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Biomedical subjects

K Hirayama

Publications and source records attributed to K Hirayama.

At least 73 records · Page 4Linked to original sources
PubMed2000

Esophageal carcinoma with nonrecurrent inferior laryngeal nerve.

Occurrence of a nonrecurrent inferior laryngeal nerve is quite rare. We present the case of a 70-year-old man with carcinoma of the esophagus. An abnormal right subclavian artery was detected preoperatively. This anomaly suggested that the right inferior laryngeal nerve branched directly from the vagal trunk. A carcinoma of the esophagus was resected, and lymph nodes were dissected. The right inferior laryngeal nerve was fully preserved, and the esophagus was primarily repaired.

Aged↗
PubMed2000

An electrospray-ionization mass spectrometry analysis of the pH-dependent dissociation and denaturation processes of a heterodimeric protein.

Electrospray ionization mass spectrometry (ESI-MS) was applied to the analysis of the dissociation and denaturation processes of a heterodimeric yeast killer toxin SMKT. The two distinct subunits of SMKT noncovalently associate under acidic conditions, but become dissociated and denatured under neutral and basic conditions. In order to understand the unique pH-dependent denaturation mechanism of this protein, a pH titration was performed by utilizing ESI-MS. The molecular ions of the heterodimer which possesses the highly ordered structure, were mainly observed below pH 4.6. However, the two subunits immediately dissociated at this pH. The spectra measured with various settings of the mass spectrometer indirectly demonstrated that the pH-dependent dissociation occurs in the liquid phase. The current result as well as the three-dimensional structure of SMKT suggest that the deprotonation of a specific carboxyl group triggers a cooperative dissociation process of this protein. In conclusion, the pH titration of a protein by ESI-MS is particularly effective, when the unfolding process or the biological function of the protein is related to the interaction with other molecules.

Fungal Proteins↗
PubMed2000

The role of probiotic bacteria in cancer prevention.

Colorectal cancer is one of the most important causes of cancer morbidity and mortality in western countries [1]. A myriad of healthful effects have been attributed to the probiotic lactic acid bacteria; perhaps the most controversial remains that of anticancer activity. There is no direct experimental evidence for cancer suppression in humans as a result of consumption of lactic cultures in fermented or unfermented dairy products. However, there is a wealth of indirect evidence, based largely on laboratory studies, in the literature and this will be summarised in the present paper.

Animals↗
PubMed2000

Juvenile muscular atrophy of distal upper extremity (Hirayama disease): focal cervical ischemic poliomyelopathy.

Hirayama disease is characterized by an initially progressive muscular weakness and atrophy of the distal upper limb(s) in adolescence, occurring predominantly in males, followed by spontaneous arrest within several years. Although the disease could be separated from motor neuron disease, some authors considered the illness to be a variant of degenerative motor neuron disease until the first autopsy case was reported which showed focal ischemic changes in the anterior horn of the lower cervical cord. Since then, many in Japan have recognized the disease as cervical ischemic poliomyelopathy; however, several authors in foreign countries did not or do not appreciate the pathologic findings of the disease, and still consider the illness a degenerative motor neuron disease. The pathology of the disease prompted neuroradiologic investigations, which have revealed dynamic changes of the cervical dural sac and spinal cord induced by neck flexion. The cause of these dynamic changes is unknown. However, as the number of patients is exceedingly large in Japan, there may be an ethnic factor.

Adolescent↗
PubMed2000

Effects of human intestinal flora on mutagenicity of and DNA adduct formation from food and environmental mutagens.

Although the intestinal flora is believed to have a critical role in carcinogenesis, little is known about the role of the human intestinal flora on the effects of mutagens in vivo. The aim of the present study was to address a possible role of the human intestinal flora in carcinogenesis, by exploiting human-flora-associated (HFA) mice. The capacity of human faeces to activate or inactivate 2-amino-3-methyl-3H:-imidazo[4,5-f]quinoline (IQ) and 2-nitrofluorene was determined using the Ames assay. Human faecal suspensions that were active in this regard were then selected and orally inoculated into germfree NMRI mice to generate HFA mice. HFA, germfree, conventionalized and conventional mice were administered IQ, 2-amino-9H:-pyrido[2,3-b]indole (2-amino-alpha-carboline; AAC) and 2-nitrofluorene. The activity of human intestinal flora against mutagens could be transferred into the mice. In comparing germfree mice and mice harbouring an intestinal flora, the presence of a flora was essential for the activities of faeces against mutagens. After administration of IQ and 2-nitrofluorene, DNA adducts were observed in the mice with a flora, while adducts were extremely low or absent in germfree animals. DNA adducts after AAC treatment were higher in germfree mice in some tissues including colon than in mice with bacteria. Differences in DNA adduct formation were also observed between HFA mice and mice with mouse flora in many tissues. These results clearly indicate that the intestinal flora have an active role in DNA adduct formation and that the role is different for the different chemicals to which the animals are exposed. The results also demonstrate that the human intestinal flora have different effects from the mouse flora on DNA adduct formation as well as in vitro metabolic activities against mutagens. Studies using HFA mice could thus provide much-needed information on the role of the human intestinal flora on carcinogenesis in vivo.

Adult↗
PubMed2000

Long-term consumption of a methionine-supplemented diet increases iron and lipid peroxide levels in rat liver.

Methionine is a protective factor against various types of liver damage, but excessive dietary methionine is hepatotoxic. Because the mechanisms of L-methionine-related hepatotoxicity are poorly understood, the effect of long-term excessive L-methionine intake on the metabolism of iron and antioxidants was studied in rat liver to determine whether oxidative stress is involved. Wistar male rats were fed either an L-methionine-supplemented (16.0 g/kg) diet or a control diet for 1, 3, 6 and 9 mo. The growth rate of L-methionine-supplemented rats was significantly slower than that of controls. Iron, ferritin and thiobarbituric acid-reactive substances (TBARS) levels in the liver were greater in supplemented rats than in controls. Serum iron and transferrin levels were significantly lower in L-methionine-treated rats compared with controls. Serum ferritin did not differ between the two groups. Hepatic glutathione peroxidase activity, catalase activity and total glutathione concentrations were higher in rats fed the L-methionine-supplemented diet at 1 and 3 mo, but not at 6 and 9 mo. These results indicate that long-term consumption of excess L-methionine by rats may affect primarily iron metabolism rather than the antioxidant defense system and, consequently, induce an accumulation of iron.

Animals↗
PubMed2000

Prevalence of Japanese dialysis patients with an A-to-G mutation at nucleotide 3243 of the mitochondrial tRNA(Leu(UUR)) gene.

BACKGROUND: A high prevalence of an A-to-G mutation at nucleotide 3243 of the mitochondrial genome in patients with diabetes mellitus (DM) and/or deafness has been reported previously. We investigated the prevalence of this mutation in Japanese dialysis patients with associated DM and/or deafness. METHODS: We studied 106 dialysis patients with DM, 26 with DM and deafness, and 26 with deafness alone, using peripheral leucocytes to detect an A-to-G transition at nucleotide 3243 of the mitochondrial gene. RESULTS: We identified this transition in 1 of 26 patients with DM and deafness. None of the 106 DM or 26 dialysis patients with deafness but no DM was positive for this mutation. A 42-year-old male patient on continuous ambulatory peritoneal dialysis (CAPD) who carried this mutation had a 20-year history of sensory hearing loss as well as hypertrophic cardiomyopathy. CONCLUSION: We found that a mitochondrial gene mutation at nucleotide 3243 was present in one dialysis patient with NIDDM and deafness. The prevalence of this mutation was found to be below 1% in diabetic end-stage renal disease patients in Japan.

Adult↗
PubMed2000

Cytokines and T-cell responses in superantigen-related glomerulonephritis following methicillin-resistant Staphylococcus aureus infection.

BACKGROUND: We have previously reported that 10 patients who developed glomerulonephritis (GN) in association with methicillin-resistant Staphylococcus aureus (MRSA) infection showed a marked increase in DR+CD4+ and DR+CD8+ subsets of T cells and in T cells expressing several T-cell receptor (TCR) V beta+cells, perhaps representing V beta-specific T-cell activation by MRSA-derived superantigens (Kidney Int 1995; 47: 207-216). In this study we examine cytokine levels, T-lymphocyte subsets, natural killer NK cells, memory T cells, and the expression of IL-2 receptors in order to better understand the role of bacterial superantigens and cytokines in the pathogenesis of MRSA-associated GN. METHODS: Twenty-two patients with MRSA infection who later developed GN caused by staphylococcal enterotoxin were evaluated immunologically in comparison with patients whose MRSA infection was not followed by GN (non-GN group) and normal individuals. RESULTS: Among peripheral lymphocytes, the frequency of T cells expressing several TCR V betas, especially V beta 5-family TCR, was higher in the GN group than in both the non-GN group and the normal healthy control group. GN patients also showed increased serum levels of several cytokines, including tumour necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), IL-2, IL-6, IL-8, and IL-10, which have been implicated in the onset of nephritis. Memory cells, and IL-2 receptors also were elevated in the GN group. CONCLUSION: These results suggest that T cells activated by MRSA-derived staphylococcal enterotoxins and subsequent production of cytokines may play an important role in the pathogenesis of MRSA-associated GN.

Adult↗
PubMed2000

Extraocular muscle responses to high dose intravenous methylprednisolone in myasthenia gravis.

Three patients with generalised myasthenia gravis and three with ocular myasthenia gravis received two to five courses of high dose intravenous methylprednisolone because of the failure of standard immunomodulating therapies. Changes in myasthenic signs were assessed using a four step system for grading muscle weakness and fatiguability in 10 test items. Although a brief and modest amelioration was found from day 1 to day 2 after the initial infusion in two patients with generalised myasthenia gravis, all three experienced a prolonged phase of worsening followed by improvement before the next course. Conversely, for two of the patients with ocular myasthenia gravis, a transient but dramatic improvement of ptosis and ocular immobility was noted from 90 minutes to 5 hours after initiating the first infusion, followed by mild or no exacerbation. This 3 hour improvement may be related not only to possible differences in the neuromuscular junction, but also to corticosteroids unmasking the central adaptation for the peripheral ocular muscle weakness by increasing the acetylcholine release.

Acetylcholine↗
PubMed2000

Localized amyloidosis in canine mammary tumors.

Histopathologic and immunohistochemical examinations were performed on localized amyloidosis associated with mammary tumors in two dogs. These tumors were identified as adenoma and adenocarcinoma. An acellular, amorphous pale eosinophilic material (amyloid) was observed in the lumina of acini lined by neoplastic cells and in the stroma of the tumors. Concentrically laminated pale eosinophilic bodies (corpora amylacea) were also found in the lumina of the acini. Amyloid and corpora amylacea stained positively with Congo red with and without 5% potassium permanganate pretreatment and revealed a green birefringence under polarized light. Corpora amylacea showed an occasional Maltese-cross pattern. Immunohistochemically, amyloid and corpora amylacea usually stained positively with anti-bovine alpha-casein antibody but negatively with anti-human amyloid AA, anti-bovine kappa-light and lambda-light chains, anti-human lactoferrin, anti-human transferrin, anti-human secretory component, and anti-human polyglucosan antibodies. These findings suggested that the amyloid deposition in these canine mammary tumors was related to lactating casein.

Adenocarcinoma, Papillary↗
PubMed2000

Systemic kappaAL amyloidosis associated with bovine leukocyte adhesion deficiency.

Histopathologic and immunohistochemical examinations were conducted on a 5-year-old Holstein-Friesian cow with systemic kappaAL amyloidosis associated with bovine leukocyte adhesion deficiency. Amyloid deposits were present in the perivascular and intercellular spaces of the visceral organs, such as the liver, kidneys, pancreas, adrenal glands, and upper alimentary tract. Amyloid was stained positively with Congo red with or without 5% potassium permanganate pretreatment and had green birefringence observed under polarized light. Immunohistochemically, amyloid reacted strongly against anti-bovine IgG (H+L) and anti-bovine kappa-light chain and reacted weakly against bovine X-light chain antibodies but was negative for anti-human amyloid AA antibody. This is the first description of AL amyloidosis immunohistochemically related to immunoglobulin kappa-light chains of precursor protein in cattle.

Amyloid↗
PubMed2000

A pleomorphic adenoma of the lacrimal gland in a dog.

A 13-year-old female mongrel dog had a pleomorphic adenoma of the lacrimal gland in the right upper orbit. The tumor measured 3.8 x 3.0 x 3.3 cm, appeared white, round, and firm, and pressed the right globe and surrounding tissues. Histopathologically, the tumor had a thin connective tissue capsule and was composed of tubules with two cell types, some resembling luminal epithelial cells making up the tubular structures and the other of myoepithelial cells. Epithelial tubules were disposed in an adenomatous fashion and separated from each other by proliferating pleomorphic myoepithelial cells. Immunohistochemically, large numbers of the luminal epithelial cells revealed an immunopositive reaction against keratin/cytokeratin (AE1/AE3), and some epithelial cells reacted against cytokeratin 14. Spindle-shaped myoepithelial cells revealed an immunopositive reaction against cytokeratin 14, alpha-smooth muscle actin, and vimentin. A small number of myoepithelial cells reacted against desmin. S-100 protein immunopositivity was frequently found in luminal epithelial cells and rarely in the pleomorphic myoepithelial cells. Glial fibrillary acidic protein positivity was commonly found in myoepithelial cells, myxoid matrices, and intracystic materials, but not in luminal epithelial cells.

Actins↗
PubMed2000

Juvenile muscular atrophy of distal upper extremity (Hirayama disease).

This disease is characterized by initially progressive muscular weakness and wasting of the distal upper limb(s) in young people predominantly in men, followed by a spontaneous arrest within several years. This disease has been thought to be separate from motor neuron diseases, yet some authors still consider the illness a variant of motor neuron disease. However, the pathological evidence of ischemic changes in the lower cervical anterior horn should facilitate differentiation of the disorder from degenerative motor neuron disease. Recent radiological investigations proved compressive flattening of the lower cervical cord due to forward displacement of the cervical dural sac and spinal cord induced by neck flexion. These findings suggest that sustained or repeated neck flexion may cause ischemic changes in the cervical anterior horn. Application of a cervical collar to minimize neck flexion prevents progressive muscular weakness in an early stage of the disease.

Arm↗
PubMed2000

Sensory ataxic dominant neuropathy associated with polyarteritis nodosa.

A 68-year-old man with sensory ataxic dominant neuropathy associated with polyarteritis nodosa (PAN) had deep sensory disturbance with unsteady gait and absence of the Achilles tendon reflex. Examination revealed weight loss, elevated CRP level, negative antineutrophil cytoplasm antibodies, decreased M-wave amplitude in the peroneal motor nerve and absence of action potentials in the sural sensory nerve. Sural nerve biopsy revealed a marked loss of myelinated fibers, myelin ovoid formation and necrotizing angiitis of large epineurial arterioles. Renal biopsy revealed global and/or segmental necrotizing angiitis in glomeruli, but not in the arcuate artery. These pathological findings were distinct from those of PAN, particularly microscopic polyangiitis (MPA). Treatment with a steroid improved the deep sensory disturbance, unsteady gait, and CRP level. This case is similar to ataxic neuropathy which can arise from various disorders. This is the first report of a case of sensory ataxic dominant neuropathy associated with MPA in PAN.

Action Potentials↗
PubMed2000

[A case of primary intrapulmonary thymoma: its entity and the problem of lymph node dissection].

Primary intrapulmonary thymomas are defined as primary thymomas arising in an intrapulmonary location without an associated mediastinal component, and they are very rare. A total of 20 cases have been reported only sporadically in the English literature since 1951. We reported the case of 41-year-old woman who had a 3.5 x 3.0 x 3.0 cm lower right lobe mass with nodal metastasis that extended over the left atrium. We also summarized the clinicopathological features of a total of 21 cases and discussed the problems involved with diagnosis, pathogenesis and treatment. Knowledge of the biological behavior of primary intrapulmonary thymomas is limited because of their rarity. In particular, the issue of the need for lymph node dissection has not been adequately discussed. In this case, pathohistological examination revealed that the routes of lymphatic spread and the sites of noda metastases from primary intrapulmonary thymoma resemble those of primary lung cancer. Therefore, systematic mediastinal lymph node dissection according to the lymph node map for primary lung cancer should be recommended for malignant cases.

Adult↗
PubMed1999

'Thumb localizing test' for detecting a lesion in the posterior column-medial lemniscal system.

A proprioception examination, called the 'thumb localizing test' (TLT), is described as a technique for testing 'limb localization'. With the patient's eyes closed, the examiner positions one of the patient's upper limbs (fixed limb) and asks him to pinch the thumb of that limb with the opposite thumb and index finger (reaching limb). The findings for 221 patients (423 limbs) show that: there were TLT deficits when the limb contralateral to the cerebral lesion or ipsilateral to the peripheral nerve lesion was the fixed limb, but not when the fixed limb became the reaching limb; that the deficits of limb localization found by the TLT were strongly correlated with deficits of deep or discriminative perceptions such as sense of joint position and movement and tactile cutaneous localization, but uncorrelated with sensory deficits of pain and temperature; that deficits of limb localization were apt to arise from lesions in the posterior column-medial lemniscal system at various levels in the peripheral nerves, cervical cord, brainstem, thalamus or parietal lobe; and that impairment of limb localization and other deep or discriminative sensations were occasionally dissociated. The TLT is easily done at the patient's bedside and can detect a lesion in the posterior column-medial lemniscal system. Moreover, it provides the means to examine the perceptual deficits using a motor task of the opposite limb.

Adolescent↗