mTOR-dependent loss of PON1 secretion and antiphospholipid autoantibody production underlie autoimmunity-mediated cirrhosis in transaldolase deficiency

Transaldolase deficiency predisposes to chronic liver disease progressing from cirrhosis to hepatocellular carcinoma (HCC). Transition from cirrhosis to hepatocarcinogenesis depends on mitochondrial oxidative stress, as controlled by cytosolic aldose metabolism through the pentose phosphate pathway (PPP). Progression to HCC is critically dependent on NADPH depletion and polyol buildup by aldose reductase (AR), while this enzyme protects from carbon trapping in the PPP and growth restriction in TAL deficiency. Although AR inactivation blocked susceptibility to hepatocarcinogenesis, it enhanced growth restriction, carbon trapping in the non-oxidative branch of the PPP and failed to reverse the depletion of glucose 6-phosphate (G6P) and liver cirrhosis. Here, we show that inactivation of the TAL-AR axis results in metabolic stress characterized by reduced mitophagy, enhanced overall autophagy, activation of the mechanistic target of rapamycin (mTOR), diminished glycosylation and secretion of paraoxonase 1 (PON1), production of antiphospholipid autoantibodies (aPL), loss of CD161+ NK cells, and expansion of CD38+ Ito cells, which are responsive to treatment with rapamycin in vivo. The present study thus identifies glycosylation and secretion of PON1 and aPL production as mTOR-dependent regulatory checkpoints of autoimmunity underlying liver cirrhosis in TAL deficiency.

SP1-induced lncRNA DUBR promotes stemness and oxaliplatin resistance of hepatocellular carcinoma via E2F1-CIP2A feedback

Oxaliplatin-based chemotherapy is widely used to treat advanced hepatocellular carcinoma (HCC), but many patients develop drug resistance that leads to tumor recurrence. Cancer stem cells (CSCs) are known to contribute to chemoresistance, the underlying mechanism, however, remains largely unknown. In this study, we discovered a specificity protein 1 (SP1)-induced long noncoding RNA--DPPA2 upstream binding RNA (DUBR) and its high expression in HCC tissues and liver CSCs. DUBR was associated with HCC progression and poor chemotherapy response. Moreover, DUBR facilitated the stemness and oxaliplatin resistance of HCC in vitro and in vivo. Mechanistically, DUBR upregulated cancerous inhibitor of protein phosphatase 2A (CIP2A) expression through E2F1-mediated transcription regulation. DUBR also exerted function by binding microRNA (miR)-520d-5p as a competing endogenous RNA to upregulate CIP2A at mRNA level. CIP2A, in turn, stabilized E2F1 protein and activated the Notch1 signaling pathway, thereby increasing the stemness feature of HCC and leading to chemoresistance. In conclusion, we identified SP1/DUBR/E2F1-CIP2A as a critical axis to activate the Notch1 signaling pathway and promote stemness and chemoresistance of HCC. Therefore, DUBR could be a potential target in HCC treatment.

Analysis of mutation status and homologous recombination deficiency in tumors of patients with germline BRCA1 or BRCA2 mutations and metastatic breast cancer: OlympiAD

BACKGROUND

Presence of a germline BRCA1 and/or BRCA2 mutation (gBRCAm) may sensitize tumors to poly(ADP-ribose) polymerase (PARP) inhibition via inactivation of the second allele, resulting in gene-specific loss of heterozygosity (gsLOH) and homologous recombination deficiency (HRD). Here we explore whether tissue sample testing provides an additional route to germline testing to inform treatment selection for PARP inhibition.

PATIENTS AND METHODS

In this prespecified exploratory analysis, BRCA1 and/or BRCA2 mutations in blood samples (gBRCAm) and tumor tissue (tBRCAm) were analyzed from patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer and known gBRCAm, enrolled in the phase III OlympiAD trial. The frequency and nature of tBRCAm, HRD score status [HRD-positive (score ≥42) versus HRD-negative (score <42) using the Myriad myChoice® CDx test] and rates of gsLOH were determined, and their impact on clinical efficacy (objective response rate and progression-free survival) was explored.

RESULTS

Tissue samples from 161/302 patients yielded tBRCAm, HRD and gsLOH data for 143 (47%), 129 (43%) and 125 (41%) patients, respectively. Concordance between gBRCAm and tBRCAm was 99%. gsLOH was observed in 118/125 (94%) patients [BRCA1m, 73/76 (96%); BRCA2m, 45/49 (92%)]. A second mutation event was recorded for two of the three BRCA1m patients without gsLOH. The incidence of HRD-negative was 16% (21/129) and was more common for BRCA2m (versus BRCA1m) and/or for hormone receptor-positive (versus triple-negative) disease. Olaparib antitumor activity was observed irrespective of HRD score.

CONCLUSIONS

gBRCAm identified in patients with HER2-negative metastatic breast cancer by germline testing in blood was also identified by tumor tissue testing. gsLOH was common, indicating a high rate of biallelic inactivation in metastatic breast cancer. Olaparib activity was seen regardless of gsLOH status or HRD score. Thus, additional tumor testing to inform PARP inhibitor treatment selection may not be supported for these patients.

Tongxin formula protects H9c2 cardiomyocytes from cobalt chloride-induced hypoxic injury via inhibition of apoptosis

In this study, the effect of the Tongxin formula (TXF) on the apoptosis of H9c2 cardiomyocytes induced by cobalt chloride (CoCl₂) was investigated, and the potential mechanism was explored. A hypoxic injury model of H9c2 cardiomyocytes was established using CoCl₂. The cell viability was measured using a Cell Counting Kit-8 assay. The lactate dehydrogenase (LDH) release and caspase-3 activity were measured using spectrophotometry. The apoptosis was measured via Annexin V-FITC/PI staining and flow cytometry. The changes in the mitochondrial membrane potential were examined using immunofluorescence microscopy following the loading of JC-1 probes. The expressions of apoptosis-related proteins and key proteins in the phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) pathway were examined via immunoblotting. The different TXF concentrations studied significantly improved the percentage of viability of cardiomyocytes with hypoxic injury, and the LDH release, apoptotic rate, caspase-3 activity, and levels of cleaved caspase-3 protein were reduced in the injured cells. Additionally, the TXF group had increased mitochondrial membrane potential, upregulated expression of Bcl-2 and p-Akt proteins, and significantly reduced expression of cleaved caspase-3 protein in the cells with hypoxic injury. Moreover, in the TXF group, the treatment significantly reduced the BAX protein expression, but the difference was not statistically significant compared with the CoCl2 group. In this study, TXF regulated the expression of apoptosis-related proteins, inhibited apoptosis, increased the mitochondrial membrane potential, and alleviated damage to the mitochondrial membrane, thereby protecting the cardiomyocytes from hypoxic injury. The underlying mechanism could be related to activation of the PI3K/Akt signaling pathway and upregulation of the Bcl-2 protein.

Androgen deprivation-induced elevated nuclear SIRT1 promotes prostate tumor cell survival by reactivation of AR signaling

The NAD⁺-dependent deacetylase, Sirtuin 1 (SIRT1) is involved in prostate cancer pathogenesis. However, the actual contribution is unclear as some reports propose a protective role while others suggest it is harmful. We provide evidence for a contextual role for SIRT1 in prostate cancer. Our data show that (i) mice orthotopically implanted with SIRT1-silenced LNCaP cells produced smaller tumors; (ii) SIRT1 suppression mimicked AR inhibitory effects in hormone responsive LNCaP cells; and (iii) caused significant reduction in gene signatures associated with E2F and MYC targets in AR-null PC-3 and E2F and mTORC1 signaling in castrate-resistant ARv7 positive 22Rv1 cells. Our findings further show increased nuclear SIRT1 (nSIRT1) protein under androgen-depleted relative to androgen-replete conditions in prostate cancer cell lines. Silencing SIRT1 resulted in decreased recruitment of AR to PSA enhancer selectively under androgen-deprivation conditions. Prostate cancer outcome data show that patients with higher levels of nSIRT1 progress to advanced disease relative to patients with low nSIRT1 levels. Collectively, we demonstrate that lowering SIRT1 levels potentially provides new avenues to effectively prevent prostate cancer recurrence.

Technical validation of a new microfluidic device for enrichment of CTCs from large volumes of blood by using buffy coats to mimic diagnostic leukapheresis products

Diagnostic leukapheresis (DLA) enables to sample larger blood volumes and increases the detection of circulating tumor cells (CTC) significantly. Nevertheless, the high excess of white blood cells (WBC) of DLA products remains a major challenge for further downstream CTC enrichment and detection. To address this problem, we tested the performance of two label-free CTC technologies for processing DLA products. For the testing purposes, we established ficollized buffy coats (BC) with a WBC composition similar to patient-derived DLA products. The mimicking-DLA samples (with up to 400 × 106 WBCs) were spiked with three different tumor cell lines and processed with two versions of a spiral microfluidic chip for label-free CTC enrichment: the commercially available ClearCell FR1 biochip and a customized DLA biochip based on a similar enrichment principle, but designed for higher throughput of cells. While the samples processed with FR1 chip displayed with increasing cell load significantly higher WBC backgrounds and decreasing cell recovery, the recovery rates of the customized DLA chip were stable, even if challenged with up to 400 × 106 WBCs (corresponding to around 120 mL peripheral blood or 10% of a DLA product). These results indicate that the further up-scalable DLA biochip has potential to process complete DLA products from 2.5 L of peripheral blood in an affordable way to enable high-volume CTC-based liquid biopsies.

Single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle: a novel technique for pediatric inguinal hernia

PURPOSE

Laparoscopic high ligation of the internal inguinal ring is an alternative procedure for treatment of pediatric inguinal hernia (PIH), with a major trend toward increasing use of extracorporeal knotting and decreasing use of working ports. We have utilized this laparoscopic technique to treat the entire spectrum of PIH (including incarcerated cases) for more than 17 years, and the technique continues to evolve and improve. We herein report our latest modification of this minimally invasive technique, namely single-site laparoscopic percutaneous extraperitoneal closure (SLPEC) of hernia sac high ligation using an ordinary taper needle, and evaluate its safety and efficacy.

METHODS

From July 2016 to July 2019, 790 children with indirect PIH were treated by laparoscopic surgery. All patients underwent high ligation surgery with a modified single-site laparoscopic technique mainly performed by extracorporeal suturing with an ordinary closed-eye taper needle (1/2 arc 11 × 34). The clinical data were retrospectively analyzed.

RESULTS

All surgeries were successful without serious complications. A contralateral patent processus vaginalis (CPPV) was found intraoperatively and subsequently repaired in 190 patients (25.4%). The mean operative time was 15 min (8-25 min) for 557 unilateral hernias and 21 min (14-36 min) for 233 bilateral hernias. The mean postoperative stay was 20 h. Minor complications occurred in five patients (0.63%) and were managed properly, with no major impact on the final outcomes. No recurrence was noted in the patients who were followed up for 6-42 months. No obvious scar was present postoperatively.

CONCLUSION

Modified SLPEC of hernia sac high ligation using an ordinary taper needle for repair of indirect PIH is a safe, reliable, and minimally invasive procedure with satisfactory outcome, with no special device being needed. It is easy to learn and perform and is worthy of popularization in the clinical setting.

RAD51 foci as a functional biomarker of homologous recombination repair and PARP inhibitor resistance in germline BRCA-mutated breast cancer

Background

BRCA1 and BRCA2 (BRCA1/2)-deficient tumors display impaired homologous recombination repair (HRR) and enhanced sensitivity to DNA damaging agents or to poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi). Their efficacy in germline BRCA1/2 (gBRCA1/2)-mutated metastatic breast cancers has been recently confirmed in clinical trials. Numerous mechanisms of PARPi resistance have been described, whose clinical relevance in gBRCA-mutated breast cancer is unknown. This highlights the need to identify functional biomarkers to better predict PARPi sensitivity.

Patients and methods

We investigated the in vivo mechanisms of PARPi resistance in gBRCA1 patient-derived tumor xenografts (PDXs) exhibiting differential response to PARPi. Analysis included exome sequencing and immunostaining of DNA damage response proteins to functionally evaluate HRR. Findings were validated in a retrospective sample set from gBRCA1/2-cancer patients treated with PARPi.

Results

RAD51 nuclear foci, a surrogate marker of HRR functionality, were the only common feature in PDX and patient samples with primary or acquired PARPi resistance. Consistently, low RAD51 was associated with objective response to PARPi. Evaluation of the RAD51 biomarker in untreated tumors was feasible due to endogenous DNA damage. In PARPi-resistant gBRCA1 PDXs, genetic analysis found no in-frame secondary mutations, but BRCA1 hypomorphic proteins in 60% of the models, TP53BP1-loss in 20% and RAD51-amplification in one sample, none mutually exclusive. Conversely, one of three PARPi-resistant gBRCA2 tumors displayed BRCA2 restoration by exome sequencing. In PDXs, PARPi resistance could be reverted upon combination of a PARPi with an ataxia-telangiectasia mutated (ATM) inhibitor.

Conclusion

Detection of RAD51 foci in gBRCA tumors correlates with PARPi resistance regardless of the underlying mechanism restoring HRR function. This is a promising biomarker to be used in the clinic to better select patients for PARPi therapy. Our study also supports the clinical development of PARPi combinations such as those with ATM inhibitors.

Thyroid abnormalities following the use of cytotoxic T-lymphocyte antigen-4 and programmed death receptor protein-1 inhibitors in the treatment of melanoma

CONTEXT

Checkpoint inhibitors are emerging as important cancer therapies but are associated with a high rate of immune side effects, including endocrinopathy.

OBJECTIVE

To determine the burden of thyroid dysfunction in patients with melanoma treated with immune checkpoint inhibitors and describe the clinical course.

DESIGN AND PATIENTS

Consecutive patients with melanoma treated with either ipilimumab, nivolumab, pembrolizumab or the combination of ipilimumab and nivolumab were identified. Baseline thyroid function tests were used to exclude those with pre-existing thyroid abnormalities, and thyroid function tests during treatment used to identify those with thyroid dysfunction.

RESULTS

Rates of overt thyroid dysfunction were in keeping with the published phase 3 trials. Hypothyroidism occurred in 13·0% treated with a programmed death receptor-1 (PD-1) inhibitor and 22·2% with a combination of PD-1 inhibitor and ipilimumab. Transient subclinical hyperthyroidism was observed in 13·0% treated with a PD-1 inhibitor, 15·9% following a PD-1 inhibitor, and 22·2% following combination treatment with investigations suggesting a thyroiditic mechanism rather than Graves' disease, and a high frequency of subsequent hypothyroidism. Any thyroid abnormality occurred in 23·0% following ipilimumab, 39·1% following a PD-1 inhibitor and 50% following combination treatment. Abnormal thyroid function was more common in female patients.

CONCLUSION

Thyroid dysfunction occurs commonly in patients with melanoma treated with immune checkpoint inhibitors, with rates, including subclinical dysfunction, occurring in up to 50%.

Validation of daily increment deposition and early growth of mud carp Cirrhinus molitorella

In this study, laboratory reared Cirrhinus molitorella from hatching through to the juvenile stage were used to validate daily increment deposition. Lapilli were suitable for ageing C. molitorella. The slope of the linear relationships between increment counts and age was not significantly different from 1 (n = 258, P > 0·05), indicating that growth increments are deposited daily. The first increment following the first-feeding check formed 3 days post hatch (dph). One hundred and twenty-three juveniles, ranging from 36·4 to 84·7 mm in body length (L_B ), were collected in the Pear River estuary from July to January in both 2014 and 2015 and used to estimate growth rate. The core in the lapillus, consisting of a single primordium, a diffuse area and the first-feeding band, was followed by 20 narrow and poorly contrasted daily increments. Thereafter, increments were wide and well-defined, and, finally became less distinct, but still homogenous after c. 53 dph. The mean increment width increased to the 29th increment and stayed relatively constant up to the 35th increment and then, gradually declined to the edge of the otolith. Wild juveniles were aged from 69 to 178 dph and hatched from the 15 February to 2 September. Growth rate was estimated from the adjusted linear regression of L_B on age: L_B = 4·37 + 0·44A (r² = 0·60), where A = age. The radius of the core and the regularity and resolution of the increments showed some differences between reared and wild fish. These results are of value for the further study of early life traits and recruitment of C. molitorella.

Study on female breast cancer imaging screening consultation network in Guangdong Province, China

OBJECTIVE

This study aimed to construct breast cancer image screening consultation network (BISCN) that connects all levels of medical institutions in Guangdong Province.

MATERIALS AND METHODS

Fourteen hospitals in different cities and counties (districts) of Guang-dong were selected for breast cancer screening with imaging (breast X-ray, ultrasound, and MRI). "Breast Imaging Reporting and Data System (BI-RADS)" was taken as reference to build up image data base of breast cancer screening and BISCN that is an internet-based network platform. BISCN quality control was performed to improve the diagnostic accuracy and collaboration of members. In 2011, the BISCN members underwent breast imaging diagnosis training and conducted a questionnaire survey.

RESULTS

BISCN allowed quick, synchronous, and accurate communication and feedback of diagnostic imaging in breast cancer among all levels of medical institutions and improved the ability of breast cancer screening in the province, as well as the detection rate of early breast cancer throughout the province, especially in the grassroot units. The survey results showed that the trainees' understanding situation of the training contents before training was 2.02 ± 1.75 points. Through the study, the participants considered that the teaching contents could solve the daily diagnose problems (2.91 ± 0.70 points), the post-training scores were improved (2.88 ± 1.23 points), and highly satisfactory with the teaching contents (2.81 ± 0.53 points). All students passed the examination and were qualified for the future.

CONCLUSIONS

BISCN is of good feasibility in construction and applicability in management by raising diagnosis level of breast cancer in Guangdong Province.

Proliferation inhibition and CD4/CD8 thymocyte subset skewing by in vivo exposure of C57BL/6 mice to Ah receptor-binding 3,3',4,4'-tetrachlorobiphenyl

3,3',4,4'-Tetrachlorobiphenyl (TCB) and other Ah receptor-binding xenobiotics lead to thymus atrophy and immunosuppression, the former possibly causing the latter. In order to better understand the TCB-induced events in the murine thymus, we analyzed the effects of TCB on the proliferation capacity and maturation kinetics of different thymocyte subsets in 2-week-old C57BL/6 mice (i.e. of the Ahb-1 'dioxin-sensitive' genotype). Mice were injected with a single dose of TCB, and the development of thymocytes was followed up for 10 days using flow cytometric surface marker analysis combined with measurement of DNA content by 7-amino-actinomycin D staining. Already 2 days after exposure to TCB, fewer of the more immature thymocytes (CD4-CD8-, CD4-CD8+ alpha beta TCR-) were proliferating than in thymi from control animals. Eventually this led to a severe decrease in thymus cellularity. Moreover, a shift towards the CD4-CD8+ mature subpopulation was observed. The effects were reversible, and proliferation and CD4/CD8 subset distribution returned to normal levels within the observation period. The results are in good agreement with the data obtained previously in vitro with fetal thymus organ cultures.

A region of barley chromosome 6H harbors multiple major genes associated with net type net blotch resistance

Net type net blotch (NTNB), caused by Pyrenophora teres f. teres Drechs., is prevalent in barley growing regions worldwide. A population of 118 doubled haploid (DH) lines developed from a cross between barley cultivars 'Rika' and 'Kombar' were used to evaluate resistance to NTNB due to their differential reaction to various isolates of P. teres f. teres. Rika was resistant to P. teres f. teres isolate 15A and susceptible to isolate 6A. Conversely, Kombar was resistant to 6A, but susceptible to 15A. A progeny isolate of a 15A x 6A cross identified as 15A x 6A#4 was virulent on both parental lines. The Rika/Kombar (RK) DH population was evaluated for disease reactions to the three isolates. Isolate 15A induced a resistant:susceptible ratio of 78:40 (R:S) whereas isolate 6A induced a resistant:susceptible ratio of 40:78. All but two lines had opposite disease reactions indicating two major resistance genes linked in repulsion. Progeny isolate 15A x 6A#4 showed a resistant:susceptible ratio of 1:117 with the one resistant line also being the single line that was resistant to both 15A and 6A. An RK F(2) population segregated in a 1:3 (R:S) ratio for both 15A and 6A indicating that resistance is recessive. Molecular markers were used to identify a region on chromosome 6H that harbors the two NTNB resistance genes. This work shows that multiple NTNB resistance genes exist at the locus on chromosome 6H, and the recombinant DH line harboring the resistance alleles from both parents will be useful for the development of NTNB-resistant barley germplasm.

Chromosomal microarray mapping suggests a role for BSX and Neurogranin in neurocognitive and behavioral defects in the 11q terminal deletion disorder (Jacobsen syndrome)

We performed a prospective analysis on 14 11q- patients to determine the relationship between the degree of cognitive impairment and relative deletion size. Seventeen measures of cognitive function were assessed. All nine patients with a deletion of at least 12.1 Mb had severe global cognitive impairment, with full-scale IQ <50, whereas all five patients with smaller deletions, <or=11.8 Mb, demonstrated mild cognitive impairment, with a full-scale IQ of 63 or higher (p < 0.001). Among these five patients, the two patients with the larger deletions (11.4, 11.8 Mb) had a selective impairment in freedom from distractability compared to the three patients with smaller deletions (<or=9.1 Mb). We propose the presence of a proximal critical region that contains a gene for global cognitive function and a distal critical region that contains a gene essential for auditory attention, which may be necessary for optimizing intellectual function. The proximal critical region is 300 kb and contains three annotated genes. One of these genes, BSX, encodes a brain-specific homeobox protein that in gene-targeted mice has been shown previously to have a role in regulating locomotory behavior via BSX-expressing neurons in the hypothalamus. The distal critical region, approximately 2.2 Mb, contains 18 annotated genes. One gene in this region, Neurogranin, has been demonstrated previously in mice to be critical for synapse plasticity and long-term potentiation. Taken together, our results implicate the presence of at least two loci in distal 11q that when deleted, cause global and selective deficits in neurocognitive function. These findings have important implications for genetic counseling and potential gene-specific therapies.

In vitro and in vivo evidence for lack of endovascular remodeling by third trimester trophoblasts

The placental-decidual interaction through invading trophoblasts determines whether a physiological transformation of the uterine spiral arteries is established or not. Trophoblast-orchestrated artery remodeling is central to normal placentation. Dysregulated uteroplacental interaction and vascular remodeling are thought to be associated with the molecular events underlying the pathology of late pregnancy anomalies including preeclampsia. Although the exact gestational age at which trophoblast invasion ceases is not known, it remains unclear whether late pregnancy trophoblasts retain the ability to transform the uterine arteries. Here, we have developed a dual cell, in vitro culture system that mimics the vascular remodeling events during normal pregnancy. We demonstrate that first and third trimester trophoblasts respond differentially to interactive signals from endothelial cells when cultured on matrigel. Term primary trophoblasts or immortalized third trimester extravillous TCL1 trophoblasts not only fail to respond to signals from endothelial cells but also inhibit endothelial cell tube formation. In contrast, HTR8 cells, representing a first trimester trophoblast cell line with invasive properties, undergo spontaneous migration and synchronize with the endothelial cells in a capillary network. This disparity in behavior was confirmed in vivo using a matrigel plug assay. Poor expression of VEGF C and VEGF receptors coupled with high E-cadherin expression by term primary trophoblasts and TCL1 cells contributed to their restricted interactive and migratory properties. We further show that the kinase activity of VEGF R2 is essential for proactive crosstalk by HTR8 cells. This unique behavior of first trimester trophoblasts in the presence of endothelial cells offers a potential approach to study cell-cell interactions and to decipher modulatory components in the serum samples from adverse pregnancy outcomes.

FAP mutations destabilize transthyretin facilitating conformational changes required for amyloid formation

Functional transthyretin (TTR) can be transformed into amyloid by partial acid denaturation yielding a monomeric amyloidogenic intermediate which self-associates. The amyloidogenic intermediate has substantial beta-sheet structure with non-native but defined tertiary structure. pH-dependent proteolysis sensitivity studies have identified portions of TTR which become disordered and solvent-exposed in the amyloidogenic intermediate. These include the C-strand-loop D-strand portion of TTR which moves away from the core of the beta-sandwich fold. Mutations that are associated with early onset-amyloid disease (familial amyloidotic polyneuropathy; FAP) function by destabilizing tetrameric TTR in favour of the monomeric amyloidogenic intermediate which has a rearranged C-strand-loop D-strand region. In most cases the FAP mutations do not significantly alter the native folded structure, but instead act on the denaturation pathway by a mechanism that is not completely understood. Interestingly, mutations have also been characterized which strongly stabilize tetrameric TTR and make amyloid formation very difficult at pHs accessible in vivo.

Identification and chromosomal location of major genes for resistance to Pyrenophora teres in a doubled-haploid barley population

Net blotch, caused by Pyrenophora teres, is one of the most economically important diseases of barley worldwide. Here, we used a barley doubled-haploid population derived from the lines SM89010 and Q21861 to identify major quantitative trait loci (QTLs) associated with seedling resistance to P. teres f. teres (net-type net blotch (NTNB)) and P. teres f. maculata (spot-type net blotch (STNB)). A map consisting of simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers was used to identify chromosome locations of resistance loci. Major QTLs for NTNB and STNB resistance were located on chromosomes 6H and 4H, respectively. The 6H locus (NTNB) accounted for as much as 89% of the disease variation, whereas the 4H locus (STNB resistance) accounted for 64%. The markers closely linked to the resistance gene loci will be useful for marker-assisted selection.

Identification and mapping of SNPs from ESTs in sunflower

More than 67,000 expressed sequence tags (ESTs) have recently been generated for sunflower (Helianthus), including 44,000 from cultivated confectionery (RHA280) and oilseed (RHA801) lines of Helianthus annuus and 23,000 from drought- and salt-tolerant wild sunflowers, H. argophyllus and H. paradoxus, respectively. To create a transcript map for sunflower, we identified 605 ESTs that displayed small insertion-deletion polymorphism (SNP) variation in silico, had apparent tissue-specific expression patterns, and/or were ESTs with candidate functions in traits such as development, cell transport, metabolism, plant defense, and tolerance to abiotic stress. Primer pairs for 535 of the loci were designed from the ESTs and screened for polymorphism in recombinant inbred lines derived from a cross between the same cultivars (RHA280 x RHA801) employed for sequencing. In total, 273 of the loci amplified polymorphic products, of which 243 mapped to the 17 linkage groups previously identified for sunflower. Comparisons with previously mapped QTL revealed some cases where ESTs with putatively related functions mapped near QTLs identified in other crosses for salt tolerance and for domestication traits such as stem diameter, shattering, flowering time, and achene size.

Erratum to: Traffic injury data, policy, and public health: Lessons from Boston Chinatown

In the March 2002 issue, the following credit line was omitted from Fig. 1(a) on p. 90 (Brugge D, Lai Z, Hill, C, Rand W. Traffic Injury Data, Policy, and Public Health: Lessons from Boston Chinatown. J Urban Health. 2002;79(1):87-103): "This figure is reprinted with permission from Brugge D, A Leong, Z Lai. Can a community inject public health values into transportation questions? Public Health Rep. 1999:114:44."

Design of a compartmentalized shotgun assembler for the human genome

Two different strategies for determining the human genome are currently being pursued: one is the "clone-by-clone" approach, employed by the publicly funded project, and the other is the "whole genome shotgun assembler" approach, favored by researchers at Celera Genomics. An interim strategy employed at Celera, called compartmentalized shotgun assembly, makes use of preliminary data produced by both approaches. In this paper we describe the design, implementation and operation of the "compartmentalized shotgun assembler".

Human mdm2 mediates multiple mono-ubiquitination of p53 by a mechanism requiring enzyme isomerization

The mdm2 gene product is an important regulator of p53 function and stability. mdm2 is an E3 ubiquitin ligase for p53 and the RING finger domain of mdm2 is critical for ligase activity. Ubiquitin (Ub) conjugation is a general targeting modification and poly-ubiquitin chains specifically target proteins to the proteasome for degradation. In this report, we show that the multistep cascade of mdm2-mediated p53 ubiquitination can be reduced to three purified recombinant proteins: ubiquitin-conjugated E2, mdm2, and p53. This simplification allows enzymatic analysis of the isolated ligase reaction. The simplified reaction recapitulates the ubiquitination of p53 observed with individual components and the p53-Ub((n)) is qualitatively similar to p53-Ub((n)) detected in lactacystin-treated cells. Surprisingly, we find that p53 is modified with multiple mono-ubiquitin moieties as opposed to a poly-ubiquitin chain. Finally, kinetic analysis indicates the transfer reaction proceeds either through a modified Ping Pong mechanism involving requisite enzyme isomerization steps, or through a Rapid Equilibrium Random Bi Bi mechanism involving very large anti-cooperative interactions between the two substrate binding pockets on the enzyme, mediated through allosteric changes in enzyme structure.

[Helicobacter pylori associated gastric mucosal inflammation and histopathological assessment]

OBJECTIVE

To investigate the pathological features of Helicobacter pylori associated gastric mucosal inflammation and to establish relevant histopathological assessment standards.

METHODS

Biopsy specimens from the gastric antrum, body of stomach, and gastric angle were taken from 2 134 cases of H. pylori associated gastric mucosal inflammation. H. pylori was identified by means of rapid urase test and toluidine blue staining or immunohistological staining. The severity of mucosal inflammation was evaluated with HE staining. Ultrastucture evaluation was conducted for part of the specimens.

RESULTS

In H. pylori positive cases lymphocytic infiltration could be observed in glandulous epithelium. which was not found in normal gastric mucosa. Scoring of severity of mucosal inflammation reflected the status of H. pylori infection and was not influenced by the biopsy site, size of specimen, and direction of sectioning. Severe active inflammation could be seen in 39.6% of the H. pylori positive cases, and 0.4% of the H. pylori negative cases. The severity score of inflammation was significantly correlated with the amount of H. pylori colonization.

CONCLUSION

Reflecting the real status of H. pylori associated mucosal inflammation. The grading method reported here is simple, reliable, and easy to master.

[Effects of vascular endothelial growth factor on adhesion molecular expression of hepatocellular carcinoma HepG]

OBJECTIVE

To study the effect of vascular endothelial growth factor (VEGF) on homotypic adhesion and E-cadherin of hepatocellular carcinoma cells.

METHODS

We measured the function of homotypic adhesion with (3)H-TdR infiltration and the expression of E-cadherin with laser scanning confocal microscope.

RESULTS

After 60, 90, 120min, the values (dpm/min) of (3)H-TdR infiltration in HepG(2) cells induced by 1ng/ml, 5ng/ml VEGF were 1758.67+/-289.46, 1380.03+/-328.55, 2657.43 +/- 310.31 and 3124.30+/-262.14, 2245.60+/-273.24, 2091.52+/-213.84. The values by 10ng/ml VEGF were 1232.32+/-201.04, 2337.50+/-333.04, 2236.99 +/- 237.07, which were significantly lower than those in control group (P<0.05 or 0.01). The expression of E-cadherin in hepatocellular carcinoma cells induced by 5ng/ml VEGF was 352+/-56 and much lower than that in control group (757+/-103, P<0.01).

CONCLUSIONS

VEGF can decrease homotopic adhesion of hepatocellular carcinoma HepG(2) cell, which is connected with the less expression of E-cadherin in hepatocellular carcinoma HepG(2) cell.

[The mutation of anti-CD3 antibody (HIT3a) gene and its expression]

OBJECTIVE

To improve the expression of anti-CD(3) single chain Fv (scFv) by site mutation and identify its biological activity.

METHODS

Anti-CD(3) scFv gene was mutated by PCR, the target clones were screened by both the fingerprints of DNA restriction endonuclease digestion and Western blot, the antigen-binding activity of scFv was examined by FACS, competitive inhibition was performed with (125)I-labeled HIT3a and the cytotoxic effect mediated by the anti-CD(3) scFv-activated T lymphocytes was analyzed by (51)Cr-released assays.

RESULTS

The DNA sequencing showed that the 6th amino acid of the anti-CD(3) antibody (HIT3a) heavy chain gene was mutated from E (GAG) to Q (CAG). The expression of mutated anti-CD(3) scFv (m2) was increased by 100 times higher than that of the parent scFv, and there was no difference in the Jurkat cell (CD(3)(+))-binding activity between the (m2) and parent scFv. The preliminary results of competitive assays showed that m2 could partially block the sites of CD(3)(+) Jurkat cells where the parent antibody bound to. Cytotoxicity assays demonstrated that CD(3)AK cells induced by IL-2 and m2 showed stronger cytotoxic effect than that of LAK cells induced by IL-2 alone in vitro.

CONCLUSION

By site mutation, a high expression fragment m2 of anti-CD(3) scFv antibody was obtained. The results of some experiments indicated that m2 could bind to CD(3)(+) Jurkat cells, furthermore, by co-stimulated with IL-2, it could activate peripheral T lymphocytes and induce CD(3)AK cytotoxic effect.