bluuebunny/crossref_metadata_2025 huggingface dataset:
A methylated human 9-kb repetitive sequence on acrocentric chromosomes is homologous to a subtelomeric repeat in chimpanzees.
Authors: Thoraval D , Asakawa J , Kodaira M , Chang C , Radany E , Kuick R , Lamb B , Richardson B , Neel J V , Glover T , Hanash S
Published: July 2002

We have implemented an approach for the detection of DNA alterations in cancer by means of computerized analysis of end-labeled genomic fragments, separated in two dimensions. Analysis of two-dimensional patterns of neuroblastoma tumors, prepared by first digesting DNA with the methylation-sensitive restriction enzyme Not I, yielded a multicopy fragment which was detected in some tumor patterns but not in normal controls. Cloning and sequencing of the fragment, isolated from two-dimensional gels, yielded a sequence with a strong homology to a subtelomeric sequence in chimpanzees and which was previously reported to be undetectable in humans. Fluorescence in situ hybridization indicated the occurrence of this sequence in normal tissue, for the most part in the satellite regions of acrocentric chromosomes. A product containing this sequence was obtained by telomere-anchored PCR using as a primer an oligonucleotide sequence from the cloned fragment. Our data suggest demethylation of cytosines at the cloned Not I site and in neighboring DNA in some tumors, compared with normal tissue, and suggest a greater similarity between human and chimpanzee subtelomeric sequences than was previously reported.
Cloning and characterization of a corepressor and potential component of the nuclear hormone receptor repression complex
Authors: Zamir Iris , Dawson Jessica , Lavinsky Robert M. , Glass Christopher K. , Rosenfeld Michael G. , Lazar Mitchell A.
Published: July 2002

Nuclear hormone receptors are potent repressors of transcription in the unliganded state. We describe here the cloning of a nuclear receptor corepressor that we call SUN-CoR (Small Unique Nuclear receptor CoRepressor), which shows no homology to previously described nuclear hormone receptor corepressors, N-CoR, or SMRT. SUN-CoR is a highly basic, 16-kDa nuclear protein that is expressed at high levels in adult tissues and is induced during adipocyte and myogenic differentiation. SUN-CoR potentiates transcriptional repression by thyroid hormone receptor and RevErb
in vivo
, represses transcription when fused to a heterologous DNA binding domain, and interacts with RevErb as well as with thyroid hormone receptor
in vitro
. SUN-CoR also interacts with N-CoR and SMRT
in vitro
and with endogenous N-CoR in cells. We conclude that SUN-CoR is a corepressor and may function as an additional component of the complex involved in transcriptional repression by unliganded and orphan nuclear hormone receptors.
Purification and characterization of the prothoracicotropic hormone of
Drosophila melanogaster
Authors: Kim Ae-Jung , Cha Guang-Ho , Kim Kyungjin , Gilbert Lawrence I. , Lee Chung Choo
Published: July 2002

The prothoracicotropic hormone (PTTH) of
Drosophila melanogaster
is a modulator of ecdysteroid (molting hormone) synthesis and was isolated and characterized from extracts of whole larvae (≈4 × 10
5
larvae). The purification protocol included delipidation, salt-extraction, heat treatment, conventional column chromatography, and HPLC, and yielded about 50 μg of pure hormone. Biological activity was followed using a ring gland
in vitro
assay in which ecdysteroidogenesis by control ring glands as measured by radioimmunoassay was compared with ring gland incubations containing active fractions. The molecular weight of the purified PTTH was 45 kDa and N-terminal amino acid sequence analysis indicated that those analyzed sequences displayed no significant homology with known peptides or peptide hormones, including PTTH from the silkmoth,
Bombyx mori
. Western blot analysis indicated that the native form of
Drosophila
PTTH was a single 66-kDa polypeptide with N-linked carbohydrate chains and intrachain disulfide bonds. The purified 45-kDa peptide is the deglycosylated form, a result of glycosidase activity present during preparation of the PTTH extract. The deglycosylated form shows heterogeneity, presumably as a result of varying degrees of deglycosylation at the N terminus.
Genetic determinants of susceptibility to excitotoxic cell death: Implications for gene targeting approaches
Authors: Schauwecker P. E. , Steward O.
Published: July 2002

Recent studies have sought to identify the genes involved in excitotoxic neurodegeneration. Here we report that certain strains of mice, including strains that are used for gene targeting studies, do not exhibit excitotoxic cell death after kainic acid seizures. Kainic acid produced excitotoxic cell death in the CA3 and CA1 subfields of the hippocampus in 129/SvEMS and FVB/N mice, in the same pattern as described in rats. C57BL/6 and BALB/c mice exhibited excitotoxic cell death only at very high doses of kainate, and then only in a very restricted area, although they exhibited comparable seizures. Hybrids of 129/SvEMS × C57BL/6 mice created using embryonic stem cells from 129/SvEMS mice also did not exhibit excitotoxic cell death. These results demonstrate that C57BL/6 and BALB/c strains carry gene(s) that convey protection from glutamate-induced excitotoxicity. This differential susceptibility to excitotoxicity represents a potential complication for gene targeting studies.
Localization of ADP-ribosylation factor domain protein 1 (ARD1) in lysosomes and Golgi apparatus
Authors: Vitale Nicolas , Horiba Koji , Ferrans Victor J. , Moss Joel , Vaughan Martha
Published: July 2002

ADP-ribosylation factor domain protein 1 (ARD1) is a member of the ADP ribosylation factor (ARF) family of guanine nucleotide-binding proteins that differs from other ARFs by the presence of a 46-kDa amino-terminal extension which acts as a GTPase-activating protein (GAP) for its ARF domain. Similar to ARF GAPs, the GAP domain of ARD1 contains a zinc finger motif and arginine residues that are critical for activity. It differs from other ARF GAPs in its covalent association with the GTP-binding domain and its specificity for the ARF domain of ARD1. ARFs are presumed to play a key role in the formation of intracellular transport vesicles and in their movement from one compartment to another. We report here that ARD1 overexpressed in cells, as a fusion or nonfusion protein, is localized in vesicular structures that are concentrated mainly in the perinuclear region, but are found also throughout the cytosol. Microscopic colocalization and subcellular fractionation studies showed that ARD1 was associated with the Golgi complex and lysosomal structures. ARD1 expressed as a green fluorescent fusion protein was initially associated with the Golgi network and subsequently localized to lysosomes. Lysosomal and Golgi membranes isolated from human liver by immunoaffinity contained native ARD1. Localization to these organelles, therefore, did not appear to be a result of overexpression. These observations suggest that the ARF-related protein ARD1 may play a role in the formation or function of lysosomes and in protein trafficking between Golgi and lysosomes.
Cloning and functional expression of a cDNA encoding a pheromone gland-specific acyl-CoA Δ
11
-desaturase of the cabbage looper moth,
Trichoplusia ni
Authors: Knipple Douglas C. , Rosenfield Claire-Lise , Miller Stuart J. , Liu Weitian , Tang Juliet , Ma Peter W. K. , Roelofs Wendell L.
Published: July 2002

Desaturation of coenzyme-A esters of saturated fatty acids is a common feature of sex pheromone biosynthetic pathways in the Lepidoptera. The enzymes that catalyze this step share several biochemical properties with the ubiquitous acyl-CoA Δ
9
-desaturases of animals and fungi, suggesting a common ancestral origin. Unlike metabolic acyl-CoA Δ
9
-desaturases, pheromone desaturases have evolved unusual regio- and stereoselective activities that contribute to the remarkable diversity of chemical structures used as pheromones in this large taxonomic group. In this report, we describe the isolation of a cDNA encoding a pheromone gland desaturase from the cabbage looper moth,
Trichoplusia ni
, a species in which all unsaturated pheromone products are produced via a Δ
11
Z-desaturation mechanism. The largest ORF of the ≈1,250-bp cDNA encodes a 349-aa apoprotein (PDesat-Tn Δ
11
Z) with a predicted molecular mass of 40,240 Da. Its hydrophobicity profile is similar overall to those of rat and yeast Δ
9
-desaturases, suggesting conserved transmembrane topology. A 182-aa core domain delimited by conserved histidine-rich motifs implicated in iron-binding and catalysis has 72 and 58% similarity (including conservative substitutions) to acyl-CoA Δ
9
Z-desaturases of rat and yeast, respectively. Northern blot analysis revealed an ≈1,250-nt PDesat-Tn Δ
11
Z mRNA that is consistent with the spatial and temporal distribution of Δ
11
-desaturase enzyme activity. Genetic transformation of a desaturase-deficient strain of the yeast
Saccharomyces cerevisiae
with an expression plasmid encoding PDesat-Tn Δ
11
Z resulted in complementation of the strain’s fatty acid auxotrophy and the production of Δ
11
Z-unsaturated fatty acids.
RAFT1 phosphorylation of the translational regulators p70 S6 kinase and 4E-BP1
Authors: Burnett Patrick E. , Barrow Roxanne K. , Cohen Noam A. , Snyder Solomon H. , Sabatini David M.
Published: July 2002

The complex of rapamycin with its intracellular receptor, FKBP12, interacts with RAFT1/FRAP/mTOR, the
in vivo
rapamycin-sensitive target and a member of the ataxia telangiectasia mutated (ATM)-related family of kinases that share homology with the catalytic domain of phosphatidylinositol 3-kinase. The function of RAFT1 in the rapamycin-sensitive pathway and its connection to downstream components of the pathway, such as p70 S6 kinase and 4E-BP1, are poorly understood. Here, we show that RAFT1 directly phosphorylates p70
S6k
, 4E-BP1, and 4E-BP2 and that serum stimulates RAFT1 kinase activity with kinetics similar to those of p70
S6k
and 4E-BP1 phosphorylation. RAFT1 phosphorylates p70
S6k
on Thr-389, a residue whose phosphorylation is rapamycin-sensitive
in vivo
and necessary for S6 kinase activity. RAFT1 phosphorylation of 4E-BP1 on Thr-36 and Thr-45 blocks its association with the cap-binding protein, eIF-4E,
in vitro
, and phosphorylation of Thr-45 seems to be the major regulator of the 4E-BP1–eIF-4E interaction
in vivo
. RAFT1 phosphorylates p70
S6k
much more effectively than 4E-BP1, and the phosphorylation sites on the two proteins show little homology. This raises the possibility that,
in vivo
, an unidentified kinase analogous to p70
S6k
is activated by RAFT1 phosphorylation and acts at the rapamycin-sensitive phosphorylation sites of 4E-BP1.
Expression cloning of
LDLB
, a gene essential for normal Golgi function and assembly of the ldlCp complex
Authors: Chatterton Jon E. , Hirsch David , Schwartz John J. , Bickel Perry E. , Rosenberg Robert D. , Lodish Harvey F. , Krieger Monty
Published: July 2002

The Chinese hamster ovary (CHO) cell mutants ldlC and ldlB, which exhibit almost identical phenotypes, define two genes required for multiple steps in the normal medial and trans Golgi-associated processing of glycoconjugates. The
LDLC
gene encodes ldlCp, an ≈80-kDa protein, which in wild-type, but not ldlB, cells associates reversibly with the cytoplasmic surface of the Golgi apparatus. Here, we have used a retrovirus-based expression cloning system to clone a murine cDNA,
LDLB
, that corrects the pleiotropic mutant phenotypes of ldlB cells. The corresponding mRNA was not detected in ldlB mutants.
LDLB
encodes an ≈110-kDa protein, ldlBp, which lacks homology to known proteins and contains no common structural motifs. Database searches identified short segments of homology to sequences from
Drosophila melanogaster
,
Arabidopsis thaliana
, and
Caenorhabditis elegans
, and the essentially full-length homologous human sequence (82% identity); however, as was the case for ldlCp, no homologue was identified in
Saccharomyces cerevisiae
. We have found that in wild-type cell cytosols, ldlCp is a component of an ≈950-kDa “ldlCp complex,” which is smaller, ≈700 kDa, in ldlB cytosols. Normal assembly of this complex is ldlBp-dependent and may be required for Golgi association of ldlCp and for the normal activities of multiple luminal Golgi processes.
Different
TBX5
interactions in heart and limb defined by Holt–Oram syndrome mutations
Authors: Basson Craig T. , Huang Taosheng , Lin Robert C. , Bachinsky David R. , Weremowicz Stanislawa , Vaglio Alicia , Bruzzone Rina , Quadrelli Roberto , Lerone Margherita , Romeo Giovanni , Silengo Margherita , Pereira Alexandre , Krieger Jose , Mesquita Sonia F. , Kamisago Mitsuhiro , Morton Cynthia C. , Pierpont Mary Ella M. , Müller Chistoph W. , Seidman J. G. , Seidman Christine E.
Published: July 2002

To better understand the role of TBX5, a T-box containing transcription factor in forelimb and heart development, we have studied the clinical features of Holt–Oram syndrome caused by 10 different
TBX5
mutations. Defects predicted to create null alleles caused substantial abnormalities both in limb and heart. In contrast, missense mutations produced distinct phenotypes: Gly80Arg caused significant cardiac malformations but only minor skeletal abnormalities; and Arg237Gln and Arg237Trp caused extensive upper limb malformations but less significant cardiac abnormalities. Amino acids altered by missense mutations were located on the three-dimensional structure of a related T-box transcription factor,
Xbra
, bound to DNA. Residue 80 is highly conserved within T-box sequences that interact with the major groove of target DNA; residue 237 is located in the T-box domain that selectively binds to the minor groove of DNA. These structural data, taken together with the predominant cardiac or skeletal phenotype produced by each missense mutation, suggest that organ-specific gene activation by TBX5 is predicated on biophysical interactions with different target DNA sequences.
Negative regulation of
atonal
in proneural cluster formation of
Drosophila
R8 photoreceptors
Authors: Chen Chien-Kuo , Chien Cheng-Ting
Published: July 2002

atonal
(
ato
) encodes a basic helix–loop–helix protein and is required for the specification of R8 photoreceptor cells in
Drosophila
. In the eye imaginal discs, expression of Ato protein is initially in a dorsoventral stripe of cells anterior to the morphogenetic furrow (MF). In the MF, this stripe expression is resolved into regularly spaced clusters of Ato-positive cells, the proneural clusters, which are intervened with Ato-negative cells. Another basic helix–loop–helix protein, Daughterless (Da), dimerizes with Ato and is expressed at an enhanced level in Ato-expressing cells. Here we show that during the late stages of proneural clusters, the mitogen-activated protein kinase (MAPK) is activated in proneural clusters. Normal
ato
or
da
activity is required for maintenance of MAPK activation. Furthermore, in
ato
or
da
mutants, Ato expression is expanded to all cells in the MF, suggesting that
ato
and
da
are required for Ato repression in cells between proneural clusters. By changing the MAPK activity in proneural clusters, we show that MAPK activation mediates Ato repression nonautonomously. Consistently, hyperactivation of the MAPK in a stripe of cells posterior to or overlapping the Ato stripe eliminates the formation of proneural clusters. Taken together, these results suggest that a negative regulatory loop involving MAPK activation and Ato repression is required for the generation of evenly spaced proneural clusters.
A common muscarinic pathway for diapause recovery in the distantly related nematode species
Caenorhabditis elegans
and
Ancylostoma caninum
Authors: Tissenbaum Heidi A. , Hawdon John , Perregaux Melissa , Hotez Peter , Guarente Leonard , Ruvkun Gary
Published: July 2002

Converging TGF-β and insulin-like neuroendocrine signaling pathways regulate whether
Caenorhabditis elegans
develops reproductively or arrests at the dauer larval stage. We examined whether neurotransmitters act in the dauer entry or recovery pathways. Muscarinic agonists promote recovery from dauer arrest induced by pheromone as well as by mutations in the TGF-β pathway. Dauer recovery in these animals is inhibited by the muscarinic antagonist atropine. Muscarinic agonists do not induce dauer recovery of either
daf-2
or
age-1
mutant animals, which have defects in the insulin-like signaling pathway. These data suggest that a metabotropic acetylcholine signaling pathway activates an insulin-like signal during
C. elegans
dauer recovery. Analogous and perhaps homologous cholinergic regulation of mammalian insulin release by the autonomic nervous system has been noted. In the parasitic nematode
Ancylostoma caninum
, the dauer larval stage is the infective stage, and recovery to the reproductive stage normally is induced by host factors. Muscarinic agonists also induce and atropine potently inhibits
in vitro
recovery of
A. caninum
dauer arrest. We suggest that host or parasite insulin-like signals may regulate recovery of
A. caninum
and could be potential targets for antihelminthic drugs.
Statistical methods for characterizing similarities and differences between semantic structures
Authors: Romney A. Kimball , Moore Carmella C. , Batchelder William H. , Hsia Ti-Lien
Published: July 2002

This paper describes a variety of statistical methods for obtaining precise quantitative estimates of the similarities and differences in the structures of semantic domains in different languages. The methods include comparing mean correlations within and between groups, principal components analysis of interspeaker correlations, and analysis of variance of speaker by question data. Methods for graphical displays of the results are also presented. The methods give convergent results that are mutually supportive and equivalent under suitable interpretation. The methods are illustrated on the semantic domain of emotion terms in a comparison of the semantic structures of native English and native Japanese speaking subjects. We suggest that, in comparative studies concerning the extent to which semantic structures are universally shared or culture-specific, both similarities and differences should be measured and compared rather than placing total emphasis on one or the other polar position.
Finance organizations, decisions and emotions
Authors: Pixley Jocelyn
Published: July 2002

Analyses of global financial markets are dominated by atomized models of decision‐making and behavioural psychology (‘exuberance’ or ‘panic’). In contrast, this paper argues that overwhelmingly, finance organizations rather than ‘individuals’ make decisions, and routinely use emotions in formulating expectations. Keynes introduced emotion (business confidence and animal spirits) but in economics, emotion remains individualistic and irrational. Luhmann's system theory lies at the other extreme, where emotions like trust and confidence are central variables, functional in the reduction of complexity in sub‐systems like the economy. The gap between irrational emotions aggregated to ‘herd’ behaviour in economics, and ‘system trust’ applied to finance and money as a ‘medium of communication’ in sociology, remains largely unfilled. This paper argues that while organizations cannot be said to ‘think’ or ‘feel’, they are rational and emotional, because impersonal trust, confidence and their contrary emotions are unavoidable in decision‐making due to fundamental uncertainty. These future‐oriented emotions are prevalent within and between organizations in the financial sector, primarily in generating expectations. The dynamic of corporate activities of tense and ruthless struggle is a more plausible level of analysis than either financial ‘manias’ in aggregate or ‘system trust’.
Alternatives Models in Carcinogenicity Testing—A European Perspective
Authors: Van Der Laan Jan Willem , Silva Lima Beatriz , Snodin David
Published: July 2002

Transgenic mouse strains offer the prospect of significant benefits in the in vivo assessment of carcinogenic potential. The European Regulatory Authorities have been supportive of their inclusion as one of the second-test options in the International Conference on Harmonization of Technical Requirements for the Registration of Pharmaceuticals for Human use (ICH). However, there is a concern regarding premature systematic use of these models. At present, the information from the International Life Sciences Institute (ILSI) project suggests that the transgenic models under study are similarly sensitive to genotoxic pharmaceuticals. There are apparently some false negatives and false positives. For regulatory purposes, it is not yet possible to differentiate the models with respect to hazard identification and risk assessment. The evaluation of the models has reached an interesting but, at certain points, equivocal stage. Based on the weight of evidence gathered thus far, regulatory authorities cannot neglect the outcome of such studies but need to be cautious in their interpretation of data from such models, and the application in risk assessment procedures.
Effects of granulocyte‐macrophage colony‐stimulating factor and cyclic AMP interaction on human neutrophil apoptosis
Authors: Tortorella Cosimo , Piazzolla Giuseppina , Spaccavento Felice , Antonaci Salvatore
Published: July 2002

The current study was undertaken to evaluate the effects of granulocyte‐macrophage colony‐stimulating factor (GM‐CSF) and cyclic AMP (cAMP) signaling interaction on human neutrophil apoptosis, either occurring spontaneously or induced by Fas antigen activation. Results show that GM‐CSF, dibutyryl cAMP (a cAMP analog) and forskolin (an adenylate cyclase activator) are all able to suppress spontaneous neutrophil cell death. Of note however, when GM‐CSF is used in combination with cAMP‐elevating agents, an additive effect on neutrophil survival is observed with dibutyryl cAMP only, whereas supplementation of cell cultures with GM‐CSF and forskolin results in a progressive reduction of antiapoptotic effects exerted by the single compounds. Moreover, although dibutyryl cAMP and forskolin do not affect Fas‐triggered apoptotic events, they are still able to modulate the GM‐CSF capacity to prolong neutrophil survival following anti‐Fas IgM cell challenge, with effects similar to those respectively exerted on spontaneous neutrophil apoptosis. The data indicate that GM‐CSF m ay negatively modulate the cAMP‐mediated antiapoptotic pathway in human neutrophils, likely via the inhibition of adenylate cyclase activity. This would prevent an abnormal neutrophil survival as a result of cAMP signaling stimulation, which provides a novel insight into the role of GM‐CSF as a physiological regulator of myeloid cell turnover.
Acidosis activates complement system in vitro
Authors: Emeis Michael , Sonntag Josef , Willam Carsten , Strauss Evelyn , Walka Matthias M. , Obladen Michael
Published: July 2002

We investigated the in vitro effect of different form s of acidosis (pH 7.0) on the formation of anaphylatoxins C3a and C5a. Metabolic acidosis due to addition of hydrochloric acid (10 μ mol/ml blood) or lactic acid (5.5 μ mol/ml) to heparin blood (N = 12) caused significant activation of C3a and C5a compared to control (both p = 0.002). Respiratory acidosis activated C3a (p = 0.007) and C5a (p = 0.003) compared to normocapnic controls. Making blood samples with lactic acidosis hypocapnic resulted in a median pH of 7.37. In this respiratory compensated metabolic acidosis, C3a and C5a were not increased. These experiments show that acidosis itself and not lactate trigger for activation of complement components C3 and C5.
Glycoconjugate secretion in human airways in vitro: effects of epithelium removal
Authors: Sossé-Alaoui H. , Labat C. , Gorenne I. , de Montpreville V. Thomas , Bara J. , Brink C.
Published: July 2002

The aim of this study was to examine glycoconjugate secretion in human airways with and without an epithelium. Glycoconjugate release in supernatants derived from human airways in vitro was determined using an ELISA assay with an anti‐human mucin monoclonal antibody (MAb 3D3). This monoclonal antibody reacted strongly with Leb antigen but also recognized in vitro Lea and Ley determinents. In 11 of the 34 different lung samples (32%) studied the glycoconjugate levels were below the threshhold of detection for this assay. The mean basal secretion of glycoconjugates in human airways in vitro was 100 ±28 μg/g tissue (Period I; n = 23 different lung samples). The amount of glycoconjugate measured in the medium derived from human isolated bronchial ring preparations did not change under control conditions during the course of the experimental procedure (Period I; 128 ± 46 μg/g tissue and Period II; 159 ± 48 μg/g tissue; n = 13 paired lung samples). In the supernatants of airway preparations with an intact epithelium the amount of glycoconjugates detected was 90 ± 38 μg/g tissue (Period I; n = 12 different lung samples) and removal of the epithelium did not alter this basal glycoconjugate release (94 ± 60 μg/g tissue: Period I, n = 8 different lung samples). The absence of the epithelial layer was confirmed by histological evaluation. Methacholine (100 μM) induced a 10‐ and four‐fold increase in glycoconjugate release from airways with and without an epithelium, respectively. In contrast, in preparations with an epithelium, LTD4 (10 μM) and anti‐IgE (dilution: 1/1000) did not cause an increase of glycoconjugate release. The methacholine difference between airways with and without an epithelium was not significantly different (P > 0.10). However, a treatment with atropine (100 μM) prevented the increase of glycoconjugate release in preparations with an epithelium. These data derived from a limited number of experiments suggest that the epithelium may not regulate the basal or stimulated release of glycoconjugates from isolated human airways.
Reduced Airway Hyperresponsiveness by Phosphodiesterase 3 and 4 Inhibitors in Guinea‐Pigs
Authors: Germain Nöella , Boichot Elisabeth , Planquois Jean-Michel , Lagente Vincent
Published: July 2002

The aim of the present study was to compare the effects of selective phosphodiesterase (PDE) 3, 4 and 5 inhibitors on antigen‐induced airway hyperresponsiveness in sensitized guinea‐pigs. When the sensitized guinea‐pigs were orally pre‐treated with the selective PDE4 inhibitor, Ro 20‐1724 (30 mg/kg), and studied 48 h after OA, a significant reduction (p < 0.01) of the leftward shift of the dose‐response curve to ACh was noted, whereas it was ineffective at the lower dose (10 mg/kg). Administration of the selective PDE3 inhibitor, milrinone (30 mg/kg) also elicited a significant reduction (p < 0.01) of the airway hyperresponsiveness, whereas the PDE5 inhibitor zaprinast (30 mg/kg) was ineffective. These results show that both PDE3 and PDE4 inhibitors are able to inhibit the antigen‐induced airway hyperresponsiveness in sensitized guinea‐pigs and support the potential utility of selective PDE inhibitors in the treatment of asthma.
Osteogenic Sarcoma of the Maxilla: Neutron Therapy for UnresectableDisease
Authors: Smoron Geoffrey L. , Lennox Arlene J. , Mcgee James L.
Published: July 2002

Purpose. To present a case study involving the use of fast neutron
therapy to treat an extensive unresectable osteogenic sarcoma arising from
the left maxilla.

Patient. A 14‐year‐old male presented with a massive tumor producing
severe distortion of his facial structures. He had already received six courses of
chemotherapy, which had reduced his pain, but had not measurably reduced the tumor.

Methods. The patient was treated with 66 MeV fast neutrons to a dose
of 20.4 Gy in 13 fractions over 35 days.

Results. CT assessments indicate gradually increasing calcification
and noticeable reduction of soft‐tissue disease in the frontal sinus, orbit and maxillary
antrum.There has been some recontouring of the facial structures.The boy conducts an
active life, has no pain, and feels well. He was 17 years old at the last follow‐up.

Discussion. Fast neutrons have a greater biological effectiveness
than conventional photon beams. Their use has been associated with improved chance
for local control of unresectable disease.This case illustrates their effectiveness in
controlling an unusual and aggressive osteogenic sarcoma of the facial bone and sinuses.
The Role of the Cooh Terminus of Sec2p in the Transport of Post-Golgi Vesicles
Authors: Elkind N. Barry , Walch-Solimena Christiane , Novick Peter J.
Published: July 2002

Sec2p is required for the polarized transport of secretory vesicles in S. cerevisiae. The Sec2p NH2 terminus encodes an exchange factor for the Rab protein Sec4p. Sec2p associates with vesicles and in Sec2p COOH-terminal mutants Sec4p and vesicles no longer accumulate at bud tips. Thus, the Sec2p COOH terminus functions in targeting vesicles, however, the mechanism of function is unknown. We found comparable exchange activity for truncated and full-length Sec2 proteins, implying that the COOH terminus does not alter the exchange rate. Full-length Sec2-GFP, similar to Sec4p, concentrates at bud tips. A COOH-terminal 58–amino acid domain is necessary but not sufficient for localization. Sec2p localization depends on actin, Myo2p and Sec1p, Sec6p, and Sec9p function. Full-length, but not COOH-terminally truncated Sec2 proteins are enriched on membranes. Membrane association of full-length Sec2p is reduced in sec6-4 and sec9-4 backgrounds at 37°C but unaffected at 25°C. Taken together, these data correlate loss of localization of Sec2 proteins with reduced membrane association. In addition, Sec2p membrane attachment is substantially Sec4p independent, supporting the notion that Sec2p interacts with membranes via an unidentified Sec2p receptor, which would increase the accessibility of Sec2p exchange activity for Sec4p.
Exclusion of Golgi Residents from Transport Vesicles Budding from Golgi Cisternae in Intact Cells
Authors: Orci Lelio , Amherdt Mylène , Ravazzola Mariella , Perrelet Alain , Rothman James E.
Published: July 2002

A central feature of cisternal progression/maturation models for anterograde transport across the Golgi stack is the requirement that the entire population of steady-state residents of this organelle be continuously transported backward to earlier cisternae to avoid loss of these residents as the membrane of the oldest (trans-most) cisterna departs the stack. For this to occur, resident proteins must be packaged into retrograde-directed transport vesicles, and to occur at the rate of anterograde transport, resident proteins must be present in vesicles at a higher concentration than in cisternal membranes. We have tested this prediction by localizing two steady-state residents of medial Golgi cisternae (mannosidase II and N-acetylglucosaminyl transferase I) at the electron microscopic level in intact cells. In both cases, these abundant cisternal constituents were strongly excluded from buds and vesicles. This result suggests that cisternal progression takes place substantially more slowly than most protein transport and therefore is unlikely to be the predominant mechanism of anterograde movement.
Germinal Center Founder Cells Display Propensity for Apoptosis before Onset of Somatic Mutation
Authors: Lebecque Serge , de Bouteiller Odette , Arpin Christophe , Banchereau Jacques , Liu Yong-Jun
Published: July 2002

B lymphocytes undergo affinity maturation of their antigen receptors within germinal centers. These anatomical structures develop in secondary lymphoid organs from the clonal expansion of a few antigen-specific founder B cells, whose isolation and characterization are reported here. Human germinal center founder cells express the naive B cell markers surface IgM and IgD as well as the germinal center B cell markers CD10 and CD38. They express low levels of Bcl-2, high levels of Fas, and undergo rapid apoptosis in culture. The smaller nonproliferating sIgM+IgD+CD38+ B cells displayed a lower level of somatic mutation in their immunoglobulin variable region genes compared with the large proliferating ones. Unmutated sIgM+IgD+CD38+ tonsillar B cells may thus represent germinal center founder cells in which the program for apoptotic cell death is triggered before the onset of somatic mutation, allowing the selection of the germline antibody repertoire at an early stage.
Enhanced Growth of Primary Tumors in Cancer-Prone Mice after Immunization against the Mutant Region of an Inherited Oncoprotein
Authors: Siegel Christopher T. , Schreiber Karin , Meredith Stephen C. , Beck-Engeser Gabriele B. , Lancki David W. , Lazarski Christopher A. , Fu Yang-Xin , Rowley Donald A. , Schreiber Hans
Published: July 2002

One major objective of tumor immunologists is to prevent cancer development in individuals at high risk. (TG.AC × C57BL/6)F1 mice serve as a model for testing the feasibility of this objective. The mice carry in the germline a mutant ras oncogene that has an arginine at codon 12 instead of glycine present in the wild-type, and after physical (wounding) or chemical promotion, these mice have a high probability for developing papillomas that progress to cancer. Furthermore, F1 mice immunized with Arg12 mutant ras peptide in complete Freund's adjuvant (CFA) develop T cells within 10 d that proliferate in vitro on stimulation with the Arg12 mutant ras peptide. Within 14 d, these mice have delayed-type hypersensitivity to the peptide. Immunization with CFA alone or with a different Arg12 mutant ras peptide in CFA induced neither response. To determine the effect of immunization on development of tumors, mice immunized 3 wk earlier were painted on the back with phorbol 12-myristate 13-acetate every 3 d for 8 wk. The time of appearance and the number of papillomas were about the same in immunized and control mice, but the tumors grew faster and became much larger in the mice immunized with the Arg12 mutant ras peptide. Thus, the immunization failed to protect against growth of papillomas. The peptide-induced CD4+ T cells preferentially recognized the peptide but not the native mutant ras protein. On the other hand, mice immunized with Arg12 mutant ras peptide and bearing papillomas had serum antibodies that did bind native mutant ras protein. Together, these studies indicate that active immunization of cancer-prone individuals may result in immune responses that fail to eradicate mutant oncogene–expressing tumor cells, but rather induce a remarkable enhancement of tumor growth.
Increased Severity of Local and Systemic Anaphylactic Reactions in Gp49b1-Deficient Mice
Authors: Daheshia Massoud , Friend Daniel S. , Grusby Michael J. , Austen K. Frank , Katz Howard R.
Published: July 2002

gp49B1 is an immunoglobulin (Ig) superfamily member that inhibits FcεRI-induced mast cell activation when the two receptors are coligated with antibodies in vitro. The critical question of in vivo function of gp49B1 is now addressed in gene-disrupted mice. gp49B1-deficient mice exhibited a significantly increased sensitivity to IgE-dependent passive cutaneous anaphylaxis as assessed by greater tissue swelling and mast cell degranulation in situ. Importantly, by the same criteria, the absence of gp49B1 also resulted in a lower threshold for antigen challenge in active cutaneous anaphylaxis, in which the antigen-specific antibody levels were comparable in gp49B1-deficient and sufficient mice. Moreover, the absence of gp49B1 resulted in a significantly greater and faster death rate in active systemic anaphylaxis. These results indicate that gp49B1 innately dampens adaptive immediate hypersensitivity responses by suppressing mast cell activation in vivo. In addition, this study provides a new concept and target for regulation of allergic disease susceptibility and severity.
Genes, lineages and the neural crest: a speculative review
Authors: Anderson David J.
Published: July 2002

Sensory and sympathetic neurons are generated from the trunk neural crest. The prevailing view has been that these two classes of neurons are derived from a common neural crest–derived progenitor that chooses between neuronal fates only after migrating to sites of peripheral ganglion formation. Here I reconsider this view in the light of new molecular and genetic data on the differentiation of sensory and autonomic neurons. These data raise several paradoxes when taken in the context of classical studies of the timing and spatial patterning of sensory and autonomic ganglion formation. These paradoxes can be most easily resolved by assuming that the restriction of neural crest cells to either sensory or autonomic lineages occurs at a very early stage, either before and/or shortly after they exit the neural tube.
A method for simultaneous correction of spectrum hardening artifacts in CT images containing both bone and iodine
Authors: Joseph Peter M. , Ruth Christopher
Published: July 2002

A method is described capable of correcting artifacts in x‐ray computer tomography (CT) images due to beam hardening in an arbitrary number of substances. The method works with reconstructed image data and does not require the original raw data. It is necessary to have an estimate of the spectrum of the incident x‐ray beam. The method is similar to previously described iterative methods that correct artifacts induced by bones. Our implementation was designed to correct for hardening in both bone and iodine contrast agent. It is necessary to identify those regions of the image which contain bone and iodine. A central concept is that of effective density, which is the ratio of CT number of the substance to that of water. It is necessary to establish by a preliminary experiment the relationship between CT number and mass density of iodine or bone. From these data one estimates path integrals through soft tissue (water equivalent), bone, and iodine using a reprojection algorithm applied to the given image. Given this input, a key equation is solved numerically which provides a correction term to be subtracted from the reprojected data. This can be shown to eliminate the nonlinear terms in the projections due to beam hardening, assuming that the original density estimates were correct. In principle, the method can be repeated iteratively to improve the accuracy. However, in our experience using an image of a phantom containing iothalamate meglumine and scanned using the Siemens Evolution electron beam tomography scanner, the quality of the corrected image was excellent and no further iteration is needed for the phantoms studied. More research is needed to implement the method on clinical scans.
Phase singularities in beams
Authors: Brand G. F.
Published: July 2002

Beams of electromagnetic radiation with phase singularities can transport angular momentum and exert torques on objects. In this paper we discuss the generation of such beams and present a simple analysis of the phenomenon. These beams and their effects have been studied at optical and at millimeter wavelengths. We describe a particularly efficient way of generating these beams at millimeter wavelengths employing a specially configured blazed grating.
Frequency modulation detection interference produced by asynchronous and nonsimultaneous interferers
Authors: Gockel Hedwig , Carlyon Robert P.
Published: July 2002

The effect of asynchronous and nonsimultaneous interferers on detection of sinusoidal frequency modulation (FM) was compared with the effect of a synchronous interferer. In a two-interval, two-alternative forced-choice (2I-2AFC) adaptive procedure, listeners had to detect FM with a modulation frequency of 15 Hz, imposed on a 1-kHz sinusoidal carrier (the target). The 200-ms target was presented either alone (baseline condition), or with an interferer whose timing relative to the target was varied. The interferer was a 2.3-kHz sinusoidal carrier which was also frequency modulated at a rate of 15 Hz. Experiment one showed that thresholds for detection of FM increased significantly, both with a synchronous FM interferer, and also with asynchronous interferers (starting 200 ms before and stopping 200 ms after the target). Moreover, “gapped” interferers that were turned off during presentation of the target (presented for 200 ms before and for 200 ms after the target but not simultaneously) produced the same significant increase in thresholds as an asynchronous interferer that was not interrupted. In contrast, thresholds were not affected by the presence of a gapped unmodulated sinusoidal interferer. Experiment two showed that increasing the duration of the silent gap (centered on presentation of the target) between FM interferers from 200 to 600 ms did not abolish the interference. Thus nonsimultaneous FM interferers produced frequency modulation detection interference (FMDI) even when the silent gap between the interferers and target clearly led to the interferers and target being perceived as separate auditory objects. A possible explanation for the findings is the existence of an asymmetry in perception of steady and modulated sounds, as recently proposed by Cusack and Carlyon [Br. J. Audiol. 34.2, 112 (2000)]. Alternative explanations in terms of ringing in a hypothetical modulation filter bank and adaptation seem unlikely.
Application of the Foldy–Wouthuysen transformation to the reduced wave equation in range-dependent environments
Authors: Wurmser Daniel , Orris Gregory J. , Dashen Roger
Published: July 2002

The Foldy–Wouthuysen transformation can be used to reduce the relativistic Klein–Gordon equation to the nonrelativistic Schrödinger equation. This technique is modified and applied to the problem of wave propagation through media with a range-dependent index of refraction. The forward and backward propagating components of the field are decoupled order-by-order to produce a perturbative expansion of the range-dependent parabolic equation. The result includes energy-conserving correction terms that can be associated with a rapid fluctuation of energy between forward and backward propagating solutions of the Helmholtz equation. The approach selects out physical processes which accumulate over the entire range of propagation, distinguishing them from effects which depend solely on the initial and final values of the index of refraction and its derivatives. It is also shown that the corresponding backscatter mechanism is fundamentally nonperturbative, so that the parabolic equation technique as applied to the problem of propagation through range-dependent media generates an asymptotic expansion of the exact solution. This procedure has been applied to long-distance low-frequency propagation through a sound channel with internal waves. For this application, the expansion parameters are typically very small, so the propagation distances must be very large for the effect to be detectable.
The pitch of short-duration fundamental frequency glissandos
Authors: d’Alessandro Christophe , Rosset Sophie , Rossi Jean-Pierre
Published: July 2002

Pitch perception for short-duration fundamental frequency (F0) glissandos was studied. In the first part, new measurements using the method of adjustment are reported. Stimuli were F0 glissandos centered at 220 Hz. The parameters under study were: F0 glissando extents (0, 0.8, 1.5, 3, 6, and 12 semitones, i.e., 0, 10.17, 18.74, 38.17, 76.63, and 155.56 Hz), F0 glissando durations (50, 100, 200, and 300 ms), F0 glissando directions (rising or falling), and the extremity of F0 glissandos matched (beginning or end). In the second part, the main results are discussed: (1) perception seems to correspond to an average of the frequencies present in the vicinity of the extremity matched; (2) the higher extremities of the glissando seem more important; (3) adjustments at the end are closer to the extremities than adjustments at the beginning. In the third part, numerical models accounting for the experimental data are proposed: a time-average model and a weighted time-average model. Optimal parameters for these models are derived. The weighted time-average model achieves a 94% accurate prediction rate for the experimental data. The numerical model is successful in predicting the pitch of short-duration F0 glissandos.
Ultrasonic in-situ determination of the regression rate of the melting interface in burning metal rods
Authors: Veidt Martin , Steinberg Theodore A.
Published: July 2002

Results of tests in which metallic rods are burned in oxygen enriched atmospheres often include the determination of the regression rate of the melting interface for the burning test specimen. This regression rate is used as an indication of a metallic material’s relative flammability and its general ability to sustain burning under the test conditions. This paper reports on the development and first application of an ultrasonic measurement system that enables in situ measurement of the regression rate of the melting interface in burning metal rods. All other methods currently used for determining this parameter are based on posttest, visual interrogation, which is costly and often inaccurate. The transducer and associated equipment used to drive and record the transducer’s output signal are described and typical results for iron rods burning in pure oxygen at different gauge pressures are given along with a comparison of these results with regression rates obtained from visual interrogation. The excellent sensitivity, accuracy and reliability of the new ultrasonic transducer are demonstrated, thus indicating the transducer’s great potential.
Response magnitude and timing of auditory response initiation in the inferior colliculus of the awake chinchilla
Authors: Phillips Dennis P. , Burkard Robert
Published: July 2002

Recent single-unit studies in anesthetized cats have revealed that the latency and strength of transient responses to tone burst stimuli are determined largely by stimulus events in the first few ms of the signal. The present study sought to extend these findings by studying the inferior colliculus potential (ICP) in unanesthetized chinchillas. The ICP magnitude and latency were studied as a function of the plateau amplitude and rise time of noise burst stimuli. ICP amplitude increased with stimulus amplitude and decreased with stimulus rise time. ICP latency decreased with stimulus amplitude and increased with stimulus rise time. The absolute values of the ICP latencies confirmed that it is only the first few ms of the stimulus which determine the timing of response initiation, and therefore, that it is not the plateau level of the stimulus that directly determines the latent period. These data constitute a direct link between earlier single-unit studies in anesthetized animals and brainstem-evoked potential data in animals and man.
Measurements of lung vibration in response to low-frequency sound
Authors: McAleavey Stephen A. , Raeman Carol H. , Parker Kevin J. , Dalecki Diane
Published: July 2002

The amplitude of vibration of lung in response to low-frequency (100–500 Hz) sound was measured in mice and rats in vivo. Low-frequency sound fields were generated in an inertial water column driven at its base with an electromagnetic transducer. Estimates of vibration amplitude of the lung were obtained by calculating the variations in the round-trip delay of pulsed wideband ultrasound bursts. The relative time delays were calculated by determining the maximum of the cross-correlation of the first echo with subsequent echoes. The ultrasound bursts were emitted at a rate of 1–5 kHz, allowing ten displacement estimates to be calculated per cycle of lung oscillation. The mean resonance frequencies obtained through measurements of vibration amplitude were 330 Hz for mice and 189 Hz for rats. The maximum observed displacements were on the order of 0.1 mm. The resonance observed through measurements of displacement amplitude was equivalent to that obtained through acoustic scattering measurements and consistent with observations of lung hemorrhage.
An Experimental Program for Finite Linear Viscoelasticity
Authors: DeHoff Paul H. , Lianis George , Goldberg William
Published: July 2002

Results of uniaxial stress relaxation experiments under finite strain are presented. Relaxation functions appearing in an approximate nonlinear constitutive equation are evaluated for a polyurethane material. The accuracy of these functions is checked by a strip biaxial test in which predicted response is compared with measured response. In addition, based on relaxation tests of ethylene propylene, a second approximate constitutive equation is proposed.