Glucose and Insulin Response to Peritoneal Dialysis Fluid in Diabetic and Nondiabetic Peritoneal Dialysis Patients

A postprandial increase in blood glucose in peritoneal dialysis (PD) patients with diabetes was observed in our previous study using continuous blood glucose monitoring. The response was observed in diabetic but not in nondiabetic PD patients. In addition, the response was reduced when patients used icodextrin; glucose absorbed from the peritoneum was responsible for the postprandial increase in blood glucose. Because our PD patients often change their PD fluid before meals, the present study aimed to determine the blood glucose and insulin responses to PD fluid. The 26 patients who agreed to participate in the study protocol [16 with diabetes (12 men, 4 women; 11 receiving insulin; 5 being controlled with oral antidiabetic drugs; average duration from diagnosis with diabetes: 16.4 ± 11 years); 10 without diabetes (4 men, 6 women)] had an average age of 60.5 ± 13.0 years. Average PD vintage was 578.7 ± 352.9 days. Blood samples were taken during a peritoneal equilibration test (PET) with 2.5% glucose solution at baseline and at 0.5, 2, and 4 hours. Levels of blood glucose and insulin were analyzed. A rapid increase in blood glucose (peak at 0.5 hours, 23.5 ± 22.2 mg/dL increase from baseline) was observed in nondiabetic patients. A delayed but higher peak response was observed in diabetic patients (peak at 1 hour, 54.9 ± 38.3 mg/dL increase from baseline). Peak response of insulin occurred at 0.5 hours in nondiabetic patients; in diabetic patients it occurred at 2 hours. No differences in the average insulin level during the PET were observed in the two groups (nondiabetic: 35.3 ± 15.6 μU/mL; diabetic: 38.9 ± 7.6 μU/mL). The study results suggest that a delayed insulin response after a PD fluid exchange could participate in the exaggerated postprandial increase in blood glucose in diabetic PD patients, particularly when the PD fluid exchange is performed before food intake.

Diurnal variations of blood glucose by continuous blood glucose monitoring in peritoneal dialysis patients with diabetes

Exaggerated postprandial increase in blood glucose has been postulated to be associated with cardiovascular injury. The concentration of blood glucose is altered by glucose absorption from peritoneal dialysis (PD) fluids. In PD patients, we used continuous blood glucose monitoring (CGM) to analyze diurnal variations in blood glucose. Diurnal blood glucose was determined in 10 diabetic PD patients who used CGM (iPro2: Medtronic, Northridge, CA, U.S.A.) for 3 days. Blood glucose concentrations before and after glycemic control were monitored in 5 patients. Correlations between CGM parameters [standard deviation of blood glucose (SDG)], peritoneal function [dialysate-to-plasma ratio of creatinine (D/P Cr) and end-to-initial dialysate (D/D0) glucose], 24-hour peritoneal glucose absorption, and glycemic index were determined. In 5 patients, CGM was performed again after adjustments to antidiabetic drugs. A large diurnal variation, especially at night, was observed in this patient cohort. No correlation of HbA1c with mean blood glucose concentration was observed. Although SDG had no association with 24-hour peritoneal glucose absorption, it did show an association with D/P Cr and D/D0 glucose. The SDG was significantly lower after treatment with a dipeptidyl peptidase IV inhibitor or an increase in insulin dose. Results of the present study indicate that diurnal variations in glucose depend on the speed of peritoneal glucose absorption rather than the net glucose absorption.

Beneficial role of tolvaptan in the control of body fluids without reductions in residual renal function in patients undergoing peritoneal dialysis

The V2 receptor antagonist tolvaptan has been approved for volume control in heart-failure patients in Japan. Tolvaptan increases renal blood flow, and so the present study was designed to ascertain whether tolvaptan could be a useful diuretic for volume control without reducing residual renal function (RRF) in peritoneal dialysis (PD) patients. Tolvaptan was administered in 15 PD patients (15 mg daily). Urine volume, body weight, and blood pressure were monitored Urinary excretion of urea nitrogen Na+, the osmolality of plasma and urine, and peritoneal and renal Kt/V were analyzed before and after tolvaptan treatment. In 11 of 15 patients, urine volume increased to more than 400 mL daily. A significant increase in diluted urine was observed, as indicated by a reduction in the specific gravity or osmolality of urine (or both). Urinary excretion of urea nitrogen, and Na+ was significantly increased Increases in renal Kt/V were observed, but peritoneal Kt/V was unchanged. Singnificant increase in creatinine clearance was also observed These data suggest that tolvaptan not only stimulates water diuresis, but also natriuresis, without reducing RRF in PD patients. Hence, tolvaptan could be a beneficial tool for the control of body fluid and maintenance of RRF in PD patients.

[Early malignant pleural mesothelioma; report of a case]

We report a case who had undergone operation of very early malignant pleural mesothelioma (MPM). A 58-year-old woman admitted to first visited hospital because of pleural effusion of the right side. She received a diagnosis of epithelial type MPM which had been confirmed from a pleural biopsy spacemen obtained by thoracoscopy under local anesthesia. An abnormal change of the pleura could not be detected on chest X-ray and thoracic computed tomography (CT) scan after chest drainage. She was referred to our hospital for surgery, and was undergone an extrapleural pneumonectomy followed by postoperative treatment with cisplatin puls gemcitabine. Pathologically, the disease was diagnosed as stage IA based on the classification of International Mesothelioma Interest Group (IMIG). There is a no evidence of the relapse 9 months after the operation. An early diagnosis of the MPM is very difficult. The thoracoscope with local anesthesia was very effective for early diagnose of a MPM.

[Bronchoplasty and pulmonary arterioplasty for treatment of lung cancer]

OBJECTIVE

We evaluated the outcomes of bronchoplasty (BP) and pulmonary arterioplasty (PAP) for treatment of patients with lung cancer.

SUBJECTS

We studied 33 patients who underwent BP and/or PAP over the previous 7 years at our institution.

METHODS

A telescope procedure was utilized for anastomosis of a tubular excision performed in the bronchus. One patient received induction chemoradiotherapy, in whom the anastomosis section was covered with an intercostal muscle flap to assure anastomosis completion, then PAP was performed under heparinization.

RESULTS

BP including a sleeve resection was performed in 15 patients, while that with a wedge resection and partial side wall resection was performed in 7 and 1 patient, respectively. PAP was performed in 18 patients, and a combination of BP and PAP was used in 8. The seam was incomplete in 2 patients and stenosis was recognized in the anastomosis section in 1. No local recurrence at the anastomosis site was seen in any of the 33 cases. The survival rate for patients who underwent BP was similar to that of those who underwent a standard resection for primary lung cancer.

CONCLUSION

Our results indicate that BP and PAP are safe and useful surgical procedures for patients with lung cancer.

[Uncommon procedure in tracheoplasty; thyrotracheal anastomosis and carinoplasty]

Both thyrotracheal anastomosis and carinoplasty are relative rare procedure in routine clinic. We reported each 2 cases of thyrotracheal anastomosis and carinoplasty in 51 cases of tracheobronchoplasty. Thyrotracheal anastomosis with partial cricoidectomy was performed in patients with subglottic stenosis for postintubation stenosis and thyroid cancer using suprahyoid release. Each case need re-intubation after surgery. Montage carinoplasty was performed in 2 patients with advanced lung cancer. Right upper lobe was end-to-side anastomosed to trachea in 1 case, and right basal segment was to left main bronchus in another. It was important both diameter in bronchus and mobilization of the residual lung for this procedure.

[Primary thyrotracheal anastomosis for subglottic stenosis with tracheostomy]

A case of 42-year-old man with postintubation subglottic stenosis underwent primary thyrotracheal anastomosis. Since trachea had been incised longitudinally for previous tracheostomy, tracheal resection came to be longer. Therefore, we had to anastomose the incised trachea with thyroid cartilage even after the suprahyoid release. After the operation, he suffered from the tracheal collapse at the incised portion of the trachea One week after intubation, tracheal patency was achieved. We recommend horizontal incision for tracheostomy in patient with subglottic stenosis, when the following surgical approach is considered.

[Extended sleeve lobectomy including carinaplasty for locally advanced lung cancer]

Because pneumonectomy causes a high-risk of perioperative mortality and morbidity, we have tried extended sleeve lobectomy (ESL) for patients with locally advanced lung cancer. The purpose of this study is to analyze the risk of complications and local relapses of ESL. Twelve patients underwent ESL, one-lobe and segment resection for 7, bi-lobe resection for 4, and bi-lobe and segment resection for 1. There was no hospital death. Two of 12 patients (17%) had an anastomosis complication. One (8%) had a staple line relapse. We conclude that ESL is a practicable technique for locally advanced lung cancer to avoid pneumonectomy.

Effects of antiplatelet agents on pulmonary haemodynamic response to fMLP in endotoxin primed rats

BACKGROUND

The interaction between neutrophils and platelets may be important in the modulation of pulmonary haemodynamics under systemic inflammatory conditions. A study was undertaken to examine whether antiplatelet agents inhibit platelet-neutrophil adherence and ameliorate the pulmonary haemodynamic response to fMLP by inhibiting thromboxane release in endotoxin primed lungs. fMLP stimulates neutrophils but not platelets; however, thromboxane synthesis in neutrophils is very low.

METHODS

Rats were pretreated with either cilostazol (300 mg/kg) or aspirin (50 mg/kg) before endotoxin priming (5 mg/kg). Platelets in the lung were identified by fluorescent immunohistochemistry. Platelet-neutrophil adherence was analysed by flow cytometry of the lung vascular flush. The effect of fMLP (10(-6) M) on thromboxane release, lung weight (an indicator of pulmonary vasoconstriction), and lung filtration coefficient was determined in an isolated lung system perfused at a constant pressure difference.

RESULTS

Endotoxin induced platelet accumulation and platelet-neutrophil adherence in the lung capillary were completely inhibited by cilostazol and aspirin while neutrophil recruitment was not affected. The fMLP challenge caused a significant increase in thromboxane B2 levels in endotoxin primed lungs. The fMLP induced decrease in lung weight was enhanced by endotoxin priming (from -4.9 to -63.9 mg, 95% CI of mean difference -99.5 to -10.5 mg, p<0.05). The fMLP induced increase in the lung filtration coefficient was also enhanced by endotoxin priming (from 0.63 to 2.40 mg/min/cm H2O/g, 95% CI of mean difference 1.17 to 2.37 mg/min/cm H2O/g, p<0.05). Treatment with cilostazol and aspirin completely inhibited the enhanced pulmonary haemodynamic response to fMLP.

CONCLUSION

The neutrophil-platelet interaction is of critical importance in the modulation of pulmonary haemodynamics via thromboxane.

[New surgical technique of pulmonary segmentectomy by ultrasonic scalpel and absorbable sealing materials]

We developed new surgical technique of pulmonary segmentectomy by ultrasonic scalpel to sever intersegmental pulmonary tissue and absorbable sealing materials to cover the cut surface of lung. This method is expected to preserve more anatomical lung volume than the segmentectomy with surgical stapler. Two cases of post surgical recurrent lung cancer, 3 cases of pulmonary metastasis and 4 cases of primary lung cancer were applied this technique to preserve function. Among 3 materials examined, best result was obtained with polyglycolic acid felt (PGAF:Neoveil). PGAF is a very soft and thin (0.15 mm depth) new absorbable material that is able to closely adhere to irregular sections of the lung with fibrin glue and effectively seals air leakage. Mean chest drainage period after surgery in 6 cases with PGAF was 3.3 days. Excellent lung expansion was obtained immediately after the surgery and PGAF was disappeared completely on chest CT within 1 year. Although the possible superiority of this method is suggested in the present study, further comparative study is necessary to clarify the advantage of this new technique.

[The prevention and measures to complication of video-assisted thoracoscopic surgery for lung cancer patients]

Video-assisted thoracoscopic surgery (VATS) for patient with lung cancer is seemed to be more genetic in future. It is because of small wound, little ache and short hospitalization. However, dissection of lymph-nodes is necessary since it is lung cancer. Because the thoracoscopic lobectomy is performed in the limited space, troubles those we cannot predict can happen. So surgical techniques of to prevent troubles are important. And this is the first step to avoid postoperative complication. It is necessary that to grasps a state of the patient and not to leave perioperative troubles.

Visual results and complications of temporal incision phacoemulsification performed with the non-dominant left hand by junior ophthalmologists

AIMS

To assess the results of temporal incision phacoemulsification and aspiration performed with dominant and non-dominant hand of ophthalmology trainees.

METHODS

Retrospective analysis were made of 203 surgeries with dominant hand and 207 with non-dominant by five trainees at two institutions. Trainees sat at the patient's head, manipulating instruments with the dominant right hand for the right eye, and the non-dominant left hand for the left eye.

RESULTS

Vitreous loss occurred in 12 (5.9%) of 203 dominant operated eyes and seven (3.4%) of 207 non-dominant operated eyes. The rate of endothelial cell loss was 6.1% (9.8%) in dominant and 7.4% (12.4%) in non-dominant. Mean ultrasound time were 1.81 (0.70) minutes in dominant and 1.78 (0.78) minutes in non-dominant. One trainee showed statistically significant excesses in incidence of vitreous loss in dominant operated eyes (8.7%, p=0.0270), and one showed statistically significant prolongation of the operation in nondominant operated eyes (26.3 minutes, p=0.0315). In all other trainees, all parameters had no difference in both sides.

CONCLUSIONS

Ophthalmology trainees could successfully learn the technique with both hands. The authors consider that the skill of the non-dominant hand may be knowledge based and that surgeons avoid mistakes by mental efforts.

[Metachronous lung cancer: indication and outcome]

Although lobectomy is the standard surgical treatment for primary lung cancer, it is unclear whether lobectomy will be benefit for patients with metachronous lung cancer. The purpose of this study is to evaluate the difference of benefit between lobectomy and limited resection at second lung resection. Forty-eight patients, who had already undergone lobectomy due to primary lung cancer, undergoing second lobectomy (n = 30) or limited resection (n = 18) for metachronous lung cancer were investigated. The over-all 5-year survival rate of second operation was 51.9%. Although there was no significant difference of 5-year survival rates between lobectomy and limited resection, 50.4% and 49.4%, respectively, lobectomy for T1N0 subset prolonged the survival compared to limited resection, 5-year survival rates, 69.6% and 31.7%, respectively. However, lobectomy resulted in more postoperative complications and less preservation of lung function. Lobectomy should be considered the surgical procedure of choice for patients with metachronous T1N0 lung cancer when lung function is preserved.

[18F] labeled diacylglycerol analogue as a potential agent to trace myocardial phosphoinositide metabolism

Phosphoinositide metabolism plays an important role in cardiac pathophysiology. To investigate whether [18F]diacylglycerol could be used to trace myocardial phosphoinositide metabolism, lipids were extracted from rat myocardium after the injection. 1-[8-[18F]fluorooctanoyl]-2-palmitoylglycerol and 1-[8-[18F]fluoropalmitoyl]-2-palmitoylglycerol were predominantly metabolized to phosphatidylethanolamine and triacylglycerol, respectively. The radioactivity incorporated into phosphoinositide metabolism was 51, 44, 32, and 30% 3, 5, 10, and 30 minutes after the injection of 1-[4-[18F]fluorobutyryl]-2-palmitoylglycerol, respectively. 1-[4-[18F]fluorobutyryl]-2-palmitoylglycerol might be a potential tracer to evaluate myocardial phosphoinositide metabolism early after the injection.

Combined resection of distal aortic arch for T4N0 non-small-cell lung cancer with aortic arch invasion

Three men age: 39-51 years (mean: 43.3 years) with T4N0 lung cancer infiltrating the distal aortic arch underwent combined resection of the left upper lobe, distal aortic arch, and left subclavian artery using partial extracorponeal circulation. Selective cerebral perfusion was used in 2. One underwent induction therapy (CDDP + VP - 16 x 2 + radiation 30 Gy), and all underwent adjuvant therapy. No postoperative complications or postoperative death occurred. Average ICU stay was 2.3 days. All patients are alive without local recurrence. Two were disease-free 37 and 26 months after surgery, and 1 had adrenal gland metastasis 8 months after surgery. Extended resection of the aortic arch in lung cancer is thus feasible and worthwhile in patients with T4N0 non-small-cell lung cancer.

Isolated unilateral absence of a pulmonary artery: influence of systemic circulation on alveolar capillary vessels

We report a case of isolated unilateral absence of a pulmonary artery. The first clinical symptom that was manifested in the patient was recurrent hemoptysis, and subsequent angiography revealed that the main pulmonary artery was absent in the right lung, which was being fed only from the systemic circulation. Right pneumonectomy was performed, and neither the main pulmonary artery nor its remnant was detected in the resected right lung. Histologically, there were many muscular vessels in the resected lung, with intimal proliferation, or with plexiform-like lesions. The alveolar septum was moderately thickened and alveolar capillary vessels were dilated. We examined the alveolar capillary endothelial cells of the resected lung for immunoreactivity to thrombomodulin (TM) and von Willebrand factor (vWF). The endothelial cells were negative for TM and positive for vWF, while in the normal lung control group, these cells were positive for TM and negative for vWF. We considered that the hemodynamics of the systemic circulation in the resected lung caused the alteration of immunohistochemical characteristics in alveolar capillary endothelial cells.

[Reevaluation of bronchoplasty for central-type lung cancer]

The outcome, anastomotic complications, and recurrence rate after bronchoplasty carried out in 198 patients with bronchogenic carcinoma in our institutions were evaluated retrospectively. The outcome of bronchoplasty was reasonable (5-year survival rate of 58%), but that of patients with adenocarcinoma was poor (5-year survival rate of 13%) because of their advanced stage and less complete resection. The complications of anastomosis occurred in 8.2% after bronchoplasty. Postoperative pneumonia significantly increased the risk of complications. There was no difference in the incidence of complications between patients who received end-to-end and telescope-type anastomosis. Local recurrence at the anastomosis occurred in 4.9% who underwent bronchoplasty, but in 28% who underwent carinal resection. Lymph node metastasis was a risk factor for local recurrence. Twenty patients with early superficial squamous cell carcinoma in the central bronchus were treated with photodynamic therapy without local recurrence. This new modality may be of benefit to selected patients.

Generation of oxidative stress contributes to the development of pulmonary hypertension induced by hypoxia

Chronic hypoxia causes pulmonary hypertension and right ventricular hypertrophy associated with pulmonary vascular remodeling. Because hypoxia might promote generation of oxidative stress in vivo, we hypothesized that oxidative stress may play a role in the hypoxia-induced cardiopulmonary changes and examined the effect of treatment with the antioxidant N-acetylcysteine (NAC) in rats. NAC reduced hypoxia-induced cardiopulmonary alterations at 3 wk of hypoxia. Lung phosphatidylcholine hydroperoxide (PCOOH) increased at days 1 and 7 of the hypoxic exposure, and NAC attenuated the increase in lung PCOOH. Lung xanthine oxidase (XO) activity was elevated from day 1 through day 21, especially during the initial 3 days of the hypoxic exposure. The XO inhibitor allopurinol significantly inhibited the hypoxia-induced increase in lung PCOOH and pulmonary hypertension, and allopurinol treatment only for the initial 3 days also reduced the hypoxia-induced right ventricular hypertrophy and pulmonary vascular thickening. These results suggest that oxidative stress produced by activated XO in the induction phase of hypoxic exposure contributes to the development of chronic hypoxic pulmonary hypertension.

[Establishment of a reference interval for highly sensitive CRP by exclusion of individuals with abnormal values in related laboratory tests]

In November, 1999, U.S. Food and Drug Administration approved a highly sensitive CRP(hs-CRP) assay that could assist medical doctors to predict the risk of cardiovascular accidents. Many doctors are now interested in the assay and trying to elucidate the relationship between serum CRP levels and cardiovascular diseases. In the past, it was difficult to establish a valid reference interval of serum CRP because of the poor analytical sensitivity and difficulty in sampling reference individuals. We have established a reference interval of serum CRP for the hs-CRP assay(Dade Behring). The study population consisted of 7,224 individuals(21-81 years old) who received a regular medical check-up. Potentially abnormal samples were excluded, depending on the results of other laboratory tests related to serum CRP variation. The upper limit of the reference interval was 0.15 mg/dl. The serum CRP was higher in smokers than in non-smokers, especially in men.

Experience with fatal interstitial pneumonia after operation for lung cancer

BACKGROUND

The number of patients with lung cancer is increasing. This study was undertaken to realize the probability, fate and management of acute fatal postoperative complications. Since interstitial pneumonia was one of the most fatal postoperative complications, to know its incidence and fate is very important.

METHODS

A total of 2667 patients who underwent thoracotomy caused by malignant tumors during the past 17 years were reviewed and studied. We performed investigations on medical records, chest X-rays, whole-body CT films, operative records and pathological specimens for all inpatients.

RESULTS

Nineteen patients died in hospital 30 days after thoracotomy (operative death). Nine patients died in hospital more than 31 days after thoracotomy (hospital death). Eight cases out of 28 patients (operative and hospital deaths) developed and finally died by interstitial pneumonia. Each case was treated with steroids, neutrophil-elastase inhibitor, and/or immunosuppressive agents. These patients could not be selected by any preoperative laboratory examination, such as preoperative pulmonary function tests, serum biochemistry tests, and chest X-ray or CT films. Interstitial pneumonia as a complication of postoperative stage, was fatal and once developed, it was very difficult to save their lives.

CONCLUSIONS

Since we reported the cases who died from acute postoperative complications, especially interstitial pneumonia, we could not present effective management. However, in this report, several therapeutic trials that may solve the problems of acute postoperative interstitial pneumonia were proposed.

Effect of Antioxidants on Radical-initiated Peroxidation of Retinal Homogenate

Purpose: To compare the effect of antioxidants on radical-initiated peroxidation of retinal homogenate.Methods: Lipid peroxides in bovine retinal homogenate were induced by 5 mM FeNO(3) (Fe), 25 mM 2, 2'-azobis(2, 4'-dimethylvaleronitrile) (lipid-soluble, AMVN) or 50 mM 2, 2'-azobis (2-amidinoprpane) dihydrochloride (water-soluble, AAPH) and the preventive effects of antioxidants were measured. Phosphatidylcholine hydroperoxide (PC-OOH) was analyzed with high performance liquid chromatography (HPLC) as the endpoint biomarker.Results and Conclusion: Troglitazone, an oral hypoglycemic agent, inhibited PC-OOH production by Fe and AMVN. Therefore, it may be effective for protecting against oxidative stress on the inner surface plasma membranes and subcellular organelle. Quercetin has radical scavenging effects on both sides of the membrane, because it prevents PC-OOH production by AMVN or AAPH. These results demonstrate the usefulness of an in vitro screening test that can accurately and rapidly determine the capacity of an antioxidant against lipid peroxidation or oxidative stress. (Jpn Ophthalmol Soc 104:466-70, 2000)

Lysyl oxidase and MMP-2 expression in dehydroepiandrosterone-induced polycystic ovary in rats

Polycystic ovary syndrome (PCOS) is characterized by cystogenesis; however, the cause of this cystogenesis is unknown. At ovulation, preovulatory collagenolytic activities in the ovarian follicles increase and various proteinases are needed to degrade the tissues surrounding the follicles. To clarify the roles of enzymes in collagen degradation of the follicular wall of polycystic ovary (PCO) in relation to the cystogenesis, we examined expression of lysyl oxidase (LOX), which initiates cross-link formation of the collagen and elastin in the extracellular matrix, and expression of matrix metalloproteinases (MMPs) in ovaries of model rats with PCO induced by dehydroepiandrosterone (DHEA) compared with MMP expression in control rats. DHEA treatment increased LOX mRNA expression to more than three times the control value (P: < 0.01). MMP-2 mRNA expression in control rats was threefold greater than that in the DHEA-induced group (P: < 0.05). Expression of both latent and active forms of MMP-2 in controls was more than twice that in the DHEA-induced group (P: < 0.05) as shown by Western blotting, and expression of the active form of MMP-2 was also twice as high in the controls as in the DHEA-treated group (P: < 0.05) as shown by zymography. Our results suggest that depression of MMP-2 activity and increased LOX expression may be one of the causes of the cystogenesis of PCO.

Visualization of myocardial phosphoinositide turnover with 1-[1-(11)C]-butyryl-2-palmitoyl-rac-glycerol in rats with myocardial infarction

Phosphoinositide turnover mediates the signaling of angiotensin II, which plays a pivotal role in ventricular remodeling after myocardial infarction (MI). We tested the hypothesis that phosphoinositide turnover can be visualized by 1-[1 -(11)C]butyryl-2-palmitoyl-rac-glycerol (11C-DAG) in both infarcted and noninfarcted myocardium after MI in rats.

METHODS

Rats received an injection of 11C-DAG 7 d after left coronary artery ligation, and myocardial lipids were extracted from both infarcted and noninfarcted areas of myocardium (n = 3). Metabolites of 11C-DAG were determined by thin-layer chromatography. Quantitative autoradiography of hearts was performed to visualize myocardial phosphoinositide turnover in rats that received an injection of 11C-DAG 1 d (n = 3) and 7 d (n = 5) after MI and 7 d after a sham operation (n = 3). Quantitative autoradiography with 201TlCl was also performed to evaluate myocardial blood flow in rats 7 d after MI (n = 3). Cells occupying the infarcted myocardium were identified by immunohistochemistry.

RESULTS

The radioactivity incorporated into the intermediates of phosphoinositide turnover was predominant in both the infarcted (67.1% +/- 5.2% of the total activity) and the noninfarcted (57.4% +/- 3.2%) myocardium. 11C-DAG radioactivity in the infarcted region normalized to that in the noninfarcted region was 1.09 +/- 0.04 in rats 7 d after MI, which was significantly higher than that in rats 1 d after MI (0.38 +/- 0.03, P < 0.001). 201Tl radioactivity in the infarcted region normalized to that in the noninfarcted region was only 0.19 +/- 0.01 7 d after MI. 11C-DAG radioactivity in the noninfarcted region normalized to that in the right ventricular free wall tended to be increased in rats 1 and 7 d after MI compared with the sham-operated rats; the differences, however, were not statistically significant (1.30 +/- 0.15, 1.20 +/- 0.07, and 1.13 +/- 0.02, respectively). Immunohistochemistry revealed that abundant fibroblasts, myofibroblasts, and macrophages occupied the infarcted myocardium 7 d after MI, but the cellularity was low during the first day after MI.

CONCLUSION

These data suggest that 11C-DAG may be useful for visualizing regions with activated phosphoinositide turnover after MI. Because wound healing and fibrogenic processes are important factors of ventricular remodeling, 11C-DAG and PET may offer new information benefiting patient management after MI.

Relationship between microsatellite instability and telomere shortening in colorectal cancer

PURPOSE

Two pathways have been proposed for the development of colorectal cancers: loss of heterozygosity and replication error. Colorectal cancers arising through the replication error pathway, like most hereditary nonpolyposis colorectal cancers, show microsatellite instability. It has been also reported that telomere shortening frequently occurs in colorectal cancers and that telomerase is often activated strongly in them. The aim of this study was to examine whether any relationships can be found among microsatellite instability, telomere length, and telomerase activity in colorectal cancers.

METHODS

Genomic DNA was extracted from 55 invasive cancers and corresponding normal mucosas. Five microsatellite loci were analyzed by polymerase chain reaction. Telomere length was examined by Southern blot analysis. Telomerase activity was assayed by telomeric repeat amplification protocol with minor modifications.

RESULTS

Microsatellite instability was found in 8 (14.5 percent) of 55 tumors, and all of them showed short telomeres. Furthermore, four high-frequency microsatellite instability tumors that showed microsatellite instability at more than two loci exhibited remarkably short telomeres. The microsatellite instability correlated significantly with frequency of telomere shortening (P = 0.0183; Fisher's exact probability test), but not with strength of telomerase activity.

CONCLUSION

The relationship identified by this study between microsatellite instability and telomere shortening might suggest some association between the DNA mismatch repair system and the telomere maintenance mechanism in colorectal cancers.

[Effect of antioxidants on radical-initiated peroxidation of retinal homogenate]

PURPOSE

To compare the effect of antioxidants on radical-initiated peroxidation of retinal homogenate.

METHODS

Lipid peroxides in bovine retinal homogenate were induced by 5 mM FeNO3 (Fe), 25 mM 2, 2'-azobis(2,4'-dimethylvaleronitrile) (lipid-soluble, AMVN) or 50 mM 2,2'-azobis (2-amidinoprpane) dihydrochloride (water-soluble, AAPH) and the preventive effects of antioxidants were measured. Phosphatidylcholine hydroperoxide (PC-OOH) was analyzed with high performance liquid chromatography (HPLC) as the endpoint biomarker.

RESULTS AND CONCLUSION

Troglitazone, an oral hypoglycemic agent, inhibited PC-OOH production by Fe and AMVN. Therefore, it may be effective for protecting against oxidative stress on the inner surface plasma membranes and subcellular organelle. Quercetin has radical scavenging effects on both sides of the membrane, because it prevents PC-OOH production by AMVN or AAPH. These results demonstrate the usefulness of an in vitro screening test that can accurately and rapidly determine the capacity of an antioxidant against lipid peroxidation or oxidative stress.

Long-term right ventricular volume overload increases myocardial fluorodeoxyglucose uptake in the interventricular septum in patients with atrial septal defect

BACKGROUND

Several studies have shown that long-term right ventricular (RV) overload in animal models alters myocardial energy substrate metabolism. However, whether long-term RV volume overload alters this metabolism in the human is unclear.

METHODS AND RESULTS

We performed positron emission tomography with [(18)F]fluorodeoxyglucose (FDG) and single-photon emission tomography (SPECT) with [(201)Tl]TlCl (Tl) and [(123)I]15-(p-iodophenyl)-3-R,S-methylpentadecanoic acid (BMIPP) in 11 patients with atrial septal defect (ASD) and 11 control subjects. In the FDG study, we calculated myocardial metabolic rate of glucose (MMR) in interventricular septum (IVS) and left ventricular (LV) free wall. MMR was significantly increased in IVS compared with LV free wall in the ASD patients (420+/-35 versus 333+/-32 mol x kg(-1) x min(-1); P<0.05) but not in the control group (347+/-27 versus 357+/-25 mol x kg(-1) x min(-1)). In both ASD and control groups, SPECT count was not significantly different between IVS and LV free wall in Tl (ASD, 160+/-11 versus 177+/-12; control, 141+/-12 versus 157+/-14 counts per 15 minutes) and BMIPP studies (ASD, 203+/-14 versus 212+/-18; control, 162+/-16 versus 176+/-16 counts per 15 minutes). MMR in the IVS/LV free wall ratio in the ASD group significantly correlated with indices related to RV volume overload.

CONCLUSIONS

Given the assumption that long-term RV volume overload did not affect the lumped constant, the present study suggests that, unlike myocardial perfusion or fatty acid analogue uptake, myocardial glucose utilization in IVS relative to LV free wall is increased in relation to long-term RV volume overload in patients with ASD.

Quantitation of macrophage migration inhibitory factor (MIF) using the one-step sandwich enzyme immunosorbent assay: elevated serum MIF concentrations in patients with autoimmune diseases and identification of MIF in erythrocytes

We raised monoclonal antibodies against human macrophage migration inhibitory factor (MIF), and developed a one-step sandwich enzyme-linked immunosorbent assay (ELISA) method highly specific for human MIF. The ELISA system utilizes a solid phase monoclonal antibody as a capture antibody and a horseradish peroxidase-conjugated monoclonal antibody as a detector antibody. We used this ELISA method to evaluate the serum level of MIF in 240 healthy volunteers (140 males and 100 females). We found no significant difference in MIF concentration with respect to age. A significant difference was found with respect to sex, with the mean value (+/- SD) for male subjects of 5.3+/-2.3, and that for female subjects of 4.6+/-2.3 ng/ml (p<0.05). We next measured the serum MIF contents of patients with autoimmune diseases, and found that MIF levels were significantly elevated in patients with systemic lupus erythematosus and rheumatoid arthritis, 20.0+/-11.0 ng/ml and 21. 7+/-11.2 ng/ml, respectively. Using anti-MIF antibody-immobilized sepharose column chromatography, we discovered for the first time that MIF was present in erythrocytes. Taken together these results suggest that MIF plays a major role in autoimmune diseases and, moreover, potentially induces various patho-logical outcomes in cases of hemolytic disorders.

Regional and temporal profiles of phorbol 12,13-dibutyrate binding after myocardial infarction in rats: effects of captopril treatment

Phosphoinositide turnover and protein kinase C (PKC) mediate the signaling of angiotensin II, which plays a pivotal role in ventricular remodeling after myocardial infarction (MI). To determine whether PKC is activated after MI, rat hearts after MI were subjected to in vitro quantitative autoradiography with [3H]phorbol 12,13-dibutyrate (PDBu), which is highly selective for PKC. [3H]PDBu binding in the infarcted area increased significantly compared with the non-infarcted region 7 and 21 days after MI, but not 1 and 3 days and 10 months after MI. [3H]PDBu binding in the noninfarcted area was similar to that in the sham-operated rats. Immunohistochemical analysis revealed that abundant macrophages (7 days after MI), fibroblasts, and myofibroblasts (7 and 21 days after MI) occupied the infarcted region. To investigate whether myocardial [3H]PDBu binding is affected by captopril, hearts were subjected to in vitro autoradiography with [3H]PDBu after 1- or 3-week captopril treatment or no treatment. Captopril treatment significantly suppressed [3H]PDBu binding in the infarcted area 3 weeks after MI, but not 1 week after MI nor in the noninfarcted areas. These results suggest that PKC is upregulated during the healing and fibrogenic process after MI and that captopril treatment suppresses the upregulation in the infarcted area.

Telomere shortening and the clinicopathologic characteristics of human colorectal carcinomas

BACKGROUND

It has been reported that shortening of telomeres and strong activation of telomerase occur frequently in colorectal carcinomas. In the current study, the authors examined the correlations between the telomere length of colorectal carcinomas and their clinicopathologic characteristics as well as the activity of telomerase to clarify whether telomere length might represent the biologic behavior of tumors and the mode of tumor development.

METHODS

Telomere length was examined by Southern blot analysis in 61 invasive colorectal carcinomas and corresponding normal mucosas. Telomerase activity was assayed by the telomeric repeat amplification protocol with minor modifications.

RESULTS

Shortening of the telomere was detected in 38 (62.3%) and elongation in 3 (4. 9%) of the 61 carcinomas. The telomere shortening occurred more frequently in nonulcerating polypoid carcinomas than in ulcerating carcinomas (P = 0.0373) and also occurred more frequently in ascending colon carcinomas than in sigmoid colon or rectal carcinomas (P = 0.0259 and P = 0.0407, respectively). However, no significant correlation was found between the activity of telomerase and the length of telomere.

CONCLUSIONS

The results of this study indicate that telomere length may represent the biologic behavior of individual tumors and possibly the mode of development of colorectal carcinomas.

Genetic polymorphism of CYP2D6 in the Japanese population

The frequencies of CYP2D6 mutations in a Japanese population were investigated. Individuals were classified into three groups: control individuals, cancer patients and Parkinsonians. Genotyping for CYP2D6*3, CYP2D6*4 and CYP2D6*18 was carried out using the polymerase chain reaction, and that for CYP2D6*5 was also carried out using XbaI restriction fragment length polymorphism. The frequencies of the CYP2D6*3, CYP2D6*4, CYP2D6*5 and CYP2D6*18 mutant alleles were 0%, 0.77%, 4.10% and 0.53% in more than 256 Japanese control individuals, respectively. Based on these data, the population frequency of the CYP2D6 poor metabolizer phenotype was estimated to be 0.29%. The distribution of the four mutated alleles was not significantly different between control individuals and cancer patients or Parkinsonians.

Superoxide anion mediates pulmonary vascular permeability caused by neutrophils in cardiopulmonary bypass

During cardiopulmonary bypass (CPB), neutrophils (PMNs) may be stimulated by shear stress which could contribute to the pulmonary injury that occurs after CPB. To elucidate whether mechanically stimulated PMNs increase pulmonary vascular permeability, measured as the pulmonary filtration coefficient (K) and pulmonary vascular resistance, and to elucidate whether superoxide anion mediates this increase, we assessed the effects of stimulated and unstimulated PMNs, and of superoxide dismutase (SOD) on K and resistance in isolated perfused lungs from Sprague-Dawley rats. PMNs were stimulated by gentle agitation in a glass vial for 10 s. Lungs perfused with the stimulated PMNs, being the stimulated group (n = 6), elicited a 5-fold increase in the filtration coefficient compared with lungs perfused with unstimulated cells, being the unstimulated group (n = 6). This increase in filtration was completely blocked by the preincubation of stimulated PMNs with CD18 monoclonal antibody, being the Ab group (n = 6), and also by superoxide dismutase, being the SOD group (n = 6). Pulmonary vascular resistance was not increased by stimulated PMNs, and the accumulation of stimulated PMNs was not blocked by SOD. These findings suggest that stimulated PMNs increase K and that superoxide anion may injure the pulmonary vascular endothelial cells.

In vitro testing of antioxidants and biochemical end-points in bovine retinal tissue

Lipid peroxidation in aliquots of bovine retina (without rod outer segments, ROS), purified ROS and retinal pigment epithelium (RPE) was initiated with 5 mM ferric iron and 80 mM ADP. After 30 min of oxidation at 37 degrees C, the concentration of thiobarbituric-acid-reacting substances (TBARS) which approximates lipid hydroperoxide (LHP), increased in the ROS from 2.0 +/- 3.6 to 90.2 +/- 34.5 nmol malondialdehyde (MDA)/mg protein and in the RPE from 0.54 +/- 0.2 to 51.5 +/- 15.8 nmol MDA/mg protein. Sixteen lipid and aqueous antioxidants (AOX) from natural or synthetic sources, including five flavonoids, were evaluated for their ability to inhibit the oxidative reaction. Palm-oil-derived vitamin E showed significant protection in retina, ROS and RPE (64, 68 and 74%), respectively. Of the flavonoids tested, good protection in the retina was found at 10(-5) M for epigallocatechin gallate (50%) and at 50 ng/ml for pycnogenol (61%) and catechin (52%). When catechin and palm oil vitamin E, catechin and coenzyme Q(10) or coenzyme Q(10) and pycnogenol were combined, the individual effect was enhanced. TBARS as an indirect measure of LHP level and hemoglobin-methylene blue determination for direct LHP were used as alternative end-point determinations of lipid peroxidation. These measure different aspects of AOX reactions. The results demonstrate the usefulness of an in vitro model system that can rapidly and accurately determine the capacity of a single AOX against lipid peroxidation or be used to show synergistic efficacy.

Detection of three genetic polymorphisms in the 5'-flanking region and intron 1 of human CYP1A2 in the Japanese population

Interindividual variability of the activity of CYP1A2 may be expected to affect cancer susceptibility, since the enzyme is capable of activating several carcinogens. In the present study, we found three new polymorphisms in the 5'-flanking region (CYPIA2/B) and intron 1 (CYPIA2/C and CYP1A2/D) of CYP1A2 in Japanese by using polymerase chain reaction-single strand conformation polymorphism. We developed methods to detect these polymorphisms by polymerase chain reaction-restriction fragment length polymorphism and performed a population study (159 subjects) to estimate the frequencies of the alleles. The frequencies of the CYP1A2/A (adenine), CYP1A2/B (thymine-deleted), CYP1A2/C (guanine) and CYP1A2/D (adenine) variants were 21.1, 42.0, 8.2 and 61.3%, respectively. The results of family study supported the idea that these CYP1A2 genotypes are inherited with an autosomal codominant transmission.