Functional neuroanatomy of speech processing within the temporal cortex

The phonemic structure of the maternal language determines the way of perceiving speech signals. A typical example is that native Japanese listeners map two English phonemes, /r/ and /l/, onto the same /R/. This perceptual assimilation of speech sounds has been associated with the left and/or right posterior perisylvian region, but the precise functional anatomy is unknown. Using functional magnetic resonance imaging and a repetition priming paradigm, we identified three subregions in the left temporal cortex: an anterior division sensitive to language-specific phonological knowledge, and a midlateral and a posterior division related to other vocal stimuli features. Dynamic causal modeling supports the scheme by which the anterior pathway processes perceptual assimilation; the posterior pathway processes lexico-semantic information.     

Difference of ITS sequences of Akebia plants growing in various parts of Japan

The stem of the Akebia plant, “Mokutsu”, is a crude diuretic and antiphlogistic drug. Japanese products prepared from wild Akebia plants cover most of the Mokutsu market. Two Akebia plants, Akebia quinata Decaisne (Aq) and A. trifoliata Koidzumi (At) of Lardizabalaceae, are standardized as Mokutsu in Japanese pharmacopoeia. These two Akebia plants along with A. × pentaphylla Makino (Ap), which is considered a hybrid with the morphology of Aq and At, can be distinguished by DNA sequence analysis of internal transcribed spacers 1 and 2 (ITS) of nuclear ribosome DNA. Here, we report the results of molecular genetic analysis of Akebia plants grown in various wild habitats in Japan. We found that each of three Akebia plants could be distinguished in terms of their locality according to their nucleotide sequence in ITS, specifically at positions 91, 128, 133, 134, and 221. Plants with a comparable habitat had similar nucleotide sequences at these five points. We also found Aq with ITS and nucleotide deletion at position 86 that was distributed only around Awajishima in Shikoku (A), Harimanada (B), and Kinki (C), including the chief production center of Akebia Caulis. The results of these ITS sequences enabled discrimination of plants originating from Akebia Caulis.     

Deletion of the core-H region in mice abolishes the expression of three proximal odorant receptor genes in cis

We have previously reported that a 2.1-kb homology (H) sequence, conserved between mouse and human, regulates the odorant receptor (OR) gene MOR28 in transgenic mice. Here, we narrowed down the essential sequences of the H to a core of 124 bp by using a transient expression system in zebrafish embryos. Transgenic experiments in mice demonstrated that the core-H sequence is sufficient to endow expression of the MOR28 minigene. Deletion and mutation analyses of the core-H region revealed two homeodomain sequences to be essential for the H enhancer activity. Targeted deletion of the core-H abolished expression of three proximal OR genes, MOR28, MOR10, and MOR83, in cis, indicating the presence of another locus control region/enhancer in the downstream region, that regulates four distal OR genes in the same MOR28 cluster. In the heterozygous mice, the H(-) phenotype of the mutant allele was not rescued by the wild-type H(+) allele in trans.     

MR imaging of the female pelvis at 3 Tesla: evaluation of image homogeneity using different dielectric pads

PURPOSE: To evaluate improvements in image homogeneity in pelvic MR imaging at 3 Tesla (T) using two different dielectric pads. MATERIALS AND METHODS: A total of eight healthy females were scanned using a 3T MR scanner equipped with a body-array coil. Axial and sagittal fast spin-echo T2-weighted images (T2WI) (TR/TE = 3200 msec/94 msec), axial fast spin-echo T1-weighted images (T1WI) (TR/TE = 700 msec/11 msec), and sagittal half-Fourier acquisition single-shot turbo spin-echo (HASTE) images (TR/TE = 3000 msec/100 msec) were performed for pelvic imaging. Sequences were repeated with dielectric pads (consisting of either ultrasound [US] gel or water), and without pads. Three or four regions of interest (ROIs) were placed on fatty tissues and the ratio of minimum to maximum signal intensity (RSI) was calculated as a marker of image homogeneity. RESULTS: RSI was significantly higher on T2WI and T1WI when using dielectric pads than when no pad was used. A similar tendency was observed in RSI on HASTE. No significant difference was found between images with US gel pads and those with water pads. CONCLUSION: Dielectric pads consisting of either US gel or water are effective in improving image homogeneity of the pelvis on 3T MRI.     

MRI of the female pelvis at 3T compared to 1.5T: evaluation on high-resolution T2-weighted and HASTE images

Purpose

To evaluate the feasibility of MRI of the female pelvis using high‐resolution T2‐weighted imaging (T2WI) and the half‐Fourier acquisition single‐shot turbo spin‐echo (HASTE) technique at 3 Tesla (T) compared to 1.5T, while focusing on the uterine body and cervical anatomy.

Materials and Methods

A total of 19 healthy women underwent pelvic MR scans on 3T and 1.5T scanners. Axial and sagittal T2W (voxel size of 0.6 × 0.8 × 2 mm) and sagittal HASTE images were obtained. The images were evaluated qualitatively for overall image quality, contrast in the uterine zonal appearance and cervical structure, image inhomogeneity, and artifacts. A quantitative evaluation was performed regarding zonal contrast and image inhomogeneity.

Results

On T2WI, the image contrast in the uterine cervix and vagina were significantly higher at 3T than at 1.5T, although there was no significant difference in the overall image quality or contrast in the uterine zonal appearance. Image inhomogeneity was more prominent at 3T, and motion artifact was more severe at 1.5T.

Conclusion

Our results suggest that MRI of the female pelvis at 3T may potentially provide excellent images of the uterine cervix on high‐resolution T2WI. New techniques to reduce inhomogeneity are thus called for. J. Magn. Reson. Imaging 2007;25:527–534. © 2007 Wiley‐Liss, Inc.     

Two cases of epidural anesthesia using ultrasound imaging

We report two cases of epidural anesthesia in an 11-year-old obese girl (BMI 34.5) using ultrasound imaging by an inexperienced resident. It was useful for performing epidural anesthesia in these difficult cases to observe anatomical structure around epidural space and to measure the angle and distance from the skin to the epidural space. The distances in ultrasound imaging and actual puncture in case 1 were 171 mm and 250 mm, and in case 2 these were 439 mm and 480 mm, respectively. In both cases, epidural puncture was performed smoothly at the first attempt and there was no adverse effect. We conclude that using ultrasound imaging before epidural puncture in obese children is safer and more educational for residents.     

A false positive for metastatic lymph nodes in the axillary region of a breast cancer patient following mastectomy

Recent advanced imaging modalities such as positron emission tomography (PET) detect malignancies using 2-[18F]-fluoro-2-deoxy-d-glucose (18-FDG) with high accuracy, and they contribute to decisions regarding diagnosis, staging, recurrence, and treatment response. Here, we report a case of false-positive metastatic lymph nodes that were diagnosed by PET/CT and ultrasonography in a 48-year-old breast cancer patient who had undergone mastectomy. The tumors, which were oval shaped and resembled lymph nodes, were detected by ultrasonography. PET/CT revealed high uptake of 18-FDG in the tumors. To investigate the proposed recurrence and to re-evaluate the biology of the recurrent tumors, a tumor was removed from the brachial plexus of the patient. Histological findings revealed it to be a schwannoma. All imaging modalities including PET/CT failed to distinguish benign tumors from metastatic lymph nodes in the brachial plexus. After resection of the schwannomas, the patient complained of a slight motor disorder of the second finger on the right hand. Hence, it is important to consider a false-positive case of lymph node metastasis in a breast cancer patient following mastectomy.     

Antioxidant effects of a dietary supplement: Reduction of indices of oxidative stress in normal subjects by water-soluble chitosan

The effect of water-soluble chitosan, a natural polymer derived from chitin, on indices of oxidative stress was investigated in normal volunteers. Treatment with chitosan for 4 weeks produced a significant decrease in levels of plasma glucose, atherogenic index and led to increase in high density lipoprotein cholesterol (HDL). Chitosan treatment also lowered the ratio of oxidized to reduced albumin and increased total plasma antioxidant activity (TPA). There was good correlation between TPA and oxidized albumin ratio. The results indicate that oxidized albumin ratio represents a potentially useful marker of oxidative stress. In in vitro studies, albumin carbonyls and hydroperoxides were significantly decreased in a time-dependent manner in the presence of chitosan, compared with controls (p < 0.05). Chitosan also reduced two stable radicals in a dose- and time-dependent manner. The results suggest that chitosan has a direct antioxidant activity in systemic circulation by lowering the indices of oxidative stress in both in vitro and in vivo studies. This may confer benefits additional to the reduction in plasma carbohydrate and increase in HDL levels. It may also inhibit oxidation of serum albumin commonly observed in patients undergoing hemodialysis, resulting in reduction of oxidative stress associated with uremia.     

A case successfully treated by desensitization for paclitaxel-associated hypersensitivity reactions

We report a case of a 56-year-old woman with hypersensitivity reactions (HSRs) symptoms against paclitaxel (PTX) which were suppressed by pre-injection of a low-dose of PTX before the full-dose injection. She received PTX chemotherapy (120 mg/body/week for three weeks on the 1st, 8th, and 15th day, followed by no drug for one week) in October 2004 for right breast cancer. However, continuation of the therapy was in jeopardy due to respiratory difficulties and facial flushing, considered to be HSRs symptoms, on day 15. However,we were able to continue the PTX chemotherapy by administering a low-dose pre-injection (2 mg/100 mL/30 min) before the full-dose injection. After that, HSRs symptoms were observed, but we were able to administer another low-dose pre-injection (1 mg/100 mL/30 min). Three courses of chemotherapy were successfully performed, followed by radical surgery in February 2005. A pathological complete response (pCR) of the maintumor was achieved. We suggest that pre-injection of a low-dose of PTX before the full-dose injection may be effective for prevention of the onset of HSRs symptoms.