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Biomedical subjects

H Iwamoto

Publications and source records attributed to H Iwamoto.

At least 199 records · Page 11Linked to original sources
PubMed1991

Serum factor from patients with cirrhosis and hepatocellular carcinoma enhances production of prostaglandin E2 by U937 cells.

The effect of serum from patients with cirrhosis and hepatocellular carcinoma on the release of prostaglandin E2 by the human histiocytic lymphoma cell line U937 was investigated to explain the mechanism underlying the immunoregulatory dysfunction of monocytes in cirrhosis and hepatocellular carcinoma. Prostaglandin E2 production by U937 cells cultured with serum from cirrhosis patients (5.9 +/- 2.7 ng/ml, p less than 0.01) and hepatocellular carcinoma patients (5.4 +/- 2.6 ng/ml, p less than 0.01) was significantly higher than that of control cultures (2.0 +/- 1.0 ng/ml). This activity was decreased after heating and after freezing and thawing. By size exclusion fast protein liquid chromatography, the probable factor was eluted in the fraction with a molecular weight of 150 kD. By anion exchange chromatography with a stepwise increase of the NaCl concentration, the peak activity augmenting prostaglandin E2 production by U937 cells was eluted in the 0.05 to 0.1 mol/L NaCl fraction. The high level of this factor (monocyte-regulating factor) in patient serum might be one cause of abnormal monocyte immunoregulatory function in cirrhosis and hepatocellular carcinoma.

Blood Physiological Phenomena↗
PubMed1991

Novel oligomannose-type sugar chains derived from glucose oxidase of Aspergillus niger.

The primary structure of the N-linked sugar chains of glucose oxidase from Aspergillus niger was investigated. These sugar chains were released from the polypeptide backbone by hydrazinolysis, and the reducing ends of the sugar chains were pyridylaminated. HPLC of the pyridylamino sugar chains with an amide-silica column showed at least seven sugar chain peaks. Chemical and exoglycosidase digestion and 400 lMHz H-NMR studies of the sugar chains of lower molecular weight showed that these were novel oligomannose-type sugar chains, (Man)5-7 (GlcNAc)2, with the structure: +/- Man alpha 1----3Man alpha 1----3(Man alpha 1----6)Man alpha 1----6(+/- Man alpha 1----3Man alpha 1---3)Man )Man beta 1----4GlcNAc beta 1----4GlcNAc.

Aspergillus niger↗
PubMed1991

Transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae.

Endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae has transglycosylation activity. Treatment of (Man)6(GlcNAc)2Asn with the enzyme in the presence of free N-acetylglucosamine gave a mixture of (Man)6GlcNAc and (Man)6GlcNAc beta 1----4GlcNAc mixture. N-Acetylglucosamine at the reducing end of the latter sugar chain was found by HPLC of the carbohydrate composition and of an exoglycosidase digest of the pyridylamino derivative of the reducing-end residue, and by 400 MHz 1H-NMR spectroscopy.

Acetylglucosamine↗
PubMed1991

[The problems of valproate therapy in severely handicapped children--valproate induced hyperammonemia and hypocarnitinemia].

Blood ammonia and serum free carnitine were measured in 49 severely handicapped epileptic patients treated with or without valproate. DL- or L-carnitine were administered to patients treated with valproate, and the effects of carnitine supplementation were evaluated. Furthermore we analyzed the relationship between serum free carnitine and nutrition. In patients treated with valproate, blood ammonia statistically increased, and serum free carnitine concentration statistically decreased. Free carnitine was low in tube-fed patients, as compared with that in oral-fed patients. Carnitine therapy was successful in improvement of hyperammonemia and hypocarnitinemia. It is concluded that hypocarnitinemia was caused not only by valproate therapy, but also by tube-feeding. Carnitine supplementation therapy is important to both hyperammonemia and hypocarnitinemia. But the long term effect of carnitine therapy remains to be studied further.

Adolescent↗
PubMed1991

[Mortality patterns of children with epilepsies in a children's medical center].

Two hundred and thirty-seven children have died who were seen in the Division of Neurology, Kanagawa Children's Medical Center from 1975 to 1989. They corresponded to about 11% of the total death in the hospital. A total of 128 cases of 237 deaths (54.0%) were suffering from epilepsies, most of whom were also complicated with other CNS disorders. The causes of death were pneumonia, respiratory failure and suffocation in 60%, whereas status epilepticus or convulsions only in 14%. About 40% of victims died at home or in an emergency room without effective resuscitation. Mortality was considered high in infantile spasms (16 out of 146, 11%) and in severe myoclonic epilepsy in infancy (4 out of 8, 50%). It was note worthy that 3 cases of severe myoclonic epilepsy in infancy died of status epilepticus and 2 died at home. Sixteen cases whose chief problems were partial epilepsies and severe myoclonic epilepsy in infancy, died of status epilepticus in 10 cases, convulsions after tonsillectomy, etc. Causes of death of these 16 cases were related to convulsions except in two cases whose causes were pneumonia in one and unknown in the other. About a half of them (7 cases) died at home. Adequate managements appeared necessary to prevent accidental deaths of children with epilepsies.

Cause of Death↗
PubMed1991

[Four cases of Cockayne syndrome].

The evaluation of four patients with Cockayne syndrome (CS) by computed tomography (CT) and magnetic resonance imaging (MRI) is reported. All patients had characteristic clinical manifestations of CS. In a special respect, we found hyperopia in two patients and previous habitual abortions in two maternal histories. Extrapyramidal signs were seen in one patient. Three patients are type 1 CS (case 1, 3, 4) and one patient (case 2) is type 2 CS (congenital form). The cranial CT in two patients (case 1, 2) revealed prominent calcifications in basal ganglia, dentate nucleus and hemispheric white matter. While CT showed vagal calcifications in basal ganglia in other two patients (case 3, 4), T2-weighted MRI revealed obvious low intensity area in putamen and caudate nucleus, and high intensity area in the white matter. Sagittal section revealed atrophic changes of cerebellar vermis and brain stem. Thus it seems that MRI may be useful diagnostic adjunct in CS patients.

Brain↗
PubMed1991

Inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia.

A patient with inflammatory pseudotumor of the liver associated with acute myelomonocytic leukemia (M4) is reported. He had spiking fever, epigastralgia, and elevated levels of serum C-reactive protein (CRP) and alkaline phosphatase (ALP). Ultrasonography showed a hypoechoic mass in the liver, and ultrasonically guided fine needle aspiration biopsy of the mass revealed that it was composed of fibrous connective tissue infiltrated with plasma cells, eosinophils, and neutrophils. Accordingly, a diagnosis of inflammatory pseudotumor of the liver was made. Marked reduction in the size of the lesion and a decrease of the levels of the CRP and ALP occurred without specific treatment. We emphasize the importance of ultrasonically guided aspiration biopsy in diagnosis of inflammatory pseudotumor of the liver without the need for surgery.

Biopsy, Needle↗
PubMed1991

Effect of insulin, glucagon or dexamethasone on the production of insulin-like growth factor I in cultured rat hepatocytes.

We studied the effect of insulin, glucagon or dexamethasone on the production of insulin-like growth factor I (IGF-I) by cultured rat hepatocytes. Hepatocytes were isolated from normal adult rat livers and cultured in MEM, as nearly confluent monolayers. In the absence of such hormones, IGF-I and albumin accumulated in the culture medium almost linearly for periods up to 24 hours with the accumulation rates of 140 mU/mg cell protein per hour and 1.2 micrograms/mg cell protein per hour, respectively. Cycloheximide (5 micrograms/ml) almost completely inhibited the accumulation of IGF-I and albumin in the medium. Insulin at concentrations over 10(-10) M significantly inhibited the production of IGF-I in spite of the increased production of albumin. Conversely, glucagon stimulated the production of IGF-I at concentrations over 10(-8) M, but inhibited the production of albumin at concentrations over 10(-10) M. Dexamethasone stimulated the production of IGF-I at concentrations over 10(-7) M, but had no significant effects on the production of albumin. Thus, IGF-I production of hepatocytes is regulated by several hormones with different manner from albumin production.

Animals↗
PubMed1990

X-ray diffraction and electron microscopy from Lethocerus flight muscle partially relaxed by adenylylimidodiphosphate and ethylene glycol.

The low-angle X-ray diffraction pattern from Lethocerus flight muscle fibres was recorded in rigor or under two conditions that modify crossbridge structure and behaviour, aqueous adenylylimidodiphosphate (AMPPNP) and AMPPNP + calcium in an ethylene glycol-water mixture. The effects on the 38.7 nm layer-line peaks (hk.6) of the diffraction patterns were studied in detail. In aqueous AMPPNP at room temperature, a condition in which rigor tension drops to half without loss of stiffness, the peaks remained nearly as intense as in rigor except for the 10.6, which dropped to half. In 20% (v/v) ethylene glycol-AMPPNP + 100 microM-Ca2+ at 23 degrees C (gly + pnp + Ca), a condition which removed muscle tension but left stiffness close to the rigor value, the 10.6 and 11.6 peaks greatly decreased but the 31.6 remained relatively high. The 14.5 nm meridional peak (00.16) became stronger on addition of AMPPNP and again on adding glycol + calcium. Considered in terms of constructively interfering filaments and crossbridges, the X-ray data indicated a transfer of diffracting crossbridge mass towards the thick filament as relaxation proceeds. We compared the X-ray diffraction patterns and crossbridge structure seen with electron microscopy (EM) under the same chemical conditions. EM and X-ray observations were mutually quite consistent overall. However, X-ray data indicated that more crossbridge mass was stereospecifically related to actin before fixation in the partially relaxed state (gly + pnp + Ca) than was suggested by the disordered crossbridge profiles seen by EM. We conclude that myosin heads at the start of the power stroke may both be closely related to their thick filament origins and form actin-determined attachments to the thin filament.

Adenosine Triphosphate↗
PubMed1990

Expression of HTLV-I envelope protein fused to hydrophobic amino-terminal peptide of baculovirus polyhedrin in insect cells and its application for serological assays.

The envelope of human T-cell leukemia virus type I (HTLV-I) consists of two glycoproteins gp46 and p20E. Recombinant envelope proteins were produced by using an expression vector derived from insect baculovirus, Bombyx mori nuclear polyhedrosis virus. Polyhedrin fusion proteins C182, N147, and N287 contained whole region p20E, C-terminal half of gp46, and almost whole region gp46, respectively. N147 and N287 were suggested to be processed forms resulting from internal cleavage by cellular enzymes. In cultured cells and the insect larvae, C182 and N147 were produced abundantly enough to be purified to homogeneity; however, N287 was produced poorly and not purified. The purified proteins were recognized by HTLV-I-infected human sera and shown to be highly specific antigens for blood screening systems.

Amino Acid Sequence↗
PubMed1990

Causes of death in the elderly and their changing pattern in Hisayama, a Japanese community. Results from a long-term and autopsy-based study.

The causes of death for the elderly were prospectively studied in Hisayama, Japan, a rural community. We compared 1,621 subjects, aged 40 years or over, recruited in 1961, and 2,053 subjects recruited in 1974. Each cohort was studied in a follow-up that lasted 10 years; they had autopsy rates of 82.1% and 86.1% during each 10-year period, respectively. The most common causes of death for those aged 70 years or over were cerebrovascular disease, malignant neoplasms, and pneumonia. Deaths due to cerebrovascular disease tended to decrease in the recent cohort, but the proportion of decline was more prominent in cases aged 40 to 69 years. There was a sex difference in the changing pattern of mortality from heart diseases including ischemic heart disease. Deaths by both heart diseases and ischemic heart disease increased in the more recent cohort of aged women, whereas they decreased in the aged men. Pneumonia was an important cause of death for the elderly in both cohorts. Deaths due to "senility" were rare, being only 1% of the deceased aged 70 or over. With prolonged lifespan, especially for women, the impact of atherosclerosis and its related disorders on the recent Japanese aged population appears to have increased.

Adult↗
PubMed1990

Force-velocity relation of frog skeletal muscle fibres shortening under continuously changing load.

1. The force-velocity (P-V) relation of single frog skeletal muscle fibres was examined in non-steady-state conditions in which the load on the fibre changed continuously with time. Two such types of condition were used; in one type, the load was increased from zero to the maximum isometric force (P0) (auxotonic condition), while in the other type the load was decreased form P0 to zero at constant rates (ramp decrease in load). 2. The P-V curves obtained in the auxotonic condition were convex upwards and always below the hyperbolic P-V curve obtained in the isotonic condition. Different curves were obtained depending on the compliance of auxotonic load. The shortening velocity for a given amount of load increased with increasing compliance. 3. Qualitatively similar P-V relations were obtained irrespective of whether the fibre was made to shorten auxotonically at the onset of stimulation or after the development of P0. 4. If the force at any time after the onset of auxotonic shortening was normalized relative to the isometric force at the same time after the onset of isometric force development, the normalized force versus velocity curves were found to fit well to the hyperbolic P-V curve in the isotonic condition except for the low-force region. 5. The P-V curves obtained during the ramp decrease in load were hyperbolic in shape except for the humps at the high-force region and always above the P-V curve in the isotonic condition. Different curves were obtained depending on the rate of load decrease. The maximum shortening velocity increased with increasing rate of load decrease. 6. The above features of the P-V relations could well be simulated by a simplified Huxley contraction model, indicating that the kinetic properties of the cross-bridges are the same in both steady- and non-steady-state conditions.

Animals↗
PubMed1990

Diabetic hypouricemia as an indicator of clinical nephropathy.

We studied the possible association of the low serum uric acid level with incipient diabetic nephropathy in non-insulin-dependent diabetes mellitus (NIDDM). Of 201 NIDDM patients without a diminished glomerular filtration rate, 66 patients (32.8%) showed moderate hypouricemia of less than the mean-1 SD of 201 nondiabetic controls. Thirteen (6.5%) showed marked hypouricemia of less than the mean-2 SD. Hypouricemic patients showed normal daily urinary urate excretion with a markedly elevated urate clearance/creatinine clearance ratio. Most were under poor glycemic control, and presented either negative or intermittent clinical proteinuria. However, neither poor glycemic control, nor the presence of proteinuria or retinopathy alone significantly affected the serum uric acid level of the whole diabetic population. The glomerular filtration rate was determined in comparable groups of diabetic patients with hypouricemia and nonhypouricemic diabetic controls. The hypouricemic group showed a significantly higher endogenous creatinine clearance and lower serum beta-2-microglobulin levels than the nonhypouricemic group. These findings suggest that the hypouricemic group had a higher glomerular filtration rate. Long-term observation of up to 12 years of the above patients revealed that, in most patients, persistent hypouricemia was observed prior to the initial appearance of intermittent proteinuria. We hypothesize that glomerular hyperfiltration also occurs in NIDDM and that it lowers the serum uric acid by increasing the renal clearance of urate. Hypouricemia may also predict the future progression of incipient nephropathy in NIDDM.

Blood Glucose↗
PubMed1990

Renal tubular hypouricemia: evidence for defect of both secretion and reabsorption.

Two patients had hypouricemia due to increased uric acid clearance. They showed no decrease of urate clearance to creatinine clearance ratio (Cua/Ccr) following pyrazinamide administration, and no increase of Cua/Ccr after probenecid. One patient showed a limited decline in Cua/Ccr after intravenous furosemide. In the other patient, neither acetylsalicylate nor furosemide produced any noticeable change in Cua/Ccr. Both showed a normal diuretic response after intravenous furosemide. The results indicate that they had massive defects in urate transport along the nephron, probably including both secretion and reabsorption.

Aged↗
PubMed1990

Liver abscess complicating intratumoral ethanol injection therapy for HCC.

We report a patient who developed multiple liver abscesses and sepsis caused by lactobacilli after the percutaneous intratumoral injection of ethanol for hepatocellular carcinoma. We diagnosed the liver abscess at an early stage because of a the finding of gas on ultrasound and computed tomography. Blood cultures grew Gram-positive rods, which were of the Lactobacillus species. The patient responded to the administration of antibiotics, and his hepatic tumors have not recurred in the 7 months since treatment. This is the first report of liver abscess following percutaneous ethanol injection therapy.

Aged↗
PubMed1989

High invasiveness associated with augmentation of motility in a fos-transferred highly metastatic rat 3Y1 cell line.

We previously reported that v-fos transfer to a src-transformed rat 3Y1 cell line enhanced lung metastasis. To clarify the mechanism of this enhancement, we compared various biological factors related to metastatic potential between a fos-transferred highly metastatic cell line (fos-SR-3Y1-202) and the control cell line transferred with genetic marker (pSV2-neo) plus pBR322, neo-SR-3Y1-200. Lung arrest, the effect of lung extract on cell growth, or sensitivity to natural killer cells could not explain the higher metastasis of fos-SR-3Y1-202, compared to findings with neo-SR-3Y1-200. The invasiveness, assessed by penetration through a Matrigel-coated filter was about 5 times higher in fos-SR-3Y1-202 than in neo-SR-3Y1-200; high invasiveness in vitro was also observed in a fos-transferred mixed-population cell line (fos-SR-3Y1-200) and fos-transferred highly metastatic clones. Histopathological evidence of an in vivo tumor also showed the high invasiveness of fos-SR-3Y1-202 cells. To elucidate the causes of the increased invasiveness of fos-SR-3Y1-202, attachment of the cells to Matrigel and its components, such as laminin and type IV collagen, type IV collagenase activity, and motility were examined. Attachment of the cells to the substrate coated on Petri dishes or the activity of type IV collagenase did not differ significantly. On the other hand, cell motility, determined by a new method to directly quantitate alteration of cell shape continuously, using video image analysis and computer techniques, was higher in fos-SR-3Y1-202 than in neo-SR-3Y1-200. Thus, the fos-transferred cell line, fos-SR-3Y1-202 has a high invasiveness, in association with augmentation of motility, hence the enhancement of metastatic potential.

Animals↗
PubMed1989

Simultaneous recordings of force and sliding movement between a myosin-coated glass microneedle and actin cables in vitro.

To elucidate the molecular mechanism of muscle contraction resulting from the ATP-dependent actin-myosin interaction, we constructed an assay system with which both the force and the movement produced by the actin-myosin interaction in vitro can be simultaneously recorded and analyzed. The assay system consisted of the giant internodal cells of an alga, Nitellopsis obtusa, which contain well-organized arrays of actin filaments (actin cables) running along the cell long axis, and a glass microneedle (tip diameter, approximately 7 microns; elastic coefficient, approximately 40 pN/microns), which was coated with skeletal muscle myosin at the tip and extended from a micromanipulator at right angles with the actin cables. When the myosin-coated tip of the microneedle was brought into contact with the exposed surface of the actin cables, it exhibited ATP-dependent movement along the actin cables over a distance of 20-150 microns in 20-200 s (20-23 degrees C) and eventually stopped due to a balance between forces generated by the actin-myosin interaction (800-6000 pN) and by the bent microneedle. Since the load on the force-generating myosin molecules increased with the bending displacement of the microneedle (auxotonic condition), the relation between the load and the sliding velocity of the myosin heads past the actin cables was determined from the time course of the microneedle movement recorded with a video system. The shape of the force-velocity curve thus obtained was convex upwards, similar to that of the force-velocity curve of intact frog muscle fibers obtained under the auxotonic condition.

Actins↗