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Biomedical subjects

Y Sakurai

Publications and source records attributed to Y Sakurai.

At least 343 records · Page 19Linked to original sources
PubMed1993

Purification and characterisation of haemagglutinin from Bordetella bronchiseptica.

A surface protein of Bordetella bronchiseptica was purified in one step by affinity chromatography with bovine submaxillary mucin coupled to agarose. The purified protein, with a mol. wt of 200 kDa and an iso-electric point of pI 6.5, showed haemagglutinating activity for bovine erythrocytes. This haemagglutinin (HA) inhibited the adherence of B. bronchiseptica to a rat lung cell line (L2) and was able to bind to N-acetylneuraminic acid. These findings suggest that the HA of B. bronchiseptica is an adhesin.

Animals↗
PubMed1993

Progressive alterations in lipid and glucose metabolism during short-term fasting in young adult men.

Stable isotope tracers and indirect calorimetry were used to evaluate the progressive alterations in lipid and glucose metabolism after 12, 18, 24, 30, 42, 54, and 72 h of fasting in six healthy male volunteers. The rates of appearance (Ra) of glycerol and palmitic acid in plasma doubled from 2.08 +/- 0.22 and 1.63 +/- 0.20 mumol.kg-1 x min-1, respectively, after 12 h to 4.36 +/- 0.36 and 3.26 +/- 0.40 mumol.kg-1 x min-1, respectively, after 72 h of fasting (P < 0.01). Of the total increase in lipid kinetics, 60% occurred between 12 and 24 h of fasting; the greatest interval change occurred between 18 and 24 h of fasting. Glucose Ra and plasma concentration decreased by approximately 25% between 12 h (11.0 +/- 0.4 mumol.kg-1 x min-1 and 5.58 +/- 0.08 mmol/l, respectively) and 72 h (8.3 +/- 0.3 mumol.kg-1 x min-1 and 4.14 +/- 0.10 mmol/l, respectively) of fasting (P < 0.01), but no statistically significant changes occurred between 18 and 24 h of fasting. Plasma insulin decreased by approximately 50% between 12 h (64.6 +/- 12.9 pmol/l) and 72 h (30.1 +/- 7.9 pmol/l) of fasting (P < 0.001). Of the total decline in plasma insulin, 70% occurred within the first 24 h of fasting. These results demonstrate that the mobilization of adipose tissue triglycerides increases markedly between 18 and 24 h of fasting in young adult men. The early alterations in lipid metabolism are associated with a decline in circulating insulin but do not seem to be regulated by changes in glucose kinetics or plasma glucose concentrations.

Adult↗
PubMed1993

Swelling controlled zero order and sigmoidal drug release from thermo-responsive poly(N-isopropylacrylamide-co-butyl methacrylate) hydrogel.

Thermo-responsive hydrogels of poly(N-isopropylacrylamide-co-butyl methacrylate) (poly-(IPAAm-co-BMA)) are capable of swelling-deswelling changes in response to external temperature. As poly(IPAAm-co-BMA) gels swell larger at a lower temperature, the degree and rate of the swelling could be controlled by temperature without altering the chemical structure. Therefore, drug release profiles were remarkably changed by alternation of temperature. The release profiles of indomethacin from poly(IPAAm-co-BMA) were observed to be zero-order at 20 degrees C. This release profile was explained in terms of a Case-II diffusion mechanism; which indicates relaxation of polymer chains with swelling was rate-determining. In the case of 10 degrees C, release demonstrated a sigmoidal profile. The acceleration of drug release was due to a rapid increase in swelling with disappearance of the glassy core which had constrained swelling. The regulation of the water-uptake process by changing external temperature remarkably affected drug release and resulted in several different release profiles.

Acrylic Resins↗
PubMed1993

Mechanism of cytoplasmic calcium changes in platelets in contact with polystyrene and poly(acrylamide-co-methacrylic acid) surfaces.

Changes in cytoplasmic free calcium levels ([Ca2+]i) in platelets in contact with polystyrene (PSt) and poly(acrylamide-co-methacrylic acid) (PAAmMAc) particles were evaluated and results were compared with those from two representative biological calcium agonists; thrombin and calcium ionophore A23187. PSt particles stimulated a steep increase in cytoplasmic calcium levels in platelets as much as thrombin and A23187. Serratia protease-treated platelets showed a steep increase in [Ca2+]i by PSt particles, suggesting that PSt surfaces can initiate platelet activation independent of a glycoprotein Ib (GPIb)-mediated pathway. By contrast, dibucaine-treated platelets showed little increase in [Ca2+]i by PSt particles, indicating that microfilament assembly, including binding of GPIb with actin binding protein, should be required for platelet activation in contact with PSt surfaces. PAAmMAc particles induced little increase in cytoplasmic calcium levels in platelets. However, PAAmMAc particle-treated platelets demonstrated little response to thrombin in terms of an increase in [Ca2+]i and ATP release, suggesting the possibility that PAAmMAc surfaces may regulate [Ca2+]i by influencing platelet metabolism. Furthermore, sodium azide-treated platelets showed an increase in [Ca2+]i in platelets when contacting PAAmMAc particles, supporting the suggestion that PAAmMAc surfaces could regulate platelet functions. Fluorescence polarization measurements using 1,6-diphenyl-1,3,5-hexatriene-loaded platelets revealed that PAAmMAc particles increased membrane fluidity in platelets, which may be due to physicochemical interaction with PAAmMAc surfaces.

Acrylic Resins↗
PubMed1993

Short-term effects of tumor necrosis factor on energy and substrate metabolism in dogs.

In vivo short-term effects of recombinant human TNF-alpha on lipolysis, FFA flux, fat oxidation, triglyceride-fatty acid cycling, and glucose kinetics were evaluated with stable isotopic tracers and indirect calorimetry along with monitoring of hemodynamic parameters in fasted dogs. High-dose TNF infusion (10 micrograms/kg) caused a fall in mean arterial pressure (P < 0.01), pulmonary arterial pressure (P < 0.001), and cardiac index (CI) (P < 0.05). The rate of appearance of glycerol (Ra glycerol) and the rate of appearance of FFA (Ra FFA) were decreased by 20% (P < 0.05) and by 42% (P < 0.01), respectively. Total fat oxidation fell by 23% (P < 0.05). In contrast, TNF infusion significantly increased glucose production by 13% (P < 0.05) and metabolic clearance rate of glucose by 25% (P < 0.01). However, TNF infusion did not change energy expenditure. Low-dose TNF infusion (3.5 micrograms/kg) caused changes similar in all respects, except magnitude, to the high-dose effects. There was a significant correlation between percent change of CI (delta CI) and percent change of rate of appearance of palmitate (Ra palmitate; delta Ra palmitate) (P < 0.0001, r = 0.69), Ra FFA (delta Ra FFA) (P < 0.0001, r = 0.60), and Ra glycerol (delta Ra glycerol) (P < 0.0329, r = 0.36). The correlation between delta CI and delta Ra palmitate was greater than the correlation between delta CI and delta Ra glycerol (P = 0.028). We conclude that the acute response to TNF causes a shift towards carbohydrate as an energy substrate in a dose-dependent manner by both decreasing the availability of FFAs and increasing glucose production.

Animals↗
PubMed1993

[Inbreeding process and establishment of new inbred lines derived from the Japanese house mouse, Mus musculus molossinus].

Inbreeding of 8 groups in molossinus mouse began in (Miura female x Urawa male) F1 (MU) from the stock captured in the Kanto district of Japan and were accomplished by each primiparous littermates. The animals were kept under a clean conventional condition at 23.5 +/- 2.5 degrees C and 50 +/- 5% in relative humidity. Pellet feed, CRF-1, and tap water were provided ad libitum. The respective number of inbreeding generations of MUA, MUF and MUG now exceeds F21, F20 and F22, respectively. Inbreeding of MUD and MUE have reached to F18 up to now, but the other 3 groups became extinct at F10. Time required for inbreeding from F0 to F20 was 2,280 days for MUA, 2,454 days for MUF and 2,143 days for MUG. Generation time was 114.0 +/- 47.2 days for MUA, 122.7 +/- 54.6 days for MUF and 107.2 +/- 48.5 days for MUG. Though the generation time varied from a minimum of 60 days to a maximum of 258 days from F0 to F10 in the inbreeding process (mean: 150.2 +/- 41.7 days), which were shortened from F10 and the mean was 79.0 +/- 29.1 days. In the breeding of the molossinus mouse, primiparous age was 124.5 +/- 29.7 days from F0 to F9 and 77.8 +/- 9.3 days from F10 to F19. The litter size was 5.1 +/- 1.3 for MUA and 5.0 +/- 1.3 for MUG in offspring, 5.0 +/- 1.2 and 4.9 +/- 1.2 in weanling, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1993

[Changes in body weight, food and water intake, organ indices and tissue component parts with growth in the established inbred lines derived from the Japanese house mouse, Mus musculus molossinus].

Changes in body weight, food and water intake, organ indices and tissue component parts with growth in the inbred lines of the molossinus mouse were examined. The characteristic for the mouse is to be very small in body weight; the body weights linearly increased from neonatal period to 1 month and also increased with age, but became constant after 7 months (19.9 +/- 1.6 g) for male and 9 months (19.3 +/- 0.7 g) for female. Maximum body weight was 21.5 g for the male and 20.1 g for the female. Food and water intake per g in body weight rapidly decreased from 1 to 6 months and became constant in the later months and levels of both intakes for females were significantly higher than for males after 6 months. Organ indices (g/body weight) of liver and lung in the later months were higher than in the earlier stage, but heart index was constant in all ages. The curve of splenic index showed an exceptional pattern, in which the lowest level appeared at 3 months. Renal index was larger in the male than in the female, but number of glomerulus in renal cortex was significantly greater in the female more than in the male at all ages. Testicular index increased until 3 months and decreased in the later stage, and the percent of seminiferous epithelium was larger at 3 months than at the other ages. Thymic index successively decreased with age; the occupied area of the cortex declined, but conversely the connective tissue and fat increased with thymic involution.

Adipose Tissue↗
PubMed1993

[Concomitant arterial infusion chemotherapy with tamoxifen therapy for hepatic metastases from pancreatic adenocarcinoma--a preliminary report].

The prognosis for hepatic metastasis from pancreatic adenocarcinoma is generally poor. Estrogen receptors have recently been demonstrated in pancreatic adenocarcinoma, and it has been suggested that tamoxifen increases patient survival. We have tried tamoxifen therapy combined with intermittent intraarterial infusion chemotherapy using mainly 5-FU for 4 patients with hepatic metastasis from pancreatic adenocarcinoma. Clinical evaluation of initial response was available for these 4 patients. Although the number of the patients in this study was small, we obtained a response rate of 50%; CR in one case, PR in one case. No patients showed progressive disease (PD). Median survival period was 4.6 months; 3 of 4 patients died with carcinomatous peritonitis at 2.5 to 6 months from the initiation of the therapy. No severe complication was observed. It is believed that this new concomitant therapy is effective in controlling hepatic metastasis from pancreatic adenocarcinoma. But additional therapy for carcinomatous peritonitis, which often develops after achieving hepatic control, is necessary to achieve long-term survival benefit.

Adenocarcinoma↗
PubMed1993

[FDG-PET in an amnestic and hypersomnic patient with bilateral paramedian thalamic infarction].

A 67-year-old patient was admitted to our hospital owing to coma and tetraplegia. MRI showed T2 weighed high intensity areas in the pontine tegmentum, lower aspect of the right cerebellar hemisphere, left half of medulla oblongata, and bilateral paramedian thalamus. He showed marked recovery by urokinase injection becoming able to walk in a few months, but severe amnesia and hypersomnia persisted even 5 months after onset. EEG showed diffuse alpha activity with occasional delta waves in frontal leads. Intelligence was considered normal (WAIS score; verbal IQ 97, performance IQ 102, total IQ 99), through performance on Wechsler memory Scale-R (Revised Japanese edition, WMS-R) and Benton Visual Retention Test indicated impairment of both verbal and visual memory. Verbal memory was impaired to a greater degree than visual memory (Scores of WMS-R: verbal memory index 60, visual memory index 98, index of general memory 72, attention index 95, index of delayed memory 71). He was able to finish only 0 and 1 categories on two trials of the Wisconsin Card Sorting Test. FDG (18F-fluorodeoxyglucose)-PET showed diffuse areas of decreased metabolism in bilateral thalami, frontal lobes, cingulate gyri and medial temporal lobes. The bilateral thalamic lesion seemed to affect the following structures, as judged from MRI: 1) The anterior thalamic peduncle including most of the reciprocal connections between dorsomedial nucleus of thalamus (MD nucleus) and the frontal lobe, 2) The inferior thalamic peduncle which serves as the reciprocal pathway between MD nucleus and medial temporal lobe, especially the amygdala (component of Yakovlev circuit), and 3) The inferior part of mammillothalamic tract (component of Papez circuit).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

[A case report of graft replacement of the ascending and transverse aorta without homologous red blood cell transfusion].

A 28-year-old man of DeBakey type I dissecting aneurysm was received graft replacement of the ascending and transverse aorta under the deep hypothermic circulatory arrest and continuous retrograde cerebral perfusion for cerebral protection during circulatory arrest. From 3 weeks before operation, autologous blood was collected from the patient with the intravenous administration of a recombinant human erythropoietin (rHuEPO) and was subsequently used in the operation. As result, the graft replacement of the ascending and transverse aorta was performed without homologous red blood cell transfusion and postoperative neurological complications. We believe autologous blood transfusion with rHuEPO and circulatory arrest with CRCP contributes operations of aortic aneurysms without homologous blood transfusion.

Adult↗
PubMed1993

[Cardiac hemangioma of the interventricular septum and right ventricle: a case report].

A 52-year-old man who had been pointed out cardiac tumor on echocardiography, CT, MRI and coronary angiography was admitted to our hospital. He was asymptomatic. The surgical excision of the tumor was performed under extracorporal circulation and the postoperative period was free of event. It was not certain whether it originated from interventricular septum or right ventricle. The histology was mixed hemangioma composed of capillary and cavernous type.

Heart Neoplasms↗
PubMed1993

[A case of mesangioproliferative glomerulonephritis (GN) associated with unique lesions of juxtaglomerular apparatus (JGA) and interstitium].

A case of mesangioproliferative glomerulonephritis (GN) associated with unique lesions of the juxtaglomerular apparatus (JGA) and interstitium is discussed. A 31-year-old Japanese woman who developed eyelid and pretibial edema with nephrotic-range proteinuria (4.8 g/day) and without hematuria, was admitted. Her proteinuria and edema quickly disappeared within 7 days after admission without treatment. Her blood examinations revealed hypocomplementemia on admission, but complement recovered to normal levels after 4 weeks. A renal biopsy specimen obtained on the 5th day of admission revealed moderate mesangioproliferative GN with marked periarteriolar inflammatory cell infiltrations in the JGA and occasionally in the tubular interstitium. Depositions of IgG, IgA, IgM and C3 were observed in the glomerular mesangial regions and some capillary walls, but not in the extraglomerular areas. Titers of GN-related viral antigens were not increased. Although the renal histology of this case was similar to that of experimental acute cytomegalovirus (CMV) GN in mice (described by Smith, R.D.), we could not detect CMV antigen by indirect immunofluorescent method or the virus-like particles by electron microscopy. Clinical cases of nephropathy combining lesions of the glomerulus, JGA, and interstitium are very rare. We herein report a patient with mesangioproliferative GN, who underwent an acute clinical course associated with unique inflammatory lesions of the JGA and/or interstitium.

Adult↗
PubMed1992

Auditory working and reference memory can be tested in a single situation of stimuli for the rat.

The comparison of working and reference memory is one of the most valuable research angles for revealing the precise neural mechanisms of memory. The present study introduces a method to test both auditory working and reference memory during a short period in the rat. The apparatus and stimuli are identical for both memory tasks. High and low tones, between which lies a 5-s interval, are continuously presented. The task for working memory is a continuous nonmatching-to-sample. The rat makes go and no-go responses to indicate whether the current tone is the same as (match) or different from (nonmatch) the preceding tone. The task for reference memory is a continuous discrimination. The rat makes go responses on high-tone trials and no-go responses on low-tone trials. With alternate training in these tasks, the rat comes to perform well in both tasks. The rat can only know which task is employed in a given session from its own response-reward contingency during the early trials of each session.

Animals↗
PubMed1992

Suppressive effect of acupuncture on delayed type hypersensitivity to trinitrochlorobenzene and involvement of opiate receptors.

We reported previously that electroacupuncture (Acu) at an acu-point equivalent to GV-4 in mice either enhanced or suppressed the delayed type hypersensitivity (DTH) to 2,4,6-trinitrochlorobenzene (TNCB, picryl chloride) depending on the time of treatment. We report here the suppression of the efferent phase of DTH to TNCB by Acu in mice. In 7- to 9-week-old male BALB/c, C57BL/6 and ddY mice, significant suppression of the DTH was observed when Acu had been applied once per day for three consecutive days before TNCB challenge. When Acu had been applied a single, significant suppression also occurred. Application to another point (at a middle area of the femoral muscle) failed to suppress the DTH to TNCB. This Acu-evoked DTH suppression was blocked dose-relatedly by pretreatment of systemic naloxone hydrochloride, indicating that opioid receptor-mediated mechanisms are involved in this immune response.

Animals↗
PubMed1992

Comparison of constant infusion and flooding dose techniques to measure muscle protein synthesis rate in dogs.

The exact relationship between the constant infusion and flooding dose techniques for measuring fractional muscle protein synthesis (FMPS) rates was determined in anesthetized dogs during the postabsorptive period, using different isotopes of leucine as tracers. First, [1,2-13C]- and [U-14C]leucine were given simultaneously by prime-constant infusion for 5 h to establish that both isotopes gave comparable FMPS rate values. The tracers gave almost identical FMPS rates and the values obtained after 3 and 5 h were not different. Next, the constant infusion and flooding dose methods were compared in the same animal by first measuring FMPS rate with a prime-constant infusion of [U-14C]leucine, then with a flooding dose of 376 mumol/kg [1,2-13C]leucine. The flooding dose method gave FMPS rates that were markedly greater than the constant infusion values. Finally, the effect of a 376 mumol/kg leucine flooding dose on FMPS rate was assessed using the prime-constant infusion of [U-14C]lysine. The large dose of leucine decreased FMPS rate by approximately 50% because acid-soluble muscle lysine (precursor) specific activity increased while the rate of incorporation of labeled lysine into protein decreased. These results indicate that the flooding dose method gives FMPS rates that are markedly greater than those obtained with the constant infusion method and that the latter method is not valid when a large dose of leucine is given.

Animals↗
PubMed1992

Kanji word reading process analysed by positron emission tomography.

Positron emission tomography, involving the H2(15)O injection technique, was used to study changes in regional cerebral blood flow during Japanese kanji word reading. Three-times intrasubject averaging analysis revealed that the main cortical responses occurred in the bilateral (left-side dominant) posterior inferior temporal area for visual input. We believe the left posterior inferior temporal area processes highly complex morphological features of kanji. For language output, left-side dominant activation of the posterior inferior frontal gyrus and the basal ganglia was found.

Adult↗