bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Back Pain in Time: Risk Factors Associated with Persistence, Recurrence, and Time Till Patients Seek Help in Primary Care
Authors: Melloh M. , Stanton T. R. , Elfering A. 
Published: June 2012

Introduction Time characteristics of early episodes of low back pain (LBP) like duration and recurrence may relate to current risk factors and lack of resources that increase the risk of persistent LBP. In addition, when suffering from a first episode of LBP and individuals decide to seek medical care, time till individuals do should be not too long. Again, delay of presentation may relate to risk factors and lack of resources. Aim of our study was to estimate the relationship between time-related LBP characteristics and prognostic factors for acute/subacute LBP in primary care. Materials and Methods Prospective inception cohort study of 315 consecutive patients attending a health practitioner for their first episode of acute/subacute LBP or recurrent LBP. One-tailed correlations conducted between patient characteristics and the three time-related characteristics “subacute LBP”, “recurrent LBP,” and “delayed presentation”. Results The pattern of correlation between risk factors and resources against persistent LBP differed between three time-related variables. “Subacute LBP” and “delayed presentation” were positively associated with psychological factors (pain catastrophizing, magnification, and helplessness). Both indicators were negatively correlated with resources (job satisfaction and time control) against development of persistent LBP. Moreover, “delayed presentation” was related positively with occupational stressors (“resigned attitude towards the job”, “uncertainty”, “problem with organization of work tasks”, “work interruptions”). In contrast, “recurrent LBP” was only related to more impaired health-related factors (functional limitation, sensory, and affective pain). Conclusion Patients with current LBP waiting longer till seeking help in primary care have a more disadvantageous profile of occupational and psychological risk factors and lower resource levels. A similar but less pronounced pattern occurred in those with subacute LBP compared to those with acute LBP. Implications for clinical practice are twofold; (1) LBP-patients with prolonged symptoms or delayed care-seeking behavior, who are at risk of developing persistent LBP, should be screened for psychological factors such as magnification and helplessness, (2) In these patients, occupational resources like job satisfactionand time control should be addressed and strengthened in primary and secondary prevention, where feasible. Future research should examine time-related variables that influence prognostic factors for LBP in different clinical settings such as predominantly retired or unemployed populations. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Differential Intracellular Signaling Pathways Are Activated by Catabolic and Anabolic Factors in the Ivd, and these Could be Targeted in Selected Therapeutic Approaches
Authors: Daniels J. , Phillips K. L. , Chiverton N. , Le Maitre C. L. 
Published: June 2012

Introduction Intervertebral disk (IVD) degeneration is a major cause of lower back pain. Evidence suggests that inflammatory cytokines produced by chondrocyte-like cells within the IVD during degeneration are integral in the pathogenesis of this disease, with a particular role for IL-1 hypothesized. Targeting intracellular signaling mechanisms of IL-1 could provide a mechanism to inhibit multiple catabolic cytokines simultaneously. Many cytokines share intracellular signaling pathways and thus inhibiting signaling rather than direct receptors could prevent compensatory actions occurring. Here we investigated signaling pathways activated by IL-1 together with an anabolic factor to identify differential pathways. Materials and Methods Human nucleus pulposus (NP) cells were extracted via collagenase digestion and expanded in monolayer culture, prior to transfer to alginate bead culture for 2 weeks to enable redifferentiation. Following redifferentiation cells were treated with either IL-1 (10 ng/mL) or CDMP-1 (10 ng/ml) for 30 minutes, protein extracted and R&D proteome array deployed to investigate potential differential signaling molecules. In addition, NFkB activation was investigated using immuno-fluorescence and activation of pERK, pP38 MAPK, and AKT were investigated using BD phosflow techniques. In addition, cells were pretreated with inhibitors of signaling pathways: SB203580 (p38 MAPK) and Helenalin (NFkB) to investigate effects on matrix and matrix degrading enzyme gene expression following stimulation with CDMP and IL-1. Results R&D proteome array enabled the investigation of 46 signaling molecules simultaneously following and identified a number of differentially activated pathways, including p38MAPK (Fig. 1). IL-1 induced p38MAPK, NFkB, AKT, and ERK pathways were confirmed using BD phosflow and immunofluorescence techniques. Inhibition of NFkB pathway using helenine reduced the inhibitory effect on aggrecan induced by IL-1, but helenine alone also induced an inhibition of aggrecan induction by CDMP. Conclusion The catabolic cytokine IL-1 has been implicated in the pathogenesis of IVD degeneration which leads to low back pain. The identification of differential intracellular signaling pathways between anabolic and catabolic factors could provide new methods for modulating the catabolic response, and preventing further IVD degeneration. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Multiparametric Magnetic Resonance Imaging of Normal and Degenerative Lumbar Intervertebral Disks
Authors: Kim M. , Chan Q. , Anthony M. P. , Samartzis D. , Cheung K. , Khong P. 
Published: June 2012

Introduction Magnetic resonance imaging (MRI) has been shown to improve the diagnosis and management of patients with intervertebral disk (IVD) related disorders. Multiparametric MRI offers the possibility of noninvasively assessing multiple aspects of pathophysiological processes that exist simultaneously, thereby further assisting in patient treatment management. The purpose of this study is to determine the correlation between relaxation parameters (T1-rho and T2), diffusion properties including fractional anisotropy (FA) and mean diffusivity (MD) measured by diffusion tensor imaging (DTI), and degenerative grades in human IVD based on T2-weighted MRI. Materials and Methods Total 21 subjects (mean age 41.3 years; age range: 24 to 61 years; gender: 10 females, 11 males) with no prior spine surgery were recruited. Sagittal T2-weighted, T1-rho, T2, FA and MD MRI of the lumbar spine were obtained. All images of the lumbar spine were acquired using a 3T Achieva scanner. High-resolution T2-weighted discs were qualitatively graded by two spine specialists in consensus according to Schneiderman's classification (score range: 0 to 3). T1-rho, T2, FA, and MD maps were quantitatively assessed based on a voxel-by-voxel basis. Results By visual inspection, the nucleus pulposus (NP) and annulus fibrosus (AF) in IVDs were distinctively separable on all quantitative maps while some of the discs on T2-weighted images did not show a clear difference between the NP and the AF. The Schneiderman grades and subjects' age significantly correlated with all parameters ( p < 0.001). Univariate analysis demonstrated that T1-rho correlated significantly with MD and FA (r = 0.729 and −0.715, respectively; p < 0.001 for both). Quantitative T2 also correlated significantly with MD and FA (r = 0.805 and −0.811, respectively; p < 0.001 for both). In addition, T1-rho showed significant correlation with quantitative T2 (r = 0.824; p < 0.001). Conclusion In this study, we performed quantitative multiparametric MRI to investigate its sensitivity to changes in tissue microstructure of in vivo human lumbar IVDs. Our results suggest that each imaging parameter may attribute different sensitivity to tissue properties. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Histomorphometric and Radiographic Changes after Implantation of Peek-Interspinous Device in the BB.4Sd1 Rat Model
Authors: Melloh M. , Barz T. , Lange J. , Staub L. , Merk H. R. , Klöting I. , Follak N. 
Published: June 2012

Introduction Clinical effectiveness of the PEEK nonfusion interspinous device is well documented. However, there is a lack of evidence on the long-term behavior of this implant in regard to bone in general and especially its influence on structural changes of bone elements of the lumbar spine. Aim of our study was to investigate histomorphometric and radiographic changes in the BB.4Sd1 rat model after implantation of an interspinous PEEK implant. Materials and Methods Total 24 male BB.4Sd1 rats 11-week old underwent surgery for implantation of an interspinous PEEK device or for a sham procedure in three groups of eight animals each viz: (1) implantation at level L4-5, (2) implantation at level L5-6, and (3) sham surgery. Total 11 weeks postoperatively osteolyses at the implant-bone interface were measured via X-ray, bone mineral density of vertebral bodies was analyzed using osteodensitometry, and bone mineral content as well as osteolyses of the spinous processes examined by histomorphometry. Results Osteolyses of the spinous processes at the site of the interspinous implant were found in all treated segments. There was no significant difference in either bone density of vertebral bodies or histomorphometric structure of the spinous processes. Conclusion Osteolyses of spinous processes as a result of the implant becoming unsecure inhibit the targeted load redistribution through the interspinous PEEK device in the lumbar spinal segment of the rat. This leads to reduced long-term benefits of the implant in the animal model. These results suggest that the interspinous PEEK implants should only be used under strict indication and in consideration of their time-limited effects. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared Holinka J, Krepler P, Matzner M, et al. Stabilising effect of dynamic interspinous spacers in degenerative low-grade lumbar instability. International Orthopaedics 2011;35:395–400
Reconstitution of Nucleus Pulposus Cell Matrix Niche in 3D Configuration for Mesenchymal Stem Cell Differentiation
Authors: Yuan M. , Yeung C. W. , Chan B. P. 
Published: June 2012

Introduction Degenerative disk disease (DDD) is a medical condition whereby the intervertebral discs (IVD) of the human spine degenerates and causes pain which significantly affects the quality of one's life. A highly possible approach to overcome this problem is to produce injectable microspheres of similar composition to the native NP using MSCs to restore both its structural and functional properties. However, there is no systematic study in identifying the optimal conditions and signals for inducing MSCs differentiation toward nucleus pulposus (NP)-like phenotype. Materials and Methods In this project, we attempt to study the possibility to construct injectable microspheres with properties highly similar to that of native NP tissue using MSCs. Our approach was to culture NPCs within collagen microspheres whilst maintaining their phenotype and other characteristics, so that they would remodel the matrix microenvironment to one that was conducive for MSCs differentiation into new NPCs when MSCs were introduced upon removal of the original NPCs. Particular attention will be paid to the interaction between the MSCs and NPC-produced ECM to understand the mechanism for MSC differentiation. Results We demonstrated that NPCs could maintain survival within the collagen microspheres and produce NP-like ECM such as glycosaminoglycan (GAG) and Type II Collagen. GAG productions of NPCs were also found to positively correlate to the dosage of TGF-βwithin a period of 6 days. An optimized decellularization protocol was established to completely remove the encapsulated NPCs with partial retention of the GAG-rich matrix. The decellularized microspheres were able to be repopulated with hMSCs. With the effects of acellular matrices, these hMSCs were able to produce new NP-like ECM according to the results of histological, biochemical, immunohistological analysis, and real-time PCR. Conclusion The NPC derived acellular matrix is able to support growth of hMSC. Ongoing efforts are to assess the potential of the NPC-constituted matrices to induce MSC differentiation into the NPC lineage. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Novel Matrices for Differentiation of Human Mesenchymal Stem Cells into Disk Cells
Authors: Schmiermund A. , Gebauer E. , Fuchsbauer H.-L. , Czermak P. , Salzig D. 
Published: June 2012

Introduction Degeneration of the nucleus pulposus (NP), part of the intervertebral disk (IVD), is a major reason for back pain. Stem cell therapy is one approach for treatment. Therefore, it is necessary to differentiate the human mesenchymal stem cells (hMSC) into NP-cells. Differentiation requires a 3D environment in a biocompatible matrix in which the cells were embedded. Beside biocompatibility, pressure resistance is a necessary requirement on the matrices. In vivo the IVD is exposed to pressures up to 3 MPa (30 bar). With regard to minimal invasive treatment of patients later on, the matrices have to be injectable and solidify after injection. In this work, different compositions of potential matrices for the regeneration of the NP were analyzed. hMSC-TERT (- telomerase reverse transcriptase) have been embedded in gelatin and a “gelatin-porcine nucleus pulposus” matrix. The enzyme transglutaminase was found used for cross-linking of the matrices. The results were compared with work previously done on agarose matrix. Materials and Methods Cells were seeded in different matrices at a density of 4 × 106 cells per cm3, equal to the density in the NP. The immobilized cells were cultivated for 21 days in media, containing growth and differentiation factors. Viability of the cells in the different matrices was proofed by using a tetrazolium salt (WST-1). At certain times, RNA isolation was done following the phenol/guanidine isothiocyanate protocol. RNA was transformed into cDNA followed by a RT-PCR. Different primers were used to analyze the differentiation of hMSC-TERT. Results Via WST1-test the survival of hMSC-TERT in gelatine was proofed. The differentiation status of hMSC-TERT in the two different matrices (gelatine, NP extract) was analyzed. The PCR analysis showed a differentiation in a chondrogenic type, less with the NP extract. In agarose a differentiation in a NP cell type could be obtained. Conclusion The results lead to the conclusion that the influence of matrices on cell differentiation is greater than recently surmised. Therefore, it is necessary to find a “close to nature”- matrix for the need in cell therapy. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Does Cervical Disk Arthroplasty Reduce Adjacent Segment Disease and Other Complications in Comparison to Anterior Cervical Discectomy and Fusion? a Meta-Analysis of Randomized Controlled Trials
Authors: Samartzis D. , Vavken P. , Modi H. , Luk K. , Cheung K. 
Published: June 2012

Introduction To reduce the risk of adjacent segment disease and other procedure-related complications following anterior cervical discectomy and fusion (ACDF), cervical disk arthroplasty (CDA) has been advocated for one-level cervical disk disease. However, it remains unknown whether CDA decreases the occurrence of such complications. As such, the following study addressed a meta-analysis of randomized controlled trials assessing the efficacy of CDA in reducing adjacent segment disease and other complications in comparison to ACDF. Materials and Methods Three reviewers performed a literature search for randomized controlled trials comparing CDA to ACDF for radiculopathy and/or myelopathy for one-level cervical disk disease. Studies with 2 years or greater follow-up were selected. Adjacent segment disease, secondary surgery (i.e., revision, reoperation, instrumentation/graft removal), and adverse events were assessed and pooled for analyses. Results Eight studies were included for review. Due to limitations with study design, studies presented with Level II evidence. CDA exhibited a decrease risk for reoperation attributed to adjacent segment disease, but was not statistically significant ( p > 0.05). Additional procedure-related complications did not statistically differ between groups ( p > 0.05). Conclusion Up to 4-year follow-up, CDA does not significantly reduce the risk of adjacent segment disease and other complications in comparison to ACDF. Due to the lack of blinding, variation in surgical management and relatively high withdrawal/drop-out rates among studies at 2 and 4 year follow-up, robust conclusions supporting the advocacy of CDA over ACDF cannot be made at this stage. High-quality studies are needed to properly assess the true efficacy of such interventions. I confirm having declared any potential conflict of interest for all authors listed on this abstract Yes Disclosure of Interest None declared
Almost periodic operators in 𝑉𝑁(𝐺)
Authors: Chou Ching 
Published: June 2012

Let

G
G

be a locally compact group,

A
(
G
)

A(G)

the Fourier algebra of

G
G

,

B
(
G
)

B(G)

the Fourier-Stieltjes algebra of

G
G

and

VN

(
G
)

{\text {VN}}(G)

the von Neumann algebra generated by the left regular representation

λ
\lambda

of

G
G

. Then

A
(
G
)

A(G)

is the predual of

VN

(
G
)

{\text {VN}}(G)

;

VN

(
G
)

{\text {VN}}(G)

is a

B
(
G
)

B(G)

-module and

A
(
G
)

A(G)

is a closed ideal of

B
(
G
)

B(G)

. Let

AP

(

G
^

)
=
{
T
∈

VN

(
G
)
:
u
↦
u
⋅
T

{\text {AP}}(\hat G) = \{ T \in {\text {VN}}(G):u \mapsto u \cdot T

is a compact operator from

A
(
G
)

A(G)

into

VN

(
G
)
}

{\text {VN}}(G)\}

, the space of almost periodic operators in

VN

(
G
)

{\text {VN}}(G)

. Let

C
δ
∗

(
G
)

C_\delta ^*(G)

be the

C
∗

{C^*}

-algebra generated by

{
λ
(
x
)
:
x
∈
G
}

\{ \lambda (x):x \in G\}

. Then

C
δ
∗

(
G
)
⊂

AP

(

G
^

)

C_\delta ^*(G) \subset {\text {AP}}(\hat G)

. For a compact

G
G

, let

E
E

be the rank one operator on

L
2

(
G
)

{L^2}(G)

that sends

h
∈

L
2

(
G
)

h \in {L^2}(G)

to the constant function

∫

h
(
x
)
d
x

\int {h(x)dx}

. We have the following results: (1) There exists a compact group

G
G

such that

E
∈
AP
(

G
^

)
∖

C
δ
∗

(
G
)

E \in \text {AP}(\hat G)\backslash C_\delta ^*(G)

. (2) For a compact Lie group

G
G

,

E
∈

AP(

G
^

)

⇔
E
∈

C
δ
∗

(
G
)
⇔

L
∞

(
G
)

E \in {\text {AP(}}\hat G{\text {)}} \Leftrightarrow E \in C_\delta ^*(G) \Leftrightarrow {L^\infty }(G)

has a unique left invariant mean

⇔
G

\Leftrightarrow G

is semisimple. (3) If

G
G

is an extension of a locally compact abelian group by an amenable discrete group then

AP

(

G
^

)
=

C
δ
∗

(
G
)

{\text {AP}}(\hat G) = C_\delta ^*(G)

. (4) Let

G
=

F

r

G = {{\mathbf {F}}_r}

, the free group with

r
r

generators,

1
>
r
>
∞

1 > r > \infty

. If

T
∈

VN

(
G
)

T \in {\text {VN}}(G)

and

u
↦
u
⋅
T

u \mapsto u \cdot T

is a compact operator from

B
(
G
)

B(G)

into

VN

(
G
)

{\text {VN}}(G)

then

T
∈

C
δ
∗

(
G
)

T \in C_\delta ^*(G)

.
A conformal inequality related to the conditional gauge theorem
Authors: McConnell Terry R. 
Published: June 2012

We prove the inequality

h

(
x

)

−
1

G
(
x
,
y
)
h
(
y
)
⩽
c
G
(
x
,
y
)
+
c

h{(x)^{ - 1}}G(x,y)h(y) \leqslant cG(x,y) + c

, where

G
G

is the Green function of a plane domain

D
,

h

D,\;h

is positive and harmonic on

D
D

, and

c
c

is a constant whose value depends on the topological nature of the domain. In particular, for the class of proper simply connected domains

c
c

may be taken to be an absolute constant. As an application, we prove the Conditional Gauge Theorem for plane domains of finite area for which the constant

c
c

in the above inequality is finite.
An invariant of regular isotopy
Authors: Kauffman Louis H. 
Published: June 2012

This paper studies a two-variable Laurent polynomial invariant of regular isotopy for classical unoriented knots and links. This invariant is denoted

L
K

{L_K}

for a link

K
K

, and it satisfies the axioms: 1. Regularly isotopic links receive the same polynomial. 2.

L

[

unk

]

=
1

{L_{[{\text {unk}}]}} = 1

. 3.

L

[

unk

]

=
a
L
,

L

[

unk

]

=

a

−
1

L

{L_{[{\text {unk}}]}} = aL,\qquad {L_{[{\text {unk}}]}} = {a^{ - 1}}L

. 4.

L

[

unk

]

+

L

[

unk]

=
z
(

L

[

unk]

+

L

[

unk]

)

{L_{[{\text {unk}}]}} + {L_{[{\text {unk]}}}} = z({L_{[{\text {unk]}}}} + {L_{[{\text {unk]}}}})

. Small diagrams indicate otherwise identical parts of larger diagrams. Regular isotopy is the equivalence relation generated by the Reidemeister moves of type II and type III. Invariants of ambient isotopy are obtained from

L
L

by writhe-normalization.
Unusually large gaps between consecutive primes
Authors: Maier Helmut , Pomerance Carl 
Published: June 2012

Let

G
(
x
)

G(x)

denote the largest gap between consecutive primes below

x
x

. In a series of papers from 1935 to 1963, Erdàs, Rankin, and Schànhage showed that
\[

G
(
x
)
≥
(
c
+
o
(
1
)
)

log

x

loglog

x

loglogloglog

x

(

logloglog

x

)

−
2

G(x) \geq (c + o(1)){\operatorname {log}}x{\operatorname {loglog}}x{\operatorname {loglogloglog}}x{({\operatorname {logloglog}}x)^{ - 2}}

\]
, where

c
=

e
γ

c = {e^\gamma }

and

γ
\gamma

is Euler’s constant. Here, this result is shown with

c
=

c
0

e
γ

c = {c_0}{e^\gamma }

where

c
0

=
1.31256
…

{c_0} = 1.31256 \ldots

is the solution of the equation

4

/

c
0

−

e

−
4

/

c
0

=
3

4/{c_0} - {e^{ - 4/{c_0}}} = 3

. The principal new tool used is a result of independent interest, namely, a mean value theorem for generalized twin primes lying in a residue class with a large modulus.
Power series space representations of nuclear Fréchet spaces
Authors: Vogt Dietmar 
Published: June 2012

Let

E
E

be a nuclear graded Fréchet space such that the norms satisfy inequalities

|

|

|

|

k
2

≤

C
k

|

|

|

|

k
−
1

|

|

|

|

k
−
1

||||_k^2 \leq {C_k}|||{|_{k - 1}}|||{|_{k - 1}}

for all

k
k

, let

F
F

be a graded Fréchet space such that the dual (extended real valued) norms satisfy inequalities

|

|

|

|

k

∗
2

≤

D
k

|

|

|

|

k
−
1

∗

|

|

|

|

k
+
1

∗

||||_k^{*2} \leq {D_k}||||_{k - 1}^*||||_{k + 1}^*

for all

k
k

, and let

A
A

be a tame (resp. linearly tame) linear map from

F
F

to

E
E

. Then there exists a tame (resp. linearly tame) factorization of

A
A

through a power series space

Λ
∞
2

(
α
)

\Lambda _\infty ^2(\alpha )

. In the case of a tame quotient map,

E
E

is tamely equivalent to a power series space of infinite type. This applies in particular to the range of a tame (resp. linearly tame) projection in a power series space

Λ
∞
2

(
α
)

\Lambda _\infty ^2(\alpha )

. In this case one does not need nuclearity. It also applies to the tame spaces in the sense of the various implicit function theorems. If they are nuclear, they are tamely equivalent to power series spaces

Λ
∞

(
α
)

{\Lambda _\infty }(\alpha )

.