The Improvement in Function of Poststroke Spasticity by Vibrational and Heated Stone-Needle Therapy and Meridian Dredging Exercise: A Randomized, Controlled, Preliminary Trial

BACKGROUND

Poststroke spasticity (PSS) is a common complication of stroke. Current PSS treatments have been linked to high costs, lack of long-term effectiveness, and undesirable side effects. Vibrational and heated stone-needle therapy (VHS) has not been utilized to treat PSS, and its safety and effectiveness have yet to be proven by high-quality clinical research.

OBJECTIVE

The aim of this study was to determine the effectiveness of VHS combined with meridian dredging exercise (MDE) in patients with PSS.

METHODS

One hundred participants with stroke were included and randomly assigned to a treatment group (VHS plus MDEs) and a control group (MDEs alone). Patients in both groups were treated for 4 weeks. The primary outcome measures were the Modified Ashworth Scale (MAS) and Fugl-Meyer Assessment (FMA), while the secondary outcome measures were the Activity of Daily Living (ADL) Scale and Stroke-Specific Quality of Life Scale (SS-QOL). The evaluations were at baseline (T0) at 4 weeks of treatment (T1) and at 12 weeks of follow-up without treatment (T2).

RESULTS

At T1 and T2, there were significant differences in MAS between the two groups (p = 0.001). From the perspective of distribution, the VHS plus MDE group had significant changes, and the group-time interactions of upper and lower extremities in FMA, ADL, and SS-QOL were statistically significant (p < 0.001), indicating that patients' symptoms improved after treatment. But the overall effect size is small, especially the effect size of improvement in SS-QOL at T1.

CONCLUSION

VHS in combination with MDE can consistently alleviate PSS, enhance limb function, and improve the quality of life of patients with PSS. But we need to optimize the device further and observe the improvement of patients for a more extended period.

Hintergrund

Spastik nach Schlaganfall (PSS; post-stroke spasticity) ist eine häufige Komplikation des Schlaganfalls. Gegenwärtige PSS-Behandlungen sind mit hohen Kosten, mangelnder langfristiger Wirksamkeit und unerwünschten Nebenwirkungen in Verbindung gebracht worden. Vibrierende und erhitzte Steinnadeln (VHS) sind bisher nicht zur Behandlung des PSS eingesetzt worden, und der Nachweis ihrer Sicherheit und Wirksamkeit durch hochwertige klinische Forschung steht noch aus.

Ziel

Beurteilung der Wirksamkeit von vibrierenden und erhitzten Steinnadeln (VHS) in Kombination mit Meridian-Ausbagger-Übungen (MDE) bei Patienten mit PSS.

Methoden

100 Patienten mit Schlaganfall wurden eingeschlossen und per Randomisierung auf eine Behandlungsgruppe (VHS plus MDEs) und eine Kontrollgruppe (nur MDE) aufgeteilt. In beiden Gruppen wurden die Patienten 4 Wochen lang behandelt. Die primären Messinstrumente waren die Modified Ashworth Scale (MAS) und das Fugl-Meyer Assessment (FMA), als sekundäre Messinstrumente wurden die Activity of Daily Living Scale (ADL) und die Stroke-Specific Quality of Life Scale (SS-QOL) erhoben. Die Beurteilungszeitpunkte waren bei Baseline (T0) nach 4 Wochen Behandlung (T1) und nach 12 Wochen Nachbeobachtung ohne Behandlung (T2).

Ergebnisse

Bei T1 und T2 bestanden signifikante Unterschiede bei der MAS zwischen den Gruppen (p = 0.001). Aus der Perspektive der Distribution zeigte die “VHS plus MDE”-Gruppe signifikante Veränderungen, und die Gruppe*Zeit-Interaktionen der oberen and unteren Extremitäten bei FMA, ADL und SS-QOL waren statistisch signifikant (p < 0.001), was darauf hindeutet, dass die Beschwerden der Patienten sich nach der Behandlung besserten. Die Effektstärke ist allerdings gering, insbesondere die der SS-QOL-Verbesserung bei T1.

Schlussfolgerung

Die Anwendung von vibrierenden und erhitzten Steinnadeln in Kombination mit Meridian-Ausbagger-Übungen kann PSS durchgängig lindern, die Funktion der Extremitäten verbessern und die Lebensqualität der Patienten mit PSS erhöhen. Jedoch muss das Produkt weiter optimiert werden, und die Verbesserungen bei den Patienten müssen über einen längeren Zeitraum beobachtet werden.

Mechanism and potential treatments for gastrointestinal dysfunction in patients with COVID-19

The global coronavirus disease 2019 (COVID-19) has become one of the biggest threats to the world since 2019. The respiratory and gastrointestinal tracts are the main targets for severe acute respiratory syndrome coronavirus 2 infection for they highly express angiotensin-converting enzyme-2 and transmembrane protease serine 2. In patients suffering from COVID-19, gastrointestinal symptoms have ranged from 12% to 61%. Anorexia, nausea and/or vomiting, diarrhea, and abdominal pain are considered to be the main gastrointestinal symptoms of COVID-19. It has been reported that the direct damage of intestinal mucosal epithelial cells, malnutrition, and intestinal flora disorders are involved in COVID-19. However, the underlying mechanisms remain unclear. Thus, in this study, we reviewed and discussed the correlated mechanisms that cause gastrointestinal symptoms in order to help to develop the treatment strategy and build an appropriate guideline for medical workers.

In Situ Real-Time Quantitative Determination in Electrochemical Nuclear Magnetic Resonance Spectroscopy

For the purpose of acquiring highly sensitive and differential spectra in in situ electrochemical nuclear magnetic resonance (EC-NMR) spectroscopy, uniform distributions of amplitudes and phases of radio frequency (RF) fields in the sample are needed for consistent flip angles of all nuclei under scrutiny. However, intrinsic electromagnetic incompatibility exists between such requirements with electric properties of the conductive material in an electrolytic cell, including metallic electrodes and ionic electrolytes. This proposed work presents the adverse repercussions of gradually varying electrolyte conductivity, which is strongly associated with the change of ion concentrations in a real-time electrochemical reaction, on spatial distributions of RF field amplitude and phase in the detective zone of an NMR probe coil. To compensate for such a non-linear trend of the spatial dependent distribution, we eliminate different excitation effects of the RF field on the build-in external standard and the electrolyte both situated in nearly the same detection area, as well as promote the greater accuracy of quantitative determination of reactant concentrations. The reliability and effectiveness of the improved in situ EC-qNMR (quantitative NMR) method are confirmed by the real-time monitoring of the electrochemical advanced oxidation process for phenol, in which instant concentrations of reactants and products are detected simultaneously to verify the degradation reaction scheme of phenol.

[A multicenter survey of the accessibility of essential medicines for children in China]

Objective: To investigate the availability, prices and affordability of essential medicines in pediatric population across China, in the hope of improving rational use of medicines. Methods: A multicenter cross-sectional survey of medicine prices, availability and affordability was conducted in 17 provinces, municipalities and autonomous region across east, south-central part, west and north of China. Data on 42 medicines used in pediatric population, both original and generic, were collected in 55 public hospitals from May 26 to June 2, 2017. Availability was expressed as the percentage of hospitals with stock of the target medicine on the day of data collection,and median price ratio (MPR) was the ratio of price upon investigation to international reference. Based on national minimum daily wage, affordability represents the number of working days needed to earn the expense which covers a standard course using the target medicine. Statistical software SPSS 13.0 was applied for descriptive analysis of availability, MPR and affordability. Results: Mean Availability of original and generic medicine was 33% and 32%, with median MPR being 5.43 and 1.55. Among the 19 medicines with price information for both original and generic product, the median MPR was 7.73 and 2.04 respectively. Regarding the five medicines used to treat four common pediatric diseases (pneumonia,peptic ulcer, congenital hypothyroidism, refractory nephrotic syndrome), the affordability was 0.63 (0.16-6.17) d for generic medicine, and 1.03 (0.16-11.53) d for its original counterpart. Conclusions: The availability to both original and generic products of the 42 medicines used in pediatric population was low in China. The prices of generic medicines seem to be lower and affordability higher than those of original medicines. There is an urgent need to improve the availability and affordability of pediatric medicines.

Pancreatic Fat is not significantly correlated with β-cell Dysfunction in Patients with new-onset Type 2 Diabetes Mellitus using quantitative Computed Tomography

Objective: Type 2 diabetes mellitus (T2DM) is a chronic condition resulting from insulin resistance and insufficient β-cell secretion, leading to improper glycaemic regulation. Previous studies have found that excessive fat deposits in organs such as the liver and muscle can cause insulin resistance through lipotoxicity that affects β-cell function. The relationships between fat deposits in pancreatic tissue, the function of β-cells, the method of visceral fat evaluation and T2DM have been sought by researchers. This study aims to elucidate the role of pancreatic fat deposits in the development of T2DM using quantitative computed tomography (QCT), especially their effects on islet β-cell function. Methods: We examined 106 subjects at the onset of T2DM who had undergone abdominal QCT. Estimated pancreatic fat and liver fat were quantified using QCT and calculated. We analysed the correlations with Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) scores and other oral glucose tolerance test-derived parameters that reflect islet function. Furthermore, correlations of estimated pancreatic fat and liver fat with the area under the curve for insulin (AUC_INS) and HOMA-IR were assessed with partial correlation analysis and demonstrated by scatter plots. Results: Associations were found between estimated liver fat and HOMA-IR, AUC_INS, the modified β-cell function index (MBCI) and Homeostatic Model Assessment β (HOMA-β). However, no significant differences existed between estimated pancreas fat and those parameters. Similarly, after adjustment for sex, age and body mass index, only estimated liver fat was correlated with HOMA-IR and AUC_INS. Conclusions: This study suggests no significant correlation between pancreatic fat deposition and β-cell dysfunction in the early stages of T2DM using QCT as a screening tool. The deposits of fat in the pancreas and the resulting lipotoxicity may play an important role in the late stage of islet cell function dysfunction as the course of T2DM progresses.

[Mechanism of inhibitory effect of catalpol on TNF-α induced HAECs cell damage]

Catalpol is an iridoid glycoside extracted from the root of Rehmannia glutinosa. It has been reported to have antioxidant stress effects. Adenosine 5' monophosphate-activated protein kinase( AMPK) plays an important role in inhibiting oxidative stress. This study was designed to investigate the protective effects of catalpol on TNF-α-exposed human aorta epithelial cells( HAECs) via inhibit oxidative stress,and the relationship between catalpol and AMPK was detected by RNA interference technique. Levels of superoxide dismutase( SOD),malonaldehyde( MDA),glutathione( GSH) and lactate dehydrogenase( LDH) were measured with a colorimetric assay kit. The level of ROS was measured with FACS calibur. Western blot was employed to detect the protein expression of AMPK,phosphorylated-AMPK and NOX4. Finally,RNA interference technique was used to investigate the role of AMPK in catalpol-induced protective effects. TNF-α treatment decreased the expression of phosphorylated-AMPK protein level,however,catalpol could reverse the decreased phosphorylated-AMPK level. Catalpol could inhibit NOX4 protein expression and decrease ROS overproduction. After using AMPK siRNA that effects of catalpol on ROS overproduction and NOX4 protein expression inhibition were attenuated. The above results suggest that catalpol inhibits oxidative stress in TNF-α-exposed HAECs by activating AMPK.

Cytological mechanism of astragaloside IV in promoting repair of bone defects

To explore the possible cytological mechanism underlying the role of Astragaloside IV in promoting the repair of bone defects, osteoblasts were cultured in vitro and identified using inverted phase contrast microscopy, alkaline phosphatase (ALP) staining and alizarin red staining.

[Prognostic influence of preoperative Nutritional Risk Screening -2002 (NRS-2002) score for patients with thoracic esophageal squamous cell carcinoma receiving surgery]

Objective: To apply Nutritional Risk Screening-2002(NRS-2002) to perform nutritional status score for the patients with thoracic esophageal squamous cell carcinoma (ESCC) receiving surgery, and to explore the prognostic impact of long-term survival. Methods: A total of 117 patients who were diagnosed with ESCC from 2010 to 2012 were retrospectively analyzed. They recieved standard curative esophagectomy in the Yangzhou University Affiliated Taixing People's Hospital. The nutritional status and risk score for recruited patients were assessed according to the standard of NRS-2002 tool prior to surgery, and these patients were grouped for further analysis according to the median values of NRS-2002 score. Finally, the relationship between NRS-2002 score and prognosis was analyzed. Results: Patients were classified into two groups, with 45 in the NRS-2002<2.0 group, and 72 cases in the NRS-2002≥2.0, respectively. In the NRS-2002<2.0 group, the 1-, 3-, and 5-year progression-free survival (PFS) rates were 75.6%, 44.4% and 40.0% separately, while in the NRS-2002≥2.0 group, the PFS rates were 61.1%, 6.9% and 4.2% respectively, and the differences were statistically significant (P<0.001). Correspondingly, in the NRS-2002< 2.0 group, the 1-, 3-, and 5-year overall survival (OS) rates were 97.8%, 66.7% and 57.8% separately, while in the NRS-2002≥2.0 group, the OS rates were 91.7%, 33.3% and 16.7% respectively, and the differences were also statistically significant (P<0.001). Univariate analysis showed that N stage, TNM stage and NRS-2002 score were closely related to PFS and OS (P<0.05), and T stage was only associated with OS in patients with thoracic esophageal squamous cell carcinoma (P<0.05). Furthermore, multivariate Cox regression analysis showed that N stage (RR=1.640, 95% CI 1.049-2.565, P=0.030) and NRS-2002 (RR=3.154, 95% CI 1.946-5.113, P<0.001) were independent prognostic factors for PFS in patients with ESCC after surgery. Additionally, pathological differentiation (RR=1.556, 95% CI 1.004-2.440, P=0.041), N stage (RR=1.624, 95% CI 1.017-2.593, P=0.042) and NRS-2002 (RR=3.906, 95% CI2.245-6.795, P<0.001) were independent prognostic factors for OS in ESCC patients following surgery. Conclusion: Preoperative nutritional risk screening NRS-2002 score is an independent prognostic factor in patients with ESCC receiving surgery and could be used as a tool for primary screening for nutritional risk.

[Evaluation of the effects of two different modes of orthognathic surgery on upper airway morphology in patients with skeletal Class Ⅲ malocclusion]

PURPOSE

To establish three-dimensional models of upper airway pre- and post-orthognathic surgery in patients with skeletal Class Ⅲ malocclusion, and to compare the effects of different modes of orthognathic surgery on the cross-sectional areas and volumes of upper airway.

METHODS

Twenty-eight patients with skeletal Class Ⅲ malocclusion were divided into 2 groups. Group A (12 patients) underwent bilateral sagittal split ramus osteotomy(BSSRO) for mandibular setback, named single jaw surgery group; group B (16 patients) underwent BSSRO + Le Fort I osteotomy for mandibular setback and maxillary advancement, named bimaxillary surgery group. All patients received CT scanning before (T1) and 3 months after surgery (T2). The three-dimensional models of the upper airway containing velopharynx, glossopharynx and laryngopharynx were established by using Dolphin Imaging 11.7 software. The changes of sagittal diameters, coronal diameters, cross-sectional areas and volumes of the upper airway were measured and compared between the two groups pre- and post- surgery (T1, T2) using SPSS 16.0 software package, respectively.

RESULTS

In velopharynx, the values of group A were decreased after surgery, while the other values of group B were increased except the value of coronal diameter. There was a significant difference between the two groups (P<0.05). In glossopharynx and laryngopharynx, the values of group A and group B were both decreased after surgery. The reduction of the cross-sectional areas and volumes in group A were more obvious than group B (P<0.05).

CONCLUSIONS

The amount of narrowing of the upper airway is smaller in patients undergoing bimaxillary surgery than in patients undergoing mandibular setback surgery.

[Facial symmetry after conservative treatment of unilateral condylar fracture in children: a three-dimensional study]

Objective: To investigate the influence of condylar fractures on the growth of condylars after conservative treatments by three-dimensional measurement. Methods: Twenty three children with unilateral condylar fracture followed-up for at least 1 year in Shanghai Ninth People's Hospital were included from June 2016 to March 2017. CT scans were performed for each patient. Three-dimensional virtual skulls were reconstructed and measuring points were defined with Simplant 11.04 software. The depth of glenoid fossa, height of articular eminence, width, height and depth of condylar, deviation of pogonion were measured. Statistical analyses were conducted to assess difference between the bifid group and the normal group. Results: No difference was observed in the vertical position of crest of the articular eminence between two groups (P=0.110). The vertical position of roof of the glenoid fossa in bifid side was significantly superior than the one in normal side (P=0.010). Bifid side had a shorter (P=0.002) and wider(P=0.002) condylar than normal side did. No difference was observed in the depth of condylar between two groups (P=0.071). The average deviation of pogonion was (0.69±1.75) mm (P=0.072) from sagittal plan. Conclusions: This short-termed study indicates that children's growth potential of condylar is under average after conservative treatments. Because the bone hyperosteogeny of glenoid fossa compensates the hypotrophy of condylar, no deviation of pogonion is detected.

Variability in carbon uptake and (re)cycling in Antarctic cryptoendolithic microbial ecosystems demonstrated through radiocarbon analysis of organic biomarkers

Cryptoendolithic lichens and cyanobacteria living in porous sandstone in the high-elevation McMurdo Dry Valleys are purported to be among the slowest growing organisms on Earth with cycles of death and regrowth on the order of 10³ -10⁴  years. Here, organic biomarker and radiocarbon analysis were used to better constrain ages and carbon sources of cryptoendoliths in University Valley (UV; 1,800 m.a.s.l) and neighboring Farnell Valley (FV; 1,700 m.a.s.l). Δ¹⁴ C was measured for membrane component phospholipid fatty acids (PLFA) and glycolipid fatty acids, as well as for total organic carbon (TOC). PLFA concentrations indicated viable cells comprised a minor (<0.5%) component of TOC. TOC Δ¹⁴ C values ranged from -272‰ to -185‰ equivalent to calibrated ages of 1,100-2,550 years old. These ages may be the result of fractional preservation of biogenic carbon and/or sudden large-scale community death and extended period(s) of inactivity prior to slow recolonization and incorporation of ¹⁴ C-depleted fossil material. PLFA Δ¹⁴ C values were generally more modern than the corresponding TOC and varied widely between sites; the FV PLFA Δ¹⁴ C value (+40‰) was consistent with modern atmospheric CO₂ , while UV values ranged from -199‰ to -79‰ (calibrated ages of 1,665-610 years). The observed variability in PLFA Δ¹⁴ C depletions is hypothesized to reflect variations in the extent of fixation of modern atmospheric CO₂ and the preservation and recycling of older organic carbon by the community in various stages of sandstone recolonization. PLFA profiles and microbial community compositions as determined by molecular genetic characterizations and microscopy differed between the two valleys (e.g., predominance of biomarker 18:2 [>50%] in FV compared to UV), representing microbial communities that may reflect distinct stages of sandstone recolonization and/or environmental conditions. It is thus proposed that Dry Valley cryptoendolithic microbial communities are faster growing than previously estimated.

Afatinib Decreases P-Glycoprotein Expression to Promote Adriamycin Toxicity of A549T Cells

We investigated the reversal effect of afatinib (AFT) on activity of adriamycin (ADR) in A549T cells and clarified the related molecular mechanisms. A549T cells overexpressing P-glycoprotein (P-gp) were resistant to anticancer drug ADR. AFT significantly increased the antitumor activity of ADR in A549T cells. AFT increased the intracellular concentration of ADR by inhibiting the function and expression of P-gp at mRNA and protein levels in A549T cells. Additionally, the reversal effect of AFT on P-gp mediated multidrug resistance (MDR) might be related to the inhibition of PI3K/Akt pathway. Cotreatment with AFT and ADR could enhance ADR-induced apoptosis and autophagy in A549T cells. Meanwhile, the co-treatment significantly induced cell apoptosis and autophagy accompanied by increased expression of cleaved caspase-3, PARP, LC3B-II, and beclin 1. Apoptosis inhibitors had no significant effect on cell activity, while autophagy inhibitors decreased cell viability, suggesting that autophagy may be a self protective mechanism of cell survival in the absence of chemotherapy drugs. Interestingly, when combined with AFT and ADR, inhibition of apoptosis and/or autophagy could enhance cell viability. These results indicated that in addition to inhibit P-gp, ADR-induced apoptosis, and autophagy promoted by AFT contributed to the antiproliferation effect of combined AFT and ADR on A549T cells. These findings provide evidence that AFT combined ADR may achieve a better therapeutic effect to lung cancer in clinic. J. Cell. Biochem. 119: 414-423, 2018. © 2017 Wiley Periodicals, Inc.

[Characterization of Phosphorus Forms in Organic Composts and Their Effects on Leaf Phosphorus Content of Castanea mollissima in Chinese Chestnut Producing Area]

Characterization of the forms of phosphorus (P) in four organic composts including compost of hulls and leaves of Castanea mollissima, edible fungi residues, corn stalks and chicken manure (BYZ), compost of edible fungi residues and chicken manure(ZF), composts of hulls and leaves of C. mollissima, edible fungi residues and chicken manure (BZ1 and BZ2) in Chinese chestnut producing area was conducted by sequential P fractionation developed by Dou et al. Field trial was conducted to study the effects of compost application on leaf phosphorus content of Castanea mollissima. The results showed that total phosphorus content(TP) of organic composts ranked as follows:BZ1(10.61 g·kg^-1) > ZF(9.03 g·kg^-1) > BYZ(8.56 g·kg^-1) > BZ2(7.68 g·kg^-1), and the inorganic phosphorus(P_i) accounted for 62.88%-73.62% of the total phosphorus in the organic composts. The content and proportion of HCl-P in the total fractionated phosphorus(P_rt) was the highest among P forms in ZF, while that of H₂O-P was the highest in BYZ, BZ1 and BZ2. The content of NaOH-P was very low in all the composts. Active H₂O-Por NaHCO₃-P had the highest inorganic phosphorus proportion(89.17%-96.00%) of all the P forms. The major P_iforms in BZ2 were H₂O- and HCl-extractable P fractions, while H₂O-P_i, HCl-P_i and NaHCO₃-P_i were major P_i forms in BYZ, BZ1 and ZF. Residual-P was the predominant organic phosphorus form, and BZ2 showed the highest Residual-P proportion of the total fractionated phosphorus(P_rt) among all the composts. Leaf phosphorus contents per unit area of Castanea mollissima by field trial on the added phosphorus-equivalent basis were expressed as:BZ2>BZ1>BYZ>ZF>CK. Increment of leaf phosphorus content per unit area in Julyand per month on average showed positive relationship with the content and proportion of H₂O-P_i in the total fractionated phosphorus of composts, which presumably played a key role in leaf phosphorus absorption of C. mollissima measured in the year of deep concentrated fertilization. The results suggested that composts of hulls and leaves of C. mollissima, edible fungi residues and chicken manure (BZ2) was a good choice in given area for aerobic composting raw material system in which organic wastes from Chinese chestnut industry accounted for 80% (hulls and leaves of Castanea mollissima and edible fungi residues accounted for 60% and 20% respectively), which had a high proportion of H₂O-P_i and organic Residual-P pool and led to the highest leaf phosphorus content of C. mollissima.

[Medial anterior flange overhang related to the prosthesis selection determined by femoral sizer in total knee arthroplasty]

Objective: To evaluate the medial anterior flange overhang related to the femoral prosthesis size determined by femoral sizer in total knee arthroplasty. Methods: Sixty one cases of varus knee osteoarthritis (61 knees) were analyzed from January 2014 to January 2015, 14 males and 47 females, aged (66.8±6.8) year old. 3D models of distal femur were established by Mimics, total knee arthroplasty surgeries were simulated and the medial and lateral femoral condylar anteroposterior diameter were measured. According to the AP diameter of lateral femoral condyle (lateral condyle group) and femoral sizer (sizer group), different size of the PFC Sigma femoral prosthesis models were imported to mimics, and the coverage of medial anterior femoral flange were compared. Results: The AP diameter of lateral femoral condyle[(55.76±3.64) mm]was significantly less than the sizer group[(57.02±3.59) mm], P<0.05. The distal femur aspect ratio for male (1.2 %±0.1%) and female (1.2%±0.1%) has no statistically difference (P>0.05). Femoral prosthesis sizes, the uncoverage diameter of the anterior chamfer line, midpoint of the flange in the sizer group were significantly larger than the lateral condyle group (P<0.05). The femoral size, overhang ratio of anterior chamfer line and midpoint of the flange in male were significantly larger than females (P<0.05). Conclusion: The AP diameter determined by femoral sizer instrument had a tendency to larger prosthesis, and the risks of medial femoral anterior flange overhang increased. Medial anterior flange overhang in male was significantly less than female, but the difference had no correlation to the distal femur asepect ratio.

Alisol B 23-acetate protects against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes involved in bile acid homeostasis

Intrahepatic cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Appropriate regulation of bile acids in hepatocytes is critically important for protection against liver injury. In the present study, we characterized the protective effect of alisol B 23-acetate (AB23A), a natural triterpenoid, on alpha-naphthylisothiocyanate (ANIT)-induced liver injury and intrahepatic cholestasis in mice and further elucidated the mechanisms in vivo and in vitro. AB23A treatment dose-dependently protected against liver injury induced by ANIT through reducing hepatic uptake and increasing efflux of bile acid via down-regulation of hepatic uptake transporters (Ntcp) and up-regulation of efflux transporter (Bsep, Mrp2 and Mdr2) expression. Furthermore, AB23A reduced bile acid synthesis through repressing Cyp7a1 and Cyp8b1, increased bile acid conjugation through inducing Bal, Baat and bile acid metabolism through an induction in gene expression of Sult2a1. We further demonstrate the involvement of farnesoid X receptor (FXR) in the hepatoprotective effect of AB23A. The changes in transporters and enzymes, as well as ameliorative liver histology in AB23A-treated mice were abrogated by FXR antagonist guggulsterone in vivo. In vitro evidences also directly demonstrated the effect of AB23A on FXR activation in a dose-dependent manner using luciferase reporter assay in HepG2 cells. In conclusion, AB23A produces protective effect against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes.

Pharmacokinetics of phosphocreatine and its active metabolite creatine in the mouse plasma and myocardium

BACKGROUND

The pharmacokinetic (PK) studies of phosphocreatine (PCr) and its active metabolite creatine (Cr) are considerably lacking. This study is to comparatively investigate the PK profiles of PCr and Cr in mice plasma and myocardium as well as the ATP level.

METHODS

After iv administration of equimolar PCr and preformed Cr to healthy and Pit-induced myocardial ischemic mice, plasma and myocardium samples were analyzed for exogenous PCr, Cr and related ATP concentrations using a specific ion-pair reversed-phase HPLC-UV assay.

RESULTS

The plasma C-T data of iv PCr and Cr were well fitted to two-compartment model. Following iv PCr, Cr appeared in plasma as early as 1.0 min postdose with a longer t1/2 than PCr and had a fm of 72%. The mice dosed iv PCr preceded 5 min by ip Pit 30 U/kg showed longer t1/2β PCr and t1/2 Cr in plasma and elevated Cmax, Cr and Cmax, ATP in myocardium compared with mice dosed iv PCr alone, and it was estimated that about 40% ATP produced by iv PCr was from Cr.

CONCLUSION

The PCr in plasma is converted to Cr rapidly and mostly, and shows an elimination rate limited (ERL) metabolite disposition. Iv PCr caused a significantly elevated and long-lasing myocardial ATP and Cr levels. The Pit-induced myocardial ischemia brings slower elimination of PCr and Cr and higher peak concentrations of Cr and ATP in myocardium. The metabolite Cr at least partially mediates PCr-caused rise in myocardial ATP level and also possibly the cardio-protective effects of PCr.

Transcriptome sequencing of sea cucumber (Apostichopus japonicus) and the identification of gene-associated markers

Sea cucumber (Apostichopus japonicus) is an ecologically and economically important species in East and South-East Asia. This project aimed to identify large numbers of gene-associated markers and differentially expressed genes (DEGs) after lipopolysaccharides (LPS) challenge in A. japonicus using high-throughput transcriptome sequencing. A total of 162 million high-quality reads of 174 million raw reads were obtained by deep sequencing using Illumina HiSeq™ 2000 platform. Assembly of these reads generated 94 704 unigenes, with read length ranging from 200 to 16 153 bp (average length of 810 bp). A total of 36 005 were identified as coding sequences (CDSs), 32 479 of which were successfully annotated. Based on the assembly transcriptome, we identified 142 511 high-quality single nucleotide polymorphisms (SNPs). Among them, 33 775, 63 120 and 45 616 were located in sequences without predicted CDS (non-CDSs), CDSs and untranslated regions (UTRs), respectively. These putative SNPs included 82 664 transitions and 59 847 transversions. Totally, 89 375 (59.1%) were distributed in 15 473 known genes. A total of 6417 microsatellites were detected in 5970 unigenes, 3216 of which were annotated and 2481 were successfully subjected for primer design. The numbers of simple sequence repeats (SSRs) identified in non-CDSs, CDSs and UTRs were 2367, 2316 and 1734. These potential SNPs and SSRs are expected to provide abundant resources for genetic, evolutionary and ecological studies in sea cucumber. Transcriptome comparison revealed 1330, 1347 and 1291 DEGs in the coelomocytes of A. japonicus at 4 h, 24 h and 72 h after LPS challenge, respectively. Approximately 58.4% (1802) of total DEGs have been successfully annotated.

Effects of freezing rates and cryoprotectant on thermal expansion of articular cartilage during freezing process

The intact articular cartilage has not yet been successfully preserved at low temperature most likely due to the volume expansion from water to ice during freezing. The objective of this current study focuses on examining thermal expansion behavior of articular cartilage (AC) during freezing from 0 degree C to -100 degree C. Thermo Mechanical Analysis (TMA) was used to investigate the effects of different concentrations of dimethyl sulphoxide (DMSO) (0%, 10%, 30% and 60% v/v) and different freezing rates (1 C/min, 3 C/min and 5 C/min). The results showed that: (1) the inhomogeneous thermal expansion (or contraction) presents due to inhomogeneous water distributions in articular cartilage during freezing, which also may be the most likely reason that the matrix has been damaged in cryopreserved intact articular cartilage; (2) at the phase transition temperature range, the maximum thermal strain change value for 5C/min is approximately 1.45 times than that for 1 C/min, but the maximum thermal expansion coefficient of the later is about six times than that of the former; (3) the thermal expansion coefficient decreases with increasing cooling rate at the unfrozen temperature region, but some opposite results are obtained at the frozen temperature region; (4) the higher the DMSO concentration is, at the phase change temperature region, the smaller the thermal strain change as well as the maximum thermal expansion coefficient are, but DMSO concentration exhibits little effect on the thermal expansion coefficient at both unfrozen and frozen region. Once the DMSO concentration increasing enough, e.g. 60% v/v, the thermal strain decreases linearly and smoothly without any abrupt change due to little or no ice crystal forms (i.e. vitrification) in frozen articular cartilage. This study may improve our understanding of the thermal expansion (or contraction) behavior of cryopreserved articular cartilage and it may be useful for the future study on cryopreservation of intact articular cartilage.

[Research progresses of pharmacokinetics of traditional Chinese medicine]

With the deepening of modernization of traditional Chinese medicine (TCM) and continuing emergence of new theories, methods and techniques, a very rapid and significant development has been achieved in the pharmacokinetics (PK) of TCM. This paper reviews the main research progresses of PK of TCM, including integrated PK of multiple effective components of TCM, fingerprint PK of TCM, novel dosage form PK of TCM, polysaccharide PK of TCM and drug interactions of TCM; and further sets up the prospects.

Ursolic acid suppresses IL-6 induced C-reactive protein expression in HepG2 and protects HUVECs from injury induced by CRP

OBJECTIVE

To investigate the inhibitory effects of ursolic acid (UA) on the expression of C-reactive protein (CRP) induced by IL-6 in HepG2 cells and the protective effects on the CRP-induced injury to human umbilical vein endothelial cells (HUVECs).

METHODS

HepG2 cells were treated with IL-6 or IL-6 and different concentrations of UA for 48 h, then the cells were collected. The total protein and RNA of the cells were extracted for western blotting and RT-PCR methods to detect CRP protein and mRNA expression. HUVECs were treated with CRP or CRP and different concentrations of UA for 24h. Cell proliferation in each group was assayed by MTT. Cells were collected for western blotting and RT-PCR methods to detect VCAM-1, LOX-1 protein or mRNA expression.

RESULT

IL-6 can significantly increase CRP protein and mRNA expression in HepG2 cells, and this effect of IL-6 can be decreased by UA (6.25, 12.5, 25 μmol/L) markedly in a dose-dependent manner. UA can inhibit CRP-induced proliferation of HUVECs. CRP can obviously increase LOX-1/VCAM-1 expression in HUVECs, both on mRNA and protein levels and the effect of CRP can be inhibited by UA (5, 10, 20 μmol/L) in a dose-dependent manner.

CONCLUSION

UA can reduce the over expression of CRP in HepG2 cells induced by IL-6 and inhibit the increased expression of VCAM-1 and LOX-1 in HUVECs caused by CRP. Our research suggests that UA can reduce CRP levels in plasma and prevent inflammatory cytokines from injuring endothelial cells by inhibiting the hepatic synthesis of CRP. So UA may have positive significance for prevention and treatment of atherosclerosis and other cardiovascular diseases.

Observation of turbulence suppression after electron-cyclotron-resonance-heating switch-off on the HL-2A tokamak

The formation of a transient internal transport barrier (ITB) is observed after the electron-cyclotron-resonance-heating (ECRH) switch-off in the HL-2A plasmas, characterized by transient increase of central electron temperature. The newly developed correlation reflectometer provided direct measurements showing reduction of turbulence in the region of steepened gradients for the period of ITB formation triggered by the ECRH switch-off. Furthermore, the reduction of core turbulence is correlated in time with the appearance of a low-frequency mode with a spectrally broad poloidal structure that peaks near zero frequency in the core region. These structures have low poloidal mode number, high poloidal correlation, and short radial correlation and are strongly coupled with high-frequency ambient turbulence. Observation indicates that these structures play important roles in the reduction of the core turbulence and in improvements of the core transport after the off-axis ECRH is turned off.

A randomised controlled study of risperidone and olanzapine for schizophrenic patients with neuroleptic-induced acute dystonia or parkinsonism

The objective of this study was to compare the effects of risperidone and olanzapine in schizophrenic patients with intolerant extrapyramidal side effects (EPS) on first generation antipsychotics. We conducted an 8-week, rater-blinded, flexible dose study. Seventy patients with schizophrenia, who met the DSM-IV research criteria of having neuroleptic-induced acute dystonia or parkinsonism, were randomly assigned to risperidone or olanzapine group. The primary outcome was a comparison of the incidence of concomitant anticholinergic drugs usage between the groups to manage their acute dystonia and parkinsonism. The average doses of risperidone and olanzapine from baseline to study end point were 1.8-3.5 mg/day and 7.7-11.7 mg/day, respectively. There were no significant differences in demographic data, severity of EPS or psychotic symptoms between the groups at baseline assessment. Patients taking risperidone had significantly higher incidence of using anticholinergic drugs to manage acute dystonia or parkinsonism overall during the study (OR = 5.17, 95%CI = 1.49-17.88, P = 0.013). There was no significant between-group difference in the changing of rating scales of EPS and psychotic symptoms. The results of our study favour olanzapine as a better choice in schizophrenic patients with intolerant EPS. Double-blinded, fixed dose and different ethnical study for EPS-intolerant schizophrenic patients is needed to confirm the results of our study.

β-induced Alfvén eigenmodes destabilized by energetic electrons in a Tokamak plasma

The β-induced Alfvén eigenmode (BAE) excited by energetic electrons has been identified for the first time both in the Ohmic and electron cyclotron resonance heating plasma in HL-2A. The features of the instability, including its frequency, mode number, and propagation direction, can be observed by magnetic pickup probes. The mode frequency is comparable to that of the continuum accumulation point of the lowest frequency gap induced by the shear Alfvén continuous spectrum due to finite β effect, and it is proportional to Alfvén velocity at thermal ion β held constant. The experimental results show that the BAE is related not only with the population of the energetic electrons, but also their energy and pitch angles. The results indicate that the barely circulating and deeply trapped electrons play an important role in the mode excitation.

[Long-term outcome of tension-free hernioplasty for inguinal hernia complicated with liver cirrhosis and ascites]

OBJECTIVE

To review tension-free repairing for the patients with inguinal hernia complicated with cirrhosis and ascites.

METHODS

Tension-free herniorrhaphy was performed in 16 cases with inguinal hernia complicated with cirrhosis and ascites from November 1999 to November 2003. The laboratory data before and after the operation were compared and analyzed in this group.

RESULTS

Of the patients, 13 cases were male and 3 were female, the mean age was (64 ± 12) years (range, 37 - 85 years). The liver function was classified as A degree in 4 case, B degree in 10 cases and C degree in 2 patients by using Child score. The operation was successfully carried out in all patients without complications and post-operative hepatoencephalopathy. There was no significant change in the plasma total protein, bilirubin, prothrombin activity and international normalized ratio (INR) after the operation. And the levels of albumin, globulin and white blood cell count changed remarkably after the operation (all P < 0.05). Plasma albumin level was obviously effected by the operation and treatment (P = 0.006). The mean follow-up time was 72.5 months (57 - 102 months). No recurrence occurred during the follow-up. There was no patient died in 30 days after the operation. Seven cases (43.8%) died in the later period of follow-up.

CONCLUSIONS

The tension-free repairing is feasible for the inguinal hernia complicated with cirrhosis and ascites. More attention should be paid to the level of plasma albumin and it should be corrected in time. The liver cirrhosis and its complications will progress after the operation with a poor prognosis.

Observation of a spontaneous particle-transport barrier in the HL-2A tokamak

Using the profile analysis, the density perturbation transport analysis, and the Doppler reflectometry measurement, for the first time a spontaneous and steady-state particle-transport barrier has been evidenced in the Ohmic plasmas in the HL-2A tokamak with no externally applied momentum or particle input except the gas puffing. A threshold in density has been found for the observation of the barrier. The particle diffusivity is well-like, and the convection is found to be inward outside the well and outward inside the well. The formation of the barrier coincides with the transition between the trapped electron mode and the ion temperature gradient driven mode.

Protective effect of tea polyphenols against paracetamol-induced hepatotoxicity in mice is significanly correlated with cytochrome P450 suppression

AIM: To investigate the hepatoprotective activity of tea polyphenols (TP) and its relation with cytochrome P450 (CYP450) expression in mice.

METHODS: Hepatic CYP450 and CYPb₅ levels were measured by UV-spectrophotometry in mice 2 d after intraperitoneal TP (25, 50 and 100 mg/kg per day). Then the mice were intragastricly pre-treated with TP (100, 200 and 400 mg/kg per day) for six days before paracetamol (1000 mg/kg) was given. Their acute mortality was compared with that of control mice. The mice were pre-treated with TP (100, 200, and 400 mg/kg per day) for five days before paracetamol (500 mg/kg) was given. Hepatic CYP2E1 and CYP1A2 protein and mRNA expression levels were evaluated by Western blotting, immunohistochemical staining and transcriptase-polymerase chain reaction.

RESULTS: The hepatic CYP450 and CYPb₅ levels in mice of TP-treated groups (100, 200 and 400 mg/kg per day) were decreased in a dose-dependent manner compared with those in the negative control mice. TP significantly attenuated the paracetamol-induced hepatic injury and dramatically reduced the mortality of paracetamol-treated mice. Furthermore, TP reduced CYP2E1 and CYP1A2 expression at both protein and mRNA levels in a dose-dependent manner.

CONCLUSION: TP possess potential hepatoprotective properties and can suppress CYP450 expression.

Long-range correlations of density fluctuations in the Kerner-Klenov-Wolf cellular automata three-phase traffic flow model

Detrended fluctuation analysis (DFA) is a useful tool to measure the long-range power-law correlations in 1f noise. In this paper, we investigate the power-law dynamics behavior of the density fluctuation time series generated by the famous Kerner-Klenov-Wolf cellular automata model in road traffic. Then the complexities of spatiotemporal, average speed, and the average density have been analyzed in detail. By introducing the DFA method, our main observation is that the free flow and wide moving jam phases correspond to the long-range anticorrelations. On the contrary, at the synchronized flow phase, the long-range correlated property is observed.

Fluorescence microscopy as a tool for in situ life detection

The identification of extant and, in some cases, extinct bacterial life is most convincingly and efficiently performed with modern high-resolution microscopy. Epifluorescence microscopy of microbial autofluorescence or in conjunction with fluorescent dyes is among the most useful of these techniques. We explored fluorescent labeling and imaging of bacteria in rock and soil in the context of in situ life detection for planetary exploration. The goals were two-fold: to target non-Earth-centric biosignatures with the greatest possible sensitivity and to develop labeling procedures amenable to robotic implementation with technologies that are currently space qualified. A wide panel of commercially available dyes that target specific biosignature molecules was screened, and those with desirable properties (i.e., minimal binding to minerals, strong autofluorescence contrast, no need for wash steps) were identified. We also explored the potential of semiconductor quantum dots (QDs) as bacterial and space probes. A specific instrument for space implementation is suggested and discussed.

Decolorization of cotton pulp black liquor by pleurotus ostreatus in a bubble-column reactor

Decolorization of cotton pulp black liquor by Pleurotus ostreatus B1 in a bubble-column reactor (BCR) was studied. The optimal conditions for the running of BCR are 30 degrees C, pH 6.0, aeration rate 1.2 L min(-1), and mycelial age 7 days. Under the optimal conditions, the BCR was run for four cycles (each cycle, 12 days) and the same mycelial pellets were reused. The ultimate decolorization and COD removal rates are 76% and 80%, respectively.

A novel DFNA5 mutation, IVS8+4 A>G, in the splice donor site of intron 8 causes late-onset non-syndromic hearing loss in a Chinese family

We report here the clinical, genetic, and molecular characteristics of a large Chinese family exhibiting non-syndromic, late-onset autosomal dominant sensorineural hearing loss. Clinical evaluation revealed variable phenotypes of hearing loss in terms of severity and age-at-onset of disease in these subjects. Genome-wide linkage analysis mapped the disease gene to the DFNA5 locus with a maximum two-point log odds score of 5.39 at [theta] = 0 for marker D7S2457. DNA sequencing of DFNA5 revealed a novel heterozygous IVS8+4 A>G substitution in the splice donor site of intron 8. Reverse transcriptase-polymerase chain reaction (RT-PCR) showed skipping of exon 8 in the mutant transcript. This mutation faithfully cosegregated with hearing loss in the family. In addition, the mutation was absent in 100 unrelated control DNA samples of Chinese origin. The IVS8+4 A>G mutation is predicted to create a shift in the reading frame and introduce a stop codon at position 372, thereby resulting in a prematurely truncated DFNA5 protein. Up to date, a total of four mutations in DFNA5 have been reported to lead to hearing impairment, all of them result in skipping of exon 8 at the mRNA level. Our findings provide further support for the hypothesis that DFNA5-associated hearing loss is caused by a very specific gain-of-function mutation.

The impact of modifiable risk factors on mortality from prostate cancer in populations of the Asia-Pacific region

Mortality from cancer of the prostate is increasing in the Asia-Pacific, when much of this region is undergoing a transition to a Western lifestyle. The role that lifestyle factors play in prostate cancer appears limited, but existing data mainly are from the West. We conducted an individual participant data analysis of 24 cohort studies involving 320,852 men (83% in Asia). Cox proportional hazard models were used to quantify associations between risk factors and mortality from prostate cancer. There were 308 deaths from prostate cancer (14% in Asia) during 2.1 million person-years of follow-up. The age-adjusted hazard ratio (95% confidence interval; CI) for men with body mass index (BMI) 28 kg/m2 or more, compared with below 25, was 1.55 (1.12 - 2.16); no such significant relationship was found for height or waist circumference. The BMI result was unchanged after adjustment for other variables, was consistent between Asia and Australia/New Zealand (ANZ) and did not differ with age. There was no significant relationship with diabetes, glucose or total cholesterol (p > or = 0.18). Smoking, alone, showed different effects in the two regions, possibly due to the relative immaturity of the smoking epidemic in Asia. In ANZ, the multiple-adjusted hazard ratio for an extra 5 cigarettes per day was 1.12 (95%CI: 1.03 - 1.22), whereas in Asia it was 0.77 (0.56 - 1.05). Body size is an apparently important determinant of prostate cancer in the Asia-Pacific. Evidence of an adverse effect of smoking is conclusive only in the predominantly Caucasian parts of the region.

Mutation spectrum and polymorphisms in ATP7B identified on direct sequencing of all exons in Chinese Han and Hui ethnic patients with Wilson's disease

Wilson's disease (WD), an autosomal recessive copper transport disorder, usually presents with symptoms involving the liver or central nervous system. The disease is caused by a large number of mutations in the ATP7B gene comprising 21 expressed exons. Some of the mutations appear to be population specific, whereas others are found in probands from a variety of different ethnic backgrounds. This paper presents the results of screening of the ATP7B gene by means of the direct sequencing of all exons in the gene in 39 Han and one Hui ethnic Chinese patients. Nineteen novel mutations were revealed along with nine others that have been previously described; 57.5% of the mutations were located in exons 8, 13, and 12. In particular, the Arg778Leu mutation in exon 8 was found in 55% of these Chinese patients in at least one allele. Five patients were homozygotes and 17 patients were heterozygotes for Arg778Leu. The detection rate on direct sequencing of the polymerase chain reaction products of all exons of the ATP7B gene in 40 unrelated patients was 83.8% of alleles. Seventeen polymorphisms were also identified in patients and healthy controls. We first reported the presence of ATP7B mutations in Chinese Hui ethnic patients and summarize our results here along with the previously reported findings. A significant correlation between genotype and phenotype was not found in 37 homozygotes and 52 heterozygotes for Arg778Leu.

Escherichia coli disinfection by electrohydraulic discharges

We study the survival of single-strain Escherichia coli colonies in aqueous media exposed to 5.5 kV, 90 kA electrohydraulic discharges (EHD). The probability of survival (Pn) of a 4 x 10(7) cfu mL(-1) E. coli population after n consecutive EHDs follows a logit distribution: In(Pn/ 100 - Pn) = 1.329 - 1.579 ln n with r2 = 0.993 that corresponds to lethal doses of LD50 = 2.2 and LD90 = 10.5 EHDs. Considering that the reactor is thoroughly mixed during each discharge and that LD50 = 0.9 values are nearly independent of E. coli concentrations in the range of 2 x 10(3) < or = E coli/cfu mL(-1) < or = 3 x 10(6), we ascribe the nonexponential Pn decay of single-strain E. coli colonies to a shielding phenomenon where inactive cells protect the successively smaller numbers of viable cells in the EHD. The qualitatively similar concentration dependence observed for survival under 254 nm of radiation, in contrast with the lower resistance of denser colonies to 20 kHz power ultrasound and the delayed onset of extracellular beta-D-galactosidase activity in bacterial populations already decimated by EHDs, support the view that UV radiation is the dominant disinfection agent generated by electrohydraulic discharges.

Six months follow-up of patients with methamphetamine psychosis

BACKGROUND

It has been nearly 50 years since the psychotic state caused by amphetamine was first reported. However, the prognosis of methamphetamine (MAP) psychosis and its relationship with chronic schizophrenia are still vague. Some authors preferred MAP psychosis model of schizophrenia, while other studies found difference between the two groups of patients in the aspects of negative symptoms.

METHODS

In this study we followed 21 psychiatric inpatients with diagnosis of MAP psychosis. Schedule for affective disorders and schizophrenia (SADS), scale for assessment of negative symptoms (SANS) and global assessment scale (GAS) were used for evaluation of these patients during admission and six months after discharge.

RESULTS

Seventeen patients were interviewed and eight of them confessed reuse of MAP. The follow-up examinations found decreased total scores of delusion and hallucination in SADS and increased GAS scores. The SANS scores of the MAP psychotic patients in this study were lower than moderate level. No significant change could be found for most SANS subcategory scores except some items.

CONCLUSIONS

Most MAP psychotic patients followed in this study improved much in six months. The results of the SANS evaluation and the clinical course for six months indicated that the MAP psychosis is a psychotic disorder different from chronic schizophrenia.

Motion processing in pigeon tectum: equiluminant chromatic mechanisms

Recent psychophysical and neurophysiological studies have suggested that, in mammals, there are interactions between the P (colour processing) and M (motion processing) visual pathways, which were previously believed to be parallel and separate. In this study, the role colour information plays in the coding of object motion was determined in the tectofugal pathway of pigeons. The responses of motion-sensitive neurons in the tectum to moving stimuli formed by chromatic contrast were recorded extracellularly using standard single-unit recording techniques. A moving coloured object was presented on a uniform (opponent coloured) background (e.g. blue-on-yellow, red-on-green and black-on-white). Through systematically manipulation of the luminance contrast between object and background, an equiluminant condition was generated. It was found that, at chromatic equiluminance, the majority of cells maintain some level of response. The mean magnitude of the response at equiluminance was about one-third of the response at maximal contrast to the same chromatic border. These results suggest that tectal units can detect motion of a pattern defined by a pure colour contour, although the strength of output is considerably weaker than that for the movement of patterns formed by luminance contrast.

A mammalian model of optic-flow utilization in the control of locomotion

Gibson (1966, 1979) and Lee (1976) have described the potential usefulness of optic-flow information for the control of locomotion. One variable that might be particularly important for an animal approaching a target is time-to-collision, which Lee argues is most efficiently specified by the tau margin (the inverse of the relative rate of expansion of the target image on the retina). In humans, most empirical studies of optic flow have required perceptual judgements or have examined catching/intercepting behaviours. In animals, most studies have been strictly observational. This is particularly true for mammals, where there has been no experimental work of any kind looking at the control of locomotion. The present experiment demonstrates that the Mongolian gerbil (Meriones unguiculatus) uses time-to-collision information to control deceleration as it runs towards a target. The development of this animal model will aid investigation of the neural circuitry underlying optic flow utilization in motor control.