Platelets modulate the proteolysis of factor VIII:C protein by plasmin

Factor VIII coagulant protein (VIII:C) functions as a critical cofactor with factor IXa, calcium ions, and phospholipid during the activation of factor X. In the course of this reaction, the activity of VIII:C is first increased and then is destroyed by one or more serine proteases that are part of the coagulation sequence. In this study, we have investigated the influence of platelets on the inactivation of VIII:C by plasmin. Platelets were separated from plasma proteins in the presence of granule release inhibitors and were incubated with plasmin and isolated VIII:C or the complex of purified VIII:C/von Willebrand factor (vWF); VIII:C activity and antigen levels were assessed over time. In the presence of platelets, the isolated VIII:C showed an initial increase in VIII:C activity that was not present when platelets were absent, and the VIII:C/vWF showed an increase in VIII:C activity over that seen when platelets were absent. In addition, platelets stabilized VIII:C activity over a one-hour time course when compared with buffer. The VIII:C antigen did not increase and decreased slowly whether platelets were present or absent. Preincubating the platelets with ristocetin, collagen, or plasmin did not alter the results, and experiments using platelets from a patient with severe von Willebrand's disease also showed a pattern similar to that seen with normal platelets. Experiments using fixed platelets or phospholipid vesicles showed that they did not support the activation reaction or delay the inactivation reaction. These studies demonstrate that platelets modulate the activation and inactivation of VIII:C by plasmin, apparently by a mechanism that is independent of the platelet release reaction.     

Salbutamol in acute organophosphorus insecticide poisoning – a pilotdose-response phase II study

Background: Treatment of acute organophosphorus (OP) insecticide poisoning is difficult, with many patients dying despite best care. Pre-clinical studies have shown benefit from salbutamol, possibly due speeding alveolar fluid clearance or reducing bronchoconstriction. In this small pilot dose-response study, we aimed to explore whether addition of nebulized salbutamol to standard care might improve resuscitation.

Methods: We performed a single-blind phase II study comparing the effect of two different doses of nebulized salbutamol versus saline placebo, in addition to standard treatment. Primary outcome was oxygen saturations over the first 60?min of resuscitation; secondary outcomes included heart rate, incidence of dysrhythmias, time to ‘atropinization’, atropine dose required, and mortality.

Result: Seventy-five patients were randomized to receive 5?mg (Salb5, n?=?25) or 2.5mg (Salb2.5, n?=?25) of salbutamol, or saline placebo (NoSalb, n?=?25), by nebulizer. Oxygen saturations did not differ between groups over the first 60?min of resuscitation (median AUC NoSalb: 1376 [95% CI 1282 to 1470], Salb2.5: 1395 [1305 to 1486], Salb5: 1233 [1100 to 1367]; p?=?.9898). Heart rate was also similar across the three arms. Median time to full atropinization, and atropine dose required, were the same for all three arms (NoSalb 15.0 [10–16] min and 12.6 [8.0–13.4] mg, Salb2.5 15.0 [10–16] min and 12.6 [9.3–16.8] mg, and Salb5 15.0 [10–20] min and 12.6 [10.7–20.6] mg; p?=?.4805 and p?=?.1871, respectively). Three (12%) patients died in the Salb2.5 and Salb5 groups and two (8%) in the NoSalb group.

Conclusion: This pilot study, within the limitations of its small size and variation between patients, found no apparent evidence that administration of nebulized salbutamol improved resuscitation of patients with acute OP insecticide self-poisoning. The data obtained provides a basis to design further studies to ultimately test the role of salbutamol in OP insecticide poisoning.     

Step On It! Impact of a Workplace New York City Taxi Driver Health Intervention to Increase Necessary Health Care Access

Objectives. We describe the impact of the Step On It! intervention to link taxi drivers, particularly South Asians, to health insurance enrollment and navigate them into care when necessary.Methods. Step On It! was a worksite initiative held for 5 consecutive days from September 28 to October 2, 2011, at John F. Kennedy International Airport in New York City. Data collected included sociodemographics, employment, health care access and use, height, weight, blood pressure, and random plasma glucose. Participants were given their results, counseled by a medical professional, and invited to participate in free workshops provided by partner organizations.Results. Of the 466 drivers participated, 52% were uninsured, and 49% did not have a primary care provider. Of 384 drivers who had blood pressure, glucose, or both measured, 242 (63%) required urgent or regular follow-up. Of the 77 (32%) requiring urgent follow-up, 50 (65%) sought medical care at least once, of whom 13 (26%) received a new diagnosis. Of the 165 (68%) requiring regular follow-up, 68 (41%) sought medical care at least once, of whom 5 (7%) received a new diagnosis.Conclusions. This study provides encouraging results about the potential impact of an easy-to-deliver, easily scalable workplace intervention with a large, vulnerable population.New York City alone has more than 50 000 yellow taxi drivers and a similar number of livery drivers.1 A large majority, 94%, are immigrants, mainly originating from India, Bangladesh, Pakistan, Haiti, and West African countries.1 Taxi drivers are often at greater risk for cardiovascular disease (CVD) and associated risk factors than the general population.2,3 Studies looking exclusively at taxi drivers have found a correlation between the occupation and myocardial infarctions, multivessel disease, obesity, insulin resistance, high blood pressure, high triglycerides, and high low-density lipoproteins.3 By nature of their occupation, drivers have a sedentary lifestyle.4,5 Sedentariness in the general population has been linked to a higher CVD mortality rate, secondary to coronary heart disease, sudden heart failure, hypertension, and diabetes.6–11 Environmental exposures are also to blame for high CVD and lung cancer risk for taxi drivers. Exposure to particulate matter, which is often found at high levels in closed vehicles, has been linked to lower heart rate variability, a predictor of CVD, and to lung cancer.12–14Other factors, such as high stress, poor working conditions, long hours, unstable income, unhealthy diet, significant concern about personal safety on the job, and institutional and organizational barriers further contribute to poorer health among taxi drivers.5,15–17 Several reports and studies on the working and living conditions of taxi drivers have been released in California; Chicago, Illinois; and New York City and described similar health profiles for this population.5,15,16 In New York City, drivers typically work 10- to 12-hour shifts 6 days a week.4,16,18 Studies have also shown that a major systems-level obstacle for taxi drivers is lack of adequate health care; 60% of taxi drivers were found to be uninsured in a Chicago study19 and 52% in a New York City study.20 The occupation-related barriers to care experienced by this largely immigrant community are further exacerbated by literacy and language barriers, financial pressures, family obligations, and cultural values.4,19,21 South Asian taxi drivers, the largest group of yellow taxi drivers in New York City, potentially face a double burden for CVD because of both the nature of their occupation and the increased CVD risk associated with South Asian ethnicity.22–27Several studies have demonstrated the successful use of occupation-based interventions to effect lifestyle changes.17,28–31 A literature review of dietary promotion programs in the workplace demonstrated that, with industry cooperation and use of a social–ecological model of intervention, worksite interventions can have gradual and favorable results.17 In one social–ecological study, changes to workplace cafeteria food service in conjunction with behavioral interventions for workers resulted in a significant increase in fruit and vegetable consumption among participants.17 Support from workplace management was crucial for the success of this program.17 Although a paucity of data exist on interventions specifically for US taxi drivers, a number of European studies have had good results for exercise and diet interventions for taxi and other drivers.29–31 A British pilot study used a peer video to encourage drivers to make healthy lifestyle changes over a 1-year study period, resulting in 73% of participating drivers reporting a significant lifestyle change, with greater physical activity, positive diet changes, and more time spent on family activities.29 Another British study used a peer education model for CVD risk education. Peer “health champions” disseminated information about free screenings and medical referrals; more than 66% of those who received medical appointments at screenings subsequently attended them.30 In Sweden, a healthy eating workplace intervention conducted at rest stops resulted in improved nutritional balance in meal choices among truck drivers.31 The results of these studies suggest that the workplace can be an effective setting for taxi driver health interventions in the United States.28The Immigrant Health and Cancer Disparities Service (IHCD) at Memorial Sloan-Kettering Cancer Center designed and implemented a taxi driver workplace health intervention, Step On It!, in 2011 at the John F. Kennedy (JFK) International Airport yellow cab holding lot in New York City. The Step On It! intervention incorporates specific components addressing drivers’ barriers to care, including

1. health insurance enrollment education and enrollment assistance to address lack of health insurance;
2. referrals to low-cost or free health clinics and hospitals to address financial barriers to obtaining health insurance;
3. referrals to culturally and linguistically appropriate care to address language and cultural barriers;
4. events held during work hours, providing a window of opportunity, and assistance with finding clinics with flexible hours, to address drivers’ long work hours; and
5. onsite health screening and counseling with triage to urgent or regular follow-up to address lack of knowledge related to current health status and need for care.

After drivers were assessed for health care access and utilization, medical history, and CVD risk factors; screened for hypertension and elevated random plasma glucose; and measured for body mass index (BMI), Step On It! used a health care access navigation and case management intervention to link drivers to health insurance enrollment and navigate them into care when necessary. We describe the impact of this intervention on the primary outcome of interest, drivers’ engagement in needed medical care.     

Assessing the Biodiversity of Wood Decay Fungi in Northern Forests of Iran

Fungal diversity in the Hyrcanian forests can greatly vary due to diverse ecological conditions. The scope of the present research was to investigate the diversity of wood decay fungi at three sites in the northern forests of Iran. Fruiting bodies of fungi were collected in three plots dominated by Quercus castaneifolia C.A.M. (oak) and Carpinus betulus L. (hornbeam) in the Hyrcanian Forest. As many as 19 and 13 taxa were found on hornbeam and oak, respectively. The identification of these fungi revealed Fomes fomentarius (L.) Fr. and Ganoderma lucidum (Curtis) P. Karst. as highly abundant on hornbeam and oak, respectively. Highest fungal abundance was observed at an altitude range of 1150-1200 meters above sea level. Diversity of macro-fungi was determined and the mean Shannon diversity index was found to be 2.52 and 1.94 for hornbeam and oak, respectively, and mean equitability was calculated as 0.84 and 0.73 for hornbeam and oak, respectively. There were no significant differences in the Shannon Diversity Index or equitability. Overall, current work showed that most of the identified fungi were classified as white rot fungi.     

Comparative study of time-course of hemodynamic effect of isosorbide dinitrate spray and sublingual tablets in patients with pulmonary congestion

Summary We compared the time-course of the hemodynamic effect of isosorbide dinitrate (ISDN), 5 mg, in the form of sublingual tablet and oral spray, in 15 patients with isolated chronic pulmonary congestion (pulmonary arterial end-diastolic pressure of 15 mmHg or more in the presence of normal or only slightly reduced cardiac index). Both formulations produced significant reductions in the pulmonary arterial end-diastolic pressure. The effect of ISDN tablet (sublingually) became evident at 10 minutes after administration and was maximal at 30 minutes. The effect of ISDN oral spray became evident at 3 minutes and reached a peak at 10 minutes. The magnitude of hemodynamic response was similar. These findings indicate that ISDN oral spray is superior to ISDN sublingual tablets for rapid relief of pulmonary congestion     

Infantile peripheral neuropathy,deafness, and proximal tubulopathy associated with a novel mutation of the RRM2B gene

Mitochondrial DNA depletion syndromes are a group of autosomal recessive hereditary disorders characterized by reduction of the amount of mitochondrial DNA in the affected tissue (muscle, liver, brain, or kidneys). We report a case of an infant with myopathy, deafness, peripheral neuropathy, nephrocalcinosis, proximal renal tubulopathy, moderate lactic acidosis, and a novel mutation of the RRM2B gene.Mitochondrial DNA depletion syndromes are a group of autosomal recessive hereditary disorders characterized by reduction of the mitochondrial DNA amount in the affected tissue (1). Depletion of mitochondrial DNA can affect specific tissues or combination of organs and tissues including muscles, liver, brain, or kidneys (2,3).Different defects of nuclear genes may lead to different clinical manifestations, such as hepatocerebral syndrome, encephalopathy, or myopathy. One of the recently identified genes for mitochondrial DNA depletion syndromes is RRM2B, which encodes an isoform of a small subunit of ribonucleotide reductase. This enzyme plays an essential role in nucleotide synthesis, converting ribonucleotides to deoxyribonucleotides. Since 2008, 14 mutations of RRM2B gene have been reported (3,4). All the reported mutations are unique and there is no mutation that appears in more than one family (1-4).All reported patients had myopathy and primary lactic acidosis. More than a half of them died before the fourth month of age. The oldest patient with RRM2B mutation was a 42 years old woman with clinical findings suggestive of neurogastrointestinal encephalopathy (5). In this report, we review a case of an infant with muscular hypotonia, myopathy, peripheral neuropathy, deafness, nephrocalcinosis, proximal renal tubulopathy, moderate lactic acidosis, and a novel mutation of the RRM2B gene.     

Identification of potential inhibitors of Zika virus NS5 RNA-dependent RNA polymerase through virtual screening and molecular dynamic simulations

Zika virus (ZIKV) is one of the mosquito borne flavivirus with several outbreaks in past few years in tropical and subtropical regions. The non-structural proteins of flaviviruses are suitable active targets for inhibitory drugs due to their role in pathogenicity. In ZIKV, the non-structural protein 5 (NS5) RNA-Dependent RNA polymerase replicates its genome. Here we have performed virtual screening to identify suitable ligands that can potentially halt the ZIKV NS5 RNA dependent RNA polymerase (RdRp). During this process, we searched and screened a library of ligands against ZIKV NS5 RdRp. The selected ligands with significant binding energy and ligand-receptor interactions were further processed. Among the selected docked conformations, top five was further optimized at atomic level using molecular dynamic simulations followed by binding free energy calculations. The interactions of ligands with the target structure of ZIKV RdRp revealed that they form strong bonds within the active sites of the receptor molecule. The efficacy of these drugs against ZIKV can be further analyzed through in-vitro and in-vivo studies.     

Hematopoietic growth factor expression and ATRA sensitivity in acute promyelocytic blast cells

Acute promyelocytic leukemia (APL) is a homogeneous subgroup of acute myeloid leukemias (AMLs) characterized by the presence of the t(15,17) translocation and the resulting promyelocytic myeloid leukemia/retinoic acid receptor alpha (PML/RAR alpha) fusion proteins. To date APL is the only AML that is sufficiently sensitive to all-trans retinoic acid's (ATRA) differentiating effect. In vivo ATRA alone achieves complete remission in most APL patients. However, failure or partial responses are observed and the molecular basis of the absence of ATRA response in these patients has not been determined. To gain insights in the cell growth and differentiation of APL cells, expression of hematopoietic growth factors (HGF) shown to be produced by leukemic cells (interleukin-1 beta [IL-1 beta], IL-6, tumor necrosis factor alpha (TNF alpha), granulocyte colony-stimulating factor [G-CSF], granulocyte- macrophage colony-stimulating factor [GM-CSF], and IL-3) was studied in 16 APL samples. Twelve APL cases expressed IL-1 beta, IL-6, and TNF alpha, but not G-CSF, GM-CSF, and IL-3. These cases achieved complete remission with ATRA therapy. The four remaining patients (either TNF alpha negative or G-CSF, GM-CSF or IL-3 positive) did not achieve complete remission with ATRA. In all cases, in vivo response to ATRA therapy was correlated to the in vitro differentiation effect of all- trans retinoic acid 10(-6) mol/L. Thus, ATRA differentiation induction was strongly correlated to the HGF expression (P < .0001). These results suggest that the presence or absence of HGF's expression by APL cells may contribute to the therapeutic effect of ATRA in this disease.     

Biological evaluation of intervertebral disc cells in different formulations of gellan gum‐based hydrogels

Gellan gum (GG)‐based hydrogels are advantageous in tissue engineering not only due to their ability to retain large quantities of water and provide a similar environment to that of natural extracellular matrix (ECM), but also because they can gelify in situ in seconds. Their mechanical properties can be fine‐tuned to mimic natural tissues such as the nucleus pulposus (NP). This study produced different formulations of GG hydrogels by mixing varying amounts of methacrylated (GG‐MA) and high‐acyl gellan gums (HA‐GG) for applications as acellular and cellular NP substitutes. The hydrogels were physicochemically characterized by dynamic mechanical analysis. Degradation and swelling abilities were assessed by soaking in a phosphate buffered saline solution for up to 170 h. Results showed that as HA‐GG content increased, the modulus of the hydrogels decreased. Moreover, increases in HA‐GG content induced greater weight loss in the GG‐MA/HA‐GG formulation compared to GG‐MA hydrogel. Potential cytotoxicity of the hydrogel was assessed by culturing rabbit NP cells up to 7 days. An MTS assay was performed by seeding rabbit NP cells onto the surface of 3D hydrogel disc formulations. Viability of rabbit NP cells encapsulated within the different hydrogel formulations was also evaluated by Calcein‐AM and ATP assays. Results showed that tunable GG‐MA/HA‐GG hydrogels were non‐cytotoxic and supported viability of rabbit NP cells. Copyright © 2012 John Wiley & Sons, Ltd.