[SRSF2 promotes glioblastoma cell proliferation by inducing alternative splicing of FSP1 and inhibiting ferroptosis]

Objective: To investigate the effect of serine/arginine-rich splicing factor 2 (SRSF2) on ferroptosis and its possible mechanism in glioblastoma cells. Methods: The online database of gene expression profiling interactive analysis 2 (GEPIA 2) and Chinese Glioma Genome Atlas were used to analyze the expression of SRSF2 in glioblastoma tissue and its association with patients prognosis. To validate the findings of the online databases, the pathological sections of glioblastoma and non-tumor brain tissues from Tianjin Medical University General Hospital, Tianjin, China were collected and analyzed by using immunohistochemistry. Silencing SRSF2 gene expression in glioblastoma cells by siRNA was analyzed with Western blot. The proliferation index was detected by using CCK8 assay. The rescued experiment was conducted by using expression plasmid of pcDNA3.1(+)-SRSF2. The activity of ferroptosis was assessed by using the levels of iron ions and malondialdehyde in glioblastoma cells and the changes in the ratio of glutathione to oxidized glutathione. The changes of gene expression and differential pre-mRNA alternative splicing (PMAS) induced by SRSF2 were monitored by using the third-generation sequencing technology analysis, namely Oxford nanopore technologies (ONT) sequencing analysis. Results: SRSF2 expression was higher in glioblastoma tissues than non-tumor brain tissues. Immunohistochemistry also showed a positive rate of 88.48%±4.60% in glioblastoma tissue which was much higher than the 9.97%±4.57% in non-tumor brain tissue. The expression of SRSF2 was inversely correlated with overall and disease-free disease survivals (P<0.01). The proliferation index of glioblastoma cells was significantly reduced by silencing with SRSF2 siRNA (P<0.01) and could be reversed with transfection of exogenous SRSF2. The levels of intracellulariron ions and malondialdehyde increased (P<0.05), but the glutathione/oxidized glutathione ratio and the expression of key proteins in the glutathione pathway remained unchanged (P>0.05). ONT sequencing results showed that silencing SRSF2 in glioblastoma cells could induce a significant alternative 3' splice site change on ferroptosis suppressor protein 1 (FSP1). Conclusion: SRSF2 inhibits the ferroptosis in glioblastoma cells and promotes their proliferation, which may be achieved by regulating FSP1 PMAS.

Intracellular presence of Helicobacter pylori antigen and genes within gastric and vaginal Candida

BACKGROUND

Helicobacter pylori infections are generally acquired during childhood and affect half of the global population, but its transmission route remains unclear. It is reported that H. pylori can be internalized into Candida, but more evidence is needed for the internalization of H. pylori in human gastrointestinal Candida and vaginal Candida.

METHODS

Candida was isolated from vaginal discharge and gastric mucosa biopsies. We PCR-amplified and sequenced H. pylori-specific genes from Candida genomic DNA. Using optical and immunofluorescence microscopy, we identified and observed bacteria-like bodies (BLBs) in Candida isolates and subcultures. Intracellular H. pylori antigen were detected by immunofluorescence using Fluorescein isothiocyanate (FITC)-labeled anti-H. pylori IgG antibodies. Urease activity in H. pylori internalized by Candida was detected by inoculating with urea-based Sabouraud dextrose agar, which changed the agar color from yellow to pink, indicating urease activity.

RESULTS

A total of 59 vaginal Candida and two gastric Candida strains were isolated from vaginal discharge and gastric mucosa. Twenty-three isolates were positive for H. pylori 16S rDNA, 12 were positive for cagA and 21 were positive for ureA. The BLBs could be observed in Candida cells, which were positive for H. pylori 16S rDNA, and were viable determined by the LIVE/DEAD BacLight Bacterial Viability kit. Fluorescein isothiocyanate (FITC)-conjugated antibodies could be reacted specifically with H. pylori antigen inside Candida cells by immunofluorescence. Finally, H. pylori-positive Candida remained positive for H. pylori 16S rDNA even after ten subcultures. Urease activity of H. pylori internalized by Candida was positive.

CONCLUSION

In the form of BLBs, H. pylori can internalize into gastric Candida and even vaginal Candida, which might have great significance in its transmission and pathogenicity.

Intracellular presence and genetic relationship of Helicobacter pylori within neonates' fecal yeasts and their mothers' vaginal yeasts

Helicobacter pylori are transmissible from person to person and among family members. Mother-to-child transmission is the main intrafamilial route of H. pylori transmission. However, how it transmits from mother to child is still being determined. Vaginal yeast often transmits to neonates during delivery. Therefore, H. pylori hosted in yeast might follow the same transmission route. This study aimed to detect intracellular H. pylori in vaginal and fecal yeasts isolates and explore the role of yeast in H. pylori transmission. Yeast was isolated from the mothers' vaginal discharge and neonates' feces and identified by internal transcribed spacer (ITS) sequencing. H. pylori 16S rRNA and antigen were detected in yeast isolates by polymerase chain reaction and direct immunofluorescence assay. Genetic relationships of Candida strains isolated from seven mothers and their corresponding neonates were determined by random amplified polymorphic DNA (RAPD) fingerprinting and ITS alignment. The Candida isolates from four mother-neonate pairs had identical RAPD patterns and highly homologous ITS sequences. The current study showed H. pylori could be sheltered within yeast colonizing the vagina, and fecal yeast from neonates is genetically related to the vaginal yeast from their mothers. Thus, vaginal yeast presents a potential reservoir of H. pylori and plays a vital role in the transmission from mother to neonate.

[Population structure of food-borne Staphylococcus aureus in China]

Objective: To understand the population structure of food-borne Staphylococcus (S.) aureus in China. Methods: Whole genome sequencing was used to analyze 763 food-borne S. aureus strains from 16 provinces in China from 2006 to 2020. Multilocus sequence typing (MLST), staphylococcal protein A gene (spa) typing, and staphylococcal chromosome cassettemec (SCCmec) typing were conducted, and minimum spanning tree based on ST types (STs) was constructed by BioNumerics 7.5 software. Thirty-one S. aureus strains isolated from imported food products were also included in constructing the genome phylogenetic tree. Results: A total of 90 STs (20 novel types) and 160 spa types were detected in the 763 S. aureus isolates. The 72 STs (72/90, 80.0%) were related to 22 clone complexes. The predominant clone complexes were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, accounting for 82.44% (629/763) of the total. The STs and spa types in the predominant clone complexes changed over the years. The methicillin-resistant S. aureus (MRSA) detection rate was 7.60%, and 7 SCCmec types were identified. The ST59-t437-Ⅳa (17.24%, 10/58), ST239-t030-Ⅲ (12.07%, 7/58), ST59-t437-Ⅴb (8.62%, 5/58), ST338-t437-Ⅴb (6.90%, 4/58) and ST338-t441-Ⅴb (6.90%, 4/58) were the main types in MRSA strains. The genome phylogenetic tree had two clades, and the strains with the same CC, ST, and spa types clustered together. All CC7 methicillin sensitive S. aureus strains were included in Clade1, while 21 clone complexes and all MRSA strains were in Clade2. The MRSA strains clustered according to the SCCmec and STs. The strains from imported food products in CC398, CC7, CC30, CC12, and CC188 had far distances from Chinese strains in the tree. Conclusions: In this study, the predominant clone complexes of food-borne strains were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, which overlapped with the previously reported clone complexes of hospital and community-associated strains in China, suggesting that close attention needs to be paid to food, a vehicle of pathogen transmission in community and food poisoning.

[Study of the urban-impact on microbial communities and their virulence factors and antibiotic resistance genomes in the Nandu River, Haikou]

Objective: To explore the changes in bacterial community structure, antibiotic resistance genome, and pathogen virulence genome in river water before and after the river flowing through Haikou City and their transmission and dispersal patterns and to reveal anthropogenic disturbance's effects on microorganisms and resistance genes in the aquatic environment. Methods: The Nandu River was divided into three study areas: the front, middle and rear sections from the upstream before it flowed through Haikou City to the estuary. Three sampling sites were selected in each area, and six copies of the sample were collected in parallel at each site and mixed for 3 L per sample. Microbial community structure, antibiotic resistance, virulence factors, and mobile genetic elements were analyzed through bioinformatic data obtained by metagenomic sequencing and full-length sequencing of 16S rRNA genes. Variations in the distribution of bacterial communities between samples and correlation of transmission patterns were analyzed by principal co-ordinates analysis, procrustes analysis, and Mantel test. Results: As the river flowed through Haikou City, microbes' alpha diversity gradually decreased. Among them, Proteobacteria dominates in the bacterial community in the front, middle, and rear sections, and the relative abundance of Proteobacteria in the middle and rear sections was higher than that in the front segment. The diversity and abundance of antibiotic resistance genes, virulence factors, and mobile genetic elements were all at low levels in the front section and all increased significantly after flow through Haikou City. At the same time, horizontal transmission mediated by mobile genetic elements played a more significant role in the spread of antibiotic-resistance genes and virulence factors. Conclusions: Urbanization significantly impacts river bacteria and the resistance genes, virulence factors, and mobile genetic elements they carry. The Nandu River in Haikou flows through the city, receiving antibiotic-resistant and pathogen-associated bacteria excreted by the population. In contrast, antibiotic-resistant genes and virulence factors are enriched in bacteria, which indicates a threat to environmental health and public health. Comparison of river microbiomes and antibiotic resistance genomes before and after flow through cities is a valuable early warning indicator for monitoring the spread of antibiotic resistance.

A New EBS2b-IBS2b Base Paring (A-8/T-8) Improved the Gene-Targeting Efficiency of Thermotargetron in Escherichia coli

Thermophilic group II intron is one type of retrotransposon composed of intron RNA and intron-encoded protein (IEP), which can be utilized in gene targeting by harnessing their novel ribozyme-based DNA integration mechanism termed "retrohoming." It is mediated by a ribonucleoprotein (RNP) complex that contains the excised intron lariat RNA and an IEP with reverse transcriptase (RT) activity. The RNP recognizes targeting sites by exon-binding sequences 2 (EBS2)/intron-binding sequences 2 (IBS2), EBS1/IBS1, and EBS3/IBS3 bases pairing. Previously, we developed the TeI3c/4c intron as a thermophilic gene targeting system-Thermotargetron (TMT). However, we found that the targeting efficiency of TMT varies significantly at different targeting sites, which leads to a relatively low success rate. To further improve the success rate and gene-targeting efficiency of TMT, we constructed a Random Gene-targeting Plasmids Pool (RGPP) to analyze the sequence recognition preference of TMT. A new base pairing, located at the -8 site between EBS2/IBS2 and EBS1/IBS1 (named EBS2b-IBS2b), increased the success rate (2.45- to 5.07-fold) and significantly improved gene-targeting efficiency of TMT. A computer algorithm (TMT 1.0), based on the newly discovered sequence recognition roles, was also developed to facilitate the design of TMT gene-targeting primers. The present work could essentially expand the practicalities of TMT in the genome engineering of heat-tolerance mesophilic and thermophilic bacteria. IMPORTANCE The randomized base pairing in the interval of IBS2 and IBS1 of Tel3c/4c intron (-8 and -7 sites) in Thermotargetron (TMT) results in a low success rate and gene-targeting efficiency in bacteria. In the present work, we constructed a randomized gene-targeting plasmids pool (RGPP) to study whether there is a base preference in target sequences. Among all the successful "retrohoming" targets, we found that a new EBS2b-IBS2b base paring (A-8/T-8) significantly increased TMT's gene-targeting efficiency, and the concept is also applicable to other gene targets in redesigned gene-targeting plasmids pool in E. coli. The improved TMT is a promising tool for the genetic engineering of bacteria and could promote metabolic engineering and synthetic biology research in valuable microbes that recalcitrance for genetic manipulation.

[Group Ⅱ introns and the application in biotechnology: a review]

Group Ⅱ introns are self-splicing ribozymes, which insert directly into target sites in DNA with high frequency through "retrohoming". They specifically and efficiently recognize and splice DNA target sites, endowing themselves with great potential in genetic engineering. This paper reviewed the gene targeting principle of group Ⅱ introns and the application in microbial genetic modification, and then analyzed the limitations of them in multi-functional gene editing and eukaryotes based on the "retrohoming" characteristics and the dependence on high Mg²⁺ concentration. Finally, we dissected the potential of group Ⅱ introns in the development of novel gene editing tools based on our previous research outcome and the structural characteristics of the introns, hoping to provide a reference for the application of group Ⅱ introns in biotechnology.

The role of alternative oxidase in plant hypersensitive response

The innate immune system of plants is crucial in defining the fate of a plant cell during plant-pathogen interactions. This response is often accompanied by a hypersensitive reaction leading to the death of a plant cell and restricted pathogen growth. Plant mitochondria, in this case, play a key role by maintaining a balance between cell respiration and reactive oxygen species formation. One of the key features of the hypersensitive response is the shift of the normal plant respiratory pathway to a special 'alternative' pathway. Plants contain an enzyme, alternative oxidase, for maintaining metabolic homeostasis of the cell. This energy dissipating respiration provides a branch in normal respiration by using ubiquinone to form water and heat, thus maintaining the energy status of the cell. Alternative oxidase is thought to minimize production of reactive oxygen species and can also function in 'anti-apoptotic' machinery in plant cells. In this mini review, we briefly describe the alternative respiratory pathway and explain the role of alternative oxidase in important cellular processes, such as programmed cell death and the hypersensitive response.

Effect of different glucogenic to lipogenic nutrient ratios on rumen fermentation and bacterial community in vitro

Aims

This study was to investigate the effect of different ratios of glucogenic to lipogenic nutrients on rumen fermentation and the corresponding ruminal bacterial communities.

Methods and Results

Four diets, including glucogenic diet (G), lipogenic diet (L), two mixed diets: GL1 (G: L = 2 : 1) and GL2 (G:L = 1 : 2), served as substrates and were incubated with rumen fluid in vitro. The results revealed that the gas production, dry matter digestibility and propionate proportion were significantly increased by the G diet than others. The G diet increased the bacterial genera of Succinivibrionaceae_UCG_002, Succinivibrio, Selenomonas_1 and Ruminobacter but decreased some cellulolytic bacteria including the Eubacterium and several genera in family Ruminococcaceae than others.

Conclusions

When the glucogenic nutrient was above 1/3 of the dietary energy source among the four diets, the in vitro incubation had a higher feed digestibility and lower acetate to propionate ratio. Bacterial genera, including Selenomonas, Succinivibrio, Ruminobacter, certain genera in Ruminococcaceae, Christensenellaceae_R‐7_group and Eubacterium, were more sensitive to the glucogenic to lipogenic nutrients ratio.

Significance and Impact of the Study

The present study provides a new perspective about the effect of dietary glucogenic to lipogenic ingredient ratios on rumen metabolism by comparing end‐products, gas production and bacterial composition via an in vitro technique.

AK5, a novel prognosis marker, inhibits apoptosis and promotes autophagy as well as proliferation in human gastric cancer

OBJECTIVE

To explore the relationship between AK5 and gastric cancer.

MATERIALS AND METHODS

The in situ levels of AK5 in the GC tissues from 255 patients were detected by immunohistochemistry (IHC). The correlation between AK5 expression and the clinicopathological parameters was analyzed by Pearson correlation, and the prognostic factors were identified by Cox regression analysis. The transcriptome data of 14 human GC cell lines deposited in the CCLE database were analyzed, and two lines were selected for functional studies. AK5 was knocked down in the AZ521 and MKN74 cells using siRNA, and their proliferation and apoptosis were evaluated by Cell Counting Kit-8 (CCK-8) assay and Annexin-V staining, respectively. In addition, the apoptosis and autophagy of the markers were detected by Western blotting.

RESULTS

Patients expressing high AK5 levels in the tumor tissues had significantly shorter survival compared to low-expressing group. In addition, AK5 expression was associated with T stage and N stage and was an independent prognostic factor. AK5 knockdown in the AZ521 and MKN74 cells significantly inhibited proliferation and autophagy, and increased apoptosis.

CONCLUSIONS

AK5 is a potential prognostic marker and therapeutic target for GC.

The role of cyanide-resistant respiration in Solanum tuberosum L. against high light stress

Cyanide-resistant respiration in potato mitochondria is an important pathway for energy dissipation. It can be activated by high light; however, it is unclear what roles cyanide-resistant respiration plays in the response to high light stress in potato. We designed a CRISPR vector for the functional gene StAOX of the potato cyanide-resistant respiratory pathway. Agrobacterium tumefaciens GV3101 was transformed into potato. Hydrogen peroxide level, MDA content, antioxidant activity and cyanide-resistant respiratory capacity of potato leaves under high light stress were determined. Photosynthetic efficiency and chlorophyll content were determined. In addition, the operation of the malate-oxaloacetate shuttle route and transcription level of photorespiration-related enzymes were also examined. The results showed that two base substitutions occurred at the sequencing target site on leaves of the transformed potato. Accumulation of ROS and increased membrane lipid peroxidation were detected in the transformed potato leaves and lower photosynthetic efficiency was observed. The transcription level of the malate-oxaloacetate shuttle route and photorespiration-related enzymes also significantly increased. These results indicate that the cyanide-resistant respiration is an important physiological pathway in potato in response to high light stress. It also suggests that plant cyanide-resistant respiration is closely related to photosynthesis. This implies the unexplored importance of plant cyanide-resistant respiration in plant photosynthesis, energy conversion and carbon skeleton formation.

Compound climate events transform electrical power shortfall risk in the Pacific Northwest

Power system reliability is sensitive to climate-driven variations in both energy demand and water availability, yet the combined effect of these impacts is rarely evaluated. Here we show that combined climate change impacts on loads and hydropower generation may have a transformative effect on the nature and seasonality of power shortfall risk in the U.S. Pacific Northwest. Under climate change, potential shortfall events occur more readily, but are significantly less severe in nature. A seasonal reversal in shortfall risk occurs: winter shortfalls are eradicated due to reduced building heating demands, while summer shortfalls multiply as increased peak loads for day-time cooling coincide with impaired hydropower generation. Many of these summer shortfalls go unregistered when climate change impacts on loads and hydropower dispatch are analyzed in isolation-highlighting an important role of compound events.

[Prognostic significance of tumor deposits in patients with stage Ⅲ colon cancer]

Objective: To investigate the prognostic significance of tumor deposits (TD) in patients with stage Ⅲ colorectal cancer who underwent radical resection. Methods: We retrospectively analyzed the clinicopathological data, and the impact of tumor deposits on the disease free survival (DFS) and overall survival (OS) in 206 patients with stage Ⅲ colorectal cancer using Kaplan-Meier and Cox regression analyses. Results: Among the 206 patients with stage Ⅲ colorectal cancer, there were 112 (54.4%) tumor deposit-positive (TD⁺ ) cases and 94 (45.6%) tumor deposit-negative (TD^-) cases. The TD^- and TD⁺ cases accounted for 10.6% and 21.4% of patients aged <50 years, 22.3% and 36.6% of patients with poorly differentiated carcinoma, and 16% and 29.5% of patients with neural invasion, respectively (P<0.05 for all). In addition, the neural invasion was more often found along with the increasing number of TD. However, multivariate analysis showed that TD was not significantly associated with DFS and OS of the patients. Among the patients with N1 stage cancer, the 3-year DFS rates of TD⁺ and TD^- groups were 23.0% and 58.8%, and the median disease-free survival durations were 26 months and 43 months, respectively (P=0.002). Meanwhile, in the TD^- group, the 3-year DFS rates in the patients with stage N1a~1b without tumor deposit and N1c cancer were 63.5% and 21.2%, and the median disease-free survival durations were 41 and 25 months, respectively (P=0.004). Conclusions: Tumor deposit is an independent unfavorable prognostic factor affecting the DFS. The number of tumor deposits may be an important factor affecting prognosis in stage Ⅲ colorectal cancer patients. Tumor deposits after radical resection are associated with neural invasion, and can be used as an independent factor of poor prognostic evaluation in patients with stage N1 colorectal cancer.

Expression features of CXCR5 and its ligand, CXCL13 associated with poor prognosis of advanced colorectal cancer

OBJECTIVE

CXCL13 plays a unique role in the trafficking and homing of B1 cells associated with its cognate receptor, CXCR5. The CXCR5-CXCL13 axis has been previously demonstrated to be a poor prognosis factor in malignancies. However, the clinical significance of the CXCR5-CXCL13 expression in colorectal cancer carcinoma (CRC) remains unclear. The aim of this study was to investigate the CXCR5-CXCL13 expression in CRC and determine its correlation with the progression and prognosis of the tumor.

PATIENTS AND METHODS

A total of 144 paraffin-embedded specimens with advanced colon cancer were assessed for CXCR5 and CXCL13 by immunohistochemistry. Patients' long-term survival was also monitored. There were significant differences in lymph node metastasis (p = 0.0066), neural invasion (p = 0.0061) and neural invasion (p = 0.0001) between high and low expression of CXCR5.

RESULTS

There were significant differences in distant metastasis (p = 0.0261), TNM stage (p = 0.0409), differentiation (p < 0.0001) and neural invasion of the CXCL13. Both CXCR5 and CXCL13 was associated with poor correlation with the overall survival (OS) and relapse-free survival (RFS).

CONCLUSIONS

Our data suggest that the CXCR5 and CXCL13 may play a crucial role in the development, metastasis and relapse of advanced colon cancer. They can be used as prognostic markers of colon cancer in clinical practice.

The patterns of care studies for operable breast cancer in China

e11607

Background: To present the results of clinical practices for operable breast cancer (BC) in the developed areas of China during the past decade. Methods: Four academic levels of radiotherapy (RT) departments, located in the Southeast coast of China, were selected. A pattern of care study, about women with operated BC and post-operative RT during 1999 and 2006, was conducted. The recruited samples were evaluated for their medical files completeness at first. For qualified documentations, data collected included patient characteristics, clinical and pathologic features, and treatment course received. Frequencies and corresponding percentages were calculated and analyzed for comparisons between 1999 and 2006. Results: 97 in 1999 and 271 in 2006 were identified as qualified files. Patient's diagnosis median age were 48 (1996) and 46 (2006) years. The clinical staging with I, II, and III (UICC 1997) were in 11%, 69%, 13% of 1999 patients and 15%, 74%, 7% of the 2006. The pathological characteristics were clearly defined in 78% (1999) and 84% (2006), but hormonal receptors and Her2neu were performed in 59% and 0% in the 1999 vs. 73% (p < 0.05) and 1% in 2006 survey. As type and extent of surgery and RT, the percentage of conservative treatment was increased from 4% in 1999 to 12% in 2006 (p< 0.05), postmastectomy RT was done for all the others. The time interval from operation to initiation of RT were longer in 2006, the mean was delayed from 23.8 to 43.4 days. The axillary operation pattern including lymph node dissection, level I/II dissection, and sentinel lymph node biopsy (SLNB), were documented in 61%, 24%, and 8% of patients in 2006. For patients of 1999, no SLNB was performed and 16% with level I/II operation (p< 0.05). Systemic chemotherapy (CT) and/or hormonal therapy were used in 74% (1999) and 98% (2006) of patients respectively (p< 0.05). Anthracyclines and paclitaxel-based CT regimens use significantly increased between 1999 and 2006 (31% vs. 52% and 12% vs. 36%). Conclusions: The practice patterns established in this study provide a baseline data. The present results demonstrate a low level of compliance with Western guidelines of clinical practices with current BC standards and continued improvement in many categories. Establishment and widespread use of international guidelines in China are desirable.

No significant financial relationships to disclose.

[Detection of Plasmodium vivax by polymerase chain reaction in Hainan]

AIM

To establish a modified polymerase chain reaction(PCR) method for the detection of Plasmodium vivax in the endemic areas of malaria and compare the method with the conventional light microscopy in the field.

METHODS

A PCR method was modified by improving the collection procedures of blood samples, template extraction, primer design and optimizing the reaction condition. The method was evaluated by examining blood samples from 310 patients with vivax malaria and compared with the conventional light microscopy in endemic areas of Hainan Province.

RESULTS

The positive rates of the modified PCR method and microscopic method were 34.2% and 31.9%, respectively.

CONCLUSION

The modified PCR method is simple, sensitive and specific for the detection of vivax malaria patients in endemic areas.

Synthesis and evaluation of novel aldose reductase inhibitors: Effects on lens protein kinase Cgamma

PURPOSE

To synthesize novel aldose reductase inhibitors (ARI) that will normalize losses in protein kinase Cgamma (PKCgamma) observed during diabetes and galactosemia.

METHODS

ARI were synthesized as tricyclic pyrones 1-6 (HAR-1 through HAR-6) from 3-methyl-1H,7H-5a,6,8,9-tetrahydro-1-oxopyrano[4,3-b][1]benzopyran and (5aS,7S)-7-isopropenyl-3-methyl-1H,7H-5a,6,8,9-tetrahydro-1-oxopyrano[4,3-b][1]benzopyran and were tested by inhibition of aldose reductase enzyme activity in vitro and by inhibition of polyol formation in lens epithelial cells in culture. Identified compounds were further tested in galactosemic rat lens in vivo for (a) normalized PKCgamma levels by Western blot, (b) reduction of phosphorylation of the gap junction protein Cx46 by analyses of co-immunoprecipitated proteins, and (c) by normalization of gap junction activity as measured by dye transfer.

RESULTS

HAR-1 (1H,7H-5a,6,8,9-tetrahydro-1-oxopyrano[4,3-b][1]benzopyran-3-acetic acid) was identified as an ARI with IC50 for aldose reductase inhibition at 2 nM. Polyol accumulation in lens epithelial cells was reduced by 80% at 10 microM. Rats fed 40% galactose for 9 days had an 80% reduction in PKCgamma levels which were normalized by HAR-1 at 100 mg/kg/day, fed orally. Phosphorylation of Cx46 was increased by 50% and this was normalized in HAR-1 treated rats (6 day treatment). Gap junction activity of galactosemic rats was reduced by 55% and this was normalized by HAR-1 in six day-treated rats.

CONCLUSIONS

HAR-1 is a novel ARI which normalized losses of PKCgamma, changes in Cx46 phosphorylation, and gap junction activity.

P53 germline mutations in childhood cancers and cancer risk for carrier individuals

The family history of cancer in children treated for a solid malignant tumour in the Paediatric Oncology Department at Institute Gustave-Roussy, has been investigated. In order to determine the role of germline p53 mutations in genetic predisposition to childhood cancer, germline p53 mutations were sought in individuals with at least one relative (first- or second-degree relative or first cousin) affected by any cancer before 46 years of age, or affected by multiple cancers. Screening for germline p53 mutation was possible in 268 index cases among individuals fulfilling selection criteria. Seventeen (6.3%) mutations were identified, of which 13 were inherited and four were de novo. Using maximum likelihood methods that incorporate retrospective family data and correct for ascertainment bias, the lifetime risk of cancer for mutation carriers was estimated to be 73% for males and nearly 100% for females with a high risk of breast cancer accounting for the difference. The risk of cancer associated with such mutations is very high and no evidence of low penetrance mutation was found. These mutations are frequently inherited but de novo mutations are not rare.

Impact of delayed reperfusion of myocardial hibernation on myocardial ultrastructure and function and their recoveries after reperfusion in a pig model of myocardial hibernation

This study examined the effect of delayed reperfusion of myocardial hibernation from 24 hours to 7 days on myocardial ultrastructural and functional changes and their recoveries after reperfusion.

BACKGROUND

We have previously shown in pigs that after reperfusion the functional and structural alterations in short-term myocardial hibernation which was reperfused in 24 hours can recover in 7 days. The effect of delayed reperfusion of hibernating myocardium on the extent and severity of cellular and extracellular structural changes of hibernating myocardium, and their recoveries after reperfusion is not known.

METHODS AND RESULTS

A severe LAD stenosis was created in 27 pigs, reducing resting flow by 30-40% immediately after placement of the stenosis and producing acute ischemia as evidenced by regional lactate production, a decrease in regional coronary venous pH, reduced regional wall thickening (from 38.5 +/- 5.1% to 10.4 +/- 8.0%) and a 33% reduction of regional oxygen consumption. The stenosis was maintained either for 24 hours in 9 pigs (group 1) with LAD flow of 0.65 +/- 0.13 ml/min/g (38% reduction), or for 7 days in 17 pigs (group 2) with LAD flow of 0.67 +/- 0.14 ml/min/g (36% reduction). There were no differences (p = NS) in the reduction of wall thickening, rate-pressure product, lactate production, or regional oxygen consumption between group 1 and group 2. Quantitative morphometric evaluation of the ultrastructure on electromicrographs revealed a greater decrease in sarcomere volume and a higher incidence of myocytes with reduced sarcomere volume in 7-day than in 24-hour hibernating regions (53 +/- 19% versus 33 +/- 14%, p < 0.05). Patchy myocardial necrosis with replacement fibrosis was common, but 6 of the 18 pigs had no myocardial necrosis or replacement fibrosis in the 7-day hibernating group, and 4 of 9 pigs had no patchy myocyte necrosis in the 24 hour hibernating group. In 6 pigs in group 1 in which the stenosis was then released and hibernating myocardium reperfused in 24 hours, regional wall thickening recovered to 30 +/- 6% (p = NS compared to baseline) after one week of reperfusion. In 12 pigs in group 2 in which the stenosis was released and hibernating myocardium reperfused in 7 days, regional wall thickening recovered slowly, from 10.1 +/- 7.2% to 18.1 +/- 8.3% at one week (n = 5) and to 28.0 +/- 3.6% at 3-4 weeks of reperfusion (n = 7, p < 0.05 compared to baseline). Similarly, the sarcomere volume or myofilament recovered significantly (p < 0.01) and was not different compared to the normal region (p = NS) in the 24-hour hibernating region of group 1, but the recovery was much slower and was incomplete at 4 weeks (p < 0.01) compared to baseline in the 7-day hibernating region of group 2. Recovery of regional wall thickening correlated with ultrstructural recovery (p < 0.01). By multivariate stepwise regression analysis, the degree of LAD flow reduction, the extent of fibrosis, and myofilament loss were independent predictors of the extent of functional recovery.

CONCLUSIONS

In a porcine model of myocardial hibernation with myocardial hypoperfusion, systolic dysfunction, and metabolic adaptations, a longer period of myocardial hibernation with delayed reperfusion was associated with more severe abnormalities of myocytes. an increasing interstitial fibrosis, and more protracted myofibrillar and functional recoveries after reperfusion. The extent of functional recovery is related to the degree of coronary flow reduction, the severity of the ultrastructural changes, and the extent of interstitial fibrosis.

[Immunophenotype and P-glycoprotein expression in CD7 positive adult acute myeloid leukemia]

OBJECTIVE

To study the immunophenotype and P-glycoprotein expression in CD7 positive adult acute myeloid leukemia (CD7+ AML).

METHODS

Morphology, P-glycoprotein, cytogenetics and immunophenotype were examined in 30 previously untreated CD7+ AML patients.

RESULTS

The CD7 positive rate was 11.4% in 262 AML patients. CD7+ AML patients had a significantly higher incidence of peripheral leukocytosis and blasts and FAB M1 subtype and were associated with CD34 and P-glycoprotein expression. 42.3% of CD7+ AML achieved complete remission with a median remission duration of 4 months, and a median time to CR of 48 days.

CONCLUSION

Patients with CD7+ AML are usually CD34 and P-glycoprotein positive. These patients had a lower CR rate and a shorter remission duration.

[The clinical and biological significance of megakaryocytic antigen expression in acute myeloid leukemia]

OBJECTIVE

To explore megakaryocytic (MK) antigen expression in previously untreated adult acute myeloid leukemia (AML) and its relation to the clinical and biological characteristics.

METHODS

Two hundred and eleven cases of AML were detected with flow cytometric immunofluorescence assay.

RESULTS

Twenty-seven cases (12.8%) were MK antigen positive with the higher positive rates in hybrid acute leukemia (45.5%) and acute monoblastic leukemia (24.1%). MK antigen expression was significantly correlated with CD34 antigen expression, high white cell count, high P-glycoprotein positivity and had no correlation with chromosome aberration. 33.3% of MK positive AML patients achieved complete remission which was significantly lower than that (71.9%) in MK negative cases.

CONCLUSION

MK antigen positive AML might derived from malignant transformation of hemotopoietic stem cell at earlier stage and the detection of MK expression was of values in predicting treatment effect and prognosis for adult AML.

[Prognostic significance of P-glycoprotein expression in acute leukemia in adults]

OBJECTIVE

To explore the prognostic significance of P-glycoprotein (P-gp) expression in previously untreated acute leukemia in adults.

METHODS

P-gp expression in 151 acute myeloblastic leukemia (AML) and 47 acute lymphoblastic leukemia (ALL) was determined by monoclonal antibody UIC2 and flow cytometry.

RESULTS

The rate of complete remission (CR) differed between P-gp+ and P-gp- AML (20.5% vs 78.5%, P < 0.001), but the CR rate did not significantly differ between P-gp+ and P-gp- ALL(66.7% vs 80%, P > 0.05). The six-month relapse rate was significantly higher in P-gp+ group than that of P-gp- group (AML: 66.7% vs 8.7%, P < 0.001; ALL: 50% vs 9.5%, P < 0.05). The median disease-free survival time was shorter in P-gp+ group than in P-gp- group (AML: 5 months vs 13 months; ALL: 4 months vs 13 months).

CONCLUSION

Overexpression of P-gp is a poor prognostic factor in adult acute leukemia and P-gp detection is useful for the prediction of treatment response and early relapse.

Clinical and biological relevance of flow cytometric determination of P-glycoprotein expression in acute non-lymphocytic leukemia

OBJECTIVE

To evaluate the characteristics of P-glycoprotein (P-gp) expression of acute non-lymphocytic leukemia (ANLL) at different status and the prognostic and biological features in ANLL at diagnosis.

METHODS

Monoclonal antibody UIC2 and indirect immunofluorescence assay by flow cytometry were used to determine P-gp expression of 169 patients with ANLL, including 152 previously untreated, 7 refractory and 10 at remission.

RESULTS

P-gp was expressed in 28.9% of the previously untreated ANLL cases and P-gp was lower than that in 71.4% of the refractory cases (P < 0.05). No P-gp expression was found in the patients at remission. For previously untreated AN-LL, P-gp was highly expressed in hybrid acute leukemia (66.7%) and acute monoblastic leukemia (47.4%). P-gp expression was highly associated with surface markers [cluster of differentiation (CD) 34, CD7, CD14, CD42b and CD61] and unfavorable cytogenetic abnormalities. About 23% of P-gp-ANLL obtained complete remission, which was significantly lower than that (76%) in P-gp-cases.

CONCLUSIONS

P-gp expression is higher in refractory ANLL cases than that in cases at diagnosis or at remission. P-gp is an index of poor prognosis in adults with ANLL. P-gp+ ANLL cases have unique clinical and biological characteristics.

[The clinical and biological significance of P-glycoprotein expression in acute nonlymphocytic leukemia]

To evaluate the clinical and biological significance of P-glycoprotein (P-gp) expression in adult acute nonlymphocytic leukemia (ANLL), P-gp was detected in 169 patients including 152 previously untreated cases, 7 refractory cases, and 10 cases at remission by using monoclonal antibody UIC2 and flow cytometry. P-gp was expressed in 29% of previously untreated cases, being less than in 71% of the refractory cases. P-gp expression was not found in patients at remission. Morphologically, P-gp expression was high in hybrid acute leukemia (67%) and acute monoblastic leukemia (47%) subtypes. Immunologically, P-gp expression was significantly associated with CD34, CD7, CD14 or CD42b/CD61. Cytogenetically, P-gp expression was highly associated with poor prognosis abnormalities (54%), which was significantly higher than 7% of P-gp expression in good prognosis abnormalities. 23% of P-gp positive previously untreated ANLL (not including M3) achieved complete remission; this was significantly lower than 76% in P-gp negative cases. These suggested that P-gp expression is an index of poor prognosis in adult ANLL and P-gp positive ANLL has unique clinical and biological features.

Expression of the Renilla reniformis luciferase gene in mammalian cells

A cDNA encoding the Renilla reniformis luciferase was expressed in similan and murine cells in a transient and stable manner, respectively. Light emission catalyzed by luciferase was detected from transfected cells both in vitro and in vivo. This work establishes the Renilla luciferase gene as a new efficient marker of gene expression in mammalian cells.