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Biomedical subjects

N Aikawa

Publications and source records attributed to N Aikawa.

At least 73 records · Page 4Linked to original sources
PubMed1995

Rapid increase in plasma nitrite concentration following intravenous administration of nipradilol.

Nipradilol, a beta-adrenoceptor antagonist with vasodilator activity, has a structure which contains a NO2 group. In anesthetized dogs, the time course of the systemic vasodilation and plasma nitrite (NO2-) concentration was studied following intravenous administration of nipradilol (1 mg/kg). A fall in systemic vascular resistance was observed at 1 min, which was rapidly followed by a significant increase in the plasma NO2- concentration. It is indicated that nipradilol exerts systemic vasodilatation via nitric oxide (NO) release in vivo.

Adrenergic beta-Antagonists↗
PubMed1995

Secondary exposure of medical staff to sarin vapor in the emergency room.

OBJECTIVE: To clarify the risk of secondary exposure of medical staff to sarin vapor in the emergency room, and to warn emergency room staffs of the hazard. DESIGN: Retrospective observational survey. SETTING: Emergency department of a university hospital in a metropolitan area of Japan. PARTICIPANTS: Fifteen doctors treating victims of a terrorist attack with sarin in the Tokyo subways on the day of the attack. MEASUREMENTS AND RESULTS: Of the 15 doctors who worked in the emergency room treating the victims, 13 became simultaneously aware of symptoms during the resuscitation of two victims who were exposed to sarin. Among 11 doctors (73%) who complained of dim vision, the pupils were severely miotic (<2 mm) in 8 (73%). Other symptoms included rhinorrhea in eight (53%), dyspnea or tightness of the chest in four (27%), and cough in two (13%). Atropine sulfate was given to six, and pralidoxime was given to one of these six doctors. To decontaminate the emergency room of sarin vapor, ventilation was facilitated and all belongings of the patients were sealed up. None of the doctors noticed worsening of their symptoms thereafter. CONCLUSIONS: Careful attention to the risks of secondary exposure to toxic gas in the emergency room and prompt decontamination if such exposure should occur are necessary in the case of large-scale disasters caused by sarin.

Adult↗
PubMed1995

Neutrophil-mediated tissue injury and its modulation.

Neutrophils play a key role in the development of the systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS). Since the lungs are the main target in these syndromes, with adult respiratory distress syndrome (ARDS) as the outcome, extensive research has been undertaken to prevent or mitigate ARDS. As evidence of the involvement of neutrophils in ARDS has accumulated, modulation of their function has become a major goal in terms of a therapeutic approach. In this short review, we sought to update our knowledge about neutrophils. Firstly, we summarized the various stimuli which activate neutrophils. Secondly, we described the different mediators, including cytokines, which are released by neutrophils. Lastly, we discussed the possible modulation of their function. Although we cannot assess the clinical usefulness of biochemical substances merely on the basis of their in vitro effects, understanding these mechanisms is fundamental to the success of the new therapeutic approach which is currently under way.

Cytokines↗
PubMed1995

An alternative limb lead system for electrocardiographs in emergency patients.

It is occasionally difficult to record the standard 12-lead electrocardiograph (ECG) in emergency patients. The aim of this study was to evaluate the influence on electrocardiographic wave form recordings of moving the location of electrodes from the standard limb lead position to the trunk. The participants were 10 normal subjects and 20 patients with heart disease. In the new lead system, the limb electrodes were placed on the anterior acromial region and the anterior superior iliac spine using adhesive electrodes. Conventional 12-lead ECGs were recorded by the standard and the new lead system simultaneously in the supine position. Wave form analysis was done by an automatic analysis program. Motion artifacts in the recordings were less in the new lead system. The R wave amplitude of the new lead system increased in leads II, III and aVF, and decreased in leads I and aVL. However, the amplitudes of each wave obtained by standard electrocardiography and the new lead system correlated well (y = 1.008x + 2.038, r = 0.99, n = 2,880). In 99.6% of all wave forms, the differences in amplitudes were within 5% of the values of standard recordings. The average of differences in the ST-segment was 2.6 +/- 11.4 microV. The frontal plane QRS axis obtained by the new lead system showed a vertical shift of 7.8 +/- 8.5 degrees (y = 0.94911x + 10.346, r = 0.98, n = 30). The recording errors produced by the new lead system were within the permissible range of variation. The new lead system is a reasonable alternative for recording ECGs if application of the standard lead is difficult in an emergency.

Adult↗
PubMed1994

[Blood pressure change and syncope during leg phlebography].

Although syncope attacks such as black-out, faint consciousness, and cold sweat are sometimes experienced during leg phlebography, no study of their incidence and mechanism has been reported. We measured blood pressure noninvasively by using a Finapress with ECG monitor during overall examinations (21 cases, 33 limbs; male 8, female 13) following anamnesis. Age, sex, and past history of drug, syncope, leg phlebography, and other diseases were determined. All examinations were done in the upright position. Three cases (14.3%) and four limbs (12.1%) showed syncope attacks during leg phlebography. Syncope occurred after steps taken for the evaluation of venous return in two limbs, during infusion of contrast medium in one, and after infusion in the other. In all cases, the systolic blood pressure measurement during syncope was below 80 mmHg, and the sudden decrease of both systolic blood pressure (-83.0 +/- 22.0 mmHg) and heart rate (-29.5 +/- 5.0/min) suggested vasovagal reaction as a mechanism of syncope. Other causes of syncope including anaphylaxy, hyperventilation syndrome, seizure, and arrhythmia (except for bradycardia) were not found. There were also significant changes in blood pressure and heart rate in the nonsyncope group during leg phlebography that seemed to trigger vasovagal excitation. Premedication, contrast media, and position might be important factors and should be discussed further.

Adult↗
PubMed1994

The effects of dopamine infusion on the postoperative energy expenditure, metabolism, and catecholamine levels of patients after esophagectomy.

Although dopamine is one of the most widely used vasoactive agents, its postoperative thermogenic and metabolic effects have not been studied. In this study, the effects of low-dose dopamine, given at 5 microgram/kg/min, on resting energy expenditure (REE), metabolism, and plasma catecholamine levels were examined in eight postsurgical patients. Dopamine infusion increased REE from 1,839 +/- 171 kcal/day to 2,071 +/- 170 kcal/day, and it decreased to 1,867 +/- 141 kcal/day after cessation of the infusion. Dopamine also increased the plasma levels of glucagon from 109.4 +/- 8.7 pg/ml to 132.5 +/- 8.0 pg/ml, and it decreased to 102.9 +/- 11.1 pg/ml after cessation of the infusion. The plasma levels of dopamine before, during, and after the infusion were 116.1 +/- 18.3, 161.1 +/- 25.6 and 121.4 +/- 17.2 ng/ml, respectively. Insulin and glucose were affected by dopamine, but changes in their plasma levels did not parallel the dopamine levels. Epinephrine and norepinephrine were increased by the infusion of dopamine and continued to increase even after its cessation. The results of this study revealed that low-dose dopamine increased REE in postsurgical patients and that this might be associated with the concomitant increase in plasma glucagon.

Aged↗
PubMed1994

[Bacteria isolated from intraabdominal infection and their susceptibilities to antimicrobial agents].

Bacteria isolated from intraabdominal infections during the period from July 1982 to June 1993 were investigated with regard to their classifications according to a joint research by 9 university hospitals in Japan. The following results were obtained. 1. A total of 971 strains were isolated from 684 out of 597 patients with peritonitis, and 287 strains out of 971 were isolated from postoperative peritonitis. 2. The most predominant organism isolated from patients with acute peritonitis was Escherichia coli (28%), followed by Bacteroides fragilis group (17%), Gram-positive anaerobic cocci (16%), Enterococcus spp. (9%) and Klebsiella spp. (8%). 3. Against E. coli, cefmenoxime, cefuzonam, cefozopran, aztreonam and carumonam showed MIC50 less than 0.05 micrograms/ml. Against B. fragilis group, erthromycin, clindamycin, imipenem, lincomycin and latamoxef showed MIC50 less than 0.78 micrograms/ml. 4. The most predominant organism isolated from patients with postoperative peritonitis was Enterococcus spp. (20%) and followed by Pseudomonas spp. (14%), and Staphylococcus spp. (13%), E. coli (9%), Enterobacter spp. (8%) and Klebsiella spp. (8%). We suggest that cefazolin, cefmetazole, flomoxef, cefmenoxime, cefuzonam, and latamoxef are the first choice agents in empiric therapy for the treatment of acute peritonitis.

Aged↗
PubMed1994

[Year to year changes in isolation frequencies of different bacteria from postoperative infections].

Bacterial species isolated from postoperative infections during the period from July 1982 to June 1993 were studied regarding isolation frequencies of different species in different years in a joint research project involving nine (9) university hospitals in Japan. The obtained results are summarized as follows. (1) Altogether, 1,453 strains were isolated with 153 strains obtained during the most recent one year from July of 1992 through June of 1993. The most numerous source of isolation was postoperative intra-abdominal sepsis. (2) Gram-positive cocci were the most often isolated, among them methicillin-resistant Staphylococcus aureus was isolated in increasing frequencies until June, 1992. (3) In the last one year, Enterococcus spp. was isolated the most from postoperative infections followed by Staphylococcus spp. and Pseudomonas spp. Rates of isolation of anaerobic bacteria were relatively low with annual isolation frequencies ranging 8 to 15 per cent.

Digestive System Diseases↗
PubMed1994

[Intractable bacterial infections in surgical patients].

Although many new antibiotics became available for clinical use, intractable bacterial infections are still major cause of morbidity and mortality in surgical patients. The infections are attributable to multiple factors. Surgical stress such as extensive burns and major surgery results in the depressed host-defense function, which is mediated by cytokine responses. Necrotic tissue, ischemia, hematoma, cholelithiasis, foreign bodies, indwelling catheters, intra-tracheal tubes, and other medical devices are local factors making infection resistant to ordinary chemotherapy. Multi-resistant bacteria such as methicillin resistant Staphylococcus aureus and Pseudomonas, and ampicillin resistant enterococci are the main bacteria causing the infections. 32% of surgical specimens isolated two or more bacteria, making the chemotherapy difficult in clinical setting. Importance of surgical drainage, removal of necrosis and the devices are emphasized.

Aged↗
PubMed1993

Role of 5-hydroxytryptamine in the progression of monocrotaline induced pulmonary hypertension in rats.

OBJECTIVE: The aim was to clarify the role of serotonin (5-hydroxytryptamine, 5-HT) in monocrotaline induced pulmonary hypertension. METHODS: Plasma 5-HT levels, pulmonary capillary platelet count, and vascular responsiveness to 5-HT were evaluated in the model. The effects of the selective 5-HT2 receptor antagonist, DV-7028, on the development of pulmonary hypertension were also investigated. RESULTS: Plasma 5-HT was raised 12 h to 3 d after monocrotaline administration (60 mg.kg-1), coinciding with accumulation of platelets in the pulmonary circulation. Isolated pulmonary arteries showed hyperreactivity to 5-HT at 14 and 21 d after monocrotaline. Administration of DV-7028 (20 mg.kg-1 x d-1) attenuated the increase in pulmonary arterial pressure, right ventricular hypertrophy, and medial thickening of the pulmonary arteries. CONCLUSIONS: The present study suggests that 5-HT released from platelets contributes to the initiation and progression of monocrotaline induced pulmonary hypertension.

Animals↗