Effects of degree and symmetricity of bilateral spectral smearing, carrier frequency, and subject sex on amplitude of evoked auditory steady-state response signal.

The characteristics of an auditory steady-state response (ASSR) signal can be affected by the pathophysiological statuses of the left and right ears, such as a smeared sensation by native spectral smearing owing to sensorineural hearing impairment, because they can affect the perception of the stimulus, the degree of concentration on the stimulus and comfort in concentration. However, to date, few studies have examined the effects of such smeared sensations on the amplitude of the evoked ASSR signal. In this study, we synthesized various auditory stimuli with different degrees of spectral smearing using a hearing loss simulator to match the age of participant groups with different degrees of spectral smearing. We then performed three subjective tests, representing symmetric and asymmetric bilateral spectral smearing, with 16 normal-hearing individuals to observe the effects of the severity and symmetricity of bilateral spectral smearing, the value of the carrier frequency of auditory stimuli, and the sex of the individual on the amplitude in evoked ASSR signals. The experimental results demonstrated the following: (1) the application of spectral smearing to normal sounds may result in amplitude-reduced ASSR signals, (2) the effect of spectral smearing on the amplitude of the ASSR signals is most significant when the degrees of bilateral spectral smearing are asymmetric, (3) the selection of carrier frequency in an auditory stimulus can affect the amplitude of evoked ASSR signals regardless of the degree of spectral smearing, and (4) the sex of the individual can affect the amplitude of the evoked ASSR signal in various test conditions. The results of this study can help estimate the effects of smeared sensation by spectral smearing owing to sensorineural hearing impairment on the amplitude of evoked ASSR signals.

Effects of spectral smearing of stimuli on the performance of auditory steady-state response-based brain-computer interface.

There have been few reports that investigated the effects of the degree and pattern of a spectral smearing of stimuli due to deteriorated hearing ability on the performance of auditory brain-computer interface (BCI) systems. In this study, we assumed that such spectral smearing of stimuli may affect the performance of an auditory steady-state response (ASSR)-based BCI system and performed subjective experiments using 10 normal-hearing subjects to verify this assumption. We constructed smearing-reflected stimuli using an 8-channel vocoder with moderate and severe hearing loss setups and, using these stimuli, performed subjective concentration tests with three symmetric and six asymmetric smearing patterns while recording electroencephalogram signals. Then, 56 ratio features were calculated from the recorded signals, and the accuracies of the BCI selections were calculated and compared. Experimental results demonstrated that (1) applying smearing-reflected stimuli decreases the performance of an ASSR-based auditory BCI system, and (2) such negative effects can be reduced by adjusting the feature settings of the BCI algorithm on the basis of results acquired a posteriori. These results imply that by fine-tuning the feature settings of the BCI algorithm according to the degree and pattern of hearing ability deterioration of the recipient, the clinical benefits of a BCI system can be improved.

Effects of the simultaneous application of nonlinear frequency compression and dichotic hearing on the speech recognition of severely hearing-impaired subjects: simulation test.

OBJECTIVES: The clinical effects of the simultaneous application of nonlinear frequency compression and dichotic hearing on people with hearing impairments have not been evaluated previously. In this study, the clinical effects of the simultaneous application of these two techniques on the recognition of consonant-vowel-consonant (CVC) words with fricatives were evaluated using normal-hearing subjects and a hearing loss simulator operated in the severe hearing loss setting. METHODS: A total of 21 normal-hearing volunteers whose native language was English were recruited for this study, and two different hearing loss simulators, which were configured for severe hearing loss in the high-frequency range, were utilized. The subjects heard 82 English CVC words, and the word recognition score and response time were measured. RESULTS: The experimental results demonstrated that the simultaneous application of these two techniques showed almost even performance compared to the sole application of nonlinear frequency compression in a severe hearing loss setting. CONCLUSION: Though it is generally accepted that dichotic hearing can decrease the spectral masking thresholds of an hearing-impaired person, simultaneous application of the nonlinear frequency compression and dichotic hearing techniques did not significantly improve the recognition of words with fricatives compared to the sole application of nonlinear frequency compression in a severe hearing loss setting.

Acute pancreatitis due to a duodenal ulcer.

Duodenal ulcers and acute pancreatitis are two of the most commonly encountered gastrointestinal diseases among the general population. However, duodenal ulcer-induced pancreatitis is very rarely reported worldwide. This report elaborates on a distinct medical treatment that contributes to partial or complete treatment of acute pancreatitis induced by a duodenal ulcer scar.

A case of midazolam anaphylaxis.

Midazolam is a type of anesthetic agent frequently used for conscious sedation during a variety of medical procedures. Anaphylactic reactions to midazolam are rarely reported. However, we observed a case of midazolam hypersensitivity in which emergency measures were required to ensure patient recovery after administration of midazolam as a sedative. The occurrence of the anaphylactic reaction to midazolam was confirmed by elevated serum tryptase levels. The current case report presents a discussion of our findings.

Successful treatment of duodenal variceal bleeding by endoscopic clipping.

Duodenal varix bleeding is an uncommon cause of gastrointestinal bleeding in patients with portal hypertension but can cause severe and potentially fatal bleeding. However, the incidence is low and a good treatment method has not been well established yet. Duodenal variceal bleeding can be treated surgically or nonsurgically. We have successfully treated a patient with duodenal variceal bleeding secondary to liver cirrhosis using hemoclips to control the bleeding.

Dextran-b-poly(L-histidine) copolymer nanoparticles for ph-responsive drug delivery to tumor cells.

PURPOSE: Nanoparticles based on stimuli-sensitive drug delivery have been extensively investigated for tumor targeting. Among them, pH-responsive drug targeting using pH-sensitive polymers has attracted attention because solid tumors have an acidic environment. A dextran-b-poly(L-histidine) (DexPHS) copolymer was synthesized and pH-responsive nanoparticles were fabricated for drug targeting. METHODS AND RESULTS: A DexPHS block copolymer was synthesized by attaching the reductive end of dextran to the amine groups of poly(L-histidine). pH-responsive nanoparticles incorporating doxorubicin were fabricated and studied in HuCC-T1 cholangiocarcinoma cells. Synthesis of DexPHS was confirmed by 1H nuclear magnetic resonance spectroscopy, with specific peaks of dextran and PHS observed at 2-5 ppm and 7.4-9.0 ppm, respectively. DexPHS nanoparticles showed changes in particle size with pH sensitivity, ie, the size of the nanoparticles increased at an acidic pH and decreased at a basic pH. DexPHS block copolymer nanoparticles incorporating doxorubicin were prepared using the nanoprecipitation dialysis method. The doxorubicin release rate was increased at acidic pH compared with basic pH, indicating that DexPHS nanoparticles have pH-sensitive properties and that drug release can be controlled by variations in pH. The antitumor activity of DexPHS nanoparticles incorporating doxorubicin were studied using HuCC-T1 cholangiocarcinoma cells. Viability was decreased in cells treated with nanoparticles at acidic pH, whereas cell viability in response to treatment with doxorubicin did not vary according to changes of pH. CONCLUSION: Our results indicated that DexPHS polymeric micelles are promising candidates for antitumor drug targeting.

Clinical Outcomes of Bosniak Category IIF Complex Renal Cysts in Korean Patients.

PURPOSE: To assess the clinical reliability of the Bosniak IIF category and to determine the proper radiologic follow-up duration and intervals for category IIF complex renal cysts. MATERIALS AND METHODS: We studied 201 patients with category IIF renal cysts from January 1996 to January 2011. Renal cyst progression to category III was defined as an increase in complexity of the cyst in follow-up radiologic studies. We monitored radiologic changes and progression of renal cysts during the follow-up period and analyzed the pathologic results of those patients who were treated surgically. RESULTS: At a mean follow-up of 20 months, only 14 cases (7%) showed evidence of progression to stage III, with a mean time to progression of 11 months (range, 3 to 65 months). There were no significant differences in age, gender, cyst size, or change in cyst size between the progressive and non-progressive groups. Of 12 cases treated surgically, 10 cases (83.3%) showed renal cell carcinoma with pT1 stage, and there was no recurrence during postoperative follow-up of 23 months. Of the 187 patients without radiologic progression, 23 cases were treated surgically, and all of them showed benign cysts. CONCLUSIONS: The IIF category showed significant clinical reliability by a low rate of radiologic progression and a high rate of malignancy in the radiologic progressive group but a low rate of malignancy in the non-progressive group. Although it is hard to decide on a proper follow-up duration because of the variable time to progression, too frequent follow-up study seems to be unnecessary considering that most malignant cases were of a low stage.

A case of endoscopic treatment for gastrocolocutaneous fistula as a complication of percutaneous endoscopic gastrostomy.

As a rare complication of percutaneous endoscopic gastroscopy (PEG), a gastrocolocutaneous fistula may occur after PEG placement. This paper reports an interesting case which PEG tube unintentionally penetrated transverse colon during PEG. A 72-year-old female patient who suffered from medullary infarction underwent PEG procedure for enteral nutrition, and fecal materials were observed 6 days after the procedure. Transverse colon located in antero-superior site of stomach was observed through abdominal computed tomography, and also the wrong inserted tube was found through gastroscopy and colonoscopy. Endoscopic treatment for the fistula was performed by the use of hemo-clip and detachable snare, closure of the fistula was finally confirmed 6 days after the endoscopic procedure. Therefore, the gastrocolocutaneous fistula should be considered as one of the complications of PEG when fecal material is observed through PEG tube in a few days after PEG procedure and endoscopic treatment can be feasible in this case.

Retroperitoneoscopic partial nephrectomy in a horseshoe kidney.

A 21-year-old woman with a 4 cm enhancing cystic renal mass in the left moiety of a horseshoe kidney was treated through a retroperitoneal laparoscopic approach. The tumor was excised completely with cold scissors, and renal parenchyma suturing with a surgical bolster was done with Vicryl 2-0 sutures. Choosing the proper approach according to the location of the lesion and the surgeon's experience with both approaches are of importance in laparoscopic surgery in horseshoe kidney cases. A preoperative kidney computed tomography angiography was helpful for understanding the complex renal vasculature.

Effect of Shifting from Combination Therapy to Monotherapy of α-Blockers or 5α-Reductase Inhibitors on Prostate Volume and Symptoms in Patients with Benign Prostatic Hyperplasia.

PURPOSE: Combination therapy of α-blockers and 5α-reductase inhibitors (5-ARIs) is widely used for the treatment of benign prostatic hyperplasia (BPH). We aimed to study the effect on prostate volume and symptoms of shifting to monotherapy in patients who previously received a combination therapy. MATERIALS AND METHODS: A prospective study was conducted of 60 patients who were diagnosed with BPH. Patients were aged 45 years or older and had a prostate volume of 30 cc or more, International Prostate Symptom Score (IPSS) of 12 or above, maximal flow rate (Qmax) of 15 ml/s or less, and prostate-specific antigen (PSA) level of less than 10 ng/ml. The patients initially received a combination therapy of doxazosin 4 mg/day and finasteride 5 mg/day for 3 months and were then randomly assigned to receive monotherapy for 3 months. The factors were then compared. RESULTS: A total of 30 patients were assigned to doxazosin (group 1) and 30 to finasteride (group 2) after the combination therapy. The percentage changes in prostate volume, IPSS, and Qmax during the period from post-combination therapy to post-monotherapy were not significantly different between the two groups (p=0.052, 0.908, 0.081), whereas PSA significantly decreased in group 2 (p<0.001). IPSS was not significantly different at post-combination therapy and at post-monotherapy in both groups (p=0.858, 0.071). The prostate volume significantly increased from 40.97 cc at post-combination therapy to 44.29 cc at post-monotherapy in group 1 (p=0.001) and insignificantly increased from 38.32 cc to 38.61 cc in group 2 (p=0.696). CONCLUSIONS: Although the duration of drug administration was short in this study, 5-ARI monotherapy could maintain the alleviated symptoms and reduce the risk of acute urinary retention and surgery due to prostate regrowth in BPH patients whose symptoms improved with combination therapy.

Usefulness of slimmer and open-cell-design stents for endoscopic bilateral stenting and endoscopic revision in patients with hilar cholangiocarcinoma (with video).

BACKGROUND: Although endoscopic bilateral metal stenting using a "stent-in-stent" method is currently used to treat patients with unresectable hilar cholangiocarcinoma, this method has limited application in cases of tight strictures or endoscopic revision in case of tumor recurrence, especially on the first stent (initial Y stent placed) side. OBJECTIVE: To evaluate the clinical efficacy of bilateral metal stenting with the use of a slimmer (7F), open-cell-design stent. DESIGN: Prospective, uncontrolled, single center. SETTING: Tertiary referral university hospital. PATIENTS: This study involved 34 patients with unresectable hilar cholangiocarcinoma (Bismuth type II-IV). INTERVENTION: Endoscopic bilateral metal stenting using a stent-in-stent method was performed. First, a Y stent with a central, wide-open mesh was inserted, then a Zilver stent, with a preloaded delivery system that is slimmer (7F) than those (7.5-8.5F) of conventional stents, was placed into the contralateral hepatic duct through the central portion of the Y stent. The Zilver stent has an open-cell design, and it can be dilated easily. Thus, revision with bilateral plastic stents was tried in cases of stent obstruction. MAIN OUTCOME MEASUREMENTS: Technical success, functional success, complications, and revision method. RESULTS: Technical success (bilateral stenting using Y and Zilver stents) was achieved in 29 of 34 (85.3%) patients. Functional success was noted in 29 of the 29 (100.0%) patients who received bilateral stenting. Early complications such as pancreatitis and cholecystitis occurred in 3 (10.3%) patients. Late complications occurred in 11 (37.9%) patients. Cholecystitis, which occurred in 2 patients, was managed by percutaneous transhepatic gallbladder drainage. Stent obstruction by tumor ingrowth or overgrowth occurred in 9 of 29 (31.0%) patients. These patients were managed by placement of bilateral plastic stents (4 of 9), percutaneous transhepatic biliary drainage (4 of 9), and a combined method (1 of 9). Of the 5 patients in whom endoscopic revision was attempted, 4 (80%) were managed endoscopically with bilateral plastic stents. LIMITATIONS: Small number of patients, uncontrolled study. CONCLUSION: A slimmer (7F), open-cell-design stent is effective in endoscopic bilateral stenting for advanced hilar cholangiocarcinoma and endoscopic revision in case of tumor recurrence.