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Biomedical subjects

H Higashi

Publications and source records attributed to H Higashi.

At least 163 records · Page 9Linked to original sources
PubMed1991

Present mercury levels in red blood cells of nearby inhabitants about 30 years after the outbreak of Minamata disease.

Samples of red blood cells (RBCs) from 1178 inhabitants, consisting of 546 males and 795 females (over 40 years old), of a coastal town near Minamata City were analyzed for total mercury. The mercury concentrations in the RBCs showed lognormal distributions for both sexes with higher values in males than in females. The geometric mean of the mercury concentrations in the RBCs was 27.5 ng/g (ranging from 8.0 to 69.1 ng/g) for males and 20.4 ng/g (ranging from 7.0 to 63.7 ng/g) for females. The mercury concentrations in the RBCs decreased with advancing age. A significant regression between the geometric mean of the mercury concentrations in the RBCs and age was obtained for both sexes. The mercury concentrations in the RBCs from male inhabitants of the coastland area were significantly higher than those from male inhabitants of the inland area. In terms of occupation, the highest mercury concentrations were observed in the RBCs from fisherman. No significant difference in the present mercury concentrations in the RBCs was observed between the cases with Minamata disease and the controls.

Aged↗
PubMed1991

Cloning and sequencing of the 7 alpha-hydroxysteroid dehydrogenase gene from Escherichia coli HB101 and characterization of the expressed enzyme.

The 7 alpha-hydroxysteroid dehydrogenase (EC 1.1.1.159) gene from Escherichia coli HB101 was cloned and expressed in E. coli DH1. The hybrid plasmid pSD1, with a 2.8-kbp insert of chromosomal DNA at the BamHI site of pBR322, was subcloned into pUC19 to construct plasmid pSD3. The entire nucleotide sequence of an inserted PstI-BamHI fragment of plasmid pSD3 was determined by the dideoxy chain-termination method. Within this sequence, the mature enzyme protein-encoding sequence was found to start at a GTG initiation codon and to comprise 765 bp, as judged by comparison with the protein sequence. The deduced amino acid sequence of the enzyme indicated that the molecular weight is 26,778. The transformant of E. coli DH1 harboring pSD3 with a 1.8-kbp fragment showed about 200-fold-higher enzyme activity than the host. The enzyme was purified by a single chromatography step on DEAE-Toyopearl and obtained as crystals, with an activity yield of 39%. The purified enzyme was homogeneous, as judged by sodium dodecyl sulfate gel electrophoresis. The enzyme was most active at pH 8.5 and stable between pH 8 and 9. The enzyme was NAD+ dependent and had a pI of 4.3. The molecular mass was estimated to be 120 kDa by the gel filtration method and 28 kDa by electrophoresis, indicating that the enzyme exists in a tetrameric form.

Amino Acid Sequence↗
PubMed1991

Membrane properties of guinea pig cingulate cortical neurons in vitro.

1. The passive and active membrane properties of guinea pig cingulate cortical neurons were studied in vitro using the slice preparation. Results were reported for intracellular recordings made from neurons that were penetrated in layers V/VI of the anterior cingulate cortex areas 1 and 3. 2. The neurons had an average resting potential of -71 mV, an input resistance of 71 M omega, a spike amplitude of 93 mV, and a spike duration of 1.6 ms. The firing occurred regularly at an average rate of 13 spikes/s at the membrane potential of -55 mV, suggesting that they are probably regular spiking pyramidal cells. 3. The voltage decay following a hyperpolarizing current pulse could always be fitted by two exponentials in most cells. The slope of the charging function was analyzed to estimate the two cable theory parameters of the neurons, based on a simple Rall model: the electrotonic length (LN) of the equivalent dendritic cylinder and the conductance ratio (rho) of the dendrites to that of the soma. There were no significant differences in the LN (0.9-1.1) and the rho (2.8-3.0) of neurons in normal media and solutions containing tetrodotoxin (TTX), Cs+ and low Ca2+, indicating that the neurons may be electrically compact. 4. In most cells the steady-state current-voltage (I-V) relationship revealed three distinct types of rectification: an anomalous inward rectification in the hyperpolarizing direction, a subthreshold inward rectification, and a delayed outward rectification in the depolarizing direction. 5. The anomalous rectification was increased in high K+ solutions and was decreased in low K+ solutions. Analysis of the Ba2+ and Cs+ sensitivity confirmed that the anterior cingulate neurons had two distinct types of anomalous rectification, one that was time dependent and Ba2+ insensitive and the other that was fast and Ba2+ sensitive. Ionic analyses indicated that the time-dependent anomalous rectification was due to an increased permeability to both Na+ and K+, whereas the fast, Ba(2+)-sensitive rectification was probably only K+ dependent. 6. The subthreshold inward rectification was depressed by TTX, lidocaine, or Co2+, as well as the reduction of extracellular Na+, whereas it was augmented by extracellular Ba2+. This persistent Na(+)-Ca2+ conductance triggered the generation of Na(+)-dependent action potentials. 7. The delayed outward rectification was recorded in the potential range between -65 and -20 mV.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Synaptic responses of guinea pig cingulate cortical neurons in vitro.

1. Intracellular recordings were made from layer V/VI neurons of the guinea pig anterior cingulate cortex to investigate postsynaptic potentials (PSPs) evoked by electrical stimulation of the subcortical white matter (forceps minor). 2. Four distinct types of PSPs were recorded (at the resting potential) under normal physiological conditions; 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX)-sensitive excitatory postsynaptic potentials (EPSPs) were followed by bicuculline- or picrotoxin-sensitive depolarizing or hyperpolarizing inhibitory postsynaptic potentials (IPSPs), which were further followed by phaclofen-sensitive, long-lasting hyperpolarizing postsynaptic potentials (LPSPs). The average times-to-peak for the EPSP, depolarizing and hyperpolarizing IPSPs, and LPSP were 10, 22, 28, and 146 ms, respectively. 3. In the presence of CNQX and bicuculline, high-intensity electrical stimulation elicited a longer lasting EPSP with a time-to-peak of 21 ms. The amplitude and duration of the EPSP decreased with membrane hyperpolarization and increased with membrane depolarization. The EPSP was reversibly abolished by D,L-2-amino-5-phosphonovaleric acid (D,L-APV). 4. The bicuculline- or picrotoxin-sensitive depolarizing and hyperpolarizing IPSPs and the phaclofen-sensitive LPSP were markedly suppressed by CNQX, suggesting that glutamate (Glu) and/or aspartate nerve terminals project to GABAergic interneurons, and that the GABAergic interneurons are activated mainly by non-N-methyl-D-aspartate (non-NMDA) receptors. 5. In the presence of picrotoxin, the average reversal potential for the compound EPSP was 0 mV, which was similar to that (-6 mV) for the Glu-induced depolarization. In a solution containing D,L-APV at low concentrations, the average reversal potentials for the depolarizing and hyperpolarizing IPSPs and for the early and late components of the gamma-aminobutyric acid (GABA)-induced responses were -62, -72, -70, and -61 mV, respectively. Thus the value for the depolarizing IPSP was similar to that for the late response to GABA, whereas the value for the hyperpolarizing IPSP was almost the same as that for the early response to GABA. The average reversal potential of -90 mV for the LPSP was similar to -93 mV for the baclofen-induced hyperpolarization and to -94 mV for the spike afterhyperpolarization. 6. Application of phaclofen decreased the interspike interval of the spontaneous firing and reversed the increase in the interspike interval after subcortical stimulation. This result indicates that, even in a slice preparation, the anterior cingulate neurons are under tonic inhibitory control exerted by spontaneously active GABAergic interneurons.(ABSTRACT TRUNCATED AT 400 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1991

Synaptic responses of guinea pig and rat central amygdala neurons in vitro.

1. To investigate postsynaptic potentials (PSPs), we made intracellular recordings from neurons of the amygdaloid central nucleus in slices from the guinea pig and rat brains maintained in vitro. The results from guinea pigs and rats were very similar. 2. In the presence of bicuculline (20 microM), focal electrical stimulation of the amygdaloid basal nucleus with low intensities elicited short-latency excitatory PSPs (EPSPs) followed by long-latency EPSPs. The short-latency EPSP was selectively blocked by 6-cyano-7-nitroquinoxaline-2,3-dion (CNQX; 10-20 microM). The long-latency EPSP was preferentially abolished by D,L-2-amino-5-phosphonovaleric acid (D,L-APV; 40 microM) and was augmented by removal of extracellular Mg2+. The compound EPSP reversed at -4 mV, which was close to -1 mV, the reversal potential for pressure-ejected glutamate (Glu). 3. When the intensity of the focal stimulation was increased in the presence of bicuculline (20 microM), CNQX (20 microM), and D,L-APV (50 microM), a second EPSP with a short latency and a prolonged duration could be evoked in approximately 65% of the neurons. The EPSPs were reversibly blocked by d-tubocurarine (50 microM) or hexamethonium (200 microM) but were unaffected by atropine (1 microM) or a 5-hydroxytryptamine type 3 receptor antagonist, ICS-205930 (5-10 microM). In these neurons, acetylcholine (ACh; 1-3 mM) caused a depolarization, associated with a decreased input resistance. 4. In the presence of CNQX (20 microM) and D,L-APV (50 microM), single focal stimulation of the dorsolateral subdivision in the central nucleus with low intensities elicited a depolarizing inhibitory PSP (IPSP). The IPSP was reversibly abolished by bicuculline (20-40 microM). The reversal potential (-63 mV) for the IPSP was similar to the reversal potential (-61 mV) for the response to gamma-aminobutyric acid (GABA) applied by pressure ejection. 5. In the presence of bicuculline (20-40 microM) and CNQX (20 microM), a repetitive focal stimulus with high intensities delivered to the dorsolateral subdivision produced a hyperpolarizing PSP followed by a slow depolarization in most neurons. Of putative inhibitory amino acid transmitters, glycine (Gly; 3 mM) produced only a hyperpolarization, associated with a decrease in input resistance. Strychnine (1-2 microM) reversibly blocked both the Gly hyperpolarization and the synaptically evoked hyperpolarization. The reversal potential of -81 mV for the hyperpolarizing PSP was close to -82 mV for the Gly hyperpolarization. The reversal potential for the Gly response was shifted to less negative values by increasing the external K+ concentration or decreasing the extracellular Cl- concentration.(ABSTRACT TRUNCATED AT 400 WORDS)

2-Amino-5-phosphonovalerate↗
PubMed1991

Problems of protocol practice in Japan.

With progress in medical knowledge and in the technology of medical care, the contents of medical practice have become increasingly complicated year by year. The protocol practice (clinical algorithms or scheduled care) has been experimentally employed as one of medical-practice systems aimed at providing better medical care and maintaining its high standards. In the protocol practice the criteria for decision-making, which are clinically employed, are precisely made up in advance so that practice will be performed systematically. The WHO has recommended this protocol practice as a medical-care system appropriate for realizing clinical experiments. In recent years a number of clinical studies have been born from the protocol practice and, thus, it has been considered to be a formula for conducting clinical experiments tolerant of scientific criticism. The protocol practice, however, since it is difficult to conduct smoothly, has not yet been settled. This study aims at considering what we should do to make the protocol practice system settled through the observation of pitfalls in the course of its application.

Clinical Medicine↗
PubMed1991

A 24-hour ordering system for clinical examinations.

We have developed a 24-hour ordering system for clinical examinations, making use of the features of multi-function workstation (IBM5550) which performs two functions both in an on-line terminal and in a personal computer. It is used as an on-line terminal for the host computer (IBM4381) in day time. At night or on holiday, it is used as a stand-alone type personal computer to order clinical examinations. For this purpose, basic information of the inpatients (patient number, name, sex, date of birth, clinic, ward) are transferred from the host computer to the disket in the workstation in the evening when host computer finished on-line service. A physician can input the patient number followed by examination items using the touch panel according to the dialogue type guides written in Chinese character. Then, specimen label, list of ordered tests and an order form are printed out instantly. The date (patient number, examination items, identification number of the specimen, etc.) stored in the disket in the workstation at night are transferred from workstation to the host computer next morning. The host computer merges the information ordered in day time and at night and supplies working documents for examination (worksheets, master log, etc.) to technicians. Thus physicians can order examinations all day long using workstation, which make it possible to spare the time.

Clinical Laboratory Information Systems↗
PubMed1991

[Clinical evaluation of cefpirome in children].

Cefpirome (CPR, HR 810) was clinically evaluated for its efficacy and safety in 11 patients with ages from 4 months to 11 years with bacterial infection. The results obtained are summarized as follows. 1. CPR was administered to 6 patients with bronchopneumonia, a patient with pneumonia, a patient with tonsillitis, 2 patients with acute pharyngitis and a patient with suppurative parotitis at daily dosage levels ranging 55.5-91.7 mg/kg, divided into 3 using intravenous bolus injection or 30 minutes drip infusion. Clinical responses of the 11 patients were as follows: excellent; 8 patients, good; 2 patients, poor; 1 patient, hence the efficacy rate was 90.9%. 2. Neither clinical adverse reaction nor abnormal laboratory test value was observed except slight elevation of GOT and GPT in a patient and leukopenia in another. 3. MICs of CPR against 18 beta-lactamase producing strains isolated from patients were as follows. MIC against a strain of Staphylococcus aureus was 1.56 micrograms/ml, MICs against 3 strains of Klebsiella pneumoniae were less than 0.025 microgram/ml, those against 3 out of 5 strains of Enterobacter cloacae were less than 0.025 microgram/ml and those against the remaining 2 strains were 0.05 and 0.20 micrograms/ml. MICs against 2 out of 3 strains Acinetobacter lwoffi were 1.56 micrograms/ml, and that of the remaining 1 strain was 0.39 microgram/ml. MICs against 2 strains of Pseudomonas cepacia were 1.56 micrograms/ml. MICs against a strain of Pseudomonas putida and a strain of Citrobacter diversus were 0.78 and less than 0.025 microgram/ml, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1990

Two-dimensional mapping by the high-performance liquid chromatography of oligosaccharides released from glycosphingolipids by endoglycoceramidase.

A two-dimensional sugar mapping method has been developed by which sensitive, reproducible, and simple analysis can be carried out on the structures and compositions of oligosaccharides released from glycosphingolipids by endoglycoceramidase. The oligosaccharides were labeled quantitatively with an ultraviolet-absorbing compound, p-aminobenzoic acid ethyl ester (ABEE). The ABEE-oligosaccharides were separated first on an amide-silica column and then on a C4-silica column by high-performance liquid chromatography. The acidic ABEE-oligosaccharides were eluted as a group at the start of the chromatography while the neutral ABEE-oligosaccharides were separated according to size and structure on an amide-silica column using an eluent without salt. The acidic oligosaccharides were separated according to size and structure when rechromatographed on the same column using an eluent containing KH2PO4. NeuAc-containing ABEE-oligosaccharides were extensively separated from the corresponding NeuGc derivatives. The ABEE-oligosaccharides separated on an amide-silica column were then chromatographed on a column of C4-silica on which lactotriose and neolacto-series oligosaccharides were clearly shown to be separated from the others. On the basis of the retention times of the individual ABEE-oligosaccharides on two separate columns, 9 neutral and 15 acidic oligosaccharides derived from glycosphingolipid standards were two-dimensionally mapped without overlapping. The gangliosides of a human chondrosarcoma tissue and glycosphingolipids of tumor tissue of FBJ virus-transformed murine osteosarcoma cells were analyzed by this method in conjunction with exoglycosidase treatment. At least 11 species of glycosphingolipids were identified in both cases.

Animals↗
PubMed1990

Development of colon cancer after liver transplantation for primary sclerosing cholangitis associated with ulcerative colitis.

Between February 26, 1981, and July 30, 1987, 36 patients underwent orthotopic liver transplantation for primary sclerosing cholangitis associated with ulcerative colitis. Three of the 36 recipients died within 3 mo because of graft nonfunction or surgical complications. The other 33 (92%) lived for at least 1 yr. Two of the 33 died after 12 and 14 mo, respectively, of recurrent cholangiocarcinoma that was not diagnosed before transplantation. Four other patients died of recurrent liver failure (three cases) or immunoblastic sarcoma (one case) after 14, 21, 36 and 44 mo. Twenty-seven (75%) of the patients are still alive 23 to 81 mo after transplantation. Two patients have been diagnosed as having colorectal cancer 11 and 21 mo respectively, after transplantation, for an overall incidence of 5.6% (2 of 36) and a corrected incidence of 6.5% (2 of 31) if the three early deaths and two later deaths caused by cholangiocarcinomas are excluded. It is not known whether colorectal malignancies were present but undetected at the time of transplantation or whether they developed afterward. It is clear that patients who undergo liver transplantation for primary sclerosing cholangitis associated with ulcerative colitis should have careful follow-up of the colon, including colonoscopy and multiple biopsies of the colorectal mucosa. Whether proctocolectomy should be considered prophylactically after liver transplantation is an unresolved issue.

Adenocarcinoma↗
PubMed1990

Calcium-dependent potentials with different sensitivities to calcium agonists and antagonists in guinea-pig hippocampal neurons.

Effects of organic Ca channel blockers, Ca channel activators and omega-conotoxin on guinea-pig hippocampal CA1 neurons in vitro preparations were studied with intracellular recording methods. Most of the Ca channel blockers, such as prenylamine, D 600, flunarizine, nifedipine, cinnarizine and nicardipine (0.2-4 microM), raised the threshold for Na-dependent spike generation and decreased the amplitude of the spike afterhyperpolarization. Verapamil (5 microM) and diltiazem (5 microM) did not significantly alter the threshold and amplitude of the Na spike. Action potentials elicited in the presence of either tetrodotoxin (0.5 microM) and tetraethylammonium (20 mM) or tetrodotoxin (0.5 microM) and Ba (1.25 mM) consisted of an initial spike component followed by a long depolarization. Both responses were abolished by addition of Co (2 mM) or Cd (0.25-0.5 mM), or by superfusion with a low Ca (0.25 mM)-high Mg(15 mM) medium, indicating that the potentials resulted from Ca entry. The Ca-dependent slow depolarization was preferentially blocked by most of the organic Ca channel blockers at approximately one-third the concentrations (0.1-2 microM) which were required to shorten the Ca spike. When the cell in a solution containing tetrodotoxin (0.5 microM), Co (2 mM) and 4-aminopyridine (2 mM) was hyperpolarized and then depolarized by passing current pulses across the membrane, a transient depolarizing hump occurred on the decay phase of the electrotonic potential. This transient depolarization was abolished by Co (2 mM), Ni (2 mM) or most of the organic Ca channel blockers (0.2-5 microM). Diltiazem (5 microM) did not significantly change these Ca-dependent potentials. The evoked excitatory postsynaptic potential was very resistant to the Ca channel blockers. Approximately 2-10 times higher concentrations (0.5-3 microM) were necessary to decrease the excitatory postsynaptic potential amplitude than to shorten the Ca spike. On the other hand, the minimal concentrations and order of potencies of the Ca channel blockers for depressing the evoked inhibitory postsynaptic potential and for elevating the threshold for Na spike generation were almost the same. Dihydropyridine Ca channel activators, such as Bay K 8644, CGP 28 392 and YC 170 at low concentrations (0.1-1 microM), decreased the Ca spike, the Ca-dependent slow depolarization and the evoked synaptic potentials, while the substances augmented the Ca-dependent transient depolarization. On the other hand, omega-conotoxin (5 microM) reversibly depressed the Ca spike and slow depolarization to the same degree, without affecting the transient depolarization and the evoked excitatory or inhibitory postsynaptic potentials.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1990

Hemodynamic and biochemical changes during normothermic and hypothermic sanguinous perfusion of the porcine hepatic graft.

Using an ex vivo liver sanguinous perfusion system, hemodynamic and biochemical changes of the porcine livers were studied, which were preserved cold (4 degrees C) for 24 hr in University of Wisconsin solution and reperfused with normothermic (37 degrees C) (n = 8) or hypothermic (32 degrees C) (n = 8) blood for 3 hr. Six more livers were reperfused with normothermic blood (37 degrees C) immediately after procurement as controls. The total hepatic blood flow was adjusted to 1 ml/min/g liver weight, in which hepatic artery and portal vein flows were administered at a 1:2 ratio. In livers stored cold for 24 hr in UW solution and perfused normothermically, a statistically higher hepatic artery resistance was exhibited at 30 and 60 min after reperfusion (P less than 0.05), and there was lower bile output (P less than 0.05) at 90 and 120 min as compared to the controls. In livers stored cold for 24 hr in UW solution and perfused hypothermically, as compared to ones perfused normothermically, statistically higher hepatic-artery and portal-vein resistances (P less than 0.05) were observed throughout the perfusion period and 60 min after reperfusion, respectively. In addition, bile output and oxygen consumption of these livers were statistically lower than those of ones perfused normothermically (P less than 0.05). In contrast, chemistries of the perfusate of livers perfused hypothermically were comparable to ones perfused normothermically. Histologic examination of the liver perfused hypothermically demonstrated hepatic arterial and/or portal venous congestion and mild-to-moderate hemorrhage in the portal triads. This study suggests that livers preserved for a prolonged period of time demonstrate a high hepatic arterial resistance shortly after revascularization, and that recipient hypothermia after revascularization may be a risk factor for the development of hepatic arterial thrombosis following liver transplantation.

Animals↗
PubMed1990

Development of an automatic medical summary report system.

We developed a medical summary report system. In this system, each department can specify the predetermined conditions for issuing the summary report. The summary is made through a hierarchical database in the integrated hospital information system according to the predetermined conditions. The summary automatically issued after reception of the outpatient, or also issued by on-line summary report program with the patient number if requested by doctors. The report is sent to the proper consulting room from the reception desk using an air-shooter. The report contains the patient information such as a patient name, age, sex, birthday, a clinic name, a chart number, a patient number, diagnoses and examinations. The doctors can refer to the points of the clinical history of the patient in his own and other departments, and make a correct diagnoses and avoid the overlaps of the examinations and medications. This system has contributed to the quality-up of the patient care by availability of patient information even in other departments without the medical chart.

Hospital Information Systems↗
PubMed1990

A disposable patient identification card made of a paper.

This paper describes a patient identification system with a disposable paper card. In general, total costs of cards themselves, equipments and personnel are remarkable, not negligible for the hospital management. Therefore, a disposable identification cards made of a paper were issued to out-patients in our hospital. Many order forms were integrated into only one sheet. Patient identification data were printed on this sheet by a computer system when a patient came to the reception desk, and quickly transmitted to physicians. We could save the hospital costs and printing works by physicians, and also shorten the waiting time of patients at reception desks.

Ambulatory Care Information Systems↗
PubMed1990

Bioenergy status of human liver during and after warm ischemia.

Changes in the human liver's cellular bio-energy status during warm ischaemia and the subsequent blood reflow period were investigated by means of adenosine triphosphate (ATP) assay. In 8 patients, the average level of ATP in the liver tissue decreased significantly (p less than 0.05) from 28.7 +/- 8.6 mumol/g protein to 19.1 +/- 8.7 mumol/g protein within 10 minutes of warm ischemia. The pattern of decline in ATP levels did not correlate with clinical parameters, including presence of cirrhosis, liver function, type of ischemic method employed and postoperative complications. After reperfusion, ATP levels increased rapidly from 15.1 +/- 8.9 mumol/g protein to 19.6 +/- 8.2 mumol/g protein within 10 minutes, although the difference was not statistically significant. These patients' postoperative course was uneventful, and the results of serum chemistry tests were normal. The present study demonstrates a direct correlation between the levels of tissue ATP and the status of the liver's blood supply.

Adenosine Triphosphate↗