PubMed Health⌕ Search

Biomedical subjects

S Kitamura

Publications and source records attributed to S Kitamura.

At least 73 records · Page 4Linked to original sources
PubMed2001

Applications of fluorescence microscopy to studies of dental hard tissue.

In this review we describe applications of fluorescence microscopy to investigations of dental hard tissue. Many studies have shown that human teeth show autofluorescence and several applications of fluorescence microscopy have been reported, although the chemical nature of autofluorescence remains unknown. However, most applications are based on a static measurement mode, which has inherent limitations. These limitations can be overcome by the use of time-resolved fluorescence microscopy. Therefore, we attempted to combine ordinary and time-resolved fluorescence microscopy to study human dentine. Using stationary measurements, blue fluorescence with a peak of 440 +/- 10 nm and a width of approximately 100 nm was observed. Increases in fluorescence intensity were found to be dependent upon age and temperature, regardless of tooth type or gender. The results suggest that the aging mechanism for crown dentine differs from that for root dentine and that the observed increase in fluorescence intensity is partially due to a temperature-dependent physicochemical mechanism. We speculate that fluorescence microscopy will become a useful tool for analysis of dental hard tissue in several fields.

Aging↗
PubMed2001

Extremely high drug-reductase activity based on aldehyde oxidase in monkey liver.

Drug-reducing ability of monkey liver cytosol was examined in this study. Monkey liver cytosol exhibited significant reductase activities toward zonisamide, sulindac and imipramine N-oxide in the presence of 2-hydroxypyrimidine or benzaldehyde, an electron donor to aldehyde oxidase. These activities were abolished by inhibitors of aldehyde oxidase, such as menadione. These reductase activities in monkeys were extremely high compared to those in other animals. The zonisamide reductase activity of monkey liver cytosol was about 40-fold higher than that of the liver microsomes. It appears that the high levels of aldehyde oxidase exists in monkey liver, and zonisamide, sulindac and imipramine N-oxide are mainly reduced by this enzyme, not by cytochrome P450.

Aldehyde Oxidase↗
PubMed2001

Novel non-peptide GPIIb/IIIa antagonists: synthesis and biological activities of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2-oxoethyl)-2-oxopiperazinyl] acetic acids.

To improve the in vitro and in vivo potency of our first low molecular weight GPIIb/IIIa antagonist 1 (TAK-029), a series of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2-oxoethyl)-2-oxopiper-azinyllacetic acids were synthesized through modification of the glycine moiety of 1 and evaluated for their ability to inhibit in vitro adenosine 5'-diphosphate (ADP)-induced platelet aggregation of guinea pig platelet rich plasma (PRP). Among the compounds examined, the (3S,2S)-4-methoxyphenylalanine derivative 4h showed the most potent antagonistic activity with an IC50 value of 13 nM. Dose-dependent inhibition of ex vivo platelet aggregation was achieved with oral administration of 4h (0.3-1.0 mg/kg) to guinea pigs. Complete inhibition was observed for up to 8 h, and 43% inhibition could still be observed 24 h after oral administration of 1.0 mg/kg. The long-lasting antiplatelet effect of 4h suggests that 4h would be suitable for once-a-day dosing. Structure-activity relationships (SAR) were examined in the series of the phenylalanine derivatives. An increase in the electron density around the 4-position of the phenyl ring of the phenylalanine moiety led to an increase in the antiplatelet activity, suggesting the existence of a hydrophobic and electrostatic interaction site in addition to the ionic binding sites in the GPIIb/IIIa.

Acetates↗
PubMed2001

Orally active GPIIb/IIIa antagonists: synthesis and biological activities of masked amidines as prodrugs of 2-[(3S)-4.

To improve the in vivo potency of the potent GPIIb/IIIa antagonist 2-[(3S)-4-[(2S)-2-(4-amidinobenzoylamino)-3-(4-methoxyphenyl)propanoyl]-3-(2-methoxy-2-oxoethyl)-2-oxopiperazinyljacetic acid (4), the amidino group was converted to an oxadiazole ring, thiadiazole ring or substituted amidoxime group. These groups were expected to be metabolized to an amidino group in vivo. The compounds synthesized were evaluated for their potency to inhibit the ex vivo adenosine 5'-diphosphate (ADP)-induced aggregation of guinea pig platelets. Among the compounds examined, the methoxycarbonyloxyamidine 8a exhibited the most potent ex vivo inhibitory activity with a fast onset and prolonged duration of action after oral administration.

Acetates↗
PubMed2001

A case report of spondyloepiphyseal dysplasia congenita.

Spondyloepiphyseal dysplasia congenita (SED) is a rare form of skeletal systemic disease, characterized by congenital dwarfism with a short trunk and epiphysial dysplasia in the long bones and vertebral bodies. Patients also frequently suffer from atlanto-axial instability due to os odontoideum. Compression of the spinal cord caused by atlanto-axial instability is a common, serious complication in SED patients, and causes severe spinal cord symptoms or occasionally sudden death. We present an SED patient who underwent a posterior fusion of the occiput to the cervical spine for severe spinal cord symptoms due to atlanto-axial instability.

Atlanto-Axial Joint↗
PubMed2001

Fulminant pneumonia due to Aeromonas hydrophila in a man with chronic renal failure and liver cirrhosis.

A 40-year-old man on hemodialysis was admitted due to dyspnea and chest pain and was diagnosed with pneumonia and pericarditis. Ampicillin was administered, but thereafter severe septic shock developed. The fulminant type of pneumonia progressed rapidly, and he died only 48 hours after the onset of symptoms. The autopsy and sputa culture revealed pneumonia due to Aeromonas hydrophila. The source of this infection remained unkown. Interestingly, there were two types of A. hydrophila found during such a short period. The physician should suspect this disease by questioning the patient's history. Early treatment with adequate antibiotics is the only means of saving such a patient's life.

Adult↗
PubMed2001

Long-term pathological changes of expanded polytetrafluoroethylene (ePTFE) suture in the human heart.

Expanded PTFE (ePTFE) sutures have been used widely as a mitral chordal substitute. We present a structural analysis of ePTFE sutures implanted as artificial chordae for 7.5 years and 8.6 years in patients with mitral regurgitation. No calcification was found either macroscopically or microscopically, and the ePTFE suture retained its normal flexibility. The suture was totally encapsulated with host tissues composed of dense fibrous tissue covered with endothelial cells.

Chordae Tendineae↗
PubMed2001

[Tricuspid valve replacement using right heart bypass in patient with liver cirrhosis].

A successful case with liver cirrhosis underwent re-tricuspid valve replacement (TVR) using right heart bypass is reported herein. A 59-year-old lady previously undergone tricuspid valve replacement with bioprosthetic valve had suffered from exertional fatigue as the feature of congestive heart failure. She also presented severe liver dysfunction owing to chronic hepatitis and cardiac liver cirrhosis. She was diagnosed with structural deterioration of bioprosthesis in tricuspid position. She underwent re-TVR with right heart bypass consisted of centrifugal pump, heparin coating circuit and blood reservoir. This system lacked of membranous oxygenator in order not to activate various kinds of chemical mediator which leads to postoperative liver dysfunction. Postoperative course was uneventful and she is doing well 1 year after the operation. Although the mortality of the TVR in the patient with cirrhosis remains still high, this new technique seems to provide better outcome in this kind of patients.

Bioprosthesis↗
PubMed2001

[Anesthetic management for the correction of pectus excavatum using pectus bar under video-assistance].

We report anesthetic management for a child undergoing Nuss operation, a minimally invasive operation which requires neither cartilage incision nor its resection for correction of pectus excavatum. The patient was a 7-year-old boy with the funnel index 5 and the mediastinal shift to the left. General anesthesia with endotracheal intubation was induced and maintained with nitrous oxide, sevoflurane and fentanyl. Thoracic epidural anesthesia was used with 0.125% bupivacaine to supplement analgesia. When the curved bar was passed under the sternum with the aid of an endoscope, sinus tachycardia occurred and continued for 5 minutes but subsided without medication. Otherwise operative course was uneventful with negligible blood loss. After surgery, the patient was kept at bed rest for 2 days, receiving epidural patient-controlled analgesia combined with sedation with midazolam with good results. He was allowed to sit 3 days, to walk 5 days and discharged 10 days postoperatively.

Analgesia, Patient-Controlled↗
PubMed2001

Differences in adaptation to growth of children between internal thoracic artery and saphenous vein coronary bypass grafts.

BACKGROUND: It is not known how the internal thoracic artery (ITA) and saphenous vein graft (SVG) adapts to somatic growth of pediatric patients who underwent coronary artery bypass grafting (CABG). METHODS: Twenty-two ITAs and 6 SVGs in 17 patients who underwent at least three postoperative catheterizations with biplanar cineangiography and followed for a minimum of 5 years were evaluated. We evaluated the length, diameter and curvature of the grafts by cineangiographies which were performed at 1 month, 1 year, 5 years and more than 5 years postoperatively. RESULTS: The length of the ITA (1-month: 117+/-31 mm, 1-year: 134+/-32 mm, 5-years: 146+/-28 mm, and >5-years: 155+/-34 mm, p=0.032) and diameter of the ITA (1.4+/-0.4 mm, 2.0+/-0.7 mm, 2.3+/-0.6 mm and 2.6+/-0.6 mm, p<0.0001) significantly increased over time, but neither the length nor diameter of the SVG length: 121+/-33 mm, 119+/-29 mm, 119+/-25 mm and 126+/-1 mm, p=0.9907; diameter: 4.1+/-1.0 mm, 3.9+/-0.7 mm, 4.0+/-0.8 mm and 3.3+/-0.4 mm, p=0.5784) increased. Although the ITA exhibited no change in curvature over time (1 month: 1.15+/-0.07, late: 1.15+/-0.07, p=0.8490), the curvature of the SVG significantly decreased over time (1 month: 1.42+/-0.19 and late: 1.25+/-0.16, p=0.0277). The percent segmental length of ITAs were changed little from early to late after CABG (1 month: proximal: 33.7+/-7.0%, middle: 33.3+/-7.9% and distal: 32.9+/-7.9%, vs late: 34.3+/-7.2%, 33.2+/-7.9% and 32.5+/-7.9%, p=0.937). CONCLUSIONS: ITAs grow in proportion to somatic growth, while SVGs course in a more linear fashion in adapting to patient growth.

Adaptation, Physiological↗
PubMed2001

[Perioperative management of a child with congenital nephrogenic diabetes insipidus].

The key point in perioperative management of a patient with congenital nephrogenic diabetes insipidus is fluid and electrolytes management. Since the urine of these patients consists mainly of solute free water, replacement fluids should be fluids which provide free water. A 2-year-old girl with congenital nephrogenic diabetes insipidus was scheduled for dental extraction. Her daily fluid intake was 10 liter. She had a history of recurrent fever, polyuria and polydipsia since 2 months of age. Her previous perioperative course for gastric volvulus at another hospital was complicated with postoperative hyponatremia and convulsion. A venous line was secured the day before surgery and 5% dextrose in water was infused at a rate of 12 ml.kg-1.hr-1. Intraoperative infusion was mainly with 5% dextrose in water combined with maintenance fluid. Five hours after surgery oral intake was started. Her intraoperative electrolytes levels were low (Na 133 mEq.l-1, K 2.8 mEq.l-1), but otherwise her perioperative course was uneventful.

Anesthesia, Inhalation↗
PubMed2001

[Developing the best and the brightest in academic surgery for next generation].

Major advances have been achieved in surgery during the past century and further dynamic changes are expected along with progress in immunology, tissue and mechanical engineering, etc. in the 21st century. However, fewer medical students will choose the surgical field as their specialty, primarily due to the long training period, and inadequate income as compared to the heavy workload. To recruit the best and the brightest students in surgery, early exposure to the positive aspects of the surgical field is desirable. The training system should be further refined, and a sufficient number of positions with appropriate remuneration must be mode available.

Education, Medical, Graduate↗
PubMed2001

[Recovery characteristics of propofol anesthesia in pediatric outpatients; comparison with sevoflurane anesthesia].

We compared recovery characteristics of propofol anesthesia with those of sevoflurane anesthesia in pediatric outpatients. One hundred and four children, 3 months to 6 years of age, ASA physical status 1 or 2, were randomly assigned to following four groups; sevoflurane (group S), propofol (group P), sevoflurane with premedication (group MS), or propofol with premedication (group MP). Midazolam 0.5 mg.kg-1 and famotidine 1 mg.kg-1 were administered orally 30 min before the induction in the MS and MP group. Recovery from anesthesia, agitation, and postoperative pain were evaluated. The time intervals from the end of surgery to extubation and to discharge from the hospital were recorded. The incidence of vomiting and use of analgesic drugs were also checked. The emergence from anesthesia was slower with propofol anesthesia than with sevoflurane anesthesia, but the time to discharge from the hospital was not significantly different among the four groups. Incidence of agitation was higher in S group compared with P group, but there were no differences between MS and MP. Postoperative pain was similar among the four groups. There were no differences in the incidence of vomiting. Propofol anesthesia provided slower emergence and less agitation compared with sevoflurane anesthesia.

Anesthesia Recovery Period↗
PubMed2001

[Perioperative management of twins with prenatally diagnosed congenital diaphragmatic hernia].

Congenital Diaphragmatic Hernia (CDH) occurs in one of every 2000-3000 births, and most of them are sporadic, and therefore recognized as a circumstantial event. But its occurrence in 85 children among the 40 families is also reported, and some reports suggest that an autosomal recessive gene may be responsible for this disease. We experienced identical twins (babies A and B) both with prenatally diagnosed CDH. They were delivered by emergent cesarean section at 33 weeks of gestation with birth weight of 1857 g and 1561 g, respectively. They were intubated immediately after birth, and ventilated with high frequency oscillation. Baby A presented persistent pulmonary hypertension of newborn, and received nitric oxide inhalation. At the age of 2 days, both of them were stabilized and underwent repair of CDH. After the repair, baby A developed perforation of ileum, airway bleeding and retinopathy of prematurity (ROP), and needed 28 days before extubation. Baby B also developed ROP, but had no other problem, and the trachea was extubated at the age of 12 days. They are the seventh pair reported in the world literature.

Diseases in Twins↗
PubMed2001

[Aortoesophageal fistula due to ruptured thoracic aortic aneurysm: case report of successful primary reconstruction of esophagus].

We report a successful surgical case of 78-year-old woman with aortoesophageal fistula subsequent to the operation for sealed rupture of thoracic aortic aneurysm. She underwent one-stage operation consisted of esophagectomy, transmediastinal interposition of the stomach and esophagogastroanastomosis, to re-establish the gastrointestinal tract. The patient recovered well postoperatively without infection.

Aged↗