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Biomedical subjects

K Aoyama

Publications and source records attributed to K Aoyama.

At least 91 records · Page 5Linked to original sources
PubMed1996

[Effects of shock experience on aversiveness caused by the scream of other rats: overshadowing tests of the association assumption].

Distress responses of rats like screams are aversive for other rats. This study was conducted to determine some of the conditions affecting these aversive properties. Eighteen rats were trained to press a lever to obtain food on a FR4 schedule, then assigned to Shock-experienced group (SE). Overshadow group (OS), and Control group (CNT). SE received three 1-second shocks (1 mA) a day for two days in a grid-floor box. The procedure for OS was the same as that for SE except that a 40-W lamp was lit 30 seconds before the onset of the shock. CNT received neither lights nor shocks. During the next eight days, rats received FR4 schedule with the same procedure as for training except that lights (40 W) or screams (65 dB) were presented for 1 minute. When lights were presented, OS showed marked response suppression but SE and CNT showed little one. When screams were presented, SE revealed strong suppression although CNT and OS showed weak one. These results indicate that aversion to screams was determined by Pavlovian conditioning.

Animals↗
PubMed1995

The triple airway manoeuvre for insertion of the laryngeal mask airway in paralyzed patients.

The efficacy of the triple airway manoeuvre (mouth opening, head extension and jaw thrust) for insertion of the laryngeal mask airway (LMA) was compared with the standard insertion method. One hundred paralyzed patients were allocated randomly into two groups: in the control group (n = 50) the LMA was inserted by the standard method, and in the other (TAM group, n = 50) by the triple airway manoeuvre. In ten patients of each group, the position of the LMA and the epiglottis was assessed radiographically before insertion, after insertion but before cuff inflation, and after cuff inflation. In all patients the position was examined using fibrescopy before and after cuff inflation. The mean distance between the epiglottis and the posterior pharyngeal wall, measured radiographically before LMA insertion, was greater in the TAM group (16.3 (SD 4.3) mm) than in the control group (7.0 (2.8) mm) (P < 0.001). Before cuff inflation, radiography and fibrescopy showed that the LMA compressed the epiglottis downwards more frequently in the control group. After cuff inflation the glottis was completely visible fibreoptically in 66% in the TAM group, compared with 14% in the control group (P < 0.001). Complete downfolding of the epiglottis was seen in 10% in the control group and none in the TAM group (P < 0.05). We conclude that in paralyzed patients LMA insertion with the triple airway manoeuvre provides wider pharyngeal space and decreases the incidence of epiglottic downfolding by the LMA compared with the standard method.

Adult↗
PubMed1995

A method for 2D crystallization of soluble proteins at liquid-liquid interface.

Two-dimensional crystals of soluble proteins were formed at the interface between an aqueous solution of proteins and a thin organic liquid (dehydroabietylamine). Proteins were adsorbed to the interface from the aqueous side and formed a two-dimensional crystal under suitable conditions. This method offers the advantage of great surface mobility and ideal homogeneity. Furthermore, the positive charge attracted negatively charged proteins well to the interface and no denaturation of the proteins was observed. With this technique, two-dimensional crystals of ferritin, catalase, chaperonin and 50S ribosome were prepared and their structural features were determined.

Abietanes↗
PubMed1995

The precore/core promoter mutant (T1762A1764) of hepatitis B virus: clinical significance and an easy method for detection.

Recently, a new hepatitis B virus (HBV) mutant with HBe antigen-negative phenotype has been characterized, in which one TATA box-like motif of the precore/core promoter had degenerated: most frequently by both A-->T and G-->A mutations at positions 1762 and 1764, respectively. The clinical significance of this mutant is as yet unknown. In our present study, the T1762 A1764 mutant was sought in sera from HBV-infected blood donors and chronic liver disease patients by directly sequencing a PCR-amplified region of HBVDNA. Also, because the A1764 mutation generates a Sau3AI cleavage site (GGTC-->GATC), we digested the PCR products with Sau3AI to see if cleavage would occur at this specific site. Our results mostly corroborated the earlier report but we found a higher-than-predicted frequency of HBe antigen-positive blood donors positive for the mutant (22%). The titres of HBe antigen in these mutant-positive sera were slightly decreased compared to the titres in wild-type HBV infection. In addition, these blood donors had relatively high (though within the normal range) serum alanine aminotransferase (ALT) levels, suggesting that the T1762 A1764 mutation could be used as a sensitive laboratory marker for insidious hepatitis in these otherwise 'asymptomatic' carriers. The Sau3AI assay, which is much more convenient than sequencing, was shown to be useful for the detection of the T1762 A1764 mutant in an extensive number of clinical samples.

Alanine Transaminase↗
PubMed1995

[A case of a synchronous triple primary lung cancer with hamartoma].

We present a case of synchronous triple primary lung cancer. 69-year-old male admitted after mass examination with the tumor shadows on right S3, left S4 and left S8. Further examinations confirmed as squamous cell carcinoma of right S3 and left S8 and as benign tumor of left S4 with right hillar lymph nodal swelling. In addition to these lesion, bronchofiberscopy revealed the squamous cell carcinoma of left basal bronchus. The secondlook operation was planned for bilateral primary lung cancer. At first, patient underwent right S3 segmentectomy with regional lymph nodes dissection. Two month later, left thoractomy was performed, followed by left lower lobectomy. Histopathological examination defined as well differentiated squamous cell carcinoma, moderately differentiated squamous cell carcinoma, squamous cell carcinoma in situ and hamartoma for right S3, left S8, left basal bronchus and left S4, respectively. Lymph node metastasis was found only in #121. Although tumors were resected with good curability, respiratory function was depressed and performance status deteriorated. It is important to attention to the preservation of respiratory function for the surgical treatment to multiple lesions and the combined therapy with radiation, chemotherapy and/or laser may be considered.

Aged↗
PubMed1995

[Familial sacrococcygeal teratoma].

Familial sacrococcygeal teratomas are very rare. Up to now, only 8 kindreds (31 patients, including 1 Japanese kindreds) have been reported. All cases are Altman type IV variety. The tumor complex consists of a presacral teratoma and sacrococcygeal bony anomalies. The most common symptoms are constipation and anorectal stenosis. Two patients died. One died of meningitis following removal of a large benign tumor because of communication with a spinal arachinoid space. The other, with a large benign tumor, died as a result of malignant change, 10 years later after the first operation. The incidence of malignant change of familiar sacrococcygeal teratoma is rare in comparison with that of non-familiar sacrococcygeal teratomas.

Age Factors↗
PubMed1994

Provocation of respiratory allergy in guinea pigs following inhalation of free toluene diisocyanate.

An animal exposure experiment which simulated a workplace exposure situation was made to compare toluene diisocyanate (TDI) concentrations which resulted in antibody production with those which elicited pulmonary responses. Groups of guinea pigs were exposed to inhaled TDI from 0.02 to 1.0 ppm (micrograms/g) for 3 h/day on 5 consecutive days. Three weeks later the animals were challenged with 0.02 ppm of free TDI for 15 min. TDI specific antibodies and pulmonary responses were evaluated. Specific antibody production showed a linear correlation to TDI concentration at induction. Most of the animals exposed to TDI levels above 0.2 ppm displayed significant pulmonary responses, but no correlation was found between TDI concentration at induction and the intensity of pulmonary response upon challenge to free TDI. These results indicated that there was a threshold concentration of 0.02 ppm TDI for antibody production and for the development of pulmonary response. It was also found that exposure to TDI at a level lower than its threshold concentration for sensitization may elicit a response in previously sensitized individuals.

Air Pollutants, Occupational↗
PubMed1994

Evidence for effect of random genetic drift on G+C content after lateral transfer of fucose pathway genes to Escherichia coli K-12.

The cps cluster of Escherichia coli K-12 comprises genes involved in synthesis of capsular polysaccharide colanic acid. Part of the E. coli K-12 cps region has been cloned and sequenced and compared to its Salmonella enterica LT2 counterpart. The cps genes from the two organisms are homologous; in the case of the LT2 genes, with G+C content of 0.61 and codons characteristic of high G+C species, it seems clear that they have been acquired relatively recently by lateral transfer from a high G+C species. The K-12 form of these cps genes is closely related to those of LT2 so must derive from the same high G+C species, but it appears to have transferred much earlier such that random genetic drift has brought P3 (the corrected G+C content of codon base 3) down from 0.77 to 0.64, more than halfway to the E. coli average of 0.57. We estimate, using an equation developed by Sueoka, that the lateral transfer to E. coli took place approximately 45 million years ago. This is the first report we are aware of demonstrating the expected adjustment of P3 after lateral transfer between species with different G+C content DNA.

Amino Acid Sequence↗
PubMed1994

Delayed-type allergenicity of triforine (Saprol).

The delayed-type allergenicity of triforine (Saprol), 1,4-bis (2,2,2-trichloro-1-formamidoethyl) piperazine, was studied. In a mass examination of chrysanthemum growers among whom triforine was commonly used, the highest rate of positive patch test reaction was seen to triforine (17%) among the 7 pesticides and chrysanthemum extracts tested. A higher prevalence rate of work-related skin symptoms was seen in subjects with a positive patch test reaction to triforine (44%) than in those with negative reactions to all allergens tested (15%) (p < 0.05). 12 subjects (67%) with positive patch test reactions to triforine were also positive to dichlorvos (DDVP), with a high kappa coefficient (0.65). The grading of guinea pig maximization test to triforine was grade IV (66%), defined as "strong". Cross-sensitization between triforine and dichlorvos was also shown. The present results confirm that triforine is capable of including delayed-type allergy among chrysanthemum growers and of showing cross-reactivity with dichlorvos.

Adult↗
PubMed1994

[The influence of conspecific distress responses on the lever choice behavior in the rat].

We examined whether distress responses of rats would be a negative reinforcer or not. In Experiment 1, two rats were placed in adjacent compartments. One rat was reinforced by a food pellet for pressing either of two levers. One of the levers produced food while the other produced food plus electric shock (0.5-2.0 mA) to the other rat. All rats preferred the former lever. In addition, this tendency was more prominent in rats that had experienced shock previously than those without experience. In Experiment 2, one lever produced food while the other produced food plus auditory stimuli, a recorded distress scream (65 dB) or a pure tone (3 kHz, 65 dB). Rats that chose between food and food plus another rat's scream avoided being exposed to the scream. Rats that chose between food and food plus the pure tone chose the two levers equally. These results suggest that negative emotional responses of the conspecifics could be a negative reinforcer.

Acoustic Stimulation↗
PubMed1994

Electron holographic observation of thin biological filaments.

A non-staining bacterial flagellum filament only 24 nm in diameter has been observed clearly by using a phase-shifting electron holographic technique. This method produces a sufficiently high contrast in-focus image that could never be obtained by ordinary transmission electron microscopic (TEM) methods.

Flagella↗
PubMed1994

[Localized cardiac tamponade after aortic valve replacement: a case report].

We report a case of localized cardiac tamponade after aortic valve replacement. A 56-year-old man had an aortic valve replacement for his aortic valve steno-insufficiency. At 3-postoperative day, severe hypotension occurred, causing acute renal failure. There were no cardiomegaly, high central venous pressure, nor echo-free space. A mass shadow, appearing on chest X-ray at 37-postoperative day, was diagnosed as a localized tamponade by means of a computed tomography and a radioangiography at 38 postoperative day. After the spontaneous drainage of old bloody effusion from the partially opened wound in mid-line, his cardiac and renal failure improved rapidly. When the hematoma is localized, computed tomography is most diagnostic while conventional echo-cardiography often fails to show echo-free spaces.

Aortic Valve↗
PubMed1993

Separation of different molecular forms of mouse IgA and IgM monoclonal antibodies by high-performance liquid chromatography on spherical hydroxyapatite beads.

High-performance liquid chromatography (HPLC) on newly developed spherical beads of hydroxyapatite (HAP) was applied to the separation of different molecular forms of mouse IgA and IgM monoclonal antibodies (mAbs). Monomeric, dimeric, trimeric and tetrameric forms of an IgA mAb were eluted from the column separately with appreciable differences in retention volume by a 20 ml (40 min) gradient of phosphate buffer (pH 6.8) of concentration from 10 to 400 mM. The volumes of respective forms were highly reproducible. In addition, a monomeric form was resolved successfully from a pentameric form of IgM mAbs by HPLC on HAP beads under the same conditions. All forms of IgA and IgM mAbs were eluted almost quantitatively from the column. The results indicate that HPLC on HAP beads is useful for isolation and characterization of different molecular forms of IgA and IgM mAbs.

Animals↗
PubMed1993

Immediate-type allergy related to okra (Hibiscus esculentus Linn) picking and packing.

Two workers (cases A and B) engaged in picking and packing okra who had complaints of work-related allergic symptoms showed distinct positive intradermal reactions to two brands of okra extracts only with thresholds of 1 x 10(-8) w/v for Case A and 1 x 10(-6) w/v for Case B. Both also showed positive reactions to okra extracts in the Prausnitz-Küstner test and in the provocative nasal test. The radioallergosorbent test scores to the okra extract were determined to be 2 (defined as clear positive) for Case A and 1 (border line) for Case B. These findings indicated that the allergic conditions of these cases were from an IgE-mediated immediate-type allergy induced by handling okra. To confirm the etiology of the two cases 14 farmers engaged in picking and packing okra were examined. Among them, 8 subjects (57%) showed positive intradermal reactions to okra extracts. A close association between intradermal reactions to okra extracts and complaints of work-related allergic symptoms was seen in these subjects. These results confirm that the okra may be capable of inducing IgE-mediated immediate-type allergy to workers handling okra.

Adult↗
PubMed1993

Experimental study on respiratory sensitivity to inhaled toluene diisocyanate.

Groups of guinea pigs were exposed via inhalation to toluene diisocyanate (TDI) ranging from 0.02 to 1.0 ppm for 3 h/day on 5 consecutive days. Three weeks later, guinea pigs were challenged with TDI-GSA conjugates. Evaluations were based on TDI specific antibodies, pulmonary response and antigen stimulated histamine release from lung mast cells (LMC). The results indicated that both the antibody titer and the severity of pulmonary response followed a concentration-dependent pattern, with corresponding threshold levels. Antibodies and pulmonary responses were undetectable in animals exposed to 0.02 ppm TDI; however, exposure to 0.2 ppm TDI resulted in significant antibody production and pulmonary responses. Animals showed higher antibody titers and more severe pulmonary responses as TDI concentration increased from 0.6 ppm to 1.0 ppm. A discrepancy which was noted between antibody production and pulmonary responses was thought to be relevant to the discrimination of the potentials of antigen stimulated histamine release from LMC mediating between these two responses.

Administration, Inhalation↗