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Biomedical subjects

O Sakai

Publications and source records attributed to O Sakai.

At least 37 records · Page 2Linked to original sources

Identification of two mutations in human xanthine dehydrogenase gene responsible for classical type I xanthinuria.

Hereditary xanthinuria is classified into three categories. Classical xanthinuria type I lacks only xanthine dehydrogenase activity, while type II and molybdenum cofactor deficiency also lack one or two additional enzyme activities. In the present study, we examined four individuals with classical xanthinuria to discover the cause of the enzyme deficiency at the molecular level. One subject had a C to T base substitution at nucleotide 682 that should cause a CGA (Arg) to TGA (Ter) nonsense substitution at codon 228. The duodenal mucosa from the subject had no xanthine dehydrogenase protein while the mRNA level was not reduced. The two subjects who were siblings with type I xanthinuria were homozygous concerning this mutation, while another subject was found to contain the same mutation in a heterozygous state. The last subject who was also with type I xanthinuria had a deletion of C at nucleotide 2567 in cDNA that should generate a termination codon from nucleotide 2783. This subject was homozygous for the mutation and the level of mRNA in the duodenal mucosa from the subject was not reduced. Thus, in three subjects with type I xanthinuria, the primary genetic defects were confirmed to be in the xanthine dehydrogenase gene.

Adult↗

Rapid identification and typing of Staphylococcus aureus by nested PCR amplified ribosomal DNA spacer region.

We designed a polymerase chain reaction (PCR) assay for rapid detection of prokaryotic 16S-23S spacer regions. This PCR assay consisted of nested DNA amplifications. The first-step PCR was able to detect the general presence of eubacteriales with a unified set of universal primers. The universal primers were selected from highly conserved regions in 16S and 23S ribosomal RNA (rRNA) genes and amplified DNAs from all 62 different species of bacteria tested. In the second-step PCR, the identification primers could detect four important bacterial species through amplification of the rRNA spacer regions between the 16S-23S rRNA genes. For Staphylococcus aureus, intraspecies variation in spacer amplification products was observed with S. aureus specific primers. We suggest that the nested PCR assay could be used as a novel method for the identification and typing in epidemiological studies of S. aureus.

DNA Primers↗

Asymmetrical or heterogeneous enhancement of the internal jugular veins in contrast-enhanced CT of the head and neck.

With faster CT scanners, asymmetric/heterogeneous enhancement (ASHE) of the internal jugular veins (IJVs) is frequently encountered in the absence of pathology. We investigated the frequency, side, pattern and significance of ASHE in 200 patients with various head and neck lesions. Non-ionic contrast medium (300 mgI/ml) was infused into a forearm vein (right, n = 100); left, n = 100). Forty seconds after contrast medium injection, contiguous 5-mm-thick sections were obtained craniocaudally from the skull base to the aortic arch. CT machines with two different scanning cycle times (3 s, n = 100; 2 s, n = 100) were used. ASHE of the IJVs was observed in 51 patients (25.5%); the patient group receiving a right-sided injection with a 2-s scan cycle machine, showing a higher frequency (44%). ASHE was divided into four patterns: homogeneous low density, focal low density, heterogenous opacification and fluid-fluid level formation. ASHE was frequently observed in routine contrast-enhanced CT of the head and neck. Frequency of ASHE increased when the scanning cycle was shorter. We should be aware of this phenomenon to avoid its misinterpretation as venous thrombosis or other pathology.

Adolescent↗

Immunohistochemical detection of advanced glycosylation end-products in the peritoneum and its possible pathophysiological role in CAPD.

It has recently been suggested that advanced glycosylation end-products (AGEs) are formed in the peritoneum in patients on CAPD. However, the exact location of AGE accumulation, the relation with the duration of CAPD and its pathophysiological role in CAPD remain unclear. If the peritoneum is glycosylated, it could bring about altered peritoneal function. Therefore, the aim of this study is to clarify the localization of AGEs in the peritoneum in accordance with the duration of CAPD and to examine its relation to the peritoneal permeability. Fifteen non-diabetic patients were divided into three groups (each 5 patients) on the basis of the mean duration (D) of CAPD (Group 1, D = 0 month; Group II, D = 34 months; Group III, D = 84 months). The AGE staining by monoclonal anti-AGE antibody in the peritoneum and the four-hour peritoneal equilibration test (PET) were compared among these groups. AGE was absent or found only weakly in Group I. However, in groups II and III, AGE was moderately or strongly positive especially in the vascular walls and it was dominant in group III. PET revealed that peritoneal permeability for glucose, creatinine, beta2-microglobulin and albumin was increased in Group II as compared to Group I, and it was further increased in Group III. The results of this study indicate that AGEs become dominantly accumulated in the vascular wall in accordance with the prolongation of CAPD treatment, and this might play some roles for the increased permeability of the peritoneal membrane in CAPD.

Adult↗

Longitudinal changes of metacarpal cortical striation in Graves' disease.

RATIONALE AND OBJECTIVES: The authors verify whether metacarpal cortical striation can be used to assess longitudinal changes in bone turnover in Graves' disease. METHODS: Eight patients with untreated Graves' disease (5 men, 3 women; age 36 +/- 12 years) and six patients with the disease in remission (1 man, 5 women; age 38 +/- 12) were studied. Posteroanterior radiographs of the bilateral hands were obtained using fine-grain mammography film and direct magnification. Three observers independently determined the grade of cortical striation (striation index; SI) of the second and third metacarpals in randomly presented radiographs. RESULTS: The SI determined by all observers decreased significantly after the beginning of antihyperthyroid therapy compared with the SI before treatment (P < 0.05). Significant correlation was found between the observers' assessments (r = 0.74, P < 0.001). The average kappa value and percent agreement were 0.27 and 51.8%, respectively. Intraobserver variability provided relatively good kappa statistics (kappa: 0.56; percent agreement: 79.9%). Longitudinal decrease in the SI was in accordance with a decline in urinary pyridinoline cross-link excretion, a decline in serum osteocalcin, and an increase in bone mineral density of lumbar spine. CONCLUSIONS: The change in the SI can be used to detect increased and decreased bone turnover. Thus, the SI can be used as one index of bone turnover in patients with Graves' disease.

Absorptiometry, Photon↗

Simultaneous detection of Streptococcus pneumoniae and Haemophilus influenzae by nested PCR amplification from cerebrospinal fluid samples.

Haemophilus influenzae and Streptococcus pneumoniae are often the cause of serious diseases such as meningitis. We designed a nested PCR assay to identify these pathogens from cerebrospinal fluid samples. The first-step PCR was able to detect eubacterial rRNA genes with a unified set of universal primers. In the second-step PCR, the identification primers, HI I and II and SP I and II, could detect H. influenzae and S. pneumoniae respectively through amplification of the rRNA spacer between the 16S and 23S rRNA genes. We suggest that the two-step PCR assay can be used as a novel method for the immediate and retrospective diagnosis of bacterial meningitis caused by H. influenzae and S. pneumoniae.

Cerebrospinal Fluid↗

A case of renal amyloidosis associated with hepatic adenoma: the pathogenetic role of tumor necrosis factor-alpha.

We report a case of a 35-year-old man with secondary amyloidosis chiefly involving the kidney and heart. The patient showed severe proteinuria and ischemic heart damage and had hepatic adenoma at the age of 33. Biopsy specimens from the kidney, heart, stomach and rectum showed extensive deposition of amyloid. After the surgical resection of a 300-gram hepatic adenoma, highly elevated c-reactive protein (CRP) levels decreased and the serum amyloid A (SAA) level was completely normalized. Normal liver cells were immunostained with rabbit anti-SAA antibody, but the cells in adenoma tissue and kidney were not. Electron microscopic examination revealed extracellular deposition of amyloid fibrils in the hepatic adenoma and kidney tissue. The concentration of tumor necrosis factor-alpha (TNF-alpha) (312 pg/mg tissue protein) was 7-fold higher in adenoma tissue than in normal liver tissue. Moreover, SAA (2.8 ng/mg tissue protein) was 2-fold higher in normal liver tissue than in adenoma tissue. Since TNF-alpha has been known to induce SAA production in target cells, the present results suggest that the hepatic adenoma produced TNF-alpha, which then caused mainly secondary amyloidosis in the kidney and heart. Currently, 2 years after surgical resection, urinary excretion of protein has been markedly reduced (from 3.5 to 0.8 g/day) and renal and cardiac functions are normal without specific medical treatment.

Adenoma↗

Reversal of anemia by erythropoietin therapy retards the progression of chronic renal failure, especially in nondiabetic patients.

Therapy with human recombinant erythropoietin (EPO) has been accepted as effective for renal anemia in dialysis patients. However, studies in rats have shown that correcting anemia with EPO may affect the progression of renal dysfunction. In humans, however, the effect of EPO on residual renal function is a matter of controversy. We, therefore, investigated whether the long-term administration of EPO to predialysis patients influences residual renal function. Anemic patients at the predialysis stage with a serum creatinine (Cr) concentration ranging from 2 to 4 (average 2.9) mg/dl and a hematocrit (Ht) of less than 30% were randomly assigned to two groups which consisted of anemic patients not treated with EPO (group I, untreated anemic controls, n = 31) and anemic patients treated with EPO (group II, treated anemics, n = 42). Patients with nonsevere or moderate anemia (Ht > 30%) with a Cr ranging from 2 to 4 (average 2.6) mg/dl were also recruited as nonanemic controls (group III, untreated nonanemic controls, n = 35). Blood pressure was controlled to the same degree among the three groups by combined treatment with calcium antagonists and angiotensin-converting enzyme inhibitors. All patients were kept strictly on a low-protein (0.6 g/kg/day) and a low-salt (7 g/day) diet. The degree of control of dietary protein and blood pressure and the frequency of angiotensin-converting enzyme inhibitor administration were comparable among the three groups. The primary end point for each patient was a doubling of the baseline Cr which yielded cumulative renal survival rates which were plotted against time. Ht rose significantly from 27.0+/-2.3 to 32.1+/-3.2% in group II (n = 42, p < 0.001) with a rate of increase of 0.4+/-0.06%/week. However, it declined from 27.9+/-1.8 to 25.3+/-1.9% in group I (n = 31, p < 0.001) and from 35.9+/-3.5 to 32.2+/-3.9% in group III (n = 35, p < 0.001). Cr doubled in 26 patients (84%) in group I as compared with 22 (52%) in group II and 21 (60%) in group III. The cumulative renal survival rates in groups II and III were significantly better than that in group I: p = 0.0003 (group I vs. group II) and p = 0.0024 (group I vs. group III). However, there was no difference in the renal survival rate between groups II and III (p = 0.3111). The better survival rate obtained in group II was attributable to the better survival rate for the nondiabetic patients in this group. The present study suggests that anemia, per se, is a factor in the progression of end-stage renal failure and that reversal of anemia by EPO can retard the progression of renal failure, especially in nondiabetic patients, provided that blood pressure control, rate of increase in Ht, and dietary protein restriction are appropriate.

Adult↗

Identification of essential ionizable groups in active site of Aspergillus niger alpha-glucosidase.

A kinetic study was done to identify the ionizable groups in the active site of Aspergillus niger alpha-glucosidase (ANGase). From dependence of V and Km values on pH, we obtained the ionization constants of essential ionizable groups 1 and 2 of free enzyme; pKe1 = 3.2 and pKe2 = 6.4. When the dielectric constant of the reaction mixture was decreased, the pKe1 and pKe2 were shifted to higher values. The ionization heats (delta H's) of ionizable groups 1 and 2 were measured to be -0.4 kcal/mol and 0 kcal/mol, respectively. The water-soluble carbodiimide (WSC), a specific reagent for carboxyl groups, inactivated the enzyme activity completely, and maltose as substrate decreased the inactivation. The WSC did not modify the free Cys. These findings suggest that the essential ionizable groups of ANGase are two kinds of carboxyl groups: one is a charged type (-COO-, ionizable group 1), and the other is a protonated type (-COOH, ionizable group 2).

Aspergillus niger↗

Acute renal failure after binge drinking of alcohol and nonsteroidal antiinflammatory drug ingestion.

A case of reversible acute renal failure (ARF) following binge drinking together with the transient use of a nonsteroidal antiinflammatory drug (NSAID) is described. After binge drinking. the patient experienced hyperdipsia, and the volume of his urine decreased. Subsequently, he took an NSAID to relieve systemic joint pain associated with low grade fever, and then he had complete anuria. One day after taking the NSAID, he visited our hospital, and was found to have severe renal dysfunction accompanied by severe liver damage (blood urea nitrogen and creatinine concentrations were 57 and 5.4 mg/dl, respectively). The impaired renal function progressed over the first three hospital days, as reflected by an elevated creatinine concentration to 11.6 mg/dl. Nine treatment sessions of hemodialysis were, therefore, required to recover the loss of renal function. The present case suggests that binge drinking may be a potential risk factor for ARF in the presence of NSAIDs.

Acute Kidney Injury↗

Aminoglycoside-induced viability in cultured PtK1 proximal tubular cell lines.

The cell viability after aminoglycoside administration was evaluated by the determination of adenosine triphosphate (ATP) level and trypan blue exclusion of cultured PtK1 tubular cells. The assay in tubular cells was performed using luciferin-luciferase determined by a chemiluminator. The data are expressed as relative light units per milligram tissue protein. The standard curve of ATP showed a linearity from 0.5 to 2.5 mg/ml ATP as determined by the chemiluminator. The incubation time was steady for ATP production during 90 min after addition of ligand. The optimal incubation time was 60 min. The ATP production in PtK1 cells showed linearity within 10(3) to 5 x 10(6) cells in 200 microliters buffer. Although the magnitude of ATP production in Ptk1 cells was correlated with the cell viability as defined by trypan blue exclusion, the reproducibility of the former was better than that of the latter. The cell viability after application of aminoglycoside showed a decrement in a dose-dependent fashion. Our ATP assay is an excellent tool for determining the cell viability of renal proximal tubules in cases with tubular damage after administration of aminoglycoside antibiotics.

Adenosine Triphosphate↗

[Improvement of longitudinal resolution by deblurring technique in helical CT of the head and neck].

We assessed the improvement of longitudinal resolution in helical CT by deblurring techniques in a phantom and 8 head and neck patients. After helical scanning with 3- or 5-mm-collimation and 3- or 5 mm/sec table feed, overlapped axial images were reconstructed at every 0.3 or 0.5 mm pitch. Deblurring techniques were applied to these data. The slice profile and longitudinal resolution were improved by deblurring. Longitudinal resolution increased with the strength of deblurring. Image sharpness was improved in reconstructed images of MPR, MIP and 3D, and better visualization of the peripheral vessels was obtained in CTAs.

Head and Neck Neoplasms↗

[Evaluation of changes in destructive spondylarthropathy (DSA) in long-term dialysis patients].

This study was undertaken to evaluate destructive spondylarthropathy (DSA) in patients long-term dialysis. The patients were investigated by plain X-ray examinations twice with a three-year interval, and the changes in severity of the illness in 66 patients undergoing dialysis for over 5 years were defined. Group A (9 patients) consisted of patients with progression in grades during the three years, while group B (57 patients) consisted of patients without deterioration. There was no differences in the two groups in age, duration and the modality of dialysis. However, in group A, the level of plasma beta 2-microglobulin (beta 2M) was 33.5 +/- 14.6 micrograms/ml at the first observation, and 33.1 +/- 15.1 micrograms/ml at the second (NS). In group B, the level of plasma beta 2M was 45.6 +/- 8.13 micrograms/ml at the first observation, and 39.7 +/- 9.18 micrograms/ml at the second (p <0.05). No improvement in DSA was observed. The result of this study suggests that DSA will not improve once it has become overt, and the management for lowering the level of beta 2M may prevent the occurrence and progression of DSA.

Adult↗

[Type III procollagen N-peptide and hyaluronate in serum and dialysate of CAPD patients].

Long-term CAPD may develop peritoneal fibrosis, which is thought to be related to permanent loss of ultrafiltration capacity and sclerosing peritonitis. In CAPD patients, we examined the serum (P-) and effluent (D-) levels of type III procollagen N-peptide (P III P) and hyaluronate (HA), which are expected to change concomitantly with a local increase in submesothelial extracellular matrix of the peritoneum. We selected 40 CAPD patients (age: 46.3 +/- 11.3 years, time on CAPD: 33.6 +/- 26.2 months), who were not suffering from chronic liver disease, any inflammatory disease, nor peritonitis during the previous month. P-P III P, P-HA, D-P III P, and D-HA were measured by PET (values after 4-hour dwelling). D/P ratios (P III P 0.330 +/- 0.137, HA 5.68 +/- 6.44) suggested that their source was from the peritoneum. Although neither P-P III P nor log P-HA value had a significant correlation with age nor time on CAPD, both had significantly positive correlations (p = 0.0009, 0.0005, respectively) with time on total dialysis (including hemodialysis). D-P III P did not have a significant correlation with age nor time on total dialysis but had a significantly positive correlation (p = 0.0098) with D/P-creatinine. Although log D-HA had significantly positive correlations with time on CAPD and time on total dialysis (p = 0.0007, 0.0051, respectively), time on CAPD was first entered (F = 16.5) and time on total dialysis was removed (F to enter: 4) by stepwise regression analysis. In conclusion, a local increase in extracellular matrix of the peritoneum in CAPD patients, indicated by increases in P III P and HA in the effluent, may be related to higher peritoneal permeability and a longer duration of PD.

Adult↗

[A case of primary antiphospholipid antibody syndrome with severe nephrotic syndrome showing remarkable endothelial cell damage in the capillary lumen].

A 25-year-old woman complained of anasarca and was admitted to Sakura National hospital on the presumptive diagnosis of nephrotic syndrome with 10.7 g of 24-hour urinary protein. At first, lupus nephritis with antiphospholipid antibody syndrome was suspected because of prolongation of APTT, existence of lupus anticoagulant and elevation of serum anticardiolipin antibody titer (IgM) in addition to positive ANA, lymphocytopenia and the biologically false positive test for syphilis (BFPTS). On day 28 of hospitalization, renal biopsy findings revealed severe endocapillary cell damage, such as swelling and proliferation of endothelial cells, fragmentation and double contour of the basement membrane walls, which were located only in the capillary lumens with a few thrombi. Immunofluorescent micrography revealed the absence of specific immunoglobulin or complement deposit. Therefore, the diagnosis of lupus nephritis was negated as these findings were suggestive of characteristic glomerulopathy due to primary antiphospholipid antibody syndrome. She was treated initially with oral prednisolone 60 mg and intravenous infusion of heparin 20,000 units daily. Moreover, cyclophosphamide 750 mg was administered intravenously as pulse therapy on day 13 as her serum level of CH50 had fallen suddenly, and hemodialysis was necessary because her renal function had deteriorated and she was suffering from cough and orthopnea with overhydratin. After the combined therapy, BFPTS disappeared and APTT returned to the normal range: dialysis treatment was not required further after the 4th hemodialysis. Thereafter, renal function improved and complete remission of nephrotic syndrome was obtained. This patient was a case of primary antiphospholipid antibody syndrome in which endothelial cell damage was located exclusively in the capillary lumens and pulse cyclophosphamide therapy in addition to prednisolone and anticoagulant was effective. We present this instructive case to promote understanding of the pathogenesis of primary antiphospholipid antibody syndrome.

Adult↗