Cloning and functional characterization of mouse IkappaBepsilon

The biological activity of the transcription factor NF-kappaB is mainly controlled by the IkappaB proteins IkappaBalpha and IkappaBbeta, which restrict NF-kappaB in the cytoplasm and enter the nucleus where they terminate NF-kappaB-dependent transcription. In this paper we describe the cloning and functional characterization of mouse IkappaBepsilon. Mouse IkappaBepsilon contains 6 ankyrin repeats required for its interaction with the Rel proteins and is expressed in different cell types where we found that it is up-regulated by NF-kappaB inducers, as is the case for IkappaBalpha and human IkappaBepsilon. IkappaBepsilon functions as a bona fide IkappaB protein by restricting Rel proteins in the cytoplasm and inhibiting their in vitro DNA binding activity. Surprisingly, IkappaBepsilon did not inhibit transcription of genes regulated by the p50/p65 heterodimer efficiently, such as the human interferon-beta gene. However, IkappaBepsilon was a strong inhibitor of interleukin-8 expression, a gene known to be regulated by p65 homodimers. In addition, IkappaBepsilon appears to function predominantly in the cytoplasm to sequester p65 homodimers, in contrast with the other two members of the family, IkappaBalpha and IkappaBbeta, which also function in the nucleus to terminate NF-kappaB-dependent transcriptional activation.

Chemical carboxy-terminal sequence analysis of peptides using acetyl isothiocyanate

A new derivatizing reagent, acetyl isothiocyanate (AITC), is applied for C-terminal peptide sequencing. It has been successfully used to sequence six C-terminal residues of a synthetic peptide at low nanomole levels. According to the mechanism study of the derivatization of C-terminal amino acid with various reagents, the derivatizing reagents (R-N=C=S or SCN-) were classified into three types: type I, the ionic compound (e.g., HSCN, NH4SCN, KSCN); type II, R is a good leaving group (e.g., TMS-ITC, TBSn-ITC); type III, R is reactive (e.g., AITC, BITC, DPP-ITC). Type III reagents are superior to other reagents because their double-function of activation and derivatization. Unlike type I and type II reagents, type III reagent chemistry does not require oxazolinone formation which can cause racemization. Compared with benzoyl isothiocyanate, diphenyl phosphoroisothiocyanatidate, trimethylsilyl isothiocyanate, and ammonium thiocyanate, AITC is the most effective derivatizing reagent. As a type III reagent, AITC possesses some features such as no need for oxazolinone formation, no requirement for separate activation step, high reactivity, easy preparation, and low absorption at 260-270 nm. Different reaction conditions were investigated for optimization and the chemical mechanism of AITC chemistry is illustrated. A convenient and efficient approach for synthesis of amino acid thiohydantoins as reference standards has also been developed.

Proton nuclear magnetic resonance studies on huwentoxin-I from the venom of the spider Selenocosmia huwena: 2. Three-dimensional structure in solution

The three-dimensional structure in aqueous solution of native huwentoxin-I, a neurotoxin from the venom of the spider Selenocosmia huwena, has been determined from two-dimensional H NMR data recorded at 500 and 600 MHz. Structural constraints consisting of interproton distances inferred from NOEs and dihedral angles from spin-spin coupling constants were used as input for distance geometry calculation with the program XPLOR 3.1. The best 10 structures have NOE violations < 0.3 A, dihedral violations < 2 degrees, and pairwise root-mean-square differences of 1.08 (+/- 0.20) A over backbone atoms (N, C alpha, C). The molecule adopts a compact structure consisting of a small triple-stranded antiparallel beta-sheet and five beta-turns. A small hydrophobic patch consisting of Phe 6, Trp 28, and Trp 31 is located on one side of the molecule. All six lysine residues are distributed on the molecular surface. The three disulfide bridges are buried within the molecule. The structure contains an "inhibitor cystine knot motif" which is adopted by several other small proteins, such as omega-conotoxin, agatoxin IVA, and gurmarin.

[Comparison of stature growth curves in children and adolescents]

Growth charts of height in Chinese children and adolescents (excluding Taiwan and Hong Kong) in the 1980s and 1990s were fitted to JPA2 model to study their growth and developmental characteristics and their future trend and to compare them with the criteria for growth in the developed countries and areas. Results showed that fitted growth curves were comparable. The difference in body height of children in cities during puberty period was the most significant during the 1980s. Body height of boys and girls aged over seven to maturity period in Beijing during the 1990s was higher than that in Hong Kong and Japan, and reached basically the criteria set by the National Center for Health Statistics (NCHS), United States, but body height of adults was still three to four centimeters lower than that in criteria set by NCHS. Body height in adolescents in Beijing was kept in stable as compared with that in the 1980s.

Intra- and intermolecular cooperative binding of high-mobility-group protein I(Y) to the beta-interferon promoter

The mammalian high-mobility-group protein I(Y) [HMG I(Y)], while not a typical transcriptional activator, is required for the expression of many eukaryotic genes. HMG I(Y) appears to recruit and stabilize complexes of transcriptional activators through protein-DNA and protein-protein interactions. The protein binds to the minor groove of DNA via three short basic repeats, preferring tracts of adenines and thymines arranged on the same face of the DNA helix. However, the mode by which these three basic repeats function together to recognize HMG I(Y) binding sites has remained unclear. Here, using deletion mutants of HMG I(Y), DNase I footprinting, methylation interference, and in vivo transcriptional assays, we have characterized the binding of HMG I(Y) to the model beta-interferon enhancer. We show that two molecules of HMG I(Y) bind to the enhancer in a highly cooperative fashion, each molecule using a distinct pair of basic repeats to recognize the tandem AT-rich regions of the binding sites. We have also characterized the function of each basic repeat, showing that only the central repeat accounts for specific DNA binding and that the presence of a second repeat bound to an adjacent AT-rich region results in intramolecular cooperativity in binding. Surprisingly, the carboxyl-terminal acidic tail of HMG I(Y) is also important for specific binding in the context of the full-length protein. Our results present a detailed examination of HMG I(Y) binding in an important biological context, which can be extended not only to HMG I(Y) binding in other systems but also to the binding mode of many other proteins containing homologous basic repeats, which have been conserved from bacteria to humans.

A method for preparation of amino acid thiohydantoins from free amino acids activated by acetyl chloride for development of protein C-terminal sequencing

A novel and efficient method to prepare amino acid thiohydantoins, which are required as reference standards for development of C-terminal protein sequencing, is reported. Amino acid thiohydantoins were prepared using a straightforward method involving reaction of 20 free amino acids with acetyl chloride as activating reagent and trimethylsilyl isothiocyanate (TMS-ITC) as derivatizing reagent. The products were characterized by HPLC, uv spectra, amino acid analysis, MS, and NMR. Different reaction conditions were investigated and the chemical mechanism of the formation of amino acid thiohydantoins was illustrated.

Regulation of tRNA suppressor activity by an intron-encoded polyadenylation signal

A 26-nt sequence from the 3' UTR of the yeast GAL7 mRNA directs accurate and efficient cleavage and polyadenylation to form the 3' end of the GAL7 mRNA in vivo and in vitro. Here we asked whether this polyadenylation signal can function within the context of a tRNA. Insertion of the GAL7 signal into the intron of the dominant SUP4 nonsense suppressor allowed us to judge the effect of the insert on SUP4 function by observation of nonsense suppression efficiency in vivo. The GAL7 signal impairs the function of SUP4 in an orientation-dependent manner in vivo, consistent with its ability to specify cleavage and polyadenylation in this context in vitro. Mutation of a UA repeat within the GAL7 signal restores SUP4 function partially, consistent with the role of this repeat as an efficiency element in polyadenylation. Mutations that impair the mRNA 3' end-processing factors Rna14p and Rna15p restore suppressor function partially. Northern blot analysis, PCR amplification, and DNA sequence analysis show that the GAL7 signal directs polyadenylation within the body of pre-SUP4 and within the terminator, suggesting that polyadenylation inhibits 5' and 3' end processing, as well as removal of the pre-tRNA intron. These findings indicate that the GAL7 polyadenylation signal is capable of targeting a pre-tRNA to the mRNA processing pathway.

Neurotrophic immunophilin ligands stimulate structural and functional recovery in neurodegenerative animal models

Although immunosuppressant immunophilin ligands promote neurite outgrowth in vitro, their neurotrophic activities are clearly independent of their immunosuppressive activity. In the present report, a novel nonimmunosuppressive immunophilin ligand, GPI-1046 (3-(3-pyridyl)-1-propyl (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarboxylate+ ++) is described. In vitro, GPI-1046 bound to FK506 binding protein-12 and elicited neurite outgrowth from sensory neuronal cultures with picomolar potency with maximal effects comparable to nerve growth factor. In vivo, GPI-1046 stimulated the regeneration of lesioned sciatic nerve axons and myelin levels. In the central nervous system, GPI-1046 promoted protection and/or sprouting of serotonin-containing nerve fibers in somatosensory cortex following parachloroamphetamine treatment. GPI-1046 also induced regenerative sprouting from spared nigrostriatal dopaminergic neurons following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in mice or 6-hydroxydopamine (6-OHDA) toxicity in rats. The rotational abnormality in 6-OHDA treated rats was alleviated by GPI-1046. These neurotrophic actions in multiple models suggest therapeutic utility for GPI-1046 in neurodegenerative diseases.

[Determination of alkylmercuric compounds in human body fluids by gas chromatography--atomic absorption spectrophotometry]

In order to detect trace of alkylmercuric compounds in human body fluids, a highly sensitive, selective and rapid method, based on the coupling of gas chromatography with atomic absorption spectrophotometry, has been developed. The transfer-tube was made up of Teflon, with stainless steel tubes in the two sides. The atomization of alkylmercuric compounds was performed in quartz tube. The quantitative determination of alkylmercuric compounds in urine and blood samples collected from the workers exposing to metallic mercury, has been extensively carried out in this work. The optimal Westoo program was used to enrich methylmercuric chloride in samples, Extracts of methylmercuric chloride in benzene were determined by GC-AAS, with a total recovery of more than 90%. Dimethylmercury in samples was extracted once by xylene. Then the extracts were determined, with a total recovery of 65%-70%. The detectable limit for mercury was 0.01ng. The methylation of mercury was confirmed in our experiment. This method can be used for the determination of other metallic compounds.

Segmentation of handwritten interference marks using multiple directional stroke planes and reformalized morphological approach

A new algorithm for the extraction of words from printed documents that have interference marks and other strokes, cutting across text, is presented. Morphological operations based on multiple direction projection planes and skeleton images are adopted here to prevent the "flooding water" effect of conventional morphological operations. Test results indicate the feasibility of the proposed approach.

Effect of Ca2+ on in vitro astrocyte injury

Current literature suggests that a massive influx of Ca2+ into the cells of the CNS induces cell damage associated with traumatic brain injury (TBI). Using an in vitro model for stretch-induced cell injury developed by our laboratory, we have investigated the role of extracellular Ca2+ in astrocyte injury. The degree of injury was assessed by measurement of propidium iodide uptake and release of lactate dehydrogenase. Based on results of in vivo models of TBI developed by others, our initial hypothesis was that decreasing extracellular Ca2+ would result in a reduction in astrocyte injury. Quite unexpectedly, our results indicate that decreasing extracellular Ca2+ to levels observed after in vivo TBI increased astrocyte injury. Elevating the extracellular Ca2+ content to twofold above physiological levels (2 mM) produced a reduction in cell injury. The reduction in injury afforded by Ca2+ could not be mimicked with Ba2+, Mn2+, Zn2+, or Mg2+, suggesting that a Ca(2+)-specific mechanism is involved. Using 45Ca2+, we demonstrate that injury induces a rapid influx of extracellular Ca2+ into the astrocyte, achieving an elevation in total cell-associated Ca2+ content two- to threefold above basal levels. Pharmacological elevation of intracellular Ca2+ levels with the Ca2+ ionophore A23187 or thapsigargin before injury dramatically reduced astrocyte injury. Our data suggest that, contrary to popular assumptions, an elevation of total cell-associated Ca2+ reduces astrocyte injury produced by a traumatic insult.

Heat shock disassembles the nucleolus and inhibits nuclear protein import and poly(A)+ RNA export

Heat shock causes major positive and negative changes in gene expression, drastically alters the appearance of the nucleolus and inhibits rRNA synthesis. We here show that it causes many yeast nucleolar proteins, including the fibrillarin homolog Nop1p, to relocate to the cytoplasm. Relocation depends on several proteins implicated in mRNA transport (Mtrps) and is reversible. Two observations indicate, surprisingly, that disassembly results from a reduction in Ssa protein (Hsp70) levels: (i) selective depletion of Ssa1p leads to disassembly of the nucleolus; (ii) preincubation at 37 degrees C protects the nucleolus against disassembly by heat shock, unless expression of Ssa proteins is specifically inhibited. We observed that heat shock or reduction of Ssa1p levels inhibits protein import into the nucleus and therefore we propose that inhibition of import leads to disassembly of the nucleolus. These observations provide a simple explanation of the effects of heat shock on the anatomy of the nucleolus and rRNA transcription. They also extend understanding of the path of nuclear export. Since a number of nucleoplasmic proteins also relocate upon heat shock, these observations can provide a general mechanism for regulation of gene expression. Relocation of the hnRNP-like protein Mtr13p (= Npl3p, Nop3p), explains the heat shock sensitivity of export of average poly(A)+ RNA. Strikingly, Hsp mRNA export appears not to be affected.

Immunohistochemical study of epithelioid hemangioendothelioma in the leg: a case report

Epithelioid hemangioendothelioma is a relatively rare lesion. Although its histogenesis has been well described, its immunohistochemical characteristics remain controversial. A case of epithelioid hemangioendothelioma of the soft tissue of the right leg in a 67-year-old Chinese woman is reported. Histologic findings of intracytoplasmic lumina in the tumor cells and positive immunostaining for vimentin, factor VIII-related antigen. CD34 and Ulex europaeus agglutinin 1 (UEA-1) were obtained, demonstrating differentiation of the tumor cells to endothelial cells, although staining for antibodies to cytokeratins AE1/AE3 and CAM5.2 was weak. CD34 as well as Factor VIII-related antigen is a useful marker of endothelial differentiation in this tumor. A review of the literature is also presented.

A DEAD-box-family protein is required for nucleocytoplasmic transport of yeast mRNA

An enormous variety of primary and secondary mRNA structures are compatible with export from the nucleus to the cytoplasm. Therefore, there seems to be a mechanism for RNA export which is independent of sequence recognition. There nevertheless is likely to be some relatively uniform mechanism which allows transcripts to be packaged as ribonucleoprotein particles, to gain access to the periphery of the nucleus and ultimately to translocate across nuclear pores. To study these events, we and others have generated temperature-sensitive recessive mRNA transport (mtr) mutants of Saccharomyces cerevisiae which accumulate poly(A)+ RNA in the nucleus at 37 degrees C. Several of the corresponding genes have been cloned. Upon depletion of one of these proteins, Mtr4p, conspicuous amounts of nuclear poly(A)+ RNA accumulate in association with the nucleolus. Corresponding dense material is also seen by electron microscopy. MTR4 is essential for growth and encodes a novel nuclear protein with a size of approximately 120 kDa. Mtr4p shares characteristic motifs with DEAD-box RNA helicases and associates with RNA. It therefore may well affect RNA conformation. It shows extensive homology to a human predicted gene product and the yeast antiviral protein Ski2p. Critical residues of Mtr4p, including the mtr4-1 point mutation, have been identified. Mtr4p may serve as a chaperone which translocates or normalizes the structure of mRNAs in preparation for export.

Stretch-induced injury of cultured neuronal, glial, and endothelial cells. Effect of polyethylene glycol-conjugated superoxide dismutase

BACKGROUND AND PURPOSE

There is abundant evidence that after in vivo traumatic brain injury, oxygen radicals contribute to changes in cerebrovascular structure and function; however, the cellular source of these oxygen radicals is not clear. The purpose of these experiments was to use a newly developed in vitro tissue culture model to elucidate the effect of strain, or stretch, on neuronal, glial, and endothelial cells and to determine the effect of the free radical scavenger polyethylene glycol-conjugated superoxide dismutase (PEG-SOD; pegorgotein, Dismutec) on the response of each cell type to trauma.

METHODS

Rat brain astrocytes, neuronal plus glial cells, and aortic endothelial cells were grown in cell culture wells with 2-mm-thick silastic membrane bottoms. A controllable, 50-millisecond pressure pulse was used to transiently deform the silastic membrane and thus stretch the cells. Injury was assessed by quantifying the number of cells that took up the normally cell-impermeable dye propidium iodide. Some cultures were pretreated with 100 to 300 U/mL PEG-SOD.

RESULTS

Increasing degrees of deformation produced increased cell injury in astrocytes, neuronal plus glial cultures, and aortic endothelial cells. By 24 hours after injury, all cultures showed evidence of repair as demonstrated by cells regaining their capacity to exclude propidium iodide. Compared with astrocytes or neuronal plus glial cultures, endothelial cells were much more resistant to stretch-induced injury and more quickly regained their capacity to exclude propidium iodide. PEG-SOD had no effect on the neuronal or glial response to injury but reduced immediate posttraumatic endothelial cell dye uptake by 51%.

CONCLUSIONS

These studies further document the utility of the model for studying cell injury and repair and further support the vascular endothelial cell as a site of free radical generation and radical-mediated injury. On the assumption that, like aortic endothelial cells, stretch-injured cerebral endothelial cells also produce oxygen radicals, our results further suggest the endothelial cell as a site of therapeutic action of free radical scavengers after traumatic brain injury.

[Percutanous trans-catheter intervention for the diagnosis and treatment of malignant pericardial effusion, with a report of 50 cases]

Diagnosis and treatment of malignant pericardial effusion are difficult in clinical practice. This paper reports the feasibility and reliability of percutanous trans-catheter intervention for the diagnosis and treatment of malignant pericardial effusion. Under echocardiagraphic guidence, pericardial puncture was performed and a heamostasis sheath was placed in situ by Seldinger technique. Through the sheath multiple biopsies of the pericardium were taken for pathological examination. A pigtail catheter was inserted to drain off the effusion. According to pathological report suitable anti-cancer drugs were instilled into the pericardial cavity through indwelling catheter for 3-5 days. The catheter was withdrawn when fluid did not re-accumulate. Diagnosis was made in over 96.0% of the cases. Upon follow-up for 3-6 months, complete remission was seen in 96.0% of the treated patients. No significant complication was found in all patients. Percutaneous trans-catheter intervention is a useful approach for the diagnosis and treatment of malignant pericardial effusion.

[Detection of herpes viral genome in corneal buttons of quiescet herpes simplex keratitis with polymerase chain reaction]

PURPOSE

Herpetic keratitis is one of the major cause of blindness. The recent reports have proposed that the herpetic viruses may persist in cornea but provided noconclusive evidence. This study is to determine whether the cornea is another latent site of herpes simplex virus.

METHODS

18 corneal buttons of patients with quiescent herpes simplex keratitis which had quited for at least three months (mean 3.7 years) and were obtained by corneal transplantation were detected using polymerase chain reaction (PCR). The sequences of the primers are: P15'CATCACCGACCCGGAGAGGGAC, P25'GGGCCAGGCGCTTGTTGGTGTA.

RESULTS

The positive HSV DNA were found in 17 corneal buttons out of 18 cases.

CONCLUSION

The HSV genomes are present in the cornea of quiescent herpetic keratitis, which suggest that the cornea may be another latent site of herpetic virus. The PCR is a simple, specific and sensitive way to detect HSV genomes in cornea.

[Study on human gamma-crystallins: V. Non-enzymatic glycation of fetal lens gamma 1- and gamma 3-crystallins in vitro]

PURPOSE

To compare the non-enzymatic glycation of different human fetal gamma-crystallins induced by glucose and fructose.

METHODS

gamma 1- and gamma 2-crystallin were separated by the Sephadex gel chromatography from human fetal lenses. The non-enzymatic glycations of these gamma-crystallins were conducted by incubating with glucose or fructose at 37 degrees C for 20 days. The opacity and pellet formation as well as changes on SDS-polyacrymide gel electrophoresis (SDS-PAGE) pattern and blue fluorescence production were observed.

RESULTS

Although the two gamma-crystallins displayed similar alterations, gamma 1-crystallin was easier to produce aggregation and insolublization in early stage (i.e. 3 days). SDS-PAGE showed that there were aggregates, formed through disulfide and non-disulfide cross-links, and degraded peptides produced. The blue fluorescence increased in glycated gamma 3-crystalline solution. Fructose had more significant effects (i.e. aggregation, degradation, producing blue fluorescence) on gamma-crystallins as compared with glucose.

CONCLUSION

Human fetal gamma 1- and gamma 3-crystallins are sensitive, at different extent (gamma 1 > gamma 3), to response to non-enzymatic glycation, and fructose has stronger effect than glucose on the glycation.

Computerized microimage analysis of age-related changes of the human sinoatrial node

This paper reports the age-related changes in the histological features of the sinoatrial node (SAN). The hearts of 106 persons dying at different ages (2 days-83 years), without clinical or pathological evidence of cardiac disease, were taken and divided into seven age-groups. Serial sections with a thickness of 2 microns, parallel to the long axis of the SAN, were prepared. Sections with the maximal area of the SAN were stained with hematoxylin/eosin (H & E) and Betty's method. The largest area of SAN were calculated by a computerized microimage analysis system. The age-related changes of the human SAN were discussed.

Proton nuclear magnetic resonance studies on huwentoxin-I from the venom of the spider Selenocosmia huwena: 1. Sequence-specific 1H-NMR assignments

The complete sequence-specific assignments of resonances in the 1H-NMR spectrum of huwentoxin-I from the Chinese bird spider, Selencocosmia huwena, is described. A combination of two-dimensional NMR experiments including 2D-COSY, 2D-NOESY, and 2D-TOCSY has been employed on samples of the toxin dissolved in D2O and in H2O for assignment purposes. Protons belonging to spin systems for each of the 33 amino acids were identified. The sequence-specific assignments were facilitated by the identification of d alpha N connectivities on the fingerprint regions of the COSY and NOESY spectra and were supported by the identification of dNN and d alpha N connectivities in the TOCSY and NOESY spectra. These studies provide a basis for the determination of the solution-phase conformation of this toxin.