[Transoral robotic thyroidectomy via vestibular approach: a retrospective study of 107 cases in a single center]

Objective: To investigate the short-term outcome of transoral robotic thyroidectomy. Methods: This is a retrospective case series study. The clinicopathologic characteristics and postoperative results of 107 patients who underwent transoral robotic thyroidectomies in the Department of Thyroid and Breast Surgery of the 960th Hospital of People's Liberation Army from May 2020 to August 2023 were retrospectively analyzed. There were 12 males and 95 females, with an age of (31.8±9.4) years (range: 11 to 55 years), including 20 benign tumors and 87 thyroid papillary carcinoma. Postoperative follow-up was carried out through returning visit and telephone, mainly to observe the recovery of postoperative complications, cosmetic effects and recurrence results. Results: All transoral robotic thyroidectomy was successfully completed without conversion to open surgery. The tumor size of thyroid papillary carcinoma patients was (5.6±2.7) mm (range: 2 to 15 mm). Furthermore, central cervical lymph node metastasis was found in 45 cases. The number of central cervical lymph nodes retrieved and metastasized (M(IQR)) were 11 (8) (range: 3 to 26) and 1 (3) (range: 0 to 13), respectively. There was no recurrent laryngeal nerve injury and permanent hypoparathyroidism. The transient hypoparathyroidism after surgery was 8 cases. Other complications occurred as follows: postoperative infection (n=1), left submandibular perforation (n=1), skin scald (n=1), and perioral numbness (n=1), oral tear (n=2). The postoperative stay was 6 (2) days (range: 3 to 11 days). No local lymph node recurrence or metastasis occurred after a follow-up of (22.6±10.0) months (range: 1.0 to 37.4 months). All patients were satisfied with the postoperative cosmetic results, the aesthetic effect score was 9.3 (0.2) (range: 8.4 to 9.6) one month after surgery. Conclusion: For highly screened patients with early thyroid cancer, experienced surgeons can perform a transoral robotic thyroidectomy that has excellent cosmetic results.

The Effect of Left-Behind Experience and Self-Esteem on Aggressive Behavior in Young Adults in China : A Cross-Sectional Study

There is little investigation on the independent effects of left-behind experience (LBE) on self-esteem and aggressive behavior in Chinese young adult populations, or the interaction effects of LBE and self-esteem on aggressive behavior. Thus, a school-based health survey was conducted in Anhui province in China in 2017. A total of 4,154 college students completed standard questionnaires which contain details of left-behind-related characters, self-esteem, aggressive behavior, and sociodemographic profile. Of included students, 55.3% were those with LBE (LBEs). Compared to students without left-behind experiences (NLBEs), LBEs had significantly increased scores of aggressive behavior and decreased score of self-esteem. The increased aggression in LBEs was highly related to longer left-behind duration, younger age of left-behind for the first time, and decreased self-esteem. On the other side, the aggressive behavior was demonstrated negatively correlated with self-esteem in both LBEs and NLBEs. There was an interaction effect of left-behind duration and self-esteem on physical aggression and of frequency of contacting with parents and self-esteem on verbal aggression. Besides, the interaction of primary caregiver and self-esteem on hostility and aggression toward self were also observed, respectively. Our results indicated LBEs and low self-esteem are associated with increased risk of aggressive behavior in Chinese young adults. The increased aggressive behavior in LBEs were highly related to longer left-behind duration, younger age of left-behind for the first time and decreased self-esteem. In those LBEs with some certain left-behind-related characters, aggressive behavior decreased more prominently with the increase of self-esteem. Strategies to improve self-esteem, particularly among young adults who have certain characters of LBE, should be a significant component of prevention and interventions of aggressive behavior.

[Complications of Da Vinci robot thyroid surgery by bilateral axillo-breast approach]

Objective: To evaluate the complications of Da Vinci robotic thyroid surgery by bilateral axillo-breast approach. Methods: A retrospective analysis of complications was conducted on 1, 198 cases of Da Vinci robotic thyroid surgery by bilateral axillo-breast approach of the 960 th Hospital of the People's Liberation Army from February 2014 to March 2020. There were 263 men and 935 women, age ranged from 9 to 68 years old, and included 288 benign lesions and 910 malignancies according to preoperative imaging examination, FNAC, and intraoperative frozen pathology. Results: Surgical complications occurred in 187 (15.61%) patients, including 10 cases of temporary larynx nerve injury (0.83%), 1 case of permanent larynx nerve injury (0.08%), and 152 cases of temporary hypoparathyroidism (12.69%), no permanent hypoparathyroidism, 1 case of hypoglossal injury (0.08%), 2 cases of facial nerve jaw branch damage (0.17%), 2 cases of trachea injury (0.17%), no esophagus damage, 5 cases of celiac leakage (0.42%), 3 cases of neck skin adhesion (0.25%), 2 cases of subdermal bleeding (0.17%), 2 cases of skin burns (0.17%), 5 cases of hematoma (0.42%), 1 case of cephalic artery rupture (0.08%), 1 case of jugular vein rupture (0.08%), no tumor cultivation, no arm plex nerve, accessory nerve or phrenic nerve damage. Conclusion: Da Vinci robot thyroid surgery by bilateral axillo-breast approach is safe, with less severe complications.

[Mechanism of lncRNA-SRLR induced invasion and metastasis in U2OS osteosarcoma cells]

Objective: To explore the potential mechanism of sorafenib resistance associated long non-coding RNA (lncRNA-SRLR) promoted invasion and metastasis in U2OS osteosarcoma cells. Methods: We transfected U2OS cells with negative control lentivirus (LV-NC) or lncRNA-SRLR overexpressed lentivirus (LV-over/SRLR) particles. LV-NC and LV-over/SRLR stable transfected cells (U20S/NC and U20S/SRLR) were selected by primary cell culture medium containing puromycin. The mRNA expressions of lncRNA-SRLR and procollagen-lysine, procollagen-lysine 2-oxoglutarate 5-dioxygenase 2 (PLOD2) were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The effect of lncRNA-SRLR on the invasion of U2OS cells were determined by wound-healing assay and Transwell migration assay. The effect of SRLR on the interleukin-6 (IL-6) secretion of U2OS cells was evaluated by enzyme-linked immunosorbent assay (ELISA) analysis. The subcellular distribution of SRLR in U2OS cells was detected by fluorescence in situ hybridization (FISH) analysis.The expression of PLOD2 in cells was detected by immunofluorescence (IF). The expressions of PLOD2 and focal adhesion kinase (FAK)/signal transducer and activator of transcription 3 (STAT3) signal pathway related proteins in U2OS/NC and U2OS/SRLR cells were detected by western blotting. Results: qRT-PCR assay showed that mRNA expressions of lncRNA-SRLR and PLOD2 in U2OS/SRLR cells were (3 964.97±0.05) and (2.77±0.11), respectively, significantly higher than those in U2OS/NC cells (P<0.001 or P<0.01). The results of wound-healing and Transwell migration assay showed that over-expression of SRLR markedly promoted the invasion ability of U2OS cells (P<0.05). The result of ELISA analysis showed that the IL-6 secretions in U2OS/NC or U2OS/SRLR cells were (125.38±11.22) pg/ml or (119.97±13.43) pg/ml, without statistical significance (P>0.05). The subcellular distribution assay revealed that lncRNA-SRLR is predominately located in the nucleus. The result of IF showed that compared with U2OS/NC cells, the expression of PLOD2 was up-regulated in U2OS/SRLR cells. The result of western blotting showed that over-expression of SRLR significantly increased the expression levels of PLOD2, phosphorylation (p)-FAK and p-STAT3 in U2OS cells (P<0.01). Conclusion: lncRNA-SRLR promotes invasion and metastasis of osteosarcoma by activating PLOD2-FAK/STAT3 signal axis.

The impacts of maternal separation experience and its pattern on depression and dysfunctional attitude in middle school students in rural China

BACKGROUND

In China, because of the growth of economically driven rural-to-urban migration, there are lots of children in rural area who are separating or have separation experience with their parents. Until now, few studies focused on solely maternal separation and no research studied whether its pattern will affect children's later psychological status.

AIM

The aim of this study was to determine whether early or late maternal separation affects depression and dysfunctional attitude in middle school students and what is the role of cumulative duration and meeting frequency.

METHODS

Maternal separation experience was obtained by using questionnaires. We got early maternal separation group first. Then, late maternal separation and control group were obtained with the same number by matching grade, sex and family socioeconomic status. All the students in the three groups completed the scales of Children's Depression Inventory (CDI) and Dysfunctional Attitude Scale (DAS).

RESULTS

Both CDI and DAS scores of early separation group are higher than the other two groups. When we split the data by sex, only females presented the same results. When cumulative duration is short, there is significant difference in both scores of CDI and DAS among the three groups, which showed the scores of early separation group are higher than the other two groups. When the cumulative duration is long, there is no significant difference among the three groups. When meeting frequency is high, there is no significant difference among the three groups. When it is low, there is significant difference among the three groups, which showed the CDI and DAS scores of early separation group are higher than the other two groups. Furthermore, the same results are also found in females.

CONCLUSION

Early maternal separation may exert negative influence on student's depression and dysfunctional attitude. The sex, cumulative duration and meeting frequency may also play important roles in the effect.

[Experimental study on the improvement of Ilizarov transverse tibial bone transport and microcirculation reconstruction technique]

Objective: To observe the effect of traditional and modified Ilizarov transverse tibial bone transport on microvascular regeneration of lower limbs in dogs. Methods: After general anesthesia on 10 experimental dogs, traditional and modified transverse tibial bone transport were performed on both tibias respectively. The control group was treated with the traditional method (the periosteum and bone flap were completely isolated), while the experimental group was treated with the modified method (the fibular periosteum of the open window bone flap was retained). All the external fixators were pulled outwards at a speed of 1 mm every day from 5 days after operation;after one week, the external fixators were moved back every 3 days for one week. The situation of wounds and activity of lower limbs were observed. Simultaneously, the angiogenesis was observed by digital subtraction angiography (DSA) through femoral artery at different stages, and the density of vascular endothelial cells measured by local tissue sections. The data before and after the operation were compared with paired t test. Results: The operation was successfully completed in 10 experimental dogs, and all wounds healed about 1 week after the operation. There was no significant abnormality in lower limb movements in all dogs. Peripheral blood vessel area in middle leg of lower limb in 4 weeks and 8 weeks after operation was (5.9±0.4) mm(2) and (6.9±0.6) mm(2) in control group and it was (6.2±0.6) mm(2) and (8.0±0.6) mm(2) in experimental group, respectively; all were significantly improved than those before the operation ((5.0±0.4) mm(2), (4.9±0.4) mm(2), respectively) (F=446.457, 829.192, both P<0.05). There was no significant differences in vessel area between the two groups at the 4th week after operation (t=1.216, P=0.240), but there was significant difference at the 8th week after operation between the two groups (t=4.423, P=0.000). The percentage of vascular endothelial cells in stained cells under endoscopy was 4.42%±0.28% and 5.63%±0.53% in the control group at the 8th week; and in the experimental group, it was 5.35%±0.26% and 7.18%±0.25%, respectively;all were significantly elevated than those before the operation; and there were significant differences between the two groups (t=7.35, 8.30, both P<0.05). Conclusion: Transverse tibial bone transport and microvascular network regeneration technology can reconstruct the microvasculature below the calf of dogs; the method of window-opening osteotomy is improved to "door" type window-opening, it can retain the lateral periosteum of tibial crest and regenerate the microvasculature network more abundantly.

[Effects of menopausal factor on fine anatomy of bladder urethra and vagina in women undergoing vaginal delivery]

Objective: To explore the effects of menopausal factor on fine anatomy of bladder, urethra and vagina in women undergoing vaginal delivery. Methods: Gynecological patients in Nanfang hospital from January 2013 to October 2016 were collected, and then the patients whose MRI images quality meet the require of reconstruction, with the history of vaginal delivery experience, without any cesarean section experience, and the first labor time was ≤30 years old were enrolled. The patients who had pelvic floor dysfunction when done MRI examinations were excluded. Finally, 238 cases were randomly selected out, and 238 models of data were reconstructed and measured by Mimics and UG software. The independent t test was used to do the comparison between menopausal group and those not yet menopause. Results: First, we built 238 3D models totally. Second, the parameters related with bladder and urethra: the angle of bladder and urethra, β angle, urethra pubic angle, α angle, retropubic space, the length between bladder neck and edge of pubic midpoint, and urethral striated muscle thickness of menopausal group were bigger than those of pre-menopausal group. While for the urethra tilt angle, the former group was smaller than that of the latter group. But there was no significant statistical differences between two groups. Third, the parameters related with vagina: the proximal urethral vaginal gap of the post-menopause group was smaller than that of pre-menopausal group, while for the middle and distal urethral vaginal gap, the former group was bigger than that of the latter group. The length and width of vaginal anterior wall of the post-menopausal group were smaller than those of pre-menopausal group. Beside the middle urethral vaginal gap, all the difference between two groups had no statistical meaning. The 2D shape of axial vaginal, H type occupation of the former group was obviously lower than that of the latter group. Conclusions: Menopause has an effect on fine anatomy of pelvic organ. Especially on the shape of vagina, the middle urethral vaginal gap become much wider after menopause, the occupation of shallow concave type become much higher post-menopausal. It means the lateral and backward support function of the urethra and vagina is relatively weakened after menopausal, and the shape of vagina become smaller.

Inverse incoherent engineering

We propose a protocol to construct shortcuts of adiabaticity for open quantum systems in unitary evolution. Using the dynamical invariants of open quantum systems, we design a convenient form of the driver Hamiltonian to accelerate the adiabatic decoherence free subspaces scheme (TDFs) and engineer a quantum state from the initial state into the target state. Since the trajectory of TDFSs is determined by the incoherent control process, we would like to call it as the inverse incoherent engineering protocol. We apply the method to a two-qubits system which interacts with a time-dependent vacuum squeezed field to prepare some maximally entangled states of it. The results illustrate that our protocol can be used both in the adiabatic and nonadiabatic regime with perfect fidelity.

[Investigation of influencing factors associated with neck-shoulder symptoms among middle school students in three cities in China]

Objective: The aim of this study was to describe the distribution of neck-shoulder symptoms among middle school students, and to explore its influence factors. Methods: A cross-sectional survey was conducted on 24 middle schools in Shenyang, Zhengzhou and Shenzhen by purposive sampling method. In each middle school, 3 to 4 classes were selected from each grade all the students in the selected class would be recruited to the survey to investigate the demographic characteristics, neck-shoulder symptoms, physical exercise time, academic stress, screen behavior, sedentary behavior and other information by questionnaire. A total of 10 566 questionnaires were issued and 10 270 valid questionnaires were withdrawn. The prevalence of neck-shoulder symptoms among students were compared by different characteristics. Logistic regression models were applied to examine influencing factors associated with neck-shoulder symptoms. Results: The prevalence of neck-shoulder symptoms among middle school students was 19.2% (1 968/10 270), while it was 22.6% (1 137/5 039) among girls and 15.9% (831/5 231) among boys; the difference showed statistical significance (P<0.001). The prevalence of neck-shoulder symptoms was separately 13.3% (253/1 901) in seventh grade, 16.8% (326/1 942) in eighth grade, 18.5% (299/1 617) in ninth grade, 21.8% (417/1 915) in sophomore, 21.4% (345/1 611) in junior, 25.5% (328/1 284) in senior; the difference showed statistical significance (P<0.001). The multivariate logistic regression analysis showed that in the last 3 months, students who always playing mobile phone ≥40 min continuously (OR=4.66, 95%CI: 3.95-5.49), watching TV ≥40 min continuously (OR=4.01, 95%CI: 3.39-4.73), using computer ≥40 min continuously (OR=3.61, 95%CI: 3.09-4.23), doing homework ≥60 min continuously (OR=3.25, 95%CI: 2.79-3.79), the average daily sitting time ≥10 h (OR=4.95, 95%CI: 4.25-5.77), and always sitting ≥90 min continuously (OR=5.18, 95%CI: 4.42-6.06) were risk factors of neck-shoulder symptoms. Conclusion: The prevalence of neck-shoulder symptoms was high among middle school students in China, especially girls in senior grades. Long time, high frequency video behaviors and sedentary behaviors were related to the occurrence of neck-shoulder symptoms among middle school students.

[Mechanism of long non-coding RNA-metastasis associated lung adenocarcinoma transcript 1 induced invasion and metastasis of esophageal cancer cell EC-109]

Objective: To investigate the effect and mechanism of long non-coding RNA-metastasis associated lung adenocarcinoma transcript 1, (LncRNA-MALAT1) on invasion and metastasis of esophageal cancer cell EC-109. Methods: EC-109 cells were transfected with lentiviral vector carrying short hairpin RNA of MALAT1( shRNA-MALAT1) or a nonspecific shRNA control (shRNA-control). The expressions of MALAT1, microRNA-200a, ZEB1 and ZEB2 were detected by qRT-PCR. The effect of shRNA-MALAT1 on invasion of EC-109 cells was determined by transwell assay. The expressions of components of epithelial-msenchymal transition pathway in EC-109 cells were determined by immunofluorescence array and western blotting. The expression relationship between MALAT1 and miR-200a in EC-109 cells was detected by dual-luciferase reporter assay. Results: The result of qRT-PCR showed that the expressions levels of MALAT1, ZEB1 and ZEB2 in shRNA-MALAT1 group were 0.43±0.06, 0.64±0.04 and 0.51±0.04, respectively, significantly lower than 0.97±0.08, 1.06±0.07 and 0.98±0.05 in shRNA-control group and 1 in control group, respectively(all P<0.05). Transwell assay showed that the number of invaded cells in shRNA MALAT1 group was (96.81±10.43) per low-power field, markedly lower than that of (278.44±13.28) per low-power field in shRNA-control group (P<0.01). Immunofluorescence staining and Western blotting showed that MALAT1 downregulation significantly reduced the expressions of proteins related to EMT signal pathway in EC-109 cells.Dual luciferase reporter assay showed that compared to negative control, the activities of luciferase reporter in EC-109 cells co-transfected with pmirGLO-MALAT1-wt and miR-200a were significantly down-regulated. While co-transfected pmirGLO-MALAT1-mut with miR-200a mimics had no effect on the luciferase reporter activities of MALAT1. Conclusion: LncRNA MALAT1 functions as a competing endogenous RNA to regulate the expressions of ZEB1 and ZEB2 by sponging miR-200a and promotes invasion and migration of esophageal cancer cells through inducing epithelial-mesenchymal transition.

Construction of a protein-protein interaction network of Wilms' tumor and pathway prediction of molecular complexes

Wilms' tumor (WT), or nephroblastoma, is the most common malignant renal cancer that affects the pediatric population. Great progress has been achieved in the treatment of WT, but it cannot be cured at present. Nonetheless, a protein-protein interaction network of WT should provide some new ideas and methods. The purpose of this study was to analyze the protein-protein interaction network of WT. We screened the confirmed disease-related genes using the Online Mendelian Inheritance in Man database, created a protein-protein interaction network based on biological function in the Cytoscape software, and detected molecular complexes and relevant pathways that may be included in the network. The results showed that the protein-protein interaction network of WT contains 654 nodes, 1544 edges, and 5 molecular complexes. Among them, complex 1 is predicted to be related to the Jak-STAT signaling pathway, regulation of hematopoiesis by cytokines, cytokine-cytokine receptor interaction, cytokine and inflammatory responses, and hematopoietic cell lineage pathways. Molecular complex 4 shows a correlation of WT with colorectal cancer and the ErbB signaling pathway. The proposed method can provide the bioinformatic foundation for further elucidation of the mechanisms of WT development.

Analysis of the gene-protein interaction network in glioma

Glioma is the most aggressive type of brain tumor. Great progress has been achieved in glioma treatment, but the protein-protein interaction networks underlining glioma are poorly understood. We identified the protein-protein interaction network for glioma based on gene expression and predicted biological pathways underlying the molecular complexes in the network. Genes involved in glioma were selected from the Online Mendelian Inheritance in Man (OMIM) database. A literature search was performed using the Agilent Literature Search plugin, and Cytoscape was used to establish a protein-protein interaction network. The molecular complexes in the network were detected using the Clusterviz plugin, and pathway enrichment of molecular complexes was performed using DAVID online. There were 378 glioma genes in the OMIM database. The protein-protein interaction network in glioma contained 1814 nodes, 6471 edges, and 8 molecular complexes. There were 17 pathways (false discovery rate <1), which were related to cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, chemokine signaling pathway, oocyte meiosis, progesterone-mediated oocyte maturation, transmembrane transport of small molecules, metabolism of amino acids, and notch signaling pathway, among others. Our results provide a bioinformatic foundation for further studies of the mechanisms of glioma.

Species identification and evolutionary inference of the genera Megalobrama and Parabramis (Cyprinidae: Cultrinae) in China

The species boundaries and evolutionary relationships of two closely related genera, Megalobrama and Parabramis, were inferred from the partial mitochondrial cytochrome oxidase subunit I (COI) gene, NADH dehydrogenase subunit 2 (ND2) gene and their concatenated segment. Phylogenetic reconstructions showed that among the three breams, Megalobrama amblycephala and Megalobrama skolkovii are more closely related to each other than either is to Megalobrama terminalis. The taxonomy of M. pellegrini should be reconsidered. The divergence time estimation based on the assumption of a global molecular clock indicated that speciation and dispersal of the two genera might have occurred at approximately Pliocene to Late Pleistocene, due to major paleo-environmental events associated with monsoon evolution and the formation of the Three Gorges of the Yangtze River.

Protective effects of omega-3 fish oil on lead-induced impairment of long-term potentiation in rat dentate gyrus in vivo

In order to evaluate the effect of omega-3 fish oil supplement by gavage (0.4 mL/100 g body weight) on the chronic lead-induced (0.2% lead acetate) impairments of long-term potentiation (LTP) in rat dentate gyrus (DG) in vivo, we designed the experiments which were carried out in four groups of newborn Wistar rats (the control, the lead-exposed, the control with fish oil treatment and the lead-exposed with fish oil treatment, respectively). The excitatory postsynaptic potential (EPSP) and population spike (PS) amplitude were measured in the DG of rats with above different treatments at the age of 80-90 d in response to stimulation applied to the lateral perforant path. The results showed (1) postnatal chronic lead-exposure impaired LTP measured on both EPSP slope and PS amplitude in DG area of the hippocampus; (2) in the control rats, omega-3 fish oil had no effect on LTP while in the lead-exposed rats, omega-3 fish oil had a protective effect on LTP. These results suggest that omega-3 fish oil supplement could protect rats from the lead-induced impairment of LTP. Omega-3 fish oil might be a preventive substance in reducing LTP deficits induced by lead.

Inhibitory effect of melatonin on lung oxidative stress induced by respiratory syncytial virus infection in mice

Previous research has shown that antioxidant (butylated hydroxyanisole) treatment ameliorates respiratory syncytial virus (RSV)-induced disease and lung inflammation. Melatonin has been reported to exhibit a wide varieties of biological effects, including antioxidant and anti-inflammation, and has no evident toxicity and side effect. But it is not known whether melatonin would modify RSV-induced lung disease and oxidative stress. The present study was to establish the involvement of oxidative stress in the pathogenesis of RSV-induced lung inflammation, and to investigate the protective effect of administration of melatonin in mice with RSV-induced oxidative pulmonary injury for 4 days. Malondialdehyde (MDA), an end product of lipid peroxidation, and glutathione (GSH) and superoxide dismutase (SOD) and nitric oxide (NO) levels were evaluated in lung tissue homogenates by spectrophotometry. Hydroxyl radical (.-OH), one of the indicators of free radical formation, was also detected in lung homogenates by Fenton reaction. Tumor necrosis factor-a (TNF-a) concentrations in mouse serum were measured with ELISA assay. The results demonstrated that the mice intranasally inoculated with RSV resulted in oxidative stress changes by increasing NO, MDA and .-OH levels, and decreasing GSH and SOD activities, whereas administration of melatonin significantly reversed all these effects. Furthermore, melatonin inhibited production of proinflammatory cytokines such as TNF-a in serum of RSV-infected mice. These results suggest that melatonin ameliorates RSV-induced lung inflammatory injury in mice via inhibition of oxidative stress and proinflammatory cytokine production and may be as a novel therapeutic agent in virus-induced pulmonary infection.

Histology and mucin histochemistry of the digestive tract of yellow catfish, Pelteobagrus fulvidraco

The histology and characteristics of mucins secreted by epithelial mucous cells of the digestive tract in yellow catfish, Pelteobagrus fulvidraco were investigated using light microscope and transmission electron microscope. The digestive tract was divided into a pharynx, oesophagus, U-shaped stomach (with a cardiac, fundic and pyloric part) and intestine, composed of anterior intestine, middle intestine and posterior intestine, which consisted of a mucosa (epithelial layer), lamina propria-submucosa, muscularis and serosa. A large number of isolated longitudinal striated muscular bundles were present in the lamina propria-submucosa of pharynx. Goblet cells were observed throughout the digestive tract, except in the stomach. In the cardiac and fundic stomach, a plenty of gastric glands were observed, whereas they were absent in the pyloric part. Numerous mitochondria and endoplasmic reticulum were observed in the columnar epithelial cells of the intestine, especially of the anterior part. The epithelial mucous cells contained neutral or other two mixtures of acid and neutral mucins, the first being the most common. The neutral mucin was the only type of mucins in the stomach, anterior intestine and middle intestine. The results of this study will be helpful for understanding the digestive physiology and diagnosing some gastrointestinal diseases in yellow catfish.

Effects of chronic administration of melatonin on spatial learning ability and long-term potentiation in lead-exposed and control rats

OBJECTIVE

To explore the changes in spatial learning performance and long-term potentiation (LTP) which is recognized as a component of the cellular basis of learning and memory in normal and lead-exposed rats after administration of melatonin (MT) for two months.

METHODS

Experiment was performed in adult male Wistar rats (12 controls, 12 exposed to melatonin treatment, 10 exposed to lead and 10 exposed to lead and melatonin treatment). The lead-exposed rats received 0.2% lead acetate solution from their birth day while the control rats drank tap water. Melatonin (3 mg/kg) or vehicle was administered to the control and lead-exposed rats from the time of their weaning by gastric gavage each day for 60 days, depending on their groups. At the age of 81-90 days, all the animals were subjected to Morris water maze test and then used for extracellular recording of LTP in the dentate gyrus (DG) area of the hippocampus in vivo.

RESULTS

Low dose of melatonin given from weaning for two months impaired LTP in the DG area of hippocampus and induced learning and memory deficit in the control rats. When melatonin was administered over a prolonged period to the lead-exposed rats, it exacerbated LTP impairment, learning and memory deficit induced by lead.

CONCLUSION

Melatonin is not suitable for normal and lead-exposed children.

Acetate-dependent methylation of two corrinoid proteins in extracts of Methanosarcina barkeri

Corrinoid proteins have been implicated as methyl carriers in methane formation from acetate, yet specific corrinoid proteins methylated by acetate-derived intermediates have not been identified. In the presence of ATP, H2, and bromoethanesulfonic acid, label from 3H- or 2-14C-labeled acetate was incorporated into the protein fraction of cell extracts of Methanosarcina barkeri. Incorporated label was susceptible to photolysis, yielding labeled methane as the anaerobic photolysis product. Size exclusion high-pressure liquid chromatography (HPLC) demonstrated the presence of at least three labeled proteins with native molecular sizes of 480, 200, and 29 kDa, while electrophoresis indicated that four major labeled proteins were present. Dual-label experiments demonstrated that these four proteins were methylated rather than acetylated. Two of the proteins (480 and 29 kDa) contained the majority of radiolabel and were stably methylated. After labeling with [2-14C]acetate, the stable 14CH3-proteins were partially purified, and 14CH3-cofactors were isolated from each protein. UV-visible spectroscopy and HPLC demonstrated these to be methylated corrinoids. When the 480-kDa corrinoid protein was purified to 70% homogeneity, the preparation was found to have subunits of 40 and 30 kDa. The 480-kDa protein but not the 29-kDa protein was methylated during in vitro methanogenesis from acetate and demethylated as methanogenesis ceased, consistent with the involvement of this protein in methane formation.