Transoral resection of the odontoid

The odontoid process is located in a critical area of the spine and is part of a complex structure, the atlanto-axial junction. This C1-2 junction allows for a great deal of cervical mobility in planes of rotation, flexion, and extension. Lesions of the odontoid process and associated ligaments can result in compression of the brainstem, cervicomedullary junction, and spinal cord. Resultant symptoms include weakness, spasticity, lower cranial nerve palsies, including difficulty in swallowing, phonation disorders, Bell's cruciate paralysis, and breathing disorders. Patients with lesions in this area require a thorough neurological and otolaryngologic evaluation. The reducibility of the lesion needs to be determined as an operative prerequisite. Extensive multimodality radiographic imaging may be required pre-, intra-, and postoperatively. Transoral surgery of the odontoid is technically demanding and requires a thorough understanding of the relevant anatomy and pathology. Perioperative and intraoperative adjuncts such as the operating microscope, fluoroscopy, image guidance instruments, high-speed air drills, and somatosensory-evoked monitoring help to expedite the surgery and reduce the risk of complications. Postoperative instability must be assessed and treated. A team consisting of a spine surgeon, anesthesiologists, otolaryngologists, and critical care physicians skilled in managing patients with similar conditions may provide the best possible outcome for these patients. This article reviews the pertinent patient evaluation, imaging studies, surgical indications and techniques, and post-operative management.     

Inhibition of human non-pancreatic phospholipases A2 by retinoids and flavonoids. Mechanism of action

The interaction of retinoids and flavonoids with phospholipases A₂ (PLA₂) was studied to assess the mechanism of inhibition. Retinoids, such as retinal, retinol, retinoic acid and retinol acetate, and flavonoids, such as quercetin, rutin, morin and sciadopitysin, inhibit Ca²⁺-dependent PLA₂ activity of human synovial fluid (HSF)in vitro in a dose-dependent fashion; ID₅₀ s ranged from 2–8 M. Retinal inhibited neutral active Ca²⁺-dependent PLA₂s from human platelets, human plasma, human polymorphonuclear leukocytes andNaja mossambica mossambica venom in a dose-dependent manner while quercetin inhibits extracellular PLA₂ activities of human plasma, HSF andN. m. mossambica venon in a dose-dependent manner but not PLA₂ activity derived from human platelets and polymorphomonuclear leukocytes.Inhibition of PLA₂ activity by both flavonoid and retinoids were independent of Ca²⁺ or Na⁺. Increasing substrate concentration (9–144 nmols) relieved the inhibition of HSF-PLA₂ activity by quercetin indicating probable interaction with the substrate. The inhibition by retinal is independent of substrate concentration suggesting that inhibition by retinal is probably due to direct interaction with the enzyme. both retinal and quercetin quenched the relative fluorescent intensity ofN. m. mossambica PLA₂ and in a dose-dependent manner in the same concentration range at which they inhibitin vitro PLA₂ activity. Retinal and quercetin shift the thermotropic phase transition of distearoylphosphatidylethanolamine (DSPE) liposomes. Both compounds broadened the transition peak, shifted theT _m to lower temperature, and decreased enthalpy significantly. These findings indicate that inhibition of non-pancreatic human PLA₂s by retinoids and flavonoids can be mediated by interaction with enzyme and/or substrate.     

Optimization and evaluation of silk fibroin-chitosan freeze-dried porous scaffolds for cartilage tissue engineering application

Silk fibroin/chitosan blend has been reported to be an attractive biomaterial that provides a 3D porous structure with controllable pore size and mechanical property suitable for tissue engineering applications. However, there is no systematic study for optimizing the ratio of silk fibroin (SF) and chitosan (CS) which seems to influence the scaffold property to a great extent. The present research, therefore, investigates the effect of blend ratio of SF and CS on scaffold property and establishes the optimum value of blend ratio. Among the various blends, the scaffolds with blend ratio of SF/CS (80:20) were found to be superior. The scaffold possesses pore size in the range 71–210 μm and porosity of 82.2 ± 1.3%. The compressive strength of the scaffold was measured as 190 ± 0.2 kPa. The cell supportive property of the scaffold in terms of cell attachment, cell viability, and proliferation was confirmed by cell culture study using mesenchymal stem cells derived from umbilical cord blood. Furthermore, the assessment of glycosaminoglycan secretion on the scaffolds indicates its potentiality toward cartilage tissue regeneration.     

Oxidative injury and antioxidants in coronary artery bypass graft surgery: off-pump CABG significantly reduces oxidative stress

BACKGROUND: Coronary artery bypass grafting (CABG) can now be performed with or without cardiopulmonary bypass. The former entails global ischemia followed by reperfusion after declamping, whereas the latter does not. In view of growing evidence that reperfusion is associated with oxidative stress, we studied the extent of oxidative stress and antioxidant status in patients undergoing on-pump and off-pump CABG to determine whether the latter significantly reduces oxidative stress. METHODS: Thirty patients were initially enrolled for the study. The inclusion criteria included patients with atherosclerotic triple vessel disease, undergoing elective CABG, with good LV function, no major risk factors for surgery, with all biochemical investigations within normal limits, having stable angina and no history of previous infarct. Patients with valvular heart disease, ventricular aneurysm, heart failure and poor left ventricular function were excluded. These were alternately posted for on-pump and off-pump CABG. Eight patients were excluded as they developed unforeseen complications during the surgery. Out of the remaining 22 patients, 13 underwent off-pump CABG and 9 underwent on-pump CABG. Five blood samples were collected; baseline, 5, 15, 60 min and 24 h after reperfusion. Samples were analyzed for thiobarbituric acid reactive substances (TBARS), glutathione (G-SH) and catalase (CAT). The results were compared with their preanaesthetic levels in both the groups and also with 20 age- and sex-matched normal healthy individuals. RESULTS: Lipid peroxidation was significantly increased after reperfusion in patients undergoing on-pump CABG, maximum increase (p<0.0001) was seen 1 h after reperfusion, whereas off-pump CABG reduces oxidative stress. The G-SH levels were significantly decreased after reperfusion in on-pump and off-pump CABG patients, maximum decrease (p<0.0001) was seen 5 min after reperfusion in on-pump CABG. The catalase activity was significantly increased after reperfusion in on-pump and off-pump CABG patients, maximum increase (p<0.0001) was seen 1 h after reperfusion in on-pump CABG. CONCLUSION: Significant increase in oxidative stress was seen in patients undergoing on-pump CABG, whereas oxidative stress was less in off-pump CABG patients. The G-SH levels were decreased and Catalase activity was increased significantly in both on-pump and off-pump CABG patients.     

Budgeting for a billion: applying health technology assessment (HTA) for universal health coverage in India

Background

India recently launched the largest universal health coverage scheme in the world to address the gaps in providing healthcare to its population. Health technology assessment (HTA) has been recognised as a tool for setting priorities as the government seeks to increase public health expenditure. This study aims to understand the current situation for healthcare decision-making in India and deliberate on the opportunities for introducing HTA in the country.

Methods

A paper-based questionnaire, adapted from a survey developed by the International Decision Support Initiative (iDSI), was administered on the second day of the Topic Selection Workshop that was conducted as part of the HTA Awareness Raising Workshop held in New Delhi on 25–27 July, 2016. Participants were invited to respond to questions covering the need, demand and supply for HTA in their context as well as the role of their organisation vis-à-vis HTA. The response rate for the survey was about 68% with 41 participants having completed the survey.

Results

Three quarters of the respondents (71%) stated that the government allocated healthcare resources on the basis of expert opinion. Most respondents indicated reimbursement of individual health technologies and designing a basic health benefit package (93% each) were important health policy areas while medical devices and screening programmes were cited as important technologies (98% and 92%, respectively). More than half of the respondents noted that relevant local data was either not available or was limited. Finally, technical capacity was seen as a strength and a constraint facing organisations.

Conclusion

The findings from this study shed light on the current situation, the opportunities, including potential topics, and challenges in conducting HTA in India. There are limitations to the study and further studies may need to be conducted to inform the role that HTA will play in the design or implementation of universal health coverage in India.

     

The metalloprotease,NN-PF3 from <Emphasis Type="Italic">Naja naja</Emphasis> venom inhibits platelet aggregation primarily by affecting α2β1 integrin

NN-PF3 is a non-toxic, anticoagulant, high-molecular-mass (67.81 kDa) metalloprotease from Indian cobra (Naja naja) venom. In the present study, NN-PF3 was investigated for the mechanism of inhibition of collagen-induced aggregation of human platelets. The complete inhibition of collagen-induced aggregation and partial inhibition of ADP- and epinephrine-induced aggregation has the respective IC₅₀ of 75 ± 5, 185 ± 10, and 232 ± 12 nM, whereas no inhibition of thrombin-, arachidonic acid-, and ristocetin-induced aggregation of platelets was observed in platelet-rich plasma. Further, native NN-PF3 and EDTA-inactivated NN-PF3 inhibited collagen-induced aggregation of washed platelets with respective IC₅₀ of 75 ± 4 and 180 ± 6 nM. The higher inhibitory effect of native NN-PF3 compared with EDTA-inactivated NN-PF3 suggests the enzymatic and non-enzymatic mechanism of inhibition. NN-PF3 pretreatment affected the collagen binding but not the fibrinogen, and fibronectin binding of washed platelets in adhesion assay suggested that the collagen receptors are affected. Western blot study using anti-integrin α2β1 mAb 6F1 suggested that NN-PF3 binds to integrin α2β1 in a primary structure-dependent manner only and is not cleaved. There was a drastic reduction in the intensity of several intracellular signaling phosphotyrosine protein bands when monoclonal anti-phosphotyrosine antibody was used, suggesting that the major activation pathway of platelets get affected, which occurs through glycoprotein VI. NN-PF3 did not bind to collagen as revealed by Western blot using anti-collagen mAb. Furthermore, neither the proteolytic cleavage of fibrinogen nor its degradation products by NN-PF3 contributed for the collagen-induced platelet aggregation inhibition.