bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Co‐Operation Between Eotaxin and Substance‐P in Inducing Eosinophil‐Derived Neurotoxin Release
Authors: El-Shazly Amr , Ishikawa Takeru
Published: July 2002

Eosinophils, chemokines, and neuropeptides are thought to play effector roles in the pathogenesis of allergic diseases such as rhinitis. Eotaxin is a novel C‐C chemokine with a potent and relatively specific eosinophil chemoattractant activity that binds selectively to CCR3 receptor, however, its activity in inducing eosinophil granules proteins release is poorly characterized. This study was performed to determine whether eotaxin primes eosinophil exocytosis and whether this co‐operates with the sensory neuroimmune‐axis. In the present communication, we show that 10 ng/ml eotaxin primed normal human eosinophil for exaggerated eosonophil‐derived neurotoxin (EDN) release stimulated by 10-8 M Substance‐P (SP). This novel priming was blocked by; 7B11 and Herbimycin A (HA), the CCR3 antagonist and the tyrosine kinase inhibitor, respectively. SDS‐Page studies showed significant tyrosine phosphorylation of several protein residues induced by 10-8 M SP only after priming with 10 ng/ml eotaxin. These results demonstrate a novel co‐operation between eotaxin and SP in inducing eosinophil cytotoxicity, which at least in part involves tyrosine kinases pathway(s).
Fatty acid ethyl esters: nonoxidative metabolites of ethanol
Authors: LAPOSATA MICHAEL
Published: July 2002

The story of fatty acid ethyl (FAEE) encompasses nearly 40 years of research. For more than half of this time, the investigation was limited to documenting the presence of ethyl ester synthesis in different cells and tissues. In the last three years, increasing evidence has emerged that FAEE contribute to ethanol‐induced organ damage, with a variety of different mechanisms proposed for mediation of this toxic effect. In addition, multiple enzymatic activities associated with FAEE formation have been described. Independent of their role in mediating cell injury, it has very recently been shown that FAEE are useful short‐term and long‐term serum markers of ethanol intake, given their appearance in the blood rapidly after ethanol ingestion and their presence when ethanol is no longer detectable.
Reliable Establishment of Human Sarcoma Xenografts in the Nude Rat
Authors: Tinkey Peggy T. , Milas Mira , Pollock Raphael E.
Published: July 2002

Purpose. The ability to establish consistent human tumor xenografts in
experimental animals is a crucial part of preclinical investigations.The goal of this study was
to develop a method of establishing a human tumor xenograft in the leg of a nude rat for
evaluation of new surgical and molecular methods of treatments of human extremity
sarcoma.

Methods and results. Initial attempts to produce sarcoma nodules by
subcutaneous injection of a human leiomyosarcoma tumor cell suspension (SKLMS‐1)
resulted in tumor nodule formation in only four of 10 sites (40%).The xenograft method
was modified to include younger nude rats of a different source and substrain
(HSD:rnu/rnu, 5–9 weeks old), treated with 500 cGy whole‐body irradiation, and the
transplantation of tumor cells or small tumor fragments which had been embedded
in Matrigel.These changes improved the tumor take rate per site to 52/52 (100%).Tumor
nodules demonstrated rapid and progressive growth and histological features consistent
with the original human sarcoma.

Discussion. Successful human leiomyosarcoma establishment in
these nude rats permits the investigation of sarcoma biology and treatment with surgical
procedures for which a mouse model would be inadequate. In this study we identified
modifications in technique which enhanced the xenografting of a leiomyosarcoma cell
line in nude rats; these techniques may increase tumor take rates for other tumor types
as well.
Malignant Hemangiopericytoma Arising in Neurofibromatosis: A CaseReport with Histological, Immunohistochemical and UltrastructuralStudies
Authors: Wang Jun , Vargas Hernan , Gaal Karl , Wang Xia , Peng Shi-Kaung
Published: July 2002

Subject. A 27‐year‐old Hispanic male with clinical manifestation of
neurofibromatosis type 1 developed chronic constipation and urination difficulty along with
recently increased abdominal bloating and anorexia. He also noted 40 lbs weight loss
over period of 1 year. Physical and radiographic examinations revealed a large mass in the
right pelvic fossa.

Results. The surgically removed tumor was demonstrated,
histologically, immunohistochemically, and ultrastructurally, to be a malignant
hemangiopericytoma.

Discussion.Although non‐neurogenic tumors associated with neurofibromatosis
have been reported in these patients, only one hemangiopericytoma case has been found in the English literature. We report here another case of this rare malignant
hemangiopericytoma in a patient with neurofibromatosis.
Selenium, the Element of the Moon, in Life on Earth
Authors: Flohé Leopold , Andreesen Jan R. , Brigelius‐Flohé Regina , Maiorino Matilde , Ursini Fulvio
Published: July 2002

The present status of selenium biochemistry is reviewed with particular emphasis on biomedical problems related to the selenium status of humans and experimental animals. Historical milestones of selenium biochemistry starting from the identification of the first selenoenzymes up to the elucidation of prokaryotic and eukaryotic selenoprotein boisynthesis are compiled. Topical hypotheses on the biological role of selenium in general and of individual selenoproteins in respect to antioxidant defense, redox regulation of metabolic processes, thyroid function, spermatogenesis, oncogenesis, and atherogenesis are critically evaluated.
The Emp24 Complex Recruits a Specific Cargo Molecule into Endoplasmic Reticulum–Derived Vesicles
Authors: Muñiz Manuel , Nuoffer Claude , Hauri Hans-Peter , Riezman Howard
Published: July 2002

Members of the yeast p24 family, including Emp24p and Erv25p, form a heteromeric complex required for the efficient transport of selected proteins from the endoplasmic reticulum (ER) to the Golgi apparatus. The specific functions and sites of action of this complex are unknown. We show that Emp24p is directly required for efficient packaging of a lumenal cargo protein, Gas1p, into ER-derived vesicles. Emp24p and Erv25p can be directly cross-linked to Gas1p in ER-derived vesicles. Gap1p, which was not affected by emp24 mutation, was not cross-linked. These results suggest that the Emp24 complex acts as a cargo receptor in vesicle biogenesis from the ER.
Interleukin 6 Influences Germinal Center Development and Antibody Production via a Contribution of C3 Complement Component
Authors: Kopf Manfred , Herren Suzanne , Wiles Michael V. , Pepys Mark B. , Kosco-Vilbois Marie H.
Published: July 2002

Mice rendered deficient for interleukin (IL) 6 by gene targeting were evaluated for their response to T cell–dependent antigens. Antigen-specific immunoglobulin (Ig)M levels were unaffected whereas all IgG isotypes showed varying degrees of alteration. Germinal center reactions occurred but remained physically smaller in comparison to those in the wild-type mice. This concurred with the observations that molecules involved in initial signaling events leading to germinal center formation were not altered (e.g., B7.2, CD40 and tumor necrosis factor R1). T cell priming was not impaired nor was a gross imbalance of T helper cell (Th) 1 versus Th2 cytokines observed. However, B7.1 molecules, absent from wild-type counterparts, were detected on germinal center B cells isolated from the deficient mice suggesting a modification of costimulatory signaling. A second alteration involved impaired de novo synthesis of C3 both in serum and germinal center cells from IL-6–deficient mice. Indeed, C3 provided an essential stimulatory signal for wild-type germinal center cells as both monoclonal antibodies that interrupted C3-CD21 interactions and sheep anti–mouse C3 antibodies caused a significant decrease in antigen-specific antibody production. In addition, germinal center cells isolated from C3–deficient mice produced a similar defect in isotype production. Low density cells with dendritic morphology were the local source of IL-6 and not the germinal center lymphocytes. Adding IL-6 in vitro to IL-6–deficient germinal center cells stimulated cell cycle progression and increased levels of antibody production. These findings reveal that the germinal center produces and uses molecules of the innate immune system, evolutionarily pirating them in order to optimally generate high affinity antibody responses.
Normal Regulatory α/β T Cells Effectively Eliminate Abnormally Activated T Cells Lacking the Interleukin 2 Receptor β in Vivo
Authors: Suzuki Haruhiko , Zhou Yan Wen , Kato Masashi , Mak Tak W. , Nakashima Izumi
Published: July 2002

Although interleukin 2 (IL-2) has been thought to be the most important cytokine for T cell growth, animals lacking IL-2 or a component of its receptor molecules have more expanded T cells with activated memory phenotype, indicating an indispensable role for the IL-2/IL-2 receptor system in regulating the size and activity of the T cell population. In this study, we investigated the possible mechanism of abnormal expansion of activated T cells in IL-2 receptor β chain (IL-2Rβ)−/− mice using the systems of bone marrow transplantation and T cell transfer. Here, we show that IL-2Rβ2/− T cells in mice reconstituted with a mixture of IL-2Rβ2/− and IL-2Rβ1/+ bone marrow cells did not develop into an abnormally activated stage, and that already activated IL-2Rβ2/− T cells were effectively eliminated by IL-2Rβ1/+ T cells when both cells were cotransferred to T cell–deficient host mice. This regulation and/or elimination was dependent on T cells bearing α/β type T cell receptor, especially on CD8+ T cells and independent of the Fas–Fas ligand (FasL) system. IL-2Rβ1/+ T cells that eliminated activated IL-2Rβ2/− T cells expressed FasL, perforin, granzyme B, and tumor necrosis factor α/β. These results indicate a novel function of IL-2Rβ that is necessary for the induction of regulatory T cells acting to eliminate activated T cells.
Cd4+ T Cell Subsets during Virus Infection
Authors: Maloy Kevin J. , Burkhart Christoph , Junt Tobias M. , Odermatt Bernhard , Oxenius Annette , Piali Luca , Zinkernagel Rolf M. , Hengartner Hans
Published: July 2002

To analyze the antiviral protective capacities of CD4+ T helper (Th) cell subsets, we used transgenic T cells expressing an I-Ab–restricted T cell receptor specific for an epitope of vesicular stomatitis virus glycoprotein (VSV-G). After polarization into Th1 or Th2 effectors and adoptive transfer into T cell–deficient recipients, protective capacities were assessed after infection with different types of viruses expressing the VSV-G. Both Th1 and Th2 CD4+ T cells could transfer protection against systemic VSV infection, by stimulating the production of neutralizing immunoglobulin G antibodies. However, only Th1 CD4+ T cells were able to mediate protection against infection with recombinant vaccinia virus expressing the VSV-G (Vacc-IND-G). Similarly, only Th1 CD4+ T cells were able to rapidly eradicate Vacc-IND-G from peripheral organs, to mediate delayed-type hypersensitivity responses against VSV-G and to protect against lethal intranasal infection with VSV. Protective capacity correlated with the ability of Th1 CD4+ T cells to rapidly migrate to peripheral inflammatory sites in vivo and to respond to inflammatory chemokines that were induced after virus infection of peripheral tissues. Therefore, the antiviral protective capacity of a given CD4+ T cell is governed by the effector cytokines it produces and by its migratory capability.
Arrested B Lymphopoiesis and Persistence of Activated B Cells in Adult Interleukin 7−/− Mice
Authors: Carvalho Thiago L. , Mota-Santos Tomaz , Cumano Ana , Demengeot Jocelyne , Vieira Paulo
Published: July 2002

Interleukin 7 is a crucial factor for the development of murine T and B lymphocytes. We now report that, in the absence of interleukin 7, B lymphocyte production takes place exclusively during fetal and perinatal life, ceasing after 7 wk of age. In peripheral organs, however, the pool of B lymphocytes is stable throughout adult life and consists only of cells that belong to the B1 and marginal zone (MZ) compartments. This is accompanied by a 50-fold increase in the frequency of immunoglobulin (Ig)M- and IgG-secreting cells, and the concentration of serum immunoglobulins is increased three- to fivefold. Both the MZ phenotype and the increase in serum IgM are T cell independent. These findings reveal a previously undescribed pathway of B lymphopoiesis that is active in early life and is interleukin 7 independent. This pathway generates B1 cells and a normal sized MZ B lymphocyte compartment.
Voltage Dependence of Slow Inactivation in Shaker Potassium Channels Results from Changes in Relative K+ and Na+ Permeabilities
Authors: Starkus John G. , Heinemann Stefan H. , Rayner Martin D.
Published: July 2002

Time constants of slow inactivation were investigated in NH2-terminal deleted Shaker potassium channels using macro-patch recordings from Xenopus oocytes. Slow inactivation is voltage insensitive in physiological solutions or in simple experimental solutions such as K+o//K+i or Na+o//K+i. However, when [Na+]i is increased while [K+]i is reduced, voltage sensitivity appears in the slow inactivation rates at positive potentials. In such solutions, the I-V curves show a region of negative slope conductance between ∼0 and +60 mV, with strongly increased outward current at more positive voltages, yielding an N-shaped curvature. These changes in peak outward currents are associated with marked changes in the dominant slow inactivation time constant from ∼1.5 s at potentials less than approximately +60 mV to ∼30 ms at more than +150 mV. Since slow inactivation in Shaker channels is extremely sensitive to the concentrations and species of permeant ions, more rapid entry into slow inactivated state(s) might indicate decreased K+ permeation and increased Na+ permeation at positive potentials. However, the N-shaped I-V curve becomes fully developed before the onset of significant slow inactivation, indicating that this N-shaped I-V does not arise from permeability changes associated with entry into slow inactivated states. Thus, changes in the relative contributions of K+ and Na+ ions to outward currents could arise either: (a) from depletions of [K+]i sufficient to permit increased Na+ permeation, or (b) from voltage-dependent changes in K+ and Na+ permeabilities. Our results rule out the first of these mechanisms. Furthermore, effects of changing [K+]i and [K+]o on ramp I-V waveforms suggest that applied potential directly affects relative permeation by K+ and Na+ ions. Therefore, we conclude that the voltage sensitivity of slow inactivation rates arises indirectly as a result of voltage-dependent changes in the ion occupancy of these channels, and demonstrate that simple barrier models can predict such voltage-dependent changes in relative permeabilities.
Extracellular Hco3− Dependence of Electrogenic Na/Hco3 Cotransporters Cloned from Salamander and Rat Kidney
Authors: Grichtchenko Irina I. , Romero Michael F. , Boron Walter F.
Published: July 2002

We studied the extracellular [HCOabstract 3 −] dependence of two renal clones of the electrogenic Na/HCO3 cotransporter (NBC) heterologously expressed in Xenopus oocytes. We used microelectrodes to measure the change in membrane potential (ΔVm) elicited by the NBC cloned from the kidney of the salamander Ambystoma tigrinum (akNBC) and by the NBC cloned from the kidney of rat (rkNBC). We used a two-electrode voltage clamp to measure the change in current (ΔI) elicited by rkNBC. Briefly exposing an NBC-expressing oocyte to HCOabstract 3 −/CO2 (0.33–99 mM HCOabstract 3−, pHo 7.5) elicited an immediate, DIDS (4,4-diisothiocyanatostilbene-2,2-disulfonic acid)-sensitive and Na+-dependent hyperpolarization (or outward current). In ΔVm experiments, the apparent Km for HCOabstract 3− of akNBC (10.6 mM) and rkNBC (10.8 mM) were similar. However, under voltage-clamp conditions, the apparent Km for HCOabstract 3− of rkNBC was less (6.5 mM). Because it has been reported that SOabstract 3=/HSO abstract 3− stimulates Na/HCO3 cotransport in renal membrane vesicles (a result that supports the existence of a COabstract 3= binding site with which SOabstract 3= interacts), we examined the effect of SOabstract 3=/HSO abstract 3− on rkNBC. In voltage-clamp studies, we found that neither 33 mM SOabstract 4= nor 33 mM SOabstract 3 =/HSOabstract 3− substantially affects the apparent Km for HCO abstract 3−. We also used microelectrodes to monitor intracellular pH (pHi) while exposing rkNBC-expressing oocytes to 3.3 mM HCOabstract 3 −/0.5% CO2. We found that SO abstract 3=/HSOabstract 3 − did not significantly affect the DIDS-sensitive component of the pHi recovery from the initial CO2 -induced acidification. We also monitored the rkNBC current while simultaneously varying [CO2]o, pHo, and [COabstract 3=]o at a fixed [HCOabstract 3−]o of 33 mM. A Michaelis-Menten equation poorly fitted the data expressed as current versus [COabstract 3=]o . However, a pH titration curve nicely fitted the data expressed as current versus pHo. Thus, rkNBC expressed in Xenopus oocytes does not appear to interact with SOabstract 3 =, HSOabstract 3−, or COabstract 3=.
Not all Julia sets are quasi-self-similar
Authors: Järvi Pentti
Published: July 2002

We show that there exist rational functions, whose Julia set fails to be quasi-self-similar.
A short proof for the stability theorem for positive semigroups on 𝐿_{𝑝}(𝜇)
Authors: Weis Lutz
Published: July 2002

We give a short proof showing that the growth bound of a positive semigroup on

L
p

(
μ
)

L_p(\mu )

equals the spectral bound of its generator. It is based on a new boundedness theorem for positive convolution operators on

L
p

(

L
q

)

L_p(L_q)

. We also give a counterexample, showing that Gearhart’s result does not extend from Hilbert spaces to

L
p

(
μ
)

L_p(\mu )

-spaces.
A note on norm attaining functionals
Authors: Sevilla M. , Moreno J.
Published: July 2002

We are concerned in this paper with the density of functionals which do not attain their norms in Banach spaces. Some earlier results given for separable spaces are extended to the nonseparable case. We obtain that a Banach space

X
X

is reflexive if and only if it satisfies any of the following properties: (i)

X
X

admits a norm

‖
⋅
‖

\|\cdot \|

with the Mazur Intersection Property and the set

N

A

‖
⋅
‖

NA_{\|\cdot \|}

of all norm attaining functionals of

X
∗

X^*

contains an open set, (ii) the set

N

A

‖
⋅
‖

1

NA^1_{\|\cdot \|}

of all norm one elements of

N

A

‖
⋅
‖

NA_{\|\cdot \|}

contains a (relative) weak* open set of the unit sphere, (iii)

X
∗

X^*

has

C
∗

P
C
P

C^*PCP

and

N

A

‖
⋅
‖

1

NA^1_{\|\cdot \|}

contains a (relative) weak open set of the unit sphere, (iv)

X
X

is

W
C
G

WCG

,

X
∗

X^*

has

C
P
C
P

CPCP

and

N

A

‖
⋅
‖

1

NA^1_{\|\cdot \|}

contains a (relative) weak open set of the unit sphere. Finally, if

X
X

is separable, then

X
X

is reflexive if and only if

N

A

‖
⋅
‖

1

NA^1_{\|\cdot \|}

contains a (relative) weak open set of the unit sphere.
Counting solutions to trinomial Thue equations: a different approach
Authors: Thomas Emery
Published: July 2002

We consider the problem of counting solutions to a trinomial Thue equation — that is, an equation

(

∗

)

|

F
(
x
,
y
)

|

=
1
,

\begin{equation*} |F(x,y)| = 1,\tag {$*$} \end{equation*}

where

F
F

is an irreducible form in

Z
[
x
,
y
]

Z[x,y]

with degree at least three and with three non-zero coefficients. In a 1987 paper J. Mueller and W. Schmidt gave effective bounds for this problem. Their work was based on a series of papers by Bombieri, Bombieri-Mueller and Bombieri-Schmidt, all concerned with the “Thue-Siegel principle" and its relation to

(
∗
)

(*)

. In this paper we give specific numerical bounds for the number of solutions to

(
∗
)

(*)

by a somewhat different approach, the difference lying in the initial step — solving a certain diophantine approximation problem. We regard this as a real variable extremal problem, which we then solve by elementary calculus.
Wandering vectors for irrational rotation unitary systems
Authors: Han Deguang
Published: July 2002

An abstract characterization for those irrational rotation unitary systems with complete wandering subspaces is given. We prove that an irrational rotation unitary system has a complete wandering vector if and only if the von Neumann algebra generated by the unitary system is finite and shares a cyclic vector with its commutant. We solve a factorization problem of Dai and Larson negatively for wandering vector multipliers, and strengthen this by showing that for an irrational rotation unitary system

U

\mathcal {U}

, every unitary operator in

w

∗

(

U

)

w^{*}(\mathcal {U})

is a wandering vector multiplier. Moreover, we show that there is a class of wandering vector multipliers, induced in a natural way by pairs of characters of the integer group

Z

\mathbb {Z}

, which fail to factor even as the product of a unitary in

U

′

\mathcal {U}’

and a unitary in

w

∗

(

U

)

w^{*}(\mathcal {U})

. Incomplete maximal wandering subspaces are also considered, and some questions are raised.
Toeplitz operators with PC symbols on general Carleson Jordan curves with arbitrary Muckenhoupt weights
Authors: Böttcher Albrecht , Karlovich Yuri
Published: July 2002

We describe the spectra and essential spectra of Toeplitz operators with piecewise continuous symbols on the Hardy space

H
p

(
Γ
,
ω
)

H^p(\Gamma ,\omega )

in case

1
>
p
>
∞

1>p>\infty

,

Γ
\Gamma

is a Carleson Jordan curve and

ω
\omega

is a Muckenhoupt weight in

A
p

(
Γ
)

A_p(\Gamma )

. Classical results tell us that the essential spectrum of the operator is obtained from the essential range of the symbol by filling in line segments or circular arcs between the endpoints of the jumps if both the curve

Γ
\Gamma

and the weight are sufficiently nice. Only recently it was discovered by Spitkovsky that these line segments or circular arcs metamorphose into horns if the curve

Γ
\Gamma

is nice and

ω
\omega

is an arbitrary Muckenhoupt weight, while the authors observed that certain special so-called logarithmic leaves emerge in the case of arbitrary Carleson curves with nice weights. In this paper we show that for general Carleson curves and general Muckenhoupt weights the sets in question are logarithmic leaves with a halo, and we present final results concerning the shape of the halo.
Finding prime pairs with particular gaps
Authors: Cutter Pamela
Published: July 2002

By a prime gap of size

g
g

, we mean that there are primes

p
p

and

p
+
g

p+g

such that the

g
−
1

g-1

numbers between

p
p

and

p
+
g

p+g

are all composite. It is widely believed that infinitely many prime gaps of size

g
g

exist for all even integers

g
g

. However, it had not previously been known whether a prime gap of size

1000
1000

existed. The objective of this article was to be the first to find a prime gap of size

1000
1000

, by using a systematic method that would also apply to finding prime gaps of any size. By this method, we find prime gaps for all even integers from

746
746

to

1000
1000

, and some beyond. What we find are not necessarily the first occurrences of these gaps, but, being examples, they give an upper bound on the first such occurrences. The prime gaps of size

1000
1000

listed in this article were first announced on the Number Theory Listing to the World Wide Web on Tuesday, April 8, 1997. Since then, others, including Sol Weintraub and A.O.L. Atkin, have found prime gaps of size

1000
1000

with smaller integers, using more ad hoc methods. At the end of the article, related computations to find prime triples of the form

6
m
+
1

6m+1

,

12
m
−
1

12m-1

,

12
m
+
1

12m+1

and their application to divisibility of binomial coefficients by a square will also be discussed.
Simultaneous Pell equations
Authors: Anglin W.
Published: July 2002

Let

R
R

and

S
S

be positive integers with

R
>
S

R>S

. We shall call the simultaneous Diophantine equations

x
2

−
R

y
2

a
m
p
;
=
1
,
 

z
2

−
S

y
2

a
m
p
;
=
1

\begin{align*} x^2-Ry^2&=1,\ z^2-Sy^2&=1 \end{align*}

simultaneous Pell equations in

R
R

and

S
S

. Each such pair has the trivial solution

(
1
,
0
,
1
)

(1,0,1)

but some pairs have nontrivial solutions too. For example, if

R
=
11

R=11

and

S
=
56

S=56

, then

(
199
,
60
,
449
)

(199, 60, 449)

is a solution. Using theorems due to Baker, Davenport, and Waldschmidt, it is possible to show that the number of solutions is always finite, and it is possible to give a complete list of them. In this paper we report on the solutions when

R
>
S
≤
200

R>S\le 200

.
Checking the odd Goldbach conjecture up to 10²⁰
Authors: Saouter Yannick
Published: July 2002

Vinogradov’s theorem states that any sufficiently large odd integer is the sum of three prime numbers. This theorem allows us to suppose the conjecture that this is true for all odd integers. In this paper, we describe the implementation of an algorithm which allowed us to check this conjecture up to

10

20

10^{20}

.
p38 Mitogen-activated Protein Kinase-, Calcium-Calmodulin–dependent Protein Kinase-, and Calcineurin-mediated Signaling Pathways Transcriptionally Regulate Myogenin Expression
Authors: Xu Qing , Yu Lu , Liu Lanying , Cheung Ching Fung , Li Xue , Yee Siu-Pok , Yang Xiang-Jiao , Wu Zhenguo
Published: July 2002

In this report, we identify myogenin as an important transcriptional target under the control of three intracellular signaling pathways, namely, the p38 mitogen-activated protein kinase- (MAPK), calcium-calmodulin–dependent protein kinase- (CaMK), and calcineurin-mediated pathways, during skeletal muscle differentiation. Three cis-elements (i.e., the E box, myocyte enhancer factor [MEF] 2, and MEF3 sites) in the proximal myogenin promoter in response to these three pathways are defined. MyoD, MEF2s, and Six proteins, the trans-activators bound to these cis-elements, are shown to be activated by these signaling pathways. Our data support a model in which all three signaling pathways act in parallel but nonredundantly to control myogenin expression. Inhibition of any one pathway will result in abolished or reduced myogenin expression and subsequent phenotypic differentiation. In addition, we demonstrate that CaMK and calcineurin fail to activate MEF2s in Rhabdomyosarcoma-derived RD cells. For CaMK, we show its activation in response to differentiation signals and its effect on the cytoplasmic translocation of histone deacetylases 5 are not compromised in RD cells, suggesting histone deacetylases 5 cytoplasmic translocation is necessary but not sufficient, and additional signal is required in conjunction with CaMK to activate MEF2 proteins.
Transcription regulatory region analysis using signal detection and fuzzy clustering.
Authors: Pickert L , Reuter I , Klawonn F , Wingender E
Published: July 2002

MOTIVATION: Presently available programs for the recognition of potential transcription factor binding sites in genomic sequences generally yield a huge amount of output. These output lists have to be filtered to obtain biologically significant elements, which is highly laborious work to be done manually. RESULTS: We developed a strategy for systematic verification and improvement of the underlying profiles, and for their contextual analysis by a fuzzy clustering approach using non-redundant libraries of search profiles as a prerequisite. AVAILABILITY: The tools mentioned in the paper are available upon request. CONTACT: ewi@gbf.de
Black Is Profitable: The Commodification of the Afro, 1960–1975
Authors: Walker Susannah
Published: July 2002

The Afro originated in the United States as a style worn by a tiny minority of cosmopolitan black women and developed as a prominent symbol of racial pride in the mid-1960s. Responding to the Afro's grassroots popularity, the African American beauty culture industry mounted a largely successful effort to transform the style from political statement to fashion commodity. But the commodification of the Afro was not exclusively a cynical exploitation of a political symbol. Rather, the selling of the Afro often entailed a complex blending of ideals, goals, and motivations based, to varying degrees, on considerations of fashion, politics, and the bottom line.
Antimicrobial activity and accumulation of moxifloxacin in quinolone-susceptible bacteria
Authors: Piddock Laura J. V. , Jin Yu Fang
Published: July 2002

The antibacterial activity of moxifloxacin, compared with that of ciprofloxacin, was determined for five strains of Staphylococcus aureus, including one NorA-overproducing strain, two quinolone-susceptible strains of Streptococcus pneumoniae, four quinolone-susceptible strains of Haemophilus influenzae, and one strain each of quinolone-susceptible Escherichia coli,Pseudomonas aeruginosa and Moraxella catarrhalis. In addition, the accumulation of moxifloxacin and ciprofloxacin by the NCTC type strain of S. pneumoniae,H. influenzae,S. aureus,E. coli and P. aeruginosa was determined by a fluorescence method. For all strains, moxifloxacin accumulated to a lower concentration than ciprofloxacin. The concentrations of moxifloxacin accumulated ranged from 12 to 44 ng/mg dry cells. The lowest concentration was accumulated by S. pneumoniae NCTC 7465 and the highest concentration by S. aureus NCTC 8532. Increased expression of norA in S. aureus had no effect on the accumulation of moxifloxacin. Despite differences in the concentration of moxifloxacin accumulated by the different species, there was little difference between the MICs of this agent for each strain (0.06–0.5 mg/L), suggesting that the concentration accumulated by wild-type bacteria has little effect on the MIC.
Optimal treatment of complicated skin and skin structure infections
Authors: Nichols Ronald Lee
Published: July 2002

Gram-positive bacteria (e.g. Staphylococcus aureus and Streptococcus pyogenes) are the main cause of skin and skin structure infections (SSSI). Treatment presents a clinical challenge to the physician, particularly with the increase in multidrug-resistant strains and widespread cross-resistance to antibiotic treatment. Initial treatment of SSSI involves the use of fluoroquinolones or penicillinase-resistant penicillins. If infection is caused by methicillin-resistant staphylococci, therapy with glycopeptides is warranted. However, in the last few years several cases of infection caused by strains of S. aureuswith reduced susceptibility to glycopeptides have been reported. Quinupristin/dalfopristin is a new streptogramin that has shown efficacy in the management of multidrug-resistant Gram-positive infections. Two major studies suggest that in the treatment of complicated SSSI, the clinical efficacy of quinupristin/dalfopristin is equivalent to that of vancomycin and/or oxacillin and vancomycin and/or cefazolin.
Global similarity solutions to a class of semilinear parabolic equations: existence, bifurcations and asymptotics
Authors: Needham D. J. , Chamberlain P. G.
Published: July 2002

This paper examines the existence, structure and bifurcation (in the parametersNandp) of a class of global positive similarity solutions to the semilinear parabolic equationut= ∇N2u+up, withp> 1 andN⩾ 1. Here ∇N2is theN–dimensional Laplace operator. These are related to the existence of‘geometric threshold’ in thepth–order autocatalytic or chain–branching reactions.
Signal transduction in the wound response of tomato plants
Authors: Bowles Dianna
Published: July 2002

The wound response of tomato plants has been extensively studied, and provides a useful model to understand signal transduction events leading from injury to marker gene expression. The principal markers that have been used in these studies are genes encoding proteinase inhibitor (pin) proteins. Activation of
pin
genes occurs in the wounded leaf and in distant unwounded leaves of the plant. This paper reviews current understanding of signalling pathways in the wounded leaf, and in the systemically responding unwounded leaves. First, the nature of known elicitors and their potential roles
in planta
are discussed, in particular, oligogalacturonides, jasmonates and the peptide signal, systemin. Inhibitors of wound–induced proteinase inhibitor (pin) expression are also reviewed, with particular reference to phenolics, sulphydryl reagents and fusicoccin. In each section, results obtained from the bioassay are considered within the wider context of data from mutants and from transgenic plants with altered levels of putative signalling components. Following this introduction, current models for
pin
gene regulation are described and discussed, together with a summary for the involvement of phosphorylation–dephosphorylation in wound signalling. Finally, a new model for wound–induced
pin
gene expression is presented, arising from recent data from the author‘apos; laboratory.
Analysis of the connectional organization of neural systems associated with the hippocampus in rats
Authors: Burns Gully A. P. C. , Young Malcolm P.
Published: July 2002

The hippocampus of the rat enjoys a central significance for researchers interested in the neural mechanisms of memory and spatial information processing. Many of the theoretical models advanced to explain function in this system, however, do not reflect the wealth of information on the connectivity of these structures, and employ greatly simplified treatments of its complex connectivity. W e were interested in whether a more analytical approach, which begins with analysis of the connectivity of the system, might provide insights complementary to those derived by synthetic models. Accordingly, we collated detailed neuroanatomical information about the connectivity of the hippocampal system in the rat, and analysed the resulting data. Analyses of connectivity based on a variety of different analytical techniques have recently been used to elucidate the global organization of other systems in the macaque and cat, and have given rise to successful predictions. W e applied non–metric multidimensional scaling and non–parametric cluster analysis to our summary matrix of connection data. The analyses produced organizational schemes that were consistent with known physiological properties and provided the basis for making tentative predictions of the further structures that may contain ‘place’ and ‘head–direction’ cells, which structures we identify. The consistency between the analyses of connectivity and the distribution of physiological properties across the system suggests that functional relationships are constrained by the organization of the connectivity of the system, and so that structure and function are linked at the systems level.
Computer‐aided diagnosis: Automatic detection of malignant masses in digitized mammograms
Authors: Méndez Arturo J. , Tahoces Pablo G. , Lado Marı́a J. , Souto Miguel , Vidal Juan J.
Published: July 2002

A computerized method to automatically detect malignant masses on digital mammograms based on bilateral subtraction to identify asymmetries between left and right breast images was developed. After the digitization, in order to align left and right mammograms the breast border and nipple were automatically detected. Images were corrected to avoid differences in brightness due to the recording procedure. Left and right mammograms were subtracted and a threshold was applied to obtain a binary image with the information of suspicious areas. The suspicious regions or asymmetries were delimited by a region growing algorithm. Size and eccentricity tests were used to eliminate false‐positive responses and texture features were extracted from suspicious regions to reject normal tissue regions. The scheme, tested in 70 pairs of digital mammograms, achieved a true‐positive rate of 71% with an average number of 0.67 false positives per image. Computerized detection was evaluated by using free‐response operating characteristic analysis (FROC). An area under the AFROC of 0.667 was obtained. Our results show that the scheme may be helpful to the radiologists by serving as a second reader in mammographic screening. The low number of false positives indicates that our scheme would not confuse the radiologist by suggesting normal regions as suspicious.
Radiation dose in Spiral CT: The relative effects of collimation and pitch
Authors: McNitt‐Gray Michael F. , Cagnon Christopher H. , Solberg Timothy D. , Chetty Indrin
Published: July 2002

The proliferation of helical CT and thin slice protocols has motivated a reevaluation of methods for determining radiation dose. Traditional measurements may be insufficient in that computed tomography dose index (CTDI) is undefined for the case of continuous table motion which characterizes helical CT. We have measured the radiation dose using thermoluminescent dosimeters (TLDs) under contiguous axial, contiguous helical, and noncontiguous helical scans. A device that holds tightly spaced TLDs was inserted into a 32‐cm‐diam Plexiglas™ (CTDI) phantom so that (1) TLDs were exposed to contiguous axial scans; (2) TLDs were exposed to a contiguous (pitch 1) helical scans, and (3) TLDs were exposed to noncontiguous (pitch >1) helical scans. The TLDs integrated exposure from both primary and scattered radiation resulting from scanning a volume of the phantom. The TLD measurements were repeated at several slice thicknesses and for pitches of 1, 1.5, and 2. For a direct comparison, conventional pencil ionization chamber measurements were made at the same slice thicknesses. Our results show that contiguous helical CT scans (pitch of 1) give approximately the same radiation dose as contiguous axial scans acquired with the same technical factors. For noncontiguous scans (pitch >1) at a given collimation, radiation dose decreases as pitch increases; specifically as 1/pitch. However, the dose remained relatively constant across collimations (±20% of the 10 mm slice dose) for both axial and helical scans. At smaller slice thicknesses, the radiation profile width (full width at half‐maximum) is greater than the nominal slice thickness, which results in extended radiation overlap between slices and no net change in radiation dose compared to thicker slices. Finally, for a given table speed, radiation dose decreases when a higher pitch is used with a thinner collimation.
Glottal flow through a two-mass model: Comparison of Navier–Stokes solutions with simplified models
Authors: de Vries M. P. , Schutte H. K. , Veldman A. E. P. , Verkerke G. J.
Published: July 2002

A new numerical model of the vocal folds is presented based on the well-known two-mass models of the vocal folds. The two-mass model is coupled to a model of glottal airflow based on the incompressible Navier–Stokes equations. Glottal waves are produced using different initial glottal gaps and different subglottal pressures. Fundamental frequency, glottal peak flow, and closed phase of the glottal waves have been compared with values known from the literature. The phonation threshold pressure was determined for different initial glottal gaps. The phonation threshold pressure obtained using the flow model with Navier–Stokes equations corresponds better to values determined in normal phonation than the phonation threshold pressure obtained using the flow model based on the Bernoulli equation. Using the Navier–Stokes equations, an increase of the subglottal pressure causes the fundamental frequency and the glottal peak flow to increase, whereas the fundamental frequency in the Bernoulli-based model does not change with increasing pressure.
Aero-acoustics of silicone rubber lip reeds for alternative voice production in laryngectomees
Authors: van der Torn Marein , Mahieu Hans F. , Festen Joost M.
Published: July 2002

To improve voice quality after laryngectomy, a small pneumatic sound source to be incorporated in a regular tracheoesophageal shunt valve was designed. This artificial voice source consists of a single floppy lip reed, which performs self-sustaining flutter-type oscillations driven by the expired pulmonary air that flows through the tracheoesophageal shunt valve along the outward-striking lip reed. In this in vitro study, aero-acoustic data and detailed high-speed digital image sequences of lip reed behavior are obtained for 10 lip configurations. The high-speed visualizations provide a more explicit understanding and reveal details of lip reed behavior, such as the onset of vibration, beating of the lip against the walls of its housing, and chaotic behavior at high volume flow. We discuss several aspects of lip reed behavior in general and implications for its application as an artificial voice source. For pressures above the sounding threshold, volume flow, fundamental frequency and sound pressure level generated by the floppy lip reed are almost linear functions of the driving force, static pressure difference across the lip. Observed irregularities in these relations are mainly caused by transitions from one type of beating behavior of the lip against the walls of its housing to another. This beating explains the wide range and the driving force dependence of fundamental frequency, and seems to have a strong effect on the spectral content. The thickness of the lip base is linearly related to the fundamental frequency of lip reed oscillation.
The forward projection of harmonic pressure fields using the generalized internal source density method
Authors: Stepanishen Peter R.
Published: July 2002

A previously developed generalized internal source density (GISD) method is extended to address the forward projection of harmonic pressure fields from normal velocity fields on a closed surface of revolution in a fluid. The GISD approach is based on decomposing the normal velocity field on the closed surface into a summation of circumferential orders where the pressure field for each order is associated with an internal linear source distribution of ring sources on the axis of revolution of the surface. The linear source distributions are formulated as integral equations of the first kind which are then solved using singular value decomposition methods. Far-field pressures are simply related to the Fourier transforms of the linear source distributions. Numerical results are presented to illustrate the forward projection of harmonic fields using the GISD method for both Dirichlet and Neumann problems. The numerical results for spherical and finite cylindrical vibrators illustrate the usefulness of the GISD method over a wide range of frequencies for both acoustic radiation and scattering problems.
Basic characteristics of click-evoked otoacoustic emissions in infants and children
Authors: Prieve Beth A. , Fitzgerald Tracy S. , Schulte Laura E.
Published: July 2002

Since Kemp [J. Acoust. Soc. Am. 64, 1386–1391 (1978)] first described click-evoked otoacoustic emissions (COAEs), researchers have advocated their use as an excellent tool for diagnosing hearing loss in infants and children. However, there are few detailed reports of COAEs in this population, and those that do exist suggest that there are age-dependent differences. The purpose of the current study was to determine basic characteristics of COAEs in infants, toddlers, children, and young adults and to define any differences among age groups. An additional goal was to ensure that spontaneous otoacoustic emissions (SOAEs) did not confound any possible developmental effects. COAEs and SOAEs were measured from one ear of 223 normal-hearing subjects. COAE input/output functions indicated that children aged less than one year have higher COAE levels than older children and adults. Children aged 1–5 yr had higher COAE levels than those aged 12–17 yr and adults. These differences were independent of level and SOAE status, but were dependent on frequency. The results of this study suggest that different clinical norms may be necessary for children aged less than 6 years.
Cross-modality matching and the loudness growth function for click stimuli
Authors: Serpanos Yula C. , O’Malley Honor , Gravel Judith S.
Published: July 2002

Loudness-intensity functions for click stimuli were obtained from 30 adult listeners having normal (n=10), flat (n=10), or sloping (n=10) high-frequency cochlear hearing loss configurations. The procedure of cross-modality matching (CMM) between loudness and perceived line length [R. P. Hellman and C. H. Meiselman, J. Speech Hear. Res. 31, 605–615 (1988); J. Acoust. Soc. Am. 88, 2596–2606 (1990); J. Acoust. Soc. Am. 93, 966–975 (1993)] was used to validate their loudness growth functions. Mean group loudness exponents were similar to those reported in recent investigations that utilized pure tone stimuli, further supporting the validity and reliability of the CMM task as an estimate of the loudness growth function. The results also suggest that the mean loudness function for clicks is similar to the function obtained with tonal stimuli at least for listeners with moderately impaired hearing or better. Moreover, CMM produced less variability than the more conventional psychophysical methods of magnitude estimation and production for the groups with cochlear hearing loss. Toward direct application of the CMM technique, in lieu of absolute exponential slope values, the individually determined loudness growth function over a range of intensities should be compared to the normal mean function for calculations of deviations.
Application of the integral equation method to acoustic wave diffraction from elastic bodies in a fluid layer
Authors: Belov Valentin E. , Gorsky Sergey M. , Zalezsky Alexey A. , Zinovyev Alexey Y.
Published: July 2002

A method is proposed for solving the wave diffraction problem by employing a system of N space-localized inhomogeneities in a longitudinally homogeneous waveguide. The method combines integral equations and eigenfunction methods. As an illustration of this method, acoustic diffraction is calculated from a system of N, different, parallel cylinders arbitrarily placed in a liquid layer. The problem is reduced to a system of 2N integral-functional equations relative to fields excited in elastic bodies and sources of scattered waves on the surface of the cylinders. Standard methods may be used for solving the systems of equations. Numerical solutions are found for various versions of the system of elastic cylinders (N=1,2) in a liquid layer with perfectly “soft” and “hard” walls. The method allows: (1) the calculation of the scattering matrix for reflected and transmitted waves with any given accuracy; (2) the construction of the amplitude-frequency and the phase-frequency characteristics for the matrix elements; and (3) the calculation of the distribution of field sources on the surface of each cylinder and the scattered wave field both in the near and far zones.