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Biomedical subjects

F Yamazaki

Publications and source records attributed to F Yamazaki.

At least 91 records · Page 5Linked to original sources
PubMed1990

Evaluation of a bronchial anastomosis by laser Doppler velocimetry.

Healing after bronchoplasty was evaluated by assessing the bronchial mucosal blood flow by laser Doppler velocimetry in dogs. Bronchoplastic surgery at the right main bronchus was performed and bronchial mucosal blood flow was determined by laser Doppler velocimetry at proximal and distal sides of the anastomosis before and after operation. Four experimental groups were established. After operation the blood flow was adequately preserved, and healing of the anastomosis site was satisfactory in the minimum detachment group and steroid-treated group. Mucosal blood flow was markedly reduced in both proximal and distal sides in the extensive detachment group. The extent of the reduction in the blood flow was smaller in the omentum dressing group than in the extensive detachment group. The state of healing of the anastomosis site was closely related to the bronchial mucosal blood flow.

Anastomosis, Surgical↗
PubMed1990

[Left ventricular myxoma with mucocutaneous myxoid tumors--a case report].

A surgical treatment of left ventricular myxoma arising from the anterior wall of the left ventricle is reported. A 32 year old man with a history of transient syncopal attack had an echocardiographic diagnosis of left ventricular myxoma. He previously had had myxoid tumors excised from the nose and from the posterior part of the left thigh. Cardiac surgery was performed under extracorporeal circulation on December 20, 1989. A friable, gelatinous 5 cm long myxoma with a diameter of 3 cm was excised from the left ventricule. The postoperative course was uneventful. The clinical characteristics in all the reported cases of cardiac myxomas with associated myxoid tumors of the skin are reviewed. Cardiac myxomas in patients with mucocutaneous myxoid tumors have an atypical biological behavior with early development of myxomas, atypical location, multiple tumors and high rate of recurrent myxomas.

Adult↗
PubMed1989

An evaluation of the tolerance of the autotransplanted canine lung against warm ischemia.

Left lung autotransplantation was performed in mongrel dogs to examine the limitation of tolerance of the deflated lung against warm ischemia in a warm ischemic time (WIT) range of 60-360 minutes. The animals were divided into the 4 following groups according to the duration of WIT and the use of heparin: Group 1; WIT 60-120 min., heparin (-), Group 2; WIT 120-240 min., heparin (+), Group 3; WIT 240-360 min., heparin (+), and Group 4; WIT 240-360 min., heparin (-). All the Group 1 animals tolerated a right pulmonary artery ligation on the 6th postoperative day, but some of the Group 2 animals died immediately after the reimplantation due to pulmonary edema. All the Groups 3 and 4 animals died. The PaO2 values during the right pulmonary artery occlusion, immediately after the reimplantation, correlated well with the survival of the animals. The maximum tolerable WIT of the deflated dog lung was considered to be 120 minutes.

Animals↗
PubMed1989

Application of laser Doppler velocimetry to lung transplantation.

The relationship between healing of a bronchial anastomosis and regional blood flow was studied in adult mongrel dogs after allotransplantation of the left lung. Animals were divided into the following three groups according to the immunosuppressive regimen. Group A: no immunosuppressive treatment (n = 7); Group B: azathioprine (5 mg/kg/day) and prednisolone (2 mg/kg/day) (n = 4); Group C: cyclosporine (20 mg/kg/day) (n = 4). The mucosal blood flow was examined serially after transplantation with laser Doppler velocimetry (LDV) at the tracheal bifurcation of the recipient (1st LDV) and at the bifurcation of the upper lobe bronchus of the transplanted lung (2nd LDV). The LDV values were expressed as a ratio to the preoperative values at the same site. Healing of the bronchial anastomosis was also assessed macroscopically with a fiberoptic bronchoscope and microscopically. The 2nd LDV value of the animals in group A at 13 days after transplantation remained low (32.9 +/- 27.6%). The 2nd LDV value in group B, although not significantly different from group A, had recovered to the preoperative level by that time (93.7 +/- 23.4%). By contrast, the 2nd LDV value in group C remained significantly higher than that in group A (119.9 +/- 23.0%, P less than 0.05). The 1st and 2nd LDV values were reduced in animals having infection at the bronchial anastomosis, even those in groups B and C. Bronchial mucosal blood flow appeared to be affected by infection and rejection of the transplanted lung, and to correlate closely with the healing of the bronchial anastomosis. This LDV method is useful to evaluate bronchial mucosal blood flow in experimental, and possibly in clinical, fields.

Animals↗
PubMed1989

A method for safe twelve-hour pulmonary preservation.

The clinical application of lung transplantation is severely limited by the shortage of suitable donor organs. Current techniques of lung preservation allow a maximum of 4 to 6 hours of safe ischemic time. The function of canine left lung allografts stored for 12 hours after being cooled by pulmonary artery flush was studied. Two types of flush solution were used: group I; Euro-Collins solution; group II, low-potassium-dextran solution. Lung function was studied immediately and 3 days after transplantation. This protocol enables study of acute preservation-related lung injury and the delayed manifestations of ischemic and reperfusion injury after a 3-day period of recovery. Inflatable cuffs were placed around each pulmonary artery at operation and were attached to subcutaneous injection ports. Temporarily occluding either pulmonary artery allowed independent study of the native or transplanted lung. Using this model, we were able to demonstrate reliable and reproducible preservation of lungs for 12 hours. The low-potassium-dextran solution provided significantly better immediate function of the preserved lung than the Euro-Collins solution: arterial oxygen tension 509 +/- 15 mm Hg versus 111 +/- 16 mm Hg (p less than 0.0001). Function on the third day was excellent for both groups. Pulmonary artery pressure, pulmonary vascular resistance, and carbon dioxide tension were not significantly different between the groups immediately or on day 3.

Animals↗
PubMed1989

[Histological observations of immunosuppressive effects of FK-506 in canine lung allotransplantation].

The Immunosuppressive effects of FK-506 were studied histologically in allotransplanted canine lungs. FK-506 was administered daily in a dose of 0.15 mg/kg after left lung allotransplantation. Nine dogs underwent open lung biopsy on the 7th postoperative day (p.o.d.). Mild mononuclear cell infiltrations around small vessels (MNC cuffings), which suggested an early phase of rejection, were observed in 2 dogs. Two dogs were sacrificed on the 14th and 2 on the 21st p.o.d. MNC cuffings were observed in the lung of one dog and in the bronchial submucosa of 2 dogs. Six dogs were sacrificed on the 28th p.o.d. MNC cuffings were observed in the lungs of 3 dogs and in the bronchial submucosa of 5 dogs. The MNC cuffings were of nearly the same extent in the lung and in the bronchial submucosa of most of the dogs. Alveolar structures were well in all the dogs and the bronchial epithelium in all except 2 of the dogs sacrificed on the 28th p.o.d. preserved. Arterial blood gas was examined before and 20 min. after right hilar ligation in 3 dogs on the 28th p.o.d. The PaO2 (228 mmHg, 312 mmHg, 217 mmHg at FiO2: 0.5, tidal volume: 20 ml/kg, respiratory rate: 20/min) and PaCO2 after rt, hilar ligation indicated that the transplanted lung was functioning well in these dogs. The present study suggests that FK-506 could be a potent immunosuppressive agent in lung transplantation. As 4 of the 14 dogs used in this experiment died from severe diarrhea caused by FK-506, further studies are needed to determine the suitable dose and route of administration of FK-506.

Animals↗
PubMed1989

[Technical problems on right lung transplantation].

This report describes the technique of the allo-transplantation of the right lung of an adult mongrel dog. Compare to the transplantation of the left lung, we found several pitfalls in the right lung transplantation. 1) The intraatrial groove of the recipient must be divided carefully just at the middle of the right and the left atrium in order to make a generous cuff for the left atrial anastomosis. 2) It is preferable to divide azygos vein to perform easy anastomosis of right pulmonary artery and right bronchus. 3) Care must be taken to make left atrial cuff in donor lung since we did not divide intraatrial groove in the donor animal. It was necessary to make the left atrial cuff with a part of the right atrium attached.

Anastomosis, Surgical↗
PubMed1989

The effect of ischemic time and temperature on lung preservation in a simple ex vivo rabbit model used for functional assessment.

Despite 25 years of research in lung transplantation, little progress has been made in methods for improving lung preservation. To evaluate many factors that may affect lung function after preservation, we have developed a simple, reliable, and inexpensive animal model. This consists of an isolated rabbit lung preparation perfused with blood and ventilated with a closed-circuit system. Heart-lung blocks were harvested and the left lung was assessed after ligation of the right pulmonary artery and right main-stem bronchus. On completion of a storage period, the left lung was ventilated and perfused with fresh rabbit venous blood at a rate of 40 ml/min for 10 minutes. Assessment of lung function included gas analysis of infused and effluent blood, oxygen uptake, mean pulmonary artery perfusion pressure, and mean airway pressure. A control group and six preservation groups were evaluated, each with different storage temperatures (38 degrees C, 34 degrees C, 23 degrees C, 15 degrees C, 10 degrees C, and 4 degrees C). For each temperature, ischemic periods ranging from 1 to 30 hours were studied. In the control group, the lungs were assessed immediately after being harvested. In the preservation groups, the lungs were kept partially inflated, stored at a predetermined temperature by immersion, and later assessed after variable ischemic periods. Our studies demonstrated the following: (1) The degree of impaired lung function produced by ischemia is reflected by a decrease in oxygen uptake and in oxygen tension of the effluent pulmonary venous blood and an increase in pulmonary artery perfusion pressure; (2) hypothermia improves ischemic tolerance; (3) preservation of lung at 10 degrees C is superior to preservation at 15 degrees C and 4 degrees C. This screening model has allowed evaluation of independent multiple factors and methods pertinent to lung preservation and enables one to assess lung function reliably and rapidly.

Animals↗
PubMed1988

Mechanism of interferon-gamma action. Characterization of indoleamine 2,3-dioxygenase in cultured human cells induced by interferon-gamma and evaluation of the enzyme-mediated tryptophan degradation in its anticellular activity.

Induction by interferon-gamma of indoleamine 2,3-dioxygenase (a tryptophan degradation enzyme) was examined with 11 human cell lines. The enzyme induction was demonstrated in 7 of the 11 cell lines. The induced enzyme in each of the 7 cell lines was identical to the enzyme purified from human placenta, as evidenced by immunoblot analysis with a monoclonal antibody specific to the placental one. The extent of the induction varied largely with the cell line; a relatively high induction was observed with HEL (lung fibroblasts), NY (osteosarcoma), and A-431 (epidermoid carcinoma). The enzyme induction was dependent on the concentration of interferon-gamma and occurred 12-18 h after addition of interferon-gamma to the cultures. Interferon-alpha or -beta was completely ineffective in this induction. Interferon-gamma inhibited the growth of the 7 cell lines observed with the enzyme induction, and this growth inhibition was accompanied with a complete deletion of tryptophan (less than 1 microM) in the culture medium by the induction of the enzyme. For two of these cell lines, the inhibition was partially reversed by an addition of exogenous tryptophan to the medium not to be depleted. These findings indicated that the growth inhibition by interferon-gamma was in part explained by the tryptophan depletion in the medium caused by the enzyme induction.

Ascorbic Acid↗
PubMed1988

Familial multiple neurilemoma. A case report.

A case of familial multiple neurilemoma is reported. A 59-year-old man with five neurilemomas was treated. Fifteen of his 22 family members had had soft-tissue tumors. Ten neurilemomas had been diagnosed microscopically in five members of the family. There were no symptoms related to von Recklinghausen's disease. This case seems to be a forme fruste or related form of von Recklinghausen's disease.

Cauda Equina↗
PubMed1986

Central effects of N-allyl,N'-methyl-barbital and N-allylmethyprylon in mice.

Pharmacological activities (hypnotic, anticonvulsant and convulsant activities, acute toxicity and pentobarbital (PB) synergism) of N-allyl,N'-methyl derivatives of barbiturates and related N-allyl substituted compounds were studied in mice. N-Allylhexobarbital (AHB), N-allylglutethimide (AGI) and N-allylmethyprylon (AMP) showed hypnotic activity. N-Allyl,N'-methyl derivatives of barbital (B), phenobarbital (PheB) and PB (AMB, AMPheB and AMPB), AHB and AMP exhibited anticonvulsant activity against pentylenetetrazol (PTZ)-induced seizures. AMP was the most potent agent among the allyl compounds tested in the protective effect against PTZ-induced seizures. N-Allyl, N'-methylallobarbital (AMAlloB) showed a weak convulsant activity at a dose of 640 mg/kg, i.p. All allyl compounds tested showed potentiation of the PB-induced sleep. AMB prolonged the PB-induced sleep 30-fold as compared with the control. These results indicate that AMB, AMP and the other N-allyl compounds possess some depressant effects on the central nervous system.

Allyl Compounds↗