Characterization of an oxygen-dependent inducible promoter, the nar promoter of Escherichia coli, to utilize in metabolic engineering

The nar promoters, whose transcription is maximally induced under microaerobic conditions in the presence of nitrate ion, were characterized in fed-batch culture to determine whether they can be used for metabolic engineering, by which overall production of valuable chemicals can be increased. For this purpose, we tested whether the expression level of a reporter gene, the lacZ gene from the nar promoter, could be maintained constant throughout the induction period by manipulation of dissolved oxygen (DO) levels at a given nitrate ion concentration. First, E. coli was grown under aerobic conditions (DO 80%) to absorbance at 600 nm (OD(600)) of 35, then the nar promoter was induced by reduction of DO to different levels, combined with different frequencies and duration of alternating microaerobic and aerobic conditions throughout the entire induction period. For a wild-type nar promoter (pMW61) in a mutant host E. coli with a mutation in the narG gene on the chromosome of the host (RK5265), it was possible to maintain production of beta-galactosidase activity per cell (specific beta-galactosidase activity) at a constant rate at 5000, 10,000, 15,000, and 20,000 Miller units, using different combinations of nitrate ion concentrations (0.1%, 0.5%, and 1%) and DO levels. In addition, it was possible to maintain production of specific beta-galactosidase activity at a constant rate at about 10,000 Miller units in the absence of nitrate ion when a nitrate-independent nar promoter (pMW618) in the narL(-) mutant of the W3110 E. coli strain (W3110narL(-)) was used. Based on these results, we conclude that the nar promoter system provides a convenient expression system for metabolic engineering as well as for maximal production of recombinant proteins under conditions of fed-batch culture.

[Anatomical study and clinical application of medial femoral condylar bone flap pedicled with the saphenous vessels]

OBJECTIVE

To investigate a new operative method for repairing nonunion and defect of tibia.

METHODS

First, observe the relation between the joint branches of descending genicular artery and the saphenous branch of descending genicular artery in 10 cadevers. Then the medial femoral condylar bone flap pedicled with the saphenous vessels was prepared in 4 cadavers for simulated purpose. Clinically, two patients with tibial nonunion were treated by transplantation of this pedicled bone flap.

RESULTS

In the 4 simulated operations, the ink which was injected into the femoral artery could be released from the joint branches. And in the clinical operation, the area of the pedicled bone flaps were 5.0 cm x 2.0 cm x 1.5 cm and 4.5 cm x 1.5 cm x 1.5 cm respectively. Followed up for 8 to 12 weeks, the fracture unioned well.

CONCLUSION

This operation is simple and reliable, it is characterised by 1. unnecessary to anastomosis the vessels 2. reliable blood supply 3. high quality of bone flap 4. either bone flap or bone-skin flap can be chosen 5. long vessel pedicle.

In vivo requirement of activator-specific binding targets of mediator

There has been no unequivocal demonstration that the activator binding targets identified in vitro play a key role in transcriptional activation in vivo. To examine whether activator-Mediator interactions are required for gene transcription under physiological conditions, we performed functional analyses with Mediator components that interact specifically with natural yeast activators. Different activators interact with Mediator via distinct binding targets. Deletion of a distinct activator binding region of Mediator completely compromised gene activation in vivo by some, but not all, transcriptional activators. These demonstrate that the activator-specific targets in Mediator are essential for transcriptional activation in living cells, but their requirement was affected by the nature of the activator-DNA interaction and the existence of a postrecruitment activation process.

REP1, a basic helix-loop-helix protein, is required for a branch pathway of phytochrome A signaling in arabidopsis

Phytochromes are primary photoreceptors mediating diverse responses ranging from induction of germination to floral induction in higher plants. We have isolated novel recessive rep1 (reduced phytochrome signaling 1) mutants, which exhibit a long-hypocotyl phenotype only under far-red light but not under red light. Physiological characterization showed that rep1 mutations greatly reduced a subset of phytochrome A-regulated responses, including the inhibition of hypocotyl elongation, cotyledon expansion, modulation of gravitropic growth of hypocotyl, and induction of the CAB (encoding chlorophyll a/b binding protein) gene, without affecting the accumulation of anthocyanin, far-red-preconditioned blocking of greening, induction of germination, and induction of CHS (encoding chalcone synthase) and FNR (encoding ferredoxin-NADP(+) oxidoreductase) genes. These results suggest that REP1 is a positive signaling component, functioning in a branch of the phytochrome A signaling pathway. Molecular cloning and characterization of the REP1 gene revealed that it encodes a light-inducible, putative transcription factor containing the basic helix-loop-helix motif.

Gram-negative bacteria-binding protein, a pattern recognition receptor for lipopolysaccharide and beta-1,3-glucan that mediates the signaling for the induction of innate immune genes in Drosophila melanogaster cells

Pattern recognition receptors, non-clonal immune proteins recognizing common microbial components, are critical for non-self recognition and the subsequent induction of Rel/NF-kappaB-controlled innate immune genes. However, the molecular identities of such receptors are still obscure. Here, we present data showing that Drosophila possesses at least three cDNAs encoding members of the Gram-negative bacteria-binding protein (DGNBP) family, one of which, DGNBP-1, has been characterized. Western blot, flow cytometric, and confocal laser microscopic analyses demonstrate that DGNBP-1 exists in both a soluble and a glycosylphosphatidylinositol-anchored membrane form in culture medium supernatant and on Drosophila immunocompetent cells, respectively. DGNBP-1 has a high affinity to microbial immune elicitors such as lipopolysaccharide (LPS) and beta-1,3-glucan whereas no binding affinity is detected with peptidoglycan, beta-1,4-glucan, or chitin. Importantly, the overexpression of DGNBP-1 in Drosophila immunocompetent cells enhances LPS- and beta-1,3-glucan-induced innate immune gene (NF-kappaB-dependent antimicrobial peptide gene) expression, which can be specifically blocked by pretreatment with anti-DGNBP-1 antibody. These results suggest that DGNBP-1 functions as a pattern recognition receptor for LPS from Gram-negative bacteria and beta-1, 3-glucan from fungi and plays an important role in non-self recognition and the subsequent immune signal transmission for the induction of antimicrobial peptide genes in the Drosophila innate immune system.

Selective involvement of reactive oxygen intermediates in platelet-activating factor-mediated activation of NF-kappaB

Although it has been suggested that some biological activities of platelet-activating factor (PAF) are mediated by, at least in part, reactive oxygen intermediates (ROI), the precise mechanisms underlying the interaction between the two remains to be elucidated. Antioxidants, such as alpha-tocopherol acid succinate, N-acetyl-L-Cysteine, pyrrolidinedithiocarbamate failed to inhibit PAF-induced immediate systemic reactions such as lethality, symptoms of disseminated intravascular coagulation, and histological changes such as pulmonary edema and hemorrhage in renal medullae 10 min following PAF injection. In contrast. antioxidants significantly inhibited both the in vivo and in vitro PAF-induced NF-kappaB activation and NF-kappaB-dependent TNF-alpha expression. The effects of the antioxidants were due to their inhibition of PAF-induced degradation of IkappaBalpha, a protein responsible for keeping NF-kappaB in an inactive form. A protein tyrosine kinase and N-tosyl-L-phenylalanine chloromethyl ketone sensitive serine protease were involved in both PAF- and H2O2-induced NF-kappaB activation. Collectively, these data indicate that the PAF-induced NF-kappaB activation is selectively mediated through the generation of ROI.

Viscosity of Nonionic Polymer/Anionic Surfactant Complexes in Water

The polymer-micelle model, formerly established by Cabane, is revised to develop a new viscosity equation to describe the dependence of dilute solution viscosity on polymer concentration in PEG/SDS aqueous solutions. Two parameters inthe new equation were proposed to characterize the influence of the polymer solution viscosity on the added surfactant. The viscosity data of polyethylene glycol (PEG) solutions containing sodium dodecyl sulfate (SDS) were measured by the Ubbelohde dilution viscometer and the new equation proved to be in good agreement with the experimental data. Copyright 2000 Academic Press.

Behavior of lanthanides in countercurrent chromatography using dihexyl-N,N-diethylcarbamoyl methylene phosphonate as stationary phase

Counter-current chromatography is a real liquid-liquid chromatography. The retention volume of the solute can be calculated from the batch distribution ratio in organic separations. In the separations of metal ion, there are several complex and dissociation reactions involved in the two phases, and the retention volume cannot be always predicted from the batch distribution ratio. A mass transfer model is proposed in this paper and an expression of V(R) is derived. The retention volume of metal ion is determined not only by the batch distribution ratio but also by the mechanism of the extraction reaction. When 25% dihexyl-N,N-diethylcarbamoyl methylenephosphonate in cyclohexane is used as stationary phase and 2.91 mol/l HNO3 as mobile phase, the dynamic distribution ratios obtained from the chromatogram are not equal to but proportional to the batch distribution coefficients. These results are in agreement with the theoretical expression.

Inhibition of mitogen-activated protein kinase by a Drosophila dual-specific phosphatase

The Drosophila extracellular signal-regulated kinase (DERK) mitogen-activated protein kinase (MAPK) is involved in the regulation of multiple differentiation and developmental processes. Tight control of MAPK activity is critical for normal cell behaviour. We identified a novel Drosophila MAPK phosphatase (DMKP) cDNA from the expressed-sequence-tag database and characterized it. Analysis of the nucleotide sequence revealed an open reading frame encoding the 203-amino acid protein, with a calculated molecular mass of 23 kDa, which has a high amino acid sequence similarity with 'VH1-like' dual-specific phosphatases at the broad region near the catalytic sites. The expression of DMKP mRNA occurs from the late larval stages to adulthood in Drosophila development. The recombinant DMKP protein produced in yeast retained its phosphatase activity. When expressed in Schneider cells, DMKP dose-dependently inhibited DERK and Drosophila c-Jun N-terminal kinase activities with high selectivity towards DERK. However, DMKP did not have any affect on Drosophila p38 activity. When DMKP was expressed in yeast, it down-regulated the fus1-lacZ trans-reporter gene of the pheromone MAPK pathway without any significant effect on the high-osmolarity-glycerol-response pathway.

Conformational study of asialo-GM1 (GA1) ganglioside

In order to investigate the significance of preferred conformations of the saccharide for the steric orientation and recognition of glycosphingolipids at the membrane surface, the conformational free energy calculations were carried out on the asialo-GM1 [GA1; beta-D-Gal (1-->3) beta-D-GalNac(1-->4) beta-D-Gal(1-->4) beta-D-Glc-O-ceramide) using a new program CONCARB (CONformational study program for CARBohydrate) in the unhydrated and hydrated states. The overall backbone conformational of GA1 appears to be extended with a little bent at the glycosidic II-III linkage, in which two pyranose rings of Gal(IV)-GalNAc-(III) moiety orient approximately perpendicular to those of Gal(II)-Glc(I) moiety. This is consistent with the structures deduced from high-sensitivity differential scanning calorimetry experiments and the nmr study on GA1. The calculated glycosidic torsion angles of the lowest free energy conformation of GA1 in the hydrated state are in accord with the structures of relevant oligosaccharides deduced from nmr experiments and hard sphere exoanomeric calculations. A comparison of the values of glycosidic torsion angles phi and psi of GA1 and its constituent oligosaccharides indicates that the overall backbone conformation of each oligosaccharide is retained when the oligosaccharide chain becomes longer. This implies that the short-range interactions between the nearest-neighbored saccharides are of significant importance in stabilizing the overall backbone conformation of GA1 in both the unhydrated and hydrated states. The different orientation and hydrogen bonds of hydroxymethyl and hydroxyl groups from one oligosaccharide to another suggest that the medium- and long-range interactions are also of consequence. Hydration seems to affect significantly the confirmation of these groups, but not to perturb remarkably the overall backbone conformation of GA1.

Biliary atresia in neonates and infants: triangular area of high signal intensity in the porta hepatis at T2-weighted MR cholangiography with US and histopathologic correlation

PURPOSE

To correlate a triangular area of high signal intensity in the porta hepatis on T2-weighted magnetic resonance (MR) cholangiograms of biliary atresia with ultrasonographic (US) and histopathologic findings in a portal mass observed during a Kasai procedure.

MATERIALS AND METHODS

Twenty-one consecutive neonates and infants (age range, 13-88 days; mean age, 59 days) with cholestasis underwent US and single-shot MR cholangiography. In 12 patients with biliary atresia diagnosed at histopathologic examination, MR cholangiographic findings in the porta hepatis were correlated with US and histopathologic findings in the portal mass.

RESULTS

At US, eight of the 12 patients had round, linear, or tubular hypoechoic portions within a triangular cord; MR cholangiography revealed a triangular area of high signal intensity confined to the porta hepatis. Histopathologic examination of the portal mass revealed a cystic or cleftlike lesion surrounded by loose myxoid mesenchyme and platelike fetal bile ducts. Neither the large cystic lesion without ductal epithelium nor the small cleftlike lesion with scanty epithelium demonstrated bile staining. Similar areas of high signal intensity were not seen on T2-weighted images in the remaining patients (four with biliary atresia and nine with neonatal hepatitis).

CONCLUSION

In biliary atresia, T2-weighted single-shot MR cholangiography can show a triangular area of high signal intensity in the porta hepatis that may represent cystic dilatation of the fetal bile duct.

Development and characterization of an oxygen-dependent inducible promoter system, the modified nar promoter in a mutant Escherichia coli

A nar promoter system (a modified nar promoter in a mutant host Escherichia coli (pMW618/W3110narL(-))), which is maximally induced under microaerobic conditions, was developed and characterized through batch and fed-batch culture to see whether the modified nar promoter can be used as an oxygen-dependent inducible promoter in the absence of nitrate ion. The modified nar promoter (pMW618) derived by mutations at -10 and -35 regions of the wild-type nar promoter does not require nitrate ion for the full induction, while a mutant host E. coli, W3110narL(-), does not express nitrate-dependent regulatory protein, NARL, from the host chromosome. In this study, it was found from fed-batch culture that the specific beta-galactosidase activity expressed from the lacZ gene fused to the modified nar promoter in the absence of nitrate ion was maximal when E. coli was grown under aerobic conditions (dissolved oxygen (DO) at 80%) to absorbance at 600 nm (OD(600)) of 35, and then the modified nar promoter was induced by lowering DO to 1-2% with alternating microaerobic and aerobic conditions. The maximal specific beta-galactosidase activity became 58,000 Miller at OD(600) of 160 with an induction ratio of 20. On the basis of these results, we conclude that the modified nar promoter system (pMW618/W3110narL(-)), requiring only reduction of DO for the full induction, provides a convenient and effective high-level expression system under conditions of fed-batch culture.

Lipopolysaccharide-activated kinase, an essential component for the induction of the antimicrobial peptide genes in Drosophila melanogaster cells

Eukaryotic organisms use a similar Rel/NF-kappaB signaling cascade for the induction of innate immune genes. In Drosophila, lipopolysaccharide (LPS) signal-induced activation of the Rel/NF-kappaB family transcription factors is an essential step in the transcriptional activation of inducible antimicrobial peptide genes. However, the mechanism by which the LPS-induced signaling pathway proceeds remains largely unknown. Here we have cloned a novel Drosophila LPS-activated kinase (DLAK) that is structurally related to mammalian IkappaB kinases. DLAK is expressed and transiently activated in LPS-responsive Drosophila cells following LPS stimulation. Furthermore, DLAK can interact with Cactus, a Drosophila IkappaB and phosphorylate recombinant Cactus, in vitro. Overexpression of dominant-negative mutant DLAK (DLAK(K50A)) blocks LPS-induced Cactus degradation. DLAK-bound Cactus can be degraded in a LPS signal-dependent fashion, whereas the DLAK(K50A) mutant-bound Cactus is completely resistant to degradation in the presence of LPS. The DLAK(K50A) mutant also inhibits nuclear kappaB binding activity and kappaB-dependent diptericin reporter gene activity in a dose-dependent manner, but the kappaB-dependent diptericin reporter gene activity can be rescued by overexpression of wild type DLAK. Moreover, mRNA analysis of various kappaB-dependent antimicrobial peptide genes shows that LPS inducibility of these genes is greatly impaired in cells overexpressing DLAK(K50A). These results establish that DLAK is a novel LPS-activated kinase, which is an essential signaling component for the induction of antimicrobial peptide genes following LPS treatment in Drosophila cells.

Caenorhabditis elegans mediator complexes are required for developmental-specific transcriptional activation

Mediator proteins are required for transcriptional regulation of most genes in yeast. Mammalian Mediator homologs also function as transcriptional coactivators in vitro; however, their physiological role in gene-specific transcription is not yet known. To determine the role of Mediator proteins in the development of complex organisms, we purified putative Mediator complexes from Caenorhabditis elegans and analyzed their phenotypes in vivo. C. elegans Mediator homologs were assembled into two multiprotein complexes. RNA interference assays showed that the CeMed6, CeMed7, and CeMed10/CeNut2 gene products are required for the expression of developmentally regulated genes, but are dispensable for expression of the ubiquitously expressed genes tested in this study. Therefore, the gene-specific function of Mediator as an integrator of transcriptional regulatory signals is evolutionarily conserved and is essential for C. elegans development.

Genomic structure and ecdysone regulation of the prophenoloxidase 1 gene in the malaria vector Anopheles gambiae

Prophenoloxidase, a melanin-synthesizing enzyme, is considered to be an important arthropod immune protein. In mosquitoes, prophenoloxidase has been shown to be involved in refractory mechanisms against malaria parasites. In our study we used Anopheles gambiae, the most important human malaria vector, to characterize the first arthropod prophenoloxidase gene at the genomic level. The complete nucleotide sequence, including the immediate 5' flanking sequence (-855 bp) of the prophenoloxidase 1 gene, was determined. The gene spans 10 kb and is composed of five exons and four introns coding for a 2.5-kb mRNA. In the 5' flanking sequence, we found several putative regulatory motifs, two of which were identified as ecdysteroid regulatory elements. Electrophoretic mobility gel-shift assays and supershift assays demonstrated that the Aedes aegypti ecdysone receptor/Ultraspiracle nuclear receptor complex, and, seemingly, the endogenous Anopheles gambiae nuclear receptor complex, was able to bind one of the ecdysteroid response elements. Furthermore, 20-hydroxyecdysone stimulation was shown to up-regulate the transcription of the prophenoloxidase 1 gene in an A. gambiae cell line.

Interleukin (IL)-5 downregulates tumor necrosis factor (TNF)-induced eotaxin messenger RNA (mRNA) expression in eosinophils. Induction of eotaxin mRNA by TNF and IL-5 in eosinophils

An eotaxin is a chemoattractant specific for eosinophils that are known to play a role in helminth infection and allergic responses. Although several cellular sources have been reported to produce eotaxin, it would be interesting to know whether eosinophils are able to produce their own eotaxin and participate in recruitment of themselves in response to inflammation. To this end, a cloned eotaxin complementary DNA was transcribed in vitro to use as a probe for detecting eotaxin messenger RNA (mRNA), and eotaxin protein levels were determined by enzyme-linked immunosorbent assay. Eotaxin mRNA was, as analyzed by in situ hybridization, rarely detectable in unstimulated eosinophils, but was strongly induced in eosinophils when stimulated with tumor necrosis factor (TNF). Interleukin (IL)-5, which is known to be a major factor of eosinophil survival in vivo and in vitro, was also able to induce a modest level of eotaxin mRNA but inhibited TNF-induced eotaxin mRNA expression in a dose-response manner. Dexamethasone inhibited TNF-induced eotaxin mRNA expression. This result was consistent with that from reverse transcription/polymerase chain reaction followed by Southern blot analysis. Unlike the little expression of eotaxin mRNA in the absence of stimuli, the measurement of eotaxin protein revealed that a considerable amount of eotaxin protein was constitutively produced in unstimulated eosinophils. Its expression was upregulated by TNF and IL-5 as well. However, the inhibitory effect of IL-5 on TNF-mediated eotaxin protein production was not as pronounced as that on eotaxin mRNA induction. Collectively, these data reflect the complex physiology of eosinophils in the expression of eotaxin gene upon the exposure to their survival and/or death factors.

Gene silencing-mediated resistance in transgenic tobacco plants carrying potato virus Y coat protein gene

Unlike other pathogens, plant viruses are hardly controlled by chemical agents. Potato virus Y (PVY) is distributed around the world, and causes a great loss economically. In an attempt to minimize the damage by viruses, the PVY coat protein (CP) gene was introduced into tobacco by Agrobacterium-mediated transformation. A significant proportion of the transgenic plants displayed resistance to PVY and showed substantially decreased CP transgene expression at both protein and steady-state mRNA levels compared to susceptible transgenic or nontransgenic plants. A resistant plant was selected and self-fertilized for several generations until T4 progenitor lines were obtained. Most of these T4 plants accumulated extremely low levels of CP protein and steady-state mRNA, and exhibited almost complete resistance to PVY. DNA gel blot analysis revealed that the transgenic plants typically had two or three copies of the transgene. These results are characteristic of pathogen-derived resistance, in which the resistance against virus is the consequence of post-transcriptional gene silencing directed by homologous transgenes. To uncover factors that may play roles in gene silencing, sequences in the 3' part of the transcribed region of the CP gene were transcribed in vitro and the RNA fragments were incubated with cell extracts from transgenic plants. A ribonuclease activity was detected that appeared to be specific for this transcript in the PVY-resistant transgenic plants.

Glucocorticoids prevent NF-kappaB activation by inhibiting the early release of platelet-activating factor in response to lipopolysaccharide

Lipopolysaccharide (LPS) is a known inducer of numerous pro-inflammatory events including the production of platelet-activating factor (PAF). PAF released in response to LPS is a major contributor to the pathological events associated with endotoxemia. The present study demonstrates that dexmethasone (DEX) inhibited the LPS-induced early plasma PAF raise in a dose- and time-dependent manner. In addition, DEX prevented the subsequent PAF-mediated pathological phenomena such as anaphylactic shock-like symptoms, symptoms of disseminated intravascular coagulation and hemorrhage in renal medullae. DEX or the PAF antagonist BN 50739 significantly inhibited LPS-induced NF-kappaB activation. The inhibition of NF-kappaB activation by DEX was overcome by the injection of exogenous PAF. Administration of PAF or LPS resulted in a rapid loss of IkappaBalpha protein. The LPS-induced degradation of IkappaBalpha was prevented by pretreatment with BN 50739, suggesting that PAF is a critical intermediate in the LPS-triggered degradation of IkappaBalpha protein. DEX prevented the LPS-induced IkappaBalpha degradation, which was also reversed by exogenous PAF. Administration of DEX or BN 50739 caused an increase in cytoplasmic IkappaBalpha level. Our results indicate that DEX inhibits IkappaBalpha degradation and subsequent NF-kappaB activation through blocking the initial release of PAF.

An activator binding module of yeast RNA polymerase II holoenzyme

The Mediator complex of Saccharomyces cerevisiae is required for both general and regulated transcription of RNA polymerase II (PolII) and is composed of two stable subcomplexes (Srb4 and Rgr1 subcomplexes). To decipher the function of each Mediator subcomplex and to delineate the functional relationship between the subcomplexes, we characterized the compositions and biochemical activities of PolII-Mediator complexes (holoenzymes) prepared from several Mediator mutant strains of S. cerevisiae. We found that holoenzymes devoid of a functional Gal11 module were defective for activated but not basal transcription in a reconstituted in vitro system. This activation-specific defect was correlated with a crippled physical interaction to transcriptional activator proteins, which could be bypassed by artificial recruitment of a mutant holoenzyme to a promoter. Consistent with this observation, a direct interaction between Gal11 and gene-specific transcriptional activator proteins was detected by far-Western analyses and column binding assays. In contrast, the srb5 deletion mutant holoenzyme was defective for both basal and activated transcription, despite its capacity for activator binding that is comparable to that of the wild-type holoenzyme. These results demonstrate that the Gal11 module of the Rgr1 subcomplex is required for the efficient recruitment of PolII holoenzyme to a promoter via activator-specific interactions, while the Srb4 subcomplex functions in the modulation of general polymerase activity.

Glucocorticoids prevent NF-kappaB activation by inhibiting the early release of platelet-activating factor in response to lipopolysaccharide

Lipopolysaccharide (LPS) is a known inducer of numerous pro-inflammatory events including the production of platelet-activating factor (PAF). PAF released in response to LPS is a major contributor to the pathological events associated with endotoxemia. The present study demonstrates that dexmethasone (DEX) inhibited the LPS-induced early plasma PAF raise in a dose- and time-dependent manner. In addition, DEX prevented the subsequent PAF-mediated pathological phenomena such as anaphylactic shock-like symptoms, symptoms of disseminated intravascular coagulation and hemorrhage in renal medullae. DEX or the PAF antagonist BN 50739 significantly inhibited LPS-induced NF-kappaB activation. The inhibition of NF-kappaB activation by DEX was overcome by the injection of exogenous PAF. Administration of PAF or LPS resulted in a rapid loss of IkappaBalpha protein. The LPS-induced degradation of IkappaBalpha was prevented by pretreatment with BN 50739, suggesting that PAF is a critical intermediate in the LPS-triggered degradation of IkappaBalpha protein. DEX prevented the LPS-induced IkappaBalpha degradation, which was also reversed by exogenous PAF. Administration of DEX or BN 50739 caused an increase in cytoplasmic IkappaBalpha level. Our results indicate that DEX inhibits IkappaBalpha degradation and subsequent NF-kappaB activation through blocking the initial release of PAF.

Retinoids inhibit interleukin-12 production in macrophages through physical associations of retinoid X receptor and NFkappaB

Lipopolysaccharide (LPS) increases the production of interleukin-12 (IL-12) from mouse macrophages via a kappaB site within the IL-12 p40 promoter. In this study, we found that retinoids inhibit this LPS-stimulated production of IL-12 in a dose-dependent manner. The NFkappaB components p50 and p65 bound retinoid X receptor (RXR) in a ligand-independent manner in vitro, and the interaction interfaces involved the p50 residues 1-245, the p65 residues 194-441, and the N-terminal A/B/C domains of RXR. Activation of macrophages by LPS resulted in markedly enhanced binding activities to the kappaB site, which significantly decreased upon addition of retinoids, as demonstrated by the electrophoretic mobility shift assays. In cotransfections of CV-1 and HeLa cells, RXR also inhibited the NFkappaB transactivation in a ligand-dependent manner, whereas a mutant RXR lacking the AF2 transactivation domain, which serves as ligand-dependent binding sites for transcription integrators SRC-1 and p300, was without any effect. In addition, coexpression of increasing amounts of SRC-1 or p300 relieved the retinoid-mediated inhibition of the NFkappaB transactivation. From these results, we propose that retinoid-mediated suppression of the IL-12 production from LPS-activated macrophages may involve both inhibition of the NFkappaB-DNA interactions and competitive recruitment of transcription integrators between NFkappaB and RXR.

Multiple intestinal ulcerations and perforations secondary to methicillin-resistant Staphylococcus aureus enteritis in infants

PURPOSE

The aim of this study was to define a distinctive clinical entity of multiple intestinal ulcerations and perforations in infants.

METHODS

Two infants underwent abdominal exploration for surgical abdomen and were noted to have multiple intestinal ulcerations and perforations. A peculiar and unique surgical finding, numerous transverse linear ulcerations scattered along the entire small intestine, prompted us to search for similar instances. Five similar cases were additionally identified by members of the Korean Association of Pediatric Surgeons. The clinical courses, the surgical findings, and the results of bacterial cultures were reviewed. As well, the tissues of resected intestines were examined histopathologically.

RESULTS

The characteristics of this entity are as follows. (1) It usually occurs in infants who have been treated with broad-spectrum antibiotics. (2) Despite broad-spectrum antibiotic treatment, diarrhea and abdominal distension developed progressively and deteriorated. (3) Histological evaluation showed mucosal ulcers with neutrophil infiltration, submucosal microabscesses, and colonies of Gram-positive cocci. (4) Methicillin-resistant Staphylococcus aureus (MRSA) was the predominant organism cultured from the body fluid. (5) Only two cases, the completely resected one and the one immediately treated postoperatively with vancomycin, survived.

CONCLUSIONS

This entity is caused by multiple intestinal ulcerations and perforations secondary to MRSA enteritis in infants. It has a high mortality rate because of its difficult diagnosis. However, early recognition of this entity can lead to successful treatment.

Activator-specific requirement of yeast mediator proteins for RNA polymerase II transcriptional activation

The multisubunit Mediator complex of Saccharomyces cerevisiae is required for most RNA polymerase II (Pol II) transcription. The Mediator complex is composed of two subcomplexes, the Rgr1 and Srb4 subcomplexes, which appear to function in the reception of activator signals and the subsequent modulation of Pol II activity, respectively. In order to determine the precise composition of the Mediator complex and to explore the specific role of each Mediator protein, our goal was to identify all of the Mediator components. To this end, we cloned three previously unidentified Mediator subunits, Med9/Cse2, Med10/Nut2, and Med11, and isolated mutant forms of each of them to analyze their transcriptional defects. Differential display and Northern analyses of mRNAs from wild-type and Mediator mutant cells demonstrated an activator-specific requirement for each Mediator subunit. Med9/Cse2 and Med10/Nut2 were required, respectively, for Bas1/Bas2- and Gcn4-mediated transcription of amino acid biosynthetic genes. Gal11 was required for Gal4- and Rap1-mediated transcriptional activation. Med11 was also required specifically for MFalpha1 transcription. On the other hand, Med6 was required for all of these transcriptional activation processes. These results suggest that distinct Mediator proteins in the Rgr1 subcomplex are required for activator-specific transcriptional activation and that the activation signals mediated by these Mediator proteins converge on Med6 (or the Srb4 subcomplex) to modulate Pol II activity.

Expression of bvgAS of Bordetella pertussis represses flagellar biosynthesis of Escherichia coli

BvgAS is a two-component system of Bordetella pertussis involved in the reciprocal regulation of the virulence genes and the flagellar biosynthesis. In this study, we found that expression of bvgAS in Escherichia coli also results in reduced motility. The repression was relieved by the addition of known chemical modulators of BvgAS such as MgSO4 and nicotinic acid, indicating that functional BvgAS proteins are required for the negative control of E. coli motility. In addition, BvgAS repressed the transcription of the flhDC master operon of E. coli, which consequently caused non-flagellation on the cell surface. However, expression of BvgAS had no effect on stress-resistant motile mutants of E. coli. These data suggest that E. coli may have BvgA-like protein(s) involved in the regulatory interactions between the stress response and the flagellar biosynthesis.

Conformational study of Ac-Xaa-Pro-NHMe dipeptides: proline puckering and trans/cis imide bond

The conformational study on 20 Ac-Xaa-Pro-NHMe dipeptides has been carried out using an empirical potential function ECEPP/3 in order to investigate the factors responsible for the preference of proline puckering of the peptides with the trans or cis imide bond preceding the proline. The general conformational preference for down- and up-puckered dipeptides is calculated as trans-down > trans-up > cis-down > cis-up, which is reasonably in accord with that estimated by analyzing X-ray structures of proteins and the result for the single proline residue. The overestimated occurrence of trans-down conformations of proline seems to be caused by excluding long-range interactions that short dipeptides cannot have. The average computed occurrence of dipeptides with cis imide bonds is about 3%, somewhat lower than the value calculated for Ac-Pro-NHMe, which is close to experimental estimates obtained from X-ray structures of proteins. In particular, the interaction of the aromatic side chain of Xaa residue with the proline ring appears not to be strong enough to stabilize the stacked conformations of small dipeptides with cis imide bonds. The propensity to adopt trans or cis imide bond and to form secondary structures of Xaa-Pro sequences is discussed and compared with results obtained from X-ray structures of proteins.

Colon perforation in hyperimmunoglobulin E syndrome

Colon perforation from hyperimmunoglobulin E syndrome is very rare, and only one case has been reported in the English-language literature. Herein, the authors report another case of colon perforation experienced in hyperimmunoglobulin E syndrome. The patient was an 8-year-old girl with frequent infection, eczematoid dermatitis, and an increased serum level of immunoglobulin E. During admission, panperitonitis developed caused by colon perforation. Treatment was resection of the perforated segment of the colon and a double-barrel colostomy. The patient has been doing well 18 months after treatment.

Fed-batch cultivation of an oxygen-dependent inducible promoter system, the nar promoter in Escherichia coli with an inactivated nar operon

The nar promoter of Escherichia coli is maximally induced under anaerobic or microaerobic conditions in the presence of nitrate. We previously demonstrated in batch experiments that the intact nar promoter of E. coli cloned into a pBR322-based plasmid serves as a high-level expression system in a nar mutant of E. coli (Lee et al., 1996b). In this study, we extend characterization of the nar promoter expression system to the fed-batch culture mode, which is widely used in industrial-scale fermentation. From these experiments, it was found that the specific beta-galactosidase activity expressed from the lacZ gene fused to the nar promoter was maximal when host cells were grown under aerobic conditions [dissolved oxygen, (DO) = 80%] to absorbance at 600 nm (OD600) = 35 before induction of the nar promoter by lowering DO to 1-2% with alternating microaerobic and aerobic conditions. Approximately 15 h after induction, the OD600 of the culture reached 135 and the specific beta-galactosidase activity increased to 40,000 Miller units, equivalent to approximately 35% of the total cellular proteins. The specific beta-galactosidase activity before induction was approximately 1,000 Miller units, giving an induction ratio of approximately 40. Based on these results, we conclude that the nar promoter provides a convenient and effective high level expression system under conditions of fed-batch culture.

Steroid receptor coactivator-1 interacts with the p50 subunit and coactivates nuclear factor kappaB-mediated transactivations

Steroid receptor coactivator-1 (SRC-1) specifically bound to the transcription factor NFkappaB subunit p50 but not to p65 as demonstrated by the yeast two hybrid tests and glutathione S-transferase pull down assays. The p50-binding site was localized to a subregion of SRC-1 (amino acids 759-1141) that encompasses the previously described CBP-p300-binding domain. In mammalian cells, SRC-1 potentiated the NFkappaB-mediated transactivations in a dose-dependent manner. Coexpression of p300 further enhanced this SRC-1-potentiated level of transactivations, consistent with the recent findings in which CBP and p300 were shown to be transcription coactivators of the p65 subunit (Perkins, N. D., Felzien, L. K., Betts, J. C., Leung, K., Beach, D. H., and Nabel, G. J. (1997) Science 275, 523-527; Gerritsen, M. E., Williams, A. J., Neish, A. S. , Moore, S., Shi, Y., and Collins, T. (1997) Proc. Acad. Natl. Sci. U. S. A. 94, 2927-2932). These results suggest that at least two distinct coactivator molecules may cooperate to regulate the NFkappaB-dependent transactivations in vivo and SRC-1, originally identified as a coactivator for the nuclear receptors, may constitute a more widely used coactivation complex.

Interaction of phospholipase C gamma 1 via its COOH-terminal SRC homology 2 domain with synaptojanin

The role of the phospholipase C gamma 1 (PLC gamma 1) in signal transduction was investigated by characterizing its interactions with proteins that may represent components of a novel signalling pathway. A 145-kDa protein that binds SH2 domain of PLC gamma 1 was purified from rat brain. The sequence of peptide derived from the purified binding protein now identify it as synaptojanin, a nerve terminal protein that has been implicated in the endocytosis of fused synaptic vesicles and shown to be a member of the inositol polyphosphate 5-phosphatase family. We demonstrate here stable association of PLC gamma 1 with synaptojanin, a protein that not only binds carboxyl terminal SH2 domain of PLC gamma 1, but also inhibits PLC gamma 1 activity.

Infantile hemangioendothelioma with a highly elevated serum alpha-fetoprotein level

Infantile hemangioendothelioma is the most common vascular tumor in infancy. A three-month-old infant was admitted to the hospital for hepatomegaly. Abdominal ultrasonography, a CT-scan, and MRI studies demonstrated bilateral diffuse hepatic nodules, which were characteristic of hepatic hemangioendothelioma. A highly elevated alpha-fetoprotein (AFP) level misled us to an impression of hepatoblastoma, but the pathology report through an open biopsy disclosed a liver hemangioendothelioma. The patient responded to methylprednisolone therapy. A follow-up sonogram revealed regression of the hepatic masses. This case emphasizes that an elevated AFP level of up to 400 ng/ml is normally found in some neonates until two months of age. Careful interpretation of this value is very important, especially when it is associated with a hepatic tumor. Herein, we present a case of infantile hemangioendothelioma in a three-month-old boy with a highly elevated serum AFP.

Purification and characterization of the nuclear ribonuclease P of Aspergillus nidulans

In Aspergillus nidulans, the nuclear ribonuclease P was separated from its mitochondrial counterpart by Q-Sepharose chromatography, and a precursor-tRNA(His) processing assay system was used to discriminate nuclear ribonuclease P activity from the mitochondrial counterpart. The nuclear ribonuclease P was purified to near homogeneity from whole-cell extracts. A 2150-fold purification with a yield of 2.3% was achieved by five types of chromatography including tRNA affinity chromatography and glycerol gradient velocity sedimentation. This enzyme, which had a molecular mass of 580 kDa determined by both glycerol-gradient sedimentation analysis and gel-permeation chromatography, appeared to be composed of seven polypeptides and an RNA molecule. Seven polypeptides, with masses of 125, 85, 45, 33, 30, 21, 19 kDa, were consistently copurified with nuclear ribonuclease P activity through MonoS and tRNA affinity chromatography and in a glycerol gradient. As judged by a micrococcal-nuclease-sensitivity assay, nuclear ribonuclease P required an RNA component for its activity, as do other ribonuclease Ps. Analysis of the radiolabeled 5' end of RNAs copurified with nuclear ribonuclease P implied that RNA molecules in the purified nuclear ribonuclease P originated from a common RNA molecule, the putative RNA molecule of nuclear ribonuclease P. Comparison of the two ribonuclease Ps in A. nidulans showed that the protein and RNA components of the nuclear ribonuclease P were different from those of the mitochondrial counterpart.

Molecular cloning and characterization of a Drosophila p38 mitogen-activated protein kinase

A mitogen-activated protein kinase (MAPK) has been cloned and sequenced from a Drosophila neoplasmic l(2)mbn cell line. The cDNA sequence analysis showed that this Drosophila kinase is a homologue of mammalian p38 MAPK and the yeast HOG1 gene and thus was referred to as Dp38. A distinguishing feature of all MAPKs is the conserved sequence TGY in the activation domain. Dp38 was rapidly tyrosine 186-phosphorylated in response to osmotic stress, heat shock, serum starvation, and H2O2 in Drosophila l(2)mbn and Schneider cell lines. However, unlike mammalian p38 MAPK, the addition of lipopolysaccharide (LPS) did not significantly affect the phosphorylation of Dp38 in the LPS-responsive l(2)mbn cell line. Following osmotic stress, tyrosine 186-phosphorylated forms of Dp38 MAPK were detected exclusively in nuclear regions of Schneider cells. Yeast complementation studies demonstrated that the Saccharomyces cerevisiae HOG1 mutant strain JBY10 (hog1-Delta1) was functionally complemented by Dp38 cDNA in hyperosmolar medium. These findings demonstrate that similar osmotic stress-responsive signal transduction pathways are conserved in yeast, Drosophila, and mammalian cells, whereas LPS signal transduction pathways appear to be different.

Acquired choledochal cyst from anomalous pancreatobiliary duct union

The high incidence of anomalous pancreatobiliary duct union (APBDU) in children who have a choledochal cyst has been well documented. Additionally, cylindrical dilatation of the bile duct has been reproduced in animal models by anastomosing the pancreatic duct to the bile duct. In recent years, APBDU has been considered a possible etiologic factor in the formation of a choledochal cyst. The authors observed a progressive cylindrical dilatation of the common bile duct in a 6-year-old boy over an 18-month period. An operative cholangiogram showed a type Ic choledochal cyst and a type B APBDU (Todani classification). This clinical experience suggests that a normal common bile duct in children can be progressively dilated and become an acquired choledochal cyst arising as a complication of the preexisting APBDU.

Involvement of nuclear factor-kappa B in platelet-activating factor-mediated tumor necrosis factor-alpha expression

Tumor necrosis factor (TNF)-alpha and platelet-activating factor (PAF) are important mediators of inflammatory reactions, and their release is controlled by a positive feedback network. However, the regulatory mechanisms underlying the interaction of these two molecules are unknown. Within 10 min of the injection of lipopolysaccharide (LPS) into C57BL/6 mice, effects inducible by PAF such as anaphylactic shock-like symptoms, disseminated intravascular coagulation, and hemorrhage in renal medullae were observed, and all these pathological changes were prevented by the PAF antagonist, BN 50739. The plasma level of PAF after LPS injection reached a peak at 5 min. TNF-alpha gene expression was evident 20 min after LPS injection and was maximal at 40 min, and the level of serum TNF-alpha reached a peak at 1 h. Pretreatment with BN 50739 inhibited LPS-induced TNF-alpha gene expression and protein synthesis in a dose-dependent manner. Injection of PAF or treatment of the macrophage cell line, J774A.1, with PAF activated the transcription factor, nuclear factor (NF)-kappa B, which is essential for inducible TNF-alpha transcription. The activation of NF-kappa B by PAF preceded the LPS-mediated TNF-alpha gene expression. Pretreatment with BN 50739 inhibited LPS-induced mobilization of NF-kappa B in a dose-dependent manner in vivo as well as in vitro. These data suggest that PAF, which is released immediately or shortly after LPS injection, induces the expression of TNF-alpha through the activation of NF-kappa B.

Platelet-derived growth factor (PDGF)-signaling mediates radiation-induced apoptosis in human prostate cancer cells with loss of p53 function

Platelet-derived growth factor (PDGF) signals a diversity of cellular responses in vitro, including cell proliferation, survival, transformation, and chemotaxis. PDGF functions as a "competence factor" to induce a set of early response genes expressed in G1 including p21WAF1/CIP1, a functional mediator of the tumor suppressor gene p53 in G1/S checkpoint. For PDGF-stimulated cells to progress beyond G1 and transit the cell cycle completely, progression factors in serum such as insulin and IGF-1 are required. We have recently shown a novel role of PDGF in inducing apoptosis in growth-arrested murine fibroblasts. The PDGF-induced apoptosis is rescued by insulin, suggesting that G1/S checkpoint is a critical determinant for PDGF-induced apoptosis. Because recent studies suggest that radiation-induced signal transduction pathways interact with growth factor-mediated signaling pathways, we have investigated whether activation of the PDGF-signaling facilitates the radiation-induced apoptosis in the absence of functional p53. For this study we have used the 125-IL cell line, a mutant p53-containing, highly metastatic, and hormone-unresponsive human prostate carcinoma cell line. PDGF signaling is constitutively activated by transfection with a p28v-sis expression vector, which was previously shown to activate PDGF alpha- and beta- receptors. Although the basal level of p21WAF1/CIP1 expression and radiation-induced apoptosis were not detectable in control 125-IL cells as would be predicted in mutant p53-containing cells, activation of PDGF-signaling induced expression of p21WAF1/CIP1 and radiation-induced apoptosis. Our study suggests that the level of "competence" growth factors including PDGF may be one of the critical determinants for radiation-induced apoptosis, especially in cells with loss of p53 function at the site of radiotherapy in vivo.

Cardiac angiomyolipoma: radiologic and pathologic correlation

Primary tumors of the heart are rare. We report a case of large cardiac angiomyolipoma (hamartoma) that presented as a fat-containing tumor mass on imaging studies, diagnosed radiographically as teratoma. The patient was admitted through the emergency room at Tainan Municipal Hospital because of severe dyspnea. A chest radiograph revealed marked widening of the mediastinum. Echocardiography and computed tomographic scanning of the thorax showed a mass of mixed density with calcification. A teratoma with intrapericardial invasion was suspected. Sternotomy disclosed a large intrapericardial lobulated mass (34 x 30 x 12 cm, 3,150 g) arising from the right atrium, with severe adhesion to the origin of the inferior vena cava. Histopathologic examination demonstrated an angiomyolipoma of the heart. To our knowledge, this is the largest cardiac angiomyolipoma reported. We report this case to emphasize that a differential diagnosis of angiomyolipoma must be included in a patient with a fat-containing cardiac tumor.

Percutaneous transhepatic transluminal forceps biopsy in obstructive jaundice

BACKGROUND/AIMS

To evaluate the technical feasibility and sensitivity of percutaneous transluminal forceps biopsy of bile duct diseases.

MATERIAL AND METHODS

Seventeen fluoroscopic-guided transluminal forceps biopsies were performed in 16 patients with obstructive jaundice. The technique was performed through an existing percutaneous transhepatic tract. Multiple specimens were obtained after passing the forceps biopsy into a long 9-French sheath and the specimens were fixed with formalin for histopathologic diagnosis.

RESULTS

Adequate samples for histological diagnosis was obtained in 12 of 17 procedures (sensitivity, 71%). Pathologic reports included pancreatic head carcinoma n = 2, cholangiocarcinoma n = 3, hepatoma with intrahepatic-bile duct invasion n = 3, common bile duct tumors n = 3 and chronic inflammation n = 1. Minor complications such as pain was noted in three patients while transient hemobilia was seen in two patients.

CONCLUSIONS

Percutaneous transhepatic transluminal forceps biopsy is a safe technique which is easy to perform. This can be done through an existing transhepatic biliary tract with a sensitivity rate of 71%.

Purification and characterization of the precursor tRNA 3'-end processing nuclease from Aspergillus nidulans

The precursor-tRNA 3'-end processing nuclease activity was purified homogeneously about 15,300 fold from the heat-treated fraction. The precursor-tRNA 3'-end processing nuclease was a single polypeptide of 160,000 Da. This nuclease generates a mature 3'-end of nuclear tRNA(Asp) of Aspergillus nidulans by the endonuclease activity and prefers the 5'-end processed tRNA(Asp) rather than primary precursor-tRNA(Asp) as a substrate. However, this enzyme did not process both primary mitochondrial precursor-tRNA(His) and 5'-end processed mitochondrial precursor-tRNA(His) of A. nidulans.

A protective role of platelet-activating factor in murine candidiasis

Platelet-activating factor (PAF) is a potent phospholipid-derived modulator of immunological and inflammatory processes. In this study, the role of exogenous and endogenous PAF in resistance to infection with Candida albicans was investigated. Administration of PAF following a lethal challenge of C. albicans significantly protected mice from death and reduced the number of organisms in the kidneys. Neutralization of endogenous PAF with the PAF antagonist BN50739 shortened the mean survival time and increased the number of C. albicans cells per kidney. Shortly after infection of mice (30 min), significant levels of PAF were detected in the serum. PAF-induced protection appears to be mediated through the actions of tumor necrosis factor alpha (TNF-alpha), since pretreatment with anti-TNF-alpha before each injection of PAF abrogated the majority of PAF-induced enhanced resistance. Administration of PAF in vivo elevated serum TNF-alpha levels and TNF-alpha mRNA expression in the kidney. Production of TNF-alpha was markedly diminished by pretreatment with the PAF antagonist BN50739 prior to infection with C. albicans. We conclude that PAF, which is produced during infection with C. albicans, plays an important role in determining the level of resistance to this infectious microorganism. This effect of PAF appears to be mediated, at least in part, through the induction of TNF-alpha.

Laparoscopic finding and imaging of the iatrogenic duodenal intramural hematoma

Intramural duodenal hematoma is rarely seen in adults and may occur as an iatrogenic complication of endoscopic injection for peptic ulcer treatment. In the appropriate clinical setting, the diagnosis is easy with its ultrasonography and computed tomography characteristic findings. In one of our patients, UGI study revealed duodenal obstruction, bowel related lesion in sonography and hyperdense mass lesion in computed tomography. Clinical presentation of severe vomiting and epigastralgia were noted. Laparoscopy confirmed the location of the hematoma and subsequent evacuation was performed. The symptoms were relieved after the operation and a follow-up sonography demonstrated the regression of the duodenal hematoma.

Actual half-life of alpha-fetoprotein as a prognostic tool in pediatric malignant tumors

In a retrospective study, the prognostic value of monitoring the decay of alpha-fetoprotein (AFP) was assessed. Serum AFP was determined serially in 18 children with malignant germ-cell or hepatic tumors: 7 endodermal sinus tumor, 3 embryonal carcinoma, 5 malignant teratoma, 2 hepatoblastomas, and 1 hepatocellular carcinoma. The actual half-life (AHL) of AFP was computed after surgical resection of the tumor. In group 1, which had complete resection and no recurrence during follow-up (n = 13), the AHL of AFP was 4.0 +/- 0.9 days. In group 2, which had incomplete resection or recurrence during follow-up (n = 5), the AHL of AFP was 24.8 +/- 20 days, significantly longer than that of group 1 (P = 0.0026). The increased AHL of AFP indicated residual active tumor after surgical resection. The AHL of AFP may be more sensitive than serial monitoring of AFP in detecting preclinical recurrence after surgical resection of AFP-secreting tumors. Treatment strategies can be based on AFP clearance, and prospective clinical trials are warranted.

An unusual case of monozygotic epigastric heteropagus twinning

Epigastric heteropagus refers to unequal and asymmetric conjoined twins in which the dependent component (parasite) is smaller and usually attached to the epigastrium of the dominant component (autosite). Epigastric heteropagus is a very rare type of conjoined twins. It is generally assumed that conjoined twins represent a form of monozygotic twinning, but there has been no confirmation of this monozygotic hypothesis. Epigastric heteropagus twins differ in several ways from symmetrical conjoined twins. These include male preponderance, and no major connection of vessels, bowels, or bones. These significant characteristics suggest to the authors that the fusion of two fertilized ova and the atrophy of one fetus resulted in this interesting malformation. However, a DNA study indicated monozygotic origin in their case. The possible pathogenesis was ischemic atrophy of the body structure of the monozygotic conjoined twins at an early gestational age.

Gamma/delta T lymphocytes in the BCG granulomatous lesions

Recent studies in man and animal models have demonstrated that TCR-gamma delta-bearing T cells (gamma delta T cells) are activated by mycobacteria and accumulate in the sites of mycobacterial infection. Although the function of gamma delta T cells remains unclear, some data suggest a potential role for these cells in the granulomatous immune response. To address the presence of gamma delta T cells within the BCG granulomas, we have characterized the TCR phenotype of T-lymphocytes present in the BCG granulomatous lesion immunohistochemically using a monoclonal antibody to TCR delta 1 and others. Fairly large numbers of gamma delta T cells were located at the periphery of the BCG granulomas without necrosis and most of them also expressed CD8. However, gamma delta T cells were rarely present in the granulomas with central caseous necrosis, calcification and fibrotic changes. With these results, it might be speculated that the CD8+ gamma delta T lymphocytes participate in the BCG granuloma formation mainly in the early stage.

Fourier transform ion cyclotron resonance detection of multiphoton ionization spectroscopy

Fourier transform ion cyclotron resonance (FT-ICR) detection was tested for resonanceenhanced multiphoton ionization (REMPI) spectroscopy. The (2+1) REMPI spectra of acetaldehyde were obtained in the wavelength range 364-354 nm via a two-photon resonant 3s ← n Rydberg transition. The space-charge effects on the REMPI spectra were examined in the vicinity of the 0 0 (0) transition. The trapping efficiency measurement shows that all the ions produced from REMPI dissociation processes are arrested in the ion cyclotron resonance cell even in the presence of space-charge interactions. Axial kinetic energy release distributions of ions were extracted from the trapping efficiency data obtained under a new space-charge-free condition. FT-ICR peak heights were measured as a function of pressure at different laser powers, magnetic field strengths, and ion excitation methods to test for the detection linearity. The FT-ICR detection responds linearly to the number of ions in a low pressure limit. The product branching ratio was measured by using various ion excitation methods and was compared with the previous quadrupole mass spectrometric study. FT-ICR detection yields the mass-selected REMPI spectra and the product branching ratio in the absence of kinetic shifts.

Clinical experience with conservative surgery for vaginal endodermal sinus tumor

Two cases of vaginal endodermal sinus tumor (EST), a rare pediatric malignancy, were managed with conservative surgery followed by adjuvant chemotherapy. The first case involved a 9-month-old girl with EST of the vagina, who was treated with a partial vaginectomy and VAC regimen (vincristine, actinomycin D, cyclophosphamide) during a 2-year period. The serum alpha-fetoprotein (AFP) level returned to normal after excision of the tumor, and it remained normal throughout the treatment period. There was no evidence of disease 30 months after diagnosis. The second case involved an 8-month-old girl with EST of the vagina, who was treated with local excision of the mass through a vaginotomy. The VAC regimen was administered, but the serum AFP level remained elevated. A follow-up abdominopelvic computed tomography scan, taken 4 months after the operation, showed local recurrence of the tumor. The VAC regimen was then changed to a BEP regimen (bleomycin, etoposide, cisplatin). The serum AFP level returned to normal after 2 courses of the new regimen, and no tumor was visible on the follow-up magnetic resonance imaging study. For vaginal EST, primary conservative surgery and adjuvant chemotherapy are attractive measures to preserve both reproductive and sexual function. The extent of conservative surgery requires at least a partial vaginectomy. Simple tumor excision may not be adequate to achieve cure or to prevent local recurrence, even with adjuvant chemotherapy. The serum AFP level is useful for diagnosing and monitoring vaginal EST in the infant.

Conformation and activity of +H2-Pro-Leu-Gly-NH2 and its analogues modified at the leucyl residue

In order to investigate the relation between the conformation and the ability to modulate dopamine receptors, conformational free-energy calculations using an empirical potential (ECEPP/3) and hydration shell model were carried out on the tripeptide +H2-Pro-Leu-Gly-NH2 (PLG) and its analogues in which the Leu residue is replaced with Phe, Ahx (L-2-aminohexanoic acid), Ile, Abu and Ala residues in the unhydrated and hydrated states. PLG and two tripeptides possessing Phe and Ahx residues show dopamine receptor modulating activity, while the other tripeptides do not. Irrespective of activities, PLG and its analogues are found to have the high probabilities to form beta-bends of types II and I in the unhydrated state. However, in the hydrated state, the beta-bend probabilities of the PLG analogues decrease significantly compared with those in the unhydrated state. These results indicate that the beta-bend structure is a necessary factor for the PLG analogues to be active, but not a sufficient factor, and that the interactions of water molecules with the backbone may force the tripeptides to be more distorted or extended. The size and the orientation of the hydrophobic moiety of the second residue seem to be of consequence in eliciting the activity of the tripeptides.

Characterization of a bifunctional cellulase and its structural gene. The cell gene of Bacillus sp. D04 has exo- and endoglucanase activity

Bacillus sp. D04 secreted a bifunctional cellulase that had a molecular weight of 35,000. This cellulase degraded Cm-cellulose, cellotetraose, cellopentaose, p-nitrophenyl-beta-D-cellobioside, and avicel PH101. Based on the high performance liquid chromatography analysis of the degradation products, this cellulase randomly cleaved internal beta-1, 4-glycosidic bonds in cellotetraose and cellopentaose as an endoglucanase. It also hydrolyzed the aglycosidic bond in p-nitrophenyl-beta-D-cellobioside and cleaved avicel to cellobiose as an exoglucanase. Cellobiose competitively inhibited the p-nitrophenyl-beta-D-cellobioside degrading activity but not Cm-cellulose degrading activity. Ten mM p-chloromercuribenzoate inhibited p-nitrophenyl-beta-D-cellobioside degrading activity completely, but Cm-cellulose degrading activity incompletely. Cm-cellulose increased p-nitrophenyl-beta-D-cellobioside degrading activity, and vice versa, whereas methylumbelliferyl-beta-D-cellobiose strongly inhibited p-nitrophenyl-beta-D-cellobioside degrading activity. The cellulase gene (cel gene), 1461 base pairs, of Bacillus sp. D04 was cloned. The nucleotide sequence of the cel gene was highly homologous to those of Bacillus subtilis DLG and B. subtilis BSE616. The cel gene was overexpressed in Escherichia coli, and its product was purified. The substrate specificity and substrate competition pattern of the purified recombinant cellulase were the same as those of the purified cellulase from Bacillus sp. D04. These results suggest that a single polypeptide cellulase had both endo- and exoglucanase activities and each activity exists in a separate site.

Long-term follow-up of gracilis muscle transposition in children

Sixteen children of uncontrollable fecal incontinence have been treated with Pickrell's gracilis muscle transposition since 1983: 12 had an imperforate anuses with multiple corrective operative procedures and 4 had traumatic destructions of anal sphincters. We report a series of 11 cases whom we followed-up over a period of 0.8 to 10.5 years (mean; 5.6 years). Seven patients were evaluated by anorectal manometry. All patients except one who had left hemipelvectomy and permanent colostomy showed nearly normal continence during the follow-up period. There was no evidence of fibrosis in the transposed muscles and the tensions of the transposed muscles were well maintained. The voluntary contractions of the transposed muscles were well maintained and efficient in all cases. The general manometric parameters did not correlate well with the functional results; however, there was a strong correlation in the S/R ratio (maximum squeeze pressure/resting pressure) with the functional results. We believe that the good functional outcome of this procedure need not only the meticulous surgical technique but also the personal motivation and the compliance with physiotherapy. In conclusion, although the gracilis muscle transposition never results in normal continence, acceptable continence can be achieved in the selected patients.

Ultrasonographic evaluation of multicystic dysplastic kidney

Eleven cases of multicystic dysplastic kidney (MCDK) in children were diagnosed over an 11 year period. All underwent postnatal ultrasound (US) studies. Four different patterns of MCDK were recognized: (1) Six cases presented with the classic sonogram of multicystic components. (2) Three cases had hydronephrotic form; correct diagnosis between hydronephrotic form of MCDK and hydronephrosis was difficult as there was a medially-located, large, lobulated cyst and there was connection between the large cyst and neighboring small cysts. (3) One case initially presented with normal renal sonogram but a small cyst appeared on follow up sonogram and there was also decreased renal size and increased echogenecity. (4) One case had only two moderate-sized cysts but no identifiable renal parenchyma. Two cases had follow-up US examination and one dysplastic kidney decreased in renal size on follow-up sonogram. Intravenous urography and radionuclide study revealed both these dysplastic kidneys to be nonfunctioning. Nine children had surgical resection of the diseased kidneys. Contralateral renal anomalies were detected in five children, which included ureteropelvic junction stenosis, ureterovesical junction stenosis, distal ureteral stenosis and polycystic kidney disease. Two of three hydronephrotic forms of MCDK had contralateral ureteral stenosis. Two of six classic forms of MCDK had contralateral ureteral stenosis. The proportion of contralateral ureteral stenosis was higher in the group of hydronephrotic forms of MCDK. Ultrasonography is beneficial for conclusive diagnosis of MCDK; however, a differential diagnosis of simple hydronephrosis needs to be considered.