Ensuring privacy protection in the era of big laparoscopic video data: development and validation of an inside outside discrimination algorithm (IODA)

BACKGROUND

Laparoscopic videos are increasingly being used for surgical artificial intelligence (AI) and big data analysis. The purpose of this study was to ensure data privacy in video recordings of laparoscopic surgery by censoring extraabdominal parts. An inside-outside-discrimination algorithm (IODA) was developed to ensure privacy protection while maximizing the remaining video data.

METHODS

IODAs neural network architecture was based on a pretrained AlexNet augmented with a long-short-term-memory. The data set for algorithm training and testing contained a total of 100 laparoscopic surgery videos of 23 different operations with a total video length of 207 h (124 min ± 100 min per video) resulting in 18,507,217 frames (185,965 ± 149,718 frames per video). Each video frame was tagged either as abdominal cavity, trocar, operation site, outside for cleaning, or translucent trocar. For algorithm testing, a stratified fivefold cross-validation was used.

RESULTS

The distribution of annotated classes were abdominal cavity 81.39%, trocar 1.39%, outside operation site 16.07%, outside for cleaning 1.08%, and translucent trocar 0.07%. Algorithm training on binary or all five classes showed similar excellent results for classifying outside frames with a mean F1-score of 0.96 ± 0.01 and 0.97 ± 0.01, sensitivity of 0.97 ± 0.02 and 0.0.97 ± 0.01, and a false positive rate of 0.99 ± 0.01 and 0.99 ± 0.01, respectively.

CONCLUSION

IODA is able to discriminate between inside and outside with a high certainty. In particular, only a few outside frames are misclassified as inside and therefore at risk for privacy breach. The anonymized videos can be used for multi-centric development of surgical AI, quality management or educational purposes. In contrast to expensive commercial solutions, IODA is made open source and can be improved by the scientific community.

VEGF beta is a candidate biomarker for cardiovascular risk stratification

Background

The blood-based transcriptome changes in relation to body weight but longitudinal data on specific transcripts are rare. Monocytes play a crucial role in the development of atherosclerosis and coronary artery disease. Monitoring monocytic gene expression patterns could aid to identify biomarkers for improved cardiovascular risk stratification. BMI and diabetes mellitus (T2DM) are associated with coronary artery disease (CAD). There are mRNAs associated with the development of atherosclerosis and CAD, which can be detected in circulating cells. The exact pathways and direct targets have not been explored.

Objective

To apply transcriptome screening and validation analysis to identify novel biomarker candidates associated with longitudinal changes of BMI as cardiovascular risk factors and test association with clinical endpoints.

Methods

Transcriptome-wide monocytic gene expression changes were screened in relation to changes in BMI over a time period of 5 years in 1,092 participants of the Gutenberg Health Study with available transcriptomics data at baseline investigation and at 5-years follow-up. Functional enrichment of BMI-related genes (FDR <0.01) was tested based on pathway databases and selected gene sets. Serum VEGFB levels were quantified and validated in serum from n=1,895 individuals from an independent cohort study (FinRisk). In-vitro, THP1 cells were stimulated with recombinant VEGFB.

Results

143 transcripts showed a significant association with change in BMI over 5 years. Decreased VEGFB mRNA levels strongly associated with increased BMI (p=2.8x10–9). Lower levels of VEGFB mRNA were associated with increased mortality (HRperSD=0.757, 95% CI: 0.647–0.885, p=0.0005) following adjustment for age and sex and incident diabetes (p=0.01). Circulating VEGFB levels inversely correlated with VEGFB mRNA (r=−0.2, p=0.0024) and positively correlated with an increase in BMI (beta=0.226, p=8.4x10–6), type 2 diabetes mellitus risk (HRperSD=1.279, 95% CI: 1.148–1.425, p=7.8x10–6) and all-cause mortality (HRperSD=1.184, 95% CI: 1.045–1.342, p=0.008). Further exploration in n=1,895 individuals from FinRisk revealed an association of increased VEGFB levels with increased risk for heart failure (HRperSD=1.373, 95% CI: 1.210–1.560, p=1.0x10–6) and coronary artery disease (HR=1.018, 95% CI: 1.003–1.034, p=0.019), even after adjustment for BMI. In THP-1 culture, stimulation with VEGFB resulted in downregulation of VEGFB mRNA levels.

Conclusion

Decreased monocytic gene expression of VEGFB is related to increased BMI, increased risk of T2DM and all-cause mortality. Vice versa,circulating VEGFB levels associates positively with BMI, diabetes, mortality as well as heart failure and coronary heart disease. We hypothesize that monocytes regulate VEGFB expression by a negative feed-back mechanism based. Circulating VEGFB is a potential novel biomarker candidate for weight-related diabetes risk and cardiovascular risk evaluation.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): DZHK

MiR-205-driven downregulation of cholesterol biosynthesis through SQLE-inhibition identifies therapeutic vulnerability in aggressive prostate cancer

Prostate cancer (PCa) shows strong dependence on the androgen receptor (AR) pathway. Here, we show that squalene epoxidase (SQLE), an enzyme of the cholesterol biosynthesis pathway, is overexpressed in advanced PCa and its expression correlates with poor survival. SQLE expression is controlled by micro-RNA 205 (miR-205), which is significantly downregulated in advanced PCa. Restoration of miR-205 expression or competitive inhibition of SQLE led to inhibition of de novo cholesterol biosynthesis. Furthermore, SQLE was essential for proliferation of AR-positive PCa cell lines, including abiraterone or enzalutamide resistant derivatives, and blocked transactivation of the AR pathway. Inhibition of SQLE with the FDA approved antifungal drug terbinafine also efficiently blocked orthotopic tumour growth in mice. Finally, terbinafine reduced levels of prostate specific antigen (PSA) in three out of four late-stage PCa patients. These results highlight SQLE as a therapeutic target for the treatment of advanced PCa.

[Apophyseal avulsion in the pelvic region in childhood and adolescence]

BACKGROUND

The importance of the apophyseal plates during growth is often underestimated. They act as a muscular insertion and influence the joint mechanics by the load-dependent change in shape.

PATHOMECHANISMS

An anatomically functional adaptation occurs as protection from overloading. In special kinds of sports with highly dynamic movements, sudden changes of direction and eccentric/concentric muscle activities the resulting stress may exceed the strength of the apophyseal plate. In adolescence this results in a total or partial tearing of the apophysis in the sense of an avulsion injury. In the pelvic region the ischial tuberosity, the anterior superior and inferior iliac spine are mainly affected.

DIAGNOSTICS

The medical history and clinical diagnostics are supplemented by conventional radiographic imaging. Sectional imaging diagnostics are usually unnecessary.

TREATMENT

Conservative management by reduced (partial) weight bearing and physiotherapy represents the gold standard in treatment. In cases with a fragment displacement >1.5-2.0 cm and in competitive athletes an open reduction should be considered.

Biallelic CSGALNACT1-mutations cause a mild skeletal dysplasia

Genetic causes of skeletal disorders are manifold and affect, among others, enzymes of bone and connective tissue synthesis pathways. We present a twelve-year-old boy with a mild skeletal dysplasia, hypermobility of joints and axial malalignment of lower limbs and feet. Exome sequencing revealed a biallelic loss of function mutation in CSGALNACT1, which encodes chondroitin sulfate N-acetylgalactosaminyltransferase 1 and plays a major role in the chondroitin sulfate chain biosynthesis and therefore in the synthesis of glycosaminoglycans. Recently, the first case of a pediatric patient with a mild skeletal dysplasia due to a compound heterozygous large intragenic deletion and a damaging missense variant in CSGALNACT1 was reported. We here identify a second case and the first juvenile patient with a homozygous frameshift variant in CSGALNACT1 which corroborates its role in mild and non-progressive skeletal dysplasia with joint laxity.

Association of CCL2 with systemic inflammation in Schnitzler syndrome

BACKGROUND

Schnitzler syndrome (SchS) is a rare autoinflammatory disease characterized by urticarial exanthema, bone and joint alterations, fever and monoclonal gammopathy, which manifest mostly in the second half of life. It involves overactivation of the interleukin (IL)-1 system, but the exact pathophysiological pathways remain largely unknown.

OBJECTIVES

To identify and characterize the pathogenetic players in SchS.

METHODS

Blood parameters were quantified in patients with SchS compared with healthy controls and patients with psoriasis and hidradenitis suppurativa using enzyme-linked immunosorbent assay (ELISA). CCL2 expression in cultured primary cells was analysed by quantitative reverse-transcriptase polymerase chain reaction and ELISA.

RESULTS

CCL2, a chemoattractant for monocytic and further mononuclear immune cells, was found to be significantly elevated in patients with SchS. CCL2 levels showed a positive association with global disease activity, especially with bone pain, but not disease duration, gammopathy, neutrophilia or skin disease. In vitro stimulation assays demonstrated a strong CCL2 production capacity of mononuclear immune cells and fibroblasts, but not epithelial or endothelial cells. Among a range of inflammatory mediators, only IL-1β (immune cells, fibroblasts) and tumour necrosis factor (TNF)-α (fibroblasts) were important CCL2 inducers. TNF-α, but not IL-17, strengthened the CCL2-inducing effect of IL-1β in fibroblasts. Accordingly, CCL2 levels positively correlated with both TNF-α and IL-1β serum levels in patients with SchS. Therapeutic IL-1β blockade decreased CCL2 blood levels in these patients as early as 1 week after the initiation of treatment.

CONCLUSIONS

CCL2 may be an important component of the pathogenetic cascade leading to bone alterations, and a suitable marker of disease activity in patients with SchS.

6-Phosphofructo-2-kinase/fructose-2,6-biphosphatase 4 is essential for p53-null cancer cells

The bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-4 (PFKFB4) controls metabolic flux through allosteric regulation of glycolysis. Here we show that p53 regulates the expression of PFKFB4 and that p53-deficient cancer cells are highly dependent on the function of this enzyme. We found that p53 downregulates PFKFB4 expression by binding to its promoter and mediating transcriptional repression via histone deacetylases. Depletion of PFKFB4 from p53-deficient cancer cells increased levels of the allosteric regulator fructose-2,6-bisphosphate, leading to increased glycolytic activity but decreased routing of metabolites through the oxidative arm of the pentose-phosphate pathway. PFKFB4 was also required to support the synthesis and regeneration of nicotinamide adenine dinucleotide phosphate (NADPH) in p53-deficient cancer cells. Moreover, depletion of PFKFB4-attenuated cellular biosynthetic activity and resulted in the accumulation of reactive oxygen species and cell death in the absence of p53. Finally, silencing of PFKFB4-induced apoptosis in p53-deficient cancer cells in vivo and interfered with tumour growth. These results demonstrate that PFKFB4 is essential to support anabolic metabolism in p53-deficient cancer cells and suggest that inhibition of PFKFB4 could be an effective strategy for cancer treatment.

Observation and understanding of anisotropic strain relaxation in selectively grown SiGe fin structures

The performance of heterogeneous 3D transistor structures critically depends on the composition and strain state of the buffer, channel and source/drain regions. In this paper we used an in-line high resolution x-ray diffraction (HRXRD) tool to study in detail the composition and strain in selectively grown SiGe/Ge fin structures with widths down to 20 nm. For this purpose we arranged fins of identical dimensions into larger arrays which were then analyzed using an x-ray beam several tens of micrometers in size. Asymmetric reciprocal space maps measured both parallel and perpendicular to the fins allowed us to extract the lattice parameters in all three spatial directions. Our results demonstrate an anisotropic in-plane strain state of the selectively grown SiGe buffer in case of narrower fins with significantly reduced relaxation in the direction along the fin. This observation was verified using nano-beam electron diffraction, and is explained based on the reduced probability for dislocation half-loops to evolve in trenches narrower than a few times the critical radius. Moreover, we introduce and discuss in detail a methodology for the determination of the composition in case of an anisotropic in-plane strain state which differs from the procedure commonly used for blanket layers. Our findings verify the importance of in-line HRXRD measurements for process development and monitoring as well as the fundamental study of relaxation and defect formation in confined volumes.

Designing and building oncolytic viruses

Oncolytic viruses (OVs) are engineered and/or evolved to propagate selectively in cancerous tissues. They have a dual mechanism of action; direct killing of infected cancer cells cross-primes anticancer immunity to boost the killing of uninfected cancer cells. The goal of the field is to develop OVs that are easily manufactured, efficiently delivered to disseminated sites of cancer growth, undergo rapid intratumoral spread, selectively kill tumor cells, cause no collateral damage and pose no risk of transmission in the population. Here we discuss the many virus engineering strategies that are being pursued to optimize delivery, intratumoral spread and safety of OVs derived from different virus families. With continued progress, OVs have the potential to transform the paradigm of cancer care.

FBXL4 defects are common in patients with congenital lactic acidemia and encephalomyopathic mitochondrial DNA depletion syndrome

Mutations in FBXL4 have recently been recognized to cause a mitochondrial disorder, with clinical features including early onset lactic acidosis, hypotonia, and developmental delay. FBXL4 sequence analysis was performed in 808 subjects suspected to have a mitochondrial disorder. In addition, 28 samples from patients with early onset of lactic acidosis, but without identifiable mutations in 192 genes known to cause mitochondrial diseases, were examined for FBXL4 mutations. Definitive diagnosis was made in 10 new subjects with a total of 7 novel deleterious variants; 5 null and 2 missense substitutions. All patients exhibited congenital lactic acidemia, most of them with severe encephalopathic presentation, and global developmental delay. Overall, FBXL4 defects account for at least 0.7% (6 out of 808) of subjects suspected to have a mitochondrial disorder, and as high as 14.3% (4 out of 28) in young children with congenital lactic acidosis and clinical features of mitochondrial disease. Including FBLX4 in the mitochondrial diseases panel should be particularly important for patients with congenital lactic acidosis.

[Salter innominate osteotomy : Indications, surgical technique, results]

The prevalence of congenital hip dysplasia in Germany is 2-4 % and that of hip dislocation is 0.5-1 %. If early therapy is not successful or the hip dysplasia or dislocation is diagnosed too late (children of over 1 year of age) surgical treatment is indicated to increase the femoral coverage. The innominate osteotomy, published by Robert B. Salter 1961, is a worldwide established technique to improve the lateral and ventral coverage of the femoral head in primary or secondary hip dysplasia or dislocation. In this paper we discuss Salter's technique and present indications, the perioperative procedure, operative modifications and operative extensions and demonstrate the anatomical requirements, postoperative biomechanical changes and long-term results.

Systemic availability of guanidinoacetate affects GABAA receptor function and seizure threshold in GAMT deficient mice

Deficiency of guanidinoacetate methyltransferase (GAMT) causes creatine depletion and guanidinoacetate accumulation in brain with the latter deemed to be responsible for the severe seizure disorder seen in affected patients. We studied electrical brain activity and GABAA mediated mechanisms of B6J.Cg-Gamt(tm1Isb) mice. Electrocorticographic (ECoG) monitoring of pharmacological treatments with ornithine (5 % in drinking water for 5-18 days) and/or Picrotoxin (PTX) (a GABAA receptor antagonist) (1.5 mg/kg, I.P.) in Gamt(MUT) and Gamt(WT) groups [n = 3, mean age (SEM) = 6.9 (0.2) weeks]. Mice were fitted with two frontal and two parietal epidural electrodes under ketamine/xylazine anesthesia. Baseline and test recordings were performed for determination of seizure activity over a 2 h period. The ECoG baseline of Gamt(MUT) exhibited an abnormal monotonous cortical rhythm (7-8 Hz) with little variability during awake and sleep states compared to wild type recordings. Ornithine treatment and also PTX administration led to a relative normalization of the Gamt(MUT) ECoG phenotype. Gamt(WT) on PTX exhibited electro-behavioral seizures, whereas the Gamt(MUT) did not have PTX induced seizures at the same PTX dose. Gamt(MUT) treated with both ornithine and PTX did not show electro-behavioral seizures while ornithine elevated the PTX seizure threshold of Gamt(MUT) mice even further. These data demonstrate: (1) that there is expression of electrical seizure activity in this Gamt-deficient transgenic mouse strain, and (2) that the systemic availability of guanidinoacetate affects GABAA receptor function and seizure thresholds. These findings are directly and clinically relevant for patients with a creatine-deficiency syndrome due to genetic defects in GAMT and provide a rational basis for a combined ornithine/picrotoxin therapeutic intervention.

The critical zeta potential of polymer membranes: how electrolytes impact membrane fouling

The zeta potential of membrane surfaces and the resulting electrostatic interactions are determining factors of membrane fouling. This publication presents the impact of salt concentration and pH value on these interactions.

Particle adsorption on a polyether sulfone membrane: how electrostatic interactions dominate membrane fouling

This study presents a new method focussing on electrostatic interactions during fouling of microfiltration membranes.

Glutamine and hyperammonemic crises in patients with urea cycle disorders

Blood ammonia and glutamine levels are used as biomarkers of control in patients with urea cycle disorders (UCDs). This study was undertaken to evaluate glutamine variability and utility as a predictor of hyperammonemic crises (HACs) in UCD patients.

METHODS

The relationships between glutamine and ammonia levels and the incidence and timing of HACs were evaluated in over 100 adult and pediatric UCD patients who participated in clinical trials of glycerol phenylbutyrate.

RESULTS

The median (range) intra-subject 24-hour coefficient of variation for glutamine was 15% (8-29%) as compared with 56% (28%-154%) for ammonia, and the correlation coefficient between glutamine and concurrent ammonia levels varied from 0.17 to 0.29. Patients with baseline (fasting) glutamine values >900 μmol/L had higher baseline ammonia levels (mean [SD]: 39.6 [26.2]μmol/L) than patients with baseline glutamine ≤ 900 μmol/L (26.6 [18.0]μmol/L). Glutamine values >900 μmol/L during the study were associated with an approximately 2-fold higher HAC risk (odds ratio [OR]=1.98; p=0.173). However, glutamine lost predictive significance (OR=1.47; p=0.439) when concomitant ammonia was taken into account, whereas the predictive value of baseline ammonia ≥ 1.0 upper limit of normal (ULN) was highly statistically significant (OR=4.96; p=0.013). There was no significant effect of glutamine >900 μmol/L on time to first HAC crisis (hazard ratio [HR]=1.14; p=0.813), but there was a significant effect of baseline ammonia ≥ 1.0 ULN (HR=4.62; p=0.0011).

CONCLUSIONS

The findings in this UCD population suggest that glutamine is a weaker predictor of HACs than ammonia and that the utility of the predictive value of glutamine will need to take into account concurrent ammonia levels.

Outwitting the series resistance in scanning spreading resistance microscopy

The performance of nanoelectronics devices critically depends on the distribution of active dopants inside these structures. For this reason, dopant profiling has been defined as one of the major metrology challenges by the international technology roadmap of semiconductors. Scanning spreading resistance microscopy (SSRM) has evolved as one of the most viable approaches over the last decade due to its excellent spatial resolution, sensitivity and quantification accuracy. However, in case of advanced device architectures like fins and nanowires a proper measurement of the spreading resistance is often hampered by the increasing impact of parasitic series resistances (e.g. bulk series resistance) arising from the confined nature of the aforementioned structures. In order to overcome this limitation we report in this paper the development and implementation of a novel SSRM mode (fast Fourier transform-SSRM: FFT-SSRM) which essentially decouples the spreading resistance from parasitic series resistance components. We show that this can be achieved by a force modulation (leading to a modulated spreading resistance signal) in combination with a lock-in deconvolution concept. In this paper we first introduce the principle of operation of the technique. We discuss in detail the underlying physical mechanisms as well as the technical implementation on a state-of-the-art atomic force microscope (AFM). We demonstrate the performance of FFT-SSRM and its ability to remove substantial series resistance components in practice. Eventually, the possibility of decoupling the spreading resistance from the intrinsic probe resistance will be demonstrated and discussed.

SREBP maintains lipid biosynthesis and viability of cancer cells under lipid- and oxygen-deprived conditions and defines a gene signature associated with poor survival in glioblastoma multiforme

Oxygen and nutrient limitation are common features of the tumor microenvironment and are associated with cancer progression and induction of metastasis. The inefficient vascularization of tumor tissue also limits the penetration of other serum-derived factors, such as lipids and lipoproteins, which can be rate limiting for cell proliferation and survival. Here we have investigated the effect of hypoxia and serum deprivation on sterol regulatory element-binding protein (SREBP) activity and the expression of lipid metabolism genes in human glioblastoma multiforme (GBM) cancer cells. We found that SREBP transcriptional activity was induced by serum depletion both in normoxic and hypoxic cells and that activation of SREBP was required to maintain the expression of fatty acid and cholesterol metabolism genes under hypoxic conditions. Moreover, expression of stearoyl-CoA desaturase, the enzyme required for the generation of mono-unsaturated fatty acids, and fatty acid-binding protein 7, a regulator of glioma stem cell function, was strongly dependent on SREBP function. Inhibition of SREBP function blocked lipid biosynthesis in hypoxic cancer cells and impaired cell survival under hypoxia and in a three-dimensional spheroid model. Finally, gene expression analysis revealed that SREBP defines a gene signature that is associated with poor survival in glioblastoma.

[Fusion in adolescent idiopathic scoliosis : Anterior, posterior or combined? One-stage or two-stage?]

Scoliosis is a complex, three-dimensional spinal deformity with various causes. Adolescent idiopathic scoliosis (AIS) is the most common form. Surgical treatment is indicated for curves greater than 45-50° meaured using the Cobb method. We can distinguish among posterior, anterior or combined surgical procedures. Today, the posterior, transpedicular approach has revolutionized scoliosis surgery. This review gives an overview of current surgical options in scoliosis treatment.

[Establishment of a Neonatal ECMO Programme on the Basis of a Special Training Programme--A 6-year Analysis]

BACKGROUND

Internationally the need for neonatal ECMO is decreasing and the Extracorporeal Life Support Organization (ELSO) recommends that centres providing neonatal ECMO should treat at least 6 children per year.

METHOD

After a one-year training programme and preparation of the clinical application, neonatal ECMO was established and subsequently 41 infants [median age 1 day (1-172 days), median weight 3.25 kg (1.27-5.79 kg)] with severe respiratory failure have been treated within a 6-year period (fall 2008-fall 2014). For rescue therapy we provide inhaled nitric oxide, high-frequency oscillation and other differentiated ventilator strategies. Parallel to the clinical use of ECMO all employees have been trained in a special programme at 3-monthly intervals.

RESULTS

By establishing an elaborate training programme and concentrating the treatment of critically ill newborns in one centre, the expertise of both running and preventing of neonatal ECMO due to pulmonary failure can be achieved. The diagnoses correlate to those of other centres which perform neonatal ECMO. 13 infants needed ECMO. The resulting overall survival rate was 11/12 (91.7%) infants treated with ECMO with a curative approach. All patients could be weaned from ECMO.

CONCLUSION

In the context of a specialised university hospital with all treatment options for critically ill newborns and with the establishment of a specialised training programme, neonatal ECMO for pulmonary failure can achieve equally good results in comparison to those of national and international ECMO centres.

[Treatment of early onset scoliosis : How far can we go?]

BACKGROUND

Recently, inconsistent definitions of early onset scoliosis (EOS) and a wide variety of treatment options have been observed.

OBJECTIVES

To clearly define the term EOS, to depict non-operative and operative treatment options, and to present the limitations of the boundaries of these techniques.

METHODS

Review of the literature, including conference presentations and expert opinions, in addition to personal experiences.

RESULTS

Early onset scoliosis (EOS) refers to spine deformity that is present before 10 years of age, regardless of etiology. All existing operative treatment options share a high risk of complications. Therefore, non-operative treatment should act as a time-buying approach to postpone surgery.

DISCUSSION

Awareness of treatment options and their specific indications, in addition to respecting each patient's individual needs and feasibilities, are crucial for the optimal outcome.

Fast Fourier transform scanning spreading resistance microscopy: a novel technique to overcome the limitations of classical conductive AFM techniques

A new atomic force microscopy (AFM)-based technique named fast Fourier transform scanning spreading-resistance microscopy (FFT-SSRM) has been developed. FFT-SSRM offers the ability to isolate the local spreading resistance (Sr) from the parasitic series resistance (probe, bulk, and back contact). The parasitic series resistance limits the use of classical SSRM in confined volumes and on very highly doped materials, two increasingly important situations in nanoelectronic components. This is realized via a force modulation at controlled frequency (affecting the SR component) and the extraction of the resistance amplitude at the modulation frequency, performing an FFT-based lock-in deconvolution. A systematic evaluation of the FFT-SSRM performances (i.e., resolution, dynamic range, sensitivity, and repeatability) is presented. The impact of various parameters (i.e., modulation frequency and amplitude or cutoff frequency of the current amplifier) on the performances of FFT-SSRM has been evaluated. We demonstrate the possibility to overcome sensitivity losses due to tip saturation in highly doped material and the utility of the technique in two different structures, presenting isolated and confined volumes.

Peripapillary Choroidal Thickness and Choroidal Area in Glaucoma, Ocular Hypertension and Healthy Subjects by SD-OCT

BACKGROUND

The exact pathogenesis of open angle glaucoma and ocular hypertension remains unclear. Hemodynamic influences are discussed as potential risk factors and the choroid may play an important role in the pathogenesis of open angle glaucoma or ocular hypertension. The current study investigates peripapillary choroidal thickness and choroidal area in patients with open angle glaucoma, subjects with ocular hypertension and healthy subjects using spectral-domain OCT. It furthermore assesses the association between peripapillary choroidal thickness and age, central corneal thickness, refractive error and intraocular pressure.

PATIENTS AND METHODS

Prospectively recorded data of 213 eyes of 177 open angle glaucoma patients, 73 eyes of 50 subjects with ocular hypertension and 152 eyes of 116 healthy control subjects were analyzed by fitting a linear mixed model including age and disease.

RESULTS

Peripapillary choroidal thickness was thinnest in glaucoma patients (125 µm), followed by healthy subjects (127 µm) and ocular hypertensive subjects (135 µm). A marginally significant difference was present between ocular hypertension and glaucoma (p=0.059). Thickest choroids were found superiorly and thinnest choroids inferiorly. Choroidal area was highest in the supero-nasal and lowest in the infero-temporal sectors. Choroidal thickness decreased with age, no significant correlation was evident between peripapillary choroidal thickness and refractive error or intraocular pressure. Peripapillary choroidal thickness and central corneal thickness are significantly negative correlated in healthy subjects.

CONCLUSIONS

There is a trend towards thicker choroids in ocular hypertensive subjects compared to healthy subjects or glaucoma patients. Thickest choroids are found superiorly, thinnest inferiorly. Interestingly, choroidal area is thinnest in the temporal-inferior sector, one of the regions where glaucomatous damage tends to start.

[Indications and concept of follow-up care of home-monitoring for premature and risk infants]

The pros and cons of home monitoring especially for premature infants with continuing apneic episodes and/or chronic lung disease are an ongoing discussion. The controversy spans socio-economic requirements, medical indication as well as patient and family needs. Here, the costs of home monitoring and follow-up care on the one hand and longer hospitalization times on the other need to be considered. This article aims to create a basis for this discussion by summarizing current evidence for the indications and considerations for differential diagnoses while also outlining the established follow-up program for these patients at the Dr. v. Hauner Children's Hospital at the Ludwig-Maximilians-University Munich, Germany.

Clinically stable very low birthweight infants are at risk for recurrent tissue glucose fluctuations even after fully established enteral nutrition

OBJECTIVE

In previous cases, we have observed occasional hypoglycaemic episodes in preterm infants after initial intensive care. In this prospective study, we determined the frequency and severity of abnormal tissue glucose (TG) in clinically stable preterm infants on full enteral nutrition.

METHODS

Preterm infants born at <1000 g (n=23; G1) and birth weight 1000-1500 g (n=18; G2) were studied at a postmenstrual age of 32±2 weeks (G1) and 33±2 weeks (G2). Infants were fed two or three hourly, according to a standard bolus-nutrition protocol, and continuous subcutaneous glucose measurements were performed for 72 h. Normal glucose values were assumed at ≥2.5 mmol/L (45 mg/dL) and ≤8.3 mmol/L (150 mg/dL). Frequency, severity and duration of glucose values beyond normal values were determined.

RESULTS

We observed asymptomatic low TG values in 39% of infants in G1 and in 44% in G2. High TG values were detected in 83% in G1 and 61% in G2. Infants in G1 experienced prolonged and more severe low TG episodes, and also more frequent and severe high TG episodes. In G1 and G2, 87% and 67% of the infants, respectively, showed glucose fluctuations characterised by rapid glucose increase followed by a rapid glucose drop after feeds. In more mature infants, glucose fluctuations were less pronounced and less dependent on enteral feeds.

CONCLUSIONS

Clinically stable well-developing preterm infants beyond their initial period of intensive care show interstitial glucose instabilities exceeding values as low as 2.5 mmol/L and as high as 8.3 mmol/L. This novel observation may play an important role for the susceptibility of these high-risk infants for the development of the metabolic syndrome.

TRIAL REGISTRATION NUMBER

German trial registration number DRKS00004590.

Photocatalytic degradation and toxicity evaluation of diclofenac by nanotubular titanium dioxide–PES membrane in a static and continuous setup

Diclofenac is a commonly used anti-inflammatory drug, which has been found in surface waters. TiO₂ nanotubes with a polymer microfiltration membrane showed high photocatalytic degradation of diclofenac combined with an excellent membrane performance and long term stability.

[Dorsal sagittal knee joint stability after endoprosthetic knee arthroplasty : Influence of preoperative joint stability and the type of implanted prosthesis]

BACKGROUND

Anterior knee pain is a known complication after implantation of a prosthesis and a possible reason is a posterior knee joint instability; however, the influence on postoperative stability is just as unknown as the possible influence of the type of prosthesis on postoperative stability.

AIM

This study investigated two possible preoperative and intraoperative influencing factors by determination of the preoperative joint stability and type of prosthesis.

[What do patients in Germany expect from their total knee arthroplasty?]

INTRODUCTION

Only 84 % of patients are satisfied with the operative result after total knee arthroplasty. A relevant reason is non-fulfilled preoperative expectations. Non-fulfilled preoperative expectations cannot be influenced postoperatively. So a knowledge of preoperative expectations and their influential factors is essential. The following study analyses the expectations and influential factors in patients before total knee arthroplasty in Germany.

MATERIAL AND METHODS

On the day before total knee replacement in 104 patients the following data were collected: school leaving level, comorbidities, articular knee function, psychological mood, health-related quality of life, and preoperative expectations. Statistical evaluation was done by factor analyses of expectations and independent variables, and correlation and regression analyses.

RESULTS

The following 4 factors of expectations resulted from the factor analyses: (i) relief of pain, (ii) increase of range of motion of the knee, (iii) better mobility, and (iv) better integration in social activities. In general patient expectations on the effects of a total knee replacement are high. Age and better integration in social activities correlate negatively, as also do age and better mobility. Body mass index and better integration in social activities correlate positively. The following formula analyses the expectations of better integration in social life: social expectations = 116-0.991 × age.

DISCUSSION

For the first time this study determines expectations and influential factors of patients who undergo a total knee replacement in Germany. By knowing the interaction of satisfaction and preoperative expectations, this knowledge is an essential condition to increase satisfaction after total knee replacement in the German population. Collecting the preoperative expectations of patients has to be an indispensable feature of the clinical practice in orthopaedic surgery.

[Differential diagnosis of hearing disorders]

Hearing impairment is considered as the most common impairment of a human sense system. According to WHO, 360 Million people worldwide were affected by hearing loss in 2012, out of which 91% were adults and 9% children.Hearing impairment can be triggered by various mechanisms, such as locally destructive processes (chronic otitis media, cholesteatoma or traumatic lesions) or systemic influences like infectious or ototoxic substances (measles, mumps, meningococcal meningitis or medication and industrial agents). Congenital dysplasia, perinatal complications and genetic modifications can lead to hearing loss as well. Moreover, the acute or chronic noise exposure associated with the changing spare time activities in industrial nations represents an increasingly significant source of hearing impairment. In order to achieve the best hearing rehabilita-tion, a specific differential diagnosis in each case is of significant importance.

Elevated phenylacetic acid levels do not correlate with adverse events in patients with urea cycle disorders or hepatic encephalopathy and can be predicted based on the plasma PAA to PAGN ratio

BACKGROUND

Phenylacetic acid (PAA) is the active moiety in sodium phenylbutyrate (NaPBA) and glycerol phenylbutyrate (GPB, HPN-100). Both are approved for treatment of urea cycle disorders (UCDs) - rare genetic disorders characterized by hyperammonemia. PAA is conjugated with glutamine in the liver to form phenylacetyleglutamine (PAGN), which is excreted in urine. PAA plasma levels ≥ 500 μg/dL have been reported to be associated with reversible neurological adverse events (AEs) in cancer patients receiving PAA intravenously. Therefore, we have investigated the relationship between PAA levels and neurological AEs in patients treated with these PAA pro-drugs as well as approaches to identifying patients most likely to experience high PAA levels.

METHODS

The relationship between nervous system AEs, PAA levels and the ratio of plasma PAA to PAGN were examined in 4683 blood samples taken serially from: [1] healthy adults [2], UCD patients of ≥ 2 months of age, and [3] patients with cirrhosis and hepatic encephalopathy (HE). The plasma ratio of PAA to PAGN was analyzed with respect to its utility in identifying patients at risk of high PAA values.

RESULTS

Only 0.2% (11) of 4683 samples exceeded 500 μg/ml. There was no relationship between neurological AEs and PAA levels in UCD or HE patients, but transient AEs including headache and nausea that correlated with PAA levels were observed in healthy adults. Irrespective of population, a curvilinear relationship was observed between PAA levels and the plasma PAA:PAGN ratio, and a ratio>2.5 (both in μg/mL) in a random blood draw identified patients at risk for PAA levels>500 μg/ml.

CONCLUSIONS

The presence of a relationship between PAA levels and reversible AEs in healthy adults but not in UCD or HE patients may reflect intrinsic differences among the populations and/or metabolic adaptation with continued dosing. The plasma PAA:PAGN ratio is a functional measure of the rate of PAA metabolism and represents a useful dosing biomarker.

[Active muscle extension testing of the hamstrings: reference values and impacting factors]

INTRODUCTION

Less muscle elasticity of the hamstrings increases the risk of muscle strain. Muscle balance is the purpose of muscle stretching. The active knee-extension test (AKE) represents an established test of muscle elasticity. For evaluating the test results standard values are necessary. The aim of this study is to measure standard values of the AKE test in a collective of healthy male and female fitness athletes and to determine factors of muscle elasticity.

MATERIAL AND METHODS

We performed the AKE test in 119 healthy fitness athletes (56 women, 63 men) evaluated biometric and anthropometric data, examined joint function in knee and hip activity scores (WOMAC, Lysholm score, Tegner score, UCLA-acitivity scale), psychological score (HADS scale) and clinical evidence of rheumatoid criteria (ACR). Unpaired t-test and multiple regressions were calculated.

RESULTS

The average knee extension deficit was as measured 31.6 ± 12.6° (men: 35.6 ± 10.4°; women 27.1 ± 13.5°, p = 0.0002), factors like "female gender", "physical work", "sports activities for many years", "hip flexion" and "body fat content" influence the muscle elasticity.

DISCUSSION

For the first time, standard values for the AKE test are available, allowing an estimation of muscle elasticity of the hamstrings. Factors like "female gender", "physical work" and "sports activities for many years" affect the muscle elasticity, while "body fat content" and "hip flexion" are combined to female gender and are considered as indirect factors of hamstring flexibility.

Direct imaging of 3D atomic-scale dopant-defect clustering processes in ion-implanted silicon

The fabrication of nanoscale semiconductor devices for use in future electronics, energy, and health is among others based on the precise placement of dopant atoms into the crystal lattice of semiconductors and their concurrent or subsequent electrical activation. Dopants are built into the lattice by fabrication processes like ion implantation, plasma-based doping, and thermal annealing. Throughout the fabrication processes fundamental phenomena like dopant diffusion, activation, and clustering occur concurrently with damaging and subsequently recovering the crystal lattice. These processes are described by atomic-scale mechanisms of ion-host atom interaction and have an immense impact on the electrical performance of the resulting devices. Insight in their fundamental nature is of utmost importance for optimizing the performance of nanoscale technologies. In this paper, we demonstrate direct three-dimensional imaging of boron clusters and atoms in crystal defects using field ion microscopy. Our approach allows for the first time the complete characterization of the size and crystallographic orientation of boron-decorated crystal defects. This new method opens a path to image a wide variety of dopant-cluster forms and hence to study the formation and dissolution of boron clusters in silicon on the atomic scale.