Microwave focal therapy of prostate cancer: a non-clinical study and exploratory clinical trial.

OBJECTIVE: To examine the safety and efficacy of microwave tissue coagulation (MTC) for prostate cancer and assess its use in lesion-targeted focal therapy in a non-clinical study and a clinical phase II trial. METHODS: In the non-clinical study using Microtaze® -AFM-712 (Alfresa Pharma Corporation, Osaka, Japan) with an MTC needle, MTC was performed using a transperineal approach to targeted canine prostatic tissue under real-time ultrasonography guidance. Using various MTC output and irradiation time combinations, the targeted and surrounding tissues (rectum, bladder and fat) were examined to confirm the extent of coagulative necrosis or potential cell death, and to compare intra-operative ultrasonography and pathology findings. The exploratory clinical trial was conducted to examine the safety and efficacy of MTC. Five selected patients underwent transperineal MTC to clinically single lesion magnetic resonance imaging (MRI)-visible lesions with Gleason score 3 + 4 or 4 + 4. Prostate-specific antigen (PSA), MRI and Expanded Prostate Cancer Index Composite questionnaire findings were compared before and 6 months after surgery. RESULTS: The region of coagulative necrosis was predictable by monitoring of ultrasonically visible vaporization; thus, by placing the MTC needle at a certain distance, we were able to perform a safe procedure without adverse events affecting the surrounding organs. Based on the non-clinical study, which used various combinations of output and irradiation time, MTC with 30-W output for 60-s irradiation was selected for the prostate. Based on the predictable necrosis, the therapeutic plan (where to place the MTC needle to achieve complete ablation of the target and how many sessions) was strictly determined per patient. There were no serious adverse events in any patient and only temporary urinary symptoms related to MTC therapy were observed. Furthermore, post-treatment satisfaction was very high. All preoperative MRI-visible lesions disappeared, and PSA decreased by 55% 6 months after surgery. CONCLUSION: Microwave tissue coagulation may be an option for lesion-targeted focal therapy for prostate cancer.

Development of the prethalamus is crucial for thalamocortical projection formation and is regulated by Olig2.

Thalamocortical axons (TCAs) pass through the prethalamus in the first step of their neural circuit formation. Although it has been supposed that the prethalamus is an intermediate target for thalamocortical projection formation, much less is known about the molecular mechanisms of this targeting. Here, we demonstrated the functional implications of the prethalamus in the formation of this neural circuit. We show that Olig2 transcription factor, which is expressed in the ventricular zone (VZ) of prosomere 3, regulates prethalamus formation, and loss of Olig2 results in reduced prethalamus size in early development, which is accompanied by expansion of the thalamic eminence (TE). Extension of TCAs is disorganized in the Olig2-KO dorsal thalamus, and initial elongation of TCAs is retarded in the Olig2-KO forebrain. Microarray analysis demonstrated upregulation of several axon guidance molecules, including Epha3 and Epha5, in the Olig2-KO basal forebrain. In situ hybridization showed that the prethalamus in the wild type excluded the expression of Epha3 and Epha5, whereas loss of Olig2 resulted in reduction of this Ephas-negative area and the corresponding expansion of the Ephas-positive TE. Dissociated cultures of thalamic progenitor cells demonstrated that substrate-bound EphA3 suppresses neurite extension from dorsal thalamic neurons. These results indicate that Olig2 is involved in correct formation of the prethalamus, which leads to exclusion of the EphA3-expressing region and is crucial for proper TCA formation. Our observation is the first report showing the molecular mechanisms underlying how the prethalamus acts on initial thalamocortical projection formation.

Expression of myelin genes in the developing chick retina.

In submammalian animals including chicks, the retina contains oligodendrocytes (OLs), and axons in the optic fiber layer are wrapped with compact myelin within the retina; however, the expression of myelin genes in the chick retina has not been demonstrated yet. In the present study, we examined the expression of three myelin genes (proteolipid protein, PLP; myelin basic protein, MBP; cyclic nucleotide phosphodiesterase, CNP) and PLP in the developing chick retina, in comparison to the localization of Mueller cells. In situ hybridization demonstrated that all three myelin genes began to be expressed at E14 in the chick embryo retina. They are mostly restricted to the ganglion cell layer and the optic fiber layer, with a few exceptions in the inner nuclear layer where Mueller cells reside; however, PLP mRNA+ cells do not express glutamine synthetase, or vice versa. The present results elucidate that myelin genes are expressed only by OLs that are mostly localized in the innermost layer of the developing chick retina.