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Biomedical subjects

N Miyazaki

Publications and source records attributed to N Miyazaki.

160 records · Page 9Linked to original sources
PubMed1978

Protease-induced experimental emphysema: the relationship between elastolytic activity and emphysema induction.

Induction of experimental emphysema by protease was performed with several proteases both in vivo and in vitro to compare the ability of inducing emphysematous change and their elastolytic activity. The following results were obtained. 1) Only elastase and papain have emphysema inducing capacity. Emphysematous changes induced by elastase in vitro were dose dependent. But papain has no genuine elastolytic activity. Nature of the emphysema-inducing capacity of papain remains obscure. 2) Advantages of using the isolated lung for experiment were discussed, especially for the small dose required for enzyme-instillation. Moreover, there is no interferencey by endogeneous enzyme or protease-inhibitors. 3) Guinea pig is useful for the experiemnt of emphysema-induction both in vivo and in vitro. Minimal requirement of elastase is 50 microgram in vitro and 250 microgram for in vivo experiment.

Animals↗
PubMedDate not supplied

Sensitizing effects of gallium citrate on hyperthermic cell killing in vitro.

The lethal effects of gallium citrate in combination with heat were studied using four cell lines, L5178Y, FM3A, P388 and HeLa. Cells were incubated with different concentrations (0.2 2 mM) of gallium citrate at 37 degrees C for 24 h and heated at a range of temperatures from 40-44 degrees C for various time periods up to 6 h in the absence of gallium citrate. Survival and cell viability were determined by clonogenic assay and the dye-exclusion test, respectively. All of the cell lines tested were insensitive to heat below 41 degrees C, but were very sensitive to heat above 43 degrees C. Gallium citrate was cytotoxic to these cell lines at different levels: P388 and HeLa were far more sensitive than L5178Y and FM3A. The killing effects of heat at 41 degrees C were greatly enhanced by gallium citrate in L5178Y and P388 cells. The Arrhenius analysis for the lethal effect of heat, determined by clonogenic assay, in L5178Y cells showed that the transition temperature was remarkably decreased for the gallium-treated cells from approximately 43 degrees C to 41 degrees C. The mechanism for this decrease in the transition temperature may be attributable to the additional effects of gallium citrate on energy metabolism. Preincubation with 0.05 mM gallium citrate at 37 degrees C for 7 days also enhanced heat sensitization at 41 degrees C in L5178Y. This preincubation condition may correspond to the condition for the continuous infusion of gallium that is clinically used for cancer treatment. In contrast, treatment with gallium did not greatly enhance the sensitivity of FM3A or HeLa cells to heat at 41 degrees C, but the effects of gallium were significant.

Adenosine Triphosphate↗
PubMedDate not supplied

Role of ATP in the sensitivity to heat and the induction of apoptosis in mammalian cells.

Heat-induced cell death and apoptosis were studied with respect to intracellular ATP. Studies on the relationship between hyperthermic cell-killing at 44 degrees C and cellular ATP levels in four cell lines grown as monolayers and six cell lines grown in suspension showed good correlations between cellular ATP levels and the sensitivity to heat. D(0) values (the dose required to reduce survival in the linear portion of the response by 63%) linearly increased with an increase in cellular ATP levels. No such changes in sensitivity to heat were observed between the cells cultured at different cell densities, regardless of the change in the cellular ATP level. These results suggest that cellular intrinsic ability to supply ATP rather than the level of pooled ATP per se is responsible for the thermal response. Heat-induced apoptosis in L5178Y cells was observed following treatment at 42 degrees C for 70 min, 44 degrees C for 20 min or 47 degrees C for 3 min, which corresponded to surviving fractions of 25, 0.6 and 0.8%, respectively, but not at 47 degrees C for 20 min, indicating that mild heat shock induced apoptosis. 2-deoxyglucose (2DG) and 2,4-dinitrophenol (DNP) increased the sensitivity to heat and affected the mode of cell death. Cells treated with 2DG and DNP (2DG/DNP) were heated at 42 degrees C for 20 min, and then incubated at 37 degrees C for up to 2h in the presence or absence of 2DG/DNP. In the absence of 2DG/DNP, the cellular ATP level recovered to 76% of the control level and DNA ladder formation was observed, whereas in the presence of 2DG/DNP, the cellular ATP level was further decreased (3-7% of the control) and no DNA fragmentation was detected. These results suggest that the inhibition of ATP synthesis is closely associated with the enhancement of sensitivity to heat and that ATP is required for the induction of apoptosis.

2,4-Dinitrophenol↗
PubMedDate not supplied

Indwelling catheter retraction because of pendulous breast.

Long-term home parenteral nutrition (HPN) is an established treatment for chronic intestinal failure. A reliable and safe vascular access is of fundamental importance to HPN patients. We have typically used a right atrial catheter attached to a subcutaneous port. We present a case of right atrial catheter retraction in a large-breasted woman with short bowel syndrome. The catheter was retracted and coiled around the reservoir in the subcutaneous pocket by motion of the patient with large breasts. Displacement of right atrial catheters is a rare but recognized complication. To avoid this complication in obese patients with large breasts, the positional changes of the breast should be determined. and the reservoir should be implanted in the area of least motion along the sternum.

Aged↗
PubMedDate not supplied

The biological and clinicopathological characteristics of right-sided colon cancer.

The biological characteristics of right-sided colon cancer were examined in 74 colon cancers with regard to clinicopathological parameters, proliferative activity and p53 expression. Significant differences between right-sided and left-sided colon cancer were found in age, tumor size, histological type and lymphatic vessel invasion. The proliferating cell nuclear antigen labeling index did not significantly differ between the two cancers. The frequency of p53 overexpression was lower in the former than in the latter. The results suggested that right-sided colon cancer did not differ from left-sided colon cancer in proliferative activity except for its tendency to be locally advanced and to differ in carcinogenesis.

Aged↗
PubMedDate not supplied

Juxta-anastomotic aneurysm in the residual infrarenal abdominal aorta.

A 72-year-old man, who had undergone an emergency operation with a tube graft for a ruptured abdominal aortic aneurysm 9 years previously presented with a recurrent true abdominal aortic aneurysm near the proximal anastomotic site. True aneurysmal formation in the juxta-anastomotic aorta proximal to the prosthetic graft as seen in this case is very rare. Since recurrent aortic aneurysms impose significant problems of diagnosis and management, procedures to prevent the recurrence of aneurysms are important in the initial operation.

Aged↗
PubMedDate not supplied

Gastroenterological surgery for patients with chronic respiratory insufficiency.

BACKGROUND/AIMS: The aim of this study was to clarify the surgical indications for patients with chronic respiratory insufficiency. METHODOLOGY: Fourteen patients with chronic respiratory insufficiency who underwent abdominal surgical procedures, were retrospectively studied. The surgical indications were carefully determined based primarily on the performance status (PS) of each patient and cardiopulmonary function tests. A PS of equal to or less than 3, which meant the patient's status required bed rest > 50% of the time, and the need for assistance in performing normal activities were all factors considered for surgical indications. RESULTS: During the period studied, two patients were excluded from the surgical indications due to the fact that one was at a terminal stage of pulmonary disease and was completely bedridden (PS = 4), while the other demonstrated active pneumonia with a considerable amount of purulent sputa. Regarding the pulmonary function tests for patients who underwent surgery, the lowest limits of those examinations were as follows: 810 ml of vital capacity (VC), 23.8% of predicted VC, 610 ml of forced expiratory volume in one second (FEV1.0), 38.6% of predicted FEV1.0, 50.5 mmHg of PaO2 while inhaling 4 liters of oxygen and 73.8 mmHg of PaCO2. No surgery related mortality or hospital death within 30 days after operation was observed. Only two patients had cardiopulmonary complications (consisting of pulmonary edema with atrial fibrillation in one patient, and acute myocardial infarction in another patient). However, neither pneumonia, prolonged ventilatory support for more than 2 days, nor the need for a tracheostomy after surgery was observed. CONCLUSIONS: Gastroenterological surgery is thus considered to be indicated even for patients with chronic respiratory insufficiency, as long as the PS can be maintained (PS of equal to or less than 3) and no active pneumonia with a considerable amount of purulent sputa is present.

Abdomen, Acute↗