Archive for February, 2010

Solitary metastatic adenocarcinoma of the sternum treated by total sternectomy and chest wall reconstruction using a Gore-Tex patch and myocutaneous flap: a case report

Sunday, February 28th, 2010

IntroductionThe consequences of bone metastasis are often devastating. The exact incidence of bone metastasis is unknown, but it is estimated that 350,000 people die with bone metastasis annually in the United States. The incidence of local recurrences after mastectomy and breast-conserving therapy varies between 5% and 40% depending on risk factors and primary therapy. So far a standard therapy of local recurrences has not been defined and the indications extend of resection and reconstruction considerations have been infrequently described. The present case report reviews the use of sternectomy for breast cancer recurrence, highlights the need for thorough clinical and radiologic evaluation to ensure the absence of other systemic disease and furthermore suggests the use of serratus anterior muscle flap as a pedicle graft to cover full-thickness defects of the anterior chest wall.Case presentationWe report a case of a 70-year old Caucasian female who was referred to our hospital for management of a retrosternal mediastinal mass. She had undergone radical mastectomy in 1999. CT and MRI revealed a 74.23 x 37.7 x 133.6mm mass in the anterior mediastinum, adjacent to the main pulmonary artery, the right ventricle and ascending aorta. We performed total sternectomy at all layers encompassing the skin, subcutaneous tissues, right pectoralis major muscle, all the costal cartilages, and the anterior part of pericardium. Immediate closure of the defect was performed with a single 0.6 mm Gore-Tex Cardiovascular patch combined with a serratus anterior muscle flap. At 18 month follow up the patient remains asymptomatic.
Conclusion:
Chest wall resection has become a critical component of the thoracic surgeon’s armamentarium. It may be performed to treat either benign conditions (osteoradionecrosis, osteomyelitis) or malignant disease. There are, however, very few reports on results of full-thickness complete chest wall resections for locally recurrent breast cancer with sufficient safety margins and even fewer with operative technique description of the use of serratus anterior muscle as a pedicled flap.

The Boston Puerto Rican Health Study, a longitudinal cohort study on health disparities in Puerto Rican adults: challenges and opportunities.

Sunday, February 28th, 2010

Background:
The Boston Puerto Rican Health Study is an ongoing longitudinal cohort study designed to examine the role of psychosocial stress on presence and development of allostatic load and health outcomes in Puerto Ricans, and potential modification by nutritional status, genetic variation, and social support.
Methods:
Self-identified Puerto Ricans, aged 45-75 years and residing in the Boston, MA metro area, were recruited through door-to-door enumeration and community approaches. Participants completed a comprehensive set of questionnaires and tests. Blood, urine and salivary samples were extracted for biomarker and genetic analysis. Measurements are repeated at a two-year follow-up.
Results:
A total of 1500 eligible participants completed baseline measurements, with nearly 80% two-year follow-up retention. The majority of the cohort is female (70%), and many have less than 8th grade education (48%), and fall below the poverty level (59%). Baseline prevalence of health conditions is high for this age range: considerable physical (26%) and cognitive (7%) impairment, obesity (57%), type 2 diabetes (40%), hypertension (69%), arthritis (50%) and depressive symptomatology (60%).
Conclusions:
The enrollment of minority groups presents unique challenges. This report highlights approaches to working with difficult to reach populations, and describe some of the health issues and needs of Puerto Rican older adults. These results may inform future studies and interventions aiming to improve the health of this and similar communities.

Tai Chi for osteopenic women: design and rationale of a pragmatic randomized controlled trial

Sunday, February 28th, 2010

Background:
Post-menopausal osteopenic women are at increased risk for skeletal fractures. Current osteopenia treatment guidelines include exercise, however, optimal exercise regimens for attenuating bone mineral density (BMD) loss, or for addressing other fracture-related risk factors (e.g. poor balance, decreased muscle strength) are not well-defined. Tai Chi is an increasingly popular weight bearing mind-body exercise that has been reported to positively impact BMD dynamics and improve postural control, however, current evidence is inconclusive. This study will determine the effectiveness of Tai Chi in reducing rates of bone turnover in post-menopausal osteopenic women, compared with standard care, and will preliminarily explore biomechanical processes that might inform how Tai Chi impacts BMD and associated fracture risks.
Methods:
A total of 86 post-menopausal women, aged 45-70y, T-score of the hip and/or spine -1.0 and -2.5, have been recruited from primary care clinics of a large healthcare system based in Boston. They have been randomized to a group-based 9-month Tai Chi program plus standard care or to standard care only. A unique aspect of this trial is its pragmatic design, which allows participants randomized to Tai Chi to choose from a pre-screened list of community-based Tai Chi programs. Interviewers masked to participants’ treatment group assess outcomes at baseline and 3 and 9 months after randomization. Primary outcomes are serum markers of bone resorption (C-terminal cross linking telopeptide of type I collagen, bone formation (osteocalcin), and BMD of the lumbar spine and proximal femur (dual-energy X-ray absorptiometry). Secondary outcomes include health-related quality-of-life, exercise behavior, and psychological well-being. In addition, kinetic and kinematic characterization of gait, standing, and rising from a chair are assessed in subset of participants (n=16) to explore the feasibility of modeling skeletal mechanical loads and postural control as mediators of fracture risk.
Conclusion:
Results of this study will provide preliminary evidence regarding the value of Tai Chi as an intervention for decreasing fracture risk in osteopenic women. They will also inform the feasibility, value and potential limitations related to the use of pragmatic designs for the study of Tai Chi and related mind-body exercise. If the results are positive, this will help focus future, more in-depth, research on the most promising potential mechanisms of action identified by this study.Trial registration: This trial is registered in Clinical Trials.gov, with the ID number ofNCT01039012.

Dual effect of Plasmodium-infected erythrocytes on dendritic cell maturation

Sunday, February 28th, 2010

Background:
Infection with Plasmodium is the cause of malaria, a disease characterized by a high inflammatory response in the blood. Dendritic cells (DC) participate in both adaptive and innate immune responses, influencing the generation of inflammatory responses. DC can be activated through different receptors, which recognize specific molecules in microbes and induce the maturation of DC.
Methods:
Using Plasmodium yoelii, a rodent malaria model, the effect of Plasmodium-infected erythrocytes on DC maturation and TLR responses have been analysed.
Results:
It was found that intact erythrocytes infected with P. yoelii do not induce maturation of DC unless they are lysed, suggesting that accessibility of parasite inflammatory molecules to their receptors is a key issue in the activation of DC by P. yoelii. This activation is independent of MyD88. It was also observed that pre-incubation of DC with intact P. yoelii-infected erythrocytes inhibits the maturation response of DC to other TLR stimuli. The inhibition of maturation of DC is reversible, parasite-specific and increases with the stage of parasite development, with complete inhibition induced by schizonts (mature infected erythrocytes). Plasmodium yoelii-infected erythrocytes induce a broad inhibitory effect rendering DC non-responsive to ligands for TLR2, TLR3, TLR4, TLR5, TLR7 and TLR9.
Conclusions:
Despite the presence of inflammatory molecules within Plasmodium-infected erythrocytes, which are probably responsible for DC maturation induced by lysates, intact Plasmodium-infected erythrocytes induce a general inhibition of TLR responsiveness in DC. The observed effect on DC could play an important role in the pathology and suboptimal immune response observed during the disease. These results help to explain why immune functions are altered during malaria, and provide a system for the identification of a parasite-derived broad inhibitor of TLR-mediated signaling pathways.

Attracting, trapping and killing disease-transmitting mosquitoes using odor-baited stations -The Ifakara Odor-Baited Stations

Sunday, February 28th, 2010

Background:
To accelerate efforts towards control and possibly elimination of mosquito-borne diseases such as malaria and lymphatic filariasis, optimally located outdoor interventions could be used to complement existing intradomicilliary vector control methods such as house spraying with insecticides and insecticidal bednets.
Methods:
We describe a new odor-baited station for trapping, contaminating and killing disease-transmitting mosquitoes. This device, named the ‘Ifakara Odor-baited Station’ (Ifakara OBS), is a 4m3 hut-shaped canvas box with seven openings, two of which may be fitted with interception traps to catch exiting mosquitoes. It is baited with synthetic human odors and may be augmented with contaminants including toxic insecticides or biological agents.
Results:
In field trials where panels of fabric were soaked in 1% pirimiphos-methyl solution and suspended inside the Ifakara OBS, at least 73.6% of Anopheles arabiensis, 78.7% of Culex and 60% of Mansonia mosquitoes sampled while exiting the OBS, died within 24 hours. When used simply as a trap and evaluated against two existing outdoor traps, Ifakara Tent trap and Mosquito Magnet-X(R), the OBS proved more efficacious than the Ifakara Tent trap in catching all mosquito species found (P<0.001). Compared to the Mosquito Magnet-X(R), it was equally efficacious in catching An. arabiensis (P=0.969), but was less efficacious against Culex (P<0.001) or Mansonia species (P<0.001).
Conclusion:
The Ifakara OBS is efficacious against disease-carrying mosquitoes including the malaria vector, An. arabiensis and Culicine vectors of filarial worms and arboviruses. It can be used simultaneously as a trap and as a contamination or killing station, meaning most mosquitoes which escape trapping would leave when already contaminated and die shortly afterwards. This technique has potential to complement current vector control methods, by targeting mosquitoes in places other than human dwellings, but its effectiveness in the field will require cheap, long-lasting and easy-to-use mosquito lures.