[Brain death: from the transformation of medical concept to the change of medical practice]

The implementation of death determination by clinicians usually involves three steps: learning the concept of death, mastering the skills of death determination, and recording the results of death determination. Each process needs to be changed with the progress of medical science. The transformation of brain death concept is the establishment and formation of the latest cognition of "irreversible brain function", which needs to be completed based on the theoretical learning of recognized standards. The transformation of brain death determination is the learning and mastering of the latest skills of brain death determination, which requires relearning and retraining based on special technologies. The transformation of brain death determination is the habit formation of standardized records of brain death judgement results, which needs to be completed based on the continuous improvement of case quality control. The gradual advancement of the three steps will accelerate the process of determining brain death in China.

[The effect of Ba Duan Jin on the balance of community-dwelling older adults: a cluster randomized control trial]

Objective: To assess the effectiveness of a 6-month Ba Duan Jin exercise program in improving the balance of community-dwelling older adults. Methods: A two arms, parallel-group, cluster randomized controlled trial was conducted in 1 028 community residents aged 60-80 years in 40 communities in 5 provinces of China. Participants in the intervention group (20 communities, 523 people) received Ba Duan Jin exercise 5 days/week, 1 hour/day for 6 months, and three times of falls prevention health education, and the control group (20 communities, 505 people) received falls prevention health education same as the intervention group. The Berg balance scale (BBS) score was the leading outcome indicator, and the secondary outcome indicators included the length of time of standing on one foot (with eyes open and closed), standing in a tandem stance (with eyes open and closed), the closed circle test, and the timed up to test. Results: A total of 1 028 participants were included in the final analysis, including 731 women (71.11%) and 297 men (28.89%), and the age was (69.87±5.67) years. After the 3-month intervention, compared with the baseline data, the BBS score of the intervention group was significantly higher than the control group by 3.05 (95%CI: 2.23-3.88) points (P<0.001). After the 6-month intervention, compared with the baseline data, the BBS score of the intervention group was significantly higher than the control group by 4.70 (95%CI: 4.03-5.37) points (P<0.001). Ba Duan Jin showed significant improvement (P<0.05) in all secondary outcomes after 6 months of exercise in the intervention group compared with the control group. Conclusions: This study showed that Ba Duan Jin exercise can improve balance in community-dwelling older adults aged 60-80. The longer the exercise time, the better the improvement.

[Clinical effects of retrograde anterolateral thigh flaps in repairing anterior knee joint wounds under the concept of precise flap surgery]

Objective: To introduce the methods of retrograde anterolateral thigh flaps in repairing anterior knee joint wounds under the concept of precise flap surgery and to explore the clinical effects. Methods: A retrospective observational study was conducted. From August 2014 to March 2022, 7 patients with anterior knee joint wounds were treated with retrograde anterolateral thigh flap under the guidance of the concept of precise flap surgery in the 920th Hospital of Joint Logistic Support Force of PLA. Among them, 6 were males and 1 was female, aged 36 to 66 years. The sizes of wounds were 7 cm×5 cm to 15 cm×11 cm after debridement. All the patients were performed with computed tomography angiography (CTA), the donor and recipient sites were evaluated according to the precise flap surgery method, and the optimal pedicle, perforator, and pivot of flaps were chosen. The flap sizes were 10 cm×6 cm to 20 cm×9 cm, and all the donor sites of flaps were sutured directly. The consistency of the intraoperative exploration with preoperative CTA was observed. The flap survival and occurrence of complications were observed after surgery. The color, appearance, texture, and occurrence of complications were followed up. At the last follow-up, the blood supply of flaps was evaluated using the blood circulation evaluation indicators of Chinese Medical Association Hand Surgery Branch's trial criteria for digital replantation function evaluation, and the function of knee joint was evaluated using knee joint scoring system of hospital for special surgery. Results: The flap condition of the intraoperative exploration was completely consistent with that of preoperative CTA. The flaps survived completely after surgery in 6 patients, while necrosis at the edge of the flap occurred in 1 patient, which healed after dressing change. All the flaps were hyperperfused after surgery, and the color of the flaps gradually became normal after 1 week. Follow-up of 7 to 44 months showed that the color, appearance, and texture were well in all the patients, while local osteomyelitis at the proximal tibia occurred in 1 patient. At the last follow-up, all the 7 patients had excellent blood circulation; the function score of knee joint was 69 to 91, which was evaluated as excellent in 3 cases, good in 3 cases, and fair in 1 case. Conclusions: The retrograde anterolateral thigh flap has large variations, and the application of precise flap surgery method can accurately understand the variations before surgery, guide the design and cutting of the flaps, thus achieving precise repair of anterior knee joint wounds, with good repair outcome.

[Cardiac amyloidosis: pathological classification and clinical analysis of 48 cases]

Objective: To investigate the histological features and clinical manifestations in different types of cardiac amyloidosis to improve diagnostic accuracy. Methods: The histopathological features and clinical manifestations of 48 patients diagnosed with cardiac amyloidosis by Congo red stain and electron microscopy through endomyocardial biopsy were collected in West China Hospital of Sichuan University from January 2018 to December 2021. Immunohistochemical stains for immunoglobulin light chains (κ and λ) and transthyretin protein were carried out, and a review of literature was made. Results: The patients age ranged from 42 to 79 years (mean 56 years) and the male to female ratio was 1.1 to 1.0. The positive rate of endomyocardial biopsy was 97.9% (47/48), which was significantly higher than that of the abdominal wall fat (7/17). Congo red staining and electron microscopy were positive in 97.9% (47/48) and 93.5% (43/46), respectively. Immunohistochemical stains showed 32 cases (68.1%) were light chain type (AL-CA), including 31 cases of AL-λ type and 1 case of AL-κ type; 9 cases (19.1%) were transthyretin protein type (ATTR-CA); and 6 cases (12.8%) were not classified. There was no significant difference in the deposition pattern of amyloid between different types (P>0.05). Clinical data showed that ATTR-CA patients had less involvement of 2 or more organs and lower N-terminal pro-B-type natriuretic peptide (NT-proBNP) than the other type patients (P<0.05). The left ventricular stroke volume and right ventricular ejection fraction of ATTR-CA patients were better than the other patients (P<0.05). Follow-up data of 45 patients was obtained, and the overall mean survival time was 15.6±2.0 months. Univariate survival analysis showed that ATTR-CA patients had a better prognosis, while cardiac amyloidosis patients with higher cardiac function grade, NT-proBNP >6 000 ng/L, and troponin T >70 ng/L had a worse prognosis (P<0.05). Multivariate survival analysis showed that NT-proBNP and cardiac function grade were independent prognostic factors for cardiac amyloidosis patients. Conclusions: AL-λ is the most common type of cardiac amyloidosis in this group. Congo red staining combined with electron microscopy can significantly improve the diagnosis of cardiac amyloidosis. The clinical manifestations and prognosis of each type are different and can be classified based on immunostaining profile. However, there are still a few cases that cannot be typed; hence mass spectrometry is recommended if feasible.

Risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis patients

OBJECTIVE

To investigate the risk factors of left ventricular diastolic dysfunction in maintenance hemodialysis (MHD) patients.

METHOD

We retrospectively collected data from 363 hemodialysis patients who were on dialysis for at least 3 months at January 1, 2020. According to the echocardiogram results, these patients were divided into left ventricular diastolic dysfunction (LVDD) group and non-LVDD group. The differences in basic data, cardiac structure and functiona between the two groups were analyzed. Logistic regression analysis was used to analyze the risk factors of cardiac diastolic dysfunction in MHD patients.

RESULTS

Compared with the non-LVDD group, patients in the LVDD group were older, with an increased proportion of coronary heart disease, more prone to chest tightness, shortness of breath. Simultaneously, they had a significantly increased (p < 0.05) proportion of cardiac structural abnormalities such as left ventricular hypertrophy, left heart enlargement and systolic dysfunction. Multivariate logistic regression analysis showed that the risk of LVDD was significantly increased in elderly MHD patients older than 60 years (OR = 3.86, 95%CI 1.429-10.429), and left ventricular hypertrophy was also significantly associated with LVDD (OR = 2.227, 95% CI 1.383-3.586).

CONCLUSION

According to research, both age and left ventricular hypertrophy are risk factors for LVDD in MHD patients. It is recommended that early intervention for LVDD should be implemented to improve the quality of dialysis and reduce the incidence of cardiovascular events in MHD patients.

[Current situation and advancement of brain death determination in China]

China's "Criteria and practical guidance for determination of brain death (BD)" based on medicine was launched eight years ago. After joining the writing and publishing work of "The World Brain Death Project-Determination of Brain Death/Death by Neurologic Criteria", China has accelerated the process of internationalization. For this reason, the author expressed his own opinions on the related work progress and existing problems. (1) Although the criteria of BD in different countries are different due to various national conditions, cultures, religions and laws, we can seek common ground while reserving differences, such as the unification of the minimum criteria and the choice of confirmatory tests. (2) Although there are differences in the executive force of BD evaluation among countries around the world due to whether legislation or not, all walks of life and the public can respect the development of medicine. (3) Although there are still life support and organ donation problems to be solved after the determination of BD, they will be solved one by one through medical practice. In a word, we believe that the specification of BD determination in China will continue to advance orderly and rapidly.

[Effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy for screening imported patients with COVID-19 in Xiamen]

Objective: To analysis effectiveness of the "14 plus 7 day quarantine" and "nucleic acid plus total antibody testing" strategy (combined screening strategy) for screenin the imported patients with COVID-19 in Xiamen. Methods: The study populations were overseas travelers arriving in Xiamen from March 17 to December 31, 2020, and overseas travelers who had quarantine outside Xiamen for less than 21 days from July 18 to December 31, 2020. Data were collected and analyzed on the timing of detection, pathways, and test results of the imported patients with COVID-19 after implementing combined screening strategy. Results: A total of 304 imported patients with COVID-19 were found from 174 628 overseas travelers and 943 overseas travelers from other cities. A total of 163 cases (53.6%) were diagnosed by multitime, multisite intensive nucleic acid testing after positive finding in total antibody testing. Among them, 27 (8.9%) were first positive for nucleic acid in 14 plus 7 day quarantine and 136 were first positive for nucleic acid in 14-day quarantine. Only 8 of these individuals were tested positive for nucleic acid after positive total antibody testing. The other 128 individuals were tested positive for nucleic acid after being negative for average 2.3 times (maximum of 6 times). Aditional 155 cases might be detected by using the combined "14 plus 7 day quarantine" and " nucleic acid plus total antibody testing" strategy compared with "14-day quarantine and nucleic acid testing" strategy, accounting for 51.0% of the total inbound infections. So the combined screening strategy doubled the detection rate for imported patients with COVID-19. No second-generation case caused by overseas travelers had been reported in Xiamen as of February 26, 2021. Conclusions: Xiamen's combined screening strategy can effectively screen the imported patients with COVID-19 who were first positive for nucleic acid after 14 day quarantine. Compared with "14 day quarantine and nucleic acid testing", the combined screening strategy improved detection rate and further reduced the risk of the secondary transmission caused by the imported patients with COVID-19.

Stem cells in the treatment of renal fibrosis: a review of preclinical and clinical studies of renal fibrosis pathogenesis

Renal fibrosis commonly leads to glomerulosclerosis and renal interstitial fibrosis and the main pathological basis involves tubular atrophy and the abnormal increase and excessive deposition of extracellular matrix (ECM). Renal fibrosis can progress to chronic kidney disease. Stem cells have multilineage differentiation potential under appropriate conditions and are easy to obtain. At present, there have been some studies showing that stem cells can alleviate the accumulation of ECM and renal fibrosis. However, the sources of stem cells and the types of renal fibrosis or renal fibrosis models used in these studies have differed. In this review, we summarize the pathogenesis (including signaling pathways) of renal fibrosis, and the effect of stem cell therapy on renal fibrosis as described in preclinical and clinical studies. We found that stem cells from various sources have certain effects on improving renal function and alleviating renal fibrosis. However, additional clinical studies should be conducted to confirm this conclusion in the future.

[Preliminary audiological evaluation of the SoundBite bone conduction devices in adults with single-sided deafness]

Objective: The auditory deficits of single-sided deafness (SSD) can be treated with a novel intra-oral device, SoundBite, which delivers sound by applying vibratory signal to the teeth. The purpose of this study was to evaluate the efficacy and benefit of the bone conduction device for Chinese adults with SSD. Methods: Eighteen patients aged 19-66 yrs with acquired, permanent sensorineural SSD and no current treatment by any other devices for SSD, were recruited in a prospective controlled, nonrandomized, unblinded study. They were requested the continually daily wear of the new device over a 30-day free trial period. The intra-oral hearing device was placed around two maxillary teeth and was similar to a small partial denture or retainer. The audiological tests included pure tone air conduction thresholds, monosyllable word recognition score (WRS) in quiet and sentence reception thresholds in noise (via CMNmatrix test). The benefit was determined with the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Speech, Spatial and Qualities of Hearing Scale (SSQ) questionnaire. Results: The monosyllable WRS and the 50% threshold of signal-to-noise ratio (SNR₅₀) were significantly better in all aided conditions. The head shadow effect, assessed by the SNR₅₀ via CMNmatrix test improved an average of 2.6 dB after 30 days' wearing compared with unaided condition (P<0.001). The APHAB scores improved (P<0.05) for all subjects for the Global and Ease of Communication, Reverberation, Background Noise subscales. The SSQ scores improved (P<0.05) for all subjects for Speech, Spatial and Qualities of Hearing subscales. Conclusion: The SoundBite is a good alternative to the well-established implantable bone conduction devices in patients with SSD. An improvement in listening ability in noise and quiet as well as a decrease of the head shadow effect is validated as the expected.

[Rapid identification of Cordyceps and its products using DNA barcoding method]

Cordyceps is one of the most valuable traditional Chinese medicines. There are various counterfeits in markets because of high price and limited output. In this study,116 Cordyceps,146 hosts and 29 related products were collected and detected by using normal DNA barcoding technology and specific PCR method. The results indicated that Cordyceps and its adulterants could be distinguished from each other through DNA barcoding technology based on ITS and COⅠsequences. Two pairs specific primers ITSSF1/ITSSR1 and ITSSF2/ITSSR2 were developed to amplify 297 bp and 136 bp ITS regions of Cordyceps sinensis,respectively. It could be used to identify C. sinensis specifically and rapidly. Furthermore,specific primers ITSSF1/ITSSR1 and ITSSF2/ITSSR2 combined with ITS and COⅠsequences could differentiate powder Cordyceps from fermentation mycelia and could identify related products. Therefore,the method developed from this study could be applied to identify the powder of Cordyceps from fermentation mycelia and related products efficiently.

[Introduction of papillomavirus rapid interface for modelling and economics (PRIME) and an example of China's data analysis]

Cervical cancer has become an important disease that jeopardizes women's health, causing hundreds of thousands of new cases annually. Human papillomavirus (HPV) is the leading cause for cervical cancer. Since the world's first HPV vaccine was licensed in 2006, 92 countries around the world have introduced them in national immunization programs. The WHO recommends that scientific economic evaluation should be achieved before the introduction, but this is more difficult for low-and middle-income countries. Therefore, this article introduces a mathematical model recommended by WHO in 2014 to quickly and easily accomplish economic evaluation of HPV vaccine -the PRIME, and take the China's 2018 data published by International Agency for Research on Cancer (IARC) as an example. The evaluation result shows that the introduction of HPV vaccine in Chinese 12-year-old women is cost-effective.

[Rapid identification of Gekko gecko by loop-mediated isothermal amplification based on 12S rRNA sequence]

Gekko gecko (Tokay Gecko) is a valuable traditional Chinese medicine. In this study, the loop-mediated isothermal amplification (LAMP) technique was introduced for visual rapid identification of G. gecko from adulterants. A total of sixty-five 12S rRNA sequences of fourteen species of G. gecko and its adulterants were obtained. The results showed that G. gecko could be identified from its adulterants through BLAST analysis based on 12S rRNA regions. The 12S rRNA sequences of ten batches of G. gecko were conserved. There were only two haplotypes and three variation sites in the available regions for primers design. Six specific LAMP primers were successfully designed online based on 12S rRNA sequences. The visual rapid detection of G. gecko could be achieved with the optimized conditions (64 °C for 1 h and 80 °C for 5 min). And the required minimal template concentration was 5 μg·L⁻¹ while conventional PCR with 0.5 mg·L⁻¹. Consequently, the LAMP method established from this study was rapid, specific, highly sensitive, and simple. It could be applied to detect G. gecko from its adulterants efficiently.

[Measurement of uterine volume in patients with endometriosis and its clinical significance]

Objective: To measure the uterine volume by ultrasonic imaging in nullipara patients with endometriosis and analyze its clinical significance. Methods: From July 1st, 2016 to August 1st, 2017, 107 cases of nullipara patients with endometriosis hospitalized in Peking University First Hospital were selected as endometriosis group. Among 107 cases, 59 cases were in proliferative phase of menstrual cycle, 48 cases were in secretory phase; and 10 cases had an abortion history.Totally 101 cases of patients without endometriosis operated for other benign disease during the same period were chosen as the control group. All patients underwent laparoscopic surgery, and the diagnosis was confirmed by pathology. The uterine size was measured by transvaginal or transrectal color Doppler ultrasound, and the uterine volume was calculated according to the known formula. Results: The uterine volume of the endometriosis group [(69±26) cm(3)] was larger than that of the control group [(54±18) cm(3), P<0.01]. In the endometriosis group, the uterine volume of patients with pregnant history [(78±34) cm(3)] was larger than that of patients without pregnant history [(68±25) cm(3)]. The endometrial thickness in endometriosis group was higher than that of the control group [(9.1±3.5) versus (7.8±2.9) mm, P<0.05], and positively correlated with the uterine volume (r=0.39, P<0.05). The hemoglobin in endometriosis group was lower than that in the control group [(124±12) versus (131±10) g/L, P<0.01], and was negatively correlated with the uterine volume in the two groups (r(endometriosis)=-0.12, r(control)=-0.21; both P<0.05).The uterine volume of dysmenorrhea patients in the endometriosis group [(73±28) cm(3)] was greater than that of patients without dysmenorrhea [(62±19) cm(3), P<0.01]; both uterine volumes of patients with and without dysmenorrhea in endometriosis group were larger than those of patients with or without dysmenorrhea in the control group (P<0.05). The degree of dysmenorrhea in endometriosis group was positively correlated with the uterine volume (r=0.20, P=0.042). The uterine volume of stage Ⅳendometriosis patients [(79±30) cm(3)] was greater than that of stage Ⅲ patients in endometriosis group [(58±14) cm(3), P<0.01]. Conclusion: Patients with endometriosis are of increased uterine volume, which may be related to dysmenorrhea, menorrhagia and infertility.

Abnormality of intestinal cholesterol absorption in ApcMin/+ mice with colon cancer cachexia

Colorectal cancer syndrome has been one of the greatest concerns in the world, particularly in developed countries. Several epidemiological studies have shown that dyslipidemia may be associated with the progression of intestinal cachexia, but there is little research on the function of the small intestine, which is involved in blood lipid metabolism, in dyslipidemia. In the present study, we aimed to explore the function of intestinal cholesterol absorption in the Apc^Min/+ mouse model using an intestinal lipid absorption test. We found that both triglyceride (TG) and total cholesterol (TC) uptake were inhibited in the intestine of Apc^Min/+ mice with age and the intestinal peroxisome proliferator-activated receptor α (PPARα) downregulated the processes of β-oxidation, oxidative stress response, and cholesterol absorption in APC-deficient mice. In addition, reduced expression levels of farnesoid X receptor (FXR) and apical sodium-dependent bile acid transporter (ASBT) indicated that bile acid metabolism might be associated with intestinal cholesterol absorption in Apc^Min/+ mice. Thus, our data suggested that the intestine plays an essential role in cholesterol uptake and that bile acid metabolism seems to cause a decrease in intestinal cholesterol uptake in Apc^Min/+ mice.

[Analysis of clinical characteristics and outcomes of mechanically ventilated patients with anti-N-methyl-D-aspartate receptor encephalitis]

Objective: To explore the clinical characteristics and long-term outcomes of mechanically ventilated patients with anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis. Methods: In this observational study, patients with anti-NMDAR encephalitis were enrolled, who were admitted into Xuanwu Hospital of Capital Medical University from Jan 2012 to Jun 2015.All patients accepted tumor screening, symptomatic therapy, and immunotherapy.Outcomes were assessed by modified Rankin Scale (mRS) after immunotherapy every 6 months, and mRS 0-2 was defined as favorable outcome.The differences of clinical manifestations, auxiliary examinations, and outcomes between mechanical ventilation (MV) group and no MV group were analyzed. Results: Fifty-six patients (mean age 28±12 years, range 12 to 58 years) were enrolled, and 28 were male.MV group included 16 (28.6%) patients.Five female patients were diagnosed with ovarian teratoma.After 6 months, 50 patients (89.3%) had favorable outcomes, mortality was 0.The proportions of patients being female, with ovarian teratoma, conscious disturbance, dysautonomia, accepting plasmapheresis, immunodepressant treatment, admitted into neuro-critical care unit in MV group were significant higher than those in no MV group.The duration of illness prior to MV was 10-73 days (mean 33±19 days). The period of MV was 3-154 days (mean 46±41 days). There was no significant difference in the period of using MV among different outcome groups.After 6-48 months' follow-up, 6 patients (10.7%) relapsed, with 1 patient in MV group (1/16, 6.3%), 5 patients in no MV group (5/40, 12.5%). The relapses and long-term outcomes were not significant different between MV group and no MV group. Conclusions: The condition of mechanically ventilated patients with Anti-NMDAR encephalitis is severe, and the treatment is difficult. However, after active combined immunotherapy and life support, majority of these patients could get good long-term outcomes.

[The impact of male circumcision on the natural history of genital HPV infection: a prospective cohort study]

Objective: To analyze the correlation between circumcision and incidence and clearance of male genital HPV infection. Methods: From May to July 2014, 18-55 year old men who had sexual behavior history were recruited from the general population in Liuzhou, Guangxi to set up a cohort. Totally, 113 circumcised and 560 uncircumcised men were enrolled and interviewed using a questionnaire (including information on demographic characteristics and sexual behaviors), then they were followed-up with 6-month interval for 2 times. On each visit, specimens of male external genitalia were collected and genotyped for HPV DNA. The differences of incidence and clearance of genital HPV infections between circumcised and uncircumcised men were analyzed by Log-rank test. Cox regression was used to analyze the relationship between circumcision and incidence and clearance of HPV infection. Results: The median age (P(25), P(75)) of circumcised and uncircumcised men were 28 (24, 35) and 32 (24, 31), respectively. The incidences of any HPV infections were 9.1 (95%CI: 2.4-15.7) and 8.4 (95% CI: 5.6-11.2) per 1 000 person-months (χ(2)=0.10, P=0.758), respectively. The clearance of circumcised men [136.3 (95%CI: 70.0-202.7) per 1 000 person-months] was higher than that in uncircumcised men [89.6 (95%CI: 65.9-113.3) per 1 000 person-months] (χ(2)=8.19, P=0.004). In multivariate COX regression analysis, compared with uncircumcised men, circumcised men had higher possibility to clear any HPV infections (HR: 2.41, 95%CI: 1.30-4.46). Compared with men having one sexual partner, people having more than 4 sexual partners had lower possibility to clear any HPV infections (HR: 0.49, 95%CI: 0.25-0.96). Compared with 18-25 years old men, men aged 26-35 years old had higher possibility to clear high-risk HPV infections (HR: 2.14, 95%CI: 1.08-4.23). Conclusion: Circumcised and uncircumcised men had similar incidence of genital HPV infection, whereas, men conducted circumcision and having fewer sexual partners could increase the clearance of genital HPV infections.

[Clinical efficacy of acute intraoperative encephalocele prevention strategy for severe traumatic brain injury]

Objective: To explore the clinical efficacy of prevention strategy for acute intraoperative encephalocele of patients with severe traumatic brain injury (sTBI). Methods: A total of 173 patients with sTBI, who treated in Emergency Neurosurgery Department of Shandong University Qilu Hospital from January, 2011 to September, 2015 were collected and divided into research group and control group, according to their therapeutic strategy.The clinical data during hospitalization and prognosis 1 year after injury was analyzed retrospectively to clarify the effect of acute encephalocele prevention strategy. Results: There were no statistically significant differences in sex, age, preoperative Glasgow coma scale score and imaging type of lesion between patients from the two groups.The highest intraoperative intracranial pressure in the research group and control group were (35.71±4.13) mmHg and(34.85±3.81) mmHg, respectively.The acute encephalocele incidence of the research group (7 cases, 6.5%) was significantly lower than that of the control group (13 cases, 19.7%) (P<0.01). Subgroup analysis showed that the incidence of acute encephalocele in patients with only unilateral lesions was low (1.3%), while higher (19.4%) in patients with both unilateral lesions and other secondary lesions or diffuse brain swelling.The prognosis of the patients was evaluated by Glasgow Outcome Scale according to the follow-up 1 year after injury, and it was suggested that the percentage of patients with good outcome in the research group (62 cases, 57.9%) was remarkably higher than that in the control group (26 cases, 39.4%) (P=0.018). Conclusions: For sTBI patients with high risk of acute encephalocele, prevention strategy was found to be able to retard the progression of delayed hematoma and diffuse brain swelling, prevent the acute encephalocele during operation, and then significantly improve the prognosis.

PPAR‑γ agonist rosiglitazone protects rat peritoneal mesothelial cells against peritoneal dialysis solution‑induced damage

Long-term peritoneal dialysis (PD) leads to ultrafiltration failure (UFF). Peritoneal mesothelial cells, which form the innermost monolayer of the peritoneal cavity, have been shown to regulate various responses, including inflammation, in UFF. The present study was designed to investigate the effect of the peroxisome proliferator‑activated receptor‑γ (PPAR‑γ) agonist, rosiglitazone, on peritoneal dialysis solution (PDS)‑induced injuries in rat peritoneal mesothelial cells (RPMCs). RPMCs were cultured for different durations and with different concentrations of PDS. The gene expression levels of aquaporin‑1 (AQP‑1) and zonula occluden‑1 (ZO‑1) were determined using reverse transcription‑quantitative polymerase chain reaction analysis. The protein levels of AQP‑1, ZO‑1 and PPAR‑γ were measured using western blot analysis. Interleukin (IL)‑6 and IL‑8 were detected using ELISA. The RPMCs were damaged by stimulation with 4.25% PDS for 72 h. The expression levels of AQP‑1 and ZO‑1 were increased, and the secretion of IL‑6 and IL‑8 were decreased by rosiglitazone. The use of the PPAR‑γ inhibitor, GW‑9662, completely prevented the effects of rosiglitazone. These results indicated that PDS exposure stimulated an inflammatory response in the RPMCs. The PPAR‑γ activator, rosiglitazone, appeared to relieve the injury by inhibiting inflammation, and regulating the expression of AQP‑1 and ZO‑1, however further investigations are required to elucidate the potential underlying mechanism.

Atorvastatin alleviates renal ischemia-reperfusion injury in rats by promoting M1-M2 transition

Acute kidney injury (AKI) often occurs as a result of ischemia-reperfusion (IR). Previous studies have demonstrated that inflammation is an important contributor to AKI. Atorvastatin (ATO) possesses anti‑inflammatory properties and has been demonstrated to exert protective effects against renal IR injury (IRI). However, the underlying mechanism requires further study. In the present study, a rat model of renal IRI was successfully established. Consistent with the results of a previous study, ATO significantly attenuated IRI, which was supported by a decrease in serum creatinine and an increase in creatinine clearance rate, as well as alleviated pathological alterations in renal tubular cells. There are two types of activated macrophages: Proinflammatory M1 and anti‑inflammatory M2 macrophages, which have been demonstrated to exert contributory and protective effects on IRI, respectively. The present study demonstrated that treatment with ATO significantly decreased M1 macrophage density and increased M2 macrophage density, as compared with the IR group. In addition, it is well known that M1 macrophages can be induced by T helper 1 cytokines, including tumor necrosis factor (TNF)‑α and interferon (IFN)‑γ, whereas M2 macrophages can be induced by peroxisome proliferator-activated receptor (PPAR)‑γ. The present study indicated that ATO treatment significantly decreased the expression levels of TNF‑α and IFN‑γ, and increased PPAR‑γ expression. In conclusion, ATO may ameliorate renal IRI by promoting M1‑M2 transition. Furthermore, ATO‑mediated macrophage polarization in rats with renal IRI may be associated with the downregulation of TNF‑α and IFN‑γ, and the upregulation of PPAR-γ.

Involvement of peroxisome proliferator activated receptor-γ in the anti-inflammatory effects of atorvastatin in oxygen-glucose deprivation/reperfusion-stimulated RAW264.7 murine macrophages

Ischemia-reperfusion (I/R) injury is important in the pathogenesis and/or progression of various diseases, including stroke, cardiovascular disease and acute renal injury. Increasing evidence indicates that atorvastatin exerts protective effects in I/R injury-associated diseases; however, the underlying mechanisms remain to be fully elucidated. In the present study, oxygen-glucose deprivation (OGD)/reperfusion-stimulated. RAW264.7 murine macrophages served as a model of I/R injury. The knockdown of peroxisome proliferator activated receptor-γ (PPARγ) expression in these cells increased OGD/reperfusion-induced expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ), and enhanced OGD/reperfusion-induced downregulation of the expression of cluster of differentiation (CD) 206, at the mRNA and protein levels. Conversely, overexpression of PPARγ significantly attenuated OGD/reperfusion-induced alterations in the expression of iNOS, TNF-α, IFN-γ and CD206 at the mRNA and protein levels. Notably, atorvastatin inhibited OGD/reperfusion-induced iNOS expression and reversed OGD/reperfusion-induced downregulation of the expression of CD206 and PPARγ at the mRNA and protein levels. The results of the present study indicate that atorvastatin exhibits significant anti-inflammatory effects in OGD/reperfusion-stimulated RAW264.7 cells, possibly via PPARγ regulation. The findings of the present study may reveal a novel mechanism underlying the protective effects of atorvastatin in I/R injury-associated diseases.

Levels of vitamin D receptor and CYP24A1 in patients with end-stage renal disease

OBJECTIVE

This study was performed to detect the expression of vitamin D receptor (VDR) and cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1) in 24 end stage renal disease (ESRD) patients and 24 healthy controls.

METHOD

In this study, 24 ESRD patients and 24 healthy controls were included.

RESULTS

In our study, the levels of VDR in patients with ESRD were reduced when compared with those from healthy controls (5.20±0.32 vs 8.59±1.03; P<0.01). However, the levels of CYP24A1 in ESRD patients were increased than those from healthy controls (50.18±21 vs 7.78±1.31; P<0.01). Correlation analysis showed that VDR levels were negatively correlated with CYP24A1 (r=-0.723; P<0.01).

CONCLUSION

VDR levels were reduced and CYP24A1 levels were increased in patients with ESRD, and VDR levels were negatively correlated with CYP24A1.

Label-free aptasensor for adenosine deaminase sensing based on fluorescence turn-on

A label-free and fluorescence turn-on aptamer biosensor has been developed for the detection of adenosine deaminase (ADA) activity with simplicity and selectivity. Adenosine aptamer will form a tight stem-loop structure upon binding with adenosine. In the absence of ADA, only a small quantity of picagreen intercalates into the stem section of aptamer, resulting in a low fluorescence of picagreen when excited at 490 nm. Interestingly, after the addition of ADA, adenosine is hydrolyzed to inosine, and the released aptamer forms double-stranded DNA (dsDNA) with its complementary single-stranded DNAc, followed by the intercalation of picagreen to dsDNA. When the solution is excited, picagreen emits strong green fluorescence. The increased fluorescence intensity of picagreen is dependent on the concentration of ADA. The detection limit of the ADA is determined to be 2 U L(-1), which is lower than ADA cutoff value (4 U L(-1)) in the clinical requirement and more sensitive than most of the reported methods. Compared to other previous ADA sensors, the assay is not only label-free but also a turn-on signal, and possesses properties of lower cost and simpler detection system. Furthermore, this label-free strategy is also applicable to the assay of other enzymes and screening of corresponding inhibitors.

Sodium salicylate suppresses GABAergic inhibitory activity in neurons of rodent dorsal raphe nucleus

Sodium salicylate (NaSal), a tinnitus inducing agent, can activate serotonergic (5-HTergic) neurons in the dorsal raphe nucleus (DRN) and can increase serotonin (5-HT) level in the inferior colliculus and the auditory cortex in rodents. To explore the underlying neural mechanisms, we first examined effects of NaSal on neuronal intrinsic properties and the inhibitory synaptic transmissions in DRN slices of rats by using whole-cell patch-clamp technique. We found that NaSal hyperpolarized the resting membrane potential, decreased the input resistance, and suppressed spontaneous and current-evoked firing in GABAergic neurons, but not in 5-HTergic neurons. In addition, NaSal reduced GABAergic spontaneous and miniature inhibitory postsynaptic currents in 5-HTergic neurons. We next examined whether the observed depression of GABAergic activity would cause an increase in the excitability of 5-HTergic neurons using optogenetic technique in DRN slices of the transgenic mouse with channelrhodopsin-2 expressed in GABAergic neurons. When the GABAergic inhibition was enhanced by optical stimulation to GABAergic neurons in mouse DRN, NaSal significantly depolarized the resting membrane potential, increased the input resistance and increased current-evoked firing of 5-HTergic neurons. However, NaSal would fail to increase the excitability of 5-HTergic neurons when the GABAergic synaptic transmission was blocked by picrotoxin, a GABA receptor antagonist. Our results indicate that NaSal suppresses the GABAergic activities to raise the excitability of local 5-HTergic neural circuits in the DRN, which may contribute to the elevated 5-HT level by NaSal in the brain.

Altered neuronal intrinsic properties and reduced synaptic transmission of the rat's medial geniculate body in salicylate-induced tinnitus

Sodium salicylate (NaSal), an aspirin metabolite, can cause tinnitus in animals and human subjects. To explore neural mechanisms underlying salicylate-induced tinnitus, we examined effects of NaSal on neural activities of the medial geniculate body (MGB), an auditory thalamic nucleus that provides the primary and immediate inputs to the auditory cortex, by using the whole-cell patch-clamp recording technique in MGB slices. Rats treated with NaSal (350 mg/kg) showed tinnitus-like behavior as revealed by the gap prepulse inhibition of acoustic startle (GPIAS) paradigm. NaSal (1.4 mM) decreased the membrane input resistance, hyperpolarized the resting membrane potential, suppressed current-evoked firing, changed the action potential, and depressed rebound depolarization in MGB neurons. NaSal also reduced the excitatory and inhibitory postsynaptic response in the MGB evoked by stimulating the brachium of the inferior colliculus. Our results demonstrate that NaSal alters neuronal intrinsic properties and reduces the synaptic transmission of the MGB, which may cause abnormal thalamic outputs to the auditory cortex and contribute to NaSal-induced tinnitus.

First Report of Leaf Disease on Cinnamomum subavenium Caused by Colletotrichum fioriniae in China

Cinnamomum subavenium Miq. (Lauraceae) is a subtropical arbor plant widely distributed in southwest China. It has a long history of cultivation and has been widely used in traditional Chinese medicine, food flavors, and industrial materials. In August 2010, a serious leaf disease was observed on wild Cinnamomum subavenium growing in Gutianshan Nature Reserve, Zhejiang, China. Lesions were approximately 1.0 cm in diameter and the margin of the lesions was light to dark brown and the middle was gray to pale yellowish. Necrotic lesions were surface disinfected with 1% sodium hypochlorite for 1 min and 70% ethanol for 3 min, and isolations were made from lesion edges onto potato dextrose agar (PDA). Three plants were tested and a fungus was consistently isolated from lesions. Colonies of this fungus on PDA were at first gray becoming pinkish gray with age, with salmon pink conidial masses, and the reverse of the colony was pink. The growth rate was 10.82 to 11.95 mm per day (average = 11.58 ± 0.25, n = 6) on PDA at 25°C. Conidia were oblong or cylindrical with acute ends, occasionally guttulate, hyaline, 7.5 to 14.5 × 2.5 to 4.3 μm (average = 11.25 ± 0.5 × 3.4 ± 0.4, n = 30). These characteristics matched the description of Colletotrichum fioriniae (Marcelino & Gouli) R.G. Shivas & Y.P. Tan (2). DNA was extracted from one isolate and the rDNA-internal transcribed spacer (ITS) region was amplified and sequenced using primers ITS1 and ITS4 (1). The ITS sequence of the isolate (GenBank Accession No. JN208890) shared 100% identity to the holotype of C. fioriniae (Accession No. EF464594). The pathogenicity of C. fioriniae on Cinnamomum subavenium was confirmed through inoculation. Three freshly harvested, healthy leaves were washed under running tap water, immersed in 5% sodium hypochlorite for 3 min and 70% ethanol for 1 min, rinsed three times in sterilized water, and finally dried with sterilized tissue paper. Plant leaves were inoculated with a concentration of 2.5 × 10⁶ spores/ml. Sterilized water was used for controls. All the leaves inoculated with C. fioriniae were symptomatic with round to elliptical lesions with a brown margin 14 days postinoculation. The fungus, reisolated from symptomatic leaf tissue, had the same morphological and cultural characteristics of C. fioriniae. Although C. gloeosporioides has been reported from several species in the genus Cinnamomum ( http://nt.ars-grin.gov/fungaldatabases/ ), to our knowledge, this is the first report of leaf disease on Cinnamomum subavenium caused by a Colletotrichum species. References: (1) H. Prihastuti et al. Fungal Divers. 39:89, 2009. (2) R. G. Shivas and Y. P. Tan. Fungal Divers. 39:111, 2009.

Valproate versus diazepam for generalized convulsive status epilepticus: a pilot study

BACKGROUND AND PURPOSE

Evidence-based data to guide the management of status epilepticus (SE) after failure of primary treatment are still scarce and the alternate needs to be found when phenytoin (PHT) is not available or contraindicated. Comparison of intravenous (IV) valproate (VPA) and diazepam (DZP) infusion has not been conducted in adults with SE. This prospective randomized controlled trial is thus designed to evaluate the relative efficacy and safety of IV VPA and continuous DZP infusion as second-line anticonvulsants.

METHODS

After failure of first-line anticonvulsants treatment, patients with generalized convulsive status epilepticus (GCSE) were randomized to receive either IV VPA or continuous DZP infusion. Primary outcome was the proportion of patients with effective control. Side effects were also evaluated.

RESULTS

There were 66 cases enrolled, with the mean age of 41 ± 21 years. Seizure was controlled in 56% (20/36) of the DZP group and 50% (15/30) of the VPA group (P = 0.652). No patient in the VPA group developed respiratory depression, hypotension, or hepatic dysfunction, whereas in the DZP group, 5.5% required ventilation and 5.5% developed hypotension. Time (hour) for regaining consciousness after control was near-significantly longer in the DZP group [13(3.15-21.5)] than in the VPA group [3(0.75-11)] (P = 0.057). Virus encephalitis and long duration of GCSE were independent risk factors of drug resistance.

CONCLUSIONS

  Both IV VPA and continuous DZP infusion are effective second-line anticonvulsants for GCSE. IV VPA was well tolerated and free of respiratory depression and hypotension, which may develop in the DZP group. Outcome parameters were not significantly different between groups.

Differential effects of sodium salicylate on current-evoked firing of pyramidal neurons and fast-spiking interneurons in slices of rat auditory cortex

Sodium salicylate (SS) can penetrate the blood-brain barrier to target neurons in the central auditory system. Understanding how SS alters functional behaviors of different types of central auditory neurons will provide insights into the neural mechanisms of SS-induced tinnitus. Here, we report the differential effects of SS on current-evoked firing of pyramidal neurons and fast-spiking interneurons in layer II/III of auditory cortex slices in young rats (P12-P19). The two neuronal types were identified according to their characteristic patterns of current-evoked firing as recorded with whole-cell patch-clamp techniques and by their morphological features. Following perfusion of the brain slice with 1.4mM SS, the threshold current needed to evoke an action potential remained unchanged for pyramidal neurons (68.96+/-10.68 pA vs 70.39+/-12.14 pA, n=7, P>0.05), but significantly increased for fast-spiking interneurons (56.9+/-13.69 pA vs 74.04+/-15.73 pA, n=7, P<0.05). The drug perfusion caused no significant change in current-evoked firing rates in pyramidal neurons (-2.43+/-7.07%, n=14, P>0.05); however, it drastically and reversibly depressed those in fast-spiking interneurons by up to -49.88+/-10.39% (n=14, P<0.05). Our results suggest that functionally impairing fast-spiking interneurons, which are GABAergic and inhibitory, is probably one of the pathways through which SS raises excitability in the central auditory system and consequently produces tinnitus.

[Enhanced biodecolourization of azo dyes by the catalysis of anthraquinone dyes intermediators]

Enhanced biodecolourization of azo dyes by suspended and immobilized quinone-reducing community using kinds of anthraquinone dyes intermediators as redox mediators was investigated. The suspended bacterium community could enhance the biodecolourization of many kinds of azo dyes using bromoamine acid (BAA) as a redox mediator, the optimum conditions for Acid Red 3R were as follows: pH 6-9, glucose, BAA and initial dye concentrations 400-600 mg/L, 19-34.2 mg/L and < or = 900 mg/L, respectively. Under these conditions, the maximal decolourization rate was about 95%, which is reached within 7 h for suspended cells and 14 h for immobilized cells. However, the latter needed 38-57 mg/L BAA as a redox mediator. In addition, after 7 cycles without BAA addition, the decolourization rate of Acid Red 3R by immobilized cells retained over 85%.

Growth inhibition of cultured smooth muscle cells by corrosion products of 316 L stainless steel wire

The potential cytotoxicity on vascular smooth muscle cells of corrosion products from 316 L stainless steel, one of most popular biomaterials of intravascular stents, has not been highlighted. In this investigation, 316 L stainless steel wires were corroded in Dulbecco's modified eagle's medium with applied constant electrochemical breakdown voltage, and the supernatant and precipitates of corrosion products were prepared as culture media. The effects of different concentrations of corrosion products on the growth of rat aortic smooth muscle cells were conducted with the [3H]-thymidine uptake test and cell cycle sorter. Both the supernatant and precipitates of corrosion products were toxic to the primary culture of smooth muscle cells. The growth inhibition was correlated well with the increased nickel ions in the corrosion products when nickel concentration was above 11.7 ppm. The corrosion products also changed cell morphology and induced cell necrosis. The cell growth inhibition occurred at the G0/G1 to S transition phase. Similar to our recent study of nitinol stent wire, the present investigation also demonstrated the cytotoxicity of corrosion products of 316 L stainless steel stent wire on smooth muscle cells, which might affect the poststenting vascular response.

Human ERMAP: an erythroid adhesion/receptor transmembrane protein

A human cDNA and gene encoding for human ERMAP, a putative erythroid transmembrane adhesion/receptor protein, is reported. The predicted protein is made up of 475 amino acids and shares high homology with the murine ERMAP (73% identity and 14% conservative changes). Human Ermap is highly expressed in erythroid tissues and the protein localizes to the plasma membrane, particularly in sites of cell contact, and "cytoplasmic bodies." The extracellular segment contains one IgV fold that shares high homology with the butyrophilin family of milk proteins, autoantigens, and avian blood group antigens. In the intracellular region, there is a conserved B30.2 domain that is encoded by a single exon and is highly homologous with a similar domain in a diverse group of proteins, including butyrophilin, pyrin, and MID 1. The human Ermap gene is composed of 11 exons spanning 19 kb on chromosome 1p34.

The cytotoxicity of corrosion products of nitinol stent wire on cultured smooth muscle cells

Although nitinol is one of most popular materials of intravascular stents, there are still few confirmative biocompatibility data available, especially in vascular smooth muscle cells. In this report, the nitinol wires were corroded in Dulbecco's modified Eagle's medium with constant electrochemical breakdown voltage and the supernatant and precipitates of corrosion products were prepared as culture media. The dose and time effects of different concentrations of corrosion products on the growth and morphology of smooth muscle cells were evaluated with [(3)H]-thymidine uptake ratio and cell cycle sorter. Both the supernatant and precipitate of the corrosive products of nitinol wire were toxic to the primary cultured rat aortic smooth muscle cells. The growth inhibition was correlated well with the increased concentrations of the corrosion products. Although small stimulation was found with released nickel concentration of 0.95 +/- 0.23 ppm, the growth inhibition became significant when the nickel concentration was above 9 ppm. The corrosion products also altered cell morphology, induced cell necrosis, and decreased cell numbers. The cell replication was inhibited at the G0-G1 to S transition phase. This was the first study to demonstrate the cytotoxicity of corrosion products of current nitinol stent wire on smooth muscle cells, which might affect the postimplantation neointimal hyperplasia and the patency rate of cardiovascular stents.

Increased corrosion resistance of stent materials by converting current surface film of polycrystalline oxide into amorphous oxide

Current efforts of new stent technology have been aimed largely at the improvement of intravascular stent biocompatibility. Among the chemical characteristics of metallic stents, surface oxide corrosion properties are paramount. Using our unique technique, the currently marketed 316 L stainless steel and nitinol stent wires covered with polycrystalline oxide were chemically etched and then passivated to form amorphous oxide. Excellent metallic-stent corrosion resistance with an amorphous oxide surface was demonstrated in our previous in vitro study. For in vivo validation, we compared the corrosion behavior of different oxide surfaces on various forms of test wires in the abdominal aorta of mongrel dogs using open-circuit potential and cyclic anodic polarization measurements. After conduction, the retrieved test wires were observed under scanning electron microscope. No passivity breakdown was found for wires covered with amorphous oxide, while wires with polycrystalline oxide showed breakdown at potentials between +0.2 to + 0.6 V. It has been proven that severe pitting or crevice corrosion occurred on the surface of polycrystalline oxide, while the surface of amorphous oxide was free of degradations in our experiment. We have demonstrated that this amorphous oxide coating on metallic material provides better corrosion resistance, not only in vitro but also in vivo, and it is superior not only in strength safety but also in medical device biocompatibility.

Computerized rotational vestibular testing in normal subjects

BACKGROUND

As an integral part of the contemporary vestibular testing battery, computerized vestibular rotational testing provides physiologic stimuli and quantitative evaluation of the vestibulo-ocular reflex function of the horizontal semicircular canals. Clinically, it is most commonly used in the sinusoidal harmonic acceleration test (SHAT) and velocity step test. Because the results for a given subject may vary when tested using different facilities, the purpose of this study is to establish the normative data for our laboratory.

METHODS

Fifty-six normal subjects underwent the SHAT and velocity step test. Three parameters of SHAT--gain, phase and symmetry--were measured and recorded at 0.02, 0.05, 0.09 and 0.10 Hz. In the velocity step test, the three parameters of postrotatory nystagmus-time constant, maximum slow component eye velocity and directional preponderance were measured and recorded.

RESULTS

The means +/- standard deviations of gain in the SHAT were 0.47 +/- 0.16 at 0.02 Hz, 0.50 +/- 0.16 at 0.05 Hz, 0.50 +/- 0.16 at 0.09 Hz and 0.53 +/- 0.17 at 0.10 Hz. The coefficient of variation for SHAT gain was 0.32. The time constant means and standard deviations in the velocity step test were 13.44 +/- 3.53 and 13.52 +/- 3.69 for clockwise and counterclockwise rotations, respectively.

CONCLUSIONS

We conclude that computerized rotational vestibular testing is precise.

[Analytical study on processing of Scutellaria baicalensis Georyl by HPLC]

This paper deal with the effect of processing on Scutellaria baicalensis. A HPLC method for the determination of baicalin in the drug processed in four different ways has been established. The method is simple, specific and accurate. The recovery is 99.5% and relative standard deviation 0.99%.

Interaction between enkephalin and dopamine in the avian retina

Biochemical and pharmacological techniques were utilized to investigate the interaction between the enkephalinergic and dopaminergic systems in the chicken retina. Exogenously applied enkephalin and its analogues were observed to inhibit the release of preloaded dopamine from the retina. This inhibition was concentration-dependent and was suppressed by the opiate antagonist, naloxone. The relationship between enkephalinergic and dopaminergic amacrine cells was studied in retinas which were subjected to 6-hydroxydopamine (6-OHDA) treatments. 6-OHDA degenerated approximately 80-90% of those cells which exhibit high affinity uptake of [3H]dopamine. In 6-OHDA-treated retinas, the capacity of 3H-labelled [D-Ala2]methionine enkephalinamide to bind specifically to opiate receptors was substantially reduced (only 70-75% of the control). Scatchard analyses and ligand displacement studies indicated that this decrease in binding was due to a reduction in the number of opiate receptors. Taken together, these observations strongly indicate that a fraction of the opiate receptors in the chicken retina (25-30%) are closely associated with the population of dopaminergic amacrine cells.

Enkephalin in the goldfish retina

Enkephalin-like immunoreactive amacrine cells were visualized using the highly sensitive avidin-biotin method. The somas of these cells were situated in the inner nuclear and ganglion cell layers. Enkephalin-stained processes were observed in layers 1, 3, and 5 of the inner plexiform layer. The biosynthesis of sulfur-containing compounds in the goldfish retina was studied by means of a pulse-chase incubation with 35S-methionine. A 35S-labeled compound, which comigrated with authentic Met5-enkephalin on high-performance liquid chromatography (HPLC), was synthesized and was bound competitively by antibodies to enkephalin and by opiate receptors. This compound was tentatively identified as "Met5-enkephalin." The newly synthesized 35S-Met5-enkephalin was released upon depolarization of the retina with a high K+ concentration. This K+-stimulated release was greatly suppressed by 5 mM Co2+, suggesting that the release was Ca2+ dependent. Using a double-label technique, enkephalin immunoreactivity and gamma-aminobutyric acid (GABA) uptake were colocalized to some amacrine cells, whereas others labeled only for enkephalin or GABA. The possible significance of enkephalin-GABA interactions is also discussed.

The self-regulating synapse: a functional role for the co-existence of neuroactive substances

Although the co-localizations of neuroactive substances, such as transmitters and peptides, in identified neurons is now a common histochemical phenomenon, the physiological roles and functional significance of such co-existence are largely unknown. Using the vertebrate retina as a model for the central nervous system, we have examined the relationship between co-existence and co-function. We propose here that the co-localization of neuroactive substances in a synaptic terminal provides the structural configuration to ensure the co-release of two or more predetermined substances into the same synaptic cleft, resulting in the capability of the presynaptic neuron to stringently regulate its own activities and output.

A monoclonal antibody specific for retinal ganglion cells of mammals

The development of specific markers for retinal ganglion cells is an area of great interest in retinal research. In this study we report on a monoclonal antibody (AB5) which specifically labels ganglion cells in rabbit, cat and monkey, as well as a variety of other mammalian species. Labelling of ganglion cells was also observed in isolated cell preparations of rabbit retina.

Opioid pathways in an avian retina. I. The content, biosynthesis, and release of Met5-enkephalin

By means of an enzyme-linked immunosorbent assay, the concentration of enkephalin-immunoreactive substances was estimated to be about 25 nM in the chicken retina. The biosynthesis of 3H-Met5-enkephalin in this retina was studied by a pulse-chase incubation technique. Isolated retinas were incubated with 0.2 ml of oxygenated Ringer's solution containing 40 microCi of [3H]methionine and trasylol, a peptidase inhibitor, for 30 min at room temperature. The tissue was then rinsed three times in large volumes of Ringer's solution and incubated in the same solution containing unlabeled methionine (100 micrograms/ml) and trasylol for at least another hour. The products synthesized were extracted in acetic acid and assayed by high performance liquid chromatography (HPLC) and immunoassay. A peak of radioactivity that comigrated with Met5-enkephalin on HPLC and cross-reacted with antibodies against enkephalins was detected. The level of 3H-Met5-enkephalin radioactivity increased approximately 10-fold as the chase-incubation period increased from 0 to 120 min, suggesting that, as in other tissues, Met5-enkephalin may be synthesized as part of a larger precursor. The newly synthesized Met5-enkephalin could be released by depolarization of the retina with high extracellular K+ concentration. Furthermore, this K+-stimulated release was greatly suppressed by 5 mM Co2+ in the medium, suggesting that this release is Ca2+-dependent and may be synaptically mediated.

Opioid pathways in an avian retina. II. Synaptic organization of enkephalin-immunoreactive amacrine cells

Peroxidase-antiperoxidase immunocytochemistry was utilized to investigate the synaptic organization of enkephalin-like immunoreactive amacrine (Enk-amacrine) cells in the chicken retina. An initial light microscopic analysis revealed that immunostained cell bodies were situated in either the second or third tier of cells from the border of the inner nuclear and inner plexiform layers. The processes of such cells extended into the inner plexiform layer where they ramified as a fine plexus in sublaminae 1 and 3 to 5. At the ultrastructural level, enkephalin-positive somas exhibited a rather dense and evenly distributed peroxidase reaction product throughout their cytoplasm. Furthermore, the nucleus of Enk-amacrine cells was characterized by a round, unindented nuclear membrane. Immunoreactive processes of such cells were found to receive synaptic input from unstained amacrine and bipolar cells. Immunolabeled varicosities formed conventional synaptic contacts onto other vesicle-filled, nonimmunoreactive profiles tentatively suggested to originate from amacrine cells. Bipolar cell terminals did not receive synaptic input from stained varicosities of enkephalin-immunoreactive amacrine cells. Moreover, each of the above synaptic relationships were identified in each of sublaminae 1, and 3 to 5 of the inner plexiform layer. In addition, labeled varicosities of Enk-amacrine cells synapsed upon unstained processes which lacked synaptic vesicles and possibly arise from ganglion cells. Enkephalin-positive processes were also observed to synapse upon the vitreal pole of unstained somas situated in the innermost cell row of the inner nuclear layer. Lastly, large immunoreactive varicosities of Enk-amacrine cells were often characterized by the presence of large dense-core vesicles in addition to typical, small agranular synaptic vesicles.

The signature hypothesis: co-localizations of neuroactive substances as anatomical probes for circuitry analyses

The recent discoveries that a neuron in the vertebrate retina may contain more than one neuroactive substance (transmitter or neuropeptide) raise the possibility that within each class of neurons, every morphologically and physiologically distinct cell type may be uniquely identified and categorized by the neuroactive substances that it contains. This article examines the evidence to-date for such a conjecture and discusses some of its potential applications and implications.

Interactions between enkephalin and GABA in avian retina

In addition to conventional neurotransmitters such as acetylcholine, dopamine, glycine and gamma-aminobutyric acid (GABA), a number of peptide-immunoreactive substances have recently been localized in the vertebrate retina. The functional roles of these retinal peptides and their interactions with conventional neurotransmitters are largely unknown. We have previously shown that exogenous opiates affect both the release of GABA and the firing patterns of ganglion cells in the goldfish retina, and we have now begun a systematic characterization of the opioid pathways in the chicken retina, because, among vertebrate retinas, avian retinas contain the highest concentration of enkephalins. Monoclonal antibodies specific for enkephalin have been used to demonstrate that a subpopulation of enkephalin-containing amacrine cells exists in the chicken retina. This retina also synthesizes Met-enkephalin and releases it on cell depolarization. The enkephalin-induced inhibition of GABA release in goldfish retina led us to examine whether similar interactions occur in chicken, and if so, whether enkephalins and GABA coexist in the same amacrine cells. Our results, presented here, indicate that exogenous enkephalins do indeed inhibit GABA release in the chicken retina. Surprisingly, we found that although some amacrine cells contain both enkephalin and GABA, others contain only one or the other.