P-027 which is the best method of testicular sperm retrieval for NOA? an answer from 1071 TESE cases in my clinics over 25 years

Study question

Which improves sperm recovery rate (SRR) for men with non-obstructive azoospermia (NOA), microdissection TESE (m-TESE) or conventional TESE (c-TESE)?

Summary answer

SRR of c-TESE vs. m-TESE for NOA was not significant. We need to develop a safer, less-invasive technique with fewer complications and higher SRR.

What is known already

m-TESE has been performed for men with NOA since Schlegel P’s report (Hum Reprod, 1999). Seminiferous tubules containing many developing germ cells were likely to be larger and more opaque and the ability to find spermatozoa increased from 45% (10/22) to 63% (17/27) after introduction of the microdissection technique. However, Jarvis S et al. (Turek PG group, 2019) reported that at least one site revealed mature sperm in 24 (29.3%) of 82 men with prior failed micro TESE procedures, and sperm were more likely to be found in the testis periphery rather than centrally with FNA mapping.

Study design, size, duration

TESE was performed in 1071 azoospermic patients in my clinics; c-TESE was performed for all azoospermic patients between 1996 and 2005 in Sendai; c-TESE for OA and m-TESE for NOA was performed from 2006 in Sendai, and from 2012 in Takanawa. The patients were divided into four groups; 1) FSH≦9.2mIU/ml, Testicular volume(TV)≧15/ml (OA), 2) FSH≦9.2mIU/ml, TV < 15ml, 3) FSH>9.2mIU/ml, TV≧15ml, 4) FSH>9.2mIU/ml, TV < 15ml (NOA).

Participants/materials, setting, methods

c-TESE was performed in 178 azoospermic men (50, 12, 7, 109, respectively) in 1996-2005. c-TESE was performed in 181 patients (131, 26, 15, 9, respectively) and m-TESE was performed in 541 patients (56, 33, 35, 416, respectively) in 2006 -2020. SRR, pregnancy rate (PR), and birth rate (BR) in 1996-2005 were compared with those in 2006-2020.

Main results and the role of chance

Statistical analysis was performed by chi-square analysis. SRR in c-TESE was 96.0% (48/50) in group 1 (OA) vs. 36.7% (40/109) in group 4 (NOA) in Sendai between 1996 and 2005 (P < 0.001).

SRR of c-TESE was 36.7% (40/109) in group 4 (NOA, in Sendai, 1996-2006), whereas SRR of m-TESE was 31.3% (130/416) in group 4 (NOA, in Sendai and Takanawa, 2006-2020). There was no significant difference (np).

Total SRR of conventional TESE for all azoospermic patients between 1996 and 2005 was 54.9% (96/175), whereas total SRR of c-TESE for OA and m-TESE for NOA between 2006 and 2020 was 51.7% (373/721). NOA rate 4) of azoospermic patients of 1996-2005 and that of 2006-2020 was 61.2% (109/178) and 58.9% (425/721), respectively. There was no significant difference (np).

PR was 37.4% (61/163) and BR was 31.9% (52/263) in c-TESE (1996-2005), PR was 39.6% (388/980), and BR was 27.6% (270//980) in both c-TESE and m-TESE (2006–2020). There was a significant difference in birth rate (P < 0.05).

In conclusion, SRR, PR, and BR were not improved even after m-TESE was performed. Considering the fact that m-TESE cannot find sperm thoroughly, adopting other techniques such as sperm fine-needle aspiration may be required.

Limitations, reasons for caution

Not applicable.

Wider implications of the findings

We could not show the effectiveness of m-TESE compared with c-TESE. However, the total volume of seminiferous tubules collected by c-TESE was the higher. The new one-step fine-needle aspiration has the potential to achieve higher sperm yield with fewer complications. Further advanced technology will hopefully improve the SRR in NOA.

Trial registration number

none

P-441 a study in status of use and live birth rates of cryopreserved oocyte for social reasons

Study question

What is status of use and live birth rates of cryopreservation oocyte for social reasons?

Summary answer

11.2% of the cryopreserved oocytes were warmed and transferred, and the oldest of the successful live birth was 39 years old.

What is known already

More people nowadays tend to delay marriage and childbearing due to the social circumstances. It is now gradually known that the pregnancy rate decreases with increasing age, since the donation of gametes from third parties is regulated by the Japanese society, oocyte cryopreservation for social reasons has been becoming common practice. However, not much is known about the subsequent pregnancy and childbirth. Therefore, we conducted a survey on the use and clinical outcomes of cryopreserved oocytes for social reasons in our clinic.

Study design, size, duration

This retrospective single-center study was conducted with a total of 285 women, 424 cycles from March 2014 to December 2019. A total of 2696 oocytes were cryopreserved by vitrification. Written informed consent was obtained from all women who participated in this study.

Participants/materials, setting, methods

Ovarian stimulation was performed mainly with GnRH antagonist protocol. An injection of 5000IU of HCG was administered when the diameter of dominant follicle reached 18mm. All oocytes were denuded enzymatically with 80 IU/ml hyaluronidase, followed by mechanical denudation. The oocytes were then evaluated at metaphase II by confirming the presence of the first polar body. Mature oocytes were cryopreserved by vitrification. The partner's sperm was injected into the vitrified-warmed oocytes.

Main results and the role of chance

The age groups in the first freezing cycle were 30-34 years (7.4%), 35-39 years (49.8%), 40-44 years (37.2%), and 45 years and older (5.6%), respectively. The mean number of OPU cycles was 1.1±0.4, 1.4±1.4, 1.5±1.1, and 1.7±1.7. The average number of retrieved oocytes was 9.5 ± 5.4, 7.3 ± 4.5, 5.6 ± 4.6, and 2.2 ± 2.2. The total number of cryopreserved oocytes was 10.4±5.9, 10.4±7.1, 8.8±6.8, and 3.3±3.4. Sixty-seven women had partners after oocyte cryopreservation, and 33 women (49.3%) had oocytes thawed. The mean age at oocytes freezing was 39.6±2.6 years, and the mean age at thawing was 42.2±2.5 years. The oocytes survival rates, fertilization rates, blastocyst rates and clinical pregnancy rates per embryo transferred of vitrified oocytes were 92.7% (328/354), 69.5% (228/328), 43.9% (87/198) and 31.1% (19/61), respectively. Of these, 15 women (45.5%) became pregnant with vitrified-warmed oocytes, and 10 (30.3%) had livebirth. 18 women did not become pregnant with vitrified-warmed oocytes. Subsequently, 3 of the 18 women then became pregnant in ART (5.6%), by IUI (5.6%), or spontaneously (5.6%), respectively.

Limitations, reasons for caution

Not applicable.

Wider implications of the findings

Of the 33 cases, 10 (30.3%) successfully gave birth, indicating the usefulness of oocyte cryopreservation for social reasons. However, considering that most of our patients were already around 40 years old, awareness of the benefits of oocytes cryopreservation at younger ages and education of reproductive health and rights is essential.

Trial registration number

none

Application of correlated component analysis to dynamic PET time-activity curves denoising

Positron emission tomography (PET) is a physiological, non-invasive imaging technique, which forms an essential part of nuclear medicine. The data obtained in a PET scan represent the concentration of an administered radiotracer in tissues over time. Quantitative analysis of PET data makes possible the assessments of in-vivo physiological processes. The Logan graphical analysis (LGA) is one of the methods that are used for quantitative analysis of PET data. LGA transforms PET data into a simple linear relationship. The slope of the LGA linear relationship is a physiological quantity denoting receptor availability. This quantity is termed distribution volume ratio (DVR). LGA-based estimates of the DVR are negatively affected by the noise in PET data -leading to the DVR being underestimated. A number of approaches proposed to address this issue have been observed to reduce the bias at the cost precision. An alternative regression method, least-squares cubic (LSC), was recently applied to estimate the DVR in order to reduce the bias. LSC was observed to reduce the bias in the LGA-based estimates. However, slight increases were also observed in the variance of the LSC-based estimates. This calls for methods to act against the variance in the LSC-based estimates. In this study, an alternative method is applied for tTAC denoising. This method is referred to as correlated component analysis (CorrCA). CorrCA transform the data by searching for dimensions of maximum correlation. This technique is closely related to other well-known methods such as principal component analysis and independent component analysis. In this study, the data were denoised by CorrCA (to act against the variance in the estimate) and the DVR was estimated by LSC, which provides for minimal bias. The resulting method LSC-CorrCA, gave less-biased estimated with increased precision. This was observed for both simulation results as well as for clinical data, both for ¹¹C Pittsburgh compound B. Simulation data revealed reduced variances in LCS-CorrCA-based estimates, and the clinical data showed improved contrast between gray and white matter regions.Clinical Relevance-Improved DVR estimates would ease the interpretation of medical images, which will in turn positively influence the clinical processes, from diagnosis to treatment and follow-ups.

[Evaluation of physical activity using smartphones and wearable devices in healthcare: Current situation and future perspectives]

Abstract　With the growing popularity of mobile health (mHealth) devices, including smartphones and wearable devices, information and communications technology has gained high importance in healthcare settings. This study aimed to summarize the current trends in physical activity research wherein mHealth devices are used and provide perspectives for future research. Until recently, questionnaire surveys were primarily used to evaluate physical activity. While questionnaire surveys are effective for subjective evaluation, the use of mHealth devices enables large-scale, real-time, objective evaluation of physical activity. In addition, mHealth devices automatically collect and aggregate data. This allows researchers to perform retrospective analysis of a wide range of indicators of physical activity and health. Particularly, the use of smartphones is highly likely to contribute to large-scale monitoring and health interventions because of their ubiquity. Even though there are fewer users of wearable devices (wrist-worn devices) than those of smartphones, using wearable devices allows for the evaluation of 24-hour movement patterns. The use of wearable devices helps perform further precise analysis that focuses not only on the total amount of physical activity but also on the quality, including measures of intensity, duration, frequency, type, and time. Moreover, some wrist-worn devices measure physiological information such as heart rate and may also provide location information. Combining such data with information from an accelerometer associated with a device may allow for further specific and detailed evaluation of physical activity. The validity of physical activity assessment using major mHealth devices has been confirmed in several studies and is comparable to that of pedometers and accelerometers developed for research purposes. Evaluation of physical activity using mHealth devices involves issues related to the representativeness of the target population and continuity of data, as well as the need for ethical considerations based on privacy policies. While mHealth devices may be used by individuals as a health management tool, it is also expected that the evaluation of physical activity using mHealth devices will be performed in various settings such as epidemiological and clinical studies on physical activity, as well as community services wherein indicators of physical activity are used.

Improving contrast between gray and white matter of Logan graphical analysis' parametric images in positron emission tomography through least-squares cubic regression and principal component analysis

Logan graphical analysis (LGA) is a method for in vivo quantification of tracer kinetics in positron emission tomography (PET). The shortcoming of LGA is the presence of a negative bias in the estimated parameters for noisy data. Various approaches have been proposed to address this issue. We recently applied an alternative regression method called least-squares cubic (LSC), which considers the errors in both the predictor and response variables to estimate the LGA slope. LSC reduced the bias in non-displaceable binding potential estimates while causing slight increases in the variance. In this study, we combined LSC with a principal component analysis (PCA) denoising technique to counteract the effects of variance on parametric image quality, which was assessed in terms of the contrast between gray and white matter. Tissue time-activity curves were denoised through PCA, prior to estimating the regression parameters using LSC. We refer to this approach as LSC-PCA. LSC-PCA was assessed against OLS-PCA (PCA with ordinary least-squares (OLS)), LSC, and conventional OLS-based LGA. Comparisons were made for simulated¹¹C-carfentanil and¹¹C Pittsburgh compound B (¹¹C-PiB) data, and clinical¹¹C-PiB PET images. PCA-based methods were compared over a range of principal components, varied by the percentage variance they account for in the data. The results showed reduced variances in distribution volume ratio estimates in the simulations for LSC-PCA compared to LSC, and lower bias compared to OLS-PCA and OLS. Contrasts were not significantly improved in clinical data, but they showed a significant improvement in simulation data |indicating a potential advantage of LSC-PCA over OLS-PCA. The effects of bias reintroduction when many principal components are used were also observed in OLS-PCA clinical images. We therefore encourage the use of LSC-PCA. LSC-PCA can allow the use of many principal components with minimal risk of bias, thereby strengthening the interpretation of PET parametric images.

Correlation of left atrial strain with left ventricular end-diastolic pressure in patients with coronary artery disease and preserved left ventricular ejection faction

Funding Acknowledgements

Type of funding sources: None.

Background

Elevated left ventricular (LV) filling pressures are the main physiologic consequence of LV diastolic dysfunction. Left atrial (LA) strain was recently found useful to predict elevated LV filling pressures noninvasively. However, there are few reports on the role of LA strain when predicting LV filling pressure in patients with coronary artery disease (CAD). The aim of this study was to explore the correlation between LA strain and LV end-diastolic pressure (LVEDP) in patients with CAD and preserved LV ejection fraction.

Methods

Fifty-four patients with stable CAD were enrolled. Global atrial longitudinal strain was measured by averaging all atrial segments. Resorvoir (S-LAs), conduit (S-LAe), and contractile (S-LAa) phase strain were obtained. LVEDP was invasively obtained by left heart catheterization.

Results

Patients were divided into two groups: elevated LVEDP group (LVEDP > 15mmHg group: n = 23) and normal LVEDP group (LVEDP ≤ 15mmHg group: n = 31). Elevated LVEDP group showed significantly decreased S-LAs and S-LAa (S-LAs: 21.3 ± 7.2% vs. 27.5 ± 7.8%, p < 0.005; S-LAa: 9.7 ± 3.3% vs. 14.6 ± 3.4%, p < 0.0001). However, E/Ea and S-LAe were not significantly different between the two groups. LVEDP significantly correlated with S-LAa (r=-0.596, p < 0.0001) and S-LAs (r=-0.431, p < 0.001). Receiver operating characteristics curve analysis showed that S-LAa could predict elevated LVEDP (AUC = 0.84) and a cut-off value of S-LAa < 11.6% was able to most accurately identify patients with elevated LVEDP.

Conclusions

LA strain, especially S-LAa, provided additional diagnostic value for the noninvasive assessment of LV filling pressure in CAD patients with preserved LV ejection fraction.

Effects of PCSK9 inhibitor on adverse limb outcomes in patients with critical limb ischemia

Background

The proprotein convertase subtilisin/kexin type 9 inhibitor (PCSK9-I), evolocumab, reduced the risk of cardiovascular event in patients with peripheral artery disease in FOURIER trial. However, the effects of evolocumab on favorable limb outcomes in patients with critical limb ischemia (CLI) is still unclear.

Purpose

The aim of this study was to evaluate the impacts of evolocumab on favorable limb outcomes and lipid profile in patients with CLI.

Methods

This was a single center, prospective observational study. A total of 39 patients with CLI were enrolled between November 2016 to May 2019. The subjects were divided into 2 groups based on evolocumab administration: evolocumab-treated group: E group (mean 69.4±11.7 years, n=14) and evolocumab non-treated group: Non-E group (mean 74.0±8.8 years, n=25). Baseline characteristics were assessed at admission. Lipid profile was evaluated at admission, 1, 3, 6, 12 and 18 months. The primary outcome was defined 18-month amputation-free survival (AFS). The secondary outcomes were defined 18-month overall survival (OS) and wound-free limb salvage. Mean follow-up period was 18±11 months.

Results

The patients in E group had greater reduction in levels of LDL cholesterol and non-HDL cholesterol than those in Non-E group over time. The reduction in MDA-LDL level was maintained at 1, 3, 6, 12 months, respectively. The 18-month AFS rate in the E-group was significantly higher than those in the Non-E group (log-rank p=0.02). The patients receiving evolocumab had a lower hazard regarding AFS (hazard ratio, 0.12; 95% confidence interval, 0.02–0.94; P=0.043) and a higher proportion of wound-free limb salvage at 12 months (E group [92%] vs Non-E group [57%], P=0.034) and 18 months (92% vs 52%, P=0.03). Otherwise, evolocumab administration was not associated with 18-month OS (log-rank p=0.053).

Conclusions

Evolocumab administration may be associated with the favorable outcome of 18-month AFS in the patients with CLI. Additionally, long-term administration of evolocumab over 12 months may improve wound-free limb salvage.

Effects of evolocumab on limb outcomes

Funding Acknowledgement

Type of funding source: None

Changes in Autonomic Nervous System and Axillary Temperature Caused by Electric Potential Therapy

This paper describes two experiments conducted to investigate changes in the autonomic nervous system and axillary temperature caused by electric potential therapy. The former was investigated using a frequency analysis of successive heartbeats (RR intervals) and cortisol in saliva. The experimental results on the RR intervals suggest no significant change in the autonomic nervous system, but those on the saliva cortisol indicate a change in the system during the therapy. The axillary temperature showed a significant increase. The results on the autonomic nervous system seem inconsistent, and these results as well as future directions were discussed.

A strategy to account for noise in the X-variable to reduce underestimation in Logan graphical analysis for quantifying receptor density in positron emission tomography

Background

The Logan graphical analysis (LGA) algorithm is widely used to quantify receptor density for parametric imaging in positron emission tomography (PET). Estimating receptor density, in terms of the non-displaceable binding potential (BP_ND), from the LGA using the ordinary least-squares (OLS) method has been found to be negatively biased owing to noise in PET data. This is because OLS does not consider errors in the X-variable (predictor variable). Existing bias reduction methods can either only reduce the bias slightly or reduce the bias accompanied by increased variation in the estimates. In this study, we addressed the bias reduction problem by applying a different regression method.

Methods

We employed least-squares cubic (LSC) linear regression, which accounts for errors in both variables as well as the correlation of these errors. Noise-free PET data were simulated, for ¹¹C-carfentanil kinetics, with known BP_ND values. Statistical noise was added to these data and the BP_NDs were re-estimated from the noisy data by three methods, conventional LGA, multilinear reference tissue model 2 (MRTM2), and LSC-based LGA; the results were compared. The three methods were also compared in terms of beta amyloid (A β) quantification of ¹¹C-Pittsburgh compound B brain PET data for two patients with Alzheimer’s disease and differing A β depositions.

Results

Amongst the three methods, for both synthetic and actual data, LSC was the least biased, followed by MRTM2, and then the conventional LGA, which was the most biased. Variations in the LSC estimates were smaller than those in the MRTM2 estimates. LSC also required a shorter computational time than MRTM2.

Conclusions

The results suggest that LSC provides a better trade-off between the bias and variability than the other two methods. In particular, LSC performed better than MRTM2 in all aspects; bias, variability, and computational time. This makes LSC a promising method for BP_ND parametric imaging in PET studies.

P6339Sequential organ failure assessment score on admission predicts long-time mortality of the patients with acute heart failure

Background

Despite the remarkable advances in the treatment options of acute heart failure (HF), prognosis assessment remains an ongoing challenge. Previous studies revealed only a moderate accuracy of models predicting mortality. Sequential Organ Failure Assessment (SOFA) Score are widely used in the intensive care unit (ICU) to predict outcome and predicted higher long-time mortality in unselected patients in cardiac ICU. In addition, the American Heart Association Get With the Guidelines–Heart Failure (GWTG-HF) risk score allows for risk stratification of 30-day outcome for patients hospitalized with HF. The purpose of this study was to evaluate whether SOFA score on admission is useful for long-time mortality prediction in acute HF patients and also to assess the discriminative performance as compared with GWTG-HF risk score.

Methods

This was a single-centre, retrospective cohort study. Between January 2007 and December 2016, we screened eligible 661 consecutive patients with acute HF administered at our hospital. SOFA score on admission of 294 patients was able to calculate retrospectively. We enrolled 269 patients who could complete follow up evaluation for more than 1 year. Endpoint was all-cause mortality after admission. Additive information of SOFA score was evaluated by area under the curve (AUC), net reclassification improvement (NRI), integrated discrimination improvement (IDI) and decision curve analysis (DCA).

Results

The 269 patients were included in this study (78.5±10.9 years; 136 men; left ventricular ejection fraction [EF], 49.8±16.6%) during a mean follow-up of 32.1±22.3 months. Patients with all-cause death had higher SOFA score (4.2±2.3 versus 2.8±1.8, p<0.001; AUC, 0.689) and GWTG-HF risk score (44.0±7.6 versus 38.1±7.9, P<0.001, AUC, 0.692).

Kaplan-Meier survival analysis demonstrated higher SOFA scores (P<0.001) and GWTG-HF risk scores (P<0.001) appears to be related to increase probabilities of all cause death. A multivariate Cox proportional hazard model were made with adjustment for SOFA score, GWTG-HF risk score, age, gender and ejection fraction. As a result, SOFA score (hazard ratio [HR] 1.227; 95% confidence interval [CI], 1.130 to 1.326; P<0.001), GWTG-HF (HR, 1.054; 95% CI, 1.029 to 1.078; P<0.001) and age (HR, 1.069; 95% CI 1.048 to 1.092; P<0.001) were independent predictors of all cause death and HR of SOFA score was the highest in these parameters. Incorporating SOFA score into GWTG-HF score yielded a significant NRI (0.528 (95% CI 0.291 to 0.765) and IDI (0.046 (95% CI 0.020 to 0.072). In DCA, compared with the reference model, the net benefit for SOFA score model was greater across the range of threshold probabilities.

Conclusions

The SOFA score, simple and validated mortality risk score can predict long-term all-cause mortality in patients with acute HF. Discriminative performance metrics such as NRI, IDI and DCA were improved on incorporation of the SOFA score for prediction of mortality.

Machine Learning Approach for Predicting New Uses of Existing Drugs and Evaluation of Their Reliabilities

In this chapter, a new method to evaluate the reliability of predicting new uses of existing drugs was proposed. The prediction was performed with a support vector machine (SVM) using various data. Because the reliability of prediction could not be evaluated based on the output of an SVM, which was binary, the proposed method evaluated the reliability as a product of a distance from the separating hyperplane of the SVM and a similarity between the disease targeted by the drug and a candidate disease. A validation using real data revealed that the performance of the proposed method was promising.

Information Encoding Methods for a Balance Assist Device Using Vibrotactile Feedback

This study investigates the applicability of information encoding methods for a balance assist device using vibrotactile feedback. In the device, two motors were employed to provide information on the model's sway angle in each of the forward and backward directions. In the experiment involving ten healthy volunteers, two encoding modes with different vibration patterns were compared using an equivalent body model. The influence of proficiency level was also investigated. The results indicated that a simple encoding method outperformed a complex one even after the proficiency level was improved. Further analyses on the input and output of the model indicated the necessity of a time domain signal for encoding feedback information with the complex encoding methodology.

Preliminary evidence supports circulating microRNAs as prognostic biomarkers for type 2 diabetes

Background

Circulating microRNAs are emerging as potential prognostic biomarkers for the development of type 2 diabetes. However, microRNAs are also associated with complications from impaired glucose metabolism (e.g. endothelial cell function). Prior studies have not evaluated for associations between trajectories of circulating microRNAs with trajectories of fasting blood glucose over time and the responses to behavioral interventions to reduce risk. This study performed longitudinal assessment of microRNAs and fasting blood glucose and identified relationships between microRNAs and behavioral risk reduction interventions.

Methods

MicroRNAs (n = 353) were measured in subsets (n = 10, n = 8) of participants from previously completed clinical trials that studied behavioral risk reduction interventions. Fasting blood glucose trajectories were associated with changes in 45 microRNAs over 12 months.

Results

Following a 3‐month physical activity and dietary intervention compared with baseline, 13 microRNAs were differentially expressed. Seven microRNAs (i.e. miR‐106b, miR‐20b, miR‐363, miR‐486, miR‐532, miR‐92a and miR‐93) were commonly identified between the two analyses.

Conclusions

Further studies are needed to determine which microRNAs are prognostic biomarkers of risk for type 2 diabetes versus consequences of impaired glucose metabolism. Additional future directions of this research are to differentiate whether microRNAs are prognostic and/or diagnostic biomarkers for risk for type 2 diabetes and predictive biomarkers of responses to risk reduction interventions.

Downregulation of Plasma miR-215 in Chronic Myeloid Leukemia Patients with Successful Discontinuation of Imatinib

Approximately 40% of chronic myeloid leukemia (CML) patients who discontinue imatinib (IM) therapy maintain undetectable minimal residual disease (UMRD) for more than one year (stopping IM (STOP-IM)). To determine a possible biomarker for STOP-IM CML, we examined plasma miRNA expression in CML patients who were able to discontinue IM. We first screened candidate miRNAs in unselected STOP-IM patients, who had sustained UMRD after discontinuing IM for more than six months, in comparison with healthy volunteers, by using a TaqMan low-density array for plasma or exosomes. Exosomal miR-215 and plasma miR-215 were downregulated in the STOP-IM group compared to the control, indicating that the biological relevance of the plasma miR-215 level is equivalent to that of the exosomal level. Next, we performed real-time quantitative RT-PCR in 20 STOP-IM patients, 32 patients with UMRD on continued IM therapy (IM group) and 28 healthy volunteers. The plasma miRNA-215 level was significantly downregulated in the STOP-IM group (p < 0.0001); we determined the cut-off level and divided the IM group patients into two groups according to whether the plasma miR-215 was downregulated or not. The IM group patients with a low plasma miR-215 level had a significantly higher total IM intake, compared to the patients with elevated miR-215 levels (p = 0.0229). Functional annotation of miR-215 target genes estimated by the Database for Annotation, Visualization and Integrated Discovery (DAVID) bioinformatic tools involved cell cycle, mitosis, DNA repair and cell cycle checkpoint. Our study suggests a possible role of miR-215 in successful IM discontinuation.

Phosphocreatine resynthesis during recovery in different muscles of the exercising leg by 31P-MRS

To investigate the high-energy phosphate metabolism by (31) P-nuclear magnetic resonance spectroscopy during off-transition of exercise in different muscle groups, such as calf muscles and biceps femoris muscles, seven male long-distance runners (LDR) and nine untrained males (UT) performed both submaximal constant and incremental exercises. The relative exercise intensity was set at 60% of the maximal work rate (60%W max) during both knee flexion and plantar flexion submaximal constant load exercises. The relative areas under the inorganic phosphate (Pi ) and phosphocreatine (PCr) peaks were determined. During the 5-min recovery following the 60%W max, the time constant for the PCr off-kinetics was significantly faster in the plantar flexion (LDR: 17.3 ± 3.6 s, UT: 26.7 ± 6.7 s) than in the knee flexion (LDR: 29.7 ± 4.7 s, UT: 42.7 ± 2.8 s, P < 0.05). In addition, a significantly faster PCr off-kinetics was observed in LDR than in UT for both exercises. The ratio of Pi to PCr (Pi /PCr) during exercise was significantly lower during the plantar flexion than during the knee flexion (P < 0.01). These findings indicated that the calf muscles had relatively higher potential for oxidative capacity than that of biceps femoris muscles with an association of training status.

Development of a compact wireless Laplacian electrode module for electromyograms and its human interface applications

In this study, we developed a compact wireless Laplacian electrode module for electromyograms (EMGs). One of the advantages of the Laplacian electrode configuration is that EMGs obtained with it are expected to be sensitive to the firing of the muscle directly beneath the measurement site. The performance of the developed electrode module was investigated in two human interface applications: character-input interface and detection of finger movement during finger Braille typing. In the former application, the electrode module was combined with an EMG-mouse click converter circuit. In the latter, four electrode modules were used for detection of finger movements during finger Braille typing. Investigation on the character-input interface indicated that characters could be input stably by contraction of (a) the masseter, (b) trapezius, (c) anterior tibialis and (d) flexor carpi ulnaris muscles. This wide applicability is desirable when the interface is applied to persons with physical disabilities because the disability differs one to another. The investigation also demonstrated that the electrode module can work properly without any skin preparation. Finger movement detection experiments showed that each finger movement was more clearly detectable when comparing to EMGs recorded with conventional electrodes, suggesting that the Laplacian electrode module is more suitable for detecting the timing of finger movement during typing. This could be because the Laplacian configuration enables us to record EMGs just beneath the electrode. These results demonstrate the advantages of the Laplacian electrode module.

A two-step drug repositioning method based on a protein-protein interaction network of genes shared by two diseases and the similarity of drugs

The present study proposed a two-step drug repositioning method based on a protein-protein interaction (PPI) network of two diseases and the similarity of the drugs prescribed for one of the two. In the proposed method, first, lists of disease related genes were obtained from a meta-database called Genotator. Then genes shared by a pair of diseases were sought. At the first step of the method, if a drug having its target(s) in the PPI network, the drug was deemed a repositioning candidate. Because targets of many drugs are still unknown, the similarities between the prescribed drugs for a specific disease were used to infer repositioning candidates at the second step. As a first attempt, we applied the proposed method to four different types of diseases: hypertension, diabetes mellitus, Crohn disease, and autism. Some repositioning candidates were found both at the first and second steps.

Systemes analysis of interactions between microRNAs and genes in hepatocellular carcinoma

MicroRNAs (miRNAs) are short noncoding RNAs and can regulate gene expression at the transcriptional and/or translational levels. There is mounting evidence that miRNAs play an important role in the control of the dynamics of localized gene expression. Expression profiling of miRNA in various cancers revealed that miRNA profiles could discriminate malignancies from their counter parts. In this study, to investigate the localized effect of miRNA in cancer, we analyzed gene and miRNA expressions in hepatocellular carcinoma (HCC) and surrounding nontumor tissues. Based on gene expression levels around miRNAs, we investigated how many miRNAs correlated positively/negatively in expression with genes in the vicinity. Next, the Pearson correlation coefficients were compared between the HCC and nontumor tissues. The results imply that the relationship between the intronic miRNAs and their host genes was altered in HCC, and that feedback loops including the host gene, intronic miRNA, target genes might be formed in HCC.

Loss of NKX3-1 as a potential marker for an increased risk of occult lymph node metastasis and poor prognosis in oral squamous cell carcinoma

The prognosis of oral squamous cell carcinoma (OSCC) is significantly dependent on the existence of cervical lymph node metastasis (LNM), with the overall survival rate being much lower in patients with LNM. Primary causes and molecular mechanisms of LNM are still largely unclear. We hypothesized that factors related with cancer progress and/or prognosis in OSCC are revealed by genome-wide investigation of DNA copy number aberrations (CNAs). In order to find biomarkers for occult LNM of OSCC, we comprehensively investigated genomic DNAs from 60 OSCC patients using Affymetrix mapping arrays and statistically analyzed correlations between CNAs of genes and the presence of occult LNM in the patients. The genome-wide CNA study indicated significant correlations between the presence of occult LNM and CNAs of certain genes. Through a literature survey, we narrowed down the candidates and focused on loss of NKX3-1, which is a homeodomain-containing transcription factor. NKX3-1 is known as a tumor suppressor gene in prostate cancer but has never been reported in OSCC. Quantitative RT-PCR and immunohistochemistry (IHC) analyses also showed significantly lower expression of NKX3-1 in the cases with occult LNM, which was further validated by IHC analysis in independent cases. The survival analyses indicated that NKX3-1 loss is a significant risk factor to decrease the disease-free survival (DFS) and the overall survival (OS) rates. This is the first time that the significant association of NKX3-1 loss and occult LNM was indicated in OSCC. The present results suggest that loss of NKX3-1 may be a potential biomarker for occult LNM of OSCC.

Genome-wide integrative analysis revealed a correlation between lengths of copy number segments and corresponding gene expression profile

Microarray analysis has been applied to comprehensively reveal the abnormalities of DNA copy number (CN) and gene expression in human cancer research during the last decade. These analyses have individually contributed to identify the genes associated with carcinogenesis, progression, metastasis of tumor cells and poor prognosis of cancer patients. However, it is known that the correlation between profiles of CN and gene expression does not highly correlate. Factors which determine the degree of correlation remain largely unexplained. To investigate one such factor, we performed trend analyses between the lengths of CN segments and corresponding gene expression profiles from microarray data in hepatocellular carcinoma (HCC) and colorectal carcinoma (CRC). Significant correlations were observed in CN gain of HCC and CRC (p<0.05). The trend of the CN loss showed a significant correlation in HCC although there was no correlation between the length of CN loss segments and gene expression in CRC. Our findings suggest that the influence of CN on gene expression highly depends on the length of CN region, especially in the case of CN gain. To the best of our knowledge, this is the first study describing the correlation between lengths of CNA segments and expression profiles of corresponding genes.

Time course of the recovery of three-dimensional eye position in patients with acute cerebellitis

Listing's plane is a construction derived from eye position and reflects gravitational orientation. The cerebellum plays a key role in orienting and integrating sensory input concerning gravity from visual, vestibular and proprioceptive apparatuses. This suggests that the thickness of Listing's plane could serve as a novel parameter for evaluating the accuracy of the constructed gravity-oriented internal model. We report a case with acute cerebellitis along with data on Listing's plane, calculated from consecutive infrared video-oculogram recordings. We found thickening of Listing's plane at the early stage of the disease, and a gradual reduction of the thickness into normal range in parallel with the recovery of the patient's posture and gate. Notably, clinical improvement of the patient's posture was delayed relative to the normalization of the thickness of Listing's plane. The thickness of Listing's plane reflects the stability of the cerebellar-mediated cognitive gravitational reference frame. This thickness value could serve as a parameter to quantitatively evaluate the function of the constructed internal model. Recovery from cerebellar ataxia (manifested as normalization of the thickness of Listing's plane) was followed by recovery of muscular strength lost during the period the patient was by his disease forced to assume a lying position.

Adaptive thresholds to detect differentially expressed genes in microarray data

To detect changes in gene expression data from microarrays, a fixed threshold for fold difference is used widely. However, it is not always guaranteed that a threshold value which is appropriate for highly expressed genes is suitable for lowly expressed genes. In this study, aiming at detecting truly differentially expressed genes from a wide expression range, we proposed an adaptive threshold method (AT). The adaptive thresholds, which have different values for different expression levels, are calculated based on two measurements under the same condition. The sensitivity, specificity and false discovery rate (FDR) of AT were investigated by simulations. The sensitivity and specificity under various noise conditions were greater than 89.7% and 99.32%, respectively. The FDR was smaller than 0.27. These results demonstrated the reliability of the method.

Postural stability during visual stimulation and the contribution from the vestibular apparatus

CONCLUSION

When combined with vestibular dysfunction, visual flow can exacerbate reductions in postural stability. This effect may be one of the mechanisms underlying visual vertigo, which can be evaluated using frequency analysis of body sway elicited by optokinetic stimulation (OKS).

OBJECTIVE

To clarify the interaction between the postural responses to visual flow and to input from the vestibular apparatus as a mediator of visual vertigo.

METHODS

Horizontal and vertical OKS with a stable fixation target were presented to 14 healthy subjects and 38 peripheral vestibular patients standing in a Romberg's posture, and the center of standing pressure was monitored using a force platform. The direction and amplitude of induced body sway were analyzed, along with the power spectra of the body mass fluctuations.

RESULTS

Each directional optokinetic stimulus induced body sway that would compensate for the virtual inclination of the subject's gravitational reference frame. However, the amplitude of this body sway was not increased by vestibular dysfunction. Healthy subjects showed increased stability in response to downward OKS and decreased stability in response to upward OKS, whereas no specific changes were seen in response to horizontal OKS. This stability was greatly diminished in patients with vestibular dysfunction subjected to the same directional OKS.

Adaptive threshold for detecting differentially expressed genes in microarray data - a simulation study to investigate its performance

To detect changes in gene expression data from DNA microarrays, a fixed threshold value is used in various studies. However, it is not always guaranteed that a threshold value which is appropriate for highly expressed genes is suitable for genes with low expression. To address this issue, we have proposed adaptive threshold, which has different values for different expression levels. In this study, the performance of the adaptive threshold method was investigated through simulations. The sensitivity in various noise conditions was in a range between 72.7 and 100% while the specificity was better than 99% for all noise conditions. These results demonstrated the good performance of the proposed method.

Influence of work rate on dynamics of O2 uptake under hypoxic conditions in humans

AIM

It was the purpose of the investigation to determine whether an altered work rate could influence the oxygen uptake (V.O(2)) and heart rate (HR) dynamics at hypoxia and normoxia.

METHODS

Ten males performed a cycle exercise with 2 repetitions of 6 min each at a constant work load while breathing one of two inspiratory O(2) fractions (FIO(2)): 0.12 (moderate hypoxia) and 0.21 (normoxia). Each test began with unloaded pedaling. This was followed by three constant loads, which were 40%, 60%, and 80% of the subject's gas exchange threshold (GET) in hypoxia (F(I)O(2) = 0.12), with the 80% GET load repeated under normoxia (room air). V.O(2) was measured on a breath-by-breath basis and beat-by-beat HR via ECG, and the half time (t1/2) of each parameter was established, following interpolation data.

RESULTS

There were no remarkable differences in t1/2 V.O(2) dynamics among the 40%, 60% and 80% GET; however, the differences became significant at hypoxia compared with normoxia. The HR dynamics were significantly faster in normoxia compared with hypoxia, independent of work rates. During steady-state exercise, the alterations in HR and cardiac output (Q) using the acetylene rebreathing method depended on increases in the work rate, and a significantly increase in at 80% GET was observed when compared with normoxia. Increases of stroke volume (SV) were unaffected by altered work rates and inspired O(2) concentrations. The arteriovenous oxygen difference (Ca-vO(2)) at a steady-state of exercise increased proportionally with the work rate under hypoxia, and a much greater Ca-vO(2) was observed during normoxic exercise than under hypoxia.

CONCLUSION

These results seem to suggest that in humans, O(2) uptake dynamics are affected by lower O(2), not by changing work rates at hypoxia, to which the interaction between lower O(2) utilization in exercising muscles and hypoxic-induced greater blood flow can be attributed.

Clock gene dysfunction in patients with obstructive sleep apnoea syndrome

Clock genes regulate mammalian circadian rhythms, and dysfunction of clock genes can contribute to various disorders. To investigate whether obstructive sleep apnoea syndrome (OSAS) influences clock gene function, the present authors examined Period1 (Per1) mRNA expression in vitro and in vivo. In eight healthy subjects and eight OSAS patients, plasma noradrenaline, serum interleukin (IL)-6, high-sensitivity C-reactive protein (hsCRP) and Per1 mRNA expression in peripheral whole blood were measured. Expression of Per1 mRNA in cultured cells was examined under IL-6 or noradrenaline stimulation in vitro. After noradrenaline was administered to mice in vivo, Per1 mRNA expression in the brain was examined. The concentrations of serum IL-6, hsCRP and plasma noradrenaline were elevated in OSAS patients, but improved by continuous positive airway pressure (CPAP) therapy. Per1 mRNA expression in the peripheral blood significantly decreased at 02:00 h by CPAP in OSAS patients. Stimulation with IL-6 did not directly induce Per1 mRNA in vitro. Administration of noradrenaline induced Per1 mRNA in the cerebral cortex of mice in vivo. The current study revealed that obstructive sleep apnoea syndrome caused clock gene dysfunction, and continuous positive airway pressure helped to improve it. Sympathetic activation and elevation of the plasma noradrenaline concentration in obstructive sleep apnoea syndrome may be one of the factors involved in disorders of Period1 mRNA expression.

Adaptive threshold to detect biologically meaningful changes in microarray data

To detect changes in gene expression data from DNA microarrays, a fixed threshold value is widely used. However, it is not always guaranteed that a threshold value which is appropriate for highly expressed genes is suitable for genes with low expression. In this study, aiming at detecting biologically meaningful changes from a wide range of expression levels, we proposed an adaptive threshold method. The performance of the proposed method was investigated using publicly available expression data.

Stability of the human upright stance depending on the frequency of external disturbances

During an upright stance of humans, it is usually assumed that a stiffer ankle joint contributes to stabilize the stance. To show that under certain conditions a stiffer ankle joint can reduce the stability, the frequency responses of the moment and the angle of the ankle joint against external disturbances caused by random horizontal translations of the support surface were evaluated in ten healthy adult subjects by varying the difficulty of the task at four levels. When it was difficult to keep the upright stance, the subject tended to make the ankle joint stiffer. The transfer function relating the external disturbance moment to the ankle joint moment showed a larger gain in the high frequency range (>0.3 Hz) compared with the gains obtained under easier conditions. A simulation analysis based on a simple inverted pendulum model also reproduced this tendency. These results indicate that the stiffer ankle joint and the resulting higher ankle moment for high frequency external disturbances enhance the possibility that the center of pressure exceeds the limit arising from the size of the feet and can make the upright stance unstable.

Range of motion measurement of an artificial hip joint using CT images

Total hip arthroplasty (THA) is one of the most effective treatments for osteoarthritis and rheumatoid arthritis. Dislocation of the femoral head from the acetabular socket is a major problem of THA. To prevent dislocation, it is important to know the range of motion (ROM) after THA. Although various studies on the ROM were carried out, there exist only a few reports on ROM evaluation in individual patients. This is because in clinical cases, bone-to-bone and bone-to-component contacts must be considered besides the impingement of components. In this study, a new method for evaluating ROM of internal/external rotation, which takes into account all combinations of contacts between the bones and components, was proposed. A computer simulation demonstrated that the RMS error of the proposed method was approximately 3 degrees . The method was applied to 33 THAs under various conditions of flexion and adduction angles. The method was able to detect any type of impingement. The evaluated ROM was in good agreement with that measured during the THA operation (correlation coefficient = 0.91).

Sensory stimulation triggers spindles during sleep stage 2

STUDY OBJECTIVES

Toward understanding the function of sleep spindle, we examined whether sensory stimulation triggers sleep spindles.

PARTICIPANTS

Eleven normal subjects participated in the experiments.

INTERVENTION

The subjects had a nap in the afternoon, and sensory stimulation was applied during sleep stage 2.

MEASUREMENTS

21-channel EEG was recorded during the 2-3 hour experiment carried out between 13:00 and 16:00. Somatosensory, auditory, or visual stimulation was performed over a 5-minute period during stage 2. The frequency and duration of spindles were compared in 2 different segments of 5 minutes, with and without sensory stimulation. The latency from the onset of a sensory stimulus to the succeeding spindle was also analyzed. To estimate the active brain regions during a spindle, the EEG recordings were modeled with a single equivalent moving dipole (SEMD) model.

RESULTS

In the period with stimulation, spindle frequency and duration increased compared with the period without stimulation. Statistical tests revealed that with stimulation, the interval between 2 consecutive spindles was significantly shorter (p < 0.05, regardless of the modality) and that the duration of the spindles was significantly longer with stimulation (p < 0.05, regardless of the modality). The latency was approximately 2 s. During a spindle after somatosensory stimulation brain activities were observed near the somatosensory area, while with auditory stimulation active regions were observed near the auditory cortex.

CONCLUSIONS

A sensory stimulus appeared to trigger a sleep spindle during sleep stage 2. SEMD trajectories suggest that active brain regions during spindle are different according to the modality of the preceding stimulus.

Evidence of spatially bound gene regulation in Mus musculus: decreased gene expression proximal to microRNA genomic location

The extent, spatially and in time, of the phenomenon of localized decreased expression in the chromosomal vicinity of microRNA (miRNA) previously described in Caenorhabditis elegans is reproduced in Mus musculus across a wide range of tissues in several independent experiments. Computationally predicted miRNA targets are enriched in the vicinity of miRNAs, and transcription factors are identified as the class of genes that systematically exhibit this localized decrease. Also, those mRNA with AT-rich UTRs, particularly those that are not in the vicinity of CpG islands, most often exhibit this localized decrease. This localization broadens with the shift from developing to mature/differentiated tissues and suggests a developmentally controlled and spatially bound regulation.

Cross-coupling in a body-translating reaction: interaural optokinetic stimulation reflects a gravitational cue

CONCLUSION

The velocity storage integrator does not play a dominant role in the postural response to vertical visual cues; more likely, retinal slip provides the main driving force. By contrast, sideways eye movement can drive the velocity storage integrator and preserve a gravitational cue, which would be observed as a cross-coupling effect on the postural response.

OBJECTIVES

To investigate the mechanism by which optokinetic stimulation causes the body to translate and to determine whether the optokinetic information is accompanied by a gravitational cue, which would appear as a cross-coupling effect.

MATERIALS AND METHODS

Directionally diverse optokinetic stimuli were presented to seven healthy subjects, with and without a fixation target, and the body-translation of the subjects was recorded.

RESULTS

Horizontal optokinetic stimulation with a fixation target caused the body to translate in the same direction as the optic flow. Upward or downward vertical optokinetic stimulation caused the body to translate backward or forward, respectively, only when a fixation target was present. When the subject's interaural axis was parallel to the optokinetic flow, diagonal optokinetic stimulation in the absence of a fixation target elicited responses in the pitch plane similar to those elicited by vertical stimulation in the presence of a fixation target.

Applicability of the Single Equivalent Moving Dipole Model in an Infinite Homogeneous Medium to Identify Cardiac Electrical Sources: A Computer Simulation Study in a Realistic Anatomic Geometry Torso Model

We have previously proposed an inverse algorithm for fitting potentials due to an arbitrary bio-electrical source to a single equivalent moving dipole (SEMD) model. The algorithm achieves fast identification of the SEMD parameters by employing a SEMD model embedded in an infinite homogeneous volume conductor. However, this may lead to systematic error in the identification of the SEMD parameters. In this paper, we investigate the accuracy of the algorithm in a realistic anatomic geometry torso model (forward problem). Specifically, we investigate the effect of measurement noise, dipole position and electrode configuration in the accuracy of the algorithm. The boundary element method was used to calculate the forward potential distribution at multiple electrode positions on the body surface due to a point dipole in the heart. We have found that the position and not the number of electrodes as well as the site of the origin of the arrhythmia in the heart have a significant effect on the accuracy of the inverse algorithm, while the measurement noise does not. Finally, we have shown that the inverse algorithm preserves the topology of the source distribution in the heart, thus potentially allowing the cardiac electrophysiologist to efficiently and accurately guide the tip of the catheter to the ablation site.

Lower expression of genes near microRNA in C. elegans germline

Background

MicroRNAs (miRNAs) are recently discovered short non-protein-coding RNA molecules. miRNAs are increasingly implicated in tissue-specific transcriptional control and particularly in development. Because there is mounting evidence for the localized component of transcriptional control, we investigated if there is a distance-dependent effect of miRNA.

Results

We analyzed gene expression levels around the 84 of 113 know miRNAs for which there are nearby gene that were measured in the data in two independent C. elegans expression data sets. The expression levels are lower for genes in the vicinity of 59 of 84 (71%) miRNAs as compared to genes far from such miRNAs. Analysis of the genes with lower expression in proximity to the miRNAs reveals increased frequency matching of the 7 nucleotide "seed"s of these miRNAs.

Conclusion

We found decreased messenger RNA (mRNA) abundance, localized within a 10 kb of chromosomal distance of some miRNAs, in C. elegans germline. The increased frequency of seed matching near miRNA can explain, in part, the localized effects.

Time course analysis of angular control of the body and head while rising from a chair

OBJECTIVE

To use time course information to improve understanding of the vestibular contribution to postural control as one rises from a chair.

MATERIAL AND METHODS

A total of 24 healthy controls and 42 patients with varying degrees of vestibular dysfunction were studied. The time course of the angular motion of the body and head when rising from a chair with eyes open and closed was evaluated. The delay between the onset of the motions of the body and head was compared between subject groups. We also investigated transition points from forward lean of the body to backward reversion and from backward tilt of the head to forward reversion.

RESULTS

With regard to the onset of chair rise, we found a significant difference in the delay between head and body motion between healthy controls and subjects with bilaterally impaired vestibular deficiency only when the eyes were closed. The time between the transition points of the head and body was stable between these groups.

CONCLUSION

The mechanisms controlling the onset of head and body movements differ between normal subjects and those with bilateral vestibular deficits. In the latter, the loss of a reference of gravity causes a decrease in feed-forward postural control, which is compensated for by a somato-sensory feedback mechanism. Visual input seems to provide an alternative reference of gravity.

A short daytime test using correlation dimension for respiratory movement in OSAHS

In order to examine the pathology in patients with obstructive sleep apnoea/hypopnoea syndrome (OSAHS), the nonlinear properties of respiratory movement and breath-to-breath variations during resting wakefulness with eyes closed was investigated. Recording of the respiratory movement using inductive plethysmography was performed on 14 patients with OSAHS and 13 control subjects for 2 h in the supine position during daytime. To calculate the correlation dimension (D2) for respiratory movement, an algorithm proposed by Grassberger and Procaccia was applied. The indices of breath-to-breath variations were estimated. To calculate D2 and breath-to-breath variations, two different segments were selected (200 s each). The value of D2 for respiratory movement in patients with OSAHS was significantly greater than that in control subjects. In the case of > or = 2.0 of D2 for respiratory movement, the sensitivity and specificity of detecting the presence of OSAHS was 85.7% and 76.9%, respectively. On the basis of breath-to-breath variations, only the coefficient of variation of expiratory time for respiratory movement in patients with OSAHS was significantly greater than that in the control subjects. In conclusion, the measurements of correlation dimensions for respiratory movement with a brief period during wakefulness may be a useful index for identifying patients with obstructive sleep apnoea/hypopnoea syndrome.

Inter-species differences of co-expression of neighboring genes in eukaryotic genomes

BACKGROUND

There is increasing evidence that gene order within the eukaryotic genome is not random. In yeast and worm, adjacent or neighboring genes tend to be co-expressed. Clustering of co-expressed genes has been found in humans, worm and fruit flies. However, in mice and rats, an effect of chromosomal distance (CD) on co-expression has not been investigated yet. Also, no cross-species comparison has been made so far. We analyzed the effect of CD as well as normalized distance (ND) using expression data in six eukaryotic species: yeast, fruit fly, worm, rat, mouse and human.

RESULTS

We analyzed 24 sets of expression data from the six species. Highly co-expressed pairs were sorted into bins of equal sized intervals of CD, and a co-expression rate (CoER) in each bin was calculated. In all datasets, a higher CoER was obtained in a short CD range than a long distance range. These results show that across all studied species, there was a consistent effect of CD on co-expression. However, the results using the ND show more diversity. Intra- and inter-species comparisons of CoER reveal that there are significant differences in the co-expression rates of neighboring genes among the species. A pair-wise BLAST analysis finds 8-30 % of the highly co-expressed pairs are duplicated genes.

CONCLUSION

We confirmed that in the six eukaryotic species, there was a consistent tendency that neighboring genes are likely to be co-expressed. Results of pair-wised BLAST indicate a significant effect of non-duplicated pairs on co-expression. A comparison of CD and ND suggests the dominant effect of CD.

Contribution of the vestibular apparatus to postural control when rising from a chair

OBJECTIVE

The everyday act of rising from a chair is known to require the combined angular control of a number of the body's joints, especially those within the pitch plane. Precisely how this control is exerted, however, remains controversial. The aim of this study was to obtain a better understanding of the contribution made by the vestibular apparatus to postural control of the body and head when an individual rises from a chair.

MATERIAL AND METHODS

A total of 24 healthy controls and 38 patients with varying degrees of vestibular dysfunction were examined. Electromagnetic motion sensors were used to analyze the angular control of the head and body as subjects rose from a chair with their eyes open or closed.

RESULTS

We found that unilateral vestibular dysfunction caused fixation of the head with respect to the body, resulting in a loss of spatial stability of the head which was not compensated for by visual input. Visual input did appear to compensate for bilateral vestibular loss, enabling patients with bilateral vestibular apparatus impairment or central disorders to fix the position of their head in space.

CONCLUSION

The act of rising from a chair is normally controlled by vestibular and proprioceptive input; the head is aligned according to the gravitational reference so as to obtain stable visual information. In patients with unilateral vestibular hypofunction, posture is still controlled by these two inputs, although the ability to align the head is diminished. In patients with bilateral vestibular hypofunction or a central disorder, head alignment is maintained using visual input, although it may not be the sole or predominant stabilizing force.