Sarcopenia-derived exosomal micro-RNA 16-5p exerts the cardio-repair disturbance via pro-apoptotic mechanism in myocardial infarction of mice

Background

Sarcopenia is a pathophysiological malfunction induced by skeletal muscle atrophy, and several studies reported an association between sarcopenia-induced cardiac cachexia and poor prognosis in heart disease. Since only a few established animal models are recently available, the underlying mechanism of disturbed cardiac repair accompanied with sarcopenia remains poorly understood.

Purpose

We hypothesized that specific microRNAs in sarcopenia-derived exosomes play crucial roles in disturbed cardiac repair with sarcopenia, and these microRNAs directly exacerbate cardiomyocyte injury following cardiac ischemia and reperfusion.

Methods

We developed a novel sarcopenia-induced cardiac repair disturbance mouse model that is induced by tail suspension (TS) 7 days after a 45-min coronary occlusion of cardiac ischemia and reperfusion (I/R). The reduction of the left ventricular ejection fraction (LVEF) after I/R was compared in mice with TS [I/R-TS(+), n=14] and without [I/R-TS(−), n=12] by echocardiography. To investigate the exosomal mechanism of cardiac repair disturbance, a comprehensive analysis of extracted exosomal microRNAs from mice serum was performed in the 2 groups at day 8. Then, we investigated the impact of the identified candidate microRNA in neonatal rat cardiomyocytes (NRVMs). After 4 days in primary culture, candidate microRNA was transfected into NRVMs under hypoxic culture conditions. TUNEL analysis and quantitative PCR analysis of apoptosis-related genes were performed on the NRVMs.

Results

At day 8 after I/R, the LVEF of I/R-TS(+) was not significantly ameliorated compared to that of I/R-TS(−) (ΔLVEF; 1.59±6.92 vs. 8.04±7.71% p=0.034). Four candidate microRNAs obtained from I/R mice serum were identified in the microRNA array analysis. The re-analysis of these candidate micro-RNAs using all I/R mice demonstrated that the level of mir-16-5p in I/R-TS(+) was raised by approximately nine-fold than that in I/R-TS(−) (9.67±13.35 vs. 0.99±1.41, p<0.05). Next, an in vitro experimental model using a microRNA mimic revealed that apoptosis in NRVMs was greatly enhanced by the transfection of a mir-16-5p mimic in hypoxic culture conditions (mir-16-5p vs. control = 5.77±2.84 vs. 1.72±0.55%, p<0.01). Furthermore, by qRT-PCR analysis, the expression of CASP3 and TRP53 were upregulated in NRVMs treated with a mir-16-5p mimic than in control NRVMs.

Conclusion

Myocardial I/R injury in sarcopenia ended in cardiac repair disturbance accompanying with the enhanced expression of exosomal-mir-16-5p. A pro-apoptotic effect of mir-16-5p may exacerbate myocardial I/R injury and thus can be a novel therapeutic target for cardiac repair disturbance in sarcopenia.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Japan Society for the Promotion of Science

P4144Pericyte-specific deletion of ninjurin1 induces abnormal vasa vasorum formation and persistent inflammation and enhances intimal hyperplasia of injured vasculature

Introduction

Atherosclerosis is fundamental pathological condition inducing severe ischemic diseases such as ischemic heart disease and stroke. New concept has been proposed that adventitial abnormalities including enhanced malformation of adventitial microvessel, vasa vasorum are associated with development and vulnerability of atherosclerotic plaque. However, the role of vasa vasorum malformation in vascular remodelling has not been fully clarified. We recently reported that Ninjurin1 (Ninj1) is critical adhesion molecule to associate pericytes (PCs) with endothelial (EC) tubes to form stabilized mature neovessels. The purpose of this study is to examine if formation of adventitial microvessels affects the vascular remodelling of injured vessels using PCs-specific Ninj1 deletion mouse model.

Methods and results

Deletion of Ninj1 gene in NG2-positive PCs was induced by tamoxifen (Tam)-treated NG2-CreER/Ninj1loxp mice (Ninj1KO, n=9). Tam-treated-NG2-CreER (n=4) or Tam-nontreated NG2-CreER/Ninj1loxp (n=5) mice were used as Control (Ct1 and Ct2 respectively). Femoral arteries were injured by insertion of coiled wire. After 4 weeks of surgery, blood vessels were stained by venous injection of FITC-lectin. Isolated femoral arteries were fixed with paraformaldehyde and decolorized with CUBIC reagent. Wire-mediated vessel injury induced intimal hyperplasia, as assessed by intima/media (I/M) ratio and accordingly grew microvessels in adventitia. Intimal hyperplasia in Ninj1KO were significantly enhanced compared to Controls. Although there was no significant difference in total length of adventitial microvessels among three groups, extravasation of FITC-lectin from adventitial microvessels were significantly enhanced in Ninj1KO. The number of infiltrated macrophages in adventitia were increased in Ninj1KO.

Conclusion

Deletion of Ninj1 in PCs contributes to formation of immature microvessels in adventitia of injured vasculature and to adventitial microbleeding, and subsequently enhances intimal hyperplasia. Ninj1 is an attractive target to normalize microvessels for anti-atherosclerotic therapy.

Roles of prostanoids in the pathogenesis of cardiovascular diseases

The roles of prostanoids in the pathogenesis of cardiovascular diseases and in the development of pathological conditions have been examined using mice lacking the individual, specific prostanoid receptor. Prostaglandin (PG) I2 protected the heart from ischemia-reperfusion injury in a model of acute myocardial infarction. In addition, PGI2 suppressed the development of pressure overload-induced cardiac hypertrophy. Aside from its potent vasodilatory action, PGI2 contributed critically to the development of renovascular hypertension via the activation of the renin-angiotensin-aldosterone system. Thromboxane (TX) A2 and PGF2alpha were found to be the mediators of inflammatory tachycardia under a systemic inflammatory condition induced by lipopolysaccharide. Under a septic condition leading to a vascular hypo-responsive state, TXA2 worked to maintain vascular tone by inhibiting the induction of inducible nitric oxide synthase in vascular smooth muscle cells. Mice lacking the PGE2 receptor subtype EP3 had a bleeding tendency and were resistant to thromboembolism, due to a defective activation of platelets. From these studies, the important and novel roles of prostanoids in the pathogenesis of cardiovascular diseases have been clarified.

A cardiac sodium channel mutation identified in Brugada syndrome associated with atrial standstill

Mutations in the cardiac Na+ channel gene SCN5A are responsible for multiple lethal ventricular arrhythmias including Brugada syndrome and congenital long QT syndrome. Here we report a case of Brugada syndrome with ST elevation in the right precordial and inferior leads accompanied by atrial standstill and spontaneous ventricular fibrillation. Atrial standstill and J wave elevation were provoked by procainamide. Genetic analysis revealed a missense mutation (R367H) in SCN5A. The resultant mutant Na+ channel was nonfunctional when expressed heterologously in Xenopus oocytes. Our study suggests that genetic defects in SCN5A may be associated with atrial standstill in combination with ventricular arrhythmias.

Combined diagnostic imaging for retroperitoneal schwannoma

Retroperitoneal tumors are occasionally encountered by gynecologists, and differential diagnosis from adnexal tumors is important, however, it is difficult in many cases. We report a case in which we preoperatively diagnosed a benign solid tumor in the retroperitoneum of the pelvic cavity on the basis of a variety of diagnostic images, including FDG-PET. Postoperative histological examination showed a benign schwannoma in the pelvis. We discuss the usefulness of FDG-PET combined with MRI and other diagnostic images as a means of differentiating between the characteristics of retroperitoneal tumors.

Prognostic predictive value of 18F-fluorodeoxyglucose positron emission tomography for patients with pancreatic cancer

18Fluorine-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) is a unique imaging diagnostic tool to evaluate glucose metabolism and hexokinase activity which may reflect the aggressiveness of a tumor. Thirty-seven patients with primary pancreatic cancer were evaluated with 18F-FDG-PET. Thirteen patients underwent resection for the pancreatic cancer and 24 patients had unresectable tumors. The standardized uptake values (SUV) of 18F-FDG in the primary tumors were calculated. No correlations were found between the SUV in the tumors and the metastatic status to the peritoneal/liver, TNM factors/stage, or resectability. The patients were divided into 2 groups with high and low SUV, with the cut-off value being 3.0 (median SUV value of 37 cases). No differences in the probability of survival were observed between the 2 groups in the patients with resectable tumors. However, in the patients with unresectable tumors, those in the high SUV group had a significantly shorter prognosis than those in the low SUV group. Moreover, a multivariate analysis of survival indicated that SUV is an independent prognostic factor for patients with unresectable pancreatic cancer.

A case of tuberculous peritonitis monitored by gallium-67 scintigraphy

An 18-year-old man was admitted to our hospital for further examination of fever of unknown origin and ascites. Ga-67 scintigraphy revealed diffuse increased uptake throughout the abdomen. He was diagnosed with tuberculous peritonitis and began the treatment for tuberculosis (rifampicin, 450 mg/day orally and isoniazid, 300 mg/day orally, and 0.75 g of streptomycin by intramuscular injection 2 times a week). One year after starting the treatment, Ga-67 scintigraphy revealed accumulation of radioactivity in the upper abdomen, but the diffuse accumulation in the abdomen decreased. A specimen obtained by tumor biopsy under ultrasonic guidance revealed a tuberculous granuloma. Percutaneous injection was performed in the tumor with 1.0 g of streptomycin. On Ga-67 scintigraphy performed 2 weeks after the injection of streptomycin, the accumulation of radioactivity in the upper abdomen had disappeared. These findings suggest that Ga-67 scintigraphy is useful for diagnosis and observation during treatment of tuberculous peritonitis.

Mesenteric desmoid with uptake on gallium-67 citrate scintigraphy

A 72-year-old man was hospitalized for further evaluation of a space-occupying lesion in the abdomen. Magnetic resonance imaging revealed a tumor 40 mm in diameter in the abdomen. Anterior Ga-67 citrate scintigraphy revealed a region of accumulation of radioactivity in the abdomen corresponding to the tumor. Mesenteric desmoid was diagnosed on the basis of histological findings for the excised tumor. These finding suggested that mesenteric desmoid may be one of the tumors which show high uptake of Ga-67.

Diagnostic usefulness of FDG PET for pancreatic mass lesions

The purpose of this study was to investigate the feasibility of [18F]2-deoxy-2-fluoro-D-glucose (FDG) positron emission tomography (PET) in patients with a pancreatic mass by comparing the results with those of X-ray computed tomography (CT) and magnetic resonance (MR) imaging.

METHODS

Eighty-six patients with pancreatic lesions, included 65 malignant tumors and 21 benign masses (55 masses were proven histologically and the others were diagnosed clinically), were studied. The diagnostic factors of CT and MR imaging were evaluated, and those of FDG PET were also evaluated for malignant and benign masses by visual interpretation and quantitative interpretation with the standardized uptake value (SUV) and SUVgluc which was designed to reduce the effects of a high blood sugar level. Visual interpretations were evaluated only in FDG PET images, and quantitative interpretations were evaluated by referring to CT and/or MR imaging. The correlation between SUV and the degree of histological differentiation in pancreatic ductal adenocarcinoma was investigated.

RESULTS

Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for CT imaging were 91, 62, 88, 68 and 84%, and for MR imaging 78, 70, 88, 54 and 76%, respectively. In visual interpretation of FDG PET images, the sensitivity, specificity, PPV, NPV and accuracy were 82, 81, 93, 59 and 81%, respectively. Significant differences between malignant and benign lesions existed in SUV and SUVgluc (p < 0.0001, each). With the cutoff value of SUV as 2.1 and SUVgluc as 2.2, the accuracy of diagnosis was maximal. With that cutoff value, the sensitivity, specificity, PPV, NPV and accuracy for SUV were 89, 76, 92, 70 and 86%, and for SUVgluc 91, 76, 92, 73 and 87%, respectively. The sensitivity and NPV of SUVgluc were higher than those of SUV, which suggests that SUVgluc may be more useful in reducing the number of overlooked malignant tumors. The specificity and PPV of FDG PET were superior to those of CT and MR imaging. There were no significant differences between the SUVs of moderately differentiated adenocarcinomas and those of well differentiated adenocarcinomas.

CONCLUSION

To improve the diagnostic procedure for classifying masses, FDG PET with not only SUV but also SUV corrected by the blood sugar level is required in addition to morphological diagnosis by CT and/or MR imaging.

Accessory spleen in the pelvis diagnosed by Tc-99m phytate scintigraphy

We report a 58-year-old woman with an accessory spleen in the left side of the pelvis. She visited our outpatient clinic complaining of lower abdominal discomfort. Abdominal ultrasonography revealed a tumor 4 cm in diameter in the left side of the pelvis. Color Doppler ultrasonography demonstrated plentiful pulsating blood flow. Magnetic resonance angiography revealed that the blood supply for the tumor was from a branch of the splenic artery. Scintigraphy with Tc-99m phytate revealed accumulation of radioactivity concordant with a mass in the left side of the pelvis, and the spleen was normally visualized. These findings suggested that this tumor was an accessory spleen, and the patient underwent no further invasive procedures.

A case of glucagonoma with high uptake on F-18 fluorodeoxyglucose positron emission tomography

Glucagonomas are relatively rare, and can be difficult to differentiate from other pancreatic tumors. A 62-year-old woman who had suffered from diabetes mellitus was hospitalized for further evaluation of a space-occupying lesion in the head of the pancreas and tumors in the liver. F-18 fluorodeoxyglucose positron emission tomography revealed accumulation of isotope corresponding to a tumor of the pancreas with a standardized uptake value of 4.3, and tumors in the liver with standardized uptake values of 2.4 and 2.8. The serum glucagon level was high (1,170 pg/ml) and the secretin tolerance test was negative. She was diagnosed with glucagonoma with a high serum glucagon level and clinical findings. It is suggested that glucagonoma may be one of the tumors which show high uptake of F-18 fluorodeoxyglucose.

Physiological FDG uptake in the palatine tonsils

In clinical F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies of the head and neck region, remarkable symmetric tonsillar FDG uptake is sometimes observed. We determined the incidence and degree of tonsillar FDG uptake and investigated the significance of tonsillar FDG uptake. Between June 1998 and August 1998, we obtained informed consent from 17 patients who were scheduled to undergo a FDG-PET study for their own disease (11 men and 6 women; aged 22 to 77 yr) and who did not have head and neck disease to perform FDG-PET scanning of the head and neck region in addition to their target organs. The incidence and degree of tonsillar FDG uptake were determined. Remarkable tonsillar FDG uptake was found in 9 patients. The SUVs of these FDG uptakes ranged from 2.48 to 6.75, with a mean of 4.29 +/- 1.20 (SD). Tonsillar FDG uptakes in the remaining 8 patients were not remarkable, and their SUVs ranged from 1.93 to 3.31, with a mean of 2.46 +/- 0.45. Head and neck disease does not appear to have been responsible for the increase in tonsillar FDG uptake. Differences among tonsillar FDG uptake in these 17 patients without head and neck disease appear to reflect differences in activity of "physiological" inflammation of the palatine tonsils.

Positron emission tomography using 2-[(18)F] fluoro-2-deoxy-D-glucose in the diagnosis of uterine leiomyosarcoma: a case report

The preoperative diagnosis of uterine leiomyosarcoma (LMS) is very difficult. Magnetic resonance (MR) imaging is usually used for it; however, precise diagnosis by MR imaging is limited to typical LMS with coagulative tumor cell necrosis. We presented a case of LMS that was diagnosed preoperatively by positron emission tomography (PET) using 2-[(18)F] fluoro-2-deoxy-D-glucose (FDG).

Positron emission tomography with (18)F-fluorodeoxyglucose of uterine sarcoma: a comparison with magnetic resonance imaging and power Doppler imaging

OBJECTIVE

The effectiveness of positron emission tomography with (18)F-fluorodeoxyglucose (FDG-PET) for diagnosis of uterine sarcoma was evaluated in comparison to the effectiveness of magnetic resonance (MR) imaging and power Doppler imaging.

METHOD

The cases of five Osaka City University Hospital patients diagnosed with uterine sarcoma based on histopathological examination, in whom FDG-PET, MR imaging, and power Doppler imaging studies had been performed preoperatively, were reviewed. A comparative study of the usefulness of these three imaging modalities for diagnosis of sarcoma was conducted. Tumors comprised three leiomyosarcomas, one endometrial stromal sarcoma, and one carcinosarcoma.

RESULTS

FDG-PET examinations were 100% positive for the five sarcomas; MR imagings were 80% positive (four of five cases), and US was 40% positive (two of five cases). The mean standardized uptake value of the sarcomas was 4.5 +/- 1.3.

CONCLUSION

The sarcoma lesions were clearly imaged by FDG-PET. FDG-PET may be a most useful diagnostic method for uterine sarcoma.

Positron emission tomographic imaging of acoustic neuromas

Positron emission tomography (PET) examination with both [11C]methyl-l-methionine (Met) and [18F]fluoro-2-deoxyglucose (FDG) was performed in the same patients with acoustic neuroma wherever possible in order to compare the usefulness of the two methods. The study included six patients who visited the Osaka City University Hospitals, between April 1994 and October 1998, for complaints associated with acoustic neuroma. All patients were examined by magnetic resonance imaging (MRI) and Met-PET. Four patients were examined by FDG-PET. The tumor's region of highest accumulation was selected as the region of interest; the tumor/normal ratio (T/N ratio) was defined as the ratio of radioisotope counts for tumor and normal gray matter. All tumors in this series were detected by MRI. In the Met-PET images, four tumors were easily identified, with a high T/N ratio. However, two tumors could not be identified using Met-PET. On FDG-PET, no cases could be identified. The T/N ratio for the four patients with positive Met-PET findings averaged 1.694 +/- 0.266. PET, especially Met-PET, is a powerful means of examination providing functional information on tumors in acoustic neuroma. Met-PET may therefore be useful for acoustic neuroma, which is known to proliferate slowly, as for malignant tumors, in evaluating the proliferating potential of a tumor, in determining patients in whom to perform radiological treatment and in monitoring post-treatment progress.

Diagnosis of metastasis of ovarian clear cell carcinoma to the peritoneum of the abdominal wall by positron emission tomography with (fluorine-18)-2-deoxyglucose

A 43-year old woman, operated on for ovarian clear cell carcinoma (stage IIc) four years previously was found to have a small mass under the abdominal wall in the right lower quadrant of the abdomen. Neither diagnostic imaging (ultrasonography and MRI) nor tumor markers showed any evidence of recurrence, but positron emission tomography revealed a hot spot area, and it was diagnosed as recurrence of the ovarian carcinoma. The postoperative histopathological diagnosis was metastasis of ovarian carcinoma to the peritoneal wall.

The role of 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) in the diagnosis of recurrence and lymph node metastasis of cervical cancer

The usefulness of positron emission tomography with 2-[18F]-fluoro-2-deoxy-D-glucose (FDG-PET) in diagnosing recurrence and lymph node metastasis of uterine cervical cancer was evaluated as a preliminary study. The FDG uptake of 13 cervical cancer patients, including 4 patients with recurrence, was evaluated. The FDG uptake of the cervices of 5 patients who underwent PET studies for non-cervical tumors were used as control. In 2 patients who had undergone radical hysterectomy, we compared the diagnosis of lymph node metastasis based on FDG-PET and magnetic resonance imaging. The FDG uptake in the 9 primary cervical cancers was greater than that in normal cervices (p=0.025). Examination of the 4 recurrent tumors revealed a higher FDG uptake than that in normal cervices (p=0.0022). Metastatic lesions in lymph nodes showed an accumulation of FDG on the PET scan. In conclusion, FDG-PET may be an effective diagnostic tool for detecting recurrence and lymph node metastasis of uterine cervical cancers.

Glucose modifies the cross-talk between insulin and the beta-adrenergic signalling system in vascular smooth muscle cells

BACKGROUND

Abnormalities in the vascular function of insulin are observed in insulin resistance, and hyperglycaemia is one of the important factors inducing insulin resistance.

OBJECTIVE

To investigate the role of glucose in the interaction of insulin and beta-adrenergic signalling systems in vascular smooth muscle cells (VSMC).

METHODS

After cells were treated with D-glucose (525 mmol/l) and insulin (100 nmol/l), adenylyl cyclase activity was measured in the presence of isoproterenol, forskolin, and cholera toxin. Assays for insulin-induced activities of insulin receptor substrate (IRS)-1, phosphoinositide 3-kinase (PI3-K) and mitogen-activated protein kinase (MAPK) were performed.

RESULTS

In the presence of low glucose concentrations (5 mmol/l), insulin enhanced isoproterenol-, forskolin- and cholera toxin-stimulated adenylyl cyclase activities. This stimulatory effect was abolished by PI3-K inhibitors, wortmannin, or LY294002. In contrast, in the presence of high glucose concentrations (25 mmol/l), insulin attenuated isoproterenol-stimulated activity but not cholera toxin- or forskolin-stimulated activity. Insulin-stimulated activities of IRS-1 and PI3-K, but not MAPK activity, were also attenuated in the presence of high concentrations of glucose. The MAPK kinase inhibitor, PD98059, abolished the inhibitory effect of insulin on the beta-adrenergic signalling system. Troglitazone and pioglitazone prevented this inhibitory effect of insulin by restoring IRS-1 and PI3-K activities.

CONCLUSIONS

In the presence of low glucose concentrations, insulin stimulates the beta-adrenergic signalling system through the IRS-1/PI3-K pathway. However, in the presence of high glucose concentrations, the effect of insulin is switched to an inhibitory one, through the MAPK pathway. Our finding suggests that high glucose concentrations modify the cross-talk between insulin and the beta-adrenergic signalling systems in VSMC.

High glucose attenuates insulin-induced mitogen-activated protein kinase phosphatase-1 (MKP-1) expression in vascular smooth muscle cells

The mechanisms for the effect of hyperglycemia on insulin-induced mitogenesis were investigated using rat vascular smooth muscle cells (VSMC). VSMC were preincubated in serum-free medium with low (5 mM) glucose (LG condition) or high (25 mM) glucose (HG condition), and examined for DNA synthesis using bromodeoxyuridine (BrdUrd) incorporation. Mitogen-activated protein kinase (MAPK) activity and MAPK phosphatase (MKP-1) protein expression were detected by Western blot analysis. Phosphatidylinositol 3-kinase (PI-3K) activity was detected by thin layer chromatography. Insulin induced a dose-dependent increase in BrdUrd incorporation (123.3+/-2.6% over basal level with 1 microM insulin) in the LG group and this effect was significantly enhanced (161.6+/-10.4% over basal level) in the HG group. In the LG group, MAPK activity was transient with a peak activation (137.4+/-11.2% over basal level) after 10 min exposure to 100 nM insulin. In the HG group, the MAPK activity was significantly potentiated (two-fold compared to the LG group) and was sustained even after 60 min. Insulin also induced PI-3K activity and MKP-1 expression, both of which were blocked by the PI-3K inhibitor wortmannin. In the HG group, insulin-induced PI-3K and MKP-1 expression was almost abolished. In conclusion, high glucose enhances insulin-induced mitogenesis associated with the potentiation of insulin-stimulated MAPK activity in VSMC. These effects of glucose might in part be due to the attenuation of MKP-1 expression through the blockage of the insulin-PI-3K signal pathway.

Clinical usefulness of positron emission tomography with fluorine-18-fluorodeoxyglucose in the diagnosis of liver tumors

We studied various liver tumors by positron emission tomography with fluorine-18 fluorodeoxyglucose (FDG-PET) to examine the diagnostic usefulness of this technique. We also examined the relation between findings on FDG-PET and the characteristics of hepatocellular carcinoma. FDG-PET was performed in 78 patients with liver tumors, including 53 with primary liver cancer [48 hepatocellular carcinomas (HCC) and 5 cholangiocellular carcinomas (CCC)], 20 with metastatic liver cancer, 2 with liver hemangioma, and 3 with focal nodular hyperplasia. For quantitative evaluation, a region of interest (ROI) was placed over the entire tumor region, at the level of the maximum diameter of the tumor. A background ROI was then placed over the non-tumor region of the liver. The average activity within each ROI was subsequently corrected for radioactive decay, and the standardized uptake value (SUV) was calculated by dividing the tissue activity by the injected dose of radioactivity per unit body weight. SUV ratio was expressed as the tumor-to-non-tumor ratio of the SUV. The median SUV was significantly lower in HCC than in metastatic live cancer or CCC, and the median SUV ratio was significantly lower in HCC than in metastatic liver cancer or CCC. The median SUV was not higher in multiple HCC than in single HCC, but the median SUV ratio was significantly higher in multiple HCC than in single HCC. The median SUV and the median SUV ratio were significantly higher in the presence of portal vein thrombosis than in the absence of such thrombosis. The Cancer of the Liver Italian Program score and the alpha-fetoprotein value correlated significantly with both the SUV and SUV ratio. These results suggest that FDG-PET is clinically useful not only for the differential diagnosis of liver tumors but also for evaluation of the clinical characteristics of HCC.

Early diagnosis and evaluation of therapy in postoperative recurrent cervical cancers by positron emission tomography

Positron emission tomography (PET) using 2-[18F]fluoro-2 deoxy-D-glucose (FDG) was performed on two uterine cervical cancer patients in whom recurrent tumors, one pelvic and the other at the vaginal wall had not been precisely diagnosed using the usual imaging examinations. One recurrence was confirmed by the acccumulation of FDG to the pelvic mass as detected by magnetic resonance imaging (MRI). During chemotherapy, changes in FDG-PET findings were detected earlier than those in MRI. In the other, PET detected a recurrent tumor that could not be found by MRI, and was also useful for evaluating chemotherapeutic effects. These cases suggest that PET with FDG can be a useful examination not only for diagnosing recurrent cervical cancer after radical hysterectomy, especially pelvic recurrence, but also for evaluating chemotherapeutic effects on recurrent cancers.

Clinical usefulness of scintigraphy with 99mTc-galactosyl-human serum albumin for prognosis of cirrhosis of the liver

Scintigraphy with 99mTc-diethylenetriamine pentaacetic acid-galactosyl-human serum albumin (99mTc-GSA) is useful for evaluating hepatic functional reserve. We assessed the clinical usefulness of this technique, including its value in establishing a prognosis, in patients with cirrhosis of the liver.

METHODS

Scintigraphy with 99mTc-GSA was performed in 10 healthy subjects, 42 patients with chronic hepatitis and 158 patients with cirrhosis. Computer acquisition of gamma camera data were started just before the injection of 99mTc-GSA. Time-activity curves for the heart and liver were generated from regions of interest (ROIs) for the heart and the entire liver. A receptor index was calculated by dividing the radioactivity of the liver ROI by that of the liver-plus-heart ROI 15 min after the injection. An index of blood clearance was calculated by dividing the radioactivity of the heart ROI at 15 min by that of the heart ROI at 3 min.

RESULTS

The median receptor index was lower in patients with cirrhosis than in patients with chronic hepatitis or in healthy subjects, and the median index of blood clearance was higher. The receptor index was significantly lower when a complication (varices, ascites) was present. The index of blood clearance was significantly higher when a complication (varices and ascites) was present. Correlation of the two indices with classic indicators for functional reserve was significant. On the basis of the receptor index, the patients with cirrhosis were divided into two groups of roughly equal size: group A, receptor index over 0.85, and group B, receptor index 0.85 or less. On the basis of the index of blood clearance, the patients with cirrhosis were divided into two groups of roughly equal size: group A, index of blood clearance < 0.70, and group B, index of blood clearance > or = 0.70. The cumulative survival rates were lower in group B than in group A.

CONCLUSION

Scintigraphy with 99mTc-GSA is clinically useful, especially in establishing the prognosis of patients with cirrhosis of the liver.

Thallium and FDG uptake by atelectasis with bronchogenic carcinoma

We report a case of bronchogenic carcinoma with atelectasis studied by T1-SPECT and FDG-PET. In the carcinoma, abnormally high uptake of T1 and FDG were detected, but in the region of atelectasis, an abnormally high uptake of T1 with a relatively low uptake of FDG were observed. On quantitative analyses, the T1 retention indexes of the tumor and atelectasis were 29.7 and 42.0. The mean SUVs of FDG of the tumor and the atelectasis were 8.92 and 1.28. T1-SPECT could not distinguish the atelectasis from the carcinoma. FDG-PET was superior to T1-SPECT in this case in detecting malignancy and distinguishing it from atelectasis.

Two cases of chronic tonsillitis studied by FDG-PET

We report two cases of chronic tonsillitis studied by FDG-PET. Symmetrical high FDG uptake by the tonsils was observed in both cases. On histopathologic examination of the resected tonsils, follicular hyperplasia was observed with proliferation of lymphocytes in the germinal centers. Increased glucose metabolism in active inflammation involving lymphocyte proliferation was thought to be a cause of high FDG uptake by tonsils in chronic tonsillitis.

Lovastatin prevents angiotensin II-induced cardiac hypertrophy in cultured neonatal rat heart cells

Angiotensin II activates p21ras, and mediates cardiac hypertrophic growth through the type 1 angiotensin II receptor in cardiac myocytes. An inhibitor of 3-hydroxy-3-methyglutaryl-coenzyme A (HMG-CoA) reductase has been shown to block the post-translational farnesylation of p21ras and inhibit protein synthesis in several cell types. Primary cultures of neonatal cardiac myocytes were used to determine whether HMG-CoA reductase inhibitors, lovastatin, simvastatin and pravastatin inhibit the angiotensin II-induced hypertrophic growth. Angiotensin II (10(-6) M) significantly increased protein-DNA ratio, RNA-DNA ratio, ratios of protein synthesis and mitogen-activated protein (MAP) kinase activity. Lipid-soluble HMG-CoA reductase inhibitors, lovastatin (10(-6) M) and simvastatin (10(-6) M) partially and significantly inhibited the angiotensin II-induced increases in these parameters, but a water-soluble HMG-CoA reductase inhibitor, pravastatin (10(-6) M) did not. Mevalonate (10(-4) M) overcame the inhibitory effects of lovastatin and simvastatin on angiotensin II-induced increases in these parameters. A selective protein kinase C inhibitor, calphostin C (10(-6) M) partially and significantly prevented angiotensin II-induced increases in these parameters, and treatment with both lovastatin and calphostin C inhibited completely. Angiotensin II increased p21ras activity and membrane association, and lovastatin inhibited them. These studies demonstrate that a lipid-soluble HMG-CoA reductase inhibitor, lovastatin, may prevent angiotensin II-induced cardiac hypertrophy, at least in part, through p21ras/MAP kinase pathway, which is linked to mevalonate metabolism.

Use of scintigraphy with 99mtechnetium galactosyl human serum albumin for staging of primary biliary cirrhosis and assessment of prognosis

BACKGROUND

Conventional models for prediction of survival in patients with primary biliary cirrhosis (PBC) are based on the results of blood tests and on the clinical condition, which may be affected by treatment. We evaluated the usefulness of hepatic receptor imaging with [99mtechnetium]-diethylenetriaminepentaacetic acid galactosyl human serum albumin (GSA) for the staging and prognosis of PBC without the need for reference to laboratory test results.

METHODS

The subjects were 45 patients with PBC, 10 healthy subjects, 62 patients with chronic hepatitis and 144 patients with cirrhosis. Computer acquisition of gamma-camera data was started just before the injection of 185 MBq [99mTc]-GSA and was stopped 20 min later. Time-activity curves were generated from regions of interest (ROI) for the heart and liver. A receptor index was calculated by dividing the radioactivity of the liver ROI by that of the liver-plus-heart ROI 15 min after the injection. An index of blood clearance was calculated by dividing the radioactivity of the heart ROI 15 min after the injection by that of the heart ROI 3 min after the injection.

RESULTS

The median receptor index was higher in patients with PBC than in those with cirrhosis. Among patients with PBC, the receptor index was lower in those with stage IV disease than in those in stages I, II or III. The index of blood clearance was lower in patients with PBC than in those with cirrhosis. Among patients with PBC, the index of blood clearance was higher in those with stage IV disease than in those in stages I, II or III. The receptor index was correlated significantly both to the risk score of the Mayo model and to the prognostic index of the Japanese model. The index of blood clearance was also correlated significantly to this score and prognostic index.

CONCLUSIONS

Hepatic receptor imaging with [99mTc]-GSA is useful for the evaluation of hepatic functional reserve, staging of PBC and assessment of prognosis.

Positron emission tomographic imaging of pleomorphic adenoma in the parotid gland

We studied the possible correlation between 2-18F-2-deoxy-D-glucose (FDG) uptake and histopathological findings in mass lesions of the parotid gland. Thirteen pleomorphic adenomas of the parotid gland were evaluated by computed tomography (CT), magnetic resonance imaging (MRI), Gallium scintigraphy, Technetium scintigraphy and FDG-positron emission tomography (PET). Standardized uptake values (SUV) and time-activity curves (TAC) were determined for all mass lesions. Pleomorphic adenomas were histologically classified into the following three types: epithelial, intermediate and mesenchymal, based on their dominant histological components. The numbers of epithelial, intermediate, and mesenchymal types were 5, 2, and 6, respectively. The levels of SUVs were 4.02 +/- 1.91 (range: 1.97-7.07) in the epithelial type, 5.05 +/- 1.12 (range: 4.26-5.58) in the intermediate type and 3.98 +/- 7.74 (range: 1.98-7.74) in the mesenchymal type, respectively. The accumulation of FDG did not differ significantly among the three types. Since the accumulation of FDG was significantly correlated with the tumor size, FDG-PET could reflect tumor growth ability more apparently than the other nuclear or imaging modalities.

Fluorine-18 fluorodeoxyglucose positron emission tomography imaging of parotid mass lesions

Using X-ray CT or magnetic resonance imaging (MRI), fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET) studies were performed in 28 patients with parotid lesions. All lesions except two showed higher accumulation of FDG than normal parotid gland. High accumulation was found in all of 5 carcinomas, all of 6 Warthin's tumors, and 8 of 12 pleomorphic adenomas, with standardized uptake values (SUVs) over 3.0. The mean SUVs of carcinomas, Warthin's tumors, and pleomorphic adenomas were 5.92 +/- 2.05, 7.03 +/- 2.49, and 4.07 +/- 1.55, respectively. On the other hand, all 5 inflammatory lesions demonstrated low accumulation, with mean SUVs of 1.66 +/- 0.89. It is thus difficult to differentiate malignant from benign parotid lesions by SUV on FDG-PET.

Monitoring of response to radiotherapy with fluorine-18 deoxyglucose PET of head and neck squamous cell carcinomas

We examined the usefulness of positron emission tomography (PET) using fluorine-18 deoxyglucose (FDG) in determining the therapeutic effects of irradiation and chemotherapy on head and neck malignant tumors. Twenty-two patients with head and neck lesions who underwent histological examinations were studied. Squamous cell carcinoma was histologically diagnosed in all cases. Sixteen of them underwent radiotherapy with approximately 40 Gy in combination with carboplatin therapy. The remaining 6 patients underwent radiotherapy alone. After these treatments, 11 underwent surgery. For PET study, each patient was injected with intravenous FDG 185-370 MBq. We evaluated the degree of FDG accumulation using scanned images taken 40-55 min after the injection. We measured the standardized uptake value (SUV), a semiquantative evaluation, ROI activity divided by the dosage per weight of each patient. FDG-PET, CT and MRI were performed twice for each patient, before and after treatment. FDG uptake, but not the tumor size in CT or MRI, was significantly reduced in each patient after the treatment. Therefore, our findings have clearly demonstrated that FDG-PET provides for more valuable therapeutic outcomes than conventional imaging such as CT and MRI. FDG-PET should thus provide a new dimension in the management of head and neck malignant tumors.

Usefulness of per-rectal portal scintigraphy with Tc-99m pertechnetate for galactosemia in infants

Galactosemia discovered by newborn screening is rarely caused by enzyme deficiency. It has recently been reported that among patients without enzyme deficiency portosystemic shunting may be a cause of galactosemia in some patients. We did per-rectal portal scintigraphy in patients with such galactosemia detected during screening of newborns to examine the usefulness of this method for the diagnosis of portosystemic shunts via the inferior mesenteric vein. The subjects were eight neonates with galactosemia without enzyme deficiency detected during screening. A solution containing technetium-99m pertechnetate was instilled into the rectum, and serial scintigrams were taken while radioactivity curves for the liver and heart were recorded sequentially. The per-rectal portal shunt index was determined by calculating the ratio for counts of the liver to counts for the heart integrated for 24 seconds immediately after the appearance of the liver time-activity curve. A portosystemic shunt was detected in both of the patients with a shunt index of 30% or more, but not in the six patients with a shunt index less than 30%. The blood galactose levels of these six patients later entered the reference range. This method is noninvasive and there is little exposure to the radionuclide. It seemed to be useful for the diagnosis of portosystemic shunt in newborns with galactosemia without enzyme deficiency.

A case of oophoritis detected by gallium-67-citrate scintigraphy

A 39-year-old woman with fever of unknown origin was admitted to our hospital. Whole body scintigrams with 67Ga-citrate showed an abnormal accumulation of radioactivity in the pelvic cavity. Cystadenocarcinoma of the ovary was suspected on the basis of findings obtained by abdominal computed tomography and magnetic resonance imaging. Left oophorectomy was performed, and oophoritis was diagnosed. We would like to propose that 67Ga-citrate scintigraphy may be useful for the diagnosis of oophoritis as well as gynecologic malignant tumors.

A case of cap polyposis investigated by scintigraphy with human serum albumin labeled with Tc-99m DTPA

Cap polyposis is a rare intestinal disease that can be difficult to differentiate from inflammatory bowel disease. When cap polyposis is suspected, it is important to confirm protein loss. A 54-year-old woman who had been treated for ulcerative colitis for 7 years had severe hypoproteinemia. Scintigraphy with Tc-99m-labeled DTPA complexed with human serum albumin showed protein loss from the descending colon. Left hemicolectomy and sigmoid colectomy were performed. Cap polyposis was diagnosed on the basis of histologic findings from an operative specimen. The patient's diarrhea resolved after surgery and her hypoproteinemia improved. Scintigraphy with this label gave information helpful in the diagnosis of cap polyposis.

Relatively high F-18 fluorodeoxyglucose uptake in paranasal sinus aspergillosis: a PET study

We report a case of maxillary sinus (MS) aspergillosis studied by positron emission tomography (PET) with F-18 fluorodeoxyglucose (FDG) and by 67Ga-citrate (Ga) single photon emission computed tomography (SPECT). The FDG uptake existed in the lesion and along the inflammatory edematous mucous membrane of the MS. Ga uptake occurred not only in the lesion and in the mucous membrane but also in the MS. Relative quantification, the standardized uptake value (SUV) of the lesion showed relatively high FDG uptake (3.7). But in other reports, many malignant head and neck tumors had a SUV below 3.7. It was thought to be difficult to differentiate between aspergillosis and malignant head and neck tumors by FDG-PET.

Usefulness of scintigraphy with Tc-99m phytate for the diagnosis of alcoholic foamy degeneration

PURPOSE

Alcoholic foamy degeneration (AFD) is a liver disease causing temporary hepatocyte dysfunction. The prognosis is usually good, but liver biopsy is needed for diagnosis. We report the usefulness of liver-spleen scintigraphy with the radiocolloid Tc-99m phytate for the diagnosis of AFD.

PATIENTS AND METHODS

We used liver scintigraphy with Tc-99m phytate to study three patients with AFD diagnosed on the basis of findings from a liver biopsy.

RESULTS

Liver-spleen scintigraphy showed hepatomegaly and splenomegaly, and bone marrow was visible, but radioisotope uptake by the liver was uniform.

CONCLUSIONS

This pattern of scintigraphic findings is different from that reported for patients with alcoholic fatty livers or severe alcoholic hepatitis, and seems to be specific for AFD.

Enhanced expression of heparin-binding EGF-like growth factor and its receptor in hypertrophied left ventricle of spontaneously hypertensive rats

OBJECTIVES

Although heparin-binding epidermal growth factor-like growth factor (HB-EGF) is thought to produce hypertrophy in isolated cardiomyocytes via an autocrine mechanism, the pathophysiological role of HB-EGF, in myocardial hypertrophy in vivo, is not yet known. To investigate the involvement of HB-EGF in cardiac remodeling associated with hypertension in vivo, we assayed the expression of HB-EGF mRNA and protein in the left ventricle (LV) during the development of left ventricular hypertrophy in spontaneously hypertensive rats (SHR).

METHODS

Prior to sacrifice and assay of HB-EGF and EGF-receptor (EGF-R) mRNA, morphologic and hemodynamic variables were measured in SHR and in age-matched Wistar Kyoto rats (WKY). At 5, 9 and 12 weeks of age, rats were killed, their hearts were removed, and the expression of HB-EGF and EGF-R mRNA and protein were measured. In addition, SHR and WKY were treated with enalapril, atenolol, or both for 4 weeks.

RESULTS

In untreated SHR, double products (i.e. systolic blood pressure (sBP) multiplied by heart rate (HR), an index of mechanical load, peaked at 9 weeks. Expression of HB-EGF mRNA was also observed to peak in these animals at 9 weeks, while expression of EGF-R mRNA increased from 5 to 9 weeks, but remained constant thereafter. In untreated WKY, double products and EGF-R mRNA expression did not change over time, whereas the level of HB-EGF message increased gradually. Antibody to HB-EGF reacted primarily with myocyte membranes in SHR, whereas antibody to EGF-R reacted mainly with interstitial cells in these animals. The angiotensin-converting enzyme inhibitor, enalapril, markedly decreased sBP in SHR, whereas the beta 1-adrenoreceptor antagonist, atenolol, significantly decreased HR. While neither alone affected the expression of HB-EGF mRNA, their combination significantly reduced the expression of HB-EGF mRNA, as well as double products, in these rats, but had no effect on expression of EGF-R mRNA.

CONCLUSIONS

The enhanced expression of HB-EGF mRNA and protein in LV of SHR suggest that this growth factor may play an important role during the early development of LV hypertrophy and cardiac fibrosis in SHR. The association between double products and HB-EGF expression suggest that the latter may be induced by increased mechanical load and may contribute, in turn, to cardiac remodeling.

[A comparative study of imaging of myocardial perfusion with 201Tl-SPECT and 13NH3-PET: visual and quantitative evaluation]

We compared the results of visual and quantitative evaluation of imaging of myocardial perfusion with 201Tl-SPECT and 13NH3-PET in the 7 non-myocardial infarction (non-MI) and 42 myocardial infarction (MI) patients. On the 201Tl-SPECT and 13NH3-PET imaging, the degree of accumulation of each radioisotope (RI) was visually classified into four grades of defect score. The percentage of uptake was also quantitatively evaluated.

RESULTS

In the 7 non-MI patients, NH3% uptake in the lateral wall was significantly lower than in the septum, and in the lateral wall NH3% uptake was significantly lower than Tl% uptake. For the 42 MI patients, segmental defect scores (DS) on 201Tl-SPECT were compared with those on 13NH3-PET, and a high degree of concordance in DS was found for all territories of the left ventricle, antero-septum MI and inferior MI territories. Average Tl% uptake/NH3% uptake was near 1, a highly positive correlation was found between Tl% uptake and NH3% uptake in all territories of the left ventricle and antero-septum MI territories, and Tl% uptake/NH3% uptake was larger than 1, but, a significant positive correlation existed between Tl% uptake and NH3% uptake in the territory with inferior MI.

CONCLUSION

These findings indicate that results of 201Tl-SPECT imaging were similar to those of 13NH3-PET in evaluation of myocardial perfusion in the antero-septum and inferior. However, a difference in distribution was observed between 201TlCl and 13NH3 in the lateral wall, indicating that particular attention should be paid to the results of imaging of myocardial perfusion in the lateral wall.

A method to reduce the frequency fluctuation in a phase-shift transistor oscillator

The frequency and current fluctuations, and their correlation were measured in a phase shift transistor oscillator. The spectra are of 1/f type and both are correlated. A demonstration was carried out to reduce the frequency fluctuation, and a useful method to reduce the fluctuation is proposed in an oscillator.

Caveolin interaction with protein kinase C. Isoenzyme-dependent regulation of kinase activity by the caveolin scaffolding domain peptide

Caveolar localization of protein kinase C and the regulation of caveolar function by protein kinase C are well known. This study was undertaken to examine whether caveolin subtypes interact with various protein kinase C isoenzymes using the caveolin scaffolding domain peptide. When protein kinase C-alpha, -epsilon, and -zeta were overexpressed in COS cells followed by subcellular fractionation using the sucrose gradient method, all the isoenzymes (alpha, epsilon, and zeta) were detected in the same fraction as caveolin. The scaffolding domain peptide of caveolin-1 and -3, but not -2, inhibited the kinase activity and autophosphorylation of protein kinase C-alpha and -zeta, but not of protein kinase C-epsilon, overexpressed in insect cells. Truncation mutation studies of the caveolin-1 and -3 peptides demonstrated that a minimum of 16 or 14 amino acid residues of the peptide were required for the inhibition or direct binding of protein kinase C. Thus, the caveolin peptide physically interacted with protein kinase C and regulated its function. Further, this regulation occurred in a protein kinase C isoenzyme-dependent manner. Our results may provide a new mechanism regarding the regulation of protein kinase C isoenzyme activity and the molecular interaction of protein kinase C with its putative binding proteins.

Regulation of adenylyl cyclase isoforms by N-alkanols

We examined the effect of n-alkanols on adenylyl cyclase isoforms (types II and V) overexpressed in insect cells. Ethanol stimulated the type II isoform but not the type V isoform. Ethanol stimulated type II adenylyl cyclase greater than GTP gamma S, and the treatment of the membrane with GDP beta S or cholera toxin did not affect this stimulation. Other n-alkanols inhibited type V adenylyl cyclase activity in proportion to their lipophilic potency. In contrast, type II adenylyl cyclase was stimulated by weakly lipophilic n-alkanols and inhibited by strongly lipophilic n-alkanols. When solubilized membranes and purified preparations were used, all the n-alkanols inhibited type II adenylyl cyclase. Our data suggest that n-alkanols regulated adenylyl cyclase isoform-dependently. Stimulation of the type II isoform was independent from the interaction with Gs alpha but required the presence of an intact membrane structure. Our study may provide another step to understanding how membrane protein subtypes are differentially regulated by n-alkanols.

[A case of an adult neuroblastoma with bone-marrow metastases: 131I-MIBG scintigraphy in comparison with MRI]

To detect a primary neuroblastoma lesion and its metastases, 131I-MIBG scintigraphy was performed for a 24-year-old woman who had a high level of serum catecholamine. 131I-MIBG scintigrams showed high radioactivity in the left upper quadrant, pelvic bone, and vertebral bodies. A biopsy of the pelvic bone revealed metastasis from the neuroblastoma. After four chemotherapy courses, the accumulation of 131I-MIBG decreased after each course; however, scintigraphy performed after the last chemotherapy course showed focal mild uptake in the right sacroiliac. The presence of residual tumor in the sacroiliac was confirmed histologically. On the other hand, T1-weighted and T2-weighted MR images performed before the treatment showed low signal intensity and high signal intensity in the pelvic bone, respectively. After the fourth chemotherapy course, T2-weighted MR images showed low signal intensity in the pelvic bone; however, it was difficult to determinate whether it should improve. To assess the effect of treatment of neuroblastoma, 131I-MIBG scintigraphy was considered more useful than MRI.

[Secretion of atrial natriuretic peptide from the left ventricle and heart in patients with hypertrophic cardiomyopathy: relationship with hemodynamic and echocardiographic profiles]

This study investigated whether atrial natriuretic peptide (ANP) secretion from the left ventricle occurs and correlated any secretion with the hemodynamic or echocardiographic parameters in patients with hypertrophic non-obstructive cardiomyopathy (HNCM). Volume overload was induced by intravenous injection of low-molecular weight dextran in 19 patients with HNCM and seven normal subjects (control group). Simultaneous measurements of plasma ANP concentrations in the aortic root, anterior interventricular vein and coronary sinus, and hemodynamic parameters were performed before and after volume overload. Echocardiographic parameters were measured under the basal conditions in the HNCM group. There was no difference in ANP concentrations between the aorta and anterior interventricular vein either before or after volume overload in the control group, whereas they were significantly higher in the anterior interventricular vein than in the aorta both before and after volume overload in the HNCM group, suggesting increased ANP secretion from the left ventricle. Moreover, the difference in ANP concentrations between these locations was enhanced by volume overload. In the HNCM group, the differences in ANP concentrations between these locations were positively correlated with the pulmonary capillary wedge pressure and left ventricular end-diastolic pressure before and after volume overload, but not with left ventricular thickness or left atrial dimension. These results suggest that enhanced ANP secretion from the left ventricle in both basal and volume overloaded states occurs in HNCM, and this ANP secretion from the left ventricle is closely related to left ventricular end-diastolic pressure but not to wall thickness and mass index of left ventricle.

Isoform-specific regulation of adenylyl cyclase by oxidized catecholamines

Both epinephrine and manganese are known to stimulate cAMP production in cardiac homogenates. When added together, however, they inhibited adenylyl cyclase catalytic activity. Type V adenylyl cyclase, the major isoform in the heart, was also inhibited when an increasing concentration of epinephrine was added in the presence of manganese. Inhibition was not dependent on the condition of stimulation or preparation of the enzyme. However, this inhibition was abolished in the presence of anti-oxidant. Other catecholamines, including dopamine and isoproterenol, as well as adrenochrome, an oxidized product of epinephrine, similarly inhibited the activity of this enzyme. Kinetic analyses revealed that the K(m) for the substrate ATP was unchanged, but the V(max) was significantly decreased. In contrast, type II adenylyl cyclase, a non-cardiac isoform, was resistant to such inhibition by adrenochrome and was somewhat stimulated by it. Thus, catecholamines, when oxidized, directly interacted with adenylyl cyclase in an isoform-specific manner in the absence of G proteins. Our findings suggest that adenylyl cyclase isoforms have different sensitivity to various stresses, including oxidative stress.

18F-fluorodeoxyglucose positron emission tomography and the prognosis of patients with pancreatic adenocarcinoma

BACKGROUND

Fluorodeoxyglucose (FDG) detected by positron emission tomography (PET) can be used to measure the glycolytic activity of tumor cells. Though the prognosis of patients with pancreatic adenocarcinoma is usually poor, a subset of patients with good prognoses may be discovered by determining the degree of FDG integration into tumors.

METHODS

Fourteen patients with histologically proven pancreatic adenocarcinoma underwent 18F-FDG PET. The standardized uptake value (SUV) of 18F-FDG was calculated, and the patients were divided into high (> or = 3.0) and low (< 3.0) SUV groups.

RESULTS

The two groups were not significantly different in terms of age, tumor location and size, staging, and treatment. However, analysis by the Kaplan-Meier method revealed that the groups had different prognoses (log rank test, P < 0.05). The mean survival of patients with high SUV was 5 months, whereas that of patients with low SUV was 14 months. There were not strong correlations between the SUVs and tumor size (0.56), serum carbohydrate antigen 19-9 (0.39), or carcinoembryonic antigen (0.52).

CONCLUSIONS

SUV calculated with 18F-FDG can be utilized as a prognostic factor for patients with pancreatic adenocarcinoma.