Positron emission tomography with 4-[18F]fluoro-L-m-tyrosine in MPTP-induced hemiparkinsonian monkeys

PET imaging studies with 4-[¹⁸F]fluoro-L-m-tyrosine (FMT) in normal macaca monkeys showed selective accumulations of radioactivity in the striatum with time. In monkeys rendered hemiparkinsonian by intracarotid infusion of l-methyl-4-phenyl-l,2,3,6-tetrahydropyridine (MPTP), FMT uptake was eliminated in the lesioned striatum. FMT-PET studies were able to detect dopaminergic terminals in both normal and hemiparkinsonian monkeys, and clearly showed a reduction in aromatic L-amino acid decarboxylase (AAAD) activities in the MPTP-lesioned striatum. These results show that FMT is promising as a PET tracer for the evaluation of central dopaminergic systems in parkinsonism.     

Preventive effect of simultaneously infused lipid emulsion against thrombophlebitis during postoperative peripheral parenteral nutrition

A prospective, randomized study was conducted to determine whether simultaneous infusion of lipid emulsion with an amino acid-dextrose-electrolyte solution would reduce the incidence of thrombophlebitis (TP) during postoperative peripheral parenteral nutrition (PPN). Thirty patients who had undergone gastric resection for adenocarcinoma were randomly divided into two groups according to whether they were infused with 10% lipid emulsion (group A) or 5% glucose solution (group B) simultaneously with the amino acid-glucose solutions. The total osmolarity of the infusion solutions in each group was 853 mOsm/l. The incidence of complications due to TP, namely, redness and/or edema beneath the cannula insertion site and/or pain, was investigated. There were no differences in the background characteristics of the patients in groups A and B, except regarding concurrent resection of other organs (P=0.03). The incidence of edema in group A was significantly lower than in group B on postoperative days 2 and 4, although there was no difference in the incidence of redness and pain between the two groups. These findings suggest that the simultaneous infusion of lipid emulsion has a preventive effect against TP during postoperative PPN, and may be a practical means of providing PPN after gastrointestinal surgery.     

Involvement of α-adrenoceptors in the endothelium-dependent depression of noradrenaline-induced contraction in rat aorta

The involvement of endothelium-derived nitric oxide (NO) in the depressant action of the endothelium on noradrenaline-induced contractions and characterization of the receptor involved in the release of NO were studied using rat aorta. The noradrenaline-induced contraction was significantly potentiated by endothelium removal and in the presence of N^G-nitro-L-arginine (L-NNA) or N^G-monomethyl-L-arginine (L-NMMA). The contraction induced by phenylephrine was also potentiated in the presence of L-NNA. Clonidine could induce contraction only in endothelium-denuded preparations or in the presence of L-NNA. The potentiating action of L-NNA on noradrenaline-induced contractions could also be observed in the presence of yohimbine or rauwolscine, although dose-response curves were shifted to the right. The depression of noradrenaline-induced contractions observed in the presence of the endothelium was increased by repeated stimulation. The depression was prevented by L-NNA and this effect was reversed by L-arginine. These results indicate the possibility that NO can be released through stimulation of α₁- and α₂-adrenoceptors on the endothelium and depresses noradrenaline-induced contractions of smooth muscle, although the contribution of the respective adrenoceptors remains to be investigated. The release of NO was increased when the stimulation was applied repeatedly.     

Renal oncocytomatosis in a long-term hemodialysis patient treated by laparoscopic surgery

A 50-year-old female, who had been on maintenance hemodialysis for 22 years, consulted our clinic because of a left renal mass detected incidentally by ultrasonography. Computed tomography (CT) demonstrated a solid hypervascular mass, suggesting a renal cell carcinoma (RCC), in the left atrophic kidney. Left hand-assisted laparoscopic nephrectomy (HALN) was performed. The histopathological diagnosis was renal oncocytomatosis. Renal oncocytomatosis in a long-term hemodialysis patient is extremely rare. We report the first case of renal oncocytomatosis in a long-term hemodialysis patient treated with hand-assisted laparoscopic nephrectomy.     

Effects of changes in skiing posture on the kinetics of the knee joint

This study was performed to investigate the effects of changes in the skiing posture on mechanical stress across the knee joint. The aim of the present study was to establish a safer form of skiing for the prevention of injury to the anterior cruciate ligament of the knee (ACL). Ten healthy volunteers were placed on a force plate on an artificial slope, and assumed forward and backward bending postures with a single leg by changing their centre of gravity. The knee flexion angles were limited to approximately 30° by orthotics in each posture. Joint moments of the lower extremity were analyzed using a motion analysis system, and the muscle activities of the lower extremity were recorded by EMG and digitised to integrated EMG in each posture. In addition, extrusion of the lower leg by the boot was measured using a force sensor sheet inserted behind the calf. We found that the extension moment of the hip and ankle joints, and muscular activity of the hamstrings were increased in forward bending, whereas the extension moment of the knee and muscular activity of the quadriceps were decreased. Conversely, the muscular activity of the quadriceps, the flexion moment of the hip, extension moment of the knee joint, and pressure of the boot were increased in backward bending, whereas muscular activity of the hamstrings was decreased. The dependency on the hamstrings increased in forward bending in a skiing posture on a slope with slight knee flexion. Therefore, forward bending seemed to be an advantageous posture for the prevention of ACL injury. Conversely, in a backward bending skiing posture, the extension moment of the knee joint produced by muscle contraction of the quadriceps also increased imbalance in the hamstrings. The results of this study suggest that the internal force exerted by the quadriceps, in addition to the passive factor of extrusion of the lower leg by the boot, may contribute to non-contact ACL injury in a backward bending posture while skiing.     

Malignant Schwannoma Arising in Patients with Von Recklinghausen's Disease: Report of Two Cases and the Comparison of Mast Cells between Benign and Malignant Portions

We described two cases of malignant schwannoma arising in patients with von Recklinghausen's disease and examined the mast cells infiltrated into histologic sections. One of the two cases histologically revealed apparent mast cell infiltration in some areas of malignant schwannoma as well as in the benign neurofibroma. The malignant lesion demonstrated significantly increased percentages of degranulated mast cells over the benign lesion using FITC-avidin staining. In an electron microscopic study, mast cells in the malignant lesion displayed empty granules, piecemeal degranulation, and canaliculi structures suggesting activation. These findings were not observed in the benign lesion. The other patient histologically showed no mast cells in the malignant lesion, although the benign neurofibroma in the patient disclosed numerous mast cells. The first patient had neither recurrence nor distant metastasis. On the other hand, the second patient without mast cells in the histology had multiple distant metastases. These findings raise questions about the role of mast cells in malignant schwannoma.     

Molecular pathomechanism of distal myopathy with rimmed vacuoles]

Distal myopathy with rimmed vacuoles (DMRV) and hereditary inclusion body myopathy (HIBM) are genetically identical autosomal recessive muscle disorders caused by mutations in the GNE gene. This gene encodes a bifunctional protein with UDP-GlcNAc 2-epimerase and ManNAc kinase activities that catalyze the rate limiting step and the succeeding step, respectively, in the sialic acid biosynthetic pathway. V572L mutation is the most prevalent among Japanese DMRV patients and accounts for about 60% of mutant alleles. Clinical spectrum of DMRV/HIBM seems to be wider than previously thought in terms of both the severity of the disease and the range of affected organs. There are rare asymptomatic homozygotes with missense GNE mutations, indicating the presence of mitigating factors. Surprisingly, more than 10% of the patients had a variety of cardiac abnormalities, suggesting that skeletal muscle may not be the only organ involved. Studies on recombinant GNE demonstrate a loss-of-function nature of the missense mutations identified. Patients' cells show decreased sialylation status which can be recovered by adding GNE metabolites, such as ManNAc and NeuAc. This indicates the possibility of developing a therapy for DMRV/HIBM by giving these metabolites to patients although we have to await the model mice that are currently being produced at several laboratories.     

A Case of Pachydermoperiostosis with Watery Diarrhea,Giant Gastri Rugae,and Endocrine Disorder

Abstract: A 31-year-old man, cook, who had had persistent watery diarrhea for about a month visited our hospital. He had already been diagnosed as having pachydermoperiostosis. An examination of the upper gastrointestinal tract revealed that he had giant gastric rugae. The histology was compatible with hypertrophic gastritis accompanied with marked hyperplasia of the fundic gland and foveolar epithelia. The output of gastric juice was high in volume, although its acidity normal. The barium transit time of the small intestine was reduced to 15 minutes. His diarrhea was, thus, considered to be induced by gastrointestinal hyperfunction. The patient's glucose tolerance was abnormal and basal Cortisol secretion level was high. Pachydermoperiostosis has been the focus of attention for skin and bone changes, and the frequency of this disease with endocrine disorders seems rather high, but accompanying gastrointestinal disorders have so far not often been reported in Japan. The results of our investigation strongly suggest that pachydermoperiostosis is a systemic disease.     

Hypoxia-induced ABR change and heat shock protein expression in the pontine auditory pathway of young rabbits

The auditory brainstem response (ABR) was compared with the immunohistochemical expression of heat shock protein (HSP-72) and microtubule-associated protein 2 (MAP-2) of the brainstem auditory pathway in young rabbits subjected to hypoxic stress. Severe hypoxia for 2 h produced significant prolongation and decreased amplitude of the later component of ABR. HSP-72 expression was distinctly increased in the cochlear nucleus, but there was less induction in the inferior colliculus under severe hypoxia. MAP-2 immunostaining of neuropiles in the inferior collicular nucleus was decreased slightly after severe-long hypoxia, but cytoplasmic staining did not change. The present ABR change, which was produced by brainstem hypoxia-ischemia and acidosis, may be due to the neural cytoarchitectural derangement and less induction of stress proteins in the upper brainstem.