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Biomedical subjects

M Wada

Publications and source records attributed to M Wada.

At least 397 records · Page 22Linked to original sources
PubMed1995

Synthesis of fluoroacetate from fluoride, glycerol, and beta-hydroxypyruvate by Streptomyces cattleya.

Streptomyces cattleya produces fluoroacetate and 4-fluorothreonine from inorganic fluoride added to the culture broth. We have shown by 19F nuclear magnetic resonance (NMR) spectrometry that fluoroacetate is accumulated first in the culture broth and that accumulation of 4-fluorothreonine is next. To show precursors of the carbon skeleton of fluoroacetate, we carried out tracer experiments with various 14C- and 13C-labeled compounds. Radioactivity of [U-14C]glucose, [U-14C]glycerol, [U-14C]serine, and [U-14C]beta-hydroxypyruvate was incorporated into fluoroacetate to an extent of 0.2 to 0.4%, whereas [3-14C]pyruvate, [2,3-14C]succinate, and [U-14C]aspartate were less efficiently incorporated (0.04 to 0.08%). The addition of [2-13C]glycerol to the mycelium suspension of Streptomyces cattleya caused exclusive enrichment of the carboxyl carbon of fluoroacetate with 13C; about 40% of carboxyl carbon of fluoroacetate was labeled with 13C. We studied the radioactivity incorporation of [3-14C]-, [U-14C]-, and [1-14C]beta-hydroxypyruvates to show that C-2 and C-3 of beta-hydroxypyruvate are exclusively converted to the carbon skeleton of fluoroacetate. These results suggest that the carbon skeleton of fluoroacetate derives from C-1 and C-2 of glycerol through beta-hydroxypyruvate, whose hydroxyl group is eventually replaced by fluoride.

Carbon Isotopes↗
PubMed1995

Hepatic denervation does not significantly change the response of the liver to glucagon in conscious dogs.

In view of the increasing frequency of liver transplantation, and the importance of glucagon in the minute-to-minute regulation of glucose production, we assessed the effect of hepatic denervation on the liver's response to a physiological rise in glucagon in 18-h fasted dogs. Before study (2 wk), the dogs underwent liver denervation (DN; n = 6) or sham operation (SH; n = 5). Endogenous insulin and glucagon secretion were inhibited using somatostatin, and the two hormones were replaced intraportally in basal amounts. After the control period the glucagon infusion rate was tripled for 3 h. Glucagon increased from 41 +/- 8 to 128 +/- 8 and 54 +/- 4 to 129 +/- 9 pg/ml in SH and DN, respectively (P < 0.05), causing tracer-determined glucose production to increase from 2.5 +/- 0.1 to 4.9 +/- 0.5 and 2.3 +/- 0.1 to 5.8 +/- 0.8 mg.kg-1.min-1 by 15 min, respectively (P < 0.05). Glucose clearance fell slightly during glucagon infusion in DN, causing a somewhat greater increase in the plasma glucose level (to 175 +/- 15 vs. 207 +/- 20 mg/dl). The changes in gluconeogenic efficiency increased 65-90% in both groups (P < 0.05). In conclusion, denervation of the liver failed to significantly alter the metabolic response of that organ to a half-maximally effective increment in the plasma glucagon level.

Alanine↗
PubMed1995

Effect of maternal diabetes on longevity in offspring of spontaneously hypertensive rats.

We studied the effect of maternal diabetes induced by neonatal streptozotocin treatment on the longevity of the male offspring in spontaneously hypertensive rats (SHR). Maternal diabetes significantly decreased the survival in the offspring as compared with the control (p < 0.01). Mean age at death was 14.9 +/- 0.6 months in the offspring from the diabetic dams and 17.9 +/- 1.1 months in that from the control. The life span was significantly correlated with the birth weight (rs = 0.55, p = 0.009). These findings suggest that a diabetic pregnancy may accelerate an age-related degenerative process of the offspring in SHR.

Animals↗
PubMed1995

Disposition of diadenosine 5',5"'-P1,P4-tetraphosphate (Ap4A) in rats.

The disposition of diadenosine 5'5"'-P1,P4-tetraphosphate (Ap4A), an endogenous dinucleotide, was investigated in rats. The degradation of Ap4A in rat plasma was very rapid and could be explained by a Michaelis-Menten equation: Km and Vmax values were 1.69 micrograms/ml and 4.32 micrograms/min/ml, respectively. Ap4A was degraded in rat plasma to ATP and AMP, but not to 2 ADP molecules, and these nucleotides were further degraded through adenosine. The degradations kinetics were examined. After intravenous bolus injection, Ap4A in plasma declined rapidly and the rate of elimination was dose-dependent: the biological half-life was about 3s at the dose of 1 mg/kg and was longer at 3 mg/kg. When Ap4A was administered by intravenous infusion (0.5 or 1.0 mg/kg/min), the plasma level rapidly reached a steady-state, which then rapidly declined after stopping the infusion.

Adenosine↗
PubMed1995

Heterotransplantation of human parathyroid glands into nude mice.

Heterotransplantation of human parathyroid tissues into nude mice was performed to investigate the characteristics of grafted tissues. Grafts prepared from hyperplasia, adenoma and normal glands which were resected at operation were implanted in the gluteus muscle of the recipient mice (female, KSNnu/nu strain). Graft function was evaluated by measuring human intact PTH concentrations in sera of the mice. Serum PTH concentrations 12 weeks after transplantation were correlated with the tissue volume in the mice which received one, two, four or eight pieces of 1 mm3 hyperplastic tissues. Changes in graft function were examined in the mice which received four grafts prepared from hyperplasia, adenoma or normal glands. Transplantation of parathyroid tissues resulted in an increase in PTH concentrations for 4 weeks, reaching a plateau thereafter. The level remained unchanged for 8 weeks. Serum PTH levels in the mice with grafts prepared from hyperplasia or adenoma were significantly higher than in those with grafts from normal glands, though without a significant difference between the mice with grafts from adenoma and from hyperplasia. Serum calcium levels were similar in all three groups. We also observed the response of grafted parathyroid tissue to a low calcium level in sera: there was higher PTH secretion four weeks after the administration of the low calcium diet. The success of heterotransplantation was histologically proven by the presence of grafts which were not atrophic in the muscle 12 weeks after transplantation. Nucleoli were found more frequently, and nuclear pleomorphism was observed in the cells of heterografts.

Adenoma↗
PubMed1995

Occurrence of Graves' disease during retreatment with interferon-alpha 2a for chronic hepatitis C.

The present report describes a patient who developed Graves' disease 3 months after inception of retreatment with higher doses of interferon-alpha 2a for chronic hepatitis C, although the initial 6-month treatment caused no serious adverse reactions. Severe hyperthyroidism continued despite discontinuation of interferon-alpha 2a, and the patient was subsequently treated with 131I. This case suggests careful evaluation of the safety of retreatment to prevent manifestation of such a complication in the retreatment of chronic hepatitis C with interferon.

Adult↗
PubMed1995

[A study of osteopenia in elderly diabetic patients].

It is well known that IDDM cases can be complicated with osteopenia, but most of these results were reported using single photon absorptiometry. There have been few reports of diabetic osteopenia using dual energy X-ray absorptiometry (DXA), a method that is excellent for precise bone mineral measurement. Osteoarthritis and osteophytes of unknown origin in the lumbar vertebrae are often observed in elderly NIDDM patients. In this study, we examined the clinical characteristics of decreased bone mineral density (BMD) and whether anteroposterior (AP) scanning of the lumbar vertebrae (L2-L4) provides sufficient informations concerning osteopenia in elderly diabetic patients. The study was performed using DXA, which can quantify regional BMD throughout the body. The BMD in the total body and that in the lumbar vertebrae were measured by DXA (Lunar Co.) in 68 diabetics over age 60, 33 males and 35 females, mean age 68 +/- 8 yr, (mean +/- SD) and in 94 middle-aged diabetics (40 to 59), 56 males and 38 females, mean age 51 +/- 4 yr. The percentage of decrease in regional BMD in diabetic patients differed significantly by age and gender. The BMD in the head and spine especially decreased after menopause in women. However, the BMD of the leg and spine did not decrease with age in men. When the BMD of the lumbar vertebrae was plotted against the Y axis and the BMD in the total body against the X axis, the slope of the curve showed a greater increase in elderly diabetics than that in middle aged diabetics (1.8 vs 1.5) suggesting the BMD in the lumbar vertebrae has been overestimated.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1995

Water-soluble viscous substance of Jew's mellow leaves lowers serum and liver cholesterol concentrations and increases fecal steroid excretion in rats fed a high cholesterol diet.

The effect of Jew's mellow leaf powder and its water soluble viscous substance on cholesterol metabolism in rats fed a high cholesterol diet was examined. When compared to the controls, total serum and liver cholesterol concentrations were significantly decreased or tended to decrease in the groups given dry powder of fresh Jew's mellow leaves, dry powder purchased from the market or residual powder after extracting with ethanol, whereas no difference was observed in those given residual powder after extracting with water. There were significant increases or increasing tendencies in the fecal excretion of bile acids, total neutral sterols and cholesterol in those fed the experimental diets when compared to the control group. Rats fed a diet containing a water-soluble viscous substance (1.7%, about 1% as dietary fiber) obtained from the dry powder of Jew's mellow leaves showed significant decreases in serum and liver cholesterol concentrations and increases in fecal excretions of bile acids and neutral sterols. Based on the above, the component of dry powder of Jew's mellow leaves that is effective in decreasing serum and liver cholesterol concentrations was found to be a soluble dietary fiber, and the mechanism was assumed to be largely due to the increased excretion of bile acids and neutral sterols.

Animals↗
PubMed1995

[Spontaneous dissecting aneurysm of the superficial temporal artery: a case report].

Aneurysms of the superficial temporal artery are rare, and usually traumatic in origin. We present a very rare case of spontaneous dissecting aneurysm of the superficial temporal artery in a 46-year-old man. The patient had pulsatile headache in the right temporal region, and a pulsatile mass in the same region. His headache gradually worsened for which he came to our hospital. On examination, there was a pulsatile mass of 1.5cm x 3cm at the right temporal region, which disappeared when the main trunk of superficial temporal artery was compressed. There was no neurological abnormality. On computed tomographic examination, there was a spotty high density area in the right extracranial region corresponding to the right superficial temporal artery, which was strongly enhanced after contrast medium administration. On MRI examination, the same area showed high intensity, but at inner space there was signal loss on T1WI, T2WI and PDWI. Angiography showed an aneurysmal dilatation at the right superficial temporal artery and both the true lumen and the false lumen were recognized. Excision of the aneurysm under local anesthesia was performed. His complaints disappeared completely post-operatively, and the skin color of that region retained its normal texture. Histopathological examination of the specimen showed hypertrophic intima with fibroblasts, and absence of internal elastic lamina. There was hematoma outside of the intima, but no deposits of hemosiderin. On account of the above findings, the lesion was diagnosed as a spontaneous dissecting aneurysm of the superficial temporal artery.

Aortic Dissection↗
PubMed1995

[Ruptured distal anterior cerebral artery aneurysm and diagnostic dyspraxia: a case report].

A case of ruptured distal anterior cerebral artery aneurysm presenting with diagnostic dyspraxia is presented. A 54-year-old female was referred to our hospital with the complaint of sudden onset of headache followed by disturbance of consciousness. CT and MRI revealed subarachnoid hemorrhage with hematomas in the interhemispheric fissure and the supracallosal area, and CAG revealed a left-sided callosomarginal artery aneurysm. During and after hospitalization, she showed diagnostic dyspraxia characterized by behavior of both her hands opposite to what might be expected e.g. when she tried to pick up a bowl, both her hands moved forward and held it at once; she wiped her head and face with toilet paper after urination. At times her hands behaved in opposite ways. For example, while folding cloths, her right hand tended to fold them while the left hand tended to unfold them; when she put on a sweater, as the right hand put it on, the left hand took it off; when she put her shirt into her trousers, one hand pushed it in while the other hand pulled it out. This unusual behavior was considered to be caused by the impairment of the corpus callosum due to compression by the hematoma. It disappeared gradually over a period of one year. Involuntary motor behavior of the left hand while the right hand is in voluntary action is known as diagnostic dyspraxia. Although this symptom has rarely been reported so far in cases of ruptured distal anterior cerebral artery, it may become noticed more frequently through careful observation.

Aneurysm, Ruptured↗
PubMed1995

Utilization of dietary protein in the vitamin B12-deficient rats.

Utilization of dietary protein in vitamin B12 (B12)-deficient rats was evaluated by determinating the content of plasma protein, urinary excretion of nitrogen compounds, and nitrogen-balance after the rats were fed on a B12-deficient soy bean protein diet by pair-feeding for 100 days. The severe B12-deficiency was confirmed in rats by a remarkable increase in urinary methylmalonic acid excretion and a remarkable decrease in the hepatic B12 level. Growth of B12-deficient rats was significantly retarded as compared both with ad libitum-feeding control rats and pair-feeding control rats. The growth retardation due to B12-deficiency was alleviated by the administration of 1 microgram/day of CN-B12 for 30 days. Plasma total protein and albumin levels in rats fed on a B12-deficient diet decreased, compared with those in pair-feeding control, and increase in urea-nitrogen was observed. The excretion of urinary nitrogen compounds, such as urea-nitrogen, allantoin, and creatinine, was significantly depressed by B12-deficiency compared with those in pair-feeding control. The administration of CN-B12 to B12-deficient rats for 30 days resulted in the recovery of the changes in plasma proteins and urinary excretion of nitrogen compounds. The above results suggested that the extreme B12-deficiency depressed the utilization of dietary protein in rats. Moreover, the decrease in urinary urea-nitrogen excretion was supposed to be due to the adaptation by the depression of the dietary protein utilization.

Animal Nutritional Physiological Phenomena↗
PubMed1995

[Familial occurrence of intracerebral cavernous angioma: report of cases in brothers].

Familial occurrence of intracerebral cavernous angioma has been rarely reported. We report two histologically verified cases of cavernous angioma among brothers and review relevant cases in the literature. Case 1 is that of a 3-year-old boy who suffered front acute onset of headache, vomiting, and tonic-clonic type seizure. CT revealed a well-demarcated tumor with partial hemorrhage in the left frontal lobe which was strongly enhanced with contrast Medium. Complete excision was carried out and the patient had a satisfactory clinical course and was able to be followed up for 13 years after the Surgery. Case 2 is that of a 17-year-old boy who was the elder brother of case 1 and presented with gradually increasing episodes of a psychomotor seizure which started at the age of 16. CT and MRI revealed a well-demarcated tumor in the left subcortical temporal lobe and an asymptomatic small calcified lesion in the left subcortical parietal lobe. The temporal tumor was totally excised and histologically diagnosed as cavernous angioma. The seizures gradually decreased and eventually disappeared one year after the surgery. This report reviews 13 previously reported cases, and surgical indication for asymptomatic cases.

Adolescent↗
PubMed1994

Absence of WAF1 mutations in a variety of human malignancies.

A newly cloned gene named wild-type p53-activated fragment 1 (WAF1; also known as p21, Pic-1, Cip-1, or SDI1) is directly regulated by p53 and can itself suppress tumor cell growth in culture. Induction of expression of WAF1 may be an important means by which cells with DNA injury arrest their growth to repair DNA or undergo apoptosis. Based on the hypothesis that mutations of this gene may play a role in carcinogenesis, we have studied 351 DNAs from 14 kinds of malignancies, as well as 36 human transformed cell lines, for alterations of WAF1 gene by single-strand conformation polymorphism analysis of polymerase chain reaction amplification of the DNA coding region of the WAF1 gene. No abnormal band shifts of WAF1 were noted in any of the samples or cell lines, but three major variants in exons 2 and 3 of the gene were found that are consistent with the existence of two different DNA polymorphisms. Sequence analysis of the amplified products producing these three variants in each exon from normal DNAs confirmed the presence of the polymorphisms in the WAF1 gene. Of 290 selected tumor samples previously evaluated for p53 mutations by single-strand conformation polymorphism, 90% had no detectable p53 alterations. In summary, mutations within the coding portion of the WAF1 gene were undetectable in a large series of human tumors, many of which had a normal p53 gene. This suggests that WAF1 alterations are generally caused indirectly, through p53 mutations rather than through intragenic mutation of the WAF1 itself.

Base Sequence↗
PubMed1994

Cellular control of human multidrug resistance 1 (mdr-1) gene expression in absence and presence of gene amplification in human cancer cells.

The Kst-6 cell line is a human KB carcinoma cell line that has a stably integrated chloramphenicol acetyl-transferase (CAT) reporter gene under the control of the human mdr-1 promoter. Using Kst-6 cells as the parental cell line, five vincristine-resistant sublines, designated Kst-V5, -V25, -V50, -V75, and -V100, were isolated by exposure to increasing concentrations of drug. These sublines showed increased resistance to vincristine when compared with parental Kst-6 cells. Two sublines, V25-1 and V25-2, were further isolated from Kst-V25 after culture in the presence of vincristine, and V100-1 and V100-2 were also isolated from Kst-V100. Southern analysis demonstrated mdr-1 gene amplification in Kst-50, Kst-V75, Kst-V100, V100-1, and V100-2 cells, respectively, but not in Kst-V5, Kst-V25, V25-1, and V25-2 cells. In contrast, increased mdr-1 expression was documented by Northern analysis in Kst-V25, V25-1, and V25-2 cells and five cell lines with mdr-1 amplification. Southern blot analysis utilizing a CAT probe demonstrated a stable copy number in all vincristine-resistant sublines. However, Northern analysis documented increased CAT expression in Kst-V5, Kst-V25, V25-1, and V25-2 cells but reduced mRNA levels in the cell line with amplification of the endogenous mdr-1 gene. Expression of the CAT gene was increased along with the endogenous mdr-1 gene in the early steps of the selection but decreased with the onset of gene amplification. There appeared almost similar mRNA levels of two trans-acting factor genes, SP-1 and MDR-NF1/YB-1, which are supposed to be involved in mdr-1 gene promoter activation, among all cell lines used in this study. These findings suggest that transcription of both the CAT gene fused to the mdr-1 promoter and the endogenous mdr-1 gene is enhanced through activation by trans-acting factors in the early steps of drug selection. However, the quantity of trans-activating factor is limiting, and with the onset of gene amplification, less is available for activation of the CAT gene, resulting in decreased expression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1994

HPRT yeast artificial chromosome transfer into human cells by four methods and an involvement of homologous recombination.

The transfer of a yeast artificial chromosome (YAC) into mouse and human cell lines was effected by four methods, and the efficiency and integrity of the incorporated YAC DNA were compared. A 500 kb YAC containing the human hypoxanthine-guanine phosphoribosyl transferase (HPRT) gene was transferred more efficiently by polyethylene glycol-mediated fusion than by lipofection, electrofusion, or electroporation. Southern blot analysis demonstrated that PEG fusion lines yielded fragments of the size of the original YAC clone, whereas lipofection and electroporation did not. Two of 53 fusion lines showed 6-thioguanine resistance and confirmatory disruption of the HPRT gene in the YAC DNA, suggesting that the YAC DNA was integrated by homologous recombination with the endogenous HPRT gene region.

Animals↗
PubMed1994

Chimeric YACs were generated at unreduced rates in conditions that suppress coligation.

Chimerism is a major limitation of current YAC libraries. A method based on partially filled-in ends of restriction fragments was designed to avoid coligation as a possible source of chimeras. Model experiments using plasmid DNA as an insert showed that coligation was clearly avoided by this method. Pilot collections of YACs with an average insert size of 650kb were then constructed with and without the partial fill-in treatment. Starting from a mixture of a equal amounts of human and mouse DNA, none of 108 clones was positive by hybridization with both Alu and B2 probes, again suggesting that coligation was effectively blocked. However, 4 out of 10 clones still hybridized to 2 or more locations by FISH on chromosomes in human metaphase spreads, level similar to that in the clones made without the partial fill-in step. These results strongly suggest that chimeric clones generally arise by a mechanism independent of coligation, presumptively based on recombination.

Animals↗