Enzymatic degradation of starch thermoplastic blends using samples of different thickness

The material studied was a thermoplastic blend of corn starch with a poly(ethylene-vinyl alcohol) copolymer, SEVA-C. The influence of both the material’s exposed surface and enzyme concentration on degradation kinetics was studied. As α-amylase is present in the blood plasma, experiments were performed, varying the material thickness and the α-amylase between 50 and 100 units/l, at 37°C, lasting up to 90 days. Four different batches using SEVA-C and starch samples of different thickness were performed. The positive correlation between degradation rate and the exposed material surface was confirmed, since thin films with larger exposed surfaces were degraded faster than thick square plates having the same total mass. The degradation extent depends on the total amount of amorphous starch present in the formulation rather than on the amount of enzyme used and the minimum thickness to ensure maximum degradation was estimated to be close to 0.25 mm

The effectiveness of chemotherapy for treatment of high grade astrocytoma in children: Results of a randomized trial

Fifty-eight patients with high-grade astrocytoma were treated by members of the Childrens Cancer Study Group in a prospective randomized trial designed to study the effectiveness of chemotherapy as an adjuvant to standard surgical treatment and radiotherapy. Following surgical therapy, patients were assigned randomly to radiotherapy with or without chemotherapy consisting of chloroethyl-cyclohexyl nitrosourea, vincristine, and prednisone. Treatment with chemotherapy prolonged survival and event-free survival. Five-year event-free survival was 46% for patients in the radiotherapy and chemotherapy group, and 18% for patients in the radiotherapy-alone group. Five-year survival was similarly improved. The differences in outcome due to treatment were statistically significant after correcting for imbalances in important prognostic factors (event-free survival, p = 0.026; survival, p = 0.067). The presence of mitoses or necrosis in the tumor specimen was associated with poorer outcome. Patients whose initial surgery was limited to biopsy, and patients with basal ganglia lesions, also had significantly worse outcome. Chemotherapy administered at the time of recurrence in a small number of patients did not produce any long-term survivors. This study is to our knowledge the only randomized trial to investigate effectiveness of chemotherapy in the treatment of high-grade astrocytoma in children.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/45395/1/11060_2004_Article_BF00165101.pd

Toward osteogenic differentiation of marrow stromal cells and in vitro production of mineralized extracellular matrix onto natural scaffolds

Uncorrected proofTissue engineering has emerged as a new interdisciplinary field for the repair of various tissues, restoring their functions by using scaffolds, cells, and/or bioactive factors. A temporary scaffold acts as an extracellular matrix analog to culture cells and guide the development of new tissue. In this chapter, we discuss the preparation of naturally derived scaffolds of polysaccharide origin, the osteogenic differentiation of mesenchymal stem cells cultured on biomimetic calcium phosphate coatings, and the delivery of biomolecules associated with extracellular matrix mineralization

Accurate imaging meets new treatment modality; MRI guided focal laser ablation for prostate cancer. The first 10 cases in Australia

Introduction & objectives: In the current era of increasing surveillance for low risk prostate cancer (PCa), the concept of partial prostatectomy or prostate lumpectomy is gaining recognition. We present our initial experience of MRI guided focal laser ablation of prostate cancer. The aim of the study was to assess the feasibility and safety to visualise, target and ablate the prostate cancer lesion in real time MRI. Methods: After ethics board approval was obtained, patients with mpMRI and biopsy proven focal prostate cancer lesion, were offered a transperineal MRI guided focal laser thermal ablation. Exclusion criteria were Gleason score > 7, PSA > 10, > cT2b, multiple or high volume lesion. The procedure was performed using a Siemens WideBore T3 MRI. Patients were placed in supine position utilising a transperineal MRI template in the first 7 patients and transrectal in the recent patients via Dynacad target localisation. Following sedation, urinary catheter was inserted. MRI was done for localisation of the template, or transrectal probe followed by Axial T2 high resolution fast spin echo for lesion localisation. An MRI compatible needle was inserted after calculating the trajectory of the laser fiber. The laser fiber replaced the needle trocar and thermal ablation was done under real time MRI thermal mapping, enabling visualisation of lesion the lesion being actively treated. Post ablation contrast MRI was performed to confirm the size and location of the treated area. Results: From February 2014, 10 patients, average age 59 years and PSA 4.5 ng/mL (range 2.4–7.7) were included in our study. Prior to the treatment, 5 patients had Gleason 7, and additional 5 had Gleason 6. All patients were treated as outpatients. Lesions were targeted and treated successfully and confirmed with post treatment contrast MRI. Treatment duration was on average 2 h and 1 h in recovery. One patient had a urinary retention post treatment, he was commenced on alpha-blocker, and catheter removed 5 days later. Two patients complained of perineal discomfort on the day of the procedure. Conclusion: This is the first Phase II trial of Focal treatment of PCa using Laser ablation, as an outpatient procedure in the southern hemisphere. We managed to delivery this treatment with no technical issues and with excellent patient's tolerance. This technique provides a precise targeting and tissue destruction of the lesion only and avoids unnecessary complications of treating the entire prostate. More studies should be done, with larger number of patients and long-term follow-up, to confirm the disease and biochemical free survival benefit of this technique.1 page(s

The effect of hypocapnia on the autoregulation of cerebral blood flow during administration of isoflurane

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The stability of polysiloxanes incorporating nano-scale physical property modifiers

Reported here is the synthesis and subsequent characterization of the physical and chemical properties of novel polysiloxane elastomers modified with a series of polyhedraloligomericsilsequioxane (POSS) molecular silicas. The physical properties of the formulated nanocomposite systems have been characterized with a combination of dynamic mechanical analysis (DMA), broadband dielectric spectroscopy (BDS) and confocal Raman microscopy. The results of the physical property characterization demonstrate that the incorporation of low levels (1-4% by wt.) of POSS particles into the polysiloxane network leads to significant improvements in the mechanical properties of the elastomer and significantly alters the motional chain dynamics of the system as a whole. The results of studies performed to assess the long-term stability of these novel nanocomposite systems have demonstrated that POSS physical property modifiers can significantly alter the thermal stability of polysiloxane elastomers. Physically dispersed POSS has also been shown in some cases to be both mobile and disruptive within the polysiloxane networks, agglomerating into domains on a micron scale and migrating to the surface of the elastomers. This work demonstrates both the potential of POSS nanoparticles as physical property modifiers and describes the effects of POSS on the physical and chemical stability of polysiloxane systems

The Use of Botulinum toxin A elongates the lateral abdominal wall prior to surgery for giant complex ventral hernias and may replace component separation

Introduction: Complex ventral hernias occur in up to 15% of patients undergoing abdominal surgery. Surgical repair of recurrent abdominal incisional hernia(s) can be challenging due to complex operative conditions, intense post-operative pain, potential respiratory compromise and lateral muscle traction predisposing to early recurrence. Reported recurrence rates, within 36 months vary between 15-21% for open repair and 7-15.5% for laparoscopic repair and as high as 56%, 47% and 48% after first, second and third hernia repairs. Despite innovation in surgical techniques, such as the introduction of surgical mesh and component separation, there have been minimal improvements in post-operative morbidity and hernia recurrence. Botulinum toxin type A (BTA), a neuromodulating agent, increasingly used for various clinical applications including dystonia, spasticity, cerebral palsy, hyperhidrosis, hypersalivation, bladder dysfunction, skin wrinkles and pain management over the last 40 years. There are now a few case reports, in humans and animals, using BTA for the peri-operative management in abdominal wall surgery with the aims of: I) improving analgesia, 2) using the flaccid paralysis to lengthen abdominal oblique muscles and facilitate apposition of the edges of the defect akin to the effect of component separation but without disrupting the fascial integrity and 3) decreasing lateral traction and thus reducing tension before and after surgical repair. Methods: A prospective pilot study measured the effect of preoperative BTA prior to elective repair of complex recurrent ventral hernias. Each patient received 300 untis of BTA injected in equal divided doses into the external oblique, internal oblique and transversus abdominis muscles at three sites on each side of the lateral abdominal wall (each dose 50 units). The six injections were performed in an outpatient setting under ultrasound control two weeks prior to surgery. Pre and post-BTA abdominal computed tomography (CT) measured changes in abdominal wall muscle thickness and length of the hernia defects. All hernias were subsequently repaired with laparoscopic (IPOM) or laparoscopic assisted mesh techniques in a one- or two-staged procedure with Sepramesh™ (Bard, Cranston RI, USA). Results: We report our initial 12 patients (lOM:2F), who underwent preoperative BTA prior to laparoscopic hernia repair between November 2012 and October 2014. The mean age was 59 years (range 32-83yrs) with mean defect size of 14.4 cm (range 7-28 cm, maximal linear defect). BTA injections were tolerated by all patients with no complications and they resumed normal activities between the injections and surgery. Comparison between pre and post-BTA injection abdominal CT scans demonstrated a mean unstretched lengthening of lateral abdominal muscle of 2.9 cm/side (range 0.7-5.9cm), thinning of7.3 mm (range 0.4-14.3mm). CT imaging also demonstrated reduction in loss of domain and reduction of abdominal hernia contents into the abdominal cavity in 12 patients prior to surgery. All the hernias were successfully reduced using standard laparoscopic or laparoscopic assisted techniques with surprising ease at the time of surgery without any fascial separation. There have been no post-operative recurrences, to date. The only side effect of BTA injections was the feeling of "bloatedness', day 4-day 5 post-injection, and increase abdominal girth, as reported by patient. Conclusion: Pre-operative BTA injection prior to complex abdominal hernia repair was a safe procedure that resulted in flaccid paralysis, unstretched elongation and thinning of the lateral abdominal muscles and decrease in loss of domain and hernia defect prior to surgery. We hypothesise that the flaccid paralysis of the lateral abdominal wall, due to pre-operative BTA, decreases lateral traction to enable: I) reduction of hernia defect at time of surgery, 2) decreases tension through the repair, for the first 2 months or more, during the critical healing phase and 3) may reduce the need for component separation.2 page(s