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H Yokomise

Publications and source records attributed to H Yokomise.

87 records · Page 5Linked to original sources
PubMed1991

The effect of pulmonary arterial flow and positive end-expiratory pressure on retrograde bronchial mucosal blood flow.

Bronchial viability within the first few days after lung transplantation depends on collateral blood flow from the pulmonary to the bronchial circulation. In the present study the relationship between pulmonary arterial flow and retrograde bronchial blood flow, and the effect of positive end-expiratory pressure on bronchial blood flow were evaluated by laser Doppler velocimetry in an isolated in situ lung perfusion model. Nine adult mongrel dogs were exsanguinated by way of a left atrial cannula. Blood was pumped by a roller pump into the main pulmonary artery. Lungs were perfused at random flow (in 0.5 L/min increments) at rates of 1 to 3 L/min. Steady-state laser Doppler velocimetric measurements at each level of flow were made at the tracheal carina and both bronchial carina. Pump flow was then set at baseline cardiac output and positive end-expiratory pressure was applied. Steady-state laser Doppler velocimetric measurements were obtained at each level of positive end-expiratory pressure (5 cm H2O and 10 cm H2O). Bronchial blood flow correlated well with pulmonary arterial flow (for the tracheal carina; rs = 0.912 and p less than 0.0005; for the right bronchial carina, rs = 0.799, p less than 0.0005; for the left bronchial carina, rs = 0.917, p less than 0.0005; where rs is the common correlation coefficient). The bronchial blood flow at the left bronchial carina and the right bronchial carina were significantly higher than at the tracheal carina (p less than 0.005 and p less than 0.05, respectively). At baseline cardiac output, bronchial blood flow in the in situ model was approximately 50% lower than observed in the intact animals. Positive end-expiratory pressure increased the bronchial blood flow at the tracheal carina and both bronchial carina (p less than 0.05).

Animals↗
PubMed1991

Plasma atrial natriuretic factor concentrations in a canine model of right heart pressure overload.

Two studies were carried out in order to evaluate the plasma atrial natriuretic factor (ANF) concentrations, as well as hemodynamic and renal profiles in a chronic canine model of right heart pressure overload induced by pulmonary artery (PA) banding. In study I (n = 6), the animals were submitted to a gradual increase in pressure to clarify whether an increase in pressure or atrial distension was the main stimulus to ANF secretion. In study II (n = 6), right heart pressure overload was produced more rapidly, resulting in fluid retention and weight gain, thereby completing the model of right heart failure, and allowing an evaluation of the mechanisms involved in ANF resistance. In study I there were significant increases in right atrial pressure over baseline at 20 weeks, ANF levels at 24 weeks and right atrial area at 28 weeks following PA banding. In study II right heart pressures and ANF levels were higher than baseline at 12 weeks (p less than 0.0001), and fluid retention developed between 12-24 weeks in all dogs. The results suggest that increased right heart pressure, rather than atrial size, is a primary stimulus to ANF secretion in chronic right heart pressure overload. Despite the increases in right atrial pressure, clinical fluid retention occurred only with elevations of renin and aldosterone.

Aldosterone↗
PubMed1990

Systemic venous aneurysms.

A case of superior vena cava aneurysm combined with aneurysm of the left innominate vein is presented. For the diagnosis, it is important not only to apply imaging techniques such as superior vena caval angiography, radioisotopic angiography, and computed tomographic scans but also to have a concept of this entity in mind.

Adolescent↗
PubMed1990

The superiority of an extracellular fluid solution over Euro-Collins' solution for pulmonary preservation.

Limited donor supply is the major factor restricting the application of lung transplantation. A uniformly reliable method of lung preservation would improve donor organ availability. At present, Euro-Collins' solution, an intracellular fluid-type solution, is most widely used in organ preservation. However, we have previously shown that initial pulmonary flush with an extracellular-type solution (low-potassium dextran solution [LPD]) provided better pulmonary preservation than Euro-C. In the present study, we used an in vitro-ventilated, blood-perfused rabbit lung model to examine whether the mechanism for this improvement was related to the effect of LPD during pulmonary flush or its effect during storage. Rabbit lungs were harvested and stored after pulmonary flush with different solutions (group 1: 400 ml of LPD; group 2: 400 ml of Euro-C; group 4: 300 ml of Euro-C followed by 100 ml of LPD; n = 5 in each group). The lungs were then preserved at 10 degrees C for 18 hr and reperfused with fresh venous blood. After 10 min of reperfusion, lungs in group 1 showed the highest PO2 (group 1: 124.4 +/- 7.7 mmHg; group 2: 46.2 +/- 9.4 mmHg P less than 0.01). Lungs in both group 3 and group 4 showed better lung function and lower wet/dry weight ratio than those in group 2. We conclude that LPD provides better lung preservation by its effects both on pulmonary flush and on storage.

Animals↗
PubMed1990

The effect and optimal time of administration of verapamil on lung preservation.

Calcium channel blockers have recently been shown to improve pulmonary and myocardial preservation. The effect of verapamil on hypothermic lung preservation was investigated using an isolated ventilated rabbit lung perfusion model. In phase 1, preserved lungs were not flushed prior to extraction. Four groups of five animals were studied: group 1 (no verapamil), group 2 (verapamil administration prior to extraction), group 3 (verapamil at reperfusion only), group 4 (verapamil both prior to extraction and at reperfusion). In phase 2, two groups of five animals received pulmonary artery flush with low potassium (4 mmol/L), 2% low-potassium dextran (LPD) solution; group 1 (without verapamil), group 2 (flush and reperfusion with verapamil). As in phase 1, lungs were stored for 30 hr at 10 degrees C prior to reperfusion. In phase 3, the protocol was identical to phase 2, except that the storage time was extended to 48 hr. PO2 (mean +/- SE) of effluent blood in lungs treated with verapamil prior to extraction (122.8 +/- 5.0 mmHg) was significantly increased in comparison with lungs not receiving verapamil (69.0 +/- 3.3 mmHg) or only receiving verapamil at the time of reperfusion (87.1 +/- 11.9 mmHg). Gas exchange after 30 hr storage was equivalent in lungs flushed with LPD with or without verapamil. However verapamil did provide an advantage when preservation times were extended to 48 hr (62.3 +/- 8.5 mmHg, 46.9 +/- 2.3 mmHg). Verapamil administered prior to lung extraction provides better lung function following preservation, but has benefit over LPD flush only with extended periods of preservation (48 hr).

Animals↗
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↗
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

[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↗
PubMed1986

[Serum and tissue concentrations of UFT in patients with lung cancer].

Postoperative serum and tissue concentrations of 5-FU, FT-207 and uracil were measured in 36 patients with lung cancer who were administered UFT for seven days preoperatively. The concentration of 5-FU was high in tumor tissue and lymph nodes, but very low in serum. Such differences were not observed in the FT-207 levels. Tumor concentration of 5-FU in patients administered daily doses of 600 mg was 0.151 +/- 0.099 microgram/g which was three times higher than the minimum inhibitory concentration, and higher than that seen with other doses. The histological type and T factor were not related to the tissue concentration of 5-FU. Lymph node metastasis was not related to the concentration of 5-FU in the lymph nodes. The optimal daily dose of UFT for patients with lung cancer was considered to be 600 mg.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

Combined therapy with FK-506 and cyclosporine for canine lung allotransplantation: immunosuppressive effects and blood trough levels.

The therapeutic and adverse effects of FK-506 and cyclosporine used in combination were examined in 35 adult mongrel dogs with allotransplantation of the left lung. The experimental animals were allocated to six groups: group A, optimal dose of FK-506 (n = 5, FK-506 0.1 mg/kg/day, intramuscularly); group B, optimal dose of cyclosporine, (n = 5, cyclosporine 20 mg/kg/day, by mouth); group C (n = 5, FK-506 0.03 mg/kg/day, intramuscularly); group D (n = 5, cyclosporine 6 mg/kg/day, by mouth); group E (n = 5, FK-506 0.03 mg/kg/day+cyclosporine 6 mg/kg/day); and group F (n = 10, FK-506 0.05 mg/kg/day+cyclosporine 10 mg/kg/day). The animals were killed on postoperative day 28 or when extreme deterioration had developed. In groups C and D, the grafts underwent moderate to severe rejection. The treatment in group E resulted in insufficient immunosuppression, although additional effect was noted. The rejection was suppressed at least as strongly in group F as in groups A and B. One death occurred in each of groups A and F from hematemesis. The blood concentrations of FK-506 and cyclosporine in group E were not higher than in groups C and D. The whole blood concentrations of FK-506 deviated less, and they were superior to the serum concentrations as a monitor. The combination of FK-506 and cyclosporine at one half of their optimal doses suppressed the rejection almost completely and did not increase the adverse effects.

Animals↗