Development and validation of a nomogram to predict postsurgical intra-abdominal infection in blunt abdominal trauma patients: A multicenter retrospective study

BACKGROUND

Intra-abdominal infection is a common complication of blunt abdominal trauma. Early detection and intervention can reduce the incidence of intra-abdominal infection and improve patients' prognoses. This study aims to construct a clinical model predicting postsurgical intra-abdominal infection after blunt abdominal trauma.

METHODS

This study is a retrospective analysis of 553 patients with blunt abdominal trauma from the Department of General Surgery of 7 medical centers (2011-2021). A 7:3 ratio was used to assign patients to the derivation and validation cohorts. Patients were divided into 2 groups based on whether intra-abdominal infection occurred after blunt abdominal trauma. Multivariate logistic regression and least absolute shrinkage and selection operator regression were used to select variables to establish a nomogram. The nomogram was evaluated, and the validity of the model was further evaluated by the validation cohort.

RESULTS

A total of 113 were diagnosed with intra-abdominal infection (20.4%). Age, prehospital time, C-reactive protein, injury severity score, operation duration, intestinal injury, neutrophils, and antibiotic use were independent risk factors for intra-abdominal infection in blunt abdominal trauma patients (P < .05). The area under the receiver operating curve (area under the curve) of derivation cohort and validation cohort was 0.852 (95% confidence interval, 0.784-0.912) and 0.814 (95% confidence interval, 0.751-0.902). The P value for the Hosmer-Lemeshow test was .135 and .891 in the 2 cohorts. The calibration curve demonstrated that the nomogram had a high consistency between prediction and practical observation. The decision curve analysis also showed that the nomogram had a better potential for clinical application. To facilitate clinical application, we have developed an online at https://nomogramcgz.shinyapps.io/IAIrisk/.

CONCLUSION

The nomogram is helpful in predicting the risk of postoperative intra-abdominal infection in patients with blunt abdominal trauma and provides guidance for clinical decision-making and treatment.

[Analysis of clinicopathological characteristics, therapeutic strategy and prognosis of 501 patients with gastric neuroendocrine neoplasms attending a single center]

Objective: To explore the clinicopathological features, treatment strategy and to analysis of prognosis-related risk factors of gastric neuroendocrine neoplasms(G-NEN). Methods: In this study, a retrospective observational study method was used to collect the clinicopathological data of patients diagnosed with G-NEN by pathological examination in the First Medical Center of PLA General Hospital from January 2000 to December 2021. The basic information of the patients, tumor pathological characteristics, and treatment methods were entered, and the treatment information and survival data after discharge were followed up and recorded. The Kaplan-Meier method was used to construct survival curves, and the log-rank test to analyze the differences in survival between groups. Cox Regression model analysis of risk factors affecting the prognosis of G-NEN patients. Results: Among the 501 cases confirmed as G-NEN, 355 were male and 146 were female, and their median age was 59 years. The cohort comprised 130 patients (25.9%) of neuroendocrine tumor (NET) G1, 54 (10.8%) of NET G2, 225 (42.9%) of neuroendocrine carcinoma (NEC), and 102 cases (20.4%) of mixed neuroendocrine-non-neuroendocrine(MiNEN). Patients NET G1 and NET G2 were mainly treated by endoscopic submucosal dissection (ESD) and endoscopic mucosal resection (EMR). The main treatment for patients with NEC/MiNEN was the same as that for gastric malignancies, namely radical gastrectomy+lymph node dissection supplemented with postoperative chemotherapy. There were significant differences in sex, age, maximum tumor diameter, tumor morphology, tumor numbers, tumor location, depth of invasion, lymph node metastasis, distant metastasis, TNM staging and expression of immunohistological markers Syn and CgA among NET, NEC, and MiNEN patients (all P<0.05). Further for NET subgroup analysis, there were significant differences between NET G1 and NET G2 in the maximum tumor diameter, tumor shape and depth of invasion(all P<0.05). 490 patients (490/501, 97.8%) were followed up with a median of 31.2 months. 163 patients had a death during follow-up (NET G1 2, NET G2 1, NEC 114, MiNEN 46). For NET G1, NET G2, NEC and MiNEN patients,the 1-year overall survival rates were 100%, 100%, 80.1% and 86.2%, respectively; the 3-year survival rates were 98.9%, 100%, 43.5% and 55.1%, respectively. The differences were statistically significant (P<0.001). Univariate analysis showed that gender, age, smoking history, alcohol history, tumor pathological grade, tumor morphology, tumor location, tumor size, lymph node metastasis, distant metastasis, and TNM stage were associated with the prognosis of G-NEN patients (all P<0.05). Multivariate analysis showed that age ≥60 years, pathological grade of NEC and MiNEN, distant metastasis, and TNM stage III-IV were independent factors influencing the survival of G-NEN patients (all P<0.05). 63 cases were stage IV at initial diagnosis. 32 of these were treated with surgery and 31 with palliative chemotherapy. Stage IV subgroup analysis showed that the 1-year survival rates were 68.1% and 46.2% in the surgical treatment and palliative chemotherapy groups, respectively, and the 3-year survival rates were 20.9% and 10.3%, respectively; the differences were statistically significant (P=0.016). Conclusions: G-NEN is a heterogeneous group of tumors. Different pathological grades of G-NEN have different clinicopathological features and prognosis. Factors such as age ≥ 60 years old, pathological grade of NEC/MiNEN, distant metastasis, stage III, IV mostly indicate poor prognosis of patients. Therefore, we should improve the ability of early diagnosis and treatment, and pay more attention to patients with advanced age and NEC/MiNEN. Although this study concluded that surgery improves the prognosis of advanced patients more than palliative chemotherapy, the value of surgical treatment for patients with stage IV G-NEN remains controversial.

[Application and progress of artificial intelligence technology in gastric cancer diagnosis and treatment]

Artificial intelligence (AI) is one of the most rapidly evolving fields in biomedicine during the past decade. Represented by radiomics, machine learning and deep neural network, AI has been increasingly favored by researchers due to its ability to obtain feature information and discover the potential relationship between data and medical outcomes from high-throughput medical data. The incidence and mortality of gastric cancer (GC) has remained high in China. Through combining AI technology with medical examination such as endoscopy, imaging, pathological examination and sequencing, clinical researchers have made great progress in the auxiliary diagnosis, disease staging, prognosis and curative effect prediction of patients with GC. Although the intervention of AI in the medical industry has greatly improved the effective utilization of high-throughput data and accelerated the intelligent process of disease diagnosis and treatment, a number of problems has been raised in medical ethics, patient privacy and the legal status of medical AI at the same time. In the future, rational planning and management of AI technology will provide a strong impetus to promote the development of medicine and reshape the medical industry.

[Preliminary experience with double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after total laparoscopic proximal gastrectomy for the treatment of adenocarcinoma of esophagogastric junction]

Objective: To explore the feasibility and preliminary technical experience of the double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after total laparoscopic proximal gastrectomy (TLPG) in the treatment of adenocarcinoma of esophagogastric junction (AEG). Methods: A descriptive case series study method was used. Clinical data of 12 AEG patients who underwent the double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after TLPG from January 2021 to June 2021 at the Department of General Surgery, First Medical Center, PLA General Hospital were retrospectively analyzed. Among the 12 patients, the median tumor diameter was 2.0 (1.5-2.9) cm, and the pathological stage was T1-3N0-3aM0. All the patients routinely underwent TLPG and D2 lymph node dissection with double-tract reconstruction combined with π-shaped esophagojejunal anastomosis: (1) Double-tract reconstruction combined with π-shaped esophagojejunal anastomosis: mesentery 25 cm away from the Trevor ligament was treated, and an incision of about 1 cm was made on the mesenteric border of the intestinal wall and the right wall of the esophagus, two arms of the linear cutting closure were inserted, and esophagojejunal side-to-side anastomosis was performed. A linear stapler was used to cut off the lower edge of the anastomosis and close the common opening to complete the esophagojejunal π-shaped anastomosis. (2) Side-to-side gastrojejunostomy anastomosis: an incision of about 1 cm was made at the jejunum to mesenteric border and at the greater curvature of the remnant stomach 15 cm from the esophagojejunostomy, and a linear stapler was inserted to complete the gastrojejunostomy side-to-side anastomosis. (3) Side-to-side jejunojejunal anastomosis: an incision of about 1 cm was made at the proximal and distal jejunum to the mesangial border 40 cm from the esophagojejunostomy, and two arms of the linear stapler were inserted respectively to complete the side-to-side jejunojejunal anastomosis. A midline incision about 4-6 cm in the upper abdomen was conducted to take out the specimen, and an abdominal drainage tube was placed, then layer-by-layer abdominal closure was performed.

INDICATIONS

(1) adenocarcinoma of esophagogastric junction (Seiwert type II-III) was diagnosed by endoscopy and pathological examination; (2) ability to preserve at least 1/2 of the distal stomach after R0 resection of proximal stomach was evaluated preoperatively.

CONTRAINDICATIONS

(1) evaluation indicated distant metastasis of tumor or invasion of other organs; (2) short abdominal esophagus or existence of diaphragmatic hiatal hernia was assessed during the operation; (3) mesentery was too short or the tension was too high; (4) existence of severe comorbidities before surgery; (5) only palliative surgery was required in preoperative evaluation; (6) poor nutritional status.

MAIN OUTCOME MEASURES

operation time, intraoperative blood loss, postoperative complications, time to first flatus and time to start liquid diet, postoperative hospital stay, operation cost, etc. Continuous variables that conformed to normal distribution were presented as mean ± standard deviation, and those that did not conform to normal distribution were presented as median (Q1,Q3). Results: All the patients successfully completed TLPG with double-tract reconstruction combined with π-shaped esophagojejunal anastomosis, and postoperative pathology showed that no cancer cells were found on the upper incision margin. The operation time was (247.9±62.4) minutes, the median intraoperative blood loss was 100.0 (62.5, 100.0) ml, no intraoperative blood transfusion was required, the incision length was (4.9±1.0) cm, and the operation cost was (55.5±0.7) thousand yuan. The median time to start liquid diet was 1.0 (1.0, 2.0) days, and the mean time to flatus was (3.1±0.9) days. All the patients were discharged uneventfully. Only 1 patient developed postoperative paralytic ileus and infectious pneumonia with Clavien-Dindo classification of grade II. The patient recovered after conservative treatment. There was no surgery-related death. The postoperative hospital stay was (8.3±2.1) days. Conclusion: The double-tract reconstruction combined with π-shaped esophagojejunal anastomosis after TLPG is safe and feasible, which can minimize surgical trauma and accelerate postoperative recovery.

[A comparative study on short-term outcomes and quality of life for gastric cancer patients between totally laparoscopic total gastrectomy using an endoscopic linear stapler and laparoscopic-assisted total gastrectomy using a circular stapler]

Objective: To explore the differences of short-term outcomes and quality of life (QoL) for gastric cancer patients between totally laparoscopic total gastrectomy using an endoscopic linear stapler and laparoscopic-assisted total gastrectomy using a circular stapler. Methods: A retrospective cohort study was conducted. Clinicopathological data of patients with stage I to III gastric adenocarcinoma who underwent laparoscopic total gastrectomy from January 2017 to January 2020 were retrospectively collected. Those who were ≥80 years old, had serious complications that could affect the quality of life, underwent multi-organ resections, palliative surgery, emergency surgery due to gastrointestinal perforation, obstruction, bleeding, died or lost to follow-up within 1 year after surgery were excluded. A total of 130 patients were enrolled and divided into circular stapler group (CS group, 77 cases) and linear stapler group (LS group, 53 cases) according to the surgical method. The differences of age, gender, body mass index, number of comorbidities, history of abdominal surgery, ASA, tumor location, degree of differentiation, tumor length, tumor T stage, tumor N stage, tumor pathological stage and preoperative quality of life between the two groups were not statistically significant (all P>0.05). The observation indicators: (1) Surgery and postoperative conditions. (2) Postoperative complications: Any adverse conditions that require conservative treatment or surgical intervention after surgery were defined as postoperative complications, of which, complications occurring within 30 days after surgery were defined as early complications; complications occurring within 30 days to 1 year after surgery were defined as late complications. (3) Postoperative quality of life was assessed by the quality of life core scale (QLQ-C30) and gastric cancer specific module scale (QLQ-STO22). The higher the scores of functional scales and global health status, the better the corresponding quality of life. The higher the scores of symptoms scales, the worse the corresponding quality of life. Results: (1) Surgery and postoperative conditions: Compared with the CS group, the LS group presented less intraoperative blood loss [50.0 (50.0-100.0) ml vs. 100.0 (100.0-100.0) ml, Z=-3.111, P=0.002] and earlier time to flatus [(3.1±0.8) days vs. (3.5±1.1) days, t=-2.490, P=0.014]. However, there were no statistically significant differences between two groups of patients in terms of operation time, time to start a liquid diet and postoperative hospital stay (all P>0.05). (2) Postoperative complications: The early complication rates of the CS group and the LS group were 22.1% (17/77) and 18.9% (10/53), respectively, while the late complication rate were 18.2% (14/77) and 15.1% (8/53), respectively, whose differences were not statistically significant (all P>0.05). (3) Postoperative quality of life: After 1-year follow-up, 7 (5.4%) patients were lost, including 5 in CS group and 2 in LS group. One year after operation, the QLQ-C30 scale showed that the score of financial difficulty of the LS group was significantly higher than that of the CS group [33.3 (0 to 33.3) vs.0 (0 to 33.3), Z=-1.972, P=0.049] with statistically significant difference, and there were no statistically significant differences in the scores of other functional fields and symptom fields between the two groups (all P>0.05). The QLQ-STO22 scale showed that the scores of dysphagia [0 (0 to 5.6) vs. 0 (0 to 11.1), Z=-2.094, P=0.036] and eating restriction were significantly lower [0 (0 to 4.2) vs. 0 (0 to 8.3), Z=-2.011, P=0.044] in patients of the LS group than those of the CS group. There were no significant differences in scores of other symptoms between two groups (all P>0.05). Conclusions: Compared with the circular stapler, the esophagojejunostomy with linear stapler for gastric cancer patients can reduce intraoperative blood loss, shorten the time to flatus after operation, alleviate the symptoms of dysphagia and eating restriction but increase the economic burden to a certain degree.

[A nomogram for predicting lymph node metastasis in early gastric cancer]

Objective: To explore the independent risk factors of lymph node metastasis (LNM) in early gastric cancer, and to use nomogram to construct a prediction model for above LNM. Methods: A retrospective cohort study was conducted. Inclusion criteria: (1) primary early gastric cancer as stage pT1 confirmed by postoperative pathology; (2) complete clinicopathological data. Exclusion criteria: (1) patients with advanced gastric cancer, stump gastric cancer or history of gastrectomy; (2) early gastric cancer patients confirmed by pathology after neoadjuvant chemotherapy; (3) other types of gastric tumors, such as lymphoma, neuroendocrine tumor, stromal tumor, etc.; (4) primary tumors of other organs with gastric metastasis. According to the above criteria, 1633 patients with early gastric cancer who underwent radical gastrectomy at the Department of General Surgery of the Chinese PLA General Hospital First Medical Center from December 2005 to December 2020 were enrolled as training set, meanwhile 239 patients with early gastric cancer who underwent gastrectomy at the Department of General Surgery of the Chinese PLA General Hospital Fourth Medical Center from December 2015 to December 2020 were enrolled as external validation set. Risk factors of LNM in early gastric cancer were identified by using univariate and multivariate logistic regression analyses. A nomogram prediction model was established with significant factors screened by multivariate analysis. Area under the receiver operating characteristic curve (AUC) was used for assessing the predictive value of the model. Calibration curve was drawn for external validation. Results: Among 1633 patients in training set, the mean number of retrieved lymph nodes was 20 (13-28), and 209 patients (12.8%) had lymph node metastasis. Univariate analysis showed that gender, resection range, tumor location, tumor morphology, lymph node clearance, vascular invasion, lymphatic cancer thrombus, tumor length, tumor differentiation, microscopic presence of signet ring cells and depth of tumor invasion were associated with LNM (all P<0.05). Multivariate analysis revealed that females, tumor morphology as ulcer type, vascular invasion, lymphatic cancer thrombus, tumor length≥3 cm, deeper invasion of mucosa, and poor differentiation were independent risk factors for LNM in early gastric cancers (all P<0.05). Receiver operating characteristic curve indicated that AUC of training set was 0.818 (95%CI: 0.790-0.847) and AUC of external validation set was 0.765 (95%CI: 0.688-0.843). The calibration curve showed that the LNM probability predicted by nomogram was consistent with the actual situation (C-index: 0.818 in training set and 0.765 in external validation set). Conclusions: Females, tumor morphology as ulcer type, vascular invasion, lymphatic cancer thrombus, tumor length≥3 cm, deeper invasion of mucosa and poor differentiation are independent risk factors for LNM of early gastric cancer. The establishment of a nomogram prediction model for LNM in early gastric cancer has great diagnostic value and can provide reference for treatment selection.

[Indications, selection, and effect of flap application in repairing scar carcinoma in the lower leg and ankle]

Objective: To explore the indications, selection, and effect of flap application in repairing scar carcinoma in the lower leg and ankle. Methods: A retrospective cohort study was conducted. From June 2008 to December 2018, six male patients with scar carcinoma in the lower leg and ankle were treated in Sun Yat-Sen Memorial Hospital of Sun Yat-Sen University, aged 48-64 years, with the area of lesion ranging from 3 cm×2 cm to 15 cm×6 cm. After extended resection, the defect area ranged from 8 cm×5 cm to 22 cm×9 cm, with tissue of tendon or bone exposed. Free anterolateral thigh perforator flap, latissimus dorsi myocutaneous flap, or pedicled sural neurovascular flap was selected to repair the wound according to the location of wound in the lower extremity, selection of operation position, the location of the anastomotic vessels in the recipient area, and whether there was good skin and soft tissue available in the lower leg. The size of flap was 11 cm×8 cm-26 cm×10 cm. The donor site of free flap or myocutaneous flap was closed directly by suturing in 5 cases, and the donor site of pedicled flap was repaired with full-thickness skin graft in 1 case. The blood supply and survival of flap, quality of skin graft survival, and complication were observed postoperatively. During the follow-up period, the recurrence and metastasis of scar carcinoma, and the appearance and function of donor and recipient sites were observed. Results: All the patients completed the operation successfully, all the transplanted flaps survived with good blood supply, and the skin graft in one donor site survived well. The wounds in the donor and recipient sites of all the patients healed well without infection, effusion, or dehiscence, etc. All the patients were followed up for 1-5 years. No local recurrence or distant metastasis of scar carcinoma was found. The quality of the transplanted flaps was good. The shape of the recipient area was quite good, and the function of the affected limb was fine. The appearance of the donor area was good without dysfunction. Conclusions: Flap transplantation is suitable for the patients with tendon and bone exposure after the excision of scar carcinoma in the lower leg and ankle. The flap can be selected according to the location of scar carcinoma, operation position, the location of anastomotic vessels in the recipient area, and whether there is good skin and soft tissue available in the lower leg. The free anterolateral thigh perforator flap or latissimus dorsi myocutaneous flap is an ideal choice for repair, which can be obtained in a large area, and the donor site can be directly sutured without affecting the function.

[Risk factors of postoperative complication after total gastrectomy in advanced gastric cancer patients receiving neoadjuvant chemotherapy]

Objective: At present, there are few studies focusing on the factors short-term complications after total gastrectomy in patients with advanced gastric cancer receiving neoadjuvant chemotherapy (NACT). The purpose of this study is to provide a reference for clinical prevention of complications in these patients. Methods: A retrospective case-control study was conducted. Case inclusion criteria: (1) clinical stage II-III gastric cancer diagnosed by preoperative gastroscopy, pathology, abdominal CT, EUS or PET-CT; (2) evaluated suitable for NACT by MDT discussion; (3) no previous history of other malignant tumors and no concurrent tumor; (4) undergoing total gastrectomy+ D2 lymphadenectomy after NACT. Exclusion criteria: (1) age <18 or >80 years old; (2) severe concurrent diseases, and ASA classification>grade III; (3) stump gastric cancer or history of gastric surgery; (4) incomplete clinicopathological data. According to the above criteria, clinicopathological data of 140 advanced gastric cancer patients who underwent total gastrectomy after NACT in Chinese PLA General Hospital between June 2012 and June 2019 were collected, including 109 males and 31 females with mean age of (56.9±11.4) years and body mass indey (BMI) of (23.3±3.1) kg/m(2). Logistic analysis was used to analyze the relationship between postoperative complication and clinicopathological data. Factors in univariate analysis with P<0.05 were included in the multivariate analysis. Results: Postoperative complications (Clavien-Dindo classification ≥ II) occurred in 35 cases (25.0%) and severe complications (Clavien-Dindo classification ≥ IIIa) occurred in 4 cases (2.9%), including 1 case of esophago-jejunal anastomotic leakage, 1 case of vena cava thrombosis, 1 case of pleural effusion, 1 case of septic shock during perioperative days resulting in death. Univariate analysis showed that BMI (P=0.011), cycle of NACT (P=0.027), tumor diameter (P=0.021), and vascular invasion (P=0.033) were associated with postoperative complication within 30 days, while open/laparoscopic total gastrectomy were not associated with postoperative complication (P=0.926). Multivariate analysis revealed that BMI ≥ 25 kg/m(2) (OR=3.294, 95% CI: 1.343-8.079, P=0.009) and < 4 cycles of NACT (OR=2.922, 95% CI: 1.217-7.016, P=0.016) were independent risk factors for postoperative complication. The 3-year overall survival rates of patients with or without complication were 54.4% and 64.0%, respectively (P=0.395), and 3-year disease-free survival rates were 47.4% and 52.9%, respectively (P=0.587). Conclusions: Higher BMI and fewer cycles of NACT are independent risk factors of postoperative complication in advanced gastric cancer patients undergoing total gastrectomy after NACT. No obvious association is found between postoperative complication and surgical approaches.

[Analysis of clinicopathologic characteristics of gastric cancer patients undergoing gastrectomy based on a single-center gastric cancer database with above 10 000 cases]

Objective: The storage of medical data has been digitized in China, but a unified and structured model has not yet been established. The standardized collection, analysis and sorting of tumor clinical data is the foundation of improving the standard of tumor diagnosis and treatment. Therefore, establishing a database platform of gastric cancer (GC) is an urgent need to integrate data resources and improve the level of diagnosis and treatment. The population economics indexes of GC patients in the last 20 years are analyzed in a single-center GC database. The medical records were structured by natural language processing technology. Authors aim to investigate the clinical pathological characteristics, staging and survival of the GC patients with gastrectomy. Method: A retrospective cohort study was carried out. Clinicopatological data of patients receiving surgical treatment from 2000 to 2019 were retrospectively collected. According to the gastric cancer TNM staging guidelines from the Union for International Cancer Control and the American Joint Committee on Cancer (UICC/AJCC) 8th edition, the structured gastric cancer clinicopathological data were re-evaluated and interpreted. The Kaplan-Meier method and the log-rank test were used to compare survival rate among different groups of patients with complete follow-up data of 2010-2016. Results: Clinicopathological data of 13 492 GC patients were enrolled. The ratio of men to women in the whole group was 3.25:1.00, including 10 320 men with average onset age of 59.68 years, which was basically stable in recent 20 years, and 3172 women with average onset age of 55.93 years, which presented a trend of average increasement of 0.17 year per year. The average hospitalization duration for GC patients showed a decreasing trend year by year, which was 13.87 days in 2019. Average hospitalization cost for GC patients was increasing year by year, with a peak of 83 600 CNY in 2017 and 75 400 CNY in 2019. By natural language identification and exclusion criteria screening, a total of 7218 GC patients obtained structured clinicopathological information. Analysis on clinicopathological characteristics of 3626 GC patients in the last 5 years showed that the average diameter of tumor was (4.44±2.61) cm; the average number of harvested lymph node was 24.30±13.29; the proportion of surgical methods were as following: open surgery in 1398 cases (38.55%), laparoscopic surgery in 1856 cases (51.19%) and robotic surgery in 372 cases (10.26%). The postoperative pathological stage was as following: IA in 658 cases (18.15%), IB in 318 cases (8.77%), IIA in 559 cases (15.42%), IIB in 543 (14.98%), III A in 632 (17.43%), III B in 612 cases (16.88%), III C in 276 cases (7.61%), and IV in 28 cases (0.77%). Complete follow-up data of 3431 patients from 2010 to 2016 were presented. The 1-, 3- and 5-year survival rates were 82%, 69% and 60%, respectively for the whole group. The 1-, 3- and 5-year survival rates for patients undergoing laparoscopic surgery were 83%, 70% and 64%, respectively, and for those undergoing open surgery were 81%, 67% and 56%, respectively, and the difference between the two groups was not statistically significant (P=0.109). The 5-year survival rate of GC patients with different AJCC stages was as following: 88% in IA, 77% in IB, 70% in II A, 62% in II B, 44% in III A, 32% in III B, 22% in III C, and 17% in IV. Conclusion: This study provides basic data for the establishment of comprehensive diagnosis and treatment model of multicenter, shedding light on the improvement of comprehensive treatment of GC in China.

[Clinical analysis of missed diagnostic congenital cholesteatoma]

Objective:The clinical symptoms, imaging features and surgical treatment of congenital cholesteatoma are reported. Method:The clinical data of 20 patients with congenital cholesteatoma diagnosed and treated in our hospital from January 2016 to May 2018 were retrospectively analyzed, including the age of onset, clinical symptoms, signs, audiology, HRCT of temporal bone, surgical methods and so on. Result:In 20 patients with congenital cholesteatoma, the clinical manifestations were hearing loss in the affected ears, including 5 cases with ear fullness and 4 cases with tinnitus. There were 13 cases of local yellow-white shadow of tympanic membrane, 5 cases of normal tympanic membrane and 2 cases of tympanic membrane bombe. Pure tone audiometry showed conductive deafness in 14 cases and mixed deafness in 6 cases. CT scan of temporal bone showed that 15 cases had pneumatic type of mastoid, 4 cases had diploectic type and 1 case had sclerostic type. There were 15 cases of interspersed flocculent shadow and 5 cases of mass shadow. Among the 20 cases of chronic otitis media with cholesteatoma, 6 have cholesteatoma in epitympanum, 4 in tympanic cavity, 3 in tympanic cavity and epitympanum, 2 in mastoid and tympanic antrum, 1 in mastoid, tympanic antrum and tympanic cavity, 1 in tympanic antrum, tympanic cavity and petrous apex, 1 in tympanic cavity, hypotympanum, posterior tympanum and ostium tympanicum tubae auditivae, 1 in aditus ad antrum, epitympanum and posterior tympanum, 1 in tympanic cavity, epitympanum and posterior tympanum. Intact canal wall mastoidectomy and tympanoplasty were performed in 7 cases, open mastoidectomy and tympanoplasty in 5 cases, middle ear exploration and tympanoplasty in 4 cases, atticotomy with reconstruction and tympanoplasty in 3 cases and subtotal temporal bone resection in 1 case. Conclusion:For patients with intact tympanic membrane presenting with hearing loss, the tympanic membranes should be carefully examined, and thin-section CT and MRI of temporal bone should be performed in time to avoid missed diagnosis of congenital cholesteatoma. Once diagnosed, surgery should be performed as soon as possible.

[Network correlation of circRNA-miRNA and the possible regulatory mechanism in acute myocardial infarction]

Objective: Using microarray technology, to research characteristic circRNA and miRNA expression profile of acute myocardial infarction (AMI), and then explore the role of these circRNA and miRNA in gene regulation. The aim is to explore the mechanism of development of AMI. Methods: The patients hospitalized in the Cardiovascular Research Center of the First Affiliated Hospital of Xinxiang Medical University between November 2016 and January 2017 were included and divided into control group and AMI group according to diagnostic criteria. We collected their whole blood and extracted the total RNA, and the expression profiles of circRNA and microRNA genes in peripheral blood of AMI were analyzed by gene chip. We predicted circRNA which was possible to combine with miRNA, and drew a network diagram, and the differentially expressed circRNA was analyzed by GO and Pathway. Results: There was difference in circRNA expression profile between the control group and the AMI group. The results showed: (1) a total of 1 670 circRNA had differential expressions, and in the analysis of miRNA expression, 13 miRNA had differential expressions (P<0.05, fc≥2); (2) multiple circRNAs-miRNAs were involved in the occurrence of AMI; (3) the analysis of GO and Pathway for differentially expressed circRNAs showed that many pathways, disease and function participated in it. Conclusion: CircRNA, as an important post transcriptional regulator, is closely related to the development of AMI with miRNA.

[Cause analysis of non dry ear after canal wall down mastoidectomy]

Objective:To investigate the possible causes of non dry ear after canal wall down mastoidectomy(CWD).Method:Clinical data of 42 patients undergoing revision CWD in our hospital were analyzed retrospectively,which included history,symptoms,signs,audiological examination,imaging examination, intraoperative findings and postoperative follow-up.All patients underwent CWD and tympanoplasty under general anesthesia.Result:Twenty-six cases were insufficient opened of sinodural angle,36 cases remained mastoid air cell(9 cases is mastoid tip air cell remained),13 cases were inadequate exposured of anterior epitympanic recess, 23 cases were inadequate exposured of posterior tympanum, 25 cases had high facial ridge, posterior facial nerve and labyrinth air cell were 5 cases,3 cases had granulation in round window, 5 cases had dysfunctional eustachian tube, 32 cases had narrow external acoustic meatus. During 3 months,6 months and 1 year follow-up, all 42 cases patients under revision CWD presented with dry ears.Conclusion:Insufficient opened of sinodural angle and mastoid air cell,inadequate exposured of anterior epitympanic recess and posterior tympanum, high facial ridge, narrow external acoustic meatus are all the possible causes of no-dry ear after CWD; As the location of concealment, posterior facial nerve and labyrinth air cell are difficult to clean. The dressing cavity do not be cleaned in time after operation is also the underlying cause of postoperative non-dry ear.

Lengthening the pedicle of the rectus abdominis myocutaneous flap for repair of upper chest and neck defects

INTRODUCTION The aim of this study was to investigate whether the pedicle of the rectus abdominis flap can be lengthened by resecting the inferior costal cartilage segments or associated muscle when repairing upper body defects. A formula was generated that calculates the expected increase in pedicle length. METHODS Thirty patients underwent computed tomography. The width and thickness of the third to seventh inferior costal cartilage segments as well as the width of the respective intercostal spaces were recorded. Four patients underwent reconstruction of an upper body defect with the relevant flap. RESULTS The expected mean increases in pedicle length were 4.07cm (standard deviation [SD]: 0.31cm) and 4.63cm (SD: 0.54cm) following resection of the left and right sides respectively of the seventh inferior costal cartilage segment, 7.99cm (SD: 0.49cm) and 10.82cm (SD: 0.23cm) following resection of the left and right sides respectively of the sixth and seventh inferior costal cartilage segments while resection of the fourth to seventh inferior costal cartilage segments would equate to increases of 17.48cm (SD: 0.62cm) and 22.05cm (SD: 0.21cm) for the left and right sides respectively. In four patients who required reconstruction, three flaps survived without problems but one flap developed partial necrosis. CONCLUSIONS Resecting inferior costal cartilage segments or associated muscle can lengthen the pedicle of the rectus abdominis flap for reconstruction of defects on the upper chest and neck.

Identification of microRNAs as diagnostic biomarkers in screening of head and neck cancer: a meta-analysis

Head and neck cancer (HNC) is one of the most prevalent cancers; it is often diagnosed at its advanced stage and has a low 5-year survival rate. Evidence suggests that noninvasive biomarker microRNAs (miRNAs) are valuable for early diagnosis of HNC. This meta-analysis assessed the diagnostic value of miRNAs in HNC detection. A systematic literature search for relevant studies up to August 4, 2014 was conducted in databases and other sources. Statistical analysis was conducted using STATA 12.0. Pooled sensitivity, specificity, and other parameters, together with a summary receiver operating characteristic curve were used to assess the overall performance of miRNA assays. Subgroup analyses and meta-regression were used to analyze heterogeneity, and a Deeks' funnel plot asymmetry test assessed publication bias. Twenty-four articles with 1856 HNC patients and 1375 controls were included. The pooled results were as follows: sensitivity, 0.80 (95%CI = 0.77-0.83); specificity, 0.80 (95%CI = 0.76-0.85); positive likelihood ratio, 4.1 (95%CI = 3.2-5.2); negative likelihood ratio, 0.25 (95%CI = 0.21-0.30); diagnostic odds ratio (DOR), 16 (95%CI = 11-24); and area under curve (AUC), 0.87 (95%CI = 0.84-0.89). We conducted subgroup analyses based on ethnicity, cancer type, miRNA profiling, and specimen types, and found that miRNA assays yielded the highest accuracy in esophageal cancer. Notably, the DOR was 99 and the AUC was 0.96 for the multiple miRNA test, indicating strong discrimination of cancer patients from healthy people. The meta-analysis indicates that noninvasive miRNAs are a promising diagnostic tool with moderate accuracy for HNC diagnosis.

Pre-treatment with Cobra venom factor alleviates acute lung injury induced by intestinal ischemia-reperfusion in rats

BACKGROUND

Previous studies have shown that complement activation is required for intestinal ischemia-reperfusion (IIR)-induced tissue damage. Cobra venom factor (CVF), a structural and functional homolog to the activated form of C3 (the central component of the complement system), can cause exhaustive activation of the alternative pathway and deplete the complement components.

AIM

This study aims to investigate the effect of CVF pretreatment on acute lung injury induced by IIR in rats.

MATERIALS AND METHODS

Lung injury was induced by clamping superior mesenteric artery (SMA) for 60 min followed by 4 h of reperfusion. CVF was given via the tail vein 24 h before the operation.

RESULTS

Histological results as well as lung edema determination and permeability assay showed the severe damages were induced in the lungs of rats in the IIR group, accompanying with the increases in the levels of pulmonary malondialdehyde (MDA), myeloperoxidase (MPO) activity, intercellular adhesion molecule-1 (ICAM-1), interleukin (IL)-8. Remarkably, CVF pretreatment significantly attenuated the morphological lung injury, lung edema and lung permeability, reduced the increase of the levels of MDA, MPO, ICAM-1 and IL-8 induced by IIR. In addition, the severe damage of intestinal and elevation of plasma diamine oxidase activity in the IIR rats were significantly alleviated by CVF pretreatment.

CONCLUSIONS

CVF pretreatment could significantly reduce the acute lung injury induced by IIR. The mechanism might include, at least in part, the inhibition of oxidant generation, infiltration of neutrophils, ICAM-1 expression and IL-8 release. CVF might be an efficient reagent for preventing the IIR injuries in clinical condition.

Synergistic effects of ethosomes and chemical enhancers on enhancement of naloxone permeation through human skin

The purpose of this study was to investigate the effects of ethosomes, chemical enhancers and their binary combination on the in vitro permeability enhancement of naloxone through human skin. Franz diffusion cells were used for the percutaneous absorption studies. Propylene glycol (PG), N,N-dimethyl formamide (N,N-DMF), N,N-dimethyl acetamide (N,N-DMA), dimethyl sulfoxide (DMSO), Azone and polyethylene glycol 400 (PEG400), were chosen as the chemical enhancers. Naloxone ethosomes showed 11.68 times increase in steady-state flux compared to phosphate buffered solution (PBS). Ethosomes in combination with chemical enhancers synergistically increased (p < 0.05) in vitro flux of naloxone. Azone 3% + PG7% pretreated in ethosomal form dramatically enhanced the skin permeation of naloxone in vitro compared with ethosomes (steady-state flux: 96.75 +/- 5.70 microg x cm(-2) x h(-1) vs 20.56 +/- 1.67 microg x cm(-2) x h(-1)). Ethosomal carrier and enhancers accumulated in the skin after 24 h were greater than that of PBS.

Prediction of plasma protein binding of cephalosporins using an artificial neural network

An artificial neural network model is developed to predict the fraction of cephalosporins bound to plasma proteins (f(b)) from their molecular structural parameters. These molecular structural parameters are the molecular weight (MW), the surface area occupied by oxygen and nitrogen atoms (S(O),N), and the surface area occupied by hydrogen atoms attached to oxygen or nitrogen atoms (S(H)). For a training set of 20 cephalosporins and a test set of 3 cephalosporins, root mean squared errors (RMSE) between experimental fb values and calculated/predicted fb values are 0.036 and 0.045, respectively.

Pluronic F127 gel effectively controls the burst release of drug from PLGA microspheres

To investigate the controlled release effect of a thermo-sensitive gel, Pluronic F127 (PF127) on microspheres, poly[D,L-lactic-co-glycolic acid] (PLGA) microspheres were coated with Pluronic F127 gel and the in vitro release was evaluated. The results demonstrated that PF127, which gelled at 37 degrees C, inhibited the initial burst release of drug from microspheres effectively.

Branched-chain alkanols as skin permeation enhancers: quantitative structure-activity relationships

One long-standing approach for improving transdermal drug delivery is using penetration enhancers which reversibly decrease the skin barrier resistance. Though the skin permeation enhancement effect of chemical penetration enhancers has been studied extensively, their quantitative structure-activity relationships have not been adequately investigated. In this paper, we established the correlation equations between enhancement potencies and the physico-chemical parameters relevant to lipophilicity and position of hydroxyl group for 16 alkanols using the stepwise multiple linear regression analysis. These equations reveal that the enhancement potencies of alkanols are excellently correlated with their lipophilicity and position of the hydroxyl group. The enhancement potency of an alkanol will increase when it has greater lipophilicity but will decrease as the hydroxyl group moves from the end of the alkyl chain towards the center.

Prediction of human intestinal absorption using an artificial neural network

An artificial neural network model is developed to predict percent human intestinal absorption (%FA) of compounds from their molecular structural parameters. These parameters are the polar molecular surface area (PSA), the fraction of polar molecular surface area (FPSA, polar molecular surface area/ molecular surface area), the sum of the net atomic charges of oxygen atoms (Q(O)), the sum of the net atomic charges of nitrogen atoms with net negative atomic charges (Q(N)), the sum of the net atomic charges of hydrogen atoms attached to oxygen or nitrogen atoms (Q(H)), and the number of carboxyls (nCOOH). For a training set of 85 compounds anda test set of 10 compounds, root mean squared errors (RMSE) between experimental %FA valuesand calculated/predicted %FA values are 8.86% and 14.1%, respectively.

Optimization and characterization of chitosan-coated alginate microcapsules containing albumin

In order to obtain small microcapsules with high protein encapsulation efficiency and extended release characteristics various processing factors were studied. Bovine serum albumin-loaded alginate microcapsules were prepared by an emulsion method and further incubated in chitosan. Many process factors were tested including the concentration and molecular weight of alginate, the concentration and pH of chitosan, and surfactants, etc. Microcapsules were achieved with diameters less than 2 microm, high encapsulation efficiency (> 80%) and high loading rate (> 10% w/w). The results also showed that the initial BSA amount of 20%-30% loaded alginate microcapsules coated with 0.2%-0.5% chitosan solutions at pH 4 by the two-stage procedure present the best sustained releasing characteristics.

Cationic niosomes as gene carriers: preparation and cellular uptake in vitro

Cationic niosomes of sorbitan monoesters were prepared using film hydration method and tested for their effect on delivery of antisense oligonucleotides (OND) in a COS-7 cell line. These formulations showed positive results on cellular uptake of antisense oligonucleotides. Especially, cationic niosomes of Span 40 and 60 have a more significant effect.

A simple predictive model for blood-brain barrier penetration

A simple two-descriptor model to predict blood-brain barrier penetration is derived from a training set of 79 compounds: log BB = - 13.31V2 + 9.601V - 2.231PSA - 0.5290 (n = 79, r2 = 0.83) where log BB is the logarithm of the ratio of the steady-state concentration of the compound in the brain to in the blood, V (nm3) is the molecular volume, PSA (nm2) is the polar surface area which is defined as the sum of the van der Waals surface areas of oxygen atoms, nitrogen atoms, and attached hydrogen atoms in a molecule, n is the number of compounds, and r is the correlation coefficient. The model is validated by a leave-one-out procedure and an external test set (25 compounds). The results indicate that the model developed is statistically sound and is sufficiently reliable and robust for predictive use. The descriptors in the model can be easily computed and it is suitable for the rapid prediction of the blood-brain barrier penetration for a wide range of drug candidates.

Prediction of drug release from HPMC matrices: effect of physicochemical properties of drug and polymer concentration

A working equation to predict drug release from hydroxypropyl methylcellulose (HPMC) matrices was derived using a training set of HPMC matrices having different HPMC concentration (w/w, 16.5-55%) and different drugs (solubilities of 1.126-125.5 g/100 ml in water and molecular volumes of 0.1569-0.4996 nm(3)). The equation was log(M(t)/M( infinity ))=-0.6747+1.027 log t -0.1759 (log C(s)) log t +0.4027 (log V) log t -1.041C(H) +0.3213 (log C(s)) C(H) -0.4101 (log V) C(H) -0.3521 (log V) log C(s) (n=263, r=0.9831), where M(t) is the amount of drug released at time t, M( infinity ) the amount of drug released over a very long time, which corresponds in principle to the initial loading, t the release time (h), C(s) the drug solubility in water (g/100 ml), V the volume of drug molecule (nm(3)), and C(H) is HPMC concentration (w/w). The benefit of the novel model is to predict M(t)/M( infinity ) values of a drug from formulation and its physicochemical properties, so applicable to the HPMC matrices of different polymer levels and different drugs including soluble drugs and slightly soluble drugs.

A mathematical model to predict the release of water-soluble drugs from HPMC matrices

A mathematical model to predict the fraction of water-soluble drug released as a function of release time (t, h), HPMC concentration (CH, w/w), and volume of drug molecule (V, nm3) was derived with ranitidine hydrochloride, diltiazem hydrochloride, and ribavirin as model drugs. The model is log (M(t)/M(infinity)) = 0.5 log t-0.3322CH-0.2222V-0.2988 (n = 140, r = 0.9848), where M(t) is the amount of drug released at time t, M(infinity) is the amount of drug released over a very long time, which corresponds in principle to the initial loading, n is the number of samples, and r is the correlation coefficient. The model was validated using isoniazid and satisfactory results were obtained. The model can be used to predict the release fraction of various soluble drugs from HPMC matrices having different polymer levels.

A predictive model for the release of slightly water-soluble drugs from HPMC matrices

A model to predict the fraction of slightly water-soluble drug released as a function of release time (t, h), HPMC concentration (C(H), w/w), drug solubility in distilled water at 37 degrees C (C(s), g/100 mL), and volume of drug molecule (V, nm3) was derived when theophyline, tinidazole, and propylthiouracil were selected as model drugs. The model is log (M(t)/M(infinity)) = 0.8683 logt-0.1930C(s) logt + 0.5406V logt-1.227C(H) + 0.1594C(s) + 0.4423C(H)C(s) - 0.8655 (n = 130, r = 0.9969), where Mt is the amount of drug released at time t, Minfinity is the amount of drug released over a very long time, which corresponds in principle to the initial loading, n is the number of samples, and r is the correlation coefficient. The model was validated using sulfamethoxazole and satisfactory results were obtained. The model can be used to predict the release fraction of variousslightly water-soluble drugs from HPMC matrices having different polymer levels.

Limitation of Potts and Guy's model and a predictive algorithm for skin permeability including the effects of hydrogen-bond on diffusivity

The Potts and Guy's model for skin permeability, log P = alpha log K - beta MV + delta where P is the permeability coefficient of a compound from aqueous solution through human skin in vitro, K and MV are octanol-water partition coefficient and molecular volume of the compound respectively, and alpha, beta, delta are constants, is examined for a data set of 53 miscellaneous compounds. The model will result in over-estimation for penetrants having higher hydrogen-bond donor activity and underestimation for penetrants having no hydrogen-bond donor. A predictive algorithm for skin permeability including the effects of hydrogen-bond on diffusivity is proposed: log P = alpha log K - beta MV - gamma Hb + delta where Hb is the descriptor of hydrogen-bonding capacity of penetrants and gamma is a constant. The calculated log P values from the latter model are in good accordance with respective experimental ones for the data set.

Evaluation of different methods to determine the loading of proteins in PLGA microspheres

Various determination methods for protein encapsulation efficiency of PLGA microspheres were compared. Acetonitrile is recommended as an extraction solvent.

Predicting blood-brain barrier penetration of drugs using an artificial neural network

An artificial neural network model is developed to predict the ratios of the steady-state concentrations of drugs in the brain to those in the blood (log BB) from their molecular structural parameters. These molecular structural parameters are the molecular volume (V), the sum of the absolute values of the net atomic charges of oxygen and nitrogen atoms which are hydrogen-bond acceptors (Q(O, N)), and the sum of the net atomic charges of hydrogen atoms attached to oxygen or nitrogen atoms (Q(H)). For a training set of 56 compounds and a test set of 5 compounds, root mean squared errors (RMSE) between experimental log BB values and calculated/predicted log BB values were 0.236 and 0.258, respectively. These molecular structural parameters can be obtained easily from quantum chemical calculations. The model is suitable for the rapid prediction of the blood-brain barrier penetration of drugs.

Effect of Pluronic on cellular uptake of cationic liposomes- mediated antisense oligonucleotides

Cationic liposomes modified by different Pluronic block copolymers were prepared. The influence of Pluronic on the cellular uptake of antisense oligonucleotides (ODN) based on cationic 3beta[N-(N', N'-dimethylaminoethan)-carbamoyl] cholesterol (DC-Chol) liposomes was studied by flow cytometric analysis. It showed that DC-Chol liposomes containing Pluronic gave 1.7-2.3 times higher capacity of cellular uptake of ODN, despite the diminution of ODN loading efficiency. The level of improvement by Pluronic is related to the hydrophobic propylene oxide (PO) units Pluronic contains as well as the lipophile/hydrophile value of the molecule. This preliminary study indicated that modifying liposomes with another excipient is a useful pharmaceutical technique to improve ODN delivery.

A comparative study of electroporation and iontophoresis for percutaneous penetration of naproxen

Using side-by-side compartment diffusion cell and rat skin, the in vitro percutaneous penetration of naproxen by electroporation and iontophoresis with different energy was investigated and compared. Both electroporation and iontophoresis could obviously increase the penetration of naproxen through rat skin. The enhancing effect of electroporation was not always better than that of iontophoresis. The enhancing effect was dependent on the energy of the electrical field.

[Application of an artificial neural network in the design of sustained-release dosage forms]

AIM

To use the artificial neural network (ANN) in Matlab 5.1 tool-boxes to predict the formulations of sustained-release tablets.

METHODS

The solubilities of nine drugs and various ratios of HPMC: Dextrin for 63 tablet formulations were used as the ANN model input, and in vitro accumulation released at 6 sampling times were used as output.

RESULTS

The ANN model was constructed by selecting the optimal number of iterations (25) and model structure in which there are one hidden layer and five hidden layer nodes. The optimized ANN model was used for prediction of formulation based on desired target in vitro dissolution-time profiles. ANN predicted profiles based on ANN predicted formulations were closely similar to the target profiles.

CONCLUSION

The ANN could be used for predicting the dissolution profiles of sustained release dosage form and for the design of optimal formulation.

[Population pharmacokinetic model for gentamycin and its predictive value]

AIM

To construct a population pharmacokinetic model to describe gentamycin concentrations in serum in newborn infants and to validate the predictive ability of this model.

METHODS

Data used in this study were obtained from 30 neonates with 80 serum samples. A one-compartment open model was used to describe the kinetics of gentamycin after intravenous infusion. Following Sheiner's idea of population pharmacokinetics, a programs to estimate population parameter and individual parameter of gentamycin was made. The target function minimality was obtained from Monte Carlo algorithm. The predictive ability of the developed model was evaluated by computing precision and accuracy of serum concentration predicted using the parameter estimates.

RESULTS

Fitted population pharmacokinetic parameters (mean +/- standard deviation) were as follows: Ke: 0.220 +/- 0.022 h-1, Vd: 0.51 +/- 0.06 L.kg-1, Cl: 112 +/- 10 mL.h-1.kg-1. For the population analysis sample and the predictive sample, predicted and observed concentrations were all close with correlation coefficient 0.920 and 0.946, respectively. Mean prediction error (ME) and root mean squared error (RMSE) were 0.001 mg.L-1 and 0.84 mg.L-1 for the predictive sample, respectively.

CONCLUSION

Observed gentamycin serum concentrations were explained very well by this model. We propose the use of this population pharmacokinetic model to optimize gentamycin clinical therapies in our institution and others with similar patient population characteristics.

Predicting blood-brain barrier penetration of drugs by polar molecular surface area and molecular volume

AIM

To predict the blood-brain barrier penetration by polar molecular surface area and molecular volume.

METHODS

Polar molecular surface area and molecular volume are calculated by Monte Carlo method from the lowest energy conformation obtained using the semiempirical self-consistent field molecular orbital calculation AM1 method. The stepwise multiple regression analysis is used to derive the correlation equations between the ratios of the steady-state concentrations of the training compounds in the brain to in the blood (logBB)and their structural parameters.

RESULTS

For a training set of 56 compounds, logBB values are well correlated with the sums of surface areas of oxygen and nitrogen atoms (SO,N, A2, excluding the nitrogen atoms in nitrogen molecule or in nitro) and molecular volumes (V, A3). The regression equation is logBB = -1.331 x 10(-5)V2 + 9.228 x 10(-3)V -0.02439 SO,N -0.4318 (n = 56, r = 0.9043). The calculated logBB values of a test set of 10 compounds from the model agree well with their experimental logBB values.

CONCLUSION

The model is simple and effective. It can be used to predict the logBB values of candidate molecule in drug design.

[Immunogold localization of ribulose-1,5-bisphosphate carborylsae/oxygenase in chloroplasts of Chlorella]

Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a first key enzyme in the Calvin Circle of plant cell photosynthesis. This paper mainly studied gold immunolocalization of Rubisco of Chlorella spp. 640909, and the Native-PAGE and, SDS-PAGE and Western bloting analysis, as well as the observation to pyrenoid ultra structure. The Native-PAGE result showed a main band, evidenced as the Rubisco band by the Western blot with the antibody against the Rubisco from C. prototothecoides, The special immunoacton of Rubisco from Chlorella spp. 640909 and the antibody to large subunit of Rubisco from C. prothecoides showed the large subunit proteins of Rubisco in the two species of Chlorella shared the high homology. The SDS-PAGE and Western blotting maps showed the molecule weight of the large subunit of Rubisco of Chlorella spp. 640909 was about 55 KD. The shape of pyrenoid ultra structure of the electronic microscope was oblong, and was embedded in starch sheath, with 2 swelling thylakoids through out a center portrait channel of the pyrenoid. There were some connections between pyrenoid and the chloroplast stroma. The distribution of the large subunits and the whole Rubisco in the chloroplast of Chrolella spp. 640909 was studied by immunoelectron microscopy by embedded sections with antibody to large subunit and whole enzyme followed by second antibody, goad anti-rabbit immunoglobulin G conjugated to 10 nm gold particles(Sigma production). The result showed the antibodies against large subunit and whole enzyme heavily labeled the pyrenoid, as well as starch sheath region, whereas the thylakoid region of the plastid was lightly labeled. And the whole Rubisco antibody labeled the pyrenoid surface more heavily than the large subunit antibody did. It is demonstrated the pyrenoid and starch sheath have the photosynthesis function. Rubisco concentrating in pyrenoid and starch sheath is valuable to fix CO2 for photosynthesis in algae.

[Predicting skin permeability of drugs with theoretical parameters]

AIM

To predict skin permeability of drugs with theoretical parameters.

METHODS

The semiempirical self-consistent field molecular calculation AM1 method is utilized to obtain the structural parameters of drug molecules. Stepwise multiple regression analysis or BP network is then utilized to establish the correlation between skin permeability of drugs and their structural parameters.

RESULTS

The calculated human skin permeability coefficients (kp) of 22 model drugs in vitro or the R values (R = absorbed/unabsorbed) of 17 drugs in vivo are in good agreement with their observed values.

CONCLUSION

Theoretical parameters can be used to predict skin permeability of drugs.

Population pharmacokinetic analysis of amikacin and validation on neonates using Monte Carlo method

AIM

To make programs for population pharmacokinetic analysis and to assess the ability of this method in pharmacokinetic parameter estimation and in the prediction of serum concentrations.

METHODS

Data of amikacin as a model drug were collected from 42 neonates with 142 serum samples. A one-compartment open model was used to describe the kinetics of amikacin after the intravenous infusion. Following Sheiner's idea of population pharmacokinetics, we made the programs to evaluate population parameter and individual parameter. The target function minimality was obtained from Monte Carlo algorithm. The validation of the population analysis was performed using classic pharmacokinetic program 3p87 for antithesis. The predictability of the developed method was evaluated by computing precision and accuracy of serum concentration predicted using the parameter estimates.

RESULTS

The stability of our self-made program was good. The population parameters obtained from this approach were in conformity with those from 3p87, and the interindividual variability was relatively small. For the learning sample and the validation sample, predicted and observed concentrations were all close with correlation coefficient 0.995 and 0.990, respectively. Most of predicted errors were found < +/- 1 mg/L, and RMSD and BIAS were 0.58 and -0.07 for the validation sample, respectively. The choice of blood sampling time was an important factor for the predictive performance. An early sampling time after the infusion was observed to be the best sampling time.

CONCLUSION

The estimation program of population parameter and individual parameter made by us ran stably, and allowed us to use sparse data to estimate population pharmacokinetic parameters. It provided accurate estimates of these parameters and satisfactory ability of serum concentration prediction. Therefore, it can be used for the population pharmacokinetic analysis and individualization of dosage regimen.

Expression pattern of (+)-delta-cadinene synthase genes and biosynthesis of sesquiterpene aldehydes in plants of Gossypium arboreum L

The cotton (+)-delta-cadinene synthase, a sesquiterpene cyclase, is encoded by a complex gene family which, based on homology, can be divided into two subfamilies: cad1-A and cad1-C. Southern blots revealed several members of the cad1-C subfamily, and a single member of the cad1-A subfamily, in the diploid Gossypium arboreum genome. One of the cad1-C genes, cad1-C3, was isolated from this species. According to reverse transcriptase-polymerase chain reaction, transcripts of both cad1-C and cad1-A genes appeared in roots from the second day post germination and in 1-d-old cotyledons, whereas the transcription levels were too low to be detected in the hypocotyls. Initially, sesquiterpene cyclase activities were found to be high in the seedlings, then dropped in aerial organs but increased in roots during development. Sesquiterpene aldehyde contents followed the same pattern. In fully developed plants, the transcripts of cad1-C were detected in stems, leaves and pericarps, as well as in the sepals and petals 3 d before anthesis, but not at the day of anthesis. In contrast, cad1-A transcripts were not detected in any of these aerial organs. The sesquiterpene aldehyde contents increased in petals but decreased in sepals after anthesis. Treatment of G. arboreum stems with a Verticillium dahliae elicitor-preparation activated cad1-A transcription, but a significant level of cad1-C transcripts was detected both before and after elicitation. In G. hirsutum cv. GL-5, a glandless cultivar, the cad1-C gene was activated by the same fungal elicitor, followed by the synthesis of the sesquiterpene cyclase, and accumulation of sesquiterpene aldehydes. The cad1 gene expression during development and in response to elicitation, as well as the spatial and temporal pattern of sesquiterpene biosynthesis, constitute a chemical defense machinery in cotton plants.

Coordinated accumulation of (+)-delta-cadinene synthase mRNAs and gossypol in developing seeds of Gossypium hirsutum and a new member of the cad1 family from G. arboreum

A new member of the (+)-delta-cadinene synthase (CAD1) family was isolated from a Gossypium arboreum cDNA library. This cDNA encodes a protein that showed 97.3%, 96.9%, and 79.2% sequence identities with the proteins encoded by previously isolated cDNAs of cad1-C1, cad1-C14, and cad1-A, respectively. It may be grouped into the cad1-C subfamily as cad1-C2. Seeds of a glanded cotton cultivar, G. hirsutum cv. Sumian-6, were collected at different intervals during maturation, and the cad1 mRNA levels were analyzed by quantitative RT-PCR. The transcripts could be detected in seeds of 27 DPA (days postanthesis) and increased dramatically along with the seed maturation, which coordinated with an increase in sesquiterpene cyclase activities and subsequently the accumulation of gossypol. The transcription level detected with primers specific to cad1-C (including at least C1, C14, and cdn1) was higher than that detected with primers specific to cad1-A, and mRNA was detected also with cad1-C2-specific primers. This investigation indicates that, in developing seeds of the glanded cotton cultivar, genes of both the CAD1-C and CAD1-A subfamilies are expressed and there is an active biosynthesis of cadinene-type sesquiterpenes.