Creation of quasi-Dirac points in the Floquet band structure of bilayer graphene.

We study the Floquet quasi-energy band structure of bilayer graphene when it is illuminated by two laser lights with frequencies [Formula: see text] and [Formula: see text] using Floquet theory. We focus on the dynamical gap formed by the conduction band with Floquet index = -1 and the valence band with Floquet index = +1 to understand how Dirac points can be formed. It is found that the dynamical gap does not have rotation symmetry in the momentum space, and quasi-Dirac points, where the conduction and valence bands almost touch, can be created when the dynamical gap closes along some directions with suitably chosen radiation parameters. We derive analytical expressions for the direction dependence of the dynamical gaps using Lowdin perturbation theory to gain a better understanding of the formation of quasi-Dirac points. When both radiations are circularly polarized, the gap can be exactly zero along some directions, when only the first and second order perturbations are considered. Higher order perturbations can open a very small gap in this case. When both radiations are linearly polarized, the gap can be exactly zero up to the fourth order perturbation and more than one quasi-Dirac point is formed. We also study the electron velocity around a dynamical gap and show that the magnitude of the velocity drops to values close to zero when the k vector is near to the gap minimum. The direction of the velocity also changes around the gap minimum, and when the gap is larger in value the change in the velocity direction is more gradual. The warping effect does not affect the formation of a Dirac point along the k x axis, while it prevents its formation when there is phase shift between the two radiations.

Psychosomatic and physical responses to a multi-component stress management program among teaching professionals: A randomized study of cognitive behavioral intervention (CB) with complementary and alternative medicine (CAM) approach.

BACKGROUND: The present study aims to assess psychosomatic and physical responses to a multi-component stress management program with the use of CAM and CB approaches among teaching professionals in Hong Kong. METHOD: A random controlled trial (RCT) was used to compare between CB group (n = 26) and the CAM-CB group (n = 30). Interventions were administered for 1.5 h once a week for eight consecutive weeks. A self-administered questionnaire including perceived stress scale (PSS) and frequency of psychosomatic symptoms were measured at baseline (T1), immediate after the program (T2), and 4 weeks after the program (T3). Physical parameters were measured at T1 and T2. RESULTS: A reduction of 23% in PSS was observed in the CB group, while the CAM-CB group yielded 18% reductions in PSS from T1 to T3 [F(2,108) = 3.099; p = .049]. No significant interactions were observed in the frequency of psychosomatic symptoms and physical parameters. However, a significant downward time trend was observed (p < .001) and larger percentage changes in physical responses were shown in the CAM-CB group than CB group. CONCLUSION: Clinical evidence of both the CAM-CB and CB program has been demonstrated in the current study and both approaches are easy to be self-implemented. The CAM technique might serve as an alternative choice for self-administered stress management to replace the additional time needed for professional follow-up contacts. It might further improve some physical responses such as handgrip strength and resting heart rate, which are associated with better psychosomatic health and better occupational stress management.

Effects of acupressure on anxiety: a systematic review and meta-analysis.

OBJECTIVE: To evaluate the evidence from randomised controlled trials (RCTs) and quantify the effects of acupressure on anxiety among adults. METHODOLOGY: RCTs published between January 1997 and February 2014, comparing acupressure with sham control, were identified from the databases Science Citation Index/Social Sciences Citation Index, Scopus, PubMed and PsycINFO. Meta-analysis of eligible studies was performed and the magnitude of the overall effect size was calculated for the anxiety outcome. Revised STRICTA (the Standards for Reporting Interventions in Clinical Trials of Acupuncture) criteria were used to appraise the acupressure procedures, and the Cochrane risk of bias tool was used to assess the methodological quality of the studies. RESULTS: Of 39 potentially relevant studies, seven RCTs met the inclusion criteria for review while five studies met the criteria for meta-analysis. All studies reported the positive effect of acupressure on relieving anxiety from the anticipation of surgery or treatment. EX-HN3 (Yintang), HT7 (Shenmen) were the commonest points selected and two studies used bilateral points. The acupressure procedure was generally well reported and studies had a low risk of bias. The combined results of the five trials showed a greater overall reduction in anxiety in the acupressure group than in the sham controls (standardised mean differences (SMD)=-1.11; 95% CI -1.61 to -0.61; p<0.0001 heterogeneity: I(2)=75%; χ(2)=16.17; p=0.003; r=0.485). CONCLUSIONS: Acupressure seems to be effective in providing immediate relief of pretreatment anxiety among adults, and has a medium effect size. However, conflicting results were found for the improvements on physiological indicators. More rigorous reporting, including allocation concealment procedure, is needed to strengthen the results.

A pilot evaluation on a stress management programme using a combined approach of cognitive behavioural therapy (CBT) and complementary and alternative medicine (CAM) for elementary school teachers.

The aim of this study is to explore the efficacy of implementing a stress management programme based on a combined approach using cognitive behavioural therapy and complementary and alternative medicine for elementary school teachers who experienced mild level of stress, anxiety and/or depressive symptoms in Hong Kong. A 12-h programme involving cognitive behavioural therapy, self-management, relaxation techniques (diaphragmatic breathing and progressive muscle relaxation), mindful exercises (qigong and yoga), aromatherapy and acupressure was conducted. A quasi-experimental design was used to compare the intervention groups (n = 47) with the wait-list control groups (n = 46). The primary outcome measures were depression, anxiety and stress. Results indicated that the intervention group had significant reduction in depression [(F = 3.93; degrees of freedom (df) = 2.90; p = 0.023)], anxiety (F = 3.37; df = 2.90; p = 0.039) and stress (F = 3.63; df = 2.89; p = 0.031) when compared with the control group. Participants in both groups demonstrated lowered level of salivary cortisol at the post-assessment. The pilot results provided preliminary support to the multi-component stress management programme in relieving affective symptoms of teachers. The programme may be considered as an initial strategy to empower teachers with the abilities to cope with their affective symptoms. Further evaluation using a better designed randomized study with a larger sample size is warranted. (word: 198; max.: 200).

The retained placenta: historical and geographical rate variations.

In this study, we sought to explore the variation in reported rates of retained placenta around the world and over time in the UK. A systematic review of observational studies was performed to obtain retained placenta rates from around the world and annual hospital reports from the Royal College of Obstetricians and Gynaecologists archives were examined to obtain historical retained placenta rates. The data show that the median rate of retained placenta at 30 minutes was higher in developed countries (2.67% vs 1.46%, p < 0.02), as was the median manual removal rate (2.24% vs 0.45%, p < 0.001). In addition to this, there appears to have been a rise in rate of manual removal in the UK from a mean of 0.66% in the 1920s to 2.34% in the 1980s (p < 0.0001).

A systematic review on the anxiolytic effects of aromatherapy in people with anxiety symptoms.

PURPOSE: We reviewed studies from 1990 to 2010 on using aromatherapy for people with anxiety or anxiety symptoms and examined their clinical effects. METHODS: The review was conducted on available electronic databases to extract journal articles that evaluated the anxiolytic effects of aromatherapy for people with anxiety symptoms. RESULTS: The results were based on 16 randomized controlled trials examining the anxiolytic effects of aromatherapy among people with anxiety symptoms. Most of the studies indicated positive effects to quell anxiety. No adverse events were reported. CONCLUSIONS: It is recommended that aromatherapy could be applied as a complementary therapy for people with anxiety symptoms. Further studies with better quality on methodology should be conducted to identify its clinical effects and the underlying biologic mechanisms.

Three year follow-up study of an integrated supported employment for individuals with severe mental illness.

OBJECTIVES: The aim of the present study was to examine and compare the long-term effectiveness of the Integrated Supported Employment (ISE) programme, which consists of individual placement and support (IPS) and work-related social skills training, with the IPS programme on the vocational and non-vocational outcomes among individuals with severe mental illness (SMI) over a period of 3 years. METHOD: One hundred and eighty-nine participants with SMI were recruited from two non-government organizations and three day hospitals in Hong Kong and randomly assigned into the ISE (n = 58), IPS (n = 65) and traditional vocational rehabilitation (TVR) (n = 66) groups. Vocational and non-vocational outcomes of the ISE and IPS participants were collected by a blind and independent assessor at 7 11, 15, 21, 27, 33 and 39 months after their admission, whereas the TVR groups were assessed only up to the 15th month follow up. RESULTS: After 39 months of service provision, ISE participants obtained higher employment rate (82.8% vs 61.5%) and longer job tenure (46.94 weeks vs 36.17 weeks) than the IPS participants. Only 6.1% of TVR participants were able to obtain employment before the 15th month follow up. Fewer interpersonal conflicts at the workplace were reported for the ISE participants. Advantages of the ISE participants over IPS participants on non-vocational outcomes were not conclusive. CONCLUSION: The long-term effectiveness of the ISE programme in enhancing employment rates and job tenures among individuals with SMI was demonstrated by this randomized controlled trial.

Effects of mindful and non-mindful exercises on people with depression: a systematic review.

PURPOSE: An emerging body of evidence has shown the therapeutic effect of both mindful and non-mindful physical exercises on the treatment of depression. The purpose of this study is to examine the effectiveness of mindful and non-mindful physical exercises as an intervention in managing depression or depressive symptoms based on a systematic literature review. METHODS: Our review was conducted among five electronic databases to identify randomized controlled trials (RCTs), which tested the effects of mindful or/and non-mindful physical exercises on depression. Studies were classified according to the baseline depression status of participants and its relation to allocation concealment, blinding at outcome assessment, follow-up, and whether intention to treat analysis was employed. RESULTS: The results based on 12 RCTs indicated that both the mindful and non-mindful physical exercises were effective in their short-term effect in reducing depression levels or depressive symptoms. However, most of studies had methodological problems that only small sample size was used, and the maintenance effects of physical exercise were not reported. Specific comparisons between RCTs on mindful and non-mindful exercises were not performed because of the limitations on the designs. CONCLUSIONS: We recommend that more well-controlled studies have to be conducted in the future to address the short- and long-term effects of physical exercise on alleviating depression. Efforts should be focused on unveiling the differential effects of mindful and non-mindful exercises on depression and the underlying mechanisms of their therapeutic action.

A family with osteoporosis pseudoglioma syndrome due to compound heterozygosity of two novel mutations in the LRP5 gene.

Osteoporosis pseudoglioma syndrome (OPPG) is an autosomal recessive disorder due to mutations in the low-density lipoprotein receptor-related protein 5 (LRP5) gene. Here, we report two novel missense mutations found in a southern Chinese family of a non-consanguineous marriage. Three out of four children had blindness, low bone mineral density (BMD) and multiple fractures in their childhood. Genotyping by DNA sequencing demonstrated 2 new mutations in exon 7 of the LRP5 gene. Tryptophans at amino acid residue positions 478 and 504 were replaced by arginine (W478R) and cysteine (W504C), respectively. While the parents that possessed either heterozygous W478R or W504C were apparently normal, all affected subjects were compound heterozygotes for the W478R and W504C mutations in the LRP5 gene. W478R is located immediately C-terminal to the third YWTD repeat of the second YWTD/EGF domain in LRP5, while W504C is located between the third and the fourth YWTD repeats of the second YWTD/EGF domain in LRP5. Using LRP5-related proteins, such as the low-density lipoprotein receptor (LDLR) and nidogen as reference models, a homology model of LRP5 suggested that the observed mutations may affect the molecular interactions of LRP5 and so lead to the observed OPPG phenotypes.

Dimethyl sulfoxide as an inducer of differentiation in preosteoblast MC3T3-E1 cells.

Osteoblastic differentiation is an essential part of bone formation. Dimethyl sulfoxide (DMSO) is a water miscible solvent that is used extensively for receptor ligands in osteoblast studies. However, little is known about its effects on osteoblastogenic precursor cells. In this study, we have used a murine preosteoblast cell line MC3T3-E1 cells to demonstrate that DMSO effectively induces osteoblastic differentiation of MC3T3-E1 cells via the activation of Runx2 and osterix and is dependent upon the protein kinase C (PKC) pathways. We further demonstrated that prolonged activation of PKC pathways is sufficient to induce osteoblastic differentiation, possibly via the activation of PKD/PKCmu.

Sources of burdens on families of individuals with mental illness.

Families of individuals with mental illness face a range of practical and emotional stresses. Studies that have addressed the sources of these burdens are limited. Literature suggests that burdens could come from the stigmatizing attitudes towards individuals with mental illness and inadequate public resources. Nevertheless, how public attitudes and availability of public resources have affected the burden on patients' families remains to be studied. This study set out to explore the relationship between stigma, accessibility of mental health facilities and family burden through individual interviews of patients' relatives in order to understand the burden on mentally ill patients' relatives from their perspectives. Ten interviewees from two out-patient psychiatric clinics were recruited and interviewed. Each interviewee had at least one family member receiving out-patient psychiatric services. Altogether 11 mentally ill patients were involved. Data analyses showed that much of the burden was related to stigma and to lack of mental health and rehabilitation services. Consequences included social isolation of the families, difficulties experienced by the mentally ill patients when trying to obtain competitive employment and financial difficulties. Subjective burden resulting from social stigma included frustration, anxiety, low self-esteem and helplessness. Implications of the findings to social policy and development of mental health services were discussed.

Induction of Tie-1 and Tie-2 receptor protein expression after cerebral ischemia-reperfusion.

Tie-1 and Tie-2 are receptor tyrosine kinases (RTKs) that are exclusively expressed in endothelial cells and play important roles in endothelial cell biology. The authors have reported previously the temporal profiles of Tie-1 and Tie-2 mRNA expression after focal cerebral ischemia-reperfusion. In the current study, the localization of Tie-1/Tie-2 mRNA and proteins were further investigated in the same focal ischemia model. In situ hybridization showed that, after 60-minute ischemia and 72-hour reperfusion, both Tie-1 and Tie-2 mRNA appeared as capillary-like structures in the ischemic middle cerebral artery (MCA) cortex. Western blot analysis showed a biphasic expression of Tie-1 protein in the same region. The first peak, spanning the ischemic and early reperfusion period. was of low intensity and short-lived. The second peak was of greater intensity and spanning the period from 72 to 168 hours after reperfusion. Similarly, Tie-2 expression at the protein level also exhibited a biphasic pattern. Immunohistochemical studies, after 72 hours of reperfusion, showed that although Tie-1 and Tie-2 were detected within the ischemic cortex, they actually were expressed in different populations of endothelial cells in different regions. In agreement with the in situ hybridization study, Tie-1 immunoreactivity appeared as capillary-like structures in cortical layers 2 to 4. Similar capillary-like appearance of Tie-2 immunoreactivity was noted in the outer cortical layers. In addition, Tie-2 immunoreactivity also was observed in cortical layer 6b, where de novo large vessel formation was noted. Cellular colocalization experiments revealed that Tie-2 is expressed in proximity to its antagonist, Angpo-2, as well as basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) in cortical layer 1, where active vessel remodeling was noted. Interestingly, bFGF only partially colocalized with VEGF, suggesting differential roles for these angiogenic factors during vessel remodeling. Tie-1 protein, to a lesser degree, also colocalized with Angpo-2, bFGF, and VEGF in cortical layer 1. Magnetic resonance imaging (MRI) showed increased regional cerebral blood flow (CBF) corresponding to the expression of these angiogenesis gene products. Together, these findings suggest that the evolving expression of angiogenesis genes underlie the robust vascular remodeling after ischemia and reperfusion.

Cloning and expression of a novel nuclear matrix-associated protein that is regulated during the retinoic acid-induced neuronal differentiation.

Retinoic acid (RA), a derivative of vitamin A, is essential for the normal patterning and neurogenesis during development. RA treatment induces growth arrest and terminal differentiation of a human embryonal carcinoma cell line (NT2) into postmitotic central nervous system neurons. Using RNA fingerprinting by arbitrarily primed polymerase chain reaction, we identified a novel serine/threonine-rich protein, RA-regulated nuclear matrix-associated protein (Ramp), that was down-regulated during the RA-induced differentiation of NT2 cells. Prominent mRNA expression of ramp could be detected in adult placenta and testis as well as in all human fetal tissues examined. The genomic clone of ramp has been mapped to the telomere of chromosome arm 1q, corresponding to band 1q32.1-32.2. Associated with the nuclear matrix of NT2 cells, Ramp translocates from the interphase nucleus to the metaphase cytoplasm during mitosis. During the late stage of cytokinesis, Ramp concentrates at the midzone of the dividing daughter cells. The transcript expression of ramp is closely correlated with the cell proliferation rate of NT2 cells. Moreover, overexpression of Ramp induces a transient increase in the proliferation rate of NT2 cells. Taken together, our data suggest that Ramp plays a role in the proliferation of the human embryonal carcinoma cells.

Induction of angiogenesis related genes in the contralateral cortex with a rat three-vessel occlusion model.

The bFGF/FGFR, VEGF/VEGFR and Angiopoietin/Tie receptor system are crucial for angiogenesis and vascular remodeling. With a rat focal cerebral ischemia model, we previously reported dramatic changes in the vascular density and angiogenesis related genes in the ipsilateral cortex after 60 minutes severe ischemia. While only a small increase in the capillary density was noted in the contralateral cortex with very mild ischemia. In the present study we further reported that only Tie-1 and VEGFR-2 mRNA were significantly changed in the contralateral cortex with a p value of 0.0001 and 0.0168, respectively, and the degree of changes were very small. Interestingly, in contrast to a huge increase in the ipsilateral cortex, Tie-1 mRNA was slowly decreased after the onset of ischemia and stayed below the basal level throughout the remaining periods studied. The mechanism and significance for this decrease is not presently clear. In contrast to the ipsilateral cortex, the Angpo-1/Angpo-2 mRNA ratio was also slightly dropped below the basal level in the contralateral side in most of the ischemia-reperfusion periods studied, which is in line with the notion that small decrease in Angpo-1/Angpo-2 mRNA ratio implied small vascular remodeling activity. It is very likely that increase in this Angpo-1/Angpo-2 ratio is crucial for remodeling into large vessels and increase in Tie-1 may be crucial for capillary density increasing. Nevertheless, the detailed mechanisms and significance of differential expression of these genes and relationship to vascular remodeling remain to be characterized.

Ganoderma extract activates MAP kinases and induces the neuronal differentiation of rat pheochromocytoma PC12 cells.

The pharmacology and clinical application of traditional Chinese medicine has been extensively documented. We have used an in vitro model system, PC12 cells, to demonstrate the presence of neuroactive compounds in Ganoderma lucidum (lingzhi). Ganoderma extract induced the neuronal differentiation of PC12 cells and prevented nerve growth factor-dependent PC12 neurons from apoptosis. Moreover, these effects of ganoderma might be mediated via the ras/extracellular signal-regulated kinase (Erk) and cAMP-response element binding protein (CREB) signaling pathways, as demonstrated by the phosphorylation of Erk1, Erk2 and CREB. Thus, our data not only present the first evidence of the presence of neuroactive compounds that mediate the neuronal differentiation and neuroprotection of the PC12 cells, but also reveal the potential signaling molecules involved in its action.

Identification and characterization of differentially expressed genes in denervated muscle.

Denervation results in a series of changes in skeletal muscle. To elucidate the molecular basis underlying these changes, it is important to identify the profile of altered gene expression in skeletal muscle following nerve injury. In the present study, we have examined the differentially expressed genes in denervated gastrocnemius muscle using RNA fingerprinting by arbitrarily primed PCR. Eight differentially expressed mRNA transcripts have been identified. A bilateral regulatory profile can be observed for the up-regulated genes in both denervated and contralateral control muscle following unilateral sciatic nerve injury. The temporal expression profiles of the denervation-regulated genes in muscle during development, together with their dependency on nerve activity, suggest potential functional roles following nerve injury in vivo. In particular, the identification of two apoptosis-related genes in denervated muscle provides molecular evidence that the apoptotic process is likely to be involved in the intricate changes that lead to muscle atrophy. Our findings not only allow the identification of novel genes, but also suggest possible functions for some known genes in muscle following nerve injury. Taken together, these findings provide important insights into our understanding of the molecular events in denervated muscle and suggest that the differentially expressed genes may play potential roles during muscle denervation and regeneration.

Expression of retinoid receptors during the retinoic acid-induced neuronal differentiation of human embryonal carcinoma cells.

Retinoic acid (RA), a derivative of vitamin A, is essential for normal patterning and neurogenesis during development. Until recently, studies have been focused on the physiological roles of RA receptors (RARs), one of the two types of nuclear receptors, whereas the functions of the other nuclear receptors, retinoid X receptors (RXRs), have not been explored. Accumulating evidence now suggests that RXRalpha is a critical receptor component mediating the effects of RA during embryonic development. In this study, we have examined the expression profiles of RXRalpha and RARs during the RA-induced neuronal differentiation in a human embryonal carcinoma cell line, NT2. Distinct expression profiles of RXRalpha, RARalpha, RARbeta, and RARgamma were observed following treatment with RA. In particular, we found that RA treatment resulted in a biphasic up-regulation of RXRalpha expression in NT2 cells. The induced RXRalpha was found to bind specifically to the retinoid X response element based on gel mobility retardation assays. Furthermore, immunocytochemical analysis revealed that RXRalpha expression could be localized to the somatoaxonal regions of the NT2 neurons, including the tyrosine hydroxylase- and vasoactive intestinal peptide-positive neurons. Taken together, our findings provide the first demonstration of the cellular localization and regulation of RXRalpha expression in NT2 cells and suggest that RXRalpha might play a crucial role in the cellular functions of human CNS neurons.

Induction of angiopoietin and Tie receptor mRNA expression after cerebral ischemia-reperfusion.

The angiopoietin/Tie receptor system may contribute to angiogenesis and vascular remodeling by mediating interactions of endothelial cells with smooth muscle cells and pericytes. The temporal expression of angiopoietin-1 (Angpo-1), angiopoietin-2 (Angpo-2), Tie-1, and Tie-2 mRNA was studied in a focal cerebral ischemia model in rats. The cDNA fragments obtained from reverse transcription polymerase chain reaction amplification were cloned and used as a probe to detect individual genes. Northern blot analysis showed a delayed increase of a 4.4-kb Angpo-1 transcript for up to 2 weeks after ischemia, eightfold higher than the values of the sham-operated controls. A biphasic expression of a 2.4-kb Angpo-2 transcript was noted, peaking at 24 hours (6.4-fold) and 2 weeks (4.6-fold) after ischemia. The expression of Tie-2 mRNA (4.3 kb), a receptor for Angpo-1, and Tie-1 mRNA (4.3 kb) also increased starting 24 hours after reperfusion and remained elevated for up to 2 weeks after ischemia. The temporal profiles of the expression of these genes were different from those of other angiogenic genes such as basic fibrobast growth factor/fibroblast growth factor receptor and vascular endothelial growth factor/vascular endothelial growth factor receptor and proteolytic enzymes (tissue-type plasminogen activator and urokinase plasminogen activator) and their inhibitors (plasminogen activator inhibitor-1). The expression patterns of these genes could be related to progressive tissue liquefaction and neovascularization after ischemia in this stroke model. Differential expression of these angiogenesis genes suggests the involvement of complex regulatory mechanisms that remain to be characterized.

Altered vascular injury responses in mice deficient in protease-activated receptor-1.

Expression of protease-activated receptor-1 (PAR-1), a cell-surface receptor for thrombin, is increased in balloon-injured rat carotid artery and human atherosclerotic tissue. To examine the role of PAR-1 in vascular injury, we compared vascular injury responses in wild-type (WT) and PAR-1-deficient (PAR-1(-/-)) mice. Arterial injury was induced by inserting a flexible guidewire into the common carotid artery and withdrawing it 6 times with rotation. Bromodeoxyuridine, delivered subcutaneously by osmotic minipump, was used to measure cellular proliferation. Mice were perfusion-fixed at 1, 2, 5, 10, and 14 days after injury. Extensive endothelial damage, mural thrombosis, platelet adherence, and medial smooth muscle cell loss and necrosis were apparent at day 1 in both WT and PAR-1(-/-) mice. The incidence of thrombosis or platelet deposition in WT and PAR-1(-/-) mice declined from 100% at day 1 to 25% and 21%, respectively, at 14 days. Endothelial disruption, as assessed by Evan's blue uptake, was maximum at day 1 and declined by day 14. This apparent endothelial regrowth was similar in WT and PAR-1(-/-) mice. Significant medial thickening at 14 days after injury was similar in WT (from 22.8+/-1.7 to 30.7+/-1.9 microm) and PAR-1(-/-) (from 23.2+/-2.1 to 30.5+/-2.2 microm) mice. Medial area also increased in response to injury but to a lesser extent in PAR-1(-/-) mice (from 0.0250+/-0.0044 to 0.0312+/-0.0047 mm(2)) than in WT mice (from 0.0266+/-0.0040 to 0.0398+/-0.0050 mm(2)). Neointima was variable and occurred in 6 of 13 WT and 5 of 12 PAR-1(-/-) mice. However, intimal area tended to be less in PAR-1(-/-) mice (0. 0016+/-0.0007 mm(2)) compared with WT mice (0.0082+/-0.0032 mm(2)), although this difference did not achieve statistical significance (P=0.06). Cell density was significantly greater in normal carotids from PAR-1(-/-) (6.4+/-0.5 x 10(3)/mm(2)) compared with WT (4.3+/-0. 8 x 10(3)/mm(2)) mice and remained elevated after injury. Vessel and lumen diameters tended to increase in WT mice after injury, whereas vessel diameter was unchanged and lumen diameter actually decreased in PAR-1(-/-) mice. Cell proliferation in injured carotid arteries was similar in PAR-1(-/-) and WT mice. These data suggest that PAR-1(-/-) may play a role in vascular injury responses in this mouse model via possible effects on extracellular matrix regulation.