Effect of synthetic bone replacement material of different size on shear stress resistance within impacted native and thermodisinfected cancellous bone: an in vitro femoral impaction bone grafting model.

Antibiotic carrier particles of variable size might influence mechanic properties within impacted thermodisinfected and native cancellous bone different. Herafill®G containing calciumsulfate and calciumcarbonate provides high local concentrations of gentamicin being important for revision surgery in infected joint replacements. Native and thermodisinfected cancellous bone derived from 6 to 7 months old piglets was used for in vitro impaction bone grafting and supplemented each with Herafill®G granules of two different sizes. Micromovement of implants related to shear force was measured in 29 specimens distributed in 6 groups. Thermodisinfected cancellous bone revealed a significant higher shear force resistance than native bone with a mean difference of 423.8 mdeg/Nm (p < 0.001) ranging within 95% confidence interval from 181.5 to 666.0 mdeg/Nm. Adding small granules to thermodisinfected bone did not reduce shear force resistance significantly since adding large granules to native bone improved it by 344.0 mdeg/Nm (p < 0.003). Shear force resistance was found higher at the distal region of the implant compared to a proximal point of measurement throughout all specimens. Less impaction impulses were necessary for thermodisinfected bone. Thermodisinfected cancellous bone might achieve a higher degree of impaction compared with native bone resulting in increased resistance against shear force since impaction was found increased distally. Supplementation of thermodisinfected bone with small granules of Herafill®G might be considered for application of local antibiotics. Large granules appeared more beneficial for supplementation of native bone. Heterogeneity of bone graft and technical aspects of the impaction procedure have to be considered regarding the reproducibility of femoral impaction bone grafting.

Foam front propagation in anisotropic oil reservoirs.

The pressure-driven growth model is considered, describing the motion of a foam front through an oil reservoir during foam improved oil recovery, foam being formed as gas advances into an initially liquid-filled reservoir. In the model, the foam front is represented by a set of so-called "material points" that track the advance of gas into the liquid-filled region. According to the model, the shape of the foam front is prone to develop concave sharply curved concavities, where the orientation of the front changes rapidly over a small spatial distance: these are referred to as "concave corners". These concave corners need to be propagated differently from the material points on the foam front itself. Typically the corner must move faster than those material points, otherwise spurious numerical artifacts develop in the computed shape of the front. A propagation rule or "speed up" rule is derived for the concave corners, which is shown to be sensitive to the level of anisotropy in the permeability of the reservoir and also sensitive to the orientation of the corners themselves. In particular if a corner in an anisotropic reservoir were to be propagated according to an isotropic speed up rule, this might not be sufficient to suppress spurious numerical artifacts, at least for certain orientations of the corner. On the other hand, systems that are both heterogeneous and anisotropic tend to be well behaved numerically, regardless of whether one uses the isotropic or anisotropic speed up rule for corners. This comes about because, in the heterogeneous and anisotropic case, the orientation of the corner is such that the "correct" anisotropic speed is just very slightly less than the "incorrect" isotropic one. The anisotropic rule does however manage to keep the corner very slightly sharper than the isotropic rule does.

Factors related to advanced colorectal neoplasm at the Policlínico Peruano Japonés.

BACKGROUND: Identifying persons at high risk for advanced colorectal neoplasia can aid in the prevention of colon cancer. Previous studies have shown that some patients can present with proximal advanced neoplasia with no distal findings. AIMS: To determine the factors related to advanced neoplasia and advanced proximal colorectal neoplasia in a Latin American population. MATERIAL AND METHODS: A prospective, cross-sectional, observational, analytic study was conducted. It included patients that underwent colonoscopy at the Policlínico Peruano Japonés within the time frame of January and July 2012. Advanced neoplasia was defined as the presence of lesions ≥ 10mm with a villous component, high-grade dysplasia, or carcinoma. The splenic flexure was the limit between the proximal and distal colon. RESULTS: A total of 846 patients were included in the study. Advanced neoplasia was detected in 108 patients (12.8%) and advanced proximal neoplasia in 55 patients (6.7%), 42 (76.4%) of whom had no neoplasia in the distal colon. Factors related to advanced neoplasia found in the multivariate analysis were age, at the intervals of 50-59 (p=0.019), 60-69 (p=0.016), and ≥ 70 years (0.002) and male sex (p=0.003). In the evaluation of advanced proximal neoplasia, the multivariate analysis identified the 60-69 year age interval (p=0.039) and advanced distal neoplasia (p=0.028) as factors related to advanced proximal disease. The ROC curve established the age cut-off point at 60 years for initially performing colonoscopy, rather than sigmoidoscopy. CONCLUSIONS: Age and sex are related to advanced neoplasia, whereas age and advanced distal neoplasia are related to advanced proximal neoplasia.

Palmitic acid coating of allogeneic cancellous bone for local antibiotic treatment: A porcine impaction bone grafting model.

Introduction: The worldwide rising number of joint replacements results in increasing revision surgery including a relevant portion of septic loosening accompanied by bone deficiencies. Loading of allogeneic bone with antibiotics provides high local antibiotic concentrations and might eradicate bacteria which appear resistant to systemic antibiotic application. Hydrophobic palmitic acid was shown to be a suitable carrier for antibiotics and prevents biofilm. Methods: Cancellous bone derived from 6 to 7 months old piglets was used for a standardized in vitro impaction bone grafting model according to previous studies. The specimens were either thermodisinfected or remained native and palmitic acid with one third and two third partial weight were added and compared with control. Shear force at the interface prosthesis to cement and between cement and bone was measured. The relative micromovements were measured with 6 inductive sensors with a resolution of 0.1 µm at three different measuring heights up to a maximum movement of 150 µm between cement and bone. Taking into account the corresponding applied torque the measured values were normalized in µm/Nm. Statistical analysis was done with SPSS Statistics® Version 26.0 IBM. Results: Smallest movement was measured for thermodisinfected cancellous bone and a not significant decrease of shear force resistance with addition of palmitic acid was found since supplementing native cancellous bone reduced shear force resistance significantly depending on the weight percentage of palmitic acid. Conclusion: Supplementation of porcine cancellous bone with palmitic acid did not significantly reduce shear force resistance of thermodisinfected bone since adding palmitic acid to native bone decreased it significantly depending on the volume added. Palmitic acid seems to be a suitable coating for allogeneic cancellous bone to deliver high local antibiotic concentrations and thermodisinfected cancellous bone might be able to store larger volumes of palmitic acid than native bone without relevant influence on shear force resistance.

Viscous froth model applied to the motion and topological transformations of two-dimensional bubbles in a channel: three-bubble case.

The viscous froth model is used to predict rheological behaviour of a two-dimensional (2D) liquid-foam system. The model incorporates three physical phenomena: the viscous drag force, the pressure difference across foam films and the surface tension acting along them with curvature. In the so-called infinite staircase structure, the system does not undergo topological bubble neighbour-exchange transformations for any imposed driving back pressure. Bubbles then flow out of the channel of transport in the same order in which they entered it. By contrast, in a simple single bubble staircase or so-called lens system, topological transformations do occur for high enough imposed back pressures. The three-bubble case interpolates between the infinite staircase and simple staircase/lens. To determine at which driving pressures and at which velocities topological transformations might occur, and how the bubble areas influence their occurrence, steady-state propagating three-bubble solutions are obtained for a range of bubble sizes and imposed back pressures. As an imposed back pressure increases quasi-statically from equilibrium, complex dynamics are exhibited as the systems undergo either topological transformations, reach saddle-node bifurcation points, or asymptote to a geometrically invariant structure which ceases to change as the back pressure is further increased.

Non-steroidal anti-inflammatory drugs (NSAIDs) associate with zwitterionic phospholipids: insight into the mechanism and reversal of NSAID-induced gastrointestinal injury.

The molecular basis of the injurious actions of non-steroidal anti-inflammatory drugs (NSAIDs) on the gastrointestinal (GI) tract is only partly understood. In this study we have obtained evidence, employing both in vitro and in vivo systems, that five NSAIDs have the ability to form a chemical association with zwitterionic phospholipids. Since this same class of phospholipids line the luminal aspects of the mucus gel layer to provide it with non-wettable properties, this intermolecular association may be the mechanism by which NSAIDs attenuate the hydrophobic barrier properties of the upper GI tract. Preassociating a number of NSAIDs with exogenous zwitterionic phospholipids prevented this increase in surface wettability of the mucus gel layer and protected rats against the injurious GI side-effects of these drugs, while enhancing their lipid permeability, antipyretic and anti-inflammatory activity.

Correlation between proximal serrated polyp detection and clinically significant serrated polyps: inter-endoscopist variability.

INTRODUCTION AND AIMS: The adenoma detection rate (ADR) is the most important quality indicator for the prevention of colorectal cancer but serrated polyps are also precursor lesions of the disease. The aim of our study was to compare the detection rate of proximal serrated polyps (PSPs) and that of clinically significant serrated polyps (CSSPs) between endoscopists and analyze the relation of those parameters to the ADR. METHODS: An observational, prospective, cross-sectional study was conducted on all patients that underwent colonoscopy at the Policlínico Peruano Japonés within the time frame of July 2015 and August 2016. The ADR and PSP and CSSP detection rates between endoscopists were compared through multivariate logistic regression and the association between those parameters was calculated through the Pearson correlation coefficient. RESULTS: The study included 15 endoscopists and 1,378 colonoscopies. The PSP detection rate ranged from 1.8-17% between endoscopists and had an almost perfect correlation with the CSSP detection rate (p = 0.922), as well as strongly correlating with the ADR (p = 0.769). CONCLUSIONS: There was great variability in the PSP detection rate between endoscopists. It also had an almost perfect correlation with the CSSP detection rate and strongly correlated with the ADR. Those results suggest a high CSSP miss rate at endoscopy and a low PSP detection rate.

Influence of antibiotic pellets on pore size and shear stress resistance of impacted native and thermodisinfected cancellous bone: An in vitro femoral impaction bone grafting model.

INTRODUCTION: Morphology and mechanic properties of impacted cancellous bone are affected by carrier substances which provide high local concentrations of antibiotics. METHODS: Bone chips were taken from the femoral head of 6-7 months old piglets. One half was thermodisinfected and the other remained native. Ten specimens each were mixed with Herafill® antibiotic pellets and a control group of each 10 specimens respectively was examined. The cancellous bone was impacted according to Exeter technique and the implants were cemented. The distribution of the particles and the pores were defined with three dimensional computertomographic scan and shear force resistance was measured until failure. RESULTS: Shear force resistance was not measured significantly less for thermodisinfected (2.7 Nm) compared with native bone (3.5 Nm) and addition of antibiotic pellets reduced shear force resistance in both groups since this was significant for the native group. The average pore volume of the native bone specimens appeared significant smaller compared to the thermodisinfected group (p = 0.011) and the pore volume showed a negative correlation with shear force resistance (p = 0.044). Pore volume around the pellets was found significantly increased and it appeared smaller for native bone. The number of pellets located next to the implant showed a negative correlation with shear force resistance (p = 0.034) and the negative correlation increased for pellets below the tip of the shaft model (p = 0.024). CONCLUSION: Adding antibiotic pellets to native and thermodisinfected impacted cancellous bone increased pore volume since the area around the pellets showed increased porosity which correlated with reduced shear force resistance. Computertomographic three dimensional measurement of porosity might predict shear force resistance of impacted cancellous bone and improve impaction of bone grafting intraoperatively.

Clinical evaluation of a novel press-fit acetabular cup using "Ein-Bild-Roentgen-Analysis" (EBRA): A positive short-term prognosis.

INTRODUCTION: Demographic change and demand for high quality of life lead to increasing implantation numbers. Aim of this study was to compare the Plasmafit® cup to Allofit® and Plasmacup®. METHODS: The study included 174 patients who had received 33 Plasmacup®, 68 Allofit® and 73 Plasmafit® cup implants. These were reviewed postoperatively, after 6 months control and after 12 months. RESULTS: No significant progressive migration could be discovered in any of the cup systems. At each follow-up the cups showed nearly constant values. CONCLUSIONS: All examined acetabular cups showed excellent migration behavior within the first 12 postoperative months.

Correlation between proximal serrated polyp detection and clinically significant serrated polyps: inter-endoscopist variability. / Correlación entre la detección de pólipos serratos proximales y pólipos serratos clínicamente significativos: variabilidad interendoscopista.

INTRODUCTION AND AIMS: The adenoma detection rate (ADR) is the most important quality indicator for the prevention of colorectal cancer but serrated polyps are also precursor lesions of the disease. The aim of our study was to compare the detection rate of proximal serrated polyps (PSPs) and that of clinically significant serrated polyps (CSSPs) between endoscopists and analyze the relation of those parameters to the ADR. METHODS: An observational, prospective, cross-sectional study was conducted on all patients that underwent colonoscopy at the Policlínico Peruano Japonés within the time frame of July 2015 and August 2016. The ADR and PSP and CSSP detection rates between endoscopists were compared through multivariate logistic regression and the association between those parameters was calculated through the Pearson correlation coefficient. RESULTS: The study included 15 endoscopists and 1,378 colonoscopies. The PSP detection rate ranged from 1.8-17% between endoscopists and had an almost perfect correlation with the CSSP detection rate (p = 0.922), as well as strongly correlating with the ADR (p = 0.769). CONCLUSIONS: There was great variability in the PSP detection rate between endoscopists. It also had an almost perfect correlation with the CSSP detection rate and strongly correlated with the ADR. Those results suggest a high CSSP miss rate at endoscopy and a low PSP detection rate.

Foam-liquid front motion in Eulerian coordinates.

A mathematical model formulated as a system of Hamilton-Jacobi equations describes implicitly the propagation of a foam-liquid front in an oil reservoir, as the zero-level set of the solution variable. The conceptual model is based on the 'pressure-driven growth' model in Lagrangian coordinates. The Eulerian mathematical model is solved numerically, where the marching is done via a finite volume scheme with an upwind flux. Periodic reinitialization ensures a more accurate implicit representation of the front. The numerical level set contour values are initially formed to coincide with an early time asymptotic analytical solution of the pressure-driven growth model. Via the simulation of the Eulerian numerical model, numerical data are obtained from which graphical representations are generated for the location of the propagating front, the angle that the front normal makes with respect to the horizontal and the front curvature, all of which are compared with the Lagrangian model predictions. By making this comparison, it is possible to confirm the existence of a concavity in the front shape at small times, which physically corresponds to an abrupt reorientation of the front over a limited length scale.

Walking in the shoes of caregivers of children with obesity: supporting caregivers in paediatric weight management.

To incorporate the perspectives and experiences of family caregivers of children with obesity, the KidFit Health and Wellness Clinic, a paediatric weight management programme, embedded feedback opportunities into various stages of programme development. Caregivers were eligible to participate if their children had completed initial 4-week group-based pilot programming or were currently receiving treatment in 10 or 12 week group-based programming. Data were collected through feedback session discussions, audio-recorded, transcribed verbatim and analysed thematically. In total, 6 caregivers participated in the pilot group feedback session and 32 caregivers participated in the structured group feedback sessions. Caregivers reported that healthy lifestyle strategies first communicated by clinic staff to children during group sessions provided expert validation and reinforcement when discussing similar messages at home. Caregivers reported feeling isolated and blamed for causing their children's obesity and appreciated the supportive forum that group-based programming provided for sharing experiences. Since experiences of blame and isolation can burden caregivers of children with obesity, paediatric weight management programmes might consider including peer support opportunities and discussion forums for ongoing social support in addition to education about lifestyle change.

Retiro de medicamentos antineoplásicos en un hospital nacional en Costa Rica / Antineoplastic medication pick-up rates in a Costa Rican national hospital

OBJETIVO: Analizar los porcentajes de dosis retiradas de medicamentos oncológicos no incluidos en la Lista Oficial de Medicamentos según el servicio médico prescriptor y la vía de administración del fármaco, en un hospital de tercer nivel de atención en Costa Rica. Métodología: Los datos fueron obtenidos de manera retrospectiva a partir de bases de datos desarrolladas a nivel hospitalario para el control de los medicamentos adquiridos y a partir de los registros de medicamentos despachados. RESULTADOS: Las unidades aprobadas para compra en los Servicios de Oncología y Hematología no son retiradas en su totalidad por los pacientes en tratamiento oncológico. En general, el porcentaje de retiro fue de 90,3% para 98 solicitudes de compra. Existen diferencias estadísticamente significativas en los porcentajes de retiro según el servicio médico prescriptor ( t= -2,68; p = 0,01) y la vía de administración de los medicamentos (t = -2,61; p = 0,01). Del análisis multivariado se desprende que en el Servicio de Oncología Médica el porcentaje de retiro de medicamentos es significativamente menor entre las personas divorciadas (beta = -4,7; p < 0,01) y viudas (beta = -20,5; p = 0,01) en comparación con las personas casadas. CONCLUSIONES: El retiro de medicamentos, si bien no es una forma de medir la adherencia terapéutica, permite establecer una relación primaria entre el paciente y el tratamiento a administrar. El subretiro de medicamentos encontrado mediante este estudio evidencia la necesidad de ampliar la investigación con el fin de conocer los motivos por los que los pacientes no retiran sus tratamientos oncológicos de compra

OBJECTIVE: To analyze the percentage of picked-up doses of oncologic drugs not included in the Essential Medicine List according to the medical prescribing service and the administration route of the drug in a third level hospital in Costa Rica. METHOD: Data was obtained by retrospective analysis from databases developed for the hospital's control of acquired drugs and from the dispatched drug registry. RESULTS: Not all medications acquired through the special drug buying mechanism are picked-up by patients from the Oncology and Hematology Services. Overall, the pick-up rate was 90.3% for the 98 processes analyzed. Significant differences for the picking-up percentages were found for the medical prescribing service (t = -2.68; p = 0.01) and the drug's administration route (t = -2.61; p = 0.01). Multivariate analysis shows that for the Medical Oncology Service, pick-up rate is significantly lower among divorced (Beta = -4.7; p < 0.01) and widowed (Beta = -20.5; p = 0.01) patients compared to married ones. CONCLUSIONS: Even when pick-up rates are not a way to measure therapeutic adherence, they allow to establish a primary relationship between the patient and its treatment. The underpicking of treatments found by this study shows the need to increase the research in order to understand patient's reasons to abandon oncologic treatments that are not included in the Essential Medicine List

[Campylobacter pyloric, chronic gastritis, gastric ulcer and duodenal ulcer]. / Campylobacter pilórico, gastritis crónica, úlcera gástrica y úlcera duodenal.

After the initial report of Marshall and Warren, several publications have also demonstrated the presence of pyloric campylobacter in an elevated percentage of cases of chronic gastritis and peptic ulcer. We present our experience studying 672 patients examined by esophagogastroduodenoscopy after referral to clinical because of upper gastrointestinal symptoms. We used an Olympus GIF-K2 panendoscope taking two biopsies from the gastric antrum. Specimens were stained with hematoxilin-eosin and silver. In our experience these methods have given us the best results in detecting this bacteria. Diagnosis of gastric and duodenal ulcer was made by endoscopic criteria and chronic gastritis diagnosed by histology. Chronic gastritis was categorized into active and inactive based in the invasion of polymorphonuclear into mucosa. We have also quantitated damage of the mucin producing cells as well as the degree of bacterial colonization. We have found pyloric campylobacter in 91.8% of patients suffering from chronic active gastritis, 72.7% of patients with diagnosis of gastric ulcer and 84.2% of cases of duodenal ulcer. Our results agree with the ones reported by other authors. We conclude that pyloric campylobacter is not an opportunist microorganism within the stomach because it produces inflammatory changes as well as damage of the mucin producing cells. Its presence may play some role in the etiology of gastritis and peptic ulcer disease.

[Detection of pyloric Campylobacter in patients with gastroduodenal diseases]. / Detección del Campylobacter pilórico en pacientes con enfermedades gastroduodenales.

We report a study of 127 patients examined with esophago-gastroduodenoscopy and with a diagnosis of chronic gastritis (by biopsy), and gastric peptic ulcer and duodenal peptic ulcer (endoscopically). Brushing samples and biopsies were taken from the esophagus, stomach, and duodenum. Gram stains of brush-collected samples, culture of brush samples and biopsies were performed in order to detect the presence of PC. In cases of chronic active gastritis, PC was found in 91% of patients. It was found in 73% and 84%, respectively, of cases of gastric and duodenal ulcer. PC was found with equal frequency in the cardia and body as in the antrum of infected individuals, but no confirmed cases of colonization of the esophagus or duodenum were found. The most efficient methods for identifying PC colonization were (in descending order of efficiency), silver stain of biopsies, Gram stain of brushings, hematoxylin-eosin stain of biopsies, culture of biopsies, and culture of brushings. In some cases, we have identified PC in the esophagus and duodenum by gram stain and culture, but no not by silver stain or H&E stain of biopsies, suggesting that contamination from other areas of the stomach may be an occasional problem in sampling these areas for PC.

[Campylobacter pyloridis and socioeconomic levels]. / Campylobacter pilórico y nivel socio-económico.

The purpose of this study was to determine if there was any relationship between the socio-economic level of patients and the colonization of the stomach by Campylobacter pyloridis. We have studied 256 patients who underwent esophagogastroduodenoscopy because they had upper gastrointestinal symptoms of this group, 143 from Arzobispo Loayza Hospital (38 males and 105 females) and 122 from the private practice of three of the authors (77 males and 45 females). The ages ranged from 16 to 75 years (media 45.5 years). In each case biopsies of the antrum were taken and stained with hematoxylin-eosin and Warthin-Starry Silver Stein. We classified patients into 3 different groups based on where they lived: nuclear districts, intermediate districts, and peripheral districts. In Lima, the type of district from the patient strongly correlates with their socio-economic status. The hospital and private patients differed significantly in the distribution of which type of district their patients came from. In contrast there was a no marked similarity between these two patient groups in their rate of colonization by Campylobacter pyloridis. It appears that the socio-economic level of peruvian patients, presenting to clinic with symptomatic gastro-intestinal disease is not an important factor with pyloric campylobacter infection.

Gastric emptying rates in idiopathic dyspepsia with and without "hunger pain".

It has been previously observed that in dyspeptic patients with "hunger pain", that is, with pain suggestive of the presence of peptic ulcer, only 12% had an endoscopically demonstrated ulcer, the remaining 88% showing absence of important macroscopically detectable lesions (idiopathic dyspepsia). In order to investigate the possibility of a relationship between "hunger pain" and some alteration in gastroduodenal motility, the gastric emptying rates of patients presenting idiopathic dyspepsia with and without "hunger pain" were compared with those of normal control subjects. The study was conducted in 40 patients presenting idiopathic dyspepsia, 20 with and 20 without "hunger pain", and 30 voluntary apparently normal control subjects. The patients and the controls ingested, with a standard breakfast, a gelatine capsule containing 10 radioopaque polyurethane markers, and the gastric emptying of the markers was evaluated taking 3 x-ray films of the abdomen at 1.5, 3.0 and 4.5 hours after the breakfast. The gastric emptying rates of the markers were significantly higher in the patients with "hunger pain", and significantly lower in the patients without "hunger pain", than in the normal control subjects. In idiopathic dyspepsia with and without "hunger pain" there are, respectively, abnormally increased and abnormally decreased gastric emptying rates of undigestible solid markers. Our findings could help to better understand the pathogenesis of those different types of dyspepsia and, consequently, to improve their treatment.

[Various characteristics of Helicobacter pylori infection in Perú]. / Algunas características de la infección por Helicobacter pylori en el Perú.

The rate of infection by Helicobacter pylori in peruvian dyspeptic patients (84%) is higher than that reported in symptomatic patients from developed countries. Helicobacter pylori infection did not increase with age. The ecological distribution is similar in the three different geographical regions of Peru. Only women of high economic status had significantly lower rates of Helicobacter pylori infection compared to all other groups. The recurrence rate after treatment is higher than that reported from developed countries.