bluuebunny/crossref_metadata_2025 huggingface dataset:
p53 and Ki-67 Proliferating Cell Nuclear Antigen in Benign and Malignant Peripheral Nerve Sheath Tumors in Children
Authors: Liapis Helen , Marley Edith F. , Lin Yuan , Dehner Louis P.
Published: July 2002

Malignant peripheral nerve sheath tumors (MPNSTs) are uncommon soft tissue tumors. In children with neurofibromatosis 1 (NF1), a MPNST often arises in a preexisting neurofibroma, or may represent an initial manifestation without other obvious stigmata of the disease. The development of MPNSTs may be associated with instability of the p53 tumor suppressor gene since it is the most frequent genetic abnormality in soft tissue sarcomas. To assess the presence of p53 accumulation in MPNSTs and its correlation with clinical and pathologic features, we studied 12 neurofibromas (NFs), including 4 tumors with cellular features (one congenital) and 10 MPNSTs. Six MPNSTs were associated with NF1, all of which developed within a plexiform neurofibroma. Cell proliferation evaluated with an antibody to Ki-67 and nuclear p53 staining were both detected by immunohistochemistry We found p53 positivity in 60% of MPNSTs. All NFs except the congenital tumor were p53 immunonegative ( P < 0.01). Rare p53-positive nuclei were detected in the transitional zone in two of six MPNSTs arising in plexiform NFs. Ki-67 distinguished the NFs from MPNSTs ( P < 0.005). Half of the NF1 patients with p53-positive MPNSTs developed recurrence or metastases or developed a second malignancy within 2 years of diagnosis, whereas patients with p53-positive sporadic MPNSTs were free of disease 1 to 7 years later. We found p53 accumulation more frequently in NF1-associated MPNSTs. p53 mutations may be an additional biologic factor to account for the poor prognosis in these tumors.
Vocal Cord Basement Membrane in Non-Sudden Infant Death Syndrome Cases
Authors: Castro Eumênia C.C. , Peres L. Cesar
Published: July 2002

Vocal cord basement membrane thickening (VCBMT) has been observed in children with sudden infant death syndrome (SIDS). It has been proposed that this lesion could be used as a positive indicator of this syndrome in autopsies of children who have died unexpectedly. The present investigation aimed to analyze vocal cord basement membranes from autopsies of children 0 to 365 days old. A total of 134 larynges were analyzed. Histological sections of paraffin-embedded larynges stained with H&E and submitted to histochemical staining with periodic acid–Schiff (PAS), Masson's trichrome, syrius red, and Carstairs were used for light microscopy analysis. Immunohistochemistry with monoclonal anti-collagen IV antibody was used to determine the nature of VCBMT. The study was completed with morphometry of H&E–and PAS-stained sections and revision of the clinical information contained in the hospital files. VCBMT was found in 25 cases (18.7%) and showed characteristics of normal basement membrane, including immunoreactivity to collagen IV. Our data support the conclusions that VCBMT is frequently seen in pediatric autopsies, is seen in children in all age-groups studied whose deaths were due to causes other than SIDS, and is commonly associated with infectious diseases. Like SIDS, VCBMT occurs in the first year of life.
Early Death of Neural Crest Cells is Responsible for Total Enteric Aganglionosis in Sox10Dom/Sox10Dom Mouse Embryos
Authors: Kapur Raj P.
Published: July 2002

Intestinal aganglionosis results from homologous genetic defects in humans and mice, including mutations of Sox10, which encodes a transcription factor expressed in neural crest cells. To gain insight into the embryological basis for this condition, the phenotype and pathogenesis of intestinal aganglionosis in Sox10 Dom/ Sox10 Dom embryos were studied. The distribution of enteric neural precursors and other neural crest derivatives in Sox10 Dom/ Sox10 Dom embryos was analyzed with immunochemical and transgenic markers. The ability of wild-type neural crest cells to colonize Sox10 Dom/ Sox10 Dom intestinal ex-plants was evaluated by appositional grafts under the renal capsule. Apoptosis was studied by TUNEL labeling. Sox10 Dom/ Sox10 Dom embryos died pre- or perinatally with total enteric aganglionosis and hypoplasia or agenesis of nonenteric ganglia. Mutant crest cells failed to colonize any portion of the Sox10 Dom/ Sox10 Dom gut, but wild-type neural crest cells were able to colonize explanted segments of Sox10 Dom/ Sox10 Dom embryonic intestine. In Sox10 Dom/ Sox10 Dom embryos, apoptosis was increased in sites of early neural crest cell development, before these cells enter the gut. Sox10 Dom/ Sox10 Dom embryos are one of many genetic animal models for human Hirschsprung disease. The underlying problem is probably not the enteric microenvironment, since Sox10 Dom/ Sox10 Dom intestine supports colonization and neuronal differentiation by wild-type neural crest cells. Instead, excessive cell death occurs in mutant neural crest cells early in their migratory pathway. Comparison with other models suggests that genetic heterogeneity of aganglionosis correlates with different pathogenetic mechanisms.
Desmoplastic Infantile Ganglioglioma
Authors: Craver Randall D. , Nadell Joseph , Nelson James S.
Published: July 2002

We present the clinical, anatomic, and laboratory findings in a 4-month-old child with desmosplastic infantile ganglioglioma. Microtubule-associated protein-2 (AP18) and neuron-specific B-tubulin (TUJ-1) were more sensitive in detecting immature neural elements than synaptophysin. Despite the immature neuroblastic component, focal intermediate proliferation indices, microinvasion, presence of secondary features (extension into Virchow Robin spaces, perineuronal satellitosis), and subtotal resection, the child has done well, with striking improvement of the magnetic resonance imaging (MRI) image, head size improvement, no tumor recurrence, and minimal neurological deficits.
Childhood Lichen Scrofulosorum Revisited
Authors: Ramdial Pratistadevi K. , Mosam Anisa , Pillay Thillagavathie , Mallett Renee , Aboobaker Jamilla
Published: July 2002

Lichen scrofulosorum (LS), an uncommon cutaneous tuberculous reaction, has been described in children and young adults. In the last three decades, there has been a dearth of literature on the entity in children, despite a global increase in tuberculosis. It is usually associated with localized cervical, hilar, or mediastinal lymphadenopathy or with osseous tuberculosis. The occurrence of LS in association with pulmonary tuberculosis is rare and its occurrence with generalized lymphadenopathy is unrecognized. We report LS in two children and highlight its occurrence with pulmonary tuberculosis and generalized lymphadenopathy.
Anomalous Costochondral Cartilage in Fetal Anencephaly
Authors: Garcia-Ramirez Marta , Toran Nuria , Carrascosa Antonio , Audi Laura
Published: July 2002

Anencephaly is a human fetal malformation with absence of brain and calvarium superior to the orbits. The consequent absence of hypothalamus provides a unique model for studying human development, and therefore skeletal growth, in the absence of hypothalamic hormones and their regulatory functions. To assess the influence of hypothalamic insufficiency on cartilage development, we studied costochondral cartilage sections from eight anencephalic fetuses (18–22 weeks old) and seven controls (16–22 weeks old) with pathologies not directly related to skeletal growth. We found a previously undescribed anomalous organization of the cartilage in the anencephalic. The proliferative chondrocytes showed a disordered appearance with an increased proliferative zonal length (156 ± 28 μm in anencephalic fetuses vs. 103 ± 14 μm in controls, p = 0.006) and a concomitant decrease in the maturing portion, where cells form ordered isogenic groups (58 ± 13 μm in anencephalic fetuses vs. 93 ± 19 μm in controls, p = 0.003). In addition, cell density was significantly decreased in the proliferating and maturing zones in the anencephalic cases (84 ±21 vs. 130 ± 21 cells/40 μm2 in proliferating zone; 53 ± 8 vs. 94 ± 8 in maturing portion, p < 0.005). These alterations in the developing cartilage of the anencephalic may contribute to the observed growth retardation in these fetuses and reflect modifications in pituitary hormones and growth factors resulting from reduction in hypothalamopituitary function.
Computer simulation of stochastic processes through model‐sampling (Monte Carlo) techniques
Authors: Sheppard C.W.
Published: July 2002

A simple Monte Carlo simulation program is outlined which can be used for the investigation of random‐walk problems, for example in diffusion, or the movement of tracers in the blood circulation. The results given by the simulation are compared with those predicted by well‐established theory, and it is shown how the model can be expanded to deal with drift, and with reflexion from or adsorption at a boundary.
Interaction of GRF with VIP receptors and stimulation of adenylate cyclase in rat and human intestinal epithelial membranes
Authors: Laburthe M. , Amiranoff B. , Boige N. , Rouyer-Fessard C. , Tatemoto K. , Moroder L.
Published: July 2002

GRF (10−8–10−5 M) is shown to inhibit competitively the binding of [125I]VIP to human and rat intestinal epithelial membranes. The affinity of GRF for VIP receptor is 700–800‐times lower than that of VIP in both species. The order of affinity of different peptides is VIP > PHI > secretin > GRF in rat, and VIP > GRF > PHI > secretin in man. The important species specificity of VIP receptors in recognizing PHI and secretin does not occur in the case of GRF. GRF stimulates adenylate cyclase through its interaction with VIP receptors in rat and human membranes. However, while GRF behaves as a VIP agonist in human tissue, it is a partial agonist/antagonist of VIP in the rat.
Identification by cross‐linking of a neuronal acceptor protein for dendrotoxin, a convulsant polypeptide
Authors: Mehraban Fuad , Breeze Alexander L. , Dolly J.Oliver
Published: July 2002

Dendrotoxin, a lijow molecular weight protein from the venom of Dendroaspis angusticeps, is known to be a potent convulsant that attenuates one type of voltage‐sensitive K+ channel in guinea‐pig hippocampus. A biologically active preparation of 125I‐labelled dendrotoxin has been cross‐linked to its high‐affinity protein acceptor in synaptic plasma membranes from rat cerebral cortex. On SDS gel electrophoresis, a complex with a Mr of 72,000 was observed which, assuming one toxin molecule is attached, yields an apparent size of 65,000 for this subunit of the acceptor. Unlike dendrotoxin, low concentrations of β‐bungarotoxin, another pre‐synaptically acitve toxin, do not inhibit its labelling.
Structural study of hemoglobin Hazebrouck, β38(C4)Thr → Pro
Authors: Blouquit Y. , Delanoe-Garin J. , Lacombe C. , Arous N. , Cayre Y. , Peduzzi J. , Braconnier F. , Galacteros F.
Published: July 2002

A new β‐variant has been detected and structurally defined in a French male, with a life‐long history of hemolytic anemia. This variant is moderately unstable and has a low oxygen affinity. The abnormal hemoglobin was not detected by standard electrophoretic procedures. It moved slightly slower than Hb A during isoelectric focusing (IEF). Two minor fractions were also seen; the first migrated just cathodal to Hb F, as did partially oxidized Hb A or hemichrome derivatives of some unstable hemoglobins; the second in the position of free α‐chains. The abnormal β‐chain was readily separated from both βa‐ and αa‐chains by acid‐urea‐Triton globin chain electrophoresis. Structural study was conducted simultaneously by fingerprinting and high‐performance liquid chromatography (HPLC) of tryptic peptides. A new mutation β38(C4)Thr → Pro was found, which was named Hb Hazebrouck.
Resonance Raman characterization of the heme prosthetic group in eosinophil peroxidase
Authors: Sibbett Scott S. , Klebanoff Seymour J. , Hurst James K.
Published: July 2002

The resonance‐enhanced Raman spectrum of eosinophil peroxidase (EPO) from horse and human eosinophils is reported. Based upon the spectral energies, distribution and depolarization ratios of the high‐frequency skeletal modes and upon the presence of weak bands assignable to vinyl substituent groups, we conclude that the heme prosthetic group is high‐spin, 6 coordinate protoporphyrin. The Raman spectrum reveals clear differences from lactoperoxidase (LPO), an enzyme which appears nearly structurally isomorphous by other physical techniques; the data indicate a stronger axial 6th ligand in EPO. Mechanistic implications are discussed in relation to LPO and myeloperoxidase, an enzyme present in neutrophils and monocytes which contains a unique functional active‐site chlorin.
Rohdei‐litorin: a new peptide from the skin of Phyllomedusa rohdei
Authors: Barra D. , Erspamer G.Falconieri , Simmaco M. , Bossa F. , Melchiorri P. , Erspamer V.
Published: July 2002

Rohdei‐litorin
Amino acid sequencing
Amphibian skin
Neuromedin
Involvement of Ca2+ in platelet‐derived growth factor‐induced expression of c‐myc oncogene in Swiss 3T3 fibroblasts
Authors: Tsuda Terutaka , Kaibuchi Kozo , West Brian , Takai Yoshimi
Published: July 2002

Addition of platelet‐derived growth factor (PDGF) to quiescent cultures of Swiss 3T3 fibroblasts rapidly increased the cytoplasmic free Ca2+ concentrations and afterwards the c‐myc mRNA levels. The concentrations of PDGF needed for both reactions were roughly the same. Moreover, the Ca2+ ionophores, A23187 and ionomycin, mimicked the actions of PDGF and increased the c‐myc mRNA levels. These results suggest that Ca2+ may be involved in the regulation of PDGF‐induced expression of the c‐myc gene.
Modulation of DNA methyltransferase during the life cycle of a mealybug Planococcus lilacinus
Authors: Devajyothi C. , Brahmachari Vani
Published: July 2002

The levels of de novo DNA methyltransferase were studied during the development of a mealybug, Planococcus lilacinus. No enzyme activity could be detected in extracts from second instar females. But the enzyme occurs at high levels in third instar females and is maintained at that level during fourth instar when gametogenesis, fertilization and chromosome imprinting occur. These results suggest a developmental stage‐specific modulation of levels of DNA methyltransferase. Assays with synthetic polymers showed that the enzyme can methylate not only polymers containing GpG but also those containing CpA and CpI.
Sucrose‐phosphate synthase is dephosphorylated by protein phosphatase 2A in spinach leaves
Authors: Siegl Gabriele , MacKintosh Carol , Stitt Mark
Published: July 2002

Sucrose‐phosphate synthase (SPS) purified from spinach leaves harvested in the dark, was activated by mammalian protein phosphatase 2A (PP2A). Activation of SPS in a fraction from darkened spinach leaves was largely prevented by either okadaic acid or microcystin‐LR (specific inhibitors of PP1 and PP2A), while inhibitor‐2 (a PP1 inhibitor) or Mg2+ (essential for PP2C) were ineffective. In vivo, okadaic add and microcystin‐LR prevented the light‐induced activation of SPS and decreased sucrose biosynthesis and CO2 fixation. It is concluded that PP2A is the major SPS phosphatase in spinach. This study is the first to employ microcystin‐LR for modulating protein phosphorylation in vivo.
Identical genes for trimethoprim‐resistant dihydrofolate reductase from Staphylococcus aureus in Australia and Central Europe
Authors: Burdeska Alexander , Ott Michael , Bannwarth Willi , Then Rudolf L.
Published: July 2002

The nucleotide sequence of a 1.25 kb BglII/EcoRI fragment from the 34 kb trimethoprim (Tp)‐resistant plasmid pABU1 of Staphylococcus aureus 157/4696, isolated in Zürich, was determined. It contained the entire Tp‐resistant dihydrofolate reductase gene, 197 bp of the thymidylate synthetase, 395 bp of a truncated gene and 111 bp of IS257R1. With the exception of one single base pair at position 862 the sequence of the whole fragment was identical to nucleotides 1633 to 2885 of the Tp‐resistant transposon Tn4OO3 in plasmid pSK 1 from an Australian S. aureus isolate. This suggests the worldwide dissemination of Tn4OO3 in multiresistant Staphylococci.
Molecular cloning and expression of the human melanocyte stimulating hormone receptor cDNA
Authors: Chhajlani Vijay , Wikberg Jarl E.S.
Published: July 2002

Melanocytes and melanoma cells are known to possess receptors for melanocyte stimulating hormone (MSH). A cDNA clone, designated IID, has been isolated from human melanoma cells and encodes a MSH receptor. The cloned cDNA encodes a 317 amino acid protein with transmembrane topography characteristics of a G‐protein‐coupled receptor, but it does not show striking similarity to already published sequences of other G‐protein‐coupled receptors. When IID cDNA is expressed in COS‐7 cells, it binds an 125I‐labelled MSH analogue (NDP‐MSH) in a specific manner. The bound ligand could be displaced by melanotropic peptides, α‐MSH, β‐MSH, γ‐MSH and ACTH (adrenocorticotropic hormone), but not by the non‐melanotropic peptide, β‐endorphine. This is the first report of the cloning of a receptor gene of the melanotropin receptor family.
ATP‐dependent protein refolding activity in reticulocyte lysate
Authors: Nimmesgern Elmar , Hartl F.Ulrich
Published: July 2002

The protein folding capacity of rabbit reticulocyte cytosol was analyzed using the renaturation of firefly luciferase as a sensitive assay. In the absence of ATP, the aggregation of denatured luciferase diluted into reticulocyte lysate was prevented. Chaperone‐stabilized luciferase was detected in high molecular weight complexes overlapping the distributions of Hsc70, Hsp90 and the chaperonin TRiC on gel filtration columns. The readdition of unfractionated cytosol and Mg‐ATP was required for the efficient folding of these forms of luciferase to the active enzyme. We conclude that protein folding in the eukaryotic cytosol depends on the functional cooperation of different chaperone activities and cofactors in a complex, ATP‐dependent process.
Subunit structure of ATP synthase from chloroflexus aurantiacus
Authors: Yanyushin Mikhail F.
Published: July 2002

An ATP synthase has been isolated from green nonsulfur photosynthetic bacterium Chloroflexus aurantiacus, a representative of a lower branch of eubacteria. The enzyme, reconstituted with the bacterial lipids into proteoliposomes, is shown to catalyze [32P]Pi‐ATP exchange (at a rate of 180 nmol [32P]ATP/). The ATP synthase is composed of nine polypeptide species (60, 50, 33, 19, 16.5, 15.5, 14.5, 13, and 8 kDa as determined by urea‐SDS‐PAGE). The catalytic part of the ATP synthase (which is detached by chloroform treatment) contains the first four polypeptides. In the intact ATP synthase the 14.5 and 13 kDa polypeptides are connected by disulfide bonds to form a heterodimer of 25 kDa.
Expression of β subunit isoforms of the Na+,K+‐ATPase is muscle type‐specific
Authors: Hundal Harinder S. , Marette André , Ramlal Toolsie , Liu Zhi , Klip Amira
Published: July 2002

Hindlimb skeletal muscles of the rat express two isoforms of the α (αl and α2) and two isoforms of the β (β1 andβ2) subunits of the Na+,K+‐ATPase. Because several muscles constitute the hindlimb, we investigated if specific isoforms are expressed in particular muscles. Northern blot analysis using isoform‐specific cDNA probes demonstrated that soleus muscle expressed only the β1 transcript, whereas EDL or white gastrocnemius muscles expressed only the β2 transcript, and red gastrocnemius muscle expressed both mRNAs. All muscles tested expressed both α1 and α2 transcripts, albeit to various degrees: α1 transcripts were present to about the same extent in all muscles but α2 mRNA was 4‐fold more abundant in soleus than in EDL for the same amount of total RNA. β subunit protein levels were investigated in purified plasma membrane fractions of pooled red (soleus + red gastrocnemius + red quadriceps) or white (white gastrocnemius + white quadriceps) muscles using isoform‐specific antibodies. Red muscles expressed mostly the β1 protein while white muscles expressed mostly the β2 subunit. Both muscle groups had similar levels of α1 or α2 subunits, and crude membranes isolated from red muscles had 30% higher Na+,K+‐ATPase activity than white muscle membranes. We conclude that oxidative muscles (slow and fast twitch) express β1 subunits, whereas glycolytic, fast twitch muscles express β2 subunits, and that both β isoforms support the Na+,K+‐ATPase activity of the a subunits.
Structure and dynamics of bacteriorhodopsin
Authors: Ferrand M. , Zaccai G. , Nina M. , Smith J.C. , Etchebest C. , Roux B.
Published: July 2002

Global features of the structure and dynamics of bacteriorhodopsin are investigated using molecular modelling, dynamical simulations and neutron scattering experiments. The simulations are performed on a model system consisting of one protein molecule plus intrinsic water molecules. The simulation‐derived structure is compared with neutron diffraction data on the location of water and with the available electron microscopy structure of highest resolution. The simulated water geometry is in good accord with the neutron data. The protein structure deviates slightly but significantly from the experiment. The low‐frequency vibrational frequency distribution of a low‐hydration purple membrane is derived from inelastic neutron scattering data and compared with the corresponding simulation‐derived quantity.
Differential tissue expression of Annexin VIII in human
Authors: Reutelingsperger Chris P.M. , van Heerde Waander , Hauptmann Rudolf , Maassen Cecile , van Gool Reinoud G.J. , de Leeuw Peter , Tiebosch Anton
Published: July 2002

The expression of Annexins V and VIII by human lung, liver, kidney, skin, heart, uterus, spleen and skeletal muscle was investigated by ELISA. All investigated tissues contained Annexin V. Its level varied with the tissue from around 5 μg (skin) to approximately 120 μg (spleen) per g of wet tissue. Contradistinctionally Annexin VIII expression was less ubiquitous and less abundant. Only lung, skin, liver and kidney expressed Annexin VIII. Its levels were approximately 100‐fold less then the Annexin V levels. Immunohistochemical analysis of lung sections revealed Annexin VIII presence exclusively in the endothelia. Annexin V and VIII levels of cultured human umbilical vein endothelial cells, human arterial smooth muscle cells, human lung fibroblasts and HeLa cells were measured by ELISA. All cell types expressed Annexin V whereas only HeLa cells had detectable levels of Annexin VIII. The results indicate a tissue specific expression of Annexin VIII by lung endothelium, suggesting a highly specialised function.
The human ubiquitin‐conjugating enzyme UbcH1 is involved in the repair of UV‐damaged, alkylated and cross‐linked DNA
Authors: Kaiser Peter , Mansourl Hamdy A. , Greeten Tim , Auer Bernhard , Schweiger Manfred , Schneider Rainer
Published: July 2002

The human ubiquitin‐conjugating enzyme UbcH1 shows 69% identity to the Saccharomyces cerevisiae RAD6/UBC2 which plays a key role in DNA repair. To examine the function of UbcH1 (formerly named E2, M, 17 000), [(1990) EMBO J. 9, 1431–1435]) we tested its ability to functionally substitute for yeast RAD6/UBC2 in the recovery of cells from various DNA damage. Complementation by expression of the human UbcH1 cDNA revealed that the UbcH1 carries out the function of S. cerevisiae RAD6/UBC2 in the repair of UV‐damaged, alkylated and cross‐linked DNA.
T‐type Ca2+ channels and α1E expression in spermatogenic cells, and their possible relevance to the sperm acrosome reaction
Authors: Liévano Arturo , Santi Celia M. , Serrano Carmen.J. , Treviño Claudia L. , Bellvé Anthony R. , Hernández-Cruz Arturo , Darszon Alberto
Published: July 2002

There is pharmacological evidence that Ca2+ channels play an essential role in triggering the mammalian sperm acrosome reaction, an exocytotic process required for sperm to fertilize the egg. Spermatozoa are small terminally differentiated cells that are difficult to study by conventional electrophysiological techniques. To identify the members of the voltage‐dependent Ca2+ channel family possibly present in sperm, we have looked for the expression of the α
1A, α
1B, α
1C, α
1D and α
1E genes in mouse testis and in purified spermatogenic cell populations with RT‐PCR. Our results indicate that all 5 genes are expressed in mouse testis, and in contrast only α
1E, and to a minor extent α
1A, are expressed in spermatogenic cells. In agreement with these findings, only T‐type Ca2+ channels sensitive to the dihydropyridine nifedipine were observed in patch‐clamp recordings of pachytene spermatocytes. The results suggest that low‐threshold Ca2+ channels are the dihydropyridine‐sensitive channels involved in the sperm acrosome reaction.
Surgical classification of obstetric fistulas
Authors: Waaldijk K.
Published: July 2002

Objective: To develop a surgical classification for obstetric fistulas in order to compare surgical techniques and results. Methods: Based on a retrospective analysis of 775 consecutive fistula patients, the following classification is presented: (type I) fistulas not involving the urethral closing mechanism; (type II) fistulas involving the urethral closing mechanism; and (type III) ureter and other exceptional fistulas. Type II fistulas can be further divided into: (A) without (sub)total urethra involvement, and (B) with (sub)total urethra involvement; and (a) without a circumferential defect, and (b) with a circumferential defect. This classification was applied prospectively in over 2700 consecutive fistula patients. Results: The surgical technique becomes progressively more complicated from type I through type IIBb. The results of closure and continence worsen progressively from type I through type IIBb. Personal experience in the case of type III fistulas is very limited. Conclusion: This classification enables a systematic comparison of different surgical techniques and an objective evaluation of results from different centers.
Dietary flavonoid and isoflavone glycosides are hydrolysed by the lactase site of lactase phlorizin hydrolase
Authors: Day Andrea J , Cañada F.Javier , Dı́az Juan C , Kroon Paul A , Mclauchlan Russell , Faulds Craig B , Plumb Geoff W , Morgan Michael R.A , Williamson Gary
Published: July 2002

Lactase phlorizin hydrolase (LPH; EC 3.2.1.62) is a membrane‐bound, family 1 β‐glycosidase found on the brush border of the mammalian small intestine. LPH, purified from sheep small intestine, was capable of hydrolysing a range of flavonol and isoflavone glycosides. The catalytic efficiency (k
cat/K
m) for the hydrolysis of quercetin‐4′‐glucoside, quercetin‐3‐glucoside, genistein‐7‐glucoside and daidzein‐7‐glucoside was 170, 137, 77 and 14 (mM−1 s−1) respectively. The majority of the activity occurred at the lactase and not phlorizin hydrolase site. The ability of LPH to deglycosylate dietary (iso)flavonoid glycosides suggests a possible role for this enzyme in the metabolism of these biologically active compounds.
Chaperone‐like activity of synucleins
Authors: Souza José M. , Giasson Benoit I. , Lee Virginia M.-Y. , Ischiropoulos Harry
Published: July 2002

Synucleins are a family of small proteins that are predominantly expressed in neurons. The functions of the synucleins are not entirely understood, but they have been implicated in the pathogenesis of several neurodegenerative diseases. Our data show that α‐, β‐ or γ‐synuclein suppresses the aggregation of thermally denatured alcohol dehydrogenase and chemically denatured insulin. The A53T but not the A30P mutant α‐synuclein was able to inhibit the aggregation of insulin and the chaperone‐like activity of α‐synuclein was lost upon removal of its C‐terminal residues 98–140. These results demonstrate that synucleins with the exception of the A30P mutant possess chaperone‐like activity.
Calpain‐mediated degradation of p35 to p25 in postmortem human and rat brains
Authors: Taniguchi S. , Fujita Y. , Hayashi S. , Kakita A. , Takahashi H. , Murayama S. , Saido T.C. , Hisanaga S. , Iwatsubo T. , Hasegawa M.
Published: July 2002

Tau in Alzheimer neurofibrillary tangles has been shown to be hyperphosphorylated and CDK5, GSK3, MAP kinase and SAP kinases are the candidate kinases for the phosphorylation of tau. Recently, it was reported that the conversion of p35, the activator of CDK5, to p25 was upregulated in Alzheimer's disease (AD) brains, and that p35 is cleaved to yield p25 by calpain. Here we show that p35 is rapidly cleaved to p25 in rat and human brains within a short postmortem delay and that the conversion of p35 to p25 is partially dependent on calpain activity. Immunoblot analysis of brains prepared from patients with AD or age‐matched control individuals with a short postmortem delay revealed no specific increase in the levels of p25 in AD brains, whereas the levels of active form of calpain were increased in AD brains compared to the those in controls. These observations suggest that the conversion of p35 to p25 is a postmortem degradation event and may not be upregulated in AD brains.
Mechanisms of tetraethylammonium ion block in the KcsA potassium channel
Authors: Luzhkov Victor B , Åqvist Johan
Published: July 2002

We report results from automated docking and microscopic molecular dynamics simulations of the tetraethylammonium (TEA) complexes with KcsA. Binding modes and energies for TEA binding at the external and internal sides of the channel pore are examined utilising the linear interaction energy method. Effects of the channel ion occupancy (based on our previous results for the ion permeation mechanisms) on the binding energies are considered. Calculations show that TEA forms stable complexes at both the external and internal entrances of the selectivity filter. Furthermore, the effects of the Y82V mutation are evaluated and the results show, in agreement with experimental data, that the mutant has a significantly reduced binding affinity for TEA at the external binding site, which is attributed to stabilising hydrophobic interactions between the ligand and the tyrosines.
Comparative mutational analysis of peptidyl prolyl cis/trans isomerases: active sites of Escherichia coli trigger factor and human FKBP12
Authors: Tradler Thomas , Stoller Gerlind , Rücknagel Karl P , Schierhorn Angelika , Rahfeld Jens-U , Fischer Gunter
Published: July 2002

A low degree of amino acid sequence similarity to FK506‐binding proteins (FKBPs) has been obtained for the peptidyl prolyl cis/trans isomerase (PPIase) domain of E. coli trigger factor (TF) that was thought to be significant with regard to the enzymatic properties of the bacterial enzyme. We examined whether the alteration of a negatively charged side‐chain at position 37 (FKBP numbering) and a phenylalanine at position 99, both highly conserved through both types of enzymes, leads to parallel effects on the catalytic activity of both FKBP12 and TF‐PPIase domain in a series of tetrapeptide substrates with different P1 subsites. For the latter enzyme, substitution of Glu178 by Val or Lys, which aligns to Asp37 in human FKBP12, enhanced the PPIase activity, whereas a strongly decreased enzymatic activity was determined for the Asp37Leu and Asp37Val variants of FKBP12. Regardless of the P1 subsite of the substrate used for the assay, mutation of Phe233Tyr generated a protein variant of the TF‐PPIase domain with about 1% of the wild type PPIase activity. Dependent on the substrate nature, a moderate decrease as well as a 4.8‐fold increase in k
cat/K
M could be determined for the corresponding Phe99Tyr FKBP12 variant. Neither of the mutations of the TF‐PPIase domain was able to implant FK506 inhibition found as a major characteristic of the FKBP family of PPIases.
Sphingosine‐mediated electroporative DNA transfer through lipid bilayers
Authors: Hristova Nadejda I , Tsoneva Iana , Neumann Eberhard
Published: July 2002

When the cationic sphingosine is present in planar lipid bilayers, the adsorption of pDNA is enhanced and the electroporatability of the bilayer is facilitated. Furthermore, pDNA, adsorbed to lipid bilayers composed of diphytanoyl lecithin and d‐sphingosine causes electroporative channel‐like events of conductance 1 to 7 pS, provided the voltage polarity is correct and the voltage is high enough, V
m≥+30 mV. The data suggest electrotransport of pDNA through the bilayer, mediated by transient complexes between DNA and the lipids in the pore edges of elongated, electropercolated hydrophilic pore zones. The results are the basis for the optimisation of electroporative transfer of DNA or oligonucleotides to cells and tissue.
Calcium‐dependence of hydrogen peroxide‐induced c‐fos expression and growth stimulation of multicellular prostate tumor spheroids
Authors: Sauer Heinrich , Diedershagen Heike , Hescheler Jürgen , Wartenberg Maria
Published: July 2002

Hydrogen peroxide (H2O2) in nanomolar concentrations (20–100 nM) stimulated the growth of small (diameter 100±30 μm) multicellular prostate cancer spheroids and increased c‐fos expression. H2O2 transiently raised [Ca2+]i by Ca2+ release from intracellular stores as the transient persisted in low (10 nM) Ca2+ solution but was abolished when intracellular Ca2+ stores were depleted by thapsigargin or chelation of [Ca2+]i with BAPTA. The H2O2‐induced [Ca2+]i transient was furthermore inhibited by the P2‐purinoreceptor antagonists suramin and basilen blue, indicating that H2O2 may act via purinergic receptor stimulation. Treatment of spheroids with either suramin, basilen blue or BAPTA inhibited the H2O2‐induced growth stimulation and c‐fos expression, indicating that the H2O2‐mediated growth stimulation of multicellular spheroids is mediated via a Ca2+‐dependent pathway.
Reactivity of β‐carotene towards peroxyl radicals studied by laser flash and steady‐state photolysis
Authors: Mortensen Alan , Skibsted Leif H
Published: July 2002

Peroxyl radicals, as model for peroxyl radicals formed during autoxidation of lipids, have been generated in three solvent systems (cyclohexane, tetrahydrofuran and tert‐butanol/water) by steady‐state and laser flash photolysis, and their reaction with β‐carotene studied. Steady‐state photolysis experiments showed that alkyl, alkoxyl and alkylperoxyl radicals all react with β‐carotene. However, laser flash photolysis experiments indicated that the reaction with peroxyl radicals (second‐order rate constant estimated to be less than 106 M−1 s−1) is slower than with alkyl and alkoxyl radicals, and that β‐carotene is hence a poor direct scavenger of peroxyl radicals. Scavenging of peroxyl radicals by β‐carotene is suggested not to proceed via electron transfer but rather by adduct formation and/or hydrogen abstraction. For different phenoxyl radicals, differences in reactivity towards β‐carotene seem to be correlated with standard reduction potential.
Altered expression of the DNA repair protein, N‐methylpurine‐DNA glycosylase (MPG), in breast cancer
Authors: Cerda Sonia R , Turk Patrick W , Thor Ann D , Weitzman Sigmund A
Published: July 2002

We examined expression of N‐methylpurine‐DNA glycosylase (MPG), a DNA repair enzyme that removes N‐alkylpurine damage, in normal, malignant, and immortalized breast epithelial cells, and breast cancer cell lines (MDA‐MB‐231, MCF7, T47D). Northern analysis showed increased expression in cancer versus normal breast epithelial cells (2–24‐fold). Southern blots revealed no gene amplification or polymorphisms. Immunofluorescence, immunohistochemistry, and Western blot analysis demonstrated increased MPG protein expression in the tumor cells that correlated with elevated glycosylase activity. Since MPG overexpression has been shown to be paradoxically associated with increased susceptibility to DNA damage, up‐regulation of this gene may suggest a functional role in breast carcinogenesis.
Ser‐262 in human recombinant tau protein is a markedly more favorable site for phosphorylation by CaMKII than PKA or PhK
Authors: Sironi Juan J , Yen Shu-Hui , Gondal Javed A , Wu Qiongli , Grundke-Iqbal Inge , Iqbal Khalid
Published: July 2002

Several kinases have been shown to phosphorylate tau protein at Ser‐262, an important site involved in the regulation of the binding of tau to microtubules. In this study we compared the phosphorylation of tau at Ser‐262 by CaMKII, PhK and PKA in vitro as determined by radioimmunoblots developed by the monoclonal antibody 12E8 which recognizes P‐Ser‐262 and P‐Ser‐356; and Ab‐262, a polyclonal antibody which is specific to unphosphorylated Ser‐262 in tau. We found that the phosphorylation at Ser‐262 was several times more effective by CaMKII than PKA or PhK. Employing rat brain extract as a source of all brain kinases and KN‐62, a specific inhibitor of CaMKII, we found that CaMKII accounts for ∼45% of phosphorylation at Ser‐262. Furthermore, in rat brain slices kept metabolically active in oxygenated artificial CSF, phosphorylation of tau at Ser‐262 was (i) increased up to 120% in the presence of bradykinin, a CaMKII activator, and (ii) inhibited by ∼35% in the presence of KN‐62. Thus, CaMKII is a major tau Ser‐262 kinase in mammalian brain.
Various glucocorticoids differ in their ability to induce gene expression, apoptosis and to repress NF‐κB‐dependent transcription
Authors: Hofmann Thomas G , Hehner Steffen P , Bacher Susanne , Dröge Wulf , Schmitz M.Lienhard
Published: July 2002

Glucocorticoids (GCs) influence a great variety of cellular functions by at least three important modes of action: the activation (or repression) of genes controlled by binding sites for the glucocorticoid receptor (GR), the induction of apoptosis in lymphocytes and the recently discovered cross‐talk to other transcription factors such as NF‐κB. In this study we systematically compared various natural and synthetic steroid hormones frequently used as therapeutic agents on their ability to mediate these three modes of action. Betamethasone, triamcinolone, dexamethasone and clobetasol turned out to be the best inducers of gene expression and apoptosis. All GCs including the antagonistic compound RU486 efficiently reduced NF‐κB‐mediated transactivation to comparable extents, suggesting that ligand‐induced nuclear localization of the GR is sufficient for transrepression. Glucocorticoid treatment of cells did not result in elevated IκB‐α expression, but impaired the tumor necrosis factor (TNF)‐α‐induced degradation of IκB‐α without affecting DNA binding of NF‐κB. The structural requirements for the various functions of glucocorticoids are discussed.
Anandamide activates human platelets through a pathway independent of the arachidonate cascade
Authors: Maccarrone Mauro , Bari Monica , Menichelli Adriana , Del Principe Domenico , Finazzi Agrò Alessandro
Published: July 2002

Anandamide (arachidonoylethanolamide, AnNH) is shown to activate human platelets, a process which was not inhibited by acetylsalicylic acid (aspirin). Unlike AnNH, hydroperoxides generated thereof by lipoxygenase activity, and the congener (13‐hydroxy)linoleoylethanolamide, were unable to activate platelets, though they counteracted AnNH‐mediated stimulation. On the other hand, palmitoylethanolamide neither activated human platelets nor blocked the AnNH effects. AnNH inactivation by human platelets was afforded by a high‐affinity transporter, which was activated by nitric oxide‐donors up to 225% of the control. The internalized AnNH could thus be hydrolyzed by a fatty acid amide hydrolase (FAAH), characterized here for the first time.
Schizosaccharomyces pombe UDP‐galactose transporter: identification of its functional form through cDNA cloning and expression in mammalian cells
Authors: Segawa Hiroaki , Ishida Nobuhiro , Takegawa Kaoru , Kawakita Masao
Published: July 2002

The Schizosaccharomyces pombe UDP‐galactose transporter cDNA (SpUGT cDNA), encoding the product of the gms1
+ gene which consists of two exon sequences separated by a 173‐bp intron, was cloned by RT‐PCR. Its product, a hydrophobic protein of 353 amino acid residues resembling its human counterpart, was expressed in the Golgi membranes of UDP‐galactose transporter‐deficient Lec8 cells, and complemented the genetic defect of the mutant cells. This indicated that SpUGT cDNA encodes the functional S. pombe UDP‐galactose transporter. The product of an ORF found in the second exon, which was previously assumed to be the S. pombe UDP‐galactose transporter, thus represents an inactive, truncated form of the SpUGT protein.
Forty‐five year's experience of the treatment of choriocarcinoma and invasive mole
Authors: Song H.Z. , Yang X.Y. , Xiang Y.
Published: July 2002

Our work was begun in 1949, through many yera's effort, several chemicals (such as 6 MP, 5 FU and others) were found to be effective for the treatment of choriocarcinoma (C.C.) and invasive mole (I.M.). From 1959 through 1985, 1500 patients were consecutively treated. The mortality rate of CC was reduced from > 90% to < 20%. No more death occurred in IM. All Survivors followed up for 10–38 years showed no evidence of residual disease. 80% of the young patients treated with chemotherapy alone conceived after recovery. The pregnancy outcome showed no deviation from that of the general population. All children are growing up normally many married and gave birth to normal third generations. The results indicated that chemotherapy with 5 FU achieves not only a complete remission, but also a cure, even with wide‐spread metastases. The results of choriocarinoma and invasive mole treated with mainly 5 FU were reported. The clinical experience in the management of metastases at different sites were also summarized.
Sonoactivated Chemodynamic Therapy: A Robust ROS Generation Nanotheranostic Eradicates Multidrug‐Resistant Bacterial Infection
Authors: Song Menglin , Cheng Yi , Tian Ye , Chu Chengchao , Zhang Chang , Lu Zhixiang , Chen Xiaoyuan , Pang Xin , Liu Gang
Published: September 2020

Although ultrasound‐based therapeutic strategies have achieved great success in the battle against antibiotic‐resistant bacterial infections, various sonodynamic treatments still suffer from poor therapeutic efficiency, failing to completely eradicate infections. Thus, more potent strategies are urgently required. Herein, a novel ultrasound‐driven treatment modality, sonoactivated chemodynamic therapy (SCDT), is proposed, which shows a robust generation of superoxide anion and destructive hydroxyl radical via sonotriggered catalytic reactions. This SCDT platform is prepared by grafting Fe3+ onto polyethylenimine‐modified bismuth oxybromide (BiOBr) nanoplates. During sonocatalysis, the introduction of Fe3+ can effectively separate the holes (h+) and electrons (e‐) of BiOBr NPs and shorten their transport path of valence electrons, resulting in the activation of multioxygen reduction and Fenton reaction to generate abundant reactive oxygen species against methicillin‐resistant Staphylococcus aureus (MRSA) infection. More importantly, Fe3+ can also serve as a magnetic resonance imaging (MRI) contrast agent to achieve the accurate diagnosis of bacterial infection. The SCDT‐mediated bactericidal outcome can be monitored by in situ monitoring through MRI technique, revealing a complete elimination of MRSA myositis in mice. Collectively, its deep tissue penetration, high therapeutic efficacy, and noninvasive properties make SCDT a promising therapeutic modality for combating multidrug‐resistant bacterial infection.
Crystalline Naphthylene Macrocycles Capturing Gaseous Small Molecules in Chiral Nanopores
Authors: Matsuno Taisuke , Fukunaga Kengo , Kobayashi Shuhei , Sarkar Parantap , Sato Sota , Ikeda Takuji , Isobe Hiroyuki
Published: September 2020

A series of chiral naphthylene macrocycles, [n]cyclo‐epi‐naphthylenes ([n]CeNAPs), possessing epi‐linkages were synthesized by one‐pot macrocyclization. With chiral (R)‐ or (S)‐1,1′‐linkages embedded in binaphthyl precursors, the macrocycles were assembled in polygonal structures possessing chiral hinges as corners. Among four chiral [n]CeNAP variants, [8]CeNAP with eight naphthylene panels formed robust columnar assemblies in crystals. The nanoporous crystals maintained a columnar assembly structure even after the removal of encapsulated solvent molecules, and their gas adsorption behavior was thoroughly investigated. Gas adsorption, including state‐of‐the‐art in situ crystallographic analyses, revealed accurate atomic‐level structures of the nanopores trapping gaseous N2 molecules in chiral C2 arrangements. With macrocycles as basic frameworks, functional nanopores may be exploited for chiral small‐molecule alignments.
Atypical Emotional Electrodermal Activity in Toddlers with Autism Spectrum Disorder
Authors: Vernetti Angelina , Shic Frederick , Boccanfuso Laura , Macari Suzanne , Kane‐Grade Finola , Milgramm Anna , Hilton Emily , Heymann Perrine , Goodwin Matthew S , Chawarska Katarzyna
Published: September 2020

Past studies in autism spectrum disorder (ASD) indicate atypical peripheral physiological arousal. However, the conditions under which these atypicalities arise and their link with behavioral emotional expressions and core ASD symptoms remain uncertain. Given the importance of physiological arousal in affective, learning, and cognitive processes, the current study examined changes in skin conductance level (ΔSCL) in 41 toddlers with ASD (mean age: 22.7 months, SD: 2.9) and 32 age‐matched toddlers with typical development (TD) (mean age: 21.6 months, SD: 3.6) in response to probes designed to induce anger, joy, and fear emotions. The magnitude of ΔSCL was comparable during anger (P= 0.206,d= 0.30) and joy (P= 0.996,d= 0.01) conditions, but significantly lower during the fear condition (P= 0.001,d= 0.83) in toddlers with ASD compared to TD peers. In the combined samples, ΔSCL positively correlated with intensity of behavioral emotional expressivity during the anger (r[71] = 0.36,P= 0.002) and fear (r[68] = 0.32,P= 0.007) conditions, but not in the joy (r[69] = −0.15,P= 0.226) condition. Finally, ΔSCL did not associate with autism symptom severity in any emotion‐eliciting condition in the ASD group. Toddlers with ASD displayed attenuated ΔSCL to situations aimed at eliciting fear, which may forecast the emergence of highly prevalent internalizing and externalizing problems in this population. The study putatively identifies ΔSCL as a dimension not associated with severity of autism but with behavioral responses in negatively emotionally challenging events and provides support for the feasibility, validity, and incipient utility of examining ΔSCL in response to emotional challenges in very young children.

Lay Summary

Physiological arousal was measured in toddlers with autism exposed to frustrating, pleasant, and threatening tasks. Compared to typically developing peers, toddlers with autism showed comparable arousal responses to frustrating and pleasant events, but lower responses to threatening events. Importantly, physiological arousal and behavioral expressions were aligned during frustrating and threatening events, inviting exploration of physiological arousal to measure responses to emotional challenges. Furthermore, this study advances the understanding of precursors to emotional and behavioral problems common in older children with autism.Autism Res2020, 13: 1476–1488. © 2020 International Society for Autism Research, Wiley Periodicals, Inc.