Lesion site in sudden deafness: study with electrocochleography and transiently evoked otoacoustic emission

We examined electrocochleogram (ECochG) and transiently evoked otoacoustic emission (TEOAE) on five cases of sudden sensorineural hearing loss which had no abnormalities detected on diagnostic imagings and showed complete recovery of hearing. At the initial examination, three cases showed a broadened wave 1 with prolonged latency in the auditory brainstem response (ABR) at 90 dB HL. The ECochG AP showed a broad waveform, low amplitude, and high threshold. CM threshold, although increased, was relatively well preserved compared with hearing threshold measured with conventional pure-tone audiometry. The thresholds in TEOAE examination were similar to those for CM and preserved better when compared with pure-tone audiometric thresholds. These findings suggest that the location of the disorder in these three cases involved not only the cochlea but also the retrocochlear auditory pathway. The other two cases showed normal ABR waveforms at 90 dB HL at the initial examinations. ECochG examination showed that a normal AP in one case and a smaller amplitude AP, an elevated threshold, and normal waveform of AP in the other ear. CM thresholds coincided with the conventional audiometry thresholds. These findings suggest that hearing loss in these two cases involved primarily the sensory hair cells.

Screening for yeasts incorporating the exogenous eicosapentaenoic and docosahexaenoic acids from crude fish oil

The screening for yeasts incorporating exogenous eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) into their cellular lipids was conducted. Two percent of oil from fish scraps was added to a yeast isolation medium as a sole carbon source. From 143 soil samples, we isolated 23 yeast strains, nine of them were found to be capable of quickly assimilating the scrap fish oil. These nine strains, in addition to four previously isolated triglyceride-assimilating and lipase-producing strains, Yarrowia lipolytica and three Geotrichum species (FO274A, FO347-2 and FO401B), were cultured in a growth medium at 30 degrees C. Strains FO726A, FO765A and FO347-2 were selected on the basis of dry cell weight production and ability to store EPA and DHA in their cells, and their performance was further compared by varying cultivation temperature and time. From 1 g of the scrap fish oil, FO726A yielded 620 mg of dry cells, containing 47.1% lipid, 38.1% triglyceride, 3.3% EPA, and 4.9% DHA, when cultured at 25 degrees C for 36 h. Strain FO726A apparently has the highest ability to incorporate EPA and DHA into its cellular lipids. Results from further experiments showed that the incorporated EPA and DHA mainly existed in the form of triglyceride in the FO726A cell. These results suggest that FO726A is suitable for the production of cell mass rich in EPA and DHA for feed.

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst: delineation of surgical margins and reconstruction with bilateral rectus abdominis myocutaneous free flaps

A case of central carcinoma of the mandible arising from a recurrent odontogenic keratocyst is reported. A 38-year-old man was admitted to the Tokai University Hospital due to postoperative infection of a recurrent odontogenic keratocyst of the left mandible. He had had a cystectomy for an odontogenic keratocyst 4 years ago. The lesion revealed bony destruction of the mandible with worm-eating shaped margins with extension to the facial skin. A biopsy specimen revealed squamous cell carcinoma. The mandible was resected with facial skin and the sublingual space was dissected to preserve the lingual nerve. The oral and the facial resections were reconstructed with a titanium plate and bilateral rectus abdominis myocutaneous free flaps. The plate was removed due to infection around the margins and readjustment of the flaps was conducted 5 months after the surgery. He has not had a local relapse, metastasis, or incisional hernia for 8 months following surgery. Good occlusion has been attained by the residual mandible, and he is able to eat without any problems.

[Study of the fifth-type cell in the olfactory epithelium]

The olfactory epithelium has been shown to contain fifth-type cells and microvillar cells and olfactory receptor cells along with supporting and basal cells. However, the morphological differences among them are unknown, especially between the former two, and most of their functions are still unclear. In this study, the fifth-type cell and the microvillar cell in the olfactory epithelium of mouse were micromorphologically investigated by SEM and TEM. With the aim of elucidation their functions, the morphological change in these cells after resection of olfactory bulb were studied. In addition, the changes in the olfactory epihelium after HRP injections into the postganglionic fiber for the trigeminal nerve and the olfactory bulb were examined. The TEM observation revealed that the fifth-type cell has finger-like microvilli, which are strong and straight. The microvilli were characterized by a specific core structure consisting of microfilament bundles. On the other band, the microvilli of the microvillar cell were meandering and had no core structure, indicating that the two cells are clearly different types. By SEM observation, neither the fifth-type cell nor the microvillar cell was found in the normal olfactory epithelium. When the olfactory cillial mat disappeared as a result of recection of the olfactory bulb, the fifth-type cell became observable. On the 300th-day after the resection, it was found that the olfactory receptor cells had disappeared and the microvilli of the supporting cells were shortened. Thus, the surface structure of the microvillar cell became clearly observable. Then, the microvilli were found to be shorter than those of the fifth-type cell and were distributed radially. Neither the fifth-type cell nor the microvillar cell was not affected by resection of the olfactory bulb. Most of the olfactory vesicles were HRP positive after the HRP injection into the olfactory bulb; however, HRP was not detected in either the fifth-type cells or the microvillar cells. After the HRP injection into the trigeminal postganglionic fiber, it was detectable in part of the nerves in the lamina propria mucosa and the epithelal basement, but not in the fifth-type cell or microvillar cell. These results suggest that the fifth-type cell is a mechanoreceptor for a system other than the olfactory one and the microvillar cell is a kind of supporting cell in an early stage or final stage near death.

Evaluation of rheumatoid arthritis using a scoring system devised from magnetic resonance imaging of rheumatoid knees

We studied the magnetic resonance imaging (MRI) of 120 knees in 86 rheumatoid arthritis (RA) patients and of 14 unaffected knees in 12 control cases. We also developed a scoring system as a quantitative analysis method. We divided the MRI into 10 items, and classified the severity of the symptoms into 4 grades (score 0 to 3). The average total score increased according to the radiographic grade. Soft tissue lesions were clearly detected, even in the early stages of RA. Items such as synovial proliferation showed a high score even in the early stages, suggesting that it was the initial symptom of RA. The score also showed a correlation with the inflammatory signs. These results suggest that this scoring system is very sensitive and yields a good reflection of RA activity. We demonstrated that this system is simple and convenient for routine diagnostic use. We further demonstrated that it is useful for following the advancement of RA and for evaluating the response to treatment.

In situ expression of platelet-activating factor (PAF)-receptor gene in rat skin and effects of PAF on proliferation and differentiation of cultured human keratinocytes

Platelet-activating factor (PAF) is a potent lipid mediator that exhibits versatile biologic activities in many diverse systems by binding to a specific cell-surface receptor (PAFR). Although the production of PAF in cultured keratinocytes and fibroblasts has been reported, physiologic roles of this mediator in skin remain unclear. In this study, we examined in situ expression of PAFR gene in rat skin and the effects of PAF on the proliferation and differentiation of cultured human keratinocytes. In rat epidermis, PAFR mRNA expression was found from the basal cells to the granular cells, and strong signals were seen in the stratum spinosum. In cultured human keratinocytes, a 3.8 kb PAFR mRNA expression was demonstrated by northern blotting, and two distinct type transcripts driven by different promoters were detected by reverse transcriptase polymerase chain reaction analysis. Addition of PAF (30-100 nM) to cultured keratinocytes during a growth phase inhibited the proliferation. This effect was receptor dependent, because the inhibition was completely blocked by a PAFR antagonist, WEB 2086 (100 nM). On the other hand, whereas PAF (30-100 nM) alone did not affect the cornified envelope formation during the process of keratinocyte differentiation, WEB 2086 (30-300 nM) accelerated it in a concentration-dependent manner. Addition of PAF (100 nM) reversed the effect of WEB 2086, suggesting that WEB 2086 induced cornification by inhibiting PAF endogeneously produced by keratinocytes in an autocrine manner. Thus, we propose that PAF is an intrinsic regulator of keratinocyte during proliferation and differentiation.

Biological Species of Armillaria in Japan

Pairing tests with isolates of Armillaria in culture were used to identify species of Armillaria and their distribution throughout Japan. The existence of 10 intersterile groups of Armillaria was determined by pairing haploid single spore isolates obtained from 20 basidiocarps from a wide geographic distribution in Japan. Two to four haploid tester isolates from each intersterile group were then paired to biological and morphological species with haploid tester isolates from Europe and North America identified in previous studies. Japanese haploid tester isolates were then paired with 190 haploid or diploid isolates and compatibility reactions were used to identify these to species. Of the 10 intersterile groups identified in Japan, 7 were authenticated as A. gallica, A. nabsnona, A. ostoyae, A. cepistipes, A. mellea, A. sinapina, or A. tabescens. Three of the groups were not compatible with any of the tester species. The distribution and host relationships of the Japanese biological species are also discussed.

Supersensitivity of atherosclerotic artery to constrictor effect of cigarette smoke extract

OBJECTIVE

The aim of this study was to assess whether contractile response of arteries to aqueous component of cigarette smoke extract (CSE) may be modulated in atherosclerotic arteries.

METHODS

Thoracic aortas were isolated from control rabbits and from 1.5% cholesterol-fed rabbits, all of which had visible advanced atheromatous surface changes on the aortas. CSE was prepared by bubbling main stream of smoke from one cigarette with filter into 2 ml of phosphate-buffered saline. The thoracic aortic rings were suspended in organ chambers and tested with CSE (0.01-3.0 microliters/ml buffer in the organ chamber) after precontraction with 0.1 mumol/l of phenylephrine (PE).

RESULTS

The contractile response to CSE was significantly greater in atherosclerotic aortas than in control aortas (the maximal contraction expressed as % of the precontraction; control aortas 10.8 +/- 2.8%, atherosclerotic aortas 42.6 +/- 4.7%; P < 0.01). The magnitude of the precontractions by PE was not different between control and atherosclerotic aortas. Exogenous addition of superoxide dismutase (SOD) significantly attenuated the CSE-induced contraction in both control and atherosclerotic aortas and pretreatment of aortic rings with diethyldithiocarbamate to deplete of endogenous vascular CuZn-SOD activity potentiated the CSE-induced contraction in control aortas, while it had no significant effect in atherosclerotic aortas. The vascular SOD activity was significantly lower in atherosclerotic aortas than in control aortas ((U/mg protein): control aortas 38.2 +/- 3.3, atherosclerotic aortas 18.5 +/- 2.4; P < 0.01).

CONCLUSION

These results indicate that atherosclerotic arteries may be supersensitive to the constrictor effect of superoxide anion derived from CSE. The decrease in endogenous vascular SOD activity may partly contribute to the increased susceptibility to oxidative stress in atherosclerotic arteries.

Biphasic regulation of transcription factor nuclear factor-kappaB activity in human endothelial cells by lysophosphatidylcholine through protein kinase C-mediated pathway

Lysophosphatidylcholine (lysoPC), which is generated in oxidized LDL (Ox-LDL) and abundantly exists in atherosclerotic arterial walls, has been shown to alter various endothelial functions and induces several endothelial genes expressed in atherosclerotic arterial walls. Nuclear factor-kappa B (NF-kappaB), a pleiotropic transcription factor, plays an important role in regulation of expression of various genes implicated in atherosclerosis. We have previously reported that lysoPC transferred from Ox-LDL to endothelial surface membrane activates endothelial protein kinase C (PKC), leading to modulated endothelial functions. This study was aimed at determining whether lysoPC could modulate activity of transcription factors in cultured human umbilical vein endothelial cells (HUVECs) by using electrophoretic mobility shift assay. LysoPC was found to increase DNA-binding activity of NF-kappaB in HUVECs within 15 minutes, which peaked at 1 to 2 hours and subsequently declined to the baseline level at 6 hours. Lower concentrations (5 to 15 micromol/L) of lysoPC markedly increased NF-kappaB activity, but higher concentration (50 micromol/L) of lysoPC inhibited the activity. Phorbol 12-myristate 13-acetate, a potent activator of PKC, also augmented NF-kappaB activity in HUVECs, mimicking the effects of lysoPC; furthermore, calphostin C and chelerythrine chloride, specific PKC inhibitors, and alpha-tocopherol, a clinically potent PKC inhibitor, suppressed the lysoPC-induced NF-kappaB activation. These results indicate that lysoPC regulates NF-kappaB activity in a biphasic manner dependent on its concentrations and incubation time in human endothelial cells and the endothelial PKC activation may in part be involved in the lysoPC-induced NF-kappaB activation. Thus, the time course and the positive and negative biphasic regulatory actions of lysoPC on NF-kappaB activity in endothelial cells might exhibit a unique effect of lysoPC in arterial walls on the different stages of atherosclerosis.

[Binocular functions in amblyopia and strabismus]

Regarding the changing trends in the concept, definition, etiological classification, and criteria for diagnosis of amblyopia, we reviewed a total of 4,693 cases of amblyopia seen during the past 37 years. The amblyopia was divided into four types: strabismic, anisometropic, ametropic, and form vision deprivative. There was a definite trend for the incidence to decrease and for the diagnosis to be made during earlier age in recent years. Although favorable recovery of visual acuity is obtained after treatment of amblyopia and strabismus, there are difficulties in obtaining good binocular functions in early-onset amblyopia and strabismus. This feature was evaluated in regard to motion perception asymmetry (MPA) and binocular depth from motion (DFM). Many cases of early-onset amblyopia and strabismus showed no disparity stereopsis, or position stereopsis, in spite of the presence of DFM. The MPA appeared to be closely related to early-onset esotropia regardless of age, while it disappeared and motion perception became symmetric 4 to 5 months after birth in normal infants. The DFM seemed to play an important role in maintaining good motor alignment for several years after surgery. I developed a checkerboard pattern stimulator in 1978. This method proved to be useful in developing binocular functions and motor alignment by applying simultaneous bifoveolar stimulation and anti-suppression. Extensive exposure to the stimulation was essential for therapeutic success.

Complexes of apoA-1 with phosphatidylcholine suppress dysregulation of arterial tone by oxidized LDL

The aim of this study was to determine whether apolipoprotein A-1 (apoA-1) may suppress the vasomotor dysregulation by oxidized low-density lipoprotein (ox-LDL), which is known to be an atherogenic lipoprotein. The isolated porcine coronary arterial rings and the cultured endothelial cells from the porcine coronary arteries were exposed to ox-LDL in the presence or absence of complexes of apoA-1 with dimyristoylphosphatidylcholine (DMPC/apoA-1), apoA-1 alone, or DMPC alone. DMPC/apoA-1 but not apoA-1 alone or DMPC alone was found to suppress both impairment of endothelium-dependent arterial relaxation and vasocontraction caused by ox-LDL in the isolated porcine coronary arterial rings suspended in organ chambers. DMPC/apoA-1 absorbed lysophosphatidylcholine (LPC) from ox-LDL and decreased the transfer of LPC from ox-LDL to the surface membrane of the cultured endothelial cells, but apoA-1 alone and DMPC alone had no effect. High-density lipoprotein exerted the protective actions mimicking those observed in DMPC/apoA-1. Thus DMPC/apoA-1 decreased the transfer of LPC from ox-LDL to surface membrane by absorbing LPC, leading to the suppression of ox-LDL-induced dysregulation of endothelium-dependent arterial tone. Therefore, apoA-1 appears to require formation of the complexes with phospholipids to prevent the endothelial dysfunction caused by ox-LDL.

Solution structure of an extracellular domain containing the WSxWS motif of the granulocyte colony-stimulating factor receptor and its interaction with ligand

We have determined the NMR structure of a ligand-binding domain of the granulocyte colony-stimulating factor (G-CSF) receptor, containing the highly conserved WSxWS motif. The domain consists of seven beta-strands with the fibronectin type III-like topology seen in several cytokine receptors. Comparisons between the spectra of the 15N-labelled domain with and without G-CSF indicate that the major ligand-recognition site is on the FG loop just upstream of the WSxWS sequence, and not on the BC loop which is mainly used in the growth hormone system. The WSxWS residues are suggested to contribute to ligand-recognition and to the protein architecture of the G-CSF receptor.

Impairment of endothelium-dependent relaxation of rabbit aortas by cigarette smoke extract--role of free radicals and attenuation by captopril

The aim of this study was to examine the effects of the water soluble component of cigarette smoke extract (CSE) on endothelium-dependent relaxation (EDR) of isolated rabbit aortas. The incubation with CSE was found to inhibit EDR in a dose-dependent manner. Co-incubation of the aortic strips with superoxide dismutase (SOD), N-acetylcysteine, glutathione or dimethyl sulfoxide (DMSO), free radical scavengers, attenuated the CSE-induced inhibition of the arterial relaxation. Co-incubation of the strips with captopril (3 mM), an angiotensin converting enzyme inhibitor, also attenuated CSE-induced impairment of vasorelaxation. In parallel experiments using cultured human endothelial cells, CSE suppressed endothelial release of NOx, stable metabolites of nitric oxide (NO). SOD, DMSO and captopril attenuated the suppression of NO production by CSE in association with reduction of free radicals, superoxide anions and hydroxyl radicals, in CSE solution. Neither lactate dehydrogenase release from the cultured endothelial cells nor cell death estimated by trypan blue exclusion test was found after the incubation of the cultured endothelial cells with CSE. The results indicate that free radicals in CSE induce the impairment of EDR, which may be partly due to suppression of NO production and is not due to non-specific cytotoxicity by CSE. Captopril attenuates CSE-induced endothelial dysfunction partly through scavenging free radicals.

The product of the proto-oncogene c-cbl: a negative regulator of the Syk tyrosine kinase

Engagement of antigen and immunoglobulin receptors on hematopoietic cells is directly coupled to activation of nonreceptor protein tyrosine kinases (PTKs) that then phosphorylate critical intracellular substrates. In mast cells stimulated through the FcvarepsilonRI receptor, activation of several PTKs including Syk leads to degranulation and release of such mediators of the allergic response as histamine and serotonin. Regulation of Syk function occurred through interaction with the Cbl protein, itself a PTK substrate in this system. Overexpression of Cbl led to inhibition of Syk and suppression of serotonin release from mast cells, demonstrating its ability to inhibit a nonreceptor tyrosine kinase. Complex adaptor proteins such as Cbl can directly regulate the functions of the proteins they bind.

Study of the effect of atrial contraction on mitral prosthetic valve by high speed video camera

To clarify the effect of atrial contraction on the dynamic behavior of mitral prosthetic valves, a mechanical mock circulatory system has been developed. It is able to simulate the inflow characteristics during diastole. The disc motions of Björk-Shiley Monostrut (BSM29) and CarboMedics (CM29) valves (both with an annulus diameter of 29 mm) were measured and compared with a high speed video camera. After contraction of the artificial atrium (100 ms), there was a delay of 75 ms before the onset of the ventricular contraction. Mitral flow similar to physiological conditions could be achieved. The BSM29 was tested in the anterior position (a) and the posterior position (p). Under the condition of active atrial contraction (AC), we confirmed that the closing motion was initiated and the period during closing motion (PDCM) was prolonged (BSM29[a]: 22.4 +/- 3.4-->63 +/- 3.2; BSM29[p]: 71.2 +/- 38-->94.2 +/- 11; and CM29: 14 +/- 0.0-->28.4 +/- 2.3 [unit: ms]), the prolongation of the PDCM of the CM29 due to the AC being smaller than that of the BSM29. We also confirmed that the closing volume (CV) increased slightly (BSM29 [a]: 7.8 +/- 0.4-->8.5 +/- 0.8; BSM29[p]: 6.9 +/- 0.6-->7.0 +/- 0.5; and CM29: 3.6 +/- 0.6-->4.1 +/- 0.6 [unit: ml]). The CM29 had a shorter PDCM, less prolongation of the PDCM due to the AC, and less CV than the BSM29. Thus, we confirmed that the CM29 produced better response at valve closure than the BSM29.

Radiation dosage reduction in general dental practice using digital intraoral radiographic systems

This report describes the radiation dosage reduction possible in the general dental practice with two CCD (charge-coupled device)-based intraoral radiographic systems: the RVG-S (Trophy Radiologie, Vincennes, France) and the Sens-A-Ray (Regam Medical Systems, Sundsvall, Sweden). Radiation dosages (air-kerma; Gy) necessary for obtaining clinically acceptable images were measured at the cone tip using an ionization chamber type 660-1 (Nuclear Associates, Victoreen, Inc., Carle Place, New York, USA). When the RVG-S was used with an Oramatic 70 (Trophy Radiologie) X-ray generator, dosages at the cone tip ranged from 322 to 612 microGy. These corresponded to 40-60% of the dosages necessary when using Ektaspeed dental X-ray film (Eastman Kodak, Rochester, New York, USA) with a Heliodent 70 (Siemens, Erlangen, Germany) X-ray generator. At 60 kVp, the Sens-A-Ray reduced the dosage in the order of 30% compared with Ektaspeed dental X-ray film. Reduction in radiation dosage is one of the benefits of digital intraoral radiographic systems in general dental clinics. The RVG-S provides greater dose savings than does the Sens-A-Ray.

Cloning, expression and regulation of the human S14 gene

The rat S14 gene has been a useful model to study carbohydrate and triiodothyronine (T3) regulation of hepatic gene expression. To gain insight into the regulation and function of the S14 gene, we isolated the human S14 gene and studied its sequence, tissue specific expression, and transcriptional regulation by glucose and T3. The deduced amino acid sequence of the human S14 protein is 78% identical to that of the rat. Northern blot analysis showed that the S14-mRNA is a single species in human liver and is not present in human brain or HepG2 cells. Transfection studies in primary hepatocytes revealed that transcription of the human S14 gene is regulated by glucose and T3 in a similar manner to that of the rat gene. However, in HepG2 cells, T3 and glucose did not affect the transcription of the human S14 gene. These observations suggest that the S14 gene is highly conserved in mammals and is similarly regulated by carbohydrate and T3 in vivo. More importantly, the function of the human S14 gene may be critical in lipid metabolism in human liver as the rat S14 gene is in rodents.

Effects of ethyl alpha-D-glucoside on skin barrier disruption

Daily treatments of skin in hairless mice with concentrates of rice wine, Japanese traditional alcohol, lowered transepidermal water loss levels compared to the controls on the 3rd day after ultraviolet B (UVB) irradiation. These findings indicate that the concentrates of rice wine suppress the murine skin barrier disruption caused by UVB. Ethyl alpha-D-glucoside (alpha-ethylglucoside), one of the peculiar components in rice wine, showed the same effect, whereas beta-ethylglucoside had no effect. In order to clarify the functions of alpha-ethylglucoside on murine skin, we examined the effects of this compound on the expression of some phenotypes in human keratinocytes in vitro. As a result, alpha-ethylglucoside as well as beta-ethylglucoside enhanced cell proliferation weakly, and the formation of cornified envelopes and differentiated type keratin (K1) in keratinocytes was accelerated by alpha-ethylglucoside but not by beta-ethylglucoside. From the results, we conclude that alpha-ethylglucoside enhanced the differentiation of keratinocytes, which might be related to reduced barrier disruption by UVB.

Host range phenotype induced by mutations in the internal ribosomal entry site of poliovirus RNA

Most poliovirus strains infect only primates. The host range (HR) of poliovirus is thought to be primarily determined by a cell surface molecule that functions as poliovirus receptor (PVR), since it has been shown that transgenic mice are made poliovirus sensitive by introducing the human PVR gene into the genome. The relative levels of neurovirulence of polioviruses tested in these transgenic mice were shown to correlate well with the levels tested in monkeys (H. Horie et al., J. Virol. 68:681-688, 1994). Mutants of the virulent Mahoney strain of poliovirus have been generated by disruption of nucleotides 128 to 134, at stem-loop II within the 5' noncoding region, and four of these mutants multiplicated well in human HeLa cells but poorly in mouse TgSVA cells that had been established from the kidney of the poliovirus-sensitive transgenic mouse. Neurovirulence tests using the two animal models revealed that these mutants were strongly attenuated only in tests with the mouse model and were therefore HR mutants. The virus infection cycle in TgSVA cells was restricted by an internal ribosomal entry site (IRES)-dependent initiation process of translation. Viral protein synthesis and the associated block of cellular protein synthesis were not observed in TgSVA cells infected with three of four HR mutants and was evident at only a low level in the remaining mutant. The mutant RNAs were functional in a cell-free protein synthesis system from HeLa cells but not in those from TgSVA and mouse neuroblastoma NS20Y cells. These results suggest that host factor(s) affecting IRES-dependent translation of poliovirus differ between human and mouse cells and that the mutant IRES constructs detect species differences in such host factor(s). The IRES could potentially be a host range determinant for poliovirus infection.