Circular dichroism of soybean trypsin inhibitor and its derivatives

Circular dichroism (CD) of soybean trypsin inhibitor (STI, the ?KUNITZ inhibitor”?)and some of its derivatives was studied in the spectral region of 185 to 320 mμ. Acetylation and succinylation, as well as denaturation with 6 M guanidine hydrochloride resulted in small changes in the CD spectra. In strongly acid solutions at pH 1.8 to 2.0 was observed a decrease of the amplitude of the positive COTTON effect at 226 mμ and a shift of this band to 230 mμ. Remarkable changes were observed in the CD spectra after cleavage of the disulfide bonds of STI either by reduction or sulfitolysis. The positive band at 226 mμ thereby disappeared, the negative bands around 240–300 mμ were modified and the amplitude of the strong negative COTTON effect at 200 mμ was diminished by the cleavage of the disulfide bonds. Reconstitution of the disulfide bonds lead to CD patterns resembling those of the native protein. The antitryptic activity of all chemically modified samples was significantly lowered.     

Diagnosis of nasopharyngeal carcinoma metastatic to mediastinal lymph nodes by endoscopic ultrasonography-guided fine-needle aspiration biopsy

We report the case of a patient with nasopharyngeal carcinoma who was diagnosed as having metastasis in mediastinal lymph nodes and successfully underwent systemic chemotherapy without surgery. A 61-year-old male with a history of nasopharyngeal carcinoma presented with odynophagia. Examination revealed two palpable lymph nodes in the right neck. Pharyngoscopy showed a mass in the left inferior pharyngeal mucosa, and upper gastrointestinal endoscopy showed only chronic gastritis, with no sign of esophageal disease. Chest CT confirmed the presence of a non-enhancing 20-mm soft tissue mass in the paraesophageal area, with increased attenuation compared with the adjacent esophagus. To evaluate this lesion we applied endoscopic ultrasonography-guided fine-needle aspiration biopsy (EUS-FNA). Two passes were made with a 21-gauge fine needle and the patient tolerated the procedure well, without complications. Cytological findings were compatible with metastatic squamous cell carcinoma from a nasopharyngeal tumor, and the clinical stage was determined as T3N2bM1 (stage IVC) because of mediastinal lymph node metastasis. We thus determined the nodal status of a head and neck tumor by means of EUS-FNA. In conclusion, EUS-FNA is a safe and reliable technique for evaluation of mediastinal lymphadenopathy, and is especially valuable for head and neck tumors with suspected metastasis.     

Rabbit model of airway stenosis induced by scraping of the tracheal mucosa

BACKGROUND: Prolonged endotracheal intubation in children often induces intractable airway stenosis. The aim of the present study was to establish a new model of airway stenosis for developing an effective method of treatment. MATERIAL AND METHODS: The rabbit trachea was annularly incised, and the tracheal mucosa was scraped with a nylon brush. The trachea was then closed. Nine days after scraping, the trachea was microscopically examined. RESULTS: All of the examined rabbits showed tracheal stenosis, ranging from 22% to 82% in diameter and from 48% to 97% in cross-sectional area. The stenotic lesion was confined within the scraped region, not including the sutured region. Histologic examination showed inflammation in the stenotic lesion with submucosal hyperplasia caused by proliferation of fibroblasts and thickening of collagen fibers. CONCLUSION: This method can be easily carried out and assures induction of airway stenosis. This model may be useful for developing methods for treating airway stenosis in the early stage.     

Clinicopathologic study of non-Hodgkin lymphoma in sinonasal and hard palate regions in 15 Japanese cases

Non-Hodgkin lymphomas of the sinonasal region have been the subject of numerous studies. Previous reports have suggested that nasal lymphomas occurring in Orientals are mostly of the natural killer cell (NK)/T-cell phenotype which contrasts with the preponderance of the B-cell type in western populations. Recent studies indicated that NK/T-cell lymphoma constitutes the clinical condition of lethal midline granuloma. These reports led us to question whether all NK/T lymphomas are always lethal midline granuloma. We have investigated a series of 15 cases of non-Hodgkin lymphomas in the nasal and/or paranasal sinuses clinically, immunohistochemically and for the presence of Epstein-Barr virus (EBV). This study showed that the presence of EBV was common in nasal NK/T lymphoma, and this type of lymphoma was clearly highly frequent in other types of nasal lymphoma in our department. Moreover, in 4 cases of NK/T-cell lymphomas, the clinical features of lethal midline granuloma did not appear, indicating that NK/T lymphomas are not always lethal midline granuloma.     

Hearing loss in patients with enlarged vestibular aqueduct: air-bone gap and audiological Bing test

The Bing test is based on the principle that occlusion of the external auditory meatus improves the perception of bone-conducted sounds unless there is a conductive hearing impairment. An air-bone gap has been reported in patients with large vestibular aqueduct (LVA) syndrome without apparent middle ear dysfunction. We therefore performed the Bing test on nine patients with this syndrome to evaluate whether it is associated with an air-bone gap or middle ear dysfunction. Bone conduction thresholds did not change significantly during the Bing test in any patient. Because an air-bone gap is observed in patients with abnormal communication between the inner ear and cerebrospinal fluid through the LVA, dehiscent superior canal, or dilated inner ear meatus; we propose that a 'three windows' model (in which the abnormal communication provided by the enlarged endolymphatic duct and sac in LVA acts as the 'third window' for sound conductance) might explain the air-bone gap in such patients.     

Biocompatible inkjet printing technique for designed seeding of individual living cells

Inkjet printers are capable of printing at high resolution by ejecting extremely small ink drops. Established printing technology will be able to seed living cells, at micrometer resolution, in arrangements similar to biological tissues. We describe the use of a biocompatible inkjet head and our investigation of the feasibility of microseeding with living cells. Living cells are easily damaged by heat; therefore, we used an electrostatically driven inkjet system that was able to eject ink without generating significant heat. Bovine vascular endothelial cells were prepared and suspended in culture medium, and the cell suspension was used as "ink" and ejected onto culture disks. Microscopic observation showed that the endothelial cells were situated in the ejected dots in the medium, and that the number of cells in each dot was dependent on the concentration of the cell suspension and ejection frequency chosen. After the ejected cells were incubated for a few hours, they adhered to the culture disks. Using our non-heat-generating, electrostatically driven inkjet system, living cells were safely ejected onto culture disks. This microseeding technique with living cells has the potential to advance the field of tissue engineering.     

Side-to-side linking of myocardial cells in hypertrophic cardiomyopathy: whole heart microscopic observation with tangential sections

By cross-section or longitudinal section, it is difficult to investigate longitudinal features of myocardial cells in the whole heart. Here, introducing the use of tangential sections to obtain longitudinal aspect of myocardial cells in any part of myocardium, the authors evaluated myocardium in the left ventricle in 10 normal hearts and four hearts with hypertrophic cardiomyopathy (HCM). Tangential sections were obtained by peeling the superficial layer of myocardium. After peeling the whole surface, secondary deep layer was peeled. These procedures were repeated more than five times through the wall. Intercalated discs (ICD) were observed immunohistochemically with anti-N-cadherin and antidesmoplakin. In normal hearts, myocardial cells were cut longitudinally and ran parallel in tangential sections. They linked end-to-end with simple and regular ICD with average lengths of 120-130 microm and average sarcomere numbers of 56-65. In HCM hearts, many myocardial cells were cut almost longitudinally running approximately parallel in tangential sections. Myocardial cells frequently showed side-to-side linking characterized by skewed ICD, indistinct ICD counterparts, and longitudinally arranged ICD. Two young HCM hearts had circle-shaped ICD and vacuole-like structures highlighted by immunostaining for N-cadherin, which were actually extracellular structures comparable with irregular side-to-side linking. It is considered that side-to-side linking of myocardial cells is a characteristic microscopic feature in HCM rather than myocardial disarray.     

In vivo degradability of hydrogels prepared from different gelatins by various cross-linking methods

This study is an investigation to evaluate the in vivo degradation of gelatin hydrogels in terms of their number of cross-links. Various hydrogels were prepared from acidic gelatin, extracted from bovine bone, porcine skin or fish scale, and basic gelatin, extracted from porcine skin, through four types of cross-linking methods, i.e., glutaraldehyde (GA) or dehydrothermal treatment and ultraviolet (UV) or electron beam irradiation. The water content of hydrogels and their number of cross-links, calculated from the tensile modulus of hydrogels, were evaluated as the measure of hydrogel cross-linking extent. Following subcutaneous implantation of 125I-labeled gelatin hydrogels into mice, the radioactivity remaining was measured at different time intervals to assess the in vivo degradability of hydrogels. Irrespective of the gelatin type and cross-linking method, a good correlation was found between the in vivo degradability of hydrogels and their number of cross-links, which is different from the correlation to their water content. This finding indicates that the degradability of hydrogels is governed by their number of cross-links.     

The sensorimotor transformation of cross-modal spatial information in the anterior intraparietal sulcus as revealed by functional MRI

The parietal cortex in monkeys and humans has been shown to play an important role in the transformation of sensory information to motor commands. However, it is still unclear whether in humans, these areas are divided functionally into subregions based on different combinations of sensory and motor modalities. To identify subregions in the parietal cortex involved in the sensorimotor information transformation between different modalities, functional MRI was used to examine brain areas activated during tasks requiring different sensorimotor transformations--i.e., various combinations of eye (saccade) or finger movements triggered by visual or somatosensory cues. We then compared the activations between cross-modal conditions (eye movements triggered by somatosensory cues and finger movements triggered by visual cues) and intramodal (eye movements triggered by visual cues and finger movements triggered by somatosensory cues) conditions. Although the parietal cortex was involved in all tasks regardless of sensorimotor combinations, the only region activated to a greater degree in the cross-modal conditions compared to the intramodal conditions was the anterior portion of the intraparietal sulcus (a-IPS). The results suggest that the a-IPS plays an important role in the sensorimotor transformation of cross-modal spatial information.