Synaptic structures and quantification of catecholaminergic axons in the nucleus tractus solitarius of the rat: Possible modulatory roles of catecholamines in baroreceptor reflexes

The synaptic organization in the nucleus tractus solitarius (NTS) of the rat at the level of the obex was examined by fluorescence and electron microscopy in 5 groups of animals: (1) normal control, (2) intraventricular injection of 5-OHDA, (3) intraventricular injection of 6-OHDA, (4) intracranial denervation of the IXth and Xth cranial nerves, and (5) intraventricular injection of 5-OHDA 48 h after intracranial denervation of the IXth and Xth cranial nerves.A dense network of catecholaminergic nerves was observed in the NTS and several catecholaminergic neurons were seen to be scattered in the lateral portion of the NTS. Nerve cells in the NTS were small in size (15–20 μm in diameter). In addition to ordinary axodendritic and axo-somatic synapses, serial synapses were occasionally encountered. The first presynaptic site in some of the serial synapses was identified as catecholaminergic by 6-OHDA treatment.After treatment with 5-OHDA, 2.4% of axon varicosities were identified as catecholaminergic by small dense-cored vesicles. After administration of 6-OHDA, 5.19% of dense degenerated axon varicosities were counted. After intracranial deafferentation of the IXth and Xth cranial nerves, 5.3% of dense degenerated axon varicosities were found. The total number of axon varicosities in 6800 sq.μm area was decreased by 9% after the injection of 6-OHDA and 11% after deafferentation of the IXth and Xth cranial nerves.At least 3 types of axons could be identified: (1) catecholaminergic axons with small dense-cored vesicles after 5-OHDA administration, (2) afferent axons from the IXth and Xth cranial nerves with small clear vesicles, and (3) axons with small clear vesicles probably originated from the supramedullary nucleus.The results of the present study suggest that catecholamines modulate reflex blood pressure regulation within the NTS of the rat.     

Clinical studies of intrarectal administration of 5-FU emulsion as an adjunct to surgical treatment for rectal cancer

Preoperative intrarectal administration of 5-FU emulsion was attempted as an adjuvant chemotherapy to surgery for rectal cancer. The drug concentrations of resected specimens were determined and histological examinations of them were carried out in order to evaluate the effect of anticancer drugs on the metastatic lymph nodes as well as on the primary tumors. 5-FU levels both in the regional lymph nodes and primary tumors of 18 patients with rectal cancer, who were given with the 5-FU emulsion (emulsion group) or 5-FU suppository (suppository group) intrarectally two hours before surgery, was found to be much higher in emulsion group than in suppository group. 46 patients with rectal cancer were treated preoperatively with intrarectal administration of 5-FU emulsion (25 cases) or 5-FU suppositories (21 cases) for a period of 10 days before surgery, and the histological effect of this regimen on the metastatic lesion in the lymph nodes, as well as in the primary tumor was examined. No detectable difference was found in the primary lesions between the emulsion group and the suppository group. In the metastatic lesions, however, the rate of effectiveness was higher in the emulsion group than in the suppository (68 percent versus 33 percent).     

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.