Antimicrobial resistance crisis: could artificial intelligence be the solution?

Antimicrobial resistance is a global public health threat, and the World Health Organization (WHO) has announced a priority list of the most threatening pathogens against which novel antibiotics need to be developed. The discovery and introduction of novel antibiotics are time-consuming and expensive. According to WHO's report of antibacterial agents in clinical development, only 18 novel antibiotics have been approved since 2014. Therefore, novel antibiotics are critically needed. Artificial intelligence (AI) has been rapidly applied to drug development since its recent technical breakthrough and has dramatically improved the efficiency of the discovery of novel antibiotics. Here, we first summarized recently marketed novel antibiotics, and antibiotic candidates in clinical development. In addition, we systematically reviewed the involvement of AI in antibacterial drug development and utilization, including small molecules, antimicrobial peptides, phage therapy, essential oils, as well as resistance mechanism prediction, and antibiotic stewardship.

Plasma position measurements by O-mode and X-mode reflectometry systems in tokamak plasmas

Plasma Position Reflectometry (PPR) is planned to provide plasma position and shape information for plasma operation in future fusion reactors. Its primary function is to calibrate the drift of the magnetic signals due to the integral nature of magnetic measurement. Here, we attempt to measure plasma position using ordinary mode (O-mode) and extraordinary mode (X-mode) reflectometry systems on two tokamaks. A new physical model based on the phase shift is proposed to deduce the relative movement of the cut-off layer without density inversion. We demonstrate the plasma position measurements by absolute measurement from density profile inversion and relative measurement from phase shift. The combination of X-mode and O-mode reflectometers can minimize the limitations of single polarization reflectometry and further increase the accuracy of plasma position measurement. These results could provide an important technical basis for the further development of a real-time control system based on PPR.

[The application value of cardiac magnetic resonance quantitative T1 mapping technique for risk stratification in patients with pulmonary arterial hypertension]

Objective: To explore the application value of cardiac magnetic resonance (CMR) native T₁ mapping for risk stratification in patients with pulmonary arterial hypertension (PAH). Methods: A total of 59 patients with diagnosed PAH and clear-documented risk status in Peking Union Medical College Hospital and underwent CMR examination between January 2019 and December 2021 were retrospectively included, which including 12 males and 47 females, aged from 4 to 77 (31±13) years. Those patients were subdivided into two groups based on the clinically-assessed risk status: low-risk group (n=30) and intermediate-/high-risk group (n=29). Twenty-five healthy individuals were included as controls. Base, midventricular, and apical inferior right ventricular insertion point (IRVIP) native T₁ values on short axis images were measured. Native T1 values in PAH patients and control group, in low-risk group and intermediate-/high-risk group were compared, respectively, and receiver operating characteristics (ROC) curves with area under the curves (AUC) were calculated to evaluate the application value of native T₁ values for risk stratification in PAH patients. Results: Base, midventricular and apical IRVIP native T₁ of PAH patients were all significantly increased as compared to controls [Base:(1 439.31±129.96) vs (1 282.36±37.18) ms;midventricular:(1 450.32±111.55) vs (1 287.56±53.16) ms;apical:(1 444.12±109.15) vs (1 266.36±75.31) ms](all P<0.001). The midventricular IRVIP native T₁ values were significantly higher in patients in intermediate-/high-risk status as compared to those in low-risk status [ (1 493.24±126.32) vs (1 428.50±85.73) ms,P=0.026]. The AUC of mid ventricle IRVIP native T₁ for distinguishing patients in intermediate-/high-risk status was 0.741. The base [(1 458.21±134.96) vs (1 421.03±104.75) ms, P=0.241] and apical [(1 465.90±125.36) vs (1 423.07±87.87) ms,P=0.136] IRVIP native T1 values in patients in intermediate-/high-risk group were also numerically higher as compared with patients in low-risk status, however, without statistical significant (both P>0.05). Conclusion: Midventricular IRVIP native T₁ value might have a role for assisting in risk stratification in PAH patients, which was clinically significant for facilitating the work-up and prognosis improvement of PAH patients.

Fecal Microbiota Transplantation Ameliorates Active Ulcerative Colitis by Downregulating Pro-inflammatory Cytokines in Mucosa and Serum

Background

Ulcerative colitis (UC) is a multi-factor disease characterized by alternating remission periods and repeated occurrence. It has been shown that fecal microbiota transplantation (FMT) is an emerging and effective approach for UC treatment. Since most existing studies chose adults as donors for fecal microbiota, we conducted this study to determine the long-term efficacy and safety of the microbiota from young UC patient donors and illustrate its specific physiological effects.

Methods

Thirty active UC patients were enrolled and FMT were administered with the first colonoscopy and two subsequent enema/transendoscopic enteral tubing (TET) practical regimens in The First Affiliated Hospital of Anhui Medical University in China. Disease activity and inflammatory biomarkers were assessed 6 weeks/over 1 year after treatment. The occurrence of adverse events was also recorded. The samples from blood and mucosa were collected to detect the changes of inflammatory biomarkers and cytokines. The composition of gut and oral microbiota were also sampled and sequenced to confirm the alteration of microbial composition.

Results

Twenty-seven patients completed the treatment, among which 16 (59.3%) achieved efficacious clinical response and 11 (40.7%) clinical remission. Full Mayo score and calprotectin dropped significantly and remained stable over 1 year. FMT also significantly reduced the levels of C-reactive protein (CRP), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). The gut microbiota altered significantly with increased bacterial diversity and decreased metabolic diversity in responsive patients. The pro-inflammatory enterobacteria decreased after FMT and the abundance of Collinsella increased. Accordingly, the altered metabolic functions, including antigen synthesis, amino acids metabolism, short chain fatty acid production, and vitamin K synthesis of microbiota, were also corrected by FMT.

Conclusion

Fecal microbiota transplantation seems to be safe and effective for active UC patients who are nonresponsive to mesalazine or prednisone in the long-term. FMT could efficiently downregulate pro-inflammatory cytokines to ameliorate the inflammation.

[Deep learning reconstruction algorithm for coronary CT angiography in assessing obstructive coronary artery disease caused by calcified lesions: the clinical application value]

Objective: To investigate the image quality of coronary CT angiography (CCTA) subjected to deep learning-based reconstruction algorithm (DLR) method and its diagnostic performance for stenosis caused by coronary calcified lesions. Methods: We enrolled 33 consecutive patients with known or suspected coronary artery disease (CAD) who underwent CCTA and subsequently invasive coronary angiography (ICA) within 1 month in the department of radiology, Peking Union Medical College Hospital between February 2020 and February 2021. Among them, there are 26 males and 7 females, age range from 45 to 86 (61.9±9.0) years. The CCTA images were reconstructed with DLR and hybrid iterative reconstruction (HIR). Image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were calculated on the aorta root, left main artery, proximal left anterior descending, left circumflex, and right coronary artery of the CCTA images and were used to evaluate the objective image quality (IQ). Subjective IQ score was graded using Likert four-point scale (1 for excellent and 4 for poor). The diagnostic performance of obstructive coronary artery disease caused by calcified lesions on CCTA subjected to DLR and HIR methods were evaluated using ICA as the reference standard. Results: A total of 123 lesions in 33 patients were included in the analysis. Image noise of DLR image was significantly lower than that on HIR image(defined as the standard deviation of the attenuation values in the aortic root: 18.12±3.66 vs 24.19±5.71, P<0.001), CNR and SNR of DLR image in the aortic root were higher (CNR:43.83±23.73 vs 26.38±9.69, P<0.001,SNR:26.66±7.83 vs 21.23±8.65, P<0.001). Subjective scores of DLR was better than HIR image (1.12±0.41 vs 1.46±0.60,P<0.001). The sensitivity, specificity and accuracy of DLR and HIR images for diagnosing obstructive coronary artery disease caused by calcified lesions were 100.0%, 77.4%, 78.9% and 100.0%, 63.5%, 65.9%%, respectively. The number of false positive cases on DLR image decreased by 38% compared with HIR. Conclusions: Artificial intelligence based DLR can significantly reduce the image noise and improve the image quality of CCTA. DLR helps to improve the diagnostic performance of CCTA in assessing obstructive coronary artery disease caused by calcified lesions, which may have good clinical application value.

A C-type lectin with antibacterial activity in weather loach, Misgurnus anguillicaudatus

C-type lectins are carbohydrate-binding proteins that play important roles in immunity by serving as pattern recognition receptors. In the present study, a novel nattectin-like C-type lectin was obtained from the weather loach, Misgurnus anguillicaudatus, designated as MaCTL. MaCTL encodes a peptide with 165 amino acids, with a signal peptide and a single C-type lectin domain (CTLD), containing a galactose-specific QPD motif and a conserved Ca²⁺ -binding site. Transcripts of MaCTL were significantly upregulated after immune challenge with its pathogen A. hydrophila. In vitro assays with recombinant MaCTL protein revealed that it exhibited hemagglutinating and bacterial agglutinating activities, in a Ca²⁺ -dependent manner. MaCTL was found to bind to a wide range of bacteria, as well as bind to bacterial polysaccharides LPS and PGN. Moreover, MaCTL displayed antimicrobial activity by inhibiting the growth of bacteria. These results collectively suggest that MaCTL is involved in the antibacterial defence of weather loach.

Simultaneous multi-slice accelerated diffusion-weighted imaging with higher spatial resolution for patients with liver metastases from neuroendocrine tumours

AIM

To evaluate the imaging characteristics of simultaneous multi-slice (SMS) accelerated diffusion-weighted imaging (DWI) with decreased section thickness, with and without motion correction, in comparison to conventional DWI (cDWI) for the detection of lesions in patients with neuroendocrine tumour (NET) liver metastases.

MATERIALS AND METHODS

Fifteen patients with NET liver metastases underwent cDWI (section thickness [SL]=4 mm) and SMS-DWI (SL=2 mm). Non-linear motion-corrected (Moco)-SMS-DWI was generated in addition to the original series. Qualitative imaging characteristics (five-point Likert scale), the number of high signal lesions, and the detectability and delineation of lesions were evaluated and compared using the Friedman and the Dunn-Bonferroni tests. The test-retest variability (TRV) of the cDWI and SMS-DWI techniques was investigated among 11 healthy volunteers who underwent cDWI (SL=4 mm) and SMS-DWI (SL=4 mm) twice. The Friedman and the Dunn-Bonferroni post-hoc tests were used to compare the mean apparent diffusion coefficient (ADC) and the TRV in different liver regions between the three series.

RESULTS

Moco-SMS-DWI demonstrated significantly superior overall image quality (p<0.001) with significantly fewer artefacts (p=0.003) than cDWI. The number of lesions detected by cDWI, SMS-DWI, and Moco-SMS-DWI were 348, 504, and 523, respectively. The detectability and delineation of the lesions and the ADC values were significantly higher on the SMS-DWI and Moco-SMS-DWI images than on the cDWI images (all p<0.001). Moco-SMS-DWI showed significantly higher TRV than cDWI in regions near the liver edge (p=0.018).

CONCLUSIONS

SMS-DWI achieves higher spatial resolution than cDWI within the same acquisition time, detects more lesions, and provides better lesion delineation. By applying motion correction, the TRV of DWI could be enhanced in regions near the liver edge.

A triple WAP domain containing protein acts in antibacterial immunity of weather loach, Misgurnus anguillicaudatus

Whey acidic protein domain (WAPD) occurs in a variety of proteins in animals and many of WAPD-containing proteins are involved in immunity. In the present study, a novel protein containing three WAPDs was identified from the weather loach, Misgurnus anguillicaudatus, designated as MaTWD. MaTWD share high identity with TWDs from fish but low identity with TWDs from other animal phyla. MaTWD transcripts mainly distributed in gills and head kidney responded to bacterial challenge with significant upregulation. In vitro assay with recombinant MaTWD protein revealed that MaTWD had antiprotease activity against bacterial proteases. Moreover, MaTWD exhibited bacterial binding capacity and antimicrobial activity. Most importantly, exogenous MaTWD protected loach against bacterial infection by reducing loach mortality. We infer that MaTWD participates in the antibacterial immunity of loach via its antiprotease and antimicrobial activities.

[The mediation mechanism of coronary artery lesions in both male and female patients with Kawasaki disease]

Objective: To explore the mediation mechanism of coronary artery lesion among both male and female Kawasaki disease (KD) children. Methods: Children with KD that hospitalized in the Wenzhou Medical University affiliated Yuying Children's Hospital from January 2009 to December 2014, were included in this study. Differences on demographical characteristics, clinical manifestations, laboratory indicators, regimen and time of treatment, results from pre/post echocardiography and treatment between male and female patients, were compared. The independent effect of gender on the risk of coronary artery lesions (CAL) was evaluated, and the mediating effect of BMI, visiting time and KD type on the association between gender and CAL were also studied. Results: The average BMI level of male patients was higher than that of female patients. The difference was statistically significant (P<0.001). The prevalence of overweight among male patients (20.9%) was higher than female (14.1%). The difference was statistically significant (P=0.011). Data from the multivariate logistic regression analysis confirmed that the incidence of CAL in male patients was higher than that in female patients (aOR=1.50, 95%CI: 1.06-2.12) but the CAL was mainly different before on the immunoglobulin therapy. Results from the mediation analysis showed that BMI was an important mediator in the association between gender and CAL, with the indirect effect as 1.05 (95%CI: 1.01- 1.10) and the proportion mediated as 13.0%. Conclusions: Male patients presented higher incidence of CAL but was mainly reflected in the difference of CAL before the treatment. BMI was probably an important mediator related to the association between gender and CAL.

[Factor analysis of diagnosis and surgical treatment of local regional recurrence in breast cancer patients]

Objective: To analyze the association between clinicopathological factors and clinical diagnosis, treatment and surgery of local regional recurrence (LRR) in breast cancer. Methods: A retrospective study was done to evaluate consecutive 7 823 breast cancer LRR cases between January 2009 and August 2018 at Comprehensive Breast Health Center, Ruijin Hospital, Shanghai Jiaotong University School of Medicine. A total of 108 LRR patients were enrolled: 35 cases (32.4%) with ipsilateral breast tumor recurrence (IBTR) after breast conserving surgery, 40 cases (37.0%) of chest wall recurrence (CR), and 33 cases (30.6%) with regional lymph node recurrence (LNR). All patients were female, aged from 26 to 83 years with a mean of 49 years. Clinicopathological factor and its relationship with different sites of LRR and following surgical choice were analyzed by χ(2) test, rank-sum test and Logistic regression. Survival analysis were performed between different LRR patterns and whether undergoing second surgery. Kaplan-Meier survival curves and Log-rank tests demonstrated the distribution of overall survival. Results: Both univariate analysis and multivariate analysis found that axillary lymph nodes (ALN) status (OR=7.27, 95% CI: 1.30 to 40.53, P=0.042) and disease-free interval (OR=0.18, 95% CI: 0.06 to 0.60, P=0.013) were related to different site of LRR. Compared with patients with IBTR, LNR and CR patients had a higher rate of ALN metastasis and a shorter disease-free interval. A total of 36 LRR patients underwent following surgery. In univariate analysis, initial ALN surgery (χ(2)=16.705, P=0.001), pathological type (χ(2)=7.047, P=0.03), ALN status (χ(2)=10.812, P=0.002), disease-free interval (χ(2)=6.118, P=0.023) and LRR site(χ(2)=19.328, P=0.000) were associated with surgical treatment for LRR patients. Multivariate analysis demonstrated that only site of LRR was independently associated with surgery (OR=0.17, 95% CI: 0.05 to 0.65, P=0.024). The 5-year overall survival was 100% and 60.1% (P=0.018) for LRR patients treated with surgery or not. Furthermore, CR patients had significantly worse overall survival than LNR and IBTR patients, with 5-year overall survival 53.1%, 73.5%, and 100% respectively (P=0.021). Conclusions: Initial lymph nodes metastasis and disease-free interval are associated with different site of LRR. LRR site significantly influenced following surgery choice after LRR, which are both related with overall survival after LRR.

[Prevalence and risk factors of perivascular space in the population of Shunyi Study]

Objective: To investigate the prevalence on imaging, topographic distribution and risk factors of perivascular space (PVS) in community population. Methods: This study was based on the population of Shunyi Study in China from June 2013 to September 2016. One thousand two hundred and thirty-two stroke free participants older than 35 years, who completed cerebral MRI, were included. Cardiovascular risk factors were assessed by interview, physical examination and blood sample tests. PVS were evaluated on high-resolution 3-dimensional-T1WI, T2WI and FLAIR sequences. On T1WI, PVS were detected according to 3D imaging criteria. The number and anatomic location of large PVS (≥3 mm) were recorded. And severity of PVS was then semiquantitatively graded in both white matter (WM) and basal ganglia (BG). Associations between risk factors and PVS were analyzed by multinominal Logistic regression models and adjusted for age, gender and relevant confounders. Results: Perivascular spaces were observed in the BG or WM in every subject, aged (55±10) years and 37.3% male. Large PVS were detected in 19.0% (460/1 232) of participants. Severity of PVS was found to be strongly associated with age in both basal ganglia (severe versus mild: OR=1.81; 95%CI 1.45-2.27, P<0.01) and white matter (OR=1.39; 95%CI 1.13-1.71, P<0.01), and the proportion of subjects with hypercholesterolemia decreased with the severity of PVS in BG (OR=0.58, P=0.01) . The present of large PVS was found to be associated with age(present versus absent: OR=1.03, 95%CI 1.02-1.05, P<0.01) and ApoE ε4 carrier genotype(OR=1.53, 95%CI 1.01-2.23, P=0.04). Conclusions: Perivascular spaces are always detected in the BG or WM in elderly people, and large PVS are also prevalent in community-based population. The risk factors are different due to distribution and size, and may depend on anatomic or pathologic characteristics.

[Value of MRI in the pre-operative diagnosis and classification of oblique vaginal septum syndrome]

Objective: To explore the role of MRI in the pre-operative diagnosis and classification of oblique vaginal septum syndrome (OVSS) . Methods: A retrospective analysis of the clinical records and pre-operative MRI images of 19 patients with surgery proved OVSS was carried out. Two experienced radiologists reviewed the pre-operative pelvic MRI of the 19 patients in consensus blind to the surgery results. Characteristics including malformations of the uterus, cervix and vagina, the diagnosis of the disorder and classification were evaluated. Pre-operative MRI diagnosis and classification were correlated with surgical findings. Results: Mean age of onset of symptoms for the 19 patients was 15 years (ranged 9-25 years) , and mean age of menarche was 12 years. Ten patients suffered from dysmenorrhea or lower abdominal pain, 5 patients complained of vaginal discharge, 3 patients had a history of irregular menstruation, 1 patient suffered from primary infertility. All 19 patients showed uteri didelphys. Eighteen patients showed vaginal oblique septum.One patient showed cervical atresia.MRI was completely correlated with the surgery in the pre-operative diagnosis of OVSS. MRI classification was in line with surgery in 17 patients, including 9 patients with imperforate septum (typeⅠ) , 6 patients with perforate septum (type Ⅱ) , 1 patient with imperforate septum and cervical fistula (type Ⅲ) , and another one with cervical agenesis (type Ⅳ) . One case of type Ⅱ was misdiagnosed as type Ⅰ, another one of type Ⅰ was misdiagnosed as type Ⅲ. Pre-operative MRI classification was correlated with surgery in 17 out of 19 patients. Conclusion: Pre-operative MRI allows excellent manifestation and accurate diagnosis of OVSS, and could also facilitate the evaluation of the classification.

[A cohort study of HIV incidence among injecting drug users in Dehong Prefecture, Yunnan Province]

Objective: To investigate the incidence rates of HIV among injection drug users (IDU) in Dehong Prefecture, Yunnan Province. Methods: We recruited 1 413 HIV-negative IDU attending drug rehabilitation centers and identified a further 1 830 potential participants from a historical database from 2004-2009 using the same criteria. Fingerprint recognition technology was used to confirm the identity of all participants. A total of 3 243 HIV-negative IDU were recruited by the end of 2015, of which 2 546 (78.5%) had been followed up at least once since the initial data collection and 697 (21.5%) were lost to follow-up. Epidemiological data were collected through structured face-to-face interviews which included items on knowledge of AIDS, drug use, sexual activity and history of HIV testing. We collected 3-5 ml of venous blood from each subject for HIV testing. The Chi-squared test was used to compare the characteristics of those IDUs successfully followed up and those lost to follow-up. Results: We identified 226 new HIV cases among the 2 546 respondents-representing 13 907.1 person-years of follow-up and implying an average HIV incidence rate of 1.6 per 100 person-years over the entire study period (95%CI: 1.4-1.9). The incidence rate (per 100 person-years) was 2.6 (95%CI: 2.2-3.1) for the period 2004-2009 and 1.6 (95%CI: 1.0-2.3), 1.7 (95%CI: 1.1-2.4), 1.2 (95%CI: 0.8-1.9), 0.6 (95%CI: 0.3-1.1), 0.2 (95%CI:0.0-0.7), 0.5 (95%CI: 0.1-1.4) for each year from 2010 to 2015 respectively. Conclusion: Although the incidence rate of HIV remains high among IDUs in Dehong, there was a declining trend over the period studied.

Predictive role of RRM1 and BRCA1 mRNA expression on the clinical outcome of advanced non-small cell lung cancer

This study aimed to evaluate the association between RRM1 and BRCA1 expressions and the therapeutic efficacy of platinum-based chemotherapy in non-small cell lung cancer patients in terms of their response and prognosis. In total, 377 patients agreed to participate in our study, and all of them received platinum-based combination chemotherapy between January 2008 and January 2009. The relative cDNA quantitation for RRM1 and BRCA1 was conducted using a fluorescence-based, real-time detection method, using β-actin as a reference gene. The average age of the 377 patients was 64.6 years (range: 25.5-86.4 years), including 269 men and 108 women. Patients with high RRM1 expression benefited more from a platinum-containing regimen, and patients with high BRCA1 expression showed a high response rate to a platinum-containing regimen and reduced disease progression. Patients with high RRM1 expression were associated with a longer progression-free survival (PFS) and overall survival (OS) than those with low expression, and the hazard ratios (HRs) (95% confidence interval (CI)) were 0.67 (0.32-0.91) and 0.54 (0.30-0.95), respectively. Patients with high BRCA1 expression showed longer PFS and OS compared to those with low expression, and the HRs (95%CI) were 0.54 (0.30-0.95) and 0.62 (0.32-0.93), respectively. These results could be used in personalized chemotherapy decisions and to increase the response rate and prolonged survival, and could encourage exploration of the predictive value of other genes.

Effects of polymorphisms in the XRCC1, XRCC3, and XPG genes on clinical outcomes of platinum-based chemotherapy for treatment of non-small cell lung cancer

This study aimed to investigate the effects of single-nucleotide polymorphisms (SNPs) XRCC1 Arg194Trp, XRCC1 Arg280His, XRCC1 Arg399Gln, XRCC3 Thr241Met, XPG His104Asp, and XPG His46His in genes involved in the DNA-repair pathway on the outcomes of platinum-based chemotherapy in patients with advanced non-small cell lung cancer (NSCLC). The study period was from January 2005 to January 2006, and 378 NSCLC patients were enrolled within 1 month after being diagnosed with NSCLC. Genomic DNA was extracted using the Qiagen Blood Kit. Polymerase chain reaction combined with a restriction fragment length polymorphism assay was used for genotyping. Individuals with the XRCC1 399A/A genotype had a higher probability of responding well to platinum-based chemotherapy, indicated by an odds ratio (OR) of 2.27 [95% confidence interval (CI)=1.64-6.97]. Similarly, the XPG T/T genotype was significantly associated with improved responses to chemotherapy, indicated by an OR of 1.90 (95%CI=1.10-3.28). The XRCC1 399A/A genotype was significantly associated with longer disease-free survival and overall survival, indicated by hazard ratios (HRs) of 0.48 (95%CI=0.25-0.88) and 0.51 (95%CI=0.26- 0.98), respectively. Moreover, the XPG 46T/T genotype increased the likelihood of longer disease-free survival and overall survival of NSCLC patients treated with platinum-based chemotherapy (HR=0.47; 95%CI=0.22-0.82 and HR=0.52; 95%CI=0.31- 0.96, respectively). These results indicate that XRCC1 Arg399Gln and XPG His46His might significantly affect the clinical outcomes of platinum-based chemotherapy, highlighting the need for larger studies to confirm the role of these two SNPs in outcomes of NSCLC treatments.

Takayasu arteritis: imaging spectrum at multidetector CT angiography

Takayasu arteritis is a chronic, idiopathic, inflammatory disease that primarily affects large vessels, such as the aorta and its major branches and the pulmonary and coronary arteries. The non-specific inflammation of involved vessels usually leads to concentric wall thickening, fibrosis and thrombus formation. Diseased arteries become stenotic or occluded, undergo vascular remodelling or develop aneurysms. According to the involvement of arteries, six types of Takayasu arteritis are documented. The purpose of this pictorial review is to illustrate the various multidetector CT angiography appearances of Takayasu arteritis and to discuss the differential diagnosis.

Generating quasi-single-cycle relativistic laser pulses by laser-foil interaction

A scheme for producing nearly single-cycle relativistic laser pulses is proposed. When a laser pulse interacts with an overdense thin foil, because of self-consistent nonlinear modulation, the latter will be more transparent to the more intense part of the laser, so that a transmitted pulse can be much shorter than the incident pulse. Using two-dimensional particle-in-cell simulation and analytical modeling, it is found that a transmitted pulse of duration 4 fs and peak intensity 3 x 10{20} W/cm{2} can be generated from a circularly polarized laser pulse. The intensity of the resulting pulse is only limited by that of the incident pulse, since this scheme involves only laser-plasma interaction.

Effects of a dried Bacillus subtilis culture on egg quality

The effects of a dried Bacillus subtilis culture on the egg qualities of layers were studied. Nine hundred and sixty 25-wk-old Lohmann Brown layers were randomly divided into 5 groups with 192 layers in each group. Layers in group 1 were fed a control diet. The remaining groups received the control diet that contained either 20 mg of zinc bacitracin/kg and 4 mg of colistin sulfate/kg or 500, 1,000, or 1,500 mg of B. subtilis culture/ kg, respectively. The results showed improvements in egg production, feed consumption, and feed conversion (P < 0.05) of layers when 500 mg of B. subtilis culture/kg was added to the diets. The results also showed some special improvements in this group, including increases in eggshell thickness, yolk color, and Haugh unit, and decreases in yolk cholesterol concentration (P < 0.05). However, excessive doses of B. subtilis culture did not improve the performance of layers.

Male accessory gland derived factors can stimulate oogenesis and enhance oviposition in Helicoverpa armigera (Lepidoptera: Noctuidae)

In Helicoverpa armigera, female moths began to lay eggs on the third day after emergence. Mating stimulated earlier egg maturation/oogenesis (P = 0.002) and oviposition (P << 0.01). We established a suitable bioassay model for the influence of male accessory glands (MAG) on the physiology of virgin females: Crude extracts of MAG (2- to 3-day-old) were injected into 2-day-old virgin females, and the injected females were dissected 20 h after mating. It was shown that crude extracts of MAG stimulated earlier egg maturation (P < 0.001) and oviposition (the oviposition ratio was more than 2 times the ratio of the control). Proteinaceous components in crude extracts purified by fractionation and sub-fractionation in reverse phase high performance liquid chromatography also stimulated earlier egg maturation (P < 0.01) and ovipositon (more than 2 times the ratio of the control), and we called them the oogenesis and ovipostion factors (OOSF). With SDS-PAGE, the molecular mass of the bands from OOSF was estimated to be between 55-66 KD. Arch.

Effect of nitric oxide on electric and mechanical activities of gastric antral circular muscles in guinea pigs

AIM

To study the effect of exogenous nitric oxide (NO) on electric and mechanical activities of gastric antral circular muscle in guinea pigs in vitro.

METHODS

Mechanical and electric activities of gastric antral circular muscle in guinea pigs were recorded simultaneously.

RESULTS

Sodium nitroprusside (SNP, 0.5 mumol.L-1), an NO donor, inhibited the frequency and amplitude of fast wave and spontaneous contraction of the strips (P < 0.01). SNP-induced inhibition was not blocked by tetrodotoxin, atropine, phentolamine, and propranolol (P > 0.05), but diminished by methylene blue (P < 0.01) and oxyhemoglobin (P < 0.01).

CONCLUSION

Exogenous NO inhibits gastric antral myoelectric and mechanical activities in guinea pigs. The inhibitions are produced by NO acting on extracellular membrane and enhancing the level of cGMP.

[Quantitative analysis of soporific sedative drugs and local anesthetic drugs with unidentical standard substance by GC-AED]

According to the principle of GC-AED (gas chromatography-atomic emission detector), the possibility of quantitative determination of samples by different substances as internal standard was studied. The element C was determined at wavelength of 496 nm. The relative response factors of 17 soporific sedative and local anesthetic drugs were analyzed with an internal standard of proadifen hydrochloride under optimized analytical conditions. Oven temp.: 45 degrees C (0.5 min)-35 degrees C.min-1--120 degrees C-15 degrees C.min-1--220 degrees C-5 degrees C.min-1--250 degrees C; Cool on column injector temp: 60 degrees C-50 degrees C.min-1--250 degrees C (0.2 min); inject volume: 1 microliter; column head pressure: 145 kPa. The results show that the element C(496) in identical or unidentical substances has similar relative response factor. The RSD is 10.21%, which means that a sample can be quantitatively determined by a different substance when the analysis condition and the selected internal standard are suitable. An amobarbital sample of 109.0 micrograms.ml-1 was quantitatively determined by using methylphenobarbitone, pramoxine, lidocaine and itself as internal standard. The results are 117.6, 115.6, 110.0 and 102.14 micrograms.ml-1, respectively. They can be quantitatively determined by each other.

[Effect of inhibition of expression PCNA with ribozyme on the proliferation of HeLa cells]

The Proliferating Cell Nuclear Antigen (PCNA), which is an auxiliary protein for DNA polymerase delta, is found to be essential for cellular DNA replication. A designed hammerhead ribozyme, with high efficiency to cleave the PCNA mRNA site-specificly in vitro, was constructed into a self-trimming expression plasmid, and then was introduced into HeLa cells by lipofectin reagent. Small molecular RNAs, isolated from total cellular RNA with the same length as active ribozyme, can cleave the target RNA in vitro, which suggested that this expression plasmid can yield active ribozyme molecules in cells. In comparison with the vector control, the entrance of S phase of the HeLa cells transfected by the ribozyme expression plasmid was delayed 8 hours after serum stimulation. Mean-while, those cells transfected by mutant inactive ribozyme as antisense RNA control was delayed only 3 hours. These results demonstrated that this ribozyme can inhibit the DNA replication in HeLa cells effectively and could be used as a potential tool to study the function of PCNA in cellular DNA replication and cell cycle progression.

[Clinical research of compound salviae miltiorrhizae injection for severe pancreatitis]

Compound salviae miltiorrhizae injection was administered after operation for 28 cases of severe pancreatitis, and 13 cases were taken as a control group. The results showed that: (1) the difference was not obvious in the morbidity of complications between the two groups, but the mortality (3.6%) of the trial group was significantly lower than that (30.8%) of the control group (P < 0.05); (2) Hematocrit was clearly decreased from 46.1 +/- 5.2% to 33.2 +/- 3.9% in the trial one (P < 0.05), but platelet and hemoglobin showed no statistical significance. It is concluded that compound salviae miltiorrhiza injection might improve hemorheologic abnormalities of the disease, promote the recovery of the pancreatic tissue, and correct the serious complications such as adult respiratory distress syndrome etc.