[Evidence-based standardized nutrition protocol can shorten the time to full enteral feeding in very preterm/very low birth weight infants]. / åŸºäºŽå¾ªè¯çš„æ ‡å‡†åŒ–å–‚å »æ–¹æ¡ˆå¯ä»¥å¸®åŠ©æžæ—©äº§å„¿/æžä½Žå‡ºç”Ÿä½“é‡å„¿å°½æ—©è¾¾åˆ°å ¨è‚ é“å–‚å ».

OBJECTIVES: To investigate whether evidence-based standardized nutrition protocol can facilitate the establishment of full enteral nutrition and its effect on short-term clinical outcomes in very preterm/very low birth weight infants. METHODS: A retrospective analysis was performed on the medical data of 312 preterm infants with a gestational age of ≤32 weeks or a birth weight of <1 500 g. The standardized nutrition protocol for preterm infants was implemented in May 2020; 160 infants who were treated from May 1, 2019 to April 30, 2020 were enrolled as the control group, and 152 infants who were treated from June 1, 2020 to May 31, 2021 were enrolled as the test group. The two groups were compared in terms of the time to full enteral feeding, the time to the start of enteral feeding, duration of parenteral nutrition, the time to recovery to birth weight, the duration of central venous catheterization, and the incidence rates of common complications in preterm infants. RESULTS: Compared with the control group, the test group had significantly shorter time to full enteral feeding, time to the start of enteral feeding, duration of parenteral nutrition, and duration of central venous catheterization and a significantly lower incidence rate of catheter-related bloodstream infection (P<0.05). There were no significant differences between the two groups in the mortality rate and the incidence rate of common complications in preterm infants including grade II-III necrotizing enterocolitis (P>0.05). CONCLUSIONS: Implementation of the standardized nutrition protocol can facilitate the establishment of full enteral feeding, shorten the duration of parenteral nutrition, and reduce catheter-related bloodstream infection in very preterm/very low birth weight infants, without increasing the risk of necrotizing enterocolitis.

Mesenchymal stem cell-derived CCN2 promotes the proliferation, migration and invasion of human tongue squamous cell carcinoma cells.

Recent studies have demonstrated that mesenchymal stem cells (MSC) exhibit a tropism to tumors and form the tumor stroma. In addition, we found that MSC can secrete different types of factors. However, the involvement of MSC-derived factors in human tongue squamous cell carcinoma (TSCC) growth has not been clearly addressed. The CCN family includes multifunctional signaling molecules that affect the initiation and development events of various tumors. In our study, we report that CCN2/connective tissue growth factor (CTGF) was the most highly induced among the CCN family members in MSC that were co-cultured with TSCC cells. To evaluate the relationship between CCN2 and TSCC growth, we downregulated MSC-derived CCN2 expression with shRNA targeting CCN2 and found that MSC-secreted CCN2 promotes TSCC cell proliferation, migration and invasion. We also confirmed that MSC-derived CCN2 partially accelerated tumor growth in vitro. Taken together, these results suggest that MSC-derived CCN2 contributes to the promotion of proliferation, migration and invasion of TSCC cells and may be a possible therapy target in the future.

[Incidence of late-onset sepsis in very low birth weight and extremely low birth weight infants and risk factors for late-onset sepsis].

OBJECTIVE: To investigate the incidence of late-onset sepsis (LOS) in very low birth weight (VLBW) and extremely low birth weight (ELBW) infants in the neonatal intensive care unit (NICU) and the risk factors for LOS. METHODS: A retrospective analysis was performed for the clinical data of all VLBW and ELBW infants who were hospitalized in the NICU between January 2011 and December 2013. According to the presence or absence of LOS, these infants were divided into LOS group and non-LOS group. The incidence and mortality rates of LOS, common pathogenic bacteria, and risk factors for LOS were analyzed. RESULTS: Of the 226 VLBW and ELBW infants, 117 (51.8%) developed LOS, among whom 45 had a confirmed diagnosis of LOS and 72 had a clinical diagnosis of LOS. The LOS group had a significantly higher mortality rate than the non-LOS group [13.7% (16/117) vs 4.6% (5/109); P<0.05]. Bacterial culture found 51 strains of pathogenic bacteria, among which 32 (63%) were Gram-negative bacteria, 16 (31%) were Gram-positive bacteria, and 3 (6%) were fungi. The multivariate logistic regression analysis showed that gestational age, small for gestational age (SGA), duration of parenteral nutrition, peripherally inserted central catheter (PICC) placement, and mechanical ventilation were independent risk factors for LOS in VLBW and ELBW infants (OR=0.84, 1.59, 1.34, 3.11, and 4.55 respectively; P<0.05). CONCLUSIONS: LOS has high incidence and mortality rates in VLBW and ELBW infants. Common pathogenic bacteria of LOS are Gram-negative bacteria. Low gestational age, long duration of parenteral nutrition, SGA, PICC placement, and mechanical ventilation may increase the risk of LOS in VLBW and ELBW infants.

PDGF-D/PDGFRß promotes tongue squamous carcinoma cell (TSCC) progression via activating p38/AKT/ERK/EMT signal pathway.

Platelet-derived growth factor D (PDGF-D) signaling plays significant roles during the development and progression of human malignancies via interacting with the receptor of PDGF-D (PDGFR). Meanwhile, the majority of human tumor metastasis is closely associated with epithelial-mesenchymal transition (EMT). However, the underlying mechanism between PDGF-D/PDGFR signaling and EMT which involved in tumor metastasis remain dismal. This study aimed to investigate the role of PDGF-D signaling during EMT process of tongue squamous cell carcinoma (TSCC). In our study, the expression of PDGF-D and PDGFR were examined in primary TSCC samples and the expression of PDGF-D was also determined in TSCC cell lines. In addition, the correlation between PDGF-D expression and TSCC aggressive histopathological features was analyzed. Our results implied that upregulation of PDGFRß in UM1 cells induced with exogenous PDGF-D can remarkably promote tumor cells invasiveness; conversely, when using small interfering RNA (siRNA), the invasiveness can be severely prohibited. Furthermore, PDGF-D downstream signal molecules p38, AKT, ERK and EMT biomarkers (E-cadherin, N-cadherin, Vimentin and snail) were measured using Western blot. Our results showed that PDGF-D can induce p38, AKT and ERK phosphorylation; downregulate epithelial markers and upregulate mesenchymal markers. On the contrary, PDGFRß siRNA significantly prohibited p38, AKT and ERK phosphorylation; inhibited EMT process. Function analysis revealed that PDGFRß siRNA obviously interfered with UM1 cell migration and invasion, according to transwell and wound healing assay. In conclusion, this study suggested that EMT process can be triggered by the PDGF-D/PDGFRß axis in TSCC, and then involved in the tumor cell invasion via activation of p38/AKT/ERK/EMT pathway.

Overexpression of HMGA2 promotes tongue cancer metastasis through EMT pathway.

BACKGROUND: Metastasis to long distance organs is the main reason leading to morality of tongue squamous cell carcinoma (TSCC); however, the molecular mechanisms are still unknown. High mobility group AT-hook 2 (HMGA2) is highly expressed in multiple metastatic carcinomas, in which it contributes to cancer progression, metastasis and poor prognosis by upregulating Snail expression and inducing epithelial mesenchymal transition (EMT). This study focuses on investigating the role and mechanism of regulation of HMGA2 in the metastasis of TSCC. METHODS: HMGA2 mRNA and protein expression were examined in TSCC specimens by quantitative real-time polymerase chain reaction, western blotting and immunohistochemistry (IHC). Western blotting, IHC and immunofluorescence were also used to measure the expression and localization of EMT marker E-Cadherin and Vimentin both in TSCC cells and tissues. Knockdown assay was performed in vitro in TSCC cell lines using small interfering RNAs and the functional assay was carried out to determine the role of HMGA2 in TSCC cell migration and invasion. RESULTS: TSCC mRNA and protein expression were significantly up-regulated in tumor tissues when compared to adjacent non-tumor tissues, and the overexpression of HMGA2 was closely correlated with lymph nodes metastasis. Clinicopathological analysis indicated that HMGA2 expression was associated with clinical stage (P = 0.001), lymph node metastasis (P = 0.000), histological differentiation (P = 0.002) and survival (P = 0.000). Silencing the HMGA2 expression in Cal27 and UM1 resulted in the inhibition of cell migration and invasion, meanwhile down-regulation of HMGA2 impaired the phenotype of EMT in TSCC cell lines and tissues. The Multivariate survival analysis indicates that HMGA2 can be an independent prognosis biomarker in TSCC. CONCLUSION: Our findings demonstrate that HMGA2 promotes TSCC invasion and metastasis; additionally, HMGA2 is an independent prognostic factor which implied that HMGA2 can be a biomarker both for prognosis and therapeutic target of TSCC.

A classical but new kinetic equation for hydride transfer reactions.

A classical but new kinetic equation to estimate activation energies of various hydride transfer reactions was developed according to transition state theory using the Morse-type free energy curves of hydride donors to release a hydride anion and hydride acceptors to capture a hydride anion and by which the activation energies of 187 typical hydride self-exchange reactions and more than thirty thousand hydride cross transfer reactions in acetonitrile were safely estimated in this work. Since the development of the kinetic equation is only on the basis of the related chemical bond changes of the hydride transfer reactants, the kinetic equation should be also suitable for proton transfer reactions, hydrogen atom transfer reactions and all the other chemical reactions involved with breaking and formation of chemical bonds. One of the most important contributions of this work is to have achieved the perfect unity of the kinetic equation and thermodynamic equation for hydride transfer reactions.

Reverse facial artery flap to reconstruct the medium-sized defects in the middle facial region following cancer ablation.

This retrospective clinical study assessed the reliability of the reverse facial artery flap to reconstruct the medium-sized defects in the middle facial region following cancer ablation.Fifteen medium-sized defects were repaired with reversed facial artery flap following cancer surgery. The ages of the patients ranged from 2 to 69 years; 9 were male and 6 were female. The primary lesions included palate (5 cases), maxillary gingival (6 cases), cheek or buccal mucosa (3 case), and upper lip (1 case). The size of the skin paddle varied from 4.0 cm × 6.0 cm to 5.0 cm × 10.0 cm. Direct closure was achieved at all donor sites. Fourteen of the 15 flaps survived. No donor-site problems occurred. Two patients appeared to have temporary injury of facial nerve after operation. The follow-up period ranged from 8 to 36 months; 1 patient died as a result of local recurrence and 1 patient developed cervical recurrence.Consequently, it has been demonstrated that the reversed facial artery flap had reliable blood supply and can reliably and conveniently be used for reconstruction of the medium-sized defects, especially in the middle third of oral and maxillofacial region.

Knowledge mapping of diabetic foot research based on Web of Science database: A bibliometric analysis.

PURPOSE: To take a systematic bibliometric analysis and generate the knowledge mapping of diabetic foot research, basing on big data from Web of Science Core Collection (WoSCC) database. METHODS: Two authors retrieved the WoSCC independently, to obtain publications in field of diabetic foot. CiteSpace was used to detect the co-occurrence relationships of authors, keywords, institutions, and countries/regions, co-citation relationships of authors, references, and journals, and distribution of WoS category. RESULTS: A total of 10,822 documents were included, with 39,541 authors contributed to this field. "Armstrong DG," "Lavery LA," and "Lipsky BA" are the top 3 productive authors, and "Armstrong DG," "Boulton AJM," and "Lavery LA" were most commonly cited. The United States, England and China are the most productive countries, and Univ Washington, Univ Manchester and Harvard Univ published the largest quantity of articles. "Diabetes Care," "Diabetic Med," and "Diabetologia" are the most frequently cited journals, providing the greatest knowledge base. Clustering analysis of keywords co-occurrence map presented the following hotspots: #1 diabetic wound healing, #2 diabetic polyneuropathy, #3 plantar pressure, #4 diabetic foot infection, #5 endovascular treatment, and #6 hyperbaric oxygen therapy. CONCLUSION: This study performed a global overview of diabetic foot research using bibliometric and visualization methods, which would provide helpful references for researchers focusing on this area to capture the future trend.

Extracellular Vesicles: Emerging Roles in Developing Therapeutic Approach and Delivery Tool of Chinese Herbal Medicine for the Treatment of Depressive Disorder.

Extracellular vesicles (EVs) are lipid bilayer-delimited particles released by cells, which play an essential role in intercellular communication by delivering cellular components including DNA, RNA, lipids, metabolites, cytoplasm, and cell surface proteins into recipient cells. EVs play a vital role in the pathogenesis of depression by transporting miRNA and effector molecules such as BDNF, IL34. Considering that some herbal therapies exhibit antidepressant effects, EVs might be a practical delivery approach for herbal medicine. Since EVs can cross the blood-brain barrier (BBB), one of the advantages of EV-mediated herbal drug delivery for treating depression with Chinese herbal medicine (CHM) is that EVs can transfer herbal medicine into the brain cells. This review focuses on discussing the roles of EVs in the pathophysiology of depression and outlines the emerging application of EVs in delivering CHM for the treatment of depression.

A Simple Linear-Type Negative Permittivity Metamaterials Substrate Microstrip Patch Antenna.

A microstrip patch antenna (MPA) loaded with linear-type negative permittivity metamaterials (NPMMs) is designed. The simple linear-type metamaterials have negative permittivity at 1-10 GHz. Four groups of antennas at different frequency bands are simulated in order to study the effect of linear-type NPMMs on MPA. The antennas working at 5.0 GHz are processed and measured. The measured results illustrate that the gain is enhanced by 2.12 dB, the H-plane half-power beam width (HPBW) is converged by 14°, and the effective area is increased by 62.5%. It can be concluded from the simulation and measurements that the linear-type metamaterials loaded on the substrate of MAP can suppress surface waves and increase forward radiation well.

Different exercise therapies for treating heart failure: A protocol for overview of systematic reviews and network meta-analysis.

BACKGROUND: Exercise therapies has been shown to be safe and effective as a non-pharmacological management for treating heart failure, At the same time, many clinical trials, systematic review, and meta-analyses have demonstrated the advantages of exercise therapies in heart failure. However, the methodological quality of these systematic reviews and the differences in efficacy between different exercise modes are unclear. Therefore, this study intends to overview of systematic reviews and network meta-analysis of exercise therapies intervention in heart failure, and finally to rank the effects of exercise therapies in the intervention of heart failure, so as to provide certain reference for clinical decision-making. METHODS: From the seven databases: PubMed, EMBASE.com, Web of Science, the Cochrane Library, Chinese biomedical literature database (CBM), Chinese National Knowledge Infrastructure (CNKI), Wan fang Database, and Chongqing VIP (CQVIP) databases. To search for systematic or meta-analysis of different exercise therapies for heart failure from inception to August 2020. According to the inclusion criteria and exclusion criteria, the two researchers independently selected articles and extracted data. In case of differences, a third party shall be sought for settlement. The AMSTAR2 scale, PRISMA scale and GRADE were used to assess the quality and evidence grade of the literature. The eligible randomized controlled trials (RCTs) were selected from the included systematic reviews and updated RCTs from the above systematic reviews to August 2020. GRADE was used for the risk of bias of the included RCTs. Pairwise meta-analyses were performed using the random-effects model, and network meta-analysis of the included RCTs were performed the frequentist framework. All data analyses were completed in Stata 15.0. RESULTS: Finally, a total of 33 articles related to systematic review and meta-analysis were included, there are 28 articles in Chinese and 5 articles in English. The results of this overview and network meta-analysis will be submitted to a peer-reviewed journal for publication. CONCLUSION: This review will provide a comprehensive overview of existing systematic reviews of exercise therapies interventions for heart failure and provide recommendations for clinical practice or guidelines. PROTOCOL REGISTRATION: INPLASY202080118.

Application of Neurally Adjusted Ventilatory Assist in Premature Neonates Less Than 1,500 Grams With Established or Evolving Bronchopulmonary Dysplasia.

Background: Very low birth weight premature (VLBW) infants with bronchopulmonary dysplasia (BPD) often need prolonged respiratory support, which is associated with worse outcomes. The application of neurally adjusted ventilatory assist ventilation (NAVA) in infants with BPD has rarely been reported. This study investigated whether NAVA is safe and can reduce the duration respiratory support in VLBW premature infants with established or evolving BPD. Methods: This retrospective matched-cohort study included patients admitted to our NICU between April 2017 to April 2019 who were born at <32 weeks' gestation with birthweight of <1,500 g. The study groups (NAVA group) were infants who received NAVA ventilation as a sequel mode of ventilation after at least 2 weeks of traditional respiratory support after birth. The control group were preterm infants who required traditional respiratory support beyond first 2 weeks of life and were closely matched to the NAVA patients by gestational age and birthweight. The primary outcome was to compare the total duration of respiratory support between the NAVA group and the control group. The secondary outcomes were comparisons of duration of invasive and non-invasive support, oxygen therapy, length of stay, severity of BPD, weight gain and sedation need between the groups. Results: There were no significant differences between NAVA group and control group in the primary and most of the secondary outcomes (all P > 0.05). However, NAVA was well tolerated and there was a decrease in the need of sedation (p = 0.012) after switching to NAVA. Conclusion: NAVA, when used as a sequel mode of ventilation, in premature neonates <1,500 g with evolving or established BPD showed a similar effect compared to conventional ventilation in respiratory outcomes. NAVA can be safely used in this patient population and potentially can decrease the need of sedation.

Manipulation of visible-light polarization with dendritic cell-cluster metasurfaces.

Cross-polarization conversion plays an important role in visible light manipulation. Metasurface with asymmetric structure can be used to achieve polarization conversion of linearly polarized light. Based on this, we design a quasi-periodic dendritic metasurface model composed of asymmetric dendritic cells. The simulation indicates that the asymmetric dendritic structure can vertically rotate the polarization direction of the linear polarization wave in visible light. Silver dendritic cell-cluster metasurface samples were prepared by the bottom-up electrochemical deposition. It experimentally proved that they could realize the cross - polarization conversion in visible light. Cross-polarized propagating light is deflected into anomalous refraction channels. Dendritic cell-cluster metasurface with asymmetric quasi-periodic structure conveys significance in cross-polarization conversion research and features extensive practical application prospect and development potential.

[Combined repair of large defect caused by radical surgery of advanced tongue cancer with rib-major pectoralis myocutaneous flap carrying costal parietal pleura].

OBJECTIVE: To explore the clinical value and safety of using rib-major pectoralis myocutaneous flap carrying costal parietal pleura in combined repair of large soft and hard tissue defect caused by radical surgery of advanced tongue cancer. METHODS: Six patients with advanced tongue carcinoma involving the floor of mouth and mandible were performed combined radical neck dissection with glossectomy and mandibulectomy, which caused large soft and hard tissue defect. Six rib-major pectoralis myocutaneous flaps carrying costal parietal pleura were transferred for immediate repair of the large defects. The rib flaps were applied for the repair of mandible, and the major pectoralis myocutaneous flaps were applied for the reconstruction of tongue and floor of mouth. RESULTS: Six patients recovered well after operation. Six rib-major pectoralis myocutaneous flaps carrying costal parietal pleura survived well; the wounds of surgical incision of the oral cavity, neck, and chest healed up. The reconstructed tongue and the lower face appearance were satisfactory, the occlusion relationships were normal; the speaking as well as swallowing functions recovered. CONCLUSIONS: It's safe and reliable to use rib-major pectoralis myocutaneous flap carrying costal parietal pleura to repair large soft and hard tissue defect in oral and maxillofacial region. Opening pleural cavity and harvest costal parietal pleura would not influence patients' thoracic movement and breath function and would not cause other complications. It's simple and safe for harvesting the composite flap. Carrying costal parietal pleura assures the sufficient blood supply of rib in the composite flap.

Percutaneous sclerotherapy of arteriovenous malformations of the face using fibrin glue combined with OK-432 and bleomycin after embolisation.

Congenital arteriovenous malformations (AVM) in the maxillofacial region are rare, but potentially life-threatening, vascular lesions. Here we review our experience of 13 patients with AVM of the facial soft tissues who were treated using percutaneous sclerotherapy with fibrin glue combined with OK-432 and bleomycin after embolisation. The mean (range) follow-up was 27 (14-58) months. Three of the lesions were completely controlled, eight were nearly completely controlled, and the other two were partly controlled. Our experience is that percutaneous sclerotherapy of arteriovenous malformations of the face using fibrin glue combined with OK-432 and bleomycin after embolisation is safe and effective.

Guest-controlling effects on ER behaviors of beta-cyclodextrin polymer.

An effective and novel approach to obtaining electrorheological particles with high performance through the formation of host-guest complexes has been achieved. The significant preponderance of the host-guest complex formation is that the host structure can be controlled easily by adding different guests. Based on this point, six supramolecular complexes of beta-cyclodextrin cross-linking polymer with salicylic acid (beta-CDP-1), 5-chlorosalicylic acid (beta-CDP-2), 3,5-dichlorosalicylic acid (beta-CDP-3), 5-nitrosalicylic acid (beta-CDP-4), 3,5-dinitrosalicylic acid (beta-CDP-5), or 3-hydroxy-2-naphthoic acid (beta-CDP-6) particles were synthesized. The electrorheological yield stresses of the suspensions of these particles in silicone oil have been investigated under DC electric fields. It was found that the yield stress of the typical beta-CDP-1 ER fluid was 5.6 kPa in 4 kV/mm, which is much higher than that of pure beta-cyclodextrin polymer (beta-CDP), that of pure salicylic acid as well as that of the mixture of the host with the guest. It is clearly indicated that the formation of supramolecular complexes between beta-CDP and salicylic acid can enhance the ER properties of the host. The similar results for other supramolecular complexes with different guests have also been obtained under the same DC electric fields. The yield stress of supramolecular complexes is strongly affected by the structure of guests. Among the six investigated guests, 3-hydroxy-2-naphthoic acid gave the highest ER property having a yield stress of 9.8 kPa under 4 kV/mm DC while cross-linked with beta-CDP to form beta-CDP-6. The yield stress of beta-CDP-6 was significantly increased by 72% in comparison with that of the pure beta-CDP. However, the yield stress of beta-CDP-1-5 slightly increased by 34-41% as compared with that of the pure beta-CDP. The achieved results indicate that the ER effect of host-guest complexes can be greatly affected by the changes of the tremendous guest structure, whereas the slight guest structural transposition, such as altering different groups of a guest, can only obtain the adjacent electrorheological behavior. The dielectric properties of these host-guest complexes also proved that the ER effect can be affected by the properties of guest.

[Morphology Manifestation of Bone Marrow Cells in 155 Newly- Diagnosed Patients with POEMS Syndrome].

OBJECTIVE: To investigate the morphological manifestation of bone marrow cells in newly-diagnosed patients with POEMS syndrome. METHODS: The bone marrow cells in 155 patients with POEMS syndrome were classified and counted by OLYMPUS BX51 microscope, and the abnormal morphology of bone marrow cells was observed. RESULTS: The count of plasma cells with normal morphology was 83.9% (130/155), the count of plasma cells with abnormal morphology (< 5 percent) was 12.3% (19/155), the count of plasma cells with obvious abnormal morphology (> 10 percent) was 3.8% (6/155) in patients with POEMS syndrome. CONCLUSION: The morphology of plasma cells in the most patients with the POEMS syndrome are normal, the minor patients of the POEMS syndrome have little abnormal plasma cell morphology, the extremely few patients showed obvious morphological abnormality in the bone marrow plasma cells. The higher proportion of plasma cells, the more easily and more abnormal plasma cells will be found.

Electrorheological fluids based on glycerol-activated titania gel particles and silicone oil with high yield strength.

This article describes an electrorheological (ER) fluid based on glycerol-activated titania organic-inorganic hybrid gel particles and silicone oil with high yield strength. Based on a physical picture of a water-activated ER system, glycerol that has a high dielectric constant and boiling point is in situ prepared in the amorphous titania gel during the sol-gel processing. A small amount of ionic surfactant hexadecyltrimethylammonium bromide (CTAB) is employed to enhance charge carriers in particles. FTIR and XRD techniques are used to determine the nature and structure of the hybrid gel. Rheology test results show that a large static yield stress greater than 12.6 kPa is obtained when 3 kV/mm dc electric field is applied. This value is close to the value predicted by H. Conrad (MRS Bull. 8 (1998) 35) in theory. Furthermore, dynamic shear stress as a function of shear rate and temperature is also investigated. This ER fluid exhibits strong temperature dependence and a wide working temperature range from 0 to 120 degrees C, while its leaking current density is still low. More interesting is that the glycerol content is demonstrated to have an influence on ER effect and temperature dependence. Measurement of the dielectric properties of ER fluids shows enhancement of the dielectric constant and dielectric loss due to addition of glycerol and a regular dependence of them on temperature, which well explains the strong ER effect.

Reflectance speckle of retinal nerve fiber layer reveals axonal activity.

PURPOSE: This study investigated the retinal nerve fiber layer (RNFL) reflectance speckle and tested the hypothesis that temporal change of RNFL speckle reveals axonal dynamic activity. METHODS: RNFL reflectance speckle of isolated rat retinas was studied with monochromatic illumination. A series of reflectance images was collected every 5 seconds for approximately 15 minutes. Correlation coefficients (CC) of selected areas between a reference and subsequent images were calculated and plotted as a function of the time intervals between images. An exponential function fit to the time course was used to evaluate temporal change of speckle pattern. To relate temporal change of speckle to axonal activity, in vitro living retina perfused at a normal (34°C) and a lower (24°C) temperature, paraformaldehyde-fixed retina, and retina treated with microtubule depolymerization were used. RESULTS: RNFL reflectance was not uniform; rather nerve fiber bundles had a speckled texture that changed with time. In normally perfused retina, the time constant of the CC change was 0.56 ± 0.26 minutes. In retinas treated with lower temperature and microtubule depolymerization, the time constants increased by two to four times, indicating that the speckle pattern changed more slowly. The speckled texture in fixed retina was stationary. CONCLUSIONS: Fixation stops axonal activity; treatments with either lower temperature or microtubule depolymerization are known to decrease axonal transport. The results obtained in this study suggest that temporal change of RNFL speckle reveals structural change due to axonal activity. Assessment of RNFL reflectance speckle may offer a new means of evaluating axonal function.