Simulating intervertebral disc cell behaviour within 3D multifactorial environments.

MOTIVATION: Low back pain is responsible for more global disability than any other condition. Its incidence is closely related to intervertebral disc (IVD) failure, which is likely caused by an accumulation of microtrauma within the IVD. Crucial factors in microtrauma development are not entirely known yet, probably because their exploration in vivo or in vitro remains tremendously challenging. In silico modelling is, therefore, definitively appealing, and shall include approaches to integrate influences of multiple cell stimuli at the microscale. Accordingly, this study introduces a hybrid Agent-based (AB) model in IVD research and exploits network modelling solutions in systems biology to mimic the cellular behaviour of Nucleus Pulposus cells exposed to a 3D multifactorial biochemical environment, based on mathematical integrations of existing experimental knowledge. Cellular activity reflected by mRNA expression of Aggrecan, Collagen type I, Collagen type II, MMP-3 and ADAMTS were calculated for inflamed and non-inflamed cells. mRNA expression over long periods of time is additionally determined including cell viability estimations. Model predictions were eventually validated with independent experimental data. RESULTS: As it combines experimental data to simulate cell behaviour exposed to a multifactorial environment, the present methodology was able to reproduce cell death within 3 days under glucose deprivation and a 50% decrease in cell viability after 7 days in an acidic environment. Cellular mRNA expression under non-inflamed conditions simulated a quantifiable catabolic shift under an adverse cell environment, and model predictions of mRNA expression of inflamed cells provide new explanation possibilities for unexpected results achieved in experimental research. AVAILABILITYAND IMPLEMENTATION: The AB model as well as used mathematical functions were built with open source software. Final functions implemented in the AB model and complete AB model parameters are provided as Supplementary Material. Experimental input and validation data were provided through referenced, published papers. The code corresponding to the model can be shared upon request and shall be reused after proper training. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

A piecewise regression approach for determining biologically relevant hydraulic thresholds for the protection of fishes at river infrastructure.

A piecewise regression approach was used to objectively quantify barotrauma injury thresholds in two physoclistous species, Murray cod Maccullochella peelii and silver perch Bidyanus bidyanus, following simulated infrastructure passage in a barometric chamber. The probability of injuries such as swimbladder rupture, exophthalmia and haemorrhage, and emphysema in various organs increased as the ratio between the lowest exposure pressure and the acclimation pressure (ratio of pressure change, R(NE:A) ) reduced. The relationship was typically non-linear and piecewise regression was able to quantify thresholds in R(NE:A) that once exceeded resulted in a substantial increase in barotrauma injury. Thresholds differed among injury types and between species but by applying a multispecies precautionary principle, the maintenance of exposure pressures at river infrastructure above 70% of acclimation pressure (R(NE:A) of 0·7) should protect downstream migrating juveniles of these two physoclistous species sufficiently. These findings have important implications for determining the risk posed by current infrastructures and informing the design and operation of new ones.

Swiss paediatric dentists' preferences and experience on the use of articaine and other local/topical anaesthetics.

PURPOSE: This study was conducted to explore the preference and experience of paediatric dentists based in Switzerland regarding the use of articaine and other local and topical anaesthesia. METHODS: An 18-question survey was developed, piloted, and distributed to the members of the Swiss association of paediatric dentistry (n = 460). The following information were collected: most used local anaesthetic in different age groups, time needed to inject a full ampule, frequency of observed local and systemic side effects, application of topical anaesthetic prior to injection, time waited between application and the injection, and perceived effectiveness of topical anaesthetic. The dentists' responses were analysed with logistic regressions reporting odds ratios (OR) and 95% confidence intervals (CI) at 5%. RESULTS: The response rate was 37% (n = 168) out of the 460 questionnaires sent, with the responders being predominantly female (67%) and 47-year-old on average. More than 80% of the dentists used articaine in all age groups. 45% of responders took longer than 60 s to inject a full ampule. Local and systemic side-effects were observed by 82% and 28% of respondents respectively, although the nature and the significance of those were not detailed due to the anonymous nature of the questionnaire. Significantly less local adverse effects were seen for older children (p = 0.04) and among dentists with more years of experience (p = 0.01). Most responders applied topical anaesthetic and half of them waited longer than 60 s before injection. CONCLUSIONS: Articaine is a widely used local anaesthetic by the studied group of Swiss paediatric dentists regardless of patient's age. The use of topical anaesthetic before injection is a common practice with good perceived effectiveness.

Quetiapine in adolescents with non-affective psychotic disorders: an open-label trial.

INTRODUCTION: There is a need for more studies on the clinical effectiveness, tolerability and pharmacokinetics of atypical antipsychotics in adolescents with psychotic disorders, as this represents a vulnerable and difficult population to treat. According to recent concerns regarding disabling side effects of antipsychotics, particularly weight gain, further monitoring of their safety profiles is needed. This situation prompted the authors to carry out an investigation on the clinical effectiveness of quetiapine in psychotic adolescents. METHODS: 23 adolescents (13-18 years old) with psychotic disorders participated in a 12-week open label trial, including 6 visits assessing clinical efficacy, tolerability and safety of quetiapine (50-750 mg daily). RESULTS: Adolescents were treated with lower doses compared to adults. Significant decreases in CGI and PANSS total scores were observed after both 4 and 12 weeks of quetiapine treatment compared to baseline. Sedation was the main adverse effect, but medication was generally well tolerated. Irregular compliance, (as assessed by pill counts, a questionnaire and by plasma quetiapine concentration monitoring), and alcohol and/or cannabis consumption were factors identified in this study which add to the difficulty in treating this population. DISCUSSION: The results of the present study help to consolidate evidence of the usefulness of quetiapine as a treatment for adolescents with psychotic disorders. However, this study also highlights the issues encountered in treating this group, including the presence of comorbidities such as drug abuse.

Generalist niche, specialist strategy: the diet of an Australian percichthyid.

Dietary analysis revealed that an impoundment population of Australian bass Macquaria novemaculeata holds a generalist niche, but one arising from persistent individual specialization and interindividual variation. This 'individual specialist' strategy appeared adaptive, but the strength of individual specialization was largely independent of variation in diet composition, except during blooms of Daphnia sp. Diet composition and dietary overlap showed only moderate ontogenetic variation, and niche breadth showed no relationship with ontogeny. Macquaria novemaculeata showed an asymmetric predator and prey size distribution, consistent with many aquatic predators, with positive relationships between fish size and average, maximum and minimum prey size. There was no asymmetry in the relative size-based niche breadths of individuals, however, which indicates that the niche is a fixed 'window' of relative prey sizes. The difference in the dietary niche and prey-size relationships of M. novemaculeata at the population and individual levels highlights the necessity of assessing the niche at both these levels.

Evidence-Based Network Modelling to Simulate Nucleus Pulposus Multicellular Activity in Different Nutritional and Pro-Inflammatory Environments.

Initiation of intervertebral disc degeneration is thought to be biologically driven. This reflects a process, where biochemical and mechanical stimuli affect cell activity (CA) that compromise the tissue strength over time. Experimental research enhanced our understanding about the effect of such stimuli on different CA, such as protein synthesis or mRNA expression. However, it is still unclear how cells respond to their native environment that consists of a "cocktail" of different stimuli that might locally vary. This work presents an interdisciplinary approach of experimental and in silico research to approximate Nucleus Pulposus CA within multifactorial biochemical environments. Thereby, the biochemical key stimuli glucose, pH, and the proinflammatory cytokines TNF-α and IL1ß were considered that were experimentally shown to critically affect CA. To this end, a Nucleus Pulposus multicellular system was modelled. It integrated experimental findings from in vitro studies of human or bovine Nucleus Pulposus cells, to relate the individual effects of targeted stimuli to alterations in CA. Unknown stimulus-CA relationships were obtained through own experimental 3D cultures of bovine Nucleus Pulposus cells in alginate beads. Translation of experimental findings into suitable parameters for network modelling approaches was achieved thanks to a new numerical approach to estimate the individual sensitivity of a CA to each stimulus type. Hence, the effect of each stimulus type on a specific CA was assessed and integrated to approximate a multifactorial stimulus environment. Tackled CA were the mRNA expressions of Aggrecan, Collagen types I & II, MMP3, and ADAMTS4. CA was assessed for four different proinflammatory cell states; non-inflamed and inflamed for IL1ß, TNF-α or both IL1ß&TNF-α. Inflamed cell clusters were eventually predicted in a multicellular 3D agent-based model. Experimental results showed that glucose had no significant impact on proinflammatory cytokine or ADAMTS4 mRNA expression, whereas TNF-α caused a significant catabolic shift in most explored CA. In silico results showed that the presented methodology to estimate the sensitivity of a CA to a stimulus type importantly improved qualitative model predictions. However, more stimuli and/or further experimental knowledge need to be integrated, especially regarding predictions about the possible progression of inflammatory environments under adverse nutritional conditions. Tackling the multicellular level is a new and promising approach to estimate manifold responses of intervertebral disc cells. Such a top-down high-level network modelling approach allows to obtain information about relevant stimulus environments for a specific CA and could be shown to be suitable to tackle complex biological systems, including different proinflammatory cell states. The development of this methodology required a close interaction with experimental research. Thereby, specific experimental needs were derived from systematic in silico approaches and obtained results were directly used to enhance model predictions, which reflects a novelty in this research field. Eventually, the presented methodology provides modelling solutions suitable for multiscale approaches to contribute to a better understanding about dynamics over multiple spatial scales. Future work should focus on an amplification of the stimulus environment by integrating more key relevant stimuli, such as mechanical loading parameters, in order to better approximate native physiological environments.

Significance of tumor marker determinations in the primary therapy of ovarian cancer.

In 296 patients with primary ovarian cancer the sensitivity and specificity of CA125 and carcinoembryonic antigen (CEA) were determined. High CA125 values can be found in serous cystadenocarcinomas, CA125 can also be detected in patients with mucinous carcinomas. Only in cases negative for CA125 should other tumor markers be determined. As a second choice CA72-4 is proposed, since because of its low sensitivity of only 9% CEA should no longer be regularly determined in ovarian cancer. Preoperatively determined CA125 values show no prognostic significance in primary ovarian cancer. The means of CA125 half life in primary therapy demonstrated prognostic significance, and therefore patients with a worse prognostic outcome can be spared the adverse side effects of ineffective chemotherapy.

Prognostic significance of squamous cell carcinoma (SCC) antigen in primary advanced and recurrent cervical carcinoma.

Between January 1986 and June 1992 56 patients with cervical carcinoma were treated with cytostatic drugs in our department. In all patients showing primary response to therapy, the SCC and CEA levels fell rapidly to normal after one or two cycles. In contrast, clinical remission was not obtained in those patients with levels which remained high or rose again following an initial decrease. Using tumor markers, treatment can be individualized so that, cases of therapy failure or further tumor progression can be detected early and the patient can be spared the severe side effects of treatment.

CA125 based diagnosis and therapy in recurrent ovarian cancer.

Approximately 85% of patients with advanced ovarian cancer will experience recurrence of the disease. In 311 patients CA125 serum levels were determined at follow up investigation in our department. A sensitivity of 92% and specificity of 89% were calculated. Reflecting the further course of disease, specificity could be increased up to 97%. Using 25 U/ml/month as the upper limit of grade of CA125 increase, a 100% specificity for detecting recurrence could be achieved. In conclusion, recurrence diagnosis and even therapy should be started in cases of either significantly raised CA125 levels or elevated grade of CA125 increase.

Significance of the tumour markers CA 125 II, CA 72-4, CASA and CYFRA 21-1 in ovarian carcinoma.

We compared the tumour marker CA 72-4 and the new markers CASA and CYFRA 21-1 with the established marker CA 125II in follow-up care and control of efficacy of treatment in ovarian cancer in order to determine whether there are differences in recognizing ovarian carcinomas of different histological type. The investigation was done retrospectively on serum samples frozen at -80 degrees C obtained from 262 subjects, among them 50 healthy women, 53 sera with benign gynecological diseases and 159 sera with ovarian cancer, 72 of them at the time of primary diagnosis. We used commercially available kits: CA 125 II: Centocor RIA, CASA: Medac EIA, CA 72-4: Centocor RIA and CYFRA 21-1: Boehringer EnzymunR ELISA. Fixing specificity at 95% versus benign gynecological diseases as a clinically relevant reference group, we found cut-off values of 160 U/mL for CA 125II, 6.5 U/mL for CASA, 6.8 U/mL for CA 72-4 and 2.4 ng/ml for CYFRA 21-1. Based on this specificity we can compare the corresponding sensitivities at the time of primary diagnosis (n = 72): CA 125 II 47%, CA 72-4 47%; CASA 31% and CYFRA 21-1 44%. Regarding histological types of ovarian carcinomas, we found a sensitivity of 50% for CA 125 II and CASA, 36% for CA 72-4 and 33% for CYFRA 21-1 in serous ovarian cancer (n = 53), 21% for CA 125 II and CASA, 36% for CYFRA 21-1 and 43% for CA 72-4 for mucinous ovarian cancer (n = 27). Serous ovarian carcinomas were classified by higher FIGO-stages than mucinous ovarian carcinomas. Additional sensitivities were found at the time of primary diagnosis for the combination of CA 125 II and CA 72-4 and in serous ovarian cancer for CA 125 II and CASA. According to our results, at the time of primary diagnosis the combined determination of CA 125 II and CA 72-4 is useful. If both are negative, determination of CASA can be helpful. For follow-up care and control of efficacy of treatment the preoperative positive or leading marker is sufficient.

Serum levels of CA 125 and TPS during treatment of ovarian cancer.

Two hundred and sixty ovarian cancer patients (including all FIGO stages) were enrolled in a prospective multicentre study. In this interim study we analyzed 206 patients receiving combined chemotherapy for at least 3 courses for two-year overall survival (OS). CA 125 and TPS were applied for monitoring treatment and the relationship between marker levels, marker changes and clinical assessments was established. Preoperative CA 125 or TPS levels were not correlated with OS in FIGO stage I and II patients. After 3 chemotherapy courses the marker levels were not correlated with OS in stage I and II. Partial debulking in stage II patients was a bad prognostic factor. CA 125 or TPS levels (using a CA 125 discrimination level of 25 kU/l and a TPS discrimination level of 100 U/l) after 3 courses of chemotherapy were highly significantly correlated with OS in FIGO stages III and IV patients: CA 125 two-year OS 67% versus 26% (p < 0.0001) and TPS two-year OS 55% versus 22% (p < 0.0001). The prognostic value of CA 125 levels after 3 chemotherapy courses could be further increased by combining CA 125 and TPS levels. When both CA 125 and TPS levels were below their respective discrimination levels, the two-year overall survival was 75%. When both levels were above the discrimination level, the two-year overall survival was only 17%.

Prognostic significance of CA 125 and TPS levels after chemotherapy in ovarian cancer patients.

The analysis of survival data of patients with epithelial ovarian cancer proved that both CA 125 and TPS were good markers for clinical outcome prediction. Patients receiving chemotherapy were analyzed for 2-year overall survival (OS). Kaplan-Meier survival analysis showed highly significant differences in OS between patients with stage I+II (survival for 2 years 68%) and stage III+IV (survival for 2 years 33%; p = 0.0008). CA 125 levels above or below 35 kU/I and TPS levels above or below 80 U/l after 3 chemotherapy courses were not significantly correlated with OS in stage I+II patients (p = 0.06 respectively 0.07). However, in the subgroup of patients with stage III+IV the cut-off levels of CA 125 and TPS were excellent discriminators of OS: With CA 125 levels below the cut-off 52% of the patients survived, while with CA 125 levels above the cut-off only 13% survived (p < 0.0001). With TPS levels below the cut-off 49% of the patients survived, while with levels above the cut-off only 19% of the patients survived (p < 0.0001). In the subset of patients with CA 125 levels less than 35 kU/I after 3 chemotherapy courses (n = 50) analysis of their TPS levels allowed further discrimination of the prognostic significance. With TPS levels below the cut-off 63% of the patients survived, while 35% of the patients survived with TPS levels above the cut-off. The sum value of CA 125 and TPS cut-off values (115) as discriminator correlated even better with survival rate: With levels below this sum value 63% of the patients survived, while this was only 17% with sum values above the summed cut-off level (p = 0.0004). The extent to which the tumor was removed at operation also correlated with the 2 years survival rate. None of the patients with a staging laparotomy (n = 10) showed a 2-years survival. The difference in OS between patients with complete debulking and partial debulking was significant: OS 51% versus 23% (p = 0.027). Prognosis was not significantly correlated with histological type.

Overcoming barriers to evaluating federal health education and training programs.

The effectiveness of federal programs is often difficult to measure because many are authorized to support a broad range of objectives without common outcome goals, measures, and reporting requirements. When direct program evaluation is not possible, it may be possible instead to evaluate how well the strategies that federal programs support have worked to achieve certain objectives. This alternative to direct program evaluation was demonstrated in a General Accounting Office review of federal health professions education and training programs within Titles 7 and 8 of the Public Health Service Act.

[Clinical experience in the use of modern inhalation anaesthetic enflurane (author's transl)]. / Klinische Erfahrungen mit dem modernen Inhalationsnarkotikum Enfluran.

A clinical investigation was carried out on the findings obtained during 120 anaesthetics conducted with enflurane. The anaesthetic properties and the effects of enflurane on respiration, heart and circulation, liver, kidney, haematopoesis, clotting mechanisms and carbohydrate metabolism were evaluated. The results are discussed and the data compared with those of halothane for better quantitative assessment.

Optimisation of the mean boat velocity in rowing.

In rowing, motor learning may be facilitated by augmented feedback that displays the ratio between actual mean boat velocity and maximal achievable mean boat velocity. To provide this ratio, the aim of this work was to develop and evaluate an algorithm calculating an individual maximal mean boat velocity. The algorithm optimised the horizontal oar movement under constraints such as the individual range of the horizontal oar displacement, individual timing of catch and release and an individual power-angle relation. Immersion and turning of the oar were simplified, and the seat movement of a professional rower was implemented. The feasibility of the algorithm, and of the associated ratio between actual boat velocity and optimised boat velocity, was confirmed by a study on four subjects: as expected, advanced rowing skills resulted in higher ratios, and the maximal mean boat velocity depended on the range of the horizontal oar displacement.

Assessment of nitrification potential in ground water using short term, single-well injection experiments.

Nitrification was measured within a sand and gravel aquifer on Cape Cod, MA, using a series of single-well injection tests. The aquifer contained a wastewater-derived contaminant plume, the core of which was anoxic and contained ammonium. The study was conducted near the downgradient end of the ammonium zone, which was characterized by inversely trending vertical gradients of oxygen (270 to 0 microM) and ammonium (19 to 625 microM) and appeared to be a potentially active zone for nitrification. The tests were conducted by injecting a tracer solution (ambient ground water + added constituents) into selected locations within the gradients using multilevel samplers. After injection, the tracers moved by natural ground water flow and were sampled with time from the injection port. Rates of nitrification were determined from changes in nitrate and nitrite concentration relative to bromide. Initial tests were conducted with (15)N-enriched ammonium; subsequent tests examined the effect of adding ammonium, nitrite, or oxygen above background concentrations and of adding difluoromethane, a nitrification inhibitor. In situ net nitrate production exceeded net nitrite production by 3- to 6- fold and production rates of both decreased in the presence of difluoromethane. Nitrification rates were 0.02-0.28 mumol (L aquifer)(-1) h(-1) with in situ oxygen concentrations and up to 0.81 mumol (L aquifer)(-1) h(-1) with non-limiting substrate concentrations. Geochemical considerations indicate that the rates derived from single-well injection tests yielded overestimates of in situ rates, possibly because the injections promoted small-scale mixing within a transport-limited reaction zone. Nonetheless, these tests were useful for characterizing ground water nitrification in situ and for comparing potential rates of activity when the tracer cloud included non-limiting ammonium and oxygen concentrations.

Locomotor capacity of spinal cord in paraplegic patients.

The induction of complex bilateral leg muscle activation combined with coordinated stepping movements is demonstrated in patients with complete paraplegia. This was achieved by partially unloading patients who were on a moving treadmill. In comparison to healthy subjects, the paraplegic patients displayed a less dynamic mode of muscle activation. In all other respects leg muscle electromyographic activity was modulated in a similar manner to that in healthy subjects. However, the level of electromyographic activity in the gastrocnemius (the main antigravity muscle during gait) was considerably lower in the patients. During the course of a daily locomotor training program, the amplitude of gastrocnemius electromyographic activity increased significantly during the stance phase, while inappropriate tibialis anterior activation decreased. Incompletely paraplegic patients benefited from the training with respect to performance of unsupported stepping movements on solid ground. In about half of completely paraplegic patients with low muscle tone, no beneficial effect of the training was seen. This may be due to an inhibitory effect on spinal neuronal activity by drugs patients were taking (e.g., prazosin, clonidine, cannabinoids). In this study intrathecal application of clonidine drastically reduced, while epinephrine enhanced locomotor muscle electromyographic activity. The results of this study promise to be significant in the treatment of paraplegic patients.

Improvement of quality of life in women using a low-dose desogestrel-containing contraceptive: results of an observational clinical evaluation.

OBJECTIVE: To assess the influence of an oral contraceptive (OC) containing 20 microg ethinylestradiol and 150 microg desogestrel on quality of life and subjective symptoms. METHODS: In this multicenter observational evaluation performed in Germany, 3679 first-time OC users were included. They were treated by 623 physicians. The women completed quality of life questionnaires (Q-LES-Q) at baseline and after three treatment cycles. RESULTS: The mean age of users (+/- SD) was 22.5 +/- 7.1 years, with 47% of the women aged between 15 and 20 years. Half of the women reported skin problems at inclusion and, of these, 36% reported disappearance of the problems after three treatment cycles. Most women suffering from subjective symptoms (headache, nausea, nervousness, breast tenderness and depressive moods) at baseline reported improvements (57-71%) in their symptoms after using the OC for three cycles. Adverse events were reported by 4% of users; the most frequently reported were bleeding irregularities (1.7%). The total quality-of-life score and all its 13 individual items improved significantly (p < 0.0001), with the largest improvements in sex life and mood. Almost all (94%) women were either very satisfied or satisfied with the medication. CONCLUSION: The OC containing ethinylestradiol and desogestrel significantly improved the quality of life and subjective symptoms. The OC was well tolerated by first-time users.

Clinical significance of the tumour markers CA 125 II and CA 72-4 in ovarian carcinoma.

In a retrospective study we compared the usefulness of the tumour marker CA 72-4 with the established marker CA 125 II (both EIA on Cobas-Core, Hoffmann LaRoche, Basel Switzerland) at the time of primary diagnosis of ovarian carcinoma (n = 123) in order to discriminate between ovarian carcinomas of different histological type. We compared their diagnostic value, behaviour in follow-up care and evaluated possible combinations. Fixing specificity at 95% vs. benign gynaecological diseases (n = 37) as the clinically relevant reference group, we found cut-off values of 160 U/mL for CA 125 II and 3.0 U/mL for CA 72-4. On the basis of this specificity, we found comparable sensitivity for CA 125 II and CA 72-4 for all kinds of ovarian carcinoma at the time of primary diagnosis. With regard to histology, we found best sensitivity for CA 125 II in serous ovarian cancer and for CA 72-4 in mucinous ovarian cancer. Additional sensitivities were found in ovarian carcinoma in general but little in serous ones. No additive sensitivity was found in mucinous ovarian carcinomas with CA 72-4 as leading marker. In follow-up care, CA 72-4 was the leading marker in II cases and CA 125 II in 16, while in one case both markers were negative. In 6 cases the change of values reflecting clinical follow-up-care was within the so-called reference range. According to our results, at the time of primary diagnosis because of lack of histological findings the combined determination of CA 125 II and CA 72-4 can be recommended. In follow-up care and control of efficacy of therapy the preoperative positive or leading marker is generally sufficient. The determination of both markers in follow-up care is indicated only if they both are negative at primary diagnosis and until one of them becomes clearly positive.