Should the supplemental vein graft be anastomosed upstream or downstream of the internal thoracic artery (ITA) for ITA hypoperfusion?

BACKGROUND: This study was designed to compare internal thoracic artery (ITA) flow in different settings of supplemental vein grafting for ITA hypoperfusion. METHODS: Fourteen dogs each received two coronary bypass grafts to the circumflex artery (CFX), using left ITA and vein grafts, and then the proximal CFX was ligated. The animals were divided into two groups. G-I dogs receiving the vein graft proximally to the ITA graft and G-II receiving the vein distally. ITA flow was evaluated regarding 1) effects of competition from the vein graft, and 2) pharmacological or physiological effects on the ITA's contribution to distal perfusion. Flow is expressed as a mean (ml/min). RESULTS: ITA flow was 44.2+/-5.9 in G-I, and 45.7+/-6.5 in G-II (p=ns), when the vein graft was occluded. With a vein graft open, ITA flow decreased to 7.5+/-1.6 in G-I, and 6.8+/-1.8 in G-II (p=ns), and ITA's contribution to total perfusion requirements was 18% in G-I and 16% in G-II. Adenosine (0.2 mg/min/kg) increased the ITA flow in both groups, 18.4+/-3.2, and 16.3+/-3.8, respectively (p=ns), and ITA's contribution to distal perfusion was increased to 32% in G-I and 27% in G-II. In contrast, phenylephrine (0.003 mg/min/kg) decreased ITA flow and ITA's contribution to distal flow in both groups (6.1+/-1.1, 11% vs 6.2+/-1.4, 11%, p=ns), but increased vein flow significantly. Cardiac pacing (150 bpm) increased the ITA flow and ITA's contribution to distal perfusion equally in both groups (8.4+/-1.5, 16% vs 7.6+/-2.6, 15%, p=ns). CONCLUSIONS: Supplemental vein grafting, whether it is placed distally or proximally, limits ITA flow and ITA's contribution to distal perfusion both in the resting heart and during the increased myocardial oxygen demand.     

Suppressive effect of partially hydrolyzed guar gum on transitory diarrhea induced by ingestion of maltitol and lactitol in healthy humans

OBJECTIVES: To estimate the suppressive effect of partially hydrolyzed guar gum (PHGG) on transitory diarrhea induced by ingestion of a sufficient amount of maltitol or lactitol in female subjects. DESIGN: The first, the minimal dose level of maltitol and lactitol that would induce transitory diarrhea was estimated separately for each subject. Individual subject was administered a dose that increased by 5 g stepwise from 10 to 45 g until diarrhea was experienced. Thereafter, the suppressive effect on diarrhea was observed after each subject ingested a mixture of 5 g of PHGG and the minimal dose level of maltitol or lactitol. SETTING: Laboratory of Public Health Nutrition, Department of Nutrition and Health Sciences, Siebold University of Nagasaki. SUBJECTS: Thirty-four normal female subjects (21.3+/-0.9 years; 49.5+/-5.3 kg). MAIN OUTCOME MEASUREMENT: Incidence of diarrhea caused by the ingestion of maltitol or lactitol and the ratio of suppression achieved by adding PHGG for diarrhea. RESULTS: The ingestion of amounts up to 45 g of maltitol, diarrhea caused in 29 of 34 subjects (85.3%), whereas the ingestion of lactitol caused diarrhea in 100%. The diarrhea owing to maltitol was improved in 10 of 28 subjects by the addition of 5 g of PHGG to minimal dose-induced diarrhea, and that owing to lactitol was in seven of 19 subjects. Adding 10 g of PHGG strongly suppressed the diarrhea caused by maltitol, and the cumulative ratio was 82.1% (23/28). CONCLUSION: The transitory diarrhea caused by the ingestion of maltitol or lactitol was clearly suppressed by the addition of PHGG. These results strongly suggest that diarrhea caused by the ingestion of a sufficient amount of non-digestible sugar substitute can be suppressed by the addition of dietary fiber.     

A case of Standford type B aortic dissection involving a right-sided aortic arch with mirror-image branching and right-sided descending aorta

Isolated right aortic arch with mirror-image branching is a rare congenital anomaly. To date, no case has been reported for aortic dissection involving a right aortic arch with mirror-image branching. We report here on a case involving a 58-year-old man in whom expanding type B aortic dissection was demonstrated in the right aortic arch with mirror-image branching and a right descending aorta. The patient was successfully treated by interposition of a prosthetic graft via a right posterolateral thoracotomy approach. We also reviewed the literature.     

Impaired insulin secretion by diphenyleneiodium associated with perturbation of cytosolic Ca2+ dynamics in pancreatic beta-cells

Pancreatic islets express the superoxide-producing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system, but its role remains unknown. To address this, we studied the mechanisms of impaired insulin secretion induced by diphenyleneiodium (DPI), an NADPH oxidase inhibitor. We investigated the effects of DPI on glucose- and nonfuel-stimulated insulin secretion, islet glucose metabolism, and intracellular Ca2+ concentration ([Ca2+]i) dynamics in rat islets and beta-cell line RINm5F cells. DPI did not affect insulin secretion at 3.3 mm glucose but totally suppressed insulin secretion stimulated by 16.7 mm glucose (percentage of control, 9.2 +/- 1.2%; P <0.001). DPI also inhibited insulin release by high K+-induced membrane depolarization (percentage of control, 36.0 +/- 5.3%; P <0.01) and protein kinase C activation (percentage of control, 30.2 +/- 10.6% in the presence of extracellular Ca2+, P <0.01; percentage of control, 42.0 +/- 4.7% in the absence of extracellular Ca2+, P <0.01). However, DPI had no effect on mastoparan-induced insulin secretion at 3.3 and 16.7 mm glucose under Ca2+-free conditions. DPI significantly suppressed islet glucose oxidation and ATP content through its known inhibitory action on complex I in the mitochondrial respiratory chain. On the other hand, DPI altered [Ca2+]i dynamics in response to high glucose and membrane depolarization, and DPI per se dose-dependently increased [Ca2+]i. The DPI-induced [Ca2+]i rise was associated with a transient increase in insulin secretion and was attenuated by removal of extracellular Ca2+, by L-type voltage-dependent Ca2+ channel blockers, by mitochondrial inhibitors, or by addition of 0.1 or 1.0 microm H2O2 exogenously. Our results showed that DPI impairment of insulin secretion involved altered Ca2+ signaling, suggesting that NADPH oxidase may modulate Ca2+ signaling in beta-cells.     

Comparison of clinical, tumour-related and dosimetric factors in grade 0-1, grade 2 and grade 3 radiation pneumonitis after stereotactic body radiotherapy for lung tumours

Objective

The aim of this study was to investigate significant clinical, tumour-related and dosimetric factors among patients with grade 0–1, grade 2 and grade 3 radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT) for lung tumours.

Methods

Patients (n=128) with a total of 133 lung tumours treated with SBRT of 50 Gy in 5 fractions were analysed. RP was graded according to the Common Terminology Criteria for Adverse Events v.3.0. Significant factors were identified by univariate and multivariate analyses. Threshold dose–volume histograms (DVHs) were constructed to identify the incidence of RP.

Results

The median follow-up period was 12 months (range, 6–45 months). In univariate analyses, gender, operability, forced expiratory volume in 1 s (FEV1), internal target volume, lung volumes treated with doses >5–30 Gy (V5–30) and mean lung dose were significant factors differentiating between grade 0–1 and grade 2 RP, and V15–30 were significant factors differentiating between grade 2 and grade 3. However, no factors were significant between grade 0–1 and grade 3 RP. Multivariate analysis showed that female gender, high FEV1 and high V15 were significant factors differentiating between grade 0–1 and grade 2 RP. Threshold DVH curves were created based on ≤5% and ≤15% risk of grade 2 RP among patients with grade 0–2 RP.

Conclusions

Grade 0–2 RP was dose–volume dependent, and female gender and high FEV1 were significant predictive clinical factors for grade 2 RP among patients with grade 0–2 RP. However, incidences of V15–30 in grade 3 RP were significantly lower than those in grade 2 RP, and no significant clinical or tumour-related factors were found. Further studies are needed to identify the mechanism underlying the development of grade 3 RP after SBRT for lung tumours.Previously, we investigated the clinical and dosimetric factors that correlate with severe radiation pneumonitis (RP) in patients with lung tumours treated with stereotactic body radiotherapy (SBRT) [1]. We found that, among a variety of factors, only a short latent period was a significant correlate of severe RP.Other reports [2-6] have also analysed the clinical and dosimetric factors correlated with RP after SBRT. Various dosimetric factors were reported to significantly correlate with RP after SBRT, which included the mean dose in the ipsilateral lung, V7 and V10 by Kyas et al [2], normal tissue complication probability (NTCP) by Ricardi et al [3], lung volumes treated with doses higher than 2.5–50 Gy (V2.5–50) by Guckenberger et al [4], mean lung dose by Barriger et al [5] and contralateral V5 by Ong et al [6].We found a discrepancy in the significant clinical and dosimetric factors between the results of these five studies on low-grade RP [2-6] and our study on severe RP [1]. We speculated that the mechanism underlying the development of grade ≥3 RP might be different from that of grade 2 RP. Additionally, the treatment of grade ≥3 RP was much more critical than that of grade 2 RP. Most patients with grade ≥3 RP needed to be admitted to hospital and steroids or oxygen therapy were administered. By contrast, patients with grade 2 RP were simply followed up carefully without administration of medication as outpatients.In the present study, to ascertain this discrepancy, we analysed the clinical and dosimetric factors that correlated with RP after SBRT among patients with grade 0–1, grade 2 and grade 3 RP in the same sample of patients as that included in our previous study [1].     

Beneficial effects of coenzyme Q10 on impaired left ventricular performance in streptozotocin diabetic rats

Chronic effects of coenzyme Q10 (CoQ: 30 mg/kg/day for 12 weeks) on cardiac performance in streptozotocin (45 mg/kg) induced diabetic rats were examined. Cardiac performance was assessed using the isolated retrograde perfused isovolumically contracting heart model. Compared to age matched nondiabetic rats, decreases occurred in myocardial CoQ (25.8 +/- 3.3 vs. 31.9 +/- 2.7 micrograms/ml), AMP (0.9 +/- 0.7 vs. 2.0 +/- 0.4 micrograms/mg), Emax (37 +/- 14 vs. 80 +/- 38 mmHg/microliter/g), an index of myocardial contractility, and LV diastolic chamber stiffness constant k (0.68 +/- 0.13 vs. 1.31 +/- 0.59 g/microliter) in diabetic rats. Normalized left ventricular weight (2.97 +/- 0.23 vs. 2.51 +/- 0.21 mg/g) and volume (1.53 +/- 0.34 vs. 0.89 +/- 0.53 microliter/g) and time constant of left ventricular pressure fall, T (32.0 +/- 8.0 vs. 19.7 +/- 2.6 ms) increased in diabetes. In diabetic rats taking CoQ, myocardial CoQ (28.5 +/- 3.2 micrograms/ml) and AMP (2.1 +/- 1.7 micrograms/mg) were the same as control, and T (23.5 +/- 7.4 ms) was significantly shortened (mean +/- SD, p less than 0.05, p less than 0.01). To compensate for depressed myocardial contractility and relaxation, LV dilatation and increased LV mass occurred in diabetic rats. Exogenous CoQ increased myocardial CoQ content and improved myocardial relaxation in diabetic rats.     

Cerebral imaging by magnetic resonance imaging and single photon emission computed tomography in systemic lupus erythematosus with central nervous system involvement

OBJECTIVE: To assess the significance of magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) abnormalities in patients with systemic lupus erythematosus (SLE). METHODS: Forty-four patients with SLE were retrospectively analysed. Patients were classified into three groups [1 and 2: patients with central nervous system (CNS) manifestations before and after starting high-dose steroid therapy, respectively; 3: patients without CNS manifestations. MRI was performed in all 44 patients and SPECT in 31. RESULTS: Abnormal findings in MRI were found in 19 patients. MRI abnormalities were significantly more frequent in patients with CNS manifestations than in those without [71 vs 17%, odds ratio (OR) 11.9, confidence interval (CI) 2.8-49.9, P=0.0003]. After the initiation of steroid therapy, patients with CNS manifestations also had an increased frequency of abnormal MRI. No correlation was found between SPECT findings and CNS manifestations. However, patients with CNS manifestations after starting steroids showed a markedly increased frequency of abnormal MRI and SPECT compared with those without CNS manifestations (80 vs 7%; OR 56, CI 4.4-719, P=0.0003). The positive predictive value of abnormality in both techniques in developing CNS manifestations after starting steroids was 89%. CONCLUSION: MRI findings correlated with CNS manifestations in SLE. Where there is a high suspicion of CNS involvement, the combination of MRI and SPECT may be useful in predicting CNS manifestations after starting steroid therapy.     

Reconstruction of pulmonary artery with substitute valve--with special reference to size of conduit and valve

Operative risk factors and postoperative late results were evaluated in 26 patients undergoing pulmonary artery reconstruction with a substitute valve. Seventeen extracardiac conduits bearing a valve were used in 16 patients and an in situ pulmonary valve insertion was carried out in the other 10. The surgical results were influenced by complexity of the underlying cardiac lesions and pulmonary vascular status, with a high mortality rate in patients with several cardiac defects including single ventricle, asplenia syndrome, complete atrioventricular canal etc. The mortality rate was 6% in patients with an immediate post-repair Ppv/sv of less than 0.75 and 77.8% in those with a Ppv/sv over 0.75. Postoperative Ppv/sv was mainly regulated by valve area index and a close correlation was obtained for the regression equation Ppv/sv = 0.41/(VAI)2 + 0.36 (r = -0.61, p less than 0.05). To obtain excellent hemodynamics with a Ppv/sv of less than 0.50, valve area index should be over 1.7 cm2/M2, and to eliminate re-implantation of the conduit after reaching adulthood, the diameter of the conduit should be 18 mm or more and the valve size 23 A, or more when a SJM valve is used.