Epidermal growth factor-induced tumor cell invasion and metastasis initiated by dephosphorylation and downregulation of focal adhesion kinase

Upregulated epidermal growth factor (EGF) receptor (EGFR) expression and EGFR-induced signaling have been correlated with progression to invasion and metastasis in a wide variety of carcinomas, but the mechanism behind this is not well understood. We show here that, in various human carcinoma cells that overexpress EGFR, EGF treatment induced rapid tyrosine dephosphorylation of focal adhesion kinase (FAK) associated with downregulation of its kinase activity. The downregulation of FAK activity was both required and sufficient for EGF-induced refractile morphological changes, detachment of cells from the extracellular matrix, and increased tumor cell motility, invasion, and metastasis. Tumor cells with downregulated FAK activity became less adherent to the extracellular matrix. However, once cells started reattaching, FAK activity was restored by activated integrin signaling. Moreover, this process of readhesion and spreading could not be abrogated by further EGF stimulation. Interruption of transforming growth factor alpha-EGFR autocrine regulation with an EGFR tyrosine kinase inhibitor led to a substantial increase in FAK tyrosine phosphorylation and inhibition of tumor cell invasion in vitro. Consistent with this, FAK tyrosine phosphorylation was reduced in cells from tumors growing in transplanted, athymic, nude mice, which have an intact autocrine regulation of the EGFR. We suggest that the dynamic regulation of FAK activity, initiated by EGF-induced downregulation of FAK leading to cell detachment and increased motility and invasion, followed by integrin-dependent reactivation during readhesion, plays a role in EGF-associated tumor invasion and metastasis.

[Peri-operative management in patients with thoracic aortic aneurysm complicated with cardiac tamponade]

We retrospectively summarized the peri-operative hemodynamic status and respiratory function in patients with thoracic aneurysms complicated with cardiac tamponade (Tamponade Group; n = 6) in comparison with patients complicated with hemorrhagic pericardial effusion without symptom of cardiac tamponade (Effusion Group; n = 10). There were no difference with regard to preoperative heart rate, pericardial effusion quantity, frequency of emergent operation and operation time. Preoperative hemodynamic status was worse in Tamponade Group than in Effusion Group. The cardiac indices of 12 h, 24 h, 48 h after operation in Tamponade Group were 2.60 +/- 0.60, 2.29 +/- 0.42, 1.95 +/- 0.33 l/min/m2 respectively, those were not different in Effusion Group. The differences between O2 tension in alveolar and arterial blood O2 tension (A-aDO2) and oxygenation indices (OI) of 12 h and 24 h after operation were significantly worse in Tamponade Group than in Effusion Group, but those of 48 h were not different. The operative mortality was 50% in Tamponade Group, and none in Effusion Group. It is very important to maintain hemodynamic status before operation, to perform complete repair (graft replacement) as early as possible and to care intensively after operation for thoracic aortic aneurysm complicated with cardiac tamponade.

A functional myo-inositol dehydrogenase gene is required for efficient nitrogen fixation and competitiveness of Sinorhizobium fredii USDA191 to nodulate soybean (Glycine max [L.] Merr.)

Inositol derivative compounds provide a nutrient source for soil bacteria that possess the ability to degrade such compounds. Rhizobium strains that are capable of utilizing certain inositol derivatives are better colonizers of their host plants. We have cloned and determined the nucleotide sequence of the myo-inositol dehydrogenase gene (idhA) of Sinorhizobium fredii USDA191, the first enzyme responsible for inositol catabolism. The deduced IdhA protein has a molecular mass of 34,648 Da and shows significant sequence similarity with protein sequences of Sinorhizobium meliloti IdhA and MocA; Bacillus subtilis IolG, YrbE, and YucG; and Streptomyces griseus StrI. S. fredii USDA191 idhA mutants revealed no detectable myo-inositol dehydrogenase activity and failed to grow on myo-inositol as a sole carbon source. Northern blot analysis and idhA-lacZ fusion expression studies indicate that idhA is inducible by myo-inositol. S. fredii USDA191 idhA mutant was drastically affected in its ability to reduce nitrogen and revealed deteriorating bacteroids inside the nodules. The number of bacteria recovered from such nodules was about threefold lower than the number of bacteria isolated from nodules initiated by S. fredii USDA191. In addition, the idhA mutant was also severely affected in its ability to compete with the wild-type strain in nodulating soybean. Under competitive conditions, nodules induced on soybean roots were predominantly occupied by the parent strain, even when the idhA mutant was applied at a 10-fold numerical advantage. Thus, we conclude that a functional idhA gene is required for efficient nitrogen fixation and for competitive nodulation of soybeans by S. fredii USDA191.

Prokaryotically expressed Buthus martensii Karsch insect depressant toxin has insecticidal effects

An insect depressant toxin Buthus martensii Karsch insect toxin 4 (BmK IT(4)) cDNA was cloned into the prokaryotic expression vector pSW202 and expressed in HB101 host cells. The authenticity of this in vitro expressed peptide was confirmed by Western blotting, mass spectrometry and N-terminal peptide sequencing. Bioassays using growth media supplemented with BmK IT(4) demonstrated that, at the end of the 5-day experimental period, about 77% of the testing cotton bollworm larvae were killed. Furthermore, the average weight picked up by larvae grown on BmK IT(4) containing media amounts only to 0.7% of that of control group. Our results indicate that BmK IT(4) may be used for biological control of insect damages in place of other traditional insecticides.

Flashlamp-pumped pulsed dye laser in treatment of port-wine stains

OBJECTIVE

To assess the effectiveness of the flashlamp-pumped pulsed dye laser (Photogeneca V, Synosure Corp, Boston, United States) in the treatment of port-wine stains.

METHODS

One hundred and ninety-four consecutive patients with port-wine stains were treated with a flashlamp-pumped pulsed dye laser in Peking Union Medical College Hospital from January 1998 to August 1999.

RESULTS

Of 194 patients who completed treatment, 56.2% had more than 60% fading of the lesion and only 6.7% had less than 20% fading. An average of 3.6 treatments were needed to achieve more than 60% fading. The response was better in children than in adults, although the difference was not significant. Pigmentary change (usually transient) occurred in 3.1% of patients.

CONCLUSIONS

This study confirms the efficacy of the flashlamp-pumped pulsed dye laser in the treatment of port-wine stains in children and adults.

[The analysis of rice total RNA by capillary electrophoresis]

When the RNase was eliminated through backing at 200 degrees C or treated by diethylpyrocarbonate (DEPC), the total RNA of rice could be separated within 15 min using 1.0%T, 0%C linear polyacrylamide as sieving matrix and 7 mol/L urea as denaturant. The tRNA of rice can be separated into two classes and about nine peaks when high concentrated polyacrylamide sieving matrix (5.0%T, 0%C) was used. This technique could provide one of the rapid and accurate methods for the determination of RNA in plants.

Retrospective study of mechanical ventilation in treating multiple trauma accompanied with craniocerebral injury

OBJECTIVE

To explore the importance of mechanic al ventilation (MV) in treating multiple trauma mainly accompanied with cerebral injury and improve the treatment level.

METHODS

All 116 patients who suffered from multiple trauma accompanied with mainly cerebral injury were analyzed. Rank correlation and Chi-square test were made between MV with GCS, ISS, and whether shock or not.

RESULTS

The MV was correlated with GCS, ISS scores, and whether shock or not markedly. Furthermore, when GCS <or=8, the ratio of MV was about 70%. When ISS >or=35, the ratio of MV was about 85%.

CONCLUSIONS

During the treatment of multiple trauma accompanied with cerebral injury, the principle of "early MV, early withdraw" and "individualism" should be insisted on. For patients accompanied with shock, the optimum PEEP is very important. Proper and active MV is of great importance and can improve the treatment level markedly.

GnRH antagonists: a new generation of long acting analogues incorporating p-ureido-phenylalanines at positions 5 and 6

A series of antagonists of gonadotropin-releasing hormone (GnRH) of the general formula Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph/4Amf(P)-D4Aph/D4Amf(Q)-Leu-ILys-Pro-DAla-NH2 was synthesized, characterized, and screened for duration of inhibition of luteinizing hormone release in a castrated male rat assay. Selected analogues were tested in a reporter gene assay (IC50 and pA2) and an in vitro histamine release assay. P and Q contain urea/carbamoyl functionalities designed to increase potential intra- and intermolecular hydrogen bonding opportunities for structural stabilization and peptide/receptor interactions, respectively. These substitutions resulted in analogues with increased hydrophilicity and a lesser propensity to form gels in aqueous solution than azaline B [Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(Atz)-D4Aph(Atz)-Leu-ILys-Pro-DAla-NH2 with Atz = 3'-amino-1H-1',2',4'-triazol-5'-yl, 5], and in some cases they resulted in a significant increase in duration of action after subcutaneous (s.c.) administration. Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(L-hydroorotyl)-D4Aph(carbamoyl)-Leu-ILys-Pro-DAla-NH2 (acetate salt is FE200486) (31) and eight other congeners (20, 35, 37, 39, 41, 45-47) were identified that exhibited significantly longer duration of action than acyline [Ac-D2Nal-D4Cpa-D3Pal-Ser-4Aph(Ac)-D4Aph(Ac)-Leu-ILys-Pro-DAla-NH2] (6) when administered subcutaneously in castrated male rats at a dose of 50 microg in 100 microL of phosphate buffer. No correlation was found between retention times on a C18 reverse phase column using a triethylammonium phosphate buffer at pH 7.0 (a measure of hydrophilicity) or affinity in an in vitro human GnRH report gene assay (pA2) and duration of action. FE200486 was selected for preclinical studies, and some of its properties were compared to those of other clinical candidates. In the intact rat, ganirelix, abarelix, azaline B, and FE200486 inhibited plasma testosterone for 1, 1, 14, and 57 days, respectively, at 2 mg/kg s.c. in 5% mannitol (injection volume = 20 microL). Based on the information that 31, 33, 35 and 37 were significantly shorter acting than acyline or azaline B after intravenous administration (100 microg/rat), we surmised that the very long duration of action of the related FE200486 (for example) was likely due to unique physicochemical properties such as solubility in aqueous milieu, comparatively low propensity to form gels, and ability to diffuse at high concentrations in a manner similar to that described for slow release formulations of peptides. Indeed, in rats injected s.c. with FE200486 (2 mg/kg), plasmatic concentrations of FE200486 remained above 5 ng/mL until day 41, and the time after which they dropped below 3 ng/mL and plasma LH levels started rising until full recovery was reached at day 84 with levels of FE200486 hovering around 1 ng/mL. Additionally, FE200486 was less potent at releasing histamine from isolated rat mast cells than any of the GnRH antagonists presently described in preclinical reports.

Vertebral wedge angle measured by morphometric X-ray absorptiometry

Vertebral wedge angle is greater in older men than in women of similar age, and increases with age in men. Wedge angle may depend less on bone size than other methods (for example, height ratios), and thus could be more effective at identifying wedge deformities. We aimed to compare mean wedge angle measured by morphometric X-ray absorptiometry (MXA) in young men and women, to assess the effect of age on wedge angle in women, and to compare wedge angle and anterior-posterior (ha/hp) height ratios for the identification of vertebral deformities. Mean wedge angle was similar in normal men (n = 46) and women (n = 106) ages 22-50 years, and did not change significantly with age in normal women ages 22-83 years (n = 222). MXA reference intervals for ha/hp ratios (trimmed mean minus 3.0 SD) and wedge angle (trimmed mean +/- 3.0, 2.5 and 2.0 SD) were used to identify vertebral wedge deformities in 83 women with osteoporosis, ages 49-87 years. For agreement with semiquantitative assessment of radiographs (SQ), kappa (kappa) = 0.76 for wedge angle mean plus 2.0 SD, and 0.74 for ha/hp height ratio mean minus 3.0 SD. Sensitivity was marginally better for wedge angle plus 2.0 SD than for ha/hp when all SQ grades of deformity were included, but there was no difference between methods for detection of moderate to severe deformities (grades 2 to 3). Diagnostic values for the two approaches were broadly similar. The results of this analysis do not provide strong evidence for the preferential use of the wedge angle approach.

Longitudinal evaluation of morphometric X-ray absorptiometry for the identification of vertebral deformities

Morphometric X-ray absorptiometry (MXA) has not been evaluated for the identification of incident vertebral deformities. The reliability of longitudinal measurements in quantitative vertebral morphometry is influenced by the precision of the technique. Long-term precision in vitro (weekly MXA phantom scans) assessed by retrospective cumulative sum (Cusum) analysis, detected one event during a 6-month period when the measurement process was 'out of control'. Inspection of service records revealed that repair work was performed around this timepoint. The coefficient of variation (CV) for long-term precision (vertebral heights) in a population-based sample of postmenopausal women ages 56 to 83, mean 65+/-6 years (n = 48), was 4.0% for morphometric radiography (MRX), 2.9% for MXA using the compare facility for analysis of serial scans, and 3.2% when 'compare' was not used. In women with osteoporosis ages 49 to 87, mean 67+/-9 years (n = 50). the CV was 5.0% for MRX, 4.1% for MXA using 'compare' and 8.5% without 'compare'. Precision errors for height ratios (MRX and MXA) were greater than for vertebral heights. Incident deformities were identified by MRX and MXA in the women with osteoporosis, using point prevalence, 20% minimum reduction in vertebral height, and percent least significant change (LSC) in vertebral heights and height ratios. Semiquantitative analysis of radiographs by a radiologist (Genant method) was used as the gold standard. The results were similar for MRX and MXA, and all morphometric criteria identified a similar proportion of true incident deformities, although the false positive rate was generally greater for the height ratio approaches. MXA has good long-term precision and is comparable to MRX for the identification of incident deformities when scans are analyzed with the compare facility.

Short-term precision for morphometric X-ray absorptiometry

Morphometric X-ray absorptiometry (MXA) is a low-radiation technique used for the identification of vertebral deformities. The reliability of MXA measurements is dependent on the precision of the technique, and this is influenced by system error, variability associated with morphometric analysis, and variability within study populations. Short-term precision in vivo affects the identification of prevalent deformities, and may vary according to the age and health status of the study population. The aims of this study were to measure short-term precision in vitro and in vivo for MXA, and to compare intraoperator variability for repeat marking of radiographs in morphometric radiography (MRX) and scan images in MXA. For short-term precision in vitro (based on 30 consecutive MXA phantom scans), the coefficient of variation (CV) was approximately 1%. Intraoperator variability for repeat marking of baseline radiographs and MXA scans (marked without the compare facility) in a population-based group of 32 postmenopausal women, was significantly lower for MRX (CV for vertebral heights = 1.5%) than for MXA (CV = 2.9%). The CV for duplicate same-day MXA scans performed in subjects with osteoporosis (n = 20) was 2.2% for vertebral heights between T8 and L4 using the compare facility, and 4.8% when scans were analyzed without the compare facility. We conclude that short-term precision for MXA is good for vertebrae T8 to L4, but the technique is limited due to poor image resolution in the upper thoracic vertebrae. Intraoperator variability for repeat marking was lower for MRX, but the error associated with marking MXA scans remained below the minimum change required for identification of a vertebral deformity.

[Current status of organotin studied in China and abroad]

The toxicity of organotin compounds and the current pollution status in China and abroad is discussed. Regulations and limitations on the usage of organotin compounds in western countries are introduced briefly in this paper. The examination results showed that the most Chinese harbors, rivers as well as larger lakes were contaminated by organotin, especially by tribuyltin compounds. Regulations for limiting the use of butyltin compounds as antifouling paints in Chinese marine industries are imperatively needed. Actions toward for the investigation of organotin contamination levels in food chains and in household commodities are also highly desired.

[Study on the abnormal gene expression of inducible nitric oxide synthase (iNOS) in rabbit myocardium after high voltage electrical injury]

OBJECTIVE

To elucidate the effects of high voltage electrical injury on the mRNA expression of iNOS And endothelin-1 (ET-1) in rabbit myocardium.

METHODS

Rabbits inflicted by high voltage electrical injury were employed as the model. Reverse transcription PCR (RT-PCR) and serum enzyme measurement were used in the detection of the expression levels of iNOS mRNA and ET-1 mRNA of rabbit myocardial tissue and plasma creatine kinase (CK) content.

RESULTS

The expression of iNOS mRNA in rabbit myocardial tissue after high voltage electrical injury increased at 6 to 8 postburn hours (PBH) and decreased thereafter. The plasma contents of CK and ET-1 mRNA reached their peak values at 2 PBH.

CONCLUSION

The increase of iNOS mRNA might protect myocardial tissue from electrical injury.

mRNA isolation in a microfluidic device for eventual integration of cDNA library construction

mRNA isolation for the purpose of cDNA library construction was performed in a microfluidic chip device using paramagnetic oligo-dT beads. The simple Y-intersection flow design mixes beads and sample on-chip, and uses magnetic trapping to capture, then release the beads. The capillary gel electrophoresis (CGE) detection of the total unamplified mRNA isolated on-chip, and of a reverse transcription-polymerase chain reaction (RT-PCR) amplified rare gene indicated that mRNA could be captured by oligo-dT beads on-chip, had very good integrity and was suitable for constructing a cDNA library. The limit of detection for the rare bicoid gene of Drosophila Melanogaster corresponded to the capture of approximately 2.8 ng of total mRNA from 0.85 microgram of total RNA (TRNA) within the microchip. As much as 34 ng of total mRNA was estimated to be captured from 10 micrograms of TRNA.

[High temperature Raman spectroscopic study of the structure of sodium disilicate crystal, glass and its melt]

The structure of Na2Si2O5 from room temperature up to 1,773 K are studied by high temperature Raman spectroscopy using copper vapor pulse laser and integral time-resolved detection technique without any black-body radiation effect on spectral record. Back-scattering optical configuration is coupled with confocal collection of Raman signal of macro-sample in the high temperature shaft tube furnace. Results show that temperature-dependent Raman spectra can clearly indicate phase transition during melting. Relative densities of various kinds of SiO4(n-4) (n, bridging-oxygen number binding to one tetrahedron former Si) tetrahedrons can be qualitatively and quantitatively resolved by Gaussian spectral deconvolution. Obviously high temperature Raman spectroscopy provides an useful tool for the micro-structure research of materials under high temperature.

[The effect of whole pleural cavity irradiation with combined 60Co and electron beam plus local biological agents on malignant pleural effusion]

BACKGROUND

To study the effect and complications of combined 60Co γ ray and electron beam irradiation to malignant pleural effusion.

METHODS

From January,1996 to December,1998,55 patients with malignant pleural effusion (unilateral; 49 cases of primary lung cancer,4 breast cancer and 2 thymic tumor) received whole pleural cavity irradiation of 60Co γ ray with centrally placed lead blocks to protect the vital organs and normal lung tissue,and the electron beam irradiation at the area which was covered by lead blocks in 60Co γ ray irradiation.The pleural effusion was completely drained before radiotherapy,and dose distribution of middle level was calculated by TPS using EXT 2.4 version software (Multidata Co.USA).The 100% isodose curve was 2Gy,15 fractions were given and another 20Gy/10Fx irradiation was added to the visible tumor.All patients received sequential chemotherapy for 3-6 cycles (cisplatin-based regimens for lung cancer and thymic tumor,cyclophosphamide and adriamycin and fluoracil for breast cancer).Kaplan-Meier curve was used to evaluate the pleural effusion control rate and survival rate of patients.

RESULTS

Complete remission of the malignant pleural effusion was seen in 9 patients and partial in 46 when treatment completed.The 6-,12-,18-month pleural effusion control rate and survival rate of the patients were 76%,53%,44% and 64%,34%,26%,respectively.The median control time of effusion and survival time were 14 months (2-32 months) and 9 months (4-32 months) respectively.We did not find any abnormality in liver function as well as in kidney function before and after treatment.Myelosuppression was the main side effect after combined chemotherapy and radiotherapy.Nineteen patients suffered from acute oesophagitis in grade 1-2,and 3 serious pleural fibrosis.There was no acute irradiation pneumonitis.

CONCLUSIONS

The treatment for malignant pleural effusion with combined 60Co γ ray and electron beam irradiation is tolerable and effective in clinical use.

[Phase I clinical trial of dose escalation on three dimensional conformal radiation therapy for non-small cell lung cancer]

BACKGROUND

To establish the technique of 3-dimensional conformal radiation therapy (3DCRT) for non-small cell lung cancer (NSCLC) in stage II-IIIB,and to assess its acute side-effects and to obtain the maximum tolerance dose (MTD).

METHODS

From June,1999 to June,2000,38 cases of NSCLC in stage II-IIIB were enrolled in this study.MTD was identified by dose escalation study.After 42Gy/21Fx/4.2wks by conventional fractionated irradiation through AP/PA fields,which covered the primary tumor and lymph nodes,the technique of 3DCRT was used as boost.The boost fields encompassed the clinical lesions showed on chest CT.The planning of total dose escalation depended on the percentage,i.e.,<25%,25%-37%,and >37% of normal lung volume irradiated to over 20Gy.The scheduled dose escalation ranged from 69 to 81Gy.The criteria for stopping dose escalation was grade III or more worse radiation pneumonitis (RTOG).The boost doses were delivered with 3Gy/fraction,once a day,5 fractions a week.

RESULTS

Thirty-three cases had completed their treatments and could be evaluated by now.Acute radiation pneumonitis occurred in 26% of patients with grade I-II and 3% with grade III,and acute radiation esophagitis in 61% with grade I-II and 9% with grade III,and the hematopoietic toxicity in 58% with grade I-II and 9% with grade III.The current doses implemented were 78,78,and 75Gy respectively for patients with <25%,25%-37%,and >37% of normal lung volume irradiated.The overall immediate response rate of tumors was 88%(29/33).

CONCLUSIONS

Dose escalation in a volume-dependent organ as the lungs is acceptable and applicable.The immediate response is encouraging.MTD is to be determined.The long-term follow-up is needed to observe late complications and treatment efficacy.

[Chemotherapy combined with chest radiation therapy in the treatment of 95 patients with limited stage small cell lung cancer]

BACKGROUND

To analyse retrospectively the results and prognostic factors of 95 patients with limited stage small cell lung cancer treated with chemotherapy plus chest radiation therapy.

METHODS

Ninety-five patients with limited stage small cell lung cancer were treated with combination chemotherapy plus chest radiation therapy from December,1989 to June,1997.There were 84 males and 11 females with median age of 58 years (32-75 years).The P-TNM stages of the disease were as follows:stage I disease,3 patients; stage II disease,7 patients; stage IIIA disease,49 patients and stage IIIB disease,36 patients.Chemotherapy regimens were CAP (cyclophosphamide,doxorubicin,cisplatin),EP(etoposide,cisplatin),TP(Teniposide,cisplatin),or IEP (ifosphamide,etoposide,cisplatin).Median cycles were 6 (1-10).After one cycle of chemotherapy,patients received chest radiation therapy with median total tumor dose of 59.1Gy(43.8-76.9Gy)/31fx(22-64fx) for 48 days(30-73days).The radiation fields covered tumors with 1.5-2.0cm margins.Supraclavicular region and brain did not receive prophylactic irradiation.

RESULTS

Of the ninety-five patients,55(58%) had a complete response,36(38%) had a partial response,three had a stable disease and one had a disease progression.The median survival time was 28 months.The 1-,2-,3- and 5-year survival rates were 85%,62%,31% and 13%,respectively.The 1-,2-,3-,and 5-year local control rates were 95%,86%,77% and 64%,respectively.The 1-,2-,3- and 5-year distant metastasis rates were 23%,52%,73%,and 83%,respectively.From multivariate regression analyses,KPS≥70 and complete response and partial response could be the favorable predictors.

CONCLUSIONS

Chemotherapy combined with chest irradiation in limited stage small cell lung cancer can get better survival and local control and less distant metastases.KPS≥70 and complete response and partial response might be the favorable predictors.

A modified p53 overcomes mdm2-mediated oncogenic transformation: a potential cancer therapeutic agent

The antiproliferative activities of wild-type (wt) p53 are inhibited by mdm2 (murine double minute2) oncogene product. We tested growth suppression activity of p53 14/19, an engineered p53 variant, which does not bind mdm2 and is completely resistant to the inhibition by mdm2. p53 14/19, unlike wt p53, suppressed the growth of cancer cells that contain amplified mdm2 oncogene efficiently by direct DNA transfection or adenovirus-mediated gene transfer. In addition, p53 14/19 also inhibited the growth of several different cancer cell lines expressing low levels of mdm2 oncogene product as efficiently as wt p53. We further examined the antioncogenic potencies of p53 14/19 in the rat embryo fibroblast cotransformation assay. Addition of wt p53 failed to cause any significant decrease in ras plus mdm2 foci counts. In contrast, cotransfection of p53 14/19 with ras and mdm2 significantly reduced foci number. In similar experiments, cotransfection of wt p53 or 14/19 p53 resulted in significant inhibition of oncogenic transformation in rat embryo fibroblast mediated by an activated ras plus c-myc, adenovirus E1A, or human papillomavirus E7 oncogenes. Therefore, these results suggest that p53 14/19 modified tumor suppressor gene may be a promising therapeutic agent for human cancers that express abnormally high levels of mdm2 oncogene product.

[High temperature Raman spectra and micro-structure study of lithium metaborate and its melt]

Lithium metaborate (LiBO2) is studied by high temperature Raman spectroscopy from room temperature up to 1,673 K, and spectra drawing in different temperature are got. By analyzing, it focus on the phase transition, it is that the endless chains of BO3 triangles transform into rings of (B3O6)3- at about 1,123 K, and then the different kind of phase balance's motion occurs after 1,273 K which implies that both endless chain and ring have changed to CRN. In the drawing, the variation of peak's area rate implies the micro-structure information, and shows the process from order to disorder.

Analysis of protein dimerization and ligand binding of orphan receptor HNF4alpha

Hepatocyte nuclear factor 4alpha (HNF4alpha) (NR2A1), an orphan member of the nuclear receptor superfamily, binds DNA exclusively as a homodimer even though it is very similar in amino acid sequence to retinoid X receptor alpha (RXRalpha), which heterodimerizes readily with other receptors. Here, experimental analysis of residues involved in protein dimerization and studies on a reported ligand for HNF4alpha are combined with a structural model of the HNF4alpha ligand-binding domain (LBD) (residues 137 to 384). When K300 (in helix 9) and E327 (in helix 10) of HNF4alpha1 were converted to the analogous residues in RXRalpha (E390 and K417, respectively) the resulting construct did not heterodimerize with the wild-type HNF4alpha, although it was still able to form homodimers and bind DNA. Furthermore, the double mutant did not heterodimerize with RXR or RAR but was still able to dimerize in solution with an HNF4alpha construct truncated at amino acid residue 268. This suggests that the charge compatibility between helices 9 and 10 is necessary, but not sufficient, to determine dimerization partners, and that additional residues in the HNF4alpha LBD are also important in dimerization. The structural model of the HNF4alpha LBD and an amino acid sequence alignment of helices 9 and 10 in various HNF4 and other receptor genes indicates that a K(X)(26)E motif can be used to identify HNF4 genes from other organisms and that a (E/D(X)(26-29)K/R) motif can be used to predict heterodimerization of many, but not all, receptors with RXR. In vitro analysis of another HNF4alpha mutant construct indicates that helix 10 also plays a structural role in the conformational integrity of HNF4alpha. The structural model and experimental analysis indicate that fatty acyl CoA thioesters, the proposed HNF4alpha ligands, are not good candidates for a traditional ligand for HNF4alpha. Finally, these results provide insight into the mechanism of action of naturally occurring mutations in the human HNF4alpha gene found in patients with maturity onset diabetes of the young 1 (MODY1).

Sinorhizobium fredii USDA257, a cultivar-specific soybean symbiont, carries two copies of y4yA and y4yB, two open reading frames that are located in a region that encodes the type III protein secretion system

Sinorhizobium fredii USDA257 forms nitrogen-fixing nodules on primitive soybean (Glycine max) cultivar Peking but fails to nodulate the improved cultivar McCall. Cultivar specificity is governed by a plasmid-borne locus, nolXBTUV. By DNA sequence analysis, we have identified two open reading frames, y4yA and y4yB, immediately downstream of nolX. Northern (RNA) blot analysis indicated that the expression of both y4yA and y4yB is inducible by isoflavonoids, and an intact copy of nolX is required. Two copies each of y4yA and y4yB are present in S. fredii USDA257, one on the sym plasmid (y4yAsp and y4yBsp), and the other on the chromosome (y4yAc and y4yBc). The cultivar-nonspecific strain USDA191 lacks y4yAc and y4yBc. Introduction of y4yAc plus y4yBc from USDA257 into USDA191 did not influence the ability of the latter strain to nodulate McCall soybean plants. Unlike nolX, the inactivation of y4yAsp and y4yBsp of USDA257 did not extend the host range of this strain. A double mutant, in which both the plasmid and chromosomal copies of y4yA and y4yB were mutated, had no observable effect on symbiotic ability of USDA257. The y4yAsp and y4yBsp mutants did not influence flavonoid-dependent extracellular protein production. Rhizobium sp. strain NGR234 and S. saheli USDA4893 both contain sequences similar to S. fredii USDA257 y4yAsp and y4yBsp; however, Bradyrhizobium spp., the traditional soybean symbionts, lack these genes.