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Biomedical subjects

M Doi

Publications and source records attributed to M Doi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Two cases of right ventricular ischemic injury due to massive pulmonary embolism.

In general, massive pulmonary embolism induces severe right ventricular overload, but pathological changes in the right ventricle due to pulmonary embolism is rarely seen. In this report, we describe two autopsy cases of massive pulmonary embolism without pre-existing cardiopulmonary disease. Both cases were accompanied by myocarditis-like changes in the right ventricle and infiltration of a number of polymorphonuclear neutrophils and mononuclear cells into the dilated right ventricular wall. Transmural or subendocardial coagulation necrosis was not apparent. Almost all of the mononuclear cells were immunohistochemically revealed to be CD68-positive macrophages. We speculated that these findings resulted from ischemia due to massive pulmonary embolism.

Accidents, Traffic↗
PubMed2001

Dinuclear calcium complex with weakly NH...O hydrogen-bonded sulfonate ligands.

The novel intramolecularly NH...O hydrogen-bonded Ca(II)-aryl sulfonate complex, [Ca2(SO3-2-t-BuCONHC6H4)2(H2O)4]n(2-t-BuCONHC6H4SO3)2n (1), sulfonate anion, (HNEt3)(SO3-2-t-BuCONHC6H4) (2a), (PPh4)(SO3-2-t-BuCONHC6H4) (2b), (n-Bu4N)(SO3-2-t-BuCONHC6H4) (2c), and sulfonic acid, 2-t-BuCONHC6H4SO3H (3), were synthesized. The structures of 1, 2a, and 2b depict the presence of the formation of NH...O hydrogen bonds between the amide NH and S-O oxygen for a series of compounds as determined by IR and 1H NMR analyses both in the solid state and in the solution state. Thus, the NH...O hydrogen bonds with neutral amide groups are available for investigation of the electronic state of the O- anion. The combined data from the IR and 1H NMR spectra indicate that the sulfonic acid, sulfonate anion, and Ca(II) complex have a substantially weak intramolecular NH...O hydrogen bond between the SO3 oxygen and amide NH. In the detailed comparison with the intense NH...O hydrogen bonds for the carboxylate, weak NH...O hydrogen bonds for sulfonate is due to the strong conjugation of the SO3- group with the lower nucleophilicity.

Journal Article↗
PubMed2001

Effects of amino acids and chirality for molecular folding of desoxazoline-ascidiacyclamide derivatives: X-ray crystal structures of four cyclic octapeptides including unusual amino acids, cyclo(-Ile-aThr-D-Val-Thz-)(2), cyclo(-Ala-aThr-D-Val-Thz-Ile-aThr-D-Val-Thz-), cyclo(-Val-aThr-D-Val-Thz-Ile-aThr-D-Val-Thz-), and cyclo(-Ile-aThr-Val-Thz-Ile-aThr-D-Val-Thz-).

Desoxazoline derivative of ascidiacyclamide (1), cyclo(-L-Ile-L-allo-threonine-D-Val-thiazole-)(2), was modified to disturb the C(2)-symmetry. An Ile(1) residue of 1 was replaced for Ala (2) or Val (3), and the D-Val(3) residue was replaced for Val (4). The crystal structures of 1-4 were analyzed by x-ray diffraction methods. The molecules of all compounds were folded and this type of structure was not observed in x-ray structures of ascidiacyclamide derivatives so far except for patellamide D. The folding patterns of 1-4 were similar to each other and resembled that of patellamide. The asymmetric modifications at position 1 caused the conformational changes at local area, and these were related with the peptide-peptide and peptide-solvent interactions. Despite the diverse backbone conformation by the epimeric modification at position 3, the entire molecule of 4 was folded. These results mean that (1) the desoxazoline-ascidiacyclamides favored the folded structures and (2) the modifications of the side chain size at position 1 and the chirality at position 3 brought the local conformational changes to derivatives, suggesting that (3) the lack of the oxazoline block leads to conformational flexibility of 1-4, which accepts the conformational change with no drastic change on the entire structure.

Amino Acids↗
PubMed2001

Brain PET and technetium-99m-ECD SPECT imaging in Lhermitte-Duclos disease.

Two patients with Lhermitte-Duclos disease were evaluated by brain positron emission tomography (PET) and technetium-99m-ethyl cysteinate dimer (99mTc-ECD) single-photon emission computed tomography (SPECT). In the lesions in both patients, hyperperfusion was detected on cerebral blood flow images obtained by PET, and hyperactivity by standard 99mTc-ECD SPECT. Dynamic 99mTc-ECD SPECT images demonstrated a plateau of activity in each lesion. These findings suggest that lesions in Lhermitte-Duclos disease have a retention mechanism for 99mTc-ECD equivalent to that of normal neural tissue.

Adolescent↗
PubMed2001

Combination of early and delayed SPET imaging using technetium-99m ethyl cysteinate dimer immediately after local intra-arterial thrombolysis.

The aim of this study was to investigate the prognostic utility of post-treatment technetium-99m ethyl cysteinate dimer (99mTc-ECD) single-photon emission tomography (SPET) for predicting ischemic tissue outcome in cases involving embolic middle cerebral artery occlusion treated with local intra-arterial thrombolysis. We examined twenty-five patients with a moderately ischemic area determined using pretreatment technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) SPET, and with complete recanalization within 6 h. Post-treatment 99mTc-ECD SPET studies, consisting of scanning for 0.5-6.5 min (early scan) and 15-21 min (delayed scan) after tracer injection, were performed immediately after thrombolysis. The extent of the affected area outlined on pretreatment 99mTc-HMPAO SPET was used for the post-treatment early and delayed 99mTc-ECD SPET images, and the AR/CE ratio (ratio of affected regional activity to cerebellar activity) was calculated. The washout index of 99mTc-ECD in the affected area was also calculated by dividing the difference between the AR/CE ratio in the early and delayed images by the AR/CE ratio in the early image. Twelve patients without infarction or with small subcortical/basal ganglial infarction, ten with medium or large cortical infarction, and three with hemorrhage were identified by follow-up computed tomography. Although the AR/CE ratio in post-treatment early 99mTc-ECD SPET images was significantly higher in the hemorrhagic group than in the cortical infarction group, this value did not differentiate the reversible ischemia group from either the cortical infarction or the hemorrhagic group. The AR/CE ratio in post-treatment delayed 99mTc-ECD SPET images statistically differentiated the reversible ischemia group from both the cortical infarction and the hemorrhagic group. However, the difference between the cortical infarction and hemorrhagic groups was not statistically significant. The washout index of 99mTc-ECD statistically differentiated all three groups. This study demonstrated that a combination of early and delayed 99mTc-ECD SPET imaging performed immediately after thrombolysis predicts ischemic tissue outcome.

Adult↗
PubMed2001

Intrathecal administration of nicardipine hydrochloride to prevent vasospasm in patients with subarachnoid hemorrhage.

OBJECT: To evaluate the prophylactic effect of repeated intrathecal administration of nicardipine associated with hypertensive hypervolemic hemodilution therapy (triple H) and sodium correction, we analyzed a consecutive series of 177 patients with subarachnoid hemorrhage. METHODS: All patients received aneurysmal clipping and placement of cisternal drainage within 48 hours of the onset. Intrathecal administration of 4 mg of nicardipine was performed every 12 h. Nicardipine concentrations in the cerebrospinal fluid (CSF) and blood before and after its administration were analyzed. Angiographic vasospasm (aVS), symptomatic VS (sVS), and clinical outcome 6 months after onset were also evaluated. RESULTS: Nicardipine concentration in CSF on day 9 was 231.44 +/- 51.51 ng/ml (mean +/- SD), and that of blood was 21.05 +/- 15.57 ng/ml. Twenty patients (11.3%) showed aVS, and ten of those (5.7%) showed sVS (six were transient and four were permanent). Those with good outcome (assessed as good recovery and moderately disabled) 6 months after onset were 89.2% of the total. The number of patients requiring a shunt operation was 33 of 177 (18.6%), and 11 patients presented intracranial infection. CONCLUSIONS: These results suggest that our strategy may well prevent VS. However, hydrocephalus and infection may be serious disadvantages that should be resolved.

Adolescent↗
PubMed2001

Cerebral blood flow imaging in arteriovenous malformation complicated by normal perfusion pressure breakthrough.

BACKGROUND: A patient with normal perfusion pressure breakthrough (NPPB) after surgical removal of an arteriovenous malformation (AVM) was evaluated using single photon emission computed tomography cerebral blood flow (CBF) imaging. CASE DESCRIPTION: A 48-year-old man suffered consciousness disturbance because of an intraventricular hemorrhage and underwent ventricular drainage. Cerebral angiography showed a medium-sized AVM in the left parietal lobe. Three months after the ictus, a left parietal craniotomy was performed and total removal of the AVM was achieved. A brain region adjacent to the AVM with preoperative decreased vasoreactivity to acetazolamide showed marked hyperperfusion after AVM excision. Hemorrhage subsequently occurred in this area. CONCLUSION: CBF mapping seems to offer a noninvasive method for the preoperative identification of AVM patients at risk for NPPB, and to allow for early postoperative diagnosis of NPPB.

Blood Flow Velocity↗
PubMed2001

Revised structures for senegalensin and euchrenone b(10).

Two prenylated isoflavones (1 and 2) with a hydroxyisopropyldihydrofuran moiety have been isolated from the wood of Erythrina suberosa var. glabrescence. The structure of compound 1 was in agreement with that of the previously reported senegalensin, isolated from the stem bark of Erythrina senegalensis. The structure of senegalensin was revised from structure 2 to structure 1 by spectroscopic means. Compound 2, the regioisomer of 1, was confirmed as euchrenone b(10) by comparison with the spectral data of the reported euchrenone b(10), isolated from the roots of Euchresta horsfieldii. The structure of 2 was established by 2D NMR spectroscopic analysis and by the X-ray crystallographic analysis of its p-bromobenzoyl derivative (2b).

Chromatography, Gel↗
PubMed2001

HET0016, a potent and selective inhibitor of 20-HETE synthesizing enzyme.

The present study examined the inhibitory effects of N-hydroxy-N'-(4-butyl-2-methylphenyl)-formamidine (HET0016) on the renal metabolism of arachidonic acid by cytochrome P450 (CYP) enzymes. HET0016 exhibited a high degree of selectivity in inhibiting the formation of 20-hydroxy-5,8,11,14-eicosatetraenoic acid (20-HETE) in rat renal microsomes. The IC(50) value averaged 35+/-4 nM, whereas the IC(50) value for inhibition of the formation of epoxyeicosatrienoic acids by HET0016 averaged 2800+/-300 nM. In human renal microsomes, HET0016 potently inhibited the formation of 20-HETE with an IC(50) value of 8.9+/-2.7 nM. Higher concentrations of HET0016 also inhibited the CYP2C9, CYP2D6 and CYP3A4-catalysed substrates oxidation with IC(50) values of 3300, 83,900 and 71,000 nM. The IC(50) value for HET0016 on cyclo-oxygenase activity was 2300 nM. These results indicate that HET0016 is a potent and selective inhibitor of CYP enzymes responsible for the formation of 20-HETE in man and rat.

Amidines↗
PubMed2001

Butenafine hydrochloride (Mentax) cream for the treatment of hyperkeratotic type tinea pedis and its transfer into the horny layer, with or without concomitant application of 20% urea ointment (Keratinamin).

Forty-five patients were divided into two groups: group I, 23 patients, treated with butenafine hydrochloride (Mentax) cream alone, and group II, 22 patients, treated with butenafine hydrochloride and 20% urea ointment (Keratinamin) to evaluate the usefulness of the treatments. We also measured the transfer of these drugs to the horny layer in some patients. The clinical improvement rate of dermatological symptoms (marked improvement + improvement) was 91.3% in group I, 100% in group II, with therapeutic effects evident earlier in group II than in group I. The mycological eradication rate was found to be 47.4% in group I, 50.0% in group II after 4 weeks of treatment, and 81.8 and 87.5% at 12 weeks thereaftcr. respectively, with no adverse reactions found. The clinical utility rate (markedly useful + useful) was 91.3% in group I and 86.4% in group II. These results demonstrate that application of butenafine hydrochloride alone was extremely effective for the treatment of hyperkeratotic-type tinea pedis and that combination application with urea ointment resulted in an earlier improvement of dermatological symptoms. The concentration of butenafine in the horny layer from healthy volunteers reached a steady state in both groups I and II at 2 weeks after the application, with a lower concentration found in group II (about 70 ng mg(-1)) than in group I (about 100 ng,mg(-1)). Although some variations in concentration were found in case by case, patients in whom the treatment was determined to be 'markedly effective and effective' showed the increase in concentration of the drug in the lesional horny layer to be directly proportional to the number of days of treatment, with a lower concentration found in group II than in group I. This trend was also seen in healthy volunteers.

Administration, Topical↗
PubMed2001

Chlorophyll degradation in a Chlamydomonas reinhardtii mutant: an accumulation of pyropheophorbide a by anaerobiosis.

Chlorophyll degradation was investigated in cells of a chlorophyll b-less mutant of Chlamydomonas reinhardtii under aerobic and anaerobic conditions. During degradation of chlorophyll under anaerobic conditions, chlorophyll catabolite P535, an open-tetrapyrrole, was not excreted, but pyropheophorbide a was accumulated as the end product with a transient accumulation of chlorophyllide a and pheophorbide a in cells, in contrast to the breakdown under aerobic conditions. It is likely that in the absence of oxygen, degradation of chlorophyll a proceeds to pyropheophorbide a by three consecutive reactions, dephytylation, metal-releasing and demethoxycarbonylation, and then stops due to a limitation of the oxygen that the monooxygenase reaction requires for bilin formation. A novel enzyme catalyzing demethoxycarbonylation of pheophorbide a was partially purified. The enzyme activity increased dependent on the age of cells, and its increase was completely suppressed by cycloheximide. Production of P535 was also dependent on cytoplasmic protein synthesis.

Anaerobiosis↗
PubMed2001

Auditory evoked potential index predicts the depth of sedation and movement in response to skin incision during sevoflurane anesthesia.

BACKGROUND: The auditory evoked potential (AEP) index, which is a single numerical parameter derived from the AEP in real time and which describes the underlying morphology of the AEP, has been studied as a monitor of anesthetic depth. The current study was designed to evaluate the accuracy of AEPindex for predicting depth of sedation and anesthesia during sevoflurane anesthesia. METHODS: In the first phase of the study, a single end-tidal sevoflurane concentration ranging from 0.5 to 0.9% was assigned randomly and administered to each of 50 patients. The AEPindex and the Bispectral Index (BIS) were obtained simultaneously. Sedation was assessed using the responsiveness portion of the observer's assessment of alertness-sedation scale. In the second phase of the study, 10 additional patients were included, and the 60 patients who were scheduled to have skin incisions were observed for movement in response to skin incision at the end-tidal sevoflurane concentrations between 1.6 and 2.6%. The relation among AEPindex, BIS, sevoflurane concentration, sedation score, and movement or absence of movement after skin incision was determined. Prediction probability values for AEPindex, BIS, and sevoflurane concentration to predict depth of sedation and anesthesia were also calculated. RESULTS: The AEPindex, BIS, and sevoflurane concentration correlated closely with the sedation score. The prediction probability values for AEPindex, BIS, and sevoflurane concentration for sedation score were 0.820, 0.805, and 0.870, respectively, indicating a high predictive performance for depth of sedation. AEPindex and sevoflurane concentration successfully predicted movement after skin (prediction probability = 0.910 and 0.857, respectively), whereas BIS could not (prediction probability = 0.537). CONCLUSIONS: Auditory evoked potential index can be a guide to the depth of sedation and movement in response to skin incision during sevoflurane anesthesia.

Acoustic Stimulation↗
PubMed2001

Lifetime risk of lung cancer due to radon exposure projected to Japanese and Swedish populations.

Lifetime risk projections depend greatly on both background lung cancer rates and the selection of the risk model. Since background lung cancer rates differ from subject populations and the time, etiological risk of lifetime lung cancer mortality per unit radon exposure in WLM should be estimated for each subject population and the time of interest. To answer quantitatively how much are the differences among the projected risks for different populations, the Swedish case-control-study-based risk projection model was applied to the Japanese and Swedish populations from 1962 to 1997 as subject populations because of their distinct trends of lung cancer rates. To compare the results with the reference population and authorized risk projection models, U.S. population 1997 and the two risk projection models in BEIR VI report were applied, respectively. Lifetime risk of lung cancer mortality projected for Japanese, Swedish, and U.S. populations in 1997 per radon progeny exposure were estimated to range from 1.50 (0.40-3.19) x 10(-4) WLM(-1) to 9.86 (2.62-20.9) x 10(-4) WLM(-1), which could be compared to the detriment associated with a unit effective dose. Conclusive dose conversion coefficients in this study ranged from 2.05 (0.55-4.37) to 13.5 (3.59-28.6) mSv WLM(-1), and within this range the discrepancy between dosimetric and epidemiological approaches was included.

Environmental Exposure↗
PubMed2001

Relation of QT-interval variability to ventricular arrhythmias during percutaneous transluminal coronary angioplasty.

The present study investigated the role of the dispersion of QT interval in percutaneous transluminal coronary angioplasty (PTCA)-induced ventricular tachyarrhythmias. Patients with effort angina without a previous myocardial infarction (n = 22), who had single-vessel disease of the anterior descending coronary artery (LAD), underwent PTCA if the coronary lesion was 75% or more stenosed in segment 6 or 7 of the LAD. The standard 12-lead ECG was continuously recorded during the procedure. Averaged QTc and QTac intervals, where QTac was the interval from the beginning of QRS complex to the nadir of T wave corrected by Bazett's formula, did not change significantly during PTCA. Of the 22 patients, 7 showed ventricular arrhythmias during PTCA. The maximum difference (deltaQTc) and the standard deviation (QTcSD) of the corrected QT interval in the standard 12-lead ECG increased significantly during PTCA in the 7 patients with ventricular arrhythmias, whereas they decrreased in the 15 patients without ventricular arrhythmias. deltaQTac and QTacSD were not affected by PTCA regardless of ventricular arrhythmias, which shows that the increases in the variation of the ventricular repolarization process play a role in PTCA-induced ventricular arrhythmias.

Aged↗
PubMed2001

Changes of pyridine nucleotide levels during adipocyte differentiation of mouse 3T3-L1 cells.

The levels of NAD and NADP were measured in 3T3-L1 cells during a differentiation from preadipocytes to adipocytes. The cells were grown in the ordinary medium and differentiated in the medium by adding dexamethasone, 1-methyl-3-isobutylxanthine, and insulin for 2 days, and then they were grown in the medium by adding only insulin for another 8 days to accumulate fat. The levels of cellular NAD and NADP increased abruptly with days after differentiation, and the levels of NAD and NADP reached maximum at day 7, and at day 10 the values were decreased compared with the maximum values. These results suggest that expression of the pyridine nucleotide biosynthesis genes is induced in the differentiation process.

1-Methyl-3-isobutylxanthine↗
PubMed2001

Two cases of severe bronchopneumonia due to influenza A (H3N2) virus: detection of influenza virus gene using reverse transcription polymerase chain reaction.

We report two cases of severe bronchopneumonia due to influenza A (H3N2) virus. The severity of the disease necessitated initiation of empiric therapy based on the present illness and clinical data on admission. Both patients were improved by artificial ventilation with positive end-expiratory pressures and administration of broad spectrum antibiotics and corticosteroids before confirming the diagnosis of viral bronchopneumonia using viral culture and serological tests. Within 24 hours, influenza A (H3N2) virus was identified by amplification of the pathogen genes by reverse transcription polymerase chain reaction (RT-PCR) using the stored bronchoalveolar lavage (BAL) fluids of both cases. This suggests that a combination of detection methods of pathogens using RT-PCR and BAL fluid will facilitate determination of rational treatment aimed at influenza A virus.

Aged↗