Effect of two different bioabsorbable collagen membranes on guided bone regeneration: a comparative histomorphometric study in the dog mandible

BACKGROUND: This study compared bone regeneration following guided bone regeneration with two bioabsorbable collagen membranes in saddle-type bone defects in dog mandibles. METHODS: Three standardized defects were created, filled with bone chips and deproteinized bovine bone mineral (DBBM), and covered by three different methods: control = no membrane; test 1 = collagen membrane; and test 2 = cross-linked collagen membrane (CCM). Each side of the mandible was allocated to one of two healing periods (8 or 16 weeks). The histomorphometric analysis assessed the percentage of bone, soft tissue, and DBBM in the regenerate; the absolute area in square millimeters of the bone regenerate; and the distance in millimeters from the bottom of the defect to the highest point of the regenerate. RESULTS: In the 8-week healing group, two dehiscences occurred with CCM. After 8 weeks, all treatment modalities showed no significant differences in the percentage of bone regenerate. After 16 weeks, the percentage of bone had increased for all treatment modalities without significant differences. For all groups, the defect fill height increased between weeks 8 and 16. The CCM group showed a statistically significant (P = 0.0202) increase over time and the highest value of all treatment modalities after 16 weeks of healing, CONCLUSIONS: The CCM showed a limited beneficial effect on bone regeneration in membrane-protected defects in dog mandibles when healing was uneventful. The observed premature membrane exposures resulted in severely compromised amounts of bone regenerate. This increased complication rate with CCM requires a more detailed preclinical and clinical examination before any clinical recommendations can be made.

Effect of two bioabsorbable barrier membranes on bone regeneration of standardized defects in calvarial bone: a comparative histomorphometric study in pigs

BACKGROUND: The effect of two different bioabsorbable collagen membranes on bone regeneration was assessed in standardized, membrane-protected calvarial defects in pigs. METHODS: Two standardized defect types (6 x 6 x 6 mm and 9 x 9 x 9 mm) were produced in the calvaria of pigs: empty defects without a membrane (group 1; eight defects per size); defects filled with deproteinized bovine bone mineral (DBBM) without a membrane (group 2; eight defects per size); defects filled with DBBM and covered by a collagen membrane (group 3; eight defects per size); and defects filled with DBBM and covered by a cross-linked collagen membrane (CCM) (group 4; eight defects per size). Sacrifice took place 16 weeks after surgery, and the following parameters were analyzed: descriptive histology; semiquantitative histology (SQH), assessing bone regeneration in the whole defect area; and histomorphometric analysis of the percentage of bone and DBBM in the regenerated area at three different depth levels of the defect. RESULTS: Using SQH, both membrane types resulted in significantly better bone regeneration compared to groups 1 and 2, irrespective of the defect size (P <0.005), with no difference between the two membranes. In the histomorphometric analysis, the layer immediately below the surface exhibited a significantly higher percentage of bone in groups 3 (27%) and 4 (36%) versus the two other groups for the 9 x 9 x 9-mm defects. No such differences were apparent for the 6 x 6 x 6-mm defects or the other two depth levels (bottom and middle layer) for either defect size. CONCLUSIONS: The two collagen membranes tested significantly enhanced bone regeneration, especially in the superficial level of the calvarial bone defects. The prototype CCM did not provide any further advantage in the present animal model.

A retrospective comparative exploratory study on two methylentetrahydrofolate reductase (MTHFR) polymorphisms in esophagogastric cancer: the A1298C MTHFR polymorphism is an independent prognostic factor only in neoadjuvantly treated gastric cancer patients.

BACKGROUND Methylentetrahydrofolate reductase (MTHFR) plays a major role in folate metabolism and consequently could be an important factor for the efficacy of a treatment with 5-fluorouracil. Our aim was to evaluate the prognostic and predictive value of two well characterized constitutional MTHFR gene polymorphisms for primarily resected and neoadjuvantly treated esophagogastric adenocarcinomas. METHODS 569 patients from two centers were analyzed (gastric cancer: 218, carcinoma of the esophagogastric junction (AEG II, III): 208 and esophagus (AEG I): 143). 369 patients received neoadjuvant chemotherapy followed by surgery, 200 patients were resected without preoperative treatment. The MTHFR C677T and A1298C polymorphisms were determined in DNA from peripheral blood lymphozytes. Associations with prognosis, response and clinicopathological factors were analyzed retrospectively within a prospective database (chi-square, log-rank, cox regression). RESULTS Only the MTHFR A1298C polymorphisms had prognostic relevance in neoadjuvantly treated patients but it was not a predictor for response to neoadjuvant chemotherapy. The AC genotype of the MTHFR A1298C polymorphisms was significantly associated with worse outcome (p = 0.02, HR 1.47 (1.06-2.04). If neoadjuvantly treated patients were analyzed based on their tumor localization, the AC genotype of the MTHFR A1298C polymorphisms was a significant negative prognostic factor in patients with gastric cancer according to UICC 6th edition (gastric cancer including AEG type II, III: HR 2.0, 95% CI 1.3-2.0, p = 0.001) and 7th edition (gastric cancer without AEG II, III: HR 2.8, 95% CI 1.5-5.7, p = 0.003), not for AEG I. For both definitions of gastric cancer the AC genotype was confirmed as an independent negative prognostic factor in cox regression analysis. In primarily resected patients neither the MTHFR A1298C nor the MTHFR C677T polymorphisms had prognostic impact. CONCLUSIONS The MTHFR A1298C polymorphisms was an independent prognostic factor in patients with neoadjuvantly treated gastric adenocarcinomas (according to both UICC 6th or 7th definitions for gastric cancer) but not in AEG I nor in primarily resected patients, which confirms the impact of this enzyme on chemotherapy associated outcome.

Diagnostic endoscopy of the navicular bursa using a needle endoscope by direct or transthecal approach: A comparative cadaver study

OBJECTIVES: To compare the practicability, visualization of structures, and iatrogenic damage of direct and transthecal approaches to the navicular bursa for diagnostic needle endoscopy. STUDY DESIGN: Descriptive study. SAMPLE POPULATION: Equine cadaver forelimbs (n = 30). METHODS: Direct and transthecal approaches for insertion of a needle endoscope into the navicular bursa were performed. Video recordings of endoscopic procedures were assessed to determine all structures visualized within the navicular bursa. Number of attempts to gain access to the navicular bursa and total time for insertion and examination were recorded. Distribution and severity of iatrogenic lesions were assessed and scored after dissection. RESULTS: There were no statistical differences for number of attempts or time needed for insertion and examination between direct and transthecal approaches. The direct approach offered significantly increased visibility of the ipsilateral abaxial and proximal margins of the navicular bone, and ipsilateral collateral sesamoidean ligament. Iatrogenic lesions were superficial and focal, regardless of approach taken, or whether a blunt or sharp trocar tip was used. CONCLUSIONS: The direct approach provided significantly better visualization of the ipsilateral structures within the navicular bursa compared to the transthecal approach. Needle endoscopy offers a reliable technique to evaluate the navicular bursa and may complement or replace other diagnostic modalities in horses with lameness localized to the navicular region.

Comparative Cytotoxicity Study of Silver Nanoparticles (AgNPs) in a Variety of Rainbow Trout Cell Lines (RTL-W1, RTH-149, RTG-2) and Primary Hepatocytes.

Among all classes of nanomaterials, silver nanoparticles (AgNPs) have potentially an important ecotoxicological impact, especially in freshwater environments. Fish are particularly susceptible to the toxic effects of silver ions and, with knowledge gaps regarding the contribution of dissolution and unique particle effects to AgNP toxicity, they represent a group of vulnerable organisms. Using cell lines (RTL-W1, RTH-149, RTG-2) and primary hepatocytes of rainbow trout (Oncorhynchus mykiss) as in vitro test systems, we assessed the cytotoxicity of the representative AgNP, NM-300K, and AgNO3 as an Ag+ ion source. Lack of AgNP interference with the cytotoxicity assays (AlamarBlue, CFDA-AM, NRU assay) and their simultaneous application point to the compatibility and usefulness of such a battery of assays. The RTH-149 and RTL-W1 liver cell lines exhibited similar sensitivity as primary hepatocytes towards AgNP toxicity. Leibovitz's L-15 culture medium composition (high amino acid content) had an important influence on the behaviour and toxicity of AgNPs towards the RTL-W1 cell line. The obtained results demonstrate that, with careful consideration, such an in vitro approach can provide valuable toxicological data to be used in an integrated testing strategy for NM-300K risk assessment.

Historical review of Haller's cells

Albrecht von Haller (1708-1777) discovered the infraorbital ethmoid cells, also known as Haller's cells, in 1743. The aim of this historical study is to trace both the different terminology used to name them from the time they were first described anatomically, and the progressive understanding of the role they play in the development of acute rhinosinusitis, and finally to suggest a clear modern definition of Haller's cells based on this history.

Neer Award 2007: Reversion of structural muscle changes caused by chronic rotator cuff tears using continuous musculotendinous traction. An experimental study in sheep

HYPOTHESIS: Chronic rotator cuff tears are associated with irreversible architectural muscle changes and a high rate of repair failure. The changes observed in man and their irreversibility with a single stage repair can be reproduced in sheep. It was the purpose of this experiment to test the hypothesis that slow, continuous elongation of a retracted musculotendinous unit allows reversal of the currently irreversible structural muscle changes. MATERIALS AND METHODS: The infraspinatus tendon of 12 sheep was released using a greater tuberosity osteotomy and allowed to retract for 4 months. Then, a new device was mounted on the scapular spine and used to extend the infraspinatus muscuculotendinous unit transcutaneously by 1 mm per day. Thereafter, the tendon was repaired back to the greater tuberosity. We assessed the muscular architecture using magnetic resonance imaging, macroscopic dissection, histology, and electron microscopy. Fatty infiltration (in Hounsfield units 1/4 HU) and muscular cross-sectional area (in % of the control side) were monitored with computed tomography at tendon release, initiation of elongation, repair, and at sacrifice. RESULTS: Sixteen weeks after tendon release, the mean tendon retraction was 29 +/- 6 mm (14% of original length, P = .008). In 8 sheep, elongation was achieved as planned (group I), but in 4, the elongation failed technically (group II). The mean traction time was 24 +/- 6 days with a mean traction distance of 19 +/- 4 mm. At sacrifice, the mean pennation angle in the infraspinatus of group I was not different from the control side (29.8 degrees +/-7.5 degrees vs. 30 degrees +/-6 degrees , P = .575). In group II, the pennation angle had increased from 30 degrees +/-6 degrees to 55 degrees +/-14 degrees (P = .035). There was no fatty infiltration at the time of tendon release. After retraction, there was a significant increase in fatty infiltration of the infraspinatus muscle and a decrease of its cross-sectional area to 57% of the contralateral side (P = .0001). During traction, the degree of fatty infiltration remained unchanged (36 HU to 38 HU, P = .381), and atrophy improved to a muscle square area of 78% of the contralateral side (P = .0001) in group I. In group II, an increase of fatty infiltration was measured from 36 HU to 28 HU; however, this increase was not significant (P = .144). Atrophy did not change in group II (57-55%, P = .946). At sacrifice, the remaining muscle mass was 64% in group I and 46% in group II (P = .019). DISCUSSION: Our preliminary results document, that continuous elongation of a retracted, fatty infiltrated and atrophied musculotendinous unit is technically feasible. CONCLUSION: In the sheep, continuous elongation can lead to restoration of normal muscle architecture, to partial reversal of muscle atrophy, and to arrest of the progression of fatty infiltration. LEVEL OF EVIDENCE: Basic science level 2; Prospective comparative therapeutic study.

A Comparative Analysis of Beaconless Opportunistic Routing Protocols for Video Dissemination over Flying Ad-Hoc Networks

A reliable and robust routing service for Flying Ad-Hoc Networks (FANETs) must be able to adapt to topology changes, and also to recover the quality level of the delivered multiple video flows under dynamic network topologies. The user experience on watching live videos must also be satisfactory even in scenarios with network congestion, buffer overflow, and packet loss ratio, as experienced in many FANET multimedia applications. In this paper, we perform a comparative simulation study to assess the robustness, reliability, and quality level of videos transmitted via well-known beaconless opportunistic routing protocols. Simulation results shows that our developed protocol XLinGO achieves multimedia dissemination with Quality of Experience (QoE) support and robustness in a multi-hop, multi-flow, and mobile networks, as required in many multimedia FANET scenarios.

Comparative theoretical analysis of continuous wave laser cutting of metals at 1 and 10 um wavelength

We present a derivation and, based on it, an extension of a model originally proposed by V.G. Niziev to describe continuous wave laser cutting of metals. Starting from a local energy balance and by incorporating heat removal through heat conduction to the bulk material, we find a differential equation for the cutting profile. This equation is solved numerically and yields, besides the cutting profiles, the maximum cutting speed, the absorptivity profiles, and other relevant quantities. Our main goal is to demonstrate the model’s capability to explain some of the experimentally observed differences between laser cutting at around 1 and 10 μm wavelengths. To compare our numerical results to experimental observations, we perform simulations for exactly the same material and laser beam parameters as those used in a recent comparative experimental study. Generally, we find good agreement between theoretical and experimental results and show that the main differences between laser cutting with 1- and 10-μm beams arise from the different absorptivity profiles and absorbed intensities. Especially the latter suggests that the energy transfer, and thus the laser cutting process, is more efficient in the case of laser cutting with 1-μm beams.

Impact Assessment: Organic Cotton in Jalalabad, Oblast, Kyrgyztan

The aim of the study was to examine the economic performance as well as perceived social and environmental impacts of organic cotton in Southern Kyrgyzstan on the basis of a comparative field study (44 certified organic farmers and 33 conventional farmers) carried out in 2009. It also investigated farmers’ motivation for and assessment of conversion to organic farming. Cotton yields on organic farms were found to be 10% lower whereby input costs per unit were 42% lower, which resulted in organic farmers having a 20% higher revenue from cotton. Due to lower input costs and organic and fair trade price premiums the average gross margin from organic cotton was 27%. In addition to direct economic benefits organic farmers enjoy a number of additional benefits such as easy access to credits on favourable terms, provision with uncontaminated cotton cooking oil and seed cake as animal feed, marketing support as well as extension and training, services provided by the newly established organic service provider. A big majority of organic farmers perceives an improvement of soil qualities, improved health conditions, and positively assesses their previous decision to convert to organic farming. The major disadvantage of organic farming is the high manual labour input required. In the study area, where manual farm work is mainly women’s work and male labour migration widespread, women are most affected by this negative aspect of organic farming. Altogether, the results suggest that despite the inconvenience of higher work load the advantages of organic farming outweigh the disadvantages and that conversion to organic farming can improve the livelihoods of small-scale farmers.

Potential and limitations of organic and fair trade cotton for improving livelihoods of smallholders: evidence from Central Asia

Cotton is a leading agricultural non-food commodity associated with soil degradation, water pollution and pesticide poisoning due to high levels of agrochemical inputs. Organic farming is often promoted as a means of addressing the economic, environmental and health risks of conventional cotton production, and it is slowly gaining ground in the global cotton market. Organic and fair trade cotton are widely seen as opportunities for smallholder farmers to improve their livelihoods thanks to higher returns, lower input costs and fewer risks. Despite an increasing number of studies comparing the profitability of organic and non-organic farming systems in developing and industrialized countries, little has been published on organic farming in Central Asia. The aim of this article is to describe the economic performance and perceived social and environmental impacts of organic cotton in southern Kyrgyzstan, drawing on a comparative field study conducted by the author in 2009. In addition to economic and environmental aspects, the study investigated farmers’ motivations toward and assessment of conversion to organic farming. Cotton yields on organic farms were found to be 10% lower, while input costs per unit were 42% lower; as a result, organic farmers’ cotton revenues were 20% higher. Due to lower input costs as well as organic and fair trade price premiums, the average gross margin from organic cotton was 27% higher. In addition to direct economic benefits, organic farmers enjoy other benefits, such as easy access to credit on favorable terms, provision of uncontaminated cottonseed cooking oil and cottonseed cake as animal feed, and marketing support as well as extension and training services provided by newly established organic service providers. The majority of organic farmers perceive improved soil quality, improved health conditions, and positively assess their initial decision to convert to organic farming. The major disadvantage of organic farming is the high manual labor input required. In the study area, where manual farm work is mainly women's work and male labor migration is widespread, women are most affected by this negative aspect of organic farming. Altogether, the results suggest that, despite the inconvenience of a higher workload, the advantages of organic farming outweigh its disadvantages and that conversion to organic farming improves the livelihoods of small-scale farmers.

Somatostatin-based radiopeptide therapy with [177Lu-DOTA]-TOC versus [90Y-DOTA]-TOC in neuroendocrine tumours

PURPOSE Somatostatin-based radiopeptide treatment is generally performed using the β-emitting radionuclides (90)Y or (177)Lu. The present study aimed at comparing benefits and harms of both therapeutic approaches. METHODS In a comparative cohort study, patients with advanced neuroendocrine tumours underwent repeated cycles of [(90)Y-DOTA]-TOC or [(177)Lu-DOTA]-TOC until progression of disease or permanent adverse events. Multivariable Cox regression and competing risks regression were employed to examine predictors of survival and adverse events for both treatment groups. RESULTS Overall, 910 patients underwent 1,804 cycles of [(90)Y-DOTA]-TOC and 141 patients underwent 259 cycles of [(177)Lu-DOTA]-TOC. The median survival after [(177)Lu-DOTA]-TOC and after [(90)Y-DOTA]-TOC was comparable (45.5 months versus 35.9 months, hazard ratio 0.91, 95% confidence interval 0.63-1.30, p = 0.49). Subgroup analyses revealed a significantly longer survival for [(177)Lu-DOTA]-TOC over [(90)Y-DOTA]-TOC in patients with low tumour uptake, solitary lesions and extra-hepatic lesions. The rate of severe transient haematotoxicities was lower after [(177)Lu-DOTA]-TOC treatment (1.4 vs 10.1%, p = 0.001), while the rate of severe permanent renal toxicities was similar in both treatment groups (9.2 vs 7.8%, p = 0.32). CONCLUSION The present results revealed no difference in median overall survival after [(177)Lu-DOTA]-TOC and [(90)Y-DOTA]-TOC. Furthermore, [(177)Lu-DOTA]-TOC was less haematotoxic than [(90)Y-DOTA]-TOC.

Explaining Emergence and Consequences of Specific Formal Controls in IS Outsourcing – A Process-View

IS outsourcing projects often fail to achieve project goals. To inhibit this failure, managers need to design formal controls that are tailored to the specific contextual demands. However, the dynamic and uncertain nature of IS outsourcing projects makes the design of such specific formal controls at the outset of a project challenging. Hence, the process of translating high-level project goals into specific formal controls becomes crucial for success or failure of IS outsourcing projects. Based on a comparative case study of four IS outsourcing projects, our study enhances current understanding of such translation processes and their consequences by developing a process model that explains the success or failure to achieve high-level project goals as an outcome of two unique translation patterns. This novel process-based explanation for how and why IS outsourcing projects succeed or fail has important implications for control theory and IS project escalation literature.

The Emergence of Formal Control Specificity in Information Systems Outsourcing: A Process-View

Information systems (IS) outsourcing projects often fail to achieve initial goals. To avoid project failure, managers need to design formal controls that meet the specific contextual demands of the project. However, the dynamic and uncertain nature of IS outsourcing projects makes it difficult to design such specific formal controls at the outset of a project. It is hence crucial to translate high-level project goals into specific formal controls during the course of a project. This study seeks to understand the underlying patterns of such translation processes. Based on a comparative case study of four outsourced software development projects, we inductively develop a process model that consists of three unique patterns. The process model shows that the performance implications of emergent controls with higher specificity depend on differences in the translation process. Specific formal controls have positive implications for goal achievement if only the stakeholder context is adapted, while they are negative for goal achievement if in the translation process tasks are unintendedly adapted. In the latter case projects incrementally drift away from their initial direction. Our findings help to better understand control dynamics in IS outsourcing projects. We contribute to a process theoretic understanding of IS outsourcing governance and we derive implications for control theory and the IS project escalation literature.

Prevention of increased abnormal fundus autofluorescence with blue light-filtering intraocular lenses

PURPOSE To observe changes in fundus autofluorescence 2 years after implantation of blue light-filtering (yellow-tinted) and ultraviolet light-filtering (colorless) intraocular lenses (IOLs). SETTING Department of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan, and the Department of Ophthalmology, University of Bern, Bern, Switzerland. DESIGN Prospective comparative observational study. METHODS Patients were enrolled who had cataract surgery with implantation of a yellow-tinted or colorless IOL and for whom images were obtained on which the fundus autofluorescence was measurable using the Heidelberg Retina Angiogram 2 postoperatively. The fundus autofluorescence in the images was classified into 8 abnormal patterns based on the classification of the International Fundus Autofluorescence Classification Group, The presence of normal fundus autofluorescence, geographic atrophy, and wet age-related macular degeneration (AMD) also was recorded. The fundus findings at baseline and 2 years postoperatively were compared. RESULTS Fifty-two eyes with a yellow-tinted IOL and 79 eyes with a colorless IOL were included. Abnormal fundus autofluorescence did not develop or increase in the yellow-tinted IOL group; however, progressive abnormal fundus autofluorescence developed or increased in 12 eyes (15.2%) in the colorless IOL group (P = .0016). New drusen, geographic atrophy, and choroidal neovascularization were observed mainly in the colorless IOL group. The incidence of AMD was statistically significantly higher in the colorless IOL group (P = .042). CONCLUSIONS Two years after cataract surgery, significant differences were seen in the progression of abnormal fundus autofluorescence between the 2 groups. The incidence of AMD was lower in eyes with a yellow-tinted IOL. FINANCIAL DISCLOSURE No author has a financial or proprietary interest in any material or method mentioned.