Masanobu Hagiike

18F-fluorodeoxyglucose positron emission tomography in the diagnosis of small pancreatic cancer

AIMnTo investigate the role of (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) in the diagnosis of small pancreatic cancer.nnnMETHODSnThis study involved 31 patients with proven invasive ductal cancer of the pancreas. The patients were divided into 3 groups according to the maximum diameter of the tumor: TS1 (maximum tumor size ≤ 2.0 cm), TS2 (> 2.0 cm and ≤ 4.0 cm) or TS3-4 (> 4.0 cm). The relationships between the TS and various diagnostic tools, including FDG-PET with dual time point evaluation, were analyzed.nnnRESULTSnThe tumors ranged from 1.3 to 11.0 cm in diameter. Thirty of the 31 patients (97%) had a positive FDG-PET study. There were 5 patients classified as TS1, 15 as TS2 and 11 as TS3-4. The sensitivity of FDG-PET, computed tomography (CT) and magnetic resonance imaging (MRI) were 100%, 40%, 0% in TS1, 93%, 93%, 89% in TS2 and 100%, 100%, 100% in TS3-4. The sensitivity of FDG-PET was significantly higher in comparison to CT and MRI in patients with TS1 (P < 0.032). The mean standardized uptake values (SUVs) did not show a significant difference in relation to the TS (TS1: 5.8 ± 4.5, TS2: 5.7 ± 2.2, TS3-4: 8.2 ± 3.9), respectively. All the TS1 tumors (from 13 to 20 mm) showed higher SUVs in FDG-PET with dual time point evaluation in the delayed phase compared with the early phase, which suggested the lesions were malignant.nnnCONCLUSIONnThese results indicate that FDG-PET with dual time point evaluation is a useful modality for the detection of small pancreatic cancers with a diameter of less than 20 mm.

Detection of colorectal cancer using 18F-FLT PET: comparison with 18F-FDG PET

ObjectiveWe investigated the feasibility of 3′-deoxy-3′-18F-fluorothymidine (FLT) positron emission tomography (PET) for the detection of colorectal cancer, in comparison with 2-deoxy-2-18F-fluoro-D-glucose (FDG) PET, and investigated correlation of the two radiotracers used with proliferative activity as indicated by Ki-67 index. MethodsA total of 26 patients with newly diagnosed colorectal cancer were examined with FLT PET and FDG PET. Tumor lesions were identified as areas of focally increased uptake, exceeding that of surrounding normal tissue. For semiquantitative analysis, the maximal standardized uptake value (SUV) was calculated. ResultsIn all 26 patients, colorectal cancers were detected by both FLT PET and FDG PET. The mean (±SD) values of FLT SUV in colon cancer (5.4±2.4) and in rectal cancer (5.6±1.3) were significantly lower than the corresponding values of FDG SUV (12.4±6.3 and 12.5±4.7, respectively) (P<0.003). There was no significant correlation between Ki-67 index and either FLT SUV or FDG SUV. ConclusionAlthough uptake of FLT was found to be significantly lower than that of FDG, both FLT PET and FDG PET were able to detect colorectal cancers in all 26 patients. Neither of the two radiotracers used was correlated with proliferative activity.

Functional evidence for involvement of bumetanide-sensitive Na+K+2Cl− cotransport in the hepatoportal Na+ receptor of the Sprague–Dawley rat

To investigate mechanisms involved in hepatoportal Na+ sensing, responses of hepatic afferent nerve activity (HANA) to intraportal hypertonic NaCl injection were measured before, and after, intraportal infusion of inhibitors of Na+ transport systems. HANA increased in response to the intraportal injection of 0.75 M NaCl in a dose-dependent manner. The HANA response was not affected by amiloride or 4-acetamido-4-isothiocyanato-stilbene-2,2-disulfonic acid (SITS), but was suppressed in a dose-dependent manner by intraportal infusion of ouabain, furosemide, or bumetanide. These results indicate that the hepatoportal Na+ receptor senses the Na+ concentration via the bumetanide-sensitive Na+K+2Cl- cotransporter.

Role of the vestibular system in sudden shutdown of renal sympathetic nerve activity during microgravity in rats

The purpose of this study was to examine the effect of microgravity (muG) on renal sympathetic nerve activity (RNA) in rats. Additionally, we estimated the participation of the vestibular system in the response of RNA to muG. Eight normal Sprague-Dawley (SD) rats and five chemically and bilaterally labyrinthectomied SD rats were used to measure RNA during free-drop examination (4.5-s duration of muG); arterial pressure (AP) and aortic flow velocity (AFV) were additionally monitored. Although AFV showed no particular change, AP tended to decrease during muG in the later phase. Prior to this AP fall-off, RNA was immediately and markedly attenuated by muG. This attenuation was transient and RNA returned to 1G level within the mu;muG condition. Interestingly, this phenomenon remained even in labyrinthectomied rats. In conclusion, cephalad shift of the body fluid by loading of muG may cause cardiopulmonary low-pressure receptor activation and consequent RNA attenuation, but the participation of the vestibulosympathetic reflex in this phenomenon is not obvious.

Dihydropyrimidine dehydrogenase (DPD) activity in gastric cancer tissue and effect of DPD inhibitory fluoropyrimidines

BackgroundDihydropyrimidine dehydrogenase (DPD) is an enzyme that catabolizes 5-fluorouracil (5-FU). The effect of DPD inhibitory fluoropyrimidines (DIF) is presumably related to DPD activity. We studied the efficacy of DIF (tegafur + uracil [UFT], tegafur + gimeracil + osteracil [S-1 (TS-1®)]) relative to DPD activity, with other fluoropyrimidines as controls.MethodsThe efficacy of DIF relative to DPD activity was evaluated in 58 gastric cancer patients who received postoperative administration of fluoropyrimidines, consisting of DIF in 42 patients (UFT in 23; S-1 in 19) and non-DIF in 16 patients.ResultsIn patients with low DPD activity (under 40u2009U/mg protein), curative potential tended to be lower for DIF than for non-DIF, but the survival rate was the same for both. In patients with high DPD activity (40u2009U/mg protein or more), such a tendency was not detected. In a comparison between those treated with UFT and those treated with S-1, prognosis was better in the latter group, in spite of their predominance of lower curative potentials of B or C. In 27 patients with measurable lesions, a partial response (PR) or higher response occurred in 33% (5/15) of those with low DPD activity, and in 17% (2/12) of those with high DPD activity. In the patients with low DPD activity, non-DIF induced no change (NC) in 17% (1/6), and progressive disease (PD) in the rest. UFT induced PD in all 5 patients, while S-1 induced a response rate of 44% (7/16), with NC in 25% (4/16). In the patients with high DPD activity, on the other hand, non-DIF (n = 3) and UFT (n = 3) induced PD in all the patients, while S-1 induced PR in 33% (2/6) and NC or a higher response in 67% (4/6).ConclusionIt is recommended to use S-1 rather than UFT in patients with high DPD activity. Measurement of DPD was useful in drug selection.

Role of the liver in long-term control of drinking behavior, Na+ balance, and arterial pressure in Dahl rats

The role of postabsorptive mechanisms in long-term control of drinking behavior, Na+ balance, and arterial pressure was examined in Dahl salt-sensitive (DS) and salt-resistant (DR) rats. NaCl (0.15 M) was infused (0.5 ml/h) into either the inferior vena cava (IVC) or the portal vein (PV) for 7 days, and then 1.5 M NaCl was infused for 10 days. During 1.5 M infusion, the IVC group retained more Na+ than the PV group. Furthermore, in DS rats, mean arterial pressure was higher in the IVC group than in the PV group. Regardless of the strain and infusion route, 1.5 M infusion had no effect on volume of daily saline consumption. However, when the data for light and dark periods were analyzed separately, dark period saline consumption in the PV group was decreased by 1.5 M infusion but was not changed in the IVC group. These results indicate that, in Dahl rats, the postabsorptive mechanism plays a significant role in controlling long-term saline drinking behavior and Na+ balance and has a significant role in controlling arterial pressure in DS, but not DR, rats.The role of postabsorptive mechanisms in long-term control of drinking behavior, Na+ balance, and arterial pressure was examined in Dahl salt-sensitive (DS) and salt-resistant (DR) rats. NaCl (0.15 M) was infused (0.5 ml/h) into either the inferior vena cava (IVC) or the portal vein (PV) for 7 days, and then 1.5 M NaCl was infused for 10 days. During 1.5 M infusion, the IVC group retained more Na+ than the PV group. Furthermore, in DS rats, mean arterial pressure was higher in the IVC group than in the PV group. Regardless of the strain and infusion route, 1.5 M infusion had no effect on volume of daily saline consumption. However, when the data for light and dark periods were analyzed separately, dark period saline consumption in the PV group was decreased by 1.5 M infusion but was not changed in the IVC group. These results indicate that, in Dahl rats, the postabsorptive mechanism plays a significant role in controlling long-term saline drinking behavior and Na+ balance and has a significant role in controlling arterial pressure in DS, but not DR, rats.

Changes in arterial and portal perfusion in embolized and nonembolized hepatic lobes after portal vein embolization evaluated by helical computed tomography.

Abstract We evaluated the changes in hepatic arterial and portal perfusion in nonembolized as well as in embolized lobes after portal venous branch embolization (PVE) with dynamic helical computed tomography (CT). Six patients with hepatic malignancies, who underwent PVE prior to a subsequent hepatectomy, were the subjects of this study. We performed CT examinations before PVE and 2 weeks after PVE to make a volumetric analysis. At the same time, we performed single-location dynamic sequences after the injection of a 50-ml bolus of contrast medium, and we then created time–density curves from circular regions of interest drawn over the aorta, parenchyma of the right and left lobe of the liver, and spleen. We calculated the arterial perfusion index (ml/min per ml of tissue) and the portal perfusion index by dividing the maximum rate of enhancement of the liver before and after the splenic peak by the peak aortic enhancement. We then calculated the arterial and portal flows (ml/min) from the perfusion index and values of CT volumetry. In the right lobe, where the portal flow was occluded, the arterial perfusion index and flow increased significantly after PVE. In contrast, the arterial perfusion index and flow both decreased in the left lobe after PVE in a reverse response to the increase in the portal perfusion index and flow. The total arterial flow of the liver thus seemed to slightly increase; however, the change was not significant. By performing PVE an increased arterial perfusion was induced in the embolized lobe, with a concomitant decrease in arterial perfusion in the nonembolized lobe.

Acute responses of renal nerve activity to microgravity induced by free drop in anesthetized rats

To examine acute cardiovascular and autonomic responses to microgravity (microG), arterial pressure (AP), aortic flow velocity (AFV), central venous pressure (CVP), and renal nerve activity (RNA) were measured in anesthetized rats during 4.5 s of microG produced by free drop. A smooth and immediate reduction in gravity occurred during free drop, microG being achieved 100 ms after the start of the drop. Acute microG elicited an immediate and striking, but transient, decrease in RNA with no significant change in AP and AFV, but a significant decrease in CVP. The decrease in RNA lasted 2 s, then RNA recovered to the control level despite the G value remaining at < 0.001 for 4.5 s. The RNA decrease was attenuated or completely abolished by sinoaortic denervation, vagotomy, or sinoaortic denervation plus vagotomy. These results suggest that acute microG conditions stimulate sinoaortic and cardiopulmonary mechanoreceptors and suppress RNA.

Development of a flexible endoscopic (gastrofiberscopic) full-thickness suturing device: A triple arm bar suturing device

Flexible endoscopic closure devices currently available, such as those using clips, loops clips, and snares, are designed to grasp the mucosal surface from the gastric lumen. However, they do not appear capable of closing large incisions and perforations such as those made during natural orifice translumenal endoscope surgery(NOTES), and they do not suture a large incisions and perforations that require secure closure similar to that achieved by surgical suturing. Closure with a recently reported tissue-anchoring system is more secure than that by done by clipping, but is still not yet sufficiently secure. Moreover, repair is limited to the mucosal layer, so this method is not as secure as surgical full-thickness suturing. Therefore, there is a need for a flexible endoscopic full-thickness suturing device that sutures through the full thickness of the wall. To meet this demand, we have been developing a full-thickness suturing technology for flexible endoscopic surgery. This article describes the mechanism and structure of the triple arm bar suturing device, a flexible endoscopic full-thickness suturing device developed in our laboratory.

A CASE REPORT OF METASTATIC ADRENAL TUMOR FROM FIBROSARCOMA

A 50-year-old man who had been operated on for fibrosarcoma of the right upper arm, was admitted to the hospital because of a right adrenal tumor. Abdominal ultrasonography and computed tomography disclosed an abnormal tumor in the right adrenal gland. Bone scintigraphy showed metastatic bone tumor. The adrenal tumor was enlarging quickly, and so we considered that operation was indispensable. Under a suspicion of adrenal metastatic tumor, a right adrenalectomy was performed. Resected specimen showed a 5.4×4.4cm tumor, contained coagulating tissue. Histological findings were the same as those of fibrosarcoma of the right arm. Adrenal metastasis of fibrosarcoma was diagnosed. The metastatic adrenal tumor is rare, especially that of fibrosarcoma. Although the prognosis of metastatic adrenal tumor is usually poor, a better prognosis can be expected by positive excision of the tumor, if the original foci is well controlled and no other prominent metastasis is present.