Biomedical subjects

A Saito

Publications and source records attributed to A Saito.

At least 109 records · Page 6Linked to original sources

PubMed2001

The effect of third eyelid gland removal on the ocular surface of dogs.

To evaluate the effect of third eyelid removal on the ocular surface of dogs, we operated on five young Beagle dogs and observed changes to tear function using the following tests: phenol red thread test (PRT), Schirmer tear test (STT-1), modified Schirmer tear test (STT-2), pH and tear break-up time (BUT). There was a significant decrease (37%) in STT-2 within 2 weeks after the excision and this declined further to 60% at 1 year. The pH value increased after excision. Presurgical pH was 7.17 +/- 0.20 (mean +/- SD), which increased to 7.55 +/- 0.24 in the 14-60 days following removal, and further increased to 7.77 +/- 0.65 at 1 year. The PRT and STT-1 decreased by 26% within 3-7 months compared to pre-excision values, but by 1 year the values recovered to near normal. The BUT pre-excision value was 24.0 +/- 8.1 s, which shortened to 13.5 +/- 4.5 s after 5 months and continued to decrease further during the study. There were no overt visual signs of KCS during the observational period. However, microinjury of the keratoconjunctival epithelium was observed for all operated eyes when vital staining was used at 1 year post surgery. Surgical excision of the third eyelid in Beagle dogs influenced tear quality level and affected the stability of the tear layer, and at 1 year there was evidence of microinjury to the keratoconjunctival epithelium.

Animals↗

PubMed2001

Estimation of lacrimal level and testing methods on normal beagles.

Five methods of testing tears including the Schirmer tear test (STT-1), phenol red thread tear test (PRT) and modified Schirmer tear test (STT-2) were conducted on 44 eyes of 22 normal Beagles, and the tear film break up time (BUT) and lacrimal pH were tested in 32 eyes of 16 normal Beagles. The coefficient of variation of PRT demonstrated a low value (C.V. 12%) [corrected] compared to the value of STT-1 (C.V. 14%) [corrected]. The lacrimal pH showed a more constant value (C.V. 3%). Measurements of STT-2 (C.V. 48%) and BUT (C.V. 34%) varied significantly. The results show the clinical usefulness of the PRT. Mean values (mean +/- SD) of tests were: PRT, 29.3 +/- 3.45 mm/15 s; STT-1, 18.89 +/- 2.62 mm/60 s; STT-2, 9.52 +/- 4.55 mm/60 s; pH, 7.29 +/- 0.22 and BUT, 21.53 +/- 7.42 s.

Animals↗

PubMed2001

Expression of osteopontin in gentamicin-induced acute tubular necrosis and its recovery process.

BACKGROUND: There is controversy regarding the exact localization and roles of osteopontin (OPN), a multipotential chemokine, in renal injury. There is little information on the expression and role of OPN in gentamicin-induced acute tubular necrosis (ATN) and its recovery process. METHODS: A severe ATN model was made using male Wistar rats by injecting gentamicin (150 mg/kg/day) for five days and limiting the provision of water. The expression and localization of OPN mRNA and protein, ED1 as a macrophage marker, proliferating cellular nuclear antigen (PCNA), CD44 as an OPN receptor, megalin as a proximal tubule marker, and their relationships to each other were examined from the early tubular necrotic period to the late recovery period by Northern blotting, in situ hybridization, and double immunohistochemical staining. RESULTS: In the gentamicin group, OPN mRNA and protein were expressed in only the PCNA-positive proliferating cortical distal tubules, not in the necrotic proximal tubules, until day 6 after the first administration, but were found markedly in PCNA-positive regenerative proximal and distal tubules on days 10, 15, and 30. The localization of PCNA-positive cells was almost always accompanied with the up-regulated expression of OPN using quantitative analysis (P < 0.01). CD44 expression was markedly up-regulated in the renal cortical tubular epithelium from days 6 to 30. In the control group, no expression of OPN and CD44 in the cortical area was found throughout the experimental period. CONCLUSIONS: These results suggested that OPN is related to the proliferation and regeneration of tubular epithelial cells after tubular damage.

Animals↗

PubMed2001

Reactive carbonyl compounds related uremic toxicity ("carbonyl stress").

Many studies on uremic toxins have focused on enzymatic biochemistry. Recently, attention has turned to nonenzymatic biochemistry, especially progressive and irreversible modifications of proteins. Two different approaches opened the field of irreversible nonenzymatic modifications of proteins in uremia: the advanced glycation end products (AGEs) derived from the Maillard reaction and the advanced lipoxidation end products (ALEs) derived from lipid peroxidation. They have revealed the accumulation of reactive carbonyl compounds (RCOs) derived from carbohydrates and lipids and the subsequent carbonyl modifications of proteins ("carbonyl stress"). In this article, we describe the causal role of various RCOs and AGEs/ALEs accumulating in uremia, the clinical consequences of carbonyl stress in uremia, and finally, the therapeutic perspectives. We propose carbonyl stress as a new uremic toxicity.

Amyloidosis↗

PubMed2001

Evaluation of water and electrolyte transport of tubular epithelial cells under osmotic and hydraulic pressure for development of bioartificial tubules.

Our aim was to develop bioartificial tubules using tubular epithelial cells and artificial membranes and evaluate the function of water and electrolyte transport by various tubular epithelial cells. The cells were cultivated onto extracellular matrix (ProNectin F) coating polycarbonate membrane. Water transport from the apical to the basolateral site of cells was examined using a modified Ussing chamber module. Water transport under colloidal osmotic pressure on the apical site and hydraulic pressure on the basolateral site were higher in JTC-12, LLC-PK1 cells than in MDCK cells. Water transport under osmotic plus hydraulic pressure was highest in LLC-PK1 cells. We made bioartificial tubules using LLC-PK1 cells and polysulfone hollow fiber cartridges. Water and Na ion transport function was high, and BUN and creatinine passage was recognized in these bioartificial tubules. BUN and creatinine concentrations of reabsorption fluid in these bioartificial tubules were significantly lower than those concentrations of control media and of noncell attached polysulfone hollow fiber cartridges. Though LLC-PK1 cells were more preferable cells for the use of bioartificial tubules in terms of water and electrolyte transport, the passage of BUN and creatinine was not appropriate for clinical use. To select more preferable cells for bioartificial tubules which transport water and electrolytes and do not induce passage of uremic toxins is necessary.

Animals↗

PubMed2001

The estimation of cardiac function from the rotary blood pump.

The rotary blood pump is implanted as a bridge to cardiac transplantation. Mechanical, histological, and biochemical improvements have been described in patients after implantation of left ventricular assist devices (LVADs). Thus, the rotary blood pump might be used as a bridge to recovery of myocardial function. However, unlike a pulsatile pump, the rotary blood pump cannot be stopped to estimate cardiac function: if the rotary blood pump stops, backflow will occur. In this study, a new method that can estimate cardiac function without pump stop was examined. Six pigs were the subjects of this acute study. The pump was implanted as an LVAD: the inlet cannula was inserted into the left ventricle, and the outlet cannula was inserted into the ascending aorta. The motor speed was regulated at a pump flow rate of 0 L/min at diastolic phase. Then, the relationship between the dp/dt of left ventricular pressure and external stroke work of actuator was examined. This method was studied at normal, hyperdynamic, and heart-failure conditions. There was a high positive correlation between the dp/dt of left ventricular pressure and external stroke work of actuator. This method is useful and simple to estimate cardiac function without pump stop.

Animals↗

PubMed2001

Effects of left ventricular assist device on cardiac function: experimental study of relationship between pump flow and left ventricular diastolic function.

The left ventricular assist device (LVAD) with centrifugal pump has two characteristics. One is a pump flow wave of the centrifugal pump, consisting of the pulsatile flow of the native heart and the nonpulsatile flow of the centrifugal pump. The other is that the centrifugal pump fills from the native heart not only in the systolic phase, but also in the diastolic phase. In the case of the apex outlet LVAD with centrifugal pump, blood flows from the left atrium through the left ventricle to the pump. Pump flow is regulated by preload, and preload is regulated by diastolic hemodynamics. The aim of this study is to analyze the relationship between pump flow and the diastolic hemodynamics of the native heart. Ten anesthetized intact pigs were studied after placement of an LVAD. Data were recorded with the LVAD off (control) and the LVAD on. The assist rate was changed to 25%, 50%, and 75%. The indexes of left ventricular (LV) diastolic function included LV myocardial relaxation (time constant of isovolumic pressure decay [Tau] and maximum negative dP/dt [LV dP/dt min]) and LV filling (peak filling rate [PFR], time to peak filling rate [tPFR], and diastolic filling time [DFT]). Stroke volume decreased significantly in 75% assist. LV end-systolic pressure decreased significantly in 50% and 75% assist. LV end-diastolic volume decreased as assist rate increased, but there were no significant changes. Stroke work decreased significantly in 50% and 75% assist. LV dP/dt min decreased significantly in 50% and 75% assist. Tau prolonged as assist rate increased, but there were no significant changes. DFT shortened significantly in 75% assist. PFR increased significantly in 75% assist. tPFR shortened significantly in 50% and 75% assist. In this study, LV relaxation delayed as an increasing of pump assist rate, but it suggested a result of reduction of cardiac work. Also, it was suggested that LVAD increases the pressure difference between the left atrium and the left ventricle in the diastolic phase. This phenomenon is due to the filling of the left ventricle. In this study it was suggested that as pump assist rate increases, it is more effective to keep cardiac function in the diastolic phase.

Animals↗

PubMed2001

Endoscopic recurrence of esophageal varices is associated with the specific EUS abnormalities: severe periesophageal collateral veins and large perforating veins.

BACKGROUND: Endoscopic ultrasonography (EUS) with a 20 MHz ultrasound (US) catheter probe can clearly demonstrate esophageal collateral veins. The presence of large periesophageal collateral veins has been correlated with large esophageal varices in patients with portal hypertension. The correlation between the size of esophageal collateral veins and endoscopic recurrence of esophageal varices in patients with portal hypertension who had undergone endoscopic injection sclerotherapy was investigated. Furthermore, whether EUS findings could predict the variceal recurrence was retrospectively studied. METHODS: Thirty-eight patients who had undergone endoscopic injection sclerotherapy were examined every 3 to 4 months with endoscopy and US catheter probe for a period of 2 years. Recurrence of esophageal varices was determined by endoscopic findings of either new varix formation or appearance of red color sign. Esophageal collateral veins were identified by US catheter probe as peri-esophageal collateral veins (adjacent to the esophageal wall) and para-esophageal collateral veins (separated from the esophageal wall) along with perforating veins; and they were graded as severe and mild type by US catheter probe. RESULT: Ten of the 38 patients (26.3%) had endoscopic recurrence at a mean of 10.9 months after endoscopic injection sclerotherapy. In patients with endoscopic recurrences, EUS findings included a significantly (p < 0.001) higher incidence of severe type peri-esophageal collateral veins, a significantly larger number of perforating veins (p < 0.001) and a significantly larger diameter of perforating veins (p < 0.001) compared with patients without recurrence (8 of 10, 80% vs. 2 of 28, 7.1%; 1.30 vs. 0.21; 2.00 vs. 0.32 mm, respectively). The presence of veins at the esophagogastric junction did not correlate with recurrence. CONCLUSION: Severe type peri-esophageal collateral veins and large perforating veins of the esophagus detected by EUS in patients treated by endoscopic injection sclerotherapy signify recurrence of esophageal varices and predict endoscopic recurrence of varices in subsequent months.

Collateral Circulation↗

PubMed2001

Effects of JPEG and wavelet compression of spiral low-dose ct images on detection of small lung cancers.

PURPOSE: To compare the effect of compression of spiral low-dose CT images by the Joint Photographic Experts Group (JPEG) and wavelet algorithms on detection of small lung cancers. MATERIAL AND METHODS: Low-dose spiral CT images of 104 individuals (52 with peripheral lung cancers smaller than 20 mm and 52 control subjects) were used. The original images were compressed using JPEG or wavelet algorithms at a ratio of 10:1 or 20:1. Five radiologists interpreted these images and evaluated the image quality on a high-resolution CRT monitor. Observer performance was studied by receiver operating characteristic (ROC) analysis. RESULTS: There was no significant difference in the detection of cancers measuring 6 to 15 mm in uncompressed images and in those compressed by either of the algorithms, although the quality of images compressed at 20:1 with the wavelet algorithm was somewhat inferior. A lower diagnostic accuracy was noted using images compressed by the JPEG or wavelet algorithms at 20:1 in detecting lung cancers measuring 6 to 10 mm and cancers measuring from 6 to 15 mm with ground-glass opacity. CONCLUSION: Compression of low-dose CT images at a ratio of 10:1 using JPEG and wavelet algorithms does not compromise the detection rate of small lung cancers.

Algorithms↗

PubMed2001

Detection of occult metastatic lymph nodes in the neck with gray-scale and power Doppler US.

PURPOSE: To determine the most accurate criterion for predicting malignancy of small cervical lymph nodes with gray-scale ultrasound (GSUS) and power Doppler ultrasound (PDUS). MATERIAL AND METHODS: Findings of 69 pathologically verified cervical nodes (38 benign, 31 malignant) in 57 patients without wide echogenic hilum on GSUS that measured less than 10 mm in minimal axial diameter were prospectively studied. Minimal and maximal axial diameters, ratios of minimal to maximal axial diameters, and presence or absence of calcification or necrosis of the nodes were assessed. On PDUS, vascularity in the node was classified into 4 pattern groups. A logistic model was used to evaluate the significant factors for predicting malignancy. RESULTS: The logistic model revealed that the minimal axial diameter and vascularity patterns were the only significant factors for malignancy. Using the minimal axial diameter, a node larger than 8 mm showed the highest accuracy (73%) with 45% sensitivity and 93% specificity. Of the vascularity patterns, spotted or peripheral pattern had the highest accuracy (80%) with 61% sensitivity and 93% specificity. A combined criterion of the minimal axial diameter larger than 8 mm and spotted or peripheral pattern increased the accuracy to 82% and sensitivity to 77% but specificity decreased to 86%. CONCLUSION: A combined criterion of minimal axial diameter and vascular patterns was most accurate for diagnosing occult metastatic lymph nodes in the neck.

Adult↗

PubMed2001

Randomized phase I study of standard-fractionated or accelerated-hyperfractionated radiotherapy with concurrent cisplatin and vindesine for unresectable non-small cell lung cancer: a report of Japan Clinical Oncology Group Study (JCOG 9601).

BACKGROUND: We attempted dose escalation of standard-fractionated and accelerated-hyperfractionated radiotherapy combined with concurrent cisplatin and vindesine to improve local control and survival in unresectable non-small cell lung cancer. METHODS: Twenty-one patients were enrolled between June 1996 and August 1997. There were 19 males and two females and their median age was 65 years (range 45-74 years). Performance status was 0 in 10 cases and 1 in 11 cases. Disease stage was IIIA in three cases and IIIB in 18 cases. The cases were randomized to a standard-fractionated arm (n = 10) or an accelerated-hyperfractionated radiotherapy arm (n = 11) with two or three cycles of concomitant cisplatin 80 mg/m(2) on day 1 and vindesine 3 mg/m(2) on days 1 and 8 every 4 weeks in both arms. Dose escalation from 60 Gy/30 fractions/6 weeks to 70 Gy/35 fractions/7 weeks was planned in the standard-fractionated radiotherapy group and from 54 Gy/36 fractions/3.6 weeks to 60 Gy/40 fractions/4 weeks and then 66 Gy/44 fractions/4.4 weeks in the accelerated-hyperfractionated radiotherapy group. RESULTS: Grade 3 or 4 hematological toxicities were observed as follows: in the standard-fractionated/accelerated-hyperfractionated radiotherapy group, leukocytopenia 9/10, anemia 2/3 and thrombocytopenia 0/2. Grade 3 non-hematological toxicity consisted of esophagitis 0/3, increased serum total bilirubin 2/0 and hypoxia 0/1. Two patients died of radiation pneumonitis in the standard-fractionated radiotherapy group. Dose-limiting toxicity was observed in four of the 10 and seven of the 11 patients at initial dose level of standard-fractionated radiotherapy, 60 Gy/30 fractions/6 weeks, and of accelerated-hyperfractionated radiotherapy, 54 Gy/36 fractions/3.6 weeks, respectively. Thus, we failed to escalate the dose of radiotherapy in both arms. The overall response rate in the standard-fractionated group and the accelerated-hyperfractionated radiotherapy group was 70 and 73% and the 1-year survival rate was 70 and 64%, respectively. CONCLUSIONS: We concluded that these schedules of radiotherapy with concurrent cisplatin and vindesine were unacceptable for use in patients with unresectable non-small cell lung cancer. Further modifications of the schedule for radiotherapy and evaluation of combination with new chemotherapy are warranted.

Aged↗

PubMed2001

Advanced glycation and lipoxidation end products: reactive carbonyl compounds-related uraemic toxicity.

Most studies on uraemic toxins have focused on disorders of enzymatic biochemistry. Recent studies to elucidate the pathogenesis of dialysis-related amyloidosis have provided new insights in progressive, irreversible protein modifications resulting from non-enzymatic biochemistry in uraemia. This paper focuses on two types of irreversible alterations of proteins: advanced glycation and lipoxidation. We investigate the causal role of various reactive carbonyl compounds (RCOs) accumulating in the serum, speculate on its clinical consequences, and discuss the therapeutic perspectives.

Animals↗

PubMed2001

Effects of calnexin deletion in Saccharomyces cerevisiae on the secretion of glycosylated lysozymes.

Disruption of the calnexin gene in Saccharomyces cerevisiae did not lead to gross effects on the levels of cell growth and secretion of wild-type hen egg white lysozymes (HEWL). To investigate the function of calnexin in relation to the secretion of glycoproteins, we expressed both stable and unstable mutant glycosylated lysozymes in calnexin-disrupted S. cerevisiae. The secreted amounts of stable mutant glycosylated lysozymes (G49N and S91T/G49N) were almost the same in both wild-type and calnexin-disrupted S. cerevisiae. In contrast, the secretion of unstable mutant glycosylated lysozymes (K13D/G49N, C76A/G49N, and D66H/G49N) greatly increased in calnexin-disrupted S. cerevisiae, although their secretion was very low in the wild-type strain. This indicates that calnexin may act in the quality control of glycoproteins. We further investigated the expression level of the mRNA of the molecular chaperones BiP and PDI, which play a major role in the protein folding process in the ER, when glycosylated lysozymes were expressed in wild-type and calnexin-disrupted S. cerevisiae. The mRNA concentrations of BiP and PDI were evidently increased when the glycosylated lysozymes were expressed in calnexin-disrupted S. cerevisiae. This observation indicates that BiP and PDI may be induced by the accumulation of unfolded glycosylated lysozymes due to the deletion of calnexin.

Calcium-Binding Proteins↗

PubMed2001

The Purple leaf (Pl) locus of rice: the Pl(w) allele has a complex organization and includes two genes encoding basic helix-loop-helix proteins involved in anthocyanin biosynthesis.

The Purple leaf (Pl) locus of rice (Oryza sativa L.) affects regulation of anthocyanin biosynthesis in various plant tissues. The tissue-specific patterns of anthocyanin pigmentation, together with the syntenic relationship, indicate that the rice Pl locus may play a role in the anthocyanin pathway similar to the maize R/B loci. We isolated two cDNAs showing significant identity to the basic helix-loop-helix (bHLH) proteins found in the maize R gene family. OSB1 appeared to be allelic to the previously isolated R homologue, Ra1, but showed a striking difference at the C-terminus because of a 2-bp deletion. Characterization of the corresponding genomic region revealed that the sequence identical to a 5'-portion of OSB2 existed approximately 10-kb downstream of the OSB1 coding region. OSB2 lacks a conserved C-terminal domain. Restriction fragment length polymorphism analyses using an F(2) population indicate that both genes co-segregate with the purple leaf phenotype. A transient complementation assay showed that the anthocyanin pathway is inducible by OSB1 or OSB2. These results suggest that the Pl(w) allele may be complex and composed of at least two genes encoding bHLH proteins.

Alleles↗

PubMed2001

[A case of loiasis].

Loiasis is quite common in the endemic regions of Central and West Africa. But only three cases were reported in Japan. This is a report of a 28 year old male from Gabon infected with Loa loa with eye symptoms as the chief complaint. For the first time in Japan he was treated with Ivermectin (IVM) which is recently attracting attention as the drug for filariasis world wide. IVM therapy was effective, and decreased the counts of microfilarias in the patient's blood. No adverse effect was seen in this patient. This case suggested that IVM is an useful drug for loiasis, and further study is warranted.

Adult↗

PubMed2001

[Clinical and bacteriological features of 12 cases of liver abscess caused by Streptococcus milleri group].

We described the clinical and bacteriological features of 12 cases of liver abscess caused by Streptococcus milleri group (SMG) during a 6-year period from 1993 to 1998. The gender was 11 males and 1 female with their ages ranging from 39 to 76 years old (mean: 53.4). The common symptoms were fever (100%), abdominal pain (67%), and appetite loss (58%). Nine cases had underlying diseases such as carcinomas and diabetes mellitus. Predominant causes of the liver abscess were cryptogenic (42%) and biliary tract disease (33%). Three patients died of an exacerbation of the carcinoma. Eight cases (67%) was single infection of SMG and no mixed infection with anaerobes. No strains isolated in this series showed resistance against penicillin G and ampicillin. SMG was highly isolated from the blood culture in eight of the 11 cases (73%). Liver abscess should be taken into consideration as one of the causes of SMG septicemia.

Adult↗

PubMed2001

Characteristics of a Streptomyces coelicolor A3(2) extracellular protein targeting chitin and chitosan.

Upstream of the Streptomyces coelicolor A3(2) chitinase G gene, a small gene (named chb3) is located whose deduced product shares 37% identical amino acids with the previously described CHB1 protein from Streptomyces olivaceoviridis. The chb3 gene and its upstream region were cloned in a multicopy vector and transformed into the plasmid-free Streptomyces lividans TK21 strain. The CHB3 protein (14.9 kDa) was secreted by the S. lividans TK21 transformant during growth in the presence of glucose, N-acetylglucosamine, yeast extract, and chitin. The protein was purified to homogeneity using anionic exchange, hydrophobic interaction chromatographies, and gel filtration. In contrast to CHB1, CHB3 targets alpha-chitin, beta-chitin, and chitosan at pH 6.0 but does so relatively loosely. The ecological implications of the divergence of substrate specificity of various types of chitin-binding proteins are described.

Amino Acid Sequence↗

PubMed2001

Activation of Valpha14(+) natural killer T cells by alpha-galactosylceramide results in development of Th1 response and local host resistance in mice infected with Cryptococcus neoformans.

We examined the effect of alpha-galactosylceramide (alpha-GalCer) on the synthesis of gamma interferon (IFN-gamma) and local resistance in mice infected intravenously with Cryptococcus neoformans. The level of IFN-gamma in serum increased on day 3, reached a peak level on day 7, and decreased to the basal level on day 14 postinfection in mice treated with alpha-GalCer, while in vehicle-treated mice, no increase was detected at any time points except for a small increase on day 7. Such effects were not observed in NKT-KO mice. In CD4KO mice, minor synthesis of IFN-gamma was detected on day 3 in sera but was completely abolished by day 7. The alpha-GalCer-induced IFN-gamma production on day 3 was partially reduced in mice depleted of NK cells by treatment with anti-asialo-GM(1) antibody (Ab). Spleen cells obtained from infected and alpha-GalCer-treated mice on day 7 produced a large amount of IFN-gamma upon restimulation with live organisms, while only a marginal level of production was detected in splenocytes from infected and vehicle-treated mice. Such effects were abolished in CD4KO and NKT-KO mice. Finally, the fungal loads in the lungs and spleen on days 7 and 14 were significantly reduced in alpha-GalCer-treated mice compared to those in control mice. In NKT-KO mice, local resistance elicited by alpha-GalCer was completely abolished, although no obvious exacerbation of infection was detected. Furthermore, treatment with anti-IFN-gamma monoclonal Ab mostly abrogated the protective effect of this agent. Thus, our results indicated that activation of Valpha14(+) NKT cells resulted in an increased Th1 response and local resistance to C. neoformans through production of IFN-gamma.

Animals↗