Biomedical subjects

A Yabuki

Publications and source records attributed to A Yabuki.

At least 19 recordsLinked to original sources

PubMed2003

Renal lesions in spontaneous insulin-dependent diabetes mellitus in the nonobese diabetic mouse: acute phase of diabetes.

The nonobese diabetic mouse is a model of spontaneous insulin-dependent diabetes mellitus. The present study made longitudinal observations of renal lesions in the acute-progressive phase of diabetic mice 0, 10, 20, 30, and 40 days after onset of diabetes without insulin therapy. Plasma creatinine and blood urea nitrogen concentrations gradually increased after onset of diabetes. Kidney weight increased and plateaued at day 20. Under electron microscopy the glomeruli demonstrated only mild changes on day 40. In the proximal tubules proliferating cell nuclear antigen-positive nuclei and nuclear divisions were increased on days 10 and 20. On day 40 of diabetes, increased periodic acid-Schiff-positive granules, confirmed as lysosomal dense bodies, increased neuronal nitric oxide synthase (nNOS) positive reaction, and decreased periodic acid-Schiff staining in the brush border were observed in the proximal straight tubules. In the juxtaglomerular apparatus stratified macula densa were decreased with time in diabetes compared with the findings on day 0, and this macula densa positively reacted with nNOS. No changes in renin levels were observed. In addition, apoptotic cells were not detected. In conclusion, this research represents the first thorough characterization of acute changes in nonobese diabetic mouse kidneys. The results demonstrated renal hypertrophy and slight glomerular injury in early stages and structural alteration of the proximal straight tubules at later stages during the acute phase of diabetes. Furthermore, increased nNOS may represent one of the pathogenic factors of diabetic nephropathy.

Animals↗

PubMed2002

Sex- and strain-dependent histological features of the proximal convoluted tubular epithelium of mouse kidney: association with lysosomes containing apolipoprotein B.

In the present study, we performed comparative histological observations of ICR, BALB/c, C57BL/6, C3H/HeN and DBA/2 mice kidneys. Sex and strain differences were observed in the appearance of vacuolar structures of the proximal convoluted tubules (toluidine blue-positive granules in osmium-postfixed epoxy-resin sections). These features were especially remarkable in male DBA/2 mice. The vacuolar structures in male DBA/2 mice showed heterogeneous staining with Sudan B in frozen sections and appeared under an electron microscope as multilammelar giant dense bodies. In addition, these dense bodies showed heterogeneous acid phosphatase reactions. Immunohistochemical analyses of these structures for apolipoprotein B showed strong positive reactions. These results suggested that vacuolar structures in the proximal convoluted tubules, which were remarkable in male DBA/2 mice, were giant lysosomes containing apolipoprotein B.

Acid Phosphatase↗

PubMed2002

Lectin-histochemical and -cytochemical study of periodic acid Schiff-positive lysosome granules as a histological feature of the female mouse kidney.

Renal proximal straight tubules (PST) of the female mouse contain periodic acid Schiff-positive lysosome granules. An excellent example of this is found in the kidneys of female DBA/2Cr mice. In the present study, lectin-histochemistry showed that lectin-positive granules occur in the PST of DBA/2Cr mice. Out of twenty-one lectins studied, the granules bound WGA, s-WGA, LEL, STL, DSL, GSL-II, VVL, RCA-I, ECL, PSA, LCA and PHA-E. Such granules were also observed in the proximal convoluted tubules (PCT). In addition, heterogeneous binding to the SBA or DBA was observed in the PST. Lectin-cytochemistry for s-WGA, STL, VVL, RCA-I, ECL and PSA, showed that: 1) lysosomes bind a higher level of s-WGA or STL than VVL, RCA-I, ECL or PSA; 2) PSA binding is similar in PST and PCT; 3) there are many PCT lysosomes that are negative for s-WGA, STL, VVL, RCA-I, and ECL lectin binding; and 4) s-WGA binding is highly specific to the lysosomes of the PST. Based on the binding specificities of each lectin, it was suggested that the mannose content of PST and PCT lysosomes is similar, and that PST lysosomes have a high level of N-acetylglucosamine, N-acetylgalactosamine, galactose or galactosyl (beta 1, 4) N-acetylglucosamine.

Animals↗

PubMed2001

A human nuclease specific for G4 DNA.

We have identified a human nuclease that specifically cleaves four-stranded DNA stabilized by G quartets (G4 DNA). This nuclease, GQN1 (G quartet nuclease 1), cuts within the single-stranded region 5' of the barrel formed by stacked G quartets. GQN1 does not cleave duplex or single-stranded DNA, Holliday junctions, or G4 RNA. Cleavage depends on DNA structure and not on flanking sequence. Activity is elevated in but not restricted to B cells, making GQN1 a strong candidate for function in immunoglobulin heavy chain class switch recombination. Identification of a mammalian nuclease that specifically cleaves G4 DNA provides further support for the notion that DNA structures stabilized by G quartets form in vivo and function in regulated recombination and genomic evolution.

Base Sequence↗

PubMed2001

Staining pattern of the brush border and detection of cytoplasmic granules in the uriniferous tubules of female DBA/2Cr mouse kidney: comparison among various fixations and stains.

The proximal straight tubules of the female mouse kidney exhibit heavy periodic acid Schiff (PAS) staining in their brush borders and numerous cytoplasmic granules. In the present study, the female DBA/2Cr mouse kidney was examined, using various fixatives (formalin, PFA, PLP, Zamboni's, Bouin, or Carnoy solution) and various staining methods (HE, PAS, alcian blue, periodic acid methenamine-silver (PAM), toluidine blue, azan, or Congo red). Under azan and PAM, the staining pattern of the brush border was similar to that of PAS, and few effects of the fixative were observed. Cytoplasmic granules were clearly detected with PAM as well as PAS. However, these granules were not detected with Carnoy solution. Furthermore, distribution of granules differed between PAS and PAM.

Animals↗

PubMed2001

Effects of estrous cycle on the mouse kidney morphology.

Although mice kidney morphology shows various sexual dimorphisms, the effect of the estrous cycle has not previously been discussed. In this study, we investigated the effects of the estrous cycle on kidney morphology, including renin-positive areas, of female DBA/2 mice. No effects were confirmed in most of the histometrical parameters, however, the percentage of the renal corpuscles in which cuboidal epithelium covered under 50% of the parietal layer was significantly higher during estrus compared to that during anestrus.

Animals↗

PubMed2001

Sex and strain differences in the brush border and PAS-positive granules and giant bodies of the mouse renal S3 segment cells.

We recently demonstrated sexual dimorphism in the S3 segment of the ICR mouse kidney, as differences in periodic acid Schiff (PAS) staining on the brush border and the number and size of PAS-positive granules. However, whether these sex dependent features in the S3 segment of the mouse kidney occur only in the ICR strain or are a general feature also observed in other strains is unclear. In the present study, we examined the renal S3 segment of the ICR, BALB/c, C57BL/6, C3H/He and DBA/2 mice strains, which are commonly used in laboratory experiments. PAS staining of the brush border in females of all strains was more intense than that of males, and PAS-positive granules were detected in all females. In male groups, PAS-positive granules were detected in the DBA/2 strain only, but their number was very few. In addition, PAS-positive giant bodies, larger than the nuclear size, were detected in females except those of the C57BL/6 strain. Histometrical investigation demonstrated apparent strain differences in a number of PAS-positive granules and PAS-positive giant bodies. The ultrastructural and cytochemical investigations suggest that the PAS-positive granules and PAS-positive giant bodies were multilamellar lysosomes. We propose that the present findings are significant for comparative morphology in laboratory animal science.

Animals↗

PubMed1999

Sexual dimorphism of proximal straight tubular cells in mouse kidney.

The proximal straight tubular epithelium of the mouse kidney exhibited sexual dimorphism in conventional paraffin sections stained with periodic acid Schiff (PAS) in our preliminary observation. The purpose of this study was to clarify the sex-dependent structural features in the proximal straight tubular cells of the mouse kidney, and to clarify the effects of sex hormones on this portion of the renal tissue. The mice used in this study were divided into intact, orchiectomized, ovariectomized, testosterone-treated and estradiol-treated groups. The kidneys of these animals were examined by histological, cytological and cytochemical (for acid phosphatase reaction) procedures. In the proximal straight tubular epithelium of intact adult mice, PAS staining of the brush border in females was more intense than that in males. Furthermore, PAS-positive granules were observed in the cytoplasm of females only. Orchiectomy changed the male-specific features to that of the females, and treatment with testosterone induced the male-specific features. Ovariectomy and estradiol treatment showed no effects. Ultrastructurally, PAS-positive granules were observed as electron-dense myelinoid bodies, and these contained acid phosphatase-positive matrix. The present study demonstrated apparent sexual dimorphism and effects of testosterone on PAS staining and PAS-positive granules in the proximal straight tubule cells in normal mice. In addition, the association of PAS-positive granules and lysosomes was suggested by cytological and cytochemical examination.

Acid Phosphatase↗

PubMed1999

Morphometrical analysis of sex and strain differences in the mouse nephron.

In the present study, we investigated the sexual dimorphisms, effects of castration and sex hormone treatment, and strain differences in the morphology of mouse kidney by measuring the percentage of renal corpuscles with cuboidal cells in the parietal layer of the glomerular capsule, the diameter of renal corpuscles and the number of nuclei of epithelial cells in the proximal convoluted tubule. In ICR mice, the percentage of renal corpuscles with cuboidal cells and the diameter of renal corpuscles were larger in males than in females, and the numbers of nuclei were lower in males than in females. All of these parameters became similar to those of intact females by orchiectomy, and restored to levels similar to those in intact males after testosterone treatment to orchiectomized males. On the other hand, ovariectomy and estradiol treatment gave no effects to any of these parameters. Similar sexual dimorphisms were observed in BALB/c, C57BL/6, C3H/He and DBA/2 mice as in ICR mice, although the diameter of renal corpuscles was not significantly different between males and females in BALB/c mice. Strain differences were observed in each of these three parameters among the 5 strains. In conclusion, the present study demonstrated sexual dimorphisms, effects of castration and sex hormone treatment, and strain differences in the morphology of mouse kidney by morphometrical analysis.

Animals↗

PubMed1994

Relationship of cerebral blood flow, cerebral metabolism, and electroencephalography to outcome in acute experimental compression ischemia--barbiturate effects on delayed brain swelling.

Acute compression ischemia was induced in 30 cats by progressive inflation of an epidural balloon, followed by rapid decompression. Changes in intracranial pressure, mean arterial blood pressure, cerebral blood flow (CBF), arteriovenous oxygen difference (AVDO2), cerebral metabolic rate of oxygen (CMRO2), and electroencephalography (EEG) were studied in 13 untreated animals and in seven animals receiving barbiturate. Ten cats with cardiovascular or respiratory problems, or intracranial hematoma were excluded from the study. In untreated animals, six (46%) survived with no brain swelling and were classified as the "no swelling group," and seven (56%) died from fatal brain swelling and were classified as the "delayed swelling group." All animals with barbiturate therapy showed no brain swelling. Serial measurement of CBF, AVDO2, and CMRO2 indicated the existence of postischemic delayed hypoperfusion associated with relative hypermetabolism in untreated animals. Good recovery of CBF and CMRO2 was observed in the "no swelling group," and poor recovery in the "delayed swelling group." The time course of the total fast-wave components on EEG was quite similar to that of CMRO2, and the time course of the "CBF index," which is % fast-wave component of EEG divided by AVDO2, was similar to that of CBF. Barbiturates reduced CMRO2 and fast-wave component during administration, possibly improving the relatively hypermetabolic state, and reduced the mortality rate to 0%. The maximum effects of barbiturate could be expected by administering the drug at the stage of delayed hypoperfusion with relative hypermetabolism, indicated by rapid recovery of the % fast-wave component, high AVDO2, and low CBF index.

Animals↗

PubMed1993

Pathophysiology of brain swelling after acute experimental brain compression and decompression.

Global ischemia was created by controlled expansion of an epidural balloon for 25 minutes in Group A (six cats) and for 5 minutes in Group B (six cats). The alterations of intracranial pressure, arteriovenous oxygen content difference, cerebral metabolic rate of oxygen, cerebral blood flow, and electroencephalogram were observed until brain death or 24 hours' survival with normal intracranial pressure. The animals were then killed for brain histological examination. In four other cats, a 2% solution of Evans blue dye (4 mg/kg) was injected intravenously--immediately after deflation--resulting in 25 minutes of global ischemia. Two other cats received 5 minutes of global ischemia. The cats were killed 1 hour later. Abrupt swelling occurred in Group A, and no swelling was found in Group B. A transient absolute hyperemia was found immediately after deflation in both groups. The cerebral blood flow and cerebral metabolic rate of oxygen decreased markedly with low arteriovenous oxygen content difference and flat electroencephalogram in Group A, compared with gradual recovery of cerebral blood flow and cerebral metabolic rate of oxygen with high arteriovenous oxygen content difference and reappearance of electroencephalogram activity in Group B. The extravasation of Evans blue was observed on the compressed cerebral hemisphere, thalamus, hypothalamus, and brain stem in swelling animals and only on the compressed hemisphere in nonswelling animals. Histologically, the damage and congestive dilation of capillary, degeneration, and necrosis of neuronal and glial cell were found prominently on the hypothalamus and brain stem in the swelling group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1993

[A case report of BWG syndrome in an elderly patient performed with mitral valve replacement 11 years after single CABG].

A 46-year-old female who had undergone single CABG for BWG syndrome 11 years ago was referred to our hospital for paroxysmal atrial fibrillation. The roentgenogram showed slightly cardiomegaly and the enlargement of LA. Ischemic changes of ECG appeared at I, aVL, V5, V6, as inverted T wave, and low voltage R wave at V1-V4, but non Q wave. The thallium-201 emission computed tomogram at exercise revealed poor perfusion at apical region without redistribution pattern. Catheterization showed mitral regurgitation (grade III), big right coronary artery (RCA) arising from aorta, rich collateral to poor left coronary artery (LCA), and bypass graft was obstructed. The proximal end of LCA was closed, and didn't arise from both pulmonary artery and ascending aorta. In this cases, MVR only without re-CABG to LCA was selected and performed. Postoperative course was uneventful. The result of this case suggested that MVR was an effective surgical procedure for MR of BWG syndrome in the adult case and it was better to add CABG to LCA as much as possible if the ischemic region was large.

Coronary Artery Bypass↗

PubMed1993

[Late malfunction of the Björk-Shiley valve prosthesis due to Delrin disc defacement].

A 55-year-old woman eighteen years after mitral valvular replacement with Delrin disc Björk-Shiley valve prosthesis underwent a reoperation of prosthetic valve replacement for the prosthetic malfunction due to disc defacement. The patient suffered from faintness and vertigo at rest. An echocardiographic examination showed a moderate mitral insufficiency with a normal disc movement. Precise examination on the removed prosthesis revealed accelerated defacement of disc margin which made the ring-disc clearance up to 0.35 mm and strut-shaped groove formation on the inlet surface of the disc occluder. These findings suggested a pronouncedly earlier disc wear than predicted by Björk and co-workers. We concluded, therefore, that a patient undergone a valve replacement with Delrin disc Björk-Shiley valve should be examined periodically by echocardiography even though being without any symptoms.

Female↗

PubMed1993

[Blood purification after aorto-coronary bypass grafting for dialysis patients].

Four dialysis patients received aorto-coronary bypass grafting (CABG) at Fukuyama cardiovascular hospital from April 1989 to March 1992. We employed continuous ambulatory peritoneal dialysis (CAPD) in two cases, hemodialysis with extracorporeal ultrafiltration method (ECUM + HD) in one case and hemodiafiltration with continuous veno-venous hemofiltration (CVVHF + HDF) in one case for perioperative management. In each cases, intermittent HD was undergone during 4 days before operation. Intraoperatively, HD was used together with extracorporeal circulation. Blood pressure in the postoperative course changed more frequently in CAPD cases than ECUM + HD or CVVHF + HDF case. Especially, CVVHF + HDF stabilized the movement of circulation and kept balance of serum BUN, Cr after the operation (BUN; 27.2 +/- 6.3, Cr; 5.0 +/- 0.6). We concluded that CVVHF + HDF would be the most favorable method to maintain the fluid balance stably for the uremic patients after CABG.

Adult↗

PubMed1993

[A case report--successful surgical treatment of prosthetic aortic valve detachment with enlargement of sinuses of Valsalva caused by the recurrence of aortitis].

A successful operation on a 49-year-old female with aortitis syndrome associated with prosthetic aortic valve detachment was reported. Aortic valve replacement using SJM 25A had been performed for aortic regurgitation caused by aortitis. Though her C-reactive protein (CRP) was kept between (+/-) and (2+) with prednisolone administered, general fatigue suddenly appeared 4 years after the first operation. The blood sedimentation rate was 65 mm/30 min and CRP was (4+), and the echocardiography showed abnormal movement of the prosthetic valve with perivalvular leakage on admission. Aortography showed the valve detachment and abnormal movement due to enlargement of sinuses of Valsalva, one of which was transformed as a diverticulum and projected into Left ventricular cavity with moderate leakage. After the inflammation was well controlled, she was operated upon. Dilatation of sinuses, perforation of intima around the prosthetic valve were recognized as left ventricular-aortic discontinuity, but ascending aorta was not enlarged. So the prosthetic valve was suspended below coronary ostia with transmural mattress sutures from right atrium. Postoperative course was uneventful. The postoperative aortography revealed only trivial perivalvular leakage without abnormal movement of the valve. This was a rare case of the valve detachment in the aortitis patient.

Aortic Arch Syndromes↗

PubMed1991

AVDO2 and EEG as indicators for treatment of post-traumatic brain swelling--experimental study.

A cat model of compression ischemia using epidural balloon inflation investigated: 1) the relationship between postischemic cerebral blood flow (CBF) and metabolism and brain swelling, 2) the use of arteriovenous oxygen difference (AVDO2) and electroencephalographic (EEG) frequency band analysis for monitoring CBF and cerebral metabolism, and 3) indications for selecting the therapy. Global ischemia was induced by brain compression, followed by rapid decompression, and AVDO2, CBF, cerebral metabolic rate for oxygen, and EEG were monitored. The animals were divided into delayed brain swelling and no swelling groups. The severity of compression ischemia influenced the recovery of CBF and cerebral metabolism. The AVDO2 and EEG reflected the CBF and cerebral metabolism. These parameters are useful in selecting the therapy for focal brain injury.

Animals↗

PubMed1988

In vivo evaluation of a pyridoxylated-hemoglobin-polyoxyethylene conjugate.

A pyridoxylated-hemoglobin-polyoxyethylene conjugate (PHP) was developed from outdated human red cell hemoglobin through chemical modifications. The PHP has a mean molecular weight of approximately 90,000 daltons, with an acceptable P50 of 22 +/- 0.7 mmHg. This report describes exchange transfusion studies (ET) to a final hematocrit of 5 +/- 2% (n = 5) with PHP in mongrel dogs. Hespan (a plasma expander) was used as a control (n = 6). All the animals with PHP tolerated the procedure well and have survived more than 8 months to date. Five out of the six dogs receiving Hespan died within a week (p = 0.004). Reduction of hematological and coagulation parameters occurred following the ET and returned to the normal range by 4 weeks post ET. Serum electrolytes and renal function parameters (urea, creatinine) remained in the normal range. A transient slight increase in the hepatic enzyme SGOT was observed. At 2 weeks post ET open biopsies of major organs showed vacuolized cells in the liver and kidneys. Normal histology was noted at 3 months. The oxygen transporting properties examined showed effective oxygen delivery to the tissues for 6 hours post ET. PHP continued to transport oxygen for up to 48 hours studied post ET. Half-life of PHP in the circulation was 36.3 +/- 3.5 hours. Urinary loss of hemoglobin measured up to 48 hours after ET was 9.4 +/- 1.6% of the injected net hemoglobin. The PHP effectively supported life at lethal levels of anemia and is a physiologically acceptable solution. It has a relatively long intravascular residence time and transports oxygen to the tissue effectively for at least 6 hours.

Animals↗

PubMed1988

A new resuscitation fluid "stabilized hemoglobin" preparation and characteristics.

A new oxygen carrier for use as a blood substitute was prepared and characterized in vitro. Pyridoxylated hemoglobin, which was obtained by the reaction of human hemoglobin with pyridoxal-5-phosphate, was modified by alpha-carboxymethyl, omega-carboxymethoxyl polyoxyethylene (POE) of the molecular weight 3600 daltons. In order to eliminate viruses and nucleic acids possibly contaminated, the hemoglobin solution was purified by ultrafiltration with a membrane of the nominal molecular weight limit 300 Kdaltons. Furthermore POE conjugated pyridoxylated hemoglobin was treated with 20% ethanol to inactivate viruses. A concentration of hemoglobin, which is incorporated in the conjugate, of the final product was fixed at 6% to make normovolemic exchange transfusion possible. In consideration of the stability during transporting and storage, lyophilized product was selected as a final form ("Stabilized Hemoglobin"). "Stabilized hemoglobin" could be stored in a refrigerator over one year within the acceptable methemoglobin increase. (15%) Viscosity of Stabilized Hemoglobin solution was determined at 2.4 centipoise and is almost half of whole blood and therefore this will be useful not only in resuscitation but also in improvement of microcirculation.

Blood Substitutes↗