Biomedical subjects

K Aoki

Publications and source records attributed to K Aoki.

At least 163 records · Page 9Linked to original sources

PubMed2000

CT scans essential after posttraumatic loss of consciousness.

The frequency of "talk and deteriorate" in the emergency department (ED), subsequent deterioration of patients with seemingly "mild" head injury at the time of presentation, is summarized. Among the 1,073 patients with minor head injury treated in the last 5 years, five patients (0.5%) deteriorated in the ED. All of the five patients had experienced transient loss of consciousness (LOC) before presentation. Deterioration had occurred during treatment of trivial associated injuries in four-fifths of the cases. Computed tomography (CT) scans revealed four acute epidural hematomas and one cerebellar contusion. Retrospectively, immediate brain CT shortly after their arrival may have revealed the presence of traumatic intracranial hematomas before deterioration. Although routine use of CT scans in patients with mild head injury has been controversial, the authors conclude that CT scans should be taken if patients have experienced transient LOC to prevent or reduce the occurrence of deterioration in ED.

Adult↗

PubMed2000

Oxythiamine hexafluorophosphate monohydrate, a thiamine antagonist with the same conformation as thiamine.

In the title compound, 3-[(3,4-dihydro-2-methyl-4-oxopyrimidin-5-yl) methyl]-5-(2-hydroxyethyl)-4-methylthiazolium hexafluorophosphate monohydrate,C(12)H(16)N(3)O(2)S(+).PF(6)(-).H(2)O, oxythiamine is a monovalent cation with a neutral oxopyrimidine ring. The molecule assumes the F conformation, which is a common form for thiamine but which is substantially different from the unusual V conformation found in the chloride and hydrochloride salts of oxythiamine. The anion-bridging interaction, C-H...anion...pyrimidine, is emphasized as being important for stabilization of the F conformation.

Crystallography, X-Ray↗

PubMed2000

Participation of CYP2A in cocaine-induced hepatotoxicity in female mice.

Female ICR mice were treated with cocaine either alone or in combination with one of several cytochrome P450 (CYP) inducers, i.e. phenobarbital, beta-ionone, dexamethasone and beta-naphthoflavone. Cocaine-induced hepatotoxicity was first observed by pretreatment with phenobarbital, beta-ionone or dexamethasone in accordance with significant elevation of cocaine N-demethylation, the first step of cocaine bioactivation. The hepatic lesions occured in the periportal region (zone 1) by phenobarbital and beta-ionone and in the perivenular region (zone 3) by dexamethasone. The activities of the enzyme specific for CYP isozyme were determined to elucidate the effects of pretreatment with CYP inducers. Beta-naphthoflavone induced CYP1A and 2B but had no effects on hepatotoxicity by cocaine. On the other hand, beta-ionone enhanced hepatotoxicity without induction of CYP3A. Activities of cocaine N-demethylase correlated well with CYP2A (r=0.83) and CYP2B (r=0.81). Cocaine N-demethylation was inhibited particularly by addition of the CYP2A specific inhibitor, 8-methoxypsoralen. Moreover, pretreatment with 8-methoxypsoralen produced a marked inhibition of the hepatotoxicity induced by cocaine in phenobarbital-treated mice. These results suggest that cocaine-induced hepatotoxicity in female mice was mediated in part by CYP2A, participating in cocaine N-demethylation.

Alanine Transaminase↗

PubMed2000

Successful uterine steroid therapy in a case with a history of ten miscarriages.

A woman experienced ten unexplained first trimester miscarriages. Uterine steroid therapy was performed just before her 11th pregnancy. Prednisolone was inserted into the uteral cavity before ovulation and her 11th pregnancy resulted in success. Our experience in this case confirms the potential usefulness of this treatment for patients with unexplained recurrent miscarriages.

Abortion, Habitual↗

PubMed2000

Adverse influence of numbers of previous miscarriages on results of paternal lymphocyte immunization in patients with recurrent spontaneous abortions.

PROBLEM: To determine whether an increase in the number of previous miscarriages in recurrent spontaneous abortion patients is a risk factor in subsequent pregnancies with paternal lymphocyte immunotherapy. METHOD OF STUDY: Live birth rates with reference to previous abortion numbers in recurrent spontaneous abortion patients were statistically compared between paternal lymphocyte immunotherapy and control groups, the latter retrospectively researched using historical data before 1981 in our clinic. RESULTS: The overall live birth rate was 73% (169/232) in the immunotherapy group, and 48% (47/97) in controls (P <0.05). According to previous abortion numbers, the rates were 77% (114/148) versus 55% (36/65) (P < 0.05) for three previous abortions, 70% (40/57) versus 38% (8/21) (P < 0.05) for four and 56% (15/27) versus 27% (3/11) (not significant) for five, in the study and control groups, respectively. CONCLUSIONS: The results confirm the efficacy of paternal lymphocyte immunotherapy, but demonstrate that the success rate deteriorates with the number of previous miscarriages.

Abortion, Habitual↗

PubMed2000

Psychosocial factors regulating natural-killer cell activity in recurrent spontaneous abortions.

PROBLEM: The preconceptional natural-killer cell (NK) activity predicts subsequent miscarriage among women with unexplained recurrent spontaneous abortion (RSA). Psycho-neuro-immuno-endocrine network has recently been proposed as a mechanism for abortions. We therefore examined which psychosocial factors influenced the NK activity among women with RSA. METHOD OF STUDY: We measured the preconceptional NK activity of 61 women with a history two consecutive unexplained first-trimester miscarriages and no live births. We also administered semi-structured interviews and a battery of self-report questionnaires to assess their social support, personality, self-esteem and psychiatric symptoms. RESULTS: The preconceptional NK activity was negatively correlated with the women's neuroticism personality trait (r= -0.32, P = 0.01) and current depressive symptoms (r = -0.26, P= 0.05), and positively correlated with their self-esteem (r = 0.34, P = 0.01). CONCLUSIONS: In addition to several substances such as transforming-growth-factor beta and granulocyte-macrophase colony-stimulating factor, we found that low neuroticism, low depression scale score and high self-esteem contributed to high NK activity among women with RSA.

Abortion, Habitual↗

PubMed2000

Clinical and epidemiological features of acute follicular conjunctivitis with special reference to that caused by herpes simplex virus type 1.

BACKGROUND/AIMS: It is reported by the national surveillance of ocular infectious diseases in Japan that 4.3% of cases of epidemic keratoconjunctivitis (EKC) diagnosed clinically were caused by herpes simplex virus (HSV). Clinical and virological studies of patients with HSV conjunctivitis were carried out. METHODS: The study population consisted of 478 patients with acute follicular conjunctivitis. Virological analysis was carried out for adenovirus (Ad) and HSV by the cell culture method and fluorescein antibody (FA) method. Polymerase chain reaction for Chlamydia trachomatis was also carried out. RESULTS: From 23 patients, HSV type 1 was isolated but Ad or C trachomatis was not isolated. 87% of cases were unilateral. Most cases showed clinical resolution within 9 days. Early corneal lesions and preauricular lymphadenopathy were less frequent in HSV conjunctivitis than in adenoviral conjunctivitis, especially that due to subgenus D. No case showed a positive result for HSV by the FA method using conjunctival swabs; however, the FA test was positive in all strains isolated by cell culture. CONCLUSIONS: These results indicate that it is difficult clinically to differentiate HSV conjunctivitis from adenoviral conjunctivitis in the acute stage, since the clinical features of adenoviral conjunctivitis are similar to those of HSV conjunctivitis. A biological difference may exist between HSV strains causing keratitis and conjunctivitis.

Acute Disease↗

PubMed2000

Effects of exercise intensity on the sweating response to a sustained static exercise.

To investigate how the sweating response to a sustained handgrip exercise depends on changes in the exercise intensity, the sweating response to exercise was measured in eight healthy male subjects. Each subject lay in the supine position in a climatic chamber (35 degrees C and 50% relative humidity) for approximately 60 min. This exposure caused sudomotor activation by increasing skin temperature without a marked change in internal temperature. After this period, each subject performed isometric handgrip exercise [15, 30, 45, and 60% maximal voluntary contraction (MVC)] for 60 s. Although esophageal and mean skin temperatures did not change with a rise in exercise intensity and were similar at all exercise intensities, the sweating rate (SR) on the forearm increased significantly (P < 0.05) from baseline (0.094 +/- 0.021 mg. cm(-2). min(-1) at 30% MVC, 0.102 +/- 0.022 mg. cm(-2). min(-1) at 45% MVC, 0.059 +/- 0.009 mg. cm(-2). min(-1) at 60% MVC) in parallel with exercise intensity above exercise intensity at 30% MVC (0.121 +/- 0.023 mg. cm(-2). min(-1) at 30% MVC, 0.242 +/- 0.051 mg. cm(-2). min(-1) at 45% MVC, 0.290 +/- 0.056 mg. cm(-2). min(-1) at 60% MVC). Above 45% MVC, SR on the palm increased significantly from baseline (P < 0.05). Although SR on the forearm and palm tended to increase with a rise in exercise intensity, there was a difference in the time courses of SR between sites. SR on the palm showed a plateau after abrupt increase, whereas SR on the forearm increased progressively during exercise. These results suggest that the increase in SR with the increase in sustained handgrip exercise intensity is due to nonthermal factors and that the magnitude of these factors during the exercise may be responsible for the magnitude of SR.

Adult↗

PubMed2000

Mechanism of ATP-induced [Ca(2+)](i) mobilization in rat basilar smooth muscle cells.

BACKGROUND AND PURPOSE: We have previously reported that extracellular ATP activates P(2u) receptors and increases intracellular free Ca(2+) ([Ca(2+)](i)) by G protein/phospholipase C/inositol 1,4,5-triphosphate pathways in cerebral artery smooth muscle cells. However, the possible contribution of other signaling pathways remains unclear. This study was undertaken to investigate the role of protein tyrosine kinase (PTK) and mitogen-activated protein kinase (MAPK) in mediating ATP-induced Ca(2+) mobilization in rat basilar artery smooth muscle cells (RBASMCs). METHODS: RBASMCs were freshly isolated, and [Ca(2+)](i) was monitored by fura 2 microfluorimetry. MAPK phosphorylation was studied by the Western blot technique. RESULTS: ATP produced a biphasic [Ca(2+)](i) response, which consists of releasing Ca(2+) from internal stores and influx from extracellular space. PTK inhibitors tyrphostin 51 and genistein inhibited [Ca(2+)](i) response to ATP. Tyrphostin A1, an inactive analogue of tyrphostins, failed to reduce the ATP-induced response. MAPK kinase inhibitor PD98059, but not U0126, reduced the ATP-induced [Ca(2+)](i) response. Phosphatidylinositol 3-kinase (PI3-K) tyrosine kinase inhibitor wortmannin, but not janus tyrosine kinase (JAK2) inhibitor AG490, partially inhibited the [Ca(2+)](i) response induced by ATP. In addition, ATP enhanced MAPK phosphorylation in a concentration- and time-dependent manner, and genistein, tyrphostin 51, PD98059, and U0126 inhibited MAPK phosphorylation. CONCLUSIONS: Extracellular ATP produced [Ca(2+)](i) elevation and MAPK phosphorylation in RBASMCs, and the effect was regulated by PTK. The role of MAPK in ATP-induced [Ca(2+)](i) elevation is not clear. PI3-K tyrosine kinase and JAK2 tyrosine kinase may not play an important role in the ATP-induced [Ca(2+)](i) response in RBASMCs.

Adenosine Triphosphate↗

PubMed2000

Mastoid pneumatization of the patulous eustachian tube.

The pathophysiology of the patulous eustachian tube (PET) remains unclear. The degree of mastoid cell pneumatization is considered an indicator of chronic inflammation of the middle ear. We used the mastoid cell area to investigate the relationship between past chronic inflammation of the middle ear cavity and a PET in 84 patients (20 to 83 years old). The mastoid cell size was calculated from radiographs and analyzed relative to the history of otitis media (OM). The controls were 100 normal ears. The patients' mastoid cell size was significantly suppressed versus that of the controls, in both 31 PET cases with and 53 PET cases without past OM. We surmise the possibility that the PET ears had experienced inflammation even when the patients had no history of OM and the tympanic membrane showed no OM sequelae. This study indicates the existence of some relationship between a history of chronic inflammation of the middle ear cavity and a PET.

Adult↗

PubMed2000

Rate enhancement with high ratio of the monoalkylated product to the dialkylated product in the alkylation of the lithium enolate of 1-tetralone with reactive alkyl halides.

The reactions of the lithium enolate of 1-tetralone with reactive alkyl halides were examined in the absence and in the presence of 3 eq of various ligands for the lithium. It is shown that the rates of the reactions are enhanced greatly in the presence a tetradentate amine (1,1,4,7,10,10-hexamethyltriethylenetetramine), and the ratio of the monoalkylated product to the dialkylated product is increased under shorter reaction times.

Alkylation↗

PubMed2000

Stereoselective reactions. XXXII. Enantioselective deprotonation of 4-tert-butylcyclohexanone by fluorine-containing chiral lithium amides derived from 1-phenylethylamine and 1-(1-naphthyl)ethylamine.

Enantioselective deprotonation of 4-tert-butylcyclohexanone was examined using 1-phenylethylamine- and 1-(1-naphthyl)ethylamine-derived chiral lithium amides having an alkyl or a fluoroalkyl substituent at the amide nitrogen. The lithium amides having a 2,2,2-trifluoroethyl group on the amide nitrogen are easily accessible in both enantiomeric forms, and were found to induce good enantioselectivity in the present reaction.

Amides↗

PubMed2000

Isolated cardiac metastasis from sacral chordoma.

A 64-year-old woman presented with right heart failure caused by a cardiac tumor centered in the free wall of the right ventricle, accompanied by pericardial effusion. A match between the biopsy specimen and tissue removed 4 years earlier resulted in the diagnosis of a cardiac metastasis from a chordoma. Immunohistochemical staining was also useful in establishing the diagnosis. To alleviate the right ventricular outflow obstruction, a palliative operation was planned, resecting the tumor and performing a right ventriculoplasty, which was cancelled due to the extent of infiltration of the tumor, and instead a right atrium to pulmonary artery shunt was attempted using a vascular prosthesis, only to fail due to an inability to maintain blood flow through the prosthesis. Presently there are no definitive treatment options available, and some palliative chemotherapy is being performed. Single cardiac metastases from a chordoma are extremely rare.

Antigens, Neoplasm↗

PubMed2000

Effects of physical training on the recovery of the autonomic nervous activity during exercise after coronary artery bypass grafting: effects of physical training after CABG.

Analysis of heart rate variability (HRV) can identify patients at risk of sudden cardiac death after myocardial infarction. The present study examined the effect of 2 weeks of supervised aerobic exercise training on the recovery of the autonomic nervous activity, exercise capacity, and cardiac output (CO) after coronary artery bypass grafting (CABG). Twenty-eight patients were randomly divided into the training group or the control group and performed exercise tests at 1 week, 3 weeks, 3 months, 6 months and 1 year after CABG. The HRV was measured, and the high-frequency component of HRV was used as an index of parasympathetic nerve activity (PNA); the plasma norepinephrine concentration (NE) was used as an index of sympathetic nervous activity. Cardiac output was also measured. In the training group, peak VO2, peak CO and PNA during exercise had improved at 3 weeks, but there was no improvement in these indices in the control group. NE decreased 1 week after CABG in both groups. These results indicate that physical training soon after CABG improves not only the exercise capacity, but also PNA.

Aged↗

PubMed2000

Impaired heart rate response during incremental exercise in patients with acute myocardial infarction and after coronary artery bypass grafting: evaluation of coefficients with Karvonen's formula.

Heart rate (HR) response during exercise in patients with ischemic heart disease was evaluated, and the appropriateness of Karvonen's method for determining rehabilitation exercise target HR was investigated. The study group comprised 24 patients with acute myocardial infarction (AMI) and 37 patients who had undergone coronary artery bypass grafting (CABG). Cardiopulmonary exercise testing (CPX) was performed with a cycle ergometer and changes in HR (deltaHR)/changes in work rate (deltaWR) and interval changes of the coefficient of Karvonen's formula were evaluated. In the AMI group and the CABG group, deltaHR/deltaWR were significantly lower than those of age-matched control subjects (p<0.01). Karvonen's coefficients ranged from 0.37 to 0.54 when calculated from actual peak HR and 0.21 to 0.32 calculated from the predicted peak HR. An impaired HR response was found in patients with AMI and those who had had CABG up to 6 months previously. Because the Karvonen's coefficient values, which ranged from 0.6 to 0.8, were elevated for these patients, and considering the data from the CPX, increased exercise is recommended for such cases.

Adrenergic beta-Antagonists↗

PubMed2000

[A study on serum carotenoid levels of people with hyperglycemia who were screened among residents living in a rural area of Hokkaido, Japan].

Serum carotenoid levels among residents with hyperglycemia who were screened in a health check-up program for the inhabitants living in a rural area of Hokkaido were compared with those with normal levels. Serum levels of alpha, beta-carotenes and cryptoxanthin were lower among those with high HbA1c newly detected than among those with a normal level, whereas the serum lipid peroxide (TBARS) level was higher in the former than in the latter for both sexes. Among males who currently smoked and drank alcohol, the intake frequency of carrot or pumpkin was significantly lower for those with high HbA1c than for the others, although no significant differences of serum carotenoid levels were observed. For the diabetes mellitus patients who were consulted in this study, and who have already been under control in the clinic, no significant differences of serum levels of carotenoids, or lipids such as total cholesterol and TBARS were shown compared with other groups. In conclusion, serum carotenoid levels might be a useful indicator of food intake and oxidative stress for the prediabetic condition since newly detected hyperglycemia tends to show lower serum antioxidant levels such as beta-carotene, and higher serum lipid peroxide levels.

Adult↗

PubMed2000

Purification and characterization of a basic amino acid-specific peptidase from seeds of jack bean (Canavalia ensiformis).

A peptidase was purified from seeds of Canavalia ensiformis by extraction with water, ammonium sulfate precipitation, and successive chromatographies on DEAE-Toyopearl 650M, butyl-Toyopearl 650M, and G-3000 SW columns. The enzyme has an apparent molecular weight of 41,000. Activity is maximal at pH 9 and 60 degrees C. The enzyme hydrolyzed synthetic substrates at Arg-X and Lys-X bonds more rapidly than bovine trypsin did, and did not cleave protein or ester substrates. The enzyme was inhibited by alkylamines and several serine protease inhibitors such as diisopropylfluorophosphate, chymostatin, leupeptin, and benzamidine. Cysteine protease-, metalloprotease-, and proteinous trypsin inhibitors were ineffective. Inhibition by alkylamines was dependent on length of the alkyl chains. From the substrate specificity and susceptibility to chemicals, the enzyme is a unique peptidase with trypsin-like specificity.

Chromatography, Ion Exchange↗

PubMed2000

Genetic characteristics of cellulose-forming acetic acid bacteria identified phenotypically as Gluconacetobacter xylinus.

Gluconacetobacter xylinus (=Acetobacter xylinum) shows variety in acid formation from sugars and sugar-alcohols. Toyosaki et al. proposed new subspecies of G. xylinus (=Acetobacter xylinum) subsp. sucrofermentans in point of acid formation from sucrose and a homology index of 58.2% with the type strain of G. xylinus subsp. xylinus in DNA-DNA hybridization experiments. We tried DNA-DNA hybridization to clarify relationship between acid formation from sugars and classification of G. xylinus. The G + C contents of G. xylinus showed 60.1-62.4 mol% with a range of 2.3 mol%. When type strains of G. xylinus subsp. xylinus, G. xylinus subsp. sucrofermentans, and IFO 3288 forming acid from sucrose, were used as probes, the DNAs from three strains showed 67-100%, 64-89%, and 60-100% similarity to those from sixteen strains including bacteria that form acid from sucrose or not. These results show that homology indexes do not reflect differences of acid formation from sucrose. As a results, the species G. xylinus was proved to be genetically homogeneous.

Acetic Acid↗