bluuebunny/crossref_metadata_2025 huggingface dataset:
Helmet rental practices at United States ski areas: a national survey
Authors: Clingenpeel J M , Marshall S W
Published: December 2003

Objectives:Studies have shown that head injuries are the leading cause of death on ski slopes. Statistics on helmet rental practices at ski areas across the United States have never been reported. This study sought to determine the prevalence of United States ski areas offering helmet rental during the 2002–03 ski season. Secondarily it sought to analyze the relationships of geographic region and size of ski area with helmet rental availability and to gather information on ski helmet rental cost to the consumer.

Methods and setting:A stratified cross sectional telephone survey of a sample of 331 United States ski area onsite rental shops during February 2003.

Results:Altogether 50% of ski areas offered helmet rental with significant variation in the prevalence of helmet rental among ski areas of differing regions and sizes (p<0.01). A majority of Northeastern (57%), Western (63%), and Rocky Mountain (71%) ski areas rented helmets, whereas a minority of Southern (37%) and Midwestern (23%) ski areas rented helmets. Twenty five percent of the smallest ski areas (⩽50 acres) rented helmets compared with 74% of the largest ski areas (⩾501 acres).

Conclusions:United States ski area helmet rental practices vary by region of the country and ski area size. Winter sports participants interested in wearing protective headgear should be aware of the helmet rental practices at the ski area in which they plan to visit and consider helmet purchase if they visit mainly smaller ski areas or areas within the South or Midwest.
Examining child restraint use and barriers to their use: lessons from a pilot study
Authors: Simpson J C , Wren J , Chalmers D J , Stephenson S C R
Published: December 2003

Objective:To determine the suitability of four research methods to measure the rate of child restraint device (CRD) use and incorrect use in New Zealand and obtain data on barriers to CRD use.

Design and setting:To assess the rates of CRD use among vehicles carrying children 8 years of age and under, two methods were piloted—namely, an unobtrusive observational survey and a short interview and close inspection. A self administered questionnaire and focus group interviews were also piloted to assess CRD use, reasons for use and non-use, and to obtain information on barriers to their use. Respondents to all methods except the focus groups were approached in supermarket car park sites at randomly selected times. Focus groups were established with parents identified through early childhood organisations. All methods were assessed on criteria related to efficiency, representativeness, and ability to obtain the necessary data.

Results:The observational survey provided a simple method for identifying rates of CRD use, while the self administered questionnaire obtained data on demographic characteristics and reported the installation and use/non-use of CRDs. The interview/inspection addressed all the questions of both the above methods and enabled incorrect CRD use to be examined. The focus groups provided the most meaningful information of all methods on barriers to CRD use.

Discussion and conclusion:Advantages and limitations of these methods are discussed and some refinements of the original instruments are proposed. The interview/inspection and focus group methods were identified as being more appropriate for efficiently obtaining reliable data on CRD use and identification of barriers to CRD use.
Being “at fault” in traffic crashes: does alcohol, cannabis, cocaine, or polydrug abuse make a difference?
Authors: Chipman M L , Macdonald S , Mann R E
Published: December 2003

Objective:To compare associations of alcohol, cannabis, and cocaine abuse and traffic crash risk for “at fault” crashes and all crashes.

Design:A historical cohort study.

Setting:Toronto, Ontario.

Patients or subjects:Subjects beginning treatment at the Centre for Addictions and Mental Health (CAMH) in 1994 for abuse of alcohol, cannabis, cocaine, and all combinations of these substances (n = 590, with 411 drivers). A control group consisted of 518 records from the Ontario registry of registered drivers, frequency matched for age and sex and residence.

Interventions:CAMH subjects took part in therapeutic programs. Pre-intervention (11 115 driver-years) and post-intervention intervals (8550 driver-years) were defined and compared.

Main outcome measures:Crash and collision rates, adjusted relative risks (ARRs) of crash involvement and of “at fault” crashes were computed using Poisson regression to control for variations in time at risk, age, and sex of participants.

Results:Pre-treatment, significant ARRs of 1.49 to 1.79 for all crashes were found for abusers of cannabis, cocaine, or a combination. ARRs increased by 10%–15% for “at fault” crashes. Post-treatment, all associations were very modest for all abuse types. Only younger and male drivers had a significantly increased risk, which was stronger for “at fault” than for all crashes.

Conclusions:Abuse of cannabis and cocaine pre-treatment was more strongly related to “at fault” crashes than to all crashes. Interaction between these substances means that the effects of combined abuse cannot be predicted from simple main effects.
Evaluation of the ThinkFirst Canada,Smart Hockey, brain and spinal cord injury prevention video
Authors: Cook D J , Cusimano M D , Tator C H , Chipman M L
Published: December 2003

Objective:The ThinkFirst CanadaSmart Hockeyprogram is an educational injury prevention video that teaches the mechanisms, consequences, and prevention of brain and spinal cord injury in ice hockey. This study evaluates knowledge transfer and behavioural outcomes in 11–12 year old hockey players who viewed the video.

Design:Randomized controlled design.

Setting:Greater Toronto Minor Hockey League, Toronto Ontario.

Subjects:Minor, competitive 11–12 year old male ice hockey players and hockey team coaches.

Interventions:TheSmart Hockeyvideo was shown to experimental teams at mid-season. An interview was conducted with coaches to understand reasons to accept or refuse the injury prevention video.

Main outcome measures:A test of concussion knowledge was administered before, immediately after, and three months after exposure to the video. The incidence of aggressive penalties was measured before and after viewing the video.

Results:The number of causes and mechanisms of concussion named by players increased from 1.13 to 2.47 and from 0.67 to 1.22 respectively. This effect was maintained at three months. There was no significant change in control teams. There was no significant change in total penalties after video exposure; however, specific body checking related penalties were significantly reduced in the experimental group.

Conclusion:This study showed some improvements in knowledge and behaviours after a single viewing of a video; however, these findings require confirmation with a larger sample to understand the sociobehavioural aspects of sport that determine the effectiveness and acceptance of injury prevention interventions.
Shall-issue policy and criminal activity among applicants for permits to carry concealed firearms
Authors: Romero M , Wintemute G , Wright M , Parham C
Published: December 2003

Permits to carry concealed firearms in public (CCW permits) remain controversial. A small scale natural experiment with shall-issue CCW permit policy in California, a may-issue state, is reported. During the mid-1990s, the chief of police of the Sacramento County town of Isleton issued permits to all county residents who applied and passed a standard background check. This program received national publicity. The incidence of subsequent criminal activity among 691 persons applying for CCW permits through Isleton’s program in 1995 and that in a statewide sample of 965 CCW applicants from 1993–94 were compared. Subjects were followed up for three years from their application dates. The arrest rates for violent crime among Isleton and statewide applicants were 291 and 104 per 100 000 person-years, respectively (relative risk 2.8, 95% confidence interval 0.7 to 11.2, p = 0.18). This suggests that a shall-issue policy for CCW permits may result in higher rates of violent crime among permit holders, but the results do not reach statistical significance; larger studies are needed.
Reporting of the incidence of hospitalised injuries: numerator issues
Authors: Boufous S , Williamson A
Published: December 2003

Objectives:To examine and discuss the implications on the incidence of hospitalised injuries of selecting cases from principal diagnosis field only compared with considering all diagnosis fields, the inclusion compared with the exclusion of medical injuries, and the impact of identifying multiple admissions.

Methods:Analysis of data from the 1999–2000 New South Wales Inpatient Statistics Collection, Australia, including an internal linkage of the same dataset.

Results:Approximately 27.5% of records with a non-injury primary diagnosis include a nature of injury diagnosis in a subsequent diagnostic field. This figure increased to more than half (53%) of discharges for medical injuries. The internal linkage showed that 6.5% of discharges were repeat admissions for the sameInternational Classification of Diseases, 10th revision (ICD-10) injury code and that 13.8% were repeat admissions for any ICD-10 injury code. The proportions of repeat admissions varied according to the type and the mechanism of injury.

Conclusions:Selecting hospitalised injury cases from the principal diagnosis alone would underestimate medical injury cases as well as other injuries occurring in hospital. Repeat admissions should always be considered particularly in the case of thermal injuries, self harm, and medical injuries. Due to the limitations of data linkage, alternative methods need to be developed to identify repeat admissions. Other areas in which further research would be beneficial to a more uniform reporting of injury hospitalisations include better identification of injuries occurring in hospital, a review of ICD-10 injury codes, and the development an ICD-10 based severity measure which can be readily used with hospital discharge data.
Comparison of Substance P Concentration in Acupuncture Points in Different Tissues in Dogs
Authors: Chang W.W. , Weissensteiner H. , Rausch W.D. , Chen K.Y. , Wu L.S. , Lin J.H.
Published: December 2003

Histologically, acupuncture points show neuronal innervation. One hundred seventy-seven tissue samples of acupuncture points and control points from 4 dogs were collected. Concentrations of substance P, a neurotransmitter, in the skin, muscle and subcutis of acupuncture points and control points were measured by means of enzyme immunoassay. The determined tissue concentrations of substance P (mean ± SEM) in a acupuncture points and control points were 1.81 ± 0.13 and 1.51 ± 0.1 ng/g in the muscle, 3.33 ± 0.29 and 2.63 ± 0.28 ng/g in the skin and 1.59 ± 0.22 and 1.32 ± 0.16 ng/g in the subcutis, respectively. The results indicate that there is a difference in the neurochemical profile between acupuncture points and control points.
Effects of Moxibustion on the Enhancement of Serum Antibody in Rabbit againstStaphylococcus aureus
Authors: Yamashita Hitoshi , Ichiman Yoshitoshi , Takahashi Masami , Nishijo Kazushi
Published: December 2003

The titer and activity of antibody in rabbits immunized with heat-killed vaccine were assessed with and without moxibustion treatment. Enzyme-linked immunosorbent assay (ELISA) was applied for the detection of immunoglobulins to Smith strain of Staphylococcus aureus. Positive IgM titer of more than 0.4 were observed with this assay against the moxibustion group (P < 0.05). The titer of IgG antibody also increased; however, there was no significant difference between the moxibustion group and the control group. The ELISA inhibition test showed significantly higher protective activity of the sera in the moxibustion group at the 9th week after the first immunization (P < 0.05).
Absence of an Analgesic Effect of Qigong "External Qi" in Rats
Authors: Zhang Wen-Bin , Yu Wei-Lin , Yang Yuan-Jing
Published: December 2003

The analgesic effect of "external Qi" emitted from the Qigong practitioner was investigated in rats. In behavioral experiments, the rat's tail-flick and head-movement threshold measurements were used to determine if the "external Qi" had analgesic effect. The Results were negative. In electro-physiological study, the "external Qi" shows no significant changes in the pain-related evoked cortical potentials to tooth-pulp stimulation. Thus the results of this study are different from those reported by other investigators. It is proposed that this research be repeated and extended.
Liu-Wei-Dihuang: A Study by Pulse Analysis
Authors: Wang Wei Kung , Hsu Tse Lin , Wang Yuh Yin Lin
Published: December 2003

Pulse analysis method was used in studying the traditional Chinese formula Liu-Wei-Dihuang as well as five of its main components (Rehmannia glutinosa, Comus officinalis, Paeonia Suffruticosa, Poria cocos and Alisma plantogo-aquatica var oriental). Based on our recently developed resonance theory, we tried to elucidate the mechanism and mutual reactions of these meridian related herbs. Hot water herbal extracts were injected intraperitoneally into rats and the pressure pulse spectrum at the caudate artery was measured. The results of this study indicated that Liu-Wei-Dihuang mildly increased blood flow to meridians with lower resonance frequency: namely the liver C1, the kidney C2 and the spleen C3; but decreased blood flow to the higher resonance frequency organs and meridians: the lung C4, the stomach C5, the gall bladder C6, and the bladder C7. It also decreased the heart load C0. All of the five herb components increased blood flow to the kidney C2 and the spleen C3; but their effects on the high frequency organs varied. Alisma plantogo-aquatica val. oriental decreased the C0, C5, C6, C7; Poria cocos decreased C1, C4, C5, C6;. Rehmannia glutinosa, Paeonia Suffruticosa decreased C0, C4, C5, C6, C7; Comus officinalis increased C4 but decreased C0, C5. C6, C7.
A Protein-bound Polysaccharide Synergistic with Lipopolysaccharide Induces Nitric Oxide Release and Antioxidant Enzyme Activities in Mouse Peritoneal Macrophages
Authors: Pang Zhan-Jun , Zhou Mei , Chen Yuan , Wan Jennifer
Published: December 2003

The aim of this study is to examine whether polysaccharide krestin, a protein-bound polysaccharide, can prevent the progression of therosclerosis and lipoperoxidative injury caused by oxidatively modified low density lipoprotein (Ox-LDL) to macrophages. The alterations of GSHPx (glutathione peroxidase), SOD (superoxide dismutase) activity and NO (nitric oxide) release in PSK-treated mouse peritoneal macrophages, and the effect of LPS on them were investigated. With peritoneal injection of PSK, the following were observed in the mouse peritoneal macrophages: 1) an increase in SeGSHPx activity, 2) elevation in non-SeGSHPx and SOD activity; 3) the enzyme activities were further improved by addition of lipopolysaccharide (LPS); and 4) much NO was found to be released by PSK-treated mouse peritoneal macrophages stimulated by LPS.
HLA and HPA Typing in Idiopathic Thrombocytopenic Purpura Patients Treated with Kami-kihi-to
Authors: Matsuzaki Tatsunori , Nomura Shosaku , Yamaoka Manabu , Ozaki Yoshio , Yoshimura Chie , Xie Gui Lan , Katsura Kaoruko , Kagawa Hideo , Ishida Tomoko , Fukuhara Shirou
Published: December 2003

We performed human leukocyte antigen (HLA) and human platelet antigen (HPA) in patients with Kami-kihi-to-responsive idiopathic thrombocytopenic purpura. The HLA-A2, A61 and Cw1 were significantly increased in responders compared with nonresponders, as were HLA DRB 1 *0901, DRB 1 *1502, and DPB 1 *0501. In contrast, HLA DPB 1 *0201 and DPB 1 *0901 were significantly decreased in responders. The a/b genotype of HPA-2 and a/a genotype of HPA-3 were markedly increased in nonresponders, and anti-GPIb antibody was also increased. These results suggest that HLA, HPA, and anti-GP antibody studies may predict the response of idiopathic thrombocytopenic purpura to Kami-kihi-to.
The Correlation between Skin Electrical Conductance and the Score of Qi Vacuity
Authors: Yu Hsi-Ming , Chang Hen-Hong , Liou Shaw-Yih , Li Shu-Fang , Hou Ming-Mou , Chen Ming-Feng
Published: December 2003

In traditional Chinese medicine, the syndrome of qi vacuity means that the patient's body has a low level of energy to react to stress. Recently, we used a score, the QV score, by scaling the severity of symptoms and signs of qi vacuity in patients with tiredness. The aim of this study was to investigate the relationship between QV score and skin electrical conductance in patients with tiredness. One hundred and forty-three healthy controls and 103 patients with tiredness were involved. Each subject received a weak electrical stimulation with constant voltage (1.75 volt), and conductance was measured between two different limbs. The mean value of skin conductance among four limbs was calculated and expressed by a special unit, namely Chin. The correlation between the skin conductance and QV score was analyzed by a linear regression analysis. The results showed that skin electrical conductance of healthy controls was negatively correlated with age (r-coefficient = -0.511, P = 0.000). The skin conductance of patients with tiredness was significantly lower than that of healthy controls with matching age (P = 0.000 by Student's t-test). Moreover, there was a positive correlation between the decrease of skin conductance and the QV score in patients with tiredness (r-coefficient = - 0.68, P = 0.000). These results suggest that a decrease in skin electrical conductance may be closely related to the severity of qi vacuity. The skin conductance test is a simple, reliable, and quantitative method for detection of syndrome of qi vacuity.
The Effects of Ginseng Radix Rubra on Human Vascular Endothelial Cells
Authors: Nakajima Shigekatsu , Uchiyama Yasuhiko , Yoshida Kazuo , Mizukawa Hiromi , Haruki Eiichi
Published: December 2003

The effect of Ginseng Radix Rubra (Red ginseng) on human vascular endothelial cells was examined. Red ginseng was found to promote the proliferation of vascular endothelial cells, inhibit the production but promote the decomposition of endothelin, which is known to constrict blood vessels and raise blood pressure as well as accelerate the synthesis of nitric oxide. which is known to have an angio-tonic effect. Furthermore, Red ginseng was observed to increase the production of Interleukin 1ß, which is known to play important roles in the homeostatic activities of the human body such as immunity and inflammation as well as increasing the production of tissue plasminogen activators, which suppress the formation of thrombin in the blood coagulation and fibrinolysis mechanisms. It is suggested that Red ginseng has the effect of accelerating endothelial cells proliferation and of promoting physiological activities.
Classical brackets for dissipative systems
Authors: Bimonte Giuseppe , Esposito Giampiero , Marmo Giuseppe , Stornaiolo Cosimo
Published: December 2003

We show how to write a set of brackets for the Langevin equation, describing the dissipative motion of a classical particle, subject to external random forces. The method does not rely on an action principle, and is based solely on the phenomenological description of the dissipative dynamics as given by the Langevin equation. The general expression for the brackets satisfied by the coordinates, as well as by the external random forces, at different times, is determined, and it turns out that they all satisfy the Jacobi identity. Upon quantization, these classical brackets are found to coincide with the commutation rules for the quantum Langevin equation, that have been obtained in the past, by appealing to microscopic conservative quantum models for the friction mechanism.
NON-COMMUTATIVE COMPLEX PROJECTIVE SPACES AND THE STANDARD MODEL
Authors: DOLAN BRIAN P.
Published: December 2003

The standard model fermion spectrum, including a right handed neutrino, can be obtained as a zero-mode of the Dirac operator on a space which is the product of complex projective spaces of complex dimension two and three. The construction requires the introduction of topologically non-trivial background gauge fields. By borrowing from ideas in Connes' non-commutative geometry and making the complex spaces 'fuzzy' a matrix approximation to the fuzzy space allows for three generations to emerge. The generations are associated with three copies of space-time. Higgs' fields and Yukawa couplings can be accommodated in the usual way.
A Theory Of Errors in Quantum Measurement
Authors: Rajeev S. G.
Published: December 2003

It is common to model the random errors in a classical measurement by the normal (Gaussian) distribution, because of the central limit theorem. In the quantum theory, the analogous hypothesis is that the matrix elements of the error in an observable are distributed normally. We obtain the probability distribution this implies for the outcome of a measurement, exactly for the case of traceless 2 × 2 matrices and in the steepest descent approximation in general. Due to the phenomenon of 'level repulsion', the probability distributions obtained are quite different from the Gaussian.
BIOMECHANICAL EFFECT OF THORACIC POSTERIOR VERTEBRAL ELEMENTS ON PATTERNS OF THE LOCI OF INSTANTANEOUS AXES OF ROTATION IN SAGITTAL PLANE
Authors: Teo Ee-Chon , Qiu Tian-Xia , Yang Kai , Ng Hong-Wan , Lee Kim-Kheng
Published: December 2003

The objective of this study was to investigate the effect of the thoracic posterior vertebral elements on the kinematics of T10–T11 motion segment in sagittal plane by assessing the locations and loci of the instantaneous axes of rotation (IARs) under flexion and extension pure moments using finite element (FE) method. The IAR has proven to be a useful parameter of vertebral motion and it is an indicator of spinal instability.

An anatomically accurate FE model of thoracic T10–T11 functional spinal unit (FSU) was used to characterize the loci of centers of rotation for the intact T10–T11 FSU and disc body unit (without posterior vertebral elements) under flexion and extension pure moments. The centers of rotation predicted by the intact model and disc body unit of thoracic T10–T11 for both flexion and extension were directly below the geometrical center of the moving vertebra. However, the loci of the IARs were significantly affected by the posterior vertebral elements. The loci of instantaneous axes of rotation for the intact model were tracked superoanteriorly and inferoposteriorly for flexion and extension with rotation, respectively. While, for the disc body unit, the loci were detected to diverge lateroinferiorly from the mid-height of the intervertebral disc, they converge medio-inferiorly toward the superior endplate of the inferior vertebra T11 with increased moment. These findings may offer an insight to better understanding the kinematics of the human thoracic spine and provide clinically relevant information for the evaluation of spinal stability and implant devices functionality.
On some properties of ⊕‐supplemented modules
Authors: Idelhadj A. , Tribak R.
Published: December 2003

A module M is ⊕‐supplemented if every submodule of M has a supplement which is a direct summand of M. In this paper, we show that a quotient of a ⊕‐supplemented module is not in general ⊕‐supplemented. We prove that over a commutative ring R, every finitely generated ⊕‐supplemented R‐module M having dual Goldie dimension less than or equal to three is a direct sum of local modules. It is also shown that a ring R is semisimple if and only if the class of ⊕‐supplemented R‐modules coincides with the class of injective R‐modules. The structure of ⊕‐supplemented modules over a commutative principal ideal ring is completely determined.
Extensions of rational modules
Authors: Cuadra J.
Published: December 2003

For a coalgebra C, the rational functor is a left exact preradical whose associated linear topology is the family ℱC, consisting of all closed and cofinite right ideals of C∗. It was proved by Radford (1973) that if C is right ℱ‐Noetherian (which means that every I ∈ ℱC is finitely generated), then Rat (−) is a radical. We show that the
converse follows if C1, the second term of the coradical
filtration, is right ℱ‐Noetherian. This is a consequence of our main result on ℱ‐Noetherian coalgebras which states that the following assertions
are equivalent: (i) C is right ℱ‐Noetherian; (ii) Cn is right ℱ‐Noetherian for all n ∈ ℕ; and (iii) ℱC is closed under products and C1 is right ℱ‐Noetherian. New examples of right ℱ‐Noetherian coalgebras are provided.
On the resolvent of an ideal and some applications
Authors: Bouziane Driss , Rody Abdelilah Kandri
Published: December 2003

We give an algorithm to compute a resolvent of an algebraic
variety without computing its irreducible components; we decompose
the radical of an ideal into prime ideals and we test the
primality of a regular ideal.
Eight‐dimensional real absolute‐valued algebras with left unit whose automorphism group is trivial
Authors: Rochdi A.
Published: December 2003

We classify, by means of the orthogonal group 𝒪7(ℝ), all eight‐dimensional real absolute‐valued
algebras with left unit, and we solve the isomorphism problem. We
give an example of those algebras which contain no
four‐dimensional subalgebras and characterise with the use of the
automorphism group those algebras which contain one.
Flat covers of representations of the quiver A∞
Authors: Enochs E. , Estrada S. , Rozas J. R. García , Oyonarte L.
Published: December 2003

Rooted quivers are quivers that do not contain
A∞ ≡ ⋯→•→• as a subquiver. The existence of flat covers and cotorsion envelopes
for representations of these quivers have been studied by Enochs et al. The main goal of this paper is to prove that flat covers and cotorsion envelopes exist for
representations of A∞. We first characterize finitely generated projective representations of A∞. We also see that there are no
projective covers for representations of A∞, which adds more
interest to the problem of the existence of flat covers.
On chains of centered valuations
Authors: Chibloun Rachid
Published: December 2003

We study chains of centered valuations of a domain A and chains of centered valuations of A [X1, …, Xn] corresponding to valuations of A. Finally, we make some applications to chains of valuations centered on the same ideal of A [X1, …, Xn] and extending the same valuation of A.
Graded transcendental extensions of graded fields
Authors: Boulagouaz M.
Published: December 2003

We study transcendency properties for graded field extension and
give an application to valued field extensions.
Modular representations of Loewy length two
Authors: Charkani M. E. , Bouhamidi S.
Published: December 2003

Let G be a finite p‐group, K a field of characteristic p, and J the radical of the group algebra K[G]. We study modular representations using some new results of
the theory of extensions of modules. More precisely, we describe the K[G]‐modules M such that J2M = 0 and give some
properties and isomorphism invariants which allow us to compute
the number of isomorphism classes of K[G]‐modules M such
that dimK(M) = μ(M) + 1, where μ(M) is the minimum
number of generators of the K[G]‐module M. We also compute
the number of isomorphism classes of indecomposable
K[G]‐modules M such that dimK(Rad(M)) = 1.
Quadratic pairs in characteristic 2 and the Witt cancellation theorem
Authors: Elomary Mohamed Abdou
Published: December 2003

We define the orthogonal sum of quadratic pairs and we show that there is no Witt cancellation theorem for this operation in characteristic 2.
Twistings, crossed coproducts, and Hopf‐Galois coextensions
Authors: Caenepeel S. , Wang Dingguo , Wang Yanxin
Published: December 2003

Let H be a Hopf algebra. Ju and Cai (2000) introduced the
notion of twisting of an H‐module coalgebra. In this paper, we
study the relationship between twistings, crossed coproducts, and
Hopf‐Galois coextensions. In particular, we show that a twisting
of an H‐Galois coextension remains H‐Galois if the twisting
is invertible.
Association of the Human Y Chromosome with Cholesterol Levels in the General Population
Authors: Charchar Fadi J. , Tomaszewski Maciej , Lacka Beata , Zakrzewski Jaroslaw , Zukowska-Szczechowska Ewa , Grzeszczak Wladyslaw , Dominiczak Anna F.
Published: December 2003

Objective—

Males are at higher risk of cardiovascular diseases than females. The aim of the study was to test whether the potential of the Y chromosome to affect cardiovascular risk could be attributed to its influence on lipids.

Methods and Results—

1288 Polish men (1157 subjects from young healthy cohort and 131 individuals from middle-aged hypertensive population) were phenotyped for determinants of cardiovascular risk including BMI, blood pressures, lipids, and testosterone. Each subject was genotyped for the
Hin
dIII(+/−) polymorphism within the nonrecombining region of the Y chromosome. Men with the
Hin
dIII(−) variant exhibited significantly higher total cholesterol (TC) and low-density lipoprotein cholesterol (LDL) levels than subjects with the
Hin
dIII(+) genotype in both populations. The differences between the genotypes were 0.15 mmol/L (
P
=0.0107) and 0.45 mmol/L (
P
=0.0377) in TC and 0.15 mmol/L (
P
=0.0059) and 0.41 mmol/L (
P
=0.0432) in LDL among young apparently healthy men and middle-aged hypertensive men, respectively. The
Hin
dIII(+) was associated with a significant increase in blood pressure of the middle-aged men. Testosterone serum concentrations correlated positively with HDL-cholesterol levels, and this association was independent of the Y chromosome.

Conclusions—

The results indicate that a locus/loci on the Y chromosome may influence LDL levels, independent of testosterone levels.
Incidence of Fatal or Repaired Abdominal Aortic Aneurysm in Relation to Inflammation-Sensitive Plasma Proteins
Authors: Engström Gunnar , Börner Gabriel , Lindblad Bengt , Janzon Lars , Lindgärde Folke
Published: December 2003

Background—

Inflammation is an important pathophysiological feature of abdominal aortic aneurysms (AAA). Whether elevated levels of inflammation-sensitive plasma proteins (ISPs) predict the long-term risk of fatal or repaired AAA is largely unknown.

Methods and Results—

Five ISPs (fibrinogen, orosomucoid, α1-antitrypsin, haptoglobin, and ceruloplasmin) were measured in 6075 healthy men, mean age 46.8±3.7 years. After a mean time of 19 years, 63 men had a fatal or surgically/endovascularly repaired AAA. Risk of treatment or death from future AAA was studied in relation to the ISPs. The risk of future AAA increased significantly with the number of elevated ISPs (ie, in the top quartile). The proportions with future AAA were 0.4%, 1.0%, 1.3%, and 2.3% for men with none, one, two, and ≥3 ISPs, respectively, in the top quartile (trend:
P
<0.0001). The corresponding odds ratios were 1.00 (reference), 1.9 (95% CI: 0.8 to 4.5), 2.2 (0.9 to 5.5), and 3.2 (1.4 to 7.2), respectively, adjusted for age, screening year, smoking, cholesterol, triglycerides, systolic blood pressure and physical inactivity (trend:
P
=0.004).

Conclusion—

The incidence of fatal or repaired AAA is associated with the ISP levels. In this population-based study, elevated ISPs could be observed many years before the clinical manifestation of disease.
Adenoviral Transfer of Endothelial Nitric Oxide Synthase Attenuates Lesion Formation in a Novel Murine Model of Postangioplasty Restenosis
Authors: von der Thüsen Jan H. , Fekkes Madelon L. , Passier Robert , van Zonneveld A.J. , Mainfroid V. , van Berkel Theo J.C. , Biessen Erik A.L.
Published: December 2003

Objective—

Restenosis remains a major late complication of percutaneous transluminal coronary angioplasty (PTCA), for which the development of prevention strategies has thus far been hampered by the lack of a representative and practical animal model. We have, therefore, developed a murine model of PTCA-induced restenosis.

Methods and Results—

Rigid probe angioplasty of pre-existing atherosclerotic lesions in the carotid arteries of ApoE-deficient mice was found to result in an increase in lesion size (0.14±0.04×10
5
μm
2
to 0.42±0.09×10
5
μm
2
,
P
=0.007) with a smooth muscle cell-rich, fibrotic lesion morphology. In an additional experiment, lesions were incubated immediately after angioplasty with adenovirus bearing an endothelial nitric oxide synthase (eNOS) transgene (Ad.APT.eNOS), or an “empty” control virus (Ad.APT.empty) at a titer of 1.5×10
9
pfu/mL. Ad.APT.eNOS treatment was seen to lead to a 73.1% reduction in plaque size (0.27±0.04×10
5
μm
2
versus 1.02±0.39×10
5
μm
2
,
P
=0.07), which translated to a significantly lowered average degree of stenosis (33.6±4.1% versus 74.6±14.0%,
P
=0.02). Ad.APT.eNOS also decreased lesional collagen content from 29.1% to 4.8% (
P
<0.001).

Conclusion—

We believe that we have established a representative murine model of postangioplasty restenosis, which may serve to elucidate the mechanisms underlying restenosis and to evaluate potential antirestenotic therapies.
Physical Training Increases Endothelial Progenitor Cells, Inhibits Neointima Formation, and Enhances Angiogenesis
Authors: Laufs Ulrich , Werner Nikos , Link Andreas , Endres Matthias , Wassmann Sven , Jürgens Kristina , Miche Eckart , Böhm Michael , Nickenig Georg
Published: December 2003

Background—

The molecular mechanisms by which physical training improves peripheral and coronary artery disease are poorly understood. Bone marrow–derived endothelial progenitor cells (EPCs) are thought to exert beneficial effects on atherosclerosis, angiogenesis, and vascular repair.

Methods and Results—

To study the effect of physical activity on the bone marrow, EPCs were quantified by fluorescence-activated cell sorter analysis in mice randomized to running wheels (5.1±0.8 km/d, n=12 to 16 per group) or no running wheel. Numbers of EPCs circulating in the peripheral blood of trained mice were enhanced to 267±19%, 289±22%, and 280±25% of control levels after 7, 14, and 28 days, respectively, accompanied by a similar increase of EPCs in the bone marrow and EPCs expanded from spleen-derived mononuclear cells. eNOS
−/−
mice and wild-type mice treated with
N
G
-nitro-
l
-arginine methyl ester showed lower EPC numbers at baseline and a significantly attenuated increase of EPC in response to physical activity. Exercise NO dependently increased serum levels of vascular endothelial growth factor and reduced the rate of apoptosis in spleen-derived EPCs. Running inhibited neointima formation after carotid artery injury by 22±2%. Neoangiogenesis, as assessed in a subcutaneous disc model, was increased by 41±16% compared with controls. In patients with stable coronary artery disease (n=19), moderate exercise training for 28 days led to a significant increase in circulating EPCs and reduced EPC apoptosis.

Conclusions—

Physical activity increases the production and circulating numbers of EPCs via a partially NO-dependent, antiapoptotic effect that could potentially underlie exercise-related beneficial effects on cardiovascular diseases.
Stabilization of Atherosclerotic Plaques by Blockade of Macrophage Migration Inhibitory Factor After Vascular Injury in Apolipoprotein E–Deficient Mice
Authors: Schober Andreas , Bernhagen Jürgen , Thiele Michael , Zeiffer Ute , Knarren Sandra , Roller Marion , Bucala Richard , Weber Christian
Published: December 2003

Background—

Macrophage migration inhibitory factor (MIF), a cytokine that controls cell-mediated inflammatory responses, is upregulated in atherogenesis; however, its functional contribution to lesion development has not been evaluated.

Methods and Results—

We studied the role of MIF on neointima lesion formation after wire-induced injury of carotid arteries in apolipoprotein E–deficient (apoE
−/−
) mice. Immunohistochemistry revealed that MIF expression was detectable in endothelial cells before injury and upregulated in smooth muscle cells (SMCs) 24 hours after endothelial denudation. Three weeks after injury, MIF was predominantly found in endothelial cells and macrophage-derived foam cells. Neutralizing MIF with a monoclonal antibody resulted in a marked reduction of neointimal macrophages and inhibited transformation of macrophages into foam cells. Conversely, the content of SMCs and of collagen in the neointima were increased, amounting to a slight but not significant reduction in neointima and media size after 3 weeks of MIF monoclonal antibody treatment. Notably, serum levels of the cytokines IL-2, IL-4, IL-6, IL-10, and tumor necrosis factor were increased in MIF monoclonal antibody–treated mice. In vitro flow assays revealed that MIF pretreatment of aortic endothelium enhanced monocyte recruitment and that the monocyte arrest induced by oxidized LDL is mediated by endothelial MIF, as shown by monoclonal antibody inhibition.

Conclusions—

Inhibition of MIF resulted in a shift in the cellular composition of neointimal plaques toward a stabilized phenotype with reduced macrophage/foam cell content and increased SMC content. This might be attributable to a reduction of monocyte recruitment mediated by endothelial MIF.
Unusual Effects of a QT-Prolonging Drug, Arsenic Trioxide, on Cardiac Potassium Currents
Authors: Drolet Benoit , Simard Chantale , Roden Dan M.
Published: December 2003

Background—

Cases of QT prolongation, torsades de pointes, and sudden death have been reported with arsenic trioxide (As
2
O
3
), a highly effective agent for acute promyelocytic leukemia. In this study, we evaluated the effects of As
2
O
3
on repolarizing cardiac ion currents.

Methods and Results—

In HERG- or KCNQ1+KCNE1-transfected CHO cells (n=32; total), As
2
O
3
caused concentration-dependent block of both
I
Kr
and
I
Ks
, with an IC
50
for tail current block of 0.14±0.01 μmol/L for
I
Kr
and 1.13±0.06 μmol/L for
I
Ks
. In contrast to other QT-prolonging drugs, As
2
O
3
also activated a time-independent current that additional experiments identified as
I
K-ATP
.

Conclusions—

As
2
O
3
blocks both
I
Kr
and
I
Ks
at clinically relevant concentrations. On the other hand, it also activates
I
K-ATP
, which maintains normal repolarization. We infer that variability in the extent of QT interval prolongation and onset of ventricular arrhythmias during arsenic therapy represents competing effects to block and activate multiple repolarizing potassium currents.
Pressure-Independent Effects of Angiotensin II on Hypertensive Myocardial Fibrosis
Authors: Tokuda Keisuke , Kai Hisashi , Kuwahara Fumitaka , Yasukawa Hideo , Tahara Nobuhiro , Kudo Hiroshi , Takemiya Kiyoko , Koga Mitsuhisa , Yamamoto Tomoka , Imaizumi Tsutomu
Published: December 2003

Angiotensin II (Ang II) is implicated in the proinflammatory process in various disease situations. Thus, we sought to determine the role of Ang II in early inflammation-induced fibrosis of pressure-overloaded (PO) hearts. PO was induced by suprarenal aortic constriction (AC) at day 0 in male Wistar rats, and they were orally administered 0.1 mg/kg per day candesartan every day from day −7. This was the maximum dose of candesartan that did not change arterial pressure in hypertensive rats with AC (AC rats). In AC rats, cardiac angiotensin-converting enzyme (ACE) activity was transiently enhanced after day 1 and peaked at day 3, declining to lower levels by day 14, whereas serum ACE activity was not changed. In AC rats, PO induced early fibroinflammatory changes (monocyte chemoattractant factor [MCP]-1 and transforming growth factor [TGF]-β expression, perivascular macrophage accumulation, and fibroblast proliferation), and thereafter, left ventricular hypertrophy developed, featuring myocyte hypertrophy, intramyocardial arterial wall thickening, and perivascular and interstitial fibroses. Candesartan suppressed the induction of MCP-1 and TGF-β and reduced macrophage accumulation and fibroblast proliferation in PO hearts. Candesartan significantly prevented perivascular and interstitial fibrosis. However, candesartan did not affect myocyte hypertrophy and arterial wall thickening. In conclusion, a subdepressor dose of candesartan prevented the MCP-1–mediated inflammatory process and reactive myocardial fibrosis in PO hearts. Ang II might play a key role in reactive fibrosis in hypertensive hearts, independent of arterial pressure changes.
Heparan Sulfate Proteoglycans Function as Receptors for Fibroblast Growth Factor-2 Activation of Extracellular Signal–Regulated Kinases 1 and 2
Authors: Chua Ceres C. , Rahimi Nader , Forsten-Williams Kimberly , Nugent Matthew A.
Published: December 2003

Fibroblast growth factor-2 (FGF2) activates the extracellular signal–regulated kinases 1 and 2 (ERK1/2) through its specific receptors. Interaction of FGF2 with cell-surface heparan sulfate proteoglycans has also been suggested to induce intracellular signals. Thus, we investigated whether FGF2 can stimulate ERK1/2 activation through heparan sulfate proteoglycans using mechanisms that do not depend on receptor activation in vascular smooth muscle cells. The activation of FGF receptors was inhibited by treating cells with 5′-deoxy-5′methyl-thioadenosine and by expressing truncated dominant-negative FGF receptors. In both cases, FGF2 was able to stimulate the phosphorylation of ERK1/2 despite the absence of detectable FGF receptor tyrosine kinase activity. The FGF2 activation of ERK1/2 in the absence of receptor activity was completely dependent on heparan sulfate, because this activity was abolished by heparinase III digestion of the cells. In contrast, heparinase III treatment of control cells, with functional FGF receptors, showed only slight changes in FGF2-mediated ERK1/2 activation kinetics. Thus, in addition to serving as coreceptors for FGF receptor activation, heparan sulfate proteoglycans might also function directly as receptors for FGF2-induced ERK1/2 activation. Activation of ERK1/2 via cell-surface proteoglycans could have significant biological consequences, potentially directing cell response toward growth, migration, or differentiation.
PPARα Activators Inhibit Vascular Endothelial Growth Factor Receptor-2 Expression by Repressing Sp1-Dependent DNA Binding and Transactivation
Authors: Meissner Markus , Stein Monika , Urbich Carmen , Reisinger Kerstin , Suske Guntram , Staels Bart , Kaufmann Roland , Gille Jens
Published: December 2003

Peroxisome proliferator–activated receptors (PPARs) are ligand-activated transcription factors, originally implicated in the regulation of lipid and glucose homeostasis. In addition, natural and synthetic PPAR activators may control inflammatory processes by inhibition of distinct proinflammatory genes. As signaling via the vascular endothelial growth factor receptor-2 (VEGFR2) pathway is critical for angiogenic responses during chronic inflammation, we explored whether known antiinflammatory effects of PPAR ligands are mediated in part through diminished VEGFR2 expression. In this study, PPARα agonists are found to inhibit endothelial VEGFR2 expression, whereas predominant PPARγ ligands remained without discernible effects. Time- and concentration-dependent inhibition is demonstrated both at the level of protein and mRNA VEGFR2 expression. Inhibitory effects of PPARα agonists on transcriptional activity of the VEGFR2 promoter are conveyed by an element located between base pairs −60 and −37 that contains two adjacent consensus Sp1 transcription factor binding sites. Constitutive Sp1-containing complex formation to this sequence is decreased by PPARα treatment, indicating that VEGFR2 gene expression is inhibited by repressing Sp1 site-dependent DNA binding and transactivation. Our coimmunoprecipitation experiments revealed enhanced protein interactions between PPARα and Sp1 on PPARα activation, thus constituting a probable mechanism by which PPARα activators decrease Sp-dependent binding activity to the VEGFR2 promoter. Hence, molecular mechanisms by which PPARs modulate the rate of gene transcription may include direct interactions between specific transcription factors and PPARs that ultimately result in reduced DNA binding to their respective response elements.
Long-Term Ambulatory Monitoring for Cerebral Emboli Using Transcranial Doppler Ultrasound
Authors: Mackinnon Andrew D. , Aaslid Rune , Markus Hugh S.
Published: December 2003

Background and Purpose—

Transcranial Doppler (TCD) monitoring for asymptomatic cerebral emboli is currently limited to short recordings by equipment size, restricting its clinical usefulness. We have developed a first ambulatory TCD system, evaluated it in at-risk patient groups, and used it to study the pattern of embolization in patients with symptomatic carotid stenosis.

Methods—

The system comprises an 18×11.5×3.2 cm battery-powered Doppler unit (425 g) and a 13-mm servo-controlled 2 MHz transducer probe. The quadrature raw Doppler signal is stored on flash-disk. An autosearch algorithm restores vessel insonation should signal quality fall. Initial evaluation was in 20 ambulatory stroke patients. Subsequently, 12 recently symptomatic carotid patients had recordings for ≥5 hours.

Results—

Recordings were well tolerated and a median of 96% of Doppler signal was suitable for analysis. Embolic signals were detected in 11 of the 12 symptomatic carotid patients. There was marked temporal variability in embolization and prolonging the recording increased the yield of embolic signal positive patients from 58% at 30 minutes to 92% at 150 minutes. In 3 subjects with frequent embolic signals, significant temporal clustering of embolic signals was observed.

Conclusions—

We have developed the first ambulatory TCD system. Good-quality recordings of ≥5 hours can be obtained. In view of the demonstrated temporal variability in embolization, this technique is likely to improve the predictive value of recording for asymptomatic embolic signals and may be particularly useful in patients in whom embolic signals are relatively infrequent, such as those with asymptomatic carotid stenosis and atrial fibrillation.
Rats, Communications, and Plague: Toward an Ecological History
Authors: McCormick Michael
Published: December 2003

During the last twenty years, archaeozoological research has significantly transformed the picture of the black rat (rattus rattus) in classical antiquity and medieval Europe. These new data, in conjunction with extant texts from these periods, make a great contribution to the understanding of the bubonic plagues of the sixth and the fourteenth centuries, as well as to the history of the communications and economic systems linking the Mediterranean to the Indian Ocean and the Atlantic. The study of ancient rats and their colonization extends the temporal and geographical groundwork for a fully historical global ecology.
“We've Got a Right to Fight; We're Married”: Domestic Homicide in Chicago, 1875–1920
Authors: Adler Jeffrey S.
Published: December 2003

Scholars often treat family violence as a single category and argue that domestic violence typically reflects conflict over gender roles. Such a focus has been well placed. But if data on domestic homicide in Chicago from 1875 to 1920 are disaggregated by ethnicity and race, important patterns emerge. Domestic homicide, for example, assumed culturally specific forms. German immigrants, Italian immigrants, and African-American Chicagoans killed loved ones for different reasons, at different rates, and with different family members involved. Although the violence revolved around challenges to gender identity and expectations, each group defined such challenges in distinct ways, reflecting a complex blend of cultural assumptions and material circumstances.
Quid nobis cum pelago? The New Thalassology and the Economic History of Europe
Authors: Peters Edward
Published: December 2003

The long debate about the nature and decline of the ancient Mediterranean economy and the appearance of a distinctive northern European economy has been considerably enriched by recent research in archaeology, ecology, numismatics, and communications history. Particularly striking has been the expansion of research into untraditional areas—microregional histories of the Mediterranean, hagiography, and the evidence of physical mobility. The result of this expansion has been to redefine the problem of the ancient and the later economies and to suggest new methods for continuing research.