Potential Therapeutic Approach using Aromatic l-amino Acid Decarboxylase and Glial-derived Neurotrophic Factor Therapy Targeting Putamen in Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative illness characterized by specific loss of dopaminergic neurons, resulting in impaired motor movement. Its prevalence is twice as compared to the previous 25 years and affects more than 10 million individuals. Lack of treatment still uses levodopa and other options as disease management measures. Treatment shifts to gene therapy (GT), which utilizes direct delivery of specific genes at the targeted area. Therefore, the use of aromatic L-amino acid decarboxylase (AADC) and glial-derived neurotrophic factor (GDNF) therapy achieves an effective control to treat PD. Patients diagnosed with PD may experience improved therapeutic outcomes by reducing the frequency of drug administration while utilizing provasin and AADC as dopaminergic protective therapy. Enhancing the enzymatic activity of tyrosine hydroxylase (TH), glucocorticoid hormone (GCH), and AADC in the striatum would be useful for external L-DOPA to restore the dopamine (DA) level. Increased expression of glutamic acid decarboxylase (GAD) in the subthalamic nucleus (STN) may also be beneficial in PD. Targeting GDNF therapy specifically to the putaminal region is clinically sound and beneficial in protecting the dopaminergic neurons. Furthermore, preclinical and clinical studies supported the role of GDNF in exhibiting its neuroprotective effect in neurological disorders. Another Ret receptor, which belongs to the tyrosine kinase family, is expressed in dopaminergic neurons and sounds to play a vital role in inhibiting the advancement of PD. GDNF binding on those receptors results in the formation of a receptor-ligand complex. On the other hand, venous delivery of recombinant GDNF by liposome-based and encapsulated cellular approaches enables the secure and effective distribution of neurotrophic factors into the putamen and parenchyma. The current review emphasized the rate of GT target GDNF and AADC therapy, along with the corresponding empirical evidence.

Tremor and Rigidity in Patients with Parkinson's Disease: Emphasis on Epidemiology, Pathophysiology and Contributing Factors.

Parkinson's disease (PD) is the second most prominent neurodegenerative movement disorder after Alzheimer's disease, involving 2-3% of the population aged above 65 years. This is mainly triggered by the depletion of dopaminergic neurons located in substantia nigra pars compacta (SNpc) in the region of basal ganglia. At present, diagnosis for symptoms of PD is clinical, contextual, unspecified and therapeutically incomprehensive. Analysis of various causes of PD is essential for an accurate examination of the disease. Among the different causes, such as tremors and rigidity, unresponsiveness to the current treatment approach contributes to mortality. In the present review article, we describe various key factors of pathogenesis and physiology associated with tremors and rigidity necessary for the treatment of PI (postural instability) in patients with PD. Additionally, several reports showing early tremor and rigidity causes, particularly age, cortex lesions, basal ganglia lesions, genetic abnormalities, weakened reflexes, nutrition, fear of fall, and altered biomechanics, have been explored. By summarizing the factors that contribute to the disease, histopathological studies can assess rigidity and tremor in PD. With a clear understanding of the contributing factors, various prospective studies can be done to assess the incidence of rigidity and tremors.

Neoadjuvant docetaxel/estramustine prior to radical prostatectomy or external beam radiotherapy in high risk localized prostate cancer: a phase II trial.

BACKGROUND: Patients with locally advanced or organ confined, high risk, prostate cancer are at significant risk of having disease recurrence despite definitive local therapy. We evaluated the 2-year progression-free survival of subjects treated with chemotherapy administered prior to definitive therapy with surgery or radiation. PATIENTS AND METHODS: Patients (n = 24) with locally advanced and high risk localized prostate cancer were treated with neoadjuvant docetaxel 36 mg/m2 i.v. weekly for 3 weeks and estramustine 140 mg orally 3 times daily for 3 consecutive days every 28 days prior to definitive treatment with prostatectomy or radiation. RESULTS: All evaluable patients, except 1, completed the proposed cycles of neoadjuvant chemotherapy with minimal dose reductions or delays. Of the 22 evaluable patients, 12 underwent radical prostatectomy and 10 underwent external beam radiation therapy. Twenty-one of 22 patients achieved a prostate-specific antigen (PSA) reduction > 25%. There were no pathologic complete responses. With a median follow-up of 24 months, the 2-year progression-free survival was 45%. CONCLUSIONS: Our findings support the safety, tolerability, and efficacy of neoadjuvant chemotherapy in patients with men with high risk, locally advanced prostate adenocarcinoma, although the relative contributions of androgen deprivation therapy and docetaxel cannot be determined. The effectiveness of neoadjuvant chemotherapy in preventing prostate cancer relapses should be studied in a randomized trial.

In vivo intraoperative radiotherapy: a novel approach to radiotherapy for early stage breast cancer.

INTRODUCTION: Intraoperative radiotherapy (IORT) has the potential to eliminate the access problems associated with standard 6-week post-operative external beam radiotherapy for patients with breast cancer. However, accurate delivery of the IORT dose for breast cancer has been problematic due to difficulty estimating the tumor bed after tumor removal and tissue re-approximation. We are investigating the feasibility of partial breast irradiation using a single fraction of IORT delivered to the tumor in vivo prior to surgical resection. METHODS: In a trial, approved by the University of North Carolina School of Medicine Institutional Review Board, patients > or =55 years old with infiltrating ductal carcinoma without an extensive intraductal component with an overall tumor size < or =3.0 cm receive a single dose of IORT in place of standard post-operative radiotherapy. RESULTS: All patients undergo preoperative ultrasonography to define the target volume. In a standard operating room, the tumor is exposed through a standard partial mastectomy incision. IORT is then delivered using a mobile, self-shielded, magnetron-driven X-band linear accelerator (Intraop Corp, Santa Clara, CA, USA). 15 Gy is delivered to the 90% isodose line covering the tumor with a 1 cm margin anterior-posterior and 2 cm margins laterally. After IORT, partial mastectomy is performed in the usual manner. CONCLUSIONS: IORT for breast cancer, delivered to the exposed tumor in vivo, is feasible and allows accurate estimation of the tumor bed. Further follow-up is ongoing to determine the efficacy of this approach.

Feasibility of breast preserving therapy with single fraction in situ radiotherapy delivered intraoperatively.

BACKGROUND: Accelerated partial breast irradiation (APBI) has gained widespread interest as a means of improving the convenience and availability of breast conserving radiotherapy. Intraoperative radiation therapy (IORT) is an APBI technique that delivers breast radiotherapy as a single dose at the time of partial mastectomy. We adapted the technique of Veronesi to deliver IORT prior to tumor excision to improve delivery to the region at risk and reduce the volume of normal tissue irradiated. METHODS: Patients age >or=55 with ultrasonographically defined tumors

Complications associated with neoadjuvant radiotherapy in the multidisciplinary treatment of retroperitoneal sarcomas.

INTRODUCTION: Retroperitoneal sarcomas (RPS) remain a therapeutic challenge due to high local recurrence rates. Preoperative RT offers theoretical advantages in the multidisciplinary care of RPS. The purpose of our study was to evaluate our experience using preoperative radiotherapy (PRT) in the treatment of RPS. METHODS: This is a single-institution review of patients with RPS treated with PRT from 1994 until 2004. Three radiation oncologists and four surgical oncologists were involved. Medical records, tumor registries, and death records were reviewed. RESULTS: Fourteen patients were included; nine were treated for primary presentation and five for recurrent disease. Histologic grade was grade I (n = 3), grade II (n = 3), and grade III (n = 8). Five patients received additional IORT. Radiotherapy complications were generally mild, including nausea (n = 3), diarrhea (n = 1), dehydration (n = 1), anemia (n = 1), and skin changes (n = 1); one required early cessation due to nausea. Thirteen patients had gross negative margins; while 7/13 had negative microscopic margins. Operative complications included anastomotic bleeding (n = 1), fluid collections (n = 2), ileus (n = 3), ascites (n = 2), temporary leg weakness (n = 1), and uncomplicated wound infections (n = 2). In patients with R0 or R1 resections, one and two year local control rates were 64 and 50%. Overall survival for all patients was 90% at 1 year and 74% at 2 years with median survival of 21 months. CONCLUSION: PRT and IORT can be administered effectively in carefully selected patients with resectable RPS. Larger multi-center studies are needed to delineate the role of PRT and IORT to improve local recurrence and survival rates in the treatment of RPS.

Large deformation three-dimensional image registration in image-guided radiation therapy.

In this paper, we present and validate a framework, based on deformable image registration, for automatic processing of serial three-dimensional CT images used in image-guided radiation therapy. A major assumption in deformable image registration has been that, if two images are being registered, every point of one image corresponds appropriately to some point in the other. For intra-treatment images of the prostate, however, this assumption is violated by the variable presence of bowel gas. The framework presented here explicitly extends previous deformable image registration algorithms to accommodate such regions in the image for which no correspondence exists. We show how to use our registration technique as a tool for organ segmentation, and present a statistical analysis of this segmentation method, validating it by comparison with multiple human raters. We also show how the deformable registration technique can be used to determine the dosimetric effect of a given plan in the presence of non-rigid tissue motion. In addition to dose accumulation, we describe a method for estimating the biological effects of tissue motion using a linear-quadratic model. This work is described in the context of a prostate treatment protocol, but it is of general applicability.

Propylthiouracil-induced chemical hypothyroidism with high-dose tamoxifen prolongs survival in recurrent high grade glioma: a phase I/II study.

BACKGROUND: High-dose tamoxifen has had disappointing results as a palliative therapy in recurrent glioma. Insulin-like growth factor 1 (IGF-1) is a thyroid hormone modulated naturally occurring antagonist of tamoxifen-induced cytotoxicity. Thyroid function was suppressed to reduce IGF-1 levels in glioma patients and high-dose tamoxifen administered. MATERIALS AND METHODS: Propylthiouracil was used to induce chemical hypothyroidism in 22 patients with recurrent glioma. Tamoxifen was started within one month and given in escalating doses from 40 mg twice a day up to 80 mg 3 times a day. No significant toxicity developed. RESULTS: Eleven out of 22 patients became hypothyroid. No patients experienced symptoms of clinical hypothyroidism. Median survival was significantly longer in the hypothyroid group (10.1 months versus 3.1 months); p = 0.03. There was a significant decrease in blood levels of IGF-1 (p = 0.02). in hypothyroid patients. CONCLUSION: Patients treated for recurrent high-grade gliomas with high-dose tamoxifen had significantly longer survival when chemical hypothyroidism was induced with propylthiouracil.