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Biomedical subjects

N Nagano

Publications and source records attributed to N Nagano.

At least 109 records · Page 6Linked to original sources
PubMed1991

Effects of antihypertensive treatment on cardiac hypertrophy and cardiac function in elderly hypertensive patients.

The effects of antihypertensive treatment with calcium antagonists or angiotensin-converting enzyme (ACE) inhibitors on the reversal of left ventricular hypertrophy and the left ventricular function in elderly hypertensive patients were examined. Twenty-four elderly hypertensive patients with cardiac hypertrophy, aged from 65 to 79 years (mean +/- SEM of 71 +/- 1 years), were treated with a calcium antagonist (nifedipine or nicardipine) or ACE inhibitor (captopril or enalapril) for 3 months. Thirteen patients had essential hypertension [EH: systolic blood pressure (SBP) greater than or equal to 160 mm Hg and diastolic blood pressure (DBP) greater than or equal to 90 mm Hg, aged 70 +/- 1 years] and 11 had isolated systolic hypertension (ISH:SBP greater than or equal to 160 mm Hg and DBP less than 90 mm Hg, aged 74 +/- 2 years). All patients underwent M-mode echocardiography to assess left ventricular mass index (LVMI) and left ventricular function (ejection fraction, EF) before and after 3 months of treatment. BP significantly decreased from 174 +/- 3/97 +/- 1 to 144 +/- 5/84 +/- 2 mm Hg in EH and from 167 +/- 3/82 +/- 2 to 144 +/- 4/74 +/- 2 mm Hg in ISH. The LVMI was also significantly reduced from 204 +/- 14 to 174 +/- 16 g/m2 in EH and from 179 +/- 14 to 156 +/- 12 g/m2 in ISH. EF showed no significant changes with treatment in either group. In elderly hypertensive patients, the antihypertensive treatment with calcium antagonist or ACE inhibitor reduced cardiac hypertrophy without any deterioration of left ventricular function in both essential hypertension and isolated systolic hypertension.

Aged↗
PubMed1991

Restriction endonuclease digest patterns of chromosomal DNA from group B beta-haemolytic streptococci.

Scanning densitometry and computer-assisted numerical analysis were used to examine restriction endonuclease digest patterns (RDPs) of chromosomal DNA from 26 infecting strains and 44 vaginal isolates of group B beta-haemolytic streptococci (GBS). At the 95% similarity level, HindIII RDPs of serotype Ia and III strains clustered into four and three RDP types, respectively. Nine of 10 strains from neonates with early-onset septicaemia belonged to two particular RDP types (Ia-3 and III-3). In contrast, serotype III GBS strains from meningitis cases were not characterised by particular RDP types. Associations between RDPs and certain phenotypic characteristics were also found.

Chromosomes, Bacterial↗
PubMed1991

Serological evidence that the Q fever agent (Coxiella burnetii) has spread widely among dairy cattle of Japan.

Serological examination of bovine and human sera for antibodies against Coxiella burnetti was carried out by the immunofluorescence technique. Twenty to 30% of the cows examined were antibody-positive. Sera from two veterinarians also had antibody against C. burnetii. These results suggest an increase in the number of infected cows with C. burnetii in Japan since 1954, and also imply the possibility of the prevalence of acute Q fever in the human population, which had been underestimated and undiagnosed for the last three decades.

Animals↗
PubMed1991

Does heparin inhibit renin activity?

Although heparin was reported in the 1960s to inhibit renin activity, this has not always been confirmed by other investigators. Hence, we re-examined whether heparin really inhibits renin or not. Renin activities were determined by radioimmunoassay of angiotensin I generated at pH 7.4. (i) No significant difference was found between the two kinds of plasma samples obtained with heparin and with EDTA as anticoagulant, in ARC (renin activity with addition of sheep renin substrate), TRC (ARC after activation of inactive renin by trypsin), or PRA (plasma renin activity without additional substrate). (ii) Even in higher concentrations of heparin up to 500 U/mL, neither PRA, ARC, nor TRC of plasma was affected significantly. (iii) Heparin, in concentrations up to 500 U/mL, exerted no significant effect on TRC of the media of human vascular smooth muscle cell culture. In conclusion, heparin does not exert any significant inhibitory effect on human renin nor does it affect activation of inactive renin by trypsin in the range of concentration of practical use, under the conditions employed in this study.

Edetic Acid↗
PubMed1991

Anticoagulant-related intracerebral hemorrhage in patients with prosthetic heart valves--report of two cases.

Two cases of intracerebral hemorrhage in patients with prosthetic heart valves receiving anticoagulant therapy without preceding embolic cerebral infarction are reported. Phytonadione and fresh frozen plasma were immediately given, and the intracerebral hematoma evacuated successfully. In one case, intractable bleeding occurred perioperatively until the thrombotest value reached 40% or more. This patient later developed fatal massive multiple intracerebral hemorrhages.

Adolescent↗
PubMed1991

Studies on beta-lactam antibiotics. II. Synthesis and antibacterial activity of cephalosporins with substituted 1,3-dithietane directly attached to the C-3 position.

Preparation of cephalosporins bearing a 1,3-dithietane ring attached to the C-3 position using intramolecular rearrangement are described. The diastereoisomers (6a-I and 6a-II) were separated by silica gel column chromatography. These 3-[4-(carbamoyl carboxymethylene)-1,3-dithietane-2-yl]cephems showed comparable activity against Gram-negative bacteria to that of ceftazidime.

Cephalosporins↗
PubMed1991

Studies on beta-lactam antibiotics. III. Syntheses and antibacterial activities of new 3-(1,3-dithiolan-2-yl)cephalosporins, YM-22508, YM-16457 and their prodrug-type esters.

The syntheses and biological activities of new 7-beta-[(Z)-2-(2-amino-4-thiazolyl)-2-hydroxy-iminoacetamido]-3-(1 ,3- dithiolan-2-yl)-3-cephem-4-carboxylic acid (YM-22508, 1a), 7-beta-[(Z)-2-(2-amino-4-thiazolyl)-2- methoxyiminoacetamido]-3-(1,3-dithiolan-2-yl)-3-cephem-4-carboxyli c acid (YM-16457, 1d) and their prodrug-type esters are described. Among them, YM-22561 (1c), the 1-acetoxyethyl ester of 1a, showed good in vivo efficacy in mice against infections of Staphylococcus aureus Smith, Streptococcus pyogenes S 23 and Escherichia coli NY-17 and a long plasma T1/2 in mice.

Animals↗
PubMed1990

Different spinal effects of opioid agonists on spinal and spino-bulbo-spinal reflexes in rats.

The effects of morphine-HCl (MOR), methionine-enkephalin (ME) and dynorphin (DYN) on spinal and spino-bulbo-spinal (SBS) reflexes were studied. Although spinal intrathecal administration of MOR (15 micrograms) did not produce any apparent effect on these reflexes, systemically administered MOR (3 mg/kg i.v.) reduced the electrical toe stimulation-induced SBS reflex. Furthermore, MOR (3 mg/kg i.v.) increased the polysynaptic reflex induced by electrical stimulation of low-threshold dorsal root afferents in intact (non-spinal) rats, but not in spinal rats. Intrathecally administered DYN (0.5 and 5 micrograms) reduced both the electrical toe stimulation-induced spinal and SBS reflexes, while ME (15 micrograms) only reduced the SBS reflex. These results indicate the physiological multiplicity of spinal opioid receptors. MOR may affect supraspinal nuclei but not the spinal pathway which possesses MOR-sensitive opioid receptors, whereas ME and DYN affect spinal opioid peptide receptors and modulate the reflex activities in which they participate.

Animals↗
PubMed1990

Effects of a new analog of thyrotropin-releasing hormone, N alpha-[(S)-4-oxo-2-azetidinyl) carbonyl]-L-histidyl-L-prolinamide dehydrate (YM-14673) on spinal reflex potentials and flexor reflexes in spinalized rats.

Experiments were performed on spinalized rats, transected at the Cl level. The intravenous administration of TRH and its analog YM-14673 (N alpha-[(S)-4-oxo-2-azetidinyl) carbonyl]-L-histidyl-L-prolinamide dehydrate) produced marked increases in the amplitude of mono- and polysynaptic reflex potentials and those of the withdrawal flexor reflexes. The effects of YM-14673 were stronger and longer-lasting than those of TRH. The stimulant action of TRH and YM-14673 on the flexor reflexes was not antagonized by prazosin, chlorpromazine, haloperidol or cyproheptadine, suggesting no involvement of the release of catecholamines or serotonin in the stimulant effects of TRH and its analog. Therefore, YM-14673 may be beneficial for the treatment of several spinal motor neuron diseases.

Animals↗
PubMed1990

Effect of recombinant human erythropoietin on new anaemic model rats induced by gentamicin.

The effects of recombinant human erythropoietin (r-HuEPO) on haematological parameters were studied in rats in which uraemia and anaemia had been induced by gentamicin, an aminoglycoside antibiotic and a nephrotoxic agent. After the occurrence of slight polycythaemia, the red blood cell count, haematocrit and haemoglobin concentration decreased by 20-30% compared with those of the control (saline-injected) rats. At the end of gentamicin treatment, the endogenous serum EPO level had decreased to about 40% compared with that of control rats. Gentamicin-treated rats showed marked elevation of blood urea nitrogen, extensive tubular necrosis in the kidney and haemosiderin deposition in the spleen. In the osmotic fragility test, the fragility of erythrocytes significantly increased compared with that of control rats. These findings indicate that the anaemia induced by gentamicin is due not only to a deficiency of EPO but also to an enhancement of fragility of erythrocytes in an azotaemic environment. The administration of r-HuEPO during anaemia markedly increased red blood cell count, haematocrit and haemoglobin concentration. It is suggested that a gentamicin-treated rat is a useful and convenient anaemic model and r-HuEPO is useful for treatment of anaemia in acute renal failure.

Anemia↗
PubMed1990

[Transarterial hepatic embolization of metastatic liver cancers with reference to 17 cases of survival for more than 2 years].

The evaluation of TAE was studied for 73 patients with metastatic liver cancers but without metastasis in other organs, who were treated with initial TAE more than 2 years ago. Seventeen patients survived for more than 2 years. The primary lesions consisted of colon cancer in 9 patients, the Langerhans islet cell tumor of the pancreas in 4, gastric cancers in 2, breast cancer in 1 and leiomyosarcoma of the colon in 1. The overall 2-year survival rate calculated by the direct method was 23.3% and mean survival period was 15.8 months. The prognosis was good in H1 and V3. Lp-TAE produced better effects but no statistically significant difference was found between the 2-year survivals by Lp-TAE and by GS-TAE.

Adult↗
PubMed1990

[CT evaluation of blow-out fractures].

Fifty patients with blow-out fracture were analysed in detail by using CT. Among these cases, 38 and 12 cases were classified as pure type and impure type fractures, respectively. The lesion of pure type noted in five positions of the orbit; floor, roof, medial wall, corner, and floor with medial. The shape of fracture fragments were observed as trap door, punched out, broad and linear in floor type fracture. Herniated ophthalmic muscles were detected in approximately half of the pure type fractures. CT scan plays an important role in the decision to operate on blow-out fracture.

Adolescent↗
PubMed1989

Sialic acid levels and lag time of growth in chemically defined medium containing 200 mM phosphate among strains of various serotypes of Streptococcus agalactiae.

The type-specific capsular polysaccharide antigen of Streptococcus agalactiae has in previous experimental studies been considered a significant antiphagocytic factor, whereas the lipoteichoic acid moiety has been suggested to be a factor in adherence to human fetal cell lines. Since epidemiological data concerning these cell constituents in strains from the genital tract are lacking, we attempted serotyping and analysis of these constituents of 100 vaginal isolates. The capsular polysaccharide level was shown to be the amount of sialic acid that occupied the terminal side chains of the polysaccharide. We carried out a study to ascertain whether strains exhibited a lag time of growth in a chemically defined medium containing 200 mM phosphate, which has been suggested to be characteristic of strains with high lipoteichoic acid levels. Strains were classified, on the basis of the results of distribution of sialic acid levels, into three categories: (i) strains with a low sialic acid content of equal to or less than 9 micrograms/mg of cell dry weight; (ii) strains with a moderate sialic acid content of more than 9 but less than 12 micrograms/mg of cell dry weight; and (iii) strains with a high sialic acid content of equal to or more than 12 micrograms/mg of cell dry weight. Strains that belonged to the last category, which, as previous experimental data indicate, are potentially virulent strains, were significantly distributed among isolates of types Ia (P less than 0.001) and III (P less than 0.05). On the other hand, strains exhibiting a lag time of growth in the above-mentioned medium were detected to a significant extent in type III isolates (P <0.02). These results may be related to the epidemiological finding that isolates from neonates with late-onset infection were more frequently serotype Ia and III isolates.

Adult↗
PubMed1989

Screening of type Ia and Ib Streptococcus agalactiae strains with high sialic acid levels by determination of susceptibility to tetracyclines.

The type-specific capsular polysaccharide antigen of Streptococcus agalactiae is recognized to be an antiphagocytic factor in strains having large amounts of it. In the present study, it was indicated that vaginal isolates of types Ia and Ib could be classified into two groups on the basis of both their levels of the sialic acid, which occupies the terminal side chains of the polysaccharide, and their susceptibility to tetracyclines: one group comprised strains with low sialic acid levels (less than 9 micrograms/mg of cell dry weight) as well as with susceptibility to tetracyclines (MIC, less than or equal to 0.5 micrograms/ml), and the other comprised strains with higher sialic acid levels (greater than or equal to 9 micrograms/mg) and resistance to tetracyclines (MIC, greater than or equal to 8 micrograms/ml). A few isolates were found to have low levels of sialic acid and to be resistant to tetracyclines, but no isolates that were both relatively high in sialic acid and susceptible to tetracyclines were ever detected. Among strains of those serotypes, the MICs of tetracyclines were not in proportion to the sialic acid levels and were not affected when the sialic acid levels of each strain were altered by using Todd-Hewitt broth with various concentrations of Na2HPO4 and glucose. It was, therefore, apparent that the correlation of sialic acid levels with susceptibility to tetracyclines was not related directly to the sialic acid content or to the amount of the capsular polysaccharide. Since no plasmid DNAs were detected among representative strains that were tetracycline resistant, it was apparent that at least for the strains tested, resistance was chromosomal gene associated. In strains of S. agalactiae of types of Ia and Ib, the determination of susceptibility to tetracyclines was considered to be useful for screening strains with higher sialic acid levels.

Culture Media↗
PubMed1989

[Multiple cerebral venous angiomas associated with mixed pial and dural arteriovenous malformation].

Venous angioma is a relatively rare entity of vascular malformations of the brain and usually found as a solitary lesion. Cases of multiple lesions and/or coupled with other vascular malformations are extremely rare. We present the first case of multiple supratentorial venous angiomas associated with mixed pial and dural arteriovenous malformation (AVM) fed by the posterior cerebral artery, the occipital artery and the posterior meningeal artery.

Adolescent↗