[Association between depression tendency and cognitive trajectory in the elderly in rural area in China]

Objective: To explore cognitive trajectory and its association with depression tendency in the elderly in rural area in China. Methods: Based on the data of the rural elderly aged ≥65 years in the Chinese Longitudinal Healthy Longevity Survey (CLHLS) from 2011 to 2018, unconditional and conditional latent variable growth curve models were constructed to analyze the mini-mental state examination (MMSE) score trajectory and its association with depression tendency in the elderly. Results: A total of 1 788 elderly persons were included, and 19.1% of them had a depression tendency. The average MMSE score of those with and without a depression tendency at baseline survey were 26.62±3.54 and 27.59±3.17 respectively. The rate of MMSE score decline was 0.52 points (P<0.05). Before and after controlling covariates, the initial score was 0.84 points lower (P<0.05) and 0.81 points lower (P<0.05) in those with depressive tendency than in those without depressive tendency respectively, furthermore, the decline rate of MMSE score was 0.33 points lower (P<0.05) and 0.40 points lower (P<0.05) in those with depressive tendency than in those without respectively. Conclusions: The depression tendency in the elderly in rural area in China was associated with the cognitive function change trajectory, with those with depression tendency had lower-level trajectory. Attention should be paid to the mental health of the elderly in rural area to prevent dementia and slow its development.

[Differences of water barrier function between keloid and its surrounding normal skin in patients with keloids and its related mechanism]

Objective: To compare the differences of water barrier function between keloids and its surrounding normal skin in patients with keloids, and to explore the primary mechanism. Methods: A cross-sectional observational study was conducted. From October 2020 to March 2021, 30 patients with keloids who met the inclusion criteria visited Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, including 18 females and 12 males, aged 20-48 years. The transepidermal water loss (TEWL) of their keloids and the surrounding normal skin of the 30 patients were measured by multi probe adapter on the reception day. The keloid tissues and normal skin of 5 patients after keloid repair surgery were processed for hematoxylin-eosin staining to measure the thickness of epidermis. Immunohistochemistry was performed on samples from 3 of those 5 patients to detect the expressions of cytokeratin-10, involucrin, and filaggrin in keloids and normal skin. Data were statistically analyzed with paired sample t test and independent sample t test. Results: On the reception day, the TEWL of keloids of 30 patients was 9.0 (6.9, 13.4) g·m-2·h-1 and the TEWL of the normal skin was 8.1 (6.4, 18.1) g·m-2·h-1, between which the difference was not statistically significant (t=0.44, P>0.05). After keloid repair surgery, the thickness of epidermis in the keloids of 5 patients was (194±44) μm, which was significantly thicker than that of the normal skin (44±11) μm, (t=6.88, P<0.01). Furthermore, increased keratinocytes, lack of normal epidermal ridge structures, and thickened stratum corneum were observed in the keloid area. After keloid repair surgery, the expression level of cytokeratin-10 in keloids was significantly lower than that in normal skin of 3 patients (t=8.50, P<0.01), but there were no statistically significant differences in the expression levels of involucrin or filaggrin between keloids and normal skin (with t values of 0.07 and 0.96, respectively, P>0.05). Conclusions: Keloid tissue from patients with keloids displays increased number of keratinocytes and thickened epidermis. But the water barrier function in keloid area is similar to the surrounding normal skin, suggesting that TEWL may not be the main mechanism lead to the persistent development of keloids.

[Comprehensive measurement and quantification of bio-mechanical properties of the temporomandibular joint disc]

Objective: To comprehensively investigate the biomechanical properties of the temporomandibular joint (TMJ) disc and to perfect the mechanical testing system of the TMJ disc by conducting tests of compression, tension, cyclic compression, cyclic tension, creep and friction. Methods: Fifteen fresh goat heads (weighing 2.5-3.0 kg) were purchased from the market. They were all ordinary goats (9-12 months old, body weighing 18-21 kg) regardless of gender. Bilateral articular discs (a total of 30) were dissected within 30 minutes after execution. According to the national standard for mechanical testing of viscoelastic materials, fresh TMJ disc specimens of goat were prepared and tests were carried out in physiological conditions. The universal mechanical testing machine was utilized to test biomechanical properties of TMJ discs. Results: The compressive modulus of TMJ discs was (8.41±2.12) MPa and the tensile modulus was (9.54±3.26) MPa. The mechanical characteristics would be irreversibly altered once the load exceeded the physiological range. In addition, it underwent apparent creep relaxation under continuous strain (0.5 MPa or 3.0 MPa) and the surface friction coefficient of the TMJ discs (0.015+0.011) was much lower than that of general viscoelastic materials. Conclusions: The TMJ disc was a bio-viscoelastic structure with excellent tensile and compressive properties and its surface was extremely smooth in wet conditions.

[Role of histone demethylase KDM6B in HBx-mediated podocyte-macrophage transdifferentiation]

Objective: To explore the expression of lysine (k)-specific demethylase 6B (KDM6B) in the renal tissues of hepatitis B virus-associated glomerulonephritis (HBV-GN) patients and human podocytes transfected with hepatitis B virus X (HBx) gene, and its role in HBx-mediated podocyte-macrophage transdifferentiation (PMT). Methods: Forty-eight patients diagnosed as HBV-GN by renal biopsy from 2013 to 2018 at the Shanghai Jiaotong University Affiliated First People's Hospital were included in this study. Thirty patients with primary glomerulonephritis (PGN) and fifteen patients with renal tumor were chosen as control group. The expression of KDM6B and macrophage marker F4/80 in renal tissues of HBV-GN patients was observed by immunofluorescence and immunohistochemistry. The association between kidney KDM6B levels and clinical features of HBV-GN patients was analyzed. The expression of KDM6B, F4/80, major histocompatibility complex (MHC)-Ⅱ and CD40 in the podocytes was detected by Western blotting. The contents of interferon-γ (IFN-γ) and interleukin-6 (IL-6) in the supernatant were determined by enzyme-linked immunosorbent assay (ELISA). The small interfering RNA of KDM6B (KDM6B siRNA) was used to silence the expression of KDM6B and the protein levels of KDM6B, F4/80 and tri-methylation of lysine 27 of histone H3 (H3K27me3) induced by HBx gene transfection were detected by Western blotting. Results: Renal KDM6B expression was significantly increased in HBV-GN patients compared to normal control (0.022±0.004 vs 0.006±0.002, P=0.006). There was no significant difference in the positive rate of KDM6B among different pathological types of HBV-GN (P=0.139). Moreover, co-expression of KDM6B and F4/80 could be observed in the podocytes of HBV-GN patients. Patients with estimated glomerular filtration (eGFR)<60 ml·min^-1·(1.73 m²)^-1or proteinuria ≥ 3.5 g/day had a significantly higher renal KDM6B expression compared to control groups (all P<0.05). In addition, the expression of KDM6B, F4/80, MHC-II and CD40 was significantly up-regulated in the podocytes transfected with HBx gene (all P<0.05). The content of IFN-γ and IL-6 in the supernatant was significantly increased (all P<0.05). After gene silencing of KDM6B, the expression of F4/80 induced by HBx in the podocytes was significantly down-regulated, while the level of H3K27me3 was significantly increased (both P<0.05). Conclusions: HBx could induce KDM6B expression in podocytes and initiate PMT, thereby involving in the dysfunction of immune microenviroment in the renal tissues of HBV-GN.

Effect of alfalfa hay and starter feed supplementation on caecal microbiota and fermentation, growth, and health of yak calves

The caecum is the primary site where microbial fermentation and acidosis occurred. The supplementation of starter feed and alfalfa hay has the potential to influence caecal microbiota and then affect caecal fermentation. This study aims to investigate the effect of starter feed and alfalfa hay supplementation on caecal microbiota, immune homeostasis, and growth of preweaning yaks. Twenty 30-day-old male yak calves were randomly assigned to four groups, which separately fed with milk replacer (CON group), milk replacer with alfalfa hay (A group), milk replacer with starter feed (S group), and milk replacer with starter feed plus alfalfa hay (SA group) throughout the trial. Growth performance and plasma physiological and biochemical indicators were measured every 30 days. Calves were sacrificed at 120 days of age. The caecal contents were collected for measuring pH and contents of volatile fatty acids (VFAs) and lipopolysaccharide (LPS) and for characterizing caecal microbiota. The results indicated that individual or simultaneous supplementation with alfalfa hay and starter feed all significantly increased the BW, body height, body length, and chest girth of yak calves. However, supplementation with starter feed significantly increased plasma cortisol, nitric oxide, tumor necrosis factor-α, and interferon-γ concentrations and the ratio of aspartate aminotransferase to alanine aminotransferase of yak calves when compared with the control and alfalfa hay feeding groups, while the co-supplementation of starter feed and alfalfa hay could significantly decrease these inflammation-related indices when compared with the starter feeding group. Sequencing of the 16S rRNA gene showed that starter feed and alfalfa hay separately stimulated the proliferation of starch-decomposing and cellulose- or hemicellulose-decomposing bacteria. This also significantly increased the levels of acetate, propionate, butyrate, valerate, isobutyrate, and isovalerate in the caecal contents. Furthermore, compared with the S and CON groups, the significantly increased genera of Desulfobulbus, Olsenella, Pseudoflavonifractor, and Stomatobaculum in the SA and A groups were beneficial to the immune homeostasis, and the significantly decreased Blautia, Clostridium IV, Bacteroides, Eubacterium, Clostridium XVIII, and Mogibacterium in the SA and A groups were related to the reduced caecal lactate and LPS contents, the decreased inflammatory reaction, and the improved healthy hepatic condition of yak calves. In conclusion, milk replacer supplemented with alfalfa hay and starter feed is recommended during preweaning to improve yak calf health and growth because this regimen promotes the growth and maintains the immune homeostasis of yak calves.

[Research value of 50 MHz high-frequency ultrasound on sonography of normal facial skin in adult]

Objective: To observe the differences in normal facial skin thickness and echo density by different ages and sites of healthy adults of the same sex using 50 MHz high-frequency ultrasound. Methods: From January to June 2019, 200 healthy adult volunteers with normal facial skin who were from Sichuan, Yunnan, Guizhou, and Chongqing and met the inclusion criteria were recruited by the Affiliated Hospital of Southwest Medical University with simple random sampling method, and then were included in this cross-sectional investigation study. Then 50 MHz high-frequency ultrasound was used to obtain skin ultrasonogram of volunteers' forehead, canthus, eyelid, and cheek. According to the ages, 100 female volunteers were divided into 20-29 years old (30 females), 30-39 years old (25 females), 40-49 years old (20 females), and 50-70 years old (25 females) groups; 100 male volunteers were divided into 20-29 years old (30 males), 30-39 years old (25 males), 40-49 years old (20 males), and 50-70 years old (25 males) groups. The thickness of full-skin, the upper dermal echo density, and the lower dermal echo density of the female and male volunteers'forehead, canthus, eyelid, and cheek were recorded respectively. Data were statistically analyzed with one-way analysis of variance, analysis of variance for repeated measurement, least significant difference test, and Bonferroni correction. Results: (1) The thickness of full-thickness skin in forehead, canthus, eyelid, and cheek of female and male volunteers in 20-29 years old group were (1.86±0.26), (1.36±0.11), (1.24±0.25), and (1.90±0.21) mm, (2.45±0.37), (1.64±0.19), (1.44±0.16), and (2.53±0.26) mm, respectively, in 30-39 years old group were (1.98±0.24), (1.43±0.13), (1.15±0.15), and (2.12±0.13) mm, (2.34±0.27), (1.63±0.27), (1.50±0.38), and (2.43±0.40) mm, respectively, in 40-49 years old group were (1.90±0.21), (1.43±0.18), (1.24±0.27), and (1.98±0.12) mm, (2.14±0.24), (1.54±0.25), (1.28±0.14), and (2.39±0.36) mm, respectively, in 50-70 years old group were (1.64±0.25), (1.36±0.19), (1.16±0.12), and (1.89±0.29) mm, (2.28±0.27), (1.73±0.25), (1.58±0.18), and (2.38±0.32) mm, respectively. There were no statistically significant differences between female volunteers in the 4 groups and male volunteers in the 4 groups in thickness of full-thickness skin in canthus, eyelid, and cheek (F=0.677, 0.666, 0.136, 0.697, 0.294, 0.888, P>0.05). The thickness of full-thickness skin in forehead and cheek of the female volunteers in the 4 groups and male volunteers in the 4 groups was similar (P>0.05), and was significantly higher than that of canthus and eyelid (P<0.05). The thickness of full-thickness skin in canthus and eyelid of female volunteers in 20-29 years old, 40-49 years old, and 50-70 years old group was similar (P>0.05), while thickness of full-thickness skin in canthus and eyelid of male volunteers in the 4 groups was similar (P>0.05). (2) The upper dermal echo density of forehead, canthus, eyelid, and cheek of female volunteers in 50-70 years old group was significantly lower than that in 20-29 years old and 30-39 years old groups (P<0.05). The upper dermal echo density of forehead, canthus, eyelid, and cheek of male volunteers in 50-70 years old group was significantly lower than that in 20-29 years old group (P<0.05). The upper dermal echo density of forehead, canthus, eyelid, and cheek of female and male volunteers in 20-29 years old and 30-39 years old groups was similar (P>0.05). The upper dermal echo density of forehead and cheek of female volunteers in 20-29 years old, 40-49 years old, and 50-70 years old groups was significantly lower than that of canthus and eyelid (P<0.05). The echo density of upper dermis of cheek of male volunteers in the 4 groups was significantly lower than that of canthus and eyelid (P<0.05). The upper dermal echo density of canthus and eyelid of female volunteers in the 4 groups and male volunteers in the 4 groups was similar (P>0.05), the upper dermal echo density of forehead and cheek was similar (P>0.05). (3) The lower dermal echo density of forehead, canthus, eyelid, and cheek of female volunteers in 50-70 years old group was significantly higher than that in 20-29 years old and 30-39 years old groups (P<0.05). The lower dermal echo density of forehead, canthus, eyelid, and cheek of male volunteers in 50-70 years old group was significantly higher than that in 20-29 years old group (P<0.05). The echo density of the lower dermis of forehead, eyelid, and cheek of female and male volunteers in 20-29 years old, 30-39 years old, and 40-49 years old groups was similar (P>0.05). The lower dermal echo density of forehead and cheek of female volunteers in the 4 groups was significantly lower than that of canthus and eyelid (P<0.05). The lower dermal echo density of forehead and cheek of male volunteers in 30-39 years old, 40-49 years old, and 50-70 years old groups was significantly lower than that of canthus and eyelid (P<0.05). The lower dermal echo density between canthus and eyelid and between forehead and check of female volunteers in the 4 groups and male volunteers in the 4 groups was similar (P>0.05). Conclusions: The 50 MHz high-frequency ultrasonography shows that the thickness of full-thickness skin of canthus, eyelid, and cheek is similar in all age groups of female and male adult volunteers with normal facial skin. In the same age group, the thickness of full-thickness skin of forehead and cheek of male and female volunteers is significantly higher than that of canthus and eyelid. The upper dermal echo density of forehead, canthus, eyelid, and cheek of female and male volunteers shows a decreasing trend with age, while the lower dermal echo density shows an increasing trend with age. In addition, the echo density of upper and lower dermis of canthus and eyelid was significantly higher than that of cheek in all the four age groups.

[Clinical effectiveness of super pulsed carbon dioxide fractional laser debridement surgery in treating chronic wounds]

Objective: To investigate the clinical effectiveness of super pulsed carbon dioxide fractional laser debridement surgery on the treatment of chronic wounds. Methods: From December 2018 to May 2019, 37 patients with chronic wounds who met the inclusion criteria were admitted to the Affiliated Hospital of Southwest Medical University for a prospective randomized controlled study. Using the random number table, the patients were divided into surgical debridement group (19 patients, 4 males and 15 females, aged (58±16) years, 25 wounds) and laser debridement group (18 patients, 9 males and 9 females, aged (58±10) years, 23 wounds). In patients of surgical debridement group, oedematous and aging granulation tissue was scraped from the wound by scalpel handle or curet, and the residual necrotic tissue was removed by sharp surgical instruments. In patients of laser debridement group, oedematous and aging granulation tissue and necrotic tissue was removed by super pulsed carbon dioxide fractional laser therapeutic machine, laser gasification debridement was performed repeatedly till fresh normal tissue layer observed. In patients of the two groups, according to the wound in the first 3 d after the first debridement, debridement dressing was performed twice at least as before, then wound debridement dressing was performed once every 1 to 4 days as before according to the wound conditions. The wound healing rates on 7, 14, 21, and 28 d after the first debridement were calculated. The positive rates of bacterial culture of wounds before and after the first debridement were calculated. The color and texture of the wound granulation tissue before the first debridement and on 7, 14, and 28 d after the first debridement were observed and scored. The pain scores before every debridement, during every debridement, and after every debridement dressing change were evaluated by visual analogue scale. The times of debridement dressing change were recorded. Data were statistically analyzed with two independent sample t test, analysis of variance for repeated measurement, Fisher's exact probability test, Mann-Whitney U test, and Bonferroni correction. Results: (1) On 7, 14, 21, and 28 d after the first debridement, the wound healing rates of patients in laser debridement group (29.5% (24.1%, 36.0%), 47.1% (42.7%, 62.4%), 71.4% (62.2%, 76.8%), and 88.6% (79.2%, 96.3%) were significantly higher than those of surgical debridement group (1.6% (1.0%, 12.8%), 12.7% (2.0%, 16.6%), 24.5% (8.9%, 45.5%), 43.9% (23.2%, 70.8%), Z=3.477, 3.553, 2.721, 2.193, P<0.05 or P<0.01). (2) Before the first debridement, the positive rates of bacterial culture of wounds in patients of laser debridement group and surgical debridement group were 92% (23/25) and 91% (21/23), respectively, which were similar (P>0.05). After the first debridement, the positive rate of bacterial culture of wounds of patients in surgical debridement group was 64% (16/25), which was significantly higher than 13% (3/23) of laser debridement group (P<0.01). (3) On 7, 14, and 28 d after the first debridement, the scores of color and texture of wound granulation tissue of patients in laser debridement group were significantly higher than those of surgical debridement group (Z=3.420, 5.682, 6.142, 4.461, 5.337, 4.458, P<0.01). (4) The pain scores during every debridement and after every debridement dressing change in patients of laser debridement group were significantly lower than those of surgical debridement group (t=2.847, 5.046, P<0.05 or P<0.01). (5) The time of debridement dressing change in laser debridement group was 8.0 (7.0, 10.0) times, which was significantly less than 10.0 (9.5, 12.5) times in surgical debridement group (Z=2.261, P<0.05). Conclusions: Compared with traditional surgical debridement method, super pulsed carbon dioxide fractional laser debridement surgery is more effective in treating patients with chronic wounds. Laser debridement makes the wound healing more efficiently with reduced pain and better infection control; significantly reduces the number of dressing changes, and is especially suitable for the wound treatment in outpatients.

Intestinal dysbacteriosis mediates the reference memory deficit induced by anaesthesia/surgery in aged mice

BACKGROUND

Postoperative cognitive dysfunction (POCD) is associated with increased morbidity and mortality and has become a major concern for patients and caregivers. POCD is most common in older patients. Previous studies demonstrated that the gut microbiome affects cognitive function and behaviour, and perioperative factors, including the operation itself, antibiotics, opioids or acid-inducing drugs, affect the gut microbiome. Thus, we hypothesised that intestinal dysbacteriosis caused by anaesthesia/surgery induces POCD.

METHODS

Tibial fracture internal fixation was performed in 18-month-old C57BL/6 mice under isoflurane anaesthesia to establish the POCD model. The Morris water maze was used to measure reference memory after anaesthesia/surgery. High-throughput sequencing of 16S rRNA from faecal samples was used to investigate changes in the abundance of intestinal bacteria after anaesthesia/surgery. To confirm the role of the gut microbiome in POCD, we pretreated mice with compound antibiotics or mixed probiotics (VSL#3). Anaesthesia/surgery impaired reference memory and induced intestinal dysbacteriosis in aged mice.

RESULTS

The 16S rRNA sequencing data revealed 37 genera (18 families) of bacteria that changed in abundance after anaesthesia/surgery. Pretreating mice with compound antibiotics or mixed probiotics (VSL#3) prevented the learning and memory deficits induced by anaesthesia/surgery. We further conducted quantitative real-time polymerase chain reaction (qRT-PCR) of 22 common types of bacteria among the 37 total types to verify the results of bacterial flora changes after anaesthesia/surgery. Numbers of 8 types of bacteria changed after anaesthesia/surgery but returned to normal after treatment with a mix of probiotics.

CONCLUSIONS

Our data suggest that deficits in reference memory induced by anaesthesia/surgery are mediated by intestinal dysbacteriosis.

[Analysis on prognosis and influencing factors of postoperative low anterior resection syndrome for rectal cancer patients undergoing laparoscopic anus-preserving radical resection]

Objective: To investigate the prognosis and influencing factors of postoperative low anterior resection syndrome (LARS) for rectal cancer patients undergoing laparoscopic sphincter-preserving radical resection. Methods: A retrospective case-control study was used in this study. Clinical data of 268 rectal cancer patients undergoing laparoscopic sphincter-preserving radical resection at Department of Gastrointestinal Surgery of The First Affiliated Hospital of Bengbu Medical College from January 2016 to January 2018 were retrospectively collected. Inclusion criteria: (1) operation procedure was total mesorectal excision (TME) and sphincter-preserving radical resection; (2) rectal cancer was confirmed by postoperative pathology; (3) age of patient was ≥ 18 years old. Exclusion criteria: (1) patient who had history of pelvic surgery and pelvic fractures, which would affect the anorectal function; (2) patient who had history of preoperative chronic constipation and irritable bowel syndrome, which would affect defecation; (3) patient who developed postoperative complications, such as anastomotic leakage, which would affect defecation function; (4) patient who received long-term use of drugs, which would affect the function of gastrointestinal tract or anus; (5) patient suffered from mental illness, who was unable to communicate properly; (6) patient who was lack of clinical data or had incomplete clinical data. Patients were followed up at 3, 6 and 12 months postoperatively, and LARS was diagnosed and graded according to the LARS score scale. The LARS score ranged from 0 to 42 points, and 0 to 20 was difined as no LARS, 21 to 29 was mild LARS, and 30 to 42 was severe LARS. LARS score >20 points at any time point was defined as postoperative LARS. Severe LARS transferring into mild LARS and mild LARS transferring into no LARS was defined as symptom improvement. Incidence and outcomes of LARS were evaluated. The factors associated with LARS outcomes were analyzed using χ(2) test and logistic regression model. Results: A total of 268 patients were enrolled. The incidence of LARS was 42.9% (115/268), 32.5% (87/268) and 20.1% (54/268) at 3, 6, and 12 months postoperatively respectively, and no new case of LARS was found after 3 months postoperatively. The incidence of mild LARS was 25.7% (69/268), 17.2% (46/268) and 8.6% (23/268) at 3, 6, and 12 months postoperatively respectively, and mild LARS incidence at 6 months was significantly lower than that at 3 months (χ(2)=5.857, P=0.016), and was significantly higher than that at 12 months (χ(2)=8.799, P=0.003). The incidence of severe LARS was 17.2% (46/268), 15.3% (41/268) and 11.6% (31/268) at 3, 6, and 12 months postoperatively respectively, without significant difference among 3 time points (all P>0.05). The improvement rate within one year after surgery in patients with mild LARS diagnosed at 3 months was significantly higher than that in patients with severe LARS (88.4% vs. 32.6%, χ(2)=38.340, P<0.001). Univariate analysis showed that female, distance from anastomosis to anal verge < 5 cm and tumor diameter ≥ 5 cm were associated with unsatisfied LARS outcomes (all P<0.05). Logistic regression analysis showed that distance from anastomosis to anal verge <5 cm was an independent risk factor for LARS outcome (OR=3.589, 95% CI: 1.163 to 2.198, P<0.001). Conclusions: The incidence of LARS after laparoscopic sphincter-preserving radical resection decreases with time. The improvement rate within postoperative 1-year of severe LARS is lower than that of mild LARS. Low anastomotic position may lead to impaired improvement of LARS.

[Retrospective cohort study on the correlation between high value of lactic acid and risk of death in 127 patients with extensive burn during shock stage]

Objective: To analyze the relationship between serum lactic acid value and risk of death in patients with extensive burn during shock stage and the related influencing factors. Methods: Clinical data of 127 patients (111 males and 16 females) with extensive burn admitted to Institute of Burn Research of the First Affiliated Hospital of Army Medical University from January 2009 to December 2013 and Department of Plastic Surgery and Burns of the Affiliated Hospital of Southwest Medical University from January 2016 to December 2018, who met the admission criteria, were retrospectively analyzed. The patients aged 21 to 62 years, with total burn area more than 50% total body surface area. All patients were treated with antishock therapy after admission. (1) According to the treatment outcome, the patients were divided into survival group (n=98) and death group (n=29). The gender, age, total burn area, partial-thickness burn area, full-thickness burn area, abbreviated burn severity index (ABSI), admission time after injury, number of patients with inhalation injury, number of patients with acute renal failure, and serum lactic acid values on admission and at post admission hour (PAH) 12, 24, 36, and 48 were recorded. (2) According to the optimal positive cut-off value of serum lactic acid 48 hours after admission, the patients were divided into high lactic acid group and normal lactic acid group. Age, gender, total burn area, indexes at PAH 48 including urea nitrogen, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), total serum bilirubin, alkaline phosphatase (ALP), albumin, white blood cell count, platelet count, lymphocyte count, prothrombin time (PT), hematocrit value, oxygenation index, respiratory index (RI), the alveolar-arterial oxygen partial pressure difference, mean arterial pressure (MAP) at PAH 48, the average urine volume within 48 hours after admission, the total volume of intravenous fluid infusion within 48 hours after admission, the volume of fluid infusion per kilogram of body mass within the first 24 hours after admission, the volume of fluid infusion per one percent of body surface area per kilogram of body mass within the first 24 hours after admission, the volume of urine per kilogram of body mass per hour within the first 24 hours after admission, and the percentage of hospital death were recorded. Data were processed with t test, chi-square test, and Fisher's exact probability test. Cox regression analysis was used to screen independent risk factors affecting the prognosis of patients. Receiver operating characteristic curve (ROC) of serum lactic acid value at PAH 48 of 127 patients was drawn to predict patients' death and determine the optimal positive cut-off value. Multivariate logistic regression analysis was used to screen independent risk factors causing increase of serum lactic acid. Results: (1) There were significantly statistical differences in total burn area, full-thickness burn area, and ABSI of patients between survival group and death group (t=6.257, 4.476, 5.727, P<0.01), while other indexes between the two groups were close. (2) The serum values of lactic acid of patients in death group on admission and at PAH 12, 24, 36, and 48 were (4.00±0.28), (4.50±0.26), (4.02±0.31), (3.48±0.22), (3.40±0.19) mmol/L, respectively, which were significantly higher than those in survival group [(3.30±0.21), (3.20±0.19), (2.33±0.17), (1.85±0.18), (1.50±0.09) mmol/L, t=14.552, 29.603, 38.133, 40.648, 74.973, P<0.05 or P<0.01]. (3) Cox regression analysis showed that the serum value of lactic acid at PAH 48 was the independent risk factor affecting the prognosis of patients, with risk ratio of 1.853 and 95% confidence interval of 1.342-2.559, P<0.01. (4) The total area under ROC of serum value of lactic acid at PAH 48 to predict death of 127 patients was 0.811, with 95% confidence interval of 0.699-0.924, P<0.01. The optimal positive cut-off value of serum value of lactic acid was 1.75 mmol/L, with sensitivity of 75.0% and specificity of 79.5% for predicting death. (5) There were significantly statistical differences in total burn area, ALT, AST, ALP, PT, total serum bilirubin, total volume of intravenous fluid infusion within 48 hours after admission, volume of fluid infusion per kilogram of body mass within the first 24 hours after admission, and percentage of hospital deaths of patients between high lactic acid group (n=34) and normal lactic acid group (n=93), t=3.592, 6.797, 10.367, 2.089, 2.880, 4.517, 2.984, 4.044, χ(2)=58.498, P<0.05 or P<0.01, while other indexes were close between the two groups. (6) Multivariate logistic regression analysis showed that AST and total serum bilirubin were independent risk factors for increase of serum lactic acid, with odds ratios of 1.021 and 1.064 and 95% confidence intervals of 1.001-1.040 and 1.001-1.132, P<0.05. Conclusions: Serum value of lactic acid at PAH 48 can independently predict the death of patients with extensive burns. Liver injury is an important risk factor causing hyperlacticemia during burn shock stage. Widespread increase of vascular permeability and large amount of fluid resuscitation are the core factors leading to aggravation of abdominal organ injury.

[Evaluation of bioceramic putty repairment in primary molars pulpotomy]

OBJECTIVE

To evaluate the clinical characteristics and effectiveness of bioceramic putty repairment (iroot BP Plus) used as pulp capping agents on pulpotomy in primary molars.

METHODS

Forty primary molars were treated by pulpotomy with bioceramic putty repairmen as the pulp capping agents at the Third Clinical Division of Peking University School and Hospital of Stomatology, from September 2016 to September 2017. The children who were followed up over one year were selected as the subjects of this study. The teeth were checked clinically and radiographically during fixed intervals, and classified into one of five outcomes: N, H, P₀, P_X, P_Y. N, absence of clinical symptoms, and absence of apical radiolucency; H, absence of clinical symptoms, and nonpathologic radiographic change present; P₀, absence of clinical symptoms, and pathologic change present, no need for treatment; P_X, present or absence of clinical symptoms, pathologic change present treatment or extract immediately; P_Y, premature loss of deciduous tooth. Molars classified into N and H were regarded as successful, classified into P₀, P_X and P_Y were regarded as failed.

RESULTS

Followed up for 12-24 months (the average follow up time was 16months), thirty four children were finally included, aged from 3.1 years to 8.5 yaers (the average age was 4.3 years), forty primary molars were included. Thirty four primary molars were included into N group, with absence of clinical symptoms, absence of apical radiolucency. Two molars were included into H group with physiological root absorption. One molar was included into P₀group with absence of clinical symptoms butinternal absorption of the root. Three molars were included into P_X group, with gingival fistula and apical radiolucency. None was included into P_Y group. Thirty six teeth got successful treatment, four molars failed. One year success rate of pulpotomy of primary molars using bioceramic putty repairment was 95%.

CONCLUSION

Current evidence suggests that bioceramic putty repairment as a pulpotomy medicament showed satisfied clinical and radiographic result in pulpotomy of primary molars. Bioceramic putty repairment is an acceptable material when used in pulpotomy of primary molars.

IGFBP2 promotes vasculogenic mimicry formation via regulating CD144 and MMP2 expression in glioma

Vasculogenic mimicry (VM) refers to the fluid-conducting channels formed by aggressive tumor cells rather than endothelial cells (EC) with elevated expression of genes associated with vascularization. VM has been considered as one of the reasons that glioblastoma becomes resistant to anti-VEGF therapy. However, the molecular basis underlying VM formation remains unclear. Here we report that the insulin-like growth factor-binding protein 2 (IGFBP2) acts as a potent factor to enhance VM formation in glioma. Evidence showed that elevated IGFBP2 expression was positively related with VM formation in patients with glioma. Enforced expression of IGFBP2 increased network formation of glioma cells in vitro by activating CD144 and MMP2 (Matrix Metalloproteinase 2). U251 cells with stable knockdown of IGFBP2 led to decreased VM formation and tumor progression in orthotopic mouse model. Mechanistically, IGFBP2 interacts with integrin α5 and β1 subunits and augments CD144 expression in a FAK/ERK pathway-dependent manner. Luciferase reporter and ChIP assay suggested that IGFBP2 activated the transcription factor SP1, which could bind to CD144 promoter. Thus, IGFBP2 acts as a stimulator of VM formation in glioma cells via enhancing CD144 and MMP2 expression.

Damage to epitaxial GaN layer on Al2O3 by 290-MeV 238U32+ ions irradiation

Micro-structural characteristics and electrical properties of an n-type GaN epilayer on Al₂O₃ irradiated by 290-MeV ²³⁸U³²⁺ ions to various fluences were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), high-resolution X-ray diffraction (HRXRD), and Raman scattering spectroscopy. AFM images show that the nano-hillocks generated, and the diameter and density of the nano-hillocks, increase obviously with increasing ion fluence, accompanied by an increase in surface roughness. SEM images display that the Al, O, and C elements appear on the GaN surface, along with a spiral-like, layered volcanic-cone structure formed at the highest-fluence irradiation. HRXRD reveals that the dislocation density increases, as the lattices gradually expand, and that Ga₂O₃ was produced with increasing ion fluence. Raman scattering spectra show that no N and Ga vacancies were produced, the free-carrier concentration decreases, while its mobility first increases and then exhibits a significant reduction with increasing ion fluence.

Crystal structure and Hirshfeld surface analysis of the anhydrous form of the nucleoside analogue entecavir

The nucleoside analogue entecavir {systematic name: 2-amino-9-[(1S,3R,4S)-4-hydroxy-3-hydroxymethyl-2-methylenecyclopentyl]-1,9-dihydro-6H-purin-6-one}, C₁₂H₁₅N₅O₃, is an antihepatitis B virus drug that has been approved in the US, EU and several countries worldwide. We report here the single-crystal structure of the anhydrous form and compare it with that of the previously reported monohydrate form [Jiang & Liu (2009). Acta Cryst. E65, o2232]. Hirshfeld surface analysis has been employed to understand and visualize the subtle packing differences between the two crystalline forms. The results show that, compared to the previously reported hydrated form, the anhydrous crystal has significantly different intermolecular interactions and packing patterns.

The Association Between Electronic Bullying and School Absenteeism Among High School Students in the United States

BACKGROUND

We examined the relationship between exposure to electronic bullying and absenteeism as a result of being afraid.

METHODS

This multivariate, multinomial regression analysis of the 2013 Youth Risk Behavior Survey data assessed the association between experiencing electronic bullying in the past year and how often students were absent in the last month due to feeling unsafe at/in transit to school. The model controlled for other predictors of school absence including demographics, physical/behavioral health, and risk factors. Missing data were multiply imputed.

RESULTS

Electronic bullying was significantly associated with absences. Controlling for model covariates, the relative risk of missing 1 day of school was 1.77 times higher, the relative risk of missing 2 to 3 days of school per month increased by a factor of 2.08, and the relative risk of missing 4 or more days of school per month increased by a factor of 1.77 for those who experienced electronic bullying in the past year compared with those who were not electronically bullied.

CONCLUSIONS

Electronic bullying's association with absenteeism places it among already recognized negative influences such as depression and binge drinking, necessitating schools to implement policies to mediate the resulting harmful effects.

MicroRNA-92b promotes hepatocellular carcinoma progression by targeting Smad7 and is mediated by long non-coding RNA XIST

MicroRNA (miRNA) and long non-coding RNA (lncRNA) have been demonstrated to participate in the progression of many cancers. Hepatocellular carcinoma (HCC) is one of the most common and aggressive malignant tumors worldwide, while the molecular mechanisms underlying HCC tumorigenesis are not completely clear. In this study, we showed that miR-92b was significantly upregulated in tumor tissue and plasma of HCC patients, and its expression level was highly correlated with gender and microvascular invasion. Functionally, miR-92b could promote cell proliferation and metastasis of HCC in vitro and in vivo. Mechanistic investigations suggested that Smad7, which exhibited an inverse relationship with miR-92b expression in HCC, was a direct target of miR-92b and could reverse its effects on HCC tumorigenesis. Furthermore, long non-coding RNA (lncRNA) X-inactive specific transcript (XIST) and miR-92b could directly interact with and repress each other, and XIST could inhibit HCC cell proliferation and metastasis by targeting miR-92b. Taken together, our study not only revealed for the first time the importance of XIST/miR-92b/Smad7 signaling axis in HCC progression but also suggested the potential value of miR-92b as a biomarker in the clinical diagnosis and treatment of HCC.

[The influence of urothelial carcinoembryonic antigen 1 on invasion and migration of oral carcinoma cell lines]

OBJECTIVE

To investigate the effects of long chain non-coding RNA urothelial carcinoembryonic antigen 1(UCA1) on invasion, migration and proliferation abilities in oral squamous cell carcinoma cell lines SCC15 and CAL27.

METHODS

Small interfering RNA of UCA1(UCA1-siRNA) was transfected into SCC15 and CAL27 cell lines by Lipofectamine(TM) 3000 to silence UCA1 , and transfected negtive control si-RNA served as a control. The effect of UCA1-siRNA was detected by quantitative real time-polymerase chain reaction(qRT-PCR) to confirm the successful inhibition of UCA1 by siRNA. The matrix metalloproteinase 9(MMP-9) protein level was detected by Western blotting analysis. The effect of siRNA on cell proliferation and invasion was assessed by transwell migration assay and wound healing assay. Cell counting kit-8(CCK-8) assay was carried out to estimate the proliferation of two cell lines with different expression levels of UCA1.

RESULTS

Expressions of UCA1 of SCC15 and CAL27 were successfully suppressed after transfected with siRNA which verified by qRT-PCR, and the efficiency of downregulation of SCC15 and CAL27 was 86.45%(P<0.001)and 78.24%(P<0.001), respectively. The migration, invasion and proliferation of SCC15 and CAL27 cell lines after transfected with siRNA were obviously restrained. The number of migration and invasion of CAL27 cells were 719.20±92.36 versus 208.00±25.58 (P=0.000 7) and 363.40 ± 45.96 versus 164.80 ± 24.68(P= 0.005 2), respectively, the number of migration and invasion of SCC15 cells were 437.20±54.75 vs 145.80±23.31(P=0.001 1) and 249.80±38.41 vs 63.80±11.11 (P=0.001 6), respectively (UCA1-si compare to negtive control), the relative proliferation rates of SCC15 and CAL27 were SCC15: R24 h=0.870, R48 h=0.863, R72 h=0.64, R96 h=0.732; CAL27: R24 h=0.913, R48 h=0.829, R72 h=0.756, R96 h= 0.705(P<0.05), and MMP-9 expression level was decreased by UCA1-siRNA compared with negative control.

CONCLUSIONS

UCA1 could enhance the ability of invasion and migration of SCC15 and CAL27 cell lines via regulating MMP-9 protein expression, which suggests that UCA1 might play a pivotal role in oral squamous cell carcinoma invasion and progression.

Assessment of genetic diversity of cucumber cultivars in China based on simple sequence repeats and fruit traits

The cucumber (Cucumis sativus L.) is an important crop grown worldwide. In this study, the genetic diversity of 42 cucumber cultivars in China was analyzed using 51 pairs of simple sequence repeat (SSR) primers. These primers identified 129 polymorphic loci, 95.6% of which were polymorphic. The mean effective number of alleles, mean Nei's gene diversity, and mean Shannon's information index were 0.36, 0.16, and 0.21, respectively. A cluster analysis demonstrated that the 42 cultivars could be divided into three groups, a result that was largely consistent with those of a principal component analysis (PCA). The PCA indicated that the three groups displayed significant variation in fruit traits. The cultivars of group 1 tended to have longer fruits (>30 cm), longer fruit ends (>4 cm), larger fruit diameters (>5 cm), a sharp strigose fruit spine, and the same fruit end shape. The basal color of the fruit in group 2 was dark green. Group 3 cultivars have no wax or mottling on the fruit surface. Our study demonstrates the value of our SSR primers for assessing genetic diversity in cucumber.

Specific alterations in plasma proteins during depressed, manic, and euthymic states of bipolar disorder

Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.

Zeptogram-scale nanomechanical mass sensing

Very high frequency (VHF) nanoelectromechanical systems (NEMS) provide unprecedented sensitivity for inertial mass sensing. We demonstrate in situ measurements in real time with mass noise floor approximately 20 zg. Our best mass resolution corresponds to approximately 7 zg, equivalent to approximately 30 xenon atoms or the mass of an individual 4 kDa molecule. Detailed analysis of the ultimate sensitivity of such devices based on these experimental results indicates that NEMS can ultimately provide inertial mass sensing of individual intact, electrically neutral macromolecules with single-Dalton (1 amu) resolution.

Leishmania mexicana: the circular DNA 1 (CD1) element contains genes encoding nucleotide-binding protein

OBJECTIVE

To determine the nucleotide sequence of cloned CD1 fragments from Leishmania mexicana and find ORFs predicted to have protein coding function.

METHODS

CD1 element was separated by CHEF and recovered by agarase, and the digested CD1 fragments were cloned into pZero vector. Nucleotide sequences were determined by the dideoxy chain termination method with the automatic sequencing system ALF using the M13 universal primers. Sequences were analyzed using GCG-PCGENE computer programs.

RESULTS

The sequence with 4,385 nucleotides was determined and two ORFs were considered to have protein coding function (encoding nucleotide-binding protein).

CONCLUSION

Genes encoding nucleotide-binding protein were identified from the amplified CD1 element of Leishmania mexicana.

Genome-wide screening for trait conferring genes using DNA microarrays

We report a DNA microarray-based method for genome-wide monitoring of competitively grown transformants to identify genes whose overexpression confers a specific cellular phenotype. Whereas transcriptional profiling identifies differentially expressed genes that are correlated with particular aspects of the cellular phenotype, this functional genomics approach determines genes that result in a specific physiology. This parallel gene-trait mapping method consists of transforming a strain with a genomic library, enriching the cell population in transformants containing the trait conferring gene(s), and finally using DNA microarrays to simultaneously isolate and identify the enriched gene inserts. Various methods of enrichment can be used; here, genes conferring low-level antibiotic resistance were identified by growth in selective media. We demonstrated the method by transforming Escherichia coli cells with a genomic E. coli library and selecting for transformants exhibiting a growth advantage in the presence of the anti-microbial agent Pine-Sol. Genes conferring Pine-Sol tolerance (19 genes) or sensitivity (27 genes) were identified by hybridizing, on DNA microarrays containing 1,160 E. coli gene probes, extra-chromosomal DNA isolated from transformed cells grown in the presence of various levels of Pine-Sol. Results were further validated by plating and sequencing of individual colonies, and also by assessing the Pine-Sol resistance of cells transformed with enriched plasmid library or individual resistance genes identified by the microarrays. Applications of this method beyond antibiotic resistance include identification of genes resulting in resistance to chemotherapeutic agents, genes yielding resistance to toxic products (recombinant proteins, chemical feedstocks) in industrial fermentations, genes providing enhanced growth in cell culture or high cell density fermentations, genes facilitating growth on unconventional substrates, and others.

Orally bioavailable, indole-based nonpeptide GnRH receptor antagonists with high potency and functional activity

Stereospecific introduction of a methyl group to the indole-3-side chain enhanced activity in our tryptamine-derived series of GnRH receptor antagonists. Further improvements were achieved by variation of the bicyclic amino moiety of the tertiary amide and by adjustment of the tether length to a pyridine or pyridone terminus. These modifications culminated in analogue 24, which had oral activity in a rat model and acceptable oral bioavailability and half-life in dogs and monkeys.

Expression of the Klebsiella pneumoniae CG21 acetoin reductase gene in Clostridium acetobutylicum ATCC 824

Acetoin reductase catalyzes the production of 2,3-butanediol from acetoin. The gene encoding the acetoin reductase of Klebsiella pneumoniae CG21 was cloned and expressed in Escherichia coli and Clostridium acetobutylicum ATCC 824. The nucleotide sequence of the gene encoding the enzyme was determined to be 768 bp long. Expression of the K. pneumoniae acetoin reductase gene in E. coli revealed that the enzyme has a molecular mass of about 31,000 Da based on sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis. The K. pneumoniae acetoin reductase gene was cloned into a clostridial/E. coli shuttle vector, and expression of the gene resulted in detectable levels of acetoin reductase activity in both E. coli and C. acetobutylicum. While acetoin, the natural substrate of acetoin reductase, is a typical product of fermentation by C. acetobutylicum, 2,3-butanediol is not. Analysis of culture supernatants by gas chromatography revealed that introduction of the K. pneumoniae acetoin reductase gene into C. acetobutylicum was not sufficient for 2,3-butanediol production even though the cultures were producing acetoin. 2,3-Butanediol was produced by cultures of C. acetobutylicum containing the gene only when commercial acetoin was added.

Up-regulation of Fas ligand expression by human cytomegalovirus immediate-early gene product 2: a novel mechanism in cytomegalovirus-induced apoptosis in human retina

Human CMV (HCMV) is an important pathogen that causes widespread diseases in immunocompromised individuals. Among the opportunistic HCMV infections, HCMV retinitis is most common in transplant recipients and AIDS patients. It often leads to blindness if left untreated. The question as to how HCMV infection causes retinal pathogenesis remains unresolved. Here, we report that viral immediate-early gene product 2 (IE2), but not IE1, up-regulates the Fas ligand (FasL) expression in HCMV-infected human retinal pigment epithelium cells. Increased secretion of FasL from virally infected cells into cultured medium was observed upon HCMV infection. The capability of such cell-free medium to induce apoptosis of Fas (CD95)-expressing Jurkat cells further implies that Fas-FasL interaction might mediate cell death in the lesion of HCMV retinitis. To support this idea, we observed augmented soluble FasL levels in vitreous from AIDS patients with HCMV retinitis as compared with that from AIDS patients without HCMV infection. In addition, by in situ hybridization and immunohistochemistry, we detected enhanced signals of FasL, the existence of viral IE Ags and apoptotic cells at the same sites in the lesion of HCMV-infected retina. These results strongly suggest that IE2 induction of FasL expression in human retina might be an important event that takes place in the early stage of infection and finally leads to visual loss in individuals affiliated with HCMV retinitis.

Spontaneous uterine perforation mimicking ectopic pregnancy as the initial presentation of placental site trophoblastic tumor

Placental site trophoblastic tumor (PSTT) is a rare form of gestational trophoblastic disease (GTD), with only 100 cases reported in the literature. Irregular vaginal bleeding has been reported to be the most common presenting symptom, however, spontaneous uterine perforation, mimicking ectopic pregnancy, as the initial presentation is extremely rare, and has not yet been reported in the Chinese literature. Herein, we report a 26-year-old female with PSTT complicating with uterine perforation that mimicked ectopic pregnancy as the initial presentation. She received wide excision of the uterine perforation margin only and now remains disease-free, 2 years after the operation. Reviewing the literature, while most cases of PSTT behave a benign fashion, some exhibit malignant behavior; surgery remains the mainstay of therapy. For patients whose disease is limited to the uterus, simple total abdominal hysterectomy is the treatment of choice. For patients with extensive or metastatic disease, cytoreductive surgery (total abdominal hysterectomy and resection of extrauterine tumor load) combined with chemotherapy should be applied. Etoposide, methotrexate, actinomycin D, cyclophosphamide, and vincristine (EMA/CO) chemotherapy appears superior to other available chemotherapeutic regimens in the treatment

Potent nonpeptide GnRH receptor antagonists derived from substituted indole-5-carboxamides and -acetamides bearing a pyridine side-chain terminus

A pyridine side-chain terminus has been incorporated into the indole-5-carboxamide and indole-5-acetamide series of GnRH antagonists. Potent activity was observed in binding and functional assays. Certain branched or cyclic tertiary amides were identified as preferred in each series. Alkylation of the side-chain secondary amine had generally unfavorable effects. Variations of the gem-dialkyl substituents in the indole-5-acetamide series were also investigated.

Substituted indole-5-carboxamides and -acetamides as potent nonpeptide GnRH receptor antagonists

The 2-aryltryptamine class of GnRH receptor antagonists has been modified to incorporate carboxamide and acetamide substituents at the indole 5-position. With either a phenol or methanesulfonamide terminus on the N-aralkyl side chain, potent binding affinity to the GnRH receptor was achieved. A functional assay for GnRH antagonism was even more sensitive to structural modification and revealed a strong preference for branched tertiary amides.

2-(3,5-Dimethylphenyl)tryptamine derivatives that bind to the GnRH receptor

A series of 2-(3,5-dimethylphenyl)tryptamine derivatives was prepared and evaluated on a rat gonadotropin releasing hormone receptor assay. Some para-substituents on the 4-phenylbutyl side chain attached to the tryptamine nitrogen led to compounds with potent GnRH receptor binding. The study has helped define structural requirements for GnRH receptor binding for the 2-aryltryptamine GnRH antagonists.

Heterocyclic derivatives of 2-(3,5-dimethylphenyl)tryptamine as GnRH receptor antagonists

A series of heterocyclic 2-(3,5-dimethylphenyl)tryptamine derivatives was prepared and evaluated on a rat gonadotropin releasing hormone receptor assay. The carbon tether length and heterocyclic ring attached to the amino group of 2-(3,5-dimethylphenyl)tryptamine were varied. Several of these derivatives were potent GnRH antagonists with the most potent compound having an IC50 of 16 nM.

The effects of feed and intracellular pyruvate levels on the redistribution of metabolic fluxes in Escherichia coli

In a previous study, an Escherichia coli strain lacking the key enzymes (acetate kinase and phosphotransacetylase, ACK-PTA) of the major acetate synthesis pathways reduced acetate accumulation. The ackA-pta mutant strain also exhibits an increased lactate synthesis rate. Metabolic flux analysis suggested that the majority of excessive carbon flux was redirected through the lactate formation pathway rather than the ethanol synthesis pathway. This result indicated that lactate dehydrogenase may be competitive at the pyruvate node. However, a 10-fold overexpression of the fermentative lactate dehydrogenase (ldhA) gene in the wild-type parent GJT001 was not able to divert carbon flux from acetate. The carbon flux through pyruvate and all its end products increases at the expense of flux through biosynthesis and succinate. Intracellular pyruvate measurements showed that strains overexpressing lactate dehydrogenase (LDH) depleted the pyruvate pool. This observation along with the observed excretion of pyruvate in the ackA-pta strain indicates the significance of intracellular pyruvate pools. In the current study, we focus on the role of the intracellular pyruvate pool in the redirection of metabolic fluxes at this important node. An increasing level of extracellular pyruvate leads to an increase in the intracellular pyruvate pool. This increase in intracellular pyruvate affects carbon flux distribution at the pyruvate node. Partitioning of the carbon flux to acetate at the expense of ethanol occurs at the acetyl-CoA node while partitioning at the pyruvate node favors lactate formation. The increased competitiveness of the lactate pathway may be due to the allosteric activation of LDH as a result of increased pyruvate levels. The interaction between the reactions catalyzed by the enzymes PFL (pyruvate formate lyase) and LDH was examined.

A potent, nonpeptidyl 1H-quinolone antagonist for the gonadotropin-releasing hormone receptor

Extensive development of the structure-activity relationships of a screening lead determined three important pharmacophores for gonadotropin-releasing hormone (GnRH) receptor antagonist activity. Incorporation of the 3,4,5-trimethylphenyl group at the 3-position, 2-(2(S)-azetidinyl)ethoxy group at the 4-position, and N-4-pyrimidinylcarboxamide at the 6-position of the quinolone core resulted in the identification of 4-(2-(azetidin-2(S)-yl)ethoxy)-7-chloro-2-oxo-3-(3,4,5-trimethylphenyl)-1,2-dihydroquinoline-6-carboxylic acid pyrimidin-4-ylamide (1) as a potent antagonist of the GnRH receptor. A 10(4)-fold increase in in vitro binding affinity is observed for the GnRH receptor as compared to the initial screening lead. Compound 1 exhibits nanomolar binding activity and functional antagonism at the human receptor and is 7-fold less active at the rhesus receptor. Intravenous administration of compound 1 to rhesus monkeys results in a significant decrease of the serum levels of downstream hormones, luteinizing hormone (79% decrease in area under the curve) and testosterone (92% decrease in area under the curve), at a dose of 3 mg/kg. Quinolone 1 is a potent nonpeptidyl antagonist for the human GnRH receptor that is efficacious for the suppression of luteinizing hormone and testosterone in primates.

SAR studies of novel 5-substituted 2-arylindoles as nonpeptidyl GnRH receptor antagonists

The discovery of the potency-enhancing effect of 5-substitutions on the novel 2-arylindoles as nonpeptidyl GnRH receptor antagonists led to the identification of several analogues with high affinities on the GnRH receptor. The syntheses and SARs of these 5-substituted-2-arylindole analogues are reported.

Initial structure-activity relationship of a novel class of nonpeptidyl GnRH receptor antagonists: 2-arylindoles

A nonpeptidyl GnRH receptor antagonist (1), with a unique 2-arylindole core, was identified through the Merck in-house screening for binding affinity on the rat GnRH receptor. SAR studies directed toward the alkoxy-ethanolamine and 2-aryl groups resulted in a simpler lead structure with improved activity. This compound 50 exhibits a 60-fold improvement in binding activity over our initial lead 1.

Quinolones as gonadotropin releasing hormone (GnRH) antagonists: simultaneous optimization of the C(3)-aryl and C(6)-substituents

A series of 3-arylquinolones was prepared and evaluated for their ability to act as gonadotropin releasing hormone (GnRH) antagonists. A variety of substitution patterns of the 3-aryl substituent are described. The 3,4,5-trimethylphenyl substituent (23h) was found to be optimal.

Effect of variation of Klebsiella pneumoniae acetolactate synthase expression on metabolic flux redistribution in Escherichia coli

Escherichia coli strains carrying the Bacillus subtilis acetolactate synthase (ALS) gene were previously shown to produce less acetate with higher ATP yields. Metabolic flux analysis was used to show that excess pyruvate was channeled into the less inhibitory product, acetoin. To further understand the role of intrinsic enzymatic properties and the effect of variations in enzyme levels in the alternation of metabolic fluxes, we constructed a chromosomal integrant of the Klebsiella pneumoniae ALS gene. The reported in vitro Michaelis-Menten constants (K(m)) for the Bacillus and the Klebsiella ALS are 13.0 mM and 8.0 mM, respectively. Furthermore, expression of the Klebsiella ALS is under the control of an inducible trp promoter system. Shake-flask experiments showed a linear induction response (the ALS activity changes from about 9 to 223 U/mg of protein when the inducer concentration [IAA] varied from 0 to 40 mg/L). Chemostat experiments showed a similar induction response. Interactions between the branched reactions catalyzed by the PFL, LDH, and the ALS enzymes at the pyruvate node were examined. The results indicate the importance of in vivo enzyme activities in the redistribution of metabolic fluxes.

Effect of glucose analog supplementation on metabolic flux distribution in anaerobic chemostat cultures of Escherichia coli

Previous work in our laboratories investigated the use of methyl alpha-glucoside (alpha-MG), a glucose analog that shares a phosphotransferase system with glucose, to modulate glucose uptake and therefore reduce acetate accumulation. The results of that study showed a significant improvement in batch culture performance and a reduction in acetate excretion without any significant effect on the growth rate in complex medium. The current study investigates the effect of supplementing the culture medium with the glucose analog alpha-MG on the metabolic fluxes of Escherichia coli under anaerobic chemostat conditions at two different dilution rates. Anaerobic chemostat studies utilizing complex media supplemented with glucose or glucose and alpha-MG at dilution rates of 0.1 and 0.4 h(-1), were performed, and the metabolic fluxes were analyzed. It was found that the addition of the glucose analog alpha-MG has an effect on the specific production rate of various extracellular metabolites. This effect is slightly greater at the higher dilution rate of 0.4 h(-1). However, the glucose analog does not cause any major shift in the central metabolic patterns. It was further observed that alpha-MG supplementation does not result in the reduction in specific acetate synthesis rate in anaerobic chemostat cultures. These results emphasize the importance of testing different strategies for metabolic manipulation under the actual operating conditions.

Potent antagonists of gonadotropin releasing hormone receptors derived from quinolone-6-carboxamides

SAR studies which focused upon the C-6 position of a recently described series of quinolone gonadotropin releasing hormone antagonists are reported. Synthetic access to diverse quinolone-6-carboxamides was achieved via the palladium-catalyzed amino-carbonylation reactions of iodide 4 with various amines. Amides related to 9y were especially potent, functional antagonists of rat and human GnRH receptors.

[Sample preconcentration technique in capillary electrophoresis]

The methods of improving the detection sensitivity in analysis of trace level components by sample preconcentration technique including sample stacking, field-amplified sample injection, isotachophoresis etc. are reviewed, and 67 references are cited.

An Sp1 binding site involves the transcription of the Fas ligand gene induced by PMA and ionomycin in Jurkat cells

The transcriptional regulation of the Fas ligand (FasL) gene in Jurkat cells was investigated. We demonstrated that an Sp1 binding site, located between -280 and -275 bp relative to the translational start site (+1) of the FasL gene, was important for the transcription of the FasL gene by deletion and mutation analysis in Jurkat cells after phorbol 12-myristate 13-acetate (PMA) and ionomycin treatment. Nuclear extract of Jurkat cells formed complexes with the oligonucleotides bearing the Sp1 site within -280 to -275 of the FasL promoter. Apart from the constitutive complexes, a new complex was observed after PMA and ionomycin stimulation. Plasmid containing the Sp1 site sequence with site-directed mutation reduced the FasL promoter activity in driving the expression of reporter luciferase gene expression in transfected Jurkat cells after PMA and ionomycin stimulation. The binding of activated Jurkat cell nuclear extract to the mutated Sp1 binding site of the FasL promoter was ablated. In addition, the oligomer containing the Sp1 site of the FasL promoter could compete with oligomer with conserved Sp1 binding sequence in nuclear protein binding of activated Jurkat cells. The data presented in this study suggest that the transactivation of the FasL promoter via the Sp1 binding sequence (-280 to -275) involves the PMA- and ionomycin-induced expression of the FasL gene.

[Separation and determination of nycodenz and its impurities by capillary electrophoresis]

Separation and determination of nycodenz (a new radiography reagent) and its impurities by capillary electrophoresis was investigated. Since the analytes were polyols, Na2B4O7-H3BO3 was chosen as the buffer system. The analytes were negatively charged by complexing with borate. Then cetyltrimethylammonium bromide was used to reverse electroosmotic mobility in order to shorten the analysis time. 2-Propanol was added to optimize the separation further. Acceptable results of linearity, precision of corrected peak area and migration time were obtained. The RSD(n = 6) of corrected peak area and migration time were 0.73% and 1.4% respectively. The results obtained by CE were directly compared to those obtained by high performance liquid chromatography.

Effect of inactivation of nuo and ackA-pta on redistribution of metabolic fluxes in Escherichia coli

The nuoA-N gene cluster encodes a transmembrane NADH:ubiquinone oxidoreductase (NDH-I) responsible for coupling redox chemistry to proton-motive force generation. Interactions between nuo and the acetate-producing pathway encoded by ackA-pta were investigated by examining the metabolic patterns of several mutant strains under anaerobic growth conditions. In an ackA-pta strain, the flux to acetate was decreased dramatically, whereas flux to lactate was increased significantly when compared with its parent strain; the fluxes to pyruvate and ethanol also increased slightly. In addition, pyruvate was excreted. A strain carrying the nuo mutation showed metabolic flux distribution similar to the wild type. The ackA-pta-nuo strain showed a different metabolic pattern. It not only exhibited reduced acetate accumulation but also significantly lower ethanol and formate synthesis. Metabolic flux distribution analysis suggests that the excessive carbon flux was redirected at the pyruvate node through the lactate dehydrogenase pathway for lactate formation rather than the pyruvate formate-lyase (PFL) pathway for acetyl-CoA and formate production. The diminished capacity through the formate and ethanol (ADH) pathways was not the result of genetic disruption of functional PFL or ADH production. The introduction of a Bacillus subtilis acetolactate synthase gene returned formate, ethanol, and lactate levels to those of the wild type (ackA(+)pta(+)nuo(+)) strain. Furthermore, transfer of a lactate dehydrogenase mutation yielded a strain producing ethanol as the sole fermentation product. As confirmation of the nuo effect, cultures of the ackA-pta strain, supplemented with an NDH-I inhibitor, produced intermediary levels of flux to ethanol and formate. Mutations in both ackA-pta and nuo are required to significantly reduce the flux through the PFL pathway.

Identification and initial structure-activity relationships of a novel non-peptide quinolone GnRH receptor antagonist

Screening of the Merck sample collection for non-peptide compounds with binding affinity for the rat GnRH receptor led to the identification of the substituted quinolone (1) as a lead compound in the search for a non-peptide GnRH receptor antagonist. Substantial improvements in potency (approximately 300 fold) were achieved by addition of an alkyl amine at the 4-position, a 3,5-dimethylphenyl group at the 3-position and 6-nitro-7-chloro-substitution of the 1 H-quinolone core.

Investigation of the 4-O-alkylamine substituent of non-peptide quinolone GnRH receptor antagonists

Synthesis and in vitro activity of the enantiomers of quinolone GnRH antagonist (+/-)-1 are reported. Chiral amino alcohols were prepared from the appropriate cyclic D- or L-amino acids by the Amdt-Eistert homologation followed by reduction of the resulting esters. Incorporation of these pharmacophores was achieved via a novel Mitsunobu alkylation of 4-hydroxyquinolones. The key amine pharmacophore for binding to the rat GnRH receptor was most active in the S-configuration. Ring size was not important for potency with 4, 5, 6, and 7-membered ring amines exhibiting similar potency.

Redistribution of metabolic fluxes in Escherichia coli with fermentative lactate dehydrogenase overexpression and deletion

Under anaerobic conditions, competition for pyruvate between the branch point enzymes pyruvate formate lyase (PFL, Km = 2 mM) and fermentative lactate dehydrogenase (LDH, Km = 7.2 mM) determines the partition of carbon flux. Two Escherichia coli mutant strains, one deficient in ackA, pta, and ldhA and the other overexpressing LDH, were constructed to systematically analyze the effects of these perturbations in the existing pathways on the redistribution of carbon fluxes. Deletion of the lactate and acetate synthesis pathways was detrimental to cell growth. Carbon flux is forced through ethanol and formate production pathways, resulting in a concomitant increase in those fluxes. In addition, overexpression of LDH simultaneously increases the common flux as well as the flux to the competing acetyl-CoA branch. Overexpression of lactate dehydrogenase (ldhA) in the parent strain increases the lactate synthesis rate from 0.19 to 0.40 mmol/g-biomass-h when the LDH activities increases from 1.3 to 15.3 units. Even an increase of more than 10 times in the LDH activity fails to divert a large fraction of the carbon flux to lactate; the majority of the flux still channels through the acetyl-CoA branch. Overexpression of LDH in the parent strain simultaneously increases the common flux as well as the flux through the acetyl-CoA branch. Subsequently, the flux amplification factors (or deviation indices which can be related to the flux control coefficients) are positive for all three fluxes occurring at the pyruvate node.

Metabolic flux analysis of Escherichia coli deficient in the acetate production pathway and expressing the Bacillus subtilis acetolactate synthase

Several approaches to reduce acetate accumulation in Escherichia coli cultures have recently been reported. This reduction subsequently led to a significant enhancement in recombinant protein production. In those studies, metabolically engineered E. coli strains with reduced acetate synthesis rates were constructed through the modification of glucose uptake rate, the elimination of critical enzymes that are involved in the acetate formation pathways, and the redirection of carbon flux toward less inhibitory byproducts. In particular, it has been shown that strains carrying the Bacillus subtilis acetolactate synthase (ALS) gene not only produce less acetate but also have a higher ATP yield. Metabolic flux analysis of carbon flux distribution of the central metabolic pathways and at the pyruvate branch point revealed that this strain has the ability to channel excess pyruvate to the much less toxic compound, acetoin. The main focus of this study is the systematic analysis of the effects of small perturbations in the host's existing pathways on the redistribution of carbon fluxes. Specifically, a mutant with deleted acetate kinase (ACK) and acetyl phosphotransferase (PTA) was constructed and studied. Results from the metabolic analysis of carbon redistribution show the ackA-pta mutation will reduce acetate level at the expense of the growth rate. In addition, in the ackA-pta deficient strain a much higher lactate formation rate with simultaneously lower formate and ethanol synthesis rates was found. Expression of the B. subtilis ALS in ackA-pta mutants further reduces acetate levels while cell density similar to that of the parent strain is attained.