (TEE), with the aid of real-time three-dimensional (3D) imaging, can provide additional important mass characteristics. We present a case that demonstrates the usefulness of 3D TEE in characterizing a papillary fibroelastoma.

Effect of bulk-fill base material on fracture strength of root-filled teeth restored with laminate resin composite restorations.

OBJECTIVES: To evaluate the effect of using a bulk-fill flowable base material on fracture strength and fracture patterns of root-filled maxillary premolars with MOD preparations restored with laminate restorations. METHODS: Fifty extracted maxillary premolars were selected for the study. Standardized MOD cavities with endodontic treatment were prepared for all teeth, except for intact control. The teeth were divided randomly into five groups (n=10); (Group 1) sound teeth, (Group 2) unrestored teeth; (Group 3) MOD cavities with Vitrebond base and resin-based composite (Ceram. X One Universal); (Group 4) MOD cavities with 2mm GIC base (Fuji IX GP) and resin-based composite (Ceram. X One Universal) open laminate, (Group 5) MOD cavities were restored with 4mm of bulk-fill flowable base material (SDR) and resin-based composite (Ceram. X One Universal). All teeth were thermocycled and subjected to a 45° ramped oblique load in a universal testing machine. Fracture load and fracture patterns were recorded. Data were analyzed using one-way ANOVA and Dunnett's T3 test. RESULTS: Restoration in general increased the fracture strength compared to unrestored teeth. The fracture strength of group 5 (bulk-fill) was significantly higher than the fracture strength of the GIC laminate groups and not significantly different from the intact teeth (355±112N, P=0.118). The type of failure was unfavorable for most of the groups, with the majority being mixed failures. CONCLUSIONS: The use of a bulk-fill flowable base material significantly increased the fracture strength of extracted root-filled teeth with MOD cavities; however it did not improve fracture patterns to more favorable ones. CLINICAL SIGNIFICANCE: Investigating restorative techniques that may improve the longevity of root-filled premolar teeth restored with direct resin restorations.

Occult Internal Mammary Artery Neurofibromatosis: A Case for Caution in Coronary Revascularization.

Intrathoracic neurofibromas are relatively uncommon in patients with neurofibromatosis. They are usually asymptomatic and may be discovered incidentally. We present the case of a 51-year-old, African American man with neurofibromatosis type 1 who underwent coronary revascularization. Intraoperatively, numerous neurofibromas were discovered, one of which was attached to the left internal mammary artery. The procedure was uncomplicated despite the challenging intraoperative findings. Special considerations in the management of patients with neurofibromatosis undergoing cardiac surgery are discussed, including risks, preoperative imaging and the importance of excision of suspicious tumors.

The Anomalous Coronary Artery in Aortic Valve Replacement: A Case For Caution.

We report obstruction of an anomalous right coronary artery traversing between the pulmonary artery and aorta after placement of a 21-mm bovine bioprosthesis for critical aortic stenosis requiring emergency revascularization. Although this anomaly has been associated with sudden death syndrome, acute coronary ischemia resulting from aortic valve replacement in patients with anomalous coronary artery has not been sufficiently highlighted in the literature. Awareness of this issue may decrease the risk of this complication in patients with anomalous coronary anatomy undergoing aortic or pulmonary valve replacement. Furthermore, the need for careful preoperative imaging in patients undergoing semilunar valve replacement is essential.

[The aneurysms of the aorta of tuberculous]. / Les anévrysmes de l'aorte d'origine tuberculeuse. À propos de trois cas.

Tuberculosis is a public health problem in Morocco, which is difficult to eradicate despite the recognized efficiency of health policies. Aortic aneurysm is rare and lethal complication of spontaneous evolution. Pathophysiological characteristics and the difficulty of early diagnosis worsen the prognosis.

C1 inhibitor function using contact-phase proteases as target: evaluation of an innovative assay.

BACKGROUND: Controlling prekallikrein activation by C1 inhibitor (C1Inh) represents the most essential mechanism for angioedema patient protection. C1Inh function in the plasma is usually measured based on the residual activity of the C1s protease not involved in the pathological process. We have hereby proposed an alternative enzymatic measurement of C1Inh function based on contact-phase activation and correlation with angioedema diagnostic requirements. METHODS: The contact phase was reconstituted using the purified components, with C1Inh standard or plasma sample. The kinetics of the amidase activity were monitored using Pro-Phe-Arg-pNA, independently of alpha2-macroglobulin. We prevented any interference from a possible high plasma kininogenase activity by preincubating the samples with protease inhibitor. Receiver operating characteristics (ROC) were used to calculate the assay's diagnostic performance. RESULTS: The calibration curve was built using C1Inh standard (threshold limit 0.10 × 10(-3) U, i.e., 0.2 pmol), and C1Inh function was quantified in the sample, with a reference interval established based on healthy individuals (n = 281; men: 0.61-1.10 U/ml, median: 0.85 U/ml; women: 0.42-1.08 U/ml, median: 0.74 U/ml). The median values of female donors were lower than those of the others due to estrogen, yet C1Inh function remained within the reference interval. The ROC curve calculation provided the following optimum diagnostic cutoff values: women 0.36 U/ml (area under curve [AUC]: 0.99; sensitivity: 93.48%; specificity: 99.37%); and men 0.61 U/ml (AUC: 1; sensitivity: 100.0%; specificity: 100.0%). CONCLUSION: The performance outcome provided features suitable for angioedema diagnostic or follow-up. Established by means of the kinin formation process, this assay should be preferred over the method based on a C1s protease target.

[Biological investigation of kinin-mediated angioedema]. / Exploration biologique des angiœdèmes à kinines.

Kinin-mediated angioedema results from accumulation of kinins, vasoactive and vasopermeant peptides, on the vascular endothelium. The disease is characterized by sudden episodes of swelling in the subcutaneous and submucosal tissues; the edema may occur spontaneously or it may be precipitated by triggering factors such as physical or emotional stress, or certain medicines. The characterization of kinin formation and catabolism systems helps improve knowledge of the aetiopathogenic mechanisms involved and provides the basis for classification of kinin-mediated angioedema conditions; thus, we may distinguish between angioedema with C1 inhibitor deficiency, whether inherited or acquired, and angioedema with normal C1 inhibitor activity, associated with increased kinin-forming activity or deficiency in kinin catabolism enzymes. In support of the clinical diagnosis, the physician may request laboratory investigation for a functional and molecular definition of the disease. Laboratory diagnosis is based on the characterization of: (1) kinin production control by C1 inhibitor investigation (function, antigen levels and circulating species); (2) kinin production (kininogenase activity, kininogen cleavage species); and (3) kinin catabolism enzymes (aminopeptidase P, carboxypeptidase N, angiotensin-I converting enzyme and dipeptidyl peptidase IV). An abnormal biological phenotype is supported by examination of susceptibility genes (SERPING1, F12 and XPNPEP2) and mutation segregation in the families.

Hereditary angioedema with F12 mutation: factors modifying the clinical phenotype.

BACKGROUND: Hereditary angioedema (HAE) with normal C1 inhibitor (C1Inh) associated with the c.983C>A and c.983C>G mutations of the F12 gene (FXII-HAE) is a rare condition, and presents with highly variable clinical expression. On the basis of data gathered from a large carrier cohort, we assessed the modifiers affecting the clinical phenotype. METHODS: We analyzed clinical and biological data recorded from 118 mutation carriers (80 symptomatic and 38 asymptomatic), 58 noncarrier relatives from 40 families, and 200 healthy donors. Disease severity was scored in relation to frequency and location of edema, as well as age at disease onset. To predict FXII-HAE disease severity, we analyzed the biological phenotype [C1Inh, C4, spontaneous amidase, angiotensin-I-converting enzyme (ACE), aminopeptidase P (APP), and carboxypeptidase N/M (CPN)] by means of logistic regression (Akaike information criterion) and odds ratio (OR). RESULTS: Meaningful variables contributed to FXII-HAE, with the kinin catabolism enzymes ACE and CPN exhibiting a significant inverse relationship with disease severity (OR = 0.36, 95% CI 0.23-0.59, P < 0.001; OR = 0.58, 95% CI 0.36-0.91, P < 0.05, respectively). CPN activities were 37.5 (28.5-41.3) nmol/ml/min and 38.5 (32.8-45.6) for FXII-HAE asymptomatic and symptomatic carriers, respectively, and 37.9 (30.5-43.7) nmol/ml/min for noncarriers. Angiotensin-I-converting enzyme activities were 58 (44-76) and 49 (35-59) nmol/ml/min for FXII-HAE asymptomatic and symptomatic carriers, respectively, and 56 (49-66) nmol/ml/min for noncarriers. CONCLUSIONS: The FXII-HAE is associated with modifiers, for example kinin catabolism enzymes, ACE and CPN, different from those recognized in HAE with C1Inh deficiency.

[Medication errors in anesthesia: a Moroccan university hospitals survey]. / Erreurs médicamenteuses en anesthésie : enquête prospective au niveau des CHU Marocains.

INTRODUCTION: Medication errors are a major public health problem because of their morbidity and financial costs. In anesthesia, few articles publications, mostly retrospective, have assessed its incidence and outcomes. By our prospective study, we intend to identify and describe the drug errors in anesthesia in four university hospitals in Morocco. MATERIAL AND METHODS: After approval of our ethics committee, a prospective study was conducted in nine hospitals affiliated to four university hospitals (Rabat, Casablanca, Fes and Marrakech) from October 2009 to June 2010. Data collection was carried out by an anesthesiologist at each hospital who was designated by the investigator. Informations were based on practitioner's statements. Medication errors were divided into distinct categories: substitution errors, omission errors, errors of the way of administration, dosage and dilution errors. The consequences were classified into four levels according to their severity. RESULTS: During the study period, 9199 anesthetic procedures were reported (mean response of 36%). General anesthesia was performed in 75% of patients. Sixteen cases of drug errors were reported (an incidence of 1/575 with 1/405 in a pediatric setting). The drugs involved were dominated by hypnotics (six cases/16) and morphine (four cases/16). Medication errors were mainly due to labeling mistakes (seven cases/16) and to attention deficit due to fatigue and stress (seven other cases) leading to substitution error in most of cases (10 cases/16. Errors were mainly made by the less experienced practitioners (14 cases/16). They occurred during the induction phase (seven cases/16) as well as during the interview process (nine cases/16), and also during emergent surgeries (seven errors/16) as well as during elective ones (nine errors/16). No errors caused death. Pulmonary edema (recognized as a grade III severity incident) was secondary to inappropriate administration of adrenaline. CONCLUSION: Our study helped us to set recommendations, which are approved by the Moroccan pharmacovigilance center, and in accordance with the international committees to prevent the occurrence of medication errors in our daily anesthetic practice.

Effects of Cu-doping on the magnetic state of Zn(0.9-x)Fe0.1Cu(x)O.

Magnetization measurements were performed on a series of Zn(0.9-x)Fe0.1Cu(x)O samples (0 < x approximately 0.1) prepared using solid state reaction and sol-gel methods. Although Cu is nonmagnetic, we found that increasing Cu content increases the saturation magnetization and enhances the hysteresis losses. Curie behavior of the susceptibility at high temperature indicates the presence of ferromagnetic exchange interaction. Moreover, we found that the exchange interaction and the molecular field coefficient are both ferromagnetic and greatly enhanced with Cu-doping; however, the Arrott-Belov-Kouvel plot did not reveal the presence of spontaneous magnetization down to 4.2 K.

[Anaphylactic shock in surgery of liver hydatid cyst in children: a case report]. / Choc anaphylactique au cours de la chirurgie du kyste hydatique du foie chez l'enfant : à propos d'un cas.

The hydatid disease is common and remains endemic in Morocco. The treatment relies mainly on surgery. This may be accompanied by rare but serious complications that can certainly be life-threatening. Allergic reactions can manifest as anaphylactic shock which is characterized by its brutal onset and its severity. We stress through the pediatric case reported the exceptional occurrence of anaphylactic shock during surgery and the need for its early recognition in order to establish effective treatment. Prevention relies mainly on surgical precautions taken to avoid seeding of the abdominal cavity.

Effect of bioactive ceramic dissolution on the mechanism of bone mineralization and guided tissue growth in vitro.

A major objective of this research work was to evaluate the effect of bone cells on the dissolution-precipitation reaction in vitro. Rat bone marrow stem cells were seeded on silica-calcium phosphate nano composite (SCPC) with different chemical compositions and crystalline structures. Measurements of the Ca, P, Si, and Na concentrations in the tissue culture media using inductively coupled plasma indicated that bone marrow stem cells attached to the surface of SCPC did not affect the dissolution behavior of the material. However, bone marrow stem cells interfered with the back precipitation reaction and inhibited the formation of a calcium phosphate (Ca-P) layer on the material surface. Scanning electron microscope-energy-dispersive X-ray analyses showed that, in the absence of cells, a Ca-P layer formed on the material surface because of the dissolution-precipitation reaction. Bone cells attached to SCPC that contains high silica content absorbed significantly higher concentrations of medium Ca than cells attached to SCPC that contains low silica content. In conjunction with the absorption of high Ca concentration, attached bone marrow stem cells produced calcified nodules and mineralized extracellular matrix, indicating osteoblastic differentiation. Results of the study strongly suggest that the mechanism of bone mineralization at the interface with bioactive ceramics is mainly cell mediated and is enhanced by the absorption of critical concentrations of dissolved Ca and P. The silicon-rich phase also provided a guided cell adhesion and tissue growth in vitro. The enhanced bioactivity reactions and strong stimulatory effect on bone cell function are attributed to the modified crystalline structure of the SCPC material.

Effects of silica on the bioactivity of calcium phosphate composites in vitro.

In the present study, silica-calcium phosphate composites (SiO(2)-CaP composites) were developed by mixing the starting materials (SiO(2) and CaHPO(4)) in different ratios with the addition of 0.1% w/v NaOH solution. The phase composition of the SiO(2)-CaP composites was determined by XRD and FTIR. After thermal treatment at 350 degrees C/1 h and at 1000 degrees C/3.5 h; all SiO(2)-CaP composites composed of beta-quartz, alpha-cristobalite and beta-Ca2P2O7. The presence of calcium phosphate enhanced the transformation of beta-quartz into alpha-cristobalite at 1000 degrees C. SEM observation indicated favorable attachment and spreading of neonatal rat calvaria osteoblasts onto the surface of silica-rich SiO(2)-CaP composites. After attachment, these cells produced significantly higher amount of protein and expressed higher AP activity than cells attached to silica-poor samples. Results of the study suggested that the silica-based composites are more bioactive than calcium phosphate-based composites. Silica promoted the expression of osteoblast phenotype by both solution-mediated effect and direct interaction with the surface of the substrate.

Cyclosilicate nanocomposite: a novel resorbable bioactive tissue engineering scaffold for BMP and bone-marrow cell delivery.

Porous bioactive resorbable silica-calcium phosphate nanocomposite (SCPC) was prepared by a sintering technique. XRD analyses showed that the main crystalline phases of the SCPC are Na(3)CaPSiO(7) (clinophosinaite), beta-NaCaPO(4) (rhenanite), Na(2)CaSiO(4), and beta-quartz (SiO(2)). The clinophosinaite is a novel cyclosilicate bioactive mineral that enhanced the mechanical and bioactivity properties of the SCPC. TEM analysis showed that the grain sizes of the multiphase SCPC are in the nanometer scale. Moreover, the SCPC was engineered with nano- and microscale porosity. The SCPC had significantly higher compressive strength than porous hydroxyapatite (HA). FTIR analyses revealed the formation of biological hydroxyapatite layer on the SCPC surface after 4 days of immersion in SBF. When SCPC was loaded with rhBMP-2, it provided a superior release profile of biologically active rhBMP-2 compared to porous HA. Bone-marrow cells incubated with medium treated with the rhBMP-2 released from the SCPC-rhBMP-2 hybrid expressed significantly higher alkaline phosphatase activity than that expressed by cells incubated with media treated with rhBMP-2 released from HA-rhBMP-2. In addition, cells attached to the SCPC-rhBMP-2 hybrid produced mineralized extracellular matrix (ECM) and bone-like tissue that covered the material surface and filled pores in the entire thickness of the template after 3 weeks in culture. In contrary, cells attached to the HA-rhBMP-2 produced limited amount of unmineralized ECM after the same time period. Results of the study strongly suggest that the porous bioactive silica-calcium phosphate nanocomposite can serve as a delivery system for cells and biological molecules. The SCPC-rhBMP-2-marrow cell hybrid may serve as an alternative to autologous bone grafting.

Model surfaces engineered with nanoscale roughness and RGD tripeptides promote osteoblast activity.

Cell adhesion to biomaterials is a prerequisite for tissue integration with the implant surface. Herein, we show that we can generate a model silica surface that contains a minimal-length arginine-glycine-aspartic acid (RGD) peptide that maintains its biological activity. In the first part of this study, attachment of MC3T3-E1 osteoblast-like cells was investigated on silicon oxide, amine terminated substrates [i.e., 3-aminopropyl triethoxysilane (APTS)], grafted RGD, and physisorbed RGD control. The APTS layer exhibited nanoscale roughness and presented amine functional groups for grafting a minimal RGD tripeptide devoid of any flanking groups or spacers. Contact angle measurements indicated that the hydrophobicity of the APTS surface was significantly lower than that of the surface with grafted RGD (RGD-APTS). Atomic force microscopy showed that surfaces covered with RGD-APTS were smoother (Ra = 0.71 nm) than those covered with APTS alone (Ra = 1.59 nm). Focusing mainly on cell morphology, experiments showed that the RGD-APTS hybrid provided an optimum surface for cell adhesion, spreading, and cytoskeletal organization. Discrete focal adhesion plaques were also observed consistent with successful cell signaling events. In a second set of experiments, smooth, monolayers of APTS (Ra = 0.1 nm) were used to prepare arginine-glycine-aspartic acid-serine (RGDS)-APTS and arginine-glycine-glutamic acid-serine (RGES)-APTS (control) substrates. Focusing mainly on cell function, integrin and gene expression were all enhanced for rate osteosarcoma cells on surfaces containing grafted RGDS. Both sets of studies demonstrated that grafted molecules of RGD(S) enhance both osteoblast-like cell adhesion and function.

Crystallization behavior of silica-calcium phosphate biocomposites: XRD and FTIR studies.

Silica and calcium phosphates (CaP) are the most important ingredients in bioactive materials that bond to bone and enhance bone tissue formation. In this study, silica-calcium phosphate (SiO2-CaP) composites were developed by powder metallurgy method, using silica (SiO2) and anhydrous dicalcium phosphate (CaHPO4) powders (CaP) in the ratios (wt%): 20/80, 40/60, 60/40 and 80/20. The effects of temperature and chemical composition on crystallization and phase transformation of the SiO2-CaP composites were evaluated by XRD and FTIR. Thermal treatment of the starting material suggested that CaHPO4 transforms into: gamma-Ca2P2O7 at 800 degrees C; beta-Ca2P2O7 at 1000 degrees C and alpha-Ca2P2O7 at 1200 degrees C. On the other hand, beta-quartz was the only detected phase after thermal treatment of silica in the temperature range 800-1200 degrees C. For all SiO2-CaP composites, SiO2 and CaP did not modify the crystallization behavior of each other when sintered in the temperature range 800-1000 degrees C. However, at 1200 degrees C, CaP promoted the transformation of gamma-quartz into alpha-cristobalite. Moreover, SiO2 stabilized beta-Ca2P2O7. The modifications in the crystallization behavior were related to ion substitution and formation of solid solutions.