Biological significance of enhanced mitochondrial ketogenesis during the early stages after 70% hepatectomy in rats

Ketogenic capacity of mitochondria from the remnant liver of 70% hepatectomized rats was studied in relation to mitochondrial phosphorylative activity. Ketogenic capacity increased to a maximum of 6.04 +/- 0.39 from 3.84 +/- 0.13 of control, with an enhancement of mitochondrial phosphorylative activity 6 hr after hepatectomy, and then decreased to normal levels within 24 hr. Adenylate energy charge, (ATP + 1/2ADP)/(ATP + ADP + AMP), of the remnant liver decreased to 0.825 +/- 0.006 as compared to 0.849 +/- 0.002 of control 6 hr after operation. At 12 hr, total ketone body concentrations of the arterial blood increased concomitant with a fall in ketone body ratio (acetoacetate/3-hydroxybutyrate) which reflects the decreased liver mitochondrial redox (NAD+/NADH) state. These findings suggest that an enhancement of mitochondrial fatty acid oxidation and ketogenesis occurs concomitant with an enhancement of mitochondrial phosphorylative activity in the remnant liver in response to a decreased energy charge after 70% hepatectomy.     

Thallium-201 SPECT depicts radiologically occult lung cancer.

A case of radiologically occult lung cancer is presented in which 201TI SPECT of the chest clearly delineated the involved area. A 66-yr-old man underwent chest screening examinations for asymptomatic smokers and presented a positive sputum cytology for lung cancer. Conventional chest x-ray, tomography of computed radiography, and a CT scan failed to locate the lesion in the lung. Thallium-201 SPECT, however, was successful in depicting the area of the involvement.     

Glucose consumption and rate constants for 18F-fluorodeoxyglucose in human gliomas.

To investigate the value of direct measurement of the rate constants by performing 18F-labeled fluorodeoxyglucose (FDG) studies of glucose consumption in human gliomas in vivo, a kinetic method with 3- and 4-parameter rate constant models for FDG uptake was used to analyze data from dynamic scans obtained by positron emission tomography after injection of FDG into 14 patients with glioma. The results were compared with those obtained by the autoradiographic method using 3- and 4-parameter rate constant models. There were no significant differences in the glucose consumption calculated by the four different methods both in the gliomas and in the contralateral intact cortex. It was found that the rate constant k4* could be neglected in calculation of glucose consumption in gliomas as well as in the contralateral intact cortex. The rate constant k3*, an index of hexokinase function, was higher in malignant gliomas than in benign gliomas and was close to that in the contralateral cortex. This study indicates that the 3-parameter autoradiographic method, which is the most common one used in clinical practice, is reliable for the calculation of glucose consumption in human gliomas. Furthermore, direct measurement of the regional rate constants for FDG by the kinetic method was found to be useful for evaluation of the biochemical and physiological characteristics of human gliomas in vivo.     

The results of an investigation of the various factors influencing the late patency ratio of coronary bypass grafting

The purpose of this communication was to find out the factors influencing the late patency ratio of coronary artery bypass grafts of 42 patients in our institution. The following results were obtained: 1. The size of the measured diameters of coronary arteries and the graft flow rates were correlated well to the late patency ratio (p less than 0.05). 2. The regular physical exercise trainings were significantly important to keep patent grafts (p less than 0.01). 3. In blood serum studies, serum uric acid levels were significantly lower (p less than 0.05), the average mean HDL cholesterol levels were much higher (p less than 0.001) and the ratio of total cholesterol to HDL cholesterol were significantly lower in the group with late patent grafts than with grafts occluded. Therefore, we found out the variables affecting graft patency ratio which were examined by a stepwise method were the diameter of the coronary artery, regular physical exercise training, the average of lower serum uric acid levels and higher HDL cholesterol levels. The multiple coefficient for these four variables was 0.562 (p less than 0.001) and the contribution was 31.6%. According to the base of this studies, we have concluded that postoperative regular physical exercise, low fat and restricted calorie intake were very important to keep the late patent grafts in long-term follow up period after coronary bypass surgery.     

Comparison of flow capacities of arterial and venous grafts for coronary artery bypass grafting: evaluation with exercise thallium-201 single-photon emission tomography

Stress thallium-201 tomography was performed to compare the flow capacities of arterial and saphenous vein grafts in patients with coronary artery bypass grafting (CABG). One hundred and seven consecutive patients (95 male and 12 female; mean age 58±9.1 years) underwent exercise-redistribution ²⁰¹Tl myocardial single-photon emission tomography 4–5 weeks after CABG. When a reversible perfusion defect was present in the area covered by a patent bypass graft, the flow capacity of the graft was defined as insufficient. Of all 285 grafts, 211 were considered as complete bypass. Reversible perfusion defects were present in 29 (27%) of 108 myocardial areas supplied by patent arterial grafts but in only 5 (5%) of 103 myocardial areas supplied by patent saphenous vein grafts (P<0.0001). In the LAD area reversible defects were observed in 22 of 82 areas covered by arterial grafts, in contrast to only 1 of 29 areas covered by venous grafts (P<0.01); in the RCA area reversible defects were observed in 7 of 17 and 4 of 41 areas respectively (P<0.01). There was no difference between the native coronary artery stenosis bypassed by patent arterial and venous grafts (88%±12% vs 86%±14% respectively, P=0.27). In conclusion, flow capacities during peak myocardial demand were more frequently insufficient in arterial bypass grafts than in saphenous vein grafts. Received 23 May and in revised form 7 August 1997     

Effects of bifemelane on the free fatty acid levels during ischemia

Using the four-vessel extracranial one staged occlusion model of adult Wistar rats, we analyzed quantitatively released free fatty acids during ischemia. Also have we analyzed the effect of bifemelane to reduce free fatty acid accumulation after the onset of ischemia. Bifemelane (15 mg/kg, 30 mg/kg) and saline as control were intraperitoneally administered to adult Wistar rat prior to 30 minutes of experimentally induced ischemia. The results obtained were analyzed by one or two way analysis of variance (ANOVA). Physiological variables (systemic arterial pressure, PaO2, PaCO2, pH) did not change significantly in all four experimental groups. Total free fatty acid levels (sum of 5 fatty acid) increased significantly after ischemia (30 minutes). Higher dose (30 mg/kg) of bifemelane administration significantly reduced total free fatty acid accumulation, though lower dose (15 mg/kg) did have no effect. Bifemelane (30 mg/kg) reduced significant accumulation in the amount of saturated and monounsaturated fatty acid (palmitic acid [16:0], stearic acid [18:0] and oleic acid [18:1]). Arachidonic (20:4) and docosahexaenoic (22:6) acid failed to show any effective reduction by bifemelane pre-treatment of lower nor higher dose. Bifemelane is supposed to have many pharmacological effects such as increase in cerebral blood flow, augmentation of glucose uptake, monoamine metabolism, cerebral vasodilatation and platelet antiaggregation. Free fatty acid accumulation is effectively suppressed by the higher dose of bifemelane administration. Although the exact mechanism are not clearly identified by the result obtained in this experiment, selective inhibition of accumulation in saturated and monounsaturated fatty acids by bifemelane pretreatment may be obtained by the improvement of energy metabolism, which may help to reacylation of fatty acid into phospholipid.     

Iron in the enameloid of perciform fish.

It is known that a high concentration of iron is deposited in the enameloid of some teleostean fish. Previously, Suga et al. (1989) pointed out that the iron concentration in the enameloid is related to the phylogeny of fish rather than to the feeding habits, according to the results of quantitative iron analyses on the teeth of marine teleost fish of the Tetraodontiformes. In the present study, in order for the previous idea to be verified, quantitative iron analysis was made with an electron microprobe on the enameloid of fish belonging to the Perciformes, which is the largest group of teleostean fish in the world and consists of both marine and freshwater species. The enameloid of all the fish examined (57 species) contained high iron concentrations ranging from 0.2% to 10.2% at the surface or middle layer, whereas that of an advanced suborder, Tetraodontoidei, of the Tetraodontiformes was very low in iron, at a level which could not be discriminated from the background value of the emission intensity. The distribution pattern of iron in the enameloid was classified into at least two types, namely, type A, in which a high iron concentration was observed mainly in the surface layer, and type B, in which iron was deposited throughout the entire layer, although there were differences in concentration. There were some differences in the concentration and distribution of iron in the enameloid for the families; for example, those of the Scaridae had a type A distribution, with about 0.2% iron only at the surface layer, whereas those of the Cichlidae, Centrarchidae, and Acanthuridae, which showed a type B distribution, contained iron ranging from 2.9% to 10.5% at the surface or middle layer of enameloid. Such differences seemed to be associated with the difference in timing of the commencement of the iron deposition into the developing enameloid, which is probably related to the phylogeny of fish. There was no evidence to support the idea that the iron concentration in the enameloid is associated with the feeding habits of fish, as proposed by previous investigators.     

Reconstructive surgery for supravalvular aortic stenosis after arterial switch operation for simple transposition in the early neonate

Recently, many papers have reported the development of severe pulmonary stenosis after an arterial switch operation (ASO) for the transposition of the great arteries (TGA) with intact ventricular septum (IVS) in the early neonate. However, supravalvular aortic stenosis after the same procedure is very uncommon. We experienced supravalvular aortic stenosis which developed gradually after successfully performing the Lecompte maneuver for TGA with IVS in a 6-day-old baby. We underwent Doty's extended aortoplasty in his 11th-month. We approached the aorta through the transection of the pulmonary trunk which was located just before the aorta. At the stenotic parts of the aorta, a discrete projection of cicatricial tissue was observed mainly at the posterior wall. The projection of the cicatricial tissue seemed to be induced as a consequence of the contraction of the aortic wall where a continuous suture was tied too tightly with non-absorbable suture materials. To prevent this complication after the Lecompte maneuver for TGA with IVS in the neonate, it is important to take care not to tie the suture too tightly and to use absorbable suture materials for construction of the aorta. There are the recommendations which we observed would prevent the post-operative complication of supravalvular aortic stenosis. As a final note, in repairing the supravalvular aortic stenosis, an approach through the transection of the pulmonary trunk was very useful.     

Myocardial perfusion and clearance of 99mTc teboroxime assessed by SPECT]

99mTc teboroxime is a new myocardial imaging agent that has characteristics of high accumulation in the heart and rapid clearance. We performed tomographic teboroxime study and compared the findings with that of 201Tl. Myocardial teboroxime clearance was calculated by dynamic single photon emission computed tomography (SPECT) using continuous repetitive rotation acquisition method. Teboroxime SPECT image was reconstructed by the three-minute data started from 4 minutes after injection. In 45 myocardial regions (15 patients), complete agreement between 201Tl and 99mTc teboroxime was obtained in 33 regions (73%), when the findings were classified as normal, ischemia and infarction. Significant delay in clearance was seen in the region of coronary stenosis (greater than or equal to 75%) compared with that in the control region (p = 0.0087 at rest, and p = 0.0385 at peak exercise by paired T test). Septum-to-lateral ratios of the clearance and myocardial initial count showed positive correlation (r = 0.743). Further clinical application of this radiopharmaceutical is expected as a new myocardial imaging agent.