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Biomedical subjects

Y Asai

Publications and source records attributed to Y Asai.

At least 19 recordsLinked to original sources
PubMed1992

A new model of equilibrium dysfunction in the rat induced by photochemical damage to the inner ear's microcirculation.

A new photochemical method was employed to damage the inner ear microcirculation in the rat. Under pentobarbital anesthesia, the middle ear was exposed by a ventral approach and the tympanic membrane and the malleus and incus were removed. The vestibule was then illuminated by a filtered xenon light (wave length: 540 nm) while rose bengal was infused intravenously. Microscopic examination revealed disintegration of the hair cells in the vestibule. Changes could be prevented by pretreatment with intravenous acetylsalicylic acid (ASA) or heparin. Twenty-four hours after the completion of photo-illumination the rats exhibited nystagmus toward the intact ear and showed rolling during the swimming test, both signs of equilibrium dysfunction. These findings were inhibited by ASA or heparin pretreatment. Our present results indicate that our method causes a photochemically induced occlusion in the rat's inner ear microcirculation and may be useful for evaluating the various effects of drugs on the inner ear.

Animals↗
PubMed1992

[A case report of patch aortoplasty for supravalvular aortic stenosis associated with Williams syndrome].

A 15-year-old girl underwent patch aortoplasty for supravalvular aortic stenosis in association with Williams syndrome. Pressure gradient of before and after stenosis of the aorta decreased from 104 mmHg to 16 mmHg at the postoperative catheterization. Angiography after the operation showed no stenosis. Postoperative course was excellent and discharged on 14th postoperative day. The problems of the operation of supravalvular aortic stenosis were discussed.

Adolescent↗
PubMed1992

[Closure of median sternotomy incision with EPTFE sutures].

EPTFE (CV-0) suture was utilized for closure of median sternotomy incision in 100 patients under 6 years of age who underwent open heart surgery. During 3 years follow up, except for one dislocation of sternum, all patients have healed without complication. EPTFE suture is swanged to a needle that has the same diameter as the thread, which reduces bleeding from the needle hole. It is radiologically lucent, and therefore does not disrupt chest X-ray, angiography or MRI investigations, in contrast to sternal wires. In addition, in the case of life threatening postoperative complication, EPTFE suture allows rapid and simple access to the heart, without the need to cut wires. We concluded that EPTFE suture can be utilized for closure of median sternotomy in patients under the age of six, without an increased risk of postoperative or long-term complications.

Child, Preschool↗
PubMed1991

Clinico-pathological studies on the tissue reactions of human pulp treated with various kinds of calcium phosphate ceramics.

The aim of this study was to evaluate the clinical values of calcium phosphate ceramics from the biological point of view. Two kinds of calcium phosphate ceramics, tricalcium phosphate (TCP) and hydroxyapatite (HAP) ceramics with a low sintering temperature (LT) and a high sintering temperature (HT), were applied to exposed pulp wounds in ninety healthy human teeth. Each group was further subdivided into 2 groups with selected granule diameters of 5 microns (S) and 40 microns (L), and investigated clinico-pathologically. Clinically, cases showing some kinds of discomfort symptoms comprised 3/15 of the TCP (S) group, 3/15 of the TCP(L) group, 3/15 of the LT(S) group, 4/15 of the LT(L) group, 2/15 of the HT(S) group, and 3/15 of the HT(L) group. The symptoms were generally slight or very slight and disappeared within eight days in the LT(S) group. Histo-pathologically, inflammatory reactions were observed within 2 weeks. Traumatic injury caused by surgical wound or by mechanical irritation from the materials produced various pathological changes. After the treatment, pulp manifested reparative changes such as cicatrization, formation of new denticles, and dentin apposition on pulp-chamber walls. In many cases, TCP and HAP produced similar effects on human dental pulp. In the TCP(S), the LT(S), and HT(S) groups, a calcified matrix had appended by 3 weeks. In TCP(L), LT(L), and HT(L) groups, the matrix had appended from 3 to 6 weeks. Calcified matrix formation in the LT group was slightly less than in that in the HT of HAP group. In a few cases, complete dentin bridges formed over the exposed pulp surfaces. These results suggest that HAP (both LT and HT) and TCP ceramics are biocompatible and do not harm human dental pulp. These ceramics were found to be clinicopathologically effective in biologically protecting exposed human dental pulp and useful as basic materials in endodontic therapy.

Adolescent↗
PubMed1991

[Experience of extracorporeal shock-wave lithotripsy for the urolithiasis in horseshoe kidney].

At Osaka City University, 1,987 patients with urolithiasis have been treated by extra-corporeal shockwave lithotripsy (ESWL) during a four-year period. We treated 5 patients with horseshoe kidney and the obtained results were analyzed retrospectively. Three of these patients, who had a solitary stone could successfully be treated by ESWL as monotherapy. One who had multiple stones required transurethral lithotripsy after ESWL due to stone-street. The remaining 1 patient who had undergone heminephrectomy developed perirenal hematoma after ESWL, which spontaneously disappeared without any specific treatment. We discuss the special care related to the use of ESWL in the horseshoe kidney.

Adult↗
PubMed1991

[Surgical treatment of pulmonary atresia with intact ventricular septum in infancy--analysis of right ventricular growth potential after pulmonary valvotomy].

Our surgical experience involving pulmonary atresia with intact ventricular septum (PPA) between the years 1981 and 1989 is reviewed. Twelve infants aged 3 days to 11 months were studied for right ventricular growth potential with angiocardiography and hemodynamics after transventricular pulmonary valvotomy (TVPV). Ten infants were divided into two groups, 5 infants (Group I) were treated with TVPV only, and the other 5 infants (Group II) required additional surgery after the initial operation (TVPV in 2 cases and TVPV with shunt in 3 cases). Post-operative RV growth potential was evaluated with right ventricular index (RVI) based on the tricuspid valve annulus, right ventricular inlet, and right ventricular outlet dimensions, and with tricuspid annular index (TVI) based on the tricuspid valve annulus normalized by aortic diameter. Follow-up (3-69 months after initial operation) studies demonstrated that the RV cavity increased in Group I (RVI of 15.75 +/- 2.92 preoperatively versus 17.00 +/- 1.57 postoperatively, TVI of 3.04 +/- 0.63 versus 3.85 +/- 0.40). In contrast, the RV cavity in Group II demonstrated a lack of growth (RVI of 9.24 +/- 2.60 versus 9.85 +/- 2.76, TVI of 1.46 +/- 0.46 versus 1.70 +/- 0.80). PPA infants with RVI greater than 11 have been treated successfully with TVPV alone, which may maximize the potential for RV growth, but infants with RVI less than 11 have not experienced RV growth + postoperatively and, therefore, have required second intracardiac operations.

Angiocardiography↗
PubMed1990

[Histopathological studies of periodontal tissue reactions following apical plugging with autogenous dentin chips].

After treating the infected canals, we investigated to determine the influence of autogenous dentin chips accidentally applied as filling in the root apexes. Materials were 15 mandibular premolars and molars obtained from healthy, mature dogs. According to standard procedures, after pulp extirpation, canals were temporarily filled with sandarac cotton pellets and left otherwise untreated for 4 weeks. At this time, the degree of infection was ascertained. After root-canal enlargement, root canals were filled with No. 55 gutta-percha points; and a sealer (Neotriozinc Paste, AH26, or Sealapex) was applied. The animals were sacrificed at the conclusion of either a short term (2 weeks) or a long term (16 weeks), and histological studies were performed. Conclusions In short-term specimens, no formation of new hard tissue was observed at the apical dentino-cemental junction; and inflammatory changes in the periapical soft tissue were remarkable. In long-term specimens, hard-tissue formation had resulted in apical closure in 6 out of 8 instances; and periapical inflammatory changes had decreased. Relations between dentin-chip density and histopathological conditions were as follows: In most of the specimens that were evaluated as good, dentin chips were very densely applied. Insufficient numbers of dentin chips produced poor results. In other words, dense applications of dentin chips result in good prognoses. Consequently, when root-canal enlargement has been adequately performed, application of dentin chips to the apex of infected canals stimulates hard-tissue formation resulting in biological apical closure. In infected canals, however, the degree to which dentin chips are infected can be a major factor.

Animals↗
PubMed1990

[Consideration of management of type B dissecting aneurysms of the thoracic aorta: clinical comparative study between surgical and medical treatments].

Between 1970 and 1989, 116 patients with type B dissecting aneurysms of the thoracic aorta were seen in our institution and affiliated hospitals. The patients were classified into 5 groups according to the acuity (acute vs chronic) and modes of therapy (surgical vs medical). Group I: 24 patients with acute B dissection were treated surgically during the acute stage. Group II: 21 patients with acute B dissection were initially treated with intensive medical therapy and followed by elective operation during the subacute stage. Group III: 22 patients with acute B dissection were treated medically. Group IV: 42 patients with chronic dissection were treated surgically. Group V: 7 patients with chronic B dissection were treated medically. The 5-year survival rates including early mortality were 70.5 +/- 9.4% for Group I, 88.9 +/- 7.5% for Group II, 68.3 +/- 11.2% for Group III, 64.6 +/- 8.4% for Group IV and 71.4 +/- 17.1% for Group V. The 5-year survival rates of Group II was significantly better than those of Group I, III and IV, respectively. The present data suggests that acute type B dissection without complications (bleeding, visceral or lower limbs ischemia) should be treated initially with intensive medical therapy and then followed by elective operation during the subacute stage, if the false lumen were not thrombosed.

Adult↗
PubMed1989

[The c protein fractions of group B streptococci: its distribution and relation to heat-labile antigens for the agglutination method].

Distribution of the c protein fractions of group B streptococci and relation to heat-labile antigens for agglutination were investigated. The results were summarized as follows: 1. Analysis of antigenicity of the c protein in group B streptococcal strains isolated revealed that 74% of the type Ia/c strains carried only alpha antigen, and 76% of the type Ib/c strains contained both alpha and beta antigens. Component of the c protein fractions in most of type Ia/c strains isolated was different from that in reference strains. 2. Of 37 Ia/c alpha strains, 45.9% were determined non-typable, 32.4% were Ia/W, 13.5% were Ia/S, and 8.1% were Ia/Q in the agglutination for heat-labile antigens. Of 8 Ia/c alpha beta strains, 87.5% were Ia/Q, and 12.5% were Ia/SW. Of 5 Ia/c beta strains, 60% were Ia/Q, and 40% were Ia/QW. Of 19 Ib/c alpha beta strains, 68.4% were Ib/-, and 31.6% were Ib/S. Of 5 Ib/c alpha strains, 60% were Ib/-, and 40% were Ib/S. One Ib/c beta strain was Ib/-. 3. Because trypsin-sensitive portions of the beta antigens were lost, preparation of antigens for agglutination by pancreatic digestion could not exactly reflect results of the precipitation method.

Agglutination Tests↗
PubMed1989

In vivo binding of circulating immune complexes by C3b receptors (CR1) of transfused erythrocytes.

The effects of packed erythrocyte transfusion with high CR1 activity on circulating immune complex concentrations were studied in 14 transfusion experiments involving 12 patients with immune complex related diseases. Before erythrocyte transfusion circulating immune complex concentrations ranged from 8 to 128 micrograms/ml. After transfusion (2-3 units) immune complex concentrations decreased depending on the levels of CH50 titres in the recipients. In 11 experiments, in which the patients' CH50 titres ranged from 21 to 44, immune complex concentrations decreased by 75-100% within five days. The CH50 titres were also decreased after erythrocyte transfusion but subsequently increased to initial ranges within 6-35 days. In three patients with low CH50 titres (1.0-10.0) decreases in immune complexes were not observed. Direct Coombs' tests for IgG and C3 were performed before and after erythrocyte transfusion to determine potential in vivo binding of circulating immune complexes. Thus in eight of 14 experiments, in which erythrocytes carried no IgG before packed erythrocyte transfusion, seven became Coombs' positive for IgG after the transfusion. In seven of 14 experiments, in which erythrocytes were negative for complement before transfusion, five became positive afterwards. Moreover, in 12 instances slight increases of CR1 activity of patients' erythrocytes were observed within eight days, which improved further within 35 days after erythrocyte transfusion. These studies suggest that transfusion of erythrocytes with high CR1 activity results in the removal of circulating immune complexes and that this process is dependent on complement consumption. These experiments support the hypothesis that erythrocyte-CR1 has a functional role in the removal of circulating immune complexes and may thereby inhibit the deposition of immune complexes within body tissue constituents.

Antigen-Antibody Complex↗
PubMed1989

Diagnosis of arteriosclerosis obliterans by impedance technique with special reference to relative blood flow of the lower extremity.

Simultaneous recordings of impedance cardiography of the chest and impedance plethysmography of the lower extremity were performed on 105 limbs with or without arteriosclerosis obliterans (ASO) documented by angiography. The ratios of blood flow to the lower extremity--leg stroke volume/cardiac stroke volume--(LSV/CSV) were 11.2 +/- 3.3% in normal male subjects, 11.1 +/- 5.5% in normal female subjects, and 3.1 +/- 1.2% in lower extremities with ASO, respectively. The normal value (range) for LSV/CSV calculated from the normal groups by the percentile method was between 4.9% and 17.8%, and the diagnostic accuracy of this value was 100% for sensitivity and 97.5% for specificity. LSV/CSV is a good index for the diagnosis of ASO and makes it possible to minimize error when expressed as an absolute value.

Arteriosclerosis Obliterans↗
PubMed1989

[Effectiveness of the bidirectional Glenn shunt for the univentricular heart].

Two cases underwent a modified Fontan operation with simultaneous superior vena cava-right pulmonary artery end-to-side anastomosis, which we called "bidirectional Glenn shunt". This anastomosis seems to be so effective for reduction of right arterial volume loading, and could proved life-saving in the case with the acute obstruction at the site of the right atriopulmonary artery anastomosis immediately after surgery.

Anastomosis, Surgical↗
PubMed1989

[Modified Fontan operation of single ventricle with D-TGA].

An 8-year-old boy who had previously received two systemic pulmonary shunts, underwent successfully direct anastomosis between SVC and right pulmonary artery (bidirectional Glenn shunt), and proximal side of SVC and main pulmonary artery. Post operative course was uneventful with pleural effusion during a shot period. Post operative right atrial pressure was 9/5 mmHg without evidence of live swelling.

Anastomosis, Surgical↗
PubMed1989

[Histopathological studies of periodontal tissue reactions to perforations in the furcation of dogs' teeth treated with cyanoacrylate cement (FH Cement)].

In the previous study (Shikwa Gakuho, 85: 413-451, 1985.), Morinaga reported on the histopathology of furcation perforations treated with ethyl cyanoacrylate and showed that, because of its properties, this material cannot be expected to effect a permanent blockade. It did not, however, irritate the wound. The purpose of this study is to investigate the effects of a new cyanoacrylate cement (FH Cement) when applied to furcation perforations. Subjects were 25 mandibular and maxilla premolars and molars obtained from 3 adult dogs. The method used in the study was as follows. After administration of pentobarbital-sodium general anesthesia, the pulp chamber was opened by means of a high-speed air turbine fitted with a diamond point. According to usual procedures, the pulp was removed, and the main root canal was filled. Next the floor of the pulp chamber was deliberately perforated by means of a 1mm round bur that had been previously sterilized in advance pouring a physiological sodium chloride solution at the same time. The perforated areas were then washed with a same solution, wiped, and dried with aseptic cotton pellets. They were then stuffed with cyanoacrylate cement. The cavity was lined with gutta-percha temporary stopping, and the remainder of the cavity was filled with silver amalgam. At periods of 1, 2, 4, 8 and 12 weeks after the operation, the animals were sacrificed by means of electricity under general anesthesia. The jaw bones were removed, fixed, decalcified, and embedded in celloidin. Longitudinal sections were stained with hematoxylin-eosin. Results 1. Periodontal tissues around perforated sites were healed by means of scar tissue, though suppuration occurred in a few cases. 2. Hard tissue was appended to the teeth in a small number of cases. 3. Repair of the alveolar bone was observed in the damaged site in about half of all cases. From the result mentioned above, cyanoacrylate cement (FH Cement) was seemed to did not close the site perforation for it self, but was not a stimulant to wound, in case of appropriate blockade.

Animals↗
PubMed1989

Ultrastructure of initial calcification on exposed human pulp applied with autogenous dentin fragments.

Initial calcification in human dental pulp has been studied with electron microscopy in 20 human teeth over a period of 21 days following pulp exposure and capping with autogenous dentin fragments. Five days after operation, dentin fragments were surrounded by degeneration cells and inflammatory cells. Occasionally a macrophage that had phagocytosed a dentin fragments was observed. Fourteen days after operation, osmiophilic needle-like crystalline structures were found in spherical bodies in the collagen fibrils or on the dentin surface. Ca and P were detected in these needle-like crystalline structures by energy dispersive X-ray analysis. They tended to increase in size and to fuse together to form mineralizing globules with the passage of time. Initial calcification around the dentin fragments developed various patterns, including spherical bodies in the collagen fibrils and direct apposition of needle-like crystals on the dentin fragments.

Adolescent↗