A nonlinear competitive model of the prostate tumor growth under intermittent androgen suppression.

Hormone suppression has been the primary modality of treatment for prostate cancer. However long-term androgen deprivation may induce androgen-independent (AI) recurrence. Intermittent androgen suppression (IAS) is a potential way to delay or avoid the AI relapse. Mathematical models of tumor growth and treatment are simple while they are capable of capturing the essence of complicated interactions. Game theory models have analyzed that tumor cells can enhance their fitness by adopting genetically determined survival strategies. In this paper, we consider the survival strategies as the competitive advantage of tumor cells and propose a new model to mimic the prostate tumor growth in IAS therapy. Then we investigate the competition effect in tumor development by numerical simulations. The results indicate that successfully IAS-controlled states can be achieved even though the net growth rate of AI cells is positive for any androgen level. There is crucial difference between the previous models and the new one in the phase diagram of successful and unsuccessful tumor control by IAS administration, which means that the suggestions from the models for medication can be different. Furthermore we introduce quadratic logistic terms to the competition model to simulate the tumor growth in the environment with a finite carrying capacity considering the nutrients or inhibitors. The simulations show that the tumor growth can reach an equilibrium state or an oscillatory state with the net growth rate of AI cells being androgen independent. Our results suggest that the competition and the restraint of a limited environment can enhance the possibility of relapse prevention.

A two-year follow-up study of cotransplantation with neural stem/progenitor cells and mesenchymal stromal cells in ischemic stroke patients.

Stem cell therapy is an emerging therapeutic modality in the treatment of stroke. We assessed the safety and feasibility of the cotransplantation of neural stem/progenitor cells (NSPCs) and mesenchymal stromal cells (MSCs) in patients with ischemic stroke. Eight patients were enrolled in this study. All patients had a hemisphere with infarct lesions located on one side of the territories of the cerebral middle or anterior arteries as revealed with cranial magnetic resonance imaging (MRI). The patients received one of the following two types of treatment: the first treatment involved four intravenous injections of MSCs at 0.5 × 10(6)/kg body weight; the second treatment involved one intravenous injection of MSCs at 0.5 × 10(6)/kg weight followed by three injections of MSCs at 5 × 10(6)/patient and NSPCs at 6 × 10(6)/patient through the cerebellomedullary cistern. The patients' clinical statuses were evaluated with the National Institutes of Health Stroke Scale (NIHSS), the modified Rankin Scale (mRS), and the Barthel index (BI). Six patients were given four cell transplantations. The most common side effect of stem cell transplantation in these six cases was low fever that usually lasted 2-4 days after each therapy. One patient exhibited minor dizziness. All side effects appeared within the first 2-24 h of cell transplantation, and they resolved without special treatment. There was no evidence of neurological deterioration or neurological infection. Most importantly, no tumorigenesis was found at a 2-year follow-up. The neurological functions, disability levels, and daily living abilities of the patients in this study were improved. While these observations support the use of the combination transplantation of NSPCs and MSCs as a safe and feasible method of improving neurological function, further studies that include larger samples, longer follow-ups, and control groups are still needed. This manuscript is published as part of the International Association of Neurorestoratology (IANR) special issue of Cell Transplantation.

Method for reduction of background artifacts of images in scanning holography with a Fresnel-zone-plate coded aperture.

Near-infrared scanning holography with a Fresnel zone plate (FZP) coded aperture has potential applications in imaging through turbid media. However, the nonnegative intensity-distribution function of the FZP coded aperture introduces the background artifacts into the reconstructed images, reducing the contrast and the signal-to-noise ratio (SNR) of the images. A novel method termed as the composite hologram is proposed to reduce the artifacts. The computer simulations showed that the contrast and the SNR of the reconstructed images had improvements of at least 50.2% and 5.58-dB, respectively, compared with the conventional method. The composite hologram of a metal ring with a 6.0-mm diameter made by a wire with a 0.4-mm diameter immersing in 1% intralipid solution was recorded, and the reconstruction was performed numerically. The experimental results demonstrated that the contrast and the SNR of the reconstructed image had improvements of at least 32.3% and 2.51-dB, respectively.