[Comprehensive undergraduate experiment: synthesis and chromism of 4-[bis(4-methylphenyl)amino] benzaldehyde].

To solve the problems of the lack of property research in organic synthesis experiments and the relative independence of instrumental analytical methods in experiments, we designed a comprehensive undergraduate experiment based on mechanofluorochromic materials. In this project, 4-[bis(4-methylphenyl)amino] benzaldehyde was synthesized via the Vilsmeier-Haack reaction using 4,4'-dimethyltriphenylamine as the raw material. The product was then characterized by mass spectrometry, infrared absorption spectroscopy, and nuclear magnetic resonance spectroscopy. The solvatofluorochromism and mechanofluorochromism of the target material were studied using ultraviolet-visible absorption spectroscopy, fluorescence spectroscopy, etc. Furthermore, the mechanism of mechanofluorochromism was determined using powder X-ray diffraction. Organic synthesis and a series of instrumental analytical methods were combined to form an integrated experiment. The experiment is interesting, scientific, and comprehensive for undergraduates as a creative exercise; moreover, it can inspire their interest in chemical research, cultivate a variety of experimental operation abilities, improve creative-thinking skills, and encourage the development of effective solutions to existing problems in chemical experiments.

Application of a core genome sequence typing (cgMLST) pipeline for surveillance of Clostridioides difficile in China.

Introduction: Clostridioides difficile (C. difficile) is a nosocomial bacterial pathogen that causes antibiotic-associated diarrhea mediated by cellular exotoxins secreted into the intestine during bacterial growth. Multilocus sequence typing (MLST) and PCR ribotyping are the main molecular typing for C. difficile. Whole genome sequencing (WGS) core genome multilocus sequence typing (cgMLST) was developed for genetic evolution and outbreak investigation of C. difficile with higher precision and accuracy. Methods: A total of 699 whole (complete and draft) genome sequences of distinct C. difficile strains were used in this study to identify core gene set (2469 core genes) and the cgMLST scheme for the phylogeny analysis of C. difficile. This cgMLST pipeline was then carried the Chinese Pathogen Identification Net (China PIN) for surveillance of C. difficile in China. Within the China PIN, 195 WGS of C. difficile and an outbreak of CDI with 12 WGS of C. difficile were used to evaluate the cgMLST pipeline. Results: The result displayed that mostly tested C. difficile isolates could be successfully divided into 5 classic clades and the outbreak event was also successfully identified. Discussion: The results are meaningful and offer a practicable pipeline for a national-wide surveillance of C. difficile in China.

A rapid multiplex real-time PCR detection of toxigenic Clostridioides difficile directly from fecal samples.

This study developed a new single-tube multiplex real-time PCR method for detecting toxigenic C. difficile directly from fecal samples using tcdA, tcdB, cdtB, and internal gene tpi as targets, which could be performed on kinds of polymerase chain reaction device including point-of-care testing (POCT), with improved detection efficiency. The specificity, sensitivity, and repeatability of each gene was evaluated using 69 C. difficile isolates and 74 fecal samples. Results were compared with established PCR, qPCR, and ELISA methods. Interspecies specificity was 100% based on six common intestinal pathogens (Escherichia coli, Enterococcus Faecium, Enterococcus faecalis, Clostridium perfringens, Bacteroides fragilis, Clostridium botulinum). The lower detection limit (LDL) for tcdA, tcdB, and cdtB with pure C. difficile DNA was 101,100, and 100 copies/µL, respectively, the coefficients of variation among different experimental batches and within each experimental batch were both less than 3%, which shows that this method has strong repeatability. And the LDL of fecal DNA was 5 × 100, 5 × 103, and 5 × 102 colony-forming units (CFU)/g, respectively. In addition, the efficiency for detection of tcdA was compared with established PCR and real-time PCR methods, demonstrating high consistency (98.4%) and similar sensitivity. ELISA was used to confirm inconsistent results, which were identical with our method. The sensitivity and specificity for detecting toxigenic C. difficile in fecal samples were 96.49% and 94.12% compared with the toxigenic culture (TC). This method effectively identified the toxigenic and non-toxigenic strains with high specificity, sensitivity, and repeatability, and could reduce the false positive rate of tcdA, and accurately identify the typical Asian strain RT017, making it potentially contribute to the surveillance of CDI in China. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-022-03434-6.

A narrative review of Clostridioides difficile infection in China.

Clostridioides difficile is the predominant pathogen responsible for antimicrobial associated diarrhea (AAD) and health care facility-associated infectious diarrhea. The role of C. difficile in China and its impact on public health have gained attention in recent years. Most clinical C. difficile isolates in China belong to multilocus sequence type clade 1 with sequence types (STs) 3, 35 and 54 predominating. Of note, the proportion of C. difficile isolates from clade 4, especially ST37 (PCR ribotype 17), is much higher in China than in other areas. In China, the antimicrobial-resistance profile of C. difficile is similar to that of other countries, demonstrating a higher resistance rate to erythromycin, clindamycin, and fluoroquinolones (ciprofloxacin, levofloxacin, and moxifloxacin). In general, susceptibility to vancomycin and metronidazole of clinical C. difficile in China is high, however, some resistance to metronidazole have recently been reported. Preclinical research on C. difficile in animals in China is limited, and different studies have reported varied isolation rates and antimicrobial resistance profiles. The diverse molecular types of C. difficile in China merit further epidemiological, genomic and evolutionary investigation. While the use of probiotics in preventing C. difficile infection (CDI) have received both support and opposition, the discovery of new probiotics and new formulations are showing promising results in combating the threat posed by CDI.

The molecular characters and antibiotic resistance of Clostridioides difficile from economic animals in China.

BACKGROUND: It has been performed worldwidely to explore the potential of animals that might be a reservoir for community associated human infections of Clostridioides difficile. Several genetically undistinguished PCR ribotypes of C. difficile from animals and human have been reported, illustrating potential transmission of C. difficile between them. Pig and calf were considered as the main origins of C. difficile with predominant RT078 and RT033, respectively. As more investigations involved, great diversity of molecular types from pig and calf were reported in Europe, North American and Australia. However, there were quite limited research on C. difficile isolates from meat animals in China, leading to non-comprehensive understanding of molecular epidemiology of C. difficile in China. RESULTS: A total of 55 C. difficile were isolated from 953 animal stool samples, within which 51 strains were from newborn dairy calf less than 7 days in Shandong Province. These isolates were divided into 3 STs and 6 RTs, of which ST11/RT126 was predominant type, and responsible for majority antibiotic resistance isolates. All the isolates were resistant to at least one tested antibiotics, however, only two multidrug resistant (MDR) isolates were identified. Furthermore, erythromycin (ERY) and clindamycin (CLI) were the two main resistant antibiotics. None of the isolates were resistant to vancomycin (VAN), metronidazole (MTZ), tetracycline (TET), and rifampin (RIF). CONCLUSIONS: In this study, we analyzed the prevalence, molecular characters and antibiotic resistance of C. difficile from calf, sheep, chicken, and pig in China. Some unique features were found here: first, RT126 not RT078 were the dominant type from baby calf, and none isolates were got from pig; second, on the whole, isolates from animals display relative lower resistant rate to these 11 tested antibiotics, compared with isolates from human in China in our previous report. Our study helps to deep understanding the situation of C. difficile from economic animals in China, and to further study the potential transmission of C. difficile between meat animals and human.

Psychophysiological and cognitive effects of strawberry plants on people in isolated environments.

In manned deep-space exploration, extremely isolated environments may adversely affect the mood and cognition of astronauts. Horticultural plants and activities have been proven to be effective in improving their physical, psychological, and cognitive states. To assess the effects of applying horticultural plants and activities in isolated environments, this study investigated the influence of viewing strawberry plants on the mood of people in a laboratory experiment as indicated by heart rate, salivary cortisol, and psychological scales. The results showed that heart rate and salivary cortisol were significantly decreased after viewing strawberry plants for 15 min. "Tension" and "confusion" scored using the Profile of Mood States negative mood subscales, and anxiety levels measured using the State-Trait Anxiety Inventory scale were also significantly reduced. This study further explored the impact of viewing strawberry plants on cognition. A notable reduction of the subjects' reaction time after 15-min plant viewing was observed. Based on these findings, a long-duration isolated experiment in a bioregenerative life support system-"Lunar Palace I"-was conducted. A similar trend was obtained that crew members' mood states were improved by viewing the strawberry plants, but no significant change was observed. This study provided some experimental evidence for the benefits of interacting with strawberry plants in isolated environments.

Microevolution within ST11 group Clostridioides difficile isolates through mobile genetic elements based on complete genome sequencing.

BACKGROUND: Clade 5 Clostridioides difficile diverges significantly from the other clades and is therefore, attracting increasing attention due its great heterogeneity. In this study, we used third-generation sequencing techniques to sequence the complete whole genomes of three ST11 C. difficile isolates, RT078 and another two new ribotypes (RTs), obtained from three independent hospitalized elderly patients undergoing antibiotics treatment. Mobile genetic elements (MGEs), antibiotic-resistance, drug resistance genes, and virulent-related genes were analyzed and compared within these three isolates. RESULTS: Isolates 10,010 and 12,038 carried a distinct deletion in tcdA compared with isolate 21,062. Furthermore, all three isolates had identical deletions and point-mutations in tcdC, which was once thought to be a unique characteristic of RT078. Isolate 21,062 (RT078) had a unique plasmid, different numbers of transposons and genetic organization, and harboring special CRISPR spacers. All three isolates retained high-level sensitivity to 11 drugs and isolate 21,062 (RT078) carried distinct drug-resistance genes and loss of numerous flagellum-related genes. CONCLUSIONS: We concluded that capillary electrophoresis based PCR-ribotyping is important for confirming RT078. Furthermore, RT078 isolates displayed specific MGEs, indicating an independent evolutionary process. In the further study, we could testify these findings with more RT078 isolates of divergent origins.

Antibiotic resistance of clinical isolates of Clostridioides difficile in China and its association with geographical regions and patient age.

It is known that antibiotic usage is associated with the development of Clostridioides difficile infection (CDI), especially clindamycin, third-generation cephalosporins, and fuoroquinolones. Antibiotic resistance rates to many antibiotics varies a lot by study. We performed a study focused on antibiotic resistance in clinical isolates of C. difficile from more widespread geographic regions across China. Of 319 C. difficile isolates tested against 11 antibiotics, 313 (98.1%) were resistant to at least one antibiotic. The highest rate of resistance was to ciprofloxacin, clindamycin, and erythromycin across all age groups, similar to previous studies. However, all isolates were susceptible to metronidazole and vancomycin. Overall the resistance rate to tested antibiotics was lower than other reports in China except for chloramphenicol and meropenem. Genotype ST37/RT017 in clade 4 was resistant to more antibiotics than other types. Unexpectedly, RT078 isolates in this study were susceptible to almost all tested antibiotics. In addition, the proportion of multi-drug resistant (MDR) isolates observed (17%) in this study was much lower than several European studies (up to 55%) and a previous study in China (78%). Although isolates from patients aged between 65 and 85 were more resistant to antibiotics in comparison to other age groups, MDR isolates were still detected in children below 2-years of age. The highest percentage of MDR isolates was determined in South China, an area that is most developed economically. The clade 4, RT017 (ST37) has been associated with outbreaks in Europe and North America and is responsible for most C. difficile infections (CDIs) in Asia. In addition, RT017 is often clindamycin and fluoroquinolone resistant. This study provided a relatively comprehensive description of antibiotic resistance of C. difficile in China, and further elucidates the epidemiology and antibiotic resistance of clinical isolates of C. difficile in China at a national level.

Independent Microevolution Mediated by Mobile Genetic Elements of Individual Clostridium difficile Isolates from Clade 4 Revealed by Whole-Genome Sequencing.

Horizontal gene transfer of mobile genetic elements (MGEs) accounts for the mosaic genome of Clostridium difficile, leading to acquisition of new phenotypes, including drug resistance and reconstruction of the genomes. MGEs were analyzed according to the whole-genome sequences of 37 C. difficile isolates with a variety of sequence types (STs) within clade 4 from China. Great diversity was found in each transposon even within isolates with the same ST. Two novel transposons were identified in isolates ZR9 and ZR18, of which approximately one third to half of the genes showed heterogenous origins compared with the usual intestinal bacterial genes. Most importantly, catD, known to be harbored by Tn4453a/b, was replaced by aac(6') aph(2'') in isolates 2, 7, and 28. This phenomenon illustrated the frequent occurrence of gene exchanges between C. difficile and other enterobacteria with individual heterogeneity. Numerous prophages and CRISPR arrays were identified in C. difficile isolates of clade 4. Approximately 20% of spacers were located in prophage-carried CRISPR arrays, providing a new method for typing and tracing the origins of closely related isolates, as well as in-depth studies of the mechanism underlying genome remodeling. The rates of drug resistance were obviously higher than those reported previously around the world, although all isolates retained high sensitivity to vancomycin and metronidazole. The increasing number of C. difficile isolates resistant to all antibiotics tested here suggests the ease with which resistance is acquired in vivo. This study gives insights into the genetic mechanism of microevolution within clade 4. IMPORTANCE Mobile genetic elements play a key role in the continuing evolution of Clostridium difficile, resulting in the emergence of new phenotypes for individual isolates. On the basis of whole-genome sequencing analysis, we comprehensively explored transposons, CRISPR, prophage, and genetic sites for drug resistance within clade 4 C. difficile isolates with different sequence types. Great diversity in MGEs and a high rate of multidrug resistance were found within this clade, including new transposons, Tn4453a/b with aac(6') aph(2'') instead of catD, and a relatively high rate of prophage-carried CRISPR arrays. These findings provide important new insights into the mechanism of genome remodeling within clade 4 and offer a new method for typing and tracing the origins of closely related isolates.

Polymorphism analysis of virulence-related genes among Candida tropicalis isolates.

BACKGROUND: Adhesion, biofilm formation, yeast-hyphal transition, secretion of enzymes, and hemolytic activity are all considered important factors in Candida tropicalis infection. However, DNA sequence data for this pathogen are limited. In this study, the polymorphism and heterogeneity of genes agglutinin-like sequences (ALS)2, Lipase (LIP)1, LIP4, and secretory aspartyl proteinase tropicalis (SAPT)1-4 as well as the relationship between phenotype and genotype were analyzed. METHODS: This study started in August 2013, and ended in July 2017. The complete length of ALS2, LIP1, LIP4, and SAPT1-4 of 68 clinical C. tropicalis isolates was sequenced. Single nucleotide polymorphisms (SNPs) as well as insertions and deletions (indels) were identified within these genes. In addition, phenotypic characteristics of the virulent factors, including adhesion and the secretion of aspartyl proteinases and phospholipases, were determined. RESULTS: There were 73, 24, 17, 16, 13, and 180 SNPs in the genes LIP1, LIP4, SAPT1, SAPT2, SAPT3, and SAPT4, respectively. Furthermore, 209 SNPs were identified in total for the gene ALS2. Interestingly, large fragment deletions and insertions were also found in ALS2. Isolate FXCT 01 obtained from blood had deletions on all 4 sites and showed the lowest adhesion ability on the polymethylpentene surface. In addition, isolates with deletions in the regions 1697 to 1925 and 2073 to 2272 bp displayed relatively low abilities for adhesion and biofilm formation, and this phenotype correlated with the deletions found in ALS2. LIP1, SAPT4, and ALS2 displayed great heterogeneity among the isolates. Large deletions found in gene ALS2 appeared to be associated with the low ability of adhesion and biofilm formation of C. tropicalis. CONCLUSION: This study might be useful for deeper explorations of gene function and studying the virulent mechanisms of C. tropicalis.

Molecular Characterization of Clostridium difficile Isolates in China From 2010 to 2015.

Clostridium difficile infection (CDI) has become a worldwide public health problem causing high mortality and a large disease burden. Molecular typing and analysis is important for surveillance and infection control of CDI. However, molecular characterization of C. difficile across China is extremely rare. Here, we report on the toxin profiles, molecular subtyping with multilocus sequence typing (MLST) and PCR ribotyping, and epidemiological characteristics of 199 C. difficile isolates collected between 2010 through 2015 from 13 participating centers across China. We identified 35 STs and 27 ribotypes (RTs) among the 199 C. difficile isolates: ST35 (15.58%), ST3 (15.08%), ST37 (12.06%), and RT017 (14.07%), RT001 (12.06%), RT012 (11.56%) are the most prevalent. One isolate with ST1 and 8 isolates with ST 11 were identified. We identified a new ST in this study, denoted ST332. The toxin profile tcdA+tcdB+tcdC+tcdR+tcdE+CDT- (65.83%) was the predominant profile. Furthermore, 11 isolates with positive binary toxin genes were discovered. According to the PCR ribotyping, one isolate with RT 027, and 6 isolates with RT 078 were confirmed. The epidemiological characteristics of C. difficile in China shows geographical differences, and both the toxin profile and molecular types exhibit great diversity across the different areas.

Clinical significance of costimulatory molecules CD40/CD40L and CD134/CD134L in coronary heart disease: A case-control study.

The aim of the study was to evaluate the potential role of CD40/CD40 ligand (CD40L) and CD134/CD134 ligand (CD134L) in the development of coronary heart disease (CHD) via the performance of a case-control study.The research objects were 234 cases of CHD patients and 120 cases of well-matched normal controls. Following the separation of peripheral blood mononuclear cells (PBMCs), real-time quantitative PCR (qRT-PCR), Western blot, immunohistochemistry, and flow cytometry were applied for the detection of mRNA levels and expression levels of CD40/CD40L and CD134/CD134L; meanwhile, intercellular adhesion molecule-1 (ICAM-1) and Fas protein mRNA levels were detected using qRT-PCR.There was no statistical difference in the comparison of baseline characteristics between groups, indicating comparability between groups. qRT-PCR and Western blot analysis indicated that CD40/CD40L and CD134/CD134L mRNA and protein expression levels were all increased in the CHD group than those in the control group. Flow cytometry further confirmed the similar tendency. Meanwhile, ICAM-1 and Fas protein mRNA levels were elevated in the CHD group and positively correlated with the above parameters. Furthermore, CD40/CD40L expression rates were negatively correlated with gender and different types of CHD. Meanwhile, CD134/CD134L expressions were also higher in male patients, in patients with family history, previous history of hypertension, diabetes, and cerebrovascular diseases.CD40/CD40L and CD134/CD134L are increased and may have potential correlation with clinical pathological features of patients with CHD. Further in-depth exploration of costimulatory molecules for CHD guidance as well as intrinsic mechanisms are needed combined with in vivo and in vitro experiments.

[Effects of partial revascularization in elderly patients over 80 years old with coronary artery diseases].

OBJECTIVE: To observe the clinical effects of partial revascularization on elderly patients with coronary artery diseases(CAD) METHODS: Percutaneous coronary interventions (PCI) of the most likely culprit vessels were performed in 37 patients over 80 years old with multivessel coronary artery diseases (CAD). RESULTS: The success rate of PCI was 100% in these elderly patients without serious complications. The in-hospital mortality rate was 2.7%, and all the other patients recovered and were discharged. CONCLUSION: Partial revascularization for elderly CAD patients can achieve satisfactory clinical results, and close attention should be given to the heart and kidney function of these patients.

[Multi-central randomized controlled trials of electroacupunture at Zhigou (TE 6) for treatment of constipation induced by stagnation or deficiency of qi].

OBJECTIVE: To assess the therapeutic effect and safety of electroacupuncture (EA) at Zhigou (TE 6) on constipation induced by stagnation or deficiency of qi. METHODS: Multi-central randomized controlled trials were adopted and the patients conforming to the criteria for diagnosis, enrolling and excluding were divided into an observation group and a control group according to random number table. The observation group were treated with EA at Zhigou (TE 6) and the control group with EA at non-acupoint for 4 weeks. The cumulative score of clinical symptoms, colon transmission test and various safety indexes were assessed. The following-up was carried out 1 and 3 months after the end of treatment. RESULTS: EA at Zhigou (TE 6) could obviously improve clinical symptoms and colon transmission time, decrease using rate of Kaisailu and cathartics, with an effective rate of 94.4%, which was better than 61.3% in the control group (P < 0.0001). CONCLUSION: EA at Zhigou (TE 6) has a function of regulating qi and relaxing the bowels and it is an effective method for treatment of constipation with safety and no adverse effect.

[Unusual expression and molecular mechanisms of E-cadherin, beta-catenin in correlation with clinicopathologic parameters in neuroblastoma].

OBJECTIVE: To study the expression of E-cadherin and beta-catenin in neuroblastomas of various degrees of differentiation, and to investigate their molecular mechanisms in correlation with clinicopathologic parameters. METHODS: Immunohistochemistry EnVision method was used to detect E-cadherin and beta-catenin expression in 90 paraffin-embedded tissue samples of neuroblastomas. The methylation status of CpG islands of E-cadherin promoter was investigated by MSP in 7 fresh tissue and 24 paraffin-embedded tissue samples. The mutation status of exon 3 of beta-catenin gene was studied by PCR in 7 fresh tissue samples. Statistical analysis of the data was performed by SPSS software. RESULTS: E-cadherin and beta-catenin were abnormally expressed in neuroblastomas in general. The expression of beta-catenin in well-differentiated neuroblastoms was markedly higher (47/70, 67.1%) than that of the poorly differentiated tumors (8/20, 40.0%). There was a markedly decreased expression of both genes in tumors with lymph node metastasis than those without. Demethylation was seen in some regions of the promoter of E-cadherin in 31 cases of nuroblatomas. PCR of the exon 3 of beta-catenin followed by DNA sequencing demonstrated rearrangements and mutations in 7 cases, including 2 cases harboring identical point mutation at gene position 27184, leading to a T-->A alteration. CONCLUSIONS: The abnormal over-expression of E-cadherin in neuroblastomas is independent of the methylation status of their promoter sequences. The abnormal expression of beta-catenin may be related to mutational changes at exon 3 of the gene.

[Spatial expression of cardiac alpha-actin during heart development in embryos].

OBJECTIVE: Conotruncal defects (CTD) is a common type of cyanotic congenital heart defects. It was shown that CTD might be produced by ablation of cardiac neural crest during early stage embryos in experimental studies. There were many kinds of genes involved and cardiac alpha-actin (CAA) was one of them. The purpose of this study was to investigate the spatial expression of CAA gene during embryonic heart development, and to explore its role in the pathogenesis of congenital heart defects. METHODS: Experimental chicken embryos were subjected to cardiac neural crest ablation by using electric stimulation at 36-40 hr incubation stage. The embryos and organs of experimental and normal control groups during different developing periods were taken out, RNA was extracted by Trizol, and then reverse transcription was done. The dynamic changes of CAA mRNA expression at different development stages of embryos were assayed by fluorescent real-time PCR. The embryos and tissues at different stages were taken out, and paraffin sections were made. The localizations of CAA antibody expression in the developmental embryos were detected by immunohistochemical analysis (peroxidase-DAB coloration). RESULTS: (1) The expression of CAA gene was detected at early embryo development, and increased subsequently to a stable level. Its expression was mainly limited to heart site, and could be increased along with the maturation of the cardiac muscle. There was no expression or little trace expression in liver, brain, and stomach. (2) There was a significantly low level of CAA gene expression on days 2-7 of chicken embryos whose cardiac neural crest were ablated in comparison with normal controls (P = 0.013). The level of CAA gene expression was also down-regulated on days 7, 9 and 15 of embryonic cardiac tissues (P = 0.029). CONCLUSION: CAA gene is closely associated with heart development, its expression was adjusted by cardiac neural crest, and its dysfunction may be an important factor leading to congenital heart defects.

A new immortalized rat cell line, hepatic stellate cell-PQ, exhibiting characteristics of hepatic stellate cell.

BACKGROUND: Playing a central role in hepatic fibrosis, hepatic stellate cell (HSC) has made itself the major target of research. The limited supply of HSC, however, can not meet the ever growing need of experiment. Establishment and identification of novel immortalized HSC line thus may be urgently required. METHODS: Primary HSCs were isolated from a normal adult male Sprague-Dawley rat by in situ perfusion with collagenase IV and pronase E, and then were purified by single-step density gradient centrifugation with nycodenz. Once they reached total activation in culture, a new immortalized myofibroblast-like HSC line was established through cellular cloning. Its characteristics were identified by means of immunocytochemical staining, light microscopy, transmission electron microscopy, and growth curve analysis. RESULTS: The novel HSC line, termed HSC-PQ, had a doubling time of about 75 hours in the Dulbecco's modified Eagle medium (DMEM) containing 20% fetal bovine serum. Most of the main morphological characteristics of the differentiated primary HSC could be detected in HSC-PQ cell, while functional features of activated HSC such as alpha-smooth muscle actin, desmin, collagen type I, collagen type III, fibronectin, laminin and other extracellular matrix proteins could also be found in it except for collagen type IV. In contrast, fat droplets and autofluorescence of vitamin A disappeared in the HSC-PQ line. This cell line had been maintained in culture for over 30 passages and more than 1 year with little alternation in biological characteristics. CONCLUSION: A new rat HSC line (HSC-PQ) has been successfully established. It consistently retains the characteristics of activated primary HSC, and has proved to be immortalized.

Assessment of regional myocardial blood flow with myocardial contrast echocardiography: an experimental study.

OBJECTIVES: The aim of this study was to verify the accuracy of using myocardial contrast echocardiography (MCE), to quantify regional myocardial blood flow (MBF), and to evaluate myocardial viability in comparison to that measured by radiolabeled microsphere and pathologic examination. METHODS: Epicardial MCE was obtained in five myocardial ischemic dogs with constant microbubble intravenous infusion. After the video intensity (VI, y) versus pulsing interval plots derived from each myocardial pixel were fitted to an exponential function: y = A(1 - e(-beta t)), the MBF was calculated as the product of A (microvascular cross-sectional area or myocardial blood volume) and beta (mean myocardial microbubble velocity). The MBF was also obtained by radiolabeled microsphere method. RESULTS: The MBF derived by radiolabeled microsphere method in the normal, ischemic, and infarcted region was 1.5 +/- 0.3, 0.7 +/- 0.3, and 0.3 +/- 0.2 ml/min per gram, respectively; P < 0.01. The product of A and beta in those regions was 52.5 +/- 15.1, 24.4 +/- 3.9, and 3.7 +/- 3.8, respectively; P < 0.01. The normalized product of A and beta correlated well with normalized MBF (r = 0.81, P = 0.001). CONCLUSION: Our initial study demonstrated that MCE has an ability to assess MBF in ischemic myocardium in the experimental model. It may provide a potential capability to detect viable myocardium noninvasively after total persistent coronary occlusion in the clinical setting.