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1.
Med J Malaysia ; 79(Suppl 1): 140-147, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38555899

ABSTRACT

INTRODUCTION: Vision screening has been initiated to detect potential vision problems, paving referral pathways towards a full eye examination. Time-cost-labour practicality challenges of equipment-based vision screening have lingered for decades. Going for the highest sensitivity and specificity or opting for a pragmatic and affordable vision screening program remains a dilemma in public eye health. We aimed to report the development of a new online and equipment-free vision screening called Eye: Questionnairebased Vision Screening (EyeQVS). We also analysed the visual profile of Orang Bateq resided in a remote locality, using findings from EyeQVS, single test vision screening and full eye examination. MATERIALS AND METHODS: Multi-perspective development strategies were employed in designing EyeQVS. The questionnaire items were constructed using the working backward technique, compiling common vision disorders from the literature and face validation using expert panels. Face validation and usability assessment were performed on EyeQVS. The vision screening was carried out using EyeQVS and single test visual acuity screening method. The full eye examination included visual acuity, refraction, binocular vision and ocular health assessment. The visual profile of indigenous people (Orang Bateq) at Kampung Bengoi and Kampung Atok, Jerantut, Pahang was analysed using EyeQVS, single test visual acuity screening method and full eye examination. RESULTS: The performance of EyeQVS was affirmative in both face validation and usability. About 95% of Orang Bateq failed full eye examination, while 55% failed EyeQVS screening. None of them failed single test vision screening. Binocular disorders and dry eye problems were commonly found in Orang Bateq. EyeQVS unearthed more various vision problems compared to the single test vision screening (visual acuity alone) as a screening tool in a remote location. CONCLUSION: EyeQVS can screen for binocular disorders and dry eyes problem commonly found among indigenous people, which might be missed using a single-test visual acuity screening approach. EyeQVS is a practical alternative for vision screening in places where financial or location hinders eye healthcare access.


Subject(s)
Vision Screening , Humans , Vision Screening/methods , User-Computer Interface , Vision Disorders , Visual Acuity , Mass Screening
2.
Occup Med (Lond) ; 73(7): 391-397, 2023 Oct 20.
Article in English | MEDLINE | ID: mdl-37682842

ABSTRACT

BACKGROUND: Hearing loss leads to increased irritability and disengagement in social activities and conversations, which may impact quality of life. Dental professionals are at risk of developing hearing loss through daily exposure to noise from a wide range of equipment that produces significantly high decibels and noise frequencies. AIMS: The aim of this systematic review was to investigate the risk of hearing loss in dental professionals, including dentists, dental specialists, dental hygienists and dental assistants. METHODS: This review was conducted following the Cochrane Handbook for Systematic Reviews. PubMed, Scopus, Embase, Cochrane, Science Direct, Google Scholar and ProQuest were searched up to March 2023. Seventeen of 416 studies met the inclusion criteria. Quality assessment was performed according to the Newcastle-Ottawa Scale for cohort and case-control studies, and a modified version of this tool for cross-sectional studies. RESULTS: The majority of included studies (82%) found a positive association with hearing loss for dentists and dental specialists, with years of clinical experience identified as a prominent risk factor. Dental hygienists and dental assistants were less commonly reported in the literature. Difference between the left and right ears was found in 71% of studies, with the left ear more affected in both dentists and dental assistants due to proximity to the noise-inducing equipment. CONCLUSIONS: Dental professionals are at risk of hearing loss in their workplace, especially linked to years of clinical experience, which highlights the need for prevention and appropriate ear-protective devices.

3.
Science ; 372(6541): 508-511, 2021 04 30.
Article in English | MEDLINE | ID: mdl-33858990

ABSTRACT

Improving materials used to make qubits is crucial to further progress in quantum information processing. Of particular interest are semiconductor-superconductor heterostructures that are expected to form the basis of topological quantum computing. We grew semiconductor indium antimonide nanowires that were coated with shells of tin of uniform thickness. No interdiffusion was observed at the interface between Sn and InSb. Tunnel junctions were prepared by in situ shadowing. Despite the lack of lattice matching between Sn and InSb, a 15-nanometer-thick shell of tin was found to induce a hard superconducting gap, with superconductivity persisting in magnetic field up to 4 teslas. A small island of Sn-InSb exhibits the two-electron charging effect. These findings suggest a less restrictive approach to fabricating superconducting and topological quantum circuits.

4.
Br J Surg ; 106(9): 1197-1203, 2019 08.
Article in English | MEDLINE | ID: mdl-31210362

ABSTRACT

BACKGROUND: International guidelines on clinical staging of gastric cancer recommend the use of chest CT for the detection of pulmonary metastases. This study assessed the clinical value of routine chest CT in the staging of gastric cancer. METHODS: This retrospective study included patients identified from the gastric cancer registry of Chang Gung Memorial Hospital, Linkou, Taiwan. All patients who underwent clinical staging between 2008 and 2014 were included. The pattern, site and number of metastases at initial presentation and after surgery with curative intent were evaluated. Pulmonary metastases were defined as multiple small round pulmonary nodules with a random distribution or of variable size. RESULTS: Some 1669 patients were included, of whom 478 (28·6 per cent) had metastatic disease at clinical presentation. The majority of metastases were to the peritoneum (75·7 per cent of patients) or liver (30·5 per cent), and only 27 patients (5·6 per cent) had pulmonary metastases at presentation, none of which were isolated to the lung. Of these 27 patients, 11 had primary lesions located at the cardia/fundus. In 19 patients the lung metastases were also detected on the staging chest X-ray. After surgery there were 196 cancer recurrences. Some 15 patients (7·6 per cent) had lung metastasis and this was not the only site of metastases in any patient. The prevalence of lung metastasis at presentation of the disease and after surgery was 1·6 and 1·5 per cent respectively. CONCLUSION: This study does not support the routine use of chest CT for staging of gastric cancer as isolated pulmonary metastasis in the absence of other metastatic sites could not be detected.


Subject(s)
Neoplasm Staging/methods , Stomach Neoplasms/diagnostic imaging , Aged , Female , Humans , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/secondary , Lung Neoplasms/diagnostic imaging , Lung Neoplasms/secondary , Male , Middle Aged , Peritoneal Neoplasms/diagnostic imaging , Peritoneal Neoplasms/secondary , Radiography, Thoracic , Retrospective Studies , Stomach Neoplasms/pathology , Tomography, X-Ray Computed
5.
Zhonghua Er Ke Za Zhi ; 57(1): 27-32, 2019 Jan 02.
Article in Chinese | MEDLINE | ID: mdl-30630228

ABSTRACT

Objective: To investigate the predominant genotypes and epidemiological characteristics of human adenovirus (HAdV) in pediatric community-acquired pneumonia (CAP) in China. Methods: This was a repeated cross sectional study. Between November 2014 and November 2016, nasopharyngeal aspirates (NPAs) or throat swabs from each hospitalized pediatric patients diagnosed as CAP in 12 hospitals in Northern and Southern China were collected. Respiratory specimens were screened for 18 respiratory viruses including HAdV by using Luminex xTAG RVP Fast V2 multiplex Assay. Typing of HAdV and analysis for the epidemiological characteristic of HAdV were performed. Results: (1) A total of 2 723 hospitalized pediatric patients with CAP were enrolled in this study and 156 (5.7%, 156/2 723) respiratory specimens were positive for HAdV, and 74 (6.6%, 74/1 128) and 82 (5.1%, 82/1 595) were in Northern and Southern China, respectively. There was no significant difference in the positive detection rate between the Northern and Southern China. (2) In Northern China, the HAdV positive rate of children at the age of <6 months, 6 months-<1 years, 1-<3 years, 3-<5 years and ≥5 years was 5.9%(6/101), 6.7%(7/104), 10.3%(34/331), 4.1%(11/266) and 4.9%(16/326), respectively, and the incidence of HAdV infection peaked in children aged 1-3 years (χ(2)=11.511, P=0.021). While in Southern China the HAdV positive rate of children at the age of <6 months, 6 months-<1 years, 1-<3 years, 3-<5 years and ≥5 years was 2.2% (7/312), 4.6% (12/259), 6.3% (31/494), 7.3% (18/245) and 4.9%(14/285), respectively. There was no significant difference in the positive detection rate among age groups. (3) In 2015, the highest detection rate of HAdV in northern China was 12.5% (25/200) in winter, and in Southern China was 6.7% (35/525) in spring and 5.3% (19/357) in summer. (4) In 108 cases of HAdV positive specimens typing was done and 80 in cases classification was successfully performed.Totally 7 genotypes of HAdV, including HAdV-3 (n=32), HAdV-7 (n=9), HAdV-1 (n=12), HAdV-2 (n=15), HAdV-5 (n=10), HAdV-6 (n=1) and HAdV-4 (n=1), were detected. The predominant HAdV genotypes were HAdV-3 (30.8%, 8/26) and HAdV-7 (26.9%, 7/26) in Northern China, while HAdV-3 (44.4%, 24/54) and HAdV-2 (22.2%, 12/54) were the most prevalent genotypes in Southern China. Conclusions: HAdV is an important viral pathogen in pediatric CAP. The predominant HAdV genotypes and peak seasons of HAdV infections were different between Northern and Southern China. The predominant HAdV genotypes were HAdV-3 and HAdV-7 in Northern China, while HAdV-3 and HAdV-2 in Southern China. The peak season of HAdV infections was winter in Northern China. However, HAdV infections are more common in spring and summer in Southern China.


Subject(s)
Adenovirus Infections, Human , Adenoviruses, Human , Respiratory Tract Infections , Adenovirus Infections, Human/epidemiology , Adenovirus Infections, Human/genetics , Adenoviruses, Human/genetics , Child , Child, Preschool , China , Community-Acquired Infections/epidemiology , Community-Acquired Infections/genetics , Cross-Sectional Studies , Genotype , Humans , Infant , Infant, Newborn , Pneumonia , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/genetics
6.
Genet Mol Res ; 15(1)2016 Feb 05.
Article in English | MEDLINE | ID: mdl-26909955

ABSTRACT

This study investigated the effects induced by co-culturing human primary basic fibroblasts (HPBFs) with 16-human bronchial epithelial cells (16-HBE) infected with respiratory syncytial virus (RSV), in particular the transformation of HPBFs into myofibroblasts and secretion of extracellular matrix proteins. HPBFs were co-cultured with 16-HBE cells infected with RSV and quantitatively analyzed. We constructed models of HPBFs co-cultured with 16-HBE cells that were either uninfected (control group) or infected with RSV (experimental group). Following initiation of co-cultures, HPBFs and supernatants were collected at 24-h intervals up to 120 h. Expression of α-smooth muscle actin (α-SMA) was detected by indirect immunofluorescence and western blotting, while type I collagen (Col I) and fibronectin were analyzed by competitive enzyme-linked immunosorbent assays. After 72 h, α-SMA expression increased in HPBFs cultured with RSV-infected 16-HBE relative to uninfected controls, reaching its highest level at 96 h. Similarly, Col I secretion was also higher in HPBFs co-cultured with RSV-infected 16-HBE relative to uninfected controls; Col I secretion increased with time and reached its highest level at 120 h. HPBFs were transformed into myofibroblasts following co-culture with RSV-infected 16-HBE, which when combined with the observed increase in Col I secretion suggests that airway remodeling would then be promoted.


Subject(s)
Airway Remodeling , Epithelial Cells/virology , Fibroblasts/pathology , Myofibroblasts/pathology , Respiratory Syncytial Virus Infections/pathology , Respiratory Tract Infections/pathology , Actins/metabolism , Bronchi/pathology , Bronchi/virology , Coculture Techniques , Collagen Type I/metabolism , Epithelial Cells/pathology , Fibroblasts/metabolism , Fibronectins/metabolism , Humans , Myofibroblasts/metabolism , Respiratory Syncytial Virus Infections/metabolism , Respiratory Syncytial Virus Infections/virology , Respiratory Syncytial Viruses , Respiratory Tract Infections/metabolism , Respiratory Tract Infections/virology
7.
Data Brief ; 5: 71-6, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26484358

ABSTRACT

Five subjects with mucopolysaccharidosis type I and symptomatic cervical spinal stenosis received intrathecal laronidase in a 4-month pilot study and/or a 12-month extension study [1]. Clinical descriptions of study subjects, nonserious adverse events, individual data tables, and scoring system methods are provided. There were ten nonserious adverse events that occurred in more than one study subject. Somatosensory evoked potentials were absent in two subjects and normal in two subjects, limiting their utility as an endpoint. There were no significant changes in magnetic resonance imaging of cervical spinal cord or brain, pulmonary function tests, or cerebrospinal fluid opening pressure. These data are presented along with the scoring methods used in evaluation of the study subjects.

9.
Genet Mol Res ; 13(4): 8385-95, 2014 Oct 20.
Article in English | MEDLINE | ID: mdl-25366732

ABSTRACT

We explored the interaction of 6 candidate genetic mutations in essential hypertension (EH). The mutations AGT M235T, ACE I/D, eNOS Glu298Asp, ET-2 A985G, ANP T2238C, and NPRC A-55C were detected using a genechip microarray in 100 patients with EH and 97 controls from the Han population living in the Yunnan Province of China. Risks of EH were evaluated with respect to a combination of these genotypes. Interactions were analyzed using multifactor dimensionality reduction (MDR). P values were corrected using Bonferroni's adjustment. Results showed that CC genotype frequencies for NPRC A-55C (0.540) in EH were significantly higher than those in controls (0.237, Pc < 0.01; odds ratio (OR) = 3.777; 95% confidence interval (CI) = 2.050-6.960). The OR for NPRC A-55C CC combined with ET-2 A985G GG increased to 4.673 and to 5.529 when the MT genotype of AGT M235T, the EE genotype of eNOS Glu298Asp, the GG genotype of ET-2 A985G, and the CC genotype of NPRC A-55C were combined. MDR showed that ET-2/NPRC is the best model (OR = 4.002; 95%CI = 2.1597-7.4159). The CC genotype for NPRC A-55C and the G allele for ET-2 A985G were associated with susceptibility to EH. Although the contributions of the candidate genes differ, they may have cooperative effects on conferring risk for EH. Moreover, potential gene-gene interactions were found between ET-2 A985G and NPRC A-55C in EH.


Subject(s)
Epistasis, Genetic , Hypertension/genetics , Aged , Alleles , Case-Control Studies , Essential Hypertension , Female , Gene Frequency , Genetic Association Studies , Genetic Loci , Genotype , Humans , Hypertension/physiopathology , Male , Middle Aged , Odds Ratio , Polymorphism, Genetic
10.
Vet Parasitol ; 174(3-4): 213-7, 2010 Dec 15.
Article in English | MEDLINE | ID: mdl-20850926

ABSTRACT

The prevalence of coccidial infection in sheep and goats was examined in Heilongjiang Province, northeastern China between January 2007 and June 2009. A total of 508 faecal samples (309 from sheep and 199 from goats) were collected from eight sheep and goat rearing administrative regions. Oocysts in faecal samples were detected using a flotation technique, sporulated and identified to species based on morphological features of the sporulated oocysts. The overall prevalence of coccidial infection was 90.9% (462/508), with prevalence of 92.9% (287/309) for sheep and 87.9% (175/199) for goats. 13 species of Eimeria were identified, namely, E. bakuensis, E. faurei, E. parva, E. ahsata, E. crandallis, E. granulosa, E. intricata, E. pallida, E. christenseni, E. caprina, E. alijevi, E. apsheronica and E. arloingi. In sheep, the most common Eimeria species were E. ahsata (67.2%), E. parva (59.9%) and E. bakuensis (44.3%). In goats, the more prevalent species were E. christenseni (78.3%), E. alijevi (73.7%), E. caprina (62.3%) and E. arloingi (44.6%). Concurrent infection with two to eight species was common. However, no clinical symptoms were observed in the examined sheep and goats. The results of the present investigation have implications for the control of coccidial infections in sheep and goats in northeastern China.


Subject(s)
Coccidiosis/epidemiology , Goat Diseases/epidemiology , Sheep Diseases/epidemiology , Animals , China/epidemiology , Goats , Sheep
11.
Singapore Med J ; 51(3): 247-52, 2010 Mar.
Article in English | MEDLINE | ID: mdl-20428748

ABSTRACT

INTRODUCTION: The aim of this study was to identify factors associated with poor academic achievement during the early school years. METHODS: This was a cross-sectional study of urban Primary Two children. Sociodemographic and medical data were obtained from questionnaires and interviews. Achievement was based on marks obtained in the core subjects of the Primary One examination. All students underwent the Raven's Standard Progressive Matrices test as a general measure of cognitive ability, audiometry and visual tests, and standardised measurements of weight and height. RESULTS: Out of 1,470 eligible children, 206 (14 percent) had poor academic achievement. Of the 919 children who participated in the study, 111 (12.1 percent) had poor achievement compared with 95 (17.2 percent) of the 551 non-participants. Using logistic regression analysis, the factors that were found to be independently associated with poor academic achievement were lower mean Raven scores (p-value is less than 0.001), lower mean socioeconomic status scores (p-value is less than 0.001), larger sibship size (p-value is 0.031), male gender (odds ratio [OR] 1.7; 95 percent confidence interval [CI] 1.1-2.65) and a history of prematurity (OR 14; 95 percent CI 2-97.8). CONCLUSION: Cognitive ability, gender, prematurity and social factors contribute to poor academic achievement during the early school years. The higher proportion of poor achievers among non-participants warrants further attention.


Subject(s)
Educational Measurement , Schools , Students , Audiometry , Child , Child Welfare , Cognition , Confidence Intervals , Cross-Sectional Studies , Educational Status , Female , Humans , Intelligence Tests , Logistic Models , Malaysia , Male , Odds Ratio , Regression Analysis , Risk Factors , Sex Factors , Socioeconomic Factors , Surveys and Questionnaires , Urban Population , Vision Tests
12.
Acta Trop ; 109(3): 171-5, 2009 Mar.
Article in English | MEDLINE | ID: mdl-19081387

ABSTRACT

Parasites of the genus Orientobilharzia belong to Platyhelminthes, Trematoda, Digenea, Schistosomatidae, and the type species is Orientobilharzia turkestanicum. O. turkestanicum was first described by Skrjabin from cattle in Russian Turkestan in 1913. Adult worms of Orientobilharzia species live in the portal veins or intestinal veins of cattle, sheep and other mammals, and often cause orientobilharziasis in China, India, Mongolia, Pakistan, Iraq, Iran in Asia, and Russia and Turkey in Europe. More importantly, the cercariae of Orientobilharzia species can infect humans and often cause cercarial dermatitis. Though Orientobilharzia species have been confirmed as zoonotic agents, they have been largely neglected, compared with other pathogens causing cercarial dermatitis, such as Trichobilharzia spp., Schistosoma spindale and Bilharziella sp., which have attracted considerable attention. Here we review the current status of knowledge on the taxonomy of Orientobilharzia spp., human and animal infections with Orientobilharzia spp., and address some considerations for further work on the systematics and pathogenesis of these organisms.


Subject(s)
Schistosomatidae/classification , Schistosomatidae/physiology , Trematode Infections/epidemiology , Trematode Infections/veterinary , Zoonoses/epidemiology , Zoonoses/parasitology , Animals , Asia/epidemiology , Europe/epidemiology , Humans , Schistosomatidae/isolation & purification
13.
Tech Coloproctol ; 12(1): 1-6; discussion 6, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18512006

ABSTRACT

Surgery, chemotherapy and radiotherapy have been the mainstay of colorectal cancer treatment. There is however current intense research on traditional Chinese medicine (TCM) as novel or additional treatment methods for colorectal cancer. This article reviews the current use of TCM in colorectal cancer so as to increase the awareness of colorectal surgeons. The pathogenesis of colorectal cancer according to TCM is discussed. TCM has been used successfully during the perioperative period to relieve intestinal obstruction, reduce postoperative ileus and reduce urinary retention after rectal surgery. Good results have been reported in the treatment of the complications of chemotherapy and radiation enterocolitis. Favourable results have also been shown in the use of TCM either alone or in combination with chemotherapy to treat advanced colorectal cancer. Molecular studies have shown some TCM compounds to reduce tumour cell proliferation and induce apoptosis. Although the reported results of TCM have been exciting thus far, problems of lack of consensus on treatment regimes and questions on the reliability, validity and applicability of published studies prevent its widespread use. There is now an urgent need for colorectal surgeons to work with TCM physicians in the continuing research on this 6,000-year-old art so as to realize its full potential for our patients.


Subject(s)
Colorectal Neoplasms/therapy , Medicine, Chinese Traditional/methods , Combined Modality Therapy , Humans
15.
Arch Otolaryngol Head Neck Surg ; 127(8): 921-5, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11493199

ABSTRACT

BACKGROUND: Earlier studies have mapped the autosomal recessive nonsyndromic deafness locus, DFNB15, to chromosomes 3q21.3-q25.2 and 19p13.3-13.1, identifying one of these chromosomal regions (or possibly both) as the site of a deafness-causing gene. Mutations in unconventional myosins cause deafness in mice and humans. One unconventional myosin, myosin 1F (MYO1F), is expressed in the cochlea and maps to chromosome 19p13.3-13.2. OBJECTIVE: To evaluate MYO1F as a candidate gene for deafness at the DFNB15 locus by determining its genomic structure and screening each exon for deafness-causing mutations to identify possible allele variants of MYO1F segregating in the DFNB15 family. METHODS: We used radiation hybrid mapping to localize MYO1F on chromosome arm 19p. We next determined its genomic structure using multiple long-range polymerase chain reaction experiments. Using these data, we completed mutation screening using single-stranded conformational polymorphism analysis and direct sequencing of affected and nonaffected persons in the original DFNB15 family. RESULTS: Radiation hybrid mapping placed MYO1F in the DFNB15 interval, establishing it as a positional candidate gene. Its genomic structure consists of 24 coding exons. No mutations or genomic rearrangements were found in the original DFNB15 family, making it unlikely that MYO1F is the disease-causing gene in this kindred. CONCLUSIONS: Although we did not find MYO1F allele variants in one family with autosomal recessive nonsyndromic hearing loss, the gene remains an excellent candidate for hereditary hearing impairment. Given its wide tissue expression, MYO1F might cause syndromic deafness.


Subject(s)
Chromosomes, Human, Pair 19 , Deafness/genetics , Myosins/genetics , Alleles , Animals , Chromosome Mapping , DNA, Complementary/genetics , Exons/genetics , Humans , Mice , Mutation , Pedigree , Polymerase Chain Reaction , Polymorphism, Single-Stranded Conformational , Radiation Hybrid Mapping , Sequence Analysis, DNA
16.
Women Health ; 32(4): 1-15, 2001.
Article in English | MEDLINE | ID: mdl-11548133

ABSTRACT

Walking for exercise is becoming widely recognized for bestowing health benefits. This study examined the association of walking for exercise and mood in sedentary, ethnic minority women over a five-month period. Ethnic minority women (N = 102) participated in a randomized, controlled trial of a 7-week behaviorally based telephone and mail intervention that promoted the adoption of walking for exercise compared to a non-behavioral minimal intervention. At 2-month post-test and 5-month follow-up, participants reported significant decreases in depressive mood and increases in vigor. Increase in walking over the course of the study was associated with change in vigor. Limited evidence was found to support a relationship between walking for exercise and mood improvement in ethnic-minority women.


Subject(s)
Affect/physiology , Ethnicity/psychology , Exercise/psychology , Health Behavior/ethnology , Health Promotion/methods , Walking/psychology , Women's Health , Adult , Analysis of Variance , Counseling , Female , Humans , Middle Aged , Persuasive Communication , Prospective Studies , Telephone , United States
17.
Surgery ; 130(2): 378-81, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11490374

ABSTRACT

BACKGROUND: Pulsatile pressure induced by the beating heart causes cyclic strain on arterial endothelial cells and smooth muscle cells (SMCs). This study examined whether Akt, a serine/threonine protein kinase known to promote cell survival by inhibiting apoptosis, is activated by cyclic strain in bovine aortic SMCs. METHODS: Bovine aortic SMCs were cultured on flexible-bottomed membranes and then serum-starved for 24 to 36 hours. The cells were then exposed to 150-mm Hg repetitive deformations, which created an average of 10% strain on the monolayer SMCs at a frequency of 60 cycles/minute for 0 (negative control) and 30 minutes. Platelet-derived growth factor (PDGF)--stimulated SMCs were used as positive controls. Phosphorylation of Akt was determined by means of Western blot analysis. An apoptosis assay (TUNEL) was also performed on SMCs exposed to cyclic strain. RESULTS: Akt phosphorylation was significantly increased over that of the negative control after 30 minutes of cyclic strain and in the PDGF group. Cyclic strain did not increase the prevalence of apoptosis in SMCs over the control. CONCLUSIONS: Cyclic strain activated the pro-survival Akt kinase. The pro-survival function was supported by the fact that cyclic strain did not increase apoptosis in bovine aortic SMCs. This experiment suggests that cyclic strain may induce arterial wall thickening by tipping the balance toward arterial SMC proliferation through the inhibition of apoptosis.


Subject(s)
Apoptosis/physiology , Muscle, Smooth, Vascular/cytology , Muscle, Smooth, Vascular/enzymology , Protein Serine-Threonine Kinases , Proto-Oncogene Proteins/metabolism , Animals , Aorta, Thoracic/cytology , Cattle , Cells, Cultured , In Situ Nick-End Labeling , Phosphorylation , Proto-Oncogene Proteins c-akt
18.
Endothelium ; 8(1): 1-10, 2001.
Article in English | MEDLINE | ID: mdl-11409847

ABSTRACT

The irregular distribution of plaque in the vasculature results from the interaction of local hemodynamic forces with the vessel wall. One well-characterized force is cyclic circumferential strain, the repetitive pulsatile pressure distention on the arterial wall. This review summarizes current research, which has aimed to elicit the signal transduction pathway by which cyclic strain elicits functional and structural responses in endothelial cells; specifically, it summarizes the signaling pathway that begins with the reorganization of integrins. One method by which these extracellular matrix receptors affect signal transduction is through their ability to initiate the process of phosphorylation on tyrosine residues of cytoplasmic protein kinases, including focal adhesion kinase. The strain-induced pathway appears to also involve ras and the mitogen-activated protein kinase family of enzymes, and preliminary data suggests a role for src as well. Ultimately, it is the regulation of gene expression through the modulation of transcription factors that allows endothelial cells to respond to changes in local hemodynamics.


Subject(s)
Endothelium, Vascular/physiology , Integrins/physiology , Signal Transduction/physiology , Blood Pressure/physiology , Cell Membrane/physiology , Extracellular Matrix Proteins/physiology , Focal Adhesion Kinase 1 , Focal Adhesion Protein-Tyrosine Kinases , Hemodynamics/physiology , Humans , Protein-Tyrosine Kinases/metabolism , Pulse , Stress, Mechanical , Umbilical Veins/physiology , Vasodilation
19.
Eur J Vasc Endovasc Surg ; 21(5): 383-92, 2001 May.
Article in English | MEDLINE | ID: mdl-11352511

ABSTRACT

There are many reports of how IPC is used effectively in the clinical setting; including the prevention of deep venous thrombosis, improvement of circulation in patients with lower extremity arterial diseases, reduction of lymphoedema, and the healing of venous ulcers. However, despite the widely accepted use of IPC, it is still unclear how IPC actually exerts its beneficial effects. The exact physiological mechanisms of action are unknown. The clinical utility of IPC and the putative mechanisms by which IPC could exert its therapeutic effect will be reviewed. The paper will examine the mechanical effects of IPC exerted on the lower extremity, and the subsequent biochemical changes in the circulation. In vitro studies of the effects of mechanical stress such as compressive strain and shear on cultured endothelial cells, and their clinical relevance to IPC will also be reviewed.


Subject(s)
Gravity Suits , Adult , Biomechanical Phenomena , Blood Circulation/physiology , Blood Vessels/physiology , Humans , Venous Thrombosis/prevention & control
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