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1.
Cureus ; 16(5): e60420, 2024 May.
Article in English | MEDLINE | ID: mdl-38883098

ABSTRACT

INTRODUCTION: Child abuse refers to any type of mistreatment of a child, perpetrated by a parent, caregiver, or another individual in a custodial capacity, which may lead to instances of physical, sexual, or emotional abuse. Physicians play a crucial role in identifying and managing this phenomenon in the healthcare setting, as the number of unreported cases increases globally. METHODS: A questionnaire-based cross-sectional study was conducted between 2022 and 2023 among physicians practicing in Saudi Arabia to assess their knowledge, awareness, and attitude toward child abuse. The data were analyzed using IBM SPSS Statistics for Windows, Version 26 (Released 2019; IBM Corp., Armonk, New York, United States). RESULTS: A total of 153 physicians were involved in this study, in which 65 participants (42.5%) indicated poor awareness of child abuse, while 79 participants (51.6%) indicated moderate knowledge of child abuse. Additionally, lack of knowledge was the most common barrier to reporting child abuse in 87 participants (56.9%). A positive significant correlation was identified between awareness and knowledge and between knowledge and attitude. Also, it was found that a higher attitude score was more associated with being male, having less experience, practicing in the emergency medicine department, and working in a governmental hospital. CONCLUSION: These results highlight the significance of implementing specialized training programs and workshops focused on identifying and reporting child abuse, as well as providing guidelines for recognizing signs of abuse and taking appropriate intervention measures.

2.
Ann Med Surg (Lond) ; 85(12): 5919-5925, 2023 Dec.
Article in English | MEDLINE | ID: mdl-38098559

ABSTRACT

Introduction: Systemic lupus erythematosus (SLE) is a systemic disease, with unknown etiology. The authors aimed in this study to determine the connection between mean platelet volume (MPV) and disease activity of SLE. Although it has been studied in other rheumatological conditions like rheumatoid arthritis, its role in adult patients with SLE needs to be defined, especially in Syria. Materials and methods: The authors have included in a cross-sectional study, 80 patients with SLE and 80 controls.The SLE group was divided into two groups based on their disease activity index: the active disease group and the non-active disease group.In all groups, MPV and erythrocyte sedimentation rate (ESR) were analyzed. Clinical findings and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) were evaluated in all patients. Results: MPV was significantly lower in SLE patients compared to the control group (8.49±1.2 fl and 10.0±0.5 fl, respectively) (P=0.001). A decrease in MPV below the cut-off value (7.2 fl) increased the risk of active disease by an odds ratio of 9.79 (95% CI: 3.4-27.9) (P<0.001). Conclusion: MPV may be a disease activity indicator in patients with SLE. MPV is reduced in patients with active SLE and presents an inverse correlation with SLEDAI.

3.
Cureus ; 15(8): e42780, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37664260

ABSTRACT

Background and objective While the Kingdom of Saudi Arabia (KSA) has had a hepatitis C virus (HCV) elimination program in place since 2015, there have been limited studies investigating the effectiveness and safety of direct-acting antivirals (DAAS) based on the Ministry of Health (MOH) surveillance data. In light of this, this study was conducted to assess the effectiveness and safety of DAAS (glecaprevir/pibrentasvir, daclatasvir/sofosbuvir, or other combinations) in treating HCV cases in Saudi Arabia as per the MOH data from 2017 to 2021. Methods This was a retrospective cohort study involving recorded HCV cases in the national hepatitis surveillance database of MOH across all regions of KSA from 2017 to 2021. Statistical analyses were performed using IBM SPSS Statistics software (IBM Corp., Armonk, NY). Continuous variables were expressed as mean ± standard deviation (SD), and categorical variables were presented as numbers (percentages). An independent t-test was used for continuous variables, and a Chi-square analysis was used for categorical variables. A confidence interval of 95%, a margin of error of 0.05, a precision of 2%, and a 5% level of significance were employed. Results Regarding demographic characteristics, age was significantly associated with HCV infection (p=0.002). Similarly, nationality had a highly significant association with HCV infection (p=0.004). Regarding clinical characteristics, creatinine levels were significantly associated with HCV infection (p=0.009). As for effectiveness, all participants had a positive polymerase chain reaction (PCR) for HCV at enrolment (n=4806) and were DAAS-naïve. After the completion of the first DAAS course, 99.5% (4781) had negative PCRs 12 weeks post-treatment completion; however, the PCR remained positive for some patients (0.5%, n=25), which became negative after receiving the second DAAS course, resulting in complete cure of HCV infection and a 100% negative PCR among all participants. With regard to safety, no side effects were recorded in the cohort and hence the safety aspect was not analyzed. Conclusion Univariate analysis revealed that nationality (non-Saudi), age, and creatinine levels were significantly associated with HCV infection. However, only nationality showed a significant association with HCV infection following multivariate logistic regression adjustment. We believe that these insights will help guide the creation of clinical guidelines and promote evidence-based decision-making in the management of HCV in Saudi Arabia.

4.
Diagnostics (Basel) ; 13(4)2023 Feb 15.
Article in English | MEDLINE | ID: mdl-36832230

ABSTRACT

This case-control study aimed to assess the size and echogenicity of inflamed tonsils using ultrasonography. It was carried out at different hospitals, nurseries, and primary schools in Khartoum state. About 131 Sudanese volunteers between 1 and 24 years old were recruited. The sample included 79 volunteers with normal tonsils and 52 with tonsillitis according to hematological investigations. The sample was divided into groups according to age-1-5 years old, 6-10 years old, and more than ten years. Measurements in centimeters of height (AP) and width (transverse) of both tonsils (right and left) were taken. Echogenicity was assessed according to normal and abnormal appearances. A data collection sheet containing all the study variables was used. The independent samples test (t-test) showed an insignificant height difference between normal controls and cases with tonsillitis. The transverse diameter increased significantly with inflammation (p-value < 0.05) for both tonsils in all groups. Echogenicity can differentiate between normal and abnormal tonsils (p-value < 0.05 using the chi-square test) for samples from 1-5 years and 6-10 years. The study concluded that measurements and appearance are reliable indicators of tonsillitis, which can be confirmed with the use of ultrasonography, helping physicians to make the correct diagnosis and decisions.

5.
PLoS One ; 15(8): e0237154, 2020.
Article in English | MEDLINE | ID: mdl-32797055

ABSTRACT

Data prioritization of heterogeneous data in wireless sensor networks gives meaning to mission-critical data that are time-sensitive as this may be a matter of life and death. However, the standard IEEE 802.15.4 does not consider the prioritization of data. Prioritization schemes proffered in the literature have not adequately addressed this issue as proposed schemes either uses a single or complex backoff algorithm to estimate backoff time-slots for prioritized data. Subsequently, the carrier sense multiple access with collision avoidance scheme exhibits an exponentially increasing range of backoff times. These approaches are not only inefficient but result in high latency and increased power consumption. In this article, the concept of class of service (CS) was adopted to prioritize heterogeneous data (real-time and non-real-time), resulting in an optimized prioritized backoff MAC scheme called Class of Service Traffic Priority-based Medium Access Control (CSTP-MAC). This scheme classifies data into high priority data (HPD) and low priority data (LPD) by computing backoff times with expressions peculiar to the data priority class. The improved scheme grants nodes the opportunity to access the shared medium in a timely and power-efficient manner. Benchmarked against contemporary schemes, CSTP-MAC attained a 99% packet delivery ratio with improved power saving capability, which translates to a longer operational lifetime.


Subject(s)
Computer Communication Networks , Electronic Data Processing/methods , Wireless Technology , Algorithms , Models, Theoretical , Radio , Software Design
6.
Case Rep Dent ; 2019: 2637825, 2019.
Article in English | MEDLINE | ID: mdl-31612083

ABSTRACT

Solitary median maxillary central incisor (SMMCI) is a rare dental anomaly. It is estimated to occur in 1 : 50,000 live births. The SMMCI tooth differs from the normal central incisor in that the crown form is symmetric and it develops and erupts precisely in the midline of the maxillary dental arch in both primary and permanent dentitions. The presence of SMMCI with hemifacial microsomia (HFM) is a very rare clinical condition. We report a case of SMMCI in a female of African ethnic origin, who presented with SMMCI in permanent dentition with mild nasal stenosis. An early diagnosis of SMMCI is important, since it may be a sign for other severe congenital or developmental abnormalities. Therefore, systematic follow-up and close monitoring of the growth and development of SMMCI patients are crucial.

7.
J Pediatr Adolesc Gynecol ; 31(5): 451-458, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29524595

ABSTRACT

STUDY OBJECTIVE: On this study we sought to determine the relationship of bleeding disorders to iron deficiency anemia. Additionally, this study was undertaken to examine all current treatment modalities used in a menorrhagia clinic with respect to heavy menstrual bleeding management to identify the most effective options for menstrual management in the setting of an underlying bleeding disorder. DESIGN, SETTING, PARTICIPANTS, INTERVENTIONS, AND MAIN OUTCOME MEASURES: We performed a retrospective chart review of adolescents younger than 21 years with heavy menstrual bleeding attending a multidisciplinary hematology-adolescent gynecology clinic. Information including demographic characteristics, bleeding diathesis, hematologic parameters, treatment, and the diagnosis was extracted from each chart. Subjects were grouped into 2 categories on the basis of the diagnosis of a bleeding disorder. Hemoglobin level, iron deficiency anemia, and need for transfusion were compared between a bleeding disorder and no bleeding disorder group. Subjects were grouped into categories depending on hormonal modality and treatment success of the groups were compared. RESULTS: Seventy-three subjects were tested for a bleeding disorder. Of the subjects who completed testing, 34 (46%) were diagnosed with a bleeding disorder. Thirty-nine subjects (54%) had heavy menstrual bleeding because of other causes. There was no significant difference in hemoglobin between those with and without a bleeding disorder. Iron deficiency anemia was significantly higher in subjects without a bleeding disorder. In a comparison of hormone therapy success, the levonorgestrel intrauterine device (89%, 8 out of 9 subjects) had the highest rate of menstrual suppression followed by norethindrone acetate 5-10 mg/d (83%, 5 out of 6 subjects), and the transdermal patch (80%, 4 out of 5 subjects). All subjects using tranexamic acid as well as hormonal therapy had 100% achievement of menstrual suppression. CONCLUSION: A high frequency of bleeding disorders was found in those tested. Subjects with a bleeding disorder were less likely to present with severe anemia requiring blood transfusion and less likely to have iron deficiency anemia. Although combined oral contraceptives were commonly used clinically for menstrual suppression, they were not found to be the most effective option.


Subject(s)
Anemia, Iron-Deficiency/etiology , Blood Coagulation Disorders/complications , Menorrhagia/therapy , Adolescent , Anemia, Iron-Deficiency/epidemiology , Antifibrinolytic Agents/administration & dosage , Blood Coagulation Disorders/epidemiology , Blood Coagulation Disorders/therapy , Blood Transfusion/statistics & numerical data , Child , Contraceptive Agents, Female/administration & dosage , Contraceptive Agents, Female/adverse effects , Female , Hemoglobins/analysis , Humans , Menorrhagia/etiology , Menstruation , Retrospective Studies , Risk Factors
9.
Arch Trauma Res ; 5(1): e24596, 2016 Mar.
Article in English | MEDLINE | ID: mdl-27148496

ABSTRACT

BACKGROUND: Traumatic dental injuries to anterior teeth are a significant public health problem, not only because their prevalence is relatively high, but also because they have considerable impact on children's daily lives. Traumatic dental injuries (TDIs) cause physical and psychological discomfort, pain and other negative impacts, such as tendency to avoid laughing or smiling, which can affect social relationships. OBJECTIVES: This study aimed to assess the prevalence of traumatic dental injuries to anterior teeth among 12-year-old school children in Kashmir, India. PATIENTS AND METHODS: A cross-sectional study was conducted in private and government schools of India among 1600 schoolchildren aged 12 years. In addition to recording of the type of trauma (using Ellis and Davey classification of fractures, 1970), over jet, Angle's molar relation and lip competence were also recorded. The socioeconomic status and academic performance of the study subjects were registered. The data obtained were compiled systematically and then statistically analyzed. The statistical significance for the association between the traumatic injury and the variables was analyzed using the chi-square test. Logistic regression was used to identify potential risk predictors of TDIs. RESULTS: The overall prevalence of TDI to anterior teeth was found to be 9.3%. The TDI to anterior teeth in male was more than female, but the difference was statistically nonsignificant (P < 0.01). Falls and sports were the most common causes of trauma in the present study. The highest potential risk factor for the occurrence of trauma was over jet. Academic performance was found to be significantly associated to TDI to anterior teeth, when analyzed in a multiple regression model. CONCLUSIONS: It was concluded that the prevalence of traumatic dental injuries was 9.3%. Traumatic dental injuries among children exhibit complex interaction between the victims' oral conditions and their behavior. Therefore, prevention should consider a number of characteristics such as oral predisposing factors, environmental determinants and human behavior. It is recommended that specific and proper public places for leisure and sports activities, with impact-absorbing surfaces around the items on which children are most likely to fall, should be provided.

10.
Mymensingh Med J ; 24(2): 424-6, 2015 Apr.
Article in English | MEDLINE | ID: mdl-26007279

ABSTRACT

Surgical site infections (SSIs) are the second most common health care associated infection reported to the National Health Safety Network of the centre of disease control and prevention. SSIs by Mycobacterium tuberculosis are uncommon and diagnosis can be missed. Our patient had primary tuberculosis at surgical site without any evidence of tuberculosis at initial investigation. She presented with repeated discharging sinus at the wound of elective lower uterine caesarean section (LUCS). The case was diagnosed by histo-pathological evidence of chronic granulomatous lesion suggestive of tuberculosis from the excised tissue from wound and detection of acid fast bacilli (AFB) from swab by Ziehl Neelsen staining. After proper diagnosis the patient was treated with anti-tubercular drugs regiment for six months as per schedule of national guidelines for management of tuberculosis of Bangladesh Government. Then the patient was cured from unusual long sufferings.


Subject(s)
Surgical Wound Infection , Bangladesh , Female , Humans , Mycobacterium tuberculosis , Postoperative Period , Pregnancy , Tuberculosis
12.
J Clin Diagn Res ; 8(12): ZC28-30, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25654026

ABSTRACT

BACKGROUND: Forensic odontology nowadays has become a developing science and is of great importance to society. It is important that dental practitioners should have a proper knowledge of forensics as the need has increased greatly over the last decades due to the unprecedented demand from the criminal justice including terrorism in Kashmir valley (J&K India). MATERIALS AND METHODS: Data was collected based on questionnaire survey among qualified dental practitioners related to their awareness of forensic odontology. RESULTS: A total number of 235 dental practitioners responded to the questionnaire. RESULTS showed that there was a low confidence, in handling of forensic odontology related cases among dental practitioners and majority of dental practitioners were not having any formal training in forensic odontology. CONCLUSION: Each dental practitioner has a responsibility to understand the forensic implications associated with the practice of his profession and thus he should work sincerely enough so to ensure his contribution in the field of forensic odontology.

13.
J Int Acad Periodontol ; 16(4): 115-20, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25654965

ABSTRACT

OBJECTIVE: Stress has an adverse effect on oral health and is a risk factor for plaque-associated diseases. The present study aims to assess the effect of academic stress on plaque and gingival health among dental students of Moradabad, India. METHODS: Fifty eligible dental students (age 18 - 22 years) undergoing university examinations participated in the study. Students were examined for plaque index (PII) and gingival index (GI) scores during and after their examinations. Stress levels (using the DASS 21 questionnaire) and oral hygiene behavior were also assessed during and after university examinations and the data were subjected to statistical analysis. RESULTS: The average PII and GI were 1.213 and 0.944, respectively, during examinations and 0.845 and 0.467, respectively, after examinations. The average stress scores were 15.66 and 9.94 during and after examinations, respectively. Eighty-eight percent of the students brushed once and 12% of the students brushed twice during the university examinations, whereas 76% brushed once and 24% of the students brushed twice after their examinations. Thirty-four percent of the subjects rated their thoroughness of brushing as good during university examinations whereas the percentage increased to 80% after the examinations. All the differences were found to be statistically significant. CONCLUSION: Students appearing for the university examinations showed increased stress levels. Moreover, under conditions of stress, the students generally neglected their oral health care and adverse effects on their plaque and gingival scores were observed. Thus, it might be concluded that academic stress has an adverse effect on plaque levels and gingival status in students.


Subject(s)
Dental Plaque/classification , Gingivitis/classification , Stress, Physiological/physiology , Stress, Psychological/physiopathology , Students, Dental/psychology , Adolescent , Dental Plaque Index , Educational Measurement , Female , Health Behavior , Humans , India , Male , Oral Hygiene/classification , Periodontal Index , Toothbrushing/statistics & numerical data , Young Adult
14.
Indian J Anaesth ; 57(3): 327, 2013 May.
Article in English | MEDLINE | ID: mdl-23983310
15.
Indian J Anaesth ; 57(2): 212-3, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23825834
16.
Curr Biol ; 23(5): 372-81, 2013 Mar 04.
Article in English | MEDLINE | ID: mdl-23434278

ABSTRACT

BACKGROUND: Disruption of circadian (daily) timekeeping enhances the risk of metabolic syndrome, obesity, and type 2 diabetes. While clinical observations have suggested that insulin action is not constant throughout the 24 hr cycle, its magnitude and periodicity have not been assessed. Moreover, when circadian rhythmicity is absent or severely disrupted, it is not known whether insulin action will lock to the peak, nadir, or mean of the normal periodicity of insulin action. RESULTS: We used hyperinsulinemic-euglycemic clamps to show a bona fide circadian rhythm of insulin action; mice are most resistant to insulin during their daily phase of relative inactivity. Moreover, clock-disrupted Bmal1-knockout mice are locked into the trough of insulin action and lack rhythmicity in insulin action and activity patterns. When rhythmicity is rescued in the Bmal1-knockout mice by expression of the paralogous gene Bmal2, insulin action and activity patterns are restored. When challenged with a high-fat diet, arhythmic mice (either Bmal1-knockout mice or wild-type mice made arhythmic by exposure to constant light) were obese prone. Adipose tissue explants obtained from high-fat-fed mice have their own periodicity that was longer than animals on a chow diet. CONCLUSIONS: This study provides rigorous documentation for a circadian rhythm of insulin action and demonstrates that disturbing the natural rhythmicity of insulin action will disrupt the rhythmic internal environment of insulin sensitive tissue, thereby predisposing the animals to insulin resistance and obesity.


Subject(s)
Circadian Rhythm , Insulin Resistance , Insulin/blood , Obesity/etiology , ARNTL Transcription Factors/genetics , ARNTL Transcription Factors/metabolism , Animals , Diet, High-Fat/adverse effects , Glucose Clamp Technique , Male , Mice , Mice, Knockout
17.
Thromb Haemost ; 107(4): 726-34, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22234747

ABSTRACT

Platelet aggregometry and dense granule adenosine triphosphate (ATP) release assays are helpful to diagnose platelet disorders. Some laboratories simultaneously measure aggregation and ATP release using Chronolume® a commercial reagent containing D-luciferin, firefly luciferase and magnesium. Chronolume® can potentiate sub-maximal aggregation responses, normalising canine platelet disorder findings. We investigated if Chronolume® potentiates human platelet aggregation responses after observing discrepancies suspicious of potentiation. Among patients simultaneously tested by light transmission aggregometry (LTA) on two instruments, 18/43 (42%), including 14/24 (58%) with platelet disorders, showed full secondary aggregation with one or more agonists only in tests with Chronolume®. As subjects with Quebec platelet disorder (QPD) did not show the expected absent secondary aggregation responses to epinephrine in tests with Chronolume®, the reason for the discrepancy was investigated using samples from 10 QPD subjects. Like sub-threshold ADP (0.75 µM), Chronolume® significantly increased QPD LTA responses to epinephrine (p<0.0001) and it increased both initial and secondary aggregation responses, leading to dense granule release. This potentiation was not restricted to QPD and it was mimicked adding 1-2 mM magnesium, but not D-luciferin or firefly luciferase, to LTA assays. Chronolume® potentiated the ADP aggregation responses of QPD subjects with a reduced response. Furthermore, it increased whole blood aggregation responses of healthy control samples to multiple agonists, tested at concentrations used for the diagnosis of platelet disorders (p values <0.05). Laboratories should be aware that measuring ATP release with Chronolume® can potentiate LTA and whole blood aggregation responses, which alters findings for some human platelet disorders, including QPD.


Subject(s)
Adenosine Triphosphate/metabolism , Factor V Deficiency/blood , Platelet Aggregation , Adenosine Diphosphate/chemistry , Benzothiazoles/metabolism , Blood Platelets/metabolism , Case-Control Studies , Epinephrine/chemistry , Factor V Deficiency/metabolism , Humans , Indicators and Reagents/pharmacology , Light , Luciferases/metabolism , Magnesium/metabolism , Platelet Aggregation Inhibitors/pharmacology , Platelet Function Tests/methods , Time Factors
18.
Article in English | MEDLINE | ID: mdl-21513567

ABSTRACT

Epistaxis is an important otorhinolaryngological emergency, which usually has an apparent etiology, frequently local trauma in children. Here we present a case report wherein the epistaxis was recalcitrant, and proved to have a psychiatric disorder as an underlying basis. The child was diagnosed with Attention Deficit/Hyperactivity Disorder, hyperactive type, which led to trauma to nasal mucosa due to frequent and uncontrolled nose picking. Treatment with atomoxetine controlled the patient's symptoms and led to a remission of epistaxis.

19.
Eur J Immunol ; 40(8): 2296-307, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20468007

ABSTRACT

Regulation of adaptive immunity by innate immune cells is widely accepted. Conversely, adaptive immune cells can also regulate cells of the innate immune system. Here, we report for the first time the essential role of B cells in regulating macrophage (Mφ) phenotype. In vitro B cell/Mφ co-culture experiments together with experiments in transgenic mice models for B-cell deficiency or overexpression showed B1 cells to polarize Mφ to a distinct phenotype. This was characterized by downregulated TNF-α, IL-1ß and CCL3, but upregulated IL-10 upon LPS stimulation; constitutive expression of M2 Mφ markers (e.g. Ym1, Fizz1) and overexpression of TRIF-dependent cytokines (IFN-ß, CCL5). Mechanistically, this phenotype was linked to a defective NF-κB activation, but a functional TRIF/STAT1 pathway. B1-cell-derived IL-10 was found to be instrumental in the polarization of these Mφ. Finally, in vivo relevance of B1-cell-induced Mφ polarization was confirmed using the B16 melanoma tumor model where adoptive transfer of B1 cells induced an M2 polarization of tumor-associated Mφ. Collectively, our results define a new mechanism of Mφ polarization wherein B1 cells play a key role in driving Mφ to a unique, but M2-biased phenotype. Future studies along these lines may lead to targeting of B1 cells to regulate Mφ response in inflammation and cancer.


Subject(s)
Antigens, Differentiation/metabolism , B-Lymphocytes/metabolism , Cell Differentiation , Cytokines/biosynthesis , Macrophages/metabolism , Adaptive Immunity , Adaptor Proteins, Vesicular Transport/metabolism , Adoptive Transfer , Animals , Antigens, Differentiation/genetics , B-Lymphocytes/immunology , B-Lymphocytes/pathology , B-Lymphocytes/transplantation , Cell Communication/immunology , Cell Differentiation/immunology , Coculture Techniques , Cytokines/genetics , Immunity, Innate , Macrophages/immunology , Macrophages/pathology , Melanoma, Experimental , Mice , Mice, Transgenic , NF-kappa B/metabolism , Transcriptional Activation
20.
J Thromb Haemost ; 7(4): 685-92, 2009 Apr.
Article in English | MEDLINE | ID: mdl-19175495

ABSTRACT

BACKGROUND: Multimerin 1 (MMRN1) is a large, homopolymeric adhesive protein, stored in platelets and endothelium, that when released, binds to activated platelets, endothelial cells and the extracellular matrix. OBJECTIVES: The goals of our study were to determine if (i) MMRN1 supports adhesion of resting and/or activated platelets under conditions of blood flow, and (ii) if MMRN1 enhances platelet adhesion to types I and III collagen. PATIENTS/METHODS: Platelet adhesion was evaluated using protein-coated microcapillaries, with or without added adhesive proteins and receptor antibodies. Platelets from healthy controls, Glanzmann thrombasthenia (GT) and severe von Willebrand factor (VWF)-deficient donors were tested. RESULTS: MMRN1 supported the adhesion of activated, but not resting, washed platelets over a wide range of shear rates. At low shear (150 s(-1)), this adhesion was supported by integrins alphavbeta3 and glycoprotein (GP) Ibalpha but it did not require integrins alphaIIbbeta3 or VWF. At high shear (1500 s(-1)), adhesion to MMRN1 was supported by beta3 integrin-independent mechanisms, involving GPIbalpha and VWF, that did not require platelet activation when VWF was perfused over MMRN1 prior to platelets. MMRN1 bound to types I and III collagen, independent of VWF, however, its enhancing effects on platelet adhesion to collagen at high shear were VWF dependent. CONCLUSIONS: MMRN1 supports platelet adhesion by VWF-dependent and -independent mechanisms that vary by flow rate. Additionally, MMRN1 binds to, and enhances, platelet adhesion to collagen. These findings suggest that MMRN1 could function as an adhesive ligand that promotes platelet adhesion at sites of vascular injury.


Subject(s)
Blood Platelets/physiology , Blood Proteins/metabolism , Platelet Adhesiveness , Receptors, Cell Surface/metabolism , von Willebrand Factor/metabolism , Case-Control Studies , Collagen Type I/metabolism , Collagen Type III/metabolism , Humans , Perfusion , Thrombasthenia/blood , von Willebrand Diseases/blood
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