[Randomized controlled study on the application effect of a new type of intravenous radiofrequency closed therapy system made in China and an imported system]

Objective: To compare the application effect of domestic and imported intravenous radiofrequency closure system in the treatment of primary varicose veins of lower extremities. Methods: This single-center prospective, non-inferiority randomized controlled trial was performed in the Department of Vascular Surgery, the Fourth Affiliated Hospital, Zhejiang University School of Medicine from January 2021 to January 2022. Patients with primary varicose veins of lower extremities who met the ataxation criteria were randomly assigned to the experimental group(domestic novel venous radiofrequency closure system) or the control group(imported venous radiofrequency closure system) in a ratio of 1∶1. The two groups of subjects were compared in terms of target vein closure rate, technical success rate, system operation performance, incidence of adverse events and incidence of serious adverse events(SAE) within 6 months after surgery. Quantitative data were compared by Mann-Whitney U test, and categorical data were compared by χ2 test and non-inferiority test. Results: A total of 80 subjects were included in the trial (41 in the experimental group and 39 in the control group), including 27 males and 53 females, aged (M(IQR)) 55(23) years (range:40 to 78 years). There were 48 cases of left lower limb and 32 cases of right lower limb. The technical success rate and system control performance between the groups were 100%.The incidence of adverse events (58.5% (24/41) vs. 61.5% (24/39), χ2=0.075, P=0.784), and the incidence of SAE (7.3% (3/41) vs. 5.1% (2/39), χ2=0.163, P=0.686) within 6 months after surgery in experimental group and control group had no statistical significance. There was one device-related adverse event in each of the two groups. In the experimental group, one patient developed endovenous heat-induced thrombosis after surgery and recovered after taking rivaroxaban tablets. One patient in the control group had pain in the upper right thigh for more than 1 day after operation, which was cured after using analgesic cream. No device-related SAE occurred. The venous closure rate of the experimental group was 100% (38/38) at 6 months after surgery, and that of the control group was 97.4% (37/38). The difference between the two groups was 2.63% (95%CI:-3.19 to 8.45, Z=4.865, P<0.01), and the 95%CI lower limit of the difference in target venous closure rate between two groups was greater than the non-inferiority threshold of -10.00%. Conclusion: The early application effect of the new domestic intravenous radiofrequency closure system in patients with primary varicose veins of lower extremities is in line with expectations, it is not inferior to the imported system.

[Interpretation of Chinese expert consensus on the surgical treatment for adenocarcinoma of esophagogastric junction(2024 edition)]

Due to the unique nature of its anatomical location, the adenocarcinoma of esophagogastric junction (AEG) has been a subject of controversy and disagreement including its definition, staging, and treatment strategies. Chinse expert Consensus on Surgical Treatment of Adenocarcinoma of Esophagogastric Junction in China (2018 Edition) had been released in September 2018 and had played a pioneering role in unifying thoracic and general surgeons in China on surgical treatment strategies for AEG. Over the past five years, the emergence of several clinical research results on AEG has provided new clinical evidence for the selection of key surgical treatment strategies. Therefore, to further standardize the surgical treatment of AEG in China, Chinese Expert Consensus on Surgical Treatment of Adenocarcinoma of Esophagogastric Junction in China (2024 Edition) was released in 2024 by Chinese expert panel including 25 gastrointestinal surgeons and 24 thoracic surgeons. Based on the highest-level clinical research evidence in recent 5 years, this consensus ultimately formulates 29 recommendations on hotspots and key points on surgical treatment of AEG and summary 5 issues that are still awaiting further exploration. This review will provide a summary and detailed interpretation of the recommendations outlined in this consensus.

[Updates of colonoscopy surveillance guidelines after screening and polypectomy, and related research progress]

With the widespread application of colorectal cancer screening, the surveillance and management of the increasing number of screened population has become a pivotal aspect in preventing and controlling colorectal cancer. In recent years, researches have been conducted on the risk of colorectal cancer incidence and mortality in the population after screening. At the same time, various organizations in Europe and the United States have continuously updated colonoscopy surveillance after screening and polypectomy based on the latest research evidence. In this review, we summarized the current progress of studies on colorectal cancer risk in post-screening colorectal cancer populations and the key points of relevant guideline updates, in order to provide a reference for conducting relevant studies and formulating surveillance guidelines or consensus in China.

[Clinicopathological characteristics and prognosis of patients with small bowel tumors: A single center analysis of 220 cases]

Objective: To analyze the clinicopathological characteristics and prognosis of patients with small bowel tumors. Methods: This was a retrospective, observational study. We collected clinicopathological data of patients with primary jejunal or ileal tumors who had undergone small bowel resection in the Department of Gastrointestinal Surgery, West China Hospital, Sichuan University between January 2012 and September 2017. The inclusion criteria included: (1) older than 18 years; (2) had undergone small bowel resection; (3) primary location at jejunum or ileum; (4) postoperative pathological examination confirmed malignancy or malignant potential; and (5) complete clinicopathological and follow-up data. Patients with a history of previous or other concomitant malignancies and those who had undergone exploratory laparotomy with biopsy but no resection were excluded. The clinicopathological characteristics and prognoses of included patients were analyzed. Results: The study cohort comprised 220 patients with small bowel tumors, 136 of which were classified as gastrointestinal stromal tumors (GISTs), 47 as adenocarcinomas, and 35 as lymphomas. The median follow-up for all patient was 81.0 months (75.9-86.1). GISTs frequently manifested as gastrointestinal bleeding (61.0%, 83/136) and abdominal pain (38.2%, 52/136). In the patients with GISTs, the rates of lymph node and distant metastasis were 0.7% (1/136) and 11.8% (16/136), respectively. The median follow-up time was 81.0 (75.9-86.1) months. The 3-year overall survival (OS) rate was 96.3%. Multivariate Cox regression-analysis results showed that distant metastasis was the only factor associated with OS of patients with GISTs (HR=23.639, 95% CI: 4.564-122.430, P<0.001). The main clinical manifestations of small bowel adenocarcinoma were abdominal pain (85.1%, 40/47), constipation/diarrhea (61.7%, 29/47), and weight loss (61.7%, 29/47). Rates of lymph node and distant metastasis in patients with small bowel adenocarcinoma were 53.2% (25/47) and 23.4% (11/47), respectively. The 3-year OS rate of patients with small bowel adenocarcinoma was 44.7%. Multivariate Cox regression-analysis results showed that distant metastasis (HR=4.018, 95%CI: 2.108-10.331, P<0.001) and adjuvant chemotherapy (HR=0.291, 95% CI: 0.140-0.609, P=0.001) were independently associated with OS of patients with small bowel adenocarcinoma. Small bowel lymphoma frequently manifested as abdominal pain (68.6%, 24/35) and constipation/diarrhea (31.4%, 11/35); 77.1% (27/35) of small bowel lymphomas were of B-cell origin. The 3-year OS rate of patients with small bowel lymphomas was 60.0%. T/NK cell lymphomas (HR= 6.598, 95% CI: 2.172-20.041, P<0.001) and adjuvant chemotherapy (HR=0.119, 95% CI: 0.015-0.925, P=0.042) were independently associated with OS of patients with small bowel lymphoma. Small bowel GISTs have a better prognosis than small intestinal adenocarcinomas (P<0.001) or lymphomas (P<0.001), and small bowel lymphomas have a better prognosis than small bowel adenocarcinomas (P=0.035). Conclusions: The clinical manifestations of small intestinal tumor are non-specific. Small bowel GISTs are relatively indolent and have a good prognosis, whereas adenocarcinomas and lymphomas (especially T/NK-cell lymphomas) are highly malignant and have a poor prognosis. Adjuvant chemotherapy would likely improve the prognosis of patients with small bowel adenocarcinomas or lymphomas.

[Network meta-analysis comparing the clinical outcomes and safety of robotic, laparoscopic, and transanal total rectal mesenteric resection for rectal cancer]

Objective: To methodically assess the clinical effectiveness and safety of robot-assisted total rectal mesenteric resection (RTME), laparoscopic-assisted total rectal mesenteric resection (laTME), and transanal total rectal mesenteric resection (taTME). Methods: A computer search was conducted on PubMed, Embase, Cochrane Library, and Ovid databases to identify English-language reports published between January 2017 and January 2022 that compared the clinical efficacy of the three surgical procedures of RTME, laTME, and taTME. The quality of the studies was evaluated using the NOS and JADAD scales for retrospective cohort studies and randomized controlled trials, respectively. Direct meta-analysis and reticulated meta-analysis were performed using Review Manager software and R software, respectively. Results: Twenty-nine publications comprising 8,339 patients with rectal cancer were ultimately included. The direct meta-analysis indicated that the length of hospital stay was longer after RTME than after taTME, whereas according to the reticulated meta-analysis the length of hospital stay was shorter after taTME than after laTME (MD=-0.86, 95%CI: -1.70 to -0.096, P=0.036). Moreover, the incidence of anastomotic leak was lower after taTME than after RTME (OR=0.60, 95%CI: 0.39 to 0.91, P=0.018). The incidence of intestinal obstruction was also lower after taTME than after RTME (OR=0.55, 95%CI: 0.31 to 0.94, P=0.037). All of these differences were statistically significant (all P<0.05). There were no statistically significant differences between the three surgical procedures regarding the number of lymph nodes cleared, length of the inferior rectal margin, or rate of positive circumferential margins (all P>0.05). An inconsistency test using nodal analysis revealed no statistically significant differences between the results of direct and indirect comparisons of the six outcome indicators (all P>0.05). Furthermore, we detected no significant overall inconsistency between direct and indirect evidence. Conclusion: taTME has advantages over RTME and laTME, in terms of radical and surgical short-term outcomes in patients with rectal cancer.

[Expression of PD-L1 and tumor infiltrating lymphocyte markers in uterine cervical carcinoma]

Objective: To investigate the expression of PD-L1, CD4, CD8 and CXCL-13 in cervical carcinoma, and their clinicopathological significance was analyzed. Methods: A total of 77 patients with cervical carcinoma in the Seventh Medical Center, PLA General Hospital from January 2019 to December 2021 were included. All patients received radical surgical resection in the Seventh Medical Center of Chinese PLA General Hospital. The expression of PD-L1, CD4, CD8 and CXCL-13 was detected by immunohistochemical (IHC) method. The correlation between IHC markers and patients' clinicopathological parameters was analyzed. Results: There were 59 cases of squamous cell carcinoma and 18 cases of adenocarcinoma (ranging from 29 to 69 years) with an average of (49.4±9.8) years. PD-L1 was expressed in different degrees in cervical squamous cell carcinoma and adenocarcinoma (χ²=4.975, P=0.026); CD4⁺, CD8⁺and CXCL-13⁺tumor infiltrating lymphocytes (TIL) were observed in the carcinoma cell nests and peritumoral stroma. PD-L1 expression in cervical carcinoma was moderately correlated with the number of CD4⁺TIL in the carcinoma nests, and the number of CD8⁺, CXCL-13⁺TIL infiltration in the carcinoma nests and stroma, but not to the patient's age, histologic differentiation, presence or absence of vascular invasion, presence or absence of lymph node metastasis and FIGO stage (P>0.05). Conclusions: The high expression of PD-L1 in cervical carcinoma tissues is closely related to the number of TIL in the carcinoma nests and peritumor stroma, suggesting that they may have important reference value for predicting the response to immunotherapy in patients with cervical carcinoma.

[Characteristics of SARS-CoV-2 Omicron infection in children imported from Hong Kong]

Objective: To understand the clinical characteristics of children with SARS-CoV-2 Omicron infection imported from Hong Kong Special Administrative Region. Methods: This retrospective study was conducted to collect the data including clinical manifestations, outcomes and vaccination of 107 children with SARS-CoV-2 Omicron infection imported from Hong Kong Special Administrative Region to be admitted to the designated referral hospital in Shanghai from February to March 2022. According to the occurrence of clinical symptoms, the cases were divided into asymptomatic group and symptomatic group. According to the age of diagnosis, the cases were divided into <3 years group, 3-<6 years group and 6-<18 years group, and the clinical manifestations in different age group were analyzed with t-test and Mann-Whitney rank-sum test. Besides, to analyze the effectiveness of vaccination against SARS-CoV-2 Omicron infection in different age group, the cases aged 3-<18 years were also subdivided into unvaccinated group, 1-dose group and 2-dose group, and the relative risk (RR) was used to demonstrate the effectiveness. Results: Among the 107 cases, 66 were male and 41 were female, with infection age of 10 (5, 14) years. There were 29 cases in the asymptomatic group, and 78 cases in the symptomatic group, and no significant difference in the age of infection was observed between the 2 groups (11 (6, 14) vs. 10 (5, 14) years, Z=0.49, P>0.05). And there were no severe cases in symptomatic group. The length of hospitalization was (18±6) days, and was longer in symptomatic group than that in asymptomatic group ((19±6) vs. (16±7) d, t=0.17, P=0.030). Eight-two cases (76.6%) had a history of epidemiological exposure and, among whom, 81 cases (75.7%) were associated with household transmission. Among symptomatic group, 57 cases (73.1%) had fever and 20 cases (25.6%) had cough. Of the 74 cases undergoing chest CT examination, 17 cases (23.0%) showed mild abnormalities. Of the 83 cases who received the lab tests, 23 cases (27.7%) had white blood cell counts<4×10⁹/L, 3 cases (3.6%) had C-reaction protein >8.0 mg/L, and 6 cases (7.2%) had slightly elevated aspartate transaminase and alanine aminotransferase. Among the 92 children aged 3-<18 years, 31 cases were unvaccinated, 34 cases received 1 dose, and 27 cases received 2 doses. The interval between the last vaccination and infection was 2.2 (0.6, 6.0) months; the interval between the last vaccination and infection in the 2-dose group was longer than that in 1-dose group (6.0 (4.5, 7.3) vs. 0.7 (0.3,2.0) months, Z=3.59, P<0.001).The risk of symptomatic infection was reduced by 45% (RR=0.55, 95% CI 0.35-0.87) with two-dose vaccination compared to non-vaccination in cases aged 3-<18 years. All these cases recovered completely. Conclusions: Children infected with SARS-CoV-2 Omicron are usually mild or asymptomatic. Household transmission is the main pattern of infection with SARS-CoV-2 Omicron in children. Two-dose SARS-CoV-2 vaccination in children aged 3-<18 years can provide partial protection against disease caused by SARS-CoV-2 Omicron.

[Molluscicidal effect of immersion with 50% wettable powder of niclosamide ethanolamine salt against Oncomelania hupensis on the soil surface and inside the soil layer in winter]

OBJECTIVE

To evaluate the molluscicidal effect of 50% wettable powder of niclosamide ethanolamine salt (WPNES) against Oncomelania hupensis on the soil surface and inside the soil layer by immersion method in winter.

METHODS

O. hupensis snails were placed on the soil surface and 2, 5 cm and 10 cm under the soil layer outdoors in winter, and then immersed in 50% WPNES at concentrations of 1 mg/L and 2 mg/L for 1, 3 d and 7 d, while dechlorinated water served as controls. Snail mortality was observed following immersion with 50% WPNES on the soil surface and inside the soil layer.

RESULTS

Following immersion with 50% WPNES at concentrations of 2 mg/L and 1 mg/L outdoors in winter, the 3-day corrected snail mortality rates were 98.0% and 76.0% on the soil surface, and the 7-day corrected snail mortality rate was both 100.0%. Following immersion with 50% WPNES at concentrations of 2 mg/L and 1 mg/L outdoors in winter, the 7-day corrected snail mortality rates were 95.5% and 85.6% 2 cm below the soil layer, 66.0% and 6.4% 5 cm below the soil layer. However, the 7-day snail mortality rate swere comparable between the 50% WPNES treatment group (at 2 mg/L and 1 mg/L) and controls 10 cm below the soil layer (both P > 0.05).

CONCLUSIONS

Immersion of 50% WPNES at a concentration of 2 mg/L for 7 days presents a high molluscicidal efficacy against O. hupensis on the soil surface and 5 cm within the soil layers in winter.

[Mental health status and its influencing factors of nurses in geriatric department after workplace violence]

Objective: To investigate the mental health status and influencing factors of geriatric nurses after workplace violence. Methods: From February 2019 to January 2020, 102 geriatric nurses who suffered workplace violence in three hospitals in Shaoxing were collected as the observation group and 100 geriatric nurses who did not suffer workplace violence in the same period as the control group. The general data of nurses in the two groups were investigated, the workplace violence was investigated with the hospital workplace violence questionnaire, the mental disorders and mental diseases were investigated with the symptom checklist 90 (SCL-90) , the symptoms of post-traumatic stress disorder were investigated with the symptom checklist of post-traumatic stress disorder (pcl-c) , and the psychological elasticity was investigated with the psychological elasticity scale, Social support was investigated with social support scale (SSRs) . Results: The total average score of symptom checklist 90 (SCL-90) of nurses with workplace violence was (1.49 ± 0.48) . Compared with the control group, the total average score of SCL-90, somatization, obsessive-compulsive symptoms, depression, anxiety and fear factors in the observation group were significantly increased (P<0.05) . The total score of post-traumatic stress disorder symptom list (pcl-c) in the observation group was (34.51±9.87) . Compared with the control group, the total average score of pcl-c, re experience, avoidance and vigilance factors in the observation group were significantly increased (P<0.05) . The total average score of SCL-90 of nurses with workplace violence was positively correlated with psychological elasticity and social support (P<0.05) . Multivariate linear analysis showed that psychological elasticity, tenacity and control, optimism, social support and subjective support were the main factors affecting nurses＇mental health. Conclusion: Geriatric nurses suffering from workplace violence are prone to mental health problems and post-traumatic stress disorder, which should be improved by improving their psychological elasticity and social support.

[Consistency of peripheral whole blood and venous serum procalcitonin in children: a multicenter parallel controlled study]

Objective: To explore the consistency of peripheral whole blood and venous serum procalcitonin (PCT) levels, and the value of peripheral whole blood PCT in evaluating pediatric bacterial infection. Methods: This multicenter cross-sectional parallel control study was conducted in 11 children's hospital. All the 1 898 patients older than 28 days admitted to these hospitals from March 2018 to February 2019 had their peripheral whole blood and venous serum PCT detected simultaneously with unified equipment, reagent and method. According to the venous serum PCT level, the patients were stratified to subgroups. Analysis of variance and chi-square test were used to compare the demographic characteristics among groups. And the correlation between the peripheral blood and venous serum PCT level was investigated by quantitative Pearson correlation analysis.The PCT resultes were also converted into ranked data to further test the consistency between the two sampling methods by Spearman's rank correlation test. Furthermore, the ranked data were converted into binary data to evaluate the consistency and investigate the best cut-off of peripheral blood PCT level in predicting bacterial infection. Results: A total of 1 898 valid samples were included (1 098 males, 800 females),age 27.4(12.2,56.7) months. There was a good correlation between PCT values of peripheral whole blood and venous serum (r=0.97, P<0.01). The linear regression equation was PCT_{venous serum}=0.135+0.929×PCT_{peripheral whole blood}. However, when stratified to 5 levels, PCT results showed diverse and unsatisfied consistency between the two sampling methods (r=0.51-0.92, all P<0.01). But after PCT was converted to ordinal categorical variables, the stratified analysis showed that the coincidence rate of the measured values by the two sampling methods in each boundary area was 84.9%-97.1%. The dichotomous variables also showed a good consistency (coincidence rate 96.8%-99.3%, Youden index 0.82-0.89). According to the severity of disease, the serum PCT value was classified into 4 intervals（<0.5、0.5-<2.0、2.0-<10.0、≥10.0 μg/L）, and the peripheral blood PCT value also showed a good predictive value (AUC value was 0.991 2-0.997 9). The optimal cut points of peripheral whole blood PCT value 0.5、1.0、2.0、10.0 μg/L corresponding to venous serum PCT values were 0.395, 0.595, 1.175 and 3.545 μg/L, respectively. Conclusions: There is a good correlation between peripheral whole blood PCT value and the venous serum PCT value, which means that the peripheral whole blood PCT could facilitate the identification of infection and clinical severity. Besides, the sampling of peripheral whole blood is simple and easy to repeat.

[Surveillance of Oncomelania hupensis distribution and water levels in Gaoyou sections of the eastern route project of the South-to-North Water Diversion Project following operation of the project]

OBJECTIVE

To understand the distribution of Oncomelania hupensis snails and changes of water levels in Gaoyou sections of the Li Canal following the operation of the eastern route project of the South-to-North Water Diversion Project.

METHODS

The Oncomelania snails were monitored in the river banks and water bodies of Gaoyou sections of the Li Canal by means of systematic sampling combined with environmental sampling as well as collection of the floaters from 2014 to 2019, and the water levels were collected in Gaoyou sections of the Li Canal at the typical hydrological year before the operation of the eastern route project of the South-to-North Water Diversion Project and during the period between 2016 and 2019.

RESULTS

A total area of 235.42 hm² were investigated and a total of 75.8 kg floaters were collected in Gaoyou sections of the Li Canal from 2014 to 2019; however, no snails were found. The water level in Gaoyou sections of the Li Canal was predominantly high in the flood season and low in the dry season before the operation of the eastern route project of the South-to-North Water Diversion Project, and the water level was elevated in the dry season and relatively low in the flood season after the operation of the project.

CONCLUSIONS

Following the operation of the eastern route project of the South-to-North Water Diversion Project, the original river bank that is characterized by "land in winter and water in summer" has changed in Gaoyou sections of the Li Canal, which is not favorable for snail breeding.

[Does age affect the hidden blood loss of elderly intertrochanteric fracture patients fixed with combined external fixator?]

Objective: To evaluate the postoperatively hidden blood loss of elderly intertrochanteric fracture patients fixed with combined external fixator, and to explore the correlation between hidden blood loss and age. Methods: A retrospective analysis was conducted on 60 elderly intertrochanteric fracture patients who were admitted to the Department of Orthopedics of Hebei Provincial Hospital from January 2016 to May 2019. All the fractures were fixed with combined external fixators. The patients were divided into two groups according to the age: there were 31 cases in group A (60-80 years old) and 29 cases in group B (≥80 years old). The Gross equation and the Nandler formula were used to evaluate the amount of hidden blood loss based on changes in hematocrit (Hct) at the day preoperatively, 3 days postoperatively and the weight. The data were compared between the two groups by independent-sample t test. Results: The decreased Hct, hemoglobin(Hb) and the dominant blood loss and hidden blood loss in group A and B was 3.4%±1.7%, (13±7) g/L, (25±6) ml, (186±7) ml and 3.8%±1.2%, (13±3) g/L, (24±8) ml, (194±7) ml, respectively. There was no significant differences in the dominant and hidden blood loss between the groups (t=0.309, 0.883, both P>0.05). Conclusion: The age doesn't affect the hidden blood loss in elderly intertrochanteric fracture patients fixed with combined external fixator, which indicated that the operation is safe and reliable for such patients.

[Analysis of screening strategy of group B streptococcus in the third trimester and its influence on pregnancy outcome]

Objective: To investigate the screening strategy of group B streptococcus (GBS) in the reproductive tract of women in the third trimester and analyze its impact on pregnancy outcome. Methods: A total of 85 461 pregnant women in 35-37 weeks of gestation from Bao'an Maternity and Child Health Hospital, Jinan University from January 2011 to June 2018 were enrolled. They were divided into 3 periods according to different GBS screening strategies, the unscreened period included 31 384 cases (36.72%), 33 267 cases (38.93%) were included in partial screening period, 20 810 cases (24.35%) were included in screening period. All GBS screening positive pregnant women were given intrapartum antibiotic prophylaxis (IAP). The impact on pregnancy outcomes, and the impact of different GBS collection transport and culture methods on the positive rate of GBS screening were analyzed. Results: (1) The incidence of neonatal early onset GBS disease (EOGBSD) in unscreened period was 0.03% (11/31 773), in partial screening period was 0.02%(6/33 887), and in screening period, the incidence of neonatal EOGBSD decreased to 0, the difference was statistically significant (χ(2)=7.86, P=0.02).(2) The incidence of hematogenous infection of GBS in pregnant women was 0.02%(6/33 887) in partial screening period, and there was none in screening period, there was no significant difference (adjusted χ(2)=3.75, P=0.05). (3) In the screening period, the positive rate of GBS was 14.08%(2 719/19 306), which was significantly higher than the positive rate of GBS in the partial screening period (11.48%, 2 058/17 920; χ(2)=56.12, P=0.00). (4) Antibiotic sensitivity tests of 4 777 GBS strains showed that the antibiotics with higher resistance rate were tetracycline (81.52%, 3 896/4 777), erythromycin (66.59%, 3 181/4 777), and clindamycin (64.31%, 3 072/4 777). The combination of erythromycin, clindamycin and tetracycline was the most common resistant pattern, accounting for 48.80% (2 331/4 777). No penicillin, ceftriaxone or vancomycin resistant strains was found. Conclusions: GBS screening strategy in different regions could combine the local neonatal EOGBSD incidence rate, maternal GBS colonization rate, and the socioeconomic factors to determine whether universal GBS screening or screening for high-risk maternal women. GBS screening positive rate is related to the population, scope of the investigation, the sample collection, delivery and culture methods. The multi-drug resistance rate of GBS is high.

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

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

Transcriptome characterization of HPG axis from Chinese sea perch Lateolabrax maculatus

Here the transcriptome and differential gene expression in the adult brain and gonads of the Chinese sea perch Lateolabrax maculatus were reported. A total of 78 256 909 clean reads were generated from the adult brain, ovary and testis by using the Illumina HiSeq2000 platform and assembled into 274 909 contigs. A total of 31 683 unigenes were annotated based on sequence similarity and 20 702 unigenes were found to exhibit 8237 gene ontology terms and 3888 signal pathways. Transcripts of 26 623 unigenes were present in all of the tissues, whereas pairwise comparisons revealed that 671/367, 496/315 and 1668/580 unigenes were up-down regulated by at least two-fold between the brain and ovary, ovary and testis and brain and testis, respectively. Homology search led to the identification of reproduction-associated genes of the brain-gonad axis, including those involved in sex differentiation and maintenance. The data provided an integrated and comprehensive transcriptome resource for L. maculatus, which could be used for further research on hypothalamus-pituitary-gonad axis gene function, reproduction regulation and sex-biased gene expression.

[Effects of temperature increase on zooplankton size spectra in thermal discharge seawaters near a power plant, China]

Utilizing the plankton 1 (505 Μm), 2 (160 Μm), 3 (77 Μm) nets to seasonally collect zooplankton samples at 10 stations and the corresponding abundance data was obtained. Based on individual zooplankton biovolume, size groups were classified to test the changes in spatiotemporal characteristics of both Sheldon and normalized biovolume size spectra in thermal discharge seawaters near the Guohua Power Plant, so as to explore the effects of temperature increase on zooplankton size spectra in the seawaters. The results showed that the individual biovolume of zooplankton ranged from 0.00012 to 127.0 mm³·ind^-1, which could be divided into 21 size groups, and corresponding logarithmic ranges were from -13.06 to 6.99. According to Sheldon size spectra, the predominant species to form main peaks of the size spectrum in different months were Copepodite larvae, Centropages mcmurrichi, Calanus sinicus, fish larvae, Sagitta bedoti, Sagitta nagae and Pleurobrachia globosa, and minor peaks mostly consisted of individuals with smaller larvae, Cyclops and Paracalanus aculeatus. In different warming sections, Copepodite larvae, fish eggs and Cyclops were mostly unaffected by the temperature increase, while the macrozooplankton such as S. bedoti, S. nagae, P. globosa, C. sinicus and Beroe cucumis had an obvious tendency to avoid the outfall of the power plant. Based on the results of normalized size spectra, the intercepts from low to high occurred in November, February, May and August, respectively. At the same time, the minimum slope was found in February, and similarly bigger slopes were observed in May and August. These results indicated that the proportion of small zooplankton was highest in February, while the proportions of the meso- and macro-zooplankton were relatively high in May and August. Among different sections, the slope in the 0.2 km section was minimum, which increased with the increase of section distance to the outfall. The result obviously demonstrated that the closer the distance was from outfall of the power plant, the smaller the zooplankton became. On the whole, the average intercept of normalized size spectrum in Xiangshan Bay was 4.68, and the slope was -0.655.

Stimulus-induced pacemaker activity in interstitial cells of Cajal associated with the deep muscular plexus of the small intestine

BACKGROUND

The ICC-DMP have been proposed to generate stimulus-dependent pacemaker activity, rhythmic transient depolarizations, that take part in orchestrating segmentation and clustered propulsive motor patterns in the small intestine. However, little is known about the fundamental properties of ICC-DMP.

METHODS

This study was undertaken to increase our understanding of intrinsic properties of the ICC-DMP through calcium imaging and intracellular electrical recordings.

KEY RESULTS

Without stimulation, most ICC-DMP were quiescent. In some preparations ICC-DMP generated rhythmic low-frequency calcium oscillations (<10 cpm) with or without high frequency activity superimposed (>35 cpm). Immunohistochemistry proved the existence of NK1R on the ICC-DMP and close contacts between ICC-DMP and substance P-positive nerves. Substance P (25 nM) induced low-frequency calcium oscillations that were synchronized across the ICC-DMP network. Substance P also induced low frequency rhythmic transient depolarizations (<10cpm) in circular muscle cells close to the ICC-DMP. An intracellular recording from a positively identified ICC-DMP showed rhythmic transient depolarizations with superimposed high frequency activity. To investigate if quiescent ICC-DMP were chronically inhibited by nitrergic activity, nNOS was inhibited, but without effect.

CONCLUSIONS & INFERENCES

Substance P changes non-synchronized high frequency flickering or quiescence in ICC-DMP into strong rhythmic calcium transients that are synchronized within the network; they are associated with rhythmic transient depolarizations within the same frequency range. We hypothesize that Substance P, released from nerves, can evoke rhythmicity in ICC-DMP, thereby providing it with potential pacemaker activity.

Design of Hydrogen Storage Alloys/Nanoporous Metals Hybrid Electrodes for Nickel-Metal Hydride Batteries

Nickel metal hydride (Ni-MH) batteries have demonstrated key technology advantages for applications in new-energy vehicles, which play an important role in reducing greenhouse gas emissions and the world's dependence on fossil fuels. However, the poor high-rate dischargeability of the negative electrode materials-hydrogen storage alloys (HSAs) limits applications of Ni-MH batteries in high-power fields due to large polarization. Here we design a hybrid electrode by integrating HSAs with a current collector of three-dimensional bicontinuous nanoporous Ni. The electrode shows enhanced high-rate dischargeability with the capacity retention rate reaching 44.6% at a discharge current density of 3000 mA g(-1), which is 2.4 times that of bare HSAs (18.8%). Such a unique hybrid architecture not only enhances charge transfer between nanoporous Ni and HSAs, but also facilitates rapid diffusion of hydrogen atoms in HSAs. The developed HSAs/nanoporous metals hybrid structures exhibit great potential to be candidates as electrodes in high-performance Ni-MH batteries towards applications in new-energy vehicles.

Magnetic mediation effect of a C impurity in a Mn-doped Zn₁₂O₁₂ nanocluster: a case of multiple exchange interactions

The stability and exchange interaction mechanism of a doped Zn12O12 cluster with Mn and C atoms were investigated by first-principles calculations. For the Mn-doped Zn12O12 cluster, it is identified that a superexchange interaction deriving the hybridization between the Mn 3d(2/x)-2/y and O 2p(xy) orbitals dominates the Mn(↑)-Mn(↓) antiferromagnetic coupling, although a direct exchange interaction deriving the Mn-Mn bonding is also found. In order to turn the Mn spin state in the Mn-doped Zn12O12 cluster, C doping is undertaken to change the magnetic interactions of these impurities. It is proved that the C incorporation into the Mn-doped Zn12O12 cluster destroys the short-ranged antiferromagnetic coupling, where multiple exchange interactions take over, including the direct exchange interaction and the kinetic p-d exchange interaction partially due to the geometric distortion and surface effect with dangling bonds (sp(2)-like hybrids). It is concluded that the kinetic p-d exchange interaction plays a dominant role in Mn/C-doped Zn12O12 clusters.

Copper metallization for current very large scale integration

As silicon technology scaling progresses to the 32 nm node or even further, the design on the propagation of electromagnetic signals becomes increasingly appealing due to their unyielding constraints on interconnect delay. Because of its high conductivity and electromigration resistance, Cu is now the interconnect materials in current VLSI. To ensure the signal propagation via the Cu interconnects upon the increasingly reduction in the interconnect width, related issues on Cu interconnects, such as electron scattering at surfaces and grain boundaries, electromigration failure and surface oxidation, still need to be further understood and addressed. Besides this, the performance of low-k dielectrics and reliable barrier structures, which are also much important among the device parts, are required to be further improved to minimize the signal delay and to prevent penetration of different materials, respectively. On the basis of the paper published at Recent Patent on Nanotechnology 2007; 1: 193-209, this review will focus on recent patents and some studies on Cu metallization including Cu interconnect wires, low-k dielectrics and related barrier materials as well as manufacturing techniques in VLSI, which are one of the most essential concerns in microelectronic industry and decide further development of VLSI. This review will benefit for the design of the Cu metallization in the current VLSI.

Electron scattering and electrical conductance in polycrystalline metallic films and wires: impact of grain boundary scattering related to melting point

For electrical conductance in polycrystalline metallic films and wires, the reflection coefficient of electrons at grain boundaries is explored and found to be proportional to the square root of the melting points of metals. As validated by available experimental results, this exploration enables classical models to take an essential role in theoretically predicting the electrical conductance of low-dimensional metals. One thus sees that the mechanism dominating the suppression of electrical conductance is transformed from the surface scattering into the grain boundary scattering as the ratio of film thickness (or wire diameter) to grain size rises. Furthermore, the impact of grain boundary scattering becomes less important for metals with lower melting points.

Analysis of genetic structure and relationship among nine indigenous Chinese chicken populations by the Structure program

The multi-locus model-based clustering method Structure program was used to infer the genetic structure of nine indigenous Chinese chicken (Gallus gallus) populations based on 16 microsatellite markers. Twenty runs were carried out at each chosen value of predefined cluster numbers (K) under admixture model. The Structure program properly inferred the presence of genetic structure with 0.999 probabilities. The genetic structure not only indicated that the nine kinds of chicken populations were defined actually by their locations, phenotypes or culture, but also reflected the underlying genetic variations. At K = 2, nine chicken populations were divided into two main clusters, one light-body type, including Chahua chicken (CHA), Tibet chicken (TIB), Xianju chicken (XIA), Gushi chicken (GUS) and Baier chicken (BAI); and the other heavy-body type, including Beijing You chicken (YOU), Xiaoshan chicken (XIA), Luyuan chicken (LUY) and Dagu chicken (DAG). GUS and DAG were divided into independent clusters respectively when K equaled 4, 5, or 6. XIA and BIA chicken, XIA and LUY chicken, TIB and CHA chicken still clustered together when K equaled 6, 7, and 8, respectively. These clustering results were consistent with the breeding directions of the nine chicken populations. The Structure program also identified migrants or admixed individuals. The admixed individuals were distributed in all the nine chicken populations, while migrants were only distributed in TIB, XIA and LUY populations. These results indicated that the clustering analysis using the Structure program might provide an accurate representation of the genetic relationship among the breeds.

Synthesis of hierarchical pure ZnO nanostructures with controllable morphology

Hierarchical pure ZnO nanostructures with controllable morphology were synthesized by two-step oxygen-controlled thermal evaporation method without any catalyst. Zn nanowires with little oxidation were deposited firstly on Si substrates located at the low temperature area at step one. The morphology of hierarchical ZnO nanostructures can be effectively modulated at step two by oxygen flow rate, taking advantage of the controllable oxidation rate of Zn and concentration of ZnO(x) under various oxygen supplies. Transmission electron microscope images and corresponding selected area electron diffraction patterns suggest that low oxygen supplementation causes the epitaxial growth of nanorods from the surface of the Zn nanowire, while high oxygen flow rate will lead to the preferential growth of nanorods along the [001] orientation. Room-temperature photoluminescence measurements demonstrate that the variety of nanostructures can cause the variation of the ultraviolet to green peak intensity ratio, suggesting that the controlled morphologies can be used to modulate the optical properties of ZnO nanostructures.

Chemical conversion synthesis and optical properties of metal sulfide hollow microspheres

A facile chemical conversion method has been demonstrated to prepare various metal sulfide hollow microspheres. The present strategy utilizes the large difference in solubility between ZnS and other metal sulfides (Ag2S, PbS, CuS, Cu2S, Bi2S3, and Sb2S3) for the effective transformation and shows mild growth conditions and good reproducibility. The morphology, structure, and composition of the yielded hollow nanostructures have been confirmed by transmission electron microscopy, energy-dispersive X-ray analysis, and X-ray diffraction measurements. The optical properties of the metal sulfide hollow microspheres have been systematically investigated by absorption, micro-Raman, and photoluminescence spectroscopy. The results demonstrate that these metal sulfide hollow microspheres possess good optical quality with tunable band gaps and luminescence properties, which indicate their broad potential applications. This simple chemical conversion technique can be further extended to the synthesis of other semiconductors with various morphologies.

Nature of solidification of nanoconfined organic liquid layers

A simple model is established for solidification of a nanoconfined liquid under nonequilibrium conditions. In terms of this model, the nature of solidification is the conjunct finite size and interface effects, which is directly related to the cooling rate or the relaxation time of the undercooled liquid. The model predictions are consistent with available experimental results.

A rat model of chronic allograft liver rejection

INTRODUCTION

The aim of this study was to develop a rat model of chronic irreversible rejection, which is a major causes of late graft loss and retransplantation after orthotopic liver allotransplantation.

METHODS

Allogeneic liver transplantation was performed in a rat combination of Dark Agouti (DA) to Brown Norway (BN). Group A was left without treatment, group B received cyclosporine' (CsA; 1 mg/kg/d) and group C, CsA (4 mg/kg/d). Animals were followed for 6 months. Liver tissue was harvested to construct a time course of histological changes after liver transplantation using histopathological and morphometric techniques. We compared the total histological score of rejection activity index and survival rates.

RESULTS

In untreated animals, irreversible acute rejection developed, all animals died within 15 days. In the low-dose CsA group, all animals that survived more than 30 days developed moderate to severe manifestations of chronic liver rejection, with graft infiltration, ductular damage or proliferation, obliterative arteriopathy, and liver fibrosis. No apparent histological alterations were observed in group C. Survival analysis showed significant differences between the three groups.

CONCLUSIONS

In the rat strain combination of DA --> BN with low-dose immunosuppression, early mild inflammation was followed by the development of chronic rejection.

[HLA-DRB1 gene polymorphism of Naxi ethnic group of Yunnan Province, China and its ethnological evolution analysis]

The HLA-DRB1 gene polymorphism of Naxi ethnic group of Yunnan Province, China was investigated for the first time using high resolution PCR-SBT method, which is based on sequences of HLA-DRB1 Intron 1 and Intron 2 with our improvement. From 60 individuals of Naxi 37 DRB1 alleles were detected. The distribution of allele frequencies is evenly spread for most of alleles detected in Naxi. However, the gene frequency for HLA-DRB1 * 12021 is 17.50%. The other common alleles (> 5%) were HLA-DRB1 * 1404(7.50%), 1504(5.83%), 04051(5.83%), 08032(5.83%), 09012(5%), 03011(5%), and they covered 35% of the total alleles detected from Naxi, and 52.49% after adding the frequency of HLA-DRB1 * 12021. HLA-DRB1 * 0305, 0438, 1123, 1132, 1310, 0812 were detected in Chinese for the first time, and were very rare in other ethnic groups worldwide. Using the HLA-DRB1 gene frequencies of various ethnic groups, we constructed the phylogenetic tree by Fitch-Margoliash and Least-Squares Distance Methods and Cavalli-Sforza's chord measure of genetic distance. In our dendrogram, the South China populations were clustered together, and Siberian, Japanese and Minority of North China were clustered together, in which two big clusters we thought represented the ancient Southern and Northern Mongolian. Our results showed Naxi was clustered with Lahu and Yao ethnic groups, which were in the cluster of South China population. Obviously Naxi belongs to the South China ethnic groups and can't trace its origin from northern ethnic groups with the HLA-DRB1 genetic data. But based on Naxi's historical folklore, it was down to Southern China from Northwest China. The preliminary analysis about its origin conundrum was discussed in this paper based on our genetic data in relationship with its history and ethnology studies.

[Effect of alcohol extract of Cornus officinalis Sieb. et Zucc on GLUT4 expression in skeletal muscle in type 2 (non-insulin-dependent) diabetic mellitus rats]

OBJECTIVE

Based on its effects of decreasing postprandial plasma glucose and increasing insulin level in non-insulin-dependent diabetic mellitus (NIDDM) rats, we studied the effects of Alcohol extract of Cornus officinalis Sieb. et Zucc on the GLUT4 expression in NIDDM model rats.

METHOD

The rat model of NIDDM was made. The animals were divided into three groups(six for each group): group I: control; group II: NIDDM model; group III: NIDDM model + Cornus officinalis Sieb. et Zucc. The drug was given orally to animals one time a day, uninterrupted for a month. The GLUT4 mRNA and its protein expression in skeletal muscle were observed with Northern blot and Western blot method, respectively.

RESULT

The GLUT4 mRNA expression in skeletal muscle was decreased remarkably in NIDDM rats (P < 0.01, compared to control group). Alcohol extract of Cornus officinalis Sieb. et Zucc increased GLUT4 mRNA expression in NIDDM rats(P < 0.01), compared to NIDDM model group). The result of GLUT4 protein expression was similar to GLUT4 mRNA expression.

CONCLUSION

This experiment demonstrated that alcohol extract of Cornus officinalis Sieb. et Zucc can increase GLUT4 mRNA and its protein expression in NIDDM rats through promoting proliferation of islet and increasing postprandial secretion of insulin and therefore accelerate glucose transport.

Discovery of a series of nonpeptide small molecules that inhibit the binding of insulin-like growth factor (IGF) to IGF-binding proteins

Insulin-like growth factors (IGF-I and II) play an important role in metabolic and mitogenic activities through stimulation of the IGF-I receptor on the cell surface. Although the concentration of IGF in blood and cerebrospinal fluid is quite high (>100 nM), this large pool of IGF is biologically inactive because of its association with six distinct binding proteins, which form high-affinity complexes with IGF. Thus, inhibitors of IGF-binding proteins (IGFBPs), especially IGFBP-3, could potentially alter the distribution between the "free" and "bound" forms of IGF and thereby elevate biologically active IGF-I to exert a beneficial effect on those patients with diseases that respond to the application of exogenous IGF-I. Whereas IGF-I peptide variants, which bind to IGFBPs but not the IGF-I receptor, have been shown to be potent IGF/IGFBP inhibitors, small molecule nonpeptide IGF/IGFBP inhibitors have the potential advantages of oral bioavailability and flexible dosing regimen. Here we report the discovery of several isoquinoline analogues, exemplified by 1 and 2, which bind IGFBP-3 as well as other IGFBPs at low nanomolar concentrations. More importantly, both compounds were shown to be able to release biologically active IGF-I from the IGF-I/IGFBP-3 complex. These results point to the feasibility of developing orally active therapeutics to treat IGF-responsive diseases by optimization of the lead molecules 1 and 2.

Identification of a nonpeptide ligand that releases bioactive insulin-like growth factor-I from its binding protein complex

Insulin-like growth factor-I (IGF-I) has both metabolic and mitogenic activities mediated through interaction with the type 1 IGF receptor. The circulation of IGF-I in blood and interstitial fluid is not free but bound mostly to a family of six high affinity IGF-binding proteins, which form stable complexes with IGF and neutralize its bioactivity. Therefore, displacement of this large pool of endogenous IGF from the binding proteins could elevate "free" IGF levels to elicit beneficial effects in diabetes and other IGF-responsive diseases comparable with those produced by administration of exogenous IGF-I. We report here the identification of a nonpeptide ligand NBI-31772, which displaces IGF-I from all six IGF-binding proteins at low nanomolar concentrations from screening of the in-house chemical libraries. Furthermore, the released free IGF-I was shown to be biologically active in an in vitro bioassay. Thus, NBI-31772 could serve as a valuable lead molecule for the design of novel therapeutics to treat diabetes and other IGF-responsive diseases.

A cytoplasmic RNA vector derived from nontransmissible Sendai virus with efficient gene transfer and expression

We have recovered a virion from defective cDNA of Sendai virus (SeV) that is capable of self-replication but incapable of transmissible-virion production. This virion delivers and expresses foreign genes in infected cells, and this is the first report of a gene expression vector derived from a defective viral genome of the Paramyxoviridae. First, functional ribonucleoprotein complexes (RNPs) were recovered from SeV cloned cDNA defective in the F (envelope fusion protein) gene, in the presence of plasmids expressing nucleocapsid protein and viral RNA polymerase. Then the RNPs were transfected to the cells inducibly expressing F protein. Virion-like particles thus obtained had a titer of 0.5 x 10(8) to 1. 0 x 10(8) cell infectious units/ml and contained F-defective RNA genome. This defective vector amplified specifically in an F-expressing packaging cell line in a trypsin-dependent manner but did not spread to F-nonexpressing cells. This vector infected and expressed an enhanced green fluorescent protein reporter gene in various types of animal and human cells, including nondividing cells, with high efficiency. These results suggest that this vector has great potential for use in human gene therapy and vaccine delivery systems.

Progress towards the development of non-peptide orally-active gonadotropin-releasing hormone (GnRH) antagonists: therapeutic implications

Gonadotropin-releasing hormone (GnRH) is a decapeptide (pGlu-His-Trp-Ser-Tyr-Gly-Leu-Arg-Pro-Gly.NH2) which is produced from a precursor polypeptide in hypothalamic neurons and secreted in a pulsatile fashion to stimulate the secretion of LH and FSH via its interaction with a cognate receptor on gonadotropes. Low doses of the native peptide delivered in a pulsatile manner to mimic that found in the hypothalamic portal vessels restore fertility in hypogonadal patients, and are also effective in treating cryptorchidism and delayed puberty. Administration of high doses of GnRH, or agonist analogues, causes desensitization of the gonadotrope with consequent decline in gonadal gametogenesis and steroid and peptide hormone synthesis. This phenomenon finds extensive therapeutic application in clinical medicine in a wide spectrum of disease (Table 1). In addition, GnRH analogues have promise as new generation male and female contraceptives in conjunction with steroid hormone replacement. GnRH antagonists inhibit the reproductive system through competition with endogenous GnRH for the receptor and, in view of their rapid effects, are being increasingly used for the above mentioned applications. The peptide agonists and antagonists currently available require parenteral administration, typically in the form of long-acting depots. A new generation of non-peptide GnRH antagonists are beginning to emerge which should allow oral administration and, therefore, may provide greater flexibility of dosing, lower costs and increased patient acceptance.

In situ investigation of Fas/FasL expression in chronic hepatitis B infection and related liver diseases

To evaluate Fas/FasL expression in hepatitis B virus-related chronic liver disease, liver biopsies from 44 such cases were studied immunohistochemically. FasL was detected in the infiltrating lymphocytes and both FasL and Fas were found in the hepatocytes. The Fas and FasL-positive cells were mostly found at the advancing edges of interphase hepatitis, and Fas/FasL expression was closely correlated with the inflammatory activity. Unexpectedly, FasL was also expressed in liver cirrhotic nodules, particularly in those with hepatocellular carcinoma with or without inflammation. These results suggest that the factors which induce hepatocyte transformation might also trigger FasL expression and promote FasL/Fas-mediated apoptosis.

The correlation of Ureaplasma urealyticum infection with infertility

A prevalence study of Ureaplasma urealyticum (UU) infection of the male genital tract was carried out in Shanghai between March 1992 and June 1995. Significantly higher frequency of UU infection was found among infertile males (549/1416) as compared to fertile controls (34/375). Examination of 8 specimens each from infertile men and fertile subjects by electron microscopy, immunogold and immunofluorescence techniques, demonstrated adhesion of Ureaplasma urealyticum to the membrane of spermatozoa and exfoliated germ cells. In addition, gold particles on Ureaplasma urealyticum were found to be adhered to the sperm surface in 4 of the 8 samples. Strong specific anti-UU fluorescence was detected in 6 of 8 samples, mainly on the midpieces and post-acrosomal regions of the spermatozoa. To further study the effects of Ureaplasma urealyticum on fertility, 47 male Sprague-Dawley (SD) rats were infected artificially with Ureaplasma urealyticum serotype 8 (T960). Morphological changes in the seminiferous tubules were observed 3-5 weeks after inoculation in the sacrificed animals. Dramatic impairment of spermatogenesis of both testes was found in 11 rats. Mating experiment confirmed infertility in 12 of 40 rats. Offsprings of the infected rats were significantly smaller than those of controls in terms of prenatal weights and birthweights.

Matrix-assisted laser desorption/ionization for sequencing single-stranded and double-stranded DNA

The DNA sequence of a single-stranded and double-stranded template was determined. The templates were sequenced using the chain termination method and cycle sequencing method and detected by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The sequencing products were analyzed successfully without the laborious and expensive methods for removal of the template. Direct sequencing of the double-stranded template was achieved with minimal post-reaction purifications, which could be extremely important for mutation analysis and clinical diagnosis. A systematic study of the mechanisms and kinetics of sequencing reactions was also performed. The details of this analysis and directions for future improvements of the quality of sequencing are presented.

Laser desorption mass spectrometry for point mutation detection

A point mutation can be associated with the pathogenesis of inherited or acquired diseases. Laser desorption mass spectrometry coupled with allele specific polymerase chain reaction (PCR) was first used for point mutation detection. G551D is one of several mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene present in 1-3% of the mutant CFTR alleles in most European populations. In this work, two different approaches were pursued to detect G551D point mutation in the cystic fibrosis gene. The strategy is to amplify the desired region of DNA template by PCR using two primers that overlap one base at the site of the point mutation and which vary in size. If the two primers based on the normal sequence match the target DNA sequence, a normal PCR product will be produced. However, if the alternately sized primers that match the mutant sequence recognize the target DNA, an abnormal PCR product will be produced. Thus, the mass spectrometer can be used to identify patients that are homozygous normal, heterozygous for a mutation or homozygous abnormal at a mutation site. Another approach to identify similar mutations is the use of sequence specific restriction enzymes which respond to changes in the DNA sequence. Mass spectrometry is used to detect the length of the restriction fragments generated by digestion of a PCR generated target fragment.

The study of 2,3,4-trihydroxyacetophenone and 2,4,6-trihydroxyacetophenone as matrices for DNA detection in matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometric study of DNA detection using 2,3,4-trihydroxyacetophenone, 2,4,6-trihydroxyacetophenone, and their combination has been carried out systematically. The results show that a mixture of 2,4,6-trihydroxyacetophenone, 2,3,4-trihydroxyacetophenone and ammonium citrate with molar ratios of 2:1:1 serves as a good matrix for the detection of DNA, especially for samples containing a small quantity of DNA such as polymerase chain reaction product. The resolution and shot-to-shot reproducibility using this matrix are better than, and the MALDI sensitivity comparable to, that obtained when using 3-hydroxy picotinic acid (3-HPA), PA and ammonium citrate matrix (9:1:1). The mechanism of desorption/ionization using this matrix is discussed.

Urethane-protected alpha-amino acid N-carboxyanhydrides and peptide synthesis

The preparation, physical properties and analytical data are reported for seventy urethane-protected (Boc, Cbz, FMOC) amino acid N-carboxyanhydrides (UNCAs). Most of the UNCAs are crystalline and the X-ray diffraction patterns for several of these are described. UNCAs are stable to routine laboratory manipulations and can be stored for extended periods of time (1-2 years at below 0 degrees C). Most are completely stable to the conditions commonly employed for peptide synthesis. The correct choice of base is key for the successful introduction of urethane protecting groups into NCAs. N-Methylmorpholine is used for the introduction of FMOC, Cbz or Boc from the chloroformates, and pyridine is used for the introduction of the Boc group from Boc anhydride. UNCAs represent a unique class of preactivated, isolable and stable amino acid derivatives that generate no side products or co-products, other than CO2, during condensation reactions. The application of UNCAs in peptide synthesis in both solid phase and in solution is reviewed in detail.

Sweet and bitter taste: structure and conformations of two aspartame dipeptide analogues

The synthesis and X-ray diffraction analysis of two dipeptide taste ligands have been carried out as part of our study of the molecular basis of taste. The compounds L-aspartyl-D-alpha-methylphenylalanine methyl ester [L-Asp-D-(alpha Me)Phe-OMe] and L-aspartyl-D-alanyl-2,2,5, 5-tetramethylcyclopentanyl ester [L-Asp-D-Ala-OTMCP] elicit bitter and sweet taste, respectively. The C-terminal residues of the two analogues adopt distinctly different conformations in the solid state. The aspartyl moiety assumes the same conformation found in other dipeptide taste ligands with the side-chain carboxylate and the amino groups forming a zwitterionic ring with a conformation defined by psi, chi 1 = 157.7 degrees, -61.5 degrees for L-Asp-D-Ala-OTMCP and 151.0 degrees, -68.8 degrees for L-Asp-D-(alpha Me)Phe-OMe. In the second residue, a left-handed helical conformation is observed for the (alpha Me)Phe residue of L-Asp-D-(alpha Me)Phe-OMe with phi 2 = 49.0 degrees and psi 2 = 47.9 degrees, while the Ala residue of L-Asp-D-Ala-OTMCP adopts a semi-extended conformation characterized by dihedral angles phi 2 = 62.8 degrees and psi 2 = -139.9 degrees. The solid-state structure of the bitter L-Asp-D-(alpha Me)Phe-OMe is extended: while the crystal structure of the sweet L-Asp-D-OTMCP roughly adopts the typical L-shaped structure shown by other sweeteners. The data of L-Asp-D-(alpha Me)Phe-OMe are compared with those of its diastereoisomer L-Asp-L-(alpha Me)Phe-OMe. Conformational analysis of the two taste ligands in solution by NMR and computer simulations agrees well with our model for sweet and bitter tastes.

Revisit of MALDI for small proteins

Matrix-assisted laser desorption/ionization (MALDI) was used for several small proteins (such as insulin) and for peptides. It was found that the detection efficiencies of MALDI for the insulin B chain and the insulin A chain are drastically different. Similar phenomena were also observed for various types of peptides. The positive-ion signal of MALDI in detecting proteins or peptides was found to be greatly enhanced by the presence of a basic amino acid in their chains. The experimental results indicate that this enhancement may arise from proton transfer in solution by an acid-base reaction between the protein/peptide and matrix molecule. This pre-protonated mechanism provides a low energy barrier for the ionization of peptides in a MALDI process, and greatly reduces the energy threshold of MALDI. Matrix effects on the ionization mechanism are discussed.

A second regulatory gene, blaR1, encoding a potential penicillin-binding protein required for induction of beta-lactamase in Bacillus licheniformis

A second regulatory locus (blaR1) required for the induction of beta-lactamase synthesis in Bacillus licheniformis 749 was cloned and sequenced. The gene was located on a 5.2-kilobase-pair SphI DNA fragment which also contained the beta-lactamase (blaP) and repressor (blaI) genes. Bacillus subtilis BD224 carrying these three genes synthesized beta-lactamase on exposure to cephalosporin C, whereas Escherichia coli HB101 carrying the genes did not show any detectable induction of the enzyme. An open reading frame of 1,803 bases was identified as the blaR1 gene by subcloning and DNA sequencing. The gene started 2 bases downstream of the termination codon of bla1 and was preceded by a putative Shine-Dalgarno sequence (AAGGA) with a spacing of 5 bases. The deduced blaR1 product (601 amino acids) had a molecular weight of 68,425. Five transmembrane regions were predicted from the hydrophobicity profile. The region around Phe-Ala-Pro-Ala-Ser-Thr-Tyr-Lys (amino acids 398 to 405), which appeared to be located outside the membrane, was homologous to the binding regions of penicillin-binding proteins, including the beta-lactamases. The segment of 22 amino acids from 400 to 421 showed more than 70% homology to the penicillin-binding region of PBP 2 of E. coli. The blaR1 gene encodes a potential penicillin receptor which is required for the induction of beta-lactamase in B. licheniformis 749.