Acoustic monitoring (RFM) of total hip arthroplasty results of a cadaver study

Introduction

At present there are no reliable non-traumatic and non-invasive methods to analyse the healing process and loosening status after total hip replacement. Therefore early as well as late loosening of prosthesis and interface component problems are difficult to be found or diagnosed at any time.

Methods

In a cadaver study the potential application of Resonance Frequency Monitoring (RFM) will be evaluated as a non-invasive and non-traumatic method to monitor loosening and interface problems in hip replacement. In a 65 year old female cadaver different stability scenarios for a total hip replacement (shaft, head/modular head and cup, ESKA, Luebeck, Germany) are simulated in cemented and cement less prosthesis and then analysed with RFM. The types of stability vary from secure/press-fit to interface-shaft disruption.

Results

The RFM shows in cemented as well as cement less prosthesis significant intra-individual differences in the spectral measurements with a high dynamic (20 dB difference corresponding to the factor 100 (10000%)), regarding the simulated status of stability in the prosthesis system.

Conclusion

The results of the study demonstrate RFM as a highly sensitive non-invasive and non-traumatic method to support the application of RFM as a hip prosthesis monitoring procedure. The data obtained shows the possibility to use RFM for osteointegration surveillance and early detection of interface problems, but will require further evaluation in clinical and experimental studies.     

Long-term follow-up for superior vena cava filter placement

The short-term effectiveness and safety placement of superior vena cava (SVC) filter in the treatment of upper extremity deep venous thrombosis in patients with contraindication to anticoagulation have been well documented. However, as opposed to the numerous reported experiences with inferior vena cava filter placement and its complications, there has been no documented long-term follow-up on SVC filter placement. We, therefore, reviewed our experience with SVC filter placement. A retrospective review was performed of the 154 cases of patients who underwent SVC filter placement between January 1994 and August 2005 at our institution. Seven additional patients had unsuccessful SVC filter placement due to widespread deep venous thrombosis. The data were evaluated for both insertion complications (pneumothorax, hemorrhage, filter misplacement) and long-term complications (pulmonary embolism, migration, caval occlusion). The follow-up included review of serial chest radiographs to evaluate for filter migration in patients who lived at least 60 days after filter insertion and had chest radiography performed (n = 40), patients' charts, clinic visits, and telephone contacts, hospital databases, city death records, and national databases. There were 69 males and 85 females with a mean age of 73.6 years (range, 16-96 years; +/-15.3 [SD] years). Follow-up ranged from 1 day to 3750 days (256.3 +/- 576 days [mean +/- SD]) and 5 patients were lost to follow-up. Of the 154 patients, 58 survived longer than 60 days with mean follow-up of 628.4 days. All SVC filters (TrapEase, n = 38; Greenfield, n = 116) were successfully deployed in the 154 patients. During the follow-up, 114 (74.0% mortality) of the patients died of chronic illness or from cancer complications. There were three cases of pericardial tamponade (1.9%), and one case of misplaced filter in innominate vein. There were no known cases of symptomatic pulmonary embolism, caval occlusion, pneumothorax, or filter migration. SVC filter placement is associated with a low incidence of complications with long-term follow-up. These data help to reaffirm the safety and effectiveness of SVC filter placement. However, SVC perforation in young males remains a significant issue.     

219 vascular fellows' perception of the future of vascular surgery

In an attempt to identify the fellows' concerns about the future of the field of vascular surgery, we conducted a survey consisting of 22 questions at an annual national meeting in March from 2004 to 2007. In order to obtain accurate data, all surveys were kept anonymous. The fellows were asked (1) what type of practice they anticipated they would be in, (2) what the new training paradigm for fellows should be, (3) to assess their expectation of the needed manpower with respect to the demand for vascular surgeons, (4) what were major threats to the future of vascular surgery, (5) whether they had heard of and were in favor of the American Board of Vascular Surgery (ABVS), (6) who should be able to obtain vascular privileges, and (7) about their interest in an association for vascular surgical trainees. Of 273 attendees, 219 (80%) completed the survey. Males made up 87% of those surveyed, and 60% were between the ages of 31 and 35 years. Second-year fellows made up 82% of those surveyed. Those expecting to join a private, academic, or mixed practice made up 35%, 28%, and 20% of the respondents, respectively, with 71% anticipating entering a 100% vascular practice. Forty percent felt that 5 years of general surgery with 2 years of vascular surgery should be the training paradigm, while 45% suggested 3 and 3 years, respectively. A majority, 79%, felt that future demand would exceed the available manpower, while 17% suggested that manpower would meet demand. The major challenges to the future of vascular surgery were felt to be competition from cardiology (82%) or radiology (30%) and lack of an independent board (29%). Seventeen percent were not aware of the ABVS, and only 2% were against it; 71% suggested that vascular privileges be restricted to board-certified vascular surgeons. Seventy-six percent were interested in forming an association for vascular trainees to address the issues of the future job market (67%), endovascular training during fellowship (56%), increasing focus on the vascular fellows at national meetings (49%), and representation for the fellows on the national councils (37%). This survey suggests that several significant issues exist in the minds of vascular trainees that have not been addressed and may present opportunities for further dialogue.     

Saccharomyces cerevisiae Msh2-Msh6 DNA binding kinetics reveal a mechanism of targeting sites for DNA mismatch repair

The DNA mismatch repair system (MMR) identifies replication errors and damaged bases in DNA and functions to preserve genomic integrity. MutS performs the task of locating mismatched base pairs, loops and lesions and initiating MMR, and the fundamental question of how this protein targets specific sites in DNA is unresolved. To address this question, we examined the interactions between Saccharomyces cerevisiae Msh2-Msh6, a eukaryotic MutS homolog, and DNA in real time. The reaction kinetics reveal that Msh2-Msh6 binds a variety of sites at similarly fast rates (k_ON ∼ 10⁷ M^-1 s^-1), and its selectivity manifests in differential dissociation rates; e.g., the protein releases a 2-Aminopurine:T base pair approximately 90-fold faster than a G:T mismatch. On releasing the 2-Ap:T site, Msh2-Msh6 is able to move laterally on DNA to locate a nearby G:T site. The long-lived Msh2-Msh6·G:T complex triggers the next step in MMR—formation of an ATP-bound clamp—more effectively than the short-lived Msh2-Msh6·2-Ap:T complex. Mutation of Glu in the conserved Phe-X-Glu DNA binding motif stabilizes Msh2-Msh6_E339A·2-Ap:T complex, and the mutant can signal 2-Ap:T repair as effectively as wild-type Msh2-Msh6 signals G:T repair. These findings suggest a targeting mechanism whereby Msh2-Msh6 scans DNA, interrogating base pairs by transient contacts and pausing at potential target sites, and the longer the pause the greater the likelihood of MMR.     

Identification of malaria hot spots for focused intervention in tribal state of India: a GIS based approach

Background  

In India, presently malaria shows a declining trend whereas Plasmodium falciparum (Pf) cases show an up trend. In central India, specifically, Madhya Pradesh (M.P.) a forested and tribal area, control of malaria is logistically difficult and outbreaks are frequently recorded, reasons for this being inadequate surveillance, poor reporting, a time lag in reporting to decision makers and a lack of geo referenced information to pin point the trouble spots for a timely preventive action.     

Chronic kidney disease after liver,cardiac, lung,heart–lung,and hematopoietic stem cell transplant

Patient survival after cardiac, liver, and hematopoietic stem cell transplant (HSCT) is improving; however, this survival is limited by substantial pretransplant and treatment-related toxicities. A major cause of morbidity and mortality after transplant is chronic kidney disease (CKD). Although the majority of CKD after transplant is attributed to the use of calcineurin inhibitors, various other conditions such as thrombotic microangiopathy, nephrotic syndrome, and focal segmental glomerulosclerosis have been described. Though the immunosuppression used for each of the transplant types, cardiac, liver and HSCT is similar, the risk factors for developing CKD and the CKD severity described in patients after transplant vary. As the indications for transplant and the long-term survival improves for these children, so will the burden of CKD. Nephrologists should be involved early in the pretransplant workup of these patients. Transplant physicians and nephrologists will need to work together to identify those patients at risk of developing CKD early to prevent its development and progression to end-stage renal disease.