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Biomedical subjects

H Haraguchi

Publications and source records attributed to H Haraguchi.

At least 37 records · Page 2Linked to original sources
PubMed1997

Respiratory stimulation and generation of superoxide radicals in Pseudomonas aeruginosa by fungal naphthoquinones.

The mechanism of action of antimicrobial naphthoquinones from the fungus Fusarium was studied by using Pseudomonas aeruginosa. Bostricoidin, methyl ether fusarubin, and fusarubin stimulated the oxygen consumption of bacterial cells and induced cyanide-insensitive oxygen consumption. These activities of the tested compounds were also observed in bacterial membrane preparations in a dose-dependent manner. Naphthoquinones stimulated the generation of superoxide anion and hydrogen peroxide. The naphthoquinone effectively acted as the electron acceptors for bacterial diaphorase, which could explain the antibacterial activity of Fusarium naphthoquinones since electron acceptors lead to the stimulation of respiratory activity and the generation of oxygen radical species.

Anti-Bacterial Agents↗
PubMed1997

Antioxidative constituents in Heterotheca inuloides.

Sesquiterpenoids, 7-hydroxy-3,4-dihydrocadalin and 7-hydroxycadalin, and flavonoids, quercetin, kaempferol and their glycosides, isolated from Heterotheca inuloides (Asteraceae), a Mexican medicinal plant known as "arnica", were evaluated as antioxidants. These compounds showed potent scavenging activity on diphenyl-p-picrylhydrazyl (DPPH) radical. Microsomal lipid peroxidation induced by Fe(III)-ADP/NADPH was inhibited by both terpenoids and flavonoids, though only flavonoids possessed superoxide anion scavenging activity in microsome. Flavonoids also scavenged enzymatically and non-enzymatically generated superoxide anion. On the other hand, mitochondrial lipid peroxidation induced by Fe(III)-ADP/NADH was inhibited only by sesquiterpenoids. Furthermore, these terpenes protected mitochondrial enzyme activity against oxidative stress. These results showed that two types of antioxidants existed in the dried flower of H. inuloides and would contribute to protection of tissues against various oxidative stresses.

Animals↗
PubMed1997

Vestibular schwannoma showing a dural tail on contrast-enhanced magnetic resonance images.

The dural tail on contrast-enhanced magnetic resonance (MR) images, frequently observed in meningiomas, has been used to distinguish between cerebellopontine angle meningiomas and vestibular schwannomas. We report on a 66-year-old female with vestibular schwannoma showing the dural tail on contrast-enhanced MR images. Histological examination revealed that the dural tail corresponded to the thickened dura mater comprising of collagen fibres and scattered hyalinization with no tumoral invasion.

Aged↗
PubMed1997

Antioxidative action of diterpenoids from Podocarpus nagi.

Diterpenoids, totarol (1), totaradiol (2), 19-hydroxytotarol (3), totaral (4), 4 beta-carboxy-19-nortotarol (5), sugiol (6), isolated from Podocarpus nagi, were evaluated as antioxidants. Microsomal lipid peroxidation induced by Fe(III)-ADP/NADPH and mitochondrial lipid peroxidation induced by Fe(III)-ADP/ NADH were inhibited by these terpenoids. They inhibited linoleic acid autoxidation but not generation of superoxide anion. Totarol (1) protected mitochondrial respiratory enzyme activities against NADPH induced oxidative injury. Totarane diterpenes from P. nagi were shown to be effective to protect biological systems and function against various oxidative stresses.

Abietanes↗
PubMed1997

Antiperoxidative activity of neolignans from Magnolia obovata.

Honokiol and magnolol, neolignans in Magnolia obovata, have been evaluated as antioxidants. Microsomal lipid peroxidation induced by Fe(III)-ADP/NADPH and mitochondrial lipid peroxidation induced by Fe(III)-ADP/NADH were inhibited by these compounds. These neolignans protected mitochondrial respiratory chain enzyme activity against NADPH-induced peroxidative stress and protected red cells against oxidative haemolysis. The anti-oxidative activity of honokiol was more potent than that of magnolol. Neolignans in M. obovata were shown to be effective in protecting biological systems and functions against oxidative stress.

Animals↗
PubMed1997

Single-trial analysis of P3 in patients with generalized epilepsy.

The latencies and amplitudes of averaged P3, and the latencies, amplitudes and frequency components of single EEG responses to target tones were analyzed in 9 control subjects (CS group), 6 epileptics whose mean IQ was 100 (EP group) and 6 epileptics whose mean IQ was 52 (RE group), using an auditory oddball task. All of the subjects responded to the target tones correctly and there were no differences in the incidence of error in response to the target tones, or in the latencies and amplitudes of the averaged P3 among the three groups. However, the reaction times (RTs) in the RE group were significantly longer than those in the other groups (P < 0.05). Single EEG responses to target tone (single-trial ERPs) were classified into 2 types, those with and those without the P3 component. Type 1 had the P3 component and was observed in 42% of all of the responses in the RE group, significantly less than those in the CS (64%) and EP (61%) groups. The peak latencies of P3 in type 1 were similar among the three groups, but the amplitudes of P3 in type 1 in the RE group were significantly greater than those in the CS and EP groups. RTs in the RE group were significantly longer than those in the other groups, and had no correlation with the P3 latencies of type 1. There was little difference in the results of the frequency analysis among the three groups. These results suggest that all subjects in three groups recognized the target tones correctly, but they did not evaluate every target tone, since the incidence of P3 was almost 60% in the CS and EP groups, and 40% in the RE group. The characteristics of cognition and evaluation in three groups were the same, but the decrease in incidence of evaluation and the dissociation between the cognition and the response execution might be caused by impairment of the subject-environment contact mechanism, which resulted in the decrement of IQ in the RE group.

Acoustic Stimulation↗
PubMed1997

Inhibition of aldose reductase and sorbitol accumulation by astilbin and taxifolin dihydroflavonols in Engelhardtia chrysolepis.

Dihydroflavonol taxifolin and its glycoside, astilbin, from Engelhardtia chrysolepis inhibited rat lens and recombinant human aldose reductase. Taxifolin also inhibited sorbitol accumulation in human red blood cells. Furthermore, this dihydroflavonol aglycone maintained the clarity of rat lens incubated with a high concentration of glucose. These dihydroflavonols may be effective for preventing osmotic stress in hyperglycemia.

Aldehyde Reductase↗
PubMed1997

Clinical global measures of dementia. Position paper from the International Working Group on Harmonization of Dementia Drug Guidelines.

Following is the report of the committee working on clinical global measures for antidementia drug guidelines. The concepts involved in global scales, the distinctions between change and severity scales, advantages and disadvantages of structured interviews, and anchoring of change scores are discussed, and selected existing clinical global scales are described. In addition, the committee assessed the utility of global scales in clinical trials for antidementia drugs. There was a consensus among the members of the working group on the following: (1) Clinical global scales are interview based; in most cases, they include information obtained from caregivers as well as directly from patients, but they can rely on information from the subject only. (2) Clinicians' global ratings are intended to assess clinically meaningful change based on multidimensional clinical assessment and take into account the clinical heterogeneity of dementia by assessing at least cognition, behavior, and functioning. (3) There are two distinct types of clinical global measures: (a) clinicians' interview-based global severity scales, which generally incorporate classification by stage or severity of illness and (b) clinicians' interview-based global change scales, which incorporate global assessment ratings of clinical change. The committee could not reach a consensus on whether global scales should be required in phase II and phase III clinical trials, or whether other specific assessments such as well-designed activities of daily living, cognition, and behavior measures could, when used in appropriate combinations, replace the global as assessments of clinical meaningfulness.

Activities of Daily Living↗
PubMed1997

[A 10-year-old case with idiopathic oculomotor nerve palsy].

We reported a 10-year-old girl with acquired left oculomotor nerve palsy. Neurologic and radiological examinations failed to reveal the etiology. Following administration of corticosteroid and vitamin B6, diplopia improved within 6 weeks, and mydriasis has been improving over the past 9 months. Idiopathic acquired oculomotor nerve palsy is a very rare condition in childhood, and prognosis of the disease is sometimes good.

Child↗
PubMed1996

Inhibition of lipid peroxidation by diterpenoid from Podocarpus nagi.

A diterpenoid, totarol (1), from Podocarpus nagi was evaluated as an antioxidant. This diterpenoid inhibited autoxidation of linoleic acid. Mitochondrial and microsomal lipid peroxidation induced by Fe(III)-ADP/NADH or Fe(III)-ADP/NADPH were also inhibited. Nagilactone E (2), a norditerpene lactone isolated from the same source, had no antioxidative activity. Furthermore, totarol protected red cells against oxidative hemolysis. This diterpene was shown to be effective in protecting biological systems against oxidative stresses.

Abietanes↗
PubMed1996

Inhibition of aldose reductase by maesanin and related p-benzoquinone derivatives and effects on other enzymes.

A naturally occurring p-benzoquinone derivative, maesanin, inhibited porcine lens aldose reductase. Systematic investigation of related p-benzoquinone derivatives revealed that 2,5-dihydroxy-p-benzoquinone was a potent inhibitor of aldose reductase and aldehyde reductase but had no effect on NADH oxidase. Kinetic analysis showed this p-benzoquinone exhibited uncompetitive inhibition against DL-glyceraldehyde and noncompetitive inhibition against NADPH.

Aldehyde Reductase↗
PubMed1996

Schwannoma of the posterior pharyngeal wall: a case report.

Schwannoma arising in the posterior pharyngeal wall is rare. We report on a 60-year-old man who complained of discomfort in his pharynx, from whom a tumour was excised via an intraoral approach. No recurrence was seen after an 11-year follow-up. The nerve origin of the tumour is most likely to be the peripharyngeal plexus. This is the third such case reported.

Follow-Up Studies↗
PubMed1996

Mode of antibacterial action of totarol, a diterpene from Podocarpus nagi.

The antimicrobial mechanism of totarol was studied using Pseudomonas aeruginosa IFO 3080. This diterpene inhibited oxygen consumption and respiratory-driven proton translocation in whole cells, and oxidation of NADH in membrane preparation. NADH-cytochrome c reductase was inhibited by totarol while cytochrome c oxidase was not. NADH-DPIP reductase and NADH-CoQ reductase were also inhibited. The site of respiratory inhibition of totarol was thought to be near CoQ in the bacterial electron transport chain.

Abietanes↗
PubMed1996

Antiperoxidative components in Thymus vulgaris.

A biphenyl compound, 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (1), and a flavonoid, eriodicytol (2), were isolated as antioxidative components from the leaves of Thymus vulgaris by bioassay-directed fractionation. These compounds inhibited superoxide anion production in the xanthine/xanthine oxidase system. Mitochondrial and microsomal lipid peroxidation induced by Fe(III)-ADP/NADH or Fe(III)-ADP/NADPH were also inhibited by these compounds. Compound 1 is an extremely potent antioxidant; complete inhibition was observed at 1 microM against both microsomal and mitochondrial peroxidation. Furthermore, compound 1 protected red cells against oxidative hemolysis. These phenolic compounds were shown to be effective to protect biological systems against various oxidative stresses.

Animals↗
PubMed1996

Antifungal activity from Alpinia galanga and the competition for incorporation of unsaturated fatty acids in cell growth.

An antimicrobial diterpene was isolated from Alpinia galanga in the screening for potentiators of phytochemical antibiotic action. The structure was elucidated by spectral data and identified as (E)-8 beta, 17-epoxylabd-12-ene-15, 16-dial (1). Diterpene 1 synergistically enhanced the antifungal activity of quercetin and chalcone against Candida albicans. Antifungal activity of 1 was reversed by unsaturated fatty acids. Protoplasts of C. albicans were lysed by 1. These results suggest that antifungal activity of 1 is due to a change of membrane permeability arising from membrane lipid alternation.

Antifungal Agents↗