A novel customizable modular bioreactor system for whole-heart cultivation under controlled 3D biomechanical stimulation

In the last decade, cardiovascular tissue engineering has made great progress developing new strategies for regenerative medicine applications. However, while tissue engineered heart valves are already entering the clinical routine, tissue engineered myocardial substitutes are still restrained to experimental approaches. In contrast to the heart valves, tissue engineered myocardium cannot be repopulated in vivo because of its biological complexity, requiring elaborate cultivation conditions ex vivo. Although new promising approaches—like the whole-heart decellularization concept—have entered the myocardial tissue engineering field, bioreactor technology needed for the generation of functional myocardial tissue still lags behind in the sense of user-friendly, flexible and low cost systems. Here, we present a novel customizable modular bioreactor system that can be used for whole-heart cultivation. Out of a commercially obtainable original equipment manufacturer platform we constructed a modular bioreactor system specifically aimed at the cultivation of decellularized whole-hearts through perfusion and controlled 3D biomechanical stimulation with a simple but highly flexible operation platform based on LabVIEW^®. The modular setup not only allows a wide range of variance regarding medium conditioning under controlled 3D myocardial stretching but can also easily be upgraded for e.g. electrophysiological monitoring or stimulation, allowing for a tailor-made low-cost myocardial bioreactor system.     

Infertility: Intra-uterine insemination or timed intercourse after ovarian stimulation for male subfertility? A controlled study

In this randomized trial we investigated whether intra-uterineinsemination (IUI) in couples with male subfertility leads toa higher probability of conception than timed intercourse afterovarian stimulation with human menopausal gonadotrophin (HMG)and human chorionic gonadotrophin (HCG). A total of 76 couplesstarted 249 cycles, of which 47 were cancelled to prevent multiplepregnancies or hyperstimulation. After 202 completed treatmentcycles, 15 pregnancies occurred, 11 after IUI and four aftertimed intercourse. The pregnancy rate per completed cycle withIUI was 10.3% (95% confidence interval: 5.5–17.5%) and4.2% (1.2–10.1%) with timed intercourse. Compared withthe estimated spontaneous chance to conceive, IUI after ovarianstimulation appeared to be more effective in the first threecycles. We conclude that in subfertile couples with a male factor,IUI tends to improve the probability of conception as comparedto timed intercourse when ovarian stimulation is applied, andwe advise such treatment for three cycles.     

Comparison of the particle size distribution curves determined manually and automatically in an accurately calibrated Coulter Counter.

An accurately calibrated Coulter Counter, Model ZB Industrial, was used to compare the size distribution curves of seven different standard particles obtained by calculation and after the attachment of a Channelyser, Model C-1000 coupled to an XY recorder. Comparisons were made at the modes of the curves and it was found that the automatic method consistently reported the particles to be slightly larger.     

The analgesic effects of automatically controlled rotating acupuncture in rats: mediation by endogenous opioid system

The technique of rotating acupuncture needles has long been used to enhance the effects of acupuncture in Oriental medicine. However, it is difficult to standardize and quantify this stimulation condition. Thus we developed an automatically controlled rotating acupuncture (ACRA) system. The present study was conducted to evaluate the analgesic effects of ACRA using 4 different stimulation conditions (i.e., angle and frequency of rotation: 90 degrees + 1 Hz, 90 degrees + 1/4 Hz, 360 degrees + 1 Hz, and 360 degrees + 1/4 Hz) in Sprague-Dawley rats. Tail-flick latency to a noxious radiant heat stimulus in lightly anesthetized rats was measured before and after 15 min of ACRA stimulation at the Zusanli (ST36) acupoint. ACRA stimulations under all of the conditions above produced more potent analgesic effects than plain acupuncture (PA, acupuncture needle insertion only), but only the 90 degrees + 1/4 Hz ACRA condition showed a statistically significant effect versus PA (P < 0.01). Further, the analgesic effect of 90 degrees + 1/4 Hz ACRA was reversed by pretreatment with naloxone (2 mg/kg, i.p.). These results indicate that the 90 degrees + 1/4 Hz ACRA stimulation has the most potent analgesic effect in rats and that this is mediated by the endogenous opioid system.     

Temporal gustatory and salivary responses to capsaicin upon repeated stimulation

Repeated oral stimulation with solutions of 2 ppm capsaicin increased time to maximum intensity, but yielded a decrease in sequential mouth-burn intensity due to a rising minimum irritation rating between stimuli. Two response patterns were observed: for 18 subjects mouth-burn increased, while 14 subjects showed depression upon repeated stimulation. Because of across-subject variability, there was little correlation between parotid salivary response and perceived sensory responses. Capsaicin-stimulated salivary flow was significantly higher than flow stimulated by distilled water in 9 high-flow subjects, but not in 14 low-flow subjects. Oral adaptation to capsaicin may attenuate parotid salivary response, although eaters and noneaters of chili peppers did not differ significantly in their perception of mouth-burn or in salivary flow.     

Repetitive transcranial magnetic stimulation for ALS. A preliminary controlled study

Repetitive transcranial magnetic stimulation (rTMS) of brain can modulate cortical neurotransmission, a novel paradigm of repetitive stimulation termed continuous theta-burst stimulation (cTBS) produces a pronounced and prolonged suppression of motor cortex excitability. The aim of this preliminary study was to investigate whether cTBS of motor cortex could have any beneficial effect in patients with amyotrophic lateral sclerosis (ALS). We performed a double-blind, placebo-controlled trial. Twenty patients with definite ALS were randomly allocated to blinded active or placebo stimulation. Repetitive stimulation of the motor cortex was performed for five consecutive days every month for six consecutive months. The primary outcome was the rate of decline as evaluated with the ALS functional rating scale. The treatment was well tolerated by the patients. Fifteen patients (seven active and eight sham) completed the study and were included in the 6-months analysis. Both active and sham patients deteriorated during treatment, however, active patients showed a modest but significant slowing of the deterioration rate. Though we cannot be sure whether the effects observed can be attributed to cTBS, because of the restricted number of patients studied, further investigation on a larger group of ALS patients is warranted. The results of the pilot study might open up a new therapeutic perspective in ALS based on neuromodulation.     

A device to trigger automatically electrical stimulation at different states of in- or expiration on the background of variable lung inflation in the rabbit

A device is described which permits to obtain a signal at the beginning of in- or expiration respectively. This signal may be used to trigger an electrical stimulator. To permit studies at different states of lung inflation the tracheal cannula is connected to a spirometer circuit. To produce constant positive or negative air pressure this bellows-type spirometer is loaded with exchangeable metal weights. The tracheal pressure is recorded by means of a pressure transducer, the output of which is taken as signal. The device allows accurate compensation of the DC-component of the transducer output resulting from spirometer operation at a maintained positive or negative pressure.     

Parotid salivary flow in response to mechanical and gustatory stimulation in man

To examine further the role of the oral receptors in the masticatory-salivary reflex, a study with eight subjects was performed. The influence on mean parotid salivation of combined alterations in frequency and force of chewing and length of the chewing object was evaluated by group comparison. Salivary flow rate was recorded using a sensitive micromanometer, and the frequency (12, 60 and 90 cycles min-1) and force of chewing (10 and 40% of maximum) were controlled by a metronome and masseter muscle EMG, respectively. The maximum instantaneous flow and the latency of the masticatory-salivary reflex were examined in three subjects. For comparison with mean salivation rate during chewing, gustatory stimulation was performed with 0.5 or 5.0% citric acid. The masticatory-salivary reflex was mainly ipsilateral, and depended upon having an object between the teeth. Salivation increased with increases in frequency and force of chewing and with the number of teeth involved, each parameter of chewing having the greatest influence when increased from a low level of action. The salivation response to chewing showed two phases; the first, presumably due to contraction of the myoepithelial cells, had a latency of 0.2-0.4 s, while the second phase occurred about 1 s later. Our results support the hypothesis that the periodontal mechanoreceptors have a major role in the parotid response to chewing. Application of 0.5 and 5.0% citric acid on the back of the tongue induced dose-dependent parotid secretions, significantly higher than those of chewing. A negative correlation was found between the maximum fluid outputs during chewing and 5.0% citric acid stimulation.     

Implantable stimulation system dedicated for neural selective stimulation

A functional electrical stimulation system is presented, which is dedicated for the selective neural stimulation of the bladder. The proposed system is composed of an internal stimulator (implant) and an external controller. The system is used to produce low-pressure voiding of the bladder in spinal cord injured patients. The implant is powered and operated by the external controller via radio-frequency electromagnetic coupling. All stimulation parameters are chosen externally using the controller and are sent to the implant, which produces the desired stimuli. These stimuli are applied directly to the S₂ nerve which is linked to the sphincter and bladder muscles. A high-frequency signal is used to inhibit the contraction of the sphincter muscle, and low-frequency pulses stimulate the bladder muscle (the detrusor). Dedicated computer software is used by the physician to select the optimal parameters for each patient and to activate the implant through a parallel port interface with built-in transmitter. The parameters are then transferred to a hand-held controller which is used by the technical staff and by the patients themselves. Acute studies have been performed to validate the selective stimulation strategy, and chronic experimentation is currently underway in dogs.     

Neutrophil responses to injury or inflammation impair peripheral gustatory function

The adult peripheral taste system is capable of extensive functional plasticity after injury. Sectioning the chorda tympani (CT), a primary sensory afferent nerve, elicits transient changes in the uninjured, contralateral population of taste receptor cells. Remarkably, the deficits are specific to the sodium transduction pathway. Normal function is quickly restored in the intact nerve, in parallel with an influx of macrophages to both the denervated and uninjured sides of the tongue. However, changing the dietary environment by restricting sodium blocks the macrophage response and prolongs functional alterations. Since the functional deficits occur before macrophages are present in the peripheral taste system, we hypothesized that neutrophils play a role in modulating neural responses in the intact CT. First, the dynamics of the neutrophil response to nerve injury were analyzed in control-fed and sodium-deficient rats. Nerve sectioning briefly increased the number of neutrophils on both the denervated and uninjured sides of the tongue. The low-sodium diet amplified and extended the bilateral neutrophil response to injury, in parallel with the persistent changes in sodium taste function. To test the impact of neutrophils on taste function, we depleted these cells prior to nerve sectioning and recorded neural responses from the intact CT. This treatment restored normal sodium responses in the uninjured nerve. Moreover, recruiting neutrophils to the tongue induced deficits in sodium taste function in both CT nerves. Neutrophils play a critical role in ongoing inflammatory responses in the oral cavity, and may induce changes in taste perception. We also suggest that balanced neutrophil and macrophage responses enable normal neural responses after neural injury.     

一种基于功能磁共振的味觉刺激装置的设计与验证

目的:功能磁共振成像(f MRI)是指在刺激作用下,利用血氧水平依赖信号进行成像,目前常用的感官刺激装置中味觉刺激装置暂无成熟的方案。方法:本文提出了一种基于f MRI的味觉刺激装置的设计与验证。设计了味觉刺激装置的液体输送通路;下位机利用以微控制器为核心的数字电路,完成液体的精确投送;上位机通过Lab VIEW平台编写满足用户实际需求的刺激序列;同时通过数据采集卡将上位机的刺激序列发送至下位机执行,完成实时定量的味觉刺激输送。结果:利用此装置对被试进行了味觉刺激f MRI实验,从采集的功能图像上可以基本验证目前与味觉有关的激活区(脑岛及岛盖区等),可以实现设计的味觉刺激装置功能。结论:本实验设计和验证了一种味觉刺激装置方案,并通过实验验证了它的可用性和实用性。     

Proton change of parotid glands after gustatory stimulation examined by magnetic resonance imaging

The aim of this study was to investigate proton changes of the parotid gland after gustatory stimulation by semi‐quantitative parameters and an empirical mathematical model (EMM) using high‐temporal‐resolution, double‐echo, echo‐planar imaging (EPI). Approved by a local institutional review board, this study examined 20 parotid glands from 10 healthy volunteers (male:female = 6: 4; age ± standard deviation =35.1 ± 14.1 years) with written informed consent obtained. All participants underwent 1.5‐T, double‐echo EPI with gustatory stimulation. Semi‐quantitative parameters, including maximal drop ratio (MDR), time to peak (TTP), drop slope (DS), recovery slope (RS) and recovery ratio (RR), were calculated. The effect of temporal resolution on parotid functional parameters was evaluated. An EMM comprising an output function ( ) and an input function ( ) was also applied to fit all dynamic curves. Kruskal–Wallis test, Wilcoxon test, linear regression analysis and goodness of fit were used for statistical analysis. p < 0.05 was considered to be statistically significant. The signal intensity dropped significantly after gustatory stimulation on the proton density (PD) image (p < 0.01). MDR was 8.26% in the PD image. MDR and RR were negatively associated with time interval, whereas DS and TTP were significantly positively associated with time interval (all p < 0.05). EMM parametric values derived from PD–time curves of parotid glands were 12.04 ± 6.81%, 6.43 ± 4.23 min^–1, 88.73 ± 6.18%, 8.41 ± 4.86 min^–1 and 1.09 ± 1.35 for A_o, k_o, B, A_in and k_in, respectively. Semi‐quantitative functional parameters and EMM parameters using high‐temporal‐resolution, double‐echo EPI allow the quantification of parotid proton changes after gustatory stimulation.     

Cost-effectiveness of aromatase inhibitor co-treatment for controlled ovarian stimulation

BACKGROUND: To compare the clinical results and the cost-effectiveness of using the aromatase inhibitor, letrozole, in conjunction with FSH and FSH alone for controlled ovarian stimulation (COS) in patients undergoing intrauterine insemination (IUI) for a variety of indications. METHODS: Four hundred and thirty-two consecutive patients who underwent 872 IUI cycles were included. The study population was composed of two groups. Group I included 308 patients who underwent 589 IUI cycles with letrozole and FSH for the following indications: anovulation (143 cycles), male factor infertility (147 cycles), unexplained infertility (250 cycles), endometriosis (18 cycles) and combined indications (31 cycles). Group II included 124 patients who underwent 283 IUI cycles who received FSH only for the following indications: ovarian factor infertility (82 cycles), male factor infertility (66 cycles), unexplained infertility (114 cycles), endometriosis (13 cycles) and other indications (8 cycles). Main outcome measures included number of mature follicles >16 mm in diameter, dose of FSH used per cycle, clinical pregnancy rate and cost-effectiveness ratio per pregnancy. RESULTS: FSH dose required for ovarian stimulation was significantly lower when letrozole was used (P < 0.0001). Although a significantly higher number of follicles >16 mm and endometrial thickness at the day of hCG administration (P < 0.0001) were observed in Group II, pregnancy rate per started (14.4 versus 15.9%) and per completed cycles (15.77 versus 18.07%) was the same in Group I and Group II, respectively. IUI cancellation rate was significantly lower with letrozole treatment (P = 0.05%). The cost per cycle was significantly lower in Group I versus Group II (468.93 Can dollars +/- 418.18 versus 1067.28 +/- 921.43; P < 0.0001). The cost-effectiveness ratio was 3249.42 dollars in the letrozole group and 6712.00 dollars in the FSH-only group. CONCLUSION: A letrozole-FSH combination could be an effective ovarian stimulation protocol in IUI cycles. Such a protocol may be more cost-effective than FSH alone because of the difference of FSH dose and cost. A randomized controlled trial is needed to further substantiate this finding.