Dynamic changes in RAS gene status in circulating tumour DNA: a phase II trial of first-line FOLFOXIRI plus bevacizumab for RAS-mutant metastatic colorectal cancer (JACCRO CC-11)

Background

Few prospective studies have used liquid biopsy testing in RAS-mutant metastatic colorectal cancer (mCRC), and its clinical significance remains unknown. Therefore, this study aimed to carry out a biomarker analysis by liquid biopsy using updated data of the phase II trial of FOLFOXIRI plus bevacizumab as first-line chemotherapy for RAS-mutant mCRC.

Materials and methods

A total of 64 patients who received modified FOLFOXIRI regimen (irinotecan 150 mg/m², oxaliplatin 85 mg/m², levofolinate 200 mg/m², and fluorouracil 2400 mg/m²) plus bevacizumab biweekly were enrolled. The primary endpoint was the objective response rate (ORR). Plasma samples were collected at pre-treatment, 8 weeks after treatment, and progression in participants included in the biomarker study. The levels of circulating tumour DNA (ctDNA) and specific KRAS and NRAS variants were evaluated using real-time PCR assays.

Results

There were 62 patients (median age: 62.5 years, 92% performance status 0, 27% right side) who were assessable for efficacy and 51 for biomarker analysis. ORR was 75.8% (95% confidence interval 65.1% to 86.5%). The median progression-free survival was 12.1 months, and the median overall survival (OS) was 30.2 months. In 78% of patients, RAS mutations disappeared in the ctDNA at 8 weeks after treatment; these patients tended to have better outcomes than those with RAS mutations. Interestingly, RAS mutations remained undetectable during progression in 62% of patients. Survival analysis indicated that the median OS from progression was significantly longer in patients with RAS mutation clearance than in those with RAS mutation in the ctDNA at disease progression (15.1 versus 7.3 months, hazard ratio: 0.21, P = 0.0046).

Conclusions

Our biomarker study demonstrated no RAS mutations in ctDNA at disease progression in 62% of patients with RAS-mutant mCRC. Both OS and post-progression survival were better in patients with clearance of RAS mutations in ctDNA after triplet-based chemotherapy.

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First-line FOLFOXIRI plus bevacizumab is effective for RAS-mutant mCRC with comparable efficacy in elderly patients.

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RAS mutations disappeared in ctDNA after intensive chemotherapy in 62% of patients with mCRC with RAS-mutant tumours.

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Survival time was longer in patients with RAS mutation clearance than in those with RAS mutations in ctDNA.

Does the phenotypic morphology of the human brachial plexus reflect the theoretical development of concomitant regulation in thoracolumbar spines and nerves?

BACKGROUND

Experimental evidence identified that thoracolumbar mutants caused by Hox genes 7-10 mutants also involve a craniocaudal shift and/or the addition or reduction of segments of the limb plexus roots. This study investigated whether the theoretical concomitant shift of the brachial plexus roots in human different thoracolumbar counts is shared as confirmed in those of the human lumbosacral plexus.

MATERIALS AND METHODS

The phenotypic morphology of the brachial plexus and its arterial interaction on 20 sides of 10 atypical human thoracolumbar counts out of the 354 sides of the 177 cadavers, were compared with those of 52 sides of 26 cases in a typical human vertebral formula (7C_12T_5L_5S).

RESULTS

Regardless of the course and branching patterns of the axillary artery, our results showed that the main brachial plexus roots were composed of only five segments of the 5th-9th spinal nerves, with small contributions from the 4th and/or 10th nerves. This root composition is identical to a typical human thoracolumbar formula, and therefore, neither a craniocaudal shift nor additional/reduced main roots occurred in our thoracolumbar variants.

CONCLUSIONS

Unlike the concomitant shift of the lumbosacral plexus roots, our present cases suggest that the phenotypic morphology of the human brachial plexus may be less likely to show theoretical craniocaudal shifts, further data on the root changes in different vertebral formulae are needed for its accurate validation.

OPERA tau neutrino charged current interactions

The OPERA experiment was designed to discover the vτ appearance in a vμ beam, due to neutrino oscillations. The detector, located in the underground Gran Sasso Laboratory, consisted of a nuclear photographic emulsion/lead target with a mass of about 1.25 kt, complemented by electronic detectors. It was exposed from 2008 to 2012 to the CNGS beam: an almost pure vμ beam with a baseline of 730 km, collecting a total of 1.8·1020 protons on target. The OPERA Collaboration eventually assessed the discovery of vμ→vτ oscillations with a statistical significance of 6.1 σ by observing ten vτ CC interaction candidates. These events have been published on the Open Data Portal at CERN. This paper provides a detailed description of the vτ data sample to make it usable by the whole community.

Final Results of the OPERA Experiment on ν_{τ} Appearance in the CNGS Neutrino Beam

The OPERA experiment was designed to study ν_{μ}→ν_{τ} oscillations in the appearance mode in the CERN to Gran Sasso Neutrino beam (CNGS). In this Letter, we report the final analysis of the full data sample collected between 2008 and 2012, corresponding to 17.97×10^{19} protons on target. Selection criteria looser than in previous analyses have produced ten ν_{τ} candidate events, thus reducing the statistical uncertainty in the measurement of the oscillation parameters and of ν_{τ} properties. A multivariate approach for event identification has been applied to the candidate events and the discovery of ν_{τ} appearance is confirmed with an improved significance level of 6.1σ. |Δm_{32}^{2}| has been measured, in appearance mode, with an accuracy of 20%. The measurement of the ν_{τ} charged-current cross section, for the first time with a negligible contamination from ν[over ¯]_{τ}, and the first direct evidence for the ν_{τ} lepton number are also reported.

Discovery of τ Neutrino Appearance in the CNGS Neutrino Beam with the OPERA Experiment

The OPERA experiment was designed to search for ν_{μ}→ν_{τ} oscillations in appearance mode, i.e., by detecting the τ leptons produced in charged current ν_{τ} interactions. The experiment took data from 2008 to 2012 in the CERN Neutrinos to Gran Sasso beam. The observation of the ν_{μ}→ν_{τ} appearance, achieved with four candidate events in a subsample of the data, was previously reported. In this Letter, a fifth ν_{τ} candidate event, found in an enlarged data sample, is described. Together with a further reduction of the expected background, the candidate events detected so far allow us to assess the discovery of ν_{μ}→ν_{τ} oscillations in appearance mode with a significance larger than 5σ.

Development of insulin allergy after bone marrow transplantation

BACKGROUND

Insulin allergy is a not uncommon condition even though human insulin and insulin analogues are widely used. However, the development of insulin allergy after bone marrow transplantation has not been reported.

CASE REPORT

A 44-year-old Japanese woman had aplastic anaemia and secondary haemochromatosis. She was diagnosed with having diabetes at age 32 years and had been treated with human insulin. At age 34 years, bone marrow transplantation was performed. One year later, a rash and urticaria appeared immediately after insulin injections. Intracutaneous tests were positive for both human insulins and analogues, whereas the test for protamine was negative. Furthermore, an IgE-radioallergosorbent test against insulin was positive. Thus, we diagnosed the patient with having an IgE-mediated type I allergy against insulin. Insulin therapy with insulin aspart, which showed the least skin reaction, was continued and the insulin allergy disappeared in 7 years.

CONCLUSIONS

This is the first description of insulin allergy after bone marrow transplantation. Our case underscores the effects of bone marrow cells on IgE-mediated type I allergy for insulin.

Abnormalities in the upper gastrointestinal tract in inflammatory bowel disease

The predominant histopathologic feature of inflammatory bowel disease is the infiltration of acute and chronic inflammatory cells, including polymorphonuclear neutrophils, macrophages and lymphocytes, in the affected intestine. Helicobacter pylori is recognized as the most common cause of upper gastrointestinal lesions, and Helicobacter pylori-associated gastritis is characterized by increased numbers of acute and chronic inflammatory cells. The pathogenesis of inflammatory bowel disease or Helicobacter pylori-associated gastritis involves immunological abnormalities, including the deficient or excessive expression of cytokines. The chronic inflammatory process in patients with Crohn's disease may affect any part of the gastrointestinal tract, whereas ulcerative colitis affects mainly the colon and rectum. Here, we discuss abnormalities in the upper gastrointestinal tract in inflammatory bowel disease. Although the prevalence rate of Helicobacter pylori infection is low in Crohn's disease, these patients often have abnormalities in the upper gastrointestinal tract.

Role of endoscopic ultrasonography in predicting the response to cyclosporin A in ulcerative colitis refractory to steroids

BACKGROUND AND AIMS

Although cyclosporin A has been reported to be effective in the treatment of severe ulcerative colitis, factors predicting its therapeutic efficacy remain unclear. Technical progress in endoscopic ultrasonography has improved visualisation of the structure of the colon wall. Here, to assess the value of endoscopic ultrasonography in predicting the response to cyclosporin A treatment, we evaluated the therapeutic effect of cyclosporin A by determining the pre- and post-cyclosporin A thickness of the mucosal layer in the rectum using endoscopic ultrasonography with an ultrasonic catheter probe.

PATIENTS AND METHODS

Fifteen ulcerative colitis patients who did not respond to high-doses of corticosteroids were treated with cyclosporin A by continuous intravenous infusion at 4mg/kg/day for 20 days. Before and 20 days after cyclosporin A therapy, clinical disease activity was assessed using clinical activity index scores. Colonoscopy and endoscopic ultrasonography were undertaken before and 20 days after cyclosporin A therapy.

RESULTS

Following treatment with cyclosporin A, nine patients showed a decrease in clinical activity index score by six points or more and were defined as responders, while the other six were defined as non-responders. Endoscopic ultrasonography measurement using an ultrasonic catheter probe showed that thickness of the rectal mucosal layer before cyclosporin A was significantly greater in responders than in non-responders (p<0.05). Further, thickness after cyclosporin A was statistically decreased (p<0.01) in the responders but not in the non-responders.

CONCLUSIONS

The ultrasonic catheter probe may represent a useful means of predicting and evaluating the efficacy of cyclosporin A treatment in severely ill ulcerative colitis patients.

The role of silicon in preventing appressorial penetration by the rice blast fungus

To test the hypothesis that silicon (Si) confers resistance against appressorial penetration of the rice blast fungus, the proportion of appressorial penetration into the leaf epidermis to total appressoria formed was compared among rice plants amended with various rates of silica gel to those plants nonamended. The amounts of Si in the youngest leaves were consistent with the amounts of silica gel applied to the rice plants. Relative Si levels on the adaxial surface of leaves as detected by energy dispersive X-ray analysis also increased with the amounts of silica gel applied. Based on light microscopic observation of the adaxial surface of rice leaves, the proportion of appressorial penetration was reduced by increasing amounts of silica gel applied and increased with the length of period after spray inoculation. Consequently, these results strongly support the hypothesis and suggest that Si in the leaf epidermis may confer resistance against appressorial penetration. Meanwhile, the number of lesions per leaf also decreased with the amount of Si applied, while only a certain part of penetrated appressoria could become sporulating susceptible lesions. This suggests that Si also confers physiological resistance against blast infection after the penetration.

Isolation and characterisation of four cDNAs encoding neuromedin U (NMU) from the brain and gut of goldfish, and the inhibitory effect of a deduced NMU on food intake and locomotor activity

In rodents, neuromedin U (NMU; U for its original effects examined in the uterus) is a multifunctional neuropeptide implicated in the regulation of the circulatory and digestive systems and energy homeostasis, especially appetite. However, there is no available information on the nature and physiological roles of NMU in fish. Therefore, we attempted to isolate and characterise transcripts encoding NMU from the brain and gut of the goldfish, and to examine the involvement of NMU in the regulation of feeding behaviour in this species. We identified four cDNAs encoding three NMU orthologs from the brain and gut. Putative peptides consisting of 21, 25 and 38 amino acid residues (NMU-21, NMU-25 and NMU-38) were deduced from their nucleotide sequences. Two mRNAs for NMU-25 were strongly expressed in the gut and weakly expressed in the brain and testis. By contrast, mRNA for NMU-21 was strongly expressed in the brain and weakly expressed in the peripheral tissues. Expression of mRNA for NMU-38 was weakly expressed only in the brain. Therefore, we examined the effect of feeding status on the expression of NMU-21 mRNA in the brain. Fasting for 7 days induced a significant decrease in the expression levels of NMU-21 mRNA in the brain. We also synthesised NMU-21 after deducing its C-terminal amide from the NMU-21 mRNA, and then investigated the effect of intracerebroventricular (i.c.v.) administration of NMU-21 on food intake and locomotor activity in the goldfish. NMU-21, injected i.c.v., suppressed food intake and locomotor activity in a dose-dependent manner. These results suggest that NMU orthologs exist in fish, and that the NMU-21 deduced from them can potently inhibit food intake and locomotor activity in goldfish.

Usefulness of an elemental diet in Crohn's disease

Crohn's disease is a chronic relapsing disease for which no complete cure is available. Although drug therapy with agents such as corticosteroids and azathiopurine is useful, the long-term side effects of these drugs are problematic. The advent of infliximab has recently brought a change in treatment, but the long-term side effects of this agent remain uncertain. In contrast, nutritional therapy produces no drug-induced side effects and is effective in inducing and maintaining remission. However, sufficient efficacy cannot be expected in patients in whom compliance with nutritional regimens gradually decreases owing to unpalatability. In these cases, combination therapy with agents such as immunosuppressors and infliximab may be useful.

DNA hypermethylation in colorectal neoplasms and inflammatory bowel disease: a mini review

DNA hypermethylation is one of major epigenetic changes. Hypermethylation of many genes has been reported to be related with carcinogenesis and tumor progression of colorectal cancer. Some genes including estrogen receptor is associated with ageing, and changes related with ageing may be accelerated in inflammatory bowel disease. Furthermore, fecal DNA methylation will be able to be used as a marker of colorectal cancer and inflammatory bowel disease. Evaluation of hypermethylation potentially contributes diagnosis of colorectal diseases.

The interaction of host genetic factors and Helicobacter pylori infection

Helicobacter pylori plays an important role in the development of atrophic gastritis that represents the most recognized pathway in multistep gastric carcinogenesis. Recent studies suggest that a combination of host genetic factors, bacterial virulence factors, and environmental and lifestyle factors determine the severity of gastric damage and the eventual clinical outcome of Helicobacter pylori infection. As to bacterial virulence factors, a high proportion of Japanese strains are cagA(+)vacAs1. The CagA protein is injected from attached Helicobacter pylori into gastric epithelial cells and the CagA-SHP-2 interactions elicit cellular changes that increase the risk of carcinogenesis. Host cytokine gene polymorphisms and a frequent single nucleotide polymorphism in the PTPN11 gene that encodes SHP-2 may associate with gastric atrophy among Helicobacter pylori-infected subjects. Prevention of gastric cancer requires the development of better screening strategies for determining eradication candidates and further improvement of treatments of Helicobacter pylori infection.

Pit patterns in rectal mucosa assessed by magnifying colonoscope are predictive of relapse in patients with quiescent ulcerative colitis

BACKGROUND

Relapse of ulcerative colitis is difficult to predict by routine colonoscopy. A high-resolution video-magnifying colonoscope with chromoscopy enables the observation of colorectal mucosal pit patterns.

AIMS

To investigate the association of pit patterns as assessed by magnifying colonoscopy (MCS) with histological inflammation and mucosal chemokine activity in patients with quiescent ulcerative colitis, and to prospectively analyse the prognostic factors that may predict exacerbations.

METHODS

MCS was performed in 113 patients with ulcerative colitis in remission. Pit patterns in the rectal mucosa were classified into four MCS grades on the basis of size, shape and arrangement. Mucosal interleukin (IL) 8 activity was measured in biopsy specimens of rectal mucosa and the specimens were assessed for histological disease activity. The patients were then followed until relapse or for a maximum of 12 months. Multivariate survival analysis was carried out to determine the independent predictors of clinical relapse.

RESULTS

A positive correlation was identified between MCS grade, histological grade (p = 0.001) and mucosal IL8 activity (p<0.001). Multivariate proportional hazard model analysis showed that MCS grade was a significant predictor of relapse (relative risk 2.06, p = 0.001). Kaplan-Meier estimate of relapse during 12 months of follow-up was found to increase with increasing MCS grade, with values of 0% for grade 1, 21% for grade 2, 43% for grade 3 and 60% for grade 4.

CONCLUSION

MCS grading is associated with the degree of histological inflammation and mucosal IL8 activity in patients with quiescent ulcerative colitis, and may predict the probability of subsequent disease relapse in patients with ulcerative colitis in remission.

Epithelial and stromal genetic instability contributes to genesis of colorectal adenomas

BACKGROUND

Previously, we indicated that stromal genetic instability might contribute to tumorigenesis of both sporadic and ulcerative colitis associated colorectal adenocarcinomas. Considering the established adenoma-adenocarcinoma sequence, in this study we analysed genetic instability in colorectal adenoma cells and surrounding stroma.

METHODS

In 164 colorectal tumours (34 hyperplastic polyps, 38 tubular adenomas with low grade dysplasia (TA-L), 51 tubular adenomas with high grade dysplasia (TA-H), and 41 invasive carcinomas), epithelial and stromal genetic instability with National Cancer Institute standard microsatellite markers and chromosome 17 (Chr17) markers, were analysed by a combination of laser capture microdissection and GeneScan approaches.

RESULTS

While frequencies of both loss of heterozygosity (LOH) and microsatellite instability (MSI) were extremely low in hyperplastic polyps, LOH in tubular adenomas was detected in both epithelial (TA-L 13.2%, TA-H 27.5%) and stromal (5.3% and 5.9%, respectively) elements, along with MSI (5.3% and 13.7%, and 5.3 and 5.9%, respectively). Frequencies of epithelial alterations were higher in TA-H than in TA-L, and greatest in the carcinoma group. On the other hand, frequencies of stromal LOH or MSI were almost constant (5.3% approximately 17.1%, 5.3% approximately 17.1%, respectively) in adenomas and invasive carcinomas. In addition, p53 was found to be significantly overexpressed in a greater proportion of TA-L with LOH than in those without genetic instability.

CONCLUSION

The results indicate the presence of genetic alterations in stroma from an early stage of carcinogenesis, accompanied by stepwise increasing genetic instability of epithelia with progression to cancer. Thus microenvironmental changes due to genetic alteration in Chr17 markers in stromal cells may play an important role in colon adenoma and adenocarcinoma development.

Effects of Elevated Atmospheric CO(2) Concentration on the Infection of Rice Blast and Sheath Blight

ABSTRACT The effect of elevated atmospheric CO(2) concentration on rice blast and sheath blight disease severity was studied in the field in northern Japan for 3 years. With free-air CO(2) enrichment (FACE), rice plants were grown in ambient and elevated ( approximately 200 to 280 mumol mol(-1) above ambient) CO(2) concentrations, and were artificially inoculated with consist of Magnaporthe oryzae. Rice plants grown in an elevated CO(2) concentration were more susceptible to leaf blast than those in ambient CO(2) as indicated by the increased number of leaf blast lesions. Plants grown under elevated CO(2) concentration had lower leaf silicon content, which may have contributed to the increased susceptibility to leaf blast under elevated CO(2) concentrations. In contrast to leaf blast, panicle blast severity was unchanged by the CO(2) enrichment under artificial inoculation, whereas it was slightly but significantly higher under elevated CO(2) concentrations in a spontaneous rice blast epidemic. For naturally occurring epidemics of the sheath blight development in rice plants, the percentage of diseased plants was higher under elevated as opposed to ambient CO(2) concentrations. However, the average height of lesions above the soil surface was similar between the treatments. One hypothesis is that the higher number of tillers observed under elevated CO(2) concentrations may have increased the chance for fungal sclerotia to adhere to the leaf sheath at the water surface. Consequently, the potential risks for infection of leaf blast and epidemics of sheath blight would increase in rice grown under elevated CO(2) concentration.

Interleukin 1B proinflammatory genotypes protect against gastro-oesophageal reflux disease through induction of corpus atrophy

BACKGROUND AND AIMS

The relationship between Helicobacter pylori infection and gastro-oesophageal reflux disease (GORD) is controversial but it is accepted that GORD is associated with increased exposure to gastric acidity. The proinflammatory interleukin (IL)-1B polymorphisms increase the risk of hypochlorhydria and gastric atrophy. We examined the association between proinflammatory cytokine gene polymorphisms, presence of gastric atrophy, and risk of GORD in H pylori positive and negative subjects in Japan.

METHODS

We studied 320 consecutive dyspeptic patients without peptic ulcers or cancers. GORD symptoms were scored using the Carlsson-Dent questionnaire and erosive oesophagitis was assessed endoscopically. H pylori infection was diagnosed by urea breath test, histological examination, and serology. Gastric atrophy was assessed histologically, and polymorphisms in the IL-1B, IL-10, and tumour necrosis factor alpha (TNF-A) genes were genotyped.

RESULTS

Two hundred and eight patients were H pylori positive and 112 were negative. One hundred and eight (34%) were found to have erosive oesophagitis by endoscopic criteria (grade A: 78; grade B: 23; grade C: 6; grade D: 1). Erosive oesophagitis and GORD symptoms were significantly more common in H pylori negative compared with H pylori positive subjects (p<0.05). H pylori positive subjects were more likely to have corpus gastric atrophy than H pylori negative subjects (p<0.001). Among H pylori positive patients, those without erosive oesophagitis or GORD symptoms were significantly more likely to have corpus atrophy than subjects with erosive oesophagitis or GORD symptoms (p<0.05). Among H pylori positive patients, subjects homozygous for the proinflammatory allele IL-1B-511T had a significantly lower risk of erosive oesophagitis (odds ratio (OR) 0.06 (95% confidence interval (CI) 0.006-0.51); p=0.01) and GORD symptoms (OR 0.10 (95% CI 0.01-0.85); p=0.04) compared with those homozygous for the -511C allele, while none of the two other proinflammatory cytokine gene polymorphisms had significant correlations with erosive oesophagitis or GORD symptoms.

CONCLUSIONS

A proinflammatory IL-1B genotype is associated with increased risk of atrophy and decreased risk of GORD in H pylori infected subjects in Japan. These data indicate that in some genetically predisposed subjects, H pylori infection may protect against GORD through induction of gastric atrophy.

Reduction of mucin-1 gene expression associated with increased Escherichia coli adherence in the canine uterus in the early stage of dioestrus

The relation between adherence of Escherichia coli and expression of mucin-1 (Muc1: an integral membrane mucin) mRNA in the endometrium was studied in beagle bitches at different stages of the oestrous cycle and in those with cystic endometrial hyperplasia/pyometra complex (pyometra). The number of E. coli adhering to the endometrium was low at pro-oestrus and oestrus and increased at the early stage (day 10) of dioestrus, corresponding to the implantation period; it declined thereafter. Adhesion of the organisms to endometrial epithelial cells collected at day 10 of dioestrus was inhibited by the addition of D-mannose. When endometrial epithelial cells collected at pro-oestrus were treated with hyaluronidase, an enzyme that digests mucins, the numbers of E. coli adhering to the cells tended to increase. With polymerase chain reaction analysis it was possible to detect Muc1 gene transcripts in the endometrium at all stages of the oestrous cycle, although the level of Muc1 mRNA decreased by day 10 of dioestrus. The levels of Muc1 mRNA in bitches with a clinical stage of pyometra were low and comparable to those at day 10 of dioestrus. The number of E. coli adhering to the endometrium and Muc1 mRNA levels in the endometrium were inversely correlated (r=-0.77, P<0.01). Immunohistochemical analysis showed little staining for Muc1 in the endometrial epithelia at day 10 of dioestrus and in bitches with pyometra. These results suggest that reduction of Muc1 expression is associated with increased E. coli adherence in the canine uterus at the early stage of dioestrus, possibly facilitating the development of pyometra.

GP2/THP gene family of self-binding, GPI-anchored proteins forms a cluster at chromosome 7F1 region in mouse genome

We investigated the genomic organization of pancreatic zymogen granule membrane-associated protein GP2, a GPI-anchored protein exhibiting self-aggregation at acidic pH, in order to construct a gene-knockout mouse. Cloning and analysis of lambda clones encoding GP2 from 129 Svj mouse genomic DNA libraries showed that the GP2 gene spans about 16.8 kb and includes 11 exons. Identifiable functional domains including a signal sequence, an EGF-like motif, a putative condensing ZP domain, a GPI-anchor attachment site, and a transmembrane sequence for GPI anchoring are encoded in separate exons. Using FISH, the GP2 gene was mapped to mouse chromosome 7F1 near the gene for THP, a GP2 homolog expressed in the cells of thick ascending loop of Henle (TALH) in the kidney. Further analysis of the mouse genome revealed that the THP and GP2 genes are adjacent to one another and are separated by only 3.5 kb in the 7F1 locus. Additionally, the overall structure of the THP gene, 16.2kb with 11 exons, was strikingly similar to that of GP2. This finding suggests that the GP2 and THP genes were generated by gene duplication and evolved separately to acquire regulatory elements leading to tissue-specific expression. Comparative analysis revealed that the 5' flanking region of the THP gene is similar to the first intron of NKCC2, a TALH cell-specific ion-transporter gene. The promoter region of the GP2 gene shares cis-elements found in other pancreas-specific genes. Using this genetic information, a GP2 null mutation was successfully introduced into an ES cell line, and an animal model was established without disruption of THP expression.

Regeneration of transformed verbena (Verbena x hybrida) by Agrobacterium tumefaciens

Verbena (Verbena x hybrida), an important floricultural species, was successfully regenerated from stem segments on Murashige and Skoog's basal medium supplemented with thidiazuron and indole-3-acetic acid. A transformation system was developed using cvs. Temari Scarlet, Temari Sakura, Tapien Rose and TP-P2. Agrobacterium tumefaciens strain Agl0 harboring the sGFP gene was infected into stem segments. Transformation efficiency was improved by evaluating and manipulating the age of the plant material, the concentration of kanamycin in the medium during selection, and the length of the culture period in the dark. After 2-3 months of culture on the selection medium, GFP-positive shoots were obtained in all four of the cultivars tested. These shoots were successfully acclimated and set flowers within 2-3 months in a greenhouse. GFP was expressed in all of the organs including the floral parts. Stable genomic transformation was confirmed by Southern blot analysis. No morphological differences were observed between the transformed plants and their host plants.

Disruption of the midkine gene (Mdk) resulted in altered expression of a calcium binding protein in the hippocampus of infant mice and their abnormal behaviour

BACKGROUND

Midkine (MK) is a growth factor implicated in the development and repair of various tissues, especially neural tissues. However, its in vivo function has not been clarified.

RESULTS

Knockout mice lacking the MK gene (Mdk) showed no gross abnormalities. We closely analysed postnatal brain development in Mdk(-/-) mice using calcium binding proteins as markers to distinguish neuronal subpopulations. Intense and prolonged calretinin expression was found in the dentate gyrus granule cell layer of the hippocampus of infant Mdk(-/-) mice. In infant Mdk(+/+) mice, calretinin expression in the granule cell layer was weaker, and had disappeared by 4 weeks after birth, when calretinin expression still persisted in Mdk(-/-) mice. Furthermore, 4 weeks after birth, Mdk(-/-) mice showed a deficit in their working memory, as revealed by a Y-maze test, and had an increased anxiety, as demonstrated by the elevated plus-maze test.

CONCLUSION

Midkine plays an important role in the regulation of postnatal development of the hippocampus.

Syndecan-4 deficiency leads to high mortality of lipopolysaccharide-injected mice

Syndecan-4 is a transmembrane heparan sulfate proteoglycan belonging to the syndecan family. Following intraperitoneal injection of lipopolysaccharide (LPS), syndecan-4-deficient mice exhibited high mortality compared with wild-type controls. Severe endotoxin shock was observed in the deficient mice: systolic blood pressure and left ventricular fractional shortening were lower in the deficient mice than in the wild-type controls 9 h after LPS injection. Although histological examinations revealed no apparent differences between two groups, the plasma level of interleukin (IL)-1beta was higher in the deficient mice than in the wild-type controls 9 h after LPS injection. Consistent with the regulatory roles of syndecan-4, its expression in monocytes and endothelial cells of microvasculature increased in the wild-type mice after LPS administration. Although IL-1beta was produced to the same extent by macrophages from syndecan-4-deficient and wild-type mice after LPS stimulation, inhibition of its production by transforming growth factor-beta1 was impaired in the syndecan-4-deficient macrophages. These results indicate that syndecan-4 could be involved in prevention of endotoxin shock, at least partly through the inhibitory action of transforming growth factor-beta1 on IL-1beta production.

Diverse chalcone synthase superfamily enzymes from the most primitive vascular plant, Psilotum nudum

Psilotum nudum Griseb is a pteridophyte and belongs to the single family (Psilotaceae) of the division, Psilophyta. Being the only living species of a once populated division, P. nudum is the most primitive vascular plant. Chalcone synthase (CHS; EC 2.3.1.74) superfamily enzymes are responsible for biosyntheses of diverse secondary metabolites, including flavonoids and stilbenes. Using a reverse transcription-polymerase chain reaction strategy, four CHS-superfamily enzymes (PnJ, PnI, PnL and PnP) were cloned from P. nudum, and heterologously expressed in Escherichia coli. These four enzymes of 396-406 amino acids showed sequence identity of > 50% among themselves and to other higher-plant CHS-superfamily enzymes. PnJ and PnP preferred p-coumaroyl-CoA and isovaleryl-CoA respectively, as starter CoA and catalyzed CHS-type ring formation, indicating that they are CHS and phlorisovalerophenone synthase, respectively. On the other hand, PnI and PnL preferred cinnamoyl-CoA as starter CoA and catalyzed stilbene synthase-type cyclization and thus were determined to be pinosylvin synthases (EC 2.3.1.146). In addition, PnE, which uniquely contains a glutamine in place of otherwise strictly conserved histidine, had no apparent in vitro catalytic activity. Phylogenetic analysis indicated that these P. nudum clones form a separate cluster together with Equisetum arvense CHS. This cluster of pteridophytes is located next to the cluster formed by pine (gymnosperm) enzymes, in agreement with their evolutionary relationships. Psilotum nudum represents a plant with the most diverse CHS-superfamily enzymes and this ability to diverge may have provided a survival edge during evolution.