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Biomedical subjects

H Sakurai

Publications and source records attributed to H Sakurai.

At least 235 records · Page 13Linked to original sources
PubMed1998

Cross sectional observation of the effects of carbon disulphide on the nervous system, endocrine system, and subjective symptoms in rayon manufacturing workers.

OBJECTIVES: A prospective cohort study was initiated to clarify whether the current level of exposure to carbon disulphide (CS2) is low enough to prevent occurrence of subclinical health impairments or to ameliorate health effects due to past high exposure. This paper describes the effects of exposure to CS2 on the nervous and endocrine systems, and the subjective symptoms in a baseline observation. METHODS: The effects were evaluated of CS2 on the median nerve conduction velocity, neurobehavioural and psychological tests, and subjective symptoms related to solvents in 432 male workers exposed to CS2 and 402 reference workers from 11 rayon factories in Japan. Adjustment was made for potential confounding factors such as age or alcohol drinking. Exposure to CS2 was either dichotomised or categorised into three groups by job type. RESULTS: Reductions were observed in motor (-1.9 m/s) and sensory (-0.91 m/s for orthodromic and -1.1 m/s for antidromic) nerve conduction velocities in the workers exposed to CS2 at the spinning and refining processes. Small but significant increases were found in self rated depression scale score and decrease in digit span (backward) in the workers exposed to CS2. Of 54 subjective symptoms many were increased--namely, heavy feeling in the head, light headedness, fainting after suddenly standing up, tremor, dullness, and increased sensitivity of skin in the extremities, reduced grasping power, reduced sexual desire, and increased rough skin. The endocrinological indicator--the concentration of glycosylated haemoglobin--was also increased in the workers exposed to CS2. CONCLUSIONS: Subclinical effects on the nervous system and on glucose metabolism were found in the workers exposed to CS2. One interpretation is that relatively higher exposure to CS2 in the past may induce these, but the effects are still not entirely ameliorated under the current exposure to CS2. Another possibility is that the current exposure to CS2 may cause these positive findings. A follow up observation is necessary to clarify these questions.

Adult↗
PubMed1998

Effect of reduced bronchial circulation on lung fluid flux after smoke inhalation in sheep.

We determined the effect of reduced bronchial blood flow on lung fluid flux through changes in lung lymph flow, lung wet weight-to-dry weight (wet/dry) ratios, and pulmonary microvascular reflection coefficient (sigma). In the first of two surgical procedures, Merino ewes (n = 21) were surgically prepared for chronic study. Five to seven days later, in a second operation, the bronchial artery of the injection group (n = 7) was ligated, and 4 ml of 70% ethanol were injected into the bronchial artery to cause sclerosis of the airway circulation. In the ligation group (n = 7), only the bronchial artery was ligated. In the sham group (n = 7), the bronchial artery was surgically exposed but left intact without ligation or ethanol injection. One day after these operations the animals received a tracheotomy and 48 breaths of cotton smoke. The value of sigma was determined at two points: 24 h before the second surgical procedure and 24 h after smoke inhalation. Lung lymph flow, blood-gas parameters, and hemodynamic data were measured every 4 h after injury. At the end of investigation, samples of lung were taken for determination of blood-free wet/dry ratio. In the sham group, inhalation injury induced a gradual increase in pulmonary vascular resistance and lung lymph flow, which was associated with deterioration of oxygenation. Reduction of the bronchial blood flow attenuated these pathophysiological changes, and the degree of this attenuation was greater in the injection group than in the ligation group. The value of sigma was significantly higher after smoke inhalation in the injection group compared with the sham group (0.77 +/- 0.04 vs. 0.61 +/- 0.03, means +/- SE) at 24 h. The mean wet/dry ratio value of the injection group animals was 30% less than that of the sham group. Our data show that the bronchial circulation contributes to edema formation in the lung occurring after acute lung injury with smoke inhalation.

Animals↗
PubMed1998

Central bisegmentectomy of the liver plus caudate lobectomy for carcinoma of the gallbladder.

Central bisegmentectomy of the liver is recommended as a radical surgical procedure for patients with liver-bed gallbladder carcinoma, which tends to directly invade the hepatic parenchyma through the liver bed. In this article, we describe the indications and our surgical techniques for central bisegmentectomy of the liver plus caudate lobectomy for carcinoma of the gallbladder. We employ combined resection of the caudate lobe, because the caudate lobe often becomes involved even in patients with liver-bed carcinoma. Resection of the extrahepatic bile duct is also required to achieve complete lymphadenectomy within the hepatoduodenal ligament, because tumor invasion of the hepatoduodenal ligament is frequently found. Extensive lymphadenectomy around the head of the pancreas together with removal of the para-aortic lymph nodes should be performed in patients with extensive lymph node metastases.

Gallbladder Neoplasms↗
PubMed1998

Protective effects of baicalein against cell damage by reactive oxygen species.

Baicalein (5,6,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a naturally occurring flavonoid, was found to prevent human dermal fibroblast cell damage induced by reactive oxygen species such as hydrogen peroxide (H2O2), tert-butyl hydroperoxide (BuOOH) and superoxide anions (.O2-) in a concentration-dependent manner, and was more effective than the iron chelator, deferoxamine, hydroxyl radical (.OH) scavengers such as dimethyl sulfoxide (DMSO) and ethanol (EtOH), the lipid peroxidation chain blocker, alpha-tocopherol (Vit. E) and the xanthine oxidase inhibitor, allopurinol. To probe the mechanism of cell defense, the reaction of baicalein with oxygen free radicals was investigated using electron spin resonance (ESR) spectrometry. Baicalein decreased the signal intensities due to the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin adducts of .OH, .O2- and tert-butyl peroxyl (BuOO.) radicals in a concentration-dependent manner. The IC50 values, which are the 50% inhibition concentrations of baicalein for the free radicals, were 10, 45 and 310 microM, respectively. These results suggested that baicalein possesses free radical scavenging ability which prevents the fibroblast damage induced by these free radical species.

Cyclic N-Oxides↗
PubMed1998

Transient left bundle branch block induced by left-sided cardiac catheterization in patients without pre-existing conduction abnormalities.

A traumatic left bundle branch block (LBBB) is uncommon in a patient with intact atrioventricular conduction. Three of our patients developed LBBB during a left-sided catheterization. Two patients suffered from angina pectoris and the other had an abdominal aneurysm. Two of them had a history of hypertension. None of the patients had ever shown any conduction abnormalities before the catheterization. The electrocardiogram just before the examination was normal in all 3 patients. LBBB was observed when a catheter was introduced into the left ventricle, and lasted 2--4 min without significant change in heart rates. Examination revealed no significant stenosis proximal to the first septal perforator and normal left ventricular contraction in all patients. One patient developed permanent LBBB 14 months later. Catheter-induced LBBB may occur easily with certain anatomical characteristics of the left bundle branch or the distal His bundle, with or without some concealed damage to the conduction system. It is important to keep this complication in mind and to pay adequate attention to patients' electrocardiograms as well as their angiographical findings, especially in those with pre-existing right bundle branch block.

Aged↗
PubMed1998

Effects of X-ray irradiation on genomic DNA methylation levels in mouse tissues.

Effects of ionizing radiation on the level of genomic DNA methylation in liver, brain and spleen of mouse as well as in two kinds of cultured cells were examined by high-performance liquid chromatography. Ten Gy of whole body X-radiation reduced the 5-methyldeoxycytidine contents by about 40% within 8 hours after irradiation in liver. Similar effects were observed at 4 or 7 Gy of X-ray irradiation. However, no such change was detected in brain, spleen and cultured cells. The data indicate that radiation-induced alteration in genomic DNA methylation is not ubiquitous among different tissues and cells.

Animals↗
PubMed1998

Molecular cloning and analysis of a lipase gene from Pseudomonas fluorescens No. 33.

The gene encoding an extracellular lipase from Pseudomonas fluorescens No. 33 was cloned and sequenced. A single open reading frame consisting of 1,428 nucleotides that encoded a mature protein of 476 amino acids was recognized. Sequence analysis showed that the deduced molecular weight of 50,209 agreed with the molecular weight of the purified lipase as measured by SDS-PAGE and the lipase lacked a signal peptide. The presence of a repeating motif, GXXGXDXXX, suggested that the lipase might be exported and secreted via a system that involves the ATP-binding cassette protein.

Amino Acid Sequence↗
PubMed1998

The effect of season and melatonin on GnRH-induced LH secretion in oestradiol-treated orchidectomized sheep.

The biphasic effect of oestradiol (E2) on gonadotrope responsiveness is clearly evident in orchidectomized sheep (wethers) receiving E2 and hourly pulses of GnRH. We hypothesized that the duration of E2-induced reduction in gonadotrope responsiveness differed between the breeding (November) and anoestrous (May) seasons in sheep. To test this hypothesis wethers (n = 6/group) were infused (i.v.) with E2 (2 micrograms/50 kg per h) and received hourly pulses of GnRH (200 ng/50 kg per pulse) or saline in May or November. The pattern of LH secretion during the 72 h infusion period was determined. Serum concentrations of LH did not differ with season in control wethers receiving vehicle alone. Similarly, continuous infusion of E2 resulted in a 3-fold reduction in serum LH, irrespective of season. This E2-induced suppression of serum LH was reversed by concurrent episodic delivery of GnRH. The interval between initiation of infusion and return of pretreatment concentrations of LH was taken as a measure of the duration of E2-induced suppression of gonadotrope responsiveness. The duration of this E2-dependent response varied with season, with suppression of gonadotrope responsiveness more prolonged (P < 0.05) in May (36.7 +/- 2.9 h) than in November (14.3 +/- 1.1 h). In a companion study we examined the effect of melatonin on the duration of E2-induced suppression of gonadotrope responsiveness. Wethers received blank or melatonin-containing implants in March. Sixty days after implant insertion (mid-May) wethers received E2 (2 micrograms/50 kg per h) and hourly pulses of GnRH (200 ng/50 kg per pulse) or saline for 72 h. Continuous delivery of E2 alone resulted in a 3-fold decrease in serum concentrations of LH in both control and melatonin-treated wethers. The duration of E2-induced suppression of gonadotrope responsiveness in animals receiving E2 and GnRH was extended (P < 0.05) in wethers with blank implants (48.0 +/- 0.7 h), relative to the duration of suppression in melatonin-treated wethers (14.5 +/- 1.0 h). Taken together these data indicate that E2-induced suppression of gonadotrope responsiveness is more extended during the anoestrous season. However, this seasonal effect can be reversed by continuous administration of melatonin.

Analysis of Variance↗
PubMed1998

Diffusion-weighted magnetic resonance and magnetization transfer imaging in the assessment of ischemic human stroke.

We compared characteristic features in ischemic stroke lesions from the hyperacute to the chronic stage on diffusion-weighted (DW) and magnetization transfer (MT) images with those on T2-weighted (T2W) images, and assessed changes in apparent diffusion coefficient (ADC), MT effect (MTe), and T2 ratios (infarct/normal) over time. DW images were particularly useful for detecting hyperacute infarcts within 6 hours of onset and in distinguishing acute lesions from chronic lesions. ADC ratios were lower within 7 days after onset and rose toward 1.0 in the subacute phase, becoming relatively isotense on ADC maps, but elevated thereafter. Although MTe ratios were unchanged or only subtly changed in the acute stage, they became significantly lower in the subacute and chronic stages. These combined magnetic resonance (MR) techniques were useful in the assessment of ischemic stroke and facilitated the determination of the age of cerebral infarct.

Aged↗
PubMed1998

[Factors that influence the serum of atrial natriuretic peptide and brain natriuretic peptide concentrations--is there a specific marker for senile patients?].

To evaluate factors that influence of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) levels in elderly people, we measured those levels in 54 men and 148 women (84.4 +/- 0.5 years old), and looked for associations of ANP and BNP with clinical factors and echocardiographic variables [left ventricular mass index and atrial to-early peak transmitral velocity ratio (A/E)]. ANP and BNP levels were 1.6 and 6.5 times higher than average. Sex was not a significant factor. We also looked for a link between cardiac rhythms and levels of ANP and BNP. Patients with atrial fibrillation had significantly higher levels of ANP and BNP than did patients with sinus rhythm. ANP and BNP levels were abnormally high in patients with left ventricular hypertrophy (LVH). We could measured A/E in 161 of 202 subjects; 154 of 157 subjects with normal LV systolic function had A/E > 1 which indicates abnormally low in LV diastolic function. Moreover, abnormally high LV diastolic stress might have been present, because 124 of 202 subjects had aortic regurgitation. We divided the patients into two groups: those 65 to 75 years old, and those over 75 years old. The older patients had significantly higher levels of ANP and BNP even without LVH and without a difference in renal function. Furthermore, the older patients had significantly higher levels of BNP even without LVH, with normal renal function, with sinus rhythm, with normal LV systolic function, and in NYHA Class I or II. These data indicate that ANP and BNP levels in people with senility may be associated with the cardiac rhythm and with abnormally low renal function, myocardial hypertrophy, abnormally high cardiac volume, and abnormally low diastolic function.

Aged↗
PubMed1998

Hemofiltration removes bradykinin generated in the priming blood in cardiopulmonary bypass during circulation.

After induction of hemofiltration for the hemic prime of a cardiopulmonary bypass, the initial drop in blood pressure disappears, and postoperative edema rarely occurs. We have suspected that bradykinin, a strong vasodilator generated through the activation of factor XII, prekallikrein, and high molecular weight kininogen was removed by ultrafiltration. We examined the changes in the activities of plasma-factor XII, prekallikrein, high molecular weight kininogen and in the levels of bradykinin in the priming blood using red cell concentrates before and after hemofiltration, and evaluated the effectiveness of hemofiltration. Ten circuits were used, and ten sets of blood samples were collected from red cell concentrates, the priming blood before hemofiltration, after hemofiltration, and the filtrate. During circulation in the circuit, factor XII, prekallikrein and high molecular weight kininogen were completely consumed and a large amount of bradykinin was generated, but it was filtered well by ultrafiltration. Factor XII, prekallikrein and high molecular weight kininogen could be activated through the dilution of red cell concentrates during the priming and contact with the circuits. Because bradykinin is the most potent vasodilator, increasing microvascular permeability and relating to several other inflammatory mediators, the removal of bradykinin generated from factor XII, prekallikrein and high molecular weight kininogen is very significant in the prevention of non-specific inflammatory reactions during and after open-heart surgery.

Bradykinin↗
PubMed1998

[An infant with lobar emphysema requiring lobectomy after ventricular septal defect closure].

A 1-month-old male infant with respiratory distress was referred to our hospital for operation of the ventricular septal defect. A chest roentgenogram demonstrated pulmonary emphysema especially in the right upper and middle lobes. At 3 months, a perimembranous ventricular septal defect was closed. But the infant could not be weaned from the ventilator. On the 21st postoperative day, a right upper and middle bilobectomy was performed. Three days later, he was weaned from the ventilator and the postoperative course was uneventful. The pathologic diagnosis revealed no bronchial cartilagenous abnormality. Infantile lobar emphysema of the right upper lobe with congenital heart disease is rather rare. We emphasize the need for lobectomy simultaneous with, secondary to, cardiac surgery in these cases.

Heart Septal Defects, Ventricular↗
PubMed1998

[A case of primary squamous cell lung cancer invading the wall of the distal aortic arch and the left subclavian artery: successful surgical management using ECC with selective cerebral perfusion].

A 37-year-old male was referred to our hospital with symptoms suggesting pneumonia. The preoperative diagnosis was primary lung cancer of the left upper lobe invading the distal aortic arch (DAA) (T4, stage IIIB). Complete resection was performed with associated resection of the pneumonectomy, DAA, and left subclavian artery. Dacron graft replacement was performed using ECC with selective cerebral perfusion. Histological examination revealed squamous cell carcinoma, n1 and negative surgical margins. We expect this patient to achieve long-term survival. We conclude that ECC with selective cerebral perfusion is both safe and effective for pulmonary surgery in cases with combined resection of the DAA.

Adult↗
PubMed1998

A case successfully treated by conservative management for mediastinitis and infected composite graft due to methicillin-resistant coagulase negative staphylococcus.

A 72 year-old man underwent a Bentall procedure for aortic regurgitation secondary to annulo-aortic ectasia and ascending aortic aneurysm. On the 11th postoperative day, the C-reactive protein (CRP) level and white blood cell (WBC) count rose. Echocardiography and a computed tomographic scan showed the appearance of pericardial effusion. A diagnosis of mediastinitis and composite graft infection was made, and mediastinal drainage and irrigation were performed. Methicillin-resistant coagulase negative staphylococcus (MRCNS) was identified as the causative organism. Vancomycin, arbekacin and minocycline were used intravenously. Additionally, a continuous mediastinal irrigation was performed through the chest tubes. CRP level and WBC count were gradually reduced to normal range. He has now been free from signs of infection for more than 3 years. Because MRCNS is considered less virulent than methicillin-resistant Staphylococcus aureus, mediastinitis and composite graft infection due to MRCNS might be treatable by such conservative therapy even in patients with prosthetic implants. Since MRCNS often becomes ubiquitous, preventing infections by strict attention to asepsis is important.

Aged↗
PubMed1998

A cross-sectional observation of the health effects of hydrazine hydrate and differences of its metabolism by NAT2 polymorphism.

OBJECTIVES: To summarize the results of two studies that attempted to clarify: (1) the health effects of hydrazine hydrate (HH) (N2H4 x H2O: CAS No. 7803-57-8); and (2) the influence of allelic polymorphism of N-acetyltransferase (NAT2) on the metabolism of HH. METHODS: A cross-sectional survey was carried out on 172 male HH-exposed workers and 125 male referent workers at five factories in Japan. The biological half-lives of HH after 1 h of exposure were determined in 12 workers, four workers in each of three NAT2 phenotypes. Clinical examinations were performed and acute and chronic subjective symptoms related to HH were examined by self-administered questionnaires. NAT2 phenotypes were assessed. RESULTS: No hydrazine was detected in either the breathing zones or the urine of the referent workers. The mean hydrazine concentration in the breathing zones, hydrazine and acetylhydrazine in urine, and the cumulative exposure level were 0.0109 ppm, 0.8660 micromol/g x Cr, and 2.80 ppm-years, respectively. There was no difference and no dose-dependent change in the health examination items between HH-exposed and referent workers after adjusting confounding factors, nor in terms of the differences of NAT2 phenotypes. Of 90 subjective symptoms, complaints of nightmares were significantly related to HH exposure. The half-life of urinary hydrazine and acetylhydrazine on rapid, intermediate, and slow phenotypes was 1.68, 3.01, and 4.46 h, respectively. CONCLUSION: This study suggested that current and cumulative exposure to HH did not affect the workers' health, and the half-life of the slow phenotype was longer than those of the rapid and intermediate phenotypes.

Adolescent↗
PubMed1997

Suppression of NF-kappa B and AP-1 activation by glucocorticoids in experimental glomerulonephritis in rats: molecular mechanisms of anti-nephritic action.

Transcription factors nuclear factor-kappa B (NF-kappa B) and activator protein-1 (AP-1) play an important role in the induction of pro-inflammatory factors such as cytokines and cell adhesion molecules, which could be involved in the pathogenesis of glomerulonephritis. We have recently reported the pathogenic significance of NF-kappa B activation in experimental glomerulonephritis in rats. In this study, we investigated the pathogenic relevance of AP-1 activation in nephrotoxic serum (NTS)-induced glomerulonephritis. Increased AP-1 DNA-binding activity was detected in nephritic glomeruli by a gel shift assay. The kinetics of AP-1 activation was similar to that of NF-kappa B. Activation of both NF-kappa B and AP-1 preceded proteinuria, an important pathophysiological parameter for glomerulonephritis. Treatment with prednisolone, a glucocorticoid hormone, prevented activation of both NF-kappa B and AP-1 in glomeruli and subsequent mRNA expression of NF-kappa B- and AP-1-regulated genes. Prednisolone was also effective therapeutically and reduced DNA-binding activities of NF-kappa B and AP-1 which are already activated in nephritic glomeruli. These results suggest that activated NF-kappa B and AP-1 may play an important pathogenic role in glomerulonephritis and the anti-nephritic action of glucocorticoids may be mediated through the suppression of these transcription factors.

Animals↗
PubMed1997

Yeast Gal11 and transcription factor IIE function through a common pathway in transcriptional regulation.

The global transcription regulator Gal11, a component of RNA polymerase II holoenzyme, is required for full expression of many genes in yeast. We previously reported that Gal11 binds the small (Tfa2) and large (Tfa1) subunits of the general transcription factor (TF) IIE through Gal11 functional domains A and B, respectively. Here we demonstrate that the C-terminal basic region in Tfa2 is responsible for binding to domain A, whereas both the N-terminal hydrophobic and internal glutamic acid-rich regions in Tfa1 are responsible for binding to domain B. Yeast cells bearing a C-terminal deletion encompassing the Gal11-interacting region in each of the two TFIIE subunits, being viable, exhibited no obvious phenotype. In contrast, combination of the two deletions (TFIIE-DeltaC) showed phenotypes similar to those of gal11 null mutations. The levels of mRNA from TATA-containing genes, but not from TATA-less genes, decreased in TFIIE-DeltaC to an extent comparable to that in the gal11 null mutant. Combination of TFIIE-DeltaC with a gal11 null mutation did not result in an enhanced effect, suggesting that both TFIIE and Gal11 act in a common regulatory pathway. In a reconstituted cell-free system, Gal11 protein stimulated basal transcription in the presence of wild-type TFIIE. Such a stimulation was not seen in the presence of TFIIE-DeltaC.

Cell-Free System↗