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Biomedical subjects

K Hashiguchi

Publications and source records attributed to K Hashiguchi.

At least 37 records · Page 2Linked to original sources
PubMed1990

Effect of Nd:YAG laser irradiation on human dental enamel.

The crystallographic alterations of the hydroxyapatite under the laser irradiation were evaluated by the x-ray diffraction pattern analysis and scanning electron microscopic observation. Recrystallization may occur in fused and resolidified dental enamel by the pulsed Nd: YAG laser irradiation. Two different grades of energy densities such as 400 pulses and 800 pulses were given to the powdered enamel. The irradiation was performed at a peak power of 500W with a pulse width of 10 msec.; the average output of 10W, spot size of 3mm and two pulses were given in every second. After the 800 pulses of Nd:YAG laser irradiation to the human dental enamel the x-ray diffraction pattern demonstrated both alpha-tricalcium phosphate and hydroxyapatite peaks. With the lower level of energy at 400 pulses, no significant differences were seen in the diffraction patterns between lased and unlased enamel. In scanning electron microscopic findings, there were no significant changes between lased and unlased enamel. When the unlased and lased enamel were exposed to acid solution, unlased enamel showed a honeycomb pattern, while the lased enamel showed preferentially removed prism core material.

Crystallization↗
PubMed1990

[Detection of herpes simplex virus, varicella zoster virus and cytomegalovirus in aphthous stomatitis].

Attempts were made to demonstrate herpes simplex virus (HSV) type 1 and type 2, varicella zoster virus (VZV) and cytomegalovirus (CMV) in specimens obtained from aphthous ulceration lesions by the immunofluorescent method using fluorescein-labeled monoclonal antibodies. HSV-1 and VZV were detected in 2 and 4 out of 30 patients, respectively. Although almost all viruses that can infect the oral cavity could occasionally cause stomatitis, neither HSV-2 nor CMV was not found in this study. VZV was detected in 1 out of 8 patients with recurrent aphthous ulceration. After treatment with acyclovir, the patient's symptoms has become less severe and recurrence rates of attacks reduced, however, the patient has not been totally free of the disease. There were no differences in clinical aspects of stomatitis between the patients with and without viral isolation. Further clinical investigation is encouraged to confirm the relationship between aphthous stomatitis and viral infection.

Acyclovir↗
PubMed1990

[Supplemental studies on self-curing resins. 2. On polymerizing temperature of reline materials].

The objective of this study was to find the best way to keep down the peak temperature of self-curing reline materials. The experiments were done by using three kinds of self-curing reline materials (Rebaron, REBASE and KOOLiner) and three kinds of the reline materials of different thickness (1.5mm, 2mm and 3mm) under three different intraoral conditions. When these reline materials cured under rinsing the mouth with cold water (18 degrees C), the data analysis of these reline materials showed a considerable reduction in the peak curing temperatures clinical acceptance. The results obtained were as follows: 1. Both extraoral and interoral curing tests showed that the thicker the material is the higher the peak temperature becomes. 2. Highly significant differences in time to the peak temperature were found among the three kinds of reline materials. 3. Dangerously high temperature was found in polymerizing of the thickest material, 3mm.

Denture Liners↗
PubMed1990

[A case of hemoptysis due to administration of an anti-thrombotic drug].

A 63-year-old woman was referred to our division because of massive hemoptysis (200 ml) after administration of ticlopidine, an anti-thrombotic drug, for prevention of recurrent brain infarction. Ticlopidine treatment was stopped on the first hospital day, thereafter the patient's hemoptysis immediately disappeared. A chest roentgenogram and broncho-fiberscopic examination did not reveal any organic lesion associated with hemoptysis. Laboratory data revealed prolonged bleeding time and decreased platelet aggregation, suggesting that the patient had had a hemorrhagic diathesis associated with the administration of ticlopidine. Although many anti-thrombotic drugs have been recently employed in a variety of clinical cases, the patient's hemoptysis was considered to be due to side effects.

Cerebral Infarction↗
PubMed1990

[A case of polycythemia vera associated with idiopathic interstitial pneumonia successfully treated by alkylating agents].

A 62-year-old female was referred to our division because of general fatigue, low grade fever and exertional dyspnea for 2 months. Laboratory data and chest roentgenograms on admission revealed polycythemia vera associated with idiopathic interstitial pneumonia. Alkylating therapy with carboquone and cyclophosphamide resulted in the improvement of abnormalities on chest X-ray films which had previously shown decreased lung fields and abnormal interstitial shadows, as well as hematological abnormalities. Six months later, the results of the patient's pulmonary function tests and arterial blood gas analysis became within normal limits. Little information about polycythemia vera associated with idiopathic interstitial pneumonia is available. This case indicated that alkylating therapy with no steroidal combination is effective for idiopathic interstitial pneumonia.

Alkylating Agents↗
PubMed1989

[Emergency cardiopulmonary bypass for cardiopulmonary-cerebral resuscitation].

Cardiopulmonary bypass (C-P bypass) was performed on two patients who had not responded to conventional cardiopulmonary resuscitation (CPR). The first patient, a 56-y-o male, with bilateral pulmonary thromboembolism repeatedly underwent cardiac massage and electric defibrillation for recurrent ventricular fibrillation. A veno-arterial bypass route was prepared during cardiac massage, and bypass circulation was started 3 hours after the onset of the first ventricular fibrillation. Soon after the initiation of C-P bypass, the physical status and EEG of the patient improved. The patient regained consciousness within a few hours and later underwent open chest pulmonary embolectomy. The second patient, a 44-y-o male, developed refractory cardiogenic shock near the end of aortocoronary bypass graft operation. Under closed chest massage, a femoro-femoral cardiopulmonary bypass operation was started. Soon after the initiation of the bypass circulation and IABP, peripheral circulation improved markedly, and consciousness returned within several hours. Though the first patient finally died from far advanced pulmonary embolism, he was conscious as long as the C-P bypass was continued for two days. In the second patient, the cardiac function gradually improved after the 3rd day. C-P bypass was tapered and discontinued on the 5th day. Emergency veno-arterial bypass for CPR is effective means to maintain life until the cardiopulmonary and cerebral functions are restored. Recent advances in emergency C-P bypass are introduced and a new acronym extracorporeal lung and heart assist, ECLHA, is proposed. Emergency ECLHA with veno-arterial cannulations through percutaneous puncture will become a promising adjunct of cardiopulmonary-cerebral resuscitation in the near future.

Adult↗
PubMed1988

Designed gene amplification on the Bacillus subtilis chromosome.

We previously reported the cloning of a 1.6 kb HindIII fragment (containing the junction of the repeating unit) from chromosomal DNA of Bacillus subtilis strain B7 in which tandem amplification of a 16 kb region occurred, and the induction of B7-type gene amplification by competence transformation with this cloned fragment. Based on this result, we designed, on the B. subtilis chromosome, a gene amplification of the 22 kb repeating unit containing the alpha-amylase structural gene (amyE), the tunicamycin-resistance gene (tmrB) and the shikimate kinase structural gene (aroI). We cloned only two short DNA fragments from both termini of the 22 kb region, constructed a junction structure of the designed repeating unit on pBR327 and transformed a B. subtilis wild-type strain by this constructed plasmid. As a result, we succeeded in obtaining tunicamycin-resistant (Tmr) transformants in which the designed gene amplification of 22 kb occurred on the chromosome. The Tmr transformants showed high productivity of alpha-amylase and shikimate kinase. The copy number of the repeating unit was estimated to be 10-20. This system may provide an effective means of amplifying long (greater than 20 kb) DNA regions on the chromosome.

Amylases↗
PubMed1988

Chlamydia trachomatis: a currently recognized pathogen of tonsillitis.

The authors investigated whether or not Chlamydia trachomatis could be isolated from tonsillar crypts in order to establish directly the relationship of the organism to the tonsillar infection. In 17 of 65 (26.2%) cases with tonsillitis, C. trachomatis was recovered from tonsillar crypts. Ten of the 17 Chlamydia-positive patients were attended for recurrent sore throat and 5 for lingering tonsillitis. Thirteen of the 17 cases had serum antibody to C. trachomatis. We also isolated this microorganism from one of 18 persons complaining of a lumpy throat. Eleven of the 18 Chlamydia-positive patients had pertinent histories of oro-genital sexual activity, and pharyngeal infection apparently resulted from direct inoculation. The available data suggest that tonsillitis, the most common problem in otorhinolaryngology, may be caused by C. trachomatis more often than has been suspected.

Antibodies, Bacterial↗
PubMed1988

A study on the adjuvant activity of palatine tonsil.

The involvement of non-specific factors in the onset of focal infection should never be ignored. We pay attention to the adjuvant activity of tonsil as one of various kinds of nonspecific factors. We confirmed the presence of such substances with adjuvant activity as lipopolysaccharides and muramyl dipeptide in the lacunar debris of tonsil. Then, using experimental animals with adjuvant induced arthritis, the study was made to determine whether the lacunar debris actually exerts adjuvant activity. We demonstrated the presence of adjuvant activity in the lacunar debris.

Adjuvants, Immunologic↗
PubMed1986

Amplification of the amyE-tmrB region on the chromosome in tunicamycin-resistant cells of Bacillus subtilis.

In a class of tunicamycin-resistant mutants (tmrA7) of Bacillus subtilis, the production of extracellular alpha-amylase is increased by about five fold. The tmrA7 characteristics (tunicamycin resistance and hyperproduction of extracellular alpha-amylase) can be transferred to recipient cells by transformation. In the transformants and the original tmrA7 mutant, typical amplification of the region from 4 kb upstream of the amyE gene to the tmrB gene on the chromosome was detected. The repeating unit, 16 kb in size, repeats tandemly about five and ten times in the mutant and transformants, respectively, and the alpha-amylase production is proportional to the copy number of the amyE gene. Simultaneous amplification of the tmrB gene, which is responsible for tunicamycin resistance in the multicopy state, and the alpha-amylase structural gene (amyE) seems to be the cause of the pleiotropy of the tmrA7 mutation.

Bacillus subtilis↗
PubMed1986

Amplification and deletion of the amyE+-tmrB+ gene region in a Bacillus subtilis recombinant-phage genome by the tmrA7 mutation.

A 22.4-kilobase DNA fragment containing the tmrA7-amyR2-amyE+-tmrB+-aroI+ region of the Bacillus subtilis N7 chromosomal DNA was cloned into a recombinant B. subtilis bacteriophage, p11-AA248. The amyE+-tmrB+ gene region, approximately 12.6 kilobases, in the phage genome was amplified in a tunicamycin-resistant (Tmr) Amy+ AroI+ transductant of B. subtilis by p11-AA248. On the other hand, the amyE+-tmrB+ region in the genomes of 80 to 90% of the phage particles was deleted when the phages were induced from the Tmr Amy+ AroI+ transductants by treatment with 1.0 micrograms of mitomycin C per ml. From analyses of the physical maps and DNA nucleotide sequences in the junction region of the deleted phage genome and the parental DNA fragments, it is suggested that the deletion occurred within a direct repeat sequence composed of 18 base pairs. The endpoints of the amplified gene region seemed to be closely related to both terminal regions of the deleted DNA.

Bacillus subtilis↗
PubMed1986

Essential structure in the cloned transforming DNA that induces gene amplification of the Bacillus subtilis amyE-tmrB region.

Bacillus subtilis B7, a mutant which acquired gene amplification of the amyE-tmrB region, showed, as a result, hyperproductivity (about a 5- to 10-fold increase) of alpha-amylase and tunicamycin resistance. The mutational character was transferred to recipient cells by competence transformation. A 14-kilobase (kb) EcoRI chromosomal DNA fragment of strain B7 was found to have the transforming activity. We cloned a 6.4-kb EcoRI fragment on a phage vector lambda Charon 4A through a spontaneous deletion of 7.6 kb from the 14-kb fragment and subcloned a 1.6-kb HindIII fragment on pGR71. The cloned 6.4-kb EcoRI and 1.6-kb HindIII fragments retained the transforming activity of inducing gene amplification of the amyE-tmrB region. At the junction point (J) of the repeating units (16 kb), the tmrB gene was linked to a DNA region (M) located 4 kb upstream of amyE. The essential structure of the cloned, transforming (gene amplification-inducing) DNA was deduced to be that around J. The subcloned 1.6-kb HindIII fragment that retained the transforming activity was shown to be almost solely composed of the tmrB-J-M region. In addition, the DNA sequence around J was determined.

Bacillus subtilis↗