Localization of Click Trains and Speech by Cats: the Negative Level Effect

Although localization of sound in elevation is believed to depend on spectral cues, it has been shown with human listeners that the temporal features of sound can also greatly affect localization performance. Of particular interest is a phenomenon known as the negative level effect, which describes the deterioration of localization ability in elevation with increasing sound level and is observed only with impulsive or short-duration sound. The present study uses the gaze positions of domestic cats as measures of perceived locations of sound targets varying in azimuth and elevation. The effects of sound level on localization in terms of accuracy, precision, and response latency were tested for sound with different temporal features, such as a click train, a single click, a continuous sound that had the same frequency spectrum of the click train, and speech segments. In agreement with previous human studies, negative level effects were only observed with click-like stimuli and only in elevation. In fact, localization of speech sounds in elevation benefited significantly when the sound level increased. Our findings indicate that the temporal continuity of a sound can affect the frequency analysis performed by the auditory system, and the variation in the frequency spectrum contained in speech sound does not interfere much with the spectral coding for its location in elevation.     

Acoustic Cues for Sound Source Distance and Azimuth in Rabbits, a Racquetball and a Rigid Spherical Model

There are numerous studies measuring the transfer functions representing signal transformation between a source and each ear canal, i.e., the head-related transfer functions (HRTFs), for various species. However, only a handful of these address the effects of sound source distance on HRTFs. This is the first study of HRTFs in the rabbit where the emphasis is on the effects of sound source distance and azimuth on HRTFs. With the rabbit placed in an anechoic chamber, we made acoustic measurements with miniature microphones placed deep in each ear canal to a sound source at different positions (10–160 cm distance, ±150° azimuth). The sound was a logarithmically swept broadband chirp. For comparisons, we also obtained the HRTFs from a racquetball and a computational model for a rigid sphere. We found that (1) the spectral shape of the HRTF in each ear changed with sound source location; (2) interaural level difference (ILD) increased with decreasing distance and with increasing frequency. Furthermore, ILDs can be substantial even at low frequencies when distance is close; and (3) interaural time difference (ITD) decreased with decreasing distance and generally increased with decreasing frequency. The observations in the rabbit were reproduced, in general, by those in the racquetball, albeit greater in magnitude in the rabbit. In the sphere model, the results were partly similar and partly different than those in the racquetball and the rabbit. These findings refute the common notions that ILD is negligible at low frequencies and that ITD is constant across frequency. These misconceptions became evident when distance-dependent changes were examined.     

Diagnostic performance of computed tomography for parathyroid adenoma localization; a systematic review and meta-analysis

Abstract purposeTo perform a systematic review and meta-analysis of the sensitivity and positive predictive value (PPV) of CT for preoperative parathyroid localization in patients with primary hyperparathyroidism (pHPT), and subsequently compare the different protocols and their performance in different patient groups.Materials and methodsWe performed a search of the Embase, Pubmed and Cochrane Library databases to identify studies published between January 1, 2000 and March 31, 2016 investigating the diagnostic value of CT for parathyroid localization in patients with biochemical diagnosis of pHPT. Performance of CT was expressed in sensitivity and PPV with pooled proportion using a random-effects model. Factors that could have affected the diagnostic performance were investigated by subgroup analysis.ResultsThirty-four studies evaluating a total of 2563 patients with non-familial pHPT who underwent CT localization and surgical resection were included. Overall pooled sensitivity of CT for localization of the pathological parathyroid(s) to the correct quadrant was 73% (95% CI: 69–78%), which increased to 81% (95% CI: 75–87%) for lateralization to the correct side. Subgroup analysis based on the number of contrast phases showed that adding a second contrast phase raises sensitivity from 71% (95% CI: 61–80%) to 76% (95% CI: 71–87%), and that adding a third phase resulted in a more modest additional increase in performance with a sensitivity of 80% (95% CI: 74–86%).ConclusionCT performs well in localizing pathological glands in patients with pHPT. A protocol with two contrast phases seems to offer a good balance of acceptable performance with limitation of radiation exposure.     

Impact of adiposity and plasma adipocytokines on diabetic angiopathies in Japanese Type 2 diabetic subjects.

AIMS: Adipocytokines, products from adipose tissue, have biological activities on the vascular system, and may affect diabetic angiopathy. In this study, we assessed the relationship between adiposity and plasma adipocytokine levels, and investigated the clinical significance of adiposity and plasma adipocytokine levels on diabetic micro- and macroangiopathy in Type 2 diabetic subjects. METHODS: We studied 231 Japanese Type 2 diabetic subjects (135 men and 96 women, aged 60.4 +/- 12.3 years, body mass index 24.8 +/- 5.2 kg/m2). We measured adipocytokine [adiponectin, leptin, resistin, and tumour necrosis factor (TNF)-alpha] levels, lipid profiles and urine albumin excretion. We also performed optic fundus examination and measured carotid intramedia thickness (IMT) using B-mode ultrasonography, and the localization of fat with abdominal computed tomography. A group of 93 subjects with microalbuminuria or overt proteinuria was compared with the other 148 to assess the effect on nephropathy. A group of 191 eyes with simple retinopathy or more advanced changes was compared with 263 eyes without retinal changes to assess the effect on retinopathy. RESULTS: Plasma adiponectin level was negatively correlated with both visceral (r = -0.37, P < 0.01) and subcutaneous (r = -0.25, P < 0.01) fat areas. Resistin concentration was positively related with visceral fat area (r = 0.15, P < 0.05). Adiponectin concentration was positively correlated with age (r = 0.26, P < 0.01). TNF-alpha was correlated with IMT (r = 0.16, P < 0.05) after correction for age. Logistic regression analysis indicates a 4085 times greater chance of having retinopathy with a one unit increase in TNF-alpha (pmol/l) and a 30.64 times greater chance of having nephropathy with one unit increase in leptin (nmol/l). CONCLUSIONS: The present observations suggest that visceral and subcutaneous fat has an impact on microangiopathy as well as macroangiopathy, possibly through different adipocytokines.     

Arterial stimulation with simultaneous venous sampling for localizing insulinomas

Purpose: The present study aimed to assess the accuracies of arterial stimulation with simultaneous venous sampling (ASVS) in preoperative localization of insulinomas.Materials and Methods: A cohort consisting of 6 males and 14 females (median age, 48.5y; range, 28–62y) with pathologically proven insulinomas were included in this study. Selective angiographies were performed with the superior mesenteric artery (SMA), gastroduodenal artery (GDA), proximal splenic artery, and midsplenic artery in all individuals. Then ASVS procedures were followed after angiographies for these arteries. Clinical characteristics of the patient and the tumor number, location, and size were recorded. The accuracy of preoperative localization of insulinomas was tested.Results: A total of 22 tumors were identified by histopathological diagnosis. The mean size of the tumor was 1.40±0.60cm. Five tumors were in the head/neck region and 17 in the body/tail region. ASVS accurately localized 17/20 (85%) cases with only biochemical data and 19/20 (95%) cases with biochemical data and angiography images. Variant pancreatic arterial anatomy was revealed in 2 false cases with inferior pancreatic artery replaced by the superior mesenteric artery.Conclusion: ASVS was highly accurate in localizing insulinomas and should be performed in most of the patients with suspected insulinomas before the operation.     

雷公藤内酯醇的细胞内定位研究?

目的：检测雷公藤内酯醇的细胞内定位,探讨其在细胞内的作用位点。方法采用4-溴甲基-7-甲氧基香豆素标记雷公藤内酯醇,与人肝癌细胞孵育;并与细胞核染料 PI 或细胞质膜染料 DiI 行双色荧光染色,用荧光显微镜观察。结果与对照相比,香豆素标记在紫外激发下呈特异性的淡蓝色荧光;与 DiI 共定位显示,香豆素标记在细胞质(膜)存在;与 PI 共定位显示,香豆素标记在细胞核存在,且荧光强于细胞质(膜)。结论雷公藤内酯醇在细胞内主要位于细胞核,其次是细胞质(膜),提示雷公藤内酯醇可能主要在细胞核内起作用,其次是在细胞质(膜)上起作用。     

Comparative biodistribution in mice of cyanine dyes loaded in lipid nanoparticles

Two near infrared cyanine dyes, DiD (1,1′-dioctadecyl-3,3,3′,3′-tetramethylindotricarbocyanine perchlorate) and ICG (Indocyanine Green) were loaded in lipid nanoparticles (LNP). DiD-LNP and ICG-LNP presented similar physicochemical characteristics (hydrodynamic diameter, polydispersity, zeta potential), encapsulation efficiency, and colloidal stability when stored in PBS buffer. However, whereas DiD had similar biodistribution than cholesteryl-1-¹⁴C-oleate ([¹⁴C]CHO, a constituent of the nanoparticle used as a reference radiotracer), ICG displayed a different biodistribution pattern, similar to that of the free dye, indicative of its immediate leakage from the nanovector after blood injection. NMR spectroscopy using Proton NOE (Nuclear Overhauser Effect) measurements showed that the localization of the dye in the lipid nanoparticles was slightly different: ICG, more amphiphilic than DiD, was found both inside the lipid core and at particle interface, whereas DiD, more hydrophobic, appeared exclusively located inside the particle core. The ICG release rate from the particles was 7% per 1 month under storage conditions (4 °C, dark, 10% of lipids), whereas no leakage could be detected for DiD. ICG leakage increased considerably in the presence of BSA 40 g/L (45% leakage in 24 h at 100 mg/mL of lipids), because of the high affinity of the fluorophore for plasma proteins. On the contrary, no DiD leakage was observed, until high dilution of the nanoparticles which triggered their dissociation (45% leakage in 24 h at 1 mg/mL of lipids). Altogether, the subtle difference in dye localization into the nanoparticles, the partial dissociation of the LNP in diluted media, and more importantly the high ICG affinity for plasma proteins, accounted for the differences observed in the fluorescence biodistribution after tail vein injection of the dye-loaded nanoparticles.     

低频小探头超声内镜对胰腺内分泌肿瘤术前定位诊断的价值

目的 评价低频小探头超声内镜检查(LFMPS)在胰腺内分泌肿瘤术前定位诊断中的临床价值。方法 2000年6月至2002年6月期间21例临床拟诊为胰腺内分泌肿瘤的患者术前行腹部 B超、螺旋 CT、磁共振(MRI)及 LFMPS探查(Fujinon 7.5 MHz低频小探头超声及超声系统),检查结果与外科术中定位和病理结果对照,评估LFMPS对胰腺内分泌肿瘤的术前定位诊断价值。结果21例患者中17例经外科手术及术后病理证实为内分泌肿瘤,4例未手术。其中胰岛素瘤16例(头部9例、体部 3例、尾部4例),胰腺外血管活性肠肽瘤1例,检出病灶的平均直径 2.02 cm。LFMPS确诊14例(82.4％),B超确诊9例(52.9％),螺旋CT确诊15例(88.2％),MRI确诊12例(70.6％),其中LFMPS对位于胰腺头、体部肿瘤以及直径<1cm病灶的确诊率优于其他常规影像方法。结论LFMPS对胰腺内分泌肿瘤的术前定位诊断准确率较高,且与肿瘤的位置与大小有关。