Tumor suppressor menin: the essential role of nuclear localization signal domains in coordinating gene expression

Menin is encoded by the tumor suppressor gene MEN1 that is mutated in patients with an inherited tumor syndrome, multiple endocrine neoplasia type 1 (MEN1). Although menin is a nuclear protein and directly binds to DNA through its nuclear localization signals (NLSs), the precise role for each of the NLSs in nuclear translocation and gene expression remains to be elucidated. Here, we show that point mutations in three individual NLSs, NLS1, NLS2, and a novel accessory NLS, NLSa, do not block nuclear translocation, but compromise the ability of menin to repress expression of the endogenous insulin-like growth factor binding protein-2 (IGFBP-2) gene. This repression is not released by an inhibitor of histone deacetylases. Although subtle mutations in menin NLSs do not affect menin association with chromatin, they abolish menin binding to the IGFBP-2 promoter in vivo. Furthermore, each of the NLSs is also crucial for menin-mediated induction of caspase 8 expression. Together, these results suggest that menin may act as a scaffold protein in coordinating activation and repression of gene transcription and that its NLSs play a more important role in controlling gene transcription than merely targeting menin into the nucleus.

An automatic approach for estimating bolus arrival time in dynamic contrast MRI using piecewise continuous regression models

We present two regression models for the automatic estimation of bolus arrival times (BATs) in dynamic contrast MRI datasets. Results of Monte Carlo simulation experiments show that the means and standard deviations of the estimated BATs are within the sampling interval even in the presence of significant noise.

A physiologic model of capillary-tissue exchange for dynamic contrast-enhanced imaging of tumor microcirculation

We present a multiple compartment, mammillary distributed-parameter model for capillary-tissue exchange, which can be implemented with dynamic contrast-enhanced imaging to study kinetic heterogeneity in tumors. The proposed n-compartment model consists of a vascular distributed-parameter compartment in direct exchange with a number (n - 1) of interstitial compartments. It is applied to a prostate tumor case study to illustrate the possible co-existence of two kinetically distinct compartments in the tumor, and the estimation of useful physiological parameters (such as perfusion, mean transit time, fractional volumes, and transfer and rate constants) associated with tissue microcirculation. The present model exhibits the convenient property of a separable impulse residue response function in time domain, which can be used to provide further insights and understanding on the physiological basis of tissue enhancement parameters commonly used for correlation studies with tumor histological diagnosis.

A numerical method for estimating blood flow by dynamic functional imaging

We present a numerical deconvolution scheme for estimating regional blood flow and tissue retention functions by dynamic functional imaging. The present approach implements the Tikhonov-Miller regularization in general form, which allows for prior knowledge or assumptions to be incorporated during the deconvolution process, so as to stabilize the solution against variations due to noise. Appropriate approximations and simplifications in the context of functional imaging, were also introduced to ease numerical computations. Monte Carlo simulation experiments were carried out to study the applicability of the present approach and to compare with other deconvolution techniques previously studied.

Experiences and lessons about soft-tissue flaps covering of severe open tibial fracture

OBJECTIVE

To sum up experiences and lessons ab out management of soft-tissue reconstruction in open tibial fracture over a 6-year period.

METHODS

Twenty-two flap reconstructions were performed to tre at soft-tissue defect of 22 patients with open tibial fracture Type IIIB (Gustilo) from 1993 to 1998. The cases were analyzed and discussed retrospectively aft er follow up of 12-61 months.

RESULTS

The size of the flap ranged from 6.6 cm(2) to 28.18 cm(2) and the rate of flap failure was 13.6%. Besides, 3 partial necrosis and 2 postoperative infections occurred in this series.

CONCLUSIONS

For soft tissue defect of delayed open tibial fracture Type IIIB, flap reconstruction is still an optimal option. The experiences we obtained are 1) to design a triangular skin extension or a small Z-plasty over the pedicle to reduce the flap tension; 2) to select a unilateral external fixation to provide convenience for any secondary manipulation; and 3) to use serial debridement to diminish flap failure.

[Cloning and biological regulating effects of human WAF1 gene]

OBJECTIVE

To clone human WAF1 gene and construct WAF1-pcDNA3 recombinant plasmid, and to explore the biological regulating effects of WAF1 gene.

METHODS

Human WAF1 gene was amplified and cloned into pcDNA3 vector by RT-PCR and DNA direct sequencing from Hela cells. By immunofluorescence and immunohistochemistry staining, the identify the expression of the inserted WAF1 gene and its biological regulating effects on Rb, cyclin D1 gene.

RESULTS

Human WAF1-pcDNA3 recombinant plasmid was correctly constructed and transfected into Hct-8 cells. P21WAFI/Clip was successfully expressed. The functional characterization of the inserting WAF1 gene implied that P21WAF1/Cip1 expression could upregulate Rb gene and downregulate cyclin D1 gene at protein level.

CONCLUSION

Human WAF1-pcDNA3 can modulate the protein expression of the downstream gene.

Synthesis of diphenylmethane from formalin and benzene in a biphasic system with 12-tungstophosphoric acid

Heteropoly acids such as H3PW12O40 are exceptionally active catalysts in the synthesis of diphenylmethane from benzene and formalin (aqueous formaldehyde) in a biphasic system and can be recycled simply by drying the aqueous phase at room temperature.

[The change of immunocompetent cells in normal human dental pulp during development of immature permanent teeth]

OBJECTIVE

To study changes of several immunocompetent cells (ICCs), namely, pulpal dendritic cells (PDCs), T lymphocytes, B lymphocytes, and endothelial cells, in normal human dental pulp according to different development stage of completely erupted but not fully developed premolar in order to provide evidence for local immune defense mechanisms during development of immature permanent teeth.

METHODS

Based on the dental development status, the pulp tissue was classified into the following groups: big trumped-shaped group, small trumped-shaped group and closed group. The above mentioned cells were immunohistochemically examined by use of HLA-DR, CD45RO, CD20 mouse anti-human monoclonal antibodies. Double-staining was also done by use of the former two antibodies. The number of positively stained cells or blood vessels was counted and statistically analyzed.

RESULTS

1. Normal dental tissue of three groups all expressed HLA-DR+ PDCs. Among three groups, the number of HLA-DR+ cells in big trumped-shaped group was more than that of small trumped-shaped group and closed group. 2. There was no significant difference of positive blood vessel rate of HLA-DR expressing endothelial cells among three groups. 3. There was no significant difference of CD45RO+ T cells among three groups. 4. By use of double-labeling immunohistochemistry, HLA-DR+ PDCs and CD45RO+ T cells were found to be rarely in contact with each other. Correlation analysis between two kinds of cells did not indicate the linear relationship.

CONCLUSIONS

The number of PDCs tends to decrease with increasing age in the developing dental pulp of human normal tooth, other ICCs are not related with dental development.

The RESID Database of protein structure modifications and the NRL-3D Sequence-Structure Database

The RESID Database is a comprehensive collection of annotations and structures for protein post-translational modifications including N-terminal, C-terminal and peptide chain cross-link modifications. The RESID Database includes systematic and frequently observed alternate names, Chemical Abstracts Service registry numbers, atomic formulas and weights, enzyme activities, taxonomic range, keywords, literature citations with database cross-references, structural diagrams and molecular models. The NRL-3D Sequence-Structure Database is derived from the three-dimensional structure of proteins deposited with the Research Collaboratory for Structural Bioinformatics Protein Data Bank. The NRL-3D Database includes standardized and frequently observed alternate names, sources, keywords, literature citations, experimental conditions and searchable sequences from model coordinates. These databases are freely accessible through the National Cancer Institute-Frederick Advanced Biomedical Computing Center at these web sites: http://www. ncifcrf.gov/RESID, http://www.ncifcrf.gov/NRL-3D; or at these National Biomedical Research Foundation Protein Information Resource web sites: http://pir.georgetown.edu/pirwww/dbinfo/resid .html, http://pir.georgetown.edu/pirwww/dbinfo/nrl3d .html

iProClass: an integrated, comprehensive and annotated protein classification database

The iProClass database is an integrated resource that provides comprehensive family relationships and structural and functional features of proteins, with rich links to various databases. It is extended from ProClass, a protein family database that integrates PIR superfamilies and PROSITE motifs. The iProClass currently consists of more than 200,000 non-redundant PIR and SWISS-PROT proteins organized with more than 28,000 superfamilies, 2600 domains, 1300 motifs, 280 post-translational modification sites and links to more than 30 databases of protein families, structures, functions, genes, genomes, literature and taxonomy. Protein and family summary reports provide rich annotations, including membership information with length, taxonomy and keyword statistics, full family relationships, comprehensive enzyme and PDB cross-references and graphical feature display. The database facilitates classification-driven annotation for protein sequence databases and complete genomes, and supports structural and functional genomic research. The iProClass is implemented in Oracle 8i object-relational system and available for sequence search and report retrieval at http://pir.georgetown.edu/iproclass/.

Protein Information Resource: a community resource for expert annotation of protein data

The Protein Information Resource, in collaboration with the Munich Information Center for Protein Sequences (MIPS) and the Japan International Protein Information Database (JIPID), produces the most comprehensive and expertly annotated protein sequence database in the public domain, the PIR-International Protein Sequence Database. To provide timely and high quality annotation and promote database interoperability, the PIR-International employs rule-based and classification-driven procedures based on controlled vocabulary and standard nomenclature and includes status tags to distinguish experimentally determined from predicted protein features. The database contains about 200,000 non-redundant protein sequences, which are classified into families and superfamilies and their domains and motifs identified. Entries are extensively cross-referenced to other sequence, classification, genome, structure and activity databases. The PIR web site features search engines that use sequence similarity and database annotation to facilitate the analysis and functional identification of proteins. The PIR-Inter-national databases and search tools are accessible on the PIR web site at http://pir.georgetown.edu/ and at the MIPS web site at http://www.mips.biochem.mpg.de. The PIR-International Protein Sequence Database and other files are also available by FTP.

Glycosylation-dependent cell adhesion molecule 1 (GlyCAM 1) is induced by prolactin and suppressed by progesterone in mammary epithelium

Glycosylation-dependent cell adhesion molecule 1 (GlyCAM 1), a mucin-like endothelial glycoprotein, was induced by PRL and suppressed by progesterone in the mammary gland of mice, and in HC11 mouse mammary epithelial cells. Complementary DNA microarray analysis revealed that expression of GlyCAM 1 was reduced in the mammary gland of PRL-gene disrupted mice (PRL-/-) compared with control (PRL+/-) littermates. This result was confirmed by in situ hybridization and immunostaining. The messenger RNA (mRNA) encoding GlyCAM 1 was present in mammary epithelia of PRL-stimulated mice. Immunohistochemistry indicated that GlyCAM 1 protein was detectable both in mammary epithelia and in the ductal lumen in PRL+/- virgin mice, but not in PRL-/- mice. GlyCAM 1 mRNA was highly induced by grafting pituitary glands from normal littermates. Trace amounts of mRNA for GlyCAM 1 were detected by RT-PCR in mammary tissue of PRL-/- mice. Progesterone inhibited both basal and PRL-stimulated GlyCAM 1 transcription. In HC11 cells, GlyCAM 1 mRNA was induced in cells treated with insulin, dexamethasone, and PRL. Similar to the in vivo studies, progesterone inhibited the induction of GlyCAM 1 transcription. In CHO cells, PRL stimulated transcription of a luciferase reporter gene containing an 800-bp promoter fragment of GlyCAM 1, and progesterone partially suppressed the PRL effect. These data demonstrate that expression of GlyCAM 1 in mammary gland is under the control of both PRL and progesterone.

Alkali and alkaline-earth metal ketyl complexes: isolation, structural diversity, and hydrogenation/protonation reactions

The use of hexamethylphosphoric triamide (HMPA) as a stabilizing ligand allowed successful isolation of a series of structurally characterizable alkali metal and calcium ketyl complexes. Reaction of lithium and sodium with one equivalent of fluorenone and reaction of sodium with one equivalent of benzophenone in THF, followed by addition of two equivalents of HMPA, yielded the corresponding ketyl complexes 1, 2, and 11, respectively, as microketyl-bridged dimers. If one equivalent of HMPA was used in the reaction of sodium with fluorenone, a further aggregated complex, the mu3-ketyl-bridged tetramer 3, was isolated, whereas analogous reaction of benzophenone with sodium afforded the trimeric ketyl complex 13, rather than a simple benzophenone analogue of 3. In the reaction of potassium with fluorenone, the use of two equivalents of HMPA gave the tetramer 4, rather than a dimeric complex analogous to 1 or 2. Compared to the tetrameric sodium complex 3, there is an extra HMPA ligand that bridges two of the four K atoms in 4. When 0.5 equiv of HMPA was used in the above reaction, complex 5, a THF-bridged analogue of 4, was isolated. In the absence of HMPA, the reaction of sodium with an excess of fluorenone yielded the tetrameric ketyl complex 6, in which two of the four Na atoms are each terminally coordinated by a fluorenone ligand, and the other two Na atoms are coordinated by a THF ligand. Two bridging THF ligands are also observed in 6. Reaction of 1,2-bis(biphenyl-2,2'-diyl)ethane-1,2-diol (7) with two equivalents of LiN(SiMe3)2 or NaN(SiMe3)2 in the presence of four equivalents of HMPA easily afforded 1 or 2, respectively, via C-C bond cleavage of a 1,2-diolate intermediate. The reaction of calcium with two equivalents of fluorenone or benzophenone in the presence of HMPA gave the corresponding complexes that bear two independent ketyl ligands per metal ion. In the presence of 3 or four equivalents of HMPA, the fluorenone ketyl complex was isolated in a six-coordinate octahedral form (10), while the benzophenone ketyl complex was obtained as a five-coordinate trigonal bipyramid (13). The radical carbon atoms in both benzophenone ketyl and fluorenone ketyl complexes are still in an sp2-hybrid state. However, in contrast with the planar configuration of the whole fluorenone ketyl unit, the radical carbon atom in a benzophenone ketyl species is not coplanar with any of the phenyl groups; this explains why benzophenone ketyl is more reactive than fluorenone ketyl. Hydrolysis of 2 or 11 with 2N HCI yielded the corresponding pinacol-coupling product, while treatment of 2 or 11 with 2-propanol, followed by hydrolysis, gave the pairs fluorenone and fluorenol or benzophenone and benzhydrol, respectively. A possible mechanism for these reactions is proposed.

Wide-range amplified spontaneous emission wavelength tuning in a solid-state dye waveguide

Amplified spontaneous emission (ASE) in an organic-dye- (DCM-) doped poly(methyl methacrylate)/silica-gel hybrid material planar waveguide was investigated. ASE wavelength control and tuning in a wedge waveguide were realized. The tuning range of the waveguide can reach as much as 30 nm. This method can be applied to wide-range wavelength tuning in solid-state tunable lasers.

[Effects of chincap therapy for early anterior crossbite]

OBJECTIVE

To analysis the effects of chincap therapy for early anterior crossbite and mandibular prognathism.

METHODS

136 patients anterior crossbite and mandibular prognathism aged from 3 to 14 years old at the start of treatment were treated with active chincap with bilateral force of 700 to 1000 gram. Every patient wore chin cap 12 to 14 hours daily, and most of those patients used removable appliances to open the crossbite of incisors. According to the age of patients, they were divided into four groups, C1 (3-5 years old), C2 (6-8 years old), C3 (9-11 years old) and C4 (12-14 years old). When the treatment ended after two years, we analyzed the models by measuring the length of maxillary on the models before and after treatment (U1 and U2 that's the distance between the tip of 1|1 and the distal plane of 6|6 or V|V and the overjet before and after treatment (L1 and L2). Then we calculated the obtained distance for the mandible related to the maxillary position X(X = (L2-L1)-(U2-U1)) and analyzed treating time and mandibular retreating speed in the four groups.

RESULTS

The obtained distance for the mandible related to the maxillary position in C1, C2, C3 and C4 groups were 3.27 +/- 0.99 mm, 4.62 +/- 1.33 mm, 4.43 +/- 1.28 mm and 2.63 +/- 0.92 mm respectively, and the treating time in four groups were 8.92 +/- 2.66 months, 10.47 +/- 2.21 months, 13.07 +/- 2.00 months, 20.50 +/- 3.96 months respectively. The retreating speed of the mandible related to the maxillary position in the four groups were 0.37 mm/month, 0.44 mm/month, 0.34 mm/month and 0.13 mm/month respectively. The effects of the treatment in C1, C2 and C3 groups (3-11 years old) were remarkable, especially in C1 group (3-5 years old).

CONCLUSION

The effects of chincap therapy for early anterior crossbite and mandibular prognathism were remarkable, especially for the very early crossbite patients.