Is a Vitrimer with a High Glass Transition Temperature Available? A Case Study on Rigid Polyimides Cross-Linked with Dynamic Ester Bonds.

Vitrimers, possessing associative covalent adaptable networks, are cross-linked polymers exhibiting malleable (glass-like) feature and recyclable and reprocessable (thermoplastics-like) properties. The dynamic behaviors of vitrimer are dependent on both chain/molecular mobility (glass transition temperature, Tg) and dynamic bond-exchanging reaction rate (topology freezing transition temperature, Tv). This work aims on probing the effect of high Tg on the stress relaxation and physical recyclability of vitrimers, employing a polyimide cross-linked with dynamic ester bonds (Tg: 310 °C) as the example. Due to its high Tg and chain rigidity, the cross-linked polyimide does not exhibit a high extent of stress relaxation behavior at 320 °C (10 °C above its Tg), even though the temperature is much higher than the hypothetical Tv. While raising the processing temperature to 345 °C, the cross-linked polyimide exhibits a stress relaxation time of about 3300 s and physical malleability. Nevertheless, side reactions may occur in the recycling and reprocessing process under the harsh condition (high temperature and high pressure) to alter the thermal properties of the recycled sample. The diffusion control plays a critical role on the topography transition of a vitrimer having a high Tg. The Tg ceiling is noticeable for developments of vitrimers.

Impact of pre-existing mental health disorders on the receipt of guideline recommended cancer treatments: A systematic review.

OBJECTIVE: Disparities in cancer outcomes for individuals with pre-existing mental health disorders have already been identified, particularly for cancer screening and mortality. We aimed to systematically review the influence on the time from cancer diagnosis to cancer treatment, treatment adherence, and differences in receipt of guideline recommended cancer treatment. METHODS: We included international studies published in English from 1 January 1995 to 23 May 2022 by searching MEDLINE, Embase, and APA PsycInfo. RESULTS: This review identified 29 studies with 27 being published in the past decade. Most studies focused on breast, non-small cell lung and colorectal cancer and were of high or medium quality as assessed by the Newcastle Ottawa Scale. All studies were from high-income countries, and mostly included patients enrolled in national health insurance systems. Five assessed the impact on treatment delay or adherence, and 25 focused on the receipt of guideline recommended treatment. 20/25 studies demonstrated evidence that patients with pre-existing mental health disorders were less likely to receive guideline recommended therapies such as surgery or radiotherapy. In addition, there was a greater likelihood of receiving less intensive or modified treatment including systemic therapy. CONCLUSIONS: Across different cancer types and treatment modalities there is evidence of a clear disparity in the receipt of guideline recommended cancer treatment for patients with pre-existing mental health disorders. The effect of pre-existing mental health disorders on treatment delay or adherence is under-researched. Future research needs to include low- and middle-income countries as well as qualitative investigations to understand the reasons for disparities in cancer treatment.

Efficacy of levocetirizine in isolated rat tracheal smooth muscle.

Histamine receptor-1 (H1) antagonists like levocetirizine are frequently used nowadays to treat rhinitis patients who experience rhinorrhea and sneezing. The trachea may be affected by the H1 antagonist when it is used to treat nasal symptoms, either orally or through inhalation. The purpose of this study was to ascertain in vitro effects of levocetirizine on isolated tracheal smooth muscle. As a parasympathetic mimetic, methacholine (10-6 M) causes contractions in tracheal smooth muscle, which is how we tested effectiveness of levocetirizine on isolated rat tracheal smooth muscle. We also tested the drug's impact on electrically induced tracheal smooth muscle contractions. The impact of menthol (either before or after) on the contraction brought on by 10-6 M methacholine was also investigated. According to the results, the addition of levocetirizine at concentrations of 10-5 M or more caused a slight relaxation in response to methacholine's 10-6 M contraction. Levocetirizine could prevent spike contraction brought on by electrical field stimulation (EFS). As the concentration rose, it alone had a neglect effect on the trachea's basal tension. Before menthol was applied, levocetirizine might have also inhibited the function of the cold receptor. According to this study, levocetirizine might potentially impede the parasympathetic function of the trachea. If levocetirizine was used prior to menthol addition, it also reduced the function of cold receptors.

In Vitro Bioactivity and Antibacterial Effects of a Silver-Containing Mesoporous Bioactive Glass Film on the Surface of Titanium Implants.

Peri-implantitis is defined as a bacterial infection-induced inflammation and suppuration of soft and hard tissues surrounding a dental implant. If bacteria further invade the alveolar bone, they can easily cause bone loss and even lead to the early failure of a dental implant surgery. In the present study, an 80SiO2-15CaO-5P2O5 mesoporous bioactive glass film system containing 1, 5, and 10 mol% of silver was prepared on titanium implant discs (MBG-Ag-coated Ti) using sol-gel and spin coating methods. The wettability and adhesion strength of the films were evaluated using contact angle measurements and adhesion strength tests, respectively. The phase composition, chemical bonding, morphology, and oxidation states of the films were analyzed via X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). In vitro bioactivity analysis of the films was performed by immersion in a simulated body fluid (SBF) for 24 h. Disk diffusion tests were performed on the early colonizing bacteria Aggregatibacter actinomycetemcomitans and Streptococcus mutans to evaluate the antibacterial ability of the films. A silver-containing mesoporous bioactive glass film with excellent biocompatibility and antibacterial properties was successfully prepared.

Transmission dynamics of COVID-19 among index case family clusters in Beijing, China.

The outbreak of coronavirus disease-2019 (COVID-19) impacts public health dramatically around the world. The demographic characteristics, exposure history, dates of illness onset and dates of confirmed diagnosis were collected from the data of 24 family clusters from Beijing. The characteristics of the cases and the estimated key epidemiologic time-to-event distributions were described. The basic reproductive number (R0) was calculated. Among 89 confirmed COVID-19 patients from 24 family clusters, the median age was 38.0 years and 43.8% were male. The median of incubation period was 5.08 days (95% confidence interval (CI) 4.17-6.21). The median of serial interval was 6.00 days (95% CI 5.00-7.00). The basic reproductive number (R0) was 2.06 (95% CI 2.02-2.08). The median of onset-to-care-seeking days and the median of onset-to-hospital admission days were significantly reduced after 23 January 2020, which implied the enhanced public health awareness among families. With epidemic containment measures in place, the results can inform health authorities about possible extent of epidemic transmission within families. Furthermore, following initiation of interventions, public health measures are not only important for curbing the epidemic spread at the community level but also improve health seeking behaviour at the individual level.

Age-standardized expected years of life lost: quantification of cancer severity.

BACKGROUND: The critical implications of the expected years of life lost (EYLL) index of cancer for health policy assessments have been largely overlooked. We advocate to standardize life lost indices. METHODS: Using the Taiwan Cancer Registry database as an example, we calculated the EYLL and the age-standardized EYLL to facilitate comparisons among cancer types (a total of 903,935 patients from the database). The International Cancer Survival Standard was used for calculating age-standardized EYLL. RESULTS: Pancreatic cancer is the most severe cancer in Taiwan, with the greatest age-standardized EYLL for the men (15.6 years) and women (18.0 years) as well as for the men and women combined (16.6 years). Negative correlations were observed between unstandardized EYLL of cancer and mean age at diagnosis. CONCLUSIONS: The unstandardized EYLL represents an overall assessment of disease burden, whereas the age-standardized EYLL is a suitable measure of disease severity. We suggest that both measures be incorporated into routine annual reports of cancer statistics alongside the usual incidence and mortality rates and their age-standardized counterparts.

Comparative Effectiveness and Safety of Antithrombotic Therapy in Atrial Fibrillation Patients Presenting with Acute Coronary Syndrome or Percutaneous Coronary Intervention.

BACKGROUND: There remains insufficient evidence to determine the optimal antithrombotic strategy in atrial fibrillation (AF) patients presenting with acute coronary syndrome (ACS) or percutaneous coronary interventions (PCIs), especially in Asian populations. OBJECTIVES: This study aimed to examine the real-world patterns of antithrombotic treatment among these patients and to compare the effectiveness and safety of different antithrombotic regimens. METHODS: A retrospective cohort study was conducted in AF patients presenting with a new ACS or PCI during 2006/1/1-2016/4/1. Three antithrombotic regimens were compared: dual antiplatelet therapy (DAPT, as the reference group), triple therapy (TT: DAPT plus an oral anticoagulant), and dual therapy (DT: single antiplatelet plus an oral anticoagulant). The outcomes of interest were major adverse cardiac and cerebrovascular events (MACCEs) and bleeding. Treatment effect was estimated using a Cox proportional hazards model. Inverse probability of treatment weighting was used to balance baseline characteristics among comparison groups. RESULTS: Overall, 532 patients were included. At discharge from the index hospitalization, DAPT was the most common antithrombotic therapy, followed by TT and DT. No significant difference in MACCEs was found among the different antithrombotic regimens. However, DT was associated with a lower risk of any bleeding [adjusted hazard ratio 0.20 (95% confidence interval, 0.06-0.75)] than DAPT. CONCLUSIONS: In the study population, DAPT was the most commonly prescribed antithrombotic regimen for cardio-cerebrovascular disease prevention. The effectiveness outcomes were comparable across different antithrombotic strategies. The lower risk of bleeding with DT compared with DAPT warrants further investigation.

Development of single-chain variable fragments (scFv) against influenza virus targeting hemagglutinin subunit 2 (HA2).

Influenza A viruses (IAV) are widespread in birds and domestic poultry, occasionally causing severe epidemics in humans and posing health threats. Hence, the need to develop a strategy for prophylaxis or therapy, such as a broadly neutralizing antibody against IAV, is urgent. In this study, single-chain variable fragment (scFv) phage display technology was used to select scFv fragments recognizing influenza envelope proteins. The Tomlinson I and J scFv phage display libraries were screened against the recombinant HA2 protein (rHA2) for three rounds. Only the third-round elution sample of the Tomlinson J library showed high binding affinity to rHA2, from which three clones (3JA18, 3JA62, and 3JA78) were chosen for preparative-scale production as soluble antibody by E. coli. The clone 3JA18 was selected for further tests due to its broad affinity for influenza H1N1, H3N2 and H5N1. Simulations of the scFv 3JA18-HA trimer complex revealed that the complementarity-determining region of the variable heavy chain (VH-CDR2) bound the stem region of HA. Neutralization assays using a peptide derived from VH-CDR2 also supported the simulation model. Both the selected antibody and its derived peptide were shown to suppress infection with H5N1 and H1N1 viruses, but not H3N2 viruses. The results also suggested that the scFvs selected from rHA2 could have neutralizing activity by interfering with the function of the HA stem region during virus entry into target cells.

Rostral Intralaminar Thalamic Deep Brain Stimulation Triggered Cortical and Hippocampal Structural Plasticity and Enhanced Spatial Memory.

BACKGROUND/AIMS: Rostral intralaminar thalamic nucleus (ILN) has been shown to modulate cognition through indirect connection with the hippocampus and prefrontal cortex. We explored the effects of deep brain stimulation (DBS) to the rostral ILN on spatial memory acquisition, brain neuronal activation and cortical and hippocampal synaptic changes in rats. METHODS: The Morris water maze (MWM) task was used to evaluate the spatial memory of the rats. The expression of c-fos, an immediate early gene, was used to identify neural activation in the cerebral cortex and hippocampus. Synaptic changes in the somatosensory cortical and hippocampal neurons were explored with dendritic spine analysis following Golgi-Cox staining. RESULTS: Our results showed that a barrage of DBS to the rostral ILN of normal rats significantly shortened their escape latency in MWM compared with sham-stimulated and untreated control rats. Rats with enhanced spatial memory had more c-fos immunoreactive cells in layer IV of the somatosensory cortex. Layer III cortical and CA1 hippocampal pyramidal neurons showed over 50% increase of dendritic spines, while only the proximal apical dendrites of layer V cortical pyramidal neurons had more dendritic spines. CONCLUSIONS: Rostral ILN-DBS activated neurons in the cerebral cortex and triggered cortical and hippocampal structural plasticity in association with spatial memory enhancement.

A comparison of the stages at which cancer is diagnosed in physicians and in the general population in Taiwan.

BACKGROUND: Previous investigations have reported that physicians tend to neglect their own health care; however, they may also use their professional knowledge and networks to engage in healthier lifestyles or seek prompt health services. We sought to determine whether the stage at which cancer is diagnosed differs between physicians and nonphysicians. METHODS: We conducted a nationwide matched cohort study over a period of 14 years in Taiwan. We accessed data from two national databases: the National Health Insurance Research Database and the Taiwan Cancer Registry File. We collected data on all patients with the 6 most common cancers in Taiwan (hepatoma, lung, colorectal, oral, female breast and cervical cancer) from 1999 to 2012. We excluded patients less than 25 years of age, as well as those with a history of organ transplantation, cancer or AIDS. We used propensity score matching for age, sex, residence and income to select members for the control (nonphysicians) and experimental (physicians) groups at a 5:1 ratio. We used χ(2) tests to analyze the distribution of incident cancer stages among physicians and nonphysicians. We compared these associations using multinomial logistic regression. We performed sensitivity analyses for subgroups of doctors and cancers. RESULTS: We identified 274,003 patients with cancer, 542 of whom were physicians. After propensity score matching, we assigned 536 physicians to the experimental group and 2680 nonphysicians to the control group. We found no significant differences in cancer stage distributions between physicians and controls. Multinomial logistic regression and sensitivity analyses showed similar cancer stages in most scenarios; however, physicians had 2.64-fold higher risk of having stage IV cancer at diagnosis in cases of female breast and cervical cancer. INTERPRETATION: In this cohort of physicians in Taiwan, cancer was not diagnosed at earlier stages than in nonphysicians, with the exception of stage IV cancer of the cervix and female breast.

Applying the transtheoretical model to promote functional fitness of community older adults participating in elastic band exercises.

AIMS: The transtheoretical model was applied to promote behavioural change and test the effects of a group senior elastic band exercise programme on the functional fitness of community older adults in the contemplation and preparation stages of behavioural change. BACKGROUND: Forming regular exercise habits is challenging for older adults. The transtheoretical model emphasizes using different strategies in various stages to facilitate behavioural changes. DESIGN: Quasi-experimental design with pre-test and post-tests on two groups. METHODS: Six senior activity centres were randomly assigned to either the experimental or control group. The data were collected during 2011. A total of 199 participants were recruited and 169 participants completed the study (experimental group n = 84, control group n = 85). The elastic band exercises were performed for 40 minutes, three times per week for 6 months. The functional fitness of the participants was evaluated at baseline and at the third and sixth month of the intervention. Statistical analyses included a two-way mixed design analysis of variance, one-way repeated measures analysis of variance and an analysis of covariance. RESULTS: All of the functional fitness indicators had significant changes at post-tests from pre-test in the experimental group. The experimental group had better performances than the control group in all of the functional fitness indicators after three months and 6 months of the senior elastic band exercises. CONCLUSION: The exercise programme provided older adults with appropriate strategies for maintaining functional fitness, which improved significantly after the participants exercising regularly for 6 months.

A nurse-family partnership intervention to increase the self-efficacy of family caregivers and reduce catheter-associated urinary tract infection in catheterized patients.

The purpose of this study was to evaluate the effects of a nurse-family partnership model on the self-efficacy of family caregivers (FCs) and the incidence of catheter-associated urinary tract infection (CAUTI) among patients. A randomized controlled study was conducted. We recruited 61 patients and their FCs, who were randomly divided into an experimental group (n = 30) and a control group (n = 31). In the experimental group, the main caregivers comprised a nurse-family partnership, whereas the control participants received routine care. The findings were as follows: (i) the incidence of CAUTI was lower in the experimental group than in the control group (20% vs. 38.8%), but the difference was not statistically significant; and (ii) no significant difference emerged for reported Caregiver Self-Efficacy Score between the two groups. The nursing team and FCs must become partners in cooperative caregiving to enhance the quality of patient care.

Morphological changes of cortical pyramidal neurons in hepatic encephalopathy.

BACKGROUND: Hepatic encephalopathy (HE) is a reversible neuropsychiatric syndrome associated with acute and chronic liver diseases. It includes a number of neuropsychiatric disturbances including impaired motor activity and coordination, intellectual and cognitive function. RESULTS: In the present study, we used a chronic rat HE model by ligation of the bile duct (BDL) for 4 weeks. These rats showed increased plasma ammonia level, bile duct hyperplasia and impaired spatial learning memory and motor coordination when tested with Rota-rod and Morris water maze tests, respectively. By immunohistochemistry, the cerebral cortex showed swelling of astrocytes and microglia activation. To gain a better understanding of the effect of HE on the brain, the dendritic arbors of layer V cortical pyramidal neurons and hippocampal CA1 pyramidal neurons were revealed by an intracellular dye injection combined with a 3-dimensional reconstruction. Although the dendritic arbors remained unaltered, the dendritic spine density on these neurons was significantly reduced. It was suggested that the reduction of dendritic spines may be the underlying cause for increased motor evoked potential threshold and prolonged central motor conduction time in clinical finding in cirrhosis. CONCLUSIONS: We found that HE perturbs CNS functions by altering the dendritic morphology of cortical and hippocampal pyramidal neurons, which may be the underlying cause for the motor and intellectual impairments associated with HE patients.

Characteristics, survival, and related factors of newly diagnosed colorectal cancer patients refusing cancer treatments under a universal health insurance program.

BACKGROUND: Colorectal cancer is the third most commonly diagnosed cancer worldwide. Few studies have addressed the causes and risks of treatment refusal in a universal health insurance setting. METHODS: We examined the characteristics and survival associated with treatment refusal in patients with newly diagnosed colorectal cancer in Taiwan during 2004-2008. Treatment refusal was defined as not undergoing any cancer treatment within 4 months of confirmed cancer diagnosis. Patient data were extracted from four national databases. Factors associated with treatment refusal were identified through logistic regression using the generalized estimating equation method, and survival analysis was performed using the Cox proportional hazards model. RESULTS: Of the 41,340 new colorectal cancer cases diagnosed, 3,612 patients (8.74%) refused treatment. Treatment refusal rate was higher in patients with less urbanized areas of residence, lower incomes, preexisting catastrophic illnesses, cancer stages of 0 and IV, and diagnoses at regional and district hospitals. Logistic regression analysis revealed that patients aged >75 years were the most likely to refuse treatment (OR, 1.87); patients with catastrophic illnesses (OR, 1.66) and stage IV cancer (OR, 1.43) had significantly higher refusal rates. The treatment refusers had 2.66 times the risk of death of those who received treatment. Factors associated with an increased risk of death in refusers included age ≥ 75 years, insured monthly salary ≥ 22,801 NTD, low-income household or aboriginal status, and advanced cancer stage (especially stage IV; HR, 11.33). CONCLUSION: Our results show a lower 5-year survival for colorectal patients who refused treatment than for those who underwent treatment within 4 months. An age of 75 years or older, low-income household status, advanced stages of cancer, especially stage IV, were associated with higher risks of death for those who refused treatment.

Social welfare utilization and needs of older adults in Taiwan: survey research.

BACKGROUND: The demand for long-term care for older adults has escalated sharply. A good policy dedicated to the welfare of older adults has improved their quality of life. The purpose of this study was to explore the social welfare utilization and needs of older adults and compare their differences among age groups, genders, and functional dependency levels. METHODS: Three hundred eighty-four stratified, random-sampled Taiwanese community-dwelling older adults were recruited for this survey research. Participants rated their utilization of and needs for the 30 social welfare services provided by the government on a Likert-type scale. RESULTS: The most widely used and needed social welfare services by the older adults were senior monetary stipend and a subsidy for the national health insurance premium. Young-old, male, and functionally independent older adults had more knowledge of the social welfare services than their counterparts. CONCLUSIONS: While designing a comprehensive social welfare system, differing needs of different age groups, genders, and functional dependency levels should be taken into consideration.

Establishment of a competitive ELISA for detection of florfenicol antibiotic in food of animal origin.

Florfenicol (FF) is a synthetic antibiotic with a broad antibacterial spectrum and the high therapeutic effectiveness that has been developed specifically for veterinary use. Obviously, FF adulterated in animal supplies is one of essential global concerns. A competitive ELISA for the detection of florfenicol in food of animal origin (swine, chicken, and fish) is described. Influence of immunoconjugate structure on the assay sensitivity and specificity was investigated. The new ELISA showed much lower than the MRPLs for FF at 100-3,000 mg kg(-1) in the European Communities and the sensitivity of our ELISA method was superior to that described in other reports. According to the test preparation record, the limit of detection of the developed ELISA performed on meat species was 0.3 µg kg(-1) (IC50 value 1.9 µg kg(-1)). The method developed permits FF concentrations to be determined in the range 0.3-24.3 µg kg(-1). A low cross-reactivity with florfenicol amine (FFA), thiamphenicol (TAP), and chloramphenicol (CAP) was displayed (16.2%, 9.5%, and 9.4%, respectively). Recovery in different food samples (swine, chicken, and fish) averages between 87-115%. The method can be applied for inspection of animal supplies for trace florfenicol residues.

Psychological and socioeconomic health of community-dwelling older adults.

Different dimensions of health are intertwined. The purposes of this study were: (1) to investigate the psychological and socioeconomic health status of community-dwelling older adults in Taiwan, and (2) to compare the psychological and socioeconomic health differences among people of different age groups, gender, marital status, and exercise habits. Using stratified random sampling, 384 Taiwanese community-dwelling older adults were recruited for this survey research. Based on the Health Model of Older Adults, seven constructs were measured: (1) psychological health: sleep quality, emotional health, cognitive functioning, and health promotion behaviors; (2) socioeconomic health: social engagement, social support, and financial status. Results showed that most participants were in a good state of psychological and socioeconomic health, except that 38.02% of them suffered from sleep disruptions, and the majority of them were not involved in any social group, nor engaged in any volunteer work. Young-old older adults had better psychological and socioeconomic health than middle-old and old-old older adults. Male older adults had better psychological health than female older adults; however, they had less social engagement and social support than female older adults. Married older adults and exercisers performed better in most of the psychological and socioeconomic health indicators than single/widowed older adults and non-exercisers.

Caring for students with type 1 diabetes: school nurses' experiences.

This qualitative study used a Husserlian phenomenological approach to obtain an understanding of the essences of five experienced Taiwanese school nurses' lived experience of caring for students with type 1 diabetes mellitus (T1DM). Audio-recorded, semi-structured, in-depth interviews were conducted. Data analysis entailed a modified method from Colaizzi. Four intertwined themes were discovered: (a) I try to put myself in the parents' and students' shoes, (b) I am not a diabetes expert, (c) managing T1DM requires teamwork, and (d) caring for students with T1DM is a struggle with practical limitations. The findings show that these school nurses encountered many challenges as they implemented their roles and responsibilities in caring for students with T1DM. The findings suggest that increasing school nurses' competence in caring for students with T1DM and developing effective strategies to overcome the challenges faced may be useful. Multidisciplinary teamwork could benefit the diabetes management activities in school settings.

Integrated ground and vertical measurement techniques to characterize overhead atmosphere: Case studies of local versus transboundary pollution.

Much attention has been found to the long-range transport (LRT) of air pollutants and their adverse effects on downwind air qualities resulting from the Chinese haze, which frequently occurs in association with winter monsoon. This study integrates ground-based measurements, unmanned aerial vehicles (UAVs), and model simulations to characterize the meteorological, chemical, and particulate matter (PM) properties comprehensively for the events that were LRT or local pollution (LP) dominated in northern Taiwan during the wintertime of 2017. During the two types of episodes, various approaches were made to investigate the vertical mixing conditions and PM properties with UAV flights. A confined and PM accumulated feature near ground level with a temperature inversion was found during the LP event. In contrast, a vertically homogeneous atmospheric structure with strong winds was suggested during the LRT event. Independent measurements of criteria air pollutants, meteorological variables, volatile organic compounds (VOCs), and micropulse lidar (MPL) made at the ground level were closely supported by the vertical measurements. When synchronizing all these observational and numerical tools in a three-dimensional manner, the characterization of air masses and possible origins of pollution, such as LP vs. LRT, has now become more versatile and capable of gaining a complete picture of atmospheric conditions that define air quality.

Active endocytosis and microtubule remodeling restore compressed pyramidal neuron morphology in rat cerebral cortex.

Previous studies have shown that compression alone reduced the thickness of rat cerebral cortex and apical dendritic lengths of pyramidal neurons without apparent cell death. Besides, decompression restored dendritic lengths at different degrees depending on duration of compression. To understand the mechanisms regulating dendritic shortening and lengthening upon compression and decompression, we applied transmission electron microscopy to examine microtubule and membrane structure of pyramidal neurons in rat sensorimotor cortex subjected to compression and decompression. Microtubule densities within apical dendritic trunks decreased significantly and arranged irregularly following compression for a period from 30 min to 24 h. In addition, apical dendritic trunks showed twisted contour. Two reasons are accounted for the decrease of microtubule density within this period. First, microtubule depolymerized and resulted in lower number of microtubules. Second, the twisted membrane widened the diameters of apical dendritic trunks, which also caused a decrease in microtubule density. Interestingly, these compression-induced changes were quickly reversed to control level following decompression, suggesting that these changes were accomplished passively. Furthermore, microtubule densities were restored to control level and the number of endocytotic vesicles significantly increased along the apical dendritic membrane in neurons subjected to 36 h or longer period of compression. However, decompression did not make significant changes on dendrites compressed for 36 h, for they had already shown straight appearance before decompression. These results suggest that active membrane endocytosis and microtubule remodeling occur in this adaptive stage to make the apical dendritic trunks regain their smooth contour and regular microtubule arrangement, similar to that of the normal control neurons.