Biomedical subjects

M Tobe

Publications and source records attributed to M Tobe.

At least 37 records · Page 2Linked to original sources

PubMed1994

[Changes in luminal diameter of internal thoracic arteries five years after coronary artery bypass grafting].

Five years after coronary artery bypass grafting, 23 internal thoracic arteries (ITAs) were reexamined angiographically, and their luminal diameters were compared with those of one month after the operation. Proximal diameter, just below the subclavian artery, and distal diameter, just above the anstomosis, were measured. One month after surgery, these were 2.38 +/- 0.48 mm and 1.69 +/- 0.39 mm, respectively. After five years, the proximal diameter had not changed significantly (2.48 +/- 0.47 mm), but the distal diameter had increased to 1.96 +/- 0.58 mm (p < 0.05). Especially when there was no competitive flow with the ITA, the distal diameter showed a marked increase from 1.80 +/- 0.35 mm to 2.27 +/- 0.42 mm (p < 0.01). Twelve ITAs were grafted to coronary arteries having less than critical stenosis, and five of them showed distal narrowing or so-called string sign after five years. This seemed to be a form or physiological atrophy resulting from competitive flow, and the patients had no anginal pain in spite of their poor ITA runoff. When coronary artery stenosis is less than 75%, a choice is difficult between an ITA or a saphenous vein graft. We think that the graft must be selected considering the possibility of stenosis progression, if the jeopardized area is important for the patient. An ITA graft would be advisable in such cases.

Aged↗

PubMed1994

[Re-coronary artery bypass grafting for anomalous origin of left coronary artery from pulmonary artery (Bland-White-Garland syndrome) after operation in infancy: a case of 18-year follow-up].

Anomalous origin of the left coronary artery from the pulmonary artery is a very rare congenital malformation. Re-coronary artery bypass grafting was performed in a 18-year-old man who had received coronary artery reconstruction with a homologous saphenous vein (from his mother) at 7-months old. After the first operation, clinical course was uneventful, but the patient became symptomatic because of effort angina at age 15. The electrocardiogram showed abnormal ST segments in Lead V2-5 and abnormal T waves in Lead V5-6. Coronary arteriography revealed that saphenous vein graft was occluded. The left internal thoracic artery (LITA) was anastomosed to the left anterior descending artery and a two coronary system was established. Postoperative angiography revealed that LITA was patent, and relief of angina was obtained.

Adolescent↗

PubMed1994

[Delayed sternal closure for life-threatening massive bleeding during re-open heart surgery].

Delayed sternal closure (DSC) was used for 4 patients undergoing various cardiac reoperations to control perioperative hemorrhage. DSC was performed 48-72 hours later. All patients left the hospital alive and in good condition. The only recognized complication was an abscess formation around the bleeding area, which was successfully treated with systemic antibiotics. The remaining 3 patients manifested no infections. In two of these patients, hemodynamic instability was continued because of right ventricular outflow tract obstruction by compression of the packs which were left over the bleeding area. The function of coagulation of the blood was recovered except prothrombin time (PT) at the time of definitive closure of the chest. Recovery of the function of coagulation was useful in deciding the timing of DSC than hemodynamic state.

Aged↗

PubMed1994

[Surgical treatment of active infective endocarditis].

From January, 1978, through December, 1990, surgical treatment for active infective endocarditis was performed in 11 patients. There were 8 men and 3 women who ranged in age from 19 to 54 years with a mean age of 38.8 years. Two patients had ventricular septal defects and 1 patient had rheumatic valve disease. In all patients, the infecting organism was isolated from blood, including streptococcus in 7, staphylococcus in 2, and gram-negative rods in 2. The indication for operation at the active phase was uncontrolled infection in 7 and progressive heart failure in 4. The operation was performed at 7 to 150 days with a mean of 53 days after diagnosis. Operative findings showed vegetations in all cases and perforations of the valve in 6. There were no operative deaths. Perioperative complications developed in 5, whose indication for operation was uncontrolled infection. Complications consisted of 1 prosthetic valve endocarditis, 1 pulmonary suppuration, 1 ruptured mycotic aneurysm of the hepatic artery, 1 ruptured mycotic aneurysm of the popliteal artery, and 1 pyogenic spondylitis. All were successfully treated surgically or with antibiotic therapy. There were no complications in patients whose indication for operation was progressive heart failure. We conclude that the risk of embolism is high in patients undergoing surgery at the active phase of infective endocarditis because of uncontrolled infection; thus, such patients should be carefully monitored for emboli.

Adult↗

PubMed1994

[An experimental study on congenital foot deformity--with reference to a local disturbance in the limb bud using the exo utero survival method].

Experimental studies on abnormal developments in mammalian embryos have been limited by an inaccessibility to the embryo for surgical manipulations. Here we have developed the exo utero survival method proposed by Muneoka et al. in 1986 to produce models of various hindlimb anomalies by cauterizing a portion of the hindlimb bud of the mouse embryo. A total of 500 mice were used. The treatment was performed on time-pregnant JCL/ICR mice at 10.5 to 12.5 days of gestation (plug day = day 0). Polydactyly occurred in the group treated with pre-axial cauterization at 10.5 to 11.0 days of gestation, and oligodactyly at 10.5 to 12.5 days of gestation. A same insult resulted in different deformities depending on the time of cauterization. Immediately after the cauterization, there was a cloudy area in the limb bud, but at 15 minutes to one hour later, it developed into a necrotic focus surrounded by hemorrhaging and hematoma. The duration of the existence of this hematoma was various. The hematoma occurred just beneath the mesenchymal tissue in the peripheral venous sinus and moved proximally at 24 to 48 hours after the cauterization, in the group treated after 11.5 days of gestation (not seen in the 12.5 days group). This fact was considered to support the progress zone and positional value theory proposed by Summerbell et al. in 1973. From this study, it was concluded that the occurrence of foot deformities such as polydactyly, oligodactyly and cleft foot would have been determined by the site, severity and time of the local insult as well as by the recoverability of the mesenchymal tissue.

Animals↗

PubMed1993

New strategies for oligonucleotide synthesis by use of 2-trimethylsilylethyl and 2-trimethylsilylethoxymethyl as the phosphate and 2'-hydroxyl protecting groups, respectively.

The 2-Trimethylsilylethyl (TSE) group was found to be useful as a protecting group for the internucleotidic phosphate in DNA synthesis. Oligodeoxyribonucleotides were synthesized in good yields by using phosphoramidite building blocks having the TSE group. In RNA synthesis, 2-trimethylsilylethoxymethyl (SEM) group was introduced as a new protecting group for the 2'-hydroxyl. Selective protection of this function with SEM-Cl was achieved in good yield by use of 3',5'-O-bis(tert-butyl)silanediyl ribonucleoside derivatives.

Hydroxylation↗

PubMed1993

[Unusual non-infective inflammatory responses around a collagen impregnated vascular prosthesis].

Causes of some complications such as pyrexia, fluid accumulation and unusual scar formation around the graft in "Hemashield" implantation were examined both in vivo and in vitro. In an animal study, the grafts were implanted in the thoracic descending aorta of 9 dogs, and were explanted at 2 weeks after implantation. Macroscopic evaluation of the explants revealed that the graft had no infection, but fluid accumulation and a thick scar layer formation were noticed in the pleural cavity and around the graft. Microscopical observations demonstrated that the impregnated collagen was almost absorbed and numerous plasma cells, lymphocytes and macrophages had infiltrated in the interstices of the Dacron fibers, but neither fibroblasts nor capillary blood vessels. Numerous erythrocyte were also noticed in the graft wall. In vivo experiment of the extract from Hemashield, endotoxin and/or (1-3) beta-D-glucan were detected by the special quantitative methods; Toxicolor and Endospecy. These results indicated that the graft had some contaminants which contained a certain amount of endotoxin, (1-3) beta-D-glucan, resulting in non-infective inflammatory responses around the graft.

Animals↗

PubMed1993

[External work of canine latissimus dorsi muscle after vascular delay].

The first purpose of this study was to estimate physiological performance of skeletal muscle for circulatory assist. External work in the form of linear dynamic contraction was studied in canine latissimus dorsi muscle (LDM). The second purpose was to relate the effect of vascular delay of the LDM to the physiological performance. The left LDM with vascular delay (VD) were compared to the right control LDM (CTR) without vascular delay. Simultaneous dynamic contraction of both VD and CTR LDM were studied under various settings of the preloads and the afterloads. Maximal external work per single contraction were 136 +/- 38 mJ in VD and 81 +/- 21 mJ in CTR. Maximal total work, which includes external work and preload work, were 578 +/- 195 mJ in VD and 407 +/- 146 mJ in CTR. Maximal fractional shortenings of the LDMs were 22.8 +/- 4.7% in VD and 17.5 +/- 2.6% in CTR. The maximal external work of VD was 81% of canine LV stroke work and 620% of canine RV stroke work. The maximal total work of VD was 340% of canine LV stroke work. The fractional shortenings, external work and total work of VD were higher than those of CTR under all loading conditions. The physiologic performance of canine LDM was improved after vascular delay.

Animals↗

PubMed1993

[The assessment of multiple coronary artery bypass with bilateral internal thoracic artery grafts].

From 1982 to March 1991, 68 patients underwent coronary artery bypass grafting (CABG) using bilateral internal thoracic arteries (ITA). There were 62 males (91.2%) and 6 females (8.8%) ranging from 33 to 74 years old (mean 58.5 +/- 9.2). Thirty four patients had old myocardial infarction (OMI) and left main trunk disease was seen in 8.5% of the patients. The number of grafts was 2 to 6 per patient with an average of 3.2 +/- 1.0. In bilateral ITA grafting the combinations of RITA to LAD and LITA to LCX were most frequently used. There were no operative deaths except for one death which occurred while at the hospital. The patency rates for the RITA and LITA were 98.3% and 96.7%, respectively. Postoperative complications included reexploration for bleeding and heart tamponade in 9 patients, and low output syndrome in 7 patients. The frequency of blood transfusion decreased with the use of cell saver. Routine bilateral ITA grafting for multiple CABG is considered safe, with the early patency being relatively better than with saphenous vein grafting.

Adult↗

PubMed1993

[Clinical assessment of cerebral infarction, complicated with aortic arch replacement under selective cerebral perfusion].

Since October 1984 to December 1992, 47 aortic arch replacements were performed under selective cerebral perfusion (SCP). Patient age ranged from 19 to 81 years, with an average of 60.2 years. Thirty one patients were male and 16 female. Twenty patients were diagnosed with dissecting aneurysms, 27 true aneurysms. The operative mortality was 14 out of 47 (29.8%) over all. The mortality of dissecting aneurysm related acuity that is 5 of 9 (55.6%) for patients in acute phase, against none in chronic. The operative mortality of true aneurysms was 6 out of 11 (54.5%) for patients who had emergency operation, against 3 out of 16 (18.8%) scheduled, extensive surgery. Cerebral disorders developed on 8 patients out of 44 (18.2%, except 3 operative deaths). The mortality rate of cerebral disorder was 6 out of 8 (75.0%). Six patients with true aneurysm had cerebral infarctions after the surgery. Two patients had already cerebral disorders in advance the surgery. The cause of cerebral infarction was resumed by atherosclerotic materials. Our operative results indicate that cerebral disorder subsequently affects the mortality of aortic arch replacement. For the prevention of cerebral infarction, we modified the method of SCP. We start the SCP at the initiation of total cardiopulmonary bypass, routinely associated to an aortic clamp and cardiac arrest under myocardial protective procedure that is the use of perfusion cooling (30 degrees C, monitored at the esophagus), topical cooling and cold Saint Thomas solution infused in the coronary arteries. When aortic arch replacement is done, we need to make sure a good restarting of the heart and a good recovery of the systemic circulation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

[Long-term results of closed mitral commissurotomy--comparative study of closed mitral commissurotomy (CMC), open mitral commissurotomy (OMC) and mitral valve replacement (MVR)].

As the technique of open heart surgery has improved, CMC has been abandoned in favor of OMC and MVR. We evaluated and compared the results of CMC, OMC and MVR. METHOD. Between 1965 and 1978, 141 patients with mitral stenosis (MS) underwent CMC, and late follow-up obtained in 117 (83%) of them (CMC group). Between 1980 and 1989, 72 patients and 37 patients underwent OMC (OMC group) and MVR (MVR group), respectively. Cumulative follow-up periods were 1982, 632 and 200 patient-years in the CMC, OMC and MVR groups, respectively. RESULTS. (1) Survival rate; In the CMC group there were 2 operative deaths due to severe mitral regurgitation (MR). There were 17 late deaths, due to reoperations in 4 patients, cerebral infarction in 4 patients, congestive heart failure in 3 patients, myocardial infarction in 2 patients and unknown causes in 4 patients. The survival rate was 95%, 91% and 86% at 5, 10 and 15 years, respectively, in the CMC group. In the OMC and MVR groups there was no death. (2) The event free rate was 89%, 79% and 58% at 5, 10 and 15 years, respectively, in the CMC group, 97% and 97% at 5 and 10 years in the OMC group, and 95% and 90% at 4 and 5 years in the MVR group. (3) Reoperations; In the CMC group of 40 patients (34%) required reoperations in an average of 10.4 years after the initial operation, due to re-MS in 22 patients, MR in 10 patients and MRS in the 8 patients. Reoperative findings consisted of clefts in the mitral leaflets in 7 patients. There were pulmonary hypertension in 15 patients and tricuspid regurgitation in 22 patients. Fourteen patients underwent tricuspid anuloplasty and one patient underwent a tricuspid valve replacement. In the OMC group one patient required a reoperation due to MR; in the MVR group one patient required a reoperation due to a thrombosed valve. CONCLUSION. In the CMC group the survival rate and the event free rate were lower, and the rate of reoperation was higher than in the other two groups.

Adult↗

PubMed1992

Combined Repeat Dose and Reproductive/Developmental Toxicity Screening Test (OECD): familiarization using cyclophosphamide.

A familiarization study was conducted on the "Combined Repeat Dose and Reproductive/Developmental Toxicity Screening Test (ReproTox)" proposed by the OECD. Cyclophosphamide (CP) at doses of 6.7, 4.5, 3, 2, and 0 mg/kg body wt was given daily by gavage to groups of 12 male and 12 female Sprague-Dawley rats. As a result, anemia and leukopenia were evident in treated males. The absolute and relative thymus and spleen weights were decreased in treated rats. Histopathologically, atrophy of the thymus, spleen, and bone marrow was observed. With respect to the reproductive/developmental toxicity, dose-dependent increases in postimplantation loss of fetuses and postnatal death were found in dams given CP. The body weight of pups treated with CP was significantly lowered in a dose-related manner. Thus the results demonstrated most of the known toxicological properties of CP, except the adverse effects on spermatogenesis and fertility. Therefore ReproTox can be considered as a useful screening test for assessing repeat dose and reproductive/developmental toxicity of existing chemicals of high production volume.

Animals↗

PubMed1992

Toxicities of microencapsulated tribromomethane, dibromochloromethane and bromodichloromethane administered in the diet to Wistar rats for one month.

The gelatin-starch syrup microencapsulation method was applied to subacute toxicity studies of tribromomethane (TBM), dibromochloromethane (DBCM) and bromodichloromethane (BDCM). Groups of Wistar rats (7 males and 7 females) both sexes were given diet containing microcapsules of each of these trihalomethanes (THMs) at the following concentrations: TBM, 0.068, 0.204 and 0.612% in males, and 0.072, 0.217 and 0.651% in females; DBCM, 0.020, 0.062 and 0.185% in males, and 0.038, 0.113 and 0.338% in females; BDCM, 0.024, 0.072 and 0.215% in males, and 0.024, 0.076 and 0.227% in females. Suppression of body weight gain was seen in each high-dose males fed TBM or BDCM and females fed DBCM or BDCM. Histopathologically, hepatic lesions such as vacuolization and swelling of liver cells were significantly noted in both sexes of all groups fed TBM, in both sexes of the middle- and high-dose groups fed DBCM, and in males of the high-dose group and in females of the middle- and high-dose groups fed BDCM. In addition, single cell necroses were observed in males and females fed DBCM and in males fed BDCM. Hepatic cord abnormalities were also noted in males of the high-dose group fed BDCM. Although no increases in serum transaminase activities (ASAT, ALAT) were evident in either sex fed any of the THMs, decreases in triglyceride content, cholinesterase and lactate dehydrogenase activity were observed. Renal lesions reported to occur in gavage studies were not found in the present feeding study. Lowest-observed-adverse-effect-level (LOAEL) of TBM and no-observed-adverse-effect-level (NOAEL) of DBCM and BDCM were determined to be 56.4 mg/kg, 18.3 mg/kg and 20.6 mg/kg, respectively, under the present experimental conditions.

Administration, Oral↗

PubMed1992

Toxicity studies of a synthetic antioxidant, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol) in rats. 1. Acute and subchronic toxicity.

The acute and subchronic toxicity studies on 2,2'-methylenebis (4-ethyl-6-tert-butylphenol) (MBEBP) were conducted using male and female Wistar rats. In acute toxicity test, the LD50 values were estimated to be greater than 10 g/kg BW by oral and intraperitoneal administration in each sex. In subchronic toxicity test, groups of 10 rats of each sex were fed a diet containing 0.2, 1.0 or 5.0% of MBEBP and examined at 4 and 12 weeks. Body weight gain was significantly depressed at doses of 1.0 and 5.0% in both sexes, but the depression in the 1.0% group was severer than that in the 5.0% group in males. Hematological analysis showed slight but significant decrease of hemoglobin in the 1.0 and 5.0% groups of both sexes. Urine analysis showed no remarkable changes in all treated rats of both sexes. In biochemical analysis of serum, decrease of triglyceride level and cholinesterase activity, and increase of amylase activity were observed in treated rats. Histopathologically, testicular atrophy and decrease of spermatogenesis were observed in male rats fed 1.0 or 5.0% MBEBP for 4 and 12 weeks and vacuolization of parathyroid gland cells was observed in female rats fed 1.0 and 5.0% MBEBP for 12 weeks. In subchronic test, the lowest observable adverse effect levels for MBEBP toxicity were estimated to be 171 mg/kg BW/day in male rats and 180 mg/kg BW/day in female rats.

Administration, Oral↗

PubMed1992

Chronic toxicity of microencapsulated bromodichloromethane administered in the diet to Wistar rats.

A chronic feeding study was carried out in Wistar rats using microencapsulated bromodichloromethane. The test substance was administered in the diet at doses of 0, 0.014, 0.055 and 0.22% for 24 months. Rats were sacrificed after 6, 12, 18 and 24 months of continuous dosing. The results showed a suppression of body weight gain in the 0.22% group for both males and females. Dose related changes were clearly observed in the liver with histopathological findings including fatty degeneration in the 0.014% or higher dose male groups, and fatty degeneration and granuloma in the 0.055 and 0.22% group females, as well as bile duct proliferation and cholangiofibrosis in the 0.22% group for both males and females. No significant differences in incidences or numbers of neoplastic changes were seen between control and any of the treatment groups. There were no dose-related non-neoplastic lesions in the kidneys of either sex. Lowest-observed-adverse-effect-level was determined to be 6.1 mg/kg/day under the present experimental conditions.

Animal Feed↗

PubMed1992

[Selection of graft materials in case of emergency coronary bypass surgery following failed angioplasty].

The clinical characteristics of selection of graft materials were analysed for patients undergoing emergency coronary artery bypass surgery (CABG) following failed coronary angioplasty (PTCA). Ten emergency CABGs were performed from January 1983 to December 1991. Perioperative variables and follow-up were compared to 18 patients undergoing elective CABG after PTCA. The emergency group had shorter operative time (p less than 0.01) and shorter bypass time (p less than 0.05). Moreover the emergency group had decreased use of the internal thoracic artery (ITA) (40% vs 94.4%, p less than 0.01). There was no use of bilateral ITAs in the emergency group. There was not significant difference in hospital mortality and medium term follow-up between two groups. In conclusion, emergency CABG carries a significantly less use of ITA graft than elective CABG although ITAs are superior to SVGs about long term patency rate. So it is desirable that arterial graft should be used under an appropriate selection at emergency operation.

Aged↗

PubMed1992

[Surgical repair of discrete subaortic stenosis complicated with prosthetic valve endocarditis--a case report].

A 46-year-old man was referred to our hospital because of prosthetic valve regurgitation. Eight years previously he had undergone aortic valve replacement because of aortic regurgitation due to infective endocarditis. At reoperation, we found prosthetic valve endocarditis and discrete subaortic stenosis. The obstructing fibrous tissue was resected and the aortic valve was replaced. Because discrete subaortic stenosis is usually located just below the aortic valve, the aortic valve cusps are liable to become thickened by the jet through the discrete stenosis and thus are vulnerable to infective endocarditis. It is pointed out that care must be taken not to overlook discrete subaortic stenosis in the presence of other associated cardiac disorders.

Aortic Valve↗

PubMed1992

[A case of reoperation of coarctation of the aorta 13 years after corrective surgery of coarctation of the aorta, ventricular septal defect and pulmonary hypertension in infancy].

A 13-year-old boy underwent corrective surgery of CoA + VSD + PH at 50-day. Vascular murmur and hypertension was present so that he was admitted to our hospital. Systemic pressure was 164/106 mmHg (right arm) and systolic blood pressure at right leg was 70 mmHg. The systolic pressure gradient was 94 mmHg. The intracardiac pressure was within normal limit and there was no shunt. And the stenosis of descending aorta was present at the distal of subclavian branch and that pressure gradient was 76 mmHg. The diagnosis was established recurrent coarctation and operation was performed. The recurrent coarctation was 8 mm in diameter and longitudinal incision was made and woven Dacron patch aortoplasty was done. Aortic cross clamping time was 43 minutes. Postoperative clinical course was smooth. At 4 weeks after aortography was performed and no appreciable stenosis of the descending aorta was revealed. The pressure gradient decreased from 76 mmHg to 11 mmHg.

Adolescent↗