Biomedical subjects

Y Fujihara

Publications and source records attributed to Y Fujihara.

At least 19 recordsLinked to original sources

PubMed1992

[Clinical evaluation of stent placement for tracheal and bronchial stenosis].

Expandable metallic stents were successfully introduced in 7 patients, including 4 with left main bronchial stenosis caused by bronchopulmonary tuberculosis, 2 with main bronchial stenosis caused by lung cancer and one with tracheal stenosis caused by adenoid cystic carcinoma. The length of stenosis was 1.5-5 cm. The stents were 1.5-2.5 cm long with barbs, and their full expanded diameter was 1.5 cm. Balloon dilatation was performed before stenting in all cases. The stents were inserted by using a 10-12 Fr catheter. In all patients except the one with tracheal stenosis, stents were introduced under local anesthesia without any difficulties. No migration of stents occurred. After stent placement, there were no respiratory difficulties, and radionuclide lung perfusion scan and chest radiographic findings such as lung atelectasis showed marked improvement in three cases. Combined therapy of stent placement and bronchial arterial infusion chemotherapy showed marked effectiveness in one case with lung cancer. Expandable metallic stents were very useful in eliminating tracheobronchial stenosis symptoms.

Adult↗

PubMed1992

[Experimental study of water jet angioplasty].

A newly invented angioplasty by using water jet energy was investigated for evaluating its safety and effectiveness in 3 dogs. The water jet was produced from a small tip nozzle (0.2 mm in diameter) of catheter by injecting 20 ml of diluted contrast medium. By using this method recanalization of femoral arterial occlusion produced by fresh thrombi was achieved in all 3 dogs. Post recanalization angiography showed no apparent small vessel occlusions. Injection apart more than 5 mm from the inner surface of human aorta provoked no apparent changes histopathologically. Water jet angioplasty may be useful in treating vascular occlusive disease.

Animals↗

PubMed1991

[Experimental study of endoesophageal and intestinal expandable metallic stent placement].

Gianturco expandable metallic stents were implanted into the esophagus and small intestine of 10 rabbits in order to evaluate the influence of wire stents on the gastrointestinal tract. The stents were constructed of 0.010 inch stainless steel wire. The relaxed diameter of the stents was 12-14 mm and the length was 10 mm. Except for one stent placed in the small intestine, the stents did not migrate and were covered with thickening mucosal epithelium. The mucosal inflammatory changes were slight, but severe intestinal adhesions were noted. The findings in the two groups were not significantly different at three and six weeks. Five rabbits died within three weeks of intestinal disorders caused by severe intestinal adhesions and/or perforations. The experimental data showed that implantation of metallic wire stents into the gastrointestinal tract resulted in severe damage to the esophagus and small intestine of rabbits.

Animals↗

PubMed1990

[Experimental study of the intraurethral placement of expandable metallic stents].

Various types of Gianturco expandable metallic stents were implanted into the urethra of four dogs in order to evaluate the suitable expandability of the stents in urethra and also to determine the effect of the stents on the urethral wall. The stent of 1.5 cm in length and constructed of 0.010 inch round stainless steel wire with twelve zigzag bends showed the suitable expandability on the canine urethra compared to the other stents. The urethra remained patent and the inflammatory changes on the urethral wall were moderately noted. No hematuria or calcifications around the stents were noted in any dogs. The experimental data showed a potential clinical application.

Animals↗

PubMed1990

[In vitro study of radiofrequency thermal angioplasty].

We performed some in vitro experiments using a radiofrequency thermal angioplasty instrument. The distribution of heat emitted from the hot tip of the device was evaluated in an agar phantom by thermography and it produced a concentric circular pattern. The temperature of the hot tip was about 290 degrees C when measured by thermocouples in the air. When the RF probe approached perpendicularly to the cadaver arterial wall, a crater with charring and coagulating necrosis was formed. However, when the RF probe traveled parallel to the arterial wall, as in normal practice, it did not seem to perforate the artery. The device could ablate non-calcified atheromatous plaque.

Angioplasty, Balloon↗

PubMed1990

[Experimental study of endotracheal expandable metallic stent placement].

Various types of Gianturco zig-zag wire stents were implanted into the trachea of three dogs in order to evaluate the suitable conditions of the endotracheal wire stent. The stents were constructed of 0.018, 0.016 and 0.013 inch stainless steel wire respectively. The relaxed diameter of the stents was 3.0 cm and their length were 2 cm, 3 cm, and 4 cm respectively. The stent of 2 cm in length and constructed of 0.013 inch showed minimum pathologic changes to the trachea of the dog compared to the other stents, and also showed the covering of ciliated, columnar epithelium over the stent surface. The experimental data showed that it was possible to use the stent in the tracheobronchial tree of dogs and also showed a potential clinical application.

Animals↗

PubMed1990

[Clinical experience of percutaneous transluminal angioplasty and expandable metallic stent placement for Budd-Chiari syndrome with massive thrombus in the inferior vena cava; report of a case].

A 72-year-old female who had suffered from lower extremity edema and liver cirrhosis due to Budd-Chiari syndrome with massive thrombus in IVC was treated by PTA and placement of self-expandable metallic stent. Thrombolysis therapy after PTA was very effective. Five months later, she had no clinical symptom due to IVC stenosis.

Aged↗

PubMed1990

[Physical properties of expandable metallic stents; including the procedure of stent production].

Nowadays expansile force of self-expandable metallic stent is estimated by only wall-distending pressure P. We estimated the expansile force of the stent by not only P but also F. F expressed the degree of digging into the vessel wall and was defined as a force per one unit length of wire. P and F were thought to be useful in selecting the best stent. We also introduced the procedure of stent production.

Biomechanical Phenomena↗

PubMed1990

[Experience of expandable metallic stent for tuberculosis bronchial stenosis].

A 41-year-old female who had suffered from a severe left main bronchial stenosis due to bronchial tuberculosis was treated by implantation of self-expandable metallic stent after dilating the stenosis by balloon catheter. After placing the stent symptoms such as dyspnea were disappeared completely. Four months later, the patient can tolerate to do jogging.

Adult↗

PubMed1989

Dose escalation study of recombinant human granulocyte-colony-stimulating factor (KRN8601) in patients with advanced malignancy.

To evaluate the toxicity and efficacy of recombinant human granulocyte-colony-stimulating factor (rh G-CSF) administered with intensive chemotherapy, 39 patients with advanced pulmonary cancers were enrolled in a dose escalation trial of rh G-CSF. Three days after initiation of chemotherapy rh G-CSF was administered i.v. for 14 consecutive days at five dose levels (50-800 micrograms/m2). Absolute neutrophil counts showed a dose-dependent increase with an increasing dose of rh G-CSF and the durations of neutropenia (less than 1000/mm3) shortened significantly at doses of 200, 400, and 800 micrograms/m2 compared to those at 50 micrograms/m2 (P less than 0.01). The duration of neutropenia was shortened significantly at all five dose levels following treatment with rh G-CSF compared to treatment without rh G-CSF (P less than 0.05). Adverse side effects associated with rh G-CSF administration were fever higher than 38 degrees C (21%), chest pain, and low back pain (13%). No intolerable side effects were experienced. It can be concluded that rh G-CSF is effective in shortening the duration of neutropenia following intensive chemotherapy at a dose level of 100 to 200 micrograms/m2 i.v. a 400-micrograms/m2 dose of rh G-CSF is recommended in patients with prior treatment because of the possibility of a lower bone marrow response.

Adult↗

PubMed1989

Intrahepatic delivery of glutathione by conjugation to dextran.

Glutathione was covalently attached to dextran (T-40) by the CNBr activation method. The compound obtained was a water-soluble powder containing 10 (w/w%) glutathione, which was gradually released from the conjugate in aqueous media. Mice depleted of glutathione by treatment with buthionine sulfoximine, a potent inhibitor of gamma-glutamylcysteine synthetase, exhibited a significant increase in hepatic glutathione level after intravenous injection of the conjugate. In mice given a lethal dose of acetaminophen, the survival rate increased progressively with coadministration of the conjugate, whereas little improvement was found when free glutathione was given. The conjugate maintained the serum transaminase activities at lower level after acetaminophen administration. These findings suggest that the dextran conjugate of glutathione is transported into hepatic cells and is intracellularly hydrolyzed to free form, which protects mice from hepatotoxicity due to acetaminophen.

Acetaminophen↗

PubMed1989

Effects of glutathione, as the dextran conjugate, on acetaminophen-induced hepatotoxicity.

Glutathione was covalently attached to dextran (T-40) by the CNBr activation method. In mice given a lethal dose of acetaminophen, the 30-d survival rate increased progressively with coadministration of the conjugate, whereas little improvement was found when free glutathione was given. The dextran conjugate of glutathione maintained the serum transaminase activities at lower levels after acetaminophen administration, giving effective protection against acetaminophen hepatotoxicity.

Acetaminophen↗

PubMed1986

Contribution of calcium ion sequestration by polyoxyethylated nonionic surfactants to the enhanced colonic absorption of p-aminobenzoic acid.

Enhanced absorption of p-aminobenzoic acid (PABA) from the colon by polyoxyethylated nonionic surfactants was investigated using an in situ perfusion technique. The order of their absorption-enhancing effect was as follows: polyoxyethylene lauryl ether greater than polyoxyethylene sorbitan fatty acid esters approximately equal to polyoxyethylene fatty acid esters. The coexistence of calcium chloride in the perfusing solution caused a partial reverse in this enhancement. The calcium ion sequestration capacity of the surfactants was correlated with their ability to enhance colonic absorption of PABA. The findings suggest that calcium ion sequestration by the surfactants contributes to their enhancement of the colonic absorption of PABA.

4-Aminobenzoic Acid↗

PubMed1986