Search PubMed⌕ Search

Biomedical subjects

M Hirata

Publications and source records attributed to M Hirata.

At least 145 records · Page 8Linked to original sources
PubMed1999

Cardiac rhythms in chick embryos during hatching.

Avian embryos develop within a hard eggshell which permits the measurement of heart rate while maintaining an adequate gas exchange through the chorioallantoic membrane. Heart rate has been determined from cardiogenic signals detected either noninvasively, semi-invasively or invasively with various transducers. Firstly, we reviewed these previously-developed methods and experimental results on heart rate fluctuations in prenatal embryos. Secondly, we presented new findings on the development of heart rate fluctuations during the last stages of incubation, with emphasis on the perinatal period, which remained to be studied. Three patterns of acceleration of the instantaneous heart rate were unique to the external pipping period: irregular intermittent large accelerations, short-term repeated large accelerations and relatively long-lasting cyclic small accelerations. Besides these acceleration patterns, respiratory arrhythmia, which comprimised oscillating patterns with a period of 1-1.5 s, appeared during the external pipping period. Furthermore, additional oscillating patterns with a period of 10-15 min were found in some externally pipped embryos.

Animals↗
PubMed1999

Characteristics of eosinophilic inclusions within Schistosoma japonicum eggs.

Although eosinophilic bar- or droplet-like inclusions are frequently detectable inside eggs deposited in the livers of Schistosoma japonicum-infected animals, little is known of their exact nature. In the livers of mice implanted with freshly laid eggs, inclusion-positive eggs were found in 28.7 and 46.2% of deposited eggs at 2 and 4 weeks, respectively, after implantation, but in 4.3% at 5 weeks when most of the eggs had already degenerated. When the extent of granuloma formation was investigated, granulomas around inclusion-positive eggs were smaller than those around negative eggs. Host factors associated with the formation of inclusion were sought using in vivo and in vitro studies. Following the administration of anti-egg antigen serum into egg-implanted mice, no increase in occurrence of inclusion-positive eggs was seen. In a co-culture of mature eggs with infected rabbit or mouse serum, inclusions were rarely found. In contrast, they were found in 17.9% of eggs in the presence of splenic cells. The present study is the first to show that there is decreased granuloma formation in the presence of eosinophilic inclusions inside eggs and our in vitro study suggests that host cell-egg interaction is responsible for the formation of inclusions.

Animals↗
PubMed1999

22-Oxacalcitriol ameliorates high-turnover bone and marked osteitis fibrosa in rats with slowly progressive nephritis.

UNLABELLED: 22-Oxacalcitriol ameliorates high-turnover bone and marked osteitis fibrosa in rats with slowly progressive nephritis. BACKGROUND: 22-Oxacalcitriol (OCT) is a unique vitamin D analogue with less calcemic activity than calcitriol, and it effectively suppresses parathyroid hormone (PTH) secretion in uremic rats. This study was performed to examine the long-term effect of intravenously administered OCT on high-turnover bone disease in model rats of slowly progressive renal failure. METHODS: Slowly progressive renal failure rats were made by a single injection of glycopeptide isolated from rat renal cortical tissues. At 250 days, glycopeptide-induced nephritis (GN) rats were divided into three groups with the same levels of serum creatinine and PTH, and they received either OCT (0.03 or 0.15 microg/kg body wt) or vehicle given intravenously three times per week for 15 weeks. RESULTS: Renal function of GN rats deteriorated very slowly but progressively, as assessed by the increase of serum creatinine concentration. At sacrifice, serum PTH levels, bone formation markers, bone resorption markers, and fibrosis volume were significantly elevated in vehicle-treated GN rats compared with those of sham-operated rats, suggesting the development of high-turnover bone disease with osteitis fibrosa. In contrast, in the GN-OCT 0.15 microg/kg group, these high PTH levels and high-turnover bone and fibrosis were significantly decreased. Such amelioration of bone abnormalities by OCT was not accompanied by either hypercalcemia or further deterioration of renal function. CONCLUSIONS: These data indicate that OCT may be a useful and safe agent not only for the suppression of PTH, but also for the amelioration of osteitis fibrosa and high-turnover bone without causing hypercalcemia in chronic dialysis patients.

Animals↗
PubMed1999

Purification, molecular cloning, and genomic organization of human brain long-chain acyl-CoA hydrolase.

An acyl-CoA hydrolase, referred to as hBACH, was purified from human brain cytosol. The enzyme had a molecular mass of 100 kDa and 43-kDa subunits, and was highly active with long-chain acyl-CoAs, e.g. a maximal velocity of 295 micromol/min/mg and K(m) of 6.4 microM for palmitoyl-CoA. Acyl-CoAs with carbon chain lengths of C(8-18) were also good substrates. In human brain cytosol, 85% of palmitoyl-CoA hydrolase activity was titrated by an anti-BACH antibody, which accounted for over 75% of the enzyme activity found in the brain tissue. The cDNA isolated for hBACH, when expressed in Escherichia coli, directed the expression of palmitoyl-CoA hydrolase activity and a 44-kDa protein immunoreactive to the anti-BACH antibody, which in turn neutralized the hydrolase activity. The hBACH cDNA encoded a 338-amino acid sequence which was 95% identical to that of a rat homolog. The hBACH gene spanned about 130 kb and comprised 9 exons, and was mapped to 1p36.2 on the cytogenetic ideogram. These findings indicate that the long-chain acyl-CoA hydrolase present in the brain is well conserved between man and the rat, suggesting a conserved role for this enzyme in the mammalian brain, and enabling genetic studies on the functional analysis of acyl-CoA hydrolase.

Adult↗
PubMed1999

The molecular weight ratio of monomethoxypolyethylene glycol (mPEG) to protein determines the immunotolerogenicity of mPEG proteins.

Immunotolerogenic activity of monomethoxypolyethylene glycol- (mPEG) conjugated proteins is a beneficial property in protein pharmaceutics. However, procedures for the preparation of tolerogenic mPEG proteins have not yet been defined. We prepared mPEG proteins with different mPEG contents using three proteins, hen egg lysozyme, ovalbumin and bovine gamma globulin, and their tolerogenicities to antigen-specific T and B cell responses were examined. We found the most appropriate ratio of tolerance induction to be 1.5-2.0, which is the molecular weight ratio of conjugated total mPEGs to protein. This value may assist in the preparation of tolerogenic mPEG proteins.

Animals↗
PubMed1999

Retrograde temporal order amnesia resulting from damage to the fornix.

Some amnesic patients show an impairment of temporal order memory that cannot be accounted for by content memory deficits. The performance of an amnesic patient on memory tasks assessing the patient's content and temporal memories for remotely acquired material is described, after a lesion including the bilateral anterior fornix and adjacent anterior thalamus. The patient displayed a deficit in the temporal order tasks for remotely acquired information. Neither frontal cognitive deficits nor recognition deficits can account for this patient's poor temporal memory. This retrograde temporal order memory impairment without content memory deficits were not seen in previously reported thalamic amnesic patients. Accordingly, the present patient's poor retrograde temporal memory could hardly be explained by only a thalamic lesion. It is concluded that the patient's impairment of temporal order memory for the retrograde material is probably due to the direct disconnection between the frontal lobe and the hippocampus by disruption of the fornix.

Amnesia↗
PubMed1999

Genomic structure and chromosome location of RPL27A/Rpl27a, the genes encoding human and mouse ribosomal protein L27A.

The intron-containing genes encoding human and mouse ribosomal protein (r-protein) L27A were cloned and sequenced. The human r-protein L27A gene (RPL27A) shared an identical exon/intron structure with the mouse r-protein 27A gene (Rpl27a). The translational start codon ATG was separated from the main reading frame by the first intron sequence in both genes. An approximately 200-bp sequence upstream of the translational start site of both genes displayed remarkable similarity, and contained the putative promoters lacking canonical TATA, but harbored Sp1 binding sites and a short stretch of pyrimidine cluster, similar to other r-protein genes. Transcriptional regulatory elements, Box-A and GABP, found in the promoters of some other r-protein genes were also conserved in both genes. These structural features were included in the typical CpG island identified in the 5'-end sequences, suggesting that RPL27A/Rpl27a cloned here are authentic and transcriptionally active. Fluorescence in situ hybridization (FISH) analysis localized the mouse intron-containing Rpl27a to chromosome 7E2-F1 syntenic to human chromosome 11p15, where human RPL27A was located.

Animals↗
PubMed1999

Cephalometric abnormalities in non-obese and obese patients with obstructive sleep apnoea.

The aim of this work was to comprehensively evaluate the cephalometric features in Japanese patients with obstructive sleep apnoea (OSA) and to elucidate the relationship between cephalometric variables and severity of apnoea. Forty-eight cephalometric variables were measured in 37 healthy males and 114 male OSA patients, who were classed into 54 non-obese (body mass index (BMI) <27 kg x m(-2), apnoea-hypopnoea index (AHI)=25.3+/-16.1 events x h(-1)) and 60 obese (BMI > or = 27 kg x m(-2), AHI=45.6+/-28.0 events h(-1)) groups. Diagnostic polysomnography was carried out in all of the OSA patients and in 19 of the normal controls. The non-obese OSA patients showed several cephalometric defects compared with their BMI-matched normal controls: 1) decreased facial A-P distance at cranial base, maxilla and mandible levels and decreased bony pharynx width; 2) enlarged tongue and inferior shift of the tongue volume; 3) enlarged soft palate; 4) inferiorly positioned hyoid bone; and 5) decreased upper airway width at four different levels. More extensive and severe soft tissue abnormalities with a few defects in craniofacial bony structures were found in the obese OSA group. For the non-obese OSA group, the stepwise regression model on AHI was significant with two bony structure variables as determinants: anterior cranial base length (S-N) and mandibular length (Me-Go). Although the regression model retained only linear distance between anterior vertebra and hyoid bone (H-VL) as an explainable determinant for AHI in the obese OSA group, H-VL was significantly correlated with soft tissue measurements such as overall tongue area (Ton), inferior tongue area (Ton2) and pharyngeal airway length (PNS-V). In conclusion, Japanese obstructive sleep apnoea patients have a series of cephalometric abnormalities similar to those described in Caucasian patients, and that the aetiology of obstructive sleep apnoea in obese patients may be different from that in non-obese patients. In obese patients, upper airway soft tissue enlargement may play a more important role in the development of obstructive sleep apnoea, whereas in non-obese patients, bony structure discrepancies may be the dominant contributing factors for obstructive sleep apnoea.

Adult↗
PubMed1999

[Actual conditions of occupational health activities in small-scale enterprises in Japan: system for occupational health, health management and demands by small-scale enterprises].

In order to clarify the real conditions of occupational health services (OHS) in small-scale enterprises (SSEs) in Japan, we analyzed questionnaires recovered from 765 SSEs in the area of a city neighboring Osaka City (recovery rate, 69.3%). The SSEs included 358 SSEs with 1 to 4 workers (46.8% of total SSEs), 203 with 5 to 9 (26.5%), 163 with 10 to 29 (21.3%) and 41 with 30 to 49 (5.4%). The main types of businesses were manufacturing (374, 48.9% of total SSEs), wholesale/retail trade/restaurants (153, 20.0%), community, social and personal services (132, 17.3%) and construction (72, 9.4%). Health examinations were performed in 47.7% of SSEs. The reason for the lack of examinations were "shortage of time" (33.3% of SSEs lacking health examination) and "employees do not want to be examined" (28.1%). Some health promotion measures were conducted in 29.2% of SSEs. Health examination (59.0% of SSEs), health promotion (36.5%), measure of mental health (25.9%) and information service for employers and employees (25.5%) were demanded by SSEs as OHS. Financial subsidies and economical incentives were demanded by 46.4% and 28.8% of SSEs, respectively. Regional occupational health center in this area was poorly known among SSEs (8.2%), but health examination (48.4%), information service (37.5%), assessment of work method and advice to improve (19.8%) and environment measurement (12.4%) are demanded of the center by SSEs.

Female↗
PubMed1999

A three-month repeated oral administration study of a low viscosity grade of hydroxypropyl methylcellulose in rats.

The toxicity of the lowest viscosity grade of hydroxypropyl methylcellulose (HPMC) that is currently commercially available was investigated by means of a three-month repeated oral administration study in male and female Crj:CD (SD) IGS rats at doses of 505, 1,020 and 2,100 mg/kg/day. Body weights of males and females in the 2,100 mg/kg group were lower than those of the control group on and after day 28 of administration, but the differences were not statistically significant. The degree of suppression of body weight gain in males was higher than that in females. This tendency was similar to the results in other toxicity studies of HPMC that have been reported. Males in the 2,100 mg/kg group showed a tendency (not significant) for decreased food consumption and urine volume. Examinations of general signs, hematology, blood chemistry, ophthalmology, absolute and relative organ weights, autopsy and histopathology revealed only a few, apparently coincidental, statistically significant differences from the control, and no evidence of any dose-dependent changes was found. It was concluded that the lowest viscosity grade of HPMC showed extremely low toxicity under the conditions of this study, as has been found for higher viscosity grades.

Administration, Oral↗
PubMed1999

Application of a rigid endoscope to the microsurgical management of 54 cerebral aneurysms: results in 48 patients.

OBJECT: To enhance visual confirmation of regional anatomy, endoscopy was introduced during microsurgery for cerebral aneurysms. The risks and benefits are analyzed in the present study. METHODS: The endoscopic technique was used during microsurgery for 54 aneurysms in 48 patients. Forty-three aneurysms were located in the anterior circulation and 11 were in the posterior circulation. Thirty-eight aneurysms (70.4%) had not ruptured. All ruptured aneurysms in the present series produced Hunt and Hess Grade I or II subarachnoid hemorrhage. After initial exposure achieved with the aid of a microscope, the rigid endoscope was introduced to confirm the regional anatomy, including the aneurysm neck and adjacent structures. The necks of 43 aneurysms were clipped using microscopic control or simultaneous microscopic/endoscopic control. After clipping, the positions of the clip and nearby structures were inspected using the endoscope. Use of the neuroendoscope provided useful information that further clarified the regional anatomy in 44 cases (81.5%) either before or after neck clipping. In nine cases (16.7%), these details were available only with the use of the endoscope. In five cases (9.3%), the surgeons reapplied the clip on the basis of endoscopic information obtained after the initial clipping. There were two cases in which surgical complications were possibly related to the endoscopic procedures (one patient with asymptomatic cerebral contusion and another with transient oculomotor palsy). CONCLUSIONS: It is the authors' impression that the use of the endoscope in the microsurgical management of cerebral aneurysms enhanced the safety and reliability of the surgery. However, there is a prerequisite for the surgeon to be familiar with this instrumentation and fully prepared for the risks and inconveniences of endoscopic procedures.

Adult↗
PubMed1999

Cholecystokinin regulates the invasiveness of human pancreatic cancer cell lines via protein kinase C pathway.

We have previously reported that cholecystokinin (CCK) plays an important role in the invasiveness and the production of matrix metalloproteinase-9 (MMP-9) in two human pancreatic cancer cell lines. In this study we investigated the pathway of the invasiveness associated with MMP-9 of those lines regulated by CCK. Two human pancreatic cancer cell lines were treated with CCK-8 alone, CCK-8 and staurosporine, or CCK-8 and indomethacine. The invasiveness and the production of MMP-9 were decreased with staurosporine but not indomethacine. These results suggest that CCK may regulate the invasiveness and the production of MMP-9 via protein kinase C in human pancreatic cancer cell lines.

Blotting, Western↗
PubMed1999

Intrinsic inhibitor of inositol 1,4,5-trisphosphate binding.

Rat brain cytosol was applied to a heparin column and eluted with 0.9 M-NaCl. The total binding activity of [3H]inositol 1,4,5-trisphosphate to the eluate was increased about 6-fold compared with the original cytosol. When the eluate was mixed with a flow-through fraction from the heparin column, however, the activity returned to the original level, suggesting that the flow-through fraction contained an inhibitory factor(s) which prevented the binding. The factor(s) was purified by sequential column chromatography using gel permeation, a hydrophobic gel, and finally, a hydroxylapatite gel. Silver staining of sodium dedecyl sulfate gel electrophoresis of the sample thus purified showed a broad band located between the authentic molecular weight markers of 580 and 390 k. A carbohydrate staining method showed that the factor is a glycoprotein.

Animals↗
PubMed1999

Effects of alcohol intake and low Km aldehyde dehydrogenase on hepatic function in a high hepatitis C virus-prevalent Japanese island population.

In Asians from the Pacific rim countries, alcohol sensitivity has been attributed mainly to a highly prevalent polymorphism in low Km aldehyde dehydrogenase (ALDH2). Chronic alcohol abuse may accelerate or aggravate the liver injury in chronic hepatitis C virus (HCV)-infected subjects. In this study, we examined the relationships among alcohol intake, ALDH2 genotypes, and liver injury in a high HCV-prevalent Japanese native island population. The ALDH2 genotypes are significantly associated with drinking habits. In HCV RNA positive subjects, serum alanine aminotransferase (ALT), as well as aspartate transaminase (AST) and gamma-glutamyl transpeptidase (GGT), were significantly higher in habitual drinkers than in nonhabitual drinkers. In male habitual drinkers, the ALDH2*1/*1 subjects had higher liver necroinflammatory scores than the ALDH2*1/*2 subjects in all groups classified as: I, anti-HCV-seronegative; II, anti-HCV-seropositive with negative HCV RNA; and III, HCV RNA positive, although scores for the latter two groups were not statistically significant because of limited sample size. It was suggested that the liver function might be affected by the interaction between the ALDH2 genotypes and alcohol intake. These findings indicate that HCV-infected ALDH2*1/*1 habitual drinkers are the major target for the prevention of alcoholic liver diseases.

Alcohol Drinking↗
PubMed1999

[Cerebral venous thrombosis in minimal change nephrotic syndrome].

A 46-year old man presented with an eight-day history of edema and was found to be nephrotic, with a plasma albumin level of 1.1 g/dl and urine protein excretion of 13.3 g/24 hrs. The level of plasma creatinine was normal at 1.0 mg/dl. A finding of renal biopsy was consistent with minimal change glomerulopathy. On the 6th hospital day, he suddenly developed a severe headache and was noted to have bilateral papilledema. Lumbar puncture revealed an opening pressure of 250 mm of water. Magnetic resonance venography showed an irregular flow in the superior sagittal sinus and right transverse sinus, a finding consistent with thrombus. The diagnosis of cerebral venous thrombosis was made, and the patient was given both Warfarin 2 mg/day and prednisolone 60 mg/day. A complete recovery from nephrotic syndrome was achieved within eight weeks. Nephrotic syndrome causes a hypercoagulable state, leading to both venous and arterial thrombosis. The most common clinical features are renal vein thrombosis, femoral vein thrombosis, and pulmonary embolism, however, cerebral venous sinus thrombosis is rare in patients with nephrotic syndrome. It is important to be aware of this complication, since prompt treatment with anticoagulation and control of nephrotic syndrome can lead to a successful outcome.

Anti-Inflammatory Agents↗
PubMed1999

Usefulness of cytofluorometric DNA ploidy analysis in distinguishing benign cartilaginous tumors from chondrosarcomas.

In this study, we undertook to prove the usefulness of cytofluorometric DNA ploidy analysis in distinguishing benign cartilaginous tumors from chondrosarcomas. We analyzed the DNA ploidy of 47 cartilaginous tumors using DNA cytofluorometry, which is more sensitive than flow cytometry. All of these tumors were classified into six groups on the basis of clinical, radiologic, and histologic criteria. The 25 tumors in the No. 1 group showed no histologic signs of malignancy regardless of their clinical signs. The four tumors in the No. 2 group showed histologic signs of malignancy, but had benign clinical signs like small bone origin or Ollier's disease. The No. 3 group (13 tumors), No. 4 group (four tumors), and No. 5 group (three tumors) were conventional grade I, II, and III chondrosarcomas, respectively, and the No. 6 group included three dedifferentiated chondrosarcomas. Tumor cells isolated from fresh tumor materials treated with papain and collagenase were smeared on a glass slide and their nuclear DNA was stained with propidium iodide. The DNA content of each cell was measured by a cytofluorometer as fluorescence intensity. The results of this study showed that all of the tumors in the No. 1 group had a diploid pattern with a significantly lower (P<.001) cell proliferative activity than the grade I chondrosarcomas in the No. 3 group, all of which had a diploid pattern. Cytofluorometric analysis also indicated that grade II and III chondrosarcomas in the No. 4 and 5 groups had a higher frequency of hyperdiploid cells (%HDC), including aneuploid and polyploid cells than grade I chondrosarcomas. Importantly, all of the grade I chondrosarcomas showed a %HDC >8%, whereas all of the tumors in the No. 1 and 2 groups showed a %HDC <8%. Therefore, we believe that a %HDC value of 8% is borderline between biologically benign and malignant states in cartilaginous tumors. Four of five patients with aneuploid chondrosarcoma had tumor recurrence and two of these patients died of metastatic disease, although all of the patients except for one with diploid chondrosarcoma were continuously disease free after surgery. Based on these results, we concluded that the data of DNA ploidy analysis, especially cell proliferative activity expressed as %HDC, is more reliable and clinically more useful than the histologic and clinical signs of malignancy in distinguishing benign cartilaginous tumors from chondrosarcomas and even from low grade chondrosarcomas.

Adult↗