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Biomedical subjects

N Murakami

Publications and source records attributed to N Murakami.

At least 505 records · Page 28Linked to original sources
PubMed1987

Relationship between translobular migration in perfused rat liver and hydrophobicity of dialkyl dithiolanylidenemalonates and related compounds.

The translobular migration of five dialkyl dithiolanylidenemalonates and five related compounds in perfused rat liver was determined and related with the hydrophobicity, log P. In the elution profile from the perfused rat liver, the peak position (elution volume) varied from 1.5 ml for dimethyl dithiolanylidenemalonate to 186 ml for the dibutyl analogue, dependent on the length of the alcoholic alkyl groups or the hydrophobicity of the compounds. An excellent correlation exists between--log (elution volume) and log P. The hydrophobic interaction with sinusoidal components seems to retard the compound migration from the periportal zone to the hepatic vein. Addition of rat blood (5% v/v) to the perfusion Tyrode solution accelerated the migration of hydrophobic compounds resulting in a gentler slope of the correlation plot. A similar correlation with log P was observed for translobular migrations of other xenobiotics such as naphthalene, nitroanisole, dichlorobenzenes and parathion in rat liver perfused with autologous blood.

Animals↗
PubMed1987

[The reactor accident at Chernobyl': identification of radionuclides in fallout in Niigata City].

The fallout caused by the accident of Chernobyl' nuclear reactor has been monitored in Niigata City (April 30-June 3, 1986). Twelve nuclides (131I, 132I, 129Te, 129mTe, 132Te, 134Cs, 136Cs, 137Cs, 103Ru, 99mTc, 140La, 140Ba) were identified in aerosol samples. The same nuclides plus 7Be were identified in rain-water. Gaseous and particle-bound 131I were separately trapped on a glass filter and a charcoal filter, respectively. Results indicate 50-60% of atmospheric 131I is gaseous and the rest is particle-bound. Chloroform extraction of rain-water revealed that 40-60% of 131I in the rain-water sample exists in the form of IO3- and 131IO3- (131IO4-)/131I- seemed to increase with the lapse of time after the accident.

Accidents↗
PubMed1987

[Correlation between disaturated phosphatidylcholine in amniotic fluid and fetal lung maturation].

The concentrations of disaturated phosphatidylcholine (DSPC), the major component of pulmonary surfactant, were quantified on 528 amniotic fluid samples, which did not show the contamination of blood or meconium and were uncomplicated by polyhydramnios or severe congenital anomalies incompatible with life. 396 samples of amniotic fluid (29 RDS cases) obtained 72 hours before delivery were used to evaluate the reliability of DSPC as a specific indicator in pedicting fetal lung maturation. DSPCs were determined according to the method described by Mason et al. and lecithin/sphingomyelin (L/S) ratios were measured by using two dimensional thin-layer chromatography. The critical points of DSPC and L/S ratio were defined as 1.0mg/dl, 2.0 respectively. The results are as follows. There was a gradual increase in DSPC levels of amniotic fluid with increasing maturity until 35 weeks of gestational age and a rapid rise from 36 weeks to term. About 70% of the amniotic fluids having a significantly higher DSPC level greater than or equal to 5.0mg/dl within 35 weeks of gestation were found to be obtained from pregnant women whose pregnancy was complicated by PROM, threatened premature labor or cervical incompetency and who eventually underwent preterm labor. Out of 58 samples, in which DSPC and the L/S ratio were measured simultaneously, two markers agreed in 47 cases in an immature or a mature value for predicting fetal lung maturation. RDS was correctly predicted in 27 of 60 cases (false negative, 55.0%) with DSPC levels less than 1.0mg/dl. When DSPC levels were 1.0mg/dl or more, there were only two of 336 (0.6%), false positives.(ABSTRACT TRUNCATED AT 250 WORDS)

Amniotic Fluid↗
PubMed1987

[Clinical efficacy of flomoxef in the field of pediatrics].

A new oxacephem antibiotic, flomoxef sodium (FMOX, 6315-S), was studied for its clinical efficacy in the field of pediatrics. The treated patients were infants and children ranging from 6 months to 14 years old suffering from bacterial pneumonia in 3 cases, acute tonsillitis in 2 cases, acute enterocolitis in 2 cases, and cellulitis and urinary tract infection in 1 case each, a total of 9 cases. FMOX was administered at (levels of) 57-150 mg/kg in daily dose with durations of treatment ranging from 5 to 18 days. Clinical efficacies of good or excellent results were obtained in all cases (excellent in 4, good in 5). As an adverse reaction, eosinophilia was observed in 1 patient. This elevation is, however, normalized with the cessation of the treatment.

Adolescent↗
PubMed1987

[A case of successful surgical treatment of rectal cancer complicated by acute myelomonocytic leukemia].

A 47-year-old man, who had been diagnosed as having acute myelomonocytic leukemia (AMMOL) and had been treated with combination chemotherapy, was admitted to our hospital because he had developed melena. He had been judged to be in complete remission and had shown no signs of recurrence for years, Daunorubicin, vincristine 6-Mercaptopurine and Cyclophosphamide had been administered for maintenance and intensification therapy. He was well until January 1986, when this melena began. A barium enema was given and he was diagnosed as having rectal cancer. Amputation of the rectum and a permanent abdominal colostomy was made safely, mainly because he had been in complete remission, and he recovered normally after the operation. In recent years, the survival of patients with malignancies has improved due to aggressive treatment even in cases of hematological neoplasms. However, the risk of secondary neoplasms in patients treated for cancer has increased. This case suggests that we have to be careful when prescribing treatment for cancer patients, since anti-tumor drugs may have cartinogenic effects.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Simultaneous determination of membrane potential and pH gradient by photodiode array spectroscopy.

Membrane potential (delta psi) and pH difference (delta pH) were simultaneously determined in liposomes using a photodiode array spectrophotometer. By the use of a cyanine dye (DiS-C3(5)) and 9-aminoacridine for delta psi and delta pH probes, respectively, both changes of delta psi and delta pH could be successfully determined by photodiode array spectrometry. Each dye did not disturb the fluorescence spectrum of the other probe when its concentration was lower than 5 microM. The K+-diffusion potential-driven, FCCP(protonophore)-mediated H+-influx process in the K+-loaded liposomes was analyzed by this method. Results indicate that the kinetic behavior of H+ influx changes at a FCCP concentration of approx. 30 nM. The rate of delta pH formation increased quantitatively with increasing concentrations of FCCP up to 30 nM, but was markedly enhanced at higher concentrations, although the maximal delta pH attained was about 3 pH units in any case when a K+-diffusion potential of -180 mV was applied.

Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone↗
PubMed1986

Regions necessary for pH-dependent assembly of gizzard myosin rod.

Aggregated and disaggregated forms of gizzard myosin rod and its fragments in various concentrations of NaCl (0-0.30 M) at various pH (7.4-8.6) were distinguished from each other by their permeability through a Sepharose 4B column. The rod existed in three forms, namely: large aggregates impermeable to the column, small aggregates eluted at the void volume of the column and a disaggregated monomer which penetrated the column. The relative proportions of the three forms varied depending on the salt concentration and pH. The monomeric rod was detected in NaCl solutions above 0.20 M and its relative proportion at 0.25 M NaCl was larger than those of the small and large aggregates. The small aggregates of the rod were predominant at below 0.05 M NaCl and, upon decrease in pH from 8.6 to 7.4, these small aggregates in NaCl solutions between 0.10 M and 0.15 M were replaced by the large aggregates. Light meromyosin, which corresponded to the C-terminal two-thirds of the rod, existed exclusively as large aggregates in NaCl solutions below 0.15 M; increase of NaCl concentration to above 0.20 M resulted in the formation of its monomer, instead of the large aggregates. In contrast to the rod, no small aggregated form of the light meromyosin was detected. Truncated light meromyosin which had lost a small segment from either the C-terminal or N-terminal of light meromyosin was eluted only as a monomer in any NaCl concentration at any pH. It may be deduced from the above results that a small segment in the light meromyosin is requisite for the assembly of both rod and light meromyosin in the NaCl solutions below 0.15 M and that the relative proportion of small and large aggregates of the rod is determined in a pH-dependent manner by the subfragment 2 segment, the N-terminal third of the rod.

Animals↗
PubMed1986

Activation of brain regions of rats during fever.

The central nervous structures involved in febrile responses were investigated in conscious rats by means of the 2-deoxy-D-[14C]glucose autoradiographic technique. An intravenous injection of endogenous pyrogen prepared from rabbit white blood cells induced a significant rise in the rectal temperature of rats accompanied by a decrease in the skin temperature. According to autoradiographs, significant increases in metabolic activity were observed in the lateral preoptic area, posterior part of dorsomedial thalamus, posterior hypothalamus and the red nucleus during an induced fever. Because of the close relationship between metabolic activity and brain function, these regions are considered to compose the neural components directly or indirectly related with the febrile responses.

Animals↗
PubMed1986

Changes in [14C]deoxyglucose incorporation into rat brain regions during heat-seeking behavior in the cold environment.

The central nervous structures involved in behavioral thermoregulatory responses during cold exposure were investigated in conscious rats by means of the 2-deoxy-D-[14C]glucose ([14C]-DG) autoradiographic technique. According to autoradiographs, many brain regions with significant increases or decreases in [14C]-DG incorporation were observed during thermoregulatory behavior. When animals were only exposed to cold, significant increases in [14C]-DG incorporation were observed in the caudate putamen, lateral preoptic area, medial forebrain bundle, ventromedial hypothalamus (VMH), posterior hypothalamus, ventroposteromedial thalamus (VPM), dorsomedial thalamus (MD), substantia nigra (SN) and red nucleus (RN). Lower activities were observed in the hippocampus and the medial habenula. However, when animals performed the behavioral thermoregulation (heat seeking behavior) significant increases were noted in the sulcal prefrontal cortex, sensory-motor cortex, and MD, while decreases were noted in the piriform cortex, VMH, VPM, medial habenula, SN and RN, compared with those in the group without the thermoregulatory behavior.

Animals↗
PubMed1986

Developmental aspects of epilepsy with special reference to age-dependent epileptic encephalopathy.

The specificity of childhood epilepsy was characterized by investigating the evolutional changes with age and prognoses of age-dependent epileptic encephalopathy from the developmental aspect through a long-term follow-up. Three types of age-dependent epileptic encephalopathy showed mutual evolutional changes at certain ages. This indicated an important role of the brain development in the clinicoelectroencephalographical manifestations of age-dependent epileptic encephalopathy. Furthermore, the evolutional changes demonstrated an association with organic brain damage and etiology in addition to the age factors. The evolutional changes occurred more frequently in the cases with overt organic brain pathology. The prognosis was poorer in cases which underwent an evolutional change.

Aging↗
PubMed1986

Cervical teratoma in a fetus and an adult. Two case reports and review of literature.

Two cases of cervical teratoma in a 30-weeks fetus and a 26-year-old female have been presented. In the former case a large mass entirely occupied the anterior neck but showed no invasive or metastatic lesions, and in the other case a mass containing multiple cysts was situated in the right lower pole of the thyroid gland. Histologically, both tumors were composed of the elements derived from three germ layers including various epithelial components, cartilage, muscle, and adipose tissue. In addition to these predominantly mature elements, there were some elements showing primitive immature structure in the former case. Positive immunohistochemical staining for thyroglobulin displayed only in the former case and was observed in the compressed thyroid follicles located in the fibrous capsule and several small foci of primitive glandular structure which was an element of the tumor.

Adult↗
PubMed1986

Suppression of non-shivering thermogenesis in the rat by heat-seeking behaviour during cold exposure.

Changes in rectal temperature (Tre) during cold exposure (0 +/- 1 degrees C) were observed in three groups of rats: heat-seeking, no-behaviour and semi-restrained groups. Significant increases in Tre were observed in the no-behaviour and the semi-restrained groups during cold exposure. In the heat-seeking behaviour group Tre remained constant during cold exposure. The increased Tre in the semi-restrained group during cold exposure was markedly attenuated by the systemic injection of beta-blocker (propranolol: 10 mg/kg, I.P.), indicating that this increase of Tre was caused by activation of non-shivering thermogenesis (n.s.t.). Furthermore, the rise in Tre in the semi-restrained group was preceded by a greater increase in the temperature of the interscapular brown adipose tissue. Using the autoradiographic [14C]deoxyglucose technique, it was revealed that the enhanced n.s.t. in the no-behaviour and the semi-restrained groups was accompanied by a significant increase of metabolic activity in the anterior part of the ventromedial hypothalamus. We conclude that during cold exposure motionlessness of slightly restrained animals increase n.s.t. when thermoregulatory behaviour to gain heat is not available. This increased n.s.t. is mediated by activation of hypothalamic function.

Animals↗
PubMed1986

Effect of amine on temperature-responsive neuron in slice preparation of rat brain stem.

Using slice preparations we investigated the effect of 5-hydroxytryptamine (5-HT) and norepinephrine (NE) on thermoresponsive neurons in the hypothalamus, midbrain, and the medulla oblongata. NE inhibits the activities of most of the warm-responsive neurons (11 out of 13 neurons) but 5-HT activates the warm-responsive neurons (10 out of 11 neurons) in the hypothalamus. However, the direction of neuronal response of the midbrain was opposite of that in the hypothalamus when 5-HT was applied. In the medulla oblongata, 5-HT facilitates both warm- and cold-responsive neurons and NE facilitates or inhibits these neurons in equal proportions. Furthermore, the dose-response relationships were determined using slice preparations. In the hypothalamus and the midbrain, NE and 5-HT started to effect the warm-responsive neurons at the minimum concentration of 5 X 10(-6) M, whereas the maximum responses were obtained at the concentration of 5 X 10(-5) M. In the medulla oblongata, NE or 5-HT changed the activities of the warm-responsive neurons in the range of 5 X 10(-5) to 10(-3) M or 10(-6) to 10(-5) M, respectively. It is concluded that the thermoresponsive neurons respond to 5-HT and NE in different ways, at both various levels in the central nervous system and the applied concentration of amines.

Action Potentials↗
PubMed1986

Stimulation of ventromedial hypothalamus induces cold defense responses in conscious rabbits.

The involvement of the ventromedial hypothalamus (VMH) in thermoregulatory responses, which include heat production and heat loss responses, was investigated by the method of electrical stimulation. Electrical stimulation of the VMH caused a rise in rectal temperature, accompanied by the enhancement of heat production: O2 consumption and shivering. In addition, a reduction in heat loss was observed, including decreases in skin temperature (Ts), respiratory rate, and body surface area resulting from a huddled posture. In this study, stimulation of the lateral hypothalamus and other regions near the VMH had no effect on thermoregulatory responses. beta-Blocker (propranolol, 1 mg/kg iv) injected 20 min before stimulation lessened O2 consumption by approximately 10% and attenuated the reduction in Ts during VMH stimulation, whereas alpha-blockade (phentolamine, 1 mg/kg iv) was ineffective. These results indicate that most of the increase in O2 consumption during VMH stimulation was due to the occurrence of shivering but that some component of it could be due to nonshivering thermogenesis. They also indicate that the VMH, either directly or by converging influences, is involved in the activation of thermoregulatory responses to cold stress.

Adrenergic beta-Antagonists↗
PubMed1986

Rat endogenous pyrogen and fever.

Rat endogenous pyrogen (EP), prepared from the white blood cells of lipopolysaccharide-pretreated rats, produced a fever in both rabbits and rats. The effects of human, rabbit, and rat EP on the body temperatures of rabbits and rats were investigated to clarify differences in the febrile response to each kind of EP. The latency to fever onset and the time to peak fever induced by rat EP in rabbits and rats were significantly greater than those induced by human and rabbit EP. The maximum elevation of the body temperature induced by rat EP in both animals was almost identical to that induced by human and rabbit EP. In a comparison of the febrile responses to various EPs between rabbits and rats, the latency to fever onset, the time to peak, and the maximum elevation of fever in rats were approximately half those observed for rabbits. Furthermore, the threshold dosage to induce a fever response in rats was greater than that necessary for rabbits. It is concluded that rat EP could be obtained by in vitro techniques and that rats have the physiological mechanisms to develop a fever through production of EP.

Animals↗