Cooperative dry-electrode sensors for multi-lead biopotential and bioimpedance monitoring

Cooperative sensors is a novel measurement architecture that allows the acquiring of biopotential signals on patients in a comfortable and easy-to-integrate manner. The novel sensors are defined as cooperative in the sense that at least two of them work in concert to measure a target physiological signal, such as a multi-lead electrocardiogram or a thoracic bioimpedance.This paper starts by analysing the state-of-the-art methods to simultaneously measure biopotential and bioimpedance signals, and justifies why currently (1) passive electrodes require the use of shielded or double-shielded cables, and (2) active electrodes require the use of multi-wired cabled technologies, when aiming at high quality physiological measurements.In order to overcome the limitations of the state-of-the-art, a new method for biopotential and bioimpedance measurement using the cooperative sensor is then presented. The novel architecture allows the acquisition of the aforementioned biosignals without the need of shielded or multi-wire cables by splitting the electronics into separate electronic sensors comprising each of two electrodes, one for voltage measurement and one for current injection. The sensors are directly in contact with the skin and connected together by only one unshielded wire. This new configuration requires one power supply per sensor and all sensors need to be synchronized together to allow them to work in concert.After presenting the working principle of the cooperative sensor architecture, this paper reports first experimental results on the use of the technology when applied to measuring multi-lead ECG signals on patients. Measurements performed on a healthy patient demonstrate the feasibility of using this novel cooperative sensor architecture to measure biopotential signals and compliance with common mode rejection specification accordingly to international standard (IEC 60601-2-47) has also been assessed.By reducing the need of using complex wiring setups, and by eliminating the presence of central recording devices (cooperative sensors directly sense and store the measured biosignals on the site), the depicted novel technology is a candidate to a novel generation of highly-integrated, comfortable and reliable technologies that measure physiological signals in real-life scenarios.

[Perioperative risk assessment of geriatric patients undergoing noncardiac surgery]

BACKGROUND

Older patients more often suffer perioperative complications than younger people. Especially geriatric patients who require emergency treatment represent a high-risk group. Therefore, perioperative risk assessment supports the treatment team in identifying patients at risk and in defining the treatment plan accordingly.

MATERIALS AND METHODS

A thorough medical history and clinical examination are pivotal elements of any risk stratification. The organ-specific risk assessment is primarily used to plan the surgical and anesthesiological procedures.

RESULTS

For a comprehensive risk assessment in geriatric patients, the organ-specific risk stratification is insufficient. Assessment instruments that reflect the idiosyncrasies of multidimensional disease in geriatric patients can complement risk stratification. These should include the assessment of multimorbidity, frailty, nutrition, activities of daily living, and cognition. In addition to risk prediction, geriatric assessment has the major advantage of providing both a diagnostic and a planning perspective. This allows the implementation of supporting measures for optimal perioperative care, which is the goal of any risk stratification. Risk scores provide a global assessment, but they have their limitations in predicting individual patient risk.

A balancing act: orchestrating amino-truncated and full-length p73 variants as decisive factors in cancer progression

p73 is the older sibling of p53 and mimics most of its tumor-suppressor functions. Through alternative promoter usage and splicing, the TP73 gene generates more than two dozen isoforms of which N-terminal truncated DNp73 variants have a decisive role in cancer pathogenesis as they outweigh the positive effects of full-length TAp73 and p53 in acting as a barrier to tumor development. Beyond the prevailing view that DNp73 predominantly counteract cell cycle arrest and apoptosis, latest progress indicates that these isoforms acquire novel functions in epithelial-to-mesenchymal transition, metastasis and therapy resistance. New insight into the mechanisms underlying this behavior reinforced the expectation that DNp73 variants contribute to aggressive cellular traits through both loss of wild-type tumor-suppressor activity and gain-of-function, suggesting an equally important role in cancer progression as mutant p53. In this review, we describe the novel properties of DNp73 in the invasion metastasis cascade and outline the comprehensive p73 regulatome with an emphasis on molecular processes putting TAp73 out of action in advanced tumors. These intriguing insights provoke a new understanding of the acquisition of aggressive traits by cancer cells and may help to set novel therapies for a broad range of metastatic tumors.

In vitro characterization of self-assembled anterior cruciate ligament cell spheroids for ligament tissue engineering

Tissue engineering of an anterior cruciate ligament (ACL) implant with functional enthesis requires site-directed seeding of different cell types on the same scaffold. Therefore, we studied the suitability of self-assembled three-dimensional spheroids generated by lapine ACL ligament fibroblasts for directed scaffold colonization. The spheroids were characterized in vitro during 14 days in static and 7 days in dynamic culture. Size maintenance of self-assembled spheroids, the vitality, the morphology and the expression pattern of the cells were monitored. Additionally, we analyzed the total sulfated glycosaminoglycan, collagen contents and the expression of the ligament components type I collagen, decorin and tenascin C on protein and for COL1A1, DCN and TNMD on gene level in the spheroids. Subsequently, the cell colonization of polylactide-co-caprolactone [P(LA-CL)] and polydioxanone (PDS) polymer scaffolds was assessed in response to a directed, spheroid-based seeding technique. ACL cells were able to self-assemble spheroids and survive over 14 days. The spheroids decreased in size but not in cellularity depending on the culture time and maintained or even increased their differentiation state. The area of P[LA-CL] scaffolds, colonized after 14 days by the cells of one spheroid, was in average 4.57 ± 2.3 mm(2). Scaffolds consisting of the polymer P[LA-CL] were more suitable for colonization by spheroids than PDS embroideries. We conclude that ACL cell spheroids are suitable as site-directed seeding strategy for scaffolds in ACL tissue engineering approaches and recommend the use of freshly assembled spheroids for scaffold colonization, due to their balanced proliferation and differentiation.

Resilience in patients and spouses faced with malignant melanoma. A qualitative longitudinal study

Life-threatening diseases like malignant tumours are associated with considerable existential distress. Little is known about the factors that promote resilience within these individuals. This longitudinal qualitative partner study aimed to analyse resilience as per Antonovsky's sense of coherence. Eight patients with malignant melanoma and their partners were interviewed. They were asked about their coping strategies, attitudes towards the meaning of life and their cancer, and comprehension of what is happening to them. The questions were asked shortly after their diagnosis was made and 6 months later. All interviews were audio-taped and later transcribed and analysed according to the method of qualitative content analysis described by P. Mayring. At baseline, the majority of statements made (261; patients = 141/spouses = 120) related to coping/manageability of disease, with only 26 statements (patients = 15/spouses = 11) related to meaning and 127 (patients = 64/spouses = 63) to comprehension. There were no significant differences between the responses of patients and their partners and no significant changes in the number of statements during the 6-month interview. The most significant theme that emerged was manageability of disease, with distraction the most commonly utilised coping skill. The comprehension and meaning themes were far less prevalent. Hence, support should focus on disease and situational manageability.

Long-term results of the augmented PFNA: a prospective multicenter trial

BACKGROUND

Pertrochanteric fractures are increasing and their operative treatment remains under discussion. Failures needing reoperations such as a cut-out are reported to be high and are associated with multiple factors including poor bone quality, poor fracture reduction and improper implant placement. The PFNA(®) with perforated blade offers an option for standardized cement augmentation with a PMMA cement to provide more stability to the fracture fixation. It remains unclear if the augmentation of this implant does any harm in a longer time span. This prospective multicenter study shows clinical and radiological results with this implant with a mean follow-up time of 15 months.

METHODS

In 5 European clinics, 62 patients (79 % female, mean age 85.3 years) suffering from an osteoporotic pertrochanteric fracture (AO 31) were treated with the augmented PFNA(®). The primary objectives were assessment of activities of daily living, pain and mobility. Furthermore, the X-rays were analyzed for the cortical thickness index, changes of the trabecular structure around the cement and the hip joint space.

RESULTS

The mean follow-up time was 15.3 months. We observed callus healing in all cases. The surgical complication rate was 3.2 % with no complication related to the cement augmentation. A mean volume of 3.8 ml of cement was injected and no complication was reported due to this procedure. 59.9 % reached their prefracture mobility level until follow-up. The mean hip joint space did not change significantly until follow-up and there were no signs of osteonecrosis in the follow-up X-rays. Furthermore, no blade migration was assessed.

CONCLUSION

This study makes us believe that the standardized augmentation of the PFNA with a perforated blade is a safe method to treat pertrochanteric femoral fractures. It leads to good functional results and is not associated with cartilage or bone necrosis.

Effect of ibandronate on spontaneous osteonecrosis of the knee: a randomized, double-blind, placebo-controlled trial

Based on this double-blind, placebo-controlled study, ibandronate has no beneficial effect on clinical and radiological outcome in patients with spontaneous osteonecrosis of the knee over and above anti-inflammatory medication.

INTRODUCTION

Observational studies suggest beneficial effects of bisphosphonates in spontaneous osteonecrosis (ON) of the knee. We investigated whether ibandronate would improve clinical and radiological outcome in newly diagnosed ON.

METHODS

In this randomized, double-blind, placebo-controlled trial, 30 patients (mean age, 57.3 ± 10.7 years) with ON of the knee were assigned to receive either ibandronate (cumulative dose, 13.5 mg) or placebo intravenously (divided into five doses 12 weeks). All subjects received additional treatment with oral diclofenac (70 mg) and supplementation with calcium carbonate (500 mg) and vitamin D (400 IU) to be taken daily for 12 weeks. Patients were followed for 48 weeks. The primary outcome was the change in pain score after 12 weeks. Secondary endpoints included changes in pain score, mobility, and radiological outcome (MRI) after 48 weeks.

RESULTS

At baseline, both treatment groups (IBN, n = 14; placebo, n = 16) were comparable in relation to pain score and radiological grading (bone marrow edema, ON). After 12 weeks, mean pain score was reduced in both ibandronate- (mean change, -2.98; 95% CI, -4.34 to -1.62) and placebo- (-3.59; 95% CI, -5.07 to -2.12) treated subjects (between-group comparison adjusted for age, sex, and osteonecrosis type, p = ns). Except for significant decrease in bone resorption marker (CTX) in ibandronate-treated subjects (p < 0.01), adjusted mean changes in all functional and radiological outcome measures were comparable between treatment groups after 24 and 48 weeks.

CONCLUSIONS

In patients with spontaneous osteonecrosis of the knee, bisphosphonate treatment (i.e., IV ibandronate) has no beneficial effect over and above anti-inflammatory medication.

Gender-specific hip fracture risk in community-dwelling and institutionalized seniors age 65 years and older

In this study of acute hip fracture patients, we show that hip fracture rates differ by gender between community-dwelling seniors and seniors residing in nursing homes. While women have a significantly higher rate of hip fracture among the community-dwelling seniors, men have a significantly higher rate among nursing home residents.

INTRODUCTION

Differences in gender-specific hip fracture risk between community-dwelling and institutionalized seniors have not been well established, and seasonality of hip fracture risk has been controversial.

METHODS

We analyzed detailed data from 1,084 hip fracture patients age 65 years and older admitted to one large hospital center in Zurich, Switzerland. In a sensitivity analysis, we extend to de-personalized data from 1,265 hip fracture patients from the other two large hospital centers in Zurich within the same time frame (total n = 2,349). The denominators were person-times accumulated by the Zurich population in the corresponding age/gender/type of dwelling stratum in each calendar season for the period of the study.

RESULTS

In the primary analysis of 1,084 hip fracture patients (mean age 85.1 years; 78% women): Among community-dwelling seniors, the risk of hip fracture was twofold higher among women compared with men (RR = 2.16; 95% CI, 1.74-2.69) independent of age, season, number of comorbidities, and cognitive function; among institutionalized seniors, the risk of hip fracture was 26% lower among women compared with men (RR = 0.77; 95% CI: 0.63-0.95) adjusting for the same confounders. In the sensitivity analysis of 2,349 hip fracture patients (mean age 85.0 years, 76% women), this pattern remained largely unchanged. There is no seasonal swing in hip fracture incidence.

CONCLUSION

We confirm for seniors living in the community that women have a higher risk of hip fracture than men. However, among institutionalized seniors, men are at higher risk for hip fracture.

Before and after hip fracture, vitamin D deficiency may not be treated sufficiently

Our findings show that only about 20% of seniors receive vitamin D supplementation prior to their index hip fracture or after the event. We further confirm the high prevalence of severe vitamin D deficiency in this population and show that those who receive supplementation have significantly higher 25-hydroxyvitamin D (25(OH)D) status.

INTRODUCTION

The aim of this study is to assess current practice in pre- and post-hip fracture care practice with respect to vitamin D supplementation.

METHODS

We surveyed 1,090 acute hip fracture patients age 65 and older admitted to acute care for hip fracture repair; 844 had serum 25-hydroxyvitamin D levels measured upon admission to acute care, and 362 agreed to be followed at 12 month after their hip fracture. Prevalence of vitamin D supplementation was assessed upon admission to acute care (at the time of hip fracture), upon discharge from acute care, and at 6 and 12 months follow-up.

RESULTS

Of 1,090 acute hip fracture patients (mean age 85 years, 78% women, 59 % community-dwelling), 19% had received any dose of vitamin D prior to the index hip fracture, 27% (of 854 assessed) at discharge from acute care, 22 % (of 321 assessed) at 6 month, and 21% (of 285 assessed) at 12 month after their hip fracture. At the time of fracture, 45% had 25(OH)D levels below 10 ng/ml, 81% had levels below 20 ng/ml, and 96% had levels below 30 ng/ml. Notably, 25(OH)D levels did not differ by season or gender but were significantly higher among 164 hip fracture patients, with any vitamin D supplementation compared with 680 without supplementation (19.9 versus 10.8 ng/ml; p < 0.0001).

CONCLUSION

Only about 20% of seniors receive vitamin D at the time of their fracture and after the event. This is despite the documented 81% prevalence of vitamin D deficiency. Interdisciplinary efforts may be warranted to improve vitamin D supplementation in seniors both before a hip fracture occurs and after.

[Validity of endoscopic ultrasonography-guided fine needle aspiration of mediastinal and abdominal lymph nodes in daily clinical practice]

BACKGROUND

According to recent clinical trials, EUS-FNA has a high diagnostic yield in case of mediastinal and abdominal lymphadenopathy. However, it is questionable, if the results of centers of excellence can be maintained in daily clinical practice.

METHODS

We retrospectively analyzed the results of 141 EUS-FNP in 121 patients (female 25, male 86; mean age 61,5 years, range 22-87) of 119 mediastinal and 22 abdominal lymph nodes, performed under routine conditions in daily clinical practice in a community hospital. Histopathological examination of operative specimens or clinical follow-up served as gold standard.

RESULTS

In 124/141 (80 %) of cases, adequate specimens could be obtained, irrespective of lymph node size. During follow-up, the rate of adequate specimens obtained increased from 77 % (2002-2006) to 98 % (2007-2010). Sensitivity and specifity for the diagnosis of malignancy was 77 and 100 % (diagnostic accuracy 92 %). During follow-up, a relevant learning curve could be observed with a significant increase in sensitivity (72 to 80 %).

CONCLUSION

In comparison to the results of centers of excellence, our diagnostic accuracy is slightly inferior. However, even in daily routine praxis, EUS-FNP is a safe and accurate method of sampling mediastinal and abdominal lymph nodes.

Quantum dynamics of solid Ne upon photo-excitation of a NO impurity: a Gaussian wave packet approach

A high-dimensional quantum wave packet approach based on Gaussian wave packets in Cartesian coordinates is presented. In this method, the high-dimensional wave packet is expressed as a product of time-dependent complex Gaussian functions, which describe the motion of individual atoms. It is applied to the ultrafast geometrical rearrangement dynamics of NO doped cryogenic Ne matrices after femtosecond laser pulse excitation. The static deformation of the solid due to the impurity as well as the dynamical response after femtosecond excitation are analyzed and compared to reduced dimensionality studies. The advantages and limitations of this method are analyzed in the perspective of future applications to other quantum solids.

All-optical tunability of microdisk lasers via photo-adressable polyelectrolyte functionalization

Photoactive materials are highly promising candidates for novel applications as they enable all-optical control of photonic devices. Photochromic molecules exhibit a reversible change of their dielectric function upon irradiation with light of proper wavelength. The trans- and cis-isomers of azobenzene exhibit different absorption properties due to the effect of the configuration on the polarizability of the molecule. Here, we introduce a novel molecular/semiconductor hybrid device which is fully tunable by all-optical means via the integration of a semiconductor microdisk into a photo-adressable polyelectrolyte material. We demonstrate that such polyelectrolyte superlattices can be used to tune semiconductor photonic resonators with high precision and without any significant degeneration of device performance. Moreover, we demonstrate an all-optically tunable laser based on this hybrid concept.

[A case of complex discharge medication]

At discharge of a 72 year old epileptic patient from the hospital, the clinician prescribed the switch from Orfiril® to Lamictal®. The general practitioner misinterpreted the confusing medication list and made handwritten changes. Later on, family members of the patient observed a discrepancy between the handwritten comments of the general practitioner and the medication list of the clinician. The medication could be re-evaluated in cooperation with the hospital pharmacy and the general practitioner. An early interdisciplinary collaboration would help improving patient safety.

Standardised cement augmentation of the PFNA using a perforated blade: A new technique and preliminary clinical results. A prospective multicentre trial

Pertrochanteric fractures are a rising major health-care problem in the elderly and their operative stabilisation techniques are still under discussion. Furthermore, complications like cut-out are reported to be high and implant failure often is associated with poor bone quality. The PFNA(®) with perforated blade offers a possibility for standardised cement augmentation using a polymethylmethacrylate (PMMA) cement which is injected through the perforated blade to enlarge the load-bearing surface and to diminish the stresses on the trabecular bone. The current prospective multicentre study was undertaken to evaluate the technical performance and the early clinical results of this new device. In nine European clinics, 59 patients (45 female, mean age 84.5 years) suffering from an osteoporotic pertrochanteric fracture (Arbeitsgemeinschaft für Osteosynthesefragen, AO-31) were treated with the augmented PFNA(®). Primary objectives were assessment of operative and postoperative complications, whereas activities of daily living, pain, mobility and radiologic parameters, such as cement distribution around the blade and the cortical thickness index, were secondary objectives. The mean follow-up time was 4 months where we observed callus healing in all cases. The surgical complication rate was 3.4% with no complication related to the cement augmentation. More than one-half of the patients reached their prefracture mobility level within the study period. A mean volume of 4.2ml of cement was injected. We did not find any cut-out, cut through, unexpected blade migration, implant loosening or implant breakage within the study period. Our findings lead us to conclude that the standardised cement augmentation using the perforated blade for pertrochanteric fracture fixation enhances the implant anchorage within the head-neck fragment and leads to good functional results.

[Psychological distress and quality of life in COPD-patients and their spouses]

OBJECTIVE

To investigate psychological distress, quality of life, and satisfaction with medical support of patients with COPD and their spouses.

METHOD

Questionnaires concerning psychological distress and quality of life were sent by mail to 97 patients and 54 spouses (43 couples).

RESULTS

We found increased scores of anxiety and depression. In terms of quality of life the patients reported significantly lower scores than their spouses. Patients as well as their spouses reported a high satisfaction about the given medical support.

CONCLUSION

Spouses of COPD patients are at increased risk for psychiatric morbidity und should therefore be included regularly in care programs.

Nucleoside diphosphate prodrugs

Nucleoside analogs are widely applied in antiviral and antitumor therapy. A severe limitation of these compounds arises from the need of biotransformation to the eventually active nucleoside triphosphates by stepwise addition of phosphate by kinases. This problem can be circumvented by employing reversibly masked nucleotides (prodrugs). However, the known concepts to bypass enzyme activation have almost exclusively been applied to nucleoside monophosphates. Here, we report on the transfer of the bis-(acyloxybenzyl)-concept (BAB-concept) from nucleoside monophosphates to nucleoside diphosphates (NDP) of the anti HIV drugs AZT and d4T. After successful synthesis and isolation of the compounds (BAB-NDPs), it was shown that these compounds exhibit promising hydrolytic properties ranging from high stability at physiological pH to very low stability in cellular extracts. Furthermore, we demonstrated that for some of the compounds a selective cleavage mechanism resulted in the exclusive delivery of the corresponding nucleoside diphosphate within 15 minutes without any degradation of the pyrophosphate unit, which is a unique result in the field of NDP-prodrugs.

[Focal laser photocoagulation in patients with diabetic macular edema after pretreatment with triamcinolone: 6-month results]

PURPOSE

The aim of this study was to analyse the 6-months results of focal laser photocoagulation (LC) applied after previous intravitreal injection of triamcinolone in eyes with non-proliferative diabetic retinopathy and clinically significant diabetic macular edema (DME).

PATIENTS AND METHODS

32 eyes (32 patients) with DME were included in this study. The number of laser treatments was: 1 in 14 eyes, 2 in 11, 3 in 4 eyes, 4 in 2 and 5 in 1 eye. The first LC was performed at a median of 17 days (mean: 20.3 +/- 6.5, range: 14 - 42 days) after triamcinolone injection. The second, if necessary, at a median of 32.5 (mean: 45.6 +/- 36.6, range: 22 - 144) days after injection.

RESULTS

Mean logMAR visual acuity improved from baseline 0.56 (median: 0.48; 95 %-confidence interval [CI]: 0.41 - 0.71) to 0.47 (median: 0.40, CI: 0.36 - 0.58) after 1 month, and 0.49 (median: 0.40, CI: 0.38 - 0.61) at 3 months, and 0.47 (median: 0.40, CI: 0.36 - 0.58) at 6 months (p < 0.0065). Mean central retinal thickness (OCT-CRT) of optical coherence tomography measurements improved from 417 microm (median: 402.5, CI: 375 - 460 microm) at baseline to 301 microm (median: 280, CI: 271 - 331) at 1 month, 318 microm (median: 305, CI: 276 - 360) at 3 months and 348 microm (median: 329.5, CI: 299 - 398 microm) at 6 months (p = 0.0256). A second combination therapy was performed in 1 eye 3 months after the first injection. In 7 / 32 eyes (22 %) further injections and LC were indicated after 6 months. 8 / 32 eyes received newly prescribed antiglaucomatous medication and 4 / 32 eyes cataract surgery during follow-up.

CONCLUSION

Focal LC after previous injection of triamcinolone results in an early and in most cases persistent functional improvement in eyes with DME.

Hemorrhagic complications after intravitreal injections of ranibizumab in patients under coumarin-type anticoagulation

BACKGROUND

It was the aim of this retrospective study to evaluate the risk of extra- or intraocular hemorrhages associated with intravitreal injections of ranibizumab in patients receiving anticoagulation therapy with coumarin derivatives.

PATIENTS AND METHODS

149 injections were performed in 50 patients who had preoperatively been instructed to continue their normal anticoagulation dose scheme. The coagulation status (Quick's time and/or INR) was checked the day before or on the day of injection. Clinical examinations including anterior and posterior segment biomicroscopy were performed in all patients within 24 hours before and 1 day, 1 week and 1 month after injection.

RESULTS

The average Quick value at the time of injection was 27 % +/- 15 % (median: 22 %, 95 % confidence interval: 24.6 - 29.3 %, range: 6 - 95 %), the average INR 2.32 +/- 0.79 (median: 2.2, 95 % confidence interval: 2.17 - 2.47 range:0.8 - 4.9). Minor subconjunctival hemorrhages were observed in 26 of 149 injections (17.4 %). New intraocular hemorrhages or other coagulation-related complications associated to the injection therapy were not observed.

CONCLUSIONS

Our study suggests that there is a low risk of coagulation-related complications in patients receiving intravitreal injections of ranibizumab even if the use of cumarin derivatives is continued within the normal therapeutic range.

Spectroscopic measurements with dispersion encoded full range frequency domain optical coherence tomography in single- and multilayered non-scattering phantoms

In this study, depth resolved measurements of absorption profiles in the wavelength range of 800 nm with a bandwidth of 140 nm are demonstrated using high speed spectroscopic frequency domain OCT(SOCT) and a full range reconstruction algorithm (dispersion encoded full range, DEFR). The feasibility of the algorithm for SOCT is tested in simulation and experiment. With proper calibration, SOCT with DEFR is able to extract absolute, depth resolved absorption profiles over the whole wavelength range at once without the need of tuning and performing measurements at single wavelengths sequentially. The superior acquisition speed and better phase stability in frequency domain as compared to time domain results in a better reproducibility and practicability for spectroscopic measurements. In addition, high acquisition speed in excess of 20 kHz allows to measure absorption dynamics with 50 micros time resolution, which might be useful for the investigation of pharmacokinetics or pharmacodynamics. SOCT of approximately 600 microm thick single- and multilayered, weakly scattering phantoms with varying absorption in the range of 5-80 cm(-1), equivalent to blood absorption in capillaries, is presented. SOCT measurements are compared with those using a spectrometer in transmission mode. For Indocyanine Green (ICG), a dynamic absorption measurements are demonstrated.

[Thiazolidinediones and skeletal health]

The insulin-sensitizing thiazolidinediones are effective drugs to achieve glycemic control in patients with type 2 diabetes. Results from preclinical studies have demonstrated that activation of PPAR-gamma inhibits primarily bone formation by diverting mesenchymal stem cells to the adipocytic rather than to the osteogenic lineage. In humans studies demonstrated accelerated bone loss, impaired bone mineral density as well as an increased fracture risk for thiazolidinedione users, mostly for women. As a consequence of these observations, clinicians have to carefully assess the fracture risk in patients with type 2 diabetes before starting a therapy with thiazolidinediones.

The disc damage likelihood scale (DDLS): interobserver agreement of a new grading system to assess glaucomatous optic disc damage

BACKGROUND

The disc damage likelihood scale (DDLS) is a new grading system to estimate the amount of optic disc damage in glaucoma patients. The objective of this study was to assess the interobserver agreement of the DDLS and the cup/disc ratio.

PATIENTS AND METHODS

The reproducibility of the DDLS and the cup/disc ratio was measured by two masked observers (one glaucoma specialist and one of two resident physicians in their first 6 months of training) staging 42 eyes of 25 patients with glaucoma or ocular hypertension. Disc size, cup/disc ratio and DDLS were documented and the Cohen's kappa was calculated as a measure for interobserver agreement.

RESULTS

The interobserver agreement for the cup/disc ratio was good (Cohen's kappa 0.803). For the DDLS, the interobserver agreement was even better (Cohen's kappa 0.902).

DISCUSSION

Unlike the cup/disc ratio, which focuses on the excavation, the DDLS is based directly on the thickness of the neuroretinal rim and takes into account the optic disc size. Therefore, the DDLS estimates the glaucomatous damage of the optic disc more precisely than the currently used method. Although this new grading system is more complicated to use in clinical practice, the interobserver agreement for the DDLS in our study setting was very good.

Concomitant field terms for asymmetric gradient coils: consequences for diffusion, flow, and echo-planar imaging

As a consequence of the Maxwell equations, linear field gradients are accompanied by additional spatially dependent field components. A description of the Maxwell field terms is presented which explicitly takes into account the asymmetry of the gradient coil. It is shown both theoretically and experimentally that, in contrast to symmetric coils, an asymmetric coil generates concomitant field terms of zeroth and first order in space. Artifacts induced by concomitant fields can be much more pronounced for asymmetric coil designs than for symmetric ones. For the strong gradient amplitudes available on modern MR systems the effect of these concomitant magnetic fields on the evolution of magnetization has to be taken into consideration in a variety of NMR acquisition techniques. The formalism is used experimentally to compensate for artifacts observed in three different imaging methods: an image shift in standard echo planar imaging (EPI), an echo shift in diffusion-weighted EPI, and a phase shift in a flow quantification technique based on phase contrast images.

Synthesis of C8-modified 2''-deoxyadenosine with carcinogenic arylamines

The synthesis of phosphoramidites of C8-modified 2'-deoxyadenosine with carcinogenic arylamines p-anisidine and 4-aminobiphenyl is described. Two different methods were studied related to the glycon and base protection groups.

Cyclopentane-nucleobase coupling in the synthesis of carbocyclic L-nucleosides: is a SN2-reaction an alternative to the Mitsunobu-reaction?

Several carbocyclic L-nucleosides have been synthesized by coupling a cyclopentane-system with heterocycles according to a modified Mitsunobu-protocol. This reaction gave two regioisomers, the N1-alkylated product and an unwanted O(2)-product. A simple S(N)2-reaction has been investigated as an alternative for such couplings.

Intracellular trapping of cycloSal-pronucleotides by enzymatic cleavage

A new synthesis for cycloSal-pronucleotides bearing enzymatically cleavable triggers is presented. This trigger is introduced to trap the pronucleotide inside cells. The general concept and hydrolysis data in different media are discussed.

New cycloAmb-nucleoside phosphonate prodrugs

cycloSal- and cycloAmb-nucleoside phosphonate prodrugs of PMEA were synthesized and characterized. Each of these compounds showed different disadvantages in hydrolysis. Thus, a new series of cycloAminobenzyl(cycloAmb)-PMEA prodrugs was synthezised and studied with regard to their hydrolysis properties and biological activity.