Effectiveness and safety of MR-guided focused ultrasound thalamotomy in patients with essential tremor and low skull density ratio: a study of 101 cases.

OBJECTIVE: The objective was to investigate the effectiveness and safety of MR-guided focused ultrasound (MRgFUS) treatment in patients with essential tremor, particularly those with low skull density ratio (SDR) and including those with very low SDR, and to identify the factors influencing treatment effectiveness and to provide insights into therapeutic approaches for patients with lower SDR. METHODS: Real-world data from 101 patients who underwent MRgFUS between July 2019 and March 2022 at a single institution were analyzed. Tremor severity was assessed using the Fahn-Tolosa-Marin Clinical Rating Scale for Tremor (CRST). The patients were categorized into quartile groups based on their mean SDR, and the characteristics, treatment effectiveness, treatment parameters, and adverse events were evaluated among these subgroups. RESULTS: Patients were classified into 4 quartiles based on the mean SDR: quartile 1 (Q1) (SDR 0.26-0.37), Q2 (SDR 0.38-0.42), Q3 (SDR 0.43-0.49), and Q4 (SDR 0.50-0.75). MRgFUS significantly improved total CRST and tremor score across all SDR subgroups. Additionally, there were no significant differences in the improvement rates among the 4 subgroups. Analysis of the treatment parameters revealed that lower mean SDR was associated with lower target maximum temperature and smaller coagulation volume after focused ultrasound (FUS). Regarding adverse events, headache and nausea during FUS and facial and head edema on the day after surgery were more frequent in the Q1 subgroup (very low-SDR group). In contrast, numbness was more common in the Q4 subgroup. However, all these adverse events had resolved by the 3-month follow-up except numbness. CONCLUSIONS: This study suggested that MRgFUS is effective and safe for patients with medication-resistant essential tremor, including those with very low mean SDR. However, the very low-SDR group had insufficient temperature elevation at the target site compared with the high-SDR group, suggesting the need for a different strategy. Notably, with careful adjustments and considerations, positive outcomes can still be achieved in patients with very low SDR. Therefore, very low SDR should not be considered an absolute exclusion criterion because it is expected to increase the number of patients who benefit from MRgFUS.

Improvement in Intraoperative Image Quality in Transcranial Magnetic Resonance-Guided Focused Ultrasound Surgery Using Transmitter Gain Adjustment.

INTRODUCTION: Transcranial magnetic resonance-guided focused ultrasound surgery (TcMRgFUS) has the advantage of allowing immediate evaluation of therapeutic effects after each sonication and intraoperative magnetic resonance imaging (MRI) to visualize the lesion. When the image shows that the lesion has missed the planned target and the therapeutic effects are insufficient, the target of the subsequent ablation can be finely adjusted based on the image. The precision of this adjustment is determined by the image quality. However, the current intraoperative image quality with a 3.0T MRI system is insufficient for precisely detecting the lesion. Thus, we developed and validated a method for improving intraoperative image quality. METHODS: Because intraoperative image quality is affected by transmitter gain (TG), we acquired T2-weighted images (T2WIs) with two types of TG: the automatically adjusted TG (auto TG) and the manually adjusted TG (manual TG). To evaluate the character of images with 2 TGs, the actual flip angle (FA), the image uniformity, and the signal-to-noise ratio (SNR) were measured using a phantom. Then, to assess the quality of intraoperative images, T2WIs with both TGs were acquired during TcMRgFUS for 5 patients. The contrast-to-noise ratio (CNR) of the lesion was retrospectively estimated. RESULTS: The images of the phantom with the auto TG showed substantial variations between the preset and actual FAs (p < 0.01), whereas on the images with the manual TG, there were no variations between the two FAs (p > 0.05). The total image uniformity was considerably lower with the manual TG than with the auto TG (p < 0.01), indicating that the image's signal values with the manual TG were more uniform. The manual TG produced significantly higher SNRs than the auto TG (p < 0.01). In the clinical study, the lesions were clearly detected in intraoperative images with the manual TG, but they were difficult to identify in images with the auto TG. The CNR of lesions in images with manual TG was considerably higher than in images with auto TG (p < 0.01). CONCLUSION: Regarding intraoperative T2WIs using a 3.0T MRI system during TcMRgFUS, the manual TG method improved image quality and delineated the ablative lesion more clearly than the current method with auto TG.

[A Case Report of the Ascending Colon Cancer with Bullous Pemphigoid].

The patient was a 70-year-old man. The patient had progressive anemia while taking 10 mg/day of prednisolone and 100 mg/day of mizoribine orally for bullous pemphigoid, a colonoscopy diagnosed ascending colon cancer. Adenocarcinoma, Group 5 was detected on biopsy. Abdominal computed tomography showed no metastases. The tumor was diagnosed as ascending colon cancer, cT4aN0M0, cStage Ⅱb. We performed laparoscopic right hemicolectomy and D3 dissection. Histopathological examination revealed pT3N0M0, pStage Ⅱa. In the present report, we describe a case of the ascending colon cancer with bullous pemphigoid, and discuss the case with a review of the literature.

Sense transgene-induced post-transcriptional gene silencing in tobacco compromises the splicing of endogenous counterpart genes.

Sense transgene-induced post-transcriptional gene silencing (S-PTGS) is thought to be a type of RNA silencing in which ARGONAUTE1 directs the small interfering RNA (siRNA)-mediated cleavage of a target mRNA in the cytoplasm. Here, we report that the altered splicing of endogenous counterpart genes is a main cause for the reduction of their mature mRNA levels. After the S-PTGS of a tobacco endoplasmic reticulum ω-3 fatty acid desaturase (NtFAD3) gene, 3'-truncated, polyadenylated endo-NtFAD3 transcripts and 5'-truncated, intron-containing endo-NtFAD3 transcripts were detected in the total RNA fraction. Although transcription proceeded until the last exon of the endogenous NtFAD3 gene, intron-containing NtFAD3 transcripts accumulated in the nucleus of the S-PTGS plants. Several intron-containing NtFAD3 transcripts harboring most of the exon sequences were generated when an endogenous silencing suppressor gene, rgs-CaM, was overexpressed in the S-PTGS plants. These intron-containing NtFAD3 splice variants were generated in the presence of NtFAD3 siRNAs that are homologous to the nucleotide sequences of these splice variants. The results of this study indicate that the inhibition of endo-NtFAD3 gene expression is primarily directed via the alteration of splicing and not by cytoplasmic slicer activity. Our results suggest that the transgene and intron-containing endogenous counterpart genes are differentially suppressed in S-PTGS plants.