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Biomedical subjects

M Watari

Publications and source records attributed to M Watari.

52 records · Page 3Linked to original sources
PubMed1999

Protective effects of pretreatment with ginsenosides on cardiac and coronary vascular function after hypothermic rat heart preservation.

Prevention of cardiac and vascular dysfunction with pretreatment has been accepted as an important factor in heart transplantation. Ginsenosides (GS) have been reported to have some beneficial effects on the cardiac and vascular system. We hypothesized that pretreatment with GS would result in an improvement of functional recovery after a 12 hour (hr) rat heart preservation. A Langendorff apparatus was applied to estimate the cardiac and vascular function in an isolated rat heart preparation. The hearts were preserved in University of Wisconsin solution at 0 degree C for 12 hr, after pretreatment with 0.9% sodium chloride or GS 100 mg/kg, respectively, in control (n = 9) and GS (n = 14) groups. After storage, the cardiac function, myocardial water content, and coronary vasodilatory response were evaluated. The GS group showed a significantly higher recovery percentage of cardiac function compared with the control group: aortic flow 81.4 +/- 21.4% versus 57.2 +/- 11.0% (p = 0.0052); coronary flow 81.4 +/- 14.5% versus 57.2 +/- 6.0% (p = 0.0001); +/- dp/dt max 72.5 +/- 16.1% and 66.0 +/- 16.1% versus 53.7 +/- 4.1% and 51.4 +/- 7.1% (p = 0.0027 and p = 0.0189) respectively. The GS group showed a lower increase in myocardial water content. With Langendorff perfusion, the endothelial and vascular smooth-muscle cell function were evaluated by an increasing percentage of coronary flow in response to acetylcholine chloride (0.3 x 10(-7) mol/liter) and nitroglycerin (0.5 x 10(-5) mol/liter). It was significantly higher in the GS group than that in the control group (19.2 +/- 8.8% and 28.0 +/- 14.1% versus 9.9 +/- 4.7% and 14.7 +/- 8.1%, p = 0.008 and p = 0.0187, respectively) at the first minute. These results suggest a protective effect on ventricular and coronary vascular function in the rats pretreated with Ginsenosides, indicating potential benefits for long-term heart preservation.

Animals↗
PubMed1999

Open stent-graft repair for acute type A aortic dissection with an intimal tear in the descending aorta.

A 47-year-old man with acute retrograde aortic dissection (Stanford type A) was treated with total aortic arch replacement and endoluminal stent-grafting for an intimal tear in the descending aorta. A stent-graft was introduced into the descending aorta via the transected arch aorta and the entry of the dissecting aneurysm was closed. Open endovascular stent-grafting via the arch aorta is an alternative for repair of acute type A aortic dissection with an intimal tear in the descending aorta, in cases where direct closure of the intimal tear is difficult.

Aortic Dissection↗
PubMed1999

A new suture technique for reconstruction of intercostal arteries during thoracoabdominal aortic aneurysmal surgery.

Reconstruction of several intercostal arteries is inevitable in surgical treatment of thoraco-abdominal aortic aneurysm. A Dacron inverted-Y shaped graft was fashioned by cutting one of two graft legs and making an elliptical patch, like a cobra-head. Once the elliptical patch was sutured to the orifices of the intercostal arteries (usually from T9 to T12) with running sutures, selective intercostal arterial perfusion was initiated. After completion of aneurysmectomy, the distal end of the elliptical patch graft was sutured to the main tube graft. This method is easier and faster and results in a decreased incidence of spinal cord injury.

Aortic Aneurysm, Abdominal↗
PubMed1998

An aortic balloon catheter incorporating a conduit for percutaneous cardiopulmonary support.

Circulatory support using both intraaortic balloon pumping (IABP) and percutaneous cardiopulmonary support (PCPS) can improve general hemodynamics; however, sometimes brain damage occurs caused by hypoperfusion. Such cerebral hypoperfusion is likely to be caused by PCPS when applying the conventional femoral cannulation. We have developed a new IABP catheter which incorporates a conduit for PCPS with an outlet at the catheter tip, the goal of which is the improvement of cerebral perfusion. The hemodynamic characteristics of this new IABP catheter were compared with those of the conventional combination of IABP and PCPS. Studies were performed by mock test using a pulsatile artificial heart. A polyvinyl chloride tube acted as the aorta with 2 branches at the proximal and distal portions representing the upper and lower portions of the body. The IABP balloon was positioned between the 2 branches, and changes in flow at the 2 branches were examined at varying PCPS flow rates. Flow in the proximal branch using the new device was greater than it was using the conventional PCPS device. We conclude that cerebral perfusion could be improved with the use of this new special IABP catheter.

Angioplasty, Balloon, Coronary↗
PubMed1998

Assessment of a new silicone tri-leaflet valve seamlessly assembled with blood chamber for a low-cost ventricular assist device.

We have developed a practical, low-cost ventricular assist device (VAD) comprising a newly designed blood chamber with a silicone lenticular sac and two silicone tri-leaflet valves (STV), made en bloc. This new VAD is seamless, can be made cost-effectively and assembled with the blood chamber and valve as one body. This novel design should reduce the incident of thrombus formation because of the absence of a junction at the connecting ring and because of the use of flexible silicone materials which have both antithrombogenecity and biocompatibility. In in vitro hemodynamics testing, a batch of 3 consecutively manufactured VADs with STVs underwent hydrodynamic functional testing. These showed less regurgitation, a lower value of water hammer phenomenon, and a slightly greater pressure gradient across the valves than a mechanical valve (MV) [Björk-Shiley monostrut valve]. The flow and pulsatile efficiency were adequate and similar to that of a VAD with MVs. In in vitro durability and hemolysis tests, a VAD with STV functioned well for 54 days and showed similar hemolytic profiles to a VAD with MVs. In an in vivo acute experiment using an adult sheep, our device was problem-free providing sufficient output as a left ventricular assist device (LVAD). Although it will be necessary to decrease the pressure gradient across this STV in the future, our device showed efficient performance as a practical land cost-effective VAD for short term use.

Adult↗
PubMed1998

[Emergency room visits by patients with exacerbations of asthma].

We retrospectively analyzed patterns of emergency room visits by patients with exacerbations of asthma from December 1995 through November 1996. A total of 591 episodes in 198 patients were reviewed. The average age was 35.8 years, ranging from 15 to 71. The largest number of visits occurred in September. The number of visits per year ranged from 1 to 22; the mean was 2.9 per year. In patients who were followed on a regular basis at our institution, serve attacks accounted for 7.1% of the total, compared with 21.6 percent at other hospitals or outpatient clinics. We suspect that this difference was related to differences in the use of inhaled steroids. At our institution, 89% of patients were taking inhaled steroids; at other hospitals or clinics, only 21% were taking inhaled steroids. Of the 198 patients, 33 fulfilled one of the following criteria: (1) endotracheal intubation for respiratory failure or respiratory arrest, (2) respiratory acidosis (pH < 7.35) without endotracheal intubation; 27% of those patients had been given a diagnosis of mild asthma before the acute exacerbation. We conclude that patient education and standard guidelines for treatment of asthma, are very important for appropriate management of asthma, to prevent exacerbations and asthma-related deaths.

Administration, Inhalation↗
PubMed1998

Three different approaches to spinal cord monitoring for the prediction of spinal cord ischemia during thoracic aortic aneurysm surgery.

We report the case of a 66-year-old man who had a descending thoracic aneurysm, diagnosed as aortitis syndrome. He subsequently underwent an aneurysmectomy under simultaneous sensory and motor spinal cord monitoring. Spinal cord ischemia was diagnosed during prosthetic replacement of the aneurysm by changes in evoked spinal cord potentials and motor evoked potentials from the lumbar spinal cord enlargement and 2 pairs of intercostal arteries were reconstructed at the level of T9 and 10. After surgery, the patient developed paraparesis below T10, but the resulting neurological deficits were overcome with postoperative rehabilitation. Simultaneous monitoring of evoked spinal cord potentials and motor evoked potentials were useful in evaluating spinal cord ischemia during aortic aneurysm surgery and in determing whether intercostal arteries should be reconstructed.

Aged↗
PubMed1997

[Clinical and diagnostic characteristics of Legionella pneumonia].

We have characterized clinical and diagnostic features in 18 cases of Legionella pneumonia. Age average of patients was 62.0 years old (male:female = 14:4) and underlying diseases were observed in 12 patients. Legionella pneumonia were diagnosed in 3, 5, 8 and 9 cases by culture, serum antibody measurement, urinary antigen detection and PCR, respectively. Sixteen cases were caused by L. pneumophila, while the other 2 cases were L. bozemanii pneumonia and L. pneumophila or L. dumoffii pneumonia. Chest X-rays of those patients showed multiple pneumonia shadows in 14 cases, alveolar shadows in 10 cases, pleural effusion in 5 cases. Blood-gas analysis on admission indicated hypoxemia in all cases with abnormal A-a DO2. Laboratory findings showed abnormal data in WBC, CRP, LDH, CPK and liver function tests (ex. GOT, GPT) in most cases. Serum antibody testing showed positive by 5 weeks after onset of pneumonia, but 10 cases of Legionella pneumonia diagnosed by other techniques were judged to be negative. In urinary antigen detection test, 6 and 2 cases showed positive 1 and 4 weeks after onset of pneumonia, respectively. Macrolide antibiotics were administered in all cases during the episode, but delay of macrolide administration was observed in 3 of 4 cases of dead outcome. Serum antibody measurement, urinary antigen detection and PCR, in addition to culture to bacteria, may be required for exact diagnosis of Legionella infection.

Adult↗
PubMed1997

Ammonia determination as an early indicator in experimental superior mesenteric artery occlusion.

Superior mesenteric artery occlusion (SMAO) is often fatal. An indicator which enables the early diagnosis of SMAO is needed. As we think putrefaction products must appear and increase in the blood and ascites in SMAO, changes in the concentrations of ammonia, one of the putrefaction products, were measured in this study. Thirteen adult mongrel dogs were used for the in vitro experiment. The jejunum, ileum, and ascending colon were resected and incubated in saline. Changes in ammonia concentrations in the saline were examined at various incubation times. In the in vivo experiment, 11 mongrel dogs comprised the SMAO group and another 10 mongrel dogs comprised the control group. Changes in ammonia concentrations in the blood and ascites were examined in both groups. In the in vitro experiment, ammonia concentrations in the saline bath increased in all samples. It was highest in the sample from around the ascending colon, and lowest from around the jejunum. However, at the end of experiment, this difference became insignificant. In the in vivo experiment, ammonia concentrations in samples of the blood increased early and significantly in the SMAO group, compared with the control group. Ammonia concentrations in samples of the ascites also increased significantly. The in vitro experiment showed that ammonia leaked from the ischemic intestines, and secondarily, a large amount of ammonia was produced from intestinal putrefaction. The in vivo experiment revealed that the ammonia level in the blood could be used as a good early indicator of acute mesenteric ischemia.

Ammonia↗
PubMed1995

Pulsatile total artificial heart using a reversible rotary pump.

A pump circuit was assembled and examined for use as an implantable artificial heart. The circuit consisted of a gear pump and 4 artificial heart valves. Mitral and pulmonary arterial valves were placed at the inflow port of the pump, and aortic and tricuspid valves were placed at the outflow port. The mitral and the tricuspid valves were connected to each reservoir at 10 mm Hg, and the aortic and the pulmonary arterial valves were connected to the head tanks at 80 and 20 mm Hg, respectively. The pump discharged pulsatile flows into both systemic and pulmonary arteries alternately by switching the direction of rotation periodically. Because the rated discharge was 1.7 L/min for the gear pump used, the measured flow rate was 0.8-0.75 L/min at a heart rate of 60-110 bpm.

Aortic Valve↗
PubMed1995

Hemolysis and heat generation in six different types of centrifugal blood pumps.

What the most causative factor affecting hemolysis is still controversial. To resolve this problem, we investigated the relationship between hemolysis and heat generation in six types of centrifugal blood pumps (Bio-Pump, Delphin, Capiox, Nikkiso, Isoflow, and Toyobo). The analyzed parameters were index of hemolysis in fresh goat blood, pumping performance, and heat generation in a thermally isolated mock circuit. These parameters were analyzed at a flow rate of 5 L/min by changing the pressure head (100 mm Hg and 500 mm Hg). At 500 mm Hg of pressure head, the Bio-Pump needed the highest rotation number and showed the highest hemolytic rate and heat generation. The index of hemolysis is well correlated to heat generation (r2 = 0.721). Heat may originate from the motor by conduction, hydraulic energy loss, and mechanical friction between the shaft and seal. We strongly suspect that hemolysis was caused by a factor such as mechanical friction which generates heat locally.

Animals↗
PubMed1994

A flow visualization study of the NCVC centrifugal blood pump.

A compact centrifugal pump, NCVC-1, has an open-type impeller with 6 curved vanes, and it is characterized by no shaft and no seal. A tunnel is placed in the center of the impeller-rotor assembly to irrigate the back space behind the rotor. To evaluate the flow, we performed 3 visualization methods: tracer, oil film, and injection streak line method. The flow, observed by the tracer method in NCVC-1, indicated little turbulence along vanes. A volute chamber proved effective to reduce vortex formation in the outlet. Oil film pattern revealed no flow separation on vanes at 5 L/min. Washout flow behind the rotor is essential to prevent thrombus formation and was shown as inward spiral flow without any stagnation. These data suggested that a combination of visualization techniques was useful to analyze various flow conditions, and the NCVC-1 has excellent flow characteristics with little turbulence and little flow stagnation, which must be beneficial to low hemolysis and high antithrombogenicity.

Heart-Assist Devices↗
PubMed1992

[The usefulness of the emergency hepatobiliary scintigraphy to rule out acute cholecystitis--43 patients report].

We studied emergency hepatobiliary scintigraphy in the 43 patients to rule out acute cholecystitis. After injection of 185-222 MBq (5-6 mCi) of 99mTc-EHIDA or 99mTc-HIDA, serial static scintigraphic images were obtained up to 7 hours in maximum. Of 43 patients in this study, 20 had a normal scan and finally in all of them cholecystitis was ruled out. Of the 43 patients, 14 had an abnormal scan (nonvisualized gall bladder). In 10 of them the diagnosis of acute cholecystitis was confirmed after emergency cholecystectomy. The other 9 patients of 43 had an incomplete scan mainly due to liver dysfunction. Four of them had acute cholecystitis in the cholecystectomy. These results indicate that acute cholecystitis can be excluded by the findings of gall bladder visualization in hepatobiliary scintigram. We concluded that emergency hepatobiliary scintigraphy is very useful to rule out acute cholecystitis.

Acute Disease↗
PubMed1992

[A case report of primary cardiac lymphoma presented with marked cardiac accumulation of 67Ga-citrate].

A case of primary malignant lymphoma of the heart is reported. The patient who was a 67-year old male presented with dyspnea on exertion. The chest X-ray film showed an enlarged cardiac silhouette. UCG showed massive pericardial effusion and a mass in the right atrium. Although pathological confirmation was failed in the cardiac biopsy, malignant cardiac tumor was strongly suspected by a gallium scintigraphy, which showed marked accumulation in the heart. After irradiation therapy the cardiac tumor diminished in size and the cardiac 67Ga-citrate accumulation also disappeared. Multiple skin metastases, however, were soon noted, and a subsequent skin biopsy confirmed the diagnosis of malignant lymphoma. He died within 11 months in spite of systemic chemotherapy. Primary cardiac lymphoma is extremely rare, but this case suggested the cardiac mass with positive gallium scintigraphy have a possibility of cardiac lymphoma.

Aged↗
PubMedDate not supplied

Lipopolysaccharide induces expression of genes encoding pro-inflammatory cytokines and the elastin-degrading enzyme, cathepsin S, in human cervical smooth-muscle cells.

OBJECTIVE: Vaginal and amniotic infection with gram-negative bacteria is associated with preterm birth. We previously reported that human cervical smooth-muscle cells (CSMC) respond to pro-inflammatory cytokines by expressing enzymes that degrade the extracellular matrix. Our objective was to characterize the effects of lipopolysaccharide (LPS) from Escherichia coli (E coli), Bacteroides fragilis, (B frag)and Fusobacterium nucleatum (F nuc)on the expression of pro-inflammatory cytokines and the elastin-degrading enzyme, cathepsin S, in human CSMC. METHODS: Human CSMC were exposed to LPS and the expression of mRNAs encoding pro-inflammatory cytokines and cathepsin S, and selected matrix metalloproteinases (MMPs) was analyzed by Northern blotting. The effect of cytokine-neutralizing antibodies on LPS-induced cathepsin S mRNA expression also was determined. RESULTS: E coli LPS increased expression of cathepsin S 12.5-fold after 12 hours; MMP-1 and MMP-3 mRNAs also were increased 2.9- and 3.5-fold, respectively. Tumor necrosis factor (TNF)-alpha, interleukin (IL-1)alpha, and IL-1beta mRNAs were markedly up-regulated after 3 hours of LPS treatment. B frag and F nuc LPS also induced TNF-alpha and cathepsin S mRNAs. E coli LPS caused a sevenfold increase in TNF-alpha secretion after 5 to 8 hours. Antihuman TNF-alpha monoclonal antibody, but not a monoclonal antibody to the low-density lipoprotein receptor, reduced the LPS-induced increase in cathepsin S mRNA by 27%, whereas neutralizing antibodies against IL-1alpha and IL-1beta did not suppress the response. Human CSMC were shown to express the toll-like receptor (TLR-2) and TLR-4 genes, which mediate the action of LPS. TLR-2 mRNA was up-regulated by TNF-alpha. CONCLUSION: CSMC respond to LPS with increased expression of pro-inflammatory cytokines and cathepsin S. Increases in cathepsin S mRNA result only in part from the rapid induction of TNF-alpha gene expression. TNF-alpha may also augment the CSMC response to LPS by increasing expression of the LPS signaling receptor, TLR-2, which probably directly mediates LPS action. These observations provide a mechanism by which gram-negative bacteria can precipitate cervical changes associated with preterm birth.

Cathepsins↗