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Biomedical subjects

M Yamagata

Publications and source records attributed to M Yamagata.

At least 73 records · Page 4Linked to original sources
PubMed1998

The contribution of lactic acid to acidification of tumours: studies of variant cells lacking lactate dehydrogenase.

Solid tumours develop an acidic extracellular environment with high concentration of lactic acid, and lactic acid produced by glycolysis has been assumed to be the major cause of tumour acidity. Experiments using lactate dehydrogenase (LDH)-deficient ras-transfected Chinese hamster ovarian cells have been undertaken to address directly the hypothesis that lactic acid production is responsible for tumour acidification. The variant cells produce negligible quantities of lactic acid and consume minimal amounts of glucose compared with parental cells. Lactate-producing parental cells acidified lightly-buffered medium but variant cells did not. Tumours derived from parental and variant cells implanted into nude mice were found to have mean values of extracellular pH (pHe) of 7.03 +/- 0.03 and 7.03 +/- 0.05, respectively, both of which were significantly lower than that of normal muscle (pHe = 7.43 +/- 0.03; P < 0.001). Lactic acid concentration in variant tumours (450 +/- 90 microg g(-1) wet weight) was much lower than that in parental tumours (1880 +/- 140 microg/g(-1)) and similar to that in serum (400 +/- 35 microg/g(-1)). These data show discordance between mean levels of pHe and lactate content in tumours; the results support those of Newell et al (1993) and suggest that the production of lactic acid via glycolysis causes acidification of culture medium, but is not the only mechanism, and is probably not the major mechanism responsible for the development of an acidic environment within solid tumours.

Animals↗
PubMed1998

Endoscopic papillary balloon dilation for the management of common bile duct stones: experience of 226 cases.

BACKGROUND AND STUDY AIMS: Endoscopic sphincterotomy is a widely accepted technique for the treatment of patients with common bile duct stones. However, it is still associated with occasional complications. The recently developed technique of endoscopic papillary balloon dilation seems to be a safe and effective procedure, and to have great potential for replacing endoscopic sphincterotomy. However, few reports have been published on the use of this technique for bile duct stones. The present study was undertaken to evaluate its safety and efficacy. PATIENTS AND METHODS: Endoscopic papillary balloon dilation was used to remove common bile duct stones in 226 consecutive patients including 41 patients of ASA classification III/IV, 41 elderly patients (> 80 years) 24 with liver cirrhosis, and 86 with periampullary diverticulum. After dilation of the papilla with a balloon diameter of 8 mm, the stones were retrieved. RESULTS: In conjunction with the use of a mechanical or/and electrohydraulic lithotriptor in 79 patients (35%) with large stones (> 10 mm in diameter), clearance of the common bile duct was achieved in 225 of 226 patients (99%) without serious complications, such as hemorrhage or severe pancreatitis; mild (n = 13) or moderate (n = 2) pancreatitis occurred in 7% of cases. CONCLUSIONS: Endoscopic papillary balloon dilation is a safe and effective technique for the treatment of common bile duct stones, even in high-risk patients.

Adult↗
PubMed1998

Double stapling method of anastomosis after esophagectomy with endoscopic stapler to prevent postoperative stricture.

To prevent stricture of an anastomotic site after operation of esophageal cancer, a new surgical technique, the "double-stapling method," was designed and applied clinically to 29 patients. According to the surgical technique, an automatic suture device for endoscopy was inserted from the side of the lesser curvature of the stomach to the esophageal side after performing end-side anastomosis between the esophagus and the stomach tube using a conventional circular anastomotic device to perform anastomosis between the anterior wall of the esophagus and the posterior wall of the stomach tube. As a result, a conventional anastomotic site, which was a plane (two dimensional), was transformed into a three-dimensional configuration. In the postoperative measurement of the anastomotic site using a measurement forceps, the inner diameter of the site was 8.6+/-3.1 mm in the circular group, while it was 17.2+/-4.5 mm in the DS group, showing a significant difference (p < 0.0001). Minor leakage was observed in three patients as a postoperative complication, but no postoperative hemorrhage occurred.

Anastomosis, Surgical↗
PubMed1998

Analysis of localization of mutated tissue-nonspecific alkaline phosphatase proteins associated with neonatal hypophosphatasia using green fluorescent protein chimeras.

Hypophosphatasia is associated with a defect of the tissue-nonspecific alkaline phosphatase (TNSALP) gene. The onset and clinical severity are usually correlated in hypophosphatasia; patients with perinatal hypophosphatasia die approximately at the time of birth. In contrast, we describe a male neonatal patient with hypophosphatasia who had no respiratory problems and survived. He was compound heterozygous for the conversion of Phe to Leu at codon 310 (F310L) and the deletion of a nucleotide T at 1735 (delT1735), causing the frame shift with the result of the addition of 80 amino acids at the C-terminal of the protein. Because the C-terminal portion of TNSALP is known to be important for TNSALP to bind to the plasma membrane, the localization of wild-type and mutated TNSALP proteins was analyzed using green fluorescent protein chimeras. The expression vectors containing the complementary DNA of fusion proteins consisting of signal peptide, green fluorescent protein, and wild-type or mutated TNSALP, caused by delT1735 or F310L mutation, were introduced transiently or stably in Saos-2 cells. The delT1735 mutant failed to localize at the cell surface membrane, whereas the wild-type and the F310L mutants were located in the plasma membrane and cytoplasm. The assay for enzymatic activity of TNSALP revealed that the delT1735 mutant lost the activity and that the F310L mutant exhibited an enzymatic activity level that was 72% of the normal level. The F310L mutation was also detected in another neonatal patient with relatively mild (nonlethal) hypophosphatasia (reported in J Clin Endocrinol Metab, 81:4458-4461, 1996), suggesting that residual ALP activity of the F310L mutant contributes to the less severe phenotype. The patient is unique, with respect to a discrepancy between onset and clinical severity in hypophosphatasia.

Alkaline Phosphatase↗
PubMed1998

Sensory nerve fibres from lumbar intervertebral discs pass through rami communicantes. A possible pathway for discogenic low back pain.

It has been thought that lumbar intervertebral discs were innervated segmentally. We have previously shown that the L5-L6 intervertebral disc in the rat is innervated bilaterally from the L1 and L2 dorsal root ganglia through the paravertebral sympathetic trunks, but the pathways between the disc and the paravertebral sympathetic trunks were unknown. We have now studied the spines of 17 rats to elucidate the exact pathways. We examined serial sections of the lumbar spine using immunohistochemistry for calcitonin gene-related peptide, a sensory nerve marker. We showed that these nerve fibres from the intervertebral disc ran through the sinuvertebral nerve into the rami communicantes, not into the corresponding segmental spinal nerve. In the rat, sensory information from the lumbar intervertebral discs is conducted through rami communicantes. If this innervation pattern applies to man, simple decompression of the corresponding nerve root will not relieve discogenic pain. Anterior interbody fusion, with the denervation of rami communicantes, may be effective for such low back pain.

Animals↗
PubMed1998

Fracture-dislocation of the fifth lumbar vertebra. A new classification.

We have studied fracture-dislocation of the fifth lumbar vertebra in seven patients and reviewed 50 previously reported cases. Based on this information, we have classified the injury into five types: type 1, unilateral lumbosacral facet-dislocation with or without facet fracture; type 2, bilateral lumbosacral facet-dislocation with or without facet fracture; type 3, unilateral lumbosacral facet-dislocation and contralateral lumbosacral facet fracture; type 4, dislocation of the body of L5 with bilateral fracture of the pars interarticularis; and type 5, dislocation of the body of L5 with fracture of the body and/or pedicle, with or without injury of the lamina and/or facet. Conservative treatment of fracture-dislocation of L5 is generally not effective because the lesion is fundamentally unstable. Planning of the operation should be made on the basis of the various types of injury.

Adolescent↗
PubMed1998

Pheochromocytoma arising from an accessory adrenal gland in a patient with multiple endocrine neoplasia type 2A: transient development of clinical manifestations after hemorrhagic necrosis.

A case of pheochromocytoma arising from an accessory adrenal gland in a patient with multiple endocrine neoplasia type 2A (MEN 2A) is reported. This tumor resulted in autonecrosis which caused transient expression of clinical symptoms. Scintigraphy of the abdomen identified the existence of an additional accessory adrenal gland because of which the patient did not require a supplement of hydrocortisone after bilateral total adrenalectomy. Pheochromocytoma arising from an accessory adrenal gland is rarely reported, and spontaneous remission of clinical symptoms due to necrosis of the pheochromocytoma without a clinical emergency is also unusual. Accessory adrenal glands can be the cellular basis for pheochromocytoma, and the importance of continual follow up for pheochromocytoma in subjects with MEN 2A should be emphasized.

Adrenal Gland Neoplasms↗
PubMed1998

Glyceraldehyde-3-phosphate dehydrogenase mRNA expression in hepatocellular carcinoma.

Glyceraldehyde-3-phosphate dehydrogenase (G3PDH) is often used as a control gene for mRNA expression, however it has been proposed to be overexpressed in all hepatocellular carcinomas (HCC). Equal amounts of tumor and paired normal (T/N) RNA, based on OD260/280 nm, were compared using ethidium bromide staining, poly-T probing, gene-specific dot blot and Northern blots using control probes G3PDH, actin and histone H4. Using mRNA blots 13/20 surgical HCC pairs did not overexpress G3PDH. Those 7/20 intact samples which did appear to overexpress G3PDH on Northern blot could not be detected by poly-T probing of dot blots. The apparent overexpression was not specific for the control gene G3PDH nor for the malignancy HCC. It may represent partial mRNA degradation, or the presence of as yet unknown substances which interfere with absorption at 260/280 nm. We advise caution in selecting human T/N pairs for differential gene expression studies. For HCC, no clinicopathological variables, including cirrhosis, predicted whether a T/N sample pair was likely to be balanced or not.

Carcinoma, Hepatocellular↗
PubMed1998

Expression of insulin-like growth factor 2 mRNA in human gastric cancer.

Insulin-like growth factor 2 (IGF2) stimulates cell proliferation and development in normal human growth. In several human cancers, the IGF2 gene is overexpressed and is thus considered to be a growth factor for tumors mediated through both the paracrine and autocrine pathways. However, the significance of IGF2 mRNA expression in gastric cancer has yet to be clarified. We semi-quantitatively measured the expression of IGF2 mRNA in 57 Japanese cases of gastric cancer by means of the reverse transcription polymerase chain reaction and also analyzed the relation between the IGF2 expression status and other clinicopathologic factors. We also performed immunohistochemical staining for IGF2. In 41 of 57 cases (72%), the expression of IGF2 mRNA was greater in tumor tissue (T) than in normal tissue (N). The average tumor/normal (T/N) expression ratio of IGF2 mRNA corrected for that of control gene mRNA was 1.42, while ranging from 0.36 to 3.65. The T/N ratio of infiltrative-type cancers was greater than that of expanding-type cancers (p<0.05). The cases with lymphatic permeation showed a greater T/N ratio than those without lymphatic permeation in expanding-type cancers (p<0. 05). Immunohistochemical staining revealed IGF2 to be detected in cancer cells themselves, especially at the margin of the cancer tissue. The IGF2 gene may thus play an important role in lymph vessel permeation especially in expanding-type gastric cancers.

Gene Expression↗
PubMed1998

[Two patients with obstructive jaundice due to intra-abdominal lymph-node metastases of gastric cancer responding to combination chemotherapy with 5-FU and CDDP].

Combination chemotherapy with 5-FU and CDDP was given to two patients with obstructive jaundice due to intra-abdominal lymph-node metastases of advanced and recurrent gastric cancer. One patient was a primary case associated with lymph-node metastases of portal fissure and periaorta, and the other was a recurrent case associated with lymph-node metastases of hepatoduodenal ligament and periaorta. The regimen consisted of 5-FU 1,000 mg/ m2 (day 1-5, continuous infusion) and CDDP 100 mg/m2 (day 3, 1 hr drip infusion). The interval was from the 6th to 21st day. The response to chemotherapy showed shrinking of intra-abdominal lymph-nodes and reopening of the biliary tract. The patients could be discharged from the hospital without PTBD tube and enjoyed a better quality of life (QOL). This therapy is thought to be effective against obstructive jaundice due to intra-abdominal lymph-node metastases of advanced and recurrent gastric cancer.

Abdomen↗
PubMed1997

Reduction in the ratio of beta-preprotachykinin to preproenkephalin messenger RNA expression in postmortem human putamen during aging and in patients with status lacunaris. Implications for the susceptibility to parkinsonism.

Gamma-aminobutyric acid (GABA)/substance P (SP) neurons and GABA/enkephalin (Enk) neurons in the striatum exert opposing influence on the regulation of movement. The loss of GABA/SP neurons results in hypokinetic disorders (parkinsonism), whereas the loss of GABA/Enk neurons results in hyperkinetic disorders (e.g. chorea). The present study determined age-related changes in the beta-preprotachykinin (the precursor of SP) and preproenkaphalin (the precursor of Enk) messenger RNA (mRNA) ratio in the postmortem human putamen using the reverse transcription-polymerase chain reaction (RT-PCR). The ratio of beta-preprotachykinin to preproenkephalin mRNA expression decreased with age. The reduction in the beta-preprotachykinin/preproenkephalin mRNA ratio was more marked in cases with multiple small infarcts (status lacunaris) in the putamen. These findings may in part explain the susceptibility of the elderly, particularly of those with ischemic changes in the striatum to hypokinetic disorders.

Adult↗
PubMed1997

Hepatocellular carcinoma with sarcomatous change arising in primary biliary cirrhosis.

We report an autopsy case of hepatocellular carcinoma (HCC) with sarcomatous change arising in the context of primary biliary cirrhosis (PBC) in a 79-year-old man. Primary biliary cirrhosis was diagnosed (stage I according to Scheuer's classification) by findings on blood biochemical analysis, laparoscopy, and liver biopsy at age 69 years. Five years later, (at age 74 years), a mass lesion was detected in the S6 region of the liver by abdominal ultrasonography, and target biopsy revealed well differentiated HCC. Blood biochemistry, ultrasonography, and computed tomography findings showed that the PBC had progressed to stage IV (cirrhotic stage). Percutaneous ethanol injection therapy (PEIT) was administered to the HCC several times over a 5-year period; however, the patient died of liver failure in February, 1994 (at age 79 years). Viral markers for hepatitis B and C were negative during the course, and hepatitis C virus RNA was not detected by polymerase chain reaction. Autopsy findings showed liver cirrhosis and diffuse involvement of spindle-shaped sarcomatoid cells in the liver, particularly in the S6 region, associated with several nodules of trabecular HCC cells. A zone of transition between the sarcomatoid cells and the trabecular hepatocellular carcinoma cells was observed. The sarcomatoid cells were diffusely disseminated in the peritoneal cavity and had metastasized to multiple organs. Immunohistochemically, the cells were positive for fibrinogen, as were the coexisting trabecular hepatocellular carcinoma cells. The HCC had been treated several times with PEIT. Of interest, PEIT may be an important factor in this type of tumor progression.

Aged↗
PubMed1997

Flexibility in the scoliotic spine: three-dimensional analysis.

The purpose of this study was to measure the three-dimensional geometry of scoliosis by using biplane radiographic photogrammetry and to evaluate the flexibility of the deformed spine. Thirty-one patients with idiopathic scoliosis underwent analysis. There was a significant correlation between the degree of the scoliotic angle in the frontal plane, kyphotic angle in the sagittal plane, and the rotational angle of the apical vertebra. Hypokyphosis was associated with a scoliotic angle > 40 degrees in the frontal plane. Similarly, hypokyphosis was related to increased rotation of the apical vertebra (p < 0.01). Although the scoliotic angle was decreased by traction in all cases, axial rotation was less corrected in those patients with scoliotic angle > 40 degrees. This suggests that the rotational stiffness at the apex is related to the degree of the rotational angle of the apical vertebra and to the degree of the frontal curve.

Adolescent↗
PubMed1997

[Effects of CTG repeat expansion on quantitative muscle histopathology in myotonic dystrophy].

The CTG trinucleotide repeat (CTG repeat) length in leukocytes and muscles shows significant correlations with muscle weakness, an increase in type 1 fiber proportion, and reductions in type 2A and 2B fiber proportions in patients with myotonic dystrophy (DM). The correlations are generally greater for CTG repeat length in muscles than in leukocytes. However, relatively small absolute values of correlation coefficients (r2 = 0.13-0.43) suggest that the CTG repeat length is not a role variable that may explain clinical and histopathological changes in DM patients.

Adult↗
PubMed1997

Effects of intravenous lipoprostaglandin E1 on neurogenic intermittent claudication.

Circulation disturbances in the cauda equina and nerve roots have been implicated in the genesis of neurogenic intermittent claudication (NIC) in patients with lumbar spinal stenosis (LSS). We report the clinical results of lipoprostaglandin E1 (lipo-PGE1) treatments in patients with NIC. Lipo-PGE1 was administered intravenously for 10 consecutive days to 40 patients, 31 of whom showed a response to the treatment. Of the clinical symptoms examined, walking ability and leg numbness were significantly improved with an average effective period of 2.5 months. However, patients with radicular pain and severely affected patients did not respond well. Nerve root circulation in eight patients who subsequently underwent surgery was measured with a laser Doppler flowmeter. We observed increased blood flow in seven of these eight patients, after the intraoperative administration of lipo-PGE1. Lipo-PGE1 produced symptomatic improvement for a limited period in the treatment of NIC associated with LSS. The drug appeared to exert its effects through an increase in the circulation of blood in the nerve roots and the cauda equina.

Adult↗