The ubiquitous microtubule-associated protein 4 (MAP4) controls organelle distribution by regulating the activity of the kinesin motor.

Regulation of organelle transport by molecular motors along the cytoskeletal microtubules is central to maintaining cellular functions. Here, we show that the ubiquitous tau-related microtubule-associated protein 4 (MAP4) can bias the bidirectional transport of organelles toward the microtubule minus-ends. This is concurrent with MAP4 phosphorylation, mediated by the kinase GSK3ß. We demonstrate that MAP4 achieves this bias by tethering the cargo to the microtubules, allowing it to impair the force generation of the plus-end motor kinesin-1. Consistent with this mechanism, MAP4 physically interacts with dynein and dynactin and, when phosphorylated, associates with the cargo-motor complex through its projection domain. Its phosphorylation coincides with the perinuclear accumulation of organelles, a phenotype that is rescued by abolishing the cargo-microtubule MAP4 tether or by the pharmacological inhibition of dynein, confirming the ability of kinesin to inch along, albeit inefficiently, in the presence of phosphorylated MAP4. These findings have broad biological significance because of the ubiquity of MAP4 and the involvement of GSK3ß in multiple diseases, more specifically in cancer, where the MAP4-dependent redistribution of organelles may be prevalent in cancer cells, as we demonstrate here for mitochondria in lung carcinoma epithelial cells.

Combined cardiac anomalies in Noonan syndrome: A case report.

INTRODUCTION: Noonan syndrome is the second most common syndromic cause of congenital heart disease. Most patients have an autosomal dominant inheritance, but some cases may be sporadic. Pulmonary stenosis is the most common cardiac manifestation in Noonan syndrome, associated with the atrial septal defect and hypertrophic cardiomyopathy. A combination of these three is present only in 5% of patients. PRESENTATION OF CASE: We report a case of a 21-year-old female who presented to our hospital concomitant cardiac lesions associated with pulmonary stenosis, atrial septal defect, and hypertrophic cardiomyopathy. This combination of cardiac defects is an infrequent manifestation of Noonan syndrome. The patient presented with complaints of exertion syncope over the past two years. 2D-Echocardiography showed biventricular hypertrophy, dysplastic pulmonary valve, severe pulmonary stenosis, asymmetric septal hypertrophy and large atrial septal defect. The genetic analysis report showed autosomal dominant inheritance with Ras/MAPK (mitogen-activated protein kinase) Positive. DISCUSSION: Due to the wide spectrum of symptoms and presentations in Noonan cases, accurate clinical and genetic diagnosis, and comprehensive management of the disorder are strongly recommended. CONCLUSION: We have described a case of rare combination of cardiovascular defects in Noonan Syndrome with a view to achieve better insight into the disease course and advantages of timely treatment and follow up. Our patient is currently in follow-up after treatment with percutaneous balloon pulmonary valvuloplasty, has improved symptoms, and is awaiting heart transplant.

Rare case of aortic aneurysm with type A dissection (extending to right coronary artery) and severe AR in a nonhypertensive and non pregnant female.

INTRODUCTION: Typically a patient with acute aortic dissection presents with severe chest pain radiating to the back, tearing in nature. Rarely it can present as painless acute aortic dissection this is seen in iatrogenic cases or when associated with atherosclerosis, diabetes, or aortic aneurysm. CASE PRESENTATION: We hereby present a case of a 32-year aged female who presented with dyspnoea & palpitations (NYHA III) from last 6 months, diagnosed to have Aortic Aneurysm with Type A dissection & Severe AR. She eventually underwent BENTALL'S procedure with CABG and had an uneventful recovery. DISCUSSION: Clinical manifestation of Aortic dissection can be variable, therefore its diagnosis is challenging. 25% of cases, may have associated ECG changes suggestive of acute coronary syndrome leading to a possible misdiagnosis especially if associated ST elevation in ECG. Aorto arteritis is a non-atherosclerotic chronic inflammatory vascular disease of unknown etiology that affects the aorta, proximal parts of its major branches. In this case, there is a possibility that there was underlying spontaneous coronary artery dissection which in turn could be cause for silent ischemia in young women. CONCLUSION: Acute aortic dissection is a life-threatening disease with a high rate of cardiovascular morbidity and mortality. The most important and common risk factor is systemic hypertension which has been reported in the 70% of the patients with aortic dissection. Most of the aortic dissection observed in young women has been reported to be related to pregnancy. Dissection should be suspected during any acute coronary syndrome, particularly Inferior wall MI.

Regulation of in vivo dynein force production by CDK5 and 14-3-3ε and KIAA0528.

Single-molecule cytoplasmic dynein function is well understood, but there are major gaps in mechanistic understanding of cellular dynein regulation. We reported a mode of dynein regulation, force adaptation, where lipid droplets adapt to opposition to motion by increasing the duration and magnitude of force production, and found LIS1 and NudEL to be essential. Adaptation reflects increasing NudEL-LIS1 utilization; here, we hypothesize that such increasing utilization reflects CDK5-mediated NudEL phosphorylation, which increases the dynein-NudEL interaction, and makes force adaptation possible. We report that CDK5, 14-3-3ε, and CDK5 cofactor KIAA0528 together promote NudEL phosphorylation and are essential for force adaptation. By studying the process in COS-1 cells lacking Tau, we avoid confounding neuronal effects of CDK5 on microtubules. Finally, we extend this in vivo regulatory pathway to lysosomes and mitochondria. Ultimately, we show that dynein force adaptation can control the severity of lysosomal tug-of-wars among other intracellular transport functions involving high force.

A posttranslational modification of the mitotic kinesin Eg5 that enhances its mechanochemical coupling and alters its mitotic function.

Numerous posttranslational modifications have been described in kinesins, but their consequences on motor mechanics are largely unknown. We investigated one of these-acetylation of lysine 146 in Eg5-by creating an acetylation mimetic lysine to glutamine substitution (K146Q). Lysine 146 is located in the α2 helix of the motor domain, where it makes an ionic bond with aspartate 91 on the neighboring α1 helix. Molecular dynamics simulations predict that disrupting this bond enhances catalytic site-neck linker coupling. We tested this using structural kinetics and single-molecule mechanics and found that the K146Q mutation increases motor performance under load and coupling of the neck linker to catalytic site. These changes convert Eg5 from a motor that dissociates from the microtubule at low load into one that is more tightly coupled and dissociation resistant-features shared by kinesin 1. These features combined with the increased propensity to stall predict that the K146Q Eg5 acetylation mimetic should act in the cell as a "brake" that slows spindle pole separation, and we have confirmed this by expressing this modified motor in mitotically active cells. Thus, our results illustrate how a posttranslational modification of a kinesin can be used to fine tune motor behavior to meet specific physiological needs.

Heterogeneity in kinesin function.

The kinesin family proteins are often studied as prototypical molecular motors; a deeper understanding of them can illuminate regulation of intracellular transport. It is typically assumed that they function identically. Here we find that this assumption of homogeneous function appears incorrect: variation among motors' velocities in vivo and in vitro is larger than the stochastic variation expected for an ensemble of "identical" motors. When moving on microtubules, slow and fast motors are persistently slow, and fast, respectively. We develop theory that provides quantitative criteria to determine whether the observed single-molecule variation is too large to be generated from an ensemble of identical molecules. To analyze such heterogeneity, we group traces into homogeneous sub-ensembles. Motility studies varying the temperature, pH and glycerol concentration suggest at least 2 distinct functional states that are independently affected by external conditions. We end by investigating the functional ramifications of such heterogeneity through Monte-Carlo multi-motor simulations.

Aortoiliac reconstruction in the setting of in-stent restenosis.

Complex iliac artery obstructions, particularly bilateral stenosis or total iliac artery occlusions, are usually treated with aortofemoral or aortobifemoral graft surgery. However, surgical treatment is associated with 3% mortality rate and significant morbidity such as intestinal ischemia, spinal cord injury, and ureteral damage. Percutaneous interventions of aortic bifurcation offer a promising alternative to surgery with potentially lower morbidity and mortality risk. We report a case of peripheral artery disease who had underwent right transfemoral iliac angioplasty with femoropopliteal bypass presented again with bilateral lower limb ischemia, who was successfully treated with stent implantation with the kissing balloon technique.

Axonal Transport: A Constrained System.

Long-distance intracellular axonal transport is predominantly microtubule-based, and its impairment is linked to neurodegeneration. Here we review recent theoretical and experimental evidence that suggest that near the axon boundaries (walls), the effective viscosity can become large enough to impede cargo transport in small (but not large) caliber axons. Theoretical work suggests that this opposition to motion increases rapidly as the cargo approaches the wall. However, having parallel microtubules close enough together to enable a cargo to simultaneously engage motors on more than one microtubule dramatically enhances motor activity, and thus decreases the effects due to such opposition. Experimental evidence supports this hypothesis: in small caliber axons, microtubule density is higher, increasing the probability of having parallel microtubules close enough that they can be used simultaneously by motors on a cargo. For transport toward the minus-end of microtubules, e.g., toward the cell body in an axon, a recently discovered force adaptation system can also contribute to overcoming such opposition to motion.

Load-induced enhancement of Dynein force production by LIS1-NudE in vivo and in vitro.

Most sub-cellular cargos are transported along microtubules by kinesin and dynein molecular motors, but how transport is regulated is not well understood. It is unknown whether local control is possible, for example, by changes in specific cargo-associated motor behaviour to react to impediments. Here we discover that microtubule-associated lipid droplets (LDs) in COS1 cells respond to an optical trap with a remarkable enhancement in sustained force production. This effect is observed only for microtubule minus-end-moving LDs. It is specifically blocked by RNAi for the cytoplasmic dynein regulators LIS1 and NudE/L (Nde1/Ndel1), but not for the dynactin p150(Glued) subunit. It can be completely replicated using cell-free preparations of purified LDs, where duration of LD force production is more than doubled. These results identify a novel, intrinsic, cargo-associated mechanism for dynein-mediated force adaptation, which should markedly improve the ability of motor-driven cargoes to overcome subcellular obstacles.

Catheter-Directed Thrombolysis Is a Safe and Alternative Therapeutic Approach in the Management of Postpartum Lower Limb Deep Venous Thrombosis.

Deep vein thrombosis (DVT) is a major health problem in pregnancy and postpartum period. Catheter-directed thrombolysis (CDT) is safe and effective in management of symptomatic DVT. Value of CDT in postpartum DVT is not fully evaluated. We describe five patients presenting with acute iliofemoral DVT in their early postpartum period who were treated with mechanical thromboaspiration and CDT. The CDT was done using streptokinase infusion and unfractionated heparin. Percutaneous angioplasty was done in patients with symptomatic residual lesion following thrombolysis. Patients were discharged with oral anticoagulant and compression stockings. This approach was successful in all four cases. Percutaneous endovascular therapy using CDT, mechanical thromboaspiration, and balloon angioplasty is safe and effective in iliofemoral DVT in postpartum period.

Anti-Plaque Efficacy of Herbal and 0.2% Chlorhexidine Gluconate Mouthwash: A Comparative Study.

BACKGROUND: Mouthwashes are an adjunct to, not a substitute for, regular brushing and flossing. Chlorohexidine is cationic bis-biguanide broad spectrum antiseptic with both anti-plaque and antibacterial properties. It has side-effects like brownish discoloration of teeth and dorsum of the tongue, taste perturbation, oral mucosal ulceration, etc. To compare the antiplaque efficacy of herbal and chlorohexidine gluconate mouthwash. MATERIALS AND METHODS: A double-blinded parallel, randomized controlled clinical trial was conducted in the Department of Periodontics, MNR Dental College. Totally 100 preclinical dental students were randomized into three groups (0.2% chlorohexidine, Saline and herbal mouthwash). All the groups were made to refrain from their regular mechanical oral hygiene measures and were asked to rinse with given respective mouthwashes for 4 days. The gingival and plaque scores are evaluated on 1(st) day, and 5(th) day, and differences were compared statistically. RESULTS: There was no significant difference in the gingival index (GI) and plaque index (PI) scores of the pre-rinsing scores of three groups and mean age of subjects in the three age groups, suggesting selected population for the three groups was homogenous. Mean GI and PI scores at the post rinsing stage were least for the Group A, followed by B and C. The difference of post rinsing PI and GI scores between Group A and Group B were statistically non-significant, which means anti-gingivitis and plaque inhibiting properties are similar for both. CONCLUSION: Within the limitations of this study chlorhexidine gluconate and herbal mouthwash (Hiora) showed similar anti plaque activity with latter showing no side effects.

AMPK activation promotes lipid droplet dispersion on detyrosinated microtubules to increase mitochondrial fatty acid oxidation.

Lipid droplets (LDs) are intracellular organelles that provide fatty acids (FAs) to cellular processes including synthesis of membranes and production of metabolic energy. While known to move bidirectionally along microtubules (MTs), the role of LD motion and whether it facilitates interaction with other organelles are unclear. Here we show that during nutrient starvation, LDs and mitochondria relocate on detyrosinated MT from the cell centre to adopt a dispersed distribution. In the cell periphery, LD-mitochondria interactions increase and LDs efficiently supply FAs for mitochondrial beta-oxidation. This cellular adaptation requires the activation of the energy sensor AMPK, which in response to starvation simultaneously increases LD motion, reorganizes the network of detyrosinated MTs and activates mitochondria. In conclusion, we describe the existence of a specialized cellular network connecting the cellular energetic status and MT dynamics to coordinate the functioning of LDs and mitochondria during nutrient scarcity.

Outcome of venous stenting following catheter directed thrombolysis for acute proximal lower limb venous thrombosis: a prospective study with venous Doppler follow-up at 1-year.

Functional outcome of venous stent placement for the management of acute iliofemoral deep vein thrombosis (DVT) following catheter-directed thrombolysis (CDT), remain undefined. The purpose of this study was to assess immediate and intermediate term outcomes among patients treated with venous stenting following CDT in patients with proximal lower limb DVT. Thirty consecutive patients aged between 20-70 years with proximal lower limb DVT formed the study group. The mean duration of CDT done with streptokinase was 4.5 ± 1.3 days. Patients with residual venous obstruction and/or large clot burden were treated further with venous angioplasty and/or stenting. Primary endpoint was to evaluate the safety, efficacy and patency of venous stenting in the management of incomplete result following CDT. After 12 months, post-thrombotic syndrome (PTS) was assessed clinically using Villalta scale and deep venous patency was assessed through duplex ultrasound. We studied 8 (5 female and 3 male) patients with 9 (3 left and 6 right) limb involvement and 13 stent (4 balloon expandable and 9 self expandable) placement. All patients improved clinically immediately following venous stenting. Technical success was achieved in all patients. One patient developed pulmonary embolism during course of hospital stay. One patient had stent thrombosis and PTS and another patient died due to carcinoma breast during follow-up. Deep venous stenting is an effective mode of treatment in proximal acute lower limb DVT with high late patency rate up to 1-year.

Percutaneous coronary intervention in a rare variety of single coronary artery.

We present a case of 50-year-old male having unstable angina. A rare type of single coronary artery was identified during the Coronary angiogram. The left anterior descending (LAD) and left circumflex artery (LCX) had originated from the proximal segment of right coronary artery along with significant lesion in LCX. Computed tomographic (CT) coronary angiogram confirmed the origin and course following which successful percutaneous coronary intervention (PCI) was done to LCX. The incidence of this type of coronary anomaly is 0.004%. We emphasize the importance of having a CT coronary angiogram to identify the course before the intervention. The procedural risk during PCI in patients with single coronary ostium is high. Moreover, the angulation and course of the culprit artery also pose a challenge. Good coaxial guide support by using an appropriate guiding catheter is the key to success.

Catheter-directed thrombolysis in management of postpartum lower limb deep venous thrombosis - A case series.

Deep vein thrombosis (DVT) is a major health problem in pregnancy and postpartum period. Catheter-directed thrombolysis (CDT) is safe and effective in the management of symptomatic DVT. Value of CDT in postpartum DVT is not fully evaluated. We describe five patients presenting with acute iliofemoral DVT in their early postpartum period who were treated with mechanical thromboaspiration and CDT. The CDT was done using streptokinase infusion and unfractionated heparin. Percutaneous angioplasty was done in patients with symptomatic residual lesion following thrombolysis. Patients were discharged with oral anticoagulant and compression stockings. This approach was successful in all five cases. Percutaneous endovascular therapy using CDT, mechanical thromboaspiration, and balloon angioplasty is safe and effective in iliofemoral DVT in postpartum period.

Thrombolysis With Single Bolus Tenecteplase Compared With Streptokinase Infusion in the Treatment of Acute Pulmonary Embolism: A Pilot Study.

OBJECTIVE: This study was planned to compare the efficacy of bolus regimens of tenecteplase (TNK) and 24 hours infusion of streptokinase (STK) in acute pulmonary embolism (APE) in a resource-poor setting. INTERVENTIONS: In all, 25 patients received injection of TNK, and 75 patients received infusion of STK over 24 hours. RESULTS: Pulmonary artery systolic pressure and right ventricular function were improved separately and significantly (P = .01) in both the study groups of patients from baseline at 24 hours or at seventh day and was comparable among the TNK and STK groups of patients. Mean duration of stay in intensive care unit was significantly less (2.2 ± 0.8 vs 3.2 ± 1.3 days; P = .04), and bleeding risk was also found to be nonsignificantly less in the TNK group. CONCLUSION: These results suggest that a 24-hour infusion regimen of STK is as effective as bolus TNK in the treatment of patients with APE in countries with limited resources.

Catheter-Directed Thrombolysis Along with Mechanical Thromboaspiration versus Anticoagulation Alone in the Management of Lower Limb Deep Venous Thrombosis-A Comparative Study.

Catheter-directed thrombolysis (CDT) with assisted mechanical thrombolysis is now considered as the standard of medical care for deep vein thrombosis (DVT). The study was conducted to describe the immediate and long-term (6 months) safety and effectiveness of CDT in patient with lower limb DVT compared with the routine anticoagulation alone. All 12 to 85 years old patients with recent (0-8 weeks) DVT were included. In CDT group, thrombus was aspirated mechanically and streptokinase (STK) was given along with unfractionated heparin (UFH). After 6 months, deep venous patency and postthrombotic syndrome (PTS) was assessed by using duplex ultrasound and Villalta scale, respectively. Among 51 patients with completed data, 25 patients were allocated additional CDT given for a mean duration of 108 ± 32 hours and 26 patients were allocated standard treatment alone. Grade III (complete) lysis was achieved in 37% patients and grade II (50-90%) lysis in 63% of patients. Patients with partial lysis underwent percutaneous transluminal angioplasty and/or venous stenting. After 6 months, iliofemoral patency was found in 20 (80%) in the CDT group versus 7 (23%) in anticoagulation alone group (p < 0.01). PTS was seen in 5 (20%) in the CDT group versus 19 (77%) in anticoagulation alone group (p < 0.01). We conclude that CDT and conventional manual aspiration thrombectomy are an effective treatment for lower extremity DVT. STK infusion can be safely given up to 6 days. As addition of UFH can cause thrombocytopenia, so daily monitoring of complete blood counts is needed during CDT.

Recurrent myocardial infarction in a case of congenital afibrinogenemia.

Afibrinogenemia is a rare autosomal recessive bleeding disorder with an estimated prevalence of 1:1,000,000. Usual presentation of this disorder is spontaneous bleeding, bleeding after minor trauma and excessive bleeding during interventional procedures. Paradoxically, few patients with afibrinogenemia may also suffer from severe thromboembolic complications. The management of these patients is particularly challenging because they are not only at risk of thrombosis but also of bleeding. We are presenting a case of 33-year-old male patient of congenital afibrinogenemia who had two episodes myocardial infarction in a span of two years. The patient was managed conservatively with antiplatelet therapy and thrombolytic therapy was not given due to high risk for bleeding.