WHAT KIND OF BENEFIT DO WE EXPECT FOR PERORAL PANCREATOSCOPY IN THE DIAGNOSIS OF INTRADUCTAL PAPILLARY MUCINOUS TUMOR OF THE PANCREAS?

Intraductal papillary mucinous tumor (IPMT) of the pancreas is characterized by slow growth and a relatively favorable prognosis, however, invasive cancer originating in an IPMT is associated with a poor prognosis. Although various parameters in imaging modalities have been advocated to differentiate between benign IPMN and malignant ones, it is not easy to obtain definite diagnosis based on these parameters. Peroral pancreatoscopy (POPS) allows a clear and direct visualization of the pancreatic duct, providing useful information regarding tumor nature in IPMT. The authors have studied the usefulness of POPS in the diagnosis of IPMT. Nevertheless, its usefulness is not necessarily widely accepted and the significance of POPS is still controversial. In this review, the authors intended to address the diagnostic value of POPS and to clarify its role in the diagnosis of IPMT. The authors think treatment of IPMT can be improved by introducing POPS because the determination of surgical procedure as well as the area of resection based on the preoperative diagnosis of the involvement of the main pancreatic duct and branch duct is inevitable.     

Improved formulations of antisense oligodeoxynucleotides using wrapped liposomes.

Previously, we demonstrated that wrapping dextran fluorescein anionic/cationic lipid complexes with neutral lipids produced a stable formulation that markedly increased the duration of the compound in plasma after intravenous administration to rats. The improved drug-delivery properties of the wrapped liposomes (WL) relative to other formulations suggested that this technology could offer important advantages for the administration of other polyanionic drugs, including antisense oligodeoxynucleotides (ODN). In the present study, we investigated the value of WL for formulating fluorescence-labeled phosphorothioated ODN (F-ODN). WL encapsulating F-ODN/cationic lipid complexes were prepared efficiently using similar methodology to that used in our earlier study. Studies confirmed that these WL were stable in vitro. Following intravenous administration to mice, free F-ODN and naked F-ODN/cationic lipid complexes were rapidly eliminated whereas administration of the WL resulted in high blood concentrations of drug that were maintained for several hours. Additional studies were conducted in mice that were inoculated with tumor cells (Caki-1 xenograft model, human kidney); in these experiments, intravenous administration of WL delivered 13 times more F-ODN to the tumor site than achieved after injection of free F-ODN.     

IMPROVED BALLOON‐TIPPED TRANS‐ANAL ILEUS TUBE

Background: For management of bowel obstruction due to colorectal cancer, endoscopic trans‐anal decompression technique has been first reported by Lelcuk et al. in 1986 using balloon dilatation technique. Since then, various types of trans‐anal decompression tubes have been clinically used for patients suffering from left side obstructing colorectal cancer as an emergent decompressing device. At present, two types of trans‐anal ileus tube (trans‐anal decompression tube) have been available for clinical use, but they have two main problems that are late colon perforations caused by the tip of the tube and tube obstruction by stool. Methods: Analysis on three late colon perforations experienced with the use of conventional devices drew possible improvements to make a trans‐anal ileus tube less harmful. To overcome the pitfalls inherent to conventional tubes, the author has developed an improved trans‐anal ileus tube with a balloon installed at the very end of the tube (‘balloon‐tipped type’) made of silicone, measuring 1200 or 1700 mm in total length and 22 Fr in outer diameter. It has been used for 12 cases with obstructing colorectal cancer etc. and its outcomes were compared with those obtained by the use of conventional trans‐anal ileus tube. Results: No late perforations have been encountered, but tube obstruction did occur in one of 12 cases. Conclusion: The new trans‐anal ileus tube with a balloon installed at the tip of ileus tube is considered to be safer and especially effective in preventing late colon perforation and tube obstruction.     

The role of intraoperative monitoring of oculomotor and trochlear nuclei -safe entry zone to tegmental lesions.

OBJECTIVE: A safe entry zone to tegmental lesions was identified based on intraoperative electrophysiological findings, the compound muscle action potentials (CMAP) from the extraocular muscles, and anatomic considerations. This entry zone is bordered caudally by the intramesencephalic path of the trochlear, laterally by the spinothalamic tract, and rostrally by the caudal margin of the brachium of the superior colliculus. METHODS: Four intrinsic midbrain lesions were operated upon via the safe entry zone using the infratentorial paramedian supracerebellar approach. All lesions involved the tegmentum and included an anaplastic astrocytoma, a metastatic brain tumor, a radiation necrosis, and a cavernous angioma. CMAP were bilaterally monitored from the inferior recti (for oculomotor function) and superior oblique (for trochlear nerve function) muscles. RESULTS: In three of four cases, CMAP related to the oculomotor nerve were obtained upon stimulation at the cavity wall after removal of the tumor. Stimulation at the surface of the quadrigeminal plate, however, did not cause any CMAP response. Using this monitoring as an indicator, the lesions were totally removed. CONCLUSIONS: In the surgery of tegmental lesions, CMAP monitoring from extraocular muscles is particularly helpful to prevent damage to crucial neural structures during removal of intrinsic lesions, but less so to select the site of the medullary incision. The approach via the lateral part of the colliculi is considered to be a safe route to approach the tegmental lesions.     

Immunohistochemical and immunoelectron microscopical characterization of cerebrovascular and senile plaque amyloid in aged dogs'' brains

Immunohistochemical and immunoelectron microscopical studies were carried out on 28 aged dogs' brains. Amyloid deposits were seen in the arteries and capillaries in the leptomeninges and in superficial areas of the cortices in 19 (67.9%) of the 28 dogs (10-22 years of age). Immunohistochemically, these amyloid deposits were reactive for anti-beta/A4 antibody. Additionally, a variable number of parenchymal deposits with diffuse beta/A4-immunoreactivity (diffuse plaques) was also noted throughout the cerebral cortex in 24/28 dogs (85.7%). However, these plaque lesions were undetectable in Congo red staining. Electron microscopically, amyloid fibrils, measuring 10 nm in width, were located mainly in the tunica media of the arteries, and in less involved vessels they tended to be present among collagen fibres in the adventitia and smooth muscle cells in the outer layer of the media. The plaque lesions appeared to contain sparse aggregations of amyloid fibrils. In immunoelectron microscopical examinations, all amyloid fibrils in both blood vessels and plaques were selectively labelled by gold particles. These findings indicate that aged dogs can provide a useful experimental model for research into the beta/A4-type of cerebral amyloidosis commonly seen in Alzheimer's disease.     

Endocrine and hemodynamic responses to total body hyperthermia in humans

We investigated effects of total body hyperthermia (TBH) on endocrine and hemodynamic responses. A total of five treatments were performed in five patients with gastric cancer under neuroleptanesthesia with morphine followed by 0.2 to 0.4% enflurane. TBH was extracorporeally induced with veno-venous shunt incorporating with heat exchanger to keep their temperature between 41.5 degrees C and 42.0 degrees C for three hours. The patients were administered angiotensin to maintain tumor blood flow. Lactated Ringer's solution was administered at the rate of 10 to 15 ml.kg-1.hr-1 for five hours. Plasma cortisol levels decreased significantly to about one third of the control value after heating and the levels recovered to the control value after cooling. Plasma norepinephrine level increased significantly to about 7 to 9 times the control value following TBH, but this hormonal response was insufficient to reveal marked direct hemodynamic effects. The magnitude of fall in SVR was more significant in spite of the administration of angiotensin. Cardiac index increased significantly to about 2.0 to 2.6 fold of control value, but mean arterial blood pressure (MAP) decreased significantly to about two thirds to four fifths of the control value. Morphine relieved the hormonal response in ACTH and cortisol strongly, but morphine suppressed hemodynamics by decreasing SVR. Neither norepinephrine released from sympathetic nerve endings nor even 50 to 200 ng.kg-1.min-1 of angiotensin administered failed to restore SVR or MAP during hyperthermia.